JP2020151832A - Pallette fall prevention mechanism and automatic pallette exchange device - Google Patents

Abstract

To provide a pallette fall prevention mechanism and an automatic pallette exchange device that can be constituted with a space saved and at low costs and have excellent durability and dust resistance.SOLUTION: A pallette fall prevention mechanism 10 provided in an automatic pallette exchange device 1 is configured to include: an output shaft 15, provided in a fork part 5 to be movable back and forth in a shaft direction, which can engage with a hook 41 of a pallette 40 at a forward movement position; an input shaft 16 provided in the fork part 5 to be movable back and forth parallely and integrally with the output shaft 15; a coil spring 24, provided in the fork part 5, which energizes the output shaft 15 to the forward movement position; and an external cylinder 30 comprising a piston rod 34, provided at a position on an extended line of the input shaft 16 with a turning arm 4 descended, which can move between a protrusion position where the input shaft 16 is pressed from the forward movement position into a backward movement position so that engagement of the pallette 40 with the hook 41 by the output shaft 15 is released and a backward movement position where the rod separates from the input shaft 16 at the forward movement position.SELECTED DRAWING: Figure 3

Description

The present invention uses a pallet tipping prevention mechanism used to prevent a tipping (including misalignment, tilting, dropping, etc.) when transporting a pallet in an automatic pallet changing device provided in a machine tool, and the mechanism. Regarding the automatic pallet changing device that was there.

Machine tools such as horizontal machining centers are provided with an automatic pallet changing device that changes pallets by raising and lowering and horizontally turning pallets on both ends. In this automatic pallet changing device, the pallet changing time is the non-processing time, so the turning speed is increased as much as possible with the aim of shortening the time. However, since the pallet is only placed on the fork portion of the swivel arm by gravity, if the balance between gravity and centrifugal force is lost, the pallet may be displaced or come off from the fork portion. Therefore, the automatic pallet changing device employs a mechanism for preventing the pallet from tipping over. For example, Patent Document 1 states that the pallet can be reliably positioned at the replacement position by projecting the engaging member on the replacement center side of the pallet and gripping the engaging member by a pair of upper and lower grip arms provided on the center side. The invention of the pallet gripping mechanism is disclosed. Further, in Patent Document 2, a locking member having a claw portion for locking to the locking protrusion provided on the pallet is provided by urging the locking protrusion in the locking direction by a pressing pin, and a swivel arm is provided. The operation rod that starts or releases the pallet locking by the locking member by engaging with the base so as to be interlocked with the elevating operation of the operating rod, the locking member that locks the ascending of the operating rod, and the elevating operation of the swivel arm The invention of a pallet fall prevention mechanism including an engaging operation member for engaging operation with a base so as to interlock with the above is disclosed.

Jikkenhei No. 4-5339 Japanese Unexamined Patent Publication No. 2004-188543

Since the conventional pallet fall prevention mechanism includes a pair of grip arms, locking members, operating rods, and other components that operate in the vertical direction, it is necessary to secure a large storage space under the swivel arm, resulting in a small size. It may be difficult to adopt with machine tools.
Further, in particular, in the mechanism of Cited Document 2, since the lock member engages and disengages orthogonally to the operation rod, a force acts on the operation rod and the lock member in an oblique direction with respect to the axial direction. Therefore, if a slide bearing is used as the bearing of the operating rod or the lock member, it may be hit by a force in the oblique direction and uneven wear may occur. Further, since the components are installed in a substantially exposed state, the operability may be deteriorated due to the intrusion of chips. It is conceivable to use an air purge to prevent chips from entering, but this will lead to cost increase, and since the swivel arm involves vertical and swivel movements, connect the piping to the pallet fall prevention mechanism to follow this. It is difficult to supply air.

Therefore, an object of the present invention is to provide a pallet tipping prevention mechanism and an automatic pallet changing device which can be configured in a space-saving manner and at low cost and have excellent durability and dust resistance.

In order to achieve the above object, the invention according to claim 1 is provided with a swivel arm having fork portions at both ends on a base, and is placed on the fork portion by horizontal swivel and elevating operation of the swivel arm. A pallet tipping prevention mechanism provided in an automatic pallet changing device that allows the pallet to be replaced, and is provided to prevent the pallet from tipping over by engaging with the pallet when the swivel arm makes a horizontal turn.
An output shaft provided on the fork portion so as to be able to move forward and backward in the axial direction and engageable with the pallet at a forward position, and an operation transmission portion provided on the fork portion so as to be able to move forward and backward integrally with the output shaft. An urging means provided on the fork portion to urge the output shaft to the forward position, and a position provided in front of the motion transmission portion in the lowered state of the swivel arm to retract the motion transmission portion from the forward position. An external cylinder provided with a piston rod that can move between a protruding position that is pushed into a position to disengage the output shaft from engaging with the pallet and a retracted position that is separated from the motion transmitting portion in the forward position. It is characterized by including.
The invention according to claim 2 is characterized in that, in the configuration of claim 1, the motion transmitting unit is an input shaft connected to the output shaft.
According to a third aspect of the present invention, in the configuration of the second aspect, the output shaft, the input shaft, and the urging means are provided in a case provided on the lower surface side of the fork portion, and the output shaft and the input shaft are provided in a case. The protruding portion of the tip portion in the case is sealed by a dust seal, while the protruding portion of the piston rod in the external cylinder is also sealed by the dust seal. It is a feature.
The invention according to claim 4 is characterized in that, in the configuration of claim 2 or 3, the input shaft is connected in parallel with the output shaft.
The invention according to claim 5 is characterized in that, in any of the configurations of claims 2 to 4, the output shaft and the input shaft are arranged vertically.
In order to achieve the above object, the invention according to claim 6 is provided with a swivel arm having fork portions at both ends on a base, and the pallet is placed on the fork portion by swiveling and raising and lowering the swivel arm. It is an automatic pallet exchange device that makes it possible to exchange
The pallet fall prevention mechanism according to any one of claims 1 to 5 is provided.

According to the present invention, a pallet tipping prevention function can be obtained at low space and low cost. In addition, the pallet can be easily unlocked by using an external cylinder. Further, since the output shaft moves forward and backward in the axial direction, uneven wear can be prevented even if a slide bearing is used for the bearing, and durability can be expected.
According to the second aspect of the present invention, in addition to the above effects, since the motion transmission unit is an input shaft connected to the output shaft, the output shaft can be reliably pushed by the piston rod.
According to the third aspect of the present invention, in addition to the above effects, the output shaft, the input shaft, and the protruding portion of the piston rod are each sealed with a dust seal, so that high dust resistance can be obtained and due to the intrusion of chips and the like. Malfunctions are less likely to occur.
According to the invention of claim 4, in addition to the above effects, since the input shaft is connected in parallel with the output shaft, the output shaft can be smoothly retracted and the entire mechanism can be made compact. ..
According to the fifth aspect of the present invention, in addition to the above effects, since the output shaft and the input shaft are arranged vertically, the shaft becomes more compact in the horizontal direction orthogonal to both shafts.

It is a perspective view of the automatic pallet exchange device seen from the setup station side. It is an enlarged perspective view of the pallet fall prevention mechanism part. It is sectional drawing (the pallet is locked state) of the pallet fall prevention mechanism part. It is a cross-sectional view of the pallet fall prevention mechanism part (the pallet is in the unlocked state).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows the automatic pallet changing device 1 provided in the horizontal machining center from the setup station 2 side. The automatic pallet changing device 1 includes a swivel arm 4 that horizontally swivels and lifts and lowers on the base 3 by a motor and an elevating mechanism (not shown), and the swivel arm 4 replaces the pallet 40 between the processing chamber and the setup station 2. A pair of fork portions 5 (only one end side is shown in FIG. 1) on which the pallet 40 is placed and supported are provided at both ends of the swivel arm 4. A partition cover 6 for partitioning the processing chamber and the setup station 2 is provided on the upper surface of the swivel arm 4.
Further, the automatic pallet changing device 1 is provided with a pallet tipping prevention mechanism 10 so that the pallet 40 does not shift or come off from the fork portion 5 when the swivel arm 4 is horizontally swiveled when the pallet 40 is replaced. There is. As shown in FIG. 2, the pallet fall prevention mechanism 10 includes a lock portion 11 provided on the fork portion 5 and an unlock portion 12 provided on the main body 7 of the setup station 2.

As shown in FIG. 3, a storage recess 8 is formed on the lower surface of the fork portion 5 and on the inner edge side, and the lock portion 11 is housed in a case 13 attached to the storage recess 8 and the case 13. It has a lock body 14. In the lock portion 11, the left side shown in FIG. 3 will be described as the front and the right side will be described as the rear.
The lock body 14 is formed by connecting the rear ends of the two upper and lower round bar-shaped output shafts 15 and the input shaft 16 as the motion transmission unit in parallel with each other via the adapter 17, and the lock body 14 and the output shaft 15 The front end portion of the input shaft 16 is housed so as to be able to move forward and backward in a state of penetrating the case 13 and projecting from the front surface thereof. The case 13 has a rear lid 18 that forms a space that allows the adapter 17 to move forward and backward, and a front lid 20 that comes into contact with a ring-shaped stopper 19 provided in the middle of the input shaft 16 to regulate the protruding position. It is provided. The output shaft 15 and the input shaft 16 are pivotally supported by the front and rear slide bearings 21 and 21 in the case 13, and the protruding portion of the front end portion from the case 13 is sealed by the dust seals 22 and 22, respectively.

Further, in the case 13, a large-diameter hole 23 through which the stopper 19 can move forward and backward is formed in the accommodating portion of the input shaft 16, and the input shaft 16 is formed in the large-diameter hole 23 behind the stopper 19. A coil spring 24 as an exterior urging means is housed. When the coil spring 24 presses the stopper 19 forward, the lock body 14 in the normal state is urged to the forward position where the stopper 19 abuts on the front lid 20. An L-shaped hook 41 located in front of the output shaft 15 when mounted on the fork portion 5 is provided on the lower surface of the pallet 40, and the output protruding from the case 13 is provided at the forward position of the lock body 14. The tip of the shaft 15 engages with the hook 41. As a result, the pallet 40 is fixed to the fork portion 5.

On the other hand, in the unlocked portion 12, the external cylinder 30 is horizontally supported on the main body 7 via the cylinder bracket 31. In the unlocking unit 12, the right side shown in FIG. 3 will be described as the front and the left side will be described as the rear.
The external cylinder 30 has a piston 33 in the cylinder chamber 32 in which a piston rod 34 located on a coaxial extension line of the input shaft 16 of the lock portion 11 is projected forward. Therefore, by supplying compressed air (which may be hydraulic pressure) to the cylinder chamber 32 before and after the piston 33, the piston 33 can be moved forward and backward in the axial direction to move the piston rod 34 forward and backward. The protruding portion of the piston rod 34 in the external cylinder 30 is also sealed by the dust seal 35. Further, the external cylinder 30 and the cylinder bracket 31 are covered with a cover 36 attached to the main body 7 from above, except for the protruding portion of the piston rod 34. FIG. 3 shows the retracted position of the piston 33, at which the piston rod 34 is separated from the input shaft 16 at the protruding position. When the piston 33 advances, as shown in FIG. 4, the piston rod 34 advances and comes into contact with the input shaft 16, and the lock body 14 is pushed into the case 13 together with the input shaft 16 as it is. As a result, the output shaft 15 is also pushed into the case 13 and the engagement with the hook 41 is released.

In the automatic pallet changing device 1 configured as described above, in the pallet tipping prevention mechanism 10 in the normal state, the piston 33 of the unlocking portion 12 is positioned at the retracted position of the cylinder chamber 32 by pneumatic pressure as shown in FIG. The piston rod 34 is separated from the input shaft 16. Therefore, in the lock portion 11, the tip of the output shaft 15 is engaged with the hook 41 of the pallet 40 because the lock body 14 is in the protruding position (advance position) (the pallet 40 is locked).
When replacing the pallet 40 from here, even if the swivel arm 4 rises and turns horizontally, the engagement of the output shaft 15 with the hook 41 is maintained, so that the pallet 40 is displaced or tilted. There is no fear.

On the other hand, when the pallet 40 is removed at the setup station 2, the piston 33 of the unlocking portion 12 advances by air pressure to project the piston rod 34. Then, in the lock portion 11, the output shaft 15 is disengaged from the hook 41 by pushing the lock body 14 into the case 13 together with the input shaft 16 as shown in FIG. 4 (unlocked state of the pallet 40). Therefore, the pallet 40 can be removed from the fork portion 5.
When the pallet 40 is placed again, if the piston 33 is retracted and the piston rod 34 is retracted, the lock body 14 returns to the forward position by the bias of the coil spring 24 together with the input shaft 16, so that the output shaft 15 is moved. It moves forward and engages with the hook 41 to fix the pallet 40.

Here, the piston rod 34 abuts or separates from the input shaft 16 in the axial direction in both the locked state and the unlocked state of the pallet 40, and the output shaft 15 and the input shaft 16 are brought into contact with each other only in the axial direction. Since it is moved back and forth, no external force is applied to the output shaft 15, the input shaft 16, and the coil spring 24 in an oblique direction with respect to the axial direction. Therefore, the slide bearing 21 is less likely to be hit. Further, the output shaft 15, the input shaft 16, and the protruding portion of the piston rod 34 are all sealed with dust seals 22 and 35, and the internal mechanism is not exposed, so that dust resistance can be maintained. Further, in the lock portion 11 on the swivel arm 4 side, it is sufficient to arrange the two output shafts 15 and the input shaft 16 horizontally, so that the lock portion 11 becomes compact in the width direction and the height direction.

As described above, according to the pallet tipping prevention mechanism 10 and the automatic pallet changing device 1 of the above-described embodiment, the fork portion 5 is provided so as to be able to move forward and backward in the axial direction, and the output can be engaged with the hook 41 of the pallet 40 at the forward position. The shaft 15, the input shaft 16 provided on the fork portion 5 so as to be able to move forward and backward integrally with the output shaft 15, the coil spring 24 provided on the fork portion 5 to urge the output shaft 15 to the forward position, and the swivel arm 4. A protruding position and a forward position, which are provided at a position in front of the input shaft 16 in the lowered state and push the input shaft 16 from the forward position to the backward position to disengage the pallet 40 from engaging with the hook 41 by the output shaft 15. By including an external cylinder 30 provided with a piston rod 34 that can move between the retracted position separated from the input shaft 16, the pallet tipping prevention function can be obtained at low space and low cost. Further, the lock of the pallet 40 can be easily unlocked by the external cylinder 30. Further, since the output shaft 15 and the input shaft 16 move forward and backward in the axial direction, uneven wear can be prevented even if the slide bearing 21 is adopted, and durability can be expected.

In particular, here, since the motion transmission unit to the output shaft 15 is the input shaft 16 connected to the output shaft 15, the output shaft 15 can be reliably pushed by the piston rod 34.
Further, the output shaft 15, the input shaft 16, and the coil spring 24 are housed in the case 13 provided on the lower surface side of the fork portion 5, except for the tip portions of the output shaft 15 and the input shaft 16, and in the case 13. While the protruding portion of the tip portion is sealed by the dust seal 22, the protruding portion of the piston rod 34 in the external cylinder 30 is also sealed by the dust seal 35, so that high dust resistance can be obtained and the operation due to the intrusion of chips and the like can be obtained. Defects are less likely to occur.
Further, since the input shaft 16 is connected in parallel with the output shaft 15, the output shaft 15 can be smoothly retracted, and the entire mechanism can be made compact.
In addition, since the output shaft 15 and the input shaft 16 are arranged vertically, the output shaft 15 and the input shaft 16 become more compact in the horizontal direction orthogonal to both axes.

In the lock portion, the structure of the output shaft and the input shaft is not limited to the above-mentioned form, and may be a square bar shape or a plate shape instead of a round bar shape. The connecting structure of both shafts can be changed as appropriate, and the end of one shaft can be bent into an L shape to be connected to the other shaft. It is possible to arrange both axes horizontally instead of vertically, and the structure can be changed on both axes. The coil spring may be provided on the output shaft instead of the input shaft, or may be provided on both shafts, respectively, or an urging means such as a coil spring may be provided behind the adapter to urge the entire lock body.
Further, the motion transmission unit is not limited to the input shaft parallel to the output shaft, and a ridge or the like protruding radially outward from the output shaft can be adopted.
The pallet side is not limited to the hook, but the projecting piece provided downward from the lower surface of the pallet may be provided with a through hole or a bottomed hole through which the output shaft can be inserted / removed, or the through hole or the bottomed hole provided in the pallet itself. The output shaft may be directly inserted and removed.
The shape of the piston rod can be changed in the unlocked portion as well as the output shaft. In addition, the cover may be omitted, or depending on the space below the swivel arm, an external cylinder may be installed in the recessed recess in the main body of the setup station to press the motion transmission unit also located in the recess. it can.

1 ... Automatic pallet changer, 2 ... Setup station, 3 ... Base, 4 ... Swivel arm, 5 ... Fork, 7 ... Main body, 8 ... Storage recess, 10 ... Pallet fall prevention mechanism , 11 ... Lock part, 12 ... Unlock part, 13 ... Case, 14 ... Lock body, 15 ... Output shaft, 16 ... Input shaft, 17 ... Adapter, 19 ... Stopper, 21 ... Plain bearings, 22, 35 ... dust seals, 24 ... coil springs, 30 ... external cylinders, 33 ... pistons, 34 ... piston rods, 40 ... pallets, 41 ... hooks.

Claims (6)

A swivel arm having forks at both ends is provided on a base, and the swivel arm is provided in an automatic pallet changing device capable of replacing a pallet mounted on the fork by horizontal turning and raising / lowering of the swivel arm. Is a pallet tipping prevention mechanism for preventing the pallet from tipping over by engaging with the pallet when turning horizontally.
An output shaft provided on the fork portion so as to be able to move forward and backward in the axial direction and engage with the pallet at the forward position,
An operation transmission unit provided on the fork unit so as to be able to move forward and backward integrally with the output shaft,
An urging means provided on the fork portion to urge the output shaft to the forward position,
A protruding position provided at a position in front of the motion transmitting portion in the lowered state of the swivel arm and pushing the motion transmitting portion from the forward position to the retracting position to release the engagement of the output shaft with the pallet. An external cylinder with a piston rod that can move between the forward position and the retracted position that is separated from the motion transmission section.
A pallet fall prevention mechanism characterized by containing. The pallet fall prevention mechanism according to claim 1, wherein the motion transmission unit is an input shaft connected to the output shaft. The output shaft, the input shaft, and the urging means are housed in a case provided on the lower surface side of the fork portion, except for the output shaft and the tip portion of the input shaft, and the said in the case. While the protruding part of the tip is sealed by a dust seal,
The pallet fall prevention mechanism according to claim 2, wherein the protruding portion of the piston rod in the external cylinder is also sealed by a dust seal. The pallet fall prevention mechanism according to claim 2 or 3, wherein the input shaft is connected in parallel with the output shaft. The pallet tipping prevention mechanism according to any one of claims 2 to 4, wherein the output shaft and the input shaft are arranged vertically. An automatic pallet changing device in which a swivel arm having fork portions at both ends is provided on a base, and the pallet placed on the fork portion can be replaced by horizontal swiveling and raising / lowering operation of the swivel arm.
An automatic pallet changing device comprising the pallet fall prevention mechanism according to any one of claims 1 to 5.

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