End machine

Abstract

This technology provides a way to prevent problems from occurring during the use of a binding machine, regardless of the type of wire used in the binding machine. [Solution] The binding machine comprises a feeding mechanism capable of performing a feeding motion to feed wire around the object to be bound, a feeding motor for operating the feeding mechanism, a twisting mechanism capable of performing a twisting motion to twist the wire around the object to be bound, a twisting motor for operating the twisting mechanism, a voltage detection unit for detecting the voltage of a battery that supplies power to the feeding motor and the twisting motor, a wire type detection unit for detecting the type of wire, and a control unit. The control unit is configured to prohibit the driving of at least one of the feeding motor and the twisting motor if the battery voltage value detected by the voltage detection unit is below a certain voltage threshold. The control unit is configured to change the voltage threshold according to the type of wire detected by the wire type detection unit.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a bundling machine.

Background Art

[0002] Patent Document 1 discloses a bundling machine that bundles an object to be bundled using a wire. The bundling machine includes a feeding mechanism capable of executing a feeding motion for sending out the wire around the object to be bundled, a feeding motor for operating the feeding mechanism, a twisting mechanism capable of executing a twisting motion for twisting the wire around the object to be bundled, a twisting motor for operating the twisting mechanism, and a control unit for controlling the operations of each of the feeding motor and the twisting motor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Depending on the type of wire used in the bundling machine, inconveniences may occur when using the bundling machine. The inconveniences referred to here are, for example, that the feeding motion or the twisting motion ends incompletely, the surface of the wire is damaged, and / or the feeding amount by the feeding motion does not reach the desired amount. In this specification, a technology capable of suppressing inconveniences from occurring when using the bundling machine is provided regardless of the type of wire used in the bundling machine.

Means for Solving the Problems

[0005] The binding machine disclosed herein binds objects to be bound using wire. The binding machine comprises a feed mechanism capable of performing a feed motion to feed the wire around the objects to be bound; a feed motor for operating the feed mechanism; a twisting mechanism capable of performing a twisting motion to twist the wire around the objects to be bound; a twisting motor for operating the twisting mechanism; a voltage detection unit for detecting the voltage of a battery that supplies power to the feed motor and the twisting motor, respectively; a wire type detection unit for detecting the type of wire; and a control unit for controlling the operation of the feed motor and the twisting motor, respectively. The control unit is configured to prohibit the driving of at least one of the feed motor and the twisting motor if the voltage value of the battery detected by the voltage detection unit is below a certain voltage threshold. The control unit is configured to change the voltage threshold according to the type of wire detected by the wire type detection unit.

[0006] When the battery voltage drops, the voltage input to the feed motor and torsion motor may be insufficient, preventing them from being driven at the desired output. If the feed motor is driven in this situation to initiate the feed motion in the feed mechanism, the feed motion may terminate prematurely. Similarly, if the torsion motor is driven to initiate the torsion motion in the torsion mechanism, the torsion motion may terminate prematurely. With the above configuration, if the battery voltage falls below a certain voltage threshold (i.e., when the battery voltage drops), driving at least one of the feed motor and torsion motor is prohibited. This prevents each motion from terminating prematurely. However, the output that each motor must exert to complete each motion differs depending on the type of wire used for bundling. For example, when using high-strength wire, the output that each motor must exert to complete each motion is higher than when using low-strength wire. Therefore, if a constant voltage threshold is used regardless of the wire type, while each motion may not terminate prematurely when using a certain wire, it is possible that each motion may terminate prematurely when using a different wire. Furthermore, with the above configuration, the voltage threshold can be changed according to the type of wire used. This allows for setting a voltage threshold that prevents each motion from terminating prematurely, depending on the wire type. For example, the voltage threshold can be set higher when using a high-strength wire and lower when using a low-strength wire. As a result, premature termination of each motion can be suppressed regardless of the wire type.

[0007] Another binding machine disclosed herein binds objects to be bound using wire. The binding machine comprises a feed mechanism capable of performing a feed motion to feed the wire around the objects to be bound; a feed motor for operating the feed mechanism; a twisting mechanism capable of performing a twisting motion to twist the wire around the objects to be bound; a twisting motor for operating the twisting mechanism; a wire type detection unit for detecting the type of wire; and a control unit for controlling the operation of the feed motor and the twisting motor, respectively. The control unit is configured to adjust the voltage applied to the feed motor to a specific target voltage value when driving the feed motor to cause the feed mechanism to perform the feed motion. The control unit is configured to change the target voltage value depending on the type of wire detected by the wire type detection unit.

[0008] If the voltage applied to the feed motor during feed motion is high, the motor's rotation speed increases, which may damage the wire surface. However, the susceptibility of the wire surface to damage varies depending on the type of wire. For example, low-hardness wires are more susceptible to damage than high-hardness wires. Therefore, if a constant target voltage value is used regardless of the wire type, the wire surface may not be damaged when using one type of wire, but it may be damaged when using another. With the above configuration, the target voltage value can be changed according to the type of wire used. This allows setting a target voltage value that prevents damage to the wire surface depending on the type of wire. For example, the target voltage value can be set lower when using low-hardness wires and higher when using high-hardness wires. As a result, damage to the wire surface can be suppressed regardless of the type of wire.

[0009] Another binding machine disclosed herein binds objects to be bound using wire. The binding machine comprises a feed mechanism capable of performing a feed motion to feed the wire around the objects to be bound; a feed motor for operating the feed mechanism; a twisting mechanism capable of performing a twisting motion to twist the wire around the objects to be bound; a twisting motor for operating the twisting mechanism; a wire type detection unit for detecting the type of wire; and a control unit for controlling the operation of the feed motor and the twisting motor, respectively. The control unit is configured to rotate the feed motor by a specific target number of rotations when driving the feed motor to cause the feed mechanism to perform the feed motion during an initialization process to adjust the position of the wire. The control unit is configured to change the target number of rotations depending on the type of wire detected by the wire type detection unit.

[0010] The amount of wire fed by the feed motion (i.e., the distance the wire is moved by the feed mechanism) varies not only depending on the number of rotations of the feed motor but also on the type of wire. For example, when using a wire with a high coefficient of friction, the amount of wire fed by the feed motion will be greater than that of a wire with a low coefficient of friction. This is because the higher the coefficient of friction of the wire, the less likely slippage will occur between the feed mechanism and the wire. Therefore, if a constant target number of rotations is used regardless of the type of wire, the amount of wire fed by the feed motion may not be the desired amount depending on the type of wire. With the above configuration, the target number of rotations can be changed according to the type of wire used. For example, when using a wire with a high coefficient of friction, the target number of rotations can be set lower, and when using a wire with a low coefficient of friction, the target number of rotations can be set higher. This makes it possible to set the amount of wire fed by the feed motion to the desired amount regardless of the type of wire. [Brief explanation of the drawing]

[0011] [Figure 1] This is a view of the rebar tying machine 2 according to Example 1, seen from the rear, upper, and left. [Figure 2]This is a view of the rebar tying machine 2 according to Example 1, with the cover member 16 open, as seen from the front, lower left. [Figure 3] This is a perspective view of the reel 18 attached to the rebar tying machine 2 according to Example 1. [Figure 4] This is a cross-sectional view of the vicinity of the reel holder 12 of the rebar tying machine 2 according to Example 1. [Figure 5] This diagram shows the internal structure of the rebar tying machine 2 according to Example 1. [Figure 6] This is a view of the feeding mechanism 24 of the rebar tying machine 2 according to Example 1, seen from the front, upper, and left. [Figure 7] This is a cross-sectional view of the vicinity of the guide mechanism 26 of the rebar tying machine 2 according to Embodiment 1. [Figure 8] This is a view from the front, upper left, showing the state in which the shearing member 64 of the cutting mechanism 28 of the rebar tying machine 2 according to Embodiment 1 is in a position where it does not extend beyond the wire hole 74. [Figure 9] This is a view from the front, upper left, showing the state in which the shearing member 64 of the cutting mechanism 28 of the rebar tying machine 2 according to Embodiment 1 is positioned beyond the wire hole 74. [Figure 10] This is a view of the twisting mechanism 30 of the rebar tying machine 2 according to Embodiment 1, in its initial position, as seen from the front, upper, and left. [Figure 11] This is a cross-sectional perspective view of the twisting mechanism 30 in its initial position in the rebar tying machine 2 according to Example 1. [Figure 12] This is a view of the vicinity of the rotation limiting unit 86 of the rebar tying machine 2 according to Example 1, seen from the front, upper, and left. [Figure 13] This is a cross-sectional view of the vicinity of the gripping unit 88 of the rebar tying machine 2 according to Example 1. [Figure 14] This is a view from the front, upper, and right of the vicinity of the cutting mechanism 28 and the twisting mechanism 30 when the rebar tying machine 2 according to Embodiment 1 performs a feeding motion. [Figure 15] This is a view from the front, upper, and right of the vicinity of the cutting mechanism 28 and the twisting mechanism 30 when the rebar tying machine 2 according to Embodiment 1 performs a tip gripping motion. [Figure 16]It is a view of the vicinity of the cutting mechanism 28 and the twisting mechanism 30 when the reinforcing bar bundling machine 2 according to Example 1 executes a pulling-back motion, seen from the front, above, and to the right. [Figure 17] It is a view of the vicinity of the cutting mechanism 28 and the twisting mechanism 30 when the reinforcing bar bundling machine 2 according to Example 1 executes a cutting motion, seen from the front, above, and to the right. [Figure 18] It is a view of the vicinity of the cutting mechanism 28 and the twisting mechanism 30 when the reinforcing bar bundling machine 2 according to Example 1 executes a twisting motion, seen from the front, above, and to the right. [Figure 19] It is a view of the vicinity of the rotation limiting unit 86 of the reinforcing bar bundling machine 2 according to Example 1, seen from the front, below, and to the left. [Figure 20] It is a block diagram schematically showing the electrical configuration of the reinforcing bar bundling machine 2 according to Example 1. [Figure 21] It is a flowchart of the main process executed by the control circuit 230 of the reinforcing bar bundling machine 2 according to Example 1. [Figure 22] It is a diagram schematically showing the wire type table stored in the control circuit 230 of the reinforcing bar bundling machine 2 according to Example 1. [Figure 23] It is a flowchart of the initialization process executed by the control circuit 230 of the reinforcing bar bundling machine 2 according to Example 1. [Figure 24] It is a flowchart of the initial position return process executed by the control circuit 230 of the reinforcing bar bundling machine 2 according to Example 1. [Figure 25] It is a flowchart of the cutting trial process executed by the control circuit 230 of the reinforcing bar bundling machine 2 according to Example 1. [Figure 26] It is a graph showing the change over time of the twisting motor current value I while the control circuit 230 of the reinforcing bar bundling machine 2 according to Example 1 executes the cutting trial process. [Figure 27] It is a graph showing the change over time of the twisting motor current value I while the control circuit 230 of the reinforcing bar bundling machine 2 according to Example 1 executes the cutting trial process. [Figure 28] It is a flowchart of the small feed process executed by the control circuit 230 of the reinforcing bar bundling machine 2 according to Example 1. [Figure 29]This is a flowchart of the binding process performed by the control circuit 230 of the rebar binding machine 2 according to Example 1. [Figure 30] This is a flowchart of the feeding process executed by the control circuit 230 of the rebar tying machine 2 according to Example 1. [Figure 31] This is a flowchart of the tip gripping process performed by the control circuit 230 of the rebar tying machine 2 according to Example 1. [Figure 32] This is a flowchart of the pull-back process performed by the control circuit 230 of the rebar tying machine 2 according to Example 1. [Figure 33] This is a flowchart of the cutting and twisting processes performed by the control circuit 230 of the rebar tying machine 2 according to Example 1. [Figure 34] This graph shows the change over time of the torsion motor current value I while the control circuit 230 of the rebar tying machine 2 according to Example 1 is performing the tip gripping process. [Figure 35] This graph shows the change over time of the torsion motor current value I while the control circuit 230 of the rebar tying machine 2 according to Example 1 is performing cutting and torsion processing. [Figure 36] This is a flowchart of the feeding process executed by the control circuit 230 of the rebar tying machine 2 according to Example 2. [Figure 37] This is a flowchart of the tip gripping process performed by the control circuit 230 of the rebar tying machine 2 according to Example 2. [Figure 38] This is a flowchart of the cutting and twisting processes performed by the control circuit 230 of the rebar tying machine 2 according to Example 3. [Modes for carrying out the invention]

[0012] Representative and non-limiting examples of the present invention are described in detail below with reference to the drawings. This detailed description is intended simply to show those skilled in the art details for carrying out preferred examples of the present invention and is not intended to limit the scope of the invention. Furthermore, the disclosed additional features and inventions may be used separately from or in conjunction with other features and inventions to provide a further improved binding machine.

[0013] Furthermore, the combinations of features and processes disclosed in the following detailed description are not essential for carrying out the present invention in the broadest sense, and are described solely to illustrate representative examples of the present invention. Moreover, the various features of the following representative examples, as well as the various features described in the claims, do not necessarily have to be combined in the same way as the examples described herein, or in the order listed, to provide additional and useful embodiments of the present invention.

[0014] All features described herein and / or in the claims are intended to be disclosed individually and independently of each other, as limitations to the specific matters described in the original disclosure and in the claims, separate from the features described in the examples and / or in the claims. Furthermore, all descriptions of numerical ranges and groups or clusters are intended to disclose intermediate configurations as limitations to the specific matters described in the original disclosure and in the claims.

[0015] The binding machine disclosed herein binds objects to be bound using wire. The binding machine comprises a feed mechanism capable of performing a feed motion to feed the wire around the objects to be bound; a feed motor for operating the feed mechanism; a twisting mechanism capable of performing a twisting motion to twist the wire around the objects to be bound; a twisting motor for operating the twisting mechanism; a voltage detection unit for detecting the voltage of a battery that supplies power to the feed motor and the twisting motor, respectively; a wire type detection unit for detecting the type of wire; and a control unit for controlling the operation of the feed motor and the twisting motor, respectively. The control unit is configured to prohibit the driving of at least one of the feed motor and the twisting motor if the voltage value of the battery detected by the voltage detection unit is below a certain voltage threshold. The control unit is configured to change the voltage threshold according to the type of wire detected by the wire type detection unit.

[0016] In one or more embodiments, the wire type detection unit may be configured to distinguish and detect wires having a first maximum tensile load and wires having a second maximum tensile load smaller than the first maximum tensile load. The control unit may be configured to change the voltage threshold depending on whether the wire type detection unit detects a wire having the first maximum tensile load or a wire having the second maximum tensile load.

[0017] When using a wire with a high maximum tensile load, the output that each motor must exert to complete each motion is higher compared to when using a wire with a low maximum tensile load. With the above configuration, the voltage threshold can be changed depending on whether a wire with a high maximum tensile load or a low maximum tensile load is used. For example, the voltage threshold can be set higher when using a wire with a high maximum tensile load and lower when using a wire with a low maximum tensile load. This prevents each motion from ending prematurely, regardless of the maximum tensile load of the wire.

[0018] In one or more embodiments, the control unit may specify that the maximum tensile load of the wire is different when the wire type detection unit detects the wire having the first maximum tensile load compared to when the wire type detection unit detects the wire having the second maximum tensile load.

[0019] With the above configuration, the control unit can identify differences in the maximum tensile load of the wires, and therefore can perform control that matches the maximum tensile load of the wires.

[0020] In one or more embodiments, the ratio of the first maximum tensile load to the second maximum tensile load may be 115% or more.

[0021] With the above configuration, the first maximum tensile load and the second maximum tensile load are clearly different, so the effect of changing the voltage threshold between them is significantly demonstrated.

[0022] In one or more embodiments, the wire type detection unit may be configured to distinguish and detect wires having a first yield load and wires having a second yield load smaller than the first yield load. The control unit may be configured to change the voltage threshold depending on whether the wire type detection unit detects a wire having the first yield load or a wire having the second yield load.

[0023] When using wires with a high yield strength, the output that each motor must exert to complete each motion is higher compared to when using wires with a low yield strength. With the above configuration, the voltage threshold can be changed depending on whether high or low yield strength wires are used. This prevents each motion from ending prematurely, regardless of the wire's yield strength.

[0024] In one or more embodiments, the control unit may determine that the yield load of the wire is different when the wire type detection unit detects the wire having the first yield load compared to when the wire type detection unit detects the wire having the second yield load.

[0025] With the above configuration, the control unit can identify differences in the yield point load of the wires, and therefore can perform control that matches the yield point load of the wires.

[0026] In one or more embodiments, the ratio of the first yield point load to the second yield point load may be 115% or more.

[0027] With the above configuration, the first yield point load and the second yield point load are clearly different, so the effect of changing the voltage threshold between them is significantly demonstrated.

[0028] Another binding machine disclosed herein binds objects to be bound using wire. The binding machine comprises a feed mechanism capable of performing a feed motion to feed the wire around the objects to be bound; a feed motor for operating the feed mechanism; a twisting mechanism capable of performing a twisting motion to twist the wire around the objects to be bound; a twisting motor for operating the twisting mechanism; a wire type detection unit for detecting the type of wire; and a control unit for controlling the operation of the feed motor and the twisting motor, respectively. The control unit is configured to adjust the voltage applied to the feed motor to a specific target voltage value when driving the feed motor to cause the feed mechanism to perform the feed motion. The control unit is configured to change the target voltage value depending on the type of wire detected by the wire type detection unit.

[0029] In one or more embodiments, the wire type detection unit may be configured to distinguish and detect wires having a first hardness and wires having a second hardness less than the first hardness. The control unit may be configured to change the target voltage value depending on whether the wire type detection unit detects a wire having the first hardness or a wire having the second hardness.

[0030] Low-hardness wires are more susceptible to surface scratches compared to high-hardness wires. With the above configuration, the target voltage value can be changed depending on whether a low-hardness wire or a high-hardness wire is used. For example, the target voltage value can be set lower when using a low-hardness wire and higher when using a high-hardness wire. This suppresses surface scratches on the wire regardless of its hardness.

[0031] In one or more embodiments, the control unit may determine that the hardness of the wire differs depending on whether the wire type detection unit detects a wire having a first hardness or a wire having a second hardness.

[0032] With the above configuration, the control unit can identify differences in wire hardness, allowing it to perform control tailored to the wire hardness.

[0033] In one or more embodiments, the ratio of the first hardness to the second hardness may be 115% or more.

[0034] With the above configuration, the first hardness and the second hardness are clearly different, so the effect of changing the target voltage value between them is significantly demonstrated.

[0035] Another binding machine disclosed herein binds objects to be bound using wire. The binding machine comprises a feed mechanism capable of performing a feed motion to feed the wire around the objects to be bound; a feed motor for operating the feed mechanism; a twisting mechanism capable of performing a twisting motion to twist the wire around the objects to be bound; a twisting motor for operating the twisting mechanism; a wire type detection unit for detecting the type of wire; and a control unit for controlling the operation of the feed motor and the twisting motor, respectively. The control unit is configured to rotate the feed motor by a specific target number of rotations when driving the feed motor to cause the feed mechanism to perform the feed motion during an initialization process to adjust the position of the wire. The control unit is configured to change the target number of rotations depending on the type of wire detected by the wire type detection unit.

[0036] In one or more embodiments, the wire type detection unit may be configured to distinguish and detect wires having a coating and wires not having a coating. The control unit may be configured to change the target number of rotations depending on whether the wire type detection unit detects a wire having a coating or a wire not having a coating.

[0037] Wires with coatings tend to be more slippery than wires without coatings. Therefore, when a feeding mechanism feeds a wire with a coating, slippage can occur between the feeding mechanism and the wire, potentially resulting in a feed amount less than the desired amount. With the above configuration, the target number of rotations can be changed depending on whether a wire with a coating or a wire without a coating is used. For example, the target number of rotations can be set higher when using a wire with a coating and lower when using a wire without a coating. This makes it possible to achieve the desired feed amount through the feeding motion, regardless of whether the wire has a coating or not.

[0038] (Example 1) As shown in Figure 1, the rebar tying machine 2 ties multiple reinforcing bars R together using a wire W. The diameter of the wire W used in the rebar tying machine 2 is, for example, in the range of 0.5 mm to 2.5 mm, and is selected according to the diameter of the reinforcing bars R to be tied. For example, when tying small diameter reinforcing bars R of 16 mm or less (e.g., 16 mm in diameter), a wire W with a diameter of 1.6 mm or less (e.g., 0.8 mm) is used, and when tying large diameter reinforcing bars R larger than 16 mm (e.g., 25 mm or 32 mm in diameter), a wire W with a diameter of 1.6 mm or more (e.g., 2.0 mm) is used.

[0039] The rebar tying machine 2 comprises a main body 4, a grip 6, a battery mounting section 10, and a reel holder 12. The grip 6 is a component for the operator to grasp. The grip 6 is located on the lower rear side of the main body 4. The grip 6 is integrally formed with the main body 4. A trigger 8 is attached to the upper front side of the grip 6. Inside the grip 6 is a trigger switch 9 (see Figure 5) that detects whether or not the trigger 8 is pressed. The battery mounting section 10 is located on the lower part of the grip 6. The battery mounting section 10 is integrally formed with the grip 6. A battery pack B is detachably attached to the battery mounting section 10. The battery pack B is, for example, a lithium-ion battery. The reel holder 12 is located on the lower front side of the main body 4. The reel holder 12 is located in front of the grip 6. In this embodiment, the longitudinal direction of the torsion mechanism 30 (see Figures 5 and 10), which will be described later, is referred to as the front-to-back direction, the direction perpendicular to the front-to-back direction is referred to as the up-and-down direction, and the direction perpendicular to both the front-to-back direction and the up-and-down direction is referred to as the left-to-right direction.

[0040] The top surface of the main unit 4 is equipped with a power switch 4a for turning the power of the rebar tying machine 2 on and off, a setting switch 4b for changing various settings such as the tying force of the rebar tying machine 2, and a display unit 4c for displaying information regarding the current settings of the rebar tying machine 2.

[0041] As shown in Figure 2, the reel holder 12 comprises a holder housing 14 and a cover member 16. The holder housing 14 is attached to the front lower part of the main body 4 and the front part of the battery mounting section 10. The cover member 16 is attached to the holder housing 14 so as to be rotatable around a pivot axis 14a at the top of the holder housing 14. The holder housing 14 and the cover member 16 define a housing space 12a. The reel 18 is placed in the housing space 12a. Below the reel 18, the holder housing 14 has a plurality of ribs 15 that protrude from the inner wall of the holder housing 14. The plurality of ribs 15 extend in the left-right direction. The plurality of ribs 15 come into contact with the wire W when the rebar tying machine 2 pulls the wire W back onto the reel 18. This prevents the wire W from coming into contact with the inner wall of the holder housing 14, and thus prevents wear on the inner wall of the holder housing 14.

[0042] As shown in Figure 3, the reel 18 includes a bobbin 200 and a wire W wound around the bobbin 200. The bobbin 200 includes a body portion 202 around which the wire W is wound, a left flange portion 204 extending radially outward from the left end of the body portion 202, a right flange portion 206 extending radially outward from the right end of the body portion 202, a recess 208 recessed to the left from the right surface of the body portion 202, and a projection 210 protruding to the right from the bottom surface of the recess 208.

[0043] As shown in Figure 4, the reel 18 is attached to the reel holder 12 with the support cylinder 212, which is provided inside the holder housing 14, received in the recess 208. The reel 18 is rotatably supported by the support cylinder 212.

[0044] There are various types of wire W used in the rebar tying machine 2. The types of wire W can be distinguished by, for example, the diameter of the wire W, the material of the wire W, the presence or absence of a covering material and the material of the covering material, and the presence or absence of surface treatment on the wire W and the content of the surface treatment.

[0045] The rebar tying machine 2 further includes a wire type detection unit 214 for detecting the type of wire W wound around the bobbin 200. The wire type detection unit 214 is located inside the support cylinder 212. An opening 216 is formed on the left side of the support cylinder 212 for receiving the projection 210 of the bobbin 200 into the support cylinder 212.

[0046] The wire type detection unit 214 comprises a movable member 218, a wire type detection magnet 220, a biasing member 222, and a sensor substrate 224. The wire type detection magnet 220 is fixed to the movable member 218. The movable member 218 is slidable in the left-right direction within a guide space 225 formed inside the support cylinder 212. The movable member 218 is biased to the left by the biasing member 222. When the reel 18 is not attached to the support cylinder 212, the movable member 218 is held at the left end of the guide space 225 by the biasing force of the biasing member 222. When the reel 18 is attached to the support cylinder 212, the projection 210 of the bobbin 200 contacts the left surface of the movable member 218, pushing the movable member 218 to the right against the biasing force of the biasing member 222. This changes the position of the wire type detection magnet 220 fixed to the movable member 218 in the left-right direction. The sensor substrate 224 is equipped with three Hall sensors 226a, 226b, and 226c arranged side by side in the left-right direction. Each of the Hall sensors 226a, 226b, and 226c detects the strength of the magnetic field from the wire type detection magnet 220, outputting an H signal when the detected magnetic field is strong and an L signal when the detected magnetic field is weak. The combination of output signals from the Hall sensors 226a, 226b, and 226c (also called the signal pattern) differs depending on the position of the wire type detection magnet 220. Although not shown, the length of the projection 210 on the bobbin 200 differs depending on the type of wire W wound around the bobbin 200. Therefore, the amount of indentation of the movable member 218 when the reel 18 is attached to the support cylinder 212, and consequently the position of the wire type detection magnet 220, differs depending on the type of wire W wound around the bobbin 200. Furthermore, the output signals from the Hall sensors 226a, 226b, and 226c on the sensor substrate 224 differ depending on the position of the wire type detection magnet 220. Therefore, in this embodiment, the type of wire W wound on the bobbin 200 can be identified from the signal pattern output by the sensor substrate 224 (see Figure 22).

[0047] As shown in Figure 5, the rebar tying machine 2 is equipped with a control board 20. The control board 20 is housed in the battery mounting section 10. The control board 20 controls the operation of the rebar tying machine 2.

[0048] The rebar tying machine 2 includes a feeding mechanism 24, a guide mechanism 26, a cutting mechanism 28 (see Figure 7), a twisting mechanism 30, a feed motor 32, and a twisting motor 76. In this embodiment, the feeding mechanism 24, the guide mechanism 26, the cutting mechanism 28, and the twisting mechanism 30 are collectively referred to as the "tying mechanism 100". The feeding mechanism 24 is housed in the lower front part of the main body 4. The feeding mechanism 24 feeds the wire W to the guide mechanism 26 and pulls the wire W back from the guide mechanism 26. The guide mechanism 26 is located at the front of the main body 4. The guide mechanism 26 guides the wire W fed from the feeding mechanism 24 in a circular pattern around the rebar R. The cutting mechanism 28 is housed in the lower part of the main body 4. The cutting mechanism 28 cuts the wire W when it is wound around the rebar R. The twisting mechanism 30 is housed in the main body 4. The twisting mechanism 30 twists the wire W around the reinforcing bar R. The feed motor 32 is a motor for operating the feed mechanism 24. The twisting motor 76 is a motor for operating the cutting mechanism 28 and the twisting mechanism 30. Each of the feed motor 32 and the twisting motor 76 is connected to the control board 20 by wiring (not shown). Each of the feed motor 32 and the twisting motor 76 is driven by power supplied from the battery pack B. The drive of each of the feed motor 32 and the twisting motor 76 is controlled by the control board 20.

[0049] (Configuration of the feed motor 32) As shown in Figure 6, the feed motor 32 is a brushless motor comprising a stator 32b having teeth (not shown) around which coils 32a are wound, a rotor (not shown) located inside the stator 32b, and an output shaft (not shown) fixed to the rotor. The rotor is equipped with permanent magnets with magnetic poles arranged in a circumferential direction. A rotation detection board 33, on which multiple Hall sensors (not shown) are mounted, is fixed to the stator 32b. The rotation detection board 33 detects the rotation of the feed motor 32 (specifically, the rotation of the rotor) by detecting the magnetic force from the rotor using the multiple Hall sensors.

[0050] (Configuration of the feed mechanism 24) The feed mechanism 24 comprises a reduction gear unit 34 and a feed unit 36. The output shaft of the feed motor 32 is connected to the reduction gear unit 34. The reduction gear unit 34 reduces the rotation of the feed motor 32, for example by a planetary gear mechanism, and transmits it to the drive gear 42 of the feed unit 36.

[0051] The feed unit 36 ​​comprises a base member 38, a guide member 40, a drive gear 42, a first gear 44, a second gear 46, a gear support member 48, and a biasing member 52. The guide member 40 is fixed to the base member 38. The guide member 40 has a guide hole 40a for passing the wire W through. The guide hole 40a has a tapered shape, with a wider lower end and a narrower upper end.

[0052] The drive gear 42 is connected to the reduction gear 34. The first gear 44 is rotatably supported on the base member 38. The first gear 44 meshes with the drive gear 42. The first gear 44 rotates with the rotation of the drive gear 42. The first gear 44 has a groove 44a. The groove 44a is formed on the outer circumferential surface of the first gear 44 in a direction along the rotational direction of the first gear 44. The second gear 46 meshes with the first gear 44. The second gear 46 is rotatably supported on the support portion 48b of the gear support member 48. The second gear 46 has a groove 46a. The groove 46a is formed on the outer circumferential surface of the second gear 46 in a direction along the rotational direction of the second gear 46. The gear support member 48 is pivotably supported on the base member 38 via a pivot shaft 48a. The gear support member 48 comprises a support portion 48b extending upward from the pivot shaft 48a and an operating portion 48c extending downward from the pivot shaft 48a. The biasing member 52 biases the operating portion 48c toward the rear. As a result, the support portion 48b supporting the second gear 46 is biased forward (i.e., toward the first gear 44), and the second gear 46 is pressed against the first gear 44. As a result, the wire W is sandwiched between the groove 44a of the first gear 44 and the groove 46a of the second gear 46. When the operating portion 48c is pushed against the biasing force of the biasing member 52, the second gear 46 moves away from the first gear 44. As a result, when replacing the reel 18, the wire W can be easily passed between the groove 44a of the first gear 44 and the groove 46a of the second gear 46.

[0053] The wire W is moved as the feed motor 32 rotates with the wire W sandwiched between the groove 44a of the first gear 44 and the groove 46a of the second gear 46. In this embodiment, when the feed motor 32 rotates forward, the drive gear 42 rotates in the direction D1 shown in Figure 6, and the wire W is fed out toward the guide mechanism 26. When the feed motor 32 rotates backward, the drive gear 42 rotates in the direction D2 shown in Figure 6, and the wire W is pulled back from the guide mechanism 26.

[0054] (Configuration of the guidance mechanism 26) As shown in Figure 7, the guide mechanism 26 includes a wire guide 56, an upper guide arm 58, and a lower guide arm 60. The wire W, after being fed out from the feeding mechanism 24, passes through the inside of the wire guide 56.

[0055] The upper guide arm 58 is located on the front upper part of the main body 4. The upper guide arm 58 defines the upper guide passage 58a. The wire W that has passed through the inside of the wire guide 56 passes through the upper guide passage 58a. A first guide pin 61 and a second guide pin 62 are arranged in the upper guide passage 58a. As the wire W passes through the upper guide passage 58a while in contact with the first guide pin 61 and the second guide pin 62, a downward coiling tendency is imparted to the wire W.

[0056] The lower guide arm 60 is located at the front lower part of the main body 4. The lower guide arm 60 is made by welding three flat metal plates together. This makes it easier to manufacture the lower guide arm 60 compared to making it by bending a single metal plate. The lower guide arm 60 defines the lower guide passage 60a. The wire W that has passed through the upper guide passage 58a passes through the lower guide passage 60a. In Figure 7, a portion of the wire W that is hidden and not visible due to the lower guide arm 60 and the torsion mechanism 30 is shown by a dashed line.

[0057] (Configuration of the cutting mechanism 28) As shown in Figure 8, the cutting mechanism 28 comprises a shearing member 64, a guide member 66, an operating member 68, and a biasing member 70. The shearing member 64 has a cylindrical shape extending in the front-rear direction. The guide member 66 has a guide passage 72 that slidably receives the shearing member 64 in the front-rear direction. The guide passage 72 extends in the front-rear direction. The guide member 66 also has a wire hole 74 for passing the wire W through. The wire hole 74 opens into the guide passage 72 and extends in a direction intersecting the guide passage 72 (i.e., in the vertical direction). As shown in Figure 7, the wire hole 74 is positioned above the exit of the wire guide 56 of the guide mechanism 26. Therefore, the wire W that has passed through the wire guide 56 passes through the wire hole 74 and then reaches the upper guide passage 58a.

[0058] As shown in Figure 8, the operating member 68 is fixed to the rear end of the shearing member 64. The biasing member 70 biases the operating member 68 backward relative to the guide member 66. Normally, the operating member 68 is held in the position shown in Figure 8 by the biasing force of the biasing member 70. At this time, the shearing member 64 is positioned in the guide passage 72 in a position that does not block the wire hole 74. When a force pushing the operating member 68 forward is applied from the state shown in Figure 8, and this force exceeds the biasing force of the biasing member 70, the operating member 68 moves forward. At this time, the shearing member 64 moves forward along the guide passage 72. As shown in Figure 9, when the shearing member 64 moves forward until it blocks the wire hole 74, the wire W inserted through the wire hole 74 is sheared at the upper end position 74a of the wire hole 74. Therefore, in this embodiment, the upper end position 74a of the wire hole 74 is also called the "cutting position 74a".

[0059] (Configuration of the torsion motor 76) As shown in Figure 10, the torsion motor 76 is a brushless motor comprising a stator 76b having teeth (not shown) around which a coil 76a is wound, a rotor 76c positioned inside the stator 76b, and an output shaft (not shown) fixed to the rotor 76c. The rotor 76c is equipped with permanent magnets with magnetic poles arranged in a circumferential direction. A rotation detection board 78, on which multiple Hall sensors (not shown) are mounted, is fixed to the stator 76b. The rotation detection board 78 detects the rotation of the torsion motor 76 (specifically, the rotation of the rotor 76c) by detecting the magnetic force from the rotor 76c using the multiple Hall sensors. In this embodiment, common parts are used for the torsion motor 76 and the feed motor 32 (see Figure 6).

[0060] (Configuration of the torsion mechanism 30) The torsion mechanism 30 comprises a reduction unit 82, a sleeve unit 84, a rotation limiting unit 86, and a gripping unit 88. The output shaft of the torsion motor 76 is connected to the reduction unit 82. The reduction unit 82 reduces the rotation of the torsion motor 76, for example by a planetary gear mechanism, and transmits it to the screw shaft 92 of the sleeve unit 84 (see Figure 11).

[0061] As shown in Figure 11, the sleeve unit 84 comprises a screw shaft 92, an inner sleeve 94, an outer sleeve 96, and a push member 98. The screw shaft 92 extends along a central axis CX that extends in the front-rear direction. The screw shaft 92 rotates around the central axis CX as the torsion motor 76 rotates. A ball groove 102 is formed on the outer circumferential surface of the screw shaft 92. The ball groove 102 extends spirally in the front-rear direction. A ball 104 is movably held in the ball groove 102.

[0062] The inner sleeve 94 comprises a cylindrical portion 106 and a flange portion 108. The cylindrical portion 106 extends along the central axis CX. A screw shaft 92 is inserted into the cylindrical portion 106. The cylindrical portion 106 has a ball-holding hole 110 that penetrates the cylindrical portion 106 in the thickness direction. The ball-holding hole 110 rotatably holds a ball 104 in a ball groove 102. The flange portion 108 protrudes radially outward from the rear end of the cylindrical portion 106.

[0063] The outer sleeve 96 extends along the central axis CX. The cylindrical portion 106 of the inner sleeve 94 is inserted into the outer sleeve 96. The outer sleeve 96 is fixed to the cylindrical portion 106 of the inner sleeve 94 by a pin (not shown). As a result, the outer sleeve 96 moves in the front-rear direction and rotates with the inner sleeve 94. The rear end of the outer sleeve 96 abuts against the front surface of the flange portion 108 of the inner sleeve 94. The outer sleeve 96 contacts the ball 104 from the radially outer side of the central axis CX, thereby preventing the ball 104 from coming out of the ball groove 102 and the ball retaining hole 110.

[0064] The outer sleeve 96 comprises a narrow diameter portion 112 and a wider diameter portion 114 located behind the narrow diameter portion 112. The narrow diameter portion 112 is inserted into a ring sleeve 116 fixed to the main body 4. The ring sleeve 116 receives the outer sleeve 96 so that it can rotate around the central axis CX.

[0065] A push member 98 is positioned at the step between the large diameter portion 114 and the small diameter portion 112. The push member 98 has a roughly plate shape. In the front-rear direction, the push member 98 is sandwiched between the step between the large diameter portion 114 and the small diameter portion 112 and the C-ring 118 attached to the small diameter portion 112. As a result, the push member 98 is immobile in the front-rear direction relative to the outer sleeve 96. When the outer sleeve 96 moves in the front-rear direction relative to the main body 4, the push member 98 moves in the front-rear direction together with the outer sleeve 96. Furthermore, the push member 98 is immobile relative to the main body 4. Therefore, even if the outer sleeve 96 rotates relative to the main body 4, the push member 98 does not rotate around the central axis CX.

[0066] As the push member 98 moves forward together with the outer sleeve 96, it comes into contact with the operating member 68 of the cutting mechanism 28 shown in Figure 8, pushing the operating member 68 forward against the biasing force of the biasing member 70. This causes the cutting motion of the cutting mechanism 28 to be executed.

[0067] As shown in Figure 12, eight fins 120 are formed on the outer circumferential surface of the large-diameter portion 114. Each of the eight fins 120 protrudes radially outward from the outer circumferential surface of the large-diameter portion 114. The eight fins 120 are arranged around the outer circumferential surface of the large-diameter portion 114 at 45-degree intervals from each other. The eight fins 120 consist of seven short fins 122 and one long fin 124. The length of the long fin 124 in the front-rear direction is longer than the length of the short fins 122 in the front-rear direction. In the front-rear direction, the position of the rear end of the long fin 124 is the same as the position of the rear end of the short fin 122. On the other hand, in the front-rear direction, the front end of the long fin 124 is in front of the front end of the short fin 122. The eight fins 120 cooperate with the rotation limiting unit 86 to allow or prohibit the rotation of the outer sleeve 96.

[0068] The rotation limiting unit 86 includes a left stopper 126L and a right stopper 126R. The left stopper 126L includes a base member 128L, a swinging member 130L, and a torsion spring 132L. A screw hole 128a is formed in the base member 128L. A screw 128b (see Figure 1), which is inserted through a through hole (not shown) formed in the housing (see Figure 1), is screwed into the screw hole 128a. This fixes the base member 128L to the housing. The swinging member 130L is swingably supported on the base member 128L via a swing shaft 134L that extends in the front-rear direction. The swinging member 130L includes a regulating piece 136L that extends in the front-rear direction. The regulating piece 136L is positioned above the swing shaft 134L and to the right of the base member 128L. The torsion spring 132L biases the restricting piece 136L in a direction that separates it from the base member 128L (i.e., to the right). The right-side stopper 126R comprises the base member 128R, the oscillating member 130R, and the torsion spring 132R. The base member 128R is also fixed to the housing in the same way as the base member 128L. The oscillating member 130R is pivotably supported on the base member 128R via an oscillating shaft 134R that extends in the front-rear direction. The oscillating member 130R includes a restricting piece 136R that extends in the front-rear direction. The restricting piece 136R is located above the oscillating shaft 134R and to the left of the base member 128R. The torsion spring 132R biases the restricting piece 136R in a direction that separates it from the base member 128R (i.e., to the left).

[0069] When the screw shaft 92 (see Figure 11) rotates in the right-hand thread direction D3, the fins 120 contact the upper surface of the restricting piece 136R, thereby preventing the rotation of the outer sleeve 96. At this time, the inner sleeve 94 and outer sleeve 96 move forward as the ball 104 (see Figure 11) moves within the ball groove 102 (see Figure 11) in conjunction with the rotation of the screw shaft 92. On the other hand, when the screw shaft 92 rotates in the left-hand thread direction D4, the fins 120 contact the restricting piece 136R but push the restricting piece 136R to the right. At this time, the rotation of the outer sleeve 96 is not prevented, and the inner sleeve 94 and outer sleeve 96 rotate together with the screw shaft 92 in the left-hand thread direction D4.

[0070] When the screw shaft 92 (see Figure 11) rotates in the right-hand thread direction D3, the fins 120 push the restricting piece 136L to the left even when they come into contact with it. At this time, the rotation of the outer sleeve 96 is not prohibited, and the inner sleeve 94 and outer sleeve 96 rotate together with the screw shaft 92 in the right-hand thread direction D3. On the other hand, when the screw shaft 92 rotates in the left-hand thread direction D4, the rotation of the outer sleeve 96 is prohibited when the fins 120 come into contact with the upper surface of the restricting piece 136L. At this time, the inner sleeve 94 and outer sleeve 96 move backward as the screw shaft 92 rotates, causing the ball 104 (see Figure 11) to move within the ball groove 102 (see Figure 11).

[0071] As shown in Figure 10, the gripping unit 88 protrudes forward (towards the reinforcing bar R) from the front of the sleeve unit 84. The gripping unit 88 extends along the central axis CX. The gripping unit 88 comprises a clamp shaft 152, a right-side clamp member 154, and a left-side clamp member 156.

[0072] As shown in Figure 11, the clamp shaft 152 is inserted into the inner sleeve 94 and the outer sleeve 96. The clamp shaft 152 is positioned on the central axis CX. A cavity 152a is formed at the rear end of the clamp shaft 152 to receive the screw shaft 92 so that it can rotate around the central axis CX. The clamp shaft 152 is rotatable around the central axis CX relative to the screw shaft 92, but cannot move in the front-rear direction.

[0073] The clamp shaft 152 comprises a flat plate portion 158, a fitting hole 160, and a housing hole 162. The flat plate portion 158 is located at the front of the clamp shaft 152. The flat plate portion 158 has a substantially flat shape along the vertical and front-to-back directions. The fitting hole 160 penetrates the flat plate portion 158 in the thickness direction (i.e., the left-to-right direction). The fitting hole 160 engages with the pin 164. The housing hole 162 is located behind the flat plate portion 158. The housing hole 162 penetrates the clamp shaft 152 in the left-to-right direction and extends in the front-to-back direction.

[0074] As shown in Figure 13, the right-side clamp member 154 is attached to the clamp shaft 152 so as to pass through the housing hole 162 (see Figure 11) of the clamp shaft 152 from right to left. The left-side clamp member 156 is attached to the clamp shaft 152 so as to pass through the housing hole 162 from left to right.

[0075] The right-side clamp member 154 comprises a base portion 166, a pin holding portion 168, and a clamp piece 170. The base portion 166 has a substantially flat plate shape that extends along the front-rear and left-right directions. Cam holes 166a and 166b are formed in the base portion 166. The cam holes 166a and 166b extend forward from the rear end, then bend and extend to the right front, then bend and extend forward again, then bend and extend to the right front, and then bend and extend forward again. The pin holding portion 168 is located near the right front end of the base portion 166. The pin holding portion 168 is located on the upper surface of the base portion 166. The pin holding portion 168 slidably holds the pin 164. The clamp piece 170 extends forward from the right front end of the base portion 166.

[0076] The left clamp member 156 comprises a base portion 178 and a clamp piece 180. The base portion 178 has a substantially flat plate shape that is aligned in the front-rear direction and the left-right direction. Cam holes 178a and 178b are formed in the base portion 178. The cam holes 178a and 178b extend forward from the rear end, then bend and extend to the left front, and then bend again and extend forward. The clamp piece 180 extends forward from the left front end of the base portion 178.

[0077] The base portion 166 of the right clamp member 154 and the base portion 178 of the left clamp member 156 are inserted into the housing hole 162 (see Figure 11) of the clamp shaft 152. In this state, the engagement pin 182a is positioned in the cam holes 166a and 178a. The engagement pin 182a is fixed to the outer sleeve 96 and is movable in the front-rear direction within the cam holes 166a and 178a. Additionally, the engagement pin 182b is positioned in the cam holes 166b and 178b. The engagement pin 182b is fixed to the outer sleeve 96 and is movable in the front-rear direction within the cam holes 166b and 178b. The gripping unit 88 is connected to the outer sleeve 96 via the engagement pins 182a and 182b so as to be immobile around the central axis CX and movable in the front-rear direction relative to the outer sleeve 96.

[0078] When the torsion mechanism 30 is in its initial position, the right-side clamp member 154 is located furthest to the right relative to the clamp shaft 152. In this case, a right-side wire passage 184 is formed between the clamp piece 170 of the right-side clamp member 154 and the flat plate portion 158 of the clamp shaft 152, through which the wire W can pass. From this state, when the outer sleeve 96 moves forward, the engagement pins 182a and 182b move forward along the cam holes 166a and 166b. As a result, the right-side clamp member 154 moves to the left, closing the right-side wire passage 184. The gripping unit 88 grips the wire W passing through the right-side wire passage 184 by closing the right-side wire passage 184 (see Figures 17-18).

[0079] Furthermore, when the torsion mechanism 30 is in its initial position, the left clamp member 156 is located furthest to the left relative to the clamp shaft 152. In this case, a left wire passage 186 is formed between the clamp piece 180 of the left clamp member 156 and the flat plate portion 158 of the clamp shaft 152, through which the wire W can pass. From this state, when the outer sleeve 96 moves forward, the engagement pins 182a and 182b move forward along the cam holes 178a and 178b. As a result, the left clamp member 156 moves to the right, closing the left wire passage 186. The gripping unit 88 grips the wire W passing through the left wire passage 186 by closing the left wire passage 186 (see Figures 15-18).

[0080] (Mechanical operation of rebar tying machine 2 during tying operation) Next, referring to Figures 14-18, the mechanical operation of the rebar tying machine 2 during the tying operation in which the rebar R is tied with wire W will be described. During the tying operation, the rebar tying machine 2 sequentially performs the following motions: feeding motion, tip gripping motion, pull-back motion, cutting motion, twisting motion, and initial position return motion. Here, the position of the twisting mechanism 30 when the rebar tying machine 2 starts the tying operation is called the "initial position". When the twisting mechanism 30 is in the initial position, the long fin 124 is in contact with the upper surface of the restricting piece 136L of the left stopper 126L. The push member 98 is away from the operating member 68 of the cutting mechanism 28 (see Figure 8). As shown in Figure 13, the engagement pin 182a is located at the rear of each of the cam holes 166a and 178a, and the engagement pin 182b is located at the rear of the cam holes 166b and 178b.

[0081] (Sending motion) When the feed motor 32 rotates forward from the initial position of the twisting mechanism 30, the feed mechanism 24 feeds out the wire W wound on the reel 18. In this case, the tip of the wire W passes through the wire guide 56 of the guide mechanism 26, the wire hole 74 of the cutting mechanism 28, the right wire passage 184 of the twisting mechanism 30, the upper guide passage 58a of the guide mechanism 26, the lower guide passage 60a of the guide mechanism 26, and the left wire passage 186 of the twisting mechanism 30 in that order. As a result, the wire W is wound in a ring shape around the reinforcing bar R, as shown in Figure 14.

[0082] (Tip gripping motion) From this state, when the torsion motor 76 rotates in the forward direction, the screw shaft 92 rotates in the right-hand thread direction D3. As a result, the outer sleeve 96 rotates in the right-hand thread direction D3, and eventually the short fin 122 comes into contact with the upper surface of the restricting piece 136R (see Figure 12) of the right-side stopper 126R, preventing the outer sleeve 96 from rotating in the right-hand thread direction D3. In this case, the outer sleeve 96, together with the inner sleeve 94, moves forward relative to the gripping unit 88. As the outer sleeve 96 moves forward, the engagement pin 182a moves to the middle part of the cam holes 166a and 178a, and the engagement pin 182b moves to the middle part of the cam holes 166b and 178b. At this time, due to the difference in shape between the cam holes 166a and 166b and the cam holes 178a and 178b, the left wire passage 186 closes before the right wire passage 184 closes. As a result, as shown in Figure 15, the left wire passage 186 is completely closed, but the right wire passage 184 is not completely closed. This allows the gripping unit 88 to grip the portion of the wire W that is in the left wire passage 186 (i.e., near the tip of the wire W). In the state shown in Figure 15, the wire W is prevented from leaving the right wire passage 184, but it is allowed to move within the right wire passage 184.

[0083] (Pullback motion) From this state, when the torsion motor 76 stops and the feed motor 32 rotates in the reverse direction, the feed unit 36 ​​pulls the wire W back around the reinforcing bar R. Because the gripping unit 88 grips the vicinity of the tip of the wire W, the wire W shrinks in diameter around the reinforcing bar R as it is pulled back. As a result, the wire W becomes tightly attached to the reinforcing bar R, as shown in Figure 16.

[0084] (Cutting motion) From this state, when the torsion motor 76 rotates forward again, the outer sleeve 96 moves forward, and the push member 98 (see Figure 10) pushes the operating member 68 forward, causing the shearing member 64 to move forward to a position where it closes the wire hole 74. As a result, the wire W is cut at the cutting position 74a, as shown in Figure 17. Also, as the outer sleeve 96 moves forward, the engagement pin 182a moves to the front of the cam holes 166a and 178a, and the engagement pin 182b moves to the front of the cam holes 166b and 178b. As a result, both the left wire passage 186 and the right wire passage 184 are completely closed. As a result, the gripping unit 88 grips the portion of the wire W in the left wire passage 186 and the portion of the wire W in the right wire passage 184. In other words, the gripping unit 88 grips the wire W at two points: near the tip of the wire W and near the rear end of the wire W.

[0085] (Twisting motion) From this state, as the torsion motor 76 rotates forward, the outer sleeve 96 moves further forward, causing the rear end of the fin 120 (see Figure 12) to move ahead of the front end of the restricting piece 136R (see Figure 12), so that the fin 120 no longer contacts the restricting piece 136R. This allows the outer sleeve 96 to rotate in the direction D3 of the right-hand thread. Subsequently, as the torsion motor 76 rotates forward, the outer sleeve 96 rotates in the direction D3 of the right-hand thread. The gripping unit 88, which is non-rotatably connected to the outer sleeve 96, also rotates in the direction D3 of the right-hand thread. As a result, the wire W gripped by the gripping unit 88 is twisted, as shown in Figure 18.

[0086] (Return to initial position motion) Subsequently, the torsion motor 76 rotates in the reverse direction, causing the screw shaft 92 to rotate in the left-hand thread direction D4. This causes the outer sleeve 96 to rotate in the left-hand thread direction D4, and eventually the short fin 122 (see Figure 12) or long fin 124 (see Figure 12) comes into contact with the upper surface of the restricting piece 136L (see Figure 12) of the left-side stopper 126L, preventing the outer sleeve 96 from rotating in the left-hand thread direction D4. In this case, the outer sleeve 96, together with the inner sleeve 94, retracts relative to the gripping unit 88. As the outer sleeve 96 retracts, the engagement pin 182a moves backward within the cam holes 166a and 178a, and the engagement pin 182b moves backward within the cam holes 166b and 178b. This opens the right-side wire passage 184 and the left-side wire passage 186, and the wire W that was being gripped by the gripping unit 88 is released from the gripping unit 88. If the short fin 122 is in contact with the restricting piece 136L, as the outer sleeve 96 retracts, the front end of the short fin 122 will eventually move behind the rear end of the restricting piece 136L. As a result, the short fin 122 will no longer be in contact with the restricting piece 136L, and the outer sleeve 96 will rotate again in the left-hand thread direction D4. Subsequently, when the long fin 124 comes into contact with the upper surface of the restricting piece 136L, the rotation of the outer sleeve 96 is prohibited again. As a result, the torsion mechanism 30 returns to its initial position (see Figure 10). On the other hand, if the long fin 124 is in contact with the restricting piece 136L, after the outer sleeve 96 begins to retract, the contact between the long fin 124 and the restricting piece 136L is not released, and the torsion mechanism 30 returns to its initial position.

[0087] As shown in Figure 19, the twisting mechanism 30 further comprises an initial position detection magnet 140a, a tip gripping position detection magnet 140b, and a twisting start detection magnet 140c. The initial position detection magnet 140a and the tip gripping position detection magnet 140b are attached to the left side of the push member 98. The twisting start detection magnet 140c is attached to the lower surface of the oscillating member 130L of the left stopper 126L.

[0088] As shown in Figure 20, the rebar tying machine 2 further includes an initial position detection sensor 142a that detects the strength of the magnetic field from the initial position detection magnet 140a, a tip gripping position detection sensor 142b that detects the strength of the magnetic field from the tip gripping position detection magnet 140b, and a twisting start detection sensor 142c that detects the strength of the magnetic field from the twisting start detection magnet 140c. Although not shown, each of the sensors 142a, 142b, and 142c is fixed in position relative to the main body 4.

[0089] The initial position detection sensor 142a is positioned to face the initial position detection magnet 140a (see Figure 19) when the twisting mechanism 30 is in its initial position (see Figure 10). Therefore, the magnetic field from the initial position detection magnet 140a detected by the initial position detection sensor 142a is strongest when the twisting mechanism 30 is in its initial position. Thus, the initial position detection sensor 142a detects whether the twisting mechanism 30 is in its initial position by detecting whether the magnetic field from the initial position detection magnet 140a is strong or not. In addition, the tip gripping position detection sensor 142b is positioned to face the tip gripping position detection magnet 140b (see Figure 19) when the twisting mechanism 30 is in the tip gripping position (see Figure 15) where it grips the tip of the wire W during the bundling operation. The magnetic field from the tip gripping position detection magnet 140b detected by the tip gripping position detection sensor 142b is strongest when the twisting mechanism 30 is in the gripping position. Therefore, the tip gripping position detection sensor 142b detects whether the torsion mechanism 30 is in the tip gripping position by detecting whether the magnetic field from the tip gripping position detection magnet 140b is strong or not. Furthermore, the torsion start detection sensor 142c is positioned below the oscillating member 130L (see Figure 19). Until the torsion mechanism 30 moves from its initial position and begins torsion motion, the oscillating member 130L does not oscillate, so the torsion start detection sensor 142c faces the torsion start detection magnet 140c (see Figure 19) positioned on the lower surface of the oscillating member 130L. When the torsion mechanism 30 begins torsion motion, the restricting piece 136L of the oscillating member 130L is pushed to the left by the fin 120 (see Figure 12), so the torsion start detection sensor 142c and the torsion start detection magnet 140c no longer face each other. At this time, the strength of the magnetic field detected by the torsion start detection sensor 142c fluctuates. Therefore, the torsion start detection sensor 142c detects whether or not the torsion mechanism 30 has started torsion motion by detecting whether or not the detected magnetic field strength has changed.

[0090] (Configuration of the control board 20) As shown in Figure 20, the control board 20 includes a control circuit 230, a power supply circuit 232, a motor current detection circuit 234, and a battery voltage detection circuit 236.

[0091] The control circuit 230 includes a processor and memory consisting of ROM, RAM, etc. The ROM stores a program for controlling the rebar tying machine 2. The RAM temporarily stores various signals input to the control board 20 and various data generated during the process of the processor executing processing. The processor is configured to control the rebar tying machine 2 by executing processing based on the information stored in the memory.

[0092] The power supply circuit 232 adjusts the power supplied from the battery pack B to a predetermined voltage and supplies it to each part of the rebar tying machine 2 (for example, the feed motor 32 and the torsion motor 76).

[0093] The motor current detection circuit 234 detects the current flowing through the feed motor 32 and the current flowing through the torsion motor 76. The motor current detection circuit 234 is a circuit that measures the current values ​​flowing through the feed motor 32 and the current values ​​flowing through the torsion motor 76.

[0094] The battery voltage detection circuit 236 detects the voltage of battery pack B (i.e., the remaining battery charge). The battery voltage detection circuit 236 may be a circuit that measures the voltage value of battery pack B, or it may be a circuit that communicates with battery pack B and acquires the voltage value measured by a voltage measuring instrument (not shown) provided in battery pack B.

[0095] (Main process: Figure 21) The control circuit 230 repeatedly executes the main process when the power to the rebar tying machine 2 is turned on.

[0096] In S2, the control circuit 230 performs wire type identification processing. In wire type identification processing, the control circuit 230 identifies the type of wire W from the signal pattern output by the sensor board 224 of the wire type detection unit 214. The control circuit 230 stores a wire type table as shown in Figure 22. The wire type table describes the relationship between the signal pattern and the type of wire W. Therefore, the control circuit 230 identifies the type of wire W by referring to the wire type table. In this embodiment, the types of wire W are distinguished and identified as three types: annealed wire (i.e., wire W made mainly of iron that has been annealed), polycoated wire (i.e., annealed wire coated with polyester resin), and stainless steel wire (wire W made mainly of stainless steel). In this embodiment, the above three types of wire W are further classified into high-strength wire W and low-strength wire W. For example, they are classified based on the relative magnitudes of the maximum tensile loads of each wire. Alternatively, they are classified based on the relative magnitudes of the yield point loads of each wire. According to this, annealed wire is classified as low-strength wire W, poly-coated wire is classified as low-strength wire W, and stainless steel wire is classified as high-strength wire W. The maximum tensile load and yield point load of stainless steel wire are 115% or more of the maximum tensile load and yield point load of annealed wire and poly-coated wire, respectively. In this embodiment, the three types of wire W are further classified into high-hardness wire W, medium-hardness wire W, and low-hardness wire W. For example, they are classified based on the relative magnitudes of the Vickers hardness of each wire. According to this, annealed wire is classified as medium-hardness wire W, poly-coated wire is classified as low-hardness wire W, and stainless steel wire is classified as high-hardness wire W. The hardness (i.e., Vickers hardness) of stainless steel wire is 115% or more of the hardness (i.e., Vickers hardness) of poly-coated wire. After S2 shown in Figure 21, the process proceeds to S4.

[0097] In S4, the control circuit 230 determines whether the type of wire W was identified in the wire type identification process performed in S2. For example, if the reel 18 is not attached to the reel holder 12, the control circuit determines that the type of wire W is not identified in the wire type identification process (i.e., NO). If the type of wire W is identified (YES), the process proceeds to S6.

[0098] In S6, the control circuit 230 determines whether the battery voltage detected by the battery voltage detection circuit 236 is below a specific first voltage threshold V1. Here, the control circuit 230 determines whether the battery voltage is low. If the battery voltage is low, the feed motor 32 or the torsion motor 76 cannot be driven at the desired output, and the initialization process may terminate prematurely. If the battery voltage is above the first voltage threshold V1 (NO), the process proceeds to S8.

[0099] In S8, the control circuit 230 performs an initialization process as preparation for the bundling operation. As will be described in detail later, the initialization process aligns the tip position of the wire W to a predetermined position (specifically, the cutting position 74a shown in Figure 7) and sets the twisting mechanism 30 to its initial position. After S8, the process proceeds to S10.

[0100] In S10, the control circuit 230 determines whether the battery voltage has fallen below a specific second voltage threshold V2 during the initialization process. When either the feed motor 32 or the torsion motor 76 is driven during the initialization process, the battery voltage temporarily decreases due to the internal resistance of the driven motor. Therefore, in S10, the control circuit 230 determines whether the battery voltage has decreased, taking into account the decrease in battery voltage due to the internal resistance of the motor. If the battery voltage is below the second voltage threshold V2 (YES), the process proceeds to S12.

[0101] In S12, the control circuit 230 sets a low voltage flag to indicate that the battery voltage is low. The low voltage flag is cleared when the error handling described later (processing in S30) is performed. After S12, the process proceeds to S14.

[0102] In S14, the control circuit 230 determines whether the trigger 8 has been pressed and the trigger switch 9 has been turned on. If the trigger 8 is not pressed and the trigger switch 9 is off (NO), the process repeats S14. If the trigger switch 9 is turned on (YES), the process proceeds to S16.

[0103] In S16, the control circuit 230 performs line type identification processing. This line type identification processing is the same as that described in S2. After S16, the process proceeds to S18.

[0104] In S18, the control circuit 230 determines whether the type of wire W was identified in the wire type identification process performed in S16. For example, if the reel 18 is not attached to the reel holder 12, the control circuit determines that the type of wire W is not identified in the wire type identification process (i.e., NO). If the type of wire W is identified (YES), the process proceeds to S20.

[0105] In S20, the control circuit 230 determines whether the low voltage flag is set or not. If the low voltage flag is not set (NO), the process proceeds to S22.

[0106] In S22, the control circuit 230 determines whether the battery voltage is below the first voltage threshold V1. The first voltage threshold V1 is the same as the one described in S6. In S22, the control circuit 230 determines whether the battery voltage is decreasing. If the battery voltage is above the first voltage threshold V1 (NO), the process proceeds to S24.

[0107] In S24, the control circuit 230 performs a tying process to cause the rebar tying machine 2 to perform a tying operation. As will be explained in detail later, by performing the tying process, the rebar tying machine 2 ties the rebar R with wire W. After S24, the process proceeds to S26.

[0108] In S26, the control circuit 230 determines whether the battery voltage has fallen below a specific second voltage threshold V2 during the binding process. The second voltage threshold V2 is the same as that described in S10. When either the feed motor 32 or the torsion motor 76 is driven during the binding process, the battery voltage temporarily decreases due to the internal resistance of the driven motor. Therefore, in S26, the control circuit 230 determines whether the battery voltage has decreased, taking into account the decrease in battery voltage due to the internal resistance of the motor. If the battery voltage is below the second voltage threshold V2 (YES), the process proceeds to S28.

[0109] In S28, the control circuit 230 sets the low voltage flag unless it has already been set. The low voltage flag is cleared when the error handling described later (processing in S30) is performed. After S28, the process returns to S14.

[0110] If the type of wire W is not identified in S4 (NO), if the battery voltage is less than or equal to the first voltage threshold V1 in S6 (YES), if the type of wire W is not identified in S18 (NO), if the low voltage flag is set in S20 (YES), or if the battery voltage is less than or equal to the first voltage threshold V1 in S22 (YES), the process proceeds to S30. In S30, the control circuit 230 performs error processing. During error processing, the control circuit 230 displays the error details (for example, that the type of wire W was not identified, or that the battery voltage is low) on the display unit 4c. The control circuit 230 also disables the driving of the feed motor 32 and the torsion motor 76. Error processing continues, for example, until the power to the rebar tying machine 2 is turned off.

[0111] (Regarding parameter changes related to the main process) The control circuit 230 changes the first voltage threshold V1 and the second voltage threshold V2 according to the type of wire W identified in the wire type identification process. Specifically, the control circuit 230 sets the voltage thresholds V1 and V2 set for stainless steel wire (i.e., high-strength wire W) higher than the voltage thresholds V1 and V2 set for annealed wire and poly-coated wire (i.e., low-strength wire W). When feeding (or twisting) high-strength wire W, higher output is required compared to when feeding (or twisting) low-strength wire W. Therefore, when high-strength wire W is used, the voltage thresholds V1 and V2 are increased to allow error processing caused by a drop in battery voltage to be executed earlier. This prevents the feeding motion (or twisting motion) by the rebar tying machine 2 from ending prematurely. On the other hand, when low-strength wire W is used, the voltage thresholds V1 and V2 are lowered to use up the battery voltage as much as possible. This reduces the frequency of battery pack B replacement.

[0112] (Initialization process: Figure 23) The initialization process is performed in S8 of the main process (see Figure 21).

[0113] In S50, the control circuit 230 executes an initial position return process to return the torsion mechanism 30 to its initial position, unless the torsion mechanism 30 is already in its initial position.

[0114] (Initial position return process: Figure 24) When the initial position return process begins, the process proceeds to S52.

[0115] In S52, the control circuit 230 drives the torsion motor 76 to rotate in the reverse direction. This causes the torsion mechanism 30 to move toward its initial position. Specifically, the screw shaft 92 rotates in the left-hand thread direction D4, and the outer sleeve 96 retracts. When driving the torsion motor 76, the control circuit 230 performs control (also called constant voltage control) to adjust the voltage applied to the torsion motor 76 to a specific target voltage value. The control circuit 230 also continues to drive the torsion motor 76, which was driven in S52, until it stops in S56. After S52, the process proceeds to S54.

[0116] In S54, the control circuit 230 determines whether the torsion mechanism 30 has reached its initial position based on the detection result from the initial position detection sensor 142a. If the torsion mechanism 30 has not reached its initial position (NO), the process repeats S54. While S54 is repeated, the torsion mechanism 30 moves toward its initial position. If the torsion mechanism 30 reaches its initial position (YES), the process proceeds to S56.

[0117] In S56, the control circuit 230 stops the torsion motor 76. After S56, the initial position return process ends. Once the initial position return process is complete, the process proceeds to S60 shown in Figure 23. In S60, the control circuit 230 performs a cutting trial process to attempt to cut the wire W.

[0118] (Cutting trial process: Figure 25) Once the cutting trial process is initiated, the process proceeds to S62.

[0119] In S62, the control circuit 230 drives the torsion motor 76 to rotate in the forward direction. This causes the screw shaft 92 to rotate in the right-hand thread direction D3, the outer sleeve 96 to move forward, and the cutting mechanism 28 to begin the cutting motion. That is, the shear member 64 moves forward along the guide passage 72. When driving the torsion motor 76, the control circuit 230 performs control (also called constant voltage control) to adjust the voltage value applied to the torsion motor 76 to a specific target voltage value. The control circuit 230 also continues to drive the torsion motor 76, which was driven in S62, until it is stopped in S76. After S62, the process proceeds to S64.

[0120] In S64, the control circuit 230 determines whether the elapsed time since the torsion motor 76 was started in S62 (i.e., the driving time of the torsion motor 76) exceeds the first predetermined time T1. If the driving time of the torsion motor 76 is less than or equal to the first predetermined time T1 (NO), the process repeats S64. The first predetermined time T1 is the time to wait until the starting current flowing to the torsion motor 76 exceeds its peak. If the driving time of the torsion motor 76 exceeds the first predetermined time T1 (YES), the process proceeds to S66.

[0121] In S66, the control circuit 230 calculates a current threshold Ith to be used in subsequent processing based on the current value flowing through the torsion motor 76. For example, the control circuit 230 calculates the current threshold Ith by adding a predetermined value to the average value of the current value flowing through the torsion motor 76 during the period in which S66 and S68 are repeated. After S66, the process proceeds to S68.

[0122] In S68, the control circuit 230 determines whether the driving time of the torsion motor 76 exceeds the second predetermined time T2, which is longer than the first predetermined time T1. If the driving time of the torsion motor 76 is less than or equal to the second predetermined time T2 (NO), the process returns to S66. If the driving time of the torsion motor 76 exceeds the second predetermined time T2 (YES), the process proceeds to S70.

[0123] In S70, the control circuit 230 determines whether the current value flowing through the torsion motor 76 (i.e., the torsion motor current value I) has remained above the current threshold Ith calculated in S66 for a predetermined period of time. When the cutting mechanism 28 cuts the wire W, the load on the torsion motor 76 via the cutting mechanism 28 increases. In this case, since the control circuit 230 controls the torsion motor 76 with a constant voltage, the torsion motor current value I increases as the load on the torsion motor 76 increases. Therefore, as shown in Figure 26, the torsion motor current value I increases again after exceeding the peak of the starting current. From this, if the state in S70 where the torsion motor current value I exceeds the current threshold Ith continues for a predetermined period of time (YES), it can be inferred that the cutting mechanism 28 has cut the wire W. On the other hand, if the cutting mechanism 28 does not cut the wire W, no large load is placed on the torsion motor 76. Therefore, as shown in Figure 27, the torsion motor current value I does not increase again after exceeding the peak of the starting current. From this, if the state in S70 where the torsion motor current value I exceeds the current threshold Ith does not continue for a predetermined time (NO), it can be inferred that the cutting mechanism 28 has not cut the wire W. Accordingly, in S70 shown in Figure 25, it can be said that the control circuit 230 is determining whether or not the cutting mechanism 28 has cut the wire W. If the state where the torsion motor current value I exceeds the current threshold Ith continues for a predetermined time (YES), the process proceeds to S72.

[0124] In S72, the control circuit 230 sets a cutting completion flag indicating that the cutting mechanism 28 has cut the wire W. The cutting completion flag is cleared, for example, when the initialization process (see Figure 23) is completed. After S72, the process proceeds to S74.

[0125] If the torsion motor current value I does not remain above the current threshold Ith for a predetermined time in S70 (NO), or if the process proceeds to S74 after S72, the control circuit 230 determines whether the shear member 64 has passed the cutting position 74a (see Figure 7). At this time, the control circuit 230 determines whether the torsion mechanism 30 has started torsion motion based on the detection result of the torsion start detection sensor 142c. This is because the shear member 64 is already beyond the cutting position 74a when the torsion mechanism 30 starts torsion motion (see Figure 17). If the shear member 64 has not passed the cutting position 74a (NO), the process returns to S70. Thus, S70, S72, and S74 are repeated. During this time, the shear member 64 continues to advance along the guide passage 72. As a result, the shear member 64 will eventually pass the cutting position 74a. If the shear member 64 extends beyond the cutting position 74a (YES), the process proceeds to S76.

[0126] In S76, the control circuit 230 stops the torsion motor 76. After S76, the process proceeds to S78.

[0127] In S78, the control circuit 230 drives the torsion motor 76 to rotate in the reverse direction. This causes the torsion mechanism 30 to move towards its initial position. Specifically, the screw shaft 92 rotates in the left-hand thread direction D4, and the outer sleeve 96 retracts. When driving the torsion motor 76, the control circuit 230 performs control (also called constant voltage control) to adjust the voltage applied to the torsion motor 76 to a specific target voltage value. The control circuit 230 also continues to drive the torsion motor 76, which was driven in S78, until it is stopped in S82. After S78, the process proceeds to S80.

[0128] In S80, the control circuit 230 determines whether the torsion mechanism 30 has reached its initial position based on the detection result from the initial position detection sensor 142a. If the torsion mechanism 30 has not reached its initial position (NO), the process repeats S80. While S80 is repeated, the torsion mechanism 30 moves toward its initial position. If the torsion mechanism 30 reaches its initial position (YES), the process proceeds to S82.

[0129] In S82, the control circuit 230 stops the torsion motor 76. After S82, the cutting trial process ends. Once the cutting trial process is complete, the process proceeds to S90 as shown in Figure 23.

[0130] In S90, the control circuit 230 counts the number of times the disconnection attempt process was executed during the initialization process (i.e., the number of disconnection attempts). After S90, the process proceeds to S92.

[0131] In S92, the control circuit 230 determines whether the disconnection completion flag is set. If the disconnection completion flag is not set (NO), the process proceeds to S94.

[0132] In S94, the control circuit 230 determines whether the number of cutting attempts is equal to or greater than the upper limit (for example, 10 times). If the number of cutting attempts is less than the upper limit (NO), the process proceeds to S100. In S100, the control circuit 230 performs a small-feed process to feed out a small amount of wire W.

[0133] (Small volume feeding process: Figure 28) When the small-volume feed process begins, the process proceeds to S102.

[0134] In S102, the control circuit 230 drives the feed motor 32 to rotate in the forward direction. This causes the feed mechanism 24 to start the feed motion. When driving the feed motor 32, the control circuit 230 performs control (also called constant voltage control) to adjust the voltage applied to the feed motor 32 to a specific target voltage value. The control circuit 230 also continues to drive the feed motor 32, which was driven in S102, until it is stopped in S106. After S102, the process proceeds to S104.

[0135] In S104, the control circuit 230 determines, based on the detection result from the rotation detection board 33, whether the number of rotations of the feed motor 32 since starting the feed motor 32 has reached or exceeded the first target number of rotations. The amount of wire W fed by the small-volume feed process is proportional to the number of rotations of the feed motor 32. The first target number of rotations used in S104 is set so that the amount of wire W fed by the small-volume feed process is small. Here, "small" means, for example, an amount of feed smaller than the distance from the position between the first gear 44 and the second gear 46 (see Figure 6) to the cutting position 74a (see Figure 7). If the number of rotations of the feed motor 32 is less than the first target number of rotations (NO), the process repeats S104. While S104 is repeated, the feed motion by the feed mechanism 24 continues, and the wire W is fed. If the number of rotations of the feed motor 32 is greater than or equal to the first target number of rotations (YES), the process proceeds to S106.

[0136] In S106, the control circuit 230 stops the feed motor 32. After S106, the small-volume feed process ends. Once the small-volume feed process is complete, the process returns to S60 as shown in Figure 23.

[0137] Normally, the cutting trial process and the small-quantity feed process are repeatedly executed, causing the cutting mechanism 28 to cut the wire W, thereby aligning the tip of the wire W to the cutting position 74a (see Figure 7). When the cutting mechanism 28 cuts the wire W, the cutting completion flag is set, so the subsequent S92 is judged as YES, and the initialization process ends.

[0138] However, the number of cutting attempts may increase without the wire W being cut. For example, this may occur if the wire W is not properly set in the feeding mechanism 24. In this case, S94 determines that the number of cutting attempts is greater than or equal to the upper limit (YES), and the process proceeds to S96. In S96, the control circuit 230 performs error processing. During error processing, the control circuit 230 displays the error details (for example, that the wire W is not properly set in the feeding mechanism 24) on the display unit 4c. The control circuit 230 also disables the driving of the feeding motor 32 and the torsion motor 76. Error processing continues, for example, until the power to the rebar tying machine 2 is turned off.

[0139] (Regarding parameter changes for small-volume feeding processing) The control circuit 230 changes the target voltage value for constant voltage control in the small-volume feed process (see Figure 28) according to the type of wire W identified in the wire type identification process of the main process (see Figure 21). Specifically, the control circuit 230 sets the target voltage value for annealed wire (i.e., medium-hardness wire W) lower than the target voltage value set for stainless steel wire (i.e., high-hardness wire W). Also, it sets the target voltage value for poly-coated wire (i.e., low-hardness wire W) lower than the target voltage value set for annealed wire (i.e., medium-hardness wire W). The lower the hardness of the wire W, the more likely it is to be damaged when fed to the feed mechanism 24. Poly-coated wire (i.e., wire W with a coating) is at risk of the coating peeling off. For this reason, when low-hardness wire W is used, the target voltage value is lowered to prevent damage to the surface of the wire W. When a wire W with a coating is used, the target voltage value is lowered and the rotation speed of the feed motor 32 is lowered to suppress the peeling of the coating. On the other hand, when a high-hardness wire W is used, the target voltage value is increased and the rotation speed of the feed motor 32 is increased to quickly feed out the wire W.

[0140] Furthermore, the control circuit 230 changes the first target number of rotations in the small-volume feed process depending on the type of wire W. Specifically, the control circuit 230 sets the first target number of rotations for polycoated wire (i.e., wire W with a coating) to be higher than the first target number of rotations set for annealed wire and stainless steel wire (i.e., wire W without a coating). Since wire W with a coating tends to be more slippery than wire W without a coating, the amount fed by the feed mechanism 24 may be less than the desired amount. For this reason, when wire W with a coating is used, the first target number of rotations is increased to adjust the amount fed to the desired amount.

[0141] (Binding process: Figure 29) The bundling process is performed in S24 of the main process (see Figure 21).

[0142] In the tying process, the control circuit 230 sequentially executes the following: feeding process, end gripping process, pull-back process, cutting and twisting process, and initial position return process. The feeding process is the process of rotating the feed motor 32 forward to cause the rebar tying machine 2 to perform a feeding motion. The end gripping process is the process of rotating the twist motor 76 forward to cause the rebar tying machine 2 to perform an end gripping motion. The pull-back process is the process of rotating the feed motor 32 in reverse to cause the rebar tying machine 2 to perform a pull-back motion. The cutting and twisting process is the process of rotating the twist motor 76 forward to cause the rebar tying machine 2 to perform a cutting motion and a twisting motion. The initial position return process is the process of rotating the twist motor 76 in reverse to cause the rebar tying machine 2 to perform an initial position return motion.

[0143] (Feedback process: Figure 30) In S122, the control circuit 230 drives the feed motor 32 to rotate in the forward direction. This causes the feed mechanism 24 to begin its feed motion. When driving the feed motor 32, the control circuit 230 performs control (also called constant voltage control) to adjust the voltage applied to the feed motor 32 to a specific target voltage value. The control circuit 230 also continues to drive the feed motor 32, which was driven in S122, until it is stopped in S126. After S122, the process proceeds to S124.

[0144] In S124, the control circuit 230 determines, based on the detection result from the rotation detection board 33, whether the number of rotations of the feed motor 32 since starting the feed motor 32 has reached or exceeded the second target number of rotations. The amount of wire W fed by the feed process is proportional to the number of rotations of the feed motor 32. The second target number of rotations used in S124 is set, for example, so that the amount of wire W fed by the feed process is approximately 320 mm. If the number of rotations of the feed motor 32 is less than the second target number of rotations (NO), the process repeats S124. While S124 is repeated, the feed motion by the feed mechanism 24 continues, and the wire W is wound around the reinforcing bar R in a circular pattern. If the number of rotations of the feed motor 32 reaches or exceeds the second target number of rotations (YES), the process proceeds to S126.

[0145] In S126, the control circuit 230 stops the feed motor 32. After S126, the feed process ends.

[0146] (Regarding parameter changes related to the sending process) The control circuit 230 changes the target voltage value for constant voltage control in the feeding process according to the type of wire W identified in the wire type identification process of the main process (see Figure 21). Specifically, the control circuit 230 sets the target voltage value for annealed wire (i.e., medium-hardness wire W) lower than the target voltage value set for stainless steel wire (i.e., high-hardness wire W). Also, the target voltage value set for poly-coated wire (i.e., low-hardness wire W) is lower than the target voltage value set for annealed wire (i.e., medium-hardness wire W). The lower the hardness of the wire W, the more likely it is to be damaged when fed to the feeding mechanism 24. Poly-coated wire (i.e., wire W with a coating) is at risk of the coating peeling off. Therefore, when low-hardness wire W is used, the target voltage value is lowered to prevent damage to the surface of the wire W. When wire W with a coating is used, the target voltage value is lowered and the rotation speed of the feeding motor 32 is lowered to suppress peeling of the coating. On the other hand, when a high-hardness wire W is used, the target voltage value is increased and the rotational speed of the feed motor 32 is increased to quickly feed out the wire W.

[0147] Furthermore, the control circuit 230 changes the second target number of rotations during the feeding process depending on the type of wire W. Specifically, the control circuit 230 sets a second target number of rotations for polycoated wire (i.e., wire W with a coating) to be higher than the second target number of rotations set for annealed wire and stainless steel wire (i.e., wire W without a coating). Since wire W with a coating tends to be more slippery than wire W without a coating, the amount fed by the feeding mechanism 24 may be less than the desired amount. For this reason, when wire W with a coating is used, the second target number of rotations is increased to adjust the amount fed to the desired amount.

[0148] (Tip gripping process: Figure 31) In S132, the control circuit 230 drives the torsion motor 76 to rotate in the forward direction. As a result, the screw shaft 92 rotates in the right-hand thread direction D3 from the initial position of the torsion mechanism 30, and the outer sleeve 96 moves forward. When driving the torsion motor 76, the control circuit 230 performs control (also called constant voltage control) to adjust the voltage value applied to the torsion motor 76 to a specific target voltage value. The control circuit 230 also continues to drive the torsion motor 76, which was driven in S132, until it is stopped in S144. After S132, the process proceeds to S134.

[0149] In S134, the control circuit 230 determines whether the elapsed time since starting the torsion motor 76 in S132 (i.e., the driving time of the torsion motor 76) exceeds the current mask time Tm. If the driving time of the torsion motor 76 is less than or equal to the current mask time Tm (NO), the process repeats S134. The current mask time Tm is the time to wait until the starting current flowing through the torsion motor 76 exceeds its peak. If the driving time of the torsion motor 76 exceeds the current mask time Tm (YES), i.e., if the starting current flowing through the torsion motor 76 exceeds its peak, the process proceeds to S136.

[0150] In S136, the control circuit 230 sets a reference value Ir to be used in subsequent processing. For example, the control circuit 230 sets the torsion motor current value I at the point when the driving time of the torsion motor 76 exceeds the current mask time Tm as the reference value Ir. After S136, the process proceeds to S138.

[0151] In S138, the control circuit 230 determines whether the current torsion motor current value I is less than the set reference value Ir. If the current torsion motor current value I is less than the reference value Ir (YES), the process proceeds to S140.

[0152] In S140, the control circuit 230 sets the current torsion motor current value I as the new reference value Ir. That is, the control circuit 230 updates the reference value Ir. In subsequent processing, the control circuit 230 refers to the updated reference value Ir.

[0153] If the current torsion motor current value I is greater than or equal to the reference value Ir in S138 (NO), or if after S140, the process proceeds to S142. In S142, the control circuit 230 determines whether the torsion mechanism 30 has reached the tip gripping position based on the detection result of the tip gripping position detection sensor 142b. If the torsion mechanism 30 has not reached the tip gripping position (NO), the process returns to S138. If the torsion mechanism 30 has reached the tip gripping position (YES), the process proceeds to S144.

[0154] In S144, the control circuit 230 stops the torsion motor 76. After S144, the tip gripping process is completed.

[0155] (Retraction process: Figure 32) In S152, the control circuit 230 drives the feed motor 32 to rotate in the reverse direction. This causes the feed mechanism 24 to begin a pull-back motion. When driving the feed motor 32, the control circuit 230 performs control (also called constant current control) to make the current flowing through the feed motor 32 follow a specific target current value. The control circuit 230 also continues to drive the feed motor 32, which was driven in S152, until it is stopped in S158. After S152, the process proceeds to S154.

[0156] In S154, the control circuit 230 determines, based on the detection result from the rotation detection board 33, whether the number of rotations of the feed motor 32 since starting the feed motor 32 has exceeded the upper limit number of rotations. If the number of rotations of the feed motor 32 is less than the upper limit number of rotations (NO), the process proceeds to S156.

[0157] In S156, the control circuit 230 determines, based on the detection result from the rotation detection board 33, whether the rotation speed of the feed motor 32 has fallen below the pull-back completion speed. As the wire W is pulled back, if the wire W comes into close contact with the reinforcing bar R, the feed mechanism 24 can no longer pull the wire W back any further. In this case, the load on the feed motor 32 via the feed mechanism 24 increases. During the pull-back process, the control circuit 230 performs constant current control, so the rotation speed of the feed motor 32 decreases as the load on the feed motor 32 increases. Therefore, in S156, it can be said that the control circuit 230 is determining whether the wire W has come into close contact with the reinforcing bar R. If the rotation speed of the feed motor 32 is above the pull-back completion speed (NO), that is, if the wire W is not in close contact with the reinforcing bar R, the process returns to S154.

[0158] If, in S154, the number of rotations of the feed motor 32 is equal to or greater than the upper limit (YES), the process proceeds to S158. Alternatively, if, in S156, the rotation speed of the feed motor 32 is equal to or less than the pull-back termination speed (YES), that is, if the wire W is in close contact with the reinforcing bar R, the process proceeds to S158. In S158, the control circuit 230 stops the feed motor 32. After S158, the pull-back process is completed.

[0159] (Regarding parameter changes related to the pullback process) The control circuit 230 changes the target current value (i.e., the torque of the feed motor 32) and the return termination speed for constant current control during the return process, according to the type of wire W identified in the wire type identification process of the main process (see Figure 21). Specifically, the control circuit 230 sets the target current value for polycoated wire (i.e., wire W with a coating) lower than the target current value set for annealed wire and stainless steel wire (i.e., wire W without a coating). Also, the control circuit 230 sets the return termination speed for polycoated wire (i.e., wire W with a coating) higher than the return termination speed set for annealed wire and stainless steel wire (i.e., wire W without a coating). Since wire W with a coating tends to slip more easily than wire W without a coating, if the torque of the feed motor 32 is too high, slippage may occur between the feed mechanism 24 and the wire W, and it may take time for the rotational speed of the feed motor 32 to fall below the return termination speed. This may cause the pull-back process to take a long time to complete. Therefore, when a wire W with a coating is used, the target current value is lowered to suppress slippage between the feed mechanism 24 and the wire W. In addition, the pull-back completion speed is increased to stop the feed motor 32 earlier. This allows the pull-back process to be completed quickly.

[0160] (Cutting and twisting process: Figure 33) In S172, the control circuit 230 drives the torsion motor 76 to rotate in the forward direction. As a result, the screw shaft 92 rotates in the right-hand thread direction D3 from the state in which the torsion mechanism 30 is in the tip gripping position, and the outer sleeve 96 moves forward. When driving the torsion motor 76, the control circuit 230 performs control (also called constant voltage control) to adjust the voltage value applied to the torsion motor 76 to a specific target voltage value. The control circuit 230 also continues to drive the torsion motor 76, which was driven in S172, until it is stopped in S190. After S172, the process proceeds to S174.

[0161] In S174, the control circuit 230 determines whether the torsion mechanism 30 has started torsion motion based on the detection result of the torsion start detection sensor 142c. If the torsion mechanism 30 has not started torsion motion (NO), the process repeats S174. While S174 is repeated, the torsion mechanism 30 moves toward the position where it will start torsion motion. If the torsion mechanism 30 starts torsion motion (YES), the process proceeds to S176.

[0162] In S176, the control circuit 230 starts counting the number of rotations of the torsion motor 76 based on the detection result from the rotation detection board 78. This counts the number of rotations of the torsion motor 76 since the torsion mechanism 30 started its torsional motion. After S176, the process proceeds to S178.

[0163] In S178, the control circuit 230 determines whether the number of rotations of the torsion motor 76 since the torsion mechanism 30 started its torsion motion has exceeded the minimum number of rotations. If the number of rotations of the feed motor 32 is less than the minimum number of rotations (NO), the process repeats S176. By repeating S176, the torsion mechanism 30 continues its torsion motion to the minimum extent required. If the number of rotations of the feed motor 32 is equal to or greater than the minimum number of rotations (YES), the process proceeds to S180.

[0164] In S180, the control circuit 230 calculates the current difference value ΔI to be used in subsequent processing. The control circuit 230 calculates the current difference value ΔI by subtracting the reference value Ir set in the tip gripping process (see Figure 31) from the current torsion motor current value I. After S180, the process proceeds to S182.

[0165] In S182, the control circuit 230 determines whether the current difference value ΔI calculated in S180 is greater than or equal to the first difference threshold Id1. The first difference threshold Id1 is set according to the binding force setting value that the user has set in advance. The higher the binding force setting value, the larger the first difference threshold Id1 is set to. The lower the binding force setting value, the smaller the first difference threshold Id1 is set to. As the twisting mechanism 30 twists the wire W, the torsional torque of the wire W increases, and therefore the load on the twisting motor 76 via the twisting mechanism 30 increases. In this case, since the control circuit 230 is controlling the twisting motor 76 with a constant voltage, as the load on the twisting motor 76 increases, the twisting motor current value I, and consequently the current difference value ΔI, increases. As a result of the increase in the current difference value ΔI, if the current difference value ΔI becomes greater than or equal to the first difference threshold Id1, S182 determines YES, and the process proceeds to S190. In S190, the control circuit 230 stops the torsion motor 76. This ends the torsion motion when the torsion torque of the wire W reaches a certain level. The first difference threshold Id1 is set so that the torsion torque at the point when the current difference value ΔI reaches the first difference threshold Id1 (i.e., when the torsion motion ends) is of a desired magnitude according to the set value of the binding force. This adjusts the torsion torque of the wire W when the torsion motion ends (i.e., the torsion completion torque) to a desired magnitude according to the set value of the binding force. In S182, the control circuit 230 can also be said to be determining whether or not the torsion torque of the wire W has reached the desired magnitude.

[0166] If the current difference value ΔI in S182 is less than the first difference threshold Id1 (i.e., NO), the process proceeds to S184. In S184, the control circuit 230 determines whether the current difference value ΔI calculated in S180 is greater than or equal to the second difference threshold Id2, which is smaller than the first difference threshold Id1. The second difference threshold Id2 is set according to the binding force setting value that the user has set in advance, similar to the first difference threshold Id1. The second difference threshold Id2 is set so that the torsional torque at the point when the current difference value ΔI reaches the second difference threshold Id2 is not the desired magnitude, but is of a certain magnitude.

[0167] If the current difference value ΔI in S184 is greater than or equal to the second difference threshold Id2 (YES), the process proceeds to S186. In S186, the control circuit 230 monitors the time rate of change dI / dt of the torsion motor current value I and determines whether the time rate of change dI / dt has changed from positive to negative. As the torsion mechanism 30 twists the wire W, the wire W may come to the brink of breaking. Just before the wire W breaks, the tension of the wire W decreases, and the load on the torsion motor 76 decreases. In this case, since the control circuit 230 controls the torsion motor 76 with a constant voltage, the torsion motor current value I, and consequently the current difference value ΔI, decreases as the load on the torsion motor 76 decreases. As the current difference value ΔI decreases, the time rate of change dI / dt changes from positive to negative, so in S186 it is determined to be YES and the process proceeds to S190. In S190, the control circuit 230 stops the torsion motor 76. As a result, the torsion motion ends just before the wire W is about to break, thus preventing the wire W from breaking. In S184, it can be said that the control circuit 230 is determining whether or not the wire W is about to break.

[0168] If, in S184, the current difference value ΔI is less than the second difference threshold Id2 (NO), or if, in S186, the time rate of change dI / dt has not changed from positive to negative (NO), the process proceeds to S188. In S188, the control circuit 230 determines whether the number of rotations of the torsion motor 76 since the torsion mechanism 30 started the torsion motion has exceeded the upper limit. If the number of rotations of the feed motor 32 is less than the upper limit (NO), the process returns to S180. If the number of rotations of the feed motor 32 is greater than or equal to the upper limit (YES), the process proceeds to S190. In S190, the control circuit 230 stops the torsion motor 76. This ends the torsion motion.

[0169] After S190, the cutting and twisting processes are completed.

[0170] (Regarding parameter changes for cutting and twisting processes) The control circuit 230 changes the first differential threshold Id1 and the second differential threshold Id2 according to the type of wire W identified in the wire type identification process of the main process (see Figure 21). Specifically, the control circuit 230 sets the differential thresholds Id1 and Id2 set for stainless steel wire (i.e., high-strength wire W) higher than the differential thresholds Id1 and Id2 set for annealed wire and poly-coated wire (i.e., low-strength wire W). When twisting high-strength wire W, high output is required from the torsion motor 76. However, if the torsion motor 76 is required to exert high output even when twisting low-strength wire W, there is a risk that the wire W will break. Therefore, when high-strength wire W is used, the differential thresholds Id1 and Id2 are increased to allow the torsion motor 76 to exert high output. On the other hand, when a low-strength wire W is used, the differential thresholds Id1 and Id2 are lowered to prevent the torsion motor 76 from exhibiting high output. This suppresses the wire W from twisting and breaking.

[0171] (Return to initial position process) In the initial position return process, the control circuit 230 drives the torsion motor 76 to rotate in the reverse direction, thereby returning the torsion mechanism 30 to its initial position. Note that the initial position return process in the binding process is the same as the initial position return process described above (see Figure 24) as part of the initialization process (see Figure 23), so please refer to Figure 24 for details.

[0172] (Advantages of bundling) As shown in Figures 34 and 35, the torsion motor current value I may differ when performing the same process depending on the temperature of the environment in which the rebar tying machine 2 is used. This is because, depending on the temperature of the environment in which the rebar tying machine 2 is used, for example, the viscosity of the lubricant added to the torsion mechanism 30 and the torsion motor 76 changes, which in turn changes the amount of loss in the torsion mechanism 30 and the torsion motor 76. For example, in a low temperature environment (-20°C), the amount of loss in the torsion mechanism 30 and the torsion motor 76 increases compared to a room temperature environment (e.g., 27°C), and the torsion motor current value I increases. Therefore, if the torsion motion is stopped in response to the increase in the torsion motor current value I after the start of the torsion motion, the torsion completion torque may be smaller in a low temperature environment compared to a room temperature environment.

[0173] Therefore, in the binding process of this embodiment, a reference value Ir is set as an indicator of the magnitude of the loss in the torsion mechanism 30 and the torsion motor 76, and the reference value Ir is reflected in the conditions for stopping the torsional motion (i.e., the torsion stop conditions). The torsion stop conditions referred to here are the judgment conditions of S182 shown in Figure 33.

[0174] As shown in Figure 34, the reference value Ir is the minimum value of the torsion motor current I during the period after the current mask time Tm has elapsed since the torsion motor 76 was started in the tip gripping process (see Figure 31) (i.e., the period after the peak of the starting current of the torsion motor 76 has been exceeded). The reference value Ir in a low-temperature environment is larger than the reference value Ir in a room-temperature environment. This is because the losses in the torsion mechanism 30 and the torsion motor 76 are greater in a low-temperature environment compared to a room-temperature environment.

[0175] As shown in Figure 35, in this embodiment, after the start of the torsional motion, the torsional stop condition is met when the difference ΔI between the torsional motor current value I and the reference value Ir reaches the first difference threshold Id1. After that, the torsional motor 76 stops, and the torsional motion stops. For this reason, in a low-temperature environment, the torsional motion continues until the torsional motor current value I becomes significantly larger than in a room-temperature environment. As a result, the increase in losses in a low-temperature environment is offset, and the torsional completion torque becomes the same as in a room-temperature environment. This makes it possible to suppress fluctuations in the torsional completion torque depending on the temperature of the environment in which the rebar tying machine 2 is used. In other words, it is possible to suppress fluctuations in the torsional completion torque depending on changes in the amount of losses in the torsional mechanism 30 and the torsional motor 76.

[0176] In this embodiment, there is also a separate torsion stop condition, which is the judgment condition S184 shown in Figure 33. This torsion stop condition is also set based on the reference value Ir.

[0177] (Example 2) The rebar tying machine 2 of this embodiment differs from the rebar tying machine 2 of Embodiment 1 in that the control circuit 230 sets the reference value Ir based on the feed motor current value I' instead of the torsion motor current value I. Specifically, the rebar tying machine 2 of this embodiment differs from the rebar tying machine 2 of Embodiment 1 in that the control circuit 230 performs the feed process shown in Figure 36 instead of the feed process shown in Figure 30, and the tip gripping process shown in Figure 37 instead of the tip gripping process shown in Figure 31. These differences will be explained below.

[0178] (Feedback process: Figure 36) In S202, the control circuit 230 drives the feed motor 32 to rotate in the forward direction. This causes the feed mechanism 24 to begin its feed motion. When driving the feed motor 32, the control circuit 230 performs control (also called constant voltage control) to adjust the voltage applied to the feed motor 32 to a specific target voltage value. The control circuit 230 also continues to drive the feed motor 32, which was driven in S202, until it is stopped in S214. After S202, the process proceeds to S204.

[0179] In S204, the control circuit 230 determines whether the elapsed time since starting the feed motor 32 in S202 (i.e., the driving time of the feed motor 32) exceeds the current mask time Tm'. If the driving time of the feed motor 32 is less than or equal to the current mask time Tm' (NO), the process repeats S204. The current mask time Tm' is the time to wait until the starting current flowing to the feed motor 32 exceeds its peak. If the driving time of the feed motor 32 exceeds the current mask time Tm' (YES), i.e., if the starting current flowing to the feed motor 32 exceeds its peak, the process proceeds to S206.

[0180] In S206, the control circuit 230 sets a reference value Ir to be used in the cutting and twisting process (see Figure 33). For example, the control circuit 230 sets the feed motor current value I' at the point when the drive time of the feed motor 32 exceeds the current mask time Tm' as the reference value Ir. After S206, the process proceeds to S208.

[0181] In S208, the control circuit 230 determines whether the current feed motor current value I' is less than the set reference value Ir. If the current feed motor current value I' is less than the reference value Ir (YES), the process proceeds to S210.

[0182] In S210, the control circuit 230 sets the current feed motor current value I' as the new reference value Ir. That is, the control circuit 230 updates the reference value Ir. In subsequent processing, the control circuit 230 refers to the updated reference value Ir.

[0183] If, in S208, the current feed motor current value I' is greater than or equal to the reference value Ir (NO), or after S210, the process proceeds to S212. In S212, the control circuit 230 determines, based on the detection result from the rotation detection board 33, whether the number of rotations of the feed motor 32 since starting the feed motor 32 has reached or exceeded the second target number of rotations (similar to S124 shown in Figure 30). If the number of rotations of the feed motor 32 is less than the second target number of rotations (NO), the process returns to S208. If the number of rotations of the feed motor 32 is greater than or equal to the second target number of rotations (YES), the process proceeds to S214.

[0184] In S214, the control circuit 230 stops the feed motor 32. After S214, the feed process shown in Figure 36 is completed.

[0185] (Tip gripping process: Figure 37) In S222, the control circuit 230 drives the torsion motor 76 to rotate in the forward direction. As a result, the screw shaft 92 rotates in the right-hand thread direction D3 from the initial position of the torsion mechanism 30, and the outer sleeve 96 moves forward. When driving the torsion motor 76, the control circuit 230 performs control (also called constant voltage control) to adjust the voltage value applied to the torsion motor 76 to a specific target voltage value. The control circuit 230 also continues to drive the torsion motor 76, which was driven in S222, until it is stopped in S226. After S222, the process proceeds to S224.

[0186] In S224, the control circuit 230 determines whether the twisting mechanism 30 has reached the tip gripping position based on the detection result of the tip gripping position detection sensor 142b. If the twisting mechanism 30 has not reached the tip gripping position (NO), the process repeats S224. If the twisting mechanism 30 has reached the tip gripping position (YES), the process proceeds to S226.

[0187] In S226, the control circuit 230 stops the torsion motor 76. After S226, the tip gripping process shown in Figure 37 is completed.

[0188] Furthermore, since the load required to operate the torsion mechanism 30 (see Figure 10) and the load required to operate the feed mechanism 24 (see Figure 6) are different, a difference may occur between the reference value Ir set based on the torsion motor current value I, as in Embodiment 1, and the reference value Ir set based on the feed motor current value I', as in this embodiment. This difference may also be reflected in the current difference value ΔI calculated in S180 of the cutting and torsion process shown in Figure 33. Therefore, the control circuit 230 of this embodiment may add a predetermined correction value to the current difference value ΔI calculated in S180 of the cutting and torsion process in order to compensate for this difference. For example, if the load required to operate the feed mechanism 24 is considered to be smaller than the load required to operate the torsion mechanism 30, then the feed motor current value I' is considered to be smaller than the torsion motor current value I. In this case, the current difference value ΔI based on the feed motor current value I' is considered to be larger than the current difference value ΔI based on the torsion motor current value I. Therefore, a negative correction value may be added to the current difference value ΔI in this embodiment (i.e., the current difference value ΔI based on the feed motor current value I') to bridge the gap with the current difference value ΔI in Embodiment 1 (i.e., the current difference value ΔI based on the torsion motor current value I). On the other hand, if the load required to move the feed mechanism 24 is considered to be larger than the load required to move the torsion mechanism 30, a positive correction value may be added to the current difference value ΔI in this embodiment. Alternatively, the control circuit 230 may correct the reference value Ir instead of correcting the current difference value ΔI, or it may correct the difference threshold values ​​Id1 and Id2 used in the cutting and torsion processes S182 and S184.

[0189] (Example 3) The rebar tying machine 2 of this embodiment differs from the rebar tying machine 2 of Embodiment 1 in that the control circuit 230 monitors the torsion motor current value I instead of the current difference value ΔI, which is the value obtained by subtracting a reference value Ir from the torsion motor current value I, in order to stop the torsion motion. Specifically, the rebar tying machine 2 of this embodiment differs from the rebar tying machine 2 of Embodiment 1 in that the control circuit 230 performs the cutting and twisting process shown in Figure 38 instead of the cutting and twisting process shown in Figure 33. Note that the cutting and twisting process shown in Figure 38 is the same as the cutting and twisting process shown in Figure 33, with S180, S182, and S184 replaced by S280, S282, and S284. Other processes in the cutting and twisting process shown in Figure 38 are the same as those in the cutting and twisting process shown in Figure 33, so they are denoted by the same reference numerals and their explanations are omitted.

[0190] (Cutting and twisting process: Figure 38) If the number of rotations of the feed motor 32 in S178 is equal to or greater than the lower limit (YES), or if the number of rotations of the feed motor 32 in S188 is less than the upper limit (NO), the process proceeds to S280.

[0191] In S280, the control circuit 230 sets a first current threshold Ic1 and a second current threshold Ic2 to be used in subsequent processing, based on the reference value Ir set in the tip gripping process (see Figure 31) and the binding force setting value set in advance by the user. The second current threshold Ic2 is set to a value smaller than the first current threshold Ic1. For example, each of the first current threshold Ic1 and the second current threshold Ic2 may be set to a value obtained by adding a correction value according to the binding force setting value to the reference value Ir. This correction value may be set to a larger value as the binding force setting value increases. Alternatively, each of the first current threshold Ic1 and the second current threshold Ic2 may be set to a value that discretely increases or decreases in response to an increase or decrease in the reference value Ir, plus a correction value according to the binding force setting value. In this way, each of the first current threshold Ic1 and the second current threshold Ic2 is set to a larger value as the reference value Ir increases, provided that the binding force setting value is the same. After S280, the process proceeds to S282.

[0192] In S282, the control circuit 230 determines whether the current torsion motor current value I is greater than or equal to the first current threshold Ic1 set in S280. As the torsion mechanism 30 twists the wire W, the torsional torque of the wire W increases, and the load on the torsion motor 76 via the torsion mechanism 30 increases. In this case, since the control circuit 230 is controlling the torsion motor 76 with a constant voltage, the torsion motor current value I increases as the load on the torsion motor 76 increases. As a result, when the torsion motor current value I becomes greater than or equal to the first current threshold Ic1, S282 determines YES, and the process proceeds to S190. In S190, the control circuit 230 stops the torsion motor 76. This ends the torsion motion when the torsional torque of the wire W has grown to a certain extent. As a result, the torsional torque of the wire W when the twisting motion is completed (i.e., the twisting completion torque) is adjusted to a desired size according to the set value of the binding force. In S282, it can also be said that the control circuit 230 is determining whether or not the torsional torque of the wire W has reached the desired size.

[0193] If the torsion motor current value I is less than the first current threshold Ic1 in S282 (NO), the process proceeds to S284. In S284, the control circuit 230 determines whether the current torsion motor current value I is greater than or equal to the second current threshold Ic2 set in S280. If the torsion motor current value I is greater than or equal to the second current threshold Ic2 (YES), the process proceeds to S186. If the torsion motor current value I is less than the second current threshold Ic2 (NO), the process proceeds to S188.

[0194] In this embodiment as well, as described in Embodiment 2, the control circuit 230 may set the reference value Ir based on the feed motor current value I' instead of setting the reference value Ir based on the torsion motor current value I.

[0195] (modified version) The rebar tying machine 2 may also be used as a tying machine for tying objects other than rebars R (for example, metal pipes).

[0196] (See Figure 31) The control circuit 230 does not need to reset the reference value Ir each time it performs the tip gripping process. For example, the control circuit 230 may perform the process of setting the reference value Ir (S136, S138, S140) only in the first tip gripping process performed after the power of the rebar tying machine 2 is turned on.

[0197] (See Figures 23-25) Instead of setting the torsion motor current value I detected during the execution of the tip gripping process (i.e., the period from the start of the binding operation until the start of the twisting motion) as the reference value Ir, the control circuit 230 may set the torsion motor current value I detected during the execution of the initial position return process in the initialization process (i.e., S50) as the reference value Ir. Alternatively, the control circuit 230 may set the torsion motor current value I detected during the period in which steps S66 and S68 of the cutting trial process are repeated as the reference value Ir. Alternatively, the control circuit 230 may drive the torsion motor 76 extra between steps S74 and S76 of the cutting trial process and set the torsion motor current value I detected during that time as the reference value Ir. Alternatively, the control circuit 230 may set the torsion motor current value I detected during the period in which S80 is repeated in the cutting trial process (i.e., the period in which the torsion mechanism 30 is moving toward the initial position) as the reference value Ir.

[0198] (See Figure 29) Instead of setting the torsion motor current value I detected during the execution of the tip gripping process (i.e., the period from when the binding operation is started until the twisting motion starts) as the reference value Ir, the control circuit 230 may set the torsion motor current value I detected during the execution of the initial position return process in the binding process (i.e., the period from when the twisting motion stops until the binding operation is finished) as the reference value Ir.

[0199] (See Figure 33) Instead of setting the torsion motor current value I detected during the execution of the tip gripping process (i.e., the period when the torsion mechanism 30 is not holding the wire W) as the reference value Ir, the control circuit 230 may set the torsion motor current value I detected during the period when S174 is repeated in the cutting and torsion process (i.e., the period when the torsion mechanism 30 is in contact with the wire W) as the reference value Ir.

[0200] (See Figure 33) The control circuit 230 may set or change the torsion stop conditions based on the state of the torsion motor 76 other than the current value flowing through the torsion motor 76. For example, the rebar tying machine 2 may further include a temperature sensor for detecting the temperature of the torsion motor 76. The control circuit 230 may set or change the torsion stop conditions based on the temperature of the torsion motor 76 detected by the temperature sensor. For example, the control circuit 230 may change the first differential threshold Id1 and the second differential threshold Id2 according to the temperature of the torsion motor 76. In this case, the temperature of the torsion motor 76 referenced by the control circuit 230 is not limited to the temperature detected during the period when the torsion motor 76 is running, but may also be the temperature detected during the period when the torsion motor 76 is stopped. In yet another example, the temperature sensor may be attached to a machine part to which lubricant is applied, rather than to the torsion motor 76. In this case, the temperature sensor may detect the temperature of the lubricant.

[0201] (See Figure 33) The control circuit 230 may change the decision condition in S188 based on the reference value Ir. For example, the upper limit of rotational speed used in S188 may be increased when the reference value Ir is high, and the upper limit of rotational speed may be decreased when the reference value Ir is low.

[0202] (See Figure 22) The wire type detection unit 214 may also be capable of detecting wires W other than the three types of wires W described in the embodiment (for example, galvanized wires W).

[0203] The control circuit 230 may classify the wires W based on characteristics other than strength, hardness, and the presence or absence of coating material (e.g., coefficient of friction).

[0204] (See Figure 21) The control circuit 230 may change the voltage thresholds V1 and V2 according to characteristics other than strength (e.g., hardness). For example, the voltage thresholds V1 and V2 set for a high-hardness wire W may be higher than the voltage thresholds V1 and V2 set for a low-hardness wire W.

[0205] (See Figures 28 and 30) The control circuit 230 may change the target voltage value of the feed motor 32 during small-volume feeding and feeding processes according to characteristics other than hardness (e.g., strength). For example, the target voltage value set for low-strength wire W may be lower than the target rotational speed set for high-strength wire W.

[0206] (See Figure 28) The control circuit 230 may change the first target number of rotations in the small-volume feed process according to characteristics other than the presence or absence of coating material (for example, the friction coefficient of the wire W). For example, the first target number of rotations set for a wire W with a low friction coefficient may be greater than the first target number of rotations set for a wire W with a high friction coefficient.

[0207] (See Figure 30) The control circuit 230 may change the second target number of rotations in the feeding process according to characteristics other than the presence or absence of coating material (for example, the friction coefficient of the wire W). For example, the second target number of rotations set for a wire W with a low friction coefficient may be greater than the second target number of rotations set for a wire W with a high friction coefficient.

[0208] (See Figure 23) The control circuit 230 may perform a small-quantity feed process after the start of the initialization process but before performing the cutting trial process.

[0209] (See Figure 28) The amount of wire W fed by the small-feed process does not have to be small. That is, the amount fed may be greater than the distance from the position between the first gear 44 and the second gear 46 (see Figure 6) to the cutting position 74a (see Figure 7).

[0210] (See Figure 25) The control circuit 230 may determine in the cutting trial process S70 that the cutting mechanism 28 has cut the wire W (i.e., YES) when the current value flowing to the torsion motor 76 (i.e., torsion motor current value I) exceeds the current threshold Ith.

[0211] (See Figure 25) The control circuit 230 may determine whether the cutting mechanism 28 has cut the wire W in S70 of the cutting trial process without referring to the torsion motor current value I. For example, the rebar tying machine 2 may be equipped with a piece detection sensor (e.g., an image sensor) that detects the piece generated when the wire W is cut by the cutting mechanism 28. The control circuit 230 may determine whether the cutting mechanism 28 has cut the wire W based on the detection result from the piece detection sensor.

[0212] (See Figure 25) The control circuit 230 may switch the rotation direction of the torsion motor 76 from forward rotation to reverse rotation in steps S74, S76, and S78 of the cutting trial process, without relying on the detection result from the torsion start detection sensor 142c. For example, the control circuit 230 may switch the rotation direction of the torsion motor 76 from forward rotation to reverse rotation if the number of rotations of the torsion motor 76 since it was started in step S62 exceeds a predetermined number.

[0213] (Features of the example) In one or more embodiments, a rebar tying machine 2 (example of a tying machine) ties a rebar R (example of an object to be tied) using a wire W. The rebar tying machine 2 includes a feed mechanism 24 capable of performing a feed motion to feed the wire W around the rebar R, a feed motor 32 for operating the feed mechanism 24, a twisting mechanism 30 capable of performing a twisting motion to twist the wire W around the rebar R, a twisting motor 76 for operating the twisting mechanism 30, a battery voltage detection circuit 236 (example of a voltage detection unit) for detecting the voltage of a battery pack B (example of a battery) that supplies power to the feed motor 32 and the twisting motor 76, respectively, a wire type detection unit 214 for detecting the type of wire W, and a control circuit 230 (example of a control unit) for controlling the operation of the feed motor 32 and the twisting motor 76, respectively. The control circuit 230 is configured to prohibit the driving of at least one of the feed motor 32 and the torsion motor 76 if the voltage value of the battery pack B detected by the battery voltage detection circuit 236 is less than or equal to a specific first voltage threshold V1 (or second voltage threshold V2). The control circuit 230 is configured to change the first voltage threshold V1 (or second voltage threshold V2) depending on the type of wire W detected by the wire type detection unit 214.

[0214] When the voltage of battery pack B drops, the voltage input to the feed motor 32 and the torsion motor 76 may be insufficient, preventing them from being driven at the desired output. If the feed motor 32 is driven in this case to start the feed motion of the feed mechanism 24, the feed motion may be terminated prematurely. Similarly, if the torsion motor 76 is driven to start the torsion motion of the torsion mechanism 30, the torsion motion may be terminated prematurely. With the above configuration, if the voltage of battery pack B falls below a specific first voltage threshold V1 (or second voltage threshold V2) (i.e., when the voltage of battery pack B drops), driving of at least one of the feed motor 32 and the torsion motor 76 is prohibited. This prevents each motion from being terminated prematurely. However, the output that each motor must exert to complete each motion varies depending on the type of wire W used for bundling. For example, when using a high-strength wire W, the output that each motor must exert to complete each motion is higher than when using a low-strength wire W. Therefore, if a constant first voltage threshold V1 (or second voltage threshold V2) is used regardless of the type of wire W, while each motion may not be partially completed when using a certain wire W, it is possible that each motion may be partially completed when using a different wire W. Furthermore, with the above configuration, the first voltage threshold V1 (or second voltage threshold V2) can be changed depending on the type of wire W used. This allows setting the first voltage threshold V1 (or second voltage threshold V2) so that each motion is not partially completed depending on the type of wire W. For example, when using a high-strength wire W, the first voltage threshold V1 (or second voltage threshold V2) can be set higher, and when using a low-strength wire W, the first voltage threshold V1 (or second voltage threshold V2) can be set lower. As a result, it is possible to suppress the partial completion of each motion regardless of the type of wire W.

[0215] In one or more embodiments, the wire type detection unit 214 is configured to distinguish and detect stainless steel wire (an example of a wire having a first maximum tensile load) and annealed wire (an example of a wire having a second maximum tensile load). The control circuit 230 is configured to change the first voltage threshold V1 (or second voltage threshold V2) depending on whether the wire type detection unit 214 detects stainless steel wire or annealed wire.

[0216] When using a wire W with a high maximum tensile load, the output that each motor must exert to complete each motion is higher compared to when using a wire W with a low maximum tensile load. With the above configuration, the first voltage threshold V1 (or second voltage threshold V2) can be changed depending on whether a wire W with a high maximum tensile load or a wire W with a low maximum tensile load is used. For example, when using a wire W with a high maximum tensile load, the first voltage threshold V1 (or second voltage threshold V2) can be set higher, and when using a wire W with a low maximum tensile load, the first voltage threshold V1 (or second voltage threshold V2) can be set lower. This makes it possible to prevent each motion from ending prematurely, regardless of the maximum tensile load of the wire W.

[0217] In one or more embodiments, the control circuit 230 determines that the maximum tensile load of the wire W is different when the wire type detection unit 214 detects a stainless steel wire compared to when the wire type detection unit 214 detects an annealed wire.

[0218] With the above configuration, the control circuit 230 can identify differences in the maximum tensile load of the wire W, and therefore can perform control that matches the maximum tensile load of the wire W.

[0219] In one or more embodiments, the ratio of the first maximum tensile load (i.e., the maximum tensile load of the stainless steel wire) to the second maximum tensile load (i.e., the maximum tensile load of the annealed wire) is 115% or more.

[0220] With the above configuration, the first maximum tensile load and the second maximum tensile load are clearly different, so the effect of changing the first voltage threshold V1 (or the second voltage threshold V2) between them is significantly demonstrated.

[0221] In one or more embodiments, the wire type detection unit 214 is configured to distinguish and detect stainless steel wire (an example of a wire having a first yield point load) and annealed wire (an example of a wire having a second yield point load). The control circuit 230 is configured to change the first voltage threshold V1 (or second voltage threshold V2) depending on whether the wire type detection unit 214 detects stainless steel wire or annealed wire.

[0222] When using a wire W with a high yield point load, the output that each motor must exert to complete each motion is higher compared to when using a wire W with a low yield point load. With the above configuration, the first voltage threshold V1 (or second voltage threshold V2) can be changed depending on whether a wire W with a high yield point load or a wire W with a low yield point load is used. This makes it possible to prevent each motion from ending prematurely, regardless of the yield point load of the wire W.

[0223] In one or more embodiments, the control circuit 230 determines that the yield point load of the wire W is different when the wire type detection unit 214 detects a stainless steel wire compared to when the wire type detection unit 214 detects an annealed wire.

[0224] With the above configuration, the control circuit 230 can identify differences in the yield point load of the wire W, and therefore can perform control that matches the yield point load of the wire W.

[0225] In one or more embodiments, the ratio of the first yield point load (i.e., the yield point load of stainless steel wire) to the second yield point load (i.e., the yield point load of annealed wire) is 115% or more.

[0226] With the above configuration, the first yield point load and the second yield point load are clearly different, so the effect of changing the first voltage threshold V1 (or the second voltage threshold V2) between them is significantly demonstrated.

[0227] In one or more embodiments, the rebar tying machine 2 ties reinforcing bars R using wire W. The rebar tying machine 2 includes a feed mechanism 24 capable of performing a feed motion to feed the wire W around the reinforcing bars R, a feed motor 32 for operating the feed mechanism 24, a twisting mechanism 30 capable of performing a twisting motion to twist the wire W around the reinforcing bars R, a twisting motor 76 for operating the twisting mechanism 30, a wire type detection unit 214 for detecting the type of wire W, and a control circuit 230 for controlling the operation of the feed motor 32 and the twisting motor 76, respectively. The control circuit 230 is configured to adjust the voltage value applied to the feed motor 32 to a specific target voltage value when driving the feed motor 32 to cause the feed mechanism 24 to perform a feed motion. The control circuit 230 is configured to change the target voltage value depending on the type of wire W detected by the wire type detection unit 214.

[0228] If the voltage applied to the feed motor 32 during the feed motion is high, the rotation speed of the feed motor 32 will increase, which may cause scratches on the surface of the wire W. However, the susceptibility of the wire W surface to scratches varies depending on the type of wire W. For example, low-hardness wire W is more susceptible to scratches than high-hardness wire W. Therefore, if a constant target voltage value is used regardless of the type of wire W, the surface of the wire W may not be scratched when using one type of wire W, but it may be scratched when using another type of wire W. With the above configuration, the target voltage value can be changed according to the type of wire W used. This makes it possible to set a target voltage value that prevents scratches on the surface of the wire W, depending on the type of wire W. For example, the target voltage value can be set lower when using low-hardness wire W, and higher when using high-hardness wire W. As a result, scratches on the surface of the wire W can be suppressed regardless of the type of wire W.

[0229] In one or more embodiments, the wire type detection unit 214 is configured to distinguish and detect stainless steel wire (an example of a wire having a first hardness) and polycoated wire (an example of a wire having a second hardness). The control circuit 230 is configured to change the target voltage value depending on whether the wire type detection unit 214 detects a stainless steel wire or a polycoated wire.

[0230] Low-hardness wire W is more susceptible to surface scratches compared to high-hardness wire W. With the above configuration, the target voltage value can be changed depending on whether low-hardness wire W or high-hardness wire W is used. For example, the target voltage value can be set lower when using low-hardness wire W and higher when using high-hardness wire W. This suppresses surface scratches on wire W regardless of its hardness.

[0231] In one or more embodiments, the control circuit 230 determines that the hardness of the wire W differs depending on whether the wire type detection unit 214 detects a stainless steel wire or a polycoated wire.

[0232] With the above configuration, the control circuit 230 can identify differences in the hardness of the wires W, and therefore can perform control that matches the hardness of the wires W.

[0233] In one or more embodiments, the ratio of the first hardness (i.e., the hardness of the stainless steel wire) to the second hardness (i.e., the hardness of the polycoated wire) is 115% or more.

[0234] With the above configuration, the first hardness and the second hardness are clearly different, so the effect of changing the target voltage value between them is significantly demonstrated.

[0235] In one or more embodiments, the rebar tying machine 2 ties reinforcing bars R using wire W. The rebar tying machine 2 includes a feed mechanism 24 capable of performing a feed motion to feed the wire W around the reinforcing bars R, a feed motor 32 that operates the feed mechanism 24, a twisting mechanism 30 capable of performing a twisting motion to twist the wire W around the reinforcing bars R, a twisting motor 76 that operates the twisting mechanism 30, a wire type detection unit 214 that detects the type of wire W, and a control circuit 230 that controls the operation of the feed motor 32 and the twisting motor 76, respectively. When the control circuit 230 drives the feed motor 32 to perform a feed motion on the feed mechanism 24 during an initialization process to adjust the position of the wire W, it is configured to rotate the feed motor 32 by a specific target number of rotations. The control circuit 230 is configured to change the target number of rotations depending on the type of wire W detected by the wire type detection unit 214.

[0236] The amount of wire W fed by the feed motion (i.e., the distance the wire W is moved by the feed mechanism 24) varies not only depending on the number of rotations of the feed motor 32 but also on the type of wire W. For example, when using a wire W with a high coefficient of friction, the amount of wire W fed by the feed motion is greater than that of a wire W with a low coefficient of friction. This is because the higher the coefficient of friction of the wire W, the less likely slippage is to occur between the feed mechanism 24 and the wire W. Therefore, if a constant target number of rotations is used regardless of the type of wire W, the amount of wire fed by the feed motion may not be the desired amount depending on the type of wire W. With the above configuration, the target number of rotations can be changed according to the type of wire W used. For example, when using a wire W with a high coefficient of friction, the target number of rotations can be set lower, and when using a wire W with a low coefficient of friction, the target number of rotations can be set higher. This makes it possible to set the amount of wire fed by the feed motion to the desired amount regardless of the type of wire W.

[0237] In one or more embodiments, the wire type detection unit 214 is configured to distinguish and detect polycoated wires (examples of wires with a coating) and annealed wires and stainless steel wires (examples of wires without a coating). The control circuit 230 is configured to change the target number of rotations depending on whether the wire type detection unit 214 detects polycoated wires or annealed wires and stainless steel wires.

[0238] Poly-coated wires tend to be more slippery than annealed wires and stainless steel wires. Therefore, when the feeding mechanism 24 feeds out poly-coated wire, slippage may occur between the feeding mechanism 24 and the wire W, potentially resulting in a feed amount less than the desired amount. With the above configuration, the target number of rotations can be changed depending on whether poly-coated wire or annealed wire and stainless steel wire are used. For example, the target number of rotations can be set higher when using poly-coated wire and lower when using annealed wire and stainless steel wire. This makes it possible to achieve the desired feed amount through the feeding motion, regardless of the presence or absence of coating material. [Explanation of Symbols]

[0239] 2: Rebar tying machine, 4: Main unit, 4a: Power switch, 4b: Setting switch, 4c: Display unit, 6: Grip, 8: Trigger, 9: Trigger switch, 10: Battery mounting section, 12: Reel holder, 12a: Storage space, 14: Holder housing, 14a: Rotating shaft, 15: Rib, 16: Cover member, 18: Reel, 20: Control board, 24: Feed mechanism, 26: Guide mechanism, 28: Cutting mechanism, 30: Twisting mechanism, 32: Feed motor, 32a: Coil, 32b: Stator, 33: Rotation detection board, 34: Reduction unit, 36: Feed unit, 38: Base member, 40: Guide member, 40a : Guide hole, 42: Drive gear, 44: First gear, 44a: Groove, 46: Second gear, 46a: Groove, 48: Gear support member, 48a: Oscillating shaft, 52: Biasing member, 56: Wire guide, 58: Upper guide arm, 58a: Upper guide passage, 60: Lower guide arm, 60a: Lower guide passage, 61: First guide pin, 62: Second guide pin, 64: Shearing member, 66: Guide member, 68: Operating member, 70: Biasing member, 72: Guide passage, 74: Wire hole, 74a: Cutting position, 76: Torsion motor, 76a: Coil, 76b: Stator, 76c: Rotor, 78: Rotation detection board, 82: Reducer unit, 84: Sleeve unit, 86: Rotation limiting unit, 88: Gripping unit, 92: Screw shaft, 94: Inner sleeve, 96: Outer sleeve, 98: Push member, 100: Binding mechanism, 102: Ball groove, 104: Ball, 106: Cylindrical part, 108: Flange part, 110: Ball holding hole, 112: Small diameter part, 114: Large diameter part, 116: Ring sleeve, 118: C-ring, 120: Fin, 122: Short fin, 124: Long fin, 126L: Left side stopper, 126R: Right side stopper, 128a: Screw hole, 128b: Screw , 128L: base member, 128R: base member, 130L: oscillating member, 130R: oscillating member, 132L: spring, 132R: spring, 134L: oscillating shaft, 134R: oscillating shaft, 136L: regulating piece, 136R: regulating piece, 140a: initial position detection magnet, 140b: tip gripping position detection magnet, 140c: twist start detection magnet, 142a: initial position detection sensor, 142b: tip gripping position detection sensor, 142c: twist start detection sensor, 152: clamp shaft, 152a: cavity, 154: right clamp member, 156: left clamp member,158: Flat plate section, 160: Fitting hole, 162: Housing hole, 164: Pin, 166: Base section, 166a: Cam hole, 166b: Cam hole, 168: Pin holding section, 170: Clamp piece, 178: Base section, 178a: Cam hole, 178b: Cam hole, 180: Clamp piece, 182a: Engaging pin, 182b: Engaging pin, 184: Right wire passage, 186: Left wire passage, 200: Bobbin, 202: Body section, 204: Left flange section, 206: Right flange section, 208: Recess, 2 10: projection, 212: support cylinder, 214: wire type detection unit, 216: opening, 218: movable member, 220: wire type detection magnet, 222: biasing member, 224: sensor substrate, 225: guide space, 226a: Hall sensor, 226b: Hall sensor, 226c: Hall sensor, 230: control circuit, 232: power supply circuit, 234: motor current detection circuit, 236: battery voltage detection circuit, B: battery pack, CX: central axis, R: rebar, W: wire,

Claims

1. A binding machine that uses wire to bind objects, A feeding mechanism capable of performing a feeding motion to feed the wire around the object to be bundled, A feed motor that operates the feed mechanism, A torsion mechanism capable of performing a torsional motion to twist the wire around the object to be bundled, A torsion motor for operating the aforementioned torsion mechanism, A voltage detection unit for detecting the voltage of the battery that supplies power to the feed motor and the torsion motor, respectively, A wire type detection unit for detecting the type of wire, It comprises a control unit that controls the operation of the feed motor and the torsion motor, The control unit is configured to prohibit the driving of at least one of the feed motor and the torsion motor when the voltage value of the battery detected by the voltage detection unit is below a specific voltage threshold. A bundling machine wherein the control unit is configured to change the voltage threshold according to the type of wire detected by the wire type detection unit.

2. The wire type detection unit is configured to distinguish and detect wires having a first maximum tensile load and wires having a second maximum tensile load that is smaller than the first maximum tensile load. The bundling machine according to claim 1, wherein the control unit is configured to change the voltage threshold when the wire type detection unit detects a wire having the first maximum tensile load, and when the wire type detection unit detects a wire having the second maximum tensile load.

3. The binding machine according to claim 2, wherein the control unit determines that the maximum tensile load of the wire is different when the wire type detection unit detects a wire having the first maximum tensile load and when the wire type detection unit detects a wire having the second maximum tensile load.

4. The binding machine according to claim 2 or 3, wherein the ratio of the first maximum tensile load to the second maximum tensile load is 115% or more.

5. The wire type detection unit is configured to distinguish and detect wires having a first yield point load and wires having a second yield point load smaller than the first yield point load. The bundling machine according to claim 1, wherein the control unit is configured to change the voltage threshold when the wire type detection unit detects a wire having a first yield point load and when the wire type detection unit detects a wire having a second yield point load.

6. The binding machine according to claim 5, wherein the control unit determines that the yield point load of the wire is different when the wire type detection unit detects a wire having the first yield point load and when the wire type detection unit detects a wire having the second yield point load.

7. The binding machine according to claim 5 or 6, wherein the ratio of the first yield point load to the second yield point load is 115% or more.

8. A binding machine that uses wire to bind objects, A feeding mechanism capable of performing a feeding motion to feed the wire around the object to be bundled, A feed motor that operates the feed mechanism, A torsion mechanism capable of performing a torsional motion to twist the wire around the object to be bundled, A torsion motor for operating the aforementioned torsion mechanism, A wire type detection unit for detecting the type of wire, It comprises a control unit that controls the operation of the feed motor and the torsion motor, The control unit is configured to adjust the voltage applied to the feed motor to a specific target voltage value when driving the feed motor to cause the feed mechanism to perform the feed motion. A bundling machine wherein the control unit is configured to change the target voltage value according to the type of wire detected by the wire type detection unit.

9. The wire type detection unit is configured to distinguish and detect wires having a first hardness and wires having a second hardness that is less than the first hardness. The bundling machine according to claim 8, wherein the control unit is configured to change the target voltage value when the wire type detection unit detects a wire having the first hardness and when the wire type detection unit detects a wire having the second hardness.

10. The bundling machine according to claim 9, wherein the control unit determines that the hardness of the wire differs depending on whether the wire type detection unit detects a wire having a first hardness or a wire having a second hardness.

11. The binding machine according to claim 9 or 10, wherein the ratio of the first hardness to the second hardness is 115% or more.

12. A binding machine that uses wire to bind objects, A feeding mechanism capable of performing a feeding motion to feed the wire around the object to be bundled, A feed motor that operates the feed mechanism, A torsion mechanism capable of performing a torsional motion to twist the wire around the object to be bundled, A torsion motor for operating the aforementioned torsion mechanism, A wire type detection unit for detecting the type of wire, It comprises a control unit that controls the operation of the feed motor and the torsion motor, The control unit is configured to rotate the feed motor by a specific target number of rotations when driving the feed motor to cause the feed mechanism to perform the feed motion during the initialization process for adjusting the position of the wire. A bundling machine wherein the control unit is configured to change the target number of rotations according to the type of wire detected by the wire type detection unit.

13. The wire type detection unit is configured to distinguish and detect wires having a coating material from wires without a coating material. The bundling machine according to claim 12, wherein the control unit is configured to change the target number of rotations depending on whether the wire type detection unit detects a wire having the covering material or a wire without the covering material.

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