Nail guns and their control methods

Abstract

This invention discloses a nail gun and its control method. The nail gun includes: a housing; a cylinder connected to the housing and used to store gas; a firing assembly, at least partially disposed within the cylinder, capable of moving from an initial position to a firing position within the cylinder to fire a nail; a power output unit disposed within a receiving space formed by the housing to drive the firing assembly to move within the cylinder; a motor capable of driving the power output unit to move the firing assembly within the cylinder; an anomaly detection unit for detecting abnormal alarm information occurring during the operation of the nail gun; and a control unit electrically connected at least to the anomaly detection unit and the motor. The control unit is configured to: upon receiving an abnormal alarm information, control the motor to drive the power output unit to move the firing assembly to a preset stop position, and control the motor to brake and stop when the firing assembly reaches the preset stop position. This invention provides a nail gun that can safely and reliably handle abnormal situations during operation.

Description

Technical Field

[0001] This invention relates to the field of power tool technology, and more specifically to a nail gun and its control method. Background Technology

[0002] As a nail-driving tool, a nail gun's firing pin always stops at a specific position after each nailing operation—either the initial position or a nearby position. During operation, abnormal situations such as overheating or low battery voltage may occur. A common practice to address these issues is to disconnect the drive circuit to stop the motor upon detection. However, if the firing pin is near the stop position, disconnecting the drive and stopping the motor may lead to a dangerous situation of two consecutive nailing attempts due to the motor's inertia. For example, if the firing pin is near the initial firing position, disconnecting the drive and stopping the motor might cause it to release to near the lower dead center, potentially causing it to overshoot the safety switch and preventing subsequent safety switch activation. If the same fault occurs at other locations, disconnecting the drive and stopping the motor may not accurately determine the firing pin's position, resulting in the firing pin stopping near the stop position during the next nailing attempt, without any nail being fired or other issues arising. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a nail gun that can safely and reliably handle abnormal situations during operation.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A nail gun includes: a housing; a cylinder connected to the housing and used to store gas; a firing assembly at least partially disposed within the cylinder, capable of moving within the cylinder from an initial position to a firing position to fire a nail; a power output unit disposed within a receiving space formed by the housing to drive the firing assembly to move within the cylinder; a motor capable of driving the power output unit to move the firing assembly within the cylinder; an anomaly detection unit for detecting anomaly alarm information occurring during the operation of the nail gun; and a control unit electrically connected at least to the anomaly detection unit and the motor; the control unit is configured to: upon receiving the anomaly alarm information, control the motor to drive the power output unit to move the firing assembly to a preset stop position, and control the motor to brake and stop when the firing assembly reaches the preset stop position.

[0006] Furthermore, the nail gun also includes: a drive circuit connected between the control unit and the motor, the drive circuit including multiple power components capable of driving the motor to rotate; the control unit is configured to:

[0007] When the firing assembly moves to the preset stop position, the power element in the drive circuit is short-circuited to brake the motor.

[0008] Furthermore, the control unit is configured to control the motor to brake and stop when an abnormal alarm information of motor stall is received.

[0009] Furthermore, it also includes an alarm unit, which outputs corresponding alarm prompts based on the type of abnormal alarm information detected.

[0010] Furthermore, the power output unit includes at least a drive shaft, on which a drive wheel is disposed; the firing assembly includes a firing pin, which is provided with transmission teeth that can engage with the drive wheel.

[0011] Furthermore, it also includes: a position detection unit for detecting the position of the firing assembly within the cylinder; the position detection unit includes a magnetic induction assembly; the magnetic induction assembly includes: a first sensing element disposed on the housing; a second sensing element disposed on an insulating member parallel to the drive wheel; the control unit is configured to: acquire the rotational position of the drive wheel detected by the magnetic induction assembly, calculate the movement position of the firing pin within the cylinder based on the rotational position of the drive wheel; and when the firing pin moves to the preset stop position, control the motor to brake and stop, thereby stopping the movement of the firing pin.

[0012] Furthermore, the anomaly detection unit includes a voltage detection module, used to detect whether the output voltage of the power supply device that provides power to the nail gun is less than or equal to a preset undervoltage value.

[0013] Furthermore, the anomaly detection unit also includes a temperature detection module, used to detect whether the temperature of the power supply device is greater than or equal to a preset first temperature threshold.

[0014] Furthermore, the temperature detection module is also used to detect whether the temperature on the control circuit board inside the nail gun is greater than or equal to the second temperature threshold.

[0015] A method for controlling a nail gun, the nail gun comprising: a housing; a cylinder connected to the housing and used to store gas; a firing assembly at least partially disposed within the cylinder, capable of moving within the cylinder from an initial position to a firing position to fire a nail; a power output unit disposed within a receiving space formed by the housing to drive the firing assembly to move within the cylinder; a motor capable of driving the power output unit to move the firing assembly within the cylinder; and an anomaly detection unit for detecting an abnormal alarm information occurring during the operation of the nail gun; the method comprising: upon receiving the abnormal alarm information, controlling the motor to drive the power output unit to move the firing assembly to a preset stop position, and controlling the motor to brake and stop when the firing assembly reaches the preset stop position.

[0016] The advantages of this invention are: by controlling the nail gun to drive the firing pin to the stop position under abnormal conditions and performing brake control at the stop position, the safety of the nail gun control under abnormal conditions is improved, and the nail gun can work normally after restarting, thus improving the user experience. Attached Figure Description

[0017] Figure 1 It is a 3D diagram of a nail gun;

[0018] Figure 2 yes Figure 1 A cross-sectional view of the nail gun;

[0019] Figure 3 yes Figure 1 A schematic diagram of the internal structure of the nail gun in its initial position;

[0020] Figure 4 yes Figure 1 A schematic diagram of the internal structure of a nail gun in the firing position;

[0021] Figure 5 yes Figure 1 A 3D schematic diagram of the drive wheel of the nail gun in the picture;

[0022] Figure 6 This is a circuit diagram of one implementation of a nail gun;

[0023] Figure 7 This is a schematic diagram of the structure of an anomaly detection unit for a nail gun according to one embodiment;

[0024] Figure 8 The flowchart shows a control method for one embodiment of the nail gun. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0026] Figures 1 to 2 The nail gun 100 shown includes a housing 11, a power output unit 12, a cylinder 13, and a magazine assembly 14. The housing 11 includes a first receiving space 111 extending along a first straight line 101 and a second receiving space 112 extending along a second straight line 102. The power output unit 12 is disposed within the first receiving space 111, and the cylinder 13 is disposed within the second receiving space 112. The housing 11 also has a handle 113 for user gripping. One end of the handle 113 is connected to a power interface for connecting to a DC or AC power source. A main switch 113a is provided on the handle 113, allowing the user to control the start and stop of the nail gun 100. In this embodiment, the power supply for the nail gun 100 can be a battery pack 15. The other end of the handle 113 is connected to the cylinder 13, which extends along the second straight line 102, with the first straight line 101 and the second straight line 102 perpendicular to each other. The magazine assembly 14 is positioned along a third straight line 103 parallel to the first straight line 101. As an optional implementation, the magazine assembly 14 also includes a window 141 for the user to observe the remaining nails. The window 141 is configured as one or more notches on the magazine assembly 14, allowing the user to check the remaining nails and also enabling simple maintenance of the magazine assembly 14 without disassembling it. A firing assembly 16 is housed in the cylinder 13. Work is done by the gas in the cylinder 13, propelling the firing assembly 16 to fire the nails. In this embodiment, the cylinder 13 also includes an air inlet for pre-filling the cylinder 13 with gas. The power output unit 12 drives the firing assembly 16 to compress the gas from its initial position to its firing position. During this process, the gas performs work, and under the influence of the pre-filled gas, continuously pushes the firing assembly 16, giving it acceleration. This allows the firing assembly 16 to fire the nails with greater kinetic energy. After firing the nails, it quickly returns from the firing position to the initial position, thus completing one nail-firing cycle.

[0027] like Figure 3 and Figure 4The power output unit 12 extends substantially along the direction of the first straight line 101, and the cylinder 13 and the firing assembly 16 disposed in the cylinder 13 extend substantially along the direction of the second straight line 102. The power output unit 12 and the cylinder 13 are disposed substantially perpendicularly. The motor 121 can be used as a power source to drive the power output unit 12 to move the firing assembly 16 within the cylinder 13. In an alternative implementation, the motor 121 can be part of the power output unit 12. It can output power to the drive shaft 124, and the drive wheel 125 is disposed on the drive shaft 124. The firing assembly 16 includes a firing pin 161 and a piston (not shown). The piston and the firing pin 161 are fixedly connected or detachably connected, and the firing pin 161 has a transmission tooth 161a formed thereon, both of which can move within the cylinder 13 along the direction of the second straight line 102. The drive wheel 125 can cooperate with the transmission tooth 161a to drive the firing assembly 16 to overcome the air pressure in the cylinder 13, thereby allowing the firing assembly 16 to enter the cylinder 13. Figure 3 The initial position is shown.

[0028] like Figure 4 and Figure 5 As shown, the drive wheel 125 is a gear structure. The drive wheel 125 also has a second connecting hole 125a for connection to the drive shaft 124. Specifically, the second connecting hole 125a is a flat hole, allowing the drive wheel 125 to rotate synchronously with the drive shaft 124 when connected to it. Multiple drive teeth 125g are formed around the main body of the drive wheel 125. Each drive tooth 125g includes a first tooth 125b at the starting end and a second tooth 125d at the ending end. Here, the drive tooth 125g that first contacts the firing pin 161 in the firing assembly 16 when the drive wheel 125 begins to drive the firing assembly 16 back to its initial position is defined as the first tooth 125b, and the drive tooth 125g that last engages with the firing pin 161 in the firing assembly 16 after the firing assembly 16 has reached its initial position is defined as the second tooth 125d. The first tooth 125b and the second tooth 125d are separated by a first section 125e and a second section 125f. The first section 125e has a plurality of evenly distributed drive teeth 125g; the second section 125f is smooth and continuous, and has no drive teeth 125g distributed thereon. When the drive teeth 125g of the first section 125e mesh with the transmission teeth 161a on the striker 161, the drive wheel 125 drives the striker 161 to compress the gas in the cylinder 13 to do work. When the second section 125f engages with the striker 161, because the second section 125f is smooth and continuous, the striker 161, without the stop of the drive teeth 125g, is rapidly pushed out by the gas in the cylinder 13, thus achieving the nail-driving effect.

[0029] like Figure 6As shown, the control circuit of the nail gun 100 may include an abnormality detection unit 10, a control unit 20, a power conversion circuit 30, a drive circuit 40, and a motor 121.

[0030] In one embodiment, the power conversion circuit 30 is connected to the battery pack 15 and is used to convert the electrical energy output by the battery pack 15 into a power supply voltage that can power the control unit 20 and the motor 121, etc.

[0031] In one embodiment, the drive circuit 40 is connected between the control unit 20 and the motor 121, and can receive control signals output by the control unit 20. By changing its own conduction state, it can control the speed or direction of rotation of the motor 121. Optionally, the drive circuit 40 may consist of one or more power components. In one embodiment, such as... Figure 6 As shown, the drive circuit 40 includes multiple power elements VT1, VT2, VT3, VT4, VT5, and VT6. The gate of each power element is electrically connected to the control unit 20 to receive control signals from the control unit 20. Each drain or source of the power element is connected to the stator winding of the motor 121. Power elements VT1-VT6 receive control signals from the control unit 20 and change their respective conduction states, thereby changing the current applied to the stator winding of the motor by the battery pack. In one embodiment, the drive circuit 40 may be a three-phase bridge driver circuit including six controllable semiconductor power devices (e.g., FETs, BJTs, IGBTs, etc.). It is understood that the aforementioned power elements may also be any other type of solid-state switch, such as an insulated-gate bipolar transistor (IGBT), a bipolar junction transistor (BJT), etc.

[0032] To enable the motor 121 to rotate, the drive circuit 40 has multiple drive states. In one drive state, the stator winding of the motor generates a magnetic field. The control unit 20 outputs a corresponding PWM control signal to the switching element in the drive circuit according to the rotor position or back electromotive force of the motor, so that the drive circuit switches the drive state, thereby generating a changing magnetic field in the stator winding to drive the rotor to rotate, thus realizing the rotation or commutation of the motor. It should be noted that any other circuit and control method capable of driving the rotation or commutation of the motor can be used in this disclosure. This disclosure does not limit the circuit structure of the drive circuit 40 or the control of the drive circuit 40 by the control unit 20.

[0033] In one embodiment, the anomaly detection unit 10 can detect various abnormalities that occur in the nail gun 100 during operation, such as battery pack undervoltage, battery pack overheating, internal overheating of the nail gun, motor stall, or overcurrent. In other words, the anomaly detection unit 10 can detect various abnormalities in the operation of the nail gun 100 during the movement of the power output unit 12.

[0034] In one embodiment, such as Figure 7 As shown, the anomaly detection unit 10 may include a voltage detection module 101, a temperature detection module 102, or a stall detection module 103. The voltage detection module 101 is used to detect whether the output voltage of the battery pack supplying power to the nail gun 100 is less than or equal to a preset undervoltage value; if it is less, it outputs an undervoltage alarm message. The temperature detection module 102 is used to detect whether the temperature of the battery pack is greater than or equal to a preset first temperature threshold, i.e., to detect whether the battery pack is overheated; if so, it outputs a first overheat alarm message. In an optional implementation, the temperature detection module 102 is also used to detect whether the temperature on the control circuit board inside the nail gun 100 or the temperature of the power components on the circuit board is greater than or equal to a second temperature threshold; if so, it outputs a second overheat alarm message. In this embodiment, the relationship between the first and second temperature thresholds is not limited, nor is the type of the first and second overheat alarm messages being the same. The stall detection module 103 can be used to detect whether the motor 121 is stalled, and can output a stall alarm message when stalling is detected.

[0035] In one embodiment, the control unit 20 may include a control chip that, when no abnormality is present, controls the motor 121 to rotate normally, driving the firing assembly 16 to perform the nail-driving action. If the aforementioned abnormality detection unit 10 detects an abnormality alarm, the control unit 20, upon receiving the alarm, will not immediately brake the motor. Instead, it will continue to control the motor 121 to drive the power output unit 12 to move the firing assembly 16 to a preset stop position, and will brake the motor to stop when the firing assembly 16 reaches the preset stop position. In this embodiment, when an abnormality occurs during the operation of the nail gun 100, it will not stop immediately, but will ensure that the firing assembly 16 can still move to the preset stop position before stopping. This avoids safety issues or inconvenience in reusing the firing assembly due to uncontrollable position within the cylinder after an abnormal stop of the nail gun. In this embodiment, after the firing assembly 16 reaches the preset stop position, the control unit 20 can control the power components in the drive circuit 40 to short-circuit, thereby short-circuiting the windings of each phase of the motor. The kinetic energy of the motor can be quickly converted into heat energy, causing the motor to stop rotating quickly.

[0036] Understandably, when the abnormality detection unit 10 detects an abnormality alarm, if the firing assembly 16 is exactly in the initial position, the control unit 20 can immediately control the power element in the drive circuit 40 to short-circuit, so that the motor can brake and stop immediately; if the firing assembly 16 is in any other position besides the initial position, the control unit 20 needs to continue driving the motor to move the firing assembly 16 to the initial position before controlling the power element in the drive circuit 40 to short-circuit, so that the motor can brake and stop.

[0037] In one embodiment, the nail gun 100 also includes a position detection unit 50, which can detect the position of the firing assembly 16 within the cylinder. This allows the control unit 20 to determine the moment when the firing assembly 16 moves to the preset stop position after receiving an abnormal alarm message, thereby ensuring that when the firing assembly 16 reaches the stop position, the abnormal alarm message is responded to and the motor is braked to stop.

[0038] In one embodiment, the position detection unit 50 may include a magnetic induction component (not shown), which includes a first sensing element disposed on the housing 11, and a second sensing element disposed on an insulating member parallel to the drive wheel 125. The control unit 20 can acquire the rotational position of the drive wheel detected by the magnetic induction component, and thus calculate the movement position of the striker in the cylinder based on the rotational position of the drive wheel. In an optional implementation, the first sensing element is a Hall element, and the second sensing element is a magnetic element. The Hall element is disposed at a preset position on the housing 11, and the magnetic element is disposed on an insulating member parallel to the drive wheel. The insulating member can be distributed around the magnetic element, thereby preventing the magnetic element from magnetizing the drive tooth 125g and affecting the signal reception of the Hall element. It is understood that the insulating member is fixedly connected to the drive wheel 125 and can rotate synchronously with the drive wheel 125. When the drive wheel 125 rotates to the preset position, the magnetic element transmits a signal to the Hall element, and the Hall element can transmit the signal to the control unit 20. Understandably, the control unit 20 can identify the position of the drive wheel 125 based on the signal transmitted by the Hall element, and can also estimate the position of the striker within the cylinder based on the drive rotation relationship between the drive wheel and the striker in one nailing cycle. For example, when the first gear 125b of the drive wheel contacts the striker 161, the striker is in the initial position; when the second gear 125d contacts the striker, the striker is in the firing position. Therefore, the position of the striker can be calculated within one nailing cycle based on the number of gears in the drive gear and which gear contacts the striker.

[0039] In one embodiment, the position detection unit 50 may also be a sensor, such as a photoelectric device (not shown), capable of detecting the movement position of the impact pin within the cylinder. The photoelectric device can trigger a photoelectric signal when the impact pin moves to a preset position. When the control unit 20 receives the photoelectric signal, it can determine that the impact pin has moved to a preset stopping position, thereby controlling the motor to brake, causing the impact pin to rapidly reduce its moving speed and eventually stop at its initial position. Optionally, the photoelectric device may be located inside or outside the cylinder, or at other locations capable of detecting the impact pin's movement within the cylinder.

[0040] In one embodiment, the nail gun 100 may also include an alarm unit 60, which can output corresponding alarm prompts based on the type of abnormal alarm information detected. For example, when the battery pack is undervoltage, the alarm unit 60 can output an audible prompt or a light prompt with a certain flashing frequency or color; when the battery pack temperature is too high, it can output a different audible prompt or a light prompt with a different flashing frequency or color. Thus, the user can intuitively determine the type of abnormality currently existing in the nail gun 100 based on the type of alarm prompt output by the alarm unit 60, so as to resolve the abnormality as quickly as possible. It should be noted that the alarm unit 60 can output alarm prompts after the motor stops and brakes, or when the abnormality detection unit 10 detects abnormal alarm information.

[0041] In one embodiment, if the above-mentioned abnormal alarm information is an abnormal alarm when the motor is stalled, the control unit 20 will control the motor to stop and brake immediately, without forcibly driving the firing component 16 to the initial position.

[0042] The following will combine Figure 8 This describes the control method for a nail gun, which includes the following steps:

[0043] S101, determine whether an abnormal alarm message has been obtained. If not, continue the detection; otherwise, proceed to step S102.

[0044] It should be noted that the above abnormal alarm information includes undervoltage, overtemperature, or overcurrent information, but does not include stall alarm information.

[0045] S102, control the motor to drive the power output unit to move the firing assembly to the preset stop position.

[0046] S103 controls the motor to brake and stop.

[0047] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1.A nail gun, comprising: a housing; a cylinder connected to the housing and configured to store gas; a firing assembly at least partially disposed in the cylinder and movable within the cylinder from an initial position to a firing position to drive a nail; a power output disposed in a receiving space formed in the housing and configured to drive the firing assembly to move within the cylinder; a motor configured to drive the power output to drive the firing assembly to move within the cylinder; an abnormality detection unit configured to detect an abnormality alarm during operation of the nail gun; a control unit electrically connected to at least the abnormality detection unit and the motor; the control unit is configured to: control the motor to drive the power output to drive the firing assembly to move to a preset stop position when the abnormality alarm is detected, and control the motor to brake when the firing assembly reaches the preset stop position. 2.The nail gun of claim 1, further comprising: a drive circuit connected between the control unit and the motor, the drive circuit comprising a plurality of power elements configured to drive the motor to rotate; the control unit is configured to: short-circuit the power elements in the drive circuit to brake the motor when the firing assembly moves to the preset stop position. 3.The nail gun of claim 1, further comprising: an alarm unit configured to output an alarm prompt corresponding to a type of the detected abnormality alarm. 4.The nail gun of claim 1, wherein: the power output comprises at least a drive shaft having a drive wheel disposed thereon; the firing assembly comprises a striker having a transmission tooth configured to cooperate with the drive wheel. 5.The nail gun of claim 4, further comprising: a position detection unit configured to detect a position of the firing assembly within the cylinder; the position detection unit comprises a magnetic induction assembly; the magnetic induction assembly comprises: a first induction element disposed on the housing; a second induction element disposed on an insulating member parallel to the drive wheel; the control unit is configured to: obtain a rotational position of the drive wheel detected by the magnetic induction assembly, and calculate a moving position of the striker within the cylinder based on the rotational position of the drive wheel; and control the motor to brake when the striker moves to the preset stop position, so that the striker stops moving. 6.The nail gun of claim 1, wherein: the abnormality detection unit comprises: a voltage detection module configured to detect whether an output voltage of a power supply device configured to supply power to the nail gun is less than or equal to a preset under-voltage value. 7.The nail gun of claim 6, wherein: the abnormality detection unit further comprises: a temperature detection module configured to detect whether a temperature of the power supply device is greater than or equal to a preset first temperature threshold. 8.The nail gun of claim 7, wherein: the temperature detection module is further configured to detect whether a temperature on a control circuit board in the nail gun is greater than or equal to a second temperature threshold. ​ ​ ​ 9. A control method of a nail gun, the nail gun comprising: A housing; a cylinder connected to the housing and used for storing gas; A firing assembly arranged at least partially in the cylinder and movable in the cylinder from an initial position to a firing position to drive out a nail; A power output arranged in a receiving space formed in the housing to drive the firing assembly to move in the cylinder; a motor capable of driving the power output to drive the firing assembly to move in the cylinder; An abnormality detection unit for detecting abnormal alarm information occurring in the operation of the nail gun; the method comprises: when the abnormal alarm information is acquired, controlling the motor to drive the power output to drive the firing assembly to move to a preset shutdown position, and controlling the motor to brake and stop when the firing assembly reaches the preset shutdown position.

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