JPS59132519A - Slow action type nonlap contact switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Object of the Invention) The slow-action menlap contact switch of the present invention is used, for example, in the field of switches that issue command signals for controlling the operation of press machines.

The switch of the present invention has an a contact and a b contact. When the switch is inactive, the a contact is off and the b contact is on. When the switch is activated, both the a and b contacts are off. This relates to a structure in which the a contact is turned on and the b# point is turned off.

(Prior Art) Conventionally, this type of switch has a structure shown in FIG. 9.

That is, the A contact 3 and the B contact 4 are placed opposite each other at an appropriate distance within the fixed frame 1, and the A contact 3 can be freely connected to and separated from the fixed A contact 3X fixed to the fixed frame 1 and the fixed A contact 3X. It consists of a movable A contact 3y facing each other, a B contact 1 is a fixed contact 4x fixed to the fixed frame 1, and a movable contact 4y facing the fixed contact 4X so as to be able to come into contact with and separate from it. A contact 3y
and the movable contact 4y, the fixed a contact 3X and the fixed contact 4\
Excess movement absorbing springs are placed back-to-back with an appropriate interval H1i between them, and press the movable A contact 3y toward the fixed A contact 3X side, and also press the movable contact 1y toward the fixed contact 4X side. 2 B is mounted across the movable contact 3y and the movable contact 4y, and the movable contact 4y is fixed from the contact 4X to a.
The movable a contact 3y is pushed away to the contact 3 side and the movable a contact 3y is fixed via the movable contact 4y and the excessive movement absorption spring 28.
An operating tool 8 to be brought into contact with the fixed frame 1 is supported so as to be able to slide forward and backward in the direction of separation between the a contact 3 and the b contact 4, and the outer end of the operating tool 8 is attached to the end wall of the fixed frame 1 on the b contact side. Protrude outward and move a
A return spring 6 that pushes the contact 3y away from the fixed A contact 3X toward the B contact 4 and brings the movable contact 4y into contact with the fixed contact 4x is mounted between the operating tool 8 and the fixed frame 1, and the A mounting hole 31 is formed in the tool 8, and the movable a contact 3y, movable contact 51y, and excessive movement absorbing spring 28 are inserted into the mounting hole 31, and the movable a contact 3y is received at the right end wall 30 of the mounting hole 31. At the same time, the movable contact X1. By receiving y, the distance between the movable A contact 3y and the movable contact 4y is always constrained to a smaller dimension than the distance between the fixed A contact 3X and the fixed contact [X]. ing.

When a switch with this structure is installed and used in a machine such as a press machine, it functions as follows.

That is, in the non-operating state where the mechanical force F for control commands such as a cam for detecting the timing of the machine does not act, the operating tool 8 is pushed to the left in the figure by the return spring 6, and the movable point a# 3v becomes the fixed a contact. 3X is pushed away to the left, the a contact is turned off, and the movable contact 4y is brought into contact with the fixed contact 4X, so that only the b contact 4 is turned on.

In the switch operating state where the control command mechanical force F acts,
After the operating tool 8 is pushed to the right and the movable contact 4y is pushed away from the fixed contact 4X to the right and the B contact is turned off, the movable A contact 3y is brought into contact with the fixed A contact 3X. As a result, only the a contact 3 is turned on.

However, this structure of the switch has the following drawbacks.

(a) An accident may occur in which the movable A contact 3y is welded to the fixed A contact 3X due to electrical discharge. In this case, fixed a contact 3
The movable contact 3y welded to X fixes the operating tool 8 in the operating position pushed to the right, and the switch is blocked in the operating state in which the a contact 3 is turned on and the b contact 4 is turned off.

Therefore, even though the switch should return to the non-operating state after the mechanical force F for control command is released, the switch remains in the activated state and issues a wrong signal, causing the machine to be erroneously controlled and run out of control. I'll let you.

In order to overcome this drawback, the two switch signals can be extracted and compared to detect a welding accident of the a contact and stop the machine.

Conventionally, in order to do this, two switches having the above structure were used, and when the signals output from both switches contradicted each other, it was determined that a welding accident had occurred in one of the switches. However, this has the following drawbacks.

(b) The number of switches must be doubled, which is expensive, and the detection means becomes complicated.

(c) When an error occurs in the timing of both switches and the same earth floor, it is mistakenly judged as if a welding accident has occurred even though no welding accident has occurred, and (the siege is stopped unnecessarily).

(d) When both switches cause a welding accident at the same time, it is incorrectly determined that no welding accident has occurred, making it impossible to prevent the machine from running out of control.

(Technical Problem of the Present Invention) A technical problem of the present invention is to enable, when a welding accident occurs at one contact, to turn on the other contact while keeping one contact welded. .

In this way, both contacts are in an abnormality detection state in which they are turned on, and it is possible to accurately detect the occurrence of a contact welding accident.

(Contents of the present invention) The purpose of the present invention is to eliminate the above-mentioned conventional drawbacks (a), (b), (c), and (d), and to eliminate the occurrence of a welding accident of the a contact with only one switch. The purpose is to enable accurate detection.

In the present invention to achieve the second object, the structure of the part supporting the movable a contact 3y in the structure of the conventional product shown in FIG. 9 mentioned above is changed, for example, as shown in FIG. 1 or FIG. It is characterized by improvements.

That is, the movable a contact point 3y is sandwiched between two opposing springs so that it is not restrained by the operating tool 8.

Its action is as follows.

That is, even if an accident occurs in which the movable A contact 3y is welded to the fixed A contact 3X, the movable A contact 3y welded to the fixed A contact 3X will compress the spring placed opposite the spring for simultaneously closing both contacts. It only restricts the operating tool 8 and the movable contact 4y.

Therefore, when the control command mechanical force F is released from the operating tool 8, the movable contact 4y is freely pushed and fixed by the spring 5 for simultaneously closing both contacts, and comes into contact with the contact 4x. Due to this, the a contact 3 and the b contact 4 are brought into an abnormality detection state in which they are both turned on at the same time, and the occurrence of a welding accident of the a contact 3 is accurately detected.

The present invention operates as described above and has the following effects.

(b) If the A contact 3 causes a welding accident, the B contact 4
is turned on without being restrained by the welding accident at contact 3, and enters an abnormality detection state in which both the a and b contacts are turned on at the same time, so it is possible to accurately determine that the a contact 3 has caused a welding accident. can be detected.

As a result, if the switch of the present invention is used, when a welding accident of the a contact 3 occurs, the machine will be stopped based on the accurate detection of the occurrence of the accident, thereby eliminating the occurrence of runaway accidents due to incorrect control of the machine. It is possible to notify the occurrence of a welding accident of the A contact using an alarm or the like.

(c) Since the occurrence of a welding accident at contact 3 can be accurately detected with only one switch, the number of switches required can be reduced by half compared to the case where two conventional switches are required, and the number of switches can be reduced by half. The detection circuit for welding accidents can be simplified.

(d) When two conventional switches are used, there is a drawback in that due to an error in the operating timing of both switches, even though no welding accident has occurred, they may malfunction and cause the machine to stop unnecessarily.

On the other hand, in the present invention, since only one switch is used, there is no error in the operation timing between the two switches, and the above-mentioned (conventional disadvantage of stopping the siege unnecessarily) is eliminated. can be eliminated.

(E) When two conventional switches are used If a welding accident occurs on one side switch at the same time, the same signal force will be output from both switches, so it will be mistakenly determined that no welding accident has occurred, and the machine will stop working. It has the disadvantage of running out of control.

In contrast, in the present invention, since only one switch is used, the machine runaway accident caused by the above-mentioned erroneous judgment can be completely eliminated.

<Embodiment 1> In FIGS. 1 and 2, reference numeral 1 is a box-shaped fixed frame, and a switch chamber 2 formed inside the frame has a
The contact 3 and the b contact 4 are placed opposite each other with an appropriate distance between them. a
Contact 3 is a fixed a contact 3 fixed to the right end surface of switch chamber 2.
A movable a-contact 3y faces the fixed a-contact 3X so as to be movable toward and away from the fixed a-contact 3X. The b contact 4 consists of a fixed contact 4x fixed to the left end surface of the switch chamber 2, and a movable contact 4y facing the fixed contact 4x so as to be able to freely approach and separate. Movable. Contact 3y and movable contact 4y are fixed a contact 3X, fixed b#, and point 4.
They are placed back to back with an appropriate distance between them and X.

An operating tool 8 is supported on the fixed frame 1 so as to be slidable forward and backward.
The protruding portion of this operating tool protrudes into the switch chamber 2.

The part of the operating tool 8 located inside the switch chamber 2 is formed into a bifurcated shape, and both rotating contacts 3y and 4y are provided in the groove-shaped space.
is installed.

A spring 5 for simultaneously closing both contacts is installed between the movable A contact 3y and the movable S contact 4y.
The spring length is such that the movable contacts 3y and 4y can be brought into sufficient elastic contact with the fixed contacts 3x and 1x in their free length. A return spring 6 is mounted between the movable a-contact 3y and the fixed frame 1, and the movable a-contact 3y is floated and supported by the elastic force of the return spring 6 and the elastic force of the spring 5 for closing both contacts simultaneously. There is. The movable contact 4y has a return spring 6 and a spring 5 for closing both contacts simultaneously.
It is pressed against the inner wall of the groove-shaped space of the operating tool 8 by the elastic force of.

Note that the tension of the spring S for simultaneously closing both contacts and the tension of the return spring 6 are approximately equal.

Reference numeral 10 in the figure is an insulating plate mounted between the movable contacts 3y, 4y and the springs 5, 6.

FIGS. 3 and 4 show an error detection state in which the a-contact of the above embodiment causes a welding accident and the a-contact 3 and b-contact 4 are turned on. An external detection device for detection is shown. This device is a fail safe circuit 12 built into a crankshaft top dead center stop circuit 11 of a mechanical press.

That is, as shown in FIG. 4, when the crankshaft 13 reaches the top dead center, the operating tool 8 falls into the valley 14X of the cam 14, the a contact 3 is turned off, and as shown in FIG. , relay switch L! is turned off, its normally open contact ρl is turned off, the solenoid 15 is demagnetized, the crankshaft drive clutch is disconnected, and the spring brake stops the crankshaft 13.

After this, when the foot switch 16 is repeatedly turned on, the crankshaft 13 is started, the operating tool 8 rides on the peak 14y of the cam 14, the b contact 4 is turned off, the a contact 3 is turned on, and the relay switch L1 Normally open contact ρ1 turns on, solenoid 15
is excited, the crankshaft 13 is started, and after the operating tool 8 climbs onto the peak 14y of the cam 14, the foot switch 1 is activated.
Even if 6 is turned off, the crankshaft 13 continues to rotate once.

If the a contact 3 is welded and remains on when the crankshaft 3 reaches the top dead center, the normally open contacts Q and 1 of the relay switch L1 remain on and the solenoid IS continues to be energized. Therefore, there is a risk that the crankshaft 13 will be rotated continuously. The fail safe circuit 12 operates to eliminate this danger.

Immediately, while the a contact 3 is held on, the operating tool 8 falls into the trough 14x of the cam 14, and the b contact 1 is turned on. Then, the fail-safe circuit 12 is energized, relay switch L7□ is turned on, and its normally closed contact ρ2 is turned off, demagnetizing the solenoid 15 and bringing the crankshaft 13 to an emergency stop.
The contact welding indicator lamp 17 lights up to indicate this.

Figure 5 shows a modified example of the present invention. The one shown in Figure 5 applies the spring force of the return spring 6 to the operating tool 8, and the A contact 3y
In the assembly of the movable contact, a spring 18 for absorbing this motion is attached to the tip wall of the hole, and the movable a contact 3y is supported floatingly by being held between two opposing springs.

In this case, as shown in FIG. 6, FIG. 7, or FIG. The a contact point 3y may be fixed with a bonding material 19.

, 4. Brief description of the drawings Fig. 1 is a longitudinal sectional front view showing an embodiment of the present invention, Fig. 2 is a
Fig. 3 shows an example of the use of the switch of the present invention (a circuit diagram for stopping the crankshaft at top dead center of a siege premata; Fig. 4 shows a diagram showing the operational relationship between the contact and the b contact). The operation diagram, FIGS. 5 to 8 are extracted views of main parts showing modified examples, and FIG. 9 is a longitudinal sectional front view showing seven conventional products.

1... Fixed frame, 3... A contact, 3X... Fixed A contact, :,! v,,,Kasen ha square 1,...to...h douchitsu, 44\...fixed contact,...1y...movable contact, 5...for both contacts to be closed at the same time Spring, 6...Return spring, 8...Working tool, 2()...Movement absorption spring.

Claims (1)

[Claims] 1. A contact 3 and a contact B...1 are placed opposite each other with an appropriate opening in the fixed frame 1, and the a contact 3 is a fixed a fixed to the fixed frame 1.
It consists of a contact 3X and a movable A contact 3y that faces the fixed A contact 3\ so that it can freely come into contact with and separate from it. The movable a contact 3y and the movable contact 4y are positioned back-to-back with an appropriate distance between the fixed 8 contact 3X and the fixed contact 4X, and the movable a A spring 5 for simultaneously closing both contacts, which presses the contact 3y toward the fixed A contact 3X side and presses the movable contact 4y toward the fixed contact 4X, is mounted across the movable A contact 3y and the movable contact 4y, An operation tool that pushes the movable contact 4y to the fixed a contact 4 and away from the a contact 3 side, and brings the movable a contact 3y into contact with the fixed a contact 3X via the movable contact 4y and a spring 5 for simultaneously closing both contacts. 8 is supported by the fixed frame 1 so as to be able to slide forward and backward in the direction of separation between the 8 contacts 3 and the b contacts 4, and the outer end of the operating tool 8 is made to protrude outside the end wall of the fixed frame 1 on the b contact side, and the operating tool 8 is movable. A contact 3y
A return spring 6 that pushes away the fixed A contact 3X from the B contact 4 side and brings the movable contact 4y into contact with the fixed contact 4\.
In a switch which is interposed between the movable A contact 3y and the fixed frame 1, a spring is arranged to face the spring 5 for closing both contacts simultaneously, and the movable A contact 3y is arranged between both springs. The movable a-contact 3y is placed in a floating support state with respect to the operating tool 8, and the free length of the spring S for simultaneously closing both contacts installed between both rotating contacts brings the movable a-contact 3y into contact with the fixed a-contact 3X. A slow-action non-wrap type contact Y switch 2 characterized in that the length of the movable contact 4y can be brought into contact with the fixed contact 4X, the slow-action type according to claim 1. A non-wrap type contact switch in which the spring disposed opposite to the spring 5 for simultaneously closing both contacts is a return spring 3, and a slow action non-wrap type contact switch according to claim 1, in which both contacts A spring placed opposite the spring 5 for simultaneous closing is the movable a contact 3.
A motion absorbing spring 18 attached between the y and the operating tool 8.