JPS5913047B2 - automatic positioning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic positioning device that uses a hydraulic or pneumatic cylinder to control the position of, for example, a table of a machine tool.

Conventionally, when positioning is controlled using hydraulic or pneumatic cylinders, such as 3-position control of a machine tool table,
A positioning method is adopted in which a detector such as a limit switch or potentiometer is used to detect the position of the cylinder, the output signal of the detector is used as a feed pack signal, and the cylinder is controlled by comparing this feedback signal with the target position. 0 was there.

However, with this positioning method, the number of devices used increases and the circuit becomes complicated because it is necessary to feed back signals from the detector. The present invention has been made with attention to the above-mentioned points, and includes a hydraulic or pneumatic cylinder that is rotatably supported and one
5. Connected to the load side via a link that always has a return force to a predetermined position by a return spring, and the cylinder is driven by a solenoid valve whose switching is controlled by a pulse signal having a predetermined pulse width depending on the switching position of the switch. The present invention provides an automatic positioning device that positions the load side by controlling the stroke position to a predetermined stroke position.

An embodiment of the present invention will be described below based on the accompanying drawings.

In the figure, pulse generators 2a, 2b and 52c changeover switch 1 switch to respective contacts 1a, lb, and Ic to generate pulse signals pa-p with fixed time widths ta, tb, and tC.
Output c.

2a, 2b 3 position solenoid valve 3 is solenoid 3Sa, 3Sb
When energized, they are switched to positions 3A and 3B, respectively.

2 position 30 solenoid valve 4 is switched to position 4A when solenoid 45 is energized.

These solenoid valves 3, 4 are switched to positions 3C, 4B when no signal is applied. hydraulic cylinder 5
is connected to the 3-position solenoid valve 3 and the 2-position solenoid valve 4, and is operated by switching each solenoid valve 3, 354, and its stroke is forward, return, or free movement for a time depending on the pulse signal width, and the solenoid valve After returning, the operating position is maintained at positions 3C and 4B. The link 6 is rotatably supported at approximately the center thereof, and one end 6a has a piston rod 9 of a hydraulic cylinder 5, and the other end 6b has a predetermined load, such as the rod of a cylinder for driving a table of a machine tool. 10
is rotatably connected to.

Further, the link 6 is given a tension of 7J1 by return springs 7 and 8 so that it always returns to the neutral position (the position shown in the figure). The link 6 is connected to each contact point 1 of the switch 1.
Depending on the switching positions of a, 1b, and 1c, positions A, B, and C, respectively.
controlled by. Here, the switching operation of the switch 1 may be performed manually or may be performed automatically by an input signal from another device.

In the automatic positioning device configured in this way, if the switch 1 is now switched to the contact 1a, the pulse generator 2a
outputs a pulse signal Pa with a pulse width Ta, and switches the 3-position solenoid valve 3 to position 3A.

Therefore, the rod 9 of the hydraulic cylinder 5 is extended and the link 6
Rotate to position A. The stroke of the cylinder 5 and the rotation angle of the link 6 are determined by the pulse width T of the pulse signal Pa.
It corresponds to AVC. After time Ta has passed, the solenoid valve 3 returns to the neutral position 3C, the hydraulic cylinder 5 is stopped and held at the operating position, and the link 6 is moved by the spring 7,
8 and is locked and held at the position A. Next, when switch 1 is switched to contact 1b, pulse signal Pb with pulse width Tb is output from pulse generator 2b, and solenoid valve 3 is moved to position 3B.
Switch to

Therefore, the rod 9 of the hydraulic cylinder 5 shortens its stroke by a stroke corresponding to the pulse width Tb, and the link 6 is rotated to the B position. Then, similarly to the above, the electromagnetic apex 3 is at the neutral position 3.
Even after returning to C, the link 6 is retained and held at the operating position.
Further, when the switch 1 is switched to the contact 1c, the pulse generator 2c outputs a pulse signal Pc with a pulse width Tc, and the 2-position solenoid valve 4 is switched to the open center position 4a.

As a result, the hydraulic cylinder 5 becomes free to move, and the link 6
is returned to the neutral position C by the tensile forces of the springs 7 and 8 from the left and right sides, and even after the solenoid valve 4 returns to the closed center position 4B, it is retained in that position. In this manner, the link 6 is rotated and held at positions A, B, and C in response to the switching operation of the switch 1 to the contacts 1a to 1c, thereby controlling the positioning of a predetermined load via the rod 10.

Here, the time widths Ta and Tb of the pulses are usually set to be a time sufficient to travel from the stroke start end to the end end of the cylinder, or from the end end to the start end. Note that the hydraulic cylinder 5 and the link 6 are connected in such a way that the cylinder 5 is fixed and one of the links 6 is connected.
The piston rod of the cylinder was connected to the end, but on the contrary, the piston rod 9 was fixed and one of the links 6
The head side of the cylinder may be connected to the end.

Furthermore, the cylinders used may be not only hydraulic cylinders but also pneumatic cylinders. As explained above, according to the present invention, a limit switch that detects the cylinder position;
Since no detector such as a potentiometer is used, the structure is simplified and the device can be made inexpensive.

Further, there are advantages such as the ability to obtain an automatic positioning device that does not require any feedback signals.

[Brief explanation of the drawing]

The figure is a block diagram showing one embodiment of an automatic positioning device according to the present invention. 1...Switch switch, 2a-2c...
Pulse generator, 3...3 position solenoid valve, 4...
...2 position solenoid valve, 5... cylinder, 6...
...Link, 7, 8...Spring, 9...
··rod.

Claims (1)

[Claims] 1. A cylinder that is rotatably supported and connected to the load side via a link that always has a return force to the neutral position due to a spring force, and that controls the position of the load side by driving the link according to the stroke position; a spring center type three-position solenoid valve having first and second solenoids and having a neutral position for stopping the flow of working fluid from the cylinder; and a third solenoid and having a neutral position for stopping the flow of working fluid from the cylinder; a two-position solenoid valve of the spring offset type having an offset position for stopping fluid flow and an operating position for freeing the flow of working fluid from said cylinder; When the switch is operated, a pulse signal having a pulse width longer than the longest of the time required for the cylinder rod to reach the stroke end and the time required for the link to return to the neutral position after the third solenoid is energized is activated. a pulse generator that outputs an output to one of the first, second, and third solenoids in response to the pulse generator.