Belt changing device

Abstract

[Problem] To provide a belt replacement device for assisting a robot system in automatically replacing an endless grinding belt in a belt-type grinding tool that is incorporated into the robot system. [Solution] This belt replacement device 10 comprises a pulley-receiving member 22 that has a pulley-pushing recess 20, and a belt-pressing part 24 that is provided to the pulley-receiving member 22 and is adjacent to the pulley-pushing recess 20. The belt-pressing part 24 has a gap 38 through an idle pulley 6 and a tension bar 5 of a belt-type grinding tool 1. In a state in which the idle pulley 6 enters a state of being pushed by the pulley-pushing recess 20 and the tension bar 5 is pressed into a tool body 3, when the belt-type grinding tool 1 is moved so that the idle pulley 6 and the tension bar 5 pass through the gap 38 in the belt-pressing part 24, an endless grinding belt B hooked around the idle pulley 6 and a drive pulley 4 comes into contact with the belt-pressing part 24 and is disconnected from the belt-type grinding tool 1.

Description

[Technical Field]

[0001] The present invention relates to a belt changing device for changing an endless grinding belt of a belt-type grinding tool, and more particularly to a belt changing device for changing an endless grinding belt of a belt-type grinding tool incorporated in a robot system. [Background technology]

[0002] Belt-type grinding tools that rotate an endless grinding belt to perform grinding work have been known for some time. In these belt-type grinding tools, the endless grinding belt is attached between a drive pulley, which is driven by a drive source such as an electric motor or an air motor, and an idle pulley, which is rotatably supported at the end of a tension bar. Typically, the tension bar is biased by a spring or other means in a direction that moves the idle pulley away from the drive pulley, applying a predetermined tension to the endless grinding belt. To replace the endless grinding belt, first, the tension bar is pushed against the spring force to move the idle pulley closer to the drive pulley, thereby releasing the tension applied to the endless grinding belt, and the used endless grinding belt is then removed. A new endless grinding belt is then attached between the drive pulley and the idle pulley, and the tension bar is released to install it. To facilitate this replacement process, belt-type grinding tools equipped with a locking mechanism to hold the tension bar in the pushed-in position have also been developed (see Patent Document 1).

[0003] Conventionally, belt-type grinding tools such as those described above have been held by hand when in use, but in recent years they have also been used by being attached to the tip of a robot arm in a robot system. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6516920 Summary of the Invention [Problem to be solved by the invention]

[0005] When a belt-type grinding tool is incorporated into a robot system and the belt is replaced manually, the robot system must stop operation each time and personnel must be assigned to perform the belt replacement. Therefore, it is desirable for the robot system to be able to automatically perform replacement tasks such as removing and installing the endless grinding belt.

[0006] Therefore, an object of the present invention is to provide a belt changing device that assists the robot system in automatically changing the endless grinding belt of a belt-type grinding tool incorporated into a robot system, particularly in removing the endless grinding belt. [Means for solving the problem]

[0007] That is, the present invention provides: A belt changing device for changing an endless grinding belt of a belt-type grinding tool incorporated in a robot system, the belt-type grinding tool comprising: a tool body having a drive source; a drive pulley that is rotationally driven by the drive source; a tension bar that is held by the tool body so as to be displaceable in a direction perpendicular to the rotation axis of the drive pulley and is biased in a direction away from the drive pulley; and an idle pulley that is rotatably held by the tension bar, the belt changing device comprising: a pulley receiving member having a pulley pressing recess against which an idle pulley of a belt-type grinding tool is pressed; a belt pressing portion provided on the pulley receiving member adjacent to the pulley pressing recess, the belt pressing portion having a gap through which the idle pulley and a tension bar of the belt-type grinding tool can pass; Equipped with Provided is a belt changing device in which the idle pulley of the belt-type grinding tool is pressed against the pulley pressing recess, thereby causing the tension bar to be pressed into the tool body, and when the belt-type grinding tool is moved so that the idle pulley and tension bar pass through the gap in the belt pressing part, the endless grinding belt that has been wound between the idle pulley and drive pulley of the belt-type grinding tool hits the belt pressing part and is released from the belt-type grinding tool.

[0008] In this belt changing device, the idle pulley of the belt-type grinding tool is pressed against the pulley pressing recess to push in the tension bar, and then the belt-type grinding tool is moved so that the idle pulley and tension bar pass through the gap in the belt pressing part, causing the tension-released endless grinding belt to come into contact with the belt pressing part and be released from the belt-type grinding tool. In other words, the removal of the installed endless grinding belt can be completed simply by moving the belt-type grinding tool relative to the belt changing device. Therefore, the endless grinding belt can be easily removed by a robot system without human intervention.

[0009] Also, a base member that holds the pulley receiving member so that the pulley receiving member can be displaced in a direction in which the idle pulley is pressed against the pulley pressing recess; a biasing member that biases the pulley receiving member in a direction away from the base member; The above configuration can be adopted.

[0010] With this configuration, it is possible to prevent an excessive load from being applied to the belt-type grinding tool when the tension bar of the belt-type grinding tool is pushed into a predetermined pushing position.

[0011] Also, a housing to which the base member is fixed and which houses the belt attachment mechanism, the housing having a base having an upper opening, and a lid attached to the base and displaceable between a closed position that closes the upper opening and an open position that opens the upper opening; An opening and closing mechanism for opening and closing the lid portion, When the pulley receiving member is pushed toward the base member to a predetermined pushed-in position against the biasing force of the biasing member, the opening and closing mechanism can displace the lid portion from the closed position to the open position.

[0012] moreover, The pulley receiving member further includes a detection means for detecting that the pulley receiving member has been pushed into the pushed-in position, The opening and closing mechanism comprises a motor, an up-and-down moving part that is moved up and down by the motor, and an engaging part fixed to the lid part, and the motor is driven based on detection by the detection means to move the up-and-down moving part upward, and the up-and-down moving part that has been displaced upward pushes the engaging part to displace the lid part to the open position.

[0013] Additionally, the lid may be pivotally attached to the base by a spring-loaded hinge and biased towards the closed position.

[0014] In environments where belt-type grinding tools are used, there is a possibility that a lot of dust is floating around due to grinding operations, etc., and therefore the belt changing device may also be placed in such an environment. In such cases, dust may adhere to the moving parts and electrical circuitry of the belt changing device, causing malfunctions. In the belt-type grinding tool, as described above, the belt installation mechanism is housed in a housing, and by setting the lid to the open position when the belt is installed, i.e., after the belt is removed, the time the belt installation mechanism and other components are exposed to dust can be shortened. This makes it possible to prevent the occurrence of the above-mentioned malfunctions.

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A belt changing device according to an embodiment of the present invention will now be described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a front view of a belt changing device according to an embodiment of the present invention, showing the internal configuration of a housing as a partial cross-sectional view. FIG. [Figure 2] 2 is a top view of the belt exchanging device of FIG. 1, showing a state in which a cover of a housing is removed. FIG. [Figure 3] 2 is a right side view of the belt exchanging device of FIG. 1, showing in detail the configuration of an opening / closing mechanism disposed inside a housing. FIG. [Figure 4] 1 is a top view of a first state showing the operation of removing the endless grinding belt by the belt removing mechanism of the belt changing device. FIG. [Figure 5] FIG. 5 is a front view of the belt changing device in the state shown in FIG. 4. [Figure 6] FIG. 10 is a top view of a second state showing the operation of removing the endless grinding belt with the belt removing mechanism of the belt changing device. [Figure 7] FIG. 10 is a top view of a third state showing the operation of removing the endless grinding belt with the belt removing mechanism of the belt changing device. [Figure 8] FIG. 8 is a front view of the belt changing device in the state shown in FIG. 7. [Figure 9] 10 is a right side view of the belt changing device with the cover of the housing in the open position by the opening / closing mechanism. FIG. [Figure 10] 1 is a diagram showing a first state of an operation of mounting an endless grinding belt using a belt mounting mechanism of a belt changing device. FIG. [Figure 11] FIG. 10 is a diagram showing a second state of the operation of mounting an endless grinding belt using the belt mounting mechanism of the belt changing device. [Figure 12] FIG. 10 is a diagram showing a third state of the operation of mounting an endless grinding belt using the belt mounting mechanism of the belt changing device. [Figure 13] FIG. 10 is a diagram showing a fourth state of the operation of mounting an endless grinding belt using the belt mounting mechanism of the belt changing device. [Figure 14]FIG. 10 is a diagram showing a fifth state in which the endless grinding belt is mounted by the belt mounting mechanism of the belt changing device. [Figure 15] FIG. 10 is a diagram showing a first state of operation when the spare belt holding section runs out of replacement endless grinding belts. [Figure 16] FIG. 10 is a diagram showing a second state of operation when the spare belt holding section runs out of replacement endless grinding belts. [Figure 17] FIG. 10 is a diagram showing a third state of operation when the spare belt holding section runs out of replacement endless grinding belts. DETAILED DESCRIPTION OF THE INVENTION

[0017] A belt changing device 10 according to one embodiment of the present invention is a device for removing an endless abrasive belt B attached to a belt-type grinding tool 1 incorporated in a robot system, and for attaching another endless abrasive belt to the belt-type grinding tool 1. As shown in FIG. 1-3, the belt changing device 10 includes a housing 12 consisting of a lower base 12-1 and an upper cover 12-2, a belt removing mechanism 14 disposed on the left side of the housing 12, a belt attaching mechanism 16 housed within the housing 12, and an opening / closing mechanism 18 for opening and closing the cover 12-2.

[0018] As shown in FIGS. 1 and 4 , an exemplary belt-type grinding tool 1 using the belt changing device 10 includes a tool body 3 having a motor (drive source) 2, a drive pulley 4 rotatably driven by the motor 2, a tension bar 5 extending in the direction of a longitudinal axis L perpendicular to the rotation axis R of the drive pulley 4, and an idler pulley 6 rotatably held at the tip of the tension bar 5. The tool body 3 is adapted to be attached to a robot arm (not shown) in a robot system. The tool body 3 has a cylindrical holder 7 extending from the drive pulley 4 toward the idler pulley 6. The tension bar 5 is partially housed within the cylindrical holder 7 and is displaceable in the direction of the longitudinal axis L. A spring is disposed within the cylindrical holder 7, and the spring biases the tension bar 5 in a direction away from the drive pulley 4 (to the right as viewed in FIG. 1 ). The belt-type grinding tool 1 further includes an auxiliary pulley 8 ( FIG. 4 ) rotatably attached to the tool body 3. The endless grinding belt B is wound around the drive pulley 4, idle pulley 6, and auxiliary pulley 8, and is attached to the belt-type grinding tool 1 with an appropriate tension applied to it by being pressed from the inside by the idle pulley 6. The belt-type grinding tool 1 further includes a locking mechanism that holds the tension bar 5 pressed into the cylindrical holding portion 7 so that no tension is applied to the endless grinding belt B, and an unlock button 9 (FIG. 1) on the cylindrical holding portion 7 that releases the tension bar 5 from being held by the locking mechanism. Note that the configuration of the belt-type grinding tool 1 described here is an example, and the configuration of the belt-type grinding tool 1 used with the belt changing device 10 is not limited to this.

[0019] As shown in FIGS. 1 and 2 , the belt removal mechanism 14 of the belt replacement device 10 includes a pulley receiving member 22 having a V-shaped pulley pressing recess 20 and a U-shaped belt holder 24 fixed to the upper surface of the pulley receiving member 22. The belt holder 24 may be formed as an integral part of the pulley receiving member 22. The belt removal mechanism 14 further includes a sliding shaft 26 fixed to the pulley receiving member 22, a base member 28 that displaceably holds the pulley receiving member 22 via the sliding shaft 26, and a spring (biasing member) 30 that is set between the pulley receiving member 22 and the base member 28 and biases the pulley receiving member 22 in a direction away from the base member 28 (to the left as viewed in the figure). The base member 28 is fixed to the housing 12 via a mounting plate 32. A photoelectric sensor (detection means) 34 is attached to the mounting plate 32, and a shielding member 36 is attached to the sliding shaft 26. When the pulley receiving member 22 is pushed toward the base member 28 against the biasing force of the spring 30 to a predetermined pushed-in position (FIG. 6), the shielding member 36 comes between the light-emitting portion and the light-receiving portion of the photoelectric sensor 34, blocking the light emitted from the light-emitting portion toward the light-receiving portion, and the photoelectric sensor 34 turns off. Based on the signal from the photoelectric sensor 34 at this time, the belt changing device 10 can detect that the pulley receiving member 22 has been pushed into the predetermined pushed-in position.

[0020] When removing the endless grinding belt B attached to the belt-type grinding tool 1, the position of the belt-type grinding tool 1 is manipulated so that the idle pulley 6 is pressed against the pulley pressing recess 20 of the pulley receiving member 22 via the endless grinding belt B, as shown in Figures 4 and 5. Next, as shown in Figure 6, the idle pulley 6 is pressed against the pulley pressing recess 20 to push the pulley receiving member 22. At this time, the tension bar 5 is pressed into the cylindrical holding portion 7 and locked in the pressed-in position by the locking mechanism. In addition, the shielding member 36 is positioned to block the light from the photoelectric sensor 34. When the tension bar 5 is in the pressed-in position, the tension applied to the endless grinding belt B is released, and the endless grinding belt B becomes slack. 7 and 8, the belt-type grinding tool 1 is retracted to a position where the idle pulley 6 is separated from the pulley pressing recess 20, and then the belt-type grinding tool 1 is moved so that the idle pulley 6 and tension bar 5 pass upward through the gap 38 of the belt pressing part 24. At this time, the endless grinding belt B that had been wound between the idle pulley 6 and the drive pulley 4 hits the lower surface 24a of the belt pressing part 24, and falls off the belt-type grinding tool 1. This completes the removal of the endless grinding belt B from the belt-type grinding tool 1.

[0021] As shown in FIGS. 1 and 3 , the opening / closing mechanism 18 of the belt exchanging device 10 includes a motor 40, a vertically movable unit 42 that is moved up and down by the motor 40, and an engagement unit 44 fixed to the cover 12-2. A pinion gear 46 is attached to the drive shaft of the motor 40, and a rack 48 that meshes with the pinion gear 46 is formed on the vertically movable unit 42. A shielding member 50 is attached to the lower end of the vertically movable unit 42. Two photoelectric sensors 52, 58 are disposed at positions corresponding to the shielding member 50. When the vertically movable unit 42 is in the lower position and the cover 12-2 is in the closed position as shown in FIG. 3 , the shielding member 50 is positioned to block light from the lower photoelectric sensor 52. The cover 12-2 is pivotally attached to the base 12-1 by a spring-loaded hinge 54 and is biased toward the closed position.

[0022] In the belt removing operation described above, when the pulley receiving member 22 is pushed in and the light from the photoelectric sensor 34 associated with the belt removing mechanism 14 is blocked by the shielding member 36, the belt changing device 10 operates to open the cover 12-2 of the housing 12 using the opening / closing mechanism 18. Specifically, the motor 40 of the opening / closing mechanism 18 is driven to move the vertically movable unit 42 upward, and the abutment portion 56 at the tip of the vertically movable unit 42 presses the engagement portion 44 fixed to the cover 12-2, thereby opening the cover 12-2. When the vertically movable unit 42 moves to a position where the shielding member 50 attached to the lower end of the vertically movable unit 42 blocks the light from the upper photoelectric sensor 58, the change in state of the photoelectric sensor 58 is detected and the driving of the motor 40 is stopped. Accordingly, the movement of the vertically movable unit 42 also stops. As a result, the cover 12-2 reaches a predetermined open position, and the upper opening 12-3 of the base 12-1 is opened (FIG. 9).

[0023] 1 and 3, the belt mounting mechanism 16 of the belt changing device 10 includes a spare belt holder 60 for holding a plurality of spare endless grinding belts B1 to B10 arranged in the width direction, and a mounting belt holder 62 for holding the next endless grinding belt B0 to be mounted. The mounting belt holder 62 is composed of a first disk-shaped member 62-1, a second disk-shaped member 62-2, and a third disk-shaped member 62-3, which are arranged in positions corresponding to the drive pulley 4, idle pulley 6, and auxiliary pulley 8, respectively, when the tension bar 5 of the belt-type grinding tool 1 is in the pressed-in position. The first disk-shaped member 62-1 has a diameter slightly larger than the drive pulley 4, the second disk-shaped member 62-2 has a diameter slightly larger than the idle pulley 6, and the third disk-shaped member 62-3 has a diameter slightly larger than the auxiliary pulley 8. The spare belt holder 60 is composed of a first cylindrical member 60-1, a second cylindrical member 60-2, and a third cylindrical member 60-3, which are arranged at positions corresponding to the drive pulley 4, idle pulley 6, and auxiliary pulley 8, respectively, when the tension bar 5 of the belt-type grinding tool 1 to be used is in the pushed-in position. The first cylindrical member 60-1 has approximately the same diameter as the first disk-shaped member 62-1, the second cylindrical member 60-2 has approximately the same diameter as the second disk-shaped member 62-2, and the third cylindrical member 60-3 has approximately the same diameter as the third disk-shaped member 62-3. The first disk-shaped member 62-1 is held by the first cylindrical member 60-1 via a shaft 64-1 so as to be displaceable in the width direction of the endless grinding belt B0 (up and down as viewed in the figure). Similarly, the second disk-shaped member 62-2 is held by the second cylindrical member 60-2 via a shaft 64-2 so as to be displaceable in the vertical direction, and the third disk-shaped member 62-3 is held by the third cylindrical member 60-3 via a shaft 64-3 so as to be displaceable in the vertical direction. The first disk-shaped member 62-1, the second disk-shaped member 62-2, and the third disk-shaped member 62-3 are interconnected by a connecting member 66 so as to move up and down together. The wearing belt holding part 62 is displaceable between a separated position (first position) ( FIG. 1 ) at a predetermined distance from the spare belt holding part 60 and a proximate position (second position) ( FIG. 11 ) close to the spare belt holding part 60. Note that the wearing belt holding part 62 may be in contact with the spare belt holding part 60 or may be slightly separated from it at the proximate position.A spring 68 is built into at least one of the first cylindrical member 60-1, the second cylindrical member 60-2, and the third cylindrical member 60-3 of the spare belt holder 60, and the wearing belt holder 62 is biased toward the separated position by this spring 68. In this embodiment, the wearing belt holder 62 is composed of three disk-shaped members 62-1, 62-2, and 62-3, but each of these may have a different shape or may be formed as a single, integrated member. Similarly, the spare belt holder 60 may also have a different shape or may be formed as a single, integrated member.

[0024] The belt attachment mechanism 16 further includes a first belt support member 70-1 disposed adjacent to the first disk-shaped member 62-1 and a second belt support member 70-2 disposed adjacent to the second disk-shaped member 62-2. The first belt support member 70-1 is L-shaped, with a shaft 72 fixed to its vertical portion. The shaft 72 is held by a housing 74 so as to be horizontally displaceable. A spring 76 is disposed between the shaft 72 and the housing 74, and the first belt support member 70-1 is biased via the shaft 72 in a direction away from the first disk-shaped member 62-1 (to the left as viewed in the figure). A roller 77 is rotatably attached to the left end of the shaft 72, and a cam member 78 is disposed so as to engage with the roller 77. The cam member 78 is disposed vertically displaceable and moves up and down in response to the drive of a solenoid 80 disposed below it. In the state shown in FIG. 1, the solenoid 80 is driven to displace the cam member 78 downward. At this time, the cam member 78 engages with the roller 77 at the inclined cam engagement surface 78a. When the solenoid 80 is deactivated, the cam member 78 moves upward due to the biasing force of a spring (not shown), and the position of the cam engagement surface 78a that engages with the roller 77 changes accordingly. The shaft 72 is then displaced leftward by the biasing force of the spring 76, and the first belt support member 70-1 is displaced away from the first disk-shaped member 62-1. In this manner, the first belt support member 70-1 is displaceable between a support position (FIG. 1) adjacent to the first disk-shaped member 62-1 and a retracted position (FIG. 12) spaced apart from the first disk-shaped member 62-1. The second belt support member 70-2 is configured similarly to operate and is displaceable between a support position (FIG. 1) adjacent to the second disk-shaped member 62-2 and a retracted position (FIG. 12) spaced apart from the second disk-shaped member 62-2. The configuration for moving the first belt support member 70-1 and the second belt support member 70-2 between the support position and the retracted position is not limited to this and can be changed as desired. Also, it is not necessarily required to have two belt support members, and it is also possible to have only one belt support member or three or more belt support members.

[0025] The belt attachment mechanism 16 further includes a button pressing member 82 disposed at a position corresponding to the unlock button 9 of the belt-type grinding tool 1. The button pressing member 82 can be displaced in the vertical direction by a solenoid 84 disposed at the lower portion of the belt changing device 10.

[0026] As shown in FIG. 1 , the belt changing device 10 further includes a belt moving mechanism 86 for moving the endless grinding belts B1-B10 held around the spare belt holding unit 60 along the spare belt holding unit 60. The belt moving mechanism 86 includes a first cylindrical support member 88-1 disposed around the first cylindrical member 60-1, a second cylindrical support member 88-2 disposed around the second cylindrical member 60-2, and a connecting member 90 connecting them. The belt moving mechanism 86 further includes a trapezoidal screw 96 consisting of a screw shaft 92 and a nut 94, and the nut 94 is fixed to the connecting member 90. The screw shaft 92 is connected to a motor 98 disposed below the screw shaft 92 and is rotated by the motor 98. As the screw shaft 92 rotates, the nut 94 moves up and down along the screw shaft 92, and accordingly, the first cylindrical support member 88-1 and the second cylindrical support member 88-2 also move up and down.

[0027] The belt changing device 10 is capable of installing a new endless grinding belt B0 following the above-described belt removal operation. In the initial state, the belt installation mechanism 16 holds the endless grinding belt B around the installation belt holder 62, which is in the separated position. Upon completion of the belt removal operation, the cover 12-2 of the housing 12 is opened by the opening / closing mechanism 18, as shown in FIG. 9. At this point, the first belt support member 70-1 and the second belt support member 70-2 have each been displaced from the separated position to the support position, with their leading ends positioned below the lower side of the endless grinding belt B0. The belt-type grinding tool 1 from which the endless grinding belt B has been removed is then moved so that its drive pulley 4, idle pulley 6, and auxiliary pulley 8 abut against the first disc-shaped member 62-1, the second disc-shaped member 62-2, and the third disc-shaped member 62-3 of the installation belt holder 62, respectively, from above, as shown in FIG. 10. At this time, the belt-type grinding tool 1 is in a state in which the tension bar 5 is held in the pushed-in position. An annular engaging protrusion 100 having a size and shape corresponding to the recess 4a on the side surface of the drive pulley 4 is provided on the upper surface of the first disk-shaped member 62-1. When the belt-type grinding tool 1 is properly positioned and moved onto the attachment belt holding part 62, the engaging protrusion 100 fits into the recess 4a of the drive pulley 4, thereby fixing their relative positions. As shown in FIG. 11 , when the belt-type grinding tool 1 is moved further downward, the first disk-shaped member 62-1, the second disk-shaped member 62-2, and the third disk-shaped member 62-3 of the attachment belt holding part 62 are pushed by the drive pulley 4, the idle pulley 6, and the auxiliary pulley 8, respectively, and are displaced from the separated position to the close position. At this time, the endless grinding belt B0 held around the attachment belt holding part 62 attempts to move downward together with the attachment belt holding part 62, but the first belt support member 70-1 and the second belt support member 70-2 abut against the endless grinding belt B0 and support the lower side of the endless grinding belt B0, restricting the downward movement of the endless grinding belt B0. As a result, the endless grinding belt B0 disengages from the attachment belt holding part 62 and is positioned around the drive pulley 4, idle pulley 6, and auxiliary pulley 8 of the belt-type grinding tool 1, which has moved inside the attachment belt holding part 62 instead.When the first disc-shaped member 62-1 of the wearing belt holding part 62, in particular, is displaced toward the close position, the shielding member 104 attached to the lower end of the extension shaft 102 connected to the shaft 64-1 attached to the first disc-shaped member 62-1 is displaced together with the first disc-shaped member 62-1, and blocks light from the lower photoelectric sensor 106 of two photoelectric sensors 106, 108 arranged nearby. The belt changing device 10 detects that the light from the lower photoelectric sensor 106 has been blocked and determines that the wearing belt holding part 62 has been displaced to the close position.

[0028] Next, as shown in FIG. 12, the belt changing device 10 moves the first belt support member 70-1 and the second belt support member 70-2 to the retracted positions. Then, the button pressing member 82 is displaced upward to press the lock release button 9 of the belt-type grinding tool 1. This releases the tension bar 5 from the locking mechanism of the belt-type grinding tool 1, and the tension bar 5 extends from the tool body 3. As a result, the endless grinding belt B0 is attached around the drive pulley 4, idle pulley 6, and auxiliary pulley 8 while being tensioned. This completes the attachment operation of the endless grinding belt B0 to the belt-type grinding tool 1. Next, the motor 98 of the belt moving mechanism 86 is driven so that the first cylindrical support member 88-1 and the second cylindrical support member 88-2 move upward. This causes the multiple endless grinding belts B1 to B10 held around the spare belt holder 60 to move upward along the spare belt holder 60. As shown in FIG. 13, the topmost endless grinding belt B1 is pushed out of the spare belt holder 60 and moves to the periphery of the adjacent attachment belt holder 62. A pair of photoelectric sensors 110, 112 (FIG. 2) are positioned at the same height as the attachment belt holder 62, which is now in the adjacent position. The photoelectric sensors 110, 112 detect when the endless grinding belt B1 moves to the attachment belt holder 62 and enters between the photoelectric sensors 110, 112, blocking light. This determines that the endless grinding belt B1 has reached its designated position on the attachment belt holder 62. When it is determined that the endless grinding belt B1 has reached its designated position on the attachment belt holder 62, the motor 98 of the belt moving mechanism 86 is stopped. In this way, the next endless grinding belt B1 to be attached is set in the attachment belt holder 62.

[0029] As shown in FIG. 14, the belt-type grinding tool 1 with the endless grinding belt B0 attached moves upward and away from the belt changing device 10. As the belt-type grinding tool 1 moves upward, the attachment belt holding part 62, along with the endless grinding belt B1 held around it, moves to the separated position. When the attachment belt holding part 62 reaches the separated position, the shielding member 104 below the first cylindrical member 60-1 blocks the light from the upper photoelectric sensor 108. The belt changing device 10 detects this change in the state of the photoelectric sensor 108 and determines that the belt-type grinding tool 1 has been released and the attachment belt holding part 62 has returned to the separated position. After a predetermined time has elapsed, the opening / closing mechanism 18 operates to move the cover 12-2 of the housing 12 to the closed position. Specifically, the motor 40 is driven to move the vertically moving part 42 downward. Then, the lid portion 12-2 is displaced toward the closed position by the biasing force of the spring-loaded hinge 54. When the vertically movable portion 42 is displaced to a position where the shielding member 50 attached to the lower end of the vertically movable portion 42 blocks the light from the lower photoelectric sensor 52, the driving of the motor 40 stops. At this time, the lid portion 12-2 has been displaced to the closed position, and is in a state where it closes the upper opening 12-3 of the base portion 12-1. In this way, the belt changing device 10 returns to a standby state waiting for the next belt change. At this time, the first belt support member 70-1 and the second belt support member 70-2 remain in the retracted positions.

[0030] As shown in FIG. 15, a shaft member 114 is disposed within the third cylindrical member 60-3 of the spare belt holder 60 so as to be movable up and down. An engaging member 118 is attached to the upper end of the shaft member 114, protruding outward from a side opening 116 of the third cylindrical member 60-3, and a shielding member 120 is attached to the lower end of the shaft member 114. The shaft member 114 is normally held in a position where the engaging member 118 abuts against the lower end of the side opening 116. In this state, the shielding member 120 is positioned so as not to block light from a photoelectric sensor 122 located nearby. A boosting member 124 is attached to the connecting member 90 of the belt moving mechanism 86 at a position corresponding to the engaging member 118. When at least one endless grinding belt (one endless grinding belt B10 in FIG. 15) is present around the spare belt holder 60, the boosting member 124 is positioned downward and spaced apart from the engaging member 118, as shown in FIG. 15. When the belt moving mechanism 86 has risen to a position where it can move the last endless grinding belt B10 held around the spare belt holder 60 to the periphery of the attachment belt holder 62, the boost member 124 is positioned close to the engaging member 118, as shown in FIG. 16 . Then, when the last endless grinding belt B10 is attached to the belt-type grinding tool 1 and there are no more endless grinding belts around the spare belt holder 60, and the belt moving mechanism 86 moves further upward, the boost member 124 comes into contact with the engaging member 118 and pushes it upward, as shown in FIG. 17 . This causes the shaft member 114 to move upward, and the shielding member 120 attached to its lower end is positioned to shield the light from the photoelectric sensor 122. When it detects that the light from the photoelectric sensor 122 has been shielded, the upward movement of the belt moving mechanism 86 is stopped, and the operator is notified by an LED display, a sound, or the like that there is no more replacement endless grinding belt. The belt moving mechanism 86 then descends to its lowest position, allowing a new endless grinding belt to be added around the spare belt holding section 60. Based on this notification, the worker can add a new endless grinding belt.

[0031] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, in the above embodiment, the belt removal mechanism, belt mounting mechanism, opening / closing mechanism, and belt moving mechanism are incorporated into a single housing. However, they may be arranged and configured separately. The belt mounting mechanism, opening / closing mechanism, and belt moving mechanism are optional additional components and are not necessarily required for the present invention. Furthermore, the actuators for moving each component, such as motors and solenoids, may be replaced with other optional actuators (e.g., air cylinders or linear motors). Furthermore, while photoelectric sensors are used as detection means for detecting the position of each component, other optional means, such as microswitches or proximity switches, may also be used. The layout, size, and shape of each component of the belt changing device can be appropriately modified to suit the belt-type grinding tool to be used. For example, the above embodiment is directed to a belt-type grinding tool equipped with an auxiliary pulley. However, if a belt-type grinding tool without an auxiliary pulley is to be used, the configuration may omit the third disc-shaped member or third cylindrical member corresponding to the auxiliary pulley. Furthermore, in the above embodiment, the belt changing device is configured to be controlled independently, but it may be connected to a robot system for communication and controlled by the robot system, in which case the timing of opening and closing the lid by the opening and closing mechanism may be controlled by the robot system. [Explanation of symbols]

[0032] 1 Belt grinding tool 2 Motor (drive source) 3 Tool body 4 drive pulley 4a Recess 5 Tension bar 6 idle pulley 7 Cylindrical holding part 8 Auxiliary pulley 9 Unlock button 10 Belt changing device 12. Case 12-1 Base 12-2 Lid part 12-3 Top opening 14 Belt removal mechanism 16 Belt attachment mechanism 18 Opening and closing mechanism 20 Pulley pressing recess 22 Pulley support member 24 Belt holder 24a Bottom side 26 Sliding shaft 28 Base material 30 Spring (biasing member) 32 Mounting plate 34 Photoelectric sensor (detection means) 36 Shielding material 38 Gap 40 Motor 42 Vertical movement section 44 Engagement part 46 Pinion gear 48 racks 50 Shielding material 52 Photoelectric Sensor 54 Spring-loaded hinge 56 Contact part 58 Photoelectric Sensor 60 Spare belt holder 60-1 First cylindrical member 60-2 Second cylindrical member 60-3 Third cylindrical member 62 Attachment belt holder 62-1 First circular plate member 62-2 Second disc-shaped member 62-3 Third disc-shaped member 64-1 shaft 64-2 shaft 64-3 shaft 66 Connecting member 68 Spring 70-1 First belt support member 70-2 Second belt support member 72 Shaft 74 Housing 76 Spring 77 Laura 78 Cam member 78a Cam engagement surface 80 Solenoid 82 Button pressing member 84 Solenoid 86 Belt moving mechanism 88-1 First cylindrical support member 88-2 Second cylindrical support member 90 Connecting member 92 screw shaft 94 Nut 96 Trapezoidal screw 98 Motor 100 Engagement protrusion 102 Extension shaft 104 Shielding material 106 Photoelectric Sensor 108 Photoelectric Sensor 110 Photoelectric Sensor 112 Photoelectric Sensor 114 Shaft member 116 Side opening 118 Engagement member 120 Shielding material 122 Photoelectric Sensor 124 Push-up member B, B0, B1~B10 endless grinding belt L Longitudinal axis R rotation axis

Claims

1. A belt changing device for changing an endless grinding belt of a belt-type grinding tool incorporated in a robot system, the belt-type grinding tool comprising: a tool body having a drive source; a drive pulley that is rotationally driven by the drive source; a tension bar that is held by the tool body so as to be displaceable in a direction perpendicular to the rotation axis of the drive pulley and is biased in a direction away from the drive pulley; and an idle pulley that is rotatably held by the tension bar, the belt changing device comprising: a pulley receiving member having a pulley pressing recess against which an idle pulley of a belt-type grinding tool is pressed; a belt pressing portion provided on the pulley receiving member adjacent to the pulley pressing recess, the belt pressing portion having a gap through which the idle pulley and a tension bar of the belt-type grinding tool can pass; Equipped with The idle pulley of the belt-type grinding tool is pressed against the pulley pressing recess, thereby causing the tension bar to be pressed into the tool body, and when the belt-type grinding tool is moved so that the idle pulley and tension bar pass through the gap in the belt pressing part, the endless grinding belt that has been wound between the idle pulley and the drive pulley of the belt-type grinding tool hits the belt pressing part and is released from the belt-type grinding tool.

2. a base member that holds the pulley receiving member so that the pulley receiving member can be displaced in a direction in which the idle pulley is pressed against the pulley pressing recess; a biasing member that biases the pulley receiving member in a direction away from the base member; The belt changing device of claim 1 , comprising:

3. a housing to which the base member is fixed and which houses the belt attachment mechanism, the housing having a base having an upper opening, and a lid attached to the base and displaceable between a closed position that closes the upper opening and an open position that opens the upper opening; An opening and closing mechanism for opening and closing the lid portion, 3. The belt changing device according to claim 2, wherein the opening / closing mechanism displaces the lid portion from the closed position to the open position when the pulley receiving member is pushed toward the base member to a predetermined pushed-in position against the biasing force of the biasing member.

4. The pulley receiving member further includes a detection means for detecting that the pulley receiving member has been pushed into the pushed-in position, 4. The belt changing device according to claim 3, wherein the opening / closing mechanism comprises a motor, a vertically moving part that is moved up and down by the motor, and an engaging part fixed to the lid part, and the motor is driven to move the vertically moving part upward based on detection by the detection means, and the vertically moving part that has been displaced upward presses the engaging part to displace the lid part to the open position.

5. 4. The belt changing device of claim 3, wherein the lid is pivotally attached to the base by a spring-loaded hinge and biased toward the closed position.

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