Electrode replenishing system for spot welding

Abstract

Each electrode replenishment unit (3) comprises a body frame, an electrode feeder (2), and a connection switching mechanism. The connection switching mechanism switches the connection of a first electrode replenishment cylindrical body (6A), a second electrode replenishment cylindrical body (6B), and an electrode discharge cylindrical body (7) to a second electrode outlet. The downstream end of the electrode discharge cylindrical body (7), the upstream end of which is connected to a first electrode replenishment unit (3A), is connected to the body frame of a second electrode replenishment unit (3B), and the downstream end of an electrode supply cylindrical body (5), the upstream end of which is connected to the electrode feeder (2), is connected to the body frame of the first electrode replenishment unit (3A).

Description

Spot Welding Electrode Replenishment System

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

[0002] Conventionally, in a spot welding gun, an electrode that sandwiches and pressurizes and energizes a welding object during welding is attached to the shank portion of the gun body by fitting, and this electrode 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 storage cases arranged in parallel such that fitting recesses that fit into the shank portion of the spot welding gun open in the same direction, and this storage case is detachable from the main body portion of the device.

[0003] By the way, when each electrode in the storage case of the above-described electrode storage device runs out or decreases, it is necessary to exchange it with a spare storage case in which a plurality of electrodes are stored in advance.

[0004] However, the work of exchanging the storage case of each electrode storage device requires an operator to stop the operation of the production line and enter the inside to perform the work, resulting in a problem of poor production efficiency. Also, from the perspective of safety management, there is a demand to reduce the work performed by the operator entering the production line as much as possible.

[0005] In order 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 to the storage case of each electrode storage device in sequence.

[0006] Japanese Patent No. 6236192

[0007] By the way, in a production line where spot welding work is performed, a large number of robots holding spot welding guns are arranged, and one electrode storage device is required for several robots.

[0008] However, since typical parts feeders supply one electrode at a time, implementing them would require installing a separate parts feeder for each electrode storage device, necessitating a large installation space and resulting in high equipment costs.

[0009] The present invention has been made in view of the above, and its objective is to provide a spot welding electrode replenishment system that can increase production efficiency even in a production line with a large number of spot welding guns, reduce the amount of work performed by workers on the production line, and furthermore, make effective use of space at low cost.

[0010] To achieve the above objective, the present invention is characterized by connecting multiple electrode replenishment units capable of replenishing electrodes to an electrode storage device in series, connecting one electrode feeder to the upstream end, and replenishing electrodes to the electrode storage device that needs replenishment by sequentially supplying each electrode from the electrode feeder through each electrode replenishment unit.

[0011] Specifically, the following measures were taken for a spot welding electrode replenishment system that includes an electrode storage device for storing and preparing replacement electrodes to be attached to a spot welding gun, and multiple electrode replenishment units for replenishing the electrodes.

[0012] In other words, the spot welding electrode replenishment system according to the first invention comprises, each electrode replenishment unit, a main frame provided with an electrode branching passage having an electrode inlet and an electrode outlet, an electrode feeder to which the upstream end of an electrode supply cylinder is connected and which can supply electrodes one by one with compressed air via the electrode supply cylinder, a connection switching mechanism to which the upstream end of the electrode replenishment cylinder and the upstream end of an electrode discharge cylinder are fixed and which switches the connection between the electrode replenishment cylinder and the electrode discharge cylinder to the electrode outlet, and an air unit capable of flowing compressed air downstream inside the electrode replenishment cylinder or the electrode discharge cylinder, wherein the downstream end of the electrode replenishment cylinder is connected to the electrode storage device, the downstream end of the electrode discharge cylinder in each electrode replenishment unit arranged sequentially from upstream to downstream is connected to the electrode inlet of the next downstream electrode replenishment unit, and the downstream end of the electrode supply cylinder is connected to the electrode inlet of the electrode replenishment unit located at the upstream end.

[0013] In this configuration, the spot welding electrode replenishment system operates so that a single electrode feeder can replenish electrodes for all electrode storage devices. Furthermore, it allows for electrode replenishment even when the operator is outside the production line.

[0014] The spot welding electrode replenishment system according to the second invention is characterized in that, in the first invention, the connection switching mechanism comprises a slide plate to which the upstream end of the electrode replenishment cylinder and the upstream end of the electrode discharge cylinder are fixed, and a first actuator that slides the slide plate in the direction in which the electrode replenishment cylinder and the electrode discharge cylinder are arranged side by side, wherein the sliding operation of the slide plate toward one side connects the upstream end of the electrode replenishment cylinder to the electrode outlet, and the sliding operation of the slide plate toward the other side connects the upstream end of the electrode discharge cylinder to the electrode outlet.

[0015] In this spot welding electrode replenishment system, the switching operation between the upstream end of the electrode replenishment cylinder and the upstream end of the electrode discharge cylinder relative to the electrode outlet of the electrode branching passage is performed solely by a sliding motion of a slide plate.

[0016] The third electrode replenishment system for spot welding according to the third invention is provided in the second invention, wherein the electrode storage device is arranged in a pair so as to be able to store a pair of electrodes to be attached to the spot welding gun in opposite orientations for one electrode replenishment unit, the electrodes introduced into the electrode branch passage from the electrode inlet of the main frame are set in the electrode branch passage with their central axis extending vertically, the electrode outlet comprises a first electrode outlet opening upward and a second electrode outlet opening downward below the first electrode outlet, and the electrode replenishment cylinder is provided in a pair, with one upstream end connected to the first electrode outlet and the other downstream end connected from above to one of the electrode storage devices. Furthermore, the upstream end of the other is connected to the slide plate, while the downstream end of the other is connected from above to the other electrode storage device, and the air unit comprises a first air introduction section that can introduce compressed air toward the one electrode storage device into the inside of one electrode replenishment cylinder, a second air introduction section that can introduce compressed air toward the other electrode storage device into the inside of the other electrode replenishment cylinder, and a third air introduction section that can introduce compressed air into the inside of the electrode discharge cylinder, wherein the first air introduction section is connected to the slide plate, and the air inlet of the first air introduction section is connected to or disconnected from the second electrode outlet by the sliding movement of one or the other side of the slide plate.

[0017] In this configuration of a spot welding electrode replenishment device, the electrodes are replenished in such a way that their orientation is reversed when replenishing one electrode storage device and when replenishing the other electrode storage device. Furthermore, all electrode supply destinations are switched using a single connection switching mechanism.

[0018] The spot welding electrode replenishment system according to the fourth invention is characterized in that, in the third invention, the first air introduction section, the electrode replenishment cylinder, and the electrode discharge cylinder are connected to the slide plate in a row in order along the sliding direction at a predetermined interval, and an L-shaped overhang is attached to the upstream end opening of the electrode discharge cylinder from above.

[0019] In the spot welding electrode replenishment device configured in this way, when the first air inlet or the upstream end of the other electrode replenishment cylinder is connected to the second electrode outlet opening, the device operates in such a way that the upstream end opening of the electrode discharge cylinder is covered by the overhang.

[0020] The fifth electrode replenishment system for spot welding according to the third or fourth invention is characterized in that, in the third or fourth invention, the electrode inlet is arranged in parallel with the first electrode outlet, opens upward, and is configured to introduce the electrode in a position where its central axis is oriented vertically, and a second actuator having a pressing portion capable of pressing the electrode introduced from the electrode inlet to the space between the first electrode outlet and the second electrode outlet of the electrode branching passage is disposed on the side of the electrode branching passage.

[0021] In this configuration, the spot welding electrode replenishment device works to efficiently set each electrode sent to the electrode replenishment unit between the first electrode outlet and the second electrode outlet in the electrode branching passage.

[0022] In the spot welding electrode replenishment system of the first invention, each electrode of the electric feeder is first supplied via an electrode supply cylinder to the electrode replenishment unit located at the uppermost position of each electrode replenishment unit connected in series, and is introduced into the electrode branch passage of that electrode replenishment unit via an electrode inlet. If the introduced electrode requires replenishment in the electrode storage device connected to that electrode replenishment unit, the electrode replenishment cylinder is connected to the electrode outlet by a connection switching mechanism, and compressed air from an air unit supplies the electrode located in the electrode branch passage to the electrode storage device via the electrode replenishment cylinder. On the other hand, if the introduced electrode does not require replenishment in the electrode storage device connected to that electrode replenishment unit, the electrode discharge cylinder is connected to the electrode outlet by a connection switching mechanism, and compressed air from an air unit sends the electrode located in the electrode branch passage to the next downstream electrode replenishment unit via the electrode discharge cylinder. The electrode introduced into the downstream electrode replenishment unit is then replenished in the electrode storage device connected to that electrode replenishment unit if replenishment is required, and sent to the next downstream electrode replenishment unit if it is not required. In this way, a single electrode feeder can replenish electrodes for all electrode storage devices, eliminating the need to install a separate electrode feeder for each electrode storage device. This allows for efficient use of space and lowers equipment costs. Furthermore, electrodes can be replenished in the electrode storage devices even when workers are outside the production line. Therefore, even if an electrode storage device runs out of electrodes or the number of electrodes decreases, workers no longer need to enter the production line to replace the housing cases of the 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.

[0023] In the spot welding electrode replenishment system of the second invention, the switching operation between the upstream end of the electrode replenishment cylinder and the upstream end of the electrode discharge cylinder relative to the electrode outlet of the electrode branching passage can be performed solely by a sliding operation of a slide plate. Therefore, the connection switching mechanism has a simple structure, making it possible to create a low-cost and less prone-to-failure device.

[0024] In the third invention's spot welding electrode replenishment system, the connection switching mechanism connects the air inlet of the first air inlet to the second electrode outlet of the electrode branching passage, and when compressed air is introduced from the first air inlet, the electrode set between the first and second electrode outlets of the electrode branching passage is ejected from the first electrode outlet and moves to one of the electrode replenishment cylinders. Subsequently, as the introduction of compressed air by the first air inlet continues, the electrode is pushed by the compressed air and guided to one of the electrode replenishment cylinders, moving toward one of the electrode storage devices. On the other hand, the connection switching mechanism connects the upstream end of the other electrode replenishment cylinder to the second outlet opening of the electrode branching passage, and when an electrode is set between the first and second electrode outlets of the electrode branching passage, the electrode falls from the electrode branching passage and moves toward the other electrode replenishment cylinder. Subsequently, when compressed air is introduced into the other electrode replenishment cylinder, the electrode is pushed by the compressed air and guided to the other electrode replenishment cylinder, moving toward the other electrode storage device. Furthermore, by connecting the upstream end of the electrode discharge cylinder to the second electrode outlet of the electrode branching passage using the connection switching mechanism, and setting an electrode between the first and second electrode outlets of the electrode branching passage, the electrode will fall from the electrode branching passage and move into the electrode discharge cylinder. Subsequently, when compressed air is introduced into the electrode discharge cylinder, the electrode will be pushed by the compressed air and guided into the electrode discharge cylinder towards the next electrode replenishment unit located downstream. In this way, the direction of the electrodes can be changed when replenishing one electrode storage device and when replenishing the other electrode storage device. In addition, since all electrode supply destinations can be switched with a single connection switching mechanism, a low-cost structure can be achieved.

[0025] In the spot welding electrode replenishment system of the fourth invention, when the first air inlet or the upstream end of the other electrode replenishment cylinder is connected to the second electrode outlet, the upstream end opening of the electrode discharge cylinder is covered by the overhang. Therefore, it becomes difficult for dirt and dust to enter the electrode discharge cylinder, and the electrode can pass smoothly through the electrode discharge cylinder even when the system is used repeatedly.

[0026] In the fifth invention, the spot welding electrode replenishment system allows each electrode sent to the electrode replenishment unit to be efficiently set between the first electrode outlet and the second electrode outlet in the electrode branching passage. Therefore, the replenishment of each electrode to both electrode storage devices and the subsequent downstream electrode replenishment unit can be carried out smoothly.

[0027] This is a perspective view showing a spot welding electrode replenishment system and two electrode exchange devices according to an embodiment of the present invention. This is a perspective view showing the electrode feeder of the spot welding electrode replenishment system according to an embodiment of the present invention. This is a cross-sectional view taken along line III-III in Figure 2. This is a cross-sectional view taken along line IV-IV in Figure 3. This is a diagram showing the state immediately before the start of electrode replenishment to the electrode replenishment unit after Figure 4. This is a perspective view showing the electrode replenishment unit of the spot welding electrode replenishment system according to an embodiment of the present invention. This is a cross-sectional view taken along line VII-VII in Figure 6. This is a cross-sectional view taken along line VIII-VIII in Figure 7. This is a diagram showing the state immediately before the electrode is replenished from the first electrode replenishment unit to one of the pair of electrode storage devices after Figure 7. This is a diagram showing the state immediately before the electrode is replenished from the first electrode replenishment unit to the other of the pair of electrode storage devices after Figure 7. This is a diagram showing the state immediately before the electrode is replenished from the first electrode replenishment unit to the second electrode replenishment unit after Figure 7. This is a cross-sectional view of the second electrode replenishment unit corresponding to Figure 7. This is a perspective view showing an electrode exchange device. This is a cross-sectional view taken along line XIV-XIV in Figure 13. This is a diagram showing the state immediately after the electrode replenished in one of the electrode storage devices has been transferred to the electrode removal position after Figure 14. This is a cross-sectional view along the line XVI-XVI in Figure 15. This is a cross-sectional view along the line XVII-XVII in Figure 13. This figure shows the state immediately after the electrodes replenished in the other electrode storage device have been transferred to the electrode removal position, as shown in Figure 17.

[0028] 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.

[0029] Figure 1 shows a spot welding electrode replenishment system 1 according to an embodiment of the present invention, and a pair of electrode replacement devices X that replace electrodes T with those used in a spot welding gun G. The spot welding electrode replenishment system 1 automatically replenishes the electrodes T used in the pair of electrode replacement devices X, and is installed on an automobile production line.

[0030] The spot welding electrode replenishment system 1 comprises an electrode feeder 2 capable of supplying electrodes T one at a time, and a pair of electrode replenishment units 3 for replenishing electrodes T to each electrode replacement device X, with the electrode feeder 2 and the two electrode replenishment units 3 connected in series in sequence.

[0031] For convenience, in the following, the electrode replenishment unit 3 corresponding to the electrode replacement device X located upstream will be referred to as the first electrode replenishment unit 3A, and the electrode replenishment unit 3 corresponding to the electrode replacement device X located downstream will be referred to as the second electrode replenishment unit 3B.

[0032] As shown in Figure 2, the electrode feeder 2 includes a feeder case 21 that is roughly rectangular in shape and extends vertically. The top surface of the feeder case 21 is provided with a door 21a into which a large number of electrodes T can be inserted before use, an operation monitor 21b for operating the electrode feeder 2, and an emergency button 21c for stopping the electrode feeder 2 in an emergency.

[0033] Inside the feeder case 21, as shown in Figure 3, there is a bowl portion 22 that opens upward and can store a number of electrodes T, and an electrode guide portion 23 with a concave cross-section that extends substantially in a straight line from a part of the upper end periphery of the bowl portion 22 to the front surface of the feeder case 21. The tip of the electrode guide portion 23 faces the outside of the feeder case 21 through a case opening 21d formed on the front surface of the feeder case 21.

[0034] The bowl portion 22 is configured to be rotatable about a rotation axis C1 that extends vertically. As the bowl portion 22 rotates about the rotation axis C1, each electrode T stored in the bowl portion 22 is guided by the electrode guide portion 23, aligning in a straight line with its tip facing upward, and is sequentially supplied to the outside of the feeder case 21 through the case opening 21d.

[0035] A feeder unit 4 is mounted via a case bracket 21e at a position corresponding to the case opening 21d on the front of the feeder case 21, for supplying each electrode T one by one to the electrode exchange device X located upstream.

[0036] As shown in Figures 3 and 4, the feeder unit 4 includes a feeder body 41 which has a substantially rectangular parallelepiped shape and extends horizontally along the front of the feeder case 21, a first pressing air cylinder 42 fixed to one end in the longitudinal direction of the feeder body 41, a first gate air cylinder 43 fixed to the side of the feeder body 41 that is farther from the feeder case 21, and a first electrode detection sensor 44 arranged in parallel with the first gate air cylinder 43.

[0037] Inside the feeder body 41, a first passage portion 41a is formed that extends horizontally along the longitudinal direction of the feeder body 41. This first passage portion 41a is shaped to open at one end in the longitudinal direction of the feeder body 41 and to open upward from that end to the middle of the longitudinal direction.

[0038] A second passage portion 41b is formed in the middle of the longitudinal direction of the feeder body 41, extending horizontally in the width direction of the feeder body 41 and communicating with the first passage portion 41a. The second passage portion 41b has a concave cross-section that opens upward, and is designed to receive the electrode T supplied from the bowl portion 22 via the electrode guide portion 23 into the inside of the feeder body 41.

[0039] Furthermore, an electrode outlet portion 41c communicating with the first passage portion 41a is formed on the upper surface of the other end of the feeder body 41 in the longitudinal direction, while an air supply opening 41d communicating with the first passage portion 41a is formed on the lower surface of the other end of the feeder body 41 in the longitudinal direction, and the electrode outlet portion 41c and the air supply opening 41d are in a positional relationship that corresponds vertically.

[0040] The first pressing air cylinder 42 is equipped with a first pressing piston rod 42a that can extend and retract within the first passage 41a along the longitudinal direction of the feeder body 41. A first pressing block 45, which has a shape corresponding to the first passage 41a, is fixed to the tip of this first pressing piston rod 42a. When the first pressing piston rod 42a extends, as shown in Figures 4 and 5, the first pressing block 45 presses the electrode T located in the portion of the second passage 41b that communicates with the first passage 41a toward the other end of the feeder body 41 along the longitudinal direction, along the first passage 41a. The electrode T pressed by the first pressing block 45 is then set in a position corresponding to the electrode outlet 41c of the first passage 41a, with its centerline aligned vertically and its tip facing upward.

[0041] The first gate air cylinder 43 is equipped with a first gate pin 43a that is extendable and retractable along the width direction of the feeder body 41 so as to obstruct the first passage portion 41a, and this first gate pin 43a is positioned along the inner wall of the second passage portion 41b on the side furthest from the first pressing air cylinder 42. The first gate air cylinder 43 is configured such that when the first gate pin 43a is extended, as shown in Figures 3 and 4, the first gate pin 43a obstructs the first passage portion 41a, preventing the electrode T from passing through the first passage portion 41a, and when the first gate pin 43a is retracted, the first gate pin 43a is no longer positioned in the first passage portion 41a, allowing the electrode T to pass through the first passage portion 41a.

[0042] The first electrode detection sensor 44 is capable of detecting whether or not the electrode T is located in the portion of the second passage portion 41b that communicates with the first passage portion 41a.

[0043] The upstream end of the electrode supply cylinder 5, whose main body is formed of a flexible resin material, is connected to the electrode outlet 41c of the feeder main body 41 via a connecting member 5a having a short cylindrical shape.

[0044] Further, a feeder air introduction part 46 capable of introducing compressed air into the first passage part 41a is connected to the air supply opening 41d of the feeder main body 41. When compressed air is introduced into the first passage part 41a by the feeder air introduction part 46, the electrode T set at a position corresponding to the electrode outlet 41c of the first passage part 41a rises and moves to the electrode supply cylinder 5 through the air supply opening 41d as shown in FIG. 5.

[0045] As shown in FIG. 1, the first electrode replenishment unit 3A is fixed to the back side of the electrode changer X located on the upstream side. As shown in FIGS. 1, 6, and 7, the first electrode replenishment unit 3A includes a main body frame 31 having a substantially rectangular parallelepiped block shape that extends horizontally away from the back side of the electrode changer X located on the upstream side, a connection switching mechanism 32 disposed below the main body frame 31, and a cover member 30 that is arranged in parallel with the main body frame 31 and covers a part above the connection switching mechanism 32.

[0046] The main body frame 31 is composed of a first block 31A in the upper half and a second block 31B in the lower half.

[0047] A first through hole 31a penetrating vertically is formed at one end in the longitudinal direction of the first block 31A. The lower part of the first through hole 31a has a tapered shape with a reduced diameter toward the lower end as shown in FIG. 7.

[0048] The downstream end side of the electrode supply cylinder 5 is fitted into a portion extending from the upper end to the middle part of the first through hole 31a, and the electrode T supplied from the electrode feeder 2 drops downward from the lower end opening of the first through hole 31a.

[0049] Further, a step surface part 31b with a shallow step is formed on the lower surface at the center in the width direction on the other end side in the longitudinal direction of the first block 31A, and a second through hole 31c penetrating vertically from the upper surface to the step surface part 31b is formed on the other end side in the longitudinal direction of the first block 31A.

[0050] The lower part of the second through-hole 31c has an inverse tapered shape that widens towards the bottom end, and the upstream side of the first electrode replacement cylinder 6A, whose main body is made of a flexible resin material, is fitted into the portion of the second through-hole 31c from the upper end to the middle.

[0051] Inside the second block 31B, an electrode branching passage 31d is formed that extends horizontally along the longitudinal direction of the second block 31B. This electrode branching passage 31d is shaped to open at one end in the longitudinal direction of the second block 31B and to open upward from that end towards the other end in the longitudinal direction.

[0052] The position where the electrode branching passage 31d opens upward towards the other end in the longitudinal direction corresponds to the second through hole 31c of the first block 31A, and constitutes the first electrode outlet 31e of the present invention.

[0053] Furthermore, the position where the electrode branching passage 31d opens above the midpoint in the longitudinal direction corresponds to the first through hole 31a of the first block 31A, and constitutes the electrode inlet 31g of the present invention. That is, the electrode inlet 31g is arranged in parallel with the first electrode outlet 31e and is designed to guide the electrode T falling from the lower end opening of the first through hole 31a, to which the downstream end of the electrode supply cylinder 5 is connected, into the electrode branching passage 31d in an orientation where its central axis is oriented vertically.

[0054] A second electrode outlet 31f is formed on the lower surface of the other end in the longitudinal direction of the electrode branching passage 31d, penetrating vertically. The second electrode outlet 31f is in a positional relationship with the first electrode outlet 31e vertically, and in the electrode branching passage 31d, the first electrode outlet 31e and the second electrode outlet 31f open in opposite directions to each other.

[0055] The other end of the first block 31A in the longitudinal direction protrudes beyond the other end of the second block 31B in the longitudinal direction, and a plate-shaped gap space S1 is formed between the stepped surface portion 31b of the first block 31A and the upper surface on the other end side of the second block 31B in the longitudinal direction.

[0056] A second pressing air cylinder 33 (second actuator) is fixed to one longitudinal end of the second block 31B, that is, to the side of the electrode branching passage 31d. The second pressing air cylinder 33 is equipped with a second pressing piston rod 33a (pressing part) that can extend and retract within the electrode branching passage 31d along the longitudinal direction of the second block 31B.

[0057] A second pressing block 33b, shaped to match the electrode branching passage 31d, is fixed to the tip of the second pressing piston rod 33a. When the second pressing piston rod 33a extends, as shown in Figures 7 to 9, the second pressing block 33b presses the electrode T located in the region corresponding to the electrode inlet 31g of the electrode branching passage 31d toward the other end in the longitudinal direction of the second block 31B along the electrode branching passage 31d. The electrode T pressed by the second pressing block 33b is then set between the first electrode outlet 31e and the second electrode outlet 31f of the electrode branching passage 31d with its centerline aligned vertically and its tip facing downwards.

[0058] As shown in Figure 6, a second gate air cylinder 34 is attached to one outer surface in the width direction of the second block 31B. As shown in Figure 7, this second gate air cylinder 34 is equipped with a second gate pin 34a that can extend and retract to block the electrode branch passage portion 31d along the width direction of the second block 31B, and this second gate pin 34a is positioned near the edge of the lower end opening of the first through hole 31a that is farther away from the second pressing air cylinder 33. The second gate air cylinder 34 is configured such that when the second gate pin 34a is extended, the second gate pin 34a blocks the electrode branch passage portion 31d, preventing the electrode T from passing through the electrode branch passage portion 31d, and when the second gate pin 34a is retracted, the second gate pin 34a is no longer positioned in the electrode branch passage portion 31d, allowing the electrode T to pass through the electrode branch passage portion 31d.

[0059] As shown in Figure 6, a second electrode detection sensor 35 is attached to the outer surface of the second block 31B on the other side in the width direction. This second electrode detection sensor 35 is capable of detecting whether or not the electrode T is located in the region corresponding to the electrode inlet 31g in the electrode branching passage 31d.

[0060] The connection switching mechanism 32 includes a pair of support frames 36a that extend in the longitudinal direction of the second block 31B and are fixed to the lower surface of the second block 31B, spaced apart in the width direction of the second block 31B, with one end of each support frame 36a in the longitudinal direction connected by a bridging frame 36b.

[0061] As shown in Figure 7, a slide plate 37, which is rectangular in shape in plan view, is positioned between the two support frames 36a, and a sliding air cylinder 38 (first actuator) is fixed to the other end of the two support frames 36a in the longitudinal direction.

[0062] A first opening 37a is formed in the center of one longitudinal side of the slide plate 37, and a first air inlet 39a is connected to the first opening 37a such that the air inlet faces upward.

[0063] Furthermore, a second opening 37b is formed near one side of the middle of the slide plate 37 in the longitudinal direction, and the upstream side of a second electrode replenishment cylinder 6B, whose main body is made of a flexible resin material, is connected to the second opening 37b from below by a first connecting pipe 6a of the second electrode replenishment cylinder 6B.

[0064] Furthermore, a third opening 37c is formed on the other longitudinal side of the slide plate 37, and the upstream side of an electrode discharge cylinder 7, whose main body is made of a flexible resin material, is connected to the third opening 37c from below by a second connecting pipe 7a of the electrode discharge cylinder 7.

[0065] In other words, the first air introduction section 39a, the second electrode replenishment cylinder 6B, and the electrode discharge cylinder 7 are connected to the slide plate 37 in order and in a line at predetermined intervals along the sliding direction.

[0066] A second air introduction section 6b is connected to the first connecting pipe 6a of the second electrode replenishment cylinder 6B, allowing compressed air to be introduced into the second electrode replenishment cylinder 6B. The second air introduction section 6b has a first communication hole 6c that extends linearly diagonally downward and communicates with the inside of the first connecting pipe 6a, allowing compressed air to be introduced into the second electrode replenishment cylinder 6B toward the downstream side of the second electrode replenishment cylinder 6B.

[0067] Furthermore, a third air introduction section 7b is connected to the second connecting pipe 7a of the electrode discharge cylinder 7, which allows compressed air to be introduced into the electrode discharge cylinder 7. The third air introduction section 7b has a second communication hole 7c that extends linearly diagonally downward and communicates with the inside of the second connecting pipe 7a, allowing compressed air to be introduced into the inside of the electrode discharge cylinder 7 toward the downstream side of the electrode discharge cylinder 7.

[0068] The first air introduction section 39a, the second air introduction section 6b, the third air introduction section 7b, and the feeder air introduction section 46 constitute the air unit 20 of the present invention.

[0069] The sliding air cylinder 38 is extendable and retractable along the longitudinal direction of the second block 31B and includes a slide rod 38a whose tip is connected to the other end of the slide plate 37 in the longitudinal direction. When this slide rod 38a is retracted, as shown in Figure 7, the slide plate 37 slides to the other end in the longitudinal direction so that the first opening 37a connects to the second electrode outlet 31f. In other words, the slide plate 37 slides in the direction in which the second electrode replenishment cylinder 6B and the electrode discharge cylinder 7 are arranged side by side.

[0070] With the first opening 37a corresponding to the second electrode outlet 31f, as shown in Figure 9, the second gate pin 34a of the second gate air cylinder 34 is retracted and the second pressing block 33b of the second pressing air cylinder 33 is extended to set the electrode T between the first electrode outlet 31e and the second electrode outlet 31f of the electrode branching passage 31d. When compressed air is introduced into the electrode branching passage 31d by the first air introduction section 39a, the electrode T moves to the first electrode replenishment cylinder 6A via the first electrode outlet 31e.

[0071] Furthermore, as shown in Figure 10, when the slide plate 37 is extended with the first opening 37a connected to the second electrode outlet 31f, it slides to one side in the longitudinal direction so that the second opening 37b connects to the second electrode outlet 31f.

[0072] With the second opening 37b connected to the second electrode outlet 31f, when the second gate pin 34a of the gate second air cylinder 34 is retracted and the second pressing block 33b of the pressing second air cylinder 33 is extended, the electrode T is set between the first electrode outlet 31e and the second electrode outlet 31f of the electrode branching passage 31d. The electrode T then falls through the second electrode outlet 31f and the second opening 37b and moves to the second electrode replenishment cylinder 6B.

[0073] When electrode T falls through the second electrode outlet 31f and the second opening 37b, compressed air is introduced from the second air inlet 6b into the second electrode replenishment cylinder 6B, causing electrode T to move downstream of the second electrode replenishment cylinder 6B.

[0074] Furthermore, as shown in Figure 11, when the slide plate 37 is further extended with the second opening 37b connected to the second electrode outlet 31f, it slides to one side in the longitudinal direction so that the third opening 37c connects to the second electrode outlet 31f.

[0075] When the third opening 37c is connected to the second electrode outlet 31f, the second gate pin 34a of the second gate air cylinder 34 is retracted and the second pressing block 33b of the second pressing air cylinder 33 is extended to set the electrode T between the first electrode outlet 31e and the second electrode outlet 31f of the electrode branching passage 31d. As a result, the electrode T falls through the second electrode outlet 31f and the third opening 37c and moves into the electrode discharge cylinder 7.

[0076] When the electrode T falls through the second electrode outlet 31f and the third opening 37c, compressed air is introduced from the third air inlet 7b into the electrode discharge cylinder 7, causing the electrode T to move downstream of the electrode discharge cylinder 7.

[0077] In this way, the connection switching mechanism 32 can switch between connecting and disconnecting the first air introduction section 39a to the second electrode outlet 31f, the upstream end of the second electrode replenishment cylinder 6B, and the upstream end of the electrode discharge cylinder 7, respectively, by the sliding operation of the slide plate 37.

[0078] As shown in Figure 7, an L-shaped overhang 37d is attached to the upper surface of the other end of the slide plate 37 in the longitudinal direction, and this overhang 37d covers the third opening hole 37c, that is, the upstream end opening of the electrode discharge cylinder 7, from above.

[0079] As shown in Figure 11, when the slide plate 37 slides to one side in the longitudinal direction, the canopy portion 37d enters the gap space S1 formed between the first block 31A and the second block 31B, and partitions the electrode branching passage portion 31d from the downstream end of the first electrode replenishment cylinder 6A.

[0080] As shown in Figure 1, the second electrode replenishment unit 3B is fixed to the rear side of the electrode replacement device X located downstream. As also shown in Figure 12, the second electrode replenishment unit 3B has the same structure as the first electrode replenishment unit 3A, except that the downstream side of the electrode discharge cylinder 7 extending from the first electrode replenishment unit 3A is fitted into the first through hole 31a of the main frame 31, and the second connecting pipe 7a connected to the third opening hole 37c is covered by a lid member 7d. Therefore, the same reference numerals are used for the same parts as in the first electrode replenishment unit 3A, and detailed explanations are omitted.

[0081] Thus, in the spot welding electrode replenishment system 1, the downstream end of the electrode discharge cylinder 7 in the first electrode replenishment unit 3A is connected to the electrode inlet 31g of the second electrode replenishment unit 3B located further downstream, and the downstream end of the electrode supply cylinder 5 extending from the electrode feeder 2 is connected to the electrode inlet 31g of the first electrode replenishment unit 3A.

[0082] As shown in Figure 1, the electrode replacement device X includes a frame 9A comprising a support column 9b extending straight upward from the center of a base plate 9a, and a control box 9c attached to the back of the support column 9b. An electrode removal unit 9B, which allows the electrode T to be removed from the spot welding gun G, is fixed to the upper surface of the support column 9b.

[0083] A first electrode storage device 10A capable of storing the electrode T with its tip facing upward is attached to one side of the electrode removal unit 9B, while a second electrode storage device 10B capable of storing the electrode T with its tip facing downward is attached to the other side of the electrode removal unit 9B.

[0084] As shown in Figures 14 and 15, the first electrode storage device 10A includes a roughly rectangular cylindrical storage case 11 that extends horizontally. Inside this storage case 11, a straight storage passage 11a is formed that extends along the longitudinal direction of the storage case 11, and the electrode T can be stored in this storage passage 11a with its central axis extending vertically and its tip facing upward.

[0085] In other words, the housing passage 11a of the first electrode storage device 10A is designed to 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 downward.

[0086] An electrode outlet 11b from which the electrode T can be removed is formed on the lower surface of one end of the housing passage 11a, and a ball plunger 11c is attached to one side of the housing passage 11a near one end, as shown in Figure 16, to press the electrode T against the other side of the housing passage 11a.

[0087] On the other hand, as shown in Figures 14 and 15, the downstream end of the first electrode replenishment cylinder 6A is connected from above to the upper surface of the other end of the housing passage 11a by the third connecting pipe 6d of the first electrode replenishment cylinder 6A, and a pressing mechanism 12 is provided at the other end of the housing passage 11a.

[0088] 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 in 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.

[0089] Furthermore, a first air inlet 13c and a second air inlet 13d are formed at positions near one end and the other end of the pressing air cylinder 13, respectively, allowing compressed air to be introduced into the hollow section 13a. These are connected to an air compressor via piping (not shown).

[0090] A disc-shaped piston 14 is provided in the hollow section 13a, dividing the hollow section 13a into two parts, and the piston 14 is slidable along the centerline of the press air cylinder 13.

[0091] A rod member 15 is integrally provided in the center of the piston 14 on the side of the housing passage 11a, extending along the centerline of the press air cylinder 13, and the rod member 15 is slidably fitted into the guide hole 13b.

[0092] A block-shaped pressing member 16, housed in a housing passage 11a, is connected to the tip of the rod member 15, and the pressing member 16 is capable of moving back and forth along the housing passage 11a.

[0093] Then, when compressed air is introduced into the hollow section 13a through the second air introduction hole 13d, as shown in Figure 15, 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 electrode replenishment cylinder 6A, to a position corresponding to the electrode outlet 11b, preparing it for attachment to the spot welding gun G.

[0094] On the other hand, when compressed air is introduced into the hollow section 13a through the first air introduction hole 13c of the pressing mechanism 12, as shown in Figure 14, the piston 14 slides away from the housing passage 11a, causing the rod member 15 to slide away from the housing passage 11a while being guided by the guide hole 13b, and the pressing member 16 returns to its original position.

[0095] As shown in Figures 17 and 18, 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 unit 9B, the storage case 11 has an inverted structure, the electrode T is housed in the storage passage 11a with its tip facing downward, and the downstream end of the second electrode replenishment cylinder 6B is connected from above to the upper surface of the other end of the storage passage 11a by the fourth connecting pipe 6e of the second electrode replenishment cylinder 6B. Therefore, the same reference numerals are used for the same parts as in the first electrode storage device 10A, and detailed explanations are omitted.

[0096] Thus, the first electrode storage device 10A and the second electrode storage device 10B store a pair of electrodes T to be attached to the spot welding gun G in opposite orientations, and the spot welding electrode replenishment system 1 can replenish electrodes T to the first electrode storage device 10A and the second electrode storage device 10B from the same direction (from above).

[0097] 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 system 1 will be described in detail.

[0098] First, the operator operates the operation monitor 21b of the electrode feeder 2 to activate the electrode feeder 2, which already has a large quantity of electrodes T stored in the bowl section 22, and rotate the bowl section 22. Then, as shown in Figure 3, each electrode T located in the bowl section 22 is guided by the electrode guide section 23 while aligning in a straight line with its tip facing upward, and is sequentially supplied to the second passage section 41b of the feeder unit 4, until the leading electrode T reaches the first passage section 41a.

[0099] Next, as shown in Figure 1, the used electrode T attached to the lower shank G1 of a predetermined spot welding gun G is removed by the electrode removal unit 9B of the electrode replacement device X located upstream. Then, the lower shank G1 of the spot welding gun G is fitted into the fitting recess T1 of the unusable 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.

[0100] When the electrode T is removed from the first electrode storage device 10A, the first gate pin 43a of the first gate air cylinder 43 of the electrode feeder 2 retracts, and then the first pressing piston rod 42a of the first pressing air cylinder 42 extends. As shown in Figures 4 and 5, the electrode T located in the second passage 41b is pressed by the first pressing block 45 and reaches the position corresponding to the electrode outlet 41c of the first passage 41a.

[0101] When the electrode T reaches the position corresponding to the electrode outlet 41c of the first passage 41a, the feeder air introduction section 46 is activated and compressed air is introduced into the first passage 41a through the air supply opening 41d, pressing the electrode T upward. Then, as shown in Figure 5, the electrode T is guided downstream by the electrode supply cylinder 5.

[0102] On the other hand, in the first electrode replenishment unit 3A attached to the electrode replacement device X located upstream, as shown in Figures 7 and 8, the sliding air cylinder 38 operates, the slide rod 38a retracts, and the first air inlet 39a connects to the second electrode outlet 31f.

[0103] When the electrode T guided by the electrode supply cylinder 5 reaches the electrode branching passage 31d of the first electrode replenishment unit 3A via the electrode inlet 31g, the second gate pin 34a of the gate second air cylinder 34 retracts, and then the pressing second piston rod 33a of the pressing second air cylinder 33 extends. As a result, as shown in Figure 9, the electrode T at the position corresponding to the electrode inlet 31g of the electrode branching passage 31d is pressed by the second pressing block 33b and reaches the space between the first electrode outlet 31e and the second electrode outlet 31f of the electrode branching passage 31d.

[0104] Then, the first air introduction section 39a is activated, and compressed air pushes the electrode T located between the first electrode outlet 31e and the second electrode outlet 31f of the electrode branching passage section 31d upwards via the second electrode outlet 31f. As a result, the electrode T is guided through the first electrode outlet 31e to the first electrode replenishment cylinder 6A, and then reaches the first electrode storage device 10A, as shown in Figure 14. In other words, the electrode T is replenished in the first electrode storage device 10A.

[0105] When the electrode T reaches the housing 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. The piston 14 and the rod member 15 slide toward the housing passage 11a, and the pressing member 16 presses the electrode T to a position corresponding to the electrode outlet 11b. The electrode T, having moved to the position corresponding to the electrode outlet 11b in the housing passage 11a, is then pressed against the wall surface of the housing passage 11a by the ball plunger 11c and held in place, entering a ready-to-install state.

[0106] Next, as shown in Figure 1, the used electrode T attached to the upper shank G1 of a predetermined spot welding gun G is removed by the electrode removal unit 9B of the electrode replacement device X located upstream. Then, the upper shank G1 of the spot welding gun G is fitted into the fitting recess T1 of the unusable 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.

[0107] When electrode T is removed from the second electrode storage device 10B, the first gate pin 43a of the first gate air cylinder 43 of the electrode feeder 2 retracts, and then the first pressing piston rod 42a of the first pressing air cylinder 42 extends. As shown in Figures 4 and 5, electrode T located in the second passage 41b is pressed by the first pressing block 45 and reaches the position corresponding to the electrode outlet 41c of the first passage 41a.

[0108] When the electrode T reaches the position corresponding to the electrode outlet 41c of the first passage 41a, the feeder air introduction section 46 is activated and compressed air is introduced into the first passage 41a through the air supply opening 41d, pressing the electrode T upward. Then, as shown in Figure 5, the electrode T is guided downstream by the electrode supply cylinder 5.

[0109] On the other hand, in the first electrode replenishment unit 3A attached to the electrode replacement device X located upstream, as shown in Figure 10, the sliding air cylinder 38 is activated, the sliding rod 38a extends, and the upstream end of the second electrode replenishment cylinder 6B connects to the second electrode outlet 31f.

[0110] When the electrode T guided by the electrode supply cylinder 5 reaches the electrode branching passage 31d of the first electrode replenishment unit 3A via the electrode inlet 31g, the second gate pin 34a of the gate second air cylinder 34 retracts, and then the pressing second piston rod 33a of the pressing second air cylinder 33 extends. As a result, the electrode T at the position corresponding to the first through hole 31a of the electrode branching passage 31d is pressed by the second pressing block 33b and reaches the space between the first electrode outlet 31e and the second electrode outlet 31f of the electrode branching passage 31d.

[0111] The electrode T that reaches the area between the first electrode outlet 31e and the second electrode outlet 31f of the electrode branching passage section 31d falls through the second electrode outlet 31f into the second electrode replenishment cylinder 6B and passes through the first connecting pipe 6a of the second air introduction section 6b. Then the second air introduction section 6b is activated and compressed air is introduced into the second electrode replenishment cylinder 6B, pressing the electrode T. The electrode T is then guided into the second electrode replenishment cylinder 6B and reaches 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.

[0112] When electrode T reaches the housing 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. The piston 14 and rod member 15 slide toward the housing passage 11a, and the pressing member 16 presses electrode T to a position corresponding to the electrode outlet 11b. Then, electrode T, having moved to the position corresponding to the electrode outlet 11b in 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 waiting state for installation.

[0113] Next, as shown in Figure 1, the used electrode T attached to the lower shank G1 of a predetermined spot welding gun G is removed by the electrode removal unit 9B of the electrode replacement device X located downstream. Then, the lower shank G1 of the spot welding gun G is fitted into the fitting recess T1 of the unusable 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.

[0114] When the electrode T is removed from the first electrode storage device 10A, the first gate pin 43a of the first gate air cylinder 43 of the electrode feeder 2 retracts, and then the first pressing piston rod 42a of the first pressing air cylinder 42 extends. As shown in Figures 4 and 5, the electrode T located in the second passage 41b is pressed by the first pressing block 45 and reaches the position corresponding to the electrode outlet 41c of the first passage 41a.

[0115] When the electrode T reaches the position corresponding to the electrode outlet 41c of the first passage 41a, the feeder air introduction section 46 is activated and compressed air is introduced into the first passage 41a through the air supply opening 41d, pressing the electrode T upward. Then, as shown in Figure 5, the electrode T is guided downstream by the electrode supply cylinder 5.

[0116] Meanwhile, in the first electrode storage device 10A and the second electrode storage device 10B, which are attached to the electrode exchange device X located upstream, the electrodes T are stored in each device. As shown in Figure 11, the sliding air cylinder 38 operates, the slide rod 38a extends, and the upstream end of the electrode discharge cylinder 7 connects to the second electrode outlet 31f. At this time, the canopy portion 37d enters the gap space S1, separating the first electrode outlet 31e from the electrode branching passage portion 31d.

[0117] When the electrode T guided by the electrode supply cylinder 5 reaches the electrode branching passage 31d of the first electrode replenishment unit 3A via the electrode inlet 31g, the second gate pin 34a of the gate second air cylinder 34 retracts, and then the pressing second piston rod 33a of the pressing second air cylinder 33 extends. As a result, the electrode T at the position corresponding to the electrode inlet 31g of the electrode branching passage 31d is pressed by the second pressing block 33b and reaches the space between the first electrode outlet 31e and the second electrode outlet 31f of the electrode branching passage 31d.

[0118] The electrode T that reaches the area between the first electrode outlet 31e and the second electrode outlet 31f of the electrode branching passage section 31d falls through the second electrode outlet 31f into the electrode discharge cylinder 7 and passes through the second connecting pipe 7a of the third air introduction section 7b. Then the third air introduction section 7b is activated and compressed air is introduced into the electrode discharge cylinder 7, pressing the electrode T. After the electrode T is guided into the electrode discharge cylinder 7, it reaches the electrode branching passage section 31d of the second electrode replenishment unit 3B, which is attached to the electrode replacement device X located downstream, via the electrode inlet 31g. The subsequent operation to put the electrode T located in the electrode branching passage section 31d into a ready-to-install state in the first electrode storage device 10A connected to the second electrode replenishment unit 3B is the same as when replenishing the electrode T in the first electrode storage device 10A connected to the first electrode replenishment unit 3A, so a detailed explanation is omitted.

[0119] Furthermore, the operation of replenishing electrodes T in the second electrode storage device 10B, which is connected to the second electrode replenishment unit 3B attached to the electrode replacement device X located downstream, is the same as when replenishing electrodes T in the second electrode storage device 10B connected to the first electrode replenishment unit 3A, so a detailed explanation is omitted.

[0120] As described above, in the electrode replenishment system 1 for spot welding according to an embodiment of the present invention, each electrode T of the electrode feeder 2 is first supplied via an electrode supply cylinder 5 to the first electrode replenishment unit 3A, which is located upstream of the first electrode replenishment unit 3A and the second electrode replenishment unit 3B, which are connected in series, and introduced into the electrode branch passage section 31d of the first electrode replenishment unit 3A via an electrode inlet 31g. When the introduced electrode T needs to be replenished in the electrode exchange device X located upstream of the first electrode replenishment unit 3A, the connection switching mechanism 32 switches between the first electrode replenishment cylinder 6A and the second electrode replenishment cylinder 6B that send the electrodes T, and compressed air from the air unit 20 supplies the electrode T located in the electrode branch passage section 31d to the first electrode storage device 10A or the second electrode storage device 10B via the first electrode replenishment cylinder 6A or the second electrode replenishment cylinder 6B.

[0121] On the other hand, if the introduced electrode T does not require replenishment in the first electrode storage device 10A and the second electrode storage device 10B connected to the first electrode replenishment unit 3A, the connection switching mechanism 32 connects the electrode discharge cylinder 7 to the second electrode outlet 31f, and the electrode T located in the electrode branching passage section 31d is sent via the electrode discharge cylinder 7 to the second electrode replenishment unit 3B located downstream by compressed air from the air unit 20. Then, if replenishment of the introduced electrode T is required in the first electrode storage device 10A and the second electrode storage device 10B connected to the second electrode replenishment unit 3B, the introduced electrode T will be replenished in the first electrode storage device 10A and the second electrode storage device 10B. In this way, a single electrode feeder 2 can replenish electrodes T to the first electrode storage device 10A and the second electrode storage device 10B, which are connected to all electrode replacement devices X. Since it is not necessary to install an electrode feeder 2 corresponding to, for example, the first electrode storage device 10A and the second electrode storage device 10B, space can be used effectively and equipment costs can be kept low. In addition, even if an operator is outside the production line, electrodes T can be replenished to the first electrode storage device 10A and the second electrode storage device 10B. Therefore, even if the electrodes T in the first electrode storage device 10A and the second electrode storage device 10B run out, it is not necessary 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.

[0122] Furthermore, the switching operation between the upstream end of the second electrode replenishment cylinder 6B and the upstream end of the electrode discharge cylinder 7 with respect to the second electrode outlet 31f of the electrode branching passage section 31d can be performed solely by the sliding operation of the slide plate 37. As a result, the connection switching mechanism 32 has a simple structure, making it possible to create a low-cost and less prone-to-failure device.

[0123] Furthermore, when the connection switching mechanism 32 connects the air inlet of the first air introduction section 39a to the second electrode outlet 31f of the electrode branching passage section 31d, and compressed air is introduced from the first air introduction section 39a, the electrode T set between the first electrode outlet 31e and the second electrode outlet 31f of the electrode branching passage section 31d will pop out of the first electrode outlet 31e and move to the first electrode replenishment cylinder 6A. Subsequently, when the introduction of compressed air by the first air introduction section 39a continues, the electrode T will be pushed by the compressed air and guided to the first electrode replenishment cylinder 6A, and will move toward the first electrode storage device 10A.

[0124] On the other hand, when the connection switching mechanism 32 connects the upstream end of the second electrode replenishment cylinder 6B to the second electrode outlet 31f of the electrode branching passage section 31d, and when the electrode T is set between the first electrode outlet 31e and the second electrode outlet 31f of the electrode branching passage section 31d, the electrode T falls from the electrode branching passage section 31d and moves into the second electrode replenishment cylinder 6B. Subsequently, when compressed air is introduced into the second electrode replenishment cylinder 6B, the electrode T is pushed by the compressed air and guided into the second electrode replenishment cylinder 6B, moving towards the second electrode storage device 10B.

[0125] Furthermore, when the upstream end of the electrode discharge cylinder 7 is connected to the second electrode outlet 31f of the electrode branching passage section 31d by the connection switching mechanism 32, and an electrode T is set between the first electrode outlet 31e and the second electrode outlet 31f of the electrode branching passage section 31d, the electrode T falls from the electrode branching passage section 31d and moves into the electrode discharge cylinder 7. Subsequently, when compressed air is introduced into the electrode discharge cylinder 7, the electrode T is pushed by the compressed air and guided into the electrode discharge cylinder 7, moving towards the second electrode replenishment unit 3B located downstream. In this way, the orientation of the electrode T can be changed when replenishing the first electrode storage device 10A and when replenishing the second electrode storage device 10B. In addition, since all supply destinations of the electrode T can be switched with a single connection switching mechanism 32, a low-cost structure can be achieved.

[0126] Furthermore, when the first air inlet 39a or the upstream end of the second electrode replenishment cylinder 6B is connected to the second electrode outlet 31f, the upstream end opening of the electrode discharge cylinder 7 is covered by the overhang 37d. Therefore, it becomes difficult for dirt and dust to enter the electrode discharge cylinder 7, and the electrode T can pass smoothly through the electrode discharge cylinder 7 even when the system is used repeatedly.

[0127] Furthermore, the electrode inlet 31g is positioned parallel to the first electrode outlet 31e, opens upward, and is configured to introduce the electrode T into the electrode branching passage 31d with its central axis facing up and down. Additionally, a second pressing air cylinder 33 having a second pressing piston rod 33a capable of pressing the electrode T to the space between the first electrode outlet 31e and the second electrode outlet 31f of the electrode branching passage 31d is provided on the side of the electrode branching passage 31d. This allows each electrode T sent to the first electrode replenishment unit 3A or the second electrode replenishment unit 3B to be efficiently set between the first electrode outlet 31e and the second electrode outlet 31f in the electrode branching passage 31d. Consequently, the replenishment of each electrode T to the first electrode storage device 10A and the second electrode storage device 10B, and the subsequent replenishment of each electrode T to the downstream second electrode replenishment unit 3B, can be performed efficiently.

[0128] In this embodiment of the present invention, the first electrode replenishment unit 3A and the second electrode replenishment unit 3B are connected in series downstream of the electrode feeder 2. However, the invention is not limited to this configuration, and a system can also be constructed in which the third electrode replenishment unit, the fourth electrode replenishment unit, ..., the nth electrode replenishment unit (where n is a natural number) are connected in series downstream of the second electrode replenishment unit 3B. That is, in a system of three or more electrode replenishment units 3 arranged sequentially from upstream to downstream, the downstream end of the electrode discharge cylinder 7 of each electrode replenishment unit 3, except for the electrode replenishment unit 3 located at the downstream end, is connected to the electrode inlet 31g of the next downstream electrode replenishment unit 3, and the downstream end of the electrode supply cylinder 5 extending from the electrode feeder 2 is connected to the electrode inlet 31g of the electrode replenishment unit 3 located at the upstream end, so that electrodes T can be efficiently replenished to all electrode replenishment units 3 with a single electrode feeder 2. Furthermore, when replenishing each electrode T of the electrode feeder 2 to each electrode replenishment unit 3 connected in series, instead of sequentially supplying electrodes T from the electrode feeder 2 when each electrode replenishment unit 3 needs to supply electrodes T to the downstream side, electrodes T can be supplied from the electrode feeder 2 to the electrode branching passage section 31d of the main frame 31 of each electrode replenishment unit 3 in advance and kept on standby. This allows for efficient supply of electrodes T to the downstream side of each electrode replenishment unit 3, even when many electrode replenishment units 3 are connected in series. Specifically, a sensor can be used to detect whether or not electrodes T are on standby in the electrode branching passage section 31d of each electrode replenishment unit 3. When the control unit of system 1 determines that electrodes T are not on standby in the electrode branching passage section 31d of each electrode replenishment unit 3, it can be controlled to supply electrodes T from the electrode feeder 2 to the electrode replenishment unit 3 where electrodes T are not on standby.

[0129] Furthermore, in the embodiment of the present invention, the first electrode storage device 10A and the second electrode storage device 10B are connected to the first electrode replenishment unit 3A and the second electrode replenishment unit 3B, respectively, meaning that two electrode storage devices are connected to each of the first electrode replenishment unit 3A and the second electrode replenishment unit 3B. However, the invention is not limited to this configuration, and a configuration in which one electrode storage device is connected to each of the first electrode replenishment unit 3A and the second electrode replenishment unit 3B is also possible.

[0130] Furthermore, 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 at a time. However, the invention is not limited to this, and a structure in which multiple electrodes T are stored in the storage passage 11a is also possible.

[0131] Furthermore, in the embodiments of the present invention, the sliding operation of the slide plate 37, the pressing operation of the first pressing block 45 and the second pressing block 33b, and the mechanism for blocking the first passage 41a and the electrode branch passage 31d are performed by the second air cylinder 33 for pressing, the second air cylinder 34 for the gate, the air cylinder 38 for sliding, the first air cylinder 42 for pressing, and the first air cylinder 43 for the gate, respectively. However, these can be replaced with other actuators such as electric cylinders or hydraulic cylinders.

[0132] Furthermore, in the embodiment of the present invention, the first air introduction section 39a, the second electrode replenishment cylinder 6B, and the electrode discharge cylinder 7 are formed on the slide plate 37 in the sliding direction of the slide plate 37 at predetermined intervals from one end, but the invention is not limited to this arrangement, and they may be formed on the slide plate 37 at predetermined intervals along the sliding direction in other arrangements.

[0133] The present invention is suitable for a spot welding electrode replenishment system that automatically replenishes electrodes in an electrode storage device that stores and prepares replacement electrodes for attachment to a spot welding gun.

[0134] 1 Spot welding electrode replenishment system 2 Electrode feeder 3A First electrode replenishment unit 3B Second electrode replenishment unit 4 Feeder unit 5 Electrode supply cylinder 5a Connecting member 6A First electrode replenishment cylinder 6B Second electrode replenishment cylinder 6a First connecting pipe 6b Second air inlet 6c First communication hole 6d Third connecting pipe 6e Fourth connecting pipe 7 Electrode discharge cylinder 7a Second connecting pipe 7b Third air inlet 7c Second communication hole 7d Cover member 9A Stand 9B Electrode removal unit 9a Base plate 9b Support column 9c Control box 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 inlet hole 13d Second air inlet hole 14 Piston 15 Rod member 16 Pressing member 20 Air unit 21 Feeder case 21a Door 21b Operation monitor 21c Emergency button 21d Case opening 21e Case bracket 22 Bowl 23 Electrode guide 30 Cover member 31 Main frame 31A First block 31B Second block 31a First through hole 31b Stepped surface 31c Second through hole 31d Electrode branching passage 31e First electrode outlet 31f Second electrode outlet 31g Electrode inlet 32 ​​Connection switching mechanism 33 Second air cylinder for pressing (second actuator) 33a Second piston rod for pressing (pressing part) 33b Second pressing block 34 34a Second air cylinder for gate 35 Second gate pin 36a Second electrode detection sensor 36a Support frame 36b Bridging frame 37 Slide plate 37a First opening hole 37b Second opening hole 37c Third opening hole 37d Canopy section 38 Slide air cylinder (first actuator) 38a Slide rod 39a First air introduction section 41 Feeder body 41a First passage section 41b Second passage section41c Electrode outlet 41d Air supply opening 42 First air cylinder for pressing 42a First piston rod for pressing 43 First air cylinder for gate 43a First gate pin 44 First electrode detection sensor 45 First pressing block 46 Air introduction section for feeder C1 Rotation axis G Spot welding gun G1 Shank S1 Gap space T Electrode T1 Fitting recess X Electrode replacement device

Claims

1. A spot welding electrode replenishment system comprising a plurality of electrode replenishment units for replenishing electrodes to an electrode storage device that stores and prepares replacement electrodes for mounting on a spot welding gun, wherein each electrode replenishment unit comprises: a main frame provided with an electrode branching passage having an electrode inlet and an electrode outlet; an electrode feeder to which the upstream end of an electrode supply cylinder is connected and which is capable of supplying electrodes one by one with compressed air via the electrode supply cylinder; a connection switching mechanism to which the upstream end of the electrode replenishment cylinder and the upstream end of an electrode discharge cylinder are fixed, respectively, and which switches the connection between the electrode replenishment cylinder and the electrode discharge cylinder to the electrode outlet; and an air unit capable of flowing compressed air downstream inside the electrode replenishment cylinder or the electrode discharge cylinder, wherein the downstream end of the electrode replenishment cylinder is connected to the electrode storage device. A spot welding electrode replenishment system characterized in that the downstream end of the electrode discharge cylinder in each electrode replenishment unit, which is arranged sequentially from upstream to downstream, is connected to the electrode inlet of the next downstream electrode replenishment unit, and the downstream end of the electrode supply cylinder is connected to the electrode inlet of the electrode replenishment unit located at the upstream end.

2. The spot welding electrode replenishment system according to claim 1, wherein the connection switching mechanism comprises a slide plate to which the upstream end of the electrode replenishment cylinder and the upstream end of the electrode discharge cylinder are fixed, and a first actuator that slides the slide plate in the direction in which the electrode replenishment cylinder and the electrode discharge cylinder are arranged side by side, wherein the sliding operation of the slide plate toward one side connects the upstream end of the electrode replenishment cylinder to the electrode outlet, and the sliding operation of the slide plate toward the other side connects the upstream end of the electrode discharge cylinder to the electrode outlet.

3. In the spot welding electrode replenishment system according to claim 2, the electrode storage device is provided with a pair of electrodes for mounting on the spot welding gun in opposite orientations for one electrode replenishment unit, the electrodes introduced into the electrode branch passage from the electrode inlet of the main frame are set in the electrode branch passage with their central axes extending vertically, the electrode outlet comprises a first electrode outlet opening upward and a second electrode outlet opening downward below the first electrode outlet, a pair of electrode replenishment cylinders are provided, one upstream end of which is connected to the first electrode outlet and one downstream end of which is connected from above to one of the electrode storage devices, and the other upstream end of which is connected to the slide plate and the other downstream end of which is connected from above to the other electrode storage device. The spot welding electrode replenishment system is characterized in that the air unit comprises a first air introduction section that can introduce compressed air toward one electrode storage device into the interior of one electrode replenishment cylinder, a second air introduction section that can introduce compressed air toward the other electrode storage device into the interior of the other electrode replenishment cylinder, and a third air introduction section that can introduce compressed air into the interior of the electrode discharge cylinder, wherein the first air introduction section is connected to the slide plate, and the air inlet of the first air introduction section connects to or disconnects from the second electrode outlet by the sliding movement of one or the other side of the slide plate.

4. The spot welding electrode replenishment system according to claim 3, characterized in that the slide plate is connected in order to the first air introduction section, the electrode replenishment cylinder, and the electrode discharge cylinder in a row at predetermined intervals along the sliding direction, and an L-shaped overhang is attached to the upstream end opening of the electrode discharge cylinder from above.

5. A spot welding electrode replenishment system according to claim 3 or 4, wherein the electrode inlet is arranged parallel to the first electrode outlet, opens upward, and is configured to introduce the electrode in a position where its central axis is oriented vertically, and a second actuator having a pressing portion capable of pressing the electrode introduced from the electrode inlet to the space between the first electrode outlet and the second electrode outlet of the electrode branching passage is disposed on the side of the electrode branching passage.

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