JPH0447861Y2 - - Google Patents

Description

[Detailed description of the invention] <<Industrial Application Field>> This invention relates to a limit switch used for object detection, etc.

<<Prior Art>> A limit switch includes a switch box housing a built-in switch and an actuator for operating the built-in switch. and,
This limit switch is attached to a belt conveyor line, etc., and when a subject on the conveyor collides with it, it activates a built-in switch via an actuator, and outputs the on/off signal of the switch to the outside through a lead wire. There is a structure in which a light emitting element such as a lamp is turned on and off in accordance with the on/off operation of a switch, and is displayed externally.

This structure is provided with an opening necessary for housing the built-in switch and for connecting an external lead wire to the built-in switch. After the parts are stored and the connection work is completed, the opening is sealed with a cover and screwed.

[Problems that the invention aims to solve] In a structure where the opening is sealed with a cover, if the seal is not sufficiently sealed, water or oil may seep into the interior during use, resulting in malfunction. Cause. Therefore, in order to obtain a sufficient sealing effect, in the conventional structure, for example, if only two diagonal corners are screwed together, the other diagonal corner parts rise up, making it impossible to achieve a sufficient seal. The screws were tightened at each diagonal corner, that is, at four locations. Therefore, there were disadvantages such as poor workability and increased costs.

Therefore, the object of this invention is to provide a limit switch which can provide a more sufficient sealing effect with a cover using fewer screws.

<Means for Solving the Problems> The limit switch according to this invention includes a switch box housing a built-in switch, a cover screwed to the switch box, and an actuator provided on the switch box to operate the built-in switch. A limit switch comprising: a protruding wall provided at a cover mounting portion of the switch box; the cover having a groove for receiving the protruding wall; and a groove corresponding to an outer surface of the protruding wall. The inner surface of the groove is formed of an inclined surface, and an elastic sealing member is sandwiched between the outer surface of the protruding wall and the inner surface of the groove.

《Example》 Figures 1 to 5 show one embodiment of the limit switch according to the present invention, in which Figure 1 is a plan view thereof, Figure 2 is a side view taken along the line - in Figure 1, and Figure 5 is a side view of the limit switch according to the present invention. 3
The figure is a cross-sectional view taken along the - line in Figure 1, and Figure 4 is a cross-sectional view of Figure 1.
Fig. 5 is a partially cutaway plan view with the cover removed and shown partially cut away.
FIG.

In the figure, a limit switch 1 has a built-in switch 3 housed in a rectangular switch box 2, and is also integrally equipped with an actuator for operating a push button 42 of this built-in switch 3.
Moreover, the switching state of the built-in switch 3 is displayed by a display light emitting diode 16.

The switch box 2 has a storage recess 5 that stores the built-in switch 3 and a plunger mounting hole 7 that receives the movable plunger 6. The storage recess 5 and the movable plunger 6 are separated by a partition 8, but the plunger mounting hole A through hole 9 communicating with the storage recess 5 and the plunger mounting hole 7 is formed at a position corresponding to the axial center of the plunger 7 . The through hole 9 has a rear end 3 of the auxiliary plunger 31 in the plunger mounting hole 9.
1A is slidably protruded, and the push button 42 of the built-in switch 3 is housed in the storage recess 5.
is arranged at a position corresponding to the through hole 9, and the storage recess 5 is moved from the through hole 9 by sliding displacement of the auxiliary plunger 31.
The push button 42 is pressed by the rear end 31A of the auxiliary plunger 31 that is projected inward.

This auxiliary plunger 31 has plunger mounting hole 9
It is slidably supported by a holder 33 fixed to the bottom of the housing via a rubber seal packing 32. Further, a spring seat 34 is loosely fitted into the front end of the auxiliary plunger 31, and compression coil springs 35 and 36 are interposed between the spring seat 34 and the holder 33 and between the intermediate step portion 31B of the auxiliary plunger 31, respectively. has been done. And on the auxiliary plunger 31 and on the spring seat 3
A locking ring 50 is attached to the front end of the holder 33 to prevent the spring seat 34 from slipping out from the auxiliary plunger 31 during assembly, and a collar member 51 that comes into contact with the rear part 33A of the holder 33 and the auxiliary plunger are attached to the rear end side. A flange-shaped stopper 52 is fixed thereto for regulating the amount of rearward displacement of the auxiliary plunger 31, that is, the amount by which the rear end portion 31A of the auxiliary plunger 31 protrudes into the storage recess 5. Another holder 29 is fixed to the entrance of the plunger mounting hole 7 via a cover 28, and the movable plunger 6 is slidably supported on this holder 29. A spring seat 34 loosely fitted to the front end of the auxiliary plunger 31 is abutted and locked on the step 6A in the movable plunger 6, and its lowermost flange 6B is caught on the lowermost end of the holder 29, allowing it to be pulled out. A stop has been applied. Further, a roller 37 is rotatably attached to the tip end 6C of the movable plunger 6 via a roller shaft 38.

That is, the movable plunger 6, the plunger mounting hole 7, the holder 29, the auxiliary plunger 31,
The actuator is composed of parts such as a seal packing 32, a holder 33, a spring seat 34, compression coil springs 35 and 36, a roller 37, and a roller shaft 38.

In this actuator, when no pressing force is applied to the roller 37 from the outside, the auxiliary plunger 31 moves together with the spring seat 34 due to the urging force of the compression coil springs 35 and 36, and the flange portion 6B of the movable plunger 6 moves toward the front end. Holder 28
It is placed in a displaced state until it is positioned in contact with the lowest end of. That is, in this state, the rear end portion 31A of the auxiliary plunger 31 is retracted from the storage recess 5, and the movable plunger 6 is in a state of largely protruding from the front end. When a pressing force is applied to the roller 37 from the outside, the movable plunger 6 slides toward the inside of the plunger mounting hole 7, and the movable plunger 6 connects the compression coil spring 35 on the outside and the inside through the spring seat 34. The compression coil spring 36 is pressed. At this time, the inner compression coil spring 36 presses the auxiliary plunger 31 toward the rear end, and the auxiliary plunger 31 slides toward the rear end until the stopper 52 is positioned in contact with the bulkhead 8, and the rear end 31A It will be in a state of protruding into the storage recess 5. Then, the push button 42 of the built-in switch 3 is pressed down using the rear end 31A. In this push-down operation, by positioning the stopper 52 and the bulkhead 8 in contact with each other, the push button 42 is given a substantially minimum amount of displacement that requires a contact switching operation in the built-in switch 3, and The life of the built-in switch 3 is improved by reducing the load applied to the members necessary for switching the contacts. When the movable plunger 6 is further pressed toward the rear end in a state where the stopper 52 and the partition wall 8 are positioned in contact with each other, the auxiliary plunger 31 and the spring seat 34 are placed in a loosely fitting relationship. Therefore, only the spring seat 34 is slidably displaced together with the movable plunger 6 toward the rear end side. When the external pressing force on the roller 37 is released again, the movable plunger 6, spring seat 34, and auxiliary plunger 31 are displaced toward the front end by the return force of the compression coil springs 35 and 36, returning to the initial state.

The switch box 2 with the actuator attached as described above has a mounting hole 1 cut through it vertically to attach the limit switch 1 to other equipment.
0 is formed on both sides, and an L-shaped protrusion 11 is formed on the upper surface of the mounting hole 10 at a position surrounding a part of the mounting hole 10.
is provided, and a positioning recess 12, also L-shaped, is formed on its lower surface for receiving and positioning the protrusion 11 of the adjacent limit switch 1 when a plurality of limit switches 1 are mounted one on top of the other. Furthermore, a cylindrical portion 15 and a hole 17 are provided on the rear surface of the switch box 2. Cylindrical part 1
5 is the external lead wire 1 attached to the screw formed on its outer periphery.
A coupling nut (not shown) of the insulating pipe 14 containing the insulating pipes 3A, 13B, and 13C is screwed and fixed. The light emitting diode 16 is housed in the hole 17 from inside the housing recess 5 with its base 16A positioned in contact with the inner wall of the housing recess 5. and,
The outer side of the hole 17 is formed in a tapered shape with an inclined surface 17A that widens outward.
By forming the inclined surface 17A, the amount by which the light emitting diode 16 protrudes from the rear end surface 2A of the switchbox 2 is effectively reduced, thereby preventing damage due to collision with an external member, and at the same time preventing the light emitting diode 16 from being exposed to the outside. A large irradiation area contributing to the irradiation of the light emitting diode 16 is obtained, and the diffused light irradiated from the light emitting diode 16 is focused on the inclined surface 17A, thereby improving the visibility of the irradiation state.

Further, the upper surface 18 of the switch box 2 where the storage recess 5 is formed is formed to be one step lower than the upper surface of the region where the plunger mounting hole 7 is provided. On this upper surface 18, a continuous projecting wall 20 and two screw holes 21 are formed so as to surround the opening periphery of the storage recess 5, and the two screw holes 21
are located diagonally to each other. This upper surface 18 is covered with a cover 4 after the built-in switch 3 is housed in the housing recess 5. The cover 4 has a groove 22 on its inner surface that corresponds to the protruding wall 20 of the switchbox 2.
is formed. Further, as shown in an enlarged view in FIG. 10, one side wall of the groove 22 has an inclined surface 2
3, a rubber sealing 24 is sandwiched between this inclined surface 23 and the protruding wall 20 on the upper surface 18 side, and the other side wall 25 of the groove 22 is in contact with the inner wall 26 of the storage recess 5. The cover 4 is sealed so as to be in contact with each other. The cover 4 attached to the upper surface 18 in this manner is fixed by tightening screws 27 that are screwed into the screw holes 21 through mounting holes formed corresponding to the two screw holes 21 formed on the upper surface 18. be done. The pressing force due to tightening of this screw 27 is applied by the inclined surface 23.
and in a direction perpendicular to the inclined surface 23, and press the sealing 24 evenly to prevent water from entering from the outside. In addition, in this structure, the other side wall 25 of the cover 4 is the inner wall 2 of the storage recess 5.
6, so that even if the screws 27 are only screwed into the two screw holes 21, the other diagonal corners where the screws are not tightened are connected to the other side wall 25 and the storage recess. 5 is prevented from floating due to its contact with the inner wall 26,
The sealing 24 is pressed evenly over the entire concave groove 22, and a stronger seal can be achieved with less screw tightening, resulting in a structure that aims to reduce the number of man-hours required for screw tightening work.

Next, the built-in switch 3 housed in the housing recess 5 of the switch box 2 has a structure as shown in FIGS. 7 to 9. The built-in switch 3 has a switch section 48 and a terminal block 49 provided at its rear end, as roughly divided by dotted lines in FIG.
It has a structure in which a light emitting diode 16 is attached and a printed wiring circuit section 53 for controlling light emission, and these are integrated into a unit by a case body 41 made of synthetic resin.

The switch part 48 has the push button 42 made of synthetic resin and a pair of fixed contact pieces 43 and 44 made of a conductive metal material in a switch member storage recess 54 formed in the case body 41. Fixed lead piece 45 and movable contact piece 46 made of metal material
This structure incorporates a return leaf spring 47 and the like.

The case body 41 has holes 55 and 56 into which positioning pins (not shown) protruding from the bottom of the storage recess 5 of the switch box 2 are inserted, respectively.
In addition, external lead wires 13A, 13B, 1 are provided on the top side.
A portion for connecting a crimp terminal 57 fixed at the tip of 3C is provided, and a switch member storage recess 5 is provided on the lower surface side.
4 and a printed wiring circuit section 53 are respectively provided. In the terminal block 49, a cylindrical member 58 made of a conductive metal material with exposed ends on the upper and lower surfaces is insert-molded in the case body 41, and a crimp terminal 57 is formed on the inner surface of the cylindrical member 58. A female thread is formed to which a screw 59 for fixing is attached. The cylindrical member 58 may be integrally formed by burring to protrude from the connecting pieces 43A, 44A, 45A of the fixed contact pieces 43, 44 and the lead piece 45, which will be described later.

The push button 42 pushed down by the rear end 31A of the auxiliary plunger 31 is slidably received in a groove 60 formed in the case body 41, and one end of the push button 42 is pushed down by the rear end 31A of the auxiliary plunger 31.
A protruding portion 42A is formed at the other end of the protruding portion 42A, which protrudes at a position corresponding to A, and whose protruding amount is regulated by contact with the stepped portion 60A of the groove 60.

The fixed lead piece 45 includes a connecting piece 45A that is punched out of a metal plate and bent, a fixing part 45B that is bent upward at a substantially right angle to the connecting piece 45A, and a connecting piece 45B that is bent upward from the fixing part 45B. Further, a supporting portion 45C bent upward into a substantially L-shape is integrally formed. This fixed lead piece 45 is a fixed part 45B.
is press-fitted and fixed into the groove 61 formed in the case body 41, the support part 45C is arranged in the housing recess 54, and the connecting piece part 45A is inserted into the protrusion formed at the terminal block 49 on the lower surface of the case body 41. It is arranged in a recess 66 surrounded by partition walls 62 and 63. Furthermore, two protruding walls 61A are formed on one side wall of the groove 61 to which the fixing portion 45B is fixed. The dimension between this protruding wall 61A and the other side wall is slightly smaller than the plate thickness of the fixing part 45B, and therefore, the fixing part 45B press-fitted into the groove 61 is in pressure contact between the protruding wall 61A and the other side wall. It is firmly fixed by clamping. Further, the connecting piece portion 45A disposed within the recess 66 is provided with a hole 45E at a position corresponding to the cylindrical member 58 located within the recess 66, and one end of the cylindrical member 58 is inserted into the hole 45E. After insertion and locking, a part of the cylindrical member 58 that protrudes through the hole 45E is caulked to connect the fixed lead piece 45 and the cylindrical member 58.
An electrical connection is made with the A hole 45F for inserting and connecting a lead wire is formed in a portion of the connecting piece portion 45A that extends further downward, and the supporting portion 4
5C is provided with protruding pieces 45G and 45H formed by cutting and raising a part of the protruding piece 5C further upward.

The movable contact piece 46 is formed of a conductive thin plate with sufficient elasticity, and has a contact part 46D in the middle thereof, which the lower end of the push button 42 contacts, and two elongated holes 46A on both sides of the contact part 46D. , 46B are formed. One end of the movable contact piece 46 is abutted and engaged with the engagement groove 45I formed in the protrusion 45G of the fixed lead piece 45 disposed in the elongated hole 46A, and the other end provided with the movable contact piece 67 is It is held by a return spring 47 disposed between the fixed lead piece 45 and the movable contact piece 46. When this return spring 47 is assembled, it is bent inward as a whole in a spring-charged state, and one end is abutted and engaged with the engagement groove 45J formed in the protrusion 45H of the fixed lead piece 45, and the other end is engaged with the engagement groove 45J formed in the elongated hole. It is abutted and locked in an engagement recess 46C formed in 46B. The spring charge force of the return spring 47 urges the movable contact piece 46 to the left in FIG. 8 to maintain the abutting connection between the movable contact piece 46 and the engagement groove 45I.

The fixed contact pieces 43 and 44 are connection pieces 43A and 4 which are respectively punched out and bent from a single metal plate.
4A, and fixed parts 43B and 44B bent upward at a substantially right angle to the connecting pieces 43A and 44A.
and contact portions 43C, 44C which are bent further upward from the fixing portions 43B, 44B into a substantially L-shape are integrally formed. Each fixed contact piece 43 and 44
are two protruding walls 61A similar to the fixed lead piece 45.
The fixing portions 43 are located in the grooves 61 in which the fixing portions 43 are formed.
B and 44B are press-fitted and fixed. The contact portion 43C of the fixed contact piece 43 is located above the movable contact piece 46.
Further, the contact portion 44C of the fixed contact piece 44 is connected to the movable contact piece 46.
The fixed contacts 6 are arranged to extend below the movable contact piece 46 and are located opposite to the movable contact 67 of the movable contact piece 46.
8 and 69 are provided respectively. Further, the connecting piece portion 43A of the fixed contact piece 43 is disposed in a recess 70 surrounded by projecting partition walls 64 and 65 formed at the terminal block 49 on the lower surface of the case body 41.
The connecting piece 44A of the fixed contact piece 44 is disposed in a recess 71 surrounded by projecting partition walls 63 and 64 formed at the terminal block 49 on the lower surface of the case body 41. Each of the connection pieces 43A and 44A disposed in the recesses 70 and 71 is provided with holes 43E and 44E at positions corresponding to the cylindrical member 58 located in the recesses 70 and 71, respectively, and the fixed lead pieces 45, electrical connection between each cylindrical member 58 and the fixed contact pieces 43, 44 is achieved by caulking a portion of the cylindrical member 58 that protrudes through the holes 43E, 44E. And the connection piece part 43A,
Holes 43F and 44F for inserting and connecting lead wires are formed in the portions 44A extending further downward, respectively.

In the switch portion 48 formed in this manner, the movable contact piece 67 and the fixed contact 68 are brought into contact with each other by the biasing force of the return spring 47, and the movable contact 67 and the fixed contact 69 are normally held in a separated state. There is. Then, by operating the actuator described above, the auxiliary plunger 31 is displaced rearward, and the push button 4 is pressed at the rear end 31A.
2 is pushed down, the movable contact piece 46 in contact with the push button 42 is pivoted downward about the abutment engagement portion with the engagement groove 45I as a fulcrum. When this rotational displacement reaches a predetermined amount, the return spring 47 moves the movable contact piece 4
6 is rapidly rotated downward to switch the contact of the movable contact 67 from the fixed contact 68 to the fixed contact 69. Then, by operating the actuator, the auxiliary plunger 31 is again displaced forward and the push button 4 is pressed.
2 is released and the movable contact piece 46 rotates upward again, the return spring 47 rapidly rotates the movable contact piece 46 upward to remove the contact of the movable contact 67 from the fixed contact 69. Switching to contact with the fixed contact 68. That is, the circuit switching of the switch is performed. Regarding this switch section 48, as mentioned above, the switching operation of the movable contact piece 46, especially the fixed contact 6
8 to the fixed contact 69, after the movable contact piece 46 exceeds the dead center of the return spring 47, the return spring 4
The switching is maintained by a biasing force of 7. Therefore, the amount by which the push button 42 is pressed may be limited to a position where the movable contact piece 46 exceeds the dead center of the return spring 47. For this reason, the arrangement position of the stopper 52 formed on the auxiliary plunger 31 is such that the movable contact piece 46 is
The rear end portion 31A is set so as to protrude into the storage recess 5 as far as the push button 42 can be pressed until it slightly exceeds the dead center of the push button 7, thereby preventing excessive load from being applied to the movable contact piece 46, etc. We are trying to improve the lifespan by doing so.

The switch part 48, in which the switch components are assembled in the switch member storage recess 54 as described above, is hermetically sealed by a switch cover 72 that is covered from the lower surface thereof. This switch cover 72 has holes 73 formed at positions corresponding to the protruding walls 63 and 64, and is attached to the case body 41 by fitting and press-fitting the protruding walls 63 and 64 into the holes 73. Fixed.

Further, the printed wiring circuit section 53, which is attached to the switch case 41 to form a unit, has a printed wiring board 73 on which a wiring pattern is formed on the case body 41 fixed thereto. This printed wiring board 73 has a hole 95 formed in the case body 41.
A pair of insertion terminal holes 75 into which the terminals 16B of the light emitting diode 16 protruding through are inserted and connected.
, fixed connection pieces 43 and 44 and fixed lead piece 45
Insertion terminal holes 77A, 77B, 77C into which lead wires 76A, 76B, 76C connecting between the connection piece parts 43A, 44A, 45A are inserted and connected;
Insertion terminal holes 80A, 80B, and 80C are formed into which terminals 78A, 78B, 79A, and 79B of circuit switching plugs 78 and 79 shown in detail in FIG. 6 are inserted and connected. One of the insertion terminal holes 75 is connected to the insertion terminal holes 80C and 77C by lines 82, 83, and 84 through the one-way rectifier 81, and the other is connected to the insertion terminal through the resistor 85, one-way rectifier, and 81. Lines 86, 8 in holes 80C and 77C
3.81 is connected. In addition, the insertion terminal hole 8
0A and 77A are lines 87, insertion terminal holes 80B
and 77B are connected by line 88. The printed wiring board 73 has a fixed contact piece 43 at one end,
The other end is inserted into the holes 43F and 44F of 44, and the terminal hole 77
A, 77B, one end of which is inserted into the hole 45F of the fixed lead piece 45, the other end of which is inserted into the insertion terminal hole 77C, and the lead wire 76A is fixed by soldering.
76B, 76C are attached to each fixed contact piece 43,
44 and a fixed lead piece 45, electrical connection is made. In addition, insertion terminal holes 80A, 80B, 80C
As shown in FIG. 6, the circuit switching plugs 78 and 79 attached to the
substantially U-shaped conducting wires 78C and 79C, each having
are insert-molded into synthetic resin cases 78D and 79D. In the circuit switching plugs 78 and 79, terminals 78A and 79A protrude from the same center, and terminals 78B and 79B protrude from opposite positions. and,
When this switching plug 78 is attached to the printed wiring board 73, the terminal 78A is inserted into the insertion terminal hole 80.
In C, the terminals 78B are inserted into the insertion terminal holes 80B to short-circuit the lines 88 and 83, and in the normal state when the contacts 67 and 68 are short-circuited, the light emitting diode 16 does not emit light, and the contacts 67 and 69 It can be made to emit light when there is a short circuit. Also, the switching plug 7 can be replaced with the switching plug 78.
9 is installed, the terminal 79A is inserted into the insertion terminal hole 80C, the terminal 79B is inserted into the insertion end hole 80A, and the lines 87 and 83 are short-circuited, and the contacts 67 and 68 are short-circuited. The light emitting diode 16 may emit light at times, and may be turned off when the contacts 67 and 69 are short-circuited. That is, the switching plug 78 is normally used to turn off the light, and the switching plug 79 is used to normally turn on the light.

By selecting the switching plugs 78 and 79 to be attached to the printed wiring board 73 in this manner, the printed wiring board 73 can be used in common. Note that it is not necessarily necessary to prepare two switching plugs 78 and 79 constituting this circuit switching means.
Lines 87 and 88 may be switched to line 83 by replacing the same plug.

Next, as shown in detail in FIG. 7, the connection terminal section 49 that is attached to the case body 41 and formed into a unit is attached to the upper surface side of the switch case 41.
That is, the external lead wires 13A, 1 are connected to the part of the switch box 2 facing the opening in the storage recess 5.
It has connection parts with 3B and 13C. One end of the cylindrical member 58 insert-molded together with the case body 41 is exposed on the upper surface side of the case body 41, and these are partitioned by a projecting wall 89 protruding from the upper surface of the case body 41. Separated. The case body 41 is formed at a position corresponding to the inner opening 15A of the hollow cylindrical portion 15 formed on the rear surface of the switch box 2 so as to be downwardly directed toward the inner opening 15A of the hollow cylindrical portion 15. A sloped surface 90 is provided. This inclined surface 90 is used to attach the crimp terminals 57 fixed to the tips of the external lead wires 13A, 13B, and 13C that are inserted from the outside of the switch box 2 through the hollow cylindrical portion 15 into the storage recess 5. 90 to lead upward, and external lead wires 13A, 13B, 13
To facilitate the insertion work of C.

In this way, with the case body 41 as a base, the switch part 48, the terminal block 49, the printed wiring circuit part 5
The built-in switch 3, which is made into a unit, is positioned and stored in the storage recess 5 of the switch box 2 using the positioning pin in the storage recess 5, prior to connection with the external lead wires 13A, 13B, and 13C. Ru. Then, external lead wires 13A, 13B,
13C is inserted through the hollow cylinder part 15, and at that time, the external lead wires 13A, 13 are inserted upwardly on the inclined surface 90.
The crimp terminals 57 at the tips of B and 13C are guided. The crimp terminal 57 guided upward is connected to the cylindrical member 5.
After interposing a metal ring washer 91 between 8 and 8,
The crimp terminal 57 is firmly fixed to the terminal block 49 via the crimp terminal 57 by a screw 59 screwed into the inner female threaded portion of the cylindrical member 58 through the hole 57A of the crimp terminal 57. The connection of the external lead wires 13A, 13B, and 13C via the crimp terminals 57 is all performed through the opening in the storage recess 5 in the switchbox 2. Therefore, the built-in switch 3 is connected to an external power source via external lead wires 13A, 13B, and 13C.

In the above embodiment, a light emitting diode was used as the light emitting element, but an incandescent lamp or the like may also be used, and the mounting position is not limited to the rear end face, but may be installed at any position as necessary. You may choose.

<<Effects of the invention>> As described above, the limit switch according to this invention has a protruding wall in the cover mounting part of the switch box, a recessed groove for receiving the protruding wall of the cover mounting part in the cover, and a protruding wall in the cover mounting part. The inner wall surface of the groove is formed with a tapered surface that corresponds to the outer surface of the wall.
Since the elastic sealing is interposed between the outer surface of the protruding wall and the inner wall surface of the concave groove and the screw is fastened, the pressing force due to the tightening of the screw is applied to the direction along this slope and perpendicular to the slope due to the slope. The sealing material is dispersed in different directions, and the sealing material is evenly pressed to obtain a more sufficient sealing effect. Moreover, in order for the inner wall surface of the concave groove corresponding to the inner surface of the protruding wall to come into contact with the inner surface, even if the inner wall surface is only screwed at one diagonal position, for example, other There is no inconvenience such as the diagonal corners lifting up, a sufficient sealing effect can be obtained with a small number of screws, and costs can be reduced by reducing the number of man-hours.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of a limit switch according to the present invention, FIG. 2 is a side view taken along the - line in FIG. 1, and FIG. 3 is a sectional view taken along the - line in FIG. Figure 4 is a partially cutaway plan view of Figure 1 with the cover removed, and Figure 5 is a cross-sectional view taken along the - line arrow in Figure 2. An example of the socket shown in the figure is shown in Fig. 6A. Fig. 6A is a side view of the normally closed socket, Fig. 6B is a plan view of Fig. 6A, and Fig. 6C is a side view of the normally open socket. Side view, Fig. 6D is a plan view of Fig. 6C, Fig. 7 is a plan view of Fig. 1
An enlarged perspective view showing the built-in switch shown in Figures 5 through 5 and the external lead terminals connected to this switch, and Figure 8 is an enlarged perspective view of the built-in switch shown in Figure 7, viewed from the outside with the bottom cover removed. 9 is an exploded perspective view of the built-in switch shown in FIG. 7, and FIG. 10 is an enlarged sectional view of the cover corner portion of FIG. 3. 1...Limit switch, 2...Switch box, 3...Built-in switch, 4...Cover, 5...
...Storage recess, 6...Movable plunger, 13A, 1
3B, 13C... External lead wire, 15... Cylindrical part serving as a lead wire insertion port, 16... Light emitting diode serving as a light emitting element, 17... Through hole for light emitting diode, 17A... Inclined surface of hole, 20 ...Protruding wall, 2
2... Concave groove, 23... Inclined surface within the concave groove, 24...
Sealing, 31... Auxiliary plunger, 41...
Case body, 43, 44... fixed contact piece, 45...
Fixed lead piece, 46...Movable contact piece, 47...Return plate spring, 48...Switch part, 49...Terminal block, 52...Stopper, 53...Printed wiring circuit, 54...Switch member storage recess ,78,7
9...Circuit switching plug constituting switching means, 90
...Slope surface.

Claims (1)

[Scope of utility model registration request] A switch box that houses a built-in switch,
A limit switch comprising: a cover screwed to the switchbox; and an actuator provided on the switchbox and actuating the built-in switch; the cover has a groove for receiving the protruding wall;
The inner surface of the groove corresponding to the outer surface of the projecting wall is formed of an inclined surface, and an elastic sealing is interposed between the outer surface of the projecting wall and the inner surface of the groove. A limit switch that is characterized by: