JPH0512096B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Industrial Application Field The present invention relates to a pallet changer used in automatic machine tools such as NC processing machines to change pallets on which workpieces are placed. relates to a pallet locking device for holding pallets on a pallet stand.

(b) Prior Art Conventionally, a pallet changer has a pallet stand that holds a large number of pallets, and the pallets are transferred between the stand and a processing machine side table. The pallet is then clamped on the processing machine table by fitting the T-shaped groove formed at the bottom of the pallet into a fixing plate and pulling the plate downward with a hydraulic cylinder. In this method, a hydraulic cylinder is used to install a pin that projects in the vertical direction, and the pin is engaged with a hole formed in the lower surface of the pallet on which the workpiece is placed, thereby mounting the pallet. Further, the pallet has a T-shaped groove portion (clamp portion) having a rectangular outer contour so as to fit into the T-shaped groove.

(c) Problems to be solved by the invention For this reason, in order to rotate the pallets, it was necessary to install a rotation mechanism composed of bearings, etc. on the pallet stand side, making the structure complicated. In addition, when transferring a pallet from the processing machine table to the pallet stand, or conversely from the pallet stand to the processing machine table, it is necessary to position the pallet accurately.
The pallet transfer speed is limited, which reduces processing efficiency, and it is necessary to finish the pins of the pallet stand and the pin holes of the pallet with high precision, which causes an increase in costs.

Also, a pallet stand is known in which a U-shaped pallet holding recess is formed in the pallet stand so that the pallet can be rotated. In order to prevent the pallet from falling out of the recess, it is necessary to provide a stopper, but with a simple spring-type stopper, when the pallet is stored in the recess, there is a risk that the pallet will fall out of the recess due to slight vibration or shock. Yes, it is extremely dangerous. However, if a hydraulic stopper is provided, there is a risk of it falling off when the supply of pressure oil is stopped due to a power outage, etc., and some kind of countermeasure has been desired.

In addition, when trying to transport a pallet using a pallet stand, the stopper can securely hold the pallet, but it can also be easily released from the holding state without requiring any action from the processing machine. Structure is desirable.

(d) Means for Solving the Problem The present invention aims to solve the above-mentioned problems, and provides a pallet changer that transfers pallets between a processing machine side table and a pallet stand. The outer shell of the clamp part is configured in a circular shape, and the pallet holding recess of the pallet stand is configured in a U-shape consisting of a curved part and a straight part so that the outer shell of the clamp part can be freely inserted and engaged. A hydraulic cylinder device is provided on the stand so that the piston can be freely driven to protrude, a stopper is provided on the piston so that the piston can be driven to protrude into the recess from the straight portion, and the hydraulic cylinder device includes: The stopper may be held in a protruding state in such a manner that the piston block is engaged with the piston from a direction perpendicular to the direction of movement of the piston by means of elastic means to prevent movement of the piston due to the shape of the piston block. The piston block is mounted on the piston block by hydraulic pressure.
A block driving means is provided which is driven so as to be released from the engagement state with the piston against the elastic means, and pressurized oil is provided between the block driving means and the hydraulic supply path of the hydraulic cylinder on the side where the piston retreats. It is constructed by providing a pressure oil supply means capable of simultaneously supplying.

(e) Effect Based on the above-mentioned means, the pallet stand is brought close to the processing machine side table, the pallet placed on the processing machine side table is directly received into the recessed part of the pallet stand, and the stopper is held by the hydraulic cylinder device. The stopper protrudes and comes into contact with the outer shell of the circular clamp part, and in this state, the stopper is held in the protruding state by the piston block to reliably prevent the pallet from coming out of the recess, and in this state, the pallet stand is returned to the specified position. Transfer the pallet to the stand. Further, the pallet held on the stand is easily rotated on the stand because the circular clamp portion of the pallet is held in the U-shaped recess and only prevented from coming off by the stopper.

Further, when the stopper is released, pressure oil is supplied to the hydraulic pressure supply path so that the locking state of the stopper by the piston block is released and the stopper is moved in and out at the same time.

(f) Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The pallet changer 1 has a pallet stand 2, as shown in FIG. It can reciprocate. Further, the processing machine table 6 can move in the left and right direction, and a clamp device and a positioning set pin are provided below the table 6, and the clamp device fits into a T-shaped groove formed on the bottom surface of the pallet, which will be described later. - The pallet 7 can be fixed on the table 6 by clamping. On the other hand, the pallet stand 2 has two U-shaped recesses 9, 9.
is formed, and the recess 9 can hold the pallet 7. In the figure, reference numeral 10 denotes a workpiece mounted and fixed on the pallet 7, and 11 a cutter for processing the workpiece, which is rotated by a shaft 12 extending from the main body of the processing machine.

As shown in FIGS. 3 and 4, the pallet 7 is placed between the workpiece placement section 13 and the clamp section 1.
4, and the mounting part 13 has a rectangular shape with notched corners, and a large number of T-shaped grooves for fixing the workpiece 11 are formed on the upper surface thereof.
Further, the clamp portion 14 has a circular outer contour, and a T-shaped groove 15 for clamping is formed so as to pass along the diameter of the circle. In the figure, reference numerals 18 and 18 are holes into which positioning set pins are fitted.

Further, as shown in FIG. 1, a pallet locking device 16 is provided on the back side of the pallet stand 2, and the locking device 16 includes a hydraulic cylinder device 17 for preventing the pallet from coming off, and a hydraulic cylinder device 17 that moves the cylinder device to the protruding position. It consists of a safety protection device 19 that is held in place.
The hydraulic cylinder device 17 has a cylinder block 20 and a piston 21. A roller follower 22 is rotatably supported at one end of the piston 21, and a dock 23 is fixed.
The roller follower 22 protrudes into the recess from the side surface of the pallet holding recess 9 of the stand 2, that is, the straight part 9a of the U-shaped recess consisting of the curved part 9b and the straight part 9a, and the pallet clamp held in the recess 9. The dot 23 is placed at a position where it can come into contact with one side of the portion 14 to constitute a stopper, and the dot 23 can also come into contact with a limit switch 25 to detect the forward and backward positions of the piston 21. On the other hand, the safety protection device 19 has a cylinder block 26 and a piston 27 that can move forward and backward in a direction perpendicular to the moving direction of the piston 21 of the hydraulic cylinder device 17, and the piston 27 has a spring 30 between it and the cylinder head 29. The other end of the hydraulic cylinder device piston 21 is urged to come into contact with the end surface of the small diameter portion 21a and to control the movement of the piston 21 by utilizing the shape of the piston 27 itself. . Oil pipes 31 and 32 are connected to both cylinder chambers of the hydraulic cylinder device 17, respectively, and these oil pipes communicate with a hydraulic pump 35 via an electromagnetic switching valve 33. Further, the cylinder block 26 of the safety protection device 19 is provided with a spring 30 that retracts the piston 27, that is, the piston 27 is
A cylinder chamber is formed in the direction in which the piston 21 moves against the pressure and releases the arm of the piston 21, and the cylinder chamber communicates with the oil pipe 32 in the direction of entering and leaving the hydraulic cylinder device 17 via the oil pipe 36. There is. In addition,
In the figure, 37 is an oil tank, and 39 is a filter.

Since this embodiment has the above configuration, in order to transfer the pallet 7 from the processing machine table 6 to the pallet stand 2, first move the table 6 to a position where the pallet 7 is aligned with the recess 9 of the stand 2. Then, the clamping device is released to release the pallet 7 from the table 6 and lift it slightly. In this state, the pallet stand 2 is brought close to the table 6 by the reciprocating drive device 3, and the U-shaped recess 9 is fitted into the circular clamp portion 14 of the pallet 7. At this time, the switching valve 33 is operated to supply pressure oil from the pump 35 to the oil pipes 32 and 36, and the piston 27 of the safety protection device 19 is moved in and out, and the piston 21 of the hydraulic cylinder device 17 is moved in and out. , the roller follower 22 is attached to the concave side surface 9
Hold it in a position where it is recessed from a. When the pallet clamp part 14 is completely inserted into the curved part 9b in the recess 9 without being obstructed by the roller follower 22, the switching valve 33 is switched and the oil pipe 3
1 is supplied with pressure oil from a pump 35, and oil pipes 32 and 36 are drained to a tank 37. Then, the piston 21 of the hydraulic cylinder device 17
The roller follower 22 is moved to the right in the figure to protrude from the straight part 9a of the recess, and the safety protection device 1
The piston 27 of No. 9 is moved upward in FIG. 1 by the spring 30 and comes into contact with the end surface of the piston small diameter portion 21a, thereby controlling the movement of the piston 21. In this state, the pallet 7 is held in the concave portion 9 with the roller follower 22 in contact with one side facing outward from the center portion of the clamp portion 14, and is held in place in the reciprocating portion 9. When the stand 2 is moved in the direction away from the table 6 by the device 3, the pallet 7 leaves the table 6 while being held by the stand 2, whereby the pallet 7 is transferred from the table 6 to the stand 2 and held there.
In addition, in this state, the roller follower 22 is simply in contact with the outer surface of the circular pallet clamp part, so the pallet 7 can freely rotate within the recess 9, preparing for the next machining or changing the machining state. For inspection, the pallet 7 can be rotated manually or automatically to a predetermined rotational position.

When the pallet 7 is held on the stand 2, even if the power is turned off and the switching valve 33 is returned to the neutral position, the hydraulic cylinder device is The piston 21 of 17 is held at the protruding position, and the pallet 7 is reliably held and prevented from coming off by the stand 2.

That is, even in the event of a power outage, the piston 27 is maintained engaged with the piston 21 by the spring 30 that urges the piston 27 in a direction perpendicular to the direction of movement of the piston. 21 is prevented from moving by utilizing the shape of the piston 27, so even if a force acts on the piston 21 and the roller follower 22 to move the roller follower 22 back and forth, the force will not move. There is no action on the spring 30, and the roller follower 22 is reliably maintained in its protruding state.

Furthermore, in order to transfer the pallet 7 from the pallet stand 2 to the processing machine table 6, move the stand 2 close to the table 6, and when the pallet 7 reaches a predetermined position on the table 6, The fixing plate installed on the table 6 is lifted and the pins are fitted into the holes 18, 18 of the pallet 7 to position the pallet 7 at a predetermined position on the table 6. In this state, the switching valve 33 is switched, pressure oil is supplied to the oil pipes 32 and 36, and the piston 2
7 and 21 are retracted, the roller follower 22 is retracted to release the pallet 7 from coming off, and the stand 2 is moved back so as to pull out the pallet 7 from the recess 9. Thereafter, the clamping device is operated to fix the pallet 7 to the table 6 using the T-shaped groove 15 of the pallet 7, thereby transferring the pallet 7 from the stand 2 to the table 6 and fixing it.

(g) Effect of the Invention As explained above, according to the present invention, the pallet 7 is placed between the processing machine side table 6 and the pallet stand 2.
In the pallet changer 1 for transferring pallets between pallets, the outer shell of the pallet clamping part 14 is configured in a circular shape, and the outer shell of the clamping part can be freely inserted into and engaged with the pallet holding recess 9 of the pallet stand. , is configured in a U-shape consisting of a curved part 9b and a straight part 9a, and further includes a pallet stand,
A hydraulic cylinder device 17 is provided so that a piston 21 can be freely driven to protrude, and a stopper such as a roller follower 22 is provided on the piston so that it can be protruded from the straight part into the recessed part by the protruding drive of the piston. , the piston block such as the piston 27 is connected to the spring 3.
The stopper can be held in a protruding state by engaging the piston from a direction intersecting the moving direction of the piston by means of elastic means such as 0, and preventing movement of the piston by the shape of the piston block. The piston block is provided with a block driving means such as a cylinder block 26 for hydraulically driving the piston block so as to be able to release the engagement state with the piston against the elastic means. Since the pallet 7 is constructed by providing pressure oil supply means such as oil pipes 36 and 32 and an electromagnetic switching valve 33 that can simultaneously supply pressure oil to the drive means and the hydraulic supply path on the side where the piston of the hydraulic cylinder retreats. It can be freely rotated while being held on the stand 2, and the processing status of the workpiece 11 fixed on the pallet 7 can be easily inspected.
The pallet 7 can also be rotated in a predetermined direction in preparation for the next processing, thereby improving processing efficiency. In addition, since it is sufficient to provide the pallet stand 2 with a stopper 22 that can protrude into the recess 9 using a hydraulic cylinder device, there is no need to install a high-precision member on the stand 2 side as in the conventional case, and the pallet changer 1 can be greatly simplified. Furthermore, when transferring the pallet 7 from the processing machine side table 6 to the pallet stand 2, there is no need for accurate positioning, and the transfer speed can be increased to improve efficiency.

Further, since the piston block prevents the movement of the piston by utilizing the shape of the piston block and holds it in the protruding state,
In the extended state, the stopper is not only reliably held in the extended state by the piston block, but also in the event of a power outage, etc., the piston block is retained by the elastic means that urges the piston block in a direction that intersects with the direction of movement of the piston. Moreover, as already mentioned, since the piston is prevented from moving by utilizing the shape of the piston block, if the piston and the stopper are moved in and out, Even if a force is applied to the stopper, the force does not act on the elastic means, and the stopper is reliably maintained in its protruding state.

Furthermore, since the block drive means and the pressure oil supply means are provided on the pallet stand, the pallet can be held and released by the stopper independently on the pallet stand side without any action on the processing machine side. This makes it possible to provide a pallet clock device that is highly expandable, such as conveying pallets using a pallet stand.

In addition, since a pressure oil supply means is provided which can simultaneously supply pressure oil to the block drive means and the hydraulic supply path on the side where the piston of the hydraulic cylinder retreats, it is possible to release the holding by the pallet stopper and to release the stopper in the event of a power outage. At the same time, the disengagement operation of the piston block that is held in the protruding state can be easily performed with one touch by simply switching the pressure oil in the direction that releases the normal holding operation of the stopper against the pallet. It is possible to prevent accidental falling off during a power outage, etc., while maintaining the same ease of operation as when such a safety device is not installed.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the pallet locking device, which is the main part of the present invention, seen from the back of the pallet stand, Fig. 2 is a perspective view of a pallet changer to which the present invention is applied, and Fig. 3 is the main part of the pallet lock device according to the present invention. FIG. 4 is a side view showing the pallet, and FIG. 4 is a bottom view thereof. 1... Pallet changer, 2... Pallet stand, 5... Processing machine, 6... Table, 7...
Palette, 9... recessed part, 9a... linear part, 9b...
...Curved portion, 14...Clamp portion, 15...T-shaped groove, 16...Pallet lock device, 17...Reciprocating drive device (hydraulic cylinder device), 19...Safety protection device, 21...Piston, 22... Stopper (roller follower), 27... Piston, 30...
spring.

Claims (1)

[Scope of Claims] 1. In a pallet changer that transfers pallets between a processing machine side table and a pallet stand, the outer contour of the pallet clamping part is configured in a circular shape, and the pallet stand is used to hold the pallets. The recessed portion is formed into a U-shape consisting of a curved portion and a straight portion so that the outer shell of the clamp portion can be freely inserted and engaged, and a hydraulic cylinder device is provided on the pallet stand so that the piston can be freely driven to protrude. A stopper is provided on the piston so as to be able to protrude from the linear portion into the recessed portion when the piston is driven to protrude, and a piston block is attached to the hydraulic cylinder device so that the piston is moved from a direction intersecting the moving direction of the piston by an elastic means. The stopper is provided so as to be able to be held in a protruding state by engaging with the shape of the piston block to prevent movement of the piston; A block drive means is provided which is driven so as to be released from the engagement state with the piston against the pressure, and pressure oil is simultaneously supplied to the block drive means and the hydraulic pressure supply path of the hydraulic cylinder on the side from which the piston retreats. A pallet locking device for a pallet changer, which is configured with a pressurized oil supply means.