Pallet tipping prevention mechanism and automatic pallet exchange device

Abstract

The objective is to provide a pallet tipping prevention mechanism and an automatic pallet exchange device that are applicable to APCs with vertical constraints and also offer excellent durability and dust resistance. [Solution] The pallet tipping prevention mechanism 10 comprises a locking part 11 and a release part 12. The locking part 11 is provided on the lower surface of the fork part 5 so as to be movable in the axial direction and comprises an input / output shaft 15 that can engage with the pallet 40 in the forward position, an anti-rotation shaft 16 provided parallel to and integral with the input / output shaft 15 so as to be movable in the forward position and restricts the tangential rotation of the input / output shaft 15, and a coil spring 25 that biases the input / output shaft 15 to the forward position. The release part 12 is provided on the base 7 at a position that is on the extension line of the input / output shaft 15 when the slewing arm 4 is in the lowered position and comprises a cylinder rod 34 that can move between a protruding position that pushes the input / output shaft 15 from the forward position to the retracted position to release the engagement between the input / output shaft 15 and the pallet 40, and a retracted position that is separated from the input / output shaft 15 in the forward position.

Description

Technical Field

[0001] The present disclosure relates to a pallet fall prevention mechanism and an automatic pallet changer that can prevent the fall of a pallet that may occur in an automatic pallet changer provided in a machine tool, and can reduce problems such as misalignment, tilting, and dropping.

Background Art

[0002] In a horizontal machining center with an automatic pallet changer (hereinafter referred to as APC), generally, by rotating the APC forks on which pallets are placed on both sides, pallet exchange is realized between the setup station side and the machining chamber. Since the pallet exchange time is non-cutting time, for the purpose of improving productivity, the turning speed of the APC forks is increased as much as possible to shorten the pallet exchange time. Since the pallet is simply placed on the APC forks, when the balance of the moments of gravity and centrifugal force is disrupted during the rotation of the APC forks, the pallet will fall. When the pallet falls, there are cases where the workpiece collides with the cover of the APC, and it may take time to recover. Therefore, in order to avoid the fall of the pallet, for example, in the instruction manual, the center of gravity position that can be loaded on the APC is clearly indicated. However, there are many users who do not grasp the details of the center of gravity of the pallet and the workpiece. Therefore, as a result of attaching a workpiece with a center of gravity outside the allowable range, there are not a few cases where the pallet falls during the rotation of the APC forks.

[0003] As a measure to prevent the fall of the pallet, for example, as shown in FIG. In such a fall prevention measure, when the APC fork 102 rotates, even if the pallet 100 is about to fall, the hook 101 will catch on the APC fork 102, so that the fall of the pallet 100 can be prevented.

[0004] On the other hand, to improve productivity, one option is to introduce a flexible manufacturing system (hereinafter referred to as FMS). When an FMS is introduced and pallets move between machines, it is necessary to unload the pallets from the APC located on the setup station side. In this case, as shown in Figure 8, an FMS generally uses a method in which the FMS arm 103 lifts the pallet 100 from below. However, the use of the hook 101 as a pallet tipping prevention device, as described above, cannot be adopted because the hook 101 would get caught on the FMS arm 103 when the FMS arm 103 lifts the pallet 100 from below. For this reason, in many existing horizontal machining centers, even if an FMS is introduced, a pallet tipping prevention device is not installed. However, if a pallet tipping prevention device is not installed, even if productivity is improved by the FMS, there is a concern that pallet tipping may occur depending on the workpiece, making it difficult to increase production efficiency.

[0005] Therefore, in Patent Document 1, the applicant discloses an automatic pallet changing device in which an anti-tipping device can be released by an air cylinder. The pallet anti-tipping mechanism provided in the automatic pallet changing device described in Patent Document 1 comprises an output shaft provided on the fork portion so as to be movable axially and reciprocating, and capable of engaging with a hook provided on the underside of the pallet in the forward position, and an input shaft provided parallel to and integral with the output shaft so as to be movable reciprocating. The pallet anti-tipping mechanism also comprises a coil spring provided on the fork portion that biases the output shaft to the forward position, and an external cylinder provided on the fork portion so as to be on the extension line with the input shaft when the slewing arm is in the lowered position, and equipped with a piston rod that can move between a protruding position that pushes the input shaft from the forward position to the retracted position to release the engagement of the pallet with the hook by the output shaft, and a retracted position that is separated from the input shaft in the forward position.

[0006] In the anti-tipping device described in Patent Document 1, the piston rod is positioned in the retracted position when a pallet is placed on the fork. In this state, the output shaft is engaged with the hook on the underside of the pallet, thus preventing the pallet from tipping over. On the other hand, when releasing the anti-tipping mechanism for the pallet, the piston rod moves to the protruding position while compressing the coil spring that biases the input shaft to the forward position. That is, the input shaft moves from the forward position to the retracted position. At this time, the output shaft, which is connected to the input shaft via an adapter, also moves simultaneously, releasing the engagement between the output shaft and the hook on the underside of the pallet. When the engagement between the output shaft and the hook on the underside of the pallet is released, the anti-tipping device will not get caught on the hook on the underside of the pallet when the pallet is lifted. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 7152335 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, in the conventional anti-tipping devices described above, the input shaft and output shaft are arranged vertically. Therefore, for example, even if one attempts to apply an APC equipped with the conventional anti-tipping device to a small machine tool, it is possible that, depending on the base structure of the APC, it may not be possible to secure vertical space to arrange the input shaft and output shaft. In such cases, the conventional APC equipped with the conventional anti-tipping device cannot be applied.

[0009] Therefore, the purpose of this disclosure is to provide a pallet tipping prevention mechanism and an automatic pallet exchange device that are applicable to APCs with vertical constraints and also have excellent durability and dustproof properties. [Means for solving the problem]

[0010] To solve the above problems, the first configuration of the present disclosure is a pallet tipping prevention mechanism provided in an automatic pallet exchange device that has a swivel arm with fork sections at both ends mounted on a base, and allows pallets placed on the fork sections to be exchanged by the horizontal swivel and lifting movements of the swivel arm, and which engages with the pallet when the swivel arm rotates horizontally to prevent the pallet from tipping over, comprising a locking section provided on the lower surface of the fork section and a release section provided below the fork section, wherein the locking section is provided so as to be able to move back and forth in the axial direction while rotation in the tangential direction is restricted and comprises an input / output shaft that can engage with the pallet in the forward position and a biasing means that biases the input / output shaft to the forward position, and the release section is provided on the base at a position in front of the input / output shaft when the swivel arm is in the lowered position and comprises a cylinder rod that can move between a protruding position that pushes the input / output shaft from the forward position to the retracted position to release the engagement of the input / output shaft with the pallet and a retracted position that is separated from the input / output shaft in the forward position. Another aspect of the first configuration of the present disclosure is characterized in that, in the locking section, the input / output shaft and the biasing means are housed in a case provided on the lower side of the fork section, except for the tip of the input / output shaft, and the tip of the input / output shaft is sealed by a shielding member, and in the unlocking section, the cylinder rod is housed in an anti-tipping release cylinder provided on a base, except for the tip, and the tip of the cylinder rod is also sealed by a shielding member. Another aspect of the first configuration of the present disclosure is characterized in that, in the above configuration, the locking portion is housed in a case and is provided to be movable back and forth integrally with the input / output shaft, and includes an anti-rotation shaft that restricts tangential rotation of the input / output shaft. Another aspect of the first configuration of this disclosure is characterized in that, in the above configuration, the input / output shaft and the anti-rotation shaft are connected in parallel. Another aspect of the first configuration of this disclosure is characterized in that, in the above configuration, the input / output shaft and the anti-rotation shaft are arranged horizontally side by side. To solve the above problems, the second configuration of the present disclosure is an automatic pallet changing device equipped with a swivel arm having fork sections at both ends mounted on a base, which allows for the exchange of pallets placed on the fork sections by the horizontal swivel and lifting movements of the swivel arm, and which is equipped with a pallet tipping prevention mechanism that engages with the pallet when the swivel arm rotates horizontally to prevent the pallet from tipping over, wherein the pallet tipping prevention mechanism comprises a locking section provided on the lower surface of the fork section and a release section provided below the fork section, the locking section is equipped with an input / output shaft that is able to move back and forth in the axial direction while rotation in the tangential direction is restricted and can engage with the pallet in the forward position, and a biasing means that biases the input / output shaft to the forward position, and the release section is equipped with a pallet tipping prevention mechanism equipped with a cylinder rod that is movable between a protruding position that pushes the input / output shaft from the forward position to the retracted position to release the engagement of the input / output shaft with the pallet, and a retracted position that is separated from the input / output shaft in the forward position. Another aspect of the second configuration of the present disclosure is characterized in that, in the above configuration, in the locking section, the input / output shaft and the biasing means are housed in a case provided on the lower side of the fork section, except for the tip of the input / output shaft, and the tip of the input / output shaft is sealed by a shielding member, and in the unlocking section, the cylinder rod is housed in an anti-tipping release cylinder provided on a base, except for the tip, and the tip of the cylinder rod is also sealed by a shielding member. Another aspect of the second configuration of the present disclosure is characterized in that, in the above configuration, the locking portion is housed in a case and is provided to be movable back and forth integrally with the input / output shaft, and includes an anti-rotation shaft that restricts tangential rotation of the input / output shaft. Another aspect of the second configuration of this disclosure is characterized in that, in the above configuration, the input / output shaft and the anti-rotation shaft are connected in parallel. Another aspect of the second configuration of this disclosure is characterized in that, in the above configuration, the input / output shaft and the anti-rotation shaft are arranged horizontally side by side. [Effects of the Invention]

[0011] According to this disclosure, the pallet tipping prevention mechanism comprises a locking section having input / output shafts whose rotation in the tangential direction is restricted, and an unlocking section having a cylinder rod for moving the input / output shafts. Therefore, it is compact in the height direction and can be installed in a space-saving manner. Accordingly, the pallet tipping prevention mechanism and automatic pallet exchange device of this disclosure can also be applied to APCs that have vertical constraints. Furthermore, the input / output shaft and the cylinder rod are located on the same coaxial extension line. Therefore, uneven contact does not occur in the sliding bearing. Consequently, the pallet tipping prevention mechanism and automatic pallet changing device of this disclosure have excellent durability. Furthermore, the input / output shaft and the cylinder rod are sealed by a dust seal. Therefore, the pallet tipping prevention mechanism and automatic pallet changing device of this disclosure also have excellent dust resistance. [Brief explanation of the drawing]

[0012] [Figure 1] This is an explanatory diagram showing the automatic pallet exchange device as viewed from the setup station. [Figure 2] This is an explanatory diagram from Figure 1, with everything except the swivel arm and base omitted. [Figure 3] This is an enlarged explanatory diagram showing the inside of the circular frame A in Figure 2. [Figure 4] This is a horizontal cross-sectional view of the pallet tipping prevention mechanism in the locked state. [Figure 5] This is a horizontal cross-sectional view of the pallet tipping prevention mechanism in the unlocked state. [Figure 6] This is an enlarged explanatory diagram showing the mechanism inside the circular frame A in Figure 2 in the unlocked state. [Figure 7] This is an explanatory diagram showing conventional pallet protection measures. [Figure 8] This is an explanatory diagram showing how pallet exchange is performed using FMS (Fleet Management System). [Modes for carrying out the invention]

[0013] The embodiments of this disclosure will be described below with reference to the drawings. FIG. 1 shows an automatic pallet changer 1 provided in a horizontal machining center as viewed from the side of the setup station 2. The automatic pallet changer 1 is horizontally rotatable about a swivel shaft 8 on a base 3 by a motor and a lifting mechanism (not shown), and includes a swivel arm 4 that moves up and down. The automatic pallet changer 1 exchanges a pallet 40 between a machining chamber and the setup station 2 by the swivel arm 4. The swivel of the swivel arm 4 is performed while the swivel arm 4 is in an upward state. Fork portions 5 for placing and supporting the pallet 40 are provided at both ends of the swivel arm 4, respectively. In FIG. 1, only one end side of the fork portion 5 is shown. A partition cover 6 for partitioning between the machining chamber and the setup station 2 is provided on the upper surface of the swivel arm 4. In FIG. 1, the description on the machining chamber side of the partition cover 6 is omitted.

[0014] Further, as shown in FIGS. 1, 2, and 3, the automatic pallet changer 1 is provided with a pallet fall prevention mechanism 10 so that when the swivel arm 4 swivels during the exchange of the pallet 40, problems such as the pallet 40 falling from the fork portion 5, displacement, tilting, and dropping do not occur. The pallet fall prevention mechanism 10 includes a lock portion 11 provided on the lower surface of the fork portion 5 and a lock release portion 12 provided on the base 7 of the setup station 2.

[0015] As shown in FIG. 4, the lock portion 11 includes a case 13 fixed to the lower surface of the fork portion 5 and a lock body 14 housed in the case 13. The locking body 14 includes an input / output shaft 15 in the shape of a round bar extending in the left-right direction and a rotation prevention shaft 16. The input / output shaft 15 and the rotation prevention shaft 16 are arranged horizontally side by side, and the rear end portions thereof are connected via an adapter 17 so as to be parallel to each other on the inner side. Further, the left end portion, which is the tip of the input / output shaft 15, penetrates the case 13 and is accommodated in a state of protruding from the front surface of the case 13 so as to be able to move forward and backward in the left-right direction. As shown in FIGS. 2 and 3, an inverted L-shaped anti-tipping hook 18 extending outward is provided at the left end portion of the input / output shaft 15. Since the input / output shaft 15 and the rotation prevention shaft 16 are interlocked via the adapter 17, a space for allowing the rotation prevention shaft 16 and the adapter 17 to move forward and backward in the left-right direction is formed in the case 13. The right end portion of the space is sealed by a rear cover 19. Further, a ring-shaped stopper 20 is formed at the intermediate portion of the input / output shaft 15. A front cover 21 that abuts against the stopper 20 to regulate the protruding amount of the input / output shaft 15 is provided at the left end portion of the case 13. The input / output shaft 15 and the rotation prevention shaft 16 are respectively supported by slide bearings 22, 22 in the case 13. Further, the protruding portion of the input / output shaft 15 from the case 13 is sealed by a dust seal 23 to prevent foreign matter from entering the inside of the case 13.

[0016] Also, in the case 13, a large-diameter hole 24 in which the stopper 20 can move forward and backward is formed in the accommodating portion of the input / output shaft 15. A coil spring 25 as a biasing means externally mounted on the input / output shaft 15 is accommodated in the large-diameter hole 24 on the right side of the stopper 20. Therefore, in the normal state of the locking body 14, the coil spring 25 presses the stopper 20 to the left, and the stopper 20 is biased to the forward position where it abuts against the front cover 21.

[0017] As described above, the input / output shaft 15 is constrained by the sliding bearing 22 attached to the front cover 21 and case 13 so that it cannot move in any direction other than the axial left-right direction. Furthermore, the input / output shaft 15 is biased to the left by the coil spring 25. The anti-rotation shaft 16 is also held by the sliding bearing 22 attached to the case 13. Therefore, the anti-rotation shaft 16 is also constrained to move in any direction other than the axial left-right direction. In addition, the input / output shaft 15 and the anti-rotation shaft 16 are fixed together via an adapter 17. Thus, the input / output shaft 15 can move in the left-right direction, while its rotation in the tangential direction is restricted by the anti-rotation shaft 16. In this way, the posture of the anti-tipping hook 18 is maintained.

[0018] Furthermore, as shown in Figures 2 and 3, the underside of the pallet 40 is provided with an L-shaped pallet-side hook 41 that extends inward when the pallet is placed on the fork section 5. When the input / output shaft 15 of the locking body 14 is in the forward position, the anti-tipping hook 18 of the input / output shaft 15 engages with the pallet-side hook 41. Therefore, even if the pallet 40 begins to tip over due to centrifugal force when the swivel arm 4 is rotated during replacement of the pallet 40, the pallet-side hook 41 catches on the anti-tipping hook 18, preventing the pallet 40 from tipping over.

[0019] Meanwhile, in the lock release section 12, the anti-tipping release cylinder 30 is horizontally supported on the base 7 via a bracket 31. As shown in Figure 4, the anti-tipping release cylinder 30 has a piston 33 in the cylinder chamber 32, with the right end of the cylinder rod 34, which is located on the coaxial extension of the input / output shaft 15 of the lock section 11 when the slewing arm 4 is in the lowered position, protruding to the right. By supplying a predetermined driving force, such as compressed air, to the cylinder chamber 32 in front of and behind the piston 33, the piston 33 can be moved back and forth in the axial direction, which is left and right, and the cylinder rod 34 can be moved back and forth. The protruding portion of the cylinder rod 34 in the anti-tipping release cylinder 30 may be sealed by a shielding member such as a dust seal 35 to prevent foreign matter from entering the inside of the anti-tipping release cylinder 30.

[0020] Furthermore, the locking portion 11 is covered by an L-shaped cover 36 attached to the fork portion 5, as shown by the dashed line in Figures 2 and 3. The cover 36 is formed to also cover the unlocking portion 12 when the swivel arm 4 is stopped. In addition, the cover 36 has a through hole 37 that allows the anti-tipping hook 18 to move in conjunction with the forward and backward movement of the input / output shaft 15, and the portion of the anti-tipping hook 18 that engages with the pallet-side hook 41 protrudes from the inside to the outside of the cover 36. The portion of the anti-tipping hook 18 that protrudes outside the cover 36 through the through hole 37 may be sealed with a shielding member to prevent foreign matter from entering the inside of the cover 36.

[0021] In the state shown in Figure 4, the piston 33 has moved to the left, and the cylinder rod 34 is in the retracted position. In the retracted position, the cylinder rod 34 is separated from the input / output shaft 15 in the forward position. When the piston 33 moves to the right due to the driving force, as shown in Figures 5 and 6, the cylinder rod 34 comes into contact with the input / output shaft 15, and pushes the input / output shaft 15 into the case 13 of the locking body 14. As a result, when the input / output shaft 15 is pushed into the case 13, the anti-tipping hook 18 also moves to the right, and the engagement between the anti-tipping hook 18 and the pallet-side hook 41 is released. The position of the input / output shaft 15 when it is pushed in by the cylinder rod 34 and the engagement between the anti-tipping hook 18 and the pallet-side hook 41 is released is the retracted position of the input / output shaft 15 in this disclosure. Also, the position of the cylinder rod 34 when the input / output shaft 15 is moved to the retracted position is the protruding position of the cylinder rod 34 in this disclosure.

[0022] In the automatic pallet exchange device 1 configured as described above, under normal circumstances, when the pallet 40 is placed on the fork section 5, the piston 33 of the lock release section 12 in the pallet tipping prevention mechanism 10 is positioned in the retracted position of the cylinder chamber 32 by pneumatic pressure, as shown in Figure 4. That is, the cylinder rod 34 and the input / output shaft 15 are separated. On the other hand, when the cylinder rod 34 and the input / output shaft 15 are separated, the lock body 14 in the lock section 11 is in the forward position. In this state, the tipping prevention hook 18 provided on the input / output shaft 15 is engaged with the pallet-side hook 41 of the pallet 40. Hereinafter, the state in which the tipping prevention hook 18 and the pallet-side hook 41 are engaged will be referred to as the locked state of the pallet 40. If the pallet 40 is locked, when replacing the pallet 40, even if the swivel arm 4 rises and rotates horizontally, the engagement between the anti-tipping hook 18 and the pallet-side hook 41 is maintained, thus preventing the pallet 40 from tipping over and reducing the occurrence of problems such as displacement, tilting, and falling.

[0023] On the other hand, when removing the pallet 40 at the setup station 2, the piston 33 of the lock release unit 12 moves forward by air pressure, causing the cylinder rod 34 to protrude. Then, in the lock unit 11, the lock body 14 is pushed into the case 13 together with the input / output shaft 15, as shown in Figures 5 and 6. As a result, the anti-tipping hook 18 of the input / output shaft 15 moves to the right to a position where it does not overlap with the pallet-side hook 41 when viewed from above. In other words, the engagement between the anti-tipping hook 18 and the pallet-side hook 41 is released. Hereafter, the state in which the engagement between the anti-tipping hook 18 and the pallet-side hook 41 is released will be referred to as the unlocked state of the pallet 40. By putting the pallet 40 in the unlocked state, the pallet 40 can be removed from the fork unit 5 without the anti-tipping hook 18 and the pallet-side hook 41 interfering with each other. Therefore, in the unlocked state, for example, when the FMS device lifts up the pallet 40, the anti-tipping hook 18 will not get caught on the pallet-side hook 41, thus enabling smooth use of the FMS.

[0024] When the pallet 40 is placed again, the piston 33 is retracted, and the cylinder rod 34 is also retracted. As the cylinder rod 34 retracts, the input / output shaft 15 returns to the forward position together with the locking body 14 due to the biasing force of the coil spring 25. As the input / output shaft 15 moves forward, the anti-tipping hook 18 moves and engages with the pallet-side hook 41, thereby securing the newly placed pallet 40.

[0025] As described above, in the automatic pallet exchange device 1 and the pallet tipping prevention mechanism 10, the cylinder rod 34 is positioned on the coaxial extension line of the input / output shaft 15. Therefore, the cylinder rod 34 contacts or separates from the input / output shaft 15 in the axial direction in both the locked and unlocked states of the pallet 40, causing the input / output shaft 15 to move back and forth only in the axial direction. In other words, no external force is applied to the input / output shaft 15 and the coil spring 25 in an oblique direction to the axial direction. Therefore, uneven contact with the sliding bearing 22 is less likely to occur, and uneven wear can be prevented, resulting in excellent durability for the automatic pallet exchange device 1 and the pallet tipping prevention mechanism 10. Furthermore, both the input / output shaft 15 and the cylinder rod 34 are sealed by dust seals 23 and 35, so that the internal mechanisms of the locking part 11 and the unlocking part 12 are not exposed. In addition, the pallet tipping prevention mechanism 10 itself is covered by a cover 36. Therefore, the automatic pallet exchange device 1 and the pallet tipping prevention mechanism 10 also have excellent dust resistance. Furthermore, in the locking section 11, the two input / output shafts 15 and the anti-rotation shaft 16 only need to be arranged horizontally and parallel to each other, resulting in a compact design in the height direction and enabling installation in a space-saving manner. Therefore, the pallet tipping prevention mechanism 10 can also be applied to APCs that have vertical constraints.

[0026] The configuration of the tool spindle device in this disclosure is not limited in any way to the embodiments described above, and can be modified as necessary without departing from the spirit of the invention. For example, in the locking mechanism, the structure of the input / output shaft and the anti-rotation shaft is not limited to the above form; it may be a square rod or a plate instead of a round rod. If the input / output shaft is a square rod or a polygonal rod and can prevent rotation in the tangential direction on its own, the anti-rotation shaft may be omitted. Furthermore, the connection structure of the two shafts in the locking mechanism can also be changed as appropriate; for example, one end of the shaft may be bent into an L shape and connected to the other shaft without using an adapter. In addition, the locking mechanism may have a projection on the adapter that protrudes in the left-right direction as the anti-rotation shaft. Moreover, it is desirable that the input / output shaft and the anti-rotation shaft be arranged horizontally and parallel, but they may also be arranged vertically. Furthermore, the input / output shaft and the anti-rotation shaft may each have different structures. Furthermore, the coil spring may be provided on the anti-rotation shaft instead of the input / output shaft, or on both the input / output shaft and the anti-rotation shaft. In addition, the locking mechanism may be structured to bias the entire locking body by providing a biasing means such as a coil spring at the rear of the adapter. Furthermore, the engagement means between the pallet and the locking part, as indicated by the anti-tipping hook and the pallet-side hook, is not limited to a hook shape as long as the locking part and the pallet can engage. For example, a projection may be formed downward from the bottom surface of the pallet, and an insertion part such as a through hole or a bottomed hole may be provided in the projection, and an insertion part that can be inserted into the insertion part may be provided on the input / output shaft of the locking part. Moreover, the insertion part may be provided on the pallet itself. Furthermore, the cylinder rod in the unlocking mechanism can also be modified in shape, similar to the input / output shaft. Moreover, the driving force of the cylinder rod in the unlocking mechanism is not limited to air. In addition, the unlocking mechanism may be provided on the underside of the fork section. [Explanation of Symbols]

[0027] 1. Automatic pallet exchange device, 2. Setup station, 3. Base, 4. Swivel arm, 5. Fork section, 7. Base, 10. Pallet tipping prevention mechanism, 11. Lock section, 12. Lock release section, 13. Case, 14. Lock body, 15. Input / output shaft, 16. Anti-rotation shaft, 18. Tipping prevention hook, 23, 35. Dust seal (shielding member), 25. Coil spring, 30. Tipping prevention release cylinder, 33. Piston, 34. Cylinder rod, 40. Pallet, 41. Pallet side hook.

Claims

1. An automatic pallet exchange device is provided with a swivel arm having fork sections at both ends mounted on a base, and the pallet placed on the fork sections can be exchanged by the horizontal swivel and lifting movements of the swivel arm, and a pallet tipping prevention mechanism is provided to engage with the pallet when the swivel arm rotates horizontally to prevent the pallet from tipping over, The fork portion comprises a locking portion provided on the lower surface of the fork portion and a lock release portion provided below the fork portion. The locking portion is provided to be able to move back and forth in the axial direction while rotation in the tangential direction is restricted, and comprises an input / output shaft that can engage with the pallet in the forward position, and a biasing means for biasing the input / output shaft to the forward position. The pallet tipping prevention mechanism is characterized in that the unlocking part is provided on the base at a position in front of the input / output shaft when the pivot arm is in a lowered position, and comprises a cylinder rod that is movable between a protruding position that pushes the input / output shaft from the forward position to the retracted position to release the engagement of the input / output shaft with the pallet, and a retracted position that is separated from the input / output shaft in the forward position.

2. In the locking section, the input / output shaft and the biasing means are housed in a case provided on the lower side of the fork section, except for the tip of the input / output shaft, and the tip of the input / output shaft is sealed by a shielding member. The pallet tipping prevention mechanism according to claim 1, characterized in that, in the lock release section, the cylinder rod is housed in a tipping prevention release cylinder provided on the base except for its tip, and the tip of the cylinder rod is also sealed by a shielding member.

3. The pallet tipping prevention mechanism according to claim 2, characterized in that the locking portion is housed in the case and is provided to be movable back and forth integrally with the input / output shaft, and includes a rotation-preventing shaft that restricts tangential rotation of the input / output shaft.

4. The pallet tipping prevention mechanism according to claim 3, characterized in that the input / output shaft and the anti-rotation shaft are connected in parallel.

5. The pallet tipping prevention mechanism according to claim 3 or 4, characterized in that the input / output shaft and the anti-rotation shaft are arranged horizontally side by side.

6. An automatic pallet exchange device is provided, comprising a swivel arm having fork sections at both ends mounted on a base, the pallet placed on the fork sections being replaceable by the horizontal swivel and vertical movement of the swivel arm, and a pallet tipping prevention mechanism that engages with the pallet when the swivel arm rotates horizontally to prevent the pallet from tipping over, The pallet tipping prevention mechanism comprises a locking part provided on the lower surface of the fork portion and a lock release part provided below the fork portion. The locking portion is provided to be able to move back and forth in the axial direction while rotation in the tangential direction is restricted, and comprises an input / output shaft that can engage with the pallet in the forward position, and a biasing means for biasing the input / output shaft to the forward position. The automatic pallet changing device is characterized in that the unlocking part is provided on the base at a position in front of the input / output shaft when the pivot arm is in a lowered position, and comprises a pallet tipping prevention mechanism that includes a cylinder rod that is movable between a protruding position that pushes the input / output shaft from the forward position to the retracted position to release the engagement of the input / output shaft with the pallet, and a retracted position that is spaced away from the input / output shaft in the forward position.

7. In the locking section, the input / output shaft and the biasing means are housed in a case provided on the lower side of the fork section, except for the tip of the input / output shaft, and the tip of the input / output shaft is sealed by a shielding member. The automatic pallet changing device according to claim 6, characterized in that, in the lock release section, the cylinder rod is housed in an anti-tipping release cylinder provided on the base except for its tip, and the tip of the cylinder rod is also sealed by a shielding member.

8. The automatic pallet changing device according to claim 7, characterized in that the locking portion is housed in the case and is provided to be movable back and forth integrally with the input / output shaft, and includes an anti-rotation shaft that restricts tangential rotation of the input / output shaft.

9. The automatic pallet changing device according to claim 8, characterized in that the input / output shaft and the anti-rotation shaft are connected in parallel.

10. The automatic pallet changing device according to claim 8 or 9, characterized in that the input / output shaft and the anti-rotation shaft are arranged horizontally side by side.

Images