Electrode replenishment device for spot welding

Abstract

This electrode replenishment device (1) for spot welding comprises a device body (2) that moves any one electrode (T) positioned in a branch passage part (3a). An electrode setting part (5) sets the electrode (T) in the branch passage part (3a). One end of a first guide cylindrical body (6) is connected to a first electrode storage device, and the other end of the first guide cylindrical body (6) is connected to an opening at one end of the branch passage part (3a). One end of a second guide cylindrical body (7) is connected to a second electrode storage device, and the other end of the second guide cylindrical body (7) is connected to an opening at the other end of the branch passage part (3a). A first air introduction unit (8) introduces compressed air into the first guide cylindrical body (6). A second air introduction unit (9) introduces compressed air into the second guide cylindrical body (7).

Description

Spot Welding Electrode Replenishment Device

[0001] The present invention relates to a spot welding electrode replenishment device that automatically replenishes electrodes to an electrode storage device that stores replacement electrodes to be attached to a spot welding gun.

[0002] Conventionally, in a spot welding gun, a pair of electrodes that sandwich and pressurize and energize a welding object during welding are attached to the shank portion of the gun body by fitting, and the two electrodes face each other. Each of these electrodes needs to be periodically replaced to stabilize the welding quality. Each replacement electrode is stored, for example, in an electrode storage device disposed around a welding robot as disclosed in Patent Document 1. This electrode storage device includes a storage case that can accommodate a plurality of fitting recesses that open in the same direction and fit into the shank portion of the spot welding gun. This storage case is detachable from the main body portion of the device. In order to efficiently replace a pair of electrodes attached to face each other, two electrode storage devices may be disposed around the welding robot. At this time, each electrode storage device is arranged in a posture such that the opening direction of the fitting recess of each electrode stored in one electrode storage device is opposite to the opening direction of the fitting recess of each electrode stored in the other electrode storage device.

[0003] Japanese Patent No. 6236192

[0004] By the way, when each electrode storage device as described above has no electrodes or the number of electrodes in the storage case of the device decreases, it is necessary to exchange the storage case with a spare storage case in which a plurality of electrodes are stored in advance. However, the operation of exchanging the storage case of each electrode storage device requires the operator to stop the operation of the production line and enter the inside to perform the operation, which has the problem of deteriorating production efficiency. Also, in terms of safety management, there is a demand to reduce the operation performed by the operator entering the production line as much as possible. To address this, for example, it is conceivable to use a parts feeder that can sequentially supply a large number of electrodes from the outside to the inside of the production line while aligning them, and automatically replenish the electrodes into the storage case of each electrode storage device in sequence.

[0005] However, since parts feeders generally supply each electrode sequentially in the same orientation, if one attempts to replenish electrodes from the same direction into two electrode storage devices whose fitting recess openings face opposite directions, it becomes necessary to change the orientation of the replenished electrodes to correspond to each electrode storage device. To avoid this, a parts feeder would be required for each electrode storage device, resulting in increased costs. The present invention has been made in view of these points, and its objective is to provide a low-cost spot welding electrode replenishment device that can increase production efficiency and reduce the amount of work performed by operators on the production line.

[0006] To achieve the above objective, the present invention is characterized by using two guide cylinders capable of guiding electrodes, in which an electrode located inside one guide cylinder is pushed from the tip side of the electrode with compressed air and sent to one electrode storage device, while an electrode located inside the other guide cylinder is pushed from the base side of the electrode with compressed air and sent to the other electrode storage device. Specifically, the present invention targets a spot welding electrode replenishment device that replenishes electrodes from the same direction to first and second electrode storage devices, which store a pair of electrodes to be attached to a spot welding gun in opposite orientations, and the following measures have been taken.

[0007] In other words, the spot welding electrode replenishment device according to the first invention is characterized by comprising: a device body having a branch passage section with openings at both ends inside, which moves the electrode located in the branch passage section to either one side while its central axis is aligned with the branch passage section; an electrode setting section capable of setting the electrode in the branch passage section while its central axis is aligned with the branch passage section; a first guide cylinder, one end of which is connected to the first electrode storage device and the other end of which is configured to be connectable to one end opening of the branch passage section, and capable of guiding the electrode; a second guide cylinder, one end of which is connected to the second electrode storage device and the other end of which is configured to be connectable to the other end opening of the branch passage section, and capable of guiding the electrode; a first air introduction section, which can introduce compressed air toward the first electrode storage device into the first guide cylinder; and a second air introduction section, which can introduce compressed air toward the second electrode storage device into the second guide cylinder. In this configuration, the spot welding electrode replenishment device operates so that electrodes can be replenished in both the first and second electrode storage devices, which have electrodes facing different orientations, using only one electrode set unit. Furthermore, it operates so that electrodes can be replenished in both the first and second electrode storage devices from the same direction, even when the operator is outside the production line.

[0008] The spot welding electrode replenishment device according to the second invention is characterized in that, in the first invention, the device body comprises a main body frame having a branch passage portion extending linearly vertically, and a connection switching mechanism for switching the connection between the other end opening of the second guide cylinder and the air inlet of the first air introduction portion to the other end opening of the branch passage portion, wherein the other end opening of the first guide cylinder is connected to one end opening of the branch passage portion, and the second air introduction portion is connected to a position closer to the other end of the second guide cylinder. In the spot welding electrode replenishment device configured in this way, when the air inlet of the first air introduction portion is connected to the other end opening of the branch passage portion by the connection switching mechanism, and compressed air is introduced from the first air introduction portion, the electrode set in the branch passage portion acts to move to the first guide cylinder. Furthermore, when the other end opening of the second guide cylinder is connected to the other end opening of the branch passage portion by the connection switching mechanism, and an electrode is set in the branch passage portion, the electrode acts to fall from the branch passage portion and move to the second guide cylinder. The spot welding electrode replenishment device according to the third invention is characterized in that, in the second invention, the connection switching mechanism comprises a slide plate fixed in a position where the other end opening of the second guide cylinder and the air inlet of the first air introduction section face upward, and a first actuator that slides the slide plate horizontally, wherein the sliding operation of the slide plate toward one side connects the other end opening of the second guide cylinder to the other end opening of the branch passage section, while the sliding operation of the slide plate toward the other side connects the air inlet of the first air introduction section to the other end opening of the branch passage section. In the spot welding electrode replenishment device configured in this way, the switching operation between the other end opening of the second guide cylinder and the air inlet of the first air introduction section with respect to the other end opening of the branch passage section is performed solely by the sliding operation of the slide plate.

[0009] The spot welding electrode replenishment device according to the fourth invention is characterized in that, in any one of the first to third inventions, the electrode set section sets the electrode in the branch passage section such that the tip side faces the first guide cylinder, and the flow rate of compressed air introduced in the second air introduction section is set to be higher than that of the first air introduction section. In a spot welding electrode replenishment device configured in this way, the energy applied from the compressed air to the electrode located in the first guide cylinder is reduced, while the energy applied from the compressed air to the electrode located in the second guide cylinder is increased. The spot welding electrode replenishment device according to the fifth invention is characterized in that, in any one of the first to third inventions, the electrode set section sets the electrode in the branch passage section such that the tip side faces the first guide cylinder, the compressed air introduced from the first air introduction section and the compressed air introduced from the second air introduction section are set to be the same flow rate, and at least the portion of the second guide cylinder including the inner circumferential surface is made of a material with lower frictional resistance than at least the portion of the first guide cylinder including the inner circumferential surface. In a spot welding electrode replenishment device configured in this way, the electrode located in the second guide cylinder acts to move more easily than the electrode located in the first guide cylinder.

[0010] The spot welding electrode replenishment device according to the sixth invention is characterized in that, in the fifth invention, the middle portion of the first guide cylinder is made of urethane material, and the middle portion of the second guide cylinder is made of Teflon® material. The spot welding electrode replenishment device configured in this way is designed to be made of relatively easy-to-process and readily available materials. The spot welding electrode replenishment device according to the seventh invention is characterized in that, in the second or third invention, the main body frame comprises a first passage portion extending in a horizontal direction perpendicular to the branch passage portion and one end of which communicates with the branch passage portion, and a second passage portion extending in a horizontal direction perpendicular to the first passage portion and one end of which communicates with the other end of the first passage portion, and the electrode set portion comprises a parts feeder that sequentially supplies the electrodes to the second passage portion, and a second actuator that presses the electrode located in the portion of the second passage portion that communicates with the first passage portion toward one end of the first passage portion in a direction along the first passage portion. In a spot welding electrode replenishment device configured in this way, each replenishment electrode, which is aligned by a parts feeder and sequentially sent to the main body of the device, is accurately fed one by one in the same orientation to the branching passage section via the first and second passage sections.

[0011] In the spot welding electrode replenishment device of the first invention, when the electrode set in the branching passage is moved to the opening side at one end by the device body and compressed air is introduced into the first guide cylinder by the first air introduction unit, the electrode is guided into the first guide cylinder with its tip facing the direction of travel and replenished into the first electrode storage device. On the other hand, when the electrode set in the branching passage is moved to the opening side at the other end by the device body and compressed air is introduced into the second guide cylinder by the second air introduction unit, the electrode is guided into the second guide cylinder with its base facing the direction of travel and replenished into the second electrode storage device. In this way, electrodes can be replenished into the first and second electrode storage devices, which have different orientations of stored electrodes, using only one electrode setting unit, resulting in a low-cost spot welding electrode replenishment device. Furthermore, even if the operator is outside the production line, electrodes can be replenished into the first and second electrode storage devices from the same direction. Therefore, even if the electrodes of the first and second electrode storage devices are lost or reduced in number, it becomes unnecessary for workers to enter the production line to replace the housing cases of the first and second electrode storage devices. This increases the production efficiency of the production line and reduces the amount of work required of workers within the production line.

[0012] In the spot welding electrode replenishment device of the second invention, the connection switching mechanism connects the air inlet of the first air introduction unit to the other end opening of the branch passage unit, and when compressed air is introduced from the first air introduction unit, the electrode set in the branch passage unit moves to the first guide cylinder. Subsequently, as the introduction of compressed air by the first air introduction unit continues, the electrode is pushed by the compressed air and guided to the first guide cylinder, moving toward the first electrode storage device. On the other hand, the connection switching mechanism connects the other end opening of the second guide cylinder unit to the other end opening of the branch passage unit, and when an electrode is set in the branch passage unit, the electrode falls from the branch passage unit and moves toward the second guide cylinder. Subsequently, when compressed air is introduced into the second guide cylinder, the electrode is pushed by the compressed air and guided to the second guide cylinder, moving toward the second electrode storage device. In this way, by utilizing the first air introduction section used for moving the electrode located in the first guide cylinder, the electrode set in the branching passage section of the device body can be moved toward the first guide cylinder side and toward the second guide cylinder side, respectively. Therefore, there is no need to provide separate air introduction sections for moving the electrode toward the first guide cylinder side and toward the second guide cylinder side in the branching passage section, resulting in a low-cost structure.

[0013] In the third invention, the electrode replenishment device for spot welding allows switching between the other end opening of the second guide cylinder and the air inlet of the first air introduction section, relative to the other end opening of the branch passage section, to be performed solely by a sliding motion of a slide plate. Therefore, the connection switching mechanism has a simple structure, resulting in a low-cost and less prone-to-failure device. In the fourth invention, the electrode replenishment device for spot welding allows for a decrease in the energy supplied by compressed air to the electrode located in the first guide cylinder, while increasing the energy supplied by compressed air to the electrode located in the second guide cylinder. Therefore, the movement speed of the electrode moving through the first guide cylinder, where compressed air is received at the fitting recess on the base end of the electrode, resulting in less energy loss from the compressed air to the electrode, and the movement speed of the electrode moving through the second guide cylinder, where compressed air is received at the hemispherical portion on the tip end of the electrode, resulting in greater energy loss from the compressed air to the electrode, become the same or approach each other. This suppresses variations in the movement of each electrode on the first electrode storage device side and the second electrode storage device side, preventing uneven progression of device deterioration caused by the movement of each electrode.

[0014] In the spot welding electrode replenishment device of the fifth invention, the electrode located in the second guide cylinder moves more easily than the electrode located in the first guide cylinder. Therefore, the movement speed of the electrode moving through the first guide cylinder, where compressed air is received at the fitting recess on the base end of the electrode, resulting in less energy loss from the compressed air to the electrode, and the movement speed of the electrode moving through the second guide cylinder, where compressed air is received at the hemispherical portion on the tip end of the electrode, resulting in greater energy loss from the compressed air to the electrode, become the same or approach each other. This suppresses variations in the movement of each electrode on the first electrode storage device side and the second electrode storage device side, preventing uneven deterioration of the device caused by the movement of each electrode.

[0015] The sixth invention, a spot welding electrode replenishment device, can be made from relatively easy-to-process and readily available materials, resulting in an inexpensive device. The seventh invention, a spot welding electrode replenishment device, allows each replenishment electrode, which is aligned by a parts feeder and sequentially sent to the device body, to be accurately fed one by one in the same orientation to the branching passage section via the first and second passage sections. Therefore, the replenishment of each electrode to the first and second electrode storage devices can be performed efficiently.

[0016] This is a perspective view showing a spot welding electrode replenishment device according to an embodiment of the present invention and a pair of electrode storage devices from which electrodes are replenished by the spot welding electrode replenishment device. This is a cross-sectional view taken along line II-II in Figure 1. This is a cross-sectional view taken along line III-III in Figure 2. This is a view taken after Figure 2, immediately after the start of electrode replenishment to one of the electrode storage devices. This is a cross-sectional view taken along line V-V in Figure 4. This is a view corresponding to Figure 2, showing the state immediately before the start of electrode replenishment to the other electrode storage device. This is a cross-sectional view taken along line VII-VII in Figure 6. This is a view taken after Figure 6, immediately after the start of electrode replenishment to the other electrode storage device. This is a cross-sectional view taken along line IX-IX in Figure 1. This is a view taken after Figure 9, immediately after the electrodes replenished in one of the electrode storage devices have been transferred to the electrode removal position. This is a cross-sectional view taken along line XI-XI in Figure 1. This is a cross-sectional view taken along line XII-XII in Figure 11.

[0017] The embodiments of the present invention will be described in detail below with reference to the drawings. Note that the following description of preferred embodiments is essentially illustrative.

[0018] Figure 1 shows a spot welding electrode replenishment device 1 according to an embodiment of the present invention, and a first electrode storage device 10A and a second electrode storage device 10B for storing replacement electrodes T for a spot welding gun G. The spot welding electrode replenishment device 1 automatically replenishes unused electrodes T to the first and second electrode storage devices 10A and 10B, and is located outside the automobile production line. As shown in Figure 2, the spot welding electrode replenishment device 1 comprises a device body 2 that is substantially L-shaped in side view, and the device body 2 comprises a main frame 3 that is substantially rectangular block-shaped and extends horizontally, and a connection switching mechanism 4 located below the main frame 3.

[0019] A branched passage section 3a is formed inside one longitudinal side of the main frame 3, extending linearly vertically with a circular cross-section and open at both ends. This branched passage section 3a allows the electrode T to be moved either upward or downward while its central axis is aligned with the branched passage section 3a (see Figures 4 and 8). Furthermore, as shown in Figures 2 and 3, the main frame 3 includes a first passage section 3b extending linearly horizontally perpendicular to the branched passage section 3a, with one end communicating with the branched passage section 3a, and a second passage section 3c extending horizontally perpendicular to the first passage section 3b, with one end communicating with the other end of the first passage section 3b. The region from the middle of the first passage section 3b to the other end and the second passage section 3c have a roughly U-shaped cross-section with an open top.

[0020] The connection switching mechanism 4 includes a pair of support frames 41 that extend in the longitudinal direction of the main frame 3 and are fixed to the lower surface of the main frame 3, spaced apart in the width direction of the main frame 3. A slide plate 42, which has a rectangular shape in plan view, is disposed between the two support frames 41, and a first air cylinder 43 (first actuator) is fixed to one end of each support frame 41. A first through hole 42a with a circular cross-section that penetrates vertically is formed in the center of one longitudinal side of the slide plate 42, and the cross-section of the first through hole 42a is the same size as the cross-section of the branch passage section 3a. A second through hole 42b with a circular cross-section that penetrates vertically is formed in the center of the other longitudinal side of the slide plate 42, and the cross-section of the second through hole 42b is smaller than the cross-section of the branch passage section 3a.

[0021] The first air cylinder 43 is extendable and retractable along the longitudinal direction of the main frame 3 and includes a first piston rod 43a whose tip is connected to one end of the slide plate 42 in the longitudinal direction. When the first piston rod 43a is retracted, as shown in Figures 2 and 3, the slide plate 42 slides to one side in the horizontal direction so that the second through hole 42b corresponds to the lower end opening (other end opening) of the branch passage 3a. Conversely, when the first piston rod 43a is extended, as shown in Figures 6 and 7, the slide plate 42 slides to the other side in the horizontal direction so that the first through hole 42a corresponds to the lower end opening of the branch passage 3a.

[0022] As shown in Figures 1 to 3, an electrode setting section 5 is provided on the side of the main body 2 of the device, on which electrodes T can be set in the branch passage section 3a. This electrode setting section 5 includes a parts feeder 51 provided on one side in the width direction of the main frame 3, a second air cylinder 52 (second actuator) fixed to the other end in the longitudinal direction of the main frame 3, a third air cylinder 53 fixed to the other side in the width direction of the main frame 3, and an electrode detection sensor 54 arranged in parallel with the third air cylinder 53. The parts feeder 51 includes an upwardly opening bowl section 51a capable of storing a large number of electrodes T, and a substantially straight electrode guide section 51b with a concave cross-section that connects the outer circumference of the bowl section 51a and the other end of the second passage section 3c. The bowl section 51a is configured to be rotatable about a rotation axis that extends vertically. The parts feeder 51 is designed so that, by the rotation of the bowl portion 51a, each electrode T located in the bowl portion 51a is guided by the electrode guide portion 51b, aligning in a straight line with its tip facing upward, and is then sequentially supplied to the second passage portion 3c.

[0023] The second air cylinder 52 is equipped with a second piston rod 52a that is extendable and retractable within the first passage 3b along the longitudinal direction of the main frame 3. A pressing block 52b, which has a shape corresponding to the first passage 3b, is fixed to the tip of the second piston rod 52a. When the second piston rod 52a is extended, as shown in Figures 4 and 5, the pressing block 52b presses the electrode T located in the portion of the second passage 3c that communicates with the first passage 3b toward one side of the first passage 3b in a direction along the first passage 3b. The electrode T pressed by the pressing block 52b is then set in the branch passage 3a with its centerline aligned with the branch passage 3a and its tip facing the upper end opening side (one end opening side) of the branch passage 3a.

[0024] The third air cylinder 53 is equipped with a third piston rod 53a that is extendable and retractable along the width direction of the main frame 3 so as to obstruct the first passage portion 3b, and this third piston rod 53a is positioned along the inner wall of the electrode guide portion 51b on the side of the branch passage portion 3a. The third air cylinder 53 is configured such that when the third piston rod 53a is extended, as shown in Figures 2 and 3, the third piston rod 53a obstructs the first passage portion 3b, preventing the electrode T from passing through the first passage portion 3b, and when the third piston rod 53a is retracted, as shown in Figures 4 and 5, the third piston rod 53a is no longer positioned in the first passage portion 3b, allowing the electrode T to pass through the first passage portion 3b. The electrode detection sensor 54 is capable of detecting whether or not the electrode T is located in the portion of the second passage portion 3c that communicates with the first passage portion 3b.

[0025] As shown in Figure 1, a first guide cylinder 6 is disposed between the main body of the device 2 and the first electrode storage device 10A, with one end opening connected to the first electrode storage device 10A and the other end opening connected to one end opening of the branch passage 3a. The first guide cylinder 6 is capable of guiding the electrode T so that its central axis is aligned with the center line of the cylinder. As shown in Figure 2, the first guide cylinder 6 comprises a first connecting cylinder portion 6a fixed to the periphery of the upper end opening of the branch passage 3a, and a first flexible cylinder portion 6b made of urethane material fitted onto the first connecting cylinder portion 6a. In other words, the middle part of the first guide cylinder 6 is made of urethane material.

[0026] On the other hand, as shown in Figure 1, a second guide cylinder 7 is provided between the main body of the device 2 and the second electrode storage device 10B. One end of the second guide cylinder 7 is connected to the second electrode storage device 10B, and the other end opening is fixed in an upward position to the first through hole 42a of the slide plate 42. The second guide cylinder 7 is capable of guiding the electrode T so that its central axis is aligned with the center line of the cylinder. As shown in Figure 2, the second guide cylinder 7 comprises a second connecting cylinder portion 7a fixed to the periphery of the lower end opening of the first through hole 42a in the slide plate 42, and a second flexible cylinder portion 7b made of Teflon® material fitted onto the second connecting cylinder portion 7a. In other words, the middle section of the second guide cylinder 7 is made of Teflon® material, which has lower frictional resistance than the middle section of the first guide cylinder 6, which is made of urethane material.

[0027] Below the slide plate 42, a first air introduction section 8 is provided, which allows compressed air to be introduced into the first guide cylinder 6. The first air introduction section 8 is arranged in parallel with the other end portion of the second guide cylinder 7, and the air inlet 8a of the first air introduction section 8 is fixed in an upward position to the second through hole 42b in the slide plate 42. As shown in Figures 6 and 7, the connection switching mechanism 4 is configured to connect the other end opening of the second guide cylinder 7 to the lower end opening of the branch passage section 3a via the first through hole 42a when the slide plate 42 slides to one side. In this state, as shown in Figure 8, when the third piston rod 53a of the third air cylinder 53 is retracted and the second piston rod 52a of the second air cylinder 52 is extended to set the electrode T in the branch passage section 3a, the electrode T falls and moves to the second guide cylinder 7. In other words, the main body of the device 2 moves the electrode T located in the branching passage 3a downward so that its central axis is aligned with the branching passage 3a and moves toward the second guide cylinder 7.

[0028] On the other hand, as shown in Figures 2 and 3, the connection switching mechanism 4 connects the air inlet 8a of the first air introduction section 8 to the lower end opening of the branch passage section 3a via the second through hole 42b by sliding the slide plate 42 to the other side. This allows the first air introduction section 8 to introduce compressed air toward the first electrode storage device 10A into the first guide cylinder 6 via the second through hole 42b and the branch passage section 3a. In this state, as shown in Figures 4 and 5, the third piston rod 53a of the third air cylinder 53 is retracted and the second piston rod 52a of the second air cylinder 52 is extended to set the electrode T in the branch passage section 3a, and when compressed air is introduced into the branch passage section 3a via the second through hole 42b by the first air introduction section 8, the electrode T rises and moves toward the first guide cylinder 6. In other words, the main body of the device 2 moves the electrode T located in the branching passage 3a upward so that its central axis is aligned with the branching passage 3a and it faces the first guide cylinder 6. In this way, the connection switching mechanism 4 can switch the connection between the lower end opening of the branching passage 3a and the other end opening of the second guide cylinder 7 and the air inlet 8a of the first air introduction section 8.

[0029] Furthermore, as shown in Figure 7, a second air introduction section 9 is connected to the second connecting cylinder portion 7a of the second guide cylinder 7, which allows compressed air to be introduced into the second guide cylinder 7. Specifically, the second air introduction section 9 is connected to a position near the other end of the second guide cylinder 7 and comprises a connecting block 91 having a communication hole portion 91a that extends linearly diagonally downward and communicates with the inside of the second connecting cylinder portion 7a, and an air introduction tube 92 connected to the communication hole portion 91a. The second air introduction section 9 is capable of introducing compressed air toward the second electrode storage device 10B into the second guide cylinder 7, and the compressed air introduced from the first air introduction section 8 to the first guide cylinder 6 and the compressed air introduced from the second air introduction section 9 to the second guide cylinder 7 are set to the same flow rate.

[0030] As shown in Figure 1, the first electrode storage device 10A includes a roughly rectangular cylindrical storage case 11 extending horizontally, and this storage case 11 is detachably attached to one side of an electrode removal device X1 that allows the electrode T to be removed from the spot welding gun G. Inside the storage case 11, as shown in Figure 9, a linear storage passage 11a is formed along the longitudinal direction of the storage case 11, and the electrode T can be stored in the storage passage 11a with its central axis extending vertically and its tip facing downward. That is, the storage passage 11a of the first electrode storage device 10A can accommodate the electrode T such that a fitting recess T1 for fitting the electrode T into the shank G1 of the spot welding gun G opens upward. An electrode outlet 11b from which the electrode T can be removed is formed on the upper surface of one end of the housing passage 11a, and a ball plunger 11c for pressing the electrode T against the other side of the housing passage 11a is attached to one side of the housing passage 11a near one end. Meanwhile, one end of the first guide cylinder 6 is connected from above to the upper surface of the other end of the housing passage 11a, and a pressing mechanism 12 is provided at the other end of the housing passage 11a.

[0031] The pressing mechanism 12 includes a substantially cylindrical pressing air cylinder 13 whose centerline extends in the direction of extension of the housing passage 11a, with one end fixed to the other end of the housing case 11. A guide hole 13b is formed at the center of one end of the pressing air cylinder 13, which connects the hollow portion 13a formed inside the pressing air cylinder 13 to the housing passage 11a. Furthermore, a first air inlet hole 13c and a second air inlet hole 13d are formed near one end and the other end of the pressing air cylinder 13, respectively, allowing compressed air to be introduced into the hollow portion 13a, and these are connected to an air compressor via piping (not shown).

[0032] A disc-shaped piston 14 is disposed in the hollow section 13a, dividing the hollow section 13a into two parts, and the piston 14 is slidable along the centerline of the cylinder of the pressing air cylinder 13. A rod member 15 extending along the centerline of the cylinder of the pressing air cylinder 13 is integrally provided at the center of the piston 14 on the side of the housing passage 11a, and the rod member 15 is slidably fitted into the guide hole 13b. A block-shaped pressing member 16 housed in the housing passage 11a is connected to the tip of the rod member 15, and the pressing member 16 is movable back and forth along the housing passage 11a.

[0033] When compressed air is introduced into the hollow section 13a via the second air inlet hole 13d of the pressing mechanism 12, as shown in Figure 10, the piston 14 slides toward the housing passage 11a, causing the rod member 15 to slide toward the housing passage 11a while being guided by the guide hole 13b, and the pressing member 16 presses the electrode T, which has been replenished in the housing passage 11a via the first guide cylinder 6, to a position corresponding to the electrode outlet 11b. On the other hand, when compressed air is introduced into the hollow section 13a via the first air inlet hole 13c of the pressing mechanism 12, as shown in Figure 9, the piston 14 slides toward the side away from the housing passage 11a, causing the rod member 15 to slide toward the side away from the housing passage 11a while being guided by the guide hole 13b, and the pressing member 16 returns to its original position.

[0034] As shown in Figures 11 and 12, the second electrode storage device 10B has the same structure as the first electrode storage device 10A, except that it is detachably attached to the other side of the electrode removal device X1, the storage case 11 has an inverted structure, and the electrode T is stored in the storage passage 11a with its tip facing upward. Therefore, the same reference numerals are used for the same parts as in the first electrode storage device 10A, and detailed explanations are omitted. In this way, the first electrode storage device 10A and the second electrode storage device 10B each store a pair of electrodes T to be attached to the spot welding gun G in opposite orientations, and the spot welding electrode replenishment device 1 replenishes electrodes T to the first electrode storage device 10A and the second electrode storage device 10B from the same direction (from above).

[0035] Next, the operation of replenishing electrodes T to the first electrode storage device 10A and the second electrode storage device 10B of the spot welding electrode replenishment device 1 will be described in detail. First, the operator operates the parts feeder 51, which already has a large amount of electrodes T stored in the bowl portion 51a, and rotates the bowl portion 51a. Then, as shown in Figures 2 and 3, each electrode T located in the bowl portion 51a is guided by the electrode guide portion 51b while aligning in a straight line with its tip facing upward, and is sequentially supplied to the second passage portion 3c in the device body 2, until the leading electrode T reaches the first passage portion 3b.

[0036] Next, as shown in Figure 1, the used electrode T attached to the upper shank G1 of the spot welding gun G is removed by the electrode removal device X1. Then, the upper shank G1 of the spot welding gun G is fitted into the fitting recess T1 of the unused electrode T located in the storage passage 11a of the first electrode storage device 10A via the electrode outlet 11b of the first electrode storage device 10A, thereby attaching the electrode T to the shank G1. After that, the electrode T is removed to the outside of the first electrode storage device 10A via the electrode outlet 11b. When the electrode T is removed to the outside of the first electrode storage device 10A, the third piston rod 53a of the third air cylinder 53 retracts, and then the second piston rod 52a of the second air cylinder 52 extends. As a result, as shown in Figures 4 and 5, the electrode T located in the first passage 3b is pressed by the pressing block 52b and reaches the branch passage 3a.

[0037] When the electrode T reaches the branching passage 3a, the first air introduction unit 8 is activated and compressed air is introduced into the branching passage 3a through the second through-hole 42b of the slide plate 42, pressing the electrode T upward. Then, as shown in Figure 9, the electrode T is guided by the first guide cylinder 6 and then reaches the storage passage 11a of the first electrode storage device 10A. In other words, the electrode T is replenished in the first electrode storage device 10A. When the electrode T reaches the storage passage 11a of the first electrode storage device 10A, the pressing mechanism 12 is activated and compressed air is introduced into the hollow section 13a through the second air introduction hole 13d of the pressing air cylinder 13, causing the piston 14 and rod member 15 to slide toward the storage passage 11a, and the pressing member 16 presses the electrode T to a position corresponding to the electrode outlet 11b. Then, the electrode T, having moved to a position corresponding to the electrode outlet 11b of the housing passage 11a, is pressed against the wall surface of the housing passage 11a by the ball plunger 11c and held in place, entering a state ready for installation.

[0038] Next, as shown in Figure 1, the used electrode T attached to the lower shank G1 of the spot welding gun G is removed by the electrode removal device X1. Then, the lower shank G1 of the spot welding gun G is fitted into the fitting recess T1 of the unused electrode T located in the storage passage 11a of the second electrode storage device 10B via the electrode outlet 11b of the second electrode storage device 10B, thereby attaching the electrode T to the shank G1. After that, the electrode T is removed to the outside of the second electrode storage device 10B via the electrode outlet 11b. Once the electrode T is removed to the outside of the second electrode storage device 10B, as shown in Figures 6 and 7, the first piston rod 43a of the first air cylinder 43 extends, the slide plate 42 slides, and the other end opening of the second guide cylinder 7 is connected to the other end opening of the branch passage 3a via the first through hole 42a. Subsequently, the third piston rod 53a of the third air cylinder 53 retracts, and then the second piston rod 52a of the second air cylinder 52 extends. As a result, as shown in Figure 8, the electrode T located in the first passage 3b is pressed by the pressing block 52b and reaches the branch passage 3a.

[0039] The electrode T, having reached the branching passage 3a, falls through the branching passage 3a, passes through the first through-hole 42a, enters the second guide cylinder 7, and passes through the connection block 91 of the second air introduction section 9. Then the second air introduction section 9 is activated and compressed air is introduced into the second guide cylinder 7, pressing the electrode T. The electrode T is then guided by the second guide cylinder 7 to the storage passage 11a of the second electrode storage device 10B. In other words, the electrode T is replenished in the second electrode storage device 10B. When the electrode T reaches the storage passage 11a of the second electrode storage device 10B, the pressing mechanism 12 is activated and compressed air is introduced into the hollow section 13a through the second air introduction hole 13d of the pressing air cylinder 13. As shown in Figures 11 and 12, the piston 14 and the rod member 15 slide towards the storage passage 11a, and the pressing member 16 presses the electrode T to a position corresponding to the electrode outlet 11b. Then, the electrode T, having moved to a position corresponding to the electrode outlet 11b of the housing passage 11a, is pressed against the wall surface of the housing passage 11a by the ball plunger 11c and held in place, entering a state ready for installation.

[0040] As described above, according to the embodiment of the present invention, when the electrode T set in the branching passage section 3a is moved to the upper end opening (one end opening) side by the device body 2 and compressed air is introduced into the first guide cylinder 6 by the first air introduction section 8, the electrode T is guided into the first guide cylinder 6 with its tip facing the direction of travel and is replenished in the first electrode storage device 10A. On the other hand, when the electrode T set in the branching passage section 3a is moved to the lower end opening (other end opening) side by the device body 2 and compressed air is introduced into the second guide cylinder 7 by the second air introduction section 9, the electrode T is guided into the second guide cylinder 7 with its base end facing the direction of travel and is replenished in the second electrode storage device 10B. In this way, the replenishment of electrodes T in the first electrode storage device 10A and the second electrode storage device 10B, which have different orientations of the stored electrodes T, can be performed with only one electrode setting section 5, resulting in a low-cost spot welding electrode replenishment device 1. Furthermore, even when an operator is outside the production line, electrodes T can be replenished in the first electrode storage device 10A and the second electrode storage device 10B from the same direction. Therefore, even if electrodes T run out in the first electrode storage device 10A and the second electrode storage device 10B, it becomes unnecessary for an operator to enter the production line to replace the storage cases 11 of the first electrode storage device 10A and the second electrode storage device 10B, thereby increasing the production efficiency of the production line and reducing the amount of work performed by operators within the production line.

[0041] Furthermore, when the connection switching mechanism 4 connects the air inlet 8a of the first air introduction unit 8 to the other end opening of the branch passage unit 3a, and compressed air is introduced from the first air introduction unit 8, the electrode T set in the branch passage unit 3a moves to the first guide cylinder 6. Subsequently, as the introduction of compressed air by the first air introduction unit 8 continues, the electrode T is pushed by the compressed air and guided to the first guide cylinder 6, moving toward the first electrode storage device 10A. On the other hand, when the connection switching mechanism 4 connects the other end opening of the second guide cylinder 7 to the other end opening of the branch passage unit 3a, and the electrode T is set in the branch passage unit 3a, the electrode T falls from the branch passage unit 3a and moves toward the second guide cylinder 7. Subsequently, when compressed air is introduced into the second guide cylinder 7, the electrode T is pushed by the compressed air and guided to the second guide cylinder 7, moving toward the second electrode storage device 10B. In this way, by utilizing the first air introduction section 8 used for moving the electrode T located in the first guide cylinder 6, the electrode T set in the branch passage section 3a of the device body 2 can be moved toward the first guide cylinder 6 and toward the second guide cylinder 7, respectively. Therefore, there is no need to provide separate air introduction sections for moving the electrode T toward the first guide cylinder 6 and toward the second guide cylinder 7 in the branch passage section 3a, resulting in a low-cost structure.

[0042] Furthermore, the switching operation between the other end opening of the second guide cylinder 7 and the air inlet 8a of the first air introduction section 8, relative to the other end opening of the branch passage section 3a, can be performed solely by the sliding operation of the slide plate 42. Therefore, the connection switching mechanism 4 has a simple structure, resulting in a low-cost and less prone-to-failure spot welding electrode replenishment device 1. In addition, since the second guide cylinder 7 is made of a material with lower frictional resistance than the first guide cylinder 6, the electrode T located in the second guide cylinder 7 moves more easily than the electrode T located in the first guide cylinder 6. Therefore, the movement speed of the electrode T as it moves through the first guide cylinder 6, which receives compressed air at the fitting recess T1 on the base end side of the electrode T, resulting in less energy loss from the compressed air to the electrode T, and the movement speed of the electrode T as it moves through the second guide cylinder 7, which receives compressed air at the hemispherical portion on the tip end side of the electrode T, resulting in greater energy loss from the compressed air to the electrode T, become the same or approach each other. This suppresses variations in the movement of each electrode T on the first electrode storage device 10A side and the second electrode storage device 10B side, preventing uneven deterioration of the spot welding electrode replenishment device 1 caused by the movement of each electrode T.

[0043] Furthermore, since the middle section of the first guide cylinder 6 is made of urethane material and the middle section of the second guide cylinder 7 is made of Teflon® material, the first guide cylinder 6 and the second guide cylinder 7 can be made from relatively easy-to-process and readily available materials, resulting in an inexpensive spot welding electrode replenishment device 1. In addition, each replenishment electrode T, which is aligned by the parts feeder 51 and sequentially sent to the device body 2, can be accurately fed one by one in the same orientation to the branch passage section 3a via the first passage section 3b and the second passage section 3c. Therefore, the replenishment of each electrode T to the first electrode storage device 10A and the second electrode storage device 10B can be performed efficiently.

[0044] In the embodiment of the present invention, the compressed air introduced from the first air introduction part 8 and the compressed air introduced from the second air introduction part 9 are set to the same flow rate, and the second guide cylinder body 7 is made of a material with lower frictional resistance than the first guide cylinder body 6. However, the present invention is not limited thereto. For example, the first guide cylinder body 6 and the second guide cylinder body 7 may be made of the same material, and the flow rate of the compressed air in the second air introduction part 9 may be set to be larger than that in the first air introduction part 8. By doing so, the energy applied to the electrode T located in the first guide cylinder body 6 from the compressed air becomes smaller, while the energy applied to the electrode T located in the second guide cylinder body 7 from the compressed air becomes larger. Therefore, the moving speed of the electrode T moving the first guide cylinder body 6, in which the loss of energy applied to the electrode T from the compressed air due to receiving the compressed air in the fitting recess T1 on the base end side of the electrode T is small, and the moving speed of the electrode T moving the second guide cylinder body 7, in which the loss of energy applied to the electrode T from the compressed air due to receiving the compressed air in the hemispherical portion on the tip end side of the electrode T is large, are the same or approach each other. Thus, it is possible to suppress the variation in the movement of each electrode T on the first electrode storage device 10A side and the second electrode storage device 10B side, and prevent the progress of deterioration of the spot welding electrode replenishing device 1 caused by the movement of each electrode T from being biased.

[0045] Furthermore, in the embodiments of the present invention, the material of the middle section of the first guide cylinder 6 is urethane, and the material of the middle section of the second guide cylinder 7 is Teflon®. However, it is not necessary for all parts to be made of these materials. For example, the first guide cylinder 6 may be formed of urethane, and the second guide cylinder 7 may be formed of Teflon®, at least including its inner circumferential surface. Also, in the embodiments of the present invention, the material of the middle section of the first guide cylinder 6 is urethane, and the material of the middle section of the second guide cylinder 7 is Teflon®. However, the second guide cylinder 7 may be made of other materials as long as it is made of a material with lower frictional resistance than the first guide cylinder 6. Furthermore, in the embodiments of the present invention, the connection switching mechanism 4 switches the connection between the lower end opening of the branch passage section 3a and the other end opening of the second guide cylinder 7 and the air inlet 8a of the first air introduction section 8. However, for example, a similar structure may be provided on the first guide cylinder 6 side. In other words, the structure may be such that it is possible to switch between connecting the other end opening of the first guide cylinder 6 to the upper end opening of the branch passage section 3a and connecting the second air introduction section 9. In this case, the movement of the electrode T located in the branch passage section 3a to the second guide cylinder 7 can be performed using the compressed air from the second air introduction section 9. In addition, in the embodiment of the present invention, the electrodes T stored in the first electrode storage device 10A and the second electrode storage device 10B are each stored one by one, but the structure is not limited to this, and a structure in which multiple electrodes T are stored in the storage passage 11a may be used. Furthermore, in the embodiment of the present invention, the sliding operation of the slide plate 42, the pressing operation of the pressing block 52b, and the mechanism for blocking the passage of the first passage section 3b are performed by the first air cylinder 43, the second air cylinder 52, and the third air cylinder 53, respectively, but these can be replaced with other actuators such as electric cylinders and hydraulic cylinders.

[0046] The present invention is suitable for a spot welding electrode replenishment device that automatically replenishes electrodes in an electrode storage device that stores replacement electrodes to be attached to a spot welding gun.

[0047] 1 Spot welding electrode replenishment device 2 Device body 3 Body frame 3a Branching passage section 3b First passage section 3c Second passage section 4 Connection switching mechanism 5 Electrode set section 6 First guide cylinder 6a First connecting cylinder section 6b First flexible cylinder section 7 Second guide cylinder 7a Second connecting cylinder section 7b Second flexible cylinder section 8 First air introduction section 8a Air inlet 9 Second air introduction section 10A First electrode storage device 10B Second electrode storage device 11 Storage case 11a Storage passage 11b Electrode outlet 11c Ball plunger 12 Pressing mechanism 13 Pressing air cylinder 13a Hollow section 13b Guide hole 13c First air introduction hole 13d Second air introduction hole 14 Piston 15 Rod member 16 Pressing member 41 Support frame 42 Slide plate 42a First through hole 42b Second through hole 43 First air cylinder 43a First piston rod 51 Parts feeder 51a Bowl section 51b Electrode guide section 52 Second air cylinder 52a Second piston rod 52b Pressing block 53 Third air cylinder 53a Third piston rod 54 Electrode detection sensor 91 Connection block 91a Communication hole section 92 Air introduction tube G Spot welding gun G1 Shank T Electrode T1 Fitting recess X1 Electrode removal device

Claims

1. A spot welding electrode replenishment device for replenishing electrodes from the same direction to first and second electrode storage devices that store a pair of electrodes to be attached to a spot welding gun in opposite orientations, the device having a branched passage section with openings at both ends inside, and a device body that moves the electrode located in the branched passage section to either one of the two orientations such that its central axis is aligned with the branched passage section; an electrode setting section that can set the electrode in the branched passage section such that its central axis is aligned with the branched passage section; a first guide cylinder, one end of which is connected to the first electrode storage device and the other end of which is configured to be connectable to one end opening of the branched passage section, and capable of guiding the electrode; a second guide cylinder, one end of which is connected to the second electrode storage device and the other end of which is configured to be connectable to the other end opening of the branched passage section, and capable of guiding the electrode; and a first air introduction section into the first guide cylinder that can introduce compressed air toward the first electrode storage device. A spot welding electrode replenishment device characterized by comprising a second air introduction section that allows compressed air toward the second electrode storage device to be introduced inside the second guide cylinder.

2. The spot welding electrode replenishment device according to claim 1, wherein the device body comprises a main body frame having a branch passage portion extending linearly vertically, and a connection switching mechanism for switching the connection between the other end opening of the second guide cylinder and the air inlet of the first air inlet portion to the other end opening of the branch passage portion, wherein the other end opening of the first guide cylinder is connected to one end opening of the branch passage portion, and the second air inlet portion is connected to a position closer to the other end of the second guide cylinder.

3. The spot welding electrode replenishment device according to claim 2, wherein the connection switching mechanism comprises a slide plate fixed in a position such that the other end opening of the second guide cylinder and the air inlet of the first air introduction section face upward, and a first actuator that slides the slide plate horizontally, wherein the sliding operation of the slide plate toward one side connects the other end opening of the second guide cylinder to the other end opening of the branch passage section, and the sliding operation of the slide plate toward the other side connects the air inlet of the first air introduction section to the other end opening of the branch passage section.

4. A spot welding electrode replenishment device according to any one of claims 1 to 3, wherein the electrode setting section sets the electrode in the branching passage section such that the tip side faces the first guide cylinder, and the second air introduction section is set to have a larger flow rate of compressed air introduced than the first air introduction section.

5. Spot welding electrode replenishment device according to any one of claims 1 to 3, wherein the electrode set section sets the electrode in the branch passage section such that the tip side faces the first guide cylinder, the compressed air introduced from the first air introduction section and the compressed air introduced from the second air introduction section are set to the same flow rate, and the portion of the second guide cylinder including at least the inner circumferential surface is made of a material with lower frictional resistance than the portion of the first guide cylinder including at least the inner circumferential surface.

6. Spot welding electrode replenishment device according to claim 5, characterized in that the middle portion of the first guide cylinder is made of urethane material, and the middle portion of the second guide cylinder is made of Teflon® material.

7. Spot welding electrode replenishment device according to claim 2 or 3, wherein the main frame comprises a first passage portion extending in a horizontal direction perpendicular to the branch passage portion and having one end communicating with the branch passage portion, and a second passage portion extending in a horizontal direction perpendicular to the first passage portion and having one end communicating with the other end of the first passage portion, and the electrode set portion comprises a parts feeder that sequentially supplies the electrodes to the second passage portion, and a second actuator that presses the electrodes located in the portion of the second passage portion that communicates with the first passage portion toward one end of the first passage portion in a direction along the first passage portion.

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