JPH0541526B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a stopper device for a pallet conveyor that circulates a plurality of pallets in a free cycle and stops them at a predetermined work station.

Prior Art Recently, many pallet conveyors have been used for automatic assembly of various products, which circulate multiple pallets in a free cycle, stop them at a predetermined work station, and perform the predetermined work at that position. has been done. Among these, the most common method is to arrange an endless chain on a conveyor frame that forms the main transfer path, transmit the traction force of the endless chain to the pallet, and move the pallet along the conveyor frame. With this type of pallet conveyor,
A clutch mechanism with a complex structure is configured to turn on and off the traction force of the endless chain and transmit it to the pallet, but the cost of this device is high, and the frictional force between the endless chain and the pallet is A pallet conveyor has been developed in which the traction force of an endless chain is transmitted to the pallet, thereby eliminating the need for an expensive clutch mechanism.

As shown in FIGS. 6 to 8, the pallet conveyor 1 has an endless chain 3 that circulates in a fixed direction on a horizontally arranged conveyor frame 2.

A substantially rectangular plate-shaped attachment 6 is attached to the endless chain 3 and also serves as a connecting plate, and this attachment 6 is arranged so as not to come into contact with an adjacent one.

On the other hand, a plurality of pallets 10 are movably mounted on the conveyor frame 2, and four rollers 9 are rotatably fixed to the lower part of the pallets 10. At the forward end and the backward end of this pallet 10, points symmetrical with respect to the center of the pallet 10 are provided.
That is, cam followers 11 and 11a, which form protrusions, are arranged at opposite positions at a predetermined distance from the center. Moreover, on the side of the pallet 10 there are 2
Friction plates 7, 7a are arranged, and these friction plates 7, 7a are connected to the attachment 6.
Made of wear-resistant material with a high coefficient of friction. The friction plate 7a is fixed to the pallet 10, and the other friction plate 7 is attached to the pallet 10 via a spring 13 so as to be freely retractable.

A stopper device 12 is attached to the conveyor frame 2 of the pallet conveyor 1 in order to stop the pallets 10 at a predetermined position. This stopper device 12 has a rotatable rear stopper 17 as shown in FIG.
The pallet 10 is positioned on the moving path of the pallet 10 and comes into contact with the cam follower 11a, thereby stopping the pallet 10. The rear stopper 17 is also rotatably connected to a small rod 20a of a small cylinder 20 that reciprocates up and down, so that the rear stopper 17 can be rotated arbitrarily by the operation of the small cylinder 20. .

Problems to be Solved by the Invention In this type of stopper device 12, as shown in FIG.
After the pallet conveyor 1 is locked by the front stopper 21 and the rear stopper 17, respectively, the rear stopper 17 retreats and the cam follower 11a begins to move, the pallet conveyor 1 may come to an emergency stop. In this case, when the pallet conveyor 1 comes to an emergency stop, the small cylinder 10 operates to move the rear stopper 17 to the cam follower 1.
Pallet 1 is located on the moving path of 1a and is being moved.
0, the upper surface of the stopper 17 may come into contact with the lower surface of the cam follower 11a after returning to the upward position, and the pallet 10 may be lifted. Therefore, palette 10
The friction plates 7, 7a and the attachment 6, which are attached to the pallet 10, come apart, causing problems such as the pallet 10 stopping. Also. In view of the above drawbacks, the rear stopper 17 is replaced with the cam follower 11a.
When returning to the path of travel, use a spring (not shown).
A device has been devised in which the return force of the rear stopper 17 is reduced by utilizing the elastic force of the rear stopper 17.
Since the rod 20a of the small cylinder 20 that retracts the small cylinder 20 is directly connected to the rear stopper 17, the elastic force of the spring must be increased in consideration of the frictional force of the piston (not shown) in the small cylinder 20. . However, when the elastic force of the spring is increased, the frictional force of the piston varies greatly each time the piston moves, and when this frictional force becomes small, the return force of the rear stopper 17 becomes a large elastic force itself, and the above-mentioned problem still remains. It has become impossible to remove the defects.

Means for Solving the Problems The present invention aims to eliminate the above-mentioned drawbacks.
Pallets are movably arranged along the conveyor frame. A projection is arranged at the bottom of the pallet, and a guide block is arranged corresponding to the projection. A stopper is rotatably arranged along this guide block,
This stopper is connected to the upper end of the drive member which is normally held rotatably in an upright direction by a spring. On the other hand, a cylinder having a rod that moves forward against the elastic force of the spring is arranged at a position away from the other end of the drive member, and as the rod moves forward, the drive member tilts and the stopper is moved toward the protrusion. It is configured to retreat from the path of travel.

Function: In this stopper device, when a pallet passes, the protrusion of the pallet engages with the stopper, and the pallet is positioned. Thereafter, when the rod moves forward to move the drive member downward and retreat from the path of movement of the stopper protrusion, the pallet begins to move due to the traction force of the endless chain. When the protrusion of the pallet reaches above the stopper, the pallet conveyor makes an emergency stop and the rod moves back, causing the drive member to return upward. The stopper is urged upward by the drive member, so that the stopper rises and collides with the lower surface of the protrusion of the pallet.
However, since the driving member is only urged by the elastic force of the spring, the stopper does not return to the upward position any further. Therefore, the pallet is not pushed up by the stopper and stops at that position.
Even if the pallet conveyor is driven again, the pallets can be moved without any problem. Moreover, since the driving member is separated from the rod of the cylinder, the elastic force of the spring is not affected by the cylinder and is only small enough to rotate the driving member, preventing the stopper from colliding with the pallet. However, the pallet will not be damaged in any way.

Examples Examples are described above with reference to the drawings. 1 to 3, a stopper device 12 is attached to a conveyor frame (not shown) of a pallet conveyor (not shown). This stopper device 12 has a stopper plate 14, and this stopper plate 14 has a cam follower 1 at the forward end of the pallet 10.
A front guide block 15 and a rear guide block 16 are fixed to guide the cam follower 11a and the rearward end cam follower 11a, respectively. The front guide block 15 is connected to the cam follower 1 at the forward end of the pallet 10.
It is fixed corresponding to 1. The front guide block 15 has a guide surface for guiding the cam follower 11, and this guide surface is configured to form a reference surface for positioning the cam follower 11. The front guide block 15 also has a front stopper 2.
1 is arranged to push the cam follower 11 forward, and the front stopper 21 has a rotary lever 2 rotatably attached to the stopper plate 14.
2 are linked together. Further, a first rod 24a of a first cylinder 24 rotatably attached to the stopper plate 14 via a fitting 23a is fixed to the front stopper 21, and its operation causes the front stopper 21 to advance and rise. Cam follower 1
It is configured to reach the travel path of No. 1.

Further, the rear guide block 16 has a guide surface for guiding the cam follower 11a, and this guide surface serves as a reference surface for positioning the cam follower 11a. A rear stopper 17 is attached to the rear guide block 16 and is rotatable along the guide surface, and a shock absorber 19 is integrally fixed to the lower part of the rear stopper 17.
Further, the rear stopper 17 is provided with a long groove 17a extending in its length direction.
A sliding pin 18a fixed to a link 18 constituting a driving member is slidably inserted into a. The link 18 is fixed to a fixture 23b fixed to the lower surface of the stopper plate 14 so as to be rotatable about a pin 25. A spring 26 is fixed to one end of the link 18, so that the link 18 This spring 2
6, it is always biased to stand upright. The elastic force of the spring 26 may be small enough to rotate the link 18 having the rear stopper 17 at its upper end. Further, a small cylinder 20 is fixed to the fixture 23b such that its small rod 20a is located away from the link 18 and near the other end of the link 18, and the small rod 20a is attached to the spring 26. When it moves laterally against the elastic force and comes into contact with the link 18, the link 18 inclines and the rear stopper 17 separates from the path of movement of the cam follower 11a of the pallet 10.

Further, the front stopper 21 and the rear stopper 17 have slopes that are inclined with respect to the direction of movement of the cam followers 11 and 11a, and these slopes intersect with the front guide block 15 and the rear guide block 16 at an acute angle, and the cam followers 11 and 11a intersect at an acute angle. ,11
It is configured to move a to the reference plane side.

In the above pallet conveyor stopper device, an endless chain 3 is installed along the conveyor frame 2.
When the friction plates 7, 7a and the pallet 10 move in a circular manner, the friction plates 7, 7a and the pallet 10 move together.

When the pallet 10 moves to a predetermined working position, the cam follower 11a at the rearward end contacts the shock absorber 19 and the rear stopper 17 to stop, as shown in FIG. 4a. When the pallet 10 stops at the approximate position, the first cylinder 24 is actuated as shown in FIG. 4b, and the front stopper 2
1 to advance and rise. Therefore, the front stopper 21
comes into contact with the cam follower 11 at the forward end, bringing it into contact with the front guide block 15, and the rear stopper 17 ensures that the cam follower 11a at the rear end comes into contact with the rear guide block 16, so that the pallet 1
0 is positioned at that position.

When the predetermined work is completed at this position, the small cylinder 20 is activated. Therefore, the small rod 20a
moves forward and contacts the link 18, causing the link 18 to tilt. As the link 18 tilts, the sliding pin 18a slides along the long groove 17a of the rear stopper 17, and the rear stopper 17 rotates to move the cam follower 1.
It separates from 1a and pallet 10 begins to move.

If the pallet conveyor 1 comes to an emergency stop when the cam follower 11a reaches directly above the rear stopper 17, the small cylinder 20 moves back and the link 18 returns to the upright direction by the spring 26. Therefore, as shown in FIG. 4c, the rear stopper 17 returns to the upward position and collides with the lower surface of the cuff follower 11a, but since the link 18 is only pushing up the rear stopper 17 by the spring 26, the pallet 10 is pushed up. Without a doubt, the rear stopper 17
will stop at that position. Further, at this time, the elastic force of the spring 26 is small enough to rotate the link 18 to which the rear stopper 17 is locked at the upper end, and the elastic force of the spring 26 acting on the link 18 is also influenced by the small cylinder 20. Since it is constant without being affected, there is no sudden large elastic force acting on it.
There is no possibility of pushing up the rear stopper 17 or damaging the rear stopper 17. When the pallet conveyor 1 is driven again in this state, the pallet 10 can be smoothly moved by receiving the traction force of the endless chain 3.

EFFECTS OF THE INVENTION As explained above, the present invention uses a spring to urge a driving member, one end of which is locked to a stopper located on the path of movement of the protrusion of a pallet, to stand upright, and the other end of the driving member Since a reciprocating drive source having a rod that moves forward against the spring is placed at a position away from and close to the spring, the elastic force of the spring always changes regardless of the operation of the reciprocating drive source. Rather, the spring may have a small elastic force sufficient to rotate the driving member,
Moreover, even if the pallet comes to an emergency stop and the stopper collides with the protruding part of the pallet when the stopper returns to the upward position, the pallet not only does not want to be pushed up by the stopper, but also the stopper may be damaged. This has the advantage that there is no such problem. In addition, in the example, as shown in FIG.
Link 1 rotatably arranged around pin 25
8, the rear stopper 17 is raised and returned using two first levers 27 and second levers 28, and the first lever 27 and second lever 28 are bent by the small rod 20a of the small cylinder 10. The same effect will be achieved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main part of the present invention, Fig. 2 is an enlarged front view of the main part of the invention, Fig. 3 is a plan view of Fig. 2, Fig. 4 is an explanatory diagram of the operation of the invention, and Fig. 5 6 is a cross-sectional view of a main part of a pallet conveyor according to the present invention, and FIG. 7 is a cross-sectional view of a main part taken along line B-B in FIG. 6. 8 is a partial view of the endless chain according to the present invention, FIG. 9 is a front view of the main part of the conventional example, and FIG. 10 is an explanatory diagram of the operation of the conventional example. 1... Pallet conveyor, 2... Conveyor frame, 3... Endless chain, 6... Attachment, 7, 7a... Friction plate, 9... Roller,
10... Pallet, 11, 11a... Cam follower, 12... Stopper device, 13... Spring, 14
...Stopper plate, 15...Front guide block, 1
6... Rear guide block, 17... Rear stopper,
17a...long groove, 18...link, 18a...sliding pin, 19...shock absorber, 20...
Small cylinder, 20a...Small rod, 21...Front stopper, 22...Rotating lever, 23a, 23b...
...Fixing tool, 24...First cylinder, 24a...First rod, 25...Pin, 26...Spring, 27...
...first lever, 28...second lever.

Claims (1)

[Claims] 1. In a pallet conveyor configured to move pallets in a predetermined direction along the conveyor frame, a protrusion is disposed at the bottom of the pallet, and a guide block is disposed corresponding to the protrusion. At the same time,
A stopper is rotatably disposed along this guide block, and this stopper is connected to the upper end of a drive member which is always rotatably held in an upright direction by a spring, while the stopper is connected to the upper end of a drive member that is rotatably held in an upright direction by a spring, and is separated from the other end of the drive member. A stopper device for a pallet conveyor, characterized in that a reciprocating drive source having a rod that moves forward against the elastic force of a spring is arranged at a position.