Coolant drip prevention system

Abstract

In the coolant drip prevention system (1), one end of the first pipe (4) is connected to a coolant supply pipe (15) on the side of the welding torch (11) with respect to the first stop valve (2). One end of the second pipe (5) is connected to a coolant discharge pipe (16) on the side of the welding torch (11) with respect to the second stop valve (3). One end of the discharge pipe (6) is connected to the coolant discharge pipe (16) on the side away from the welding torch (11) with respect to the second stop valve (3). The pump unit (7) discharges the coolant sucked from the first pipe (4) and the second pipe (5) into the discharge pipe (6).

Description

Technical Field

[0001] This invention relates to a coolant anti-drip system. When the electrode at the tip of the welding torch in a spot welding machine is removed for replacement, the coolant anti-drip system prevents the coolant used for the electrode from dripping from the tip of the welding torch. Background Technology

[0002] The welding torch in a spot welding machine includes an electrode at its tip. The electrode is replaced after a predetermined usage cycle. Replacement involves: closing the shut-off valve on the coolant passage to stop coolant circulation, removing the used electrode from the tip of the welding torch, and attaching a new electrode to the tip of the welding torch. After removing the used electrode, some coolant remaining in the coolant passage may drip through an opening at the tip of the welding torch. This dripping coolant may wet, for example, the operator's body and other equipment.

[0003] In this regard, the coolant anti-drip device described in Patent Document 1 includes, for example, a cylindrical body and a pair of fluid pressure cylinders. The cylindrical body has an opening at one end and a guide hole at the center of the other end. The opening connects to a coolant channel. The pair of fluid pressure cylinders are arranged parallel to each other in a direction perpendicular to the centerline of the cylindrical body. The cylindrical body encloses a partition and a guide rod, the partition dividing the internal space of the cylindrical body into a space closer to the coolant channel and a space closer to the guide hole, the guide rod being slidably fitted through the guide hole. The guide rod has one end connected to the partition and the other end coupled to a piston rod in each fluid pressure cylinder via a coupling bracket. After the electrode is removed from the tip of the welding torch, a shut-off valve on the coolant channel is operated to stop the circulation of coolant circulated by the cooling unit. Then, the piston rods in each fluid pressure cylinder are extended to generate a negative pressure in the space inside the cylindrical body closer to the coolant channel. Coolant is drawn from the coolant channel into the space closer to the coolant channel and does not drip from the opening at the tip of the welding torch.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: WO 2020 / 087959 Summary of the Invention

[0007] Technical issues

[0008] The coolant anti-drip device described in Patent Document 1 cannot draw coolant exceeding a predetermined volume into the space inside the barrel body. When used with, for example, a large welding torch, the coolant anti-drip device may fail to draw all the coolant into the barrel body from the portion of the coolant passage closer to the welding torch than the shut-off valve. In this case, coolant may drip from the tip of the welding torch.

[0009] In response to the above, one or more aspects of the present invention are directed to a coolant anti-drip system for a spot welding machine that reliably prevents coolant from dripping from the tip of the welding torch during electrode changes, regardless of the size or type of equipment.

[0010] Solution to the problem

[0011] In response to the above, the system according to one or more aspects of the present invention allows for electrode replacement when using a pump unit to repeatedly draw coolant from the coolant passage.

[0012] More specifically, a coolant dripping prevention system has the structure described below, which is used to prevent coolant circulating to the electrode through the coolant supply channel and the coolant discharge channel from dripping from the tip of the welding torch when the electrode is removed from the tip of the welding torch in a spot welding machine.

[0013] A coolant anti-drip system according to a first aspect of the invention comprises: a first shut-off valve located at a midpoint along a coolant supply channel to stop supplying coolant to the electrode; a second shut-off valve located at a midpoint along a coolant discharge channel to stop discharging coolant from the electrode; a first tube having a first end connected to a portion of the coolant supply channel closer to the welding torch than the first shut-off valve; a second tube having a first end connected to a portion of the coolant discharge channel closer to the welding torch than the second shut-off valve; a discharge tube having a first end connected to a portion of the coolant discharge channel farther from the welding torch than the second shut-off valve; and a pump unit connected to a second end of each of the first tube, the second tube, and the discharge tube to draw coolant from the first tube and the second tube and discharge the drawn-in coolant into the discharge tube.

[0014] The coolant anti-drip system according to a second aspect of the invention is a coolant anti-drip system according to a first aspect of the invention. The pump unit includes a first connecting pipe, a second connecting pipe, a pair of first check valves, a pair of second check valves, a cylinder body, a baffle plate, a guide rod, a fluid pressure cylinder, a first suction / discharge pipe, and a second suction / discharge pipe. The first connecting pipe connects a second end of a first pipe to a second end of a discharge pipe. The second connecting pipe connects a second end of a second pipe to a second end of a discharge pipe. A pair of first check valves are connected in series along the middle of the first connecting pipe to guide the flow of coolant inside the first connecting pipe from the first pipe toward the discharge pipe. A pair of second check valves are connected in series along the middle of the second connecting pipe to guide the flow of coolant inside the second connecting pipe toward the discharge pipe. The coolant inside the connecting pipe flows from the second pipe toward the discharge pipe; the cylinder body has a first end with a guide hole; a baffle divides the internal space of the cylinder body into a first space along the centerline of the cylinder body in a first direction and a second space along the centerline of the cylinder body in a second direction; a guide rod is slidably fitted through the guide hole and has a first end connected to the baffle; a fluid pressure cylinder is connected to the second end of the guide rod to allow the guide rod to slide; the first suction / discharge pipe has a first end connected to the first space and a second end connected to the portion of the first connecting pipe between a pair of first check valves; the second suction / discharge pipe has a first end connected to the second space and a second end connected to the portion of the second connecting pipe between a pair of second check valves.

[0015] Beneficial effects

[0016] In a first aspect of the invention, electrode replacement involves operating a first shut-off valve and a second shut-off valve to stop the circulation of coolant to the electrode. A pump unit is then activated. Coolant remaining in the portion of the coolant supply channel closer to the welding torch than the first shut-off valve is drawn into the pump unit through a first pipe. Simultaneously, coolant remaining in the portion of the coolant discharge channel closer to the welding torch than the second shut-off valve is drawn into the pump unit through a second pipe. As the pump unit draws in a certain volume of coolant, the drawn-in coolant is returned through a discharge pipe to the portion of the coolant discharge channel further away from the welding torch than the second shut-off valve. The second shut-off valve allows the coolant returned to the coolant discharge channel to be discharged directly without causing the coolant to move towards the welding torch. Thus, the electrode is removed from the tip of the welding torch, while all residual coolant is eliminated from the entire portion of the coolant supply channel closer to the welding torch than the first shut-off valve, and all residual coolant is eliminated from the entire portion of the coolant discharge channel closer to the welding torch than the second shut-off valve, regardless of the type or size of the welding torch. Therefore, coolant dripping from the tip of the welding torch is reliably prevented during electrode changes, regardless of the size or type of equipment.

[0017] In a second aspect of the invention, the fluid pressure cylinder is activated by coolant remaining in the second space. When the guide rod slides in the first direction, a baffle moves to increase the first space. Two first check valves allow coolant in the portion of the coolant supply channel closer to the welding torch than the first shut-off valve to be drawn into the first space through the first pipe, the first connecting pipe, and the first suction / discharge pipe. Simultaneously, two second check valves allow coolant remaining in the second space to be discharged through the second suction / discharge pipe, the second connecting pipe, and the discharge pipe into the portion of the coolant discharge channel farther from the welding torch than the second shut-off valve. The fluid pressure cylinder is activated by coolant remaining in the first space. When the guide rod slides in the second direction, a baffle moves to increase the second space. Two second check valves allow coolant in the portion of the coolant discharge channel closer to the welding torch than the second shut-off valve to be drawn into the second space through the second pipe, the second connecting pipe, and the second suction / discharge pipe. Simultaneously, two first check valves allow coolant remaining in the first space to be discharged through the first suction / discharge pipe, the first connecting pipe, and the discharge pipe into the portion of the coolant discharge channel farther from the welding torch than the second shut-off valve. By moving the baffle back and forth within a single cylinder body in this manner, coolant is alternately drawn in from the coolant supply channel and the coolant discharge channel, and the drawn-in coolant is returned to the coolant discharge channel. Therefore, the coolant anti-drip system is effective and low-cost. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a coolant anti-drip system according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the pump unit in an embodiment of the present invention. Detailed Implementation

[0020] One or more embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The embodiments described below are merely examples.

[0021] Figure 1 A spot welding machine 10 connected to a coolant anti-drip system 1 according to an embodiment of the present invention is shown. The spot welding machine 10 can be used, for example, in an automotive production line to assemble multiple pressed parts (not shown) using spot welding. The spot welding machine 10 includes a welding torch 11, which is generally C-shaped when viewed from the front.

[0022] The welding torch 11 includes a pair of thin handles 11a facing each other at its tip. One handle 11a can move toward and away from the other handle 11a.

[0023] Electrode 12 is detachably attached to the tip of each handle 11a. When viewed from the front, electrode 12 is approximately bell-shaped. In spot welding, the workpiece to be welded (not shown) is placed between the two electrodes 12. In this state, one handle 11a of the welding torch 11 moves toward the other handle 11a to hold the workpiece between the two electrodes 12 and apply pressure to the workpiece between the two electrodes 12. Current is then supplied between the two electrodes 12.

[0024] The welding torch 11 is connected to a cooling unit 13 for cooling the two electrodes 12.

[0025] Cooling unit 13 includes a unit body 14, a coolant supply pipe 15 (coolant supply channel), and a coolant discharge pipe 16 (coolant discharge channel). The unit body 14 includes a pump 14a for circulating coolant and a tank 14b for storing coolant. The coolant supply pipe 15 extends from the unit body 14 to each electrode 12. The coolant discharge pipe 16 extends from each electrode 12 to the unit body 14. Pump 14a is activated to initiate the circulation of coolant through the coolant supply pipe 15 and coolant discharge pipe 16 from the tank 14b to each electrode 12. The circulating coolant cools each electrode 12.

[0026] The coolant anti-drip system 1 includes a first shut-off valve 2 and a second shut-off valve 3. The first shut-off valve 2 is located at the midpoint along the coolant supply pipe 15. The second shut-off valve 3 is located at the midpoint along the coolant discharge pipe 16. The first shut-off valve 2 can stop the supply of coolant to the electrode 12. The second shut-off valve 3 can stop the discharge of coolant from the electrode 12.

[0027] The first pipe 4 has a first end that is connected to a portion of the coolant supply pipe 15 closer to the welding torch 11 than the first shut-off valve 2.

[0028] The second pipe 5 has a first end that is connected to a portion of the coolant discharge pipe 16 closer to the welding torch 11 than the second shut-off valve 3. The discharge pipe 6 has a first end that is connected to a portion of the coolant discharge pipe 16 further away from the welding torch 11 than the second shut-off valve 3.

[0029] Pump unit 7 is connected to the second end of each of the first pipe 4, the second pipe 5, and the discharge pipe 6.

[0030] Pump unit 7 includes a rectangular body housing 70. For example... Figure 2 As shown, the main body housing 70 encloses a first connecting pipe 71 and a second connecting pipe 72 within the main body housing 70. The first connecting pipe 71 connects the second end of the first pipe 4 and the second end of the discharge pipe 6. The second connecting pipe 72 connects the second end of the second pipe 5 and the second end of the discharge pipe 6.

[0031] A pair of first check valves 73 are located at the middle position along the first connecting pipe 71. The first check valves 73 guide the coolant inside the first connecting pipe 71 to flow from the first pipe 4 toward the discharge pipe 6, and the first check valves 73 are arranged in series along the flow direction of the coolant.

[0032] A pair of second check valves 74 are located at the midpoint along the second connecting pipe 72. The second check valves 74 guide the coolant inside the second connecting pipe 72 to flow from the second piping 5 toward the discharge pipe 6, and the second check valves 74 are arranged in series along the flow direction of the coolant.

[0033] The housing 70 also encloses the cylindrical body 75, the partition 76, and the guide rod 77. The cylindrical body 75 has a guide hole 75a at its first end. The partition 76 divides the internal space of the cylindrical body 75 into a first space S1 and a second space S2. The first space S1 is in a first direction along the centerline of the cylindrical body 75. The second space S2 is in a second direction along the centerline of the cylindrical body 75. The guide rod 77 is slidably fitted through the guide hole 75a. The first end of the guide rod 77 is connected to the partition 76.

[0034] The double-acting cylinder 78 is located in the first direction along the centerline of the cylinder body 75. The cylinder 78 is connected to the air supply source via a solenoid valve 79.

[0035] The cylinder 78 includes a piston rod 78a aligned with the centerline of the cylinder body 75 and connected to the second end of a guide rod 77. The piston rod 78a extends and retracts to allow the partition 76 and the guide rod 77 to slide along the centerline of the cylinder body 75.

[0036] A first suction / discharge pipe 7a is routed between the first connecting pipe 71 and the cylinder body 75. The first suction / discharge pipe 7a has a first end and a second end; the first end is connected to the first space S1, and the second end is connected to the portion of the first connecting pipe 71 located between the two first check valves 73. A second suction / discharge pipe 7b is routed between the second connecting pipe 72 and the cylinder body 75. The second suction / discharge pipe 7b has a first end and a second end; the first end is connected to the second space S2, and the second end is connected to the portion of the second connecting pipe 72 located between the two second check valves 74.

[0037] The operation of the coolant anti-drip system 1 according to an embodiment of the present invention will now be described in detail.

[0038] During the replacement of electrode 12 in the welding torch 11 described above, the coolant anti-drip system 1 is activated. A controller (not shown) activates the first shut-off valve 2 and the second shut-off valve 3 to stop the circulation of coolant to electrode 12. The controller then activates the pump unit 7 to actuate cylinder 78. As the piston rod 78a in cylinder 78 extends, the guide rod 77 slides in a first direction. Then, the partition 76 moves together with the guide rod 77 to increase the first space S1 and decrease the second space S2. Two first check valves 73 allow coolant in the portion of the coolant supply pipe 15 closer to the welding torch 11 than the first shut-off valve 2 to be drawn into the first space S1 through the first pipe 4, the first connecting pipe 71, and the first suction / discharge pipe 7a.

[0039] When the piston rod 78a in cylinder 78 retracts, coolant remains in the first space S1, and guide rod 77 slides in the second direction. Then, baffle 76 moves together with guide rod 77 to increase the second space S2 and decrease the first space S1. Two second check valves 74 allow coolant in the portion of coolant discharge pipe 16 closer to the welding torch 11 than the second shut-off valve 3 to be drawn into the second space S2 through the second pipe 5, the second connecting pipe 72, and the second suction / discharge pipe 7b. Simultaneously, two first check valves 73 allow coolant remaining in the first space S1 to be discharged through the first suction / discharge pipe 7a, the first connecting pipe 71, and the discharge pipe 6 into the portion of coolant discharge pipe 16 further away from the welding torch 11 than the second shut-off valve 3.

[0040] When the piston rod 78a in cylinder 78 extends, coolant remains in the second space S2, and guide rod 77 slides in the first direction. Then, partition 76 moves together with guide rod 77 to increase the first space S1 and decrease the second space S2. Two first check valves 73 allow coolant in the portion of coolant supply pipe 15 closer to welding torch 11 than the first shut-off valve 2 to be drawn into the first space S1 through first pipe 4, first connecting pipe 71, and first suction / discharge pipe 7a. Simultaneously, two second check valves 74 allow coolant remaining in the second space S2 to be discharged through the second suction / discharge pipe 7b, second connecting pipe 72, and discharge pipe 6 into the portion of coolant discharge pipe 16 further away from welding torch 11 than the second shut-off valve 3.

[0041] In this way, pump unit 7 draws in coolant from first pipe 4 and second pipe 5 and discharges the drawn-in coolant into discharge pipe 6.

[0042] As described above, the coolant anti-drip system 1 according to an embodiment of the present invention has the following structure. Coolant remaining in the portion of the coolant supply pipe 15 closer to the welding torch 11 than the first shut-off valve 2 is drawn into the pump unit 7 through the first pipe 4. Simultaneously, coolant remaining in the portion of the coolant discharge pipe 16 closer to the welding torch 11 than the second shut-off valve 3 is drawn into the pump unit 7 through the second pipe 5. As the pump unit 7 draws in a certain volume of coolant, the drawn-in coolant returns through the discharge pipe 6 to the portion of the coolant discharge pipe 16 further away from the welding torch 11 than the second shut-off valve 3. The second shut-off valve 3 allows the coolant returning to the coolant discharge pipe 16 to be directly discharged instead of moving towards the welding torch 11. Therefore, electrode 12 is removed from the tip of welding torch 11, simultaneously eliminating all residual coolant from the entire portion of coolant supply pipe 15 closer to welding torch 11 than the first shut-off valve 2, and from the entire portion of coolant discharge pipe 16 closer to welding torch 11 than the second shut-off valve 3, regardless of the type or size of welding torch 11. Thus, during electrode 12 replacement, coolant dripping from the tip of welding torch 11 is reliably prevented, regardless of the size or type of equipment. Furthermore, the back-and-forth movement of baffle 76 within a single cylinder body 75 in this manner allows for the alternating intake of coolant from coolant supply pipe 15 and coolant from coolant discharge pipe 16, and also allows the intake coolant to return to coolant discharge pipe 16. Therefore, the coolant anti-drip system 1 is effective and low-cost.

[0043] In the above embodiments of the invention, the pump unit 7 draws in coolant from the coolant supply pipe 15 and the coolant discharge pipe 16 by moving the baffle 76 back and forth inside the cylinder body 75. However, any other type of pump unit can be used to draw in coolant from the first pipe 4 and the second pipe 5 and discharge the drawn-in coolant into the discharge pipe 6.

[0044] In the above embodiments of the present invention, the fluid pressure cylinder in the pump unit 7 is a pneumatic cylinder 78. However, other types of fluid pressure cylinders can be used.

[0045] Industrial applicability

[0046] One or more embodiments of the present invention can be implemented as a coolant anti-drip system to be connected to a spot welding machine. When the electrode at the tip of the welding torch in the spot welding machine is removed for replacement, the coolant anti-drip system prevents coolant used for the electrode from dripping from the tip of the welding torch.

[0047] List of reference numerals

[0048] 1. Coolant anti-drip system

[0049] 2 First shut-off valve

[0050] 3 Second shut-off valve

[0051] 4 First tube

[0052] 5 Second tube

[0053] 6 Discharge pipe

[0054] 7 pump units

[0055] 7a First suction and discharge pipe

[0056] 7b Second suction and discharge pipe

[0057] 10-point welding machine

[0058] 11 welding torch

[0059] 11a handle

[0060] 12 electrodes

[0061] 15. Coolant supply pipe (coolant supply channel)

[0062] 16. Coolant drain pipe (coolant drain channel)

[0063] 71 First connecting pipe

[0064] 72 Second connecting pipe

[0065] 73 First Check Valve

[0066] 74 Second check valve

[0067] 75 barrel body

[0068] 75a guide hole

[0069] 76 partitions

[0070] 77 guide rod

[0071] 78 cylinder (fluid pressure cylinder)

[0072] S1 First Space

[0073] S2 Second Space

Claims

1. A coolant anti-drip system for preventing coolant circulating in the electrode through a coolant supply channel and a coolant discharge channel from dripping from the tip of a welding torch in a spot welding machine when the electrode is removed from the tip of the torch, the coolant anti-drip system comprising: A first shut-off valve is located at the midpoint along the coolant supply channel to stop the supply of coolant to the electrode; A second shut-off valve is located at the midpoint along the coolant discharge channel to stop the discharge of coolant from the electrode; A first tube, the first tube having a first end, the first end being connected to a portion of the coolant supply channel closer to the welding torch than the first shut-off valve; The second tube has a first end, which is connected to the portion of the coolant discharge channel that is closer to the welding torch than the second shut-off valve. A discharge pipe having a first end connected to a portion of the coolant discharge passage that is further away from the welding torch than the second shut-off valve; as well as A pump unit, connected to a second end of each of the first pipe, the second pipe, and the discharge pipe, for drawing in coolant from the first pipe and the second pipe and discharging the drawn-in coolant into the discharge pipe, wherein... The pump unit includes a first connecting pipe, a second connecting pipe, a pair of first check valves, a pair of second check valves, a cylinder body, a baffle, a guide rod, a fluid pressure cylinder, a first suction pipe, and a second suction pipe; the first connecting pipe connects the second end of the first pipe and the second end of the discharge pipe; the second connecting pipe connects the second end of the second pipe and the second end of the discharge pipe; the pair of first check valves are connected in series along the middle of the first connecting pipe to guide the flow of coolant inside the first connecting pipe from the first pipe toward the discharge pipe; The pair of second check valves are connected in series at the midpoint along the second connecting pipe to guide the flow of coolant inside the second connecting pipe from the second pipe toward the discharge pipe; the cylinder body has a first end with a guide hole; the baffle divides the internal space of the cylinder body into a first space along the centerline of the cylinder body in a first direction and a second space along the centerline of the cylinder body in a second direction; the guide rod is slidably fitted through the guide hole and has a first end connected to the baffle; the fluid pressure cylinder is connected to the second end of the guide rod to allow the guide rod to slide; the first suction / discharge pipe has a first end connected to the first space and a second end connected to the portion of the first connecting pipe between the pair of first check valves; the second suction / discharge pipe has a first end connected to the second space and a second end connected to the portion of the second connecting pipe between the pair of second check valves, and The fluid pressure cylinder is a double-acting cylinder and is configured to increase the first space and decrease the second space by extending the piston rod to move the partition together with the guide rod sliding in the first direction, and to decrease the first space and increase the second space by retracting the piston rod to move the partition together with the guide rod sliding in the second direction.

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