JPH0475844A - Pallet exchanging device - Google Patents

Abstract

PURPOSE:To use a small cam for a cam mechanism for driving an exchange arm by performing lift operation during exchange of a pallet by means of the clamping device of a table. CONSTITUTION:In exchange of a pallet, a pallet P1 on a table 1 is lifted by height (a) by means of a clamping member 15 through unclamping operation of a clamping device 16, and a positioning pin 20 is pulled off from a positioning recessed part 19 in the under surface of the pallet P1. In linkage with the lifting, a unit exchange arm 9a is raised through an exchange arm lifting cylinder 32 by means of a cam mechanism 26. The unit exchange arm 9a continues rise of it by height (b) even after lifting of the pallet P1 by means of the clamping device 16 completed, and the pallet P1 is slightly levitated from the table 1. A pallet Ps on the preparation side is raised by height (b) by the cam mechanism 26 after lifting of the pallet P1 on the machining side by means of the clamping device 16 is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pallet changing device applied to machining centers and the like.

[Conventional technology]

Conventionally, as a pallet exchange device, as shown in FIG. It has been proposed that the device be replaced by gripping it and rotating the replacement arm 83.

The exchange arm 83 is attached to a rotating shaft 86 supported by a support member 85 so as to be rotatable and movable, and after rising and lifting the pallets Pal and Pa2, it turns.

By this lifting, the positioning bin 87 of the rotary table 81 is pulled out from the positioning hole on the lower surface. Exchange arm 83
The rotation and elevation drive of is performed by one motor (not shown) via a cam mechanism 88. Elevation drive by the cam mechanism 88 is performed by a cam plate 89 and a rotating lever 9o.

[Problem to be solved by the invention]

However, according to the configuration shown in FIG. 6, the load of the cam plate 89 is applied over the entire range of the lifting and lowering stroke of the exchange arm 83, so that the cam curve of the cam plate 89 cannot be made steep. This is not possible, and the cam plate 89 has a large diameter.

Therefore, there is a problem that the pallet exchanging device becomes larger.

An object of the present invention is to provide a pallet exchange device with a simple structure in which a small-diameter cam can be used in the cam mechanism for driving the exchange arm up and down, and the overall size can be reduced.

[Means to solve the problem]

In the pallet exchange device of the present invention, the clamp device provided on the table is configured to be able to lift the pallet by unclamping operation, and after lifting, the exchange arm is raised to lift the pallet from the clamp device, and the pallet can be exchanged. It is equipped with a cam mechanism that rotates the arm.

The exchange arm is provided between the table and the pallet/soto pedestal so that it can move up and down and rotate horizontally, and has a pallet gripping mechanism at its tip. The table is provided with a protruding positioning pin that engages with a recess on the lower surface of the pallet. The clamping device clamps the pallet by a downward movement.

[For production]

The pallet on the table is clamped by a clamping device with the recessed portion of the lower surface fitted into the positioning pin of the table.

When replacing the pallet, by unclamping the clamping device, the pallet/soto is lifted by the clamping device, and the positioning pins are removed from the recesses on the lower surface of the pallet/soto. Thereafter, the pallet is further lifted by raising the exchange arm by the cam mechanism, and in this state, the exchange arm rotates to exchange the pallet position.

〔Example〕

An embodiment of the present invention will be described based on FIGS. 1 to 5.

As shown in FIG. 3, a rotating table l carrying a pallet P1 on the processing side is installed at a fixed position on the head 2, and is slid via a spindle stand 4 on which a spindle 3 is movable up and down, or via a rail 5. It is mounted on pedestal 6. The slide stand 6 is installed on rails 7 on the bed 2, and the spindle stand 4 is driven in the lateral direction (X-axis direction) and the front-rear direction (X-axis direction) along these rails 5.7.

A pallet pedestal 8 on which a pallet P2 on the setup side is placed is arranged in line in front of the table 1, and an exchange arm 9 of a pallet exchange device 10 is installed between the table 1 and the pallet pedestal 8. The replacement arm 9 is the cam box 1
180 around the center of rotation 0 by the cam mechanism described later in 1.
It rotates at 100 degrees and moves up and down.

The pallets PI and P2 are attached to the fixtures 12 as shown in FIG.
A workpiece W is mounted through the clamp groove, and a dovetail-shaped clamp groove 13 is provided on the lower surface.

The clamp groove 13 is formed in an arc shape with the rotation center 0 of the exchange arm 9 as the center of the arc (FIG. 3).

In FIG. 1, the table l is installed on the indexing device 14 and performs index rotation every 90',
Clamp device 1 having a clamp member 15 having a T-shaped cross section
6 is built into the center. The clamping device 16 consists of a hydraulic cylinder.

The clamp member 15 is fitted into the clamp groove 13 of the pallet PI and clamped by a downward movement, and has an arcuate planar shape that matches the clamp groove 13 (FIG. 3). A central positioning pin 18 is protruded from the upper surface of the clamp member 15, and is fitted into the central positioning hole 17 on the lower surface of the pallet P1 in an unclamped state. Palette P
Positioning recesses 19 are provided at two diagonal corners of l.
- A positioning pin 20 protruding from the upper surface of the table 1 is fitted. Both pallets PI and P2 have the same configuration.

The pallet pedestal 8 is horizontally rotatably installed on the cam box 11 with a bearing 21, and has a center positioning pin 22 projecting from the upper surface that fits into the center positioning hole 17 of the pallet P2.

The exchange arm 9 includes two unit exchange arms 9a.

9b, and each unit exchange arm 9a, 9b is provided with a pallet gripping mechanism 27. Pallet gripping mechanism 27
has an arcuate protrusion 28 which is an engaging portion and a retaining piece 29, and the arcuate protrusion 28 is attached to the pallet P1. It engages with the arcuate groove 31 of the engaged portion 30 protruding from P2. The arc center of the arc protrusion 28 and the arc groove 31 is the rotation center R of the table 1 (
(Fig. 3).

Each unit exchange arm 9a, 9b is attached to a connecting member 24 at the upper end of a rotating shaft 23 through a dovetail-shaped guide portion 25 so as to be able to move up and down independently, and as shown in FIG. 2
The upper end of the exchange arm lifting cylinder 32, which is fitted onto the outside of the exchange arm 3, is placed on a member 33 and driven up and down. The rotating shaft 23 is rotatably supported by a bearing 39 at the lower end. The unit exchange arm 9b on the pallet holder 8 side is connected to the cam box 11.
It is supported at an intermediate height by a support rod 34 erected.

The retaining pieces 29 are plate-shaped pieces arranged on both sides of each unit exchange arm 9a, 9b, and are attached to the connecting member 24 on the rotating shaft 23.
and the unit exchange arm 9a is fixed together with the upper end plate 40.
, 9b, the engaged portion 3 of the pallet P], P2
It is placed at a height that engages and disengages from zero. The upper end plate 40 serves to prevent the unit exchange arm 9a9b from coming off upward.

The exchange arm lifting tube 32 is rotatably and vertically supported by the support member 35 of the cam hook 11 via a sleeve 36, and is rotationally transmitted from a gear 4I fixed to the lower end and engaged with the lever fitting groove 42. It is driven up and down by a rotating lever 38 shown in FIG. The gear 41 is connected to the intermediate shaft 44
It meshes with a drive gear 45 provided on the holder so as to be vertically movable. The intermediate shaft 44 is rotatably supported by upper and lower bearings 46 and rotationally driven by the cam mechanism 26 .

The cam mechanism 26 transmits the rotation of the horizontal shaft 48 to both the intermediate shaft 44 and the rotating lever 38 at a predetermined timing.
Rotation is transmitted from 7. The rotating lever 38 is supported by a support shaft 49 so as to be movable up and down, has a roller 43 that engages with the lever fitting groove 42, a cam follower 50 for pushing up, and has a branching lever portion 38a. A cam follower 51 for pulling down is provided.

As shown in FIG. 5, the two rotating levers 38
A cam follower 50 (FIG. 1) for pushing up is provided on both sides of the horizontal shaft 48 and rolls into contact with two main cam plates 52 of the horizontal shaft 48. The cam follower 51 for pulling down is provided to ensure reliable operation, and is provided only on one of the rotating levers 38 and rolls into contact with the auxiliary cam plate 53 of the horizontal shaft 48. Horizontal axis 4
A grooved cam 54 is provided at the center of the intermediate shaft 44, and a plurality of cam followers 55 for vertical transmission are provided radially around the intermediate shaft 44.
However, a large number of cam grooves 54 formed on the circumferential surface of the grooved cam 54
Each meshes with a.

The operation of the above configuration will be explained. As shown in FIG. 1, during machining, the pallet P1 on the machining side is placed on the table with the positioning recess 19 on the lower surface fitted with the positioning pin 20.
When the clamp device 16 is driven downward, the clamp member 15 is pressed against the upper surface of the table 1 and clamped.

The pallet P2 on the setup side has the center positioning hole 17 on the bottom surface.
is placed on the pallet holder 8 while being fitted into the center positioning pin 22 of the pallet holder 8.

The exchange arms 9 stand by at an angle such that each unit exchange arm 9a, 9b faces the table l and the pallet holder 8, respectively. The replacement arm lifter 32 is lowered and the table 1
The side unit exchange arm 9a is at the lower end. The unit exchange arm 9b on the pallet pedestal 8 side is mounted on a support rod 34 and supported at an intermediate height.

At this time, the arcuate protrusion 28 of each unit exchange arm 9a, 9b
, the arcuate grooves 31 of both pallets PI and P2 remain engaged, but since these arcuate protrusions 28 and arcuate grooves 31 are located at the arc center or the rotation center R of the table 1 (Fig. 3), the pallet P.L.

There is no interference due to the rotation of P2. Therefore, indexing rotation of the rotary table 1 and rotation of the pallet holder 8 can be freely performed while remaining in the engaged state. Depending on the rotation angle, the arcuate groove 31 is disengaged from the arcuate protrusion 28 or engaged with it again.

The rotary table 1 is installed at a fixed position, but since the spindle 3 moves back and forth (Z-axis direction) and left and right (X-axis direction), any part of the workpiece W on the pallet P1 can be processed. The pallet P2 on the setup side is freely rotated by hand by the operator together with the pallet holder 8 so that the work W can be easily attached and detached.

When processing is completed, each pallet P1. P2 returns the rotation angle at which the engaged portion 30 is located on the side of the unit exchange arms 9a, 9b.

When replacing pallets, pallet P in table 1 is
By the unclamping operation of the clamp device 16, the clamp member 15 is lifted by a height a (FIG. 1), and the positioning bin 20 is pulled out from the positioning recess 19 on the lower surface of the pallet P1. In synchronization with this lifting, the unit exchange arm 9a is raised by the cam mechanism 26 via the exchange arm lifting cylinder 32.

The unit exchange arm 9a continues to rise by the height b even after the lifting of the pallet P1 by the clamp device 16 is completed, and lifts the pallet Pi slightly above the table.

The height of the setup-side pallet P2 placed on the pallet pedestal 8 is the same as the height of the processing-side pallet P1 when lifted by the clamp device 16, and the unit exchange arm 9b
is also supported by a support rod 34 at a corresponding height. Therefore, the processing side pallet by the clamp device 16
After the lifting of the point P1 is completed, it is raised by the cam mechanism 26 by a height b.

In this way, the positioning bin 2 is
In order to lift the pallet P until it comes off from 0, the loads of the pallets Pi and P2 act on the cam mechanism 26 as follows.
This occurs only between the lifting height b. Therefore, in the main cam plate 52 for pushing up the cam mechanism 26, the section of the extraction height a can be formed to have a steep slope, and the main cam plate 52 can be formed to have a small diameter. Therefore, the cam mechanism 26
is miniaturized, and the entire pallet exchanging device 10 can be miniaturized. The floating height b is determined by the height b of the pallet P1 when the exchange arm 9 rotates. The height may be such that the lower surfaces of P2 do not rub against each other, and is set to about 5B, for example. The extraction height a is
For example, it is set to 25+o+.

In addition, in the section of height a, since no load acts on the main cam plate 52, the cam 7 lower 5 is applied to the main cam plate 52.
The exchange arm 9 may be left movable up and down without providing a cam curve that touches 0.

Both pallets PI and P2 are replaced by the unit exchange arm 9a.

When the pallet P1. The engaged portion 30 of P2 is sandwiched between the retaining pieces 29 from both sides. Note that after unclamping, until the pallet is held in place by the retaining pieces 29, the center positioning pin 18 of the clamp member 15 fits into the center positioning hole 17, thereby preventing the pallet P1 from shifting.

In this state that the exchange arm 9 is stopped by the stopper piece 29, the exchange arm 9 rotates 180 degrees together with the rotation shaft 23 by the drive of the cam mechanism 26, and the pallets PI on the processing side and the setup side,
Swap the position of P2.

After replacement, the cam mechanism 26 lowers the replacement arm 9, and the clamp device 16 performs clamping, completing the pallet replacement.

In the above embodiment, the exchange arm 9 is divided into a pair of unit exchange arms 9a, 9b, but both unit exchange arms 9a,
9b may be formed integrally, or it may be formed of only one unit exchange arm 9a, 9b.

The support rod 34 on the setup side does not necessarily need to be provided. Further, the clamp device 16 may use a drive source different from the cylinder device.

Lifting height a of pallet P1 by clamp device 16
may be a height at which the removal of the positioning pin 20 is not completed.

〔Effect of the invention〕

In the pallet exchange device of the present invention, the lifting operation during pallet exchange is performed by the clamp device on the table, so that the pallet needs only to be lifted by a small height by the exchange arm. Therefore, a small-diameter cam can be used for the cam mechanism that drives the exchange arm, and the cam mechanism can be downsized, making it possible to downsize the entire pallet exchange device. Further, since the clamp device is also used to lift the pallet, there is no need for a dedicated lifting means, and the structure is simple.

[Brief explanation of the drawing]

FIG. 1 is a cutaway front view of one embodiment of the present invention, FIG. 2 is a schematic plan view thereof, FIG. 3 is a plan view of the exchange arm, and FIG. 4 is a partially enlarged view of FIG. 1. FIG. 5 is an enlarged cutaway front view of the cam mechanism;
FIG. 6 is a fracture pressure surface diagram of a conventional example. DESCRIPTION OF SYMBOLS 1...Table, 3...Spindle, 8...Pallet pedestal, 9...Exchange arm, 9a, 9b...Unit exchange arm, 10...Pallet exchange device, 11...Cam box , I3... Clamp groove, 15... Clamp member, 16... Clamp device, I9... Positioning recess, 20... Positioning bin, 23... Rotating shaft, 2
4... Connecting member, 38... Rotating lever, 41...
Gear, 42... Lever fitting groove, 44... Intermediate shaft, 4
5...-driving gear, 48...horizontal axis, 50.51...
Cam follower, 52... Main cam plate, 53...
Auxiliary cam plate, 54...Groove cam, 55-Cam follower, a, b...Height, PI, P2...Pallet Patent applicant Murata Machinery Co., Ltd.

Claims (1)

[Claims] An exchange arm is provided between the table at the processing position on which the pallet is placed and the pallet holder so as to be able to move up and down and rotate horizontally, and has a pallet gripping mechanism at the tip, and an exchange arm that protrudes from the table and engages with a recess on the underside of the pallet. a locating pin provided on the table for clamping the pallet by a downward movement and lifting the pallet by a rising movement; and a cam mechanism for rotating and lifting the exchange arm and lifting the pallet from the clamping apparatus. A pallet changing device equipped with