JPH03122927A - Limit switch - Google Patents

Abstract

PURPOSE:To facilitate grasp of the normal motion stroke range of an operating lever by actuating No.1 switch in the motion range in which rotation of the operating lever goes beyond the normal motion stroke range, and lighting up No.1 motion display element. CONSTITUTION:When an operating lever 10 rotates to the motion position OP, No.1 movable spring 25 driven by an operational lever 22 is put in motion to drive No.1 movable piece 26, so that No.1 switch 23 is put on to cause a light emitting diode 43 to emit red light. When the operating lever 10 rotates further, the rotation comes in the normal motion stroke range. At the lower limit OP1 No.2 switch 24 is put on the cause a light emitting diode 44 to emit green, and the first diode 43 will go off. When the operating lever 10 passes the upper limit OP2, No.2 switch 24 is put off, and the diode 44 will go off. This enables easy grasp of the normal motion stroke range.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to limit switches used in various production equipment, industrial robots, and the like.

<Prior art and its problems> In general, in a limit switch, when an object to be detected such as a workpiece rotates the operating lever to the operating position, a cam converts the displacement of the rotating shaft of the operating lever into a linear motion and switches the switch. A main plunger built into the case or head is driven, and an auxiliary plunger responds to this to turn on the basic switch mechanism. That is, when the operating lever is rotated from the free position to the operating position,
The operating lever is in the ON state, and the rotation range from the operating position to the operating limit position where the operating lever reaches the operating lever stop is ON.
A range of conditions.

By the way, since the ON state of the operating lever is unstable at the operating position or the operating limit position, generally, the operating lever is rotated from a rotational position (lower limit position) well beyond the operating position to a predetermined rotational position. The specifications are such that the range up to the angle (upper limit position) is the proper operating stroke range.

Conventionally, there is a device in which the light emitting diode is turned on at the lower limit position of the appropriate IF operation stroke of the operating lever, but since there is no indication of the upper limit position of the appropriate IF operation stroke, there is a risk of over-stroke. Yes, it is difficult to use.

<Object of the Invention> The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a limit switch that allows the stroke range of the operating lever to be easily grasped using two display elements.

<Configuration and Effects of the Invention> The limit switch according to the present invention has a head rotatably supporting an operating lever at one end of a switch case containing a built-in basic switch mechanism, and a head that rotatably supports the operating lever. axially move the plunger according to the rotation of the operating lever, and turn the basic switch mechanism.
In the device for turning on and off, first and second operation display elements -r connected in parallel to each other and emitting light in different colors, interposed between the parallel circuit of the operation display elements and the power supply side, and connected to the plunger. The first switch that responds and the first switch that responds
and a second switch connected in series to the operation display element of the controller and responsive to the plunger, and the first switch is turned on in the operating range in which the rotation of the operating lever deviates from the proper operating stroke range. The operation display element is turned on, and the second switch is turned on when the rotation of the operating lever is within a proper operation stroke range, thereby lighting up the second operation display element.

According to this invention, one of the first and second operation display elements, which emit light in different colors, is turned on when the operation lever is out of the proper operation stroke range, and the other operation display element is turned on when the operation lever is not properly operated. Since the light is turned on within the operating stroke range, it is possible to easily understand, by setting the operating lever to -11, whether the operating lever is under-stroked, over-stroked or is in an appropriate stroke state by the lighting display of these operation display elements.

<Explanation of Examples> Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are a partially cutaway side view and a front view, respectively, showing an example of a limit switch according to the present invention.

In the figure, reference numeral 1 denotes a switch case, which is comprised of a case body 3 having a basic switch mechanism storage recess 2 and a cover 5 for closing the recess opening 4 in an openable and closable manner. A basic switch mechanism 6 is accommodated in the recess 2, which is fitted with a screw 7.
is fixed.

On one end side of the switch case 1, there is a rotary shaft 8 that rotates once.
A head 9 which is rotatably supported is fixed. The rotating shaft 8
A base end 10a of an operating lever 10 is fastened to the outer end 8a of the operating lever 10 with a screw body II, and a roller 12 is rotatable via a shaft 13 at the tip Job of the operating lever 10. is supported by

A cam 14 is fixed to the inner end 8b of the rotary shaft 8 and converts rotational motion into linear motion. A cam 15 is interposed between the cam 14 and the inner wall of the head 9 and applies a return force to the operating lever 10. It is a return coil spring as a means of giving. Reference numeral 16 denotes a plunger that is held in the switch case 1 so as to be able to pivot, and includes a hollow plunger body 17, an auxiliary plunger I8 fitted into the plunger body 17, an auxiliary plunger 18, and a torsion of the plunger body 17. A buffer coil spring I9 interposed between the wall inner surface and the auxiliary plunger 1
8 and a push rod 20 for pushing and driving the operating rod 22 of the basic switch mechanism 6. 21 is a seal rubber.

The basic switch machine vt6 has a first switch 23 and a second switch 24, which are opened and closed by the operation rod 22, as shown in FIG. 5a. The first switch 23 includes a substantially W-shaped first movable spring 25 driven by an operating rod 22, a first six movable pieces 26 supported at both ends of the first movable spring 25, and It consists of movable contacts 27.28 fixed to both ends of the movable piece 26 of l, and normally open fixed contacts 29.30 and normally open fixed contacts 31.32 arranged opposite to these movable contacts 27.28, respectively. Also, the second switch 2
4 is a substantially W-shaped second Mf moving spring 33 driven by the operating rod 22, a second movable piece 34 supported at both ends of the second Movable contacts 35 and 36 are attached to both ends of the movable piece 34, and these movable contacts 35
Normally open fixed contacts 37.3 located opposite each other at ゜36
8 and normally open fixed contacts 39 and 40. 41 is a return spring for the operating rod 22.

The first movable spring 25 is set to operate faster than the second movable spring 33, so that +i
; Operating position i'W of the rotation stroke of the operating lever O
(O))), the first switch 23 is turned on, and the second switch 2 is turned on at the lower limit position (op,) of the proper operating stroke range.
4 is ONL, the upper limit position of the proper operating stroke range (o
p,), the step 22a of the operating rod 22 pushes the 0■ moving piece 34, and the second switch 24 turns OF1'.

A printed wiring board 42 is housed in the switch case 1, and has a plurality of wires that emit light in different colors. and a second operation display element, such as a red light emitting diode,
3 and a green light emitting diode 44 are set. A transparent window plate 46 is fitted into an opening 45 formed in the cover 5 corresponding to both the light emitting diodes 43 and 44.

Figure 3 is an electrical circuit diagram of the limit switch. In the figure, the first and second light emitting diodes 43
．． 44 constitutes a parallel circuit 47, and this parallel circuit 4
7 and one 48 of a pair of external terminals 48 and 49 connected to the power supply side.

50 is a resistor connected in series to the anode side of the first light emitting diode 43, and 51 is a resistor inserted between the parallel circuit 47 and the first switch 23. The second switch 24 is inserted on the cathode side of the second light emitting diode 44. 52 is a Zener diode for constant voltage.

Next, the operation of the above configuration will be explained.

F, ;llll! The operating lever 10 is in the free position () shown in Fig. 4.
'P), the first and second switches 23 and 24 are each in the 0-F state as shown in FIG. 5a.

When an object to be detected, such as a workpiece, hits the roller 12 of the operating lever 10, the operating lever 10 rotates about the rotating shaft 8 from its free position. Due to this rotational displacement of the operating lever 10,
The cam 14 rotates via the co-rotating shaft 8 against the spring force of the return coil spring 15, causing the plunger body 17 to move axially.

Due to this axial movement of the plunger body 17, the auxiliary plunger 1
8 responds via the buffer spring 19, and the operating lever l
At the position where O has rotated by a predetermined amount, the operating rod 22 of the basic switch mechanism 6 is pushed in by the suppressor 20 of the auxiliary plunger 18 (No. 11).

When the operating lever 10 rotates to the operating position (OP) shown in FIG. 4, the first movable spring 25 driven by the operating rod 22
operates and drives the first movable piece 26, so the first switch 23 is turned on as shown in FIG. 5b. When the first switch 23 is turned on, a current flows to the first light emitting diode 43, and the light emitting diode 43 emits red light.

-1- When the operating lever 10 further rotates from the operating position (OP), it reaches the proper operating stroke range. In this proper operating stroke range, the lower limit position (
op, ), the second movable piece 34 is driven by the operation of the second movable spring 33, so the second switch 24 is turned on as shown in FIG. 5C. O of this second switch 24
Due to N, a current flows to the second light emitting diode 44 side,
This light emitting diode 44 emits green light. At this time, since the current flowing to the first light emitting diode 43 is limited by the resistor 50, this light emitting diode 43 is turned off.

Therefore, the second light emitting diode 44 emits green light up to the upper limit (◇ position (op)) of the proper operating stroke range of the operating lever 10.

When the operating lever 10 passes the upper limit position (OPx) in the proper operating stroke range, the second movable piece 34 is forcibly driven in the return direction by the stepped portion 22a of the operating rod 22, as shown in FIG. 5d. Therefore, the second switch 24 is turned OFF.
As a result, the second light emitting diode 44 is no longer energized, and this light emitting diode 44 turns off. At the same time, current flows to the first light emitting diode 43 side, and this light emitting diode 43 turns off. It emits red light, which indicates that the operating lever 10 is maintained until the operating limit N (TTP) shown in Fig. 4. When the workpiece etc. leaves the operating lever lO,
This operating lever 10 returns to the free position ()'P) by the spring force of the return coil spring 15.

1-2 The light emitted from the first and second light emitting diodes 43 and 44 can be visually recognized through the window plate 46 in the cover 5. That is, if red light is emitted by lighting the first light emitting diode 43, the operation lever 10 is activated even in the operating state.
is either insufficient stroke or too much stroke, and the second
If the green light is emitted by the lighting of the light emitting diode 44, the operating lever 10 is within the proper operating stroke range, which can be easily recognized and is easy to mount.

In the above example, the actual light emitting diode 43 that emits red light and the second light emitting diode 44 that emits green light are used as operation display elements, but these may be diodes that emit light in other different colors. It is also possible to use a lamp as a substitute.

Furthermore, the configuration of the basic switch mechanism 6 is not limited to the example in item 1-1, and can be modified.

[Brief explanation of drawings]

1 and 2 are a partially cutaway side view and a front view, respectively, showing an example of a limit switch according to the present invention, FIG. 3 is an electric circuit diagram of the limit switch, and FIG. 4 is an operating lever of the limit switch. Figures 5a and 5 show the relationship between the operating stroke of the light emitting diode and the light emitting display of the light emitting diode.
Fig. b, Fig. 50, and Fig. 5d are explanatory diagrams of the operation of the limit switch corresponding to the operating stroke of the operating lever. 1... Switch case, 6... Basic switch mechanism,
9... Head, 10... Operation lever 16... Plunger, 23... First switch, 24... Second switch, 43... First operation display element, 44... Second Operation display element. Figure 2 Figure 5c Figure 3 Figure 5b Figure 5d

Claims (1)

[Claims] (1) A head with a rotatably supported operating lever is fixed to one end of a switch case containing a basic switch mechanism, and the plunger held in the switch case or head is rotated in response to the rotation of the operating lever. In a device that turns the basic switch mechanism ON/OFF by moving the shaft,
first and second operation display elements connected in parallel to each other and emitting light in different colors; a first switch interposed between the parallel circuit of the operation display elements and the power supply side and responsive to the plunger; a second switch connected in series to the first operation display element and responsive to the plunger; the first switch is turned ON in an operation range in which the rotation of the operation lever deviates from the proper operation stroke range; A limit switch characterized in that a first operation display element is turned on, and a second switch is turned on when the rotation of the operating lever is within a proper operation stroke range, so that the second operation display element is turned on.