JP7152335B2 - Pallet overturn prevention mechanism and automatic pallet changer - Google Patents

Description

The present invention relates to an automatic pallet changer installed in a machine tool, and a pallet overturn prevention mechanism used to prevent overturning (including misalignment, tilting, falling, etc.) during transportation of a pallet, and the mechanism. and an automatic pallet changer.

2. Description of the Related Art Machine tools such as horizontal machining centers are equipped with an automatic pallet changer that changes pallets by vertically and horizontally turning a swivel arm on which pallets are placed on both ends. In this automatic pallet exchange device, the pallet exchange time is non-processing time, so the turning speed is increased as much as possible to shorten the pallet exchange time. However, since the pallet is only placed on the forks of the swivel arm by gravity, there is a risk that the pallet will be displaced or come off the forks if the balance between gravity and centrifugal force is lost. Therefore, the automatic pallet changer employs a mechanism for preventing the pallets from falling over. For example, Patent Document 1 discloses that an engaging member is protruding from the pallet exchange center side and gripped by a pair of upper and lower grip arms provided at the center side so that the pallet can be reliably positioned at the exchange position. An invention of a pallet gripping mechanism is disclosed. Further, in Patent Document 2, a locking member having a claw portion that is locked to a locking projection provided on a pallet is provided by a pressing pin in a locking direction to the locking projection, and a turning arm is provided. An operating rod that engages with the base so as to be interlocked with the lifting operation of the pallet to start or release locking of the pallet by the locking member, a locking member that locks the lifting of the operating rod, and a lifting operation of the turning arm. Disclosed is an invention of a pallet overturn prevention mechanism provided with an engaging operation member that engages with a base so as to interlock with the pallet.

Japanese Utility Model Laid-Open No. 4-5339 JP-A-2004-188543

The above conventional pallet overturn prevention mechanism is equipped with components that move vertically, such as a pair of grip arms, a locking member, and an operating rod. Adoption may be difficult for machine tools.
In particular, in the mechanism disclosed in Document 2, since the locking member engages and disengages the operating rod perpendicularly, a force in a direction oblique to the axial direction acts on the operating rod and the locking member. Therefore, if a slide bearing is used as a bearing for the operating rod or the locking member, there is a possibility that a force in an oblique direction may cause side contact and uneven wear. Furthermore, since the component parts are installed in a substantially exposed state, operability may be deteriorated due to entry of chips. It is conceivable to use an air purge to prevent chips from entering, but this will lead to an increase in cost, and the rotating arm will move up and down and rotate. It is difficult to supply air.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a pallet overturn prevention mechanism and an automatic pallet changer that can be constructed in a space-saving and low-cost manner and that are excellent in durability and dust resistance.

In order to achieve the above object, the invention according to claim 1 is provided with a turning arm having fork portions at both ends on a base, and is placed on the fork portion by horizontally turning and raising and lowering the turning arm. A pallet overturn prevention mechanism provided in an automatic pallet changer capable of exchanging pallets and engaging with the pallet when the turning arm horizontally turns to prevent the pallet from overturning,
an output shaft provided on the fork portion so as to move forward and backward in the axial direction and engageable with the pallet at an advanced position; a motion transmission portion provided on the fork portion so as to move forward and backward integrally with the output shaft; urging means provided on a fork portion for urging the output shaft to a forward position; an external cylinder having a piston rod movable between a protruded position to be pushed into position to disengage the output shaft from engaging the pallet and a retracted position away from the motion transmitting portion in the advanced position; characterized by comprising:
According to a second aspect of the invention, in the configuration of the first aspect, the motion transmitting portion is an input shaft connected to the output shaft.
The invention according to claim 3 is the configuration according to claim 2, wherein the output shaft, the input shaft, and the biasing means are mounted in a case provided on the lower surface side of the fork portion. and the protruding portion of the tip portion of the case is sealed with a dust seal, while the protruding portion of the piston rod of the outer cylinder is also sealed with a dust seal. Characterized by
According to a fourth aspect of the invention, in the configuration of the second or third aspect, the input shaft is connected in parallel with the output shaft.
According to a fifth aspect of the invention, in any one of the second to fourth aspects, the output shaft and the input shaft are vertically arranged side by side.
In order to achieve the above object, the invention according to claim 6 is provided with a rotating arm having fork portions at both ends on a base, and a pallet placed on the fork portion by rotating and raising and lowering the rotating arm. An automatic pallet changer capable of exchanging
A pallet overturn prevention mechanism according to any one of claims 1 to 5 is provided.

ADVANTAGE OF THE INVENTION According to this invention, a space-saving and low-cost pallet tipping prevention function is obtained. Also, unlocking of the pallet can be easily performed by the external cylinder. Furthermore, since the output shaft moves back and forth in the axial direction, uneven wear can be prevented even if a plain bearing is used as the bearing, and durability can be expected.
According to the second aspect of the invention, in addition to the above effect, since the motion transmitting portion is the 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 invention, in addition to the above effects, the protruding portions of the output shaft, the input shaft, and the piston rod are each sealed with dust seals. Malfunctions are less likely to occur.
According to the fourth aspect of the invention, in addition to the effects described above, since the input shaft and the output shaft are connected in parallel, the output shaft can be smoothly retracted, and the overall mechanism can be made compact. .
According to the fifth aspect of the invention, in addition to the above effects, the output shaft and the input shaft are vertically arranged side by side, so that the size is further reduced in the horizontal direction orthogonal to both shafts.

It is a perspective view of the automatic pallet changer seen from the setup station side. It is an expansion perspective view of a pallet fall prevention mechanism part. FIG. 4 is a cross-sectional view of the pallet overturn prevention mechanism portion (the pallet is in a locked state); FIG. 11 is a cross-sectional view of the pallet overturn prevention mechanism portion (the pallet is in an unlocked state);

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an automatic pallet changer 1 provided in a horizontal machining center from the setup station 2 side. The automatic pallet changer 1 is equipped with a swing arm 4 that horizontally swivels and moves up and down on a base 3 by a motor and a lifting mechanism (not shown). A pair of fork portions 5 (only one end side is shown in FIG. 1) for mounting and supporting the pallet 40 are provided at both ends of the swivel arm 4, respectively. A partition cover 6 is provided on the upper surface of the swivel arm 4 to partition the processing chamber and the setup station 2 .
Further, the automatic pallet changer 1 is provided with a pallet overturn prevention mechanism 10 to prevent the pallet 40 from being displaced or removed from the fork portion 5 when the swing arm 4 is horizontally turned when the pallet 40 is exchanged. there is As shown in FIG. 2, the pallet overturn prevention mechanism 10 includes a lock portion 11 provided on the fork portion 5 and a lock release portion 12 provided on the main body 7 of the setup station 2. As shown in FIG.

As shown in FIG. 3, a housing recess 8 is formed on the lower surface of the fork portion 5 on the inner edge side. A lock body 14 is provided. Note that the lock portion 11 will be described with the left side shown in FIG. 3 as the front side and the right side as the rear side.
The lock body 14 is formed by connecting the rear ends of two upper and lower round bar-shaped output shafts 15 and an input shaft 16 as a motion transmitting part in parallel with each other via an adapter 17 . The front end portion of the input shaft 16 penetrates the case 13 and protrudes from the front surface of the case 13 so as to move back and forth. The case 13 has a rear lid 18 which forms a space for allowing the forward and backward movement of the adapter 17, and a front lid 20 which abuts against a ring-shaped stopper 19 provided at the intermediate portion of the input shaft 16 to restrict the projecting position. is provided. The output shaft 15 and the input shaft 16 are supported in the case 13 by front and rear slide bearings 21, 21, respectively, and protruding portions of the front ends from the case 13 are sealed by dust seals 22, 22, respectively.

A large-diameter hole 23 through which the stopper 19 can move back and forth is formed in the housing portion of the input shaft 16 in the case 13 . A coil spring 24 is housed as an exterior biasing means. The coil spring 24 pushes the stopper 19 forward, so that the lock body 14 in the normal state is urged to the forward position where the stopper 19 contacts the front cover 20 . The lower surface of the pallet 40 is provided with an L-shaped hook 41 positioned in front of the output shaft 15 when placed on the fork portion 5 . The tip of shaft 15 engages with hook 41 . The pallet 40 is thereby fixed to the fork portion 5 .

On the other hand, in the unlocking portion 12 , the external cylinder 30 is horizontally supported on the main body 7 via the cylinder bracket 31 . Note that the unlocking portion 12 will be described with the right side shown in FIG. 3 as the front side and the left side as the rear side.
The external cylinder 30 has a piston 33 in which a piston rod 34 positioned on a coaxial extension line of the input shaft 16 of the lock portion 11 protrudes forward in a cylinder chamber 32 . Therefore, by supplying compressed air (or hydraulic pressure) to the cylinder chamber 32 before and after the piston 33, the piston 33 can be axially moved back and forth to move the piston rod 34 back and forth. A protruding portion of the piston rod 34 in the outer cylinder 30 is also sealed by a dust seal 35 . The outer cylinder 30 and the cylinder bracket 31 are covered with a cover 36 attached to the main body 7 from above, except for the projecting portion of the piston rod 34 . FIG. 3 shows the retracted position of the piston 33, in which the piston rod 34 is spaced from the input shaft 16 in the extended position. When the piston 33 advances, the piston rod 34 advances and comes into contact with the input shaft 16 as shown in FIG. As a result, the output shaft 15 is also pushed into the case 13 and disengaged from the hook 41 .

In the automatic pallet changer 1 constructed as described above, the piston 33 of the lock release portion 12 is positioned at the retracted position of the cylinder chamber 32 by air pressure as shown in FIG. The piston rod 34 is spaced apart 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 (the pallet 40 is locked) because the lock body 14 is at the projecting position (advance position).
When replacing the pallet 40 from here, even if the swing arm 4 rises and swings horizontally, the engagement of the output shaft 15 with the hook 41 is maintained, so the position of the pallet 40 shifts or tilts. No fear.

On the other hand, when the pallet 40 is to be removed at the setup station 2, the piston 33 of the unlocking portion 12 advances by air pressure to project the piston rod 34. As shown in FIG. Then, in the lock portion 11, the input shaft 16 and the lock body 14 are pushed into the case 13 together with the input shaft 16 as shown in FIG. Therefore, the pallet 40 can be removed from the fork portion 5 .
When the pallet 40 is placed again, the piston 33 is retracted and the piston rod 34 is retracted, so that the input shaft 16 and the lock body 14 are returned to the forward position by the force of the coil spring 24, so that the output shaft 15 is moved. It advances and engages 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 only in the axial direction between the output shaft 15 and the input shaft 16. 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 a direction oblique to the axial direction. Therefore, the slide bearing 21 is less likely to be hit. In addition, since the output shaft 15, the input shaft 16, and the protruding portions of the piston rod 34 are all sealed with the dust seals 22 and 35, the internal mechanism is not exposed, so the dust resistance can be maintained. Furthermore, 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 it is compact in the width direction and the height direction.

As described above, according to the pallet overturn prevention mechanism 10 and the automatic pallet changer 1 of the above-described configuration, the fork portion 5 is provided so as to move forward and backward in the axial direction, and the output is capable of engaging the hook 41 of the pallet 40 at the forward position. a shaft 15; an input shaft 16 provided on the fork portion 5 so as to move forward and backward integrally with the output shaft 15; a coil spring 24 provided on the fork portion 5 and biasing the output shaft 15 toward the forward position; a projecting position provided at a position forward of the input shaft 16 in the lowered state and pushing the input shaft 16 from the forward position to the retracted position to release the engagement of the output shaft 15 with the hook 41 of the pallet 40; and an external cylinder 30 with a piston rod 34 movable between a retracted position spaced from the input shaft 16 to provide space-saving and low-cost pallet tipover protection. Further, unlocking of the pallet 40 can be easily performed by the external cylinder 30. - 特許庁Furthermore, 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 employed, and durability can be expected.

In particular, since the input shaft 16 connected to the output shaft 15 is used as the motion transmitting portion to the output shaft 15, the piston rod 34 can reliably push the output shaft 15. As shown in FIG.
In addition, the output shaft 15, the input shaft 16, and the coil spring 24 are housed in a case 13 provided on the lower surface side of the fork portion 5, except for the distal end portions of the output shaft 15 and the input shaft 16. The protruding portion of the tip is sealed by the dust seal 22, while the protruding portion of the piston rod 34 in the outer cylinder 30 is also sealed by the dust seal 35, so that high dust resistance can be obtained, and operation due to intrusion of chips and the like can be achieved. Defects are less likely to occur.
Furthermore, since the input shaft 16 is connected in parallel with the output shaft 15, the output shaft 15 can be smoothly retracted, and the overall mechanism can be made compact.
In addition, since the output shaft 15 and the input shaft 16 are vertically arranged side by side, it becomes more compact in the horizontal direction perpendicular to both shafts.

In addition, in the lock portion, the structure of the output shaft and the input shaft is not limited to the above-described form, and may be a square bar shape instead of a round bar shape or a plate shape. The connecting structure of both shafts can also be changed as appropriate, and the end of one shaft can be bent into an L shape and connected to the other shaft. It is also possible to arrange both axes horizontally to the left and right instead of arranging them vertically, and it is also possible to change the structure with both axes. The coil spring may also be provided on the output shaft instead of the input shaft, or may be provided on both shafts.
Further, the motion transmitting portion is not limited to the input shaft parallel to the output shaft, and a ridge projecting radially outward from the output shaft may be employed.
The pallet side is not limited to hooks, and a projecting piece provided downward from the bottom surface of the pallet may be provided with a through hole or a bottomed hole for inserting or removing the output shaft, or a through hole or a 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 at the unlocking portion as well as the output shaft. In addition, depending on the space below the swivel arm, the cover may be omitted, and an external cylinder may be installed in a recess formed in the main body of the setup station to press the motion transmitting portion similarly located in the recess. can.

DESCRIPTION OF SYMBOLS 1... Automatic pallet changer, 2... Setup station, 3... Base, 4... Rotating arm, 5... Fork part, 7... Main body, 8... Concave part, 10... Pallet tipping prevention mechanism , 11... lock portion, 12... unlock portion, 13... case, 14... lock body, 15... output shaft, 16... input shaft, 17... adapter, 19... stopper, 21... Slide bearing 22, 35 Dust seal 24 Coil spring 30 External cylinder 33 Piston 34 Piston rod 40 Pallet 41 Hook.

Claims (6)

Provided in an automatic pallet changer having a swivel arm having fork parts at both ends on a base and capable of replacing a pallet placed on the fork part by horizontal swivel and vertical movement of the swivel arm, the swivel arm A pallet overturn prevention mechanism for preventing overturning of the pallet by engaging with the pallet when the is horizontally turning,
an output shaft provided on the fork portion so as to move forward and backward in the axial direction and engageable with the pallet at the forward position;
a motion transmitting portion provided on the fork portion so as to move forward and backward integrally with the output shaft;
biasing means provided on the fork portion and biasing the output shaft to a forward position;
a protruding position provided at a position forward of the motion transmitting portion in the lowered state of the swing arm, the protruding position pushing the motion transmitting portion from the forward position to the retracted position to release the engagement of the output shaft with the pallet; an external cylinder with a piston rod movable between a retracted position spaced apart from the motion transmitting portion in an advanced position;
A pallet overturn prevention mechanism, comprising: 2. The pallet overturn prevention mechanism according to claim 1, wherein the motion transmission part is an input shaft connected to the output shaft. The output shaft, the input shaft, and the biasing means are housed in a case provided on the lower surface side of the fork portion, except for tip end portions of the output shaft and the input shaft. While the protruding portion of the tip is sealed with a dust seal,
3. The pallet overturn prevention mechanism according to claim 2, wherein the projecting portion of said piston rod in said outer cylinder is also sealed by a dust seal. 4. A pallet overturn prevention mechanism according to claim 2, wherein said input shaft is connected in parallel with said output shaft. 5. The pallet overturn prevention mechanism according to claim 2, wherein the output shaft and the input shaft are vertically arranged side by side. An automatic pallet changer which is provided on a base with a swivel arm having fork parts at both ends, and which can replace a pallet placed on the fork part by horizontally swiveling and lifting the swivel arm,
An automatic pallet changer comprising the pallet overturn prevention mechanism according to any one of claims 1 to 5.

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