JPH0131419Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a discriminating device for discriminating workpieces sent through an assembly line, for example, based on their size. The present invention relates to a device that determines the size of a workpiece based on the amount of retraction of the workpiece upon contact with the workpiece.

[Prior art]

For example, there is a need for a device that can automatically distinguish between various similar workpieces (processed products) that are sent to an automobile assembly line. As a conventional discrimination device, there is one in which a piston protrudes from a forward cylinder that advances toward a workpiece, contacts the workpiece, and retreats, and the size of the workpiece is discriminated based on the amount of retreat and the like.

An example of such a conventional technique will be explained with reference to FIG. A fixed cylinder 2 is provided in a fixed housing 1 of the discrimination device. The piston 3 of the fixed cylinder 2 moves the moving housing 4. The moving housing 4 is provided with a forward cylinder 5, from which a piston 6 projects toward the workpiece. Due to the action of the fixed cylinder 2, the forward cylinder 5 moves forward together with the movable housing 4 toward the workpiece 7. When the piston 6 of the forward cylinder 5 comes into contact with the workpiece 7, it retreats against the force of the coil spring 8 present in the forward cylinder 5. By electrically checking the amount of retreat and the amount of advancement of the forward cylinder 5, the size of the workpiece is determined. For this electrical check, proximity switches 9 and 10 are used, for example, as in this prior art example. The proximity switches 9 and 10 are connected to a dog 11 provided on the movable housing 4 or a piston 6 of the forward cylinder 5.
The approach of the dog 12 provided on the body is sensed as the approach of a metal body. Of course, this proximity switch can also be a limit switch whose contacts actually touch. In addition, Dotsugu 1
By increasing the number of proximity switches 2 and proximity switches 10, it is also possible to discriminate the sizes of three or more types of workpieces.

However, in the conventional discriminating device described above, the device is large as a whole and requires a large space for installing the device.

[Purpose of invention]

The purpose of the present invention is to downsize a workpiece discrimination device and reduce the installation space for the device.

[Means to achieve the purpose]

The small workpiece discrimination device of the present invention has a cylinder formed within the piston of a fixed cylinder to serve as a forward cylinder. This eliminates the need to separately provide a moving housing and a moving cylinder, making it possible to downsize the device and narrow the space for installing the device.

[Example of idea]

An embodiment of the present invention will be described with reference to FIGS. 1 and 2. Fixed cylinder 2 for fixed housing 1
are fixed with bolts 21. A piston 3 is present in the fixed cylinder 2, and pressure oil is injected from above and below by sandwiching a gasket 22 provided on the piston, and the piston 3 moves up and down, that is, advances and retreats. The piston 3 protrudes from above and below the fixed cylinder 2, and the upper end of the fixed cylinder 2 is sealed by a cap 24 via an O-ring 23 to maintain watertightness.

A cylinder is formed within the piston rod 3 of the fixed cylinder 2 and serves as a forward cylinder 5. A backward piston 6 is housed inside the forward cylinder 5, and a coil spring 8 in the forward cylinder 5 is housed inside the forward cylinder 5.
is urged in the forward direction by. The tip of this retraction piston 6 is the part that comes into contact with the workpiece 7. A dog 12 is provided at the rear end of the retraction piston 6, as in the prior art. Also, this dog 12
A proximity switch 10 sensitive to the approach of is fixed to the advance cylinder 5. A similar proximity switch 9 is also provided in the fixed housing 2 and is adapted to respond to the approach of a dog 11 provided at the rear end of the forward cylinder 5.

The operation of this embodiment will be explained below. When the workpiece 7 is sent through the assembly line and reaches a predetermined position, the fixed cylinder 2 of the discriminating device operates to advance the forwarding cylinder 5 integrally formed within the piston 3 toward the workpiece 7. A retreat piston 6 protrudes from the tip of the advance cylinder 5. The tip of the retraction piston 6 eventually comes into contact with the workpiece 7 and stops moving forward. Further, when the forward cylinder 5 moves forward, the backward piston 6 moves backward relative to the forward cylinder 5. This retraction is performed against the force of a coil spring 8 provided within the forward cylinder 5. Eventually, the forward cylinder 5 stops moving forward after moving forward by a certain amount. The amount of advancement of the forward cylinder 5 and the amount of retraction of the retraction piston 6 at this time are determined by the actions of the proximity switches 9, 10 and the dogs 11, 12. Then, the size of the workpiece 7 is determined based on the amount of retraction of the retraction piston rod 6. That is, when the rear proximity switch 10 is OFF and the front one is ON, it is determined that the workpiece is of low height. Also, if the rear proximity switch is turned on and the front one is turned off, it is determined that the workpiece is tall. Note that both the front and rear proximity switches are normally turned off. When these determinations are made, it is necessary to know how far the forward cylinder has moved forward, and this amount of forward movement is determined by another proximity switch 9 and dog 11.

According to this embodiment, the fixed cylinder 2, the forward cylinder 5, and the backward piston 6 are arranged concentrically, so that the device can be made smaller in the radial direction. Further, since the forward cylinder 5 is formed within the piston 3 of the fixed cylinder 2, it is possible to achieve miniaturization of the device in the length direction. Therefore, unlike the conventional example (FIG. 3), there is no need to provide the moving housing 4, and there is no need to provide the moving cylinder 5 separately. Since the device can be made smaller in the radial and longitudinal directions, it is possible to provide an overall compact discriminating device. Furthermore, in the above embodiment, most of the parts constituting the device, such as the fixed cylinder 2, the forward cylinder 3, and the retracting piston 6, can be machined using round parts. without the need for a square one. Manufacturing costs can also be reduced.

Note that the discrimination in the above embodiment is made based on the amount of advance of the forward cylinder 5 and the amount of retreat of the retracting piston 6 (piston protruding from the forward cylinder), but in other embodiments, the amount of retraction of the retracting piston 6 is used. It is also possible to discriminate only based on the amount of retreat.

[Effect of idea]

According to the workpiece size discriminating device of the present invention, since the advancing cylinder is formed within the piston of the fixed cylinder, it is possible to achieve miniaturization of the device not only in the radial direction but also in the length direction.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a small workpiece discrimination device according to an embodiment of the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a longitudinal sectional view of a conventional discrimination device. 1...Fixed housing, 2...Fixed cylinder,
3... Piston, 4... Moving housing, 5...
Forward cylinder, 6... piston, 7... workpiece,
8...Coil spring, 9,10...Proximity switch,
11, 12...Dotsugu, 21...Bolt, 22...
...Putskin, 23...O-ring, 24...Cap.

Claims (1)

[Claim for Utility Model Registration] A forward cylinder moves forward toward the workpiece by the piston of the fixed cylinder, and the piston protruding from the forward cylinder contacts the workpiece and retreats, and the size of the workpiece is determined by the amount of retreat. A small workpiece discriminating device, characterized in that a cylinder is formed within the piston of the fixed cylinder to serve as the forward cylinder.