Parts Transfer System and Parts Welding System

Abstract

To reduce a gas supply source in a component transfer system which transfers a component to a target position.SOLUTION: A component transfer system 1 includes: a lifting mechanism 2 which moves up a component N from a lower position G2 to an upper position G1; a chute 3 which drops the component N sent from the upper position G1 of the lifting mechanism 2; and a supply mechanism 4 which receives the component N dropped from the chute 3 with a stopper 65 and supplies the component N received with the stopper 65 to a target position J by a rod 40 moving forward. The chute 3 extends downward from the upper position G1 of the lifting mechanism 2 to the supply mechanism 4 without returning upward.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a part transfer system and a part welding system. [Background technology]

[0002] In Patent Document 1, the part supply device receives parts sent from the part aligner via a tube in a part holder attached to the tip of a rod, and then supplies the parts received by the part holder to the target position by moving the rod forward. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-192499 A (particularly Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the tube connecting the part aligner and the part supply device extends upward from the part aligner, then changes direction and extends downward to reach the part supply device. As a result, the parts must move from bottom to top within the tube against gravity as they are sent from the part aligner to the part supply device via the tube.

[0005] In order to move the parts from bottom to top inside the tube against gravity, the parts must be forced upward by gas, which requires a gas pressure-feeding mechanism that uses compressed air, etc. In order to install such a gas pressure-feeding device, a gas supply source is essential for supplying gas to the gas pressure-feeding device.

[0006] The present disclosure has been made in view of the above points, and an object thereof is to reduce the gas supply source in a part transfer system that transfers parts to a destination position. [Means for solving the problem]

[0007] The part transfer system of the present disclosure comprises a lifting mechanism that lifts parts from a lower position to an upper position, a chute that drops the parts sent from the upper position of the lifting mechanism, and a supply mechanism that receives the parts that have dropped from the chute with a stopper and supplies the parts received by the stopper to a target position by advancing a rod, and the chute extends downward from the upper position of the lifting mechanism to the supply mechanism without returning upward.

[0008] With this configuration, the parts are raised from a lower position to an upper position in the lifting mechanism, dropped downward from the upper position of the lifting mechanism by a chute, received by a stopper of the supply mechanism, and supplied to the target position by the advancement of the rod of the supply mechanism.

[0009] The chute extends downward from the upper position of the lifting mechanism to the supply mechanism without returning upward. The parts naturally fall downward by gravity in the chute from the upper position of the lifting mechanism to the supply mechanism without returning upward.

[0010] This reduces the need to install a gas pumping mechanism for pumping gas to move parts from below to above in the chute against gravity, thereby reducing the need to use a gas supply source to supply gas to such a gas pumping device.

[0011] As described above, the gas supply source can be reduced in a part transfer system that transfers parts to a target position.

[0012] In one embodiment, the lifting mechanism includes an outer tube that extends vertically, a plurality of suction sections arranged in a spiral shape on the inner surface of the outer tube with a central axis that extends vertically and that apply a magnetic field to the outer surface of the outer tube to attract the parts to the outer surface of the outer tube, a rotational drive section that rotates the plurality of suction sections around the central axis, and a regulating section that regulates the rotational movement of the parts and moves the parts upward along the outer surface of the outer tube.

[0013] With this configuration, the part is attached to the outer surface of the outer cylinder by some of the spirally arranged suction parts. As the suction parts rotate around the central axis, the part attempts to rotate along the outer surface of the outer cylinder. However, the rotational movement of the part is restricted by the restricting parts. In other words, the part does not rotate even though the suction parts rotate.

[0014] Because the suction parts are arranged in a spiral and the outer cylinder extends vertically, as the suction parts rotate, new suction parts appear one after another above the part. The part is drawn to the successive suction parts and moves upward along the outer surface of the outer cylinder.

[0015] The lifting mechanism can lift the parts upward with a simple configuration.

[0016] In one embodiment, the lifting mechanism has a front / back sorting section that, based on the difference in protruding thickness from the outer surface of the outer tube, allows the part to pass when the front surface is facing the outer surface, but rejects the part to prevent it from passing when the back surface is facing the outer surface.

[0017] With this configuration, the lifting mechanism can distinguish between the front and back sides of the parts and convert them into a uniform posture.

[0018] In one embodiment, the lifting mechanism has a reservoir portion at the lower position for storing a plurality of the parts.

[0019] With this configuration, the lifting mechanism can preferably lift the parts upward from the reservoir located in the lower position.

[0020] In one embodiment, the lifting mechanism has a direction changing section that changes the direction of the part moving upward along the outer surface of the outer cylinder to downward at the upper position.

[0021] With this configuration, the part can be smoothly sent to the chute for the subsequent process while moving downward by changing the direction of the part from above to below using the direction changer located at the upper position in the lifting mechanism.

[0022] In one embodiment, the chute has a tubular member through which the part passes and a long plate member arranged inside the tubular member and extending along the tubular member, and the part slides along the long plate member.

[0023] With this configuration, in the chute, the parts slide against the long plate member arranged inside the tubular member, preventing the parts from coming into direct contact with the tubular member, thereby reducing damage to the tubular member.

[0024] Furthermore, because the parts fall smoothly downward in the chute, the use of a gas pumping device for pumping the parts downward in the chute with gas can be reduced, contributing to a reduction in the gas supply source.

[0025] In one embodiment, the cylindrical member is made of a flexible material, and the long plate member is made of a material that is harder than the material that makes up the cylindrical member and that is elastically deformable.

[0026] With this configuration, by bending the flexible tubular member, the elastically deformable elongated plate member can be deformed along with the flexible tubular member. Furthermore, because the elongated plate member is harder than the tubular member, frictional resistance when the parts slide against the elongated plate member can be reduced, making it easier for the parts to slide against the elongated plate member. Even if the chute is made to snake, the parts can be dropped down the chute.

[0027] Furthermore, because the parts fall smoothly downward in the chute, the use of a gas pumping device for pumping the parts downward in the chute with gas can be reduced, contributing to a reduction in the gas supply source.

[0028] In one embodiment, the part has a protrusion provided on a rear surface, and the protrusion of the part slides on the long plate member.

[0029] With this configuration, there is a concern that if the protrusion of the part comes into contact with the tubular member in the chute, the tubular member may be damaged.However, by having the protrusion of the part slide against the long plate member, the protrusion of the part is prevented from coming into direct contact with the tubular member, thereby preventing damage to the tubular member.

[0030] Furthermore, because the parts fall smoothly downward in the chute, the use of a gas pumping device for pumping the parts downward in the chute with gas can be reduced, contributing to a reduction in the gas supply source.

[0031] In one embodiment, the supply mechanism has an actuator that moves the rod back and forth, and the actuator is an electric actuator.

[0032] According to this configuration, in the supply mechanism, it is not necessary to use a gas supply source for the actuator to move the rod back and forth.

[0033] In one embodiment, the supply mechanism includes the rod that supplies the part having a through hole to the target position by advancing forward, a piston connected to the rod, a cylinder that houses the rod and the piston, a lid that closes the cylinder forward of the piston and through which the rod extending forward from the piston passes, and an actuator that moves the piston and the rod back and forth, wherein the piston, the cylinder, and the lid define a gas chamber, and the rod includes: a gas outlet that is provided on the outer periphery of the front end of the rod that is inserted into the through hole of the part, and through which gas is blown out; a gas inlet that is provided rearward of the gas outlet and through which the gas is introduced from the gas chamber; and a gas passage that extends back and forth inside the rod and through which the gas passes from the gas inlet to the gas outlet.

[0034] With this configuration, as the rod advances, the front end of the rod is inserted into the through-hole of the part, and the part hung on the front end of the rod is supplied to the target position by the advancement of the rod.

[0035] Gas is stored in a gas chamber defined by the piston, cylinder, and lid. When the piston moves forward, the gas in the gas chamber is compressed. The gas compressed in the gas chamber is introduced into the gas inlet of the rod. The gas introduced into the gas inlet passes through a gas passage inside the rod and is blown out from a gas outlet on the outer periphery of the front end of the rod.

[0036] The gas is blown out from the gas outlet on the outer periphery of the front end of the rod toward the part hung on the front end of the rod, thereby holding the part on the front end of the rod.

[0037] The supply mechanism utilizes a gas chamber partitioned by a piston, a cylinder, and a lid, so that the part can be held at the front end of the rod by blowing gas out from the gas outlet without using a gas supply source.

[0038] The part welding system according to the present disclosure comprises the part transfer system and a resistance welding machine, the resistance welding machine including a lower electrode and an upper electrode, the target position being between the lower electrode and the upper electrode, a guide pin protruding and retracting from a tip of at least one of the lower electrode and the upper electrode, the guide pin protruding from the tip due to an elastic force of an elastic member and retracting from the tip by being pressed against the elastic force of the elastic member.

[0039] At the target position, the guide pin can be extended and retracted from the tip of at least one of the lower electrode and the upper electrode without using a gas supply source.

[0040] In one embodiment, the resistance welding machine includes a resistance welding machine actuator, which compresses a gas chamber for the resistance welding machine by moving the upper electrode downward and simultaneously moving a resistance welding machine piston arranged in a resistance welding machine cylinder downward, and the gas chamber for the resistance welding machine is connected to the outer surface side of the guide pin, and the gas compressed in the gas chamber for the resistance welding machine escapes upward along the outer surface of the guide pin.

[0041] According to this configuration, dust (welding dust, etc.) generated by the resistance welding machine can be removed by blowing gas without using a gas supply source. [Effects of the Invention]

[0042] According to the present disclosure, it is possible to reduce the gas supply source in a part transfer system that transfers parts to a destination position. [Brief explanation of the drawings]

[0043] [Figure 1] FIG. 1 shows a chute and a supply mechanism in a nut transfer system according to this embodiment. [Figure 2] FIG. 2 shows a lifting mechanism in the nut transfer system according to this embodiment. [Figure 3] FIG. 3 shows a perspective view of the nut. [Figure 4] FIG. 4 shows a perspective view of the outer cylinder of the lifting mechanism. [Figure 5] FIG. 5 shows a perspective view of the shaft and magnet in the lifting mechanism. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI in FIG. 4, showing a state in which the surface of the nut faces the outer surface of the outer cylinder in the lifting mechanism. [Figure 7] FIG. 7 is a view equivalent to FIG. 6, showing a state in which the back surface of the nut faces the outer surface of the outer cylinder in the lifting mechanism. [Figure 8] FIG. 8 shows the attitude change guide of the lifting mechanism as seen from the arrow VIII in FIG. [Figure 9] FIG. 9 shows a cross-sectional view of the direction change guide of the lifting mechanism taken along line IX in FIG. [Figure 10] FIG. 10 shows the chute in an X-ray cross section of FIG. [Figure 11] FIG. 11 shows a front view of the nut feeding mechanism before the rod is inserted into the threaded hole of the nut. [Figure 12] FIG. 12 shows a front view of the nut feeding mechanism after the rod has been inserted into the threaded hole in the nut. [Figure 13] FIG. 13 shows a front view of the nut feeding mechanism at the moment when the rod feeds the nut to the target position. [Figure 14] FIG. 14 shows a front view of the nut feeding mechanism after the rod has retracted from its destination position. [Figure 15] FIG. 15 is a perspective view of the nut receiver. [Figure 16] FIG. 16 shows the rod in plan view. [Figure 17] FIG. 17 shows the sealing mechanism in side view. [Figure 18] FIG. 18 shows a front view of the sealing mechanism. [Figure 19] FIG. 19 shows the lower electrode unit of a resistance welding machine. [Figure 20] FIG. 20 shows a bolt transport system according to another embodiment. [Figure 21]FIG. 21 shows a resistance welding machine according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0044] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0045] <Nut welding system> The nut welding system S as a parts welding system according to this embodiment will be described. The nut welding system S includes a nut transfer system 1 as a parts transfer system, and a resistance welder 100.

[0046] <Nut transfer system> A nut transfer system 1 as a part transfer system according to this embodiment will be described. Fig. 1 shows a chute 3 and a supply mechanism 4 in the nut transfer system 1 according to this embodiment. Fig. 2 shows a lifting mechanism 2 in the nut transfer system 1 according to this embodiment.

[0047] The nut transfer system 1 includes a lifting mechanism 2, a chute 3, and a supply mechanism 4. The nut transfer system 1 is applied to a resistance welding machine 100. The nut transfer system 1 transfers a nut N as a part to a target position J between a lower electrode 104 and an upper electrode 109 in the resistance welding machine 100.

[0048] <Nut> FIG. 3 shows a perspective view of a nut N. The nut transfer system 1 uses the nut N as a part to be transferred. The nut N is a rectangular weld nut. The nut N has a main body N1 and four protrusions N3. The main body N1 has a predetermined thickness t. The main body N1 is approximately rectangular. The front surface N1a and the back surface N1b of the main body N1 are parallel to each other and are approximately square. The four protrusions N3 are provided at the four corners of the back surface N1b of the main body N1. The protrusions N3 protrude toward the back surface N1b.

[0049] The overall thickness T of the nut N is the thickness t of the main body N1 alone plus the protruding dimension of the protrusion N3. The nut N has a screw hole N2 as a through hole. The screw hole N2 penetrates the center of the main body N1. The main body N1 of the nut N has four side surfaces N1c. The side surfaces N1c connect the front surface N1a and the back surface N1b of the main body N1. The distance between two opposing side surfaces N1c of the main body N1 of the nut N is the two-face width dimension s. The diagonal distance between the corners of the main body N1 of the nut N is the diagonal dimension e.

[0050] <Lifting mechanism> The lifting mechanism 2 will be described with reference to FIGS.

[0051] FIG. 2 shows a perspective view of the entire lifting mechanism 2. FIG. 4 shows a perspective view of the outer cylinder 10 of the lifting mechanism 2. FIG. 5 shows a perspective view of the shaft 14 and magnet 13 of the lifting mechanism 2. FIG. 6 shows a cross-sectional view taken along line VI in FIG. 4, illustrating a state in which the surface N1a of the nut N faces the outer surface 11 of the outer cylinder 10 in the lifting mechanism 2. FIG. 7 is a view equivalent to FIG. 6, illustrating a state in which the back surface N1b of the nut N faces the outer surface 11 of the outer cylinder 10 in the lifting mechanism 2. FIG. 8 shows a cross-sectional view taken along line VIII in FIG. 4, illustrating the posture change guide 19 of the lifting mechanism 2. FIG. 9 shows a cross-sectional view taken along line IX in FIG. 4, illustrating the direction change guide 24 of the lifting mechanism.

[0052] The up-down direction in FIG. 2 is the up-down direction (indicated by Z). The top in FIG. 2 is the up (indicated by Z1). The bottom in FIG. 2 is the down (indicated by Z2).

[0053] The lifting mechanism 2 has an outer tube 10, a plurality of magnets 13 as a plurality of adsorption parts, a shaft 14 as part of the rotation drive part, a motor 15 as part of the rotation drive part, a regulating guide 16 as a regulating part, a posture change guide 19 as a posture change part, a stopper guide 20, a front / back sorting guide 21 as a front / back sorting part, an overflow prevention guide 22, an upper guide 23, a direction change guide 24 as a direction change part, a receiving tray 25 as a collecting part, and a base 26.

[0054] As shown in Figure 4, the outer cylinder 10 extends vertically. Specifically, the outer cylinder 10 extends straight vertically along a vertical axis. The outer cylinder 10 has a cylindrical shape with a central axis O extending vertically. The axial direction of the outer cylinder 10 is the direction in which the central axis O extends, i.e., the vertical direction.

[0055] The outer cylinder 10 includes an outer surface 11 and an inner surface 12. The outer surface 11 is the surface of the outer cylinder 10 that is farther away from the central axis O (outer peripheral side). The inner surface 12 is the surface of the outer cylinder 10 that is closer to the central axis O (inner peripheral side). The side that is farther away from the central axis O than the outer cylinder 10 (outer peripheral side) is referred to as the outer surface 11 side. The side that is closer to the central axis O than the outer cylinder 10 (inner peripheral side) is referred to as the inner surface 12 side.

[0056] FIG. 5 shows the inner surface 12 side of the outer cylinder 10. A plurality of magnets 13 are arranged on the inner surface 12 side of the outer cylinder 10. The plurality of magnets 13 are arranged on the inner surface 12 side of the outer cylinder 10 in a spiral shape having a central axis O extending vertically (in the axial direction of the outer cylinder 10) (hereinafter, the spiral formed by the arrangement of the plurality of magnets 13 will be referred to as a "spiral C"). In this example, the direction of the spiral C is left-handed (S-winding). In this example, the central axis O of the spiral C and the central axis O of the outer cylinder 10 are concentric with each other. The plurality of magnets 13 exert a magnetic field on the outer surface 11 side of the outer cylinder 10, causing the nut N to be attracted to the outer surface 11 of the outer cylinder 10.

[0057] The shaft 14 is housed on the inner surface 12 side of the outer cylinder 10. The shaft 14 is cylindrical with a central axis O extending vertically. A gap is provided between the outer surface 14a of the shaft 14 and the inner surface 12 of the outer cylinder 10. The shaft 14 holds a plurality of magnets 13 arranged in a spiral shape. Specifically, the plurality of magnets 13 are fixed to the shaft 14 by, for example, welding or adhesive. Alternatively, a groove may be provided in the outer surface 14a of the shaft 14, and the magnets 13 may be fitted into the groove.

[0058] The magnet 13 is composed of a pair of small magnets 13a, 13b arranged vertically. In the magnet 13, the pair of small magnets 13a, 13b are adjacent to each other with their opposite magnetic poles facing the outer tube 10 (toward the outer periphery). The pair of small magnets 13a, 13b are arranged vertically. The upper small magnet 13a has its north pole facing the outer tube 10. The lower small magnet 13b has its south pole facing the outer tube 10. A strong local magnetic field is formed at the midpoint 13c of the pair of small magnets 13a, 13b. The nut N is likely to be attracted to the position corresponding to the midpoint 13c on the outer surface 11 of the outer tube 10. Note that in the magnet 13, the pair of small magnets 13a, 13b with their same magnetic poles facing the outer tube 10 (toward the outer periphery) may also be adjacent to each other.

[0059] The rotation axis of motor 15 is connected to the lower end of shaft 14. Motor 15 rotates shaft 14 around central axis O. The rotation direction of motor 15 (shaft 14) is clockwise when viewed from below (the direction of arrow 15a in FIG. 5) (hereinafter simply referred to as clockwise). Motor 15 is, for example, an electric motor.

[0060] The shaft 14 and the motor 15 rotate the multiple magnets 13 around the central axis O. Specifically, the shaft 14 holds the multiple magnets 13 in a spiral arrangement (having the central axis O extending vertically). The motor 15 rotates the shaft 14 around the central axis O. As a result, the multiple magnets 13 rotate around the central axis O.

[0061] As shown in Fig. 4, the restriction guide 16 extends vertically (axially). The restriction guide 16 includes a first guide portion 17 and a second guide portion 18. The first guide portion 17 is provided on the outer surface 11 of the outer cylinder 10 from the vertical middle portion to the lower end portion. The first guide portion 17 protrudes from the outer surface 11 of the outer cylinder 10 toward the outer periphery and extends vertically.

[0062] Similar to the first guide portion 17, the second guide portion 18 protrudes radially outward from the outer surface 11 of the outer cylinder 10 and extends vertically. The second guide portion 18 is located above the first guide portion 17. The second guide portion 18 is disposed slightly offset clockwise relative to the first guide portion 17 in the circumferential direction (rotational direction). Specifically, the lower end of the second guide portion 18 overlaps the upper end of the first guide portion 17. The lower end of the second guide portion 18 is connected to the side surface of the upper end of the first guide portion 17 on the clockwise side in the circumferential direction (the right side in FIG. 4 ).

[0063] The restricting guide 16 restricts the rotational movement of the nut N, causing the nut N to move axially upward along the outer surface 11 of the outer cylinder 10. As shown in FIG. 5 , the nut N is first attracted to the outer surface 11 of the outer cylinder 10 by the first magnet 13A. As the first magnet 13A rotates clockwise around the central axis O, the nut N attempts to rotate clockwise in the circumferential direction along the outer surface 11 of the outer cylinder 10. However, the restricting guide 16 restricts the nut N from rotating clockwise in the circumferential direction. In other words, even though the first magnet 13A rotates, the nut N does not rotate.

[0064] Because the multiple magnets 13 are arranged in a spiral, as the multiple magnets 13 rotate and move, second magnets 13B, third magnets 13C, fourth magnets 13D, ... which are located upstream of first magnet 13A in the rotational direction (counterclockwise circumferentially) appear one after another axially above nut N. As a result, nut N is attracted in turn by second magnet 13B, third magnet 13C, fourth magnet 13D, ... which appear one after another, and moves axially upward along outer surface 11 of outer cylinder 10.

[0065] As shown in FIG. 4, the position change guide 19 is provided on the lower part of the outer surface 11 of the outer cylinder 10. The position change guide 19 is made of a substantially triangular plate-like member. As shown in FIG. 8, the position change guide 19 is bent to correspond to the curved shape of the outer surface 11 of the outer cylinder 10. The position change guide 19 covers a part of the outer surface 11 of the outer cylinder 10 with a predetermined gap H. The position change guide 19 is fixed to the side surface on the counterclockwise side (left side in FIGS. 4 and 8) of the lower part of the first guide part 17 of the restriction guide 16. The gap H between the position change guide 19 and the outer surface 11 of the outer cylinder 10 is larger than the overall thickness T of the nut N and smaller than the two-face width dimension s.

[0066] The position conversion guide 19 allows a nut N to pass through in a laid-down position (a position in which the front surface N1a or back surface N1b of the weld nut N faces the outer surface 11 of the outer cylinder 10), but does not allow a nut N to pass through in an upright position (a position in which the side surface N1c of the nut N faces the outer surface 11 of the outer cylinder 10). The position conversion guide 19 has a first chamfered portion 19a on its end face on the counterclockwise side in the circumferential direction (the left side in Figs. 4 and 8). The position conversion guide 19 has a second chamfered portion 19b on its end face on the lower side in the axial direction (the lower side in Fig. 4, the front side of the paper in Fig. 8).

[0067] When the nut N in an upright position tries to pass through the position change guide 19 from the counterclockwise circumferential side, the nut N is guided by the first chamfered portion 19a of the position change guide 19 and is knocked down. When the nut N in an upright position tries to pass through the position change guide 19 from below to above in the axial direction, the nut N is guided by the second chamfered portion 19b of the position change guide 19 and is knocked down.

[0068] The position change guide 19 changes the position of the nut N from an upright position to a lying position. The nut N that has been changed to the lying position can pass through the position change guide 19.

[0069] 4 and 8, the stopper guide 20 is disk-shaped and is provided around the entire outer surface 11 of the outer cylinder 10. A notch is formed in the first guide portion 17 of the restriction guide 16, and the stopper guide 20 engages with this notch. The stopper guide 20 is located above the position change guide 19 in the axial direction. The stopper guide 20 is connected to the upper end of the position change guide 19. The stopper guide 20 restricts the nut N from moving upward in the axial direction.

[0070] A through-hole 20a is provided in the stopper guide 20 near the portion where it engages with the first guide portion 17 of the restriction guide 16, passing through the stopper guide 20 in the vertical direction in the axial direction. The through-hole 20a is provided in the stopper guide 20 at a position facing the guide surface of the first guide portion 17 of the restriction guide 16. The through-hole 20a constitutes an alignment guide (hereinafter referred to as alignment guide 20a). The width dimension of the alignment guide 20a is slightly larger than the diagonal dimension e of the nut N. The alignment guide 20a prevents multiple nuts N in a lying position that have passed through the position conversion guide 19 from passing through, and aligns the nuts N vertically in a single row.

[0071] The stopper guide 20 restricts the nut N from moving upward in the axial direction at the lower portion of the outer surface 11 of the outer cylinder 10, and encourages movement in the circumferential clockwise direction. When the nut N comes into contact with the lower surface of the stopper guide 20, its upward axial movement is restricted and it is guided in the circumferential clockwise direction. The nut N located on the counterclockwise side of the position change guide 19 is guided into the position change guide 19 by the stopper guide 20. The nut N passes through the position change guide 19 from the counterclockwise side in the circumferential direction.

[0072] The nut N continues to move clockwise in the circumferential direction along the stopper guide 20 and comes into contact with the first guide portion 17 of the restriction guide 16. The nut N is guided by the first guide portion 17 of the restriction guide 16 and moves upward in the axial direction toward the alignment guide 20a. The same applies to the nut N that has passed through the attitude conversion guide 19 from below in the axial direction.

[0073] As shown in FIG. 4, the front / back sorting guide 21 is L-shaped. The front / back sorting guide 21 includes an attachment portion 21a and a protrusion 21b. In the front / back sorting guide 21, the attachment portion 21a and the protrusion 21b are perpendicular to each other. The attachment portion 21a of the front / back sorting guide 21 extends vertically along the axial direction of the outer tube 10. The protrusion 21b of the front / back sorting guide 21 extends perpendicularly inward toward the outer surface 11 of the outer tube 10. The second guide portion 18 of the regulating guide 16 is provided with a fixing portion 18a that protrudes outward. The attachment portion 21a of the front / back sorting guide 21 is attached to the fixing portion 18a of the second guide portion 18 of the regulating guide 16.

[0074] As shown in Figures 6 and 7, the gap L between the protrusion 21b of the front and back sorting guide 21 and the outer surface 11 of the outer cylinder 10 is smaller than the overall thickness T of the nut N and larger than the thickness t of only the main body N1 of the nut N.

[0075] The front and back sorting guide 21 sorts the front and back of the nut N (which moves upward in the axial direction while being guided by the second guide portion 18 of the regulating guide 16) based on the difference in the protruding thickness (total thickness T and thickness t) from the outer surface 11 of the outer tube 10.

[0076] 6, when the nut N is in a position where the surface N1a faces the outer surface 11 of the outer cylinder 10, it does not come into contact with the protrusion 21b of the front / back sorting guide 21 and passes through the front / back sorting guide 21. At this time, the nut N passes through the front / back sorting guide 21 at an approximately central position between the protrusions N3, N3 adjacent to each other in the radial direction.

[0077] 7, when the back surface N1b (on which the protrusion N3 is provided) of the nut N faces the outer surface 11 of the outer cylinder 10, the nut N is struck by the protrusion 21b of the front / back sorting guide 21 and prevented from passing through the front / back sorting guide 21. The nut N struck by the front / back sorting guide 21 falls into a receiving tray 25 (described later) located axially below.

[0078] In summary, based on the difference in the protruding thickness (total thickness T and thickness t) from the outer surface 11 of the outer tube 10, the front / back sorting guide 21 allows the nut N to pass when the front surface N1a faces the outer surface 11 of the outer tube 10, but repels the nut N and prevents it from passing when the back surface N1b (on which the protrusion N3 is provided) faces the outer surface 11 of the outer tube 10.

[0079] As shown in FIG. 4 , the extrusion prevention guide 22 is provided on the outer surface 11 of the outer cylinder 10, near the front / back sorting guide 21. The extrusion prevention guide 22 extends up and down in the axial direction and is disposed on the counterclockwise circumferential side so as to face the second guide portion 18 of the regulating guide 16. The extrusion prevention guide 22 prevents the nut N, which has passed or is about to pass the front / back sorting guide 21 while being guided by the second guide portion 18 of the regulating guide 16, from extruding in the counterclockwise circumferential direction. The distance between the extrusion prevention guide 22 and the second guide portion 18 of the regulating guide 16 is slightly larger than the two-face width dimension s of the nut N. A gap is provided between the lower end of the extrusion prevention guide 22 and the upper end of the first guide portion 17 of the regulating guide 16.

[0080] 4 and 9, the upper guide 23 is disposed on the outer surface 11 of the outer cylinder 10, axially above the front and back sorting guide 21. The upper guide 23 is formed of a channel member having a groove-shaped cross section. The upper guide 23 extends up and down in the axial direction.

[0081] The upper guide 23 includes a groove bottom wall 23a and groove side walls 23b. The groove side walls 23b extend inward from both widthwise ends of the groove bottom wall 23a. The upper guide 23 covers the outer surface 11 of the outer tube 10 so that the inner surface of the groove bottom wall 23a faces the outer surface 11 of the outer tube 10.

[0082] The space surrounded by the upper guide 23 and the outer surface 11 of the outer cylinder 10 forms a passage for the nut N, which has passed through the front / back sorting guide 21, to move upward in the axial direction. The distance between the groove side walls 23b of the upper guide 23 is larger than the two-face width dimension s of the nut N. The distance between the inner surface of the groove bottom wall 23a of the upper guide 23 and the outer surface 11 of the outer cylinder 10 is larger than the overall thickness T of the nut N. The nut N passes through the upper guide 23 and moves further upward in the axial direction.

[0083] As shown in Figures 4 and 9, the direction change guide 24 is disposed at an upper position G1 on the upper side of the lifting mechanism 2. The direction change guide 24 (upper position G1) is disposed on the outer surface 11 of the outer cylinder 10, above the upper end of the upper guide 23. The direction change guide 24 (upper position G1) is disposed near the upper end of the outer cylinder 10. The direction change guide 24 is constituted by a tubular member having a rectangular cross section. The direction change guide 24 is formed from metal.

[0084] The direction change guide 24 extends downward as it approaches the outer periphery. The base end of the direction change guide 24 is connected to the outer surface 11 of the outer cylinder 10 above the upper end of the upper guide 23. The tip end of the direction change guide 24 is located on the outer periphery side and below the base end of the direction change guide 24.

[0085] The distance between the two side walls 24a of the direction change guide 24 (facing each other in the circumferential direction of the outer cylinder 10) is larger than the two-face width dimension s of the nut N. The distance between the upper wall 24b and the lower wall 24c of the direction change guide 24 (facing each other diagonally above and below) is larger than the overall thickness T of the nut N.

[0086] An introduction port 24d configured as a notch is formed in the base end (closer to the outer surface 11 of the outer cylinder 10) of the bottom wall 24c of the direction change guide 24. The introduction port 24d of the direction change guide 24 faces the outer surface 11 of the outer cylinder 10. The width of the introduction port 24d (in the direction perpendicular to the plane of FIG. 9) is greater than the two-face width dimension s of the nut N. The depth of the introduction port 24d (in the diagonal up-down, left-right directions of FIG. 9) is greater than the overall thickness T of the nut N. A gap may be formed between the upper end of the upper guide 23 and the introduction port 24d of the direction change guide 24. A chute 3 is connected to the tip of the direction change guide 24. The chute 3 will be described later.

[0087] The direction changing guide 24 changes the direction of the nut N, which moves upward along the outer surface 11 of the outer cylinder 10, downward at the upper position G1. Specifically, the nut N, which moves upward along the outer surface 11 of the outer cylinder 10 while being guided by the upper guide 23 (with the surface N1a facing the outer surface 11 of the outer cylinder 10), is introduced into the introduction port 24d of the direction changing guide 24 at the upper position G1 and then comes into contact with the upper wall 24b of the direction changing guide 24, thereby being changed in direction radially outward and downward. The surface N1a of the nut N faces the lower wall 24c of the direction changing guide 24. A protrusion N3 provided on the back surface N1b of the nut N faces the upper wall 24b of the direction changing guide 24. The nut N moves radially outward and downward in the direction changing guide 24 due to gravity.

[0088] As shown in FIG. 2, the tray 25 is disposed at a lower position G2 at the lower end of the lifting mechanism 2. The lower position G2 is lower than the upper position G1. In other words, the upper position G1 is higher than the lower position G2. The tray 25 (lower position G2) is disposed below the posture change guide 19 on the outer surface 11 of the outer cylinder 10. The tray 25 is in the shape of a deep dish that is open upward. The tray 25 is disposed so as to expand toward the outer surface 11 of the outer cylinder 10. In detail, the outer cylinder 10 passes through the center of the tray 25 from top to bottom.

[0089] The tray 25 stores a plurality of nuts N at the lower position G2. The plurality of nuts N are stored in the tray 25 (more specifically, in the region between the tray 25 and the outer surface 11 of the outer cylinder 10) in an unaligned state at the lower position G2. The nuts N stored in the tray 25 are attracted to the outer surface 11 of the outer cylinder 10.

[0090] The base 26 is plate-shaped and is provided at the lowest part of the lifting mechanism 2. The base 26 is placed on a foundation. The motor 15 is placed on the upper surface of the base 26. The outer cylinder 10 is placed on top of the motor 15.

[0091] To summarize the lifting mechanism 2, the lifting mechanism 2 lifts the nut N from the tray 25 at the lower position G2 to the direction change guide 24 at the upper position G1.

[0092] <Shooter> The chute 3 will be described with reference to FIGS.

[0093] Fig. 1 shows a schematic diagram of the chute 3. Fig. 9 shows a cross-sectional view of the chute 3 taken along line IX in Fig. 4. Fig. 10 shows a cross-sectional view of the chute 3 taken along line X in Fig. 9.

[0094] The chute 3 has a cylindrical member 31 and a long plate member 32. The cylindrical member 31 is cylindrical. The cross section of the cylindrical member 31 is rectangular. The cylindrical member 31 is a tube. The cylindrical member 31 is made of resin. The cylindrical member 31 is also called a hose. The cylindrical member 31 is made of a flexible material.

[0095] The cylindrical member 31 is made of, for example, urethane, elastomer, olefin, nylon, fluororesin, polyurethane, polypropylene, vinyl chloride, synthetic rubber, etc. The cylindrical member 31 extends in the length direction.

[0096] The long plate member 32 is disposed inside the cylindrical member 31. The long plate member 32 is plate-shaped. The long plate member 32 is made of metal. The long plate member 32 extends along the length direction of the cylindrical member 31. The long plate member 32 extends from one end to the other end of the cylindrical member 31.

[0097] The length direction of the elongated plate member 32 coincides with the length direction of the cylindrical member 31. The width direction of the elongated plate member 32 substantially coincides with the inner diameter of the cylindrical member 31. The elongated plate member 32 fits into an inner groove 31c provided on the inner surface of the cylindrical member 31.

[0098] The cylindrical member 31 includes a first inner surface 31a and a second inner surface 31b that face each other. A back surface 32a on one side in the thickness direction of the elongated plate member 32 is disposed so as to face the first inner surface 31a of the cylindrical member 31. A gap is formed between a surface 32b on the other side in the thickness direction of the elongated plate member 32 and the second inner surface 31b of the cylindrical member 31.

[0099] The long plate member 32 is made of a material harder than the material making up the cylindrical member 31. The long plate member 32 is made of a material that is elastically deformable. For example, carbon steel, stainless steel, aluminum, copper, etc. can be used as the long plate member 32. It is preferable to use SUS301 CSP3 / 4H as the long plate member 32.

[0100] The nut N passes through the interior of the cylindrical member 31. A surface N1a of the nut N faces the second inner surface 31b of the cylindrical member 31. A back surface N1b of the nut N faces the first inner surface 31a of the cylindrical member 31 via the long plate member 32. The nut N slides on the surface 32b of the long plate member 32. Specifically, the protrusion N3 of the nut N slides on the surface 32b of the long plate member 32. The screw hole N2 of the nut N is perpendicular to the conveyance direction of the nut N passing through the cylindrical member 31 (the longitudinal direction of the cylindrical member 31).

[0101] The chute 3 (cylindrical member 31 and long plate member 32) extends downward from the direction change guide 24 (upper position G1) of the lifting mechanism 2 to the supply mechanism 4. On its way downward from the direction change guide 24 (upper position G1) of the lifting mechanism 2 to the supply mechanism 4, the chute 3 may snake back and forth or left and right, rotate around in a spiral, or twist.

[0102] The chute 3 does not return upward (does not snake upward) on the way downward from the direction change guide 24 (upper position G1) of the lifting mechanism 2 to the supply mechanism 4. The chute 3 extends downward from the direction change guide 24 (upper position G1) of the lifting mechanism 2 to the supply mechanism 4 without returning upward. The downstream end of the chute 3 is connected to the nut receiving chamber 66 of the nut receiver 60 in the supply mechanism 4 via a connecting pipe 5.

[0103] The chute 3 drops the nuts N sent from the direction change guide 24 (upper position G1) of the lifting mechanism 2 downward to the supply mechanism 4 without returning them upward.

[0104] <Supply mechanism> (Supply mechanism configuration) The configuration of the supply mechanism 4 will be described with reference to FIGS.

[0105] In the following description, the left-right direction in FIG. 11 is the front-rear direction (indicated by X), the up-down direction in FIG. 11 is the up-down direction (indicated by Z), and the direction perpendicular to the plane of the paper in FIG. 11 is the left-right direction (indicated by Y). The left in FIG. 11 is the front (indicated by X1), and the right in FIG. 11 is the rear (indicated by X2). The top in FIG. 11 is the top (indicated by Z1), and the bottom in FIG. 11 is the bottom (indicated by Z2). The front of the plane of the paper in FIG. 11 is the left, and the back of the plane of the paper in FIG. 11 is the right. As shown in FIG. 1, in reality, the front-rear direction and the left-right direction are inclined with respect to the horizontal plane, from rear to front and from top to bottom.

[0106] 11 to 14 are front views (partially in cross section) of the supply mechanism 4 as seen from the left. Details will be described later, but FIGS. 11 to 14 show different states of the supply mechanism 4. The supply mechanism 4 supplies a nut N to a target position J (between the lower electrode 104 and the upper electrode 109 of the resistance welding machine 100; see also FIG. 1).

[0107] As shown in FIG. 11, the supply mechanism 4 includes a rod 40, a piston 50, a cylinder 51, a lid 52, an actuator 53, a nut receiver 60 as a part receiver, a check valve 70, a sealing mechanism 80, and a connecting member 90.

[0108] Fig. 16 shows a plan view of the rod 40 as seen from above. As shown in Fig. 16, the rod 40 is formed in a rod shape. The axial direction of the axis of the rod 40 extends in the front-to-rear direction. The rod 40 includes a front end portion 41 and a rear portion 42.

[0109] The front end portion 41 constitutes the front end of the rod 40 and a portion slightly rearward from the front end. In the rod 40, the rear portion 42 continues rearward from the front end portion 41. The rear portion 42 extends rearward from the front end portion 41. The rear portion 42 constitutes the rear portion of the rod 40 other than the front end portion 41. The outer diameter of the front end portion 41 is smaller than the outer diameter of the rear portion 42. Conversely, the outer diameter of the rear portion 42 is larger than the outer diameter of the front end portion 41.

[0110] A stepped surface 43 is formed between the front end portion 41 and the rear portion 42 of the rod 40. The stepped surface 43 faces forward. The outer diameter of the front end portion 41 is smaller than the inner diameter of the screw hole N2 of the nut N. The outer diameter of the rear portion 42 is larger than the inner diameter of the screw hole N2 of the nut N.

[0111] The rod 40 includes an air outlet 44 as a gas outlet, an air inlet 45 as a gas inlet, and an air passage 46 as a gas passage.

[0112] The air outlet 44 is provided on the outer periphery 47 of the front end 41 of the rod 40. There may be multiple air outlets 44. The air outlet 44 faces the outer periphery and rearward, i.e., diagonally rearward. It is preferable that the air outlet 44 faces upward and rearward. The air outlet 44 faces the step surface 43.

[0113] The air inlet 45 is provided on the outer periphery 47 of the rod 40, rearward of the air outlet 44. The air inlet 45 is positioned rearward of the air outlet 44. The air inlet 45 is provided on the outer periphery 47 of the rear end of the rear portion 42 of the rod 40. The air inlet 45 faces the outer periphery side. In this example, the air inlet 45 faces upward.

[0114] The air passage 46 is provided in the interior 40a of the rod 40. The air passage 46 extends in the front-rear direction within the interior 40a of the rod 40. The air passage 46 extends in the front-rear direction within the interiors 40a of the front end portion 41 and the rear portion 42 of the rod 40. The air passage 46 connects the air outlet 44 and the air inlet 45 to each other.

[0115] As the rod 40 advances in the axial direction (lengthwise direction), the front end 41 of the rod 40 is inserted into the threaded hole N2 of the nut N. As a result, the nut N is hung on the front end 41 of the rod 40. As the rod 40 advances further, the nut N hung on the front end 41 of the rod 40 is supplied to the destination position J. In summary, the rod 40 supplies the nut N having the threaded hole N2 to the destination position J by advancing.

[0116] As shown in FIG. 11 , the piston 50 is connected to the rear end (of the rear portion 42) of the rod 40 via a connecting member 90, which will be described later. The piston 50 is formed in a substantially disk shape. The axis of the piston 50 extends in the front-to-rear direction. The piston 50 is concentric with the rod 40. The rod 40 extends forward from the piston 50. The rod 40 and the piston 50 move forward and backward together. The outer diameter of the piston 50 is equal to the inner diameter of the cylinder 51.

[0117] The connecting member 90 is also referred to as a joint. The connecting member 90 is formed in a substantially cylindrical shape. The outer diameter of the connecting member 90 is smaller than the outer diameter of the piston 50 (the inner diameter of the cylinder 51). The outer diameter of the connecting member 90 is slightly larger than the outer diameter of the rod 40 (at the rear portion 42). The connecting member 90 is disposed between the rod 40 and the piston 50, i.e., behind the rod 40 and in front of the piston 50. The connecting member 90 connects the rod 40 and the piston 50 to each other. The connecting member 90 moves back and forth integrally with the rod 40 and the piston 50.

[0118] The cylinder 51 is substantially cylindrical. The axis of the cylinder 51 extends in the front-to-rear direction. The cylinder 51 accommodates the rod 40 and the piston 50 inside. The cylinder 51 is concentric with the rod 40 and the piston 50. The front end of the cylinder 51 is open. The rear end of the cylinder 51 is open.

[0119] The lid 52 includes a main body portion 52a and a fitting portion 52b. The main body portion 52a forms the front portion of the lid 52. The main body portion 52a is generally cylindrical. The fitting portion 52b forms the rear portion of the lid 52. The fitting portion 52b is generally cylindrical. The outer diameter of the fitting portion 52b is smaller than the outer diameter of the main body portion 52a. The fitting portion 52b protrudes rearward from the rear end surface of the main body portion 52a. In the lid 52, the main body portion 52a and the fitting portion 52b are concentric with each other.

[0120] The outer diameter of the main body 52a of the lid 52 is equal to the outer diameter of the cylinder 51. The outer diameter of the fitting portion 52b of the lid 52 is equal to the inner diameter of the cylinder 51. The fitting portion 52b of the lid 52 is fitted into the inner diameter of the front end of the cylinder 51. The fitting portion 52b of the lid 52 is fitted into the interior of the front end of the cylinder 51 through the front end opening of the cylinder 51. A male thread is formed on the outer peripheral surface of the fitting portion 52b of the lid 52. A female thread is formed on the inner peripheral surface of the front end of the cylinder 51.

[0121] The rear end surface of the main body 52a of the lid 52 contacts the front end surface of the cylinder 51. The fitting portion 52b of the lid 52 forms a wall portion that covers the front end opening of the cylinder 51. The fitting portion 52b of the lid 52 closes the front end portion of the cylinder 51.

[0122] The lid 52 is concentric with the rod 40, the piston 50, and the cylinder 51. The lid 52 is disposed forward of the piston 50. The lid 52 closes the cylinder 51 forward of the piston 50.

[0123] A hole 52c is provided in the center of the lid 52. The hole 52c is disposed at the axis of the lid 52. The hole 52c penetrates the lid 52 (from the main body portion 52a to the fitting portion 52b) from front to back. The diameter of the hole 52c is slightly larger than the rear portion 42 of the rod 40. The rod 40, which extends forward from the piston 50, penetrates the hole 52c of the lid 52 from front to back. The gap between the lid 52 and the rod 40 is sealed to prevent air A from leaking from the air chamber R in the cylinder 51 through the hole 52c into the external space E outside the cylinder 51.

[0124] The actuator 53 is a known electric actuator. The actuator 53 is driven electrically. The actuator 53 is configured with, for example, an electromagnetic solenoid, a ball screw mechanism, a linear motor, a servo motor, a stepping motor, or a rack gear motor. The actuator 53 includes an electric mechanism 53a and a drive rod 53b.

[0125] The electric mechanism 53a has a cylindrical housing. The axis of the electric mechanism 53a (housing) extends in the front-to-rear direction. The electric mechanism 53a is connected to the rear end of the cylinder 51. It can be said that the electric mechanism 53a covers the rear end opening of the cylinder 51. The electric mechanism 53a is connected to an external power source.

[0126] The drive rod 53b extends in the front-rear direction. The drive rod 53b protrudes forward from the front end surface of the housing of the electric mechanism 53a. The drive rod 53b is housed inside the cylinder 51. The drive rod 53b is inserted into the cylinder 51 through the rear end opening of the cylinder 51. The drive rod 53b is moved forward and backward by the electrical action of the electric mechanism 53a.

[0127] The front end of the drive rod 53b is connected to the rear surface of the piston 50. The actuator 53 causes the electric mechanism 53a to move the drive rod 53b back and forth, thereby moving the piston 50 and the rod 40 (coupled to the piston 50) back and forth.

[0128] Figure 15 is a perspective view of the nut receiver 60. As shown in Figures 11 and 15, the nut receiver 60 includes a holder 61, a receiver 62, and a door 63. Note that the door 63 is not shown in Figure 15. The nut receiver 60 is disposed forward of the lid 52 and the cylinder 51.

[0129] As shown in Fig. 11, the holder 61 is formed in a cylindrical shape. The holder 61 is concentric with the lid 52 and the cylinder 51. As shown in Fig. 11, the holder 61 includes a main body portion 61a and a fitting portion 61b. The main body portion 61a constitutes the portion of the holder 61 other than the rear end portion. The fitting portion 61b constitutes the rear end portion of the holder 61. The outer diameter of the fitting portion 61b is smaller than the outer diameter of the main body portion 61a.

[0130] The outer diameter of the main body 61a of the holder 61 is equal to the outer diameter of the main body 52a of the lid 52. The outer diameter of the fitting portion 61b of the holder 61 is equal to the inner diameter of the front end portion of the main body 52a of the lid 52. The fitting portion 61b of the holder 61 is fitted into the inner diameter of the front end portion of the main body 52a of the lid 52. A male thread is formed on the outer peripheral surface of the fitting portion 61b of the holder 61. A female thread is formed on the inner peripheral surface of the front end portion of the main body 52a of the lid 52.

[0131] As shown in Figure 15, the receiving portion 62 includes a rear wall 62a and (two) left and right side walls 62b. The rear wall 62a is plate-shaped with thickness in the front-to-rear direction and extends up and down and left and right. The left and right side walls 62b are plate-shaped with thickness in the left and right directions and extend up and down and front and back. The left and right side walls 62b protrude forward from both left and right ends of the rear wall 62a.

[0132] A rod through-hole 64 is provided in the rear wall 62a. The rod through-hole 64 penetrates the rear wall 62a in the front-rear direction. The inner diameter of the rod through-hole 64 is larger than the outer diameter of the rod 40 (the rear portion 42 thereof). The rod through-hole 64 is concentric with the rod 40. The rod 40 passes through the rod through-hole 64 when moving forward and backward.

[0133] In the nut receiver 60, the lower portion protrudes inward more than the upper portion on the inner surface of the left and right side walls 62b, forming a step stopper 65. In the nut receiver 60, a nut receiving chamber 66 serving as a parts receiving chamber is formed in the space surrounded by the inner surface of the rear wall 62a and the inner surfaces of the left and right side walls 62b.

[0134] The chute 3 is connected above the nut receiver 60 via a connecting pipe 5. The nuts N sent from the direction change guide 24 (upper position G1) of the lifting mechanism 2 are introduced into the upstream end of the chute 3 in a state where they are aligned so that the protrusions N3 face in a predetermined direction.

[0135] The downstream end of the chute 3 communicates with the nut receiving chamber 66 of the nut receiver 60 via the connecting pipe 5. The connecting pipe 5 is formed in a cylindrical shape with a square cross section. The connecting pipe 5 extends vertically. The lower end of the connecting pipe 5 is connected to the upper end of the rear wall 62a and the upper ends of the left and right side walls 62b of the receiver 62. The downstream end of the chute 3 fits into the inner diameter of the upper end of the connecting pipe 5.

[0136] The connecting pipe 5 includes a groove-shaped groove portion 5a that opens forward, and a lid portion 5b that covers the front opening of the groove portion 5a. The lid portion 5b of the connecting pipe 5 is located forward of the front ends of the left and right side walls 62b of the receiving portion 62.

[0137] The nut receiver 60 receives the nut N sent from the chute 3 through the connecting pipe 5 into the nut receiving chamber 66, with the protrusion N3 facing forward, using the stopper 65. The screw hole N2 of the nut N received by the stopper 65 becomes concentric with the rod through-hole 64 (i.e., with the rod 40). The stopper 65 receives the nut N that has dropped into the nut receiving chamber 66 from the chute 3 (through the connecting pipe 5).

[0138] A discharge hole 67 is provided below the stopper 65 (between the lower portions of the left and right side walls 62b). The discharge hole 67 is provided to discharge a nut N that is smaller (has a smaller diameter) than a nut N of the regular size to the outside when the nut N is mistakenly sent to the nut receiving chamber 66.

[0139] As shown in FIG. 11 , in the nut receiver 60, the door 63 is disposed in front of the nut receiving chamber 66. The door 63 is a plate-like member having a thickness in the front and rear directions, and extends vertically and horizontally. The door 63 covers the nut receiving chamber 66 from the front. Both left and right ends of the lower end of the door 63 are attached to the lower ends of the left and right side walls 62b by hinges (not shown). A spring (not shown) is provided in the hinge. The spring biases the door 63 rearward (in the closing direction). The spring is, for example, a coil spring or a leaf spring.

[0140] When no forward pressing force is applied to the door 63, the door 63 is closed backward by the restoring force of the spring. When a forward pressing force is applied to the door 63, the door 63 is opened forward against the rearward restoring force (in the closing direction) of the spring.

[0141] As shown in Figure 11, the piston 50, cylinder 51, and lid 52 define an air chamber R as a gas chamber. Air A as a gas is stored in the air chamber R. When the piston 50 moves forward, the volume of the air chamber R decreases, and the air A in the air chamber R is compressed. When the piston 50 moves backward, the volume of the air chamber R increases, and the air A in the air chamber R expands.

[0142] The air inlet 45 of the rod 40 faces the air chamber R. The air inlet 45 is disposed inside the air chamber R. Air A is introduced from the air chamber R into the air inlet 45.

[0143] The air passage 46 of the rod 40 extends in the front-rear direction inside the interior 40a of the rod 40 and connects the air outlet 44 and the air inlet 45. Air A passes through the air passage 46 from the air inlet 45 to the air outlet 44.

[0144] As shown in Figure 16, the air outlet 44 of the rod 40 does not face the air chamber R. The air outlet 44 is located outside the air chamber R. The air outlet 44 is located forward of the lid 52. The air outlet 44 is provided on the outer periphery 47 of the front end 41 of the rod 40. The air outlet 44 faces the outer periphery and rearward, i.e., diagonally rearward. The air outlet 44 faces a step surface 43 between the front end 41 and the rear portion 42 of the rod 40.

[0145] The front-to-rear length of the front end portion 41 of the rod 40 is greater than the thickness t of the main body N1 of the nut N. Specifically, the front-to-rear distance from the air outlet 44 to the step surface 43 at the front end portion 41 of the rod 40 is greater than the thickness t of the main body N1 of the nut N.

[0146] Air A is blown out from the air outlet 44. The air A is blown out toward the outer periphery and rearward, i.e., diagonally rearward, from the air outlet 44. The air A is blown out from the air outlet 44 toward the step surface 43 between the front end 41 and the rear portion 42 of the rod 40.

[0147] As will be described in more detail later, air A blown out from the air outlet 44 at the front end 41 of the rod 40 presses the nut N (hanging on the front end 41 of the rod 40) against the step surface 43 between the front end 41 and the rear portion 42 of the rod 40.

[0148] Returning to FIG. 11 , the check valve 70 is also called a check valve. As described above, the piston 50, the cylinder 51, and the lid 52 define the air chamber R. The air chamber R is disposed within the cylinder 51. A communication passage (not shown) that communicates the air chamber R within the cylinder 51 with the external space E outside the cylinder 51 is provided in the cylindrical wall of the cylinder 51. The check valve 70 controls the flow of air A between the air chamber R within the cylinder 51 and the external space E outside the cylinder 51 (communication passage).

[0149] The check valve 70 allows air A to flow from the external space E outside the cylinder 51 into the air chamber R inside the cylinder 51, while restricting the outflow of air A from the air chamber R inside the cylinder 51 to the external space E outside the cylinder 51. Air A can flow from the external space E into the air chamber R via the check valve 70. Air A cannot flow from the air chamber R to the external space E via the check valve 70.

[0150] 11, the sealing mechanism 80 is provided on the rod 40. The sealing mechanism 80 includes a bushing 81 and a coil spring 82 as a biasing member. The sealing mechanism 80 is disposed in the air chamber R.

[0151] FIG. 17 shows the sealing mechanism 80 in a side view. FIG. 18 shows the sealing mechanism 80 in a front view (partial cross section). The bushing 81 is made of rubber. As shown in FIGS. 11, 17, and 18, the bushing 81 is formed in a cylindrical shape. The axis of the bushing 81 extends in the front-to-rear direction. The bushing 81 is hung on the rod 40. More specifically, the bushing 81 is hung on the outer periphery 47 of the rear portion 42 of the rod 40. The bushing 81 is concentric with the rod 40.

[0152] The bushing 81 is disposed inside the cylinder 51. The bushing 81 is disposed forward of the piston 50. The bushing 81 is disposed rearward of the lid 52. The bushing 81 is disposed in the air chamber R.

[0153] The bushing 81 is fitted onto (the rear portion 42 of) the rod 40. The inner diameter of the bushing 81 is fitted onto the outer diameter of (the rear portion 42 of) the rod 40. The inner diameter of the bushing 81 is slightly smaller than, approximately equal to, or slightly larger than the outer diameter of (the rear portion 42 of) the rod 40. The outer diameter of the bushing 81 is smaller than the inner diameter of the cylinder 51.

[0154] When no forward or backward pressing force is applied to the bush 81, the bush 81 moves forward or backward integrally with the rod 40. When a forward or backward pressing force is applied to the bush 81, the bush 81 can move forward or backward relative to the rod 40.

[0155] The coil spring 82 is in the form of a coil. The outer shape of the coil spring 82 is cylindrical. The coil spring 82 is wound around the rod 40. Specifically, the coil spring 82 is wound around the outer periphery 47 of the rear portion 42 of the rod 40. The coil spring 82 extends in the front-to-rear direction. The coil spring 82 is concentric with the rod 40. The diameter of the coil spring 82 is larger than the inner diameter of the bushing 81 and smaller than the outer diameter of the bushing 81.

[0156] The coil spring 82 is disposed rearward of the bushing 81. The coil spring 82 is wound around the rod 40 rearward of the bushing 81.

[0157] The coil spring 82 is disposed forward of the connecting member 90 (disposed forward of the piston 50). The coil spring 82 is wound around the rod 40 forward of the piston 50. More specifically, the coil spring 82 is wound around the rod 40 forward of the connecting member 90 (disposed forward of the piston 50).

[0158] The front end of the coil spring 82 is connected to the rear end surface of the bushing 81. The rear end of the coil spring 82 is connected to the front end surface of the connecting member 90. The coil spring 82 connects the bushing 81 and the connecting member 90 in the front-rear direction.

[0159] The coil spring 82 holds the bushing 81 on (the rear portion 42 of) the rod 40 via the connecting member 90. When the coil spring 82 is at its natural length, the front end of the coil spring 82 is located forward of the air inlet port 45. In other words, when the coil spring 82 is at its natural length, the bushing 81 is located forward of the air inlet port 45. At this time, the air inlet port 45 is opened.

[0160] The coil spring 82 exerts a restoring force F as a biasing force on the bushing 81 in the forward direction (see FIG. 18). The coil spring 82 biases the bushing 81 forward so as to move it away from the air inlet port 45. When the coil spring 82 is at its natural length, the forward restoring force F is zero.

[0161] The bushing 81 comes into contact with the lid 52 by following the forward movement of the rod 40. After coming into contact with the lid 52, the bushing 81 moves rearward relative to the rod 40 against the forward restoring force F from the coil spring 82 to the bushing 81 due to a rearward pressing force P from the lid 52 to the bushing 81, thereby closing the air inlet port 45.

[0162] As the rod 40 advances, it supplies the nut N to the target position J, and at the same time, the bush 81 closes the air inlet 45 .

[0163] In order to simultaneously achieve the operation of supplying the nut N to the target position J and the operation of the bush 81 blocking the air inlet 45, the front-to-rear dimension of the rod 40, the position of the air inlet 45 on the rod 40, the front-to-rear dimension of the bush 81, the front-to-rear dimension of the coil spring 82, the positional relationship between the bush 81 and the air inlet 45 when the coil spring 82 is at its natural length, the spring constant of the coil spring 82, etc. are appropriately set.

[0164] The supply mechanism 4 receives the nut N that has dropped from the chute 3 (via the connecting pipe 5) into the nut receiving chamber 66 with the stopper 65, and supplies the nut N received by the stopper 65 to the target position J by the forward movement of the rod 40.

[0165] (Nut supply by supply mechanism) The supply of nuts N by the supply mechanism 4 will be described mainly with reference to Figures 11 to 14. Figure 11 shows a front view (partially in cross section) of the supply mechanism 4 before the rod 40 is inserted into the screw hole N2 of the nut N. Figure 12 shows a front view (partially in cross section) of the supply mechanism 4 after the rod 40 has been inserted into the screw hole N2 of the nut N. Figure 13 shows a front view (partially in cross section) of the supply mechanism 4 at the moment when the rod 40 supplies the nut N to the destination position J. Figure 14 shows a front view (partially in cross section) of the supply mechanism 4 after the rod 40 has retracted from the destination position J.

[0166] 11 shows the state before the front end 41 of the rod 40 is inserted into the threaded hole N2 of the nut N. At this time, the actuator 53 retracts the drive rod 53b to the rear as far as possible by the electrical action of the electric mechanism 53a. The piston 50, the connecting member 90, and the rod 40 are all retracted to the rear as far as possible.

[0167] The front end portion 41 of the rod 40 is disposed within the holder 61 of the nut receiver 60. The front end portion 41 of the rod 40 is disposed rearward of the nut receiving chamber 66 of the receiving portion 62 of the nut receiver 60. In detail, the front end portion 41 of the rod 40 is disposed rearward of the rod through-hole 64 in the rear wall 62a of the receiving portion 62 of the nut receiver 60.

[0168] The nut N sent from the chute 3 to the nut receiving chamber 66 via the connecting pipe 5 is caught (received) by the stopper 65 of the nut receiver 60. The nut N is placed in the nut receiving chamber 66 with the protrusion N3 facing forward and caught by the stopper 65. In this way, in the supply mechanism 4, the stopper 65 receives the nut N that has dropped into the nut receiving chamber 66 from the chute 3 (via the connecting pipe 5).

[0169] The door 63 is closed rearward by the restoring force of a spring attached to the hinge, and covers the nut receiving chamber 66 from the front.

[0170] The volume of the air chamber R defined by the piston 50, the cylinder 51, and the lid 52 is maximized. The air chamber R is filled with air A. The air A in the air chamber R is expanded to its maximum. The air inlet 45 (in the rear part 42) of the rod 40 faces the air chamber R (is disposed within the air chamber R). The air A still remains in the air chamber R and has not yet been introduced into the air inlet 45.

[0171] As described above, the sealing mechanism 80 is provided on the rod 40 in the air chamber R. The sealing mechanism 80 includes a bushing 81 and a coil spring 82. The coil spring 82 is at its natural length. The bushing 81 (connected to the front end of the coil spring 82) is located forward of the air inlet port 45 of the rod 40. The coil spring 82 urges the bushing 81 forward by a restoring force F so as to move the bushing 81 away from the air inlet port 45. However, because the coil spring 82 is at its natural length, the forward restoring force F from the coil spring 82 to the bushing 81 is zero. The bushing 81 is fitted into the rod 40. The bushing 81 also moves forward in response to the forward movement of the rod 40.

[0172] 12 shows the state after the front end 41 of the rod 40 has been inserted into the threaded hole N2 of the nut N. At this time, the actuator 53 pushes the drive rod 53b forward by the electrical action of the electric mechanism 53a. The piston 50, the connecting member 90, and the rod 40 move forward.

[0173] The front end 41 of the rod 40 is positioned in the nut receiving chamber 66 of the nut receiver 60. The front end 41 of the rod 40 enters the nut receiving chamber 66 through the rod through-hole 64 in the rear wall 62a. The front end 41 of the rod 40 is inserted into the screw hole N2 of the nut N (which is hooked (received) by the stopper 65 in the nut receiving chamber 66). The nut N is hung on the front end 41 of the rod 40.

[0174] When the rod 40 moves forward, a step surface 43 between the front end 41 and the rear end 42 of the rod 40 comes into contact with the rear end surface of the nut N. An air outlet 44 on an outer periphery 47 of the front end 41 of the rod 40 is located forward of the front end surface of the nut N.

[0175] With the nut N engaged, the front end 41 of the rod 40 pushes the door 63 forward. The front end 41 of the rod 40 applies a forward pressing force to the door 63, causing the door 63 to open forward against the restoring force of the spring toward the rear (in the closing direction).

[0176] A part of the rear portion 42 of the rod 40 is located forward of the rod through-hole 64 and is positioned in the nut receiving chamber 66. The next nut N to be sent from the chute 3 through the connecting pipe 5 to the nut receiving chamber 66 is placed on the upper part of the rear portion 42 of the rod 40 located in the nut receiving chamber 66.

[0177] As the piston 50 advances, the volume of the air chamber R decreases. The air A in the air chamber R is compressed. The compressed air A is introduced from the air chamber R into the air inlet 45 on the outer periphery 47 of the rear part 42 of the rod 40.

[0178] The air A introduced into the air inlet 45 moves from rear to front through the air passage 46 in the interior 40a of the rod 40 and is blown out from the air outlet 44. Specifically, the air A is blown out from the air outlet 44 toward the outer periphery and rearward, i.e., diagonally rearward. More specifically, the air A is blown out from the air outlet 44 toward the step surface 43 between the front end 41 and the rear portion 42 of the rod 40. As described above, the air outlet 44 is located forward of the front end surface of the nut N.

[0179] The air A blown out from the air outlet 44 at the front end 41 of the rod 40 presses the nut N (hanging on the front end 41 of the rod 40) against the step surface 43 between the front end 41 and the rear part 42 of the rod 40. This causes the nut N to be firmly held on the front end 41 of the rod 40.

[0180] The nut N hung on the front end portion 41 of the rod 40 has not yet been supplied to (reached) the target position J.

[0181] A communication passage (not shown) that communicates the air chamber R inside the cylinder 51 with the external space E outside the cylinder 51 is provided in the cylindrical wall of the cylinder 51. The check valve 70 controls the flow of air A between the air chamber R inside the cylinder 51 and the external space E outside the cylinder 51 (communication passage).

[0182] The check valve 70 regulates (blocks or inhibits) the outflow of air A from the air chamber R in the cylinder 51 to the external space E outside the cylinder 51. The air A compressed in the air chamber R does not flow out into the external space E outside the cylinder 51 via the check valve 70.

[0183] The coil spring 82 is still at its natural length. The forward restoring force F from the coil spring 82 to the bushing 81 is still zero. The bushing 81 is located forward of the air inlet port 45. The bushing 81 moves forward in response to the forward movement of the rod 40.

[0184] Figure 13 shows the state at the moment when the rod 40 supplies the nut N to the destination position J. Figure 18 shows the state of the sealing mechanism 80 at the moment when the rod 40 supplies the nut N to the destination position J. The actuator 53 further pushes the drive rod 53b forward by the electrical action of the electric mechanism 53a. The piston 50, the connecting member 90, and the rod 40 move further forward.

[0185] The nut N hung on the front end 41 of the rod 40 is supplied (reaches) the target position J. In this way, in the supply mechanism 4, the nut N received by the stopper 65 is supplied to the target position J by the forward movement of the rod 40.

[0186] The bushing 81 attempts to move forward by itself, following the forward movement of the rod 40. However, the lid 52 is disposed in front of the bushing 81. As the bushing 81 follows the forward movement of the rod 40, it comes into contact with the rear end surface of the lid 52. In detail, as the bushing 81 moves forward by itself, following the forward movement of the rod 40, it comes into contact with the rear end surface of the lid 52.

[0187] After the bushing 81 comes into contact with the lid 52, a rearward pressing force P acts from the lid 52 on the bushing 81. As the rearward pressing force P acts from the lid 52 on the bushing 81, the coil spring 82 (connected to the bushing 81) contracts from its natural length. A forward restoring force F acts from the coil spring 82 on the bushing 81. Due to the rearward pressing force P from the lid 52 on the bushing 81, the bushing 81 moves rearward relative to the rod 40 against the forward restoring force F from the coil spring 82 on the bushing 81. In other words, the bushing 81 that has come into contact with the lid 52 does not move forward, but the rod 40 moves forward. The bushing 81 that moves rearward relative to the rod 40 blocks the air inlet port 45.

[0188] The bushing 81 of the sealing mechanism 80 closes the air inlet 45 of the rod 40 , thereby sealing off the flow of air A from the air chamber R to the air inlet 45 .

[0189] In summary, after the bushing 81 comes into contact with the lid 52, the rearward pressing force P from the lid 52 on the bushing 81 causes the bushing 81 to move rearward relative to the rod 40 against the forward restoring force F from the coil spring 82 on the bushing 81, thereby blocking the air inlet 45.

[0190] As the rod 40 advances, it supplies the nut N to the target position J, and at the same time, the bush 81 closes the air inlet 45 .

[0191] As the piston 50 advances further, the volume of the air chamber R becomes smaller. The air A in the air chamber R is further compressed. However, the bushing 81 blocks the air inlet 45. Therefore, the compressed air A is not introduced from the air chamber R into the air inlet 45.

[0192] Since air A is no longer introduced into air inlet 45, air A no longer moves through air passage 46 and is no longer blown out from air outlet 44. Air A is no longer blown out from air outlet 44 toward nut N hung on front end 41 of rod 40. Nut N hung on front end 41 of rod 40 is no longer pressed against step surface 43 of rod 40. The hold of nut N by front end 41 of rod 40 is released.

[0193] At the target position J, the nut N is removed from the front end portion 41 of the rod 40. The removed nut N is placed between the lower electrode 104 and the upper electrode 109 of the resistance welding machine 100, which serves as the target position J.

[0194] The air A compressed in the air chamber R does not flow out into the external space E outside the cylinder 51 through the check valve 70.

[0195] 14 shows the state after the rod 40 has retreated (retracted) from the target position J. The actuator 53 retracts the drive rod 53b rearward by the electrical action of the electric mechanism 53a. The piston 50, the connecting member 90, and the rod 40 retreat.

[0196] The front end 41 of the rod 40, from which the nut N has been removed at the target position J, retreats (moves back) from the target position J.

[0197] As the rod 40 moves backward, the rearward pressing force P from the lid 52 on the bushing 81 decreases, and the coil spring 82 (connected to the bushing 81) stretches. The forward restoring force F from the coil spring 82 on the bushing 81 causes the bushing 81 to move forward relative to the rod 40. In other words, even though the rod 40 moves backward, the bushing 81 does not move backward. As a result, the bushing 81 moves forward relative to the air inlet port 45. The air inlet port 45 is no longer blocked by the bushing 81, and the air inlet port 45 is opened.

[0198] As rod 40 moves further backward, bushing 81 is released from contact with lid 52, the rearward pressing force P from lid 52 on bushing 81 becomes zero, and coil spring 82 extends to its natural length (returns to its original state). At this time, the forward restoring force F from coil spring 82 on bushing 81 becomes zero. Then, bushing 81 returns to its original position and is positioned forward of air inlet port 45. The blockage of air inlet port 45 by bushing 81 is fully released, and air inlet port 45 is fully opened.

[0199] After the coil spring 82 reaches its natural length, the bushing 81 also moves backward so as to follow the backward movement of the rod 40 (the bushing 81 moves backward integrally with the rod 40).

[0200] As the piston 50 moves backward, the volume of the air chamber R increases. The air A in the air chamber R expands. Although the air inlet 45 is open, the expanded air A is not introduced into the air inlet 45. The air A does not move through the air passage 46 and is not blown out from the air outlet 44.

[0201] The check valve 70 allows (opens) the inflow of air A from the external space E outside the cylinder 51 into the air chamber R inside the cylinder 51. As the volume of the air chamber R increases (as the air A in the air chamber R expands), the air A (atmosphere) in the external space E flows into the air chamber R from the external space E via the check valve 70.

[0202] 11, the front end 41 of the rod 40 is positioned rearward of the nut receiving chamber 66 (rearward of the rod through-hole 64). The next nut N sent from the chute 3 through the connecting pipe 5 to the nut receiving chamber 66 is received and caught by the stopper 65. The door 63 is closed rearward by the restoring force of the spring provided on the hinge.

[0203] Thereafter, the above-mentioned process is repeated.

[0204] <Resistance welding machine> 1, a nut transfer system 1 is applied to a resistance welding machine 100. The nut transfer system 1 and the resistance welding machine 100 constitute a nut welding system S.

[0205] The nut transfer system 1 transfers the nut N to a destination position J. The destination position J is located between a lower electrode 104 and an upper electrode 109, which are a pair of electrodes in the resistance welding machine 100. The destination position J is located below the direction change guide 24 (upper position G1) of the lifting mechanism 2. The destination position J may also be located below the receiving tray 25 (lower position G2).

[0206] The resistance welding machine 100 includes a pair of electrode units, namely, a lower electrode unit 101 and an upper electrode unit 102. As will be described in detail later, the lower electrode unit 101 includes a lower electrode 104, and the upper electrode unit 102 includes an upper electrode 109. That is, the resistance welding machine 100 includes the lower electrode 104 and the upper electrode 109 as a pair of electrodes.

[0207] The resistance welding machine 100 welds a workpiece W and a nut N while sandwiching them between a lower electrode 104 of a lower electrode unit 101 and an upper electrode 109 of an upper electrode unit 102. The workpiece W is, for example, a metal plate-shaped member. The lower electrode unit 101 (lower electrode 104) is fixed in place. The upper electrode unit 102 (upper electrode 109) moves up and down.

[0208] Fig. 19 shows a lower electrode unit 101 of a resistance welding machine 100. As shown in Fig. 19, the lower electrode unit 101 includes a lower holder 103, a lower electrode 104 as an electrode, a guide pin 105, a guide pin actuator 106, and an interposition rod 107. The lower holder 103 is cylindrical and extends vertically. The lower holder 103 is fixed in place.

[0209] The lower electrode 104 is disposed at the upper end of the lower holder 103. The lower electrode 104 covers the upper end of the lower holder 103. The workpiece W is placed on an upper end 104a, which is the tip of the lower electrode 104. The upper end surface of the lower electrode 104 forms a mounting surface on which the workpiece W is placed. The upper end 104a of the lower electrode 104 contacts the lower surface of the workpiece W. A through hole 104b that penetrates vertically is formed in the center of the lower electrode 104.

[0210] The guide pin 105 is rod-shaped and extends vertically. The guide pin 105 moves vertically within the lower holder 103. The guide pin 105 passes through a through-hole 104b in the lower electrode 104, and protrudes upward from an upper end 104a serving as the tip of the lower electrode 104, and retracts downward from the upper end 104a serving as the tip of the lower electrode 104. In other words, the guide pin 105 protrudes upward and retracts downward from the upper end (tip) 104a of the lower electrode 104.

[0211] The guide pin 105 is used to position the nut N. A hole Wa penetrating in the thickness direction (vertical direction) is formed in the workpiece W. The guide pin 105 is inserted from below to above through the hole Wa of the workpiece W (placed on the upper end 104a of the lower electrode 104).

[0212] The upper end of the guide pin 105 (inserted through the hole Wa of the workpiece W) protrudes above the upper surface of the workpiece W placed on the upper end 104a of the lower electrode 104. The screw hole N2 of the nut N supplied by the supply mechanism 4 to the destination position J (between the lower electrode 104 and upper electrode 109 as a pair of electrodes) fits into the upper end of the guide pin 105 (protruding above the upper surface of the workpiece W). The protrusion N3 on the back surface N1b of the nut N faces the upper surface of the workpiece W below. The guide pin 105 positions the nut N on the upper surface of the workpiece W.

[0213] The guide pin actuator 106 is a known retraction actuator and includes a cylinder 106a, a piston 106b, a drive rod 106c, and a coil spring 106d as an elastic member.

[0214] The cylinder 106a is cylindrical. The axis of the cylinder 106a extends vertically. The cylinder 106a is disposed below the lower end of the lower holder 103. The upper and lower ends of the cylinder 106a are closed by upper and lower wall portions. A through hole is formed in the upper wall portion of the cylinder 106a.

[0215] The piston 106b is housed inside the cylinder 106a. The drive rod 106c is housed inside the cylinder 106a. The drive rod 106c is rod-shaped and extends vertically. The lower end of the drive rod 106c is fixed to the upper surface of the piston 106b. The drive rod 106c starts from the upper surface of the piston 106b and extends upward, passes through a through-hole in the upper wall of the cylinder 106a, and extends further upward, protruding to the outside of the cylinder 106a. The upper end of the drive rod 106c is located above (outside) the upper wall of the cylinder 106a. The upper end of the drive rod 106c is inserted into the lower holder 103 from below through an opening in the lower end of the lower holder 103.

[0216] The coil spring 106d is coil-shaped. The coil spring 106d is housed inside the cylinder 106a. Inside the cylinder 106a, the coil spring 106d is disposed below the piston 106b and above the bottom wall of the cylinder 106a. The coil spring 106d pushes the piston 106b and the drive rod 106c upward with an elastic force V serving as a biasing force.

[0217] The intervening rod 107 has a rod-like shape that extends vertically. The intervening rod 107 is disposed (interposed) within the lower holder 103. Within the lower holder 103, the intervening rod 107 is disposed below the guide pin 105 and above the drive rod 106c of the guide pin actuator 106. The intervening rod 107 may connect the lower end of the guide pin 105 and the upper end of the drive rod 106c.

[0218] In the guide pin actuator 106, the coil spring 106d pushes the piston 106b and the drive rod 106c upward with an elastic force (biasing force) V, thereby pushing the guide pin 105 upward via the intervening rod 107.

[0219] In an unloaded state in which no downward load is applied to the guide pin 105, the guide pin 105 protrudes upward from the upper end (tip) 104a of the lower electrode 104 due to an upward elastic force (urging force) V from the coil spring (elastic member) 106d of the guide pin actuator 106. That is, the coil spring (elastic member) 106d of the guide pin actuator 106 urges the guide pin 105 upward (via the piston 106b, the drive rod 106c, and the intervening rod 107) so that the guide pin 105 protrudes upward from the upper end (tip) 104a of the lower electrode 104.

[0220] In a loaded state in which a downward load is applied to the guide pin 105, the guide pin 105 is pressed downward against an upward elastic force (biasing force) V by the coil spring (elastic member) 106d of the guide pin actuator 106, and thereby retracts downward from the upper end (tip) 104a of the lower electrode 104. The downward load on the guide pin 105 is exerted by downward pressure from the upper electrode 109.

[0221] 1, the upper electrode unit 102 includes an upper holder 108, an upper electrode 109 as an electrode, and an upper actuator 110. The upper holder 108 is cylindrical and extends vertically. The upper holder 108 moves vertically.

[0222] The upper electrode 109 is disposed at the lower end of the upper holder 108. The upper electrode 109 covers the lower end of the upper holder 108. When the upper holder 108 moves downward, the lower end 109a as the tip of the upper electrode 109 comes into contact with the surface N1a of the nut N (see FIG. 10).

[0223] The upper actuator 110 is disposed above the upper holder 108. The upper actuator 110 is an electric actuator. The upper actuator 110 is configured with, for example, an electromagnetic solenoid, a ball screw mechanism, a linear motor, a servo motor, a stepping motor, or a rack gear motor. The upper actuator 110 moves the upper holder 108 and the upper electrode 109 up and down by electrical action.

[0224] <Action and effect> According to this embodiment, the nut N is raised from the receiving tray 25 (lower position G2) to the direction change guide 24 (upper position G1) in the lifting mechanism 2, falls downward from the direction change guide 24 (upper position G1) of the lifting mechanism 2 through the chute 3, is received by the stopper 65 of the supply mechanism 4, and is supplied to the target position J by the advancement of the rod 40 of the supply mechanism 4.

[0225] The chute 3 extends downward from the direction change guide 24 (upper position G1) of the lifting mechanism 2 to the supply mechanism 4 without returning upward. The nut N naturally falls downward by gravity in the chute 3 from the direction change guide 24 (upper position G1) of the lifting mechanism 2 to the supply mechanism 4 without returning upward.

[0226] It is possible to reduce (and preferably eliminate) the need for) an air pumping device as a gas pumping device for pumping air A as a gas to move the nut N from below to above against gravity in the chute 3. This reduces the need for an air supply source (such as an air pump as a gas pump) as a gas supply source for supplying air A to such an air pumping device.

[0227] As described above, the air supply source in the nut transfer system 1 that transfers the nut N to the destination position J can be reduced.

[0228] The nut N is attracted to the outer surface 11 of the outer cylinder 10 by some of the multiple magnets 13 arranged in a spiral shape. As the magnets 13 rotate around the central axis O, the nut N attempts to rotate in the circumferential direction along the outer surface 11 of the outer cylinder 10. However, the rotational movement of the nut N is restricted by the restricting guide 16. In other words, even though the magnets 13 rotate, the nut N does not rotate.

[0229] Because the multiple magnets 13 are arranged spirally and the axial direction of the outer cylinder 10 extends up and down, as the multiple magnets 13 rotate and move, second magnets 13B, third magnets 13C, fourth magnets 13D, ... appear one after another upstream in the rotational direction (counterclockwise circumferential direction) of first magnet 13A above the nut N. The nut N is attracted in turn by the second magnets 13B, third magnets 13C, fourth magnets 13D, ... that appear one after another, and moves upward in the axial direction along the outer surface 11 of the outer cylinder 10.

[0230] The lifting mechanism 2 can lift the nut N upward with a simple configuration.

[0231] In the lifting mechanism 2, the front and back sides of the nuts N can be sorted by the front and back sorting guide 21 and converted into a uniform posture.

[0232] In the lifting mechanism 2, the nut N can be suitably lifted upward from the tray 25 located at the lower position G2.

[0233] In particular, with the lifting mechanism 2, the front / back sorting guide 21 and the tray 25 can be seen below the worker's line of sight, making the work easier and safer than when the worker sees them above the worker's line of sight.

[0234] By changing the direction of the nut N from above to below by the direction change guide 24 at the upper position G1 in the lifting mechanism 2, the nut N can be smoothly sent to the chute 3 in the subsequent process while moving downward.

[0235] Furthermore, the use of an air pumping device for pumping air A to change the direction of the nut N from above to below can be suppressed, which contributes to reducing the air supply source.

[0236] In the chute 3, the nut N slides against the long plate member 32 arranged inside the tubular member 31, thereby preventing the nut N from coming into direct contact with the inner surface of the tubular member 31, thereby preventing damage to the tubular member 31.

[0237] Furthermore, since the nut N falls smoothly downward in the chute 3, the use of an air pumping device for pumping the nut N downward in the chute 3 with air A can be reduced, which contributes to reducing the air supply source.

[0238] By bending the flexible cylindrical member 31, the elastically deformable long plate member 32 can also be deformed. Furthermore, because the long plate member 32 is harder than the cylindrical member 31, frictional resistance when the nut N slides against the long plate member 32 can be reduced, making it easier for the nut N to slide against the long plate member 32. Even when the chute 3 is snaked back and forth or left and right, or when the chute 3 is twisted, the nut N can be dropped down the chute 3. A decrease in the dropping speed of the nut N down the chute 3 can be suppressed.

[0239] Furthermore, since the nut N falls smoothly downward in the chute 3, the use of an air pumping device for pumping the nut N downward in the chute 3 with air A can be reduced, which contributes to reducing the air supply source.

[0240] In the chute 3, there is a concern that if the protrusion N3 of the nut N comes into contact with the tubular member 31, the tubular member 31 may be damaged. However, by having the protrusion N3 of the nut N slide against the long plate member 32, the protrusion N3 of the nut N is prevented from coming into direct contact with the inner surface of the tubular member 31, thereby preventing damage to the tubular member 31.

[0241] Furthermore, since the nut N falls smoothly downward in the chute 3, the use of an air pumping device for pumping the nut N downward in the chute 3 with air A can be reduced, which contributes to reducing the air supply source.

[0242] In the supply mechanism 4, the actuator 53 moves the rod 40 back and forth without using an air supply source.

[0243] As the rod 40 advances, the front end 41 of the rod 40 is inserted into the through-hole N2 of the nut N. The nut N hung on the front end 41 of the rod 40 is supplied to the destination position J as the rod 40 advances.

[0244] Air A is stored in air chamber R, which is defined by piston 50, cylinder 51, and lid 52. When piston 50 moves forward, air A in air chamber R is compressed. The air A compressed in air chamber R is introduced into air inlet 45 of rod 40. Air A introduced into air inlet 45 passes through air passage 46 in interior 40a of rod 40 and is blown out from air outlet 44 on outer periphery 47 of front end 41 of rod 40.

[0245] Air A is blown out from air outlets 44 on the outer periphery 47 of the front end 41 of the rod 40 toward the nut N hung on the front end 41 of the rod 40. As a result, the nut N is held on the front end 41 of the rod 40.

[0246] In the supply mechanism 4, an air chamber R partitioned by a piston 50, a cylinder 51, and a lid 52 is utilized, so that the nut N can be held at the front end 41 of the rod 40 by blowing out air A from the air outlet 44 without using an air supply source.

[0247] At the target position J, the guide pin 105 can be protruded and retracted from the upper end (tip) 104a of the lower electrode 104 without using an air supply source.

[0248] The nut welding system S (nut transfer system 1 and resistance welding machine) according to this embodiment can achieve an airless system without an air supply source (particularly, a completely airless system in which no air supply source is required at all can be achieved).

[0249] <Other embodiments> Although the present disclosure has been described above with reference to preferred embodiments, such description is not limiting, and it goes without saying that various modifications, substitutions, or combinations are possible.

[0250] A connecting member may be interposed between the drive rod 53b of the actuator 53 and the piston 50. The piston 50 and the rod 40 may be directly connected to each other without the connecting member 90 being interposed between them.

[0251] The term "tubular" is not limited to cylindrical shapes, but may also include rectangular shapes.

[0252] The lid 52 may not be disposed at the front end of the cylinder 51, but may be disposed at an intermediate portion rearward of the front end of the cylinder 51. The cylinder 51 and the lid 52 may be integrally formed as a single member.

[0253] The rod 40 may have a portion rearward of the rear portion 42 that is smaller in diameter than the rear portion 42 (and further a portion smaller in diameter than the front end portion 41). An air inlet 45 may be provided in the portion with a smaller diameter. The air inlet 45 may be provided not on the outer periphery 47 of the rod 40 but at the rear end of the rod 40, for example.

[0254] The actuator 53 does not have to be an electric actuator, but may be, for example, a hydraulic actuator (hydraulic cylinder mechanism) or a pneumatic actuator (air cylinder mechanism).

[0255] In the lifting mechanism 2, the central axis of the spiral C, the central axis of the shaft 14, and the central axis of the outer cylinder 10 may be eccentric with respect to one another. The outer cylinder 10 may be inclined with respect to the vertical axis.

[0256] The tray 25 does not necessarily have to be provided at the lower position G2 of the lifting mechanism 2, and for example, the nut N may be manually placed at the lower position G2 of the lifting mechanism 2. The direction change guide 24 does not necessarily have to be provided at the upper position G1 of the lifting mechanism 2, and for example, the lifting mechanism 2 may be directly connected to the chute 3 at the upper position G1.

[0257] In the chute 3, the long plate member 32 may be provided only on a part of the chute 3. For example, it may be provided only on the serpentine portion of the chute 3 where the nut N is most likely to come into contact with the cylindrical member 31. In the chute 3, the surface N1a of the nut N, which does not have the protrusion N3, may slide against the long plate member 32. In the chute 3, the long plate member 32 does not have to be made of metal, and may be made of, for example, an elastically deformable hard plastic. In the chute 3, the long plate member 32 may not be provided.

[0258] In the chute 3, the cross section of the cylindrical member 31 is not limited to a square shape, and may be, for example, a circle, a cross shape, a key shape, etc. In the chute 3, the cylindrical member 31 does not have to be made of resin.

[0259] The guide pin actuator 106 does not have to be a retraction actuator, and may be, for example, an electric actuator (electric cylinder mechanism), a hydraulic actuator (hydraulic cylinder mechanism), a pneumatic actuator (air cylinder mechanism), etc. The elastic member 106d of the guide pin actuator 106 is not limited to a coil spring, and may be, for example, a leaf spring, a resin, a rubber spring, etc.

[0260] The upper electrode unit 102 may include a guide pin and an actuator for the guide pin. The guide pin may protrude downward and retract upward from the lower end (tip) 109a of the upper electrode 109.

[0261] The nut N may not have the protrusion N3.

[0262] The nut N is not limited to a quadrangular nut, and may be, for example, a polygonal nut other than a quadrangular nut or a circular nut.

[0263] The part N may be a nut, a washer or a sleeve with a through hole, or the like.

[0264] The part N may be, for example, a bolt without a through-hole. FIG. 20 shows a bolt transfer system 1 as a part transfer system according to another embodiment. In this case, in the bolt transfer system 1, a bolt holder 48 as a known holder is fixed to the tip of the rod 40 in the supply mechanism 4. The bolt holder 48 is provided with a stopper 65 that receives the bolt N. The supply mechanism 4 receives the bolt N as a part that has dropped from the chute 3 with the stopper 65 of the bolt holder 48 at the tip of the rod 40. The supply mechanism 4 supplies the bolt N as a part that has been received by the stopper 65 of the bolt holder 48 at the tip of the rod 40 to the destination position J by moving the rod 40 forward.

[0265] 21 shows a resistance welding machine 100 according to another embodiment. The upper actuator 110 is disposed above the upper holder 108. The upper actuator 110 is an electric actuator. The upper actuator 110 moves the upper holder 108 and the upper electrode 109 up and down by electrical action. The upper actuator 110 includes a cylinder 110a, a piston 110b, a drive rod 110c, a driven rod 110d, a vertical drive mechanism 110e, and a lid 110f.

[0266] The cylinder 110a is cylindrical and is disposed above the upper holder 108. The piston 110b is disposed within the cylinder 110a. The drive rod 110c is connected to the piston 110b and extends upward from the upper surface of the piston 110b. The upper end of the drive rod 110c is connected to a vertical drive mechanism 110e (for example, a drive motor or an electromagnetic solenoid) for reciprocating the drive rod 110c up and down.

[0267] The driven rod 110d is connected to the piston 110b and extends downward from the underside of the piston 110b. The lower end of the driven rod 110d is connected to the upper holder 108. The lower opening of the cylinder 110a is closed by a lid 110f. The cylinder 110a, the lid 110f, and the piston 110b define an air chamber 110g.

[0268] A hole 110i is provided in a side wall 110h of the cylinder 110a. The hole 110i faces the air chamber 110g and communicates between the inside and outside of the air chamber 110g. One end of a hose 110j is connected to the hole 110i in the side wall 110h of the cylinder 110a.

[0269] A cover 110k is provided between the lower end of the lower holder 103 and the upper end of the cylinder 106a of the guide pin actuator 106, covering both of them. A hole 110l is provided in the cover 110k. The hole 110l connects the inside and outside of the cover 110k. The other end of the hose 110j is connected to the hole 110l in the cover 110k. The internal space of the cover 110k communicates with the gaps between the inner surface 103a of the lower holder 103 and the inner surface 104c of the lower electrode 104 and the outer surface 105a of the guide pin 105.

[0270] In summary, the resistance welding machine 100 includes an upper actuator 110 serving as an actuator for the resistance welding machine. The upper actuator 110 moves (the upper holder 108 and) the upper electrode 109 downward, and at the same time, moves downward a piston 110b serving as a piston for the resistance welding machine disposed in a cylinder 110a serving as a cylinder for the resistance welding machine, thereby compressing an air chamber 110g serving as a gas chamber for the resistance welding machine.

[0271] The air chamber 110g communicates with the gaps between the inner surface 103a of the lower holder 103 and the inner surface 104c of the lower electrode 104 and the outer surface 105a of the guide pin 105 via the hose 110j. In other words, the air chamber 110g communicates with the inner surface 103a side of the lower holder 103 and the inner surface 104c side of the lower electrode 104. The air chamber 110g communicates with the outer surface 105a side of the guide pin 105.

[0272] The air A compressed in the air chamber 110g as a gas escapes upward through gaps between the inner surface 103a of the lower holder 103 and the inner surface 104c of the lower electrode 104 and the outer surface 105a of the guide pin 105. The air A compressed in the air chamber 110g as a gas escapes upward along the inner surface 103a of the lower holder 103 and the inner surface 104c of the lower electrode 104. The air A compressed in the air chamber 110g as a gas escapes upward along the outer surface 105a of the guide pin 105.

[0273] Dust (welding dust, etc.) generated in the resistance welding process by the resistance welding machine 100 can be removed by blowing air A (air blow) without using an air supply source.

[0274] The part N may also be, for example, a crimp bolt, a crimp nut, a pierce bolt, or a pierce nut.

[0275] As the gas, instead of air A, for example, nitrogen gas or the like may be used.

[0276] The application field of the part transfer system 1 is not limited to the resistance welding machine 100. The destination position J may be anything. For example, a crimping mechanism or a piercing mechanism may be disposed at the destination position J. [Industrial Applicability]

[0277] The present disclosure is applicable to part transfer systems and part welding systems, and is therefore extremely useful and has high industrial applicability. [Explanation of symbols]

[0278] Z vertical direction Z1 upper Z2 downward X Anteroposterior direction X1 forward X2 rear Y left / right direction O center axis C spiral H gap L gap G1 top position G2 lower position J Target position R Air chamber (gas chamber) E. Exterior space A. Air (gas) F restoring force (biasing force) P Pressure force N Nut (parts, bolts) N1 main body N1a surface N1b back side N1c side N2 screw hole (through hole) N3 protrusion t thickness T Thickness s Width across flats e Diagonal dimension double work Wa hole V Elastic force (biasing force) S Nut Welding System 1 Nut transfer system (parts transfer system, bolt transfer system) 2. Lifting mechanism 3 Shooter 4 Supply mechanism 5 Connecting pipe 5a Groove 5b Lid 10 outer cylinder 11 Exterior 12 Inner 13 Magnet (adsorption part) 13a small magnet 13b Small magnet 13c midpoint 13A First magnet 13B Second magnet 13C Third magnet 13D 4th magnet 14 Shaft (rotation drive part) 14a Exterior 15 Motor (rotation drive unit) 15a Arrow 16 Regulatory Guide (Regulatory Department) 17 First guide section 18 Second guide section 18a Fixed part 19 Posture change guide (posture change part) 19a First chamfer 19b Second chamfer 20 Stopper guide 20a Alignment guide (through hole) 21 Front and back sorting guide (front and back sorting section) 21a Mounting part 21b Projection 22 Anti-extension guide 23 Upper guide 23a Groove bottom wall 23b Groove side wall 24 Direction change guide (direction change section) 24a side wall 24b Upper wall 24c lower wall 24d entrance 25 Receptacle (reservoir) 26 Foundation 31 Cylindrical member 31a First inner surface 31b Second inner surface 31c inner groove 32 Long plate member 32a back side 32b surface 40 rods 40a Inside 41 Front end 42 Posterior part 43 Step surface 44 Air outlet (gas outlet) 45 Air inlet (gas inlet) 46 Air passage (gas passage) 47 Outer circumference 48 Bolt holder 50 pistons 51 cylinders 52 Lid 52a Main body 52b fitting part 52c hole 53 Actuator 53a Electric mechanism 53b Drive rod 60 Nut holder (parts holder) 61 Holder 61a Main body 61b fitting part 62 Receiving part 62a back wall 62b side wall 63 Door 64 Rod through hole 65 Stopper 66 Nut receiving chamber (parts receiving chamber) 67 Discharge hole 70 Check valve 80 Sealing mechanism 81 Bush 82 Coil spring (biasing member) 90 Connecting member 100 Resistance Welding Machine 101 Lower electrode unit 102 Upper electrode unit 103 Lower holder 103a Inside 104 Lower electrode (electrode) 104a Upper end (tip) 104b through hole 104c Inside 105 Guide pin 105a Exterior 106 Guide pin actuator 106a Cylinder 106b piston 106c Drive rod 106d Coil spring (elastic member) 107 Intervening Rod 108 Upper holder 109 Upper electrode (electrode) 109a Lower end (tip) 110 Upper actuator (resistance welding machine actuator, electric, blow mechanism actuator) 110a Cylinders (cylinders for resistance welding machines, cylinders for blow mechanisms) 110b Pistons (resistance welding machine pistons, blow mechanism pistons) 110c drive rod 110d driven rod 110e Up / Down Drive Mechanism 110f lid 110g air chamber (gas chamber for resistance welding machine, gas chamber for blow mechanism) 110h side wall 110i hole 110j hose 110k cover 110l hole

Claims

1. a parts transfer system; a resistance welding machine; The part transfer system includes: a lifting mechanism for lifting the part from a lower position to an upper position; a chute that drops the parts sent from the upper position of the lifting mechanism; a supply mechanism that receives the part dropped from the chute with a stopper and supplies the part received by the stopper to a target position by advancing a rod; the chute extends downward from the upper position of the lifting mechanism to the feeding mechanism without returning upward; the resistance welding machine includes a lower electrode and an upper electrode; the target position is between the lower electrode and the upper electrode; A guide pin protrudes and retracts from the tip of the lower electrode, the guide pin protrudes from the tip by an elastic force of an elastic member, and retracts from the tip by being pressed against the elastic force of the elastic member; the resistance welding machine includes a resistance welding machine actuator that moves the upper electrode up and down; the resistance welding machine actuator is an electric actuator, the resistance welding actuator includes a resistance welding cylinder and a resistance welding piston disposed in the resistance welding cylinder; the resistance welding cylinder and the resistance welding piston define a resistance welding gas chamber, the gas chamber for the resistance welding machine is disposed below the piston for the resistance welding machine, the gas chamber for the resistance welding machine communicates with the outer surface side of the guide pin via a hose; the resistance welding machine actuator moves the upper electrode downward and simultaneously moves the resistance welding machine piston downward, thereby compressing the gas in the resistance welding machine gas chamber; A parts welding system, wherein the gas compressed in the gas chamber for the resistance welding machine escapes upward along the outer surface of the guide pin.

2. The lifting mechanism includes: An outer cylinder extending vertically; a plurality of suction sections arranged in a spiral shape having a central axis extending vertically on the inner surface of the outer cylinder, the suction sections applying a magnetic field to the outer surface of the outer cylinder to suction the parts to the outer surface of the outer cylinder; a rotation drive unit that rotates the plurality of suction units around the central axis; The part welding system according to claim 1 , further comprising: a restricting unit that restricts rotational movement of the part to move the part upward along the outer surface of the outer cylinder.

3. The lifting mechanism has a front and back sorting unit, The part welding system according to claim 2, wherein the front / back sorting unit allows the part to pass when the front surface faces the outer surface, and rejects the part to prevent passage when the back surface faces the outer surface, based on a difference in protruding thickness from the outer surface of the outer cylinder.

4. The parts welding system according to claim 2 , wherein the lifting mechanism has a reservoir portion for accumulating the parts at the lower position.

5. The part welding system according to claim 2 , wherein the lifting mechanism includes a direction changer that changes the direction of the part moving upward along the outer surface of the outer cylinder downward at the upper position.

6. The shooter is a cylindrical member through which the part passes; a long plate member disposed inside the cylindrical member and extending along the cylindrical member, The part welding system according to claim 1 or 2, wherein the part slides on the long plate member.

7. The cylindrical member is made of a flexible material, 7. The parts welding system according to claim 6, wherein the elongated plate member is made of a material that is harder than a material that constitutes the tubular member and that is elastically deformable.

8. The part has a protrusion provided on a rear surface, The part welding system of claim 6 , wherein the protrusion of the part slides on the elongated plate member.

9. the supply mechanism has an actuator that moves the rod back and forth, The part welding system according to claim 1 or 2, wherein the actuator is an electric actuator.

10. The supply mechanism includes: the rod that advances to supply the part having a through-hole to the target position; a piston coupled to the rod; a cylinder that accommodates the rod and the piston; a lid that closes the cylinder forward of the piston and through which the rod extending forward from the piston passes; an actuator that moves the piston and the rod back and forth, the piston, the cylinder, and the lid define a gas chamber; The rod is a gas outlet provided on an outer periphery of a front end portion of the rod inserted into the through hole of the part, the gas outlet blowing out; a gas inlet port provided rearward of the gas outlet and through which the gas is introduced from the gas chamber; The part welding system according to claim 1 or 2, further comprising: a gas passage extending longitudinally inside the rod and through which the gas passes from the gas inlet to the gas outlet.

11. A lower electrode; an upper electrode; an actuator for a resistance welding machine that moves the upper electrode up and down; A guide pin protrudes and retracts from the tip of the lower electrode, the guide pin protrudes from the tip by an elastic force of an elastic member, and retracts from the tip by being pressed against the elastic force of the elastic member; the resistance welding machine actuator is an electric actuator, the resistance welding actuator includes a resistance welding cylinder and a resistance welding piston disposed in the resistance welding cylinder; the resistance welding cylinder and the resistance welding piston define a resistance welding gas chamber, the gas chamber for the resistance welding machine is disposed below the piston for the resistance welding machine, the gas chamber for the resistance welding machine communicates with the outer surface side of the guide pin via a hose; the resistance welding machine actuator moves the upper electrode downward and simultaneously moves the resistance welding machine piston downward, thereby compressing the gas in the resistance welding machine gas chamber; The gas compressed in the gas chamber for the resistance welding machine escapes upward along the outer surface of the guide pin.

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