Magazine for spot welding chip

A magazine for spot welding electrodes that stores mini chips and can feed the mini chips one by one. A mini chip storage portion and a cap chip storage portion slidably aligning and storing a plurality of mini chips and a plurality of cap chips are formed such that the mini chip storage portion and cap chip storage portion communicate with each other at one of their ends, where they open to the outside to serve as a supply port. When an arm is inserted into the supply port, a cap chip is mounted to the arm, as well as the cap chip presses the mini chip so that the mini chip is also mounted to the chip base. When the mounting operation is complete, a push-out member pushes the mini chips and cap chips so that the mini chips and cap chips are automatically fed to the supply port.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a magazine for storing mini chips that are to be fitted to distal ends of chip bases of a spot welder.

2. Description of Related Art

Conventionally, spot welding has been widely used as one means for welding metal workpieces, wherein, with the metal workpieces being pressed together, electric current is applied, so as to melt and fuse the metal with the resistance heat. An automated welding line for spot welding body parts of cars is made up of a robot equipped with a welding gun, and a jig for securing and moving a workpiece to be welded. Alternatively, an automated welding line is made up of a stationary welding gun, and a robot that holds a workpiece to be welded and moves this workpiece to be welded toward the stationary welding gun.

The welding gun, as shown inFIG. 15, has opposing arms190and191, with cap chips195fitted to the mounting portions190aand191aformed at the distal ends of the arms. In a process in which welding is performed using a welding gun mounted on a robot, the robot is operated to move the opposing arms190and191to a weld spot252of workpieces to be welded250and251, and while the cap chips195are pressed against the workpieces to be welded250and251, electric current is applied so as to weld the workpieces250and251together. Alternatively, in a process in which welding is performed using a stationary welding gun, the workpieces to be welded250and251are moved by the robot to the position between the opposing arms190and191, and while the cap chips195are pressed against the weld spot252of the workpieces to be welded250and251, electric current is applied so as to weld the workpieces250and251together.

In a welding gun such as the one shown inFIG. 15, when there is present a member255near the workpiece to be welded250, the arm190and cap chip195cannot fit in between the workpiece to be welded250and the member255due to the large dimension α from the base of the mounting portion190ato the distal end of the cap chip195, so the workpieces250and251cannot be welded together. Therefore, for such welding spots, a chip base301such as the one shown inFIG. 16is commonly used instead of the arm190.

A mini chip302is mounted to the distal end of the chip base301.FIG. 17shows a detailed view of the chip base301, andFIG. 18shows a detailed view of the mini chip. As shown inFIG. 17, the chip base301has a plate-like shape, and the mini chip302is mounted in a mounting hole301aformed at the distal end of the chip base301such as to extend therethrough. Therefore the thickness dimension β from the distal end of the chip base301to an abutment portion302aof the mini chip302is small, so that even in a narrow space where there is present a member255close to the workpiece to be welded250, the mini chip302can be moved to the weld spot252and the workpieces250and251can be welded together.

Performing the spot welding more than a predetermined number of times causes the distal end shape of the abutment portion302aof the mini chip302or the cap chip195to suffer deformation and wear, making it harder to secure required welding quality. Therefore, when a certain period of processing time or a certain number of welding points is exceeded, the mini chip302or cap chip195need to be removed and replaced with new ones or those that have undergone a grinding treatment.

Conventionally, an operator would go inside the automated welding line that had been paused, and remove the cap chip195by inserting a tool for removing electrode chips such as the one shown in Patent Document 1 to the distal end of the arm191, or remove the mini chip302by hitting its mounting portion302bthrough the mounting hole301aof the chip base301. However, it was very dangerous for the operator to go inside the automated welding line, as it meant going inside a movable range of the robot arm. Also, for the operator to go inside the automated welding line, it was necessary to stop the automated welding line, which led to the problem that production efficiency was deteriorated. Further, in recent years, many of the materials to be welded are provided with rust proof treatment or the like using chemicals, because of which mini chips302and cap chips195tend to wear more quickly and need to be replaced more frequently. However, stopping the automated welding line each time to replace the mini chip302or cap chip195would lead to the problem of production efficiency being largely deteriorated.

Accordingly, a welder cap chip removing apparatus has been proposed as shown in Patent Document 2. This welder cap chip removing apparatus is made up of a fixed claw to be inserted into the distal end of the arm191, a movable claw rotatably attached to a base end of this fixed claw such as to contact and separate from the fixed claw, and a rotating Mechanism that applies a rotating force to the movable claw. To remove the cap chip195, the robot arm is moved to insert the distal end of the arm191in between the fixed claw and movable claw, and when the movable claw is separated from the fixed claw, the cap chip195is removed from the arm191.

When using this welder cap chip removing apparatus shown in Patent Document 2, a magazine rack for a chip changer such as the one shown in Patent Document 3 is used for storing replacement cap chips. This magazine rack for a chip changer shown in Patent Document 3 is formed such that a plurality of cap chips195are stored inside a long columnar rack body and fed one by one to a supply port. With this magazine rack for a chip changer installed near the robot arm, a cap chip195can be automatically mounted to the arm191by moving the welding gun using the robot arm to insert the mounting portion191aof the arm191, from which the cap chip195has been removed, into the supply port of the magazine rack for a chip changer. By thus using the welder cap chip removing apparatus shown in Patent Document 2 and the magazine rack for a chip changer shown in Patent Document 3, automatic mounting and dismounting of cap chips195to and from the arm191of the welding gun in an automated welding line would be possible.

However, while the welder cap chip removing apparatus shown in Patent Document 2 can remove cap chips195, it cannot remove mini chips302, and therefore if there is even one process step in which mini chips302are used in the automated welding line, the automated welding line would still be stopped, as had been conventionally done, for the operator to go inside the automated welding line to remove the mini chip302from the chip base301and mount a new mini chip302to the chip base301. Accordingly, the problem of the operator being exposed to danger, or the problem that the production efficiency of the automated welding line was largely deteriorated, would remain unsolved. Therefore, development of a magazine for spot welding chip for storing mini chips as well as a mini chip removing apparatus has been desired.

Patent Document 1: Japanese Published Unexamined Patent Application No. H11-123565

Patent Document 3: Japanese Published Unexamined Patent Application No. 2006-68787

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

An object of the present invention is to solve the above-described problems and to provide a magazine for spot welding electrodes that stores a plurality of mini chips and that can feed the mini chips one by one.

The invention devised to solve the conventionally encountered problems discussed above is characterized by comprising a magazine block formed with a mini chip storage portion slidably aligning and storing a plurality of mini chips therein along a front to back direction, a front end of this mini chip storage portion serving as an externally opened mini chip supply port; and

a push-out mechanism that pushes out the mini chips stored inside the mini chip storage portion toward a side of the mini chip supply port to feed the mini chips to the mini chip supply port one by one.

The invention as set forth above is characterized in that, the push-out mechanism is formed such that:

a mini chip push-out member is slidably disposed inside the mini chip storage portion;

a pulley is disposed in a front part of the magazine block;

a spiral spring is disposed in a rear part of the magazine block;

a distal end of the spiral spring and the mini chip push-out member are coupled by a wire, with an intermediate part of the wire being wound around the pulley; and

the mini chip push-out member is always pulled toward the side of the mini chip supply port by a biasing force of the spiral spring.

The invention as set forth above is characterized in that, the magazine block is formed with a cap chip storage portion in parallel with the mini chip storage portion, the cap chip storage portion slidably aligning and storing a plurality of cap chips therein,

a front end of the cap chip storage portion serving as an externally opened cap chip supply port; and

a push-out mechanism is provided that pushes out the cap chips stored inside the cap chip storage portion toward a side of the cap chip supply port to feed the cap chips to the cap chip supply port one by one.

The invention as set forth above is characterized in that, the push-out mechanism is formed such that:

a cap chip push-out member is slidably disposed inside the cap chip storage portion;

a pulley is disposed in a front part of the magazine block;

a spiral spring is disposed in a rear part of the magazine block;

a distal end of the spiral spring and the cap chip push-out member are coupled by a wire, with an intermediate part of the wire being wound around the pulley; and

the cap chip push-out member is always pulled toward the side of the cap chip supply port by a biasing force of the spiral spring.

The invention as set forth above is characterized in that, the mini chip supply port and the cap chip supply port communicate with each other.

The invention as set forth above is characterized in that, a magazine body is formed to slide in a widthwise direction of the magazine body.

The invention as set forth above is characterized in that, a biasing means is provided for biasing the magazine body toward the side of the cap chip supply port.

The invention as set forth above is characterized in that, the magazine body is mounted on a slide member that slides in a given direction;

a through hole is formed in the slide member;

a shaft is passed through the through hole so as to slide the slide member in the widthwise direction of the magazine body; and

a coil spring is attached to the shaft exposed from the through hole on the side of the mini chip supply port so as to bias the slide member toward the side of the cap chip supply port.

The invention as set forth above is characterized in that, a pressing mechanism having a pressing pin that slides in the widthwise direction of the magazine body and a coil spring that biases the pressing pin toward the side of the cap chip supply port is mounted to the magazine body such that a distal end of the pressing pin protrudes from an opening plane of the cap chip supply port with respect to the widthwise direction of the magazine body; and

the biasing means that biases the magazine body toward the side of the cap chip supply port has a smaller biasing force than that of the coil spring.

The invention as set forth above is characterized in that, a coil spring is mounted to the magazine body such that a distal end of the coil spring protrudes from an opening plane of the cap chip supply port with respect to the widthwise direction of the magazine body; and

the biasing means that biases the magazine body toward the side of the cap chip supply port has a smaller biasing force than that of the coil spring.

The invention as set forth above is characterized by comprising a magazine block formed with a mini chip storage portion slidably aligning and storing a plurality of mini chips therein along a front to back direction, a front end of this mini chip storage portion serving as an externally opened mini chip supply port; and

a push-out mechanism that pushes out the mini chips stored inside the mini chip storage portion toward a side of the mini chip supply port to feed the mini chips to the mini chip supply port one by one.

Therefore, a plurality of mini chips are stored and the mini chips can be fed one by one, so that, in an automated welding line, a mini chip can be automatically mounted to a chip base by moving a welding gun, whereby, as it is no longer necessary to stop the automated welding line for an operator to go inside the automated welding line and mount the mini chip to the chip base, the problem of the operator being exposed to danger, or the problem that production efficiency of the automated welding line is largely deteriorated, can be solved.

The invention as set forth above is characterized in that, the push-out mechanism is formed such that a mini chip push-out member is slidably disposed inside the mini chip storage portion, and the mini chip push-out member is pulled by a spiral spring.

Therefore, when there are a fewer number of mini chips inside the mini chip storage portion, the mini chips are pushed against an end portion of the mini chip storage portion by the mini chip push-out member with an almost constant force, since the biasing force of the spiral spring is almost constant, and therefore the mini chips can be prevented from falling off from the mini chip supply port.

The invention as set forth above is characterized in that, the push-out mechanism is formed such that:

a pulley is disposed in a front part of the magazine block;

a spiral spring is disposed in a rear part of the magazine block;

a distal end of the spiral spring and the mini chip push-out member are coupled by a wire, with an intermediate part of the wire being wound around the pulley; and

the mini chip push-out member is always pulled toward the side of the mini chip supply port by a biasing force of the spiral spring.

Therefore, by inverting the biasing direction of the spiral spring by means of the pulley, it has become possible to provide the spiral spring on the opposite side of the mini chip supply port of the magazine body, so that the area around the mini chip supply port is not bulky and the chip base of the welding gun can be prevented from interfering with the magazine body.

The invention as set forth above is characterized in that, the magazine block is formed with a cap chip storage portion in parallel with the mini chip storage portion, the cap chip storage portion slidably aligning and storing a plurality of cap chips therein, a front end of the cap chip storage portion serving as an externally opened cap chip supply port; and

a push-out mechanism is provided that pushes out the cap chips stored inside the cap chip storage portion toward a side of the cap chip supply port to feed the cap chips to the cap chip supply port one by one.

Therefore, not only the mini chips, but also cap chips can be stored and supplied one by one.

The invention as set forth above is characterized in that, the push-out mechanism is formed such that a cap chip push-out member is slidably disposed inside the cap chip storage portion, and the cap chip push-out member is pulled by a spiral spring.

Therefore, when there are a fewer number of cap chips inside the cap chip storage portion, the cap chips are pushed against an end portion of the cap chip storage portion by the cap chip push-out member with an almost constant force, since the biasing force of the spiral spring is almost constant, and therefore the cap chips can be prevented from falling off from the cap chip supply port.

The invention as set forth above is characterized in that, the push-out mechanism is formed such that:

a pulley is disposed in a front part of the magazine block;

a spiral spring is disposed in a rear part of the magazine block;

a distal end of the spiral spring and the cap chip push-out member are coupled by a wire, with an intermediate part of the wire being wound around the pulley; and

the cap chip push-out member is always pulled toward the side of the cap chip supply port by a biasing force of the spiral spring.

Therefore, by inverting the biasing direction of the spiral spring by means of the pulley, it has become possible to provide the spiral spring on the opposite side of the cap chip supply port of the magazine body, so that the area around the cap chip supply port is not bulky and the arm of the welding gun can be prevented from interfering with the magazine body.

The invention as set forth above is characterized in that, the mini chip supply port and the cap chip supply port communicate with each other.

Therefore, when a mounting portion of the arm is inserted into the cap chip supply port and the cap chip is mounted to the mounting portion of the arm, at the same time, a mini chip is pushed out of the mini chip supply port by the cap chip and mounted to the chip base, so that the mounting operation of the cap chip and mini chip can be carried out in a short time.

The invention as set forth above is characterized in that, a magazine body is formed to slide in a widthwise direction of the magazine body.

Therefore, when the mounting portion of the arm is inserted into the cap chip supply port to mount the cap chip to the mounting portion of the arm, the magazine body slides toward the chip base side, thereby bringing about a state in which the mini chip supply port communicates with the mounting hole of the chip base, so that the mini chip does not fall off from the mini chip supply port and the mounting portion of the mini chip can reliably be made to enter into the mounting hole of the chip base to reliably mount the mini chip to the chip base.

The invention as set forth above is characterized in that, a biasing means is provided for biasing the magazine body toward the side of the cap chip supply port.

Therefore, when mounting of the cap chip and mini chip is complete and the arm is opened from the chip base, the biasing force of the biasing means causes the magazine body to move to its initial position, and concurrently the mini chip mounted to the chip base is escaped from the mini chip supply port, so that the mini chip mounted to the chip base can be reliably escaped from the mini chip supply port.

The invention as set forth above is characterized in that, the magazine body is mounted on a slide member that slides in a given direction;

a through hole is formed in the slide member;

a shaft is passed through the through hole so as to slide the slide member in the widthwise direction of the magazine body; and

a coil spring is attached to the shaft exposed from the through hole on the side of the mini chip supply port so as to bias the slide member toward the side of the cap chip supply port.

Therefore, the structure that allows for smooth sliding of the slide member and stable biasing of the slide member toward the cap chip supply port side can be realized.

The invention as set forth above is characterized in that, a pressing mechanism having a pressing pin that slides in the widthwise direction of the magazine body and a coil spring that biases the pressing pin toward the side of the cap chip supply port is mounted to the magazine body such that a distal end of the pressing pin protrudes from an opening plane of the cap chip supply port with respect to the widthwise direction of the magazine body; and

the biasing means that biases the magazine body toward the side of the cap chip supply port has a smaller biasing force than that of the coil spring.

Therefore, when the mounting portion of the arm is inserted into the cap chip supply port to mount the cap chip to the mounting portion of the arm, the magazine body can be reliably slid toward the chip base side by the arm pressing the pressing pin, whereby the mini chip supply port and the mounting hole of the chip base can be reliably communicated with each other, so as to reliably mount the mini chip to the chip base.

The invention as set forth above is characterized in that, a coil spring is mounted to the magazine body such that a distal end of the coil spring protrudes from an opening plane of the cap chip supply port with respect to the widthwise direction of the magazine body; and

the biasing means that biases the magazine body toward the side of the cap chip supply port has a smaller biasing force than that of the coil spring.

Therefore, when the mounting portion of the arm is inserted into the cap chip supply port to mount the cap chip to the mounting portion of the arm, the magazine body can be reliably slid toward the chip base side by the arm pressing the pressing pin, whereby the mini chip supply port and the mounting hole of the chip base can be reliably communicated with each other, so as to reliably mount the mini chip to the chip base.

DESCRIPTION OF REFERENCE NUMERALS

3hbase end face

11amini chip storage portion

11bmini chip supply port

11dcap chip storage portion

11ecap chip supply port

11ibobbin storage portion

50magazine for spot welding chip

250workpiece to be welded

251workpiece to be welded

301bcooling water passage

DETAILED DESCRIPTION OF THE INVENTION

(Description of the Mini Chip and Chip Base)

Mini chips302stored in the mini chip magazine50of the present invention will be described. As shown in FIG.18(1), the mini chip302is made up of a columnar abutment portion302aand a mounting portion302bformed below the abutment portion302a. The mounting portion302bhas a smaller outside diameter than the abutment portion302aand is formed in a tapered shape so that the outside diameter decreases toward the lower end. The mini chip302may have a shape wherein both sides of the abutment portion302aare cut off, as shown in FIG.18(2).

The chip base301to which the mini chip302is mounted will be described. As shown inFIG. 17, the chip base301has a plate-like shape. The distal end of the chip base301is thinner as compared to other parts. At the distal end of the chip base301, a mounting hole301ais formed such as to extend through the plate. The mounting hole301ais formed in a tapered shape wherein the inside diameter increases toward the side of the abutment portion302aof the mini chip302. The taper angle of the mounting hole301ais the same angle as that of the mounting portion302b. The mounting portion302bof the mini chip302is inserted into the mounting hole301aof the chip base301such as to fit therein so as to mount the mini chip302to the chip base301. The chip base301is formed with a cooling water passage301bthat extends from the base end side to as far as near the mounting hole301a. Cooling water circulating through the cooling water passage301bcools the distal end of the chip base301, thereby cooling the mini chip302.

(Structure of the Magazine for Spot Welding Chips)

Hereinafter preferred embodiments of the present invention will be described with reference to the drawings.FIG. 1is a top view of a magazine50for spot welding chips of the present invention,FIG. 2is a side view ofFIG. 1, andFIG. 3is a cross sectional view taken along A-A ofFIG. 1. The magazine50for spot welding chips of the present invention is made up of a magazine body10, a pressing mechanism3, and a base30.

FIG. 4shows a top view of the magazine body10,FIG. 5shows a cross sectional view taken along B-B ofFIG. 4, andFIG. 6shows a cross sectional view taken along C-C ofFIG. 4.FIG. 7shows a cross sectional view taken along D-D ofFIG. 4. The magazine body10is mainly made up of magazine block11, mini chip push-out member12, spiral spring14, pulley15, bobbin19, cap chip push-out member22, spiral spring24, pulley25, bobbin29, cover plate2, and bottom plate13.FIG. 4shows a state in which the cover plate2has been removed so that the inner structure is visible.

The magazine block11is in the form of an elongated block. The magazine block11is formed with a mini chip storage portion11aoriented along a lengthwise direction (front to back direction). In this embodiment, the mini chip storage portion11ais formed in a recessed shape along a straight line in the magazine block11, having an externally opened shape. The front end of the mini chip storage portion11aserves as a mini chip supply port11b. As shown inFIG. 2, the mini chip supply port11bopens to the outside (in the widthwise direction of the magazine body10). The width of the mini chip storage portion11ais slightly larger than the height of the mini chips302. The mini chips302are slidably aligned and stored inside the mini chip storage portion11asuch that the mini chips302are on their sides so that their mounting portions302bare oriented to the side of the supply port11b.

As shown inFIG. 7, a bottom portion of the mini chip storage portion11aon the side of the mini chip supply port11bis protruded upward, thereby forming a support portion11j. With this structure, the support portion11jabuts on the mounting portions302bof the mini chips302and supports the mounting portions302b, so that the mini chips302stored in the mini chip storage portion11ado not tilt. The support portion11jis not formed near the mini chip supply port11bso as to allow the mini chips302to get out from the mini chip supply port11b. Although the support portion11jis not formed near the mini chip supply port11b, as will be described later, the mini chips302are pressed against an end portion11nof the mini chip storage portion11aby the mini chip push-out member12, so that the mini chips302do not tilt and stay held.

The magazine block11is formed with a cap chip storage portion11din parallel with the mini chip storage portion11a. In this embodiment, the cap chip storage portion11dis formed in a recessed shape along a straight line in the magazine block11, having an externally opened shape. The front end of the cap chip storage portion11dserves as a cap chip supply port11e. The cap chip supply port11eopens to the outside (in the widthwise direction of the magazine body10). The width of the cap chip storage portion11dis slightly larger than the height of the cap chips195. The cap chips195are aligned and stored inside the cap chip storage portion11dsuch that the cap chips195are on their sides so that their mounting recesses195aare oriented to the side of the cap chip supply port11e.

As shown inFIG. 4, there is a partition wall11kbetween the mini chip storage portion11aand cap chip storage portion11d. This partition wall11kis formed as far as to a point before the mini chip supply port11band cap chip supply port11e. In other words, there is no partition wall11kat the positions of the mini chip supply port11band cap chip supply port11eso that the mini chip supply port11band cap chip supply port11ecommunicate with each other.

As shown inFIGS. 5 and 6, below the mini chip storage portion11aand cap chip storage portion11dof the magazine block11is formed a hollow portion11f. In this embodiment, the hollow portion11fis open on the underside.

As shown inFIG. 4, at the bottom portion of the mini chip storage portion11a, a guide groove11gthat communicates with the hollow portion11fis formed along the lengthwise direction of the mini chip storage portion11a. Similarly, at the bottom portion of the cap chip storage portion11d, a guide groove11hthat communicates with the hollow portion11fis formed along the lengthwise direction of the cap chip storage portion11d.

At one end of the hollow portion11fon the opposite side of the mini chip supply port11b(cap chip supply port11e) is formed a bobbin storage portion11i.

As shown inFIGS. 5 to 7, the bottom plate13that closes the hollow portion11fis attached to the underside of the magazine block11.

The mini chip push-out member12is slidably disposed inside the mini chip storage portion11a. The mini chip push-out member12is in the shape of a block, and as shown inFIG. 7, the cross-sectional shape of the mini chip push-out member12conforms to that of the mini chip storage portion11a.

The cap chip push-out member22is slidably disposed inside the cap chip storage portion11d. The cap chip push-out member22is in the shape of a block. As shown inFIG. 7, the cross-sectional shape of the cap chip push-out member22conforms to that of the cap chip storage portion11d.

The cover plate2is disposed on the upper side of the magazine block11to close the mini chip storage portion11aand cap chip storage portion11d. This cover plate2prevents foreign matter from entering the mini chip storage portion11aand cap chip storage portion11d. The cover plate2is formed with a guide groove2athat runs along the mini chip storage portion11aand communicates with the mini chip storage portion11a. The cover plate2is also formed with a guide groove2bthat runs along the cap chip storage portion11dand communicates with the cap chip storage portion11d.

A guide pin17protrudes from the upper face of the mini chip push-out member12. As shown inFIGS. 1 and 2, the guide pin17extends through the guide groove2aof the cover plate2and protrudes from the cover plate2. A guide pin18protrudes from the lower face of the mini chip push-out member12. The guide pin18extends through the guide groove11gand protrudes into the hollow portion11f. This structure allows the guide pins17and18to slidably engage with the guide grooves2aand11g, respectively, so that the mini chip push-out member12can smoothly slide between both ends of the mini chip storage portion11awithout wobbling.

Similarly, a guide pin27protrudes from the upper face of the cap chip push-out member22. As shown inFIG. 1, the guide pin27extends through the guide groove2bof the cover plate2and protrudes from the cover plate2. A guide pin28protrudes from the lower face of the cap chip push-out member22. The guide pin28extends through the guide groove11hand protrudes into the hollow portion11i. This structure allows the guide pins27and28to slidably engage with the guide grooves2band11h, respectively, so that the cap chip push-out member22can smoothly slide between both ends of the cap chip storage portion11dwithout wobbling.

In a front part of the magazine block11is disposed the pulley15. In this embodiment, the pulley15is disposed inside the hollow portion11ibelow the mini chip supply port11b. The pulley15is substantially columnar and formed with a reel portion15athat is in a recessed shape and extends all around the entire circumference. The pulley15is rotatably attached with a shaft to the magazine block11.

Similarly, in the front part of the magazine block11is disposed the pulley25. In this embodiment, the pulley25is disposed inside the hollow portion11fbelow the cap chip supply port11e. The pulley25is substantially columnar and formed with a reel portion25athat is in a recessed shape and extends all around the entire circumference. The pulley25is rotatably attached with a shaft to the magazine block11.

The bobbins19and29are disposed side by side inside the bobbin storage portion11i. In other words, the bobbins19and29are disposed at a position on the opposite side of the mini chip supply port11b(cap chip supply port11e) of the magazine block11, i.e., in the rear part of the magazine block11. The bobbins19and29are in a reel shape and rotatably attached with a shaft to the magazine block11. The spiral springs14and24are respectively wound around the bobbins19and29. The spiral springs14and24are formed of a resilient metal plate material in a spiral shape. The spiral springs14and24are resilient so that even if the distal ends of the spiral springs14and24are pulled, they wind back up in the coil form and restore to their original shapes.

The distal end of the spiral spring14is coupled to one end of the wire16by means of a fastening member7. An intermediate part of the wire16is wound around the pulley15, and the other end of the wire16is coupled to the mini chip push-out member12. In this embodiment, the other end of the wire16is coupled to the protruding end of the guide pin18. With this structure, the spiral spring14pulls the mini chip push-out member12toward the side of the mini chip supply port11bthrough the wire16.

Similarly, the distal end of the spiral spring24is coupled to one end of the wire26by means of a fastening member8. An intermediate part of the wire26is wound around the pulley25, and the other end of the wire26is coupled to the cap chip push-out member22. In this embodiment, the other end of the wire26is coupled to the protruding end of the guide pin28. With this structure, the spiral spring24pulls the cap chip push-out member22toward the side of the cap chip supply port11ethrough the wire26.

As shown inFIGS. 1 and 2, the pressing mechanism3is disposed above the cap chip supply port11eof the magazine body10. In this embodiment, the pressing mechanism3is attached on the cover plate2. As shown inFIGS. 1 and 3, the pressing mechanism3is made up of a main body3a, coil spring3b, pressing pin3c, and cover member3d. The main body3ahas a box-like shape open on the side of the cap chip supply port11e.

The cover member3dis tubular and has a bottom. The cover member3dis attached to the main body3asuch as to close the opening of the main body3a. The cover member3dis formed with an insert hole3ethat opens toward the side of the cap chip supply port11e.

The pressing pin3cis made up of an abutment portion3fand a flange portion3g. The abutment portion3fis columnar. The flange portion3gis in a flange shape and integral with the base end of the abutment portion3f. As shown inFIG. 3, the pressing pin3cis slidably attached to the cover member3dsuch that, with the flange portion3gon the inner side of the cover member3d, the abutment portion3fis passed through the insert hole3ein the cover member3dto protrude out from the insert hole3e. The pressing pin3cslides in the widthwise direction of the magazine body10.

The coil spring3bis accommodated inside the space formed by the main body3aand cover member3d. The coil spring3babuts on the flange portion3gof the pressing pin3cand always biases the pressing pin3ctoward the side of the cap chip supply port11e. The distal end of the abutment portion3fof the pressing pin3cprotrudes from an opening plane11qof the cap chip supply port11ewith respect to the widthwise direction of the magazine body10.

As shown inFIG. 3, the opening plane11mof the mini chip supply port11band the end face2cof the cover plate2on the side of the mini chip supply port11bare coplanar with respect to the widthwise direction of the magazine body10. In this embodiment, the base end face3hof the main body3ais also coplanar with the end face2cof the cover plate2with respect to the widthwise direction of the magazine body10.

Next, the base30will be described. The base30is made up of a slide member31, shaft32, coil spring33, side plate34, side plate35, and base plate36. The magazine body10is mounted on the slide member31. The slide member31has a plate-like shape in the illustrated embodiment. The slide member31is formed with a plurality of through holes31aextending through the magazine body10in its widthwise direction. In this embodiment, through holes31aare formed in the slide member31at two locations in a front to back direction of the magazine body10.

Shafts32are passed through the through holes31aof the slide member31. The shafts32are supported at both ends respectively by the side plate34and side plate35. The cap chip supply port11eis on the side of the side plate34, while the mini chip supply port11bis on the side of the side plate35. Side plates34and35are mounted on the base plate36. With this structure, the slide member31is slidable relative to the base plate36. That is, the magazine body10is slidable in the widthwise direction of the magazine body10. Instead of using the shafts32, the slide member31may be mounted on rails to configure the slide member31slidable in the widthwise direction of the magazine body10.

The coil spring33is attached to the shaft32exposing from the through hole31aon the side of the mini chip supply port11b. In other words, the coil spring33is attached on an outer circumferential surface of the shaft32in between the slide member31and side plate35. Therefore, the slide member31is always biased toward the side of the cap chip supply port11e. With this structure, the magazine body10is always biased toward the side of the side plate34(cap chip supply port11eside). The coil spring33is attached at both ends to the slide member31and side plate35, respectively. Therefore, when it is attempted to move the slide member31toward the side of the side plate34beyond the natural length of the coil spring33, the slide member31is pulled back by the coil spring33toward the side plate35. The spring constant of the coil spring33is smaller than that of the coil spring3b. In this embodiment, the spring constant of the coil spring33is about 2.5 N/mm, while the spring constant of the coil spring3bis about 4.5 N/mm.

The base plate36of the base30is mounted on a post40disposed on the floor surface of an automated welding line.

(How the Mini Chips and Cap Chips are Stored)

To store mini chips302in the magazine50for spot welding chips of the present invention, the guide pin17is first slid toward the bobbin19side so as to slide the mini chip push-out member12toward the bobbin19side. This makes space in between the mini chip supply port11band mini chip push-out member12, and the plurality of mini chips302are inserted into the mini chip storage portion11aof this space and stored in a line. When the guide pin17is released, the restoring force (biasing force) of the spiral spring14pulls the mini chip push-out member12toward the supply port11bside. The mini chips302stored inside the mini chip storage portion11aare pushed against the end portion11non the side of the mini chip supply port11bof the mini chip storage portion11aby the mini chip push-out member12and retained, so that the mini chips302do not fall off from the mini chip supply port11b.

To store cap chips195in the magazine50for spot welding chips, the guide pin27is first slid toward the bobbin29side so as to slide the cap chip push-out member22toward the bobbin29side. This makes space in between the cap chip supply port11eand cap chip push-out member22, and the plurality of cap chips195are inserted into the cap chip storage portion11dof this space and stored in a line. When the guide pin27is released, the restoring force (biasing force) of the spiral spring24pulls the cap chip push-out member22toward the supply port11eside. The cap chips195stored inside the cap chip storage portion11dare pushed against the end portion11pon the side of the cap chip supply port11eof the cap chip storage portion11dby the cap chip push-out member22and retained, so that the cap chips195do not fall off from the cap chip supply port11e.

A locking mechanism (not shown) is provided at the back of the mini chip push-out member12or cap chip push-out member22, so that when the mini chip push-out member12or cap chip push-out member22is slid to the back, the locking mechanism locks the mini chip push-out member12or cap chip push-out member22and prevents them from sliding to the front. Therefore, even when the guide pin17or guide pin27is released, mini chips302or cap chips195can still be stored into the mini chip storage portion11aor cap chip storage portion11d. After the mini chips302or cap chips195are stored in the mini chip storage portion11aor cap chip storage portion11d, the lock by the locking mechanism is released.

(How the Mini Chips and Cap Chips are Mounted)

Next, how a cap chip195is mounted to an arm191and a mini chip302is mounted to a chip base301using the magazine50for spot welding chips of the present invention will be described.FIGS. 8 to 13show explanatory diagrams of how the mini chips302and cap chips195are mounted.FIGS. 8 to 13are cross sections taken along A-A ofFIG. 1.

As shown inFIG. 8, a welding gun is moved by a robot arm to a position where the mounting portion191aof the arm191coincides with the cap chip supply port11e, while the mounting hole301aof the chip base301coincides with the mini chip supply port11b, with respect to the up and down direction and front to back direction of the magazine50for spot welding chips. That is, in this state, the mounting portion191aof the arm191coincides with the mounting recess195aof the cap chip195, while the mounting portion302bof the mini chip302coincides with the mounting hole301aof the chip base301, with respect to the up and down direction and front to back direction of the magazine50for spot welding chips. Here, the upper face301cof the chip base301is separated by a predetermined distance γ from the end face2cof the cover plate2or the opening plane11mof the mini chip supply port11b.

Next, with the chip base301position being fixed, the arm191is closed toward the chip base301side, whereby the mounting portion191aof the arm191enters the mounting portion195aof the cap chip195, as well as an inner side191bof the arm195makes contact with the abutment portion3fof the pressing pin3c(state shown inFIG. 9).

From the state ofFIG. 9, when the arm191is further closed toward the chip base301side, the inner side191bof the arm191presses the pressing pin3c. As mentioned above, the spring constant of the coil spring33is smaller than that of the coil spring3b, so that the coil spring33contracts more than the coil spring3b. Therefore, the entire magazine body10mounted on the slide member31moves in the direction toward the side plate35, and stops when the end face2cof the cover plate2abuts on the upper face301cof the chip base301(state shown inFIG. 10). In the state ofFIG. 10, the opening plane11mof the mini chip supply port11band the upper face301cof the chip base301coincide with each other. That is, in the state ofFIG. 10, the mini chip supply port11bcommunicates with the mounting hole301aof the chip base301. Due to the structure wherein the coil spring3bis accommodated inside the main body3aand pressed by the pressing pin3c, the coil spring3bdoes not buckle and reliably causes the magazine body10to move toward the side plate35side so that the end face2cof the cover plate2abuts on the upper face301cof the chip base301.

As the chip base301does not move, when the arm191is further closed toward the chip base301side from the state ofFIG. 10, the coil spring3bcontracts while the arm191moves toward the chip base301side, whereby the cap chip195is completely mounted to the mounting portion191aof the arm191and the cap chip195moves toward the mini chip302side to make contact with the abutment portion302a(state shown inFIG. 11).

From the state ofFIG. 11, when the arm191is closed toward the chip base301side, the cap chip195presses the abutment portion302aof the mini chip302, whereby the mini chip302moves toward the chip base301side, causing the mounting portion302bof the mini chip302to enter into the mounting hole301aof the chip base301so that the mini chip302is mounted to the chip base301(state shown inFIG. 12). In the state ofFIG. 11, the mini chip supply port11band the mounting hole301aof the chip base301communicate with each other, so that the mini chip302does not fall off from the mini chip supply port11band the mounting portion302bof the mini chip302can reliably enter into the mounting hole301aof the chip base301.

From the state ofFIG. 12, when the arm191is opened relative to the chip base301, the cap chip195mounted to the arm191is escaped from the cap chip supply port11e, whereupon the cap chips195stored in the cap chip storage portion11dare pushed out by the cap chip push-out member22and supplied to the cap chip supply port11e. At this time, the pressing pin3cseparates from the inner side191cof the arm191so that the magazine body10is freed from the pressure applied by the arm191toward the side plate35side, and the coil spring33presses the slide member31toward the side plate34side so that the magazine body10mounted on the slide member31slides toward the side plate34side. At this time, the mini chip302mounted to the chip base301is escaped from the mini chip supply port11b, whereupon the mini chips302stored in the mini chip storage portion11aare pushed out by the mini chip push-out member12and supplied to the mini chip supply port11b(state shown inFIG. 13). In order for the mini chip302mounted to the chip base301to be completely escaped from the mini chip supply port11b, the above-mentioned predetermined distance γ(shown inFIG. 8) is set larger than the dimension λ from the upper face302cof the chip base301to the distal end of the mini chip302.

With this structure wherein the magazine body10is slid toward the side plate34side by the biasing force of the coil spring33to allow the mini chip302mounted to the chip base301to be escaped from the mini chip supply port11b, there is no need to teach the robot arm that moves the welding gun a complex movement pattern. If the robot arm was operated to cause the mini chip302mounted to the chip base301to escape from the mini chip supply port11b, there would be a possibility that the mini chip302may go off the trajectory and move in contact with the mini chip supply port11b, ending up falling off of the chip base301. The present invention eliminates such a problem.

In the present invention, when the operation of mounting the cap chip195to the arm191and the operation of mounting the mini chip302to the chip base301are complete, cap chips195are supplied to the cap chip supply port11eand mini chips302are supplied to the mini chip supply port11bautomatically.

When there are a fewer number of mini chips302inside the mini chip storage portion11a, the mini chips302are pushed against the end portion11nof the mini chip storage portion11aby the mini chip push-out member12with an almost constant force, since the biasing force of the spiral spring14is almost constant, and therefore the mini chips302will not fall off from the mini chip supply port11b.

Similarly, when there are a fewer number of cap chips195inside the cap chip storage portion11d, the cap chips195are pushed against the end portion11pof the cap chip storage portion11dby the cap chip push-out member22with an almost constant force, since the biasing force of the spiral spring24is almost constant, and therefore the cap chips195will not fall off from the cap chip supply port11e.

In the present invention, the biasing direction of the spiral springs14and24is inverted by means of the pulleys15and25to make it possible to provide the spiral springs14and24on the opposite side of the mini chip supply port11b(cap chip supply port11e), so that the area around the mini chip supply port11band cap chip supply port11eis not bulky and there is no interference with the arm195or chip base301of the welding gun.

A second embodiment will be described withFIG. 14showing a cross sectional view taken along A-A of the second embodiment. The pressing mechanism3of the second embodiment does not use a pressing pin3cand instead, in this embodiment, the base end of the coil spring3bis directly attached to the main body3a. As shown inFIG. 14, the distal end3iof the coil spring3bprotrudes from the opening plane11qof the cap chip supply port11e.

SUMMARY

With a welding gun being not one that is mounted on a robot arm but one that is fixed in an automated welding line, the magazine50for spot welding chips of the present invention is mounted on a robot for use. When mounting a cap chip195or a mini chip302, the robot is operated to move the magazine50for spot welding chips to a position where the mini chip supply port11band the cap chip supply port11eare aligned with the mounting portion191aof the arm191and the mounting hole301aof the chip base301, respectively, and as described above, the arm191is closed toward the chip base301side, whereupon the cap chip195and mini chip302are respectively mounted to the arm191and chip base301of the spot welder.

Although the present invention has been described above in relation to embodiments that are currently believed to be most practical and preferable, it should be understood that the present invention is not limited to the embodiments disclosed in the description of this application but may be changed suitably without departing from the scope of the invention or the basic idea thereof interpreted from the claims and the entire description, and that magazines for spot welding chips with such changes are also included in the technical scope of the invention.