GB2108322A - Push-button switches - Google Patents

Abstract

In a push-button switch having a rocking contact plate 8; an operating slider 2; a pivotable driving member 5 which is held in pressed contact with the rocking plate 8; and a coiled spring 11 which is arranged in the driving member 5 and whose upper end 11a abuts on an inner surface of a top plate 1a of the switch case 1; the rocking plate 8 being rocked by the driving member Sin response to the sliding of the slider 2 so as to bring stationary 9a, 10a and movable 8a, 8b contacts into or out of electrical contact; the improvement comprises the fact that the upper end 11a of the coiled spring 11 has a diameter larger than the other part thereof, so the inner surface of the top plate 1a is difficult to damage during sliding of the spring 11 thereover. <IMAGE>

Description

SPECIFICATION Switch The present invention relates to a switch which includes a rocking contact of light switching operation touch.

Heretofore, there has been a push-button switch of the rocking contact system shown by a vertical sectional view in Figure 1. This push-button switch has a slider 2 slideably disposed within a case 1 of an insulator. The slider 2 is urged by a spring 3 in the direction (X-direction) in which an operating arm 2a protrudes out of the case 1. The upper surface of the slider 2 is formed with a heart-shaped lock groove 2b, in which one end 4a of a U-shaped lock pin 4 is inserted. Owing to the lock pin 4 and the lock groove 2b, the slider 2 is locked in a position where it has been pushed in the direction of arrow Y, and when further pushed in the direction of arrow Y, the slider 2 is unlocked to revert into the state of Figure 1.In addition, pins 5a for supporting both the sides of a driving member 5 are carried on both the lateral surfaces of the case 1, so that the driving member 5 can turn about the supporting pins 5a. The driving member 5 can also move up and down within the case 1. This driving member 5 is urged downward by a spring 6. Under the state shown in Figure 1, the driving member 5 depresses the left end of a rocking plate 8 which rocks in the bottom part of the case 1 with a supporting terminal 7 as a fulcrum, thereby to hold a contact 8a in touch with a stationary contact 9a located at the upper end of a stationary terminal 9. When the slider 2 is pushed in the direction of arrow Y, the driving member 5 is turned counterclockwise about the supporting pins 5a until the tip 5b of the driving member 5 abuts on the right side of the rocking plase 8.Then, the right side part of the rocking plate 8 is depressed by the force of the spring 6, and the rocking plate 8 is turned in seesaw fashion with the supporting terminal 7 as a fulcrum, so that a contact 8b disposed at the right end part of the rocking plate 8 comes into touch with a contact 10a located at the upper end of a stationary terminal 10. That is, the slider 2 is moved in the Y-direction by pushing the operating arm 2a, so as to be locked by the lock pin 4 and the lock groove 2b. Thus, the contacts 8b and 1 Oa touch to render the supporting terminal 7 and the stationary terminal 10 electrically conducting.Further, when the operating arm 2a is pushed in the Y-direction again so as to release the locking and to return the slider 2 in the direction of arrow X, the contacts 8a and 9a touch to render the supporting terminal 7 and the stationary terminal 9 electrically conducting, as illustrated in Figure 1.

In the above operation of the push-button switch, the siding operation of the slider 2 accompanies the turning of the driving member 5 with the supporting pins 5a as the fulcrum. At this time, the spring 6 extended in the driving member 5 from above receives a lateral force with the turning of the driving member 5. Accordingly, the upper end of the spring 6 slides along the inner surface of the top plate 1 a of the case 1 in accordance with the turning of the driving member 5. This leads to the disadvantage that the inner surface of the top plate 1 a damages as the number of times of the switching operations increases. Moreover, when the slider 2 is suddenly slidden, the upper end of the spring 6 cannot follow up the sliding and does slide on the inner surface of the top plate 1 a in some cases.At this time, the spring 6 bends in the shape of letter V lying sideways, and stresses concentrate locally, so that the spring 6 is liable to break down. Even in a case where the spring 6 does not break down immediately, fatigue is accumulated due to the bending, and then, the upper end of the spring 6 becomes increasingly difficult of following up the turning of the driving member 5. In some cases, the spring 6 falls off from the driving member 5 as the turning of the latter.

The present invention eliminates the problem of the fatigue of the spring in the prior-art switch, and has for its object to provide a switch in which the fatigue of a spring during manipulation is relieved so as to ensure a reliable operation.

The present invention is characterized in that the upper end (11a) of a spring (11) during a driving member (5) is wound to be larger in diameter than the other part thereof, and that the upper end of the larger diameter is caused to abut on the inner surface ofthetop plate (lea) of a case (1).

Figure lisa vertical sectional view showing a prior-art switch; Figure 2 is a vertical sectional view showing a switch according to the present invention; and Figure 3 is an exploded perspective view of the switch according to the present invention.

Hereunder, an embodiment of the present invention will be described with reference to Figures 2 and 3.

Various components other Th3n a spring 11 are the same as shown in Figure 1. The case 1 is molded of plastics in the shape of a box. An opening loins defined in the front face of a fore projection 1 b. On the bottom surface of the opening 1 c, there is formed a protrusion id, the top surface of which is formed with a supporting hole le. The supporting hole 1 e serves to support the end part 4b of the U-shaped lock pin 4. The inner surfaces of both the side plates of the case 1 are formed with a set of supporting recesses if and 1g and another set of supporting recesses ih and 1 i.The supporting terminal 7 and the pair of stationary terminals 9 and 10 arranged on both the sides thereof are planted in the bottom of the case 1 in such a manner that the lower end parts of the respective terminals jut out below the case 1. The upper end of the supporting terminal 7 is formed with a notch 7a, by which the central part of the rocking plate 8 is rockably supported. All of the supporting terminal 7, the stationary terminals 9 and 10 and the rocking plate 8 are molded of an electrically conductive material.

The slider 2 to be furnished in the case 1 is so set that the operating arm 2a is protruded from the opening Ic, and that lugs 2c and 2d which are formed on both the sides of the rear part of the slider 2 are inserted in guide grooves lj and 1k tormed in the upper rear part of the case 1. As a result, the slider 2 is permitted to slide in the directions of arrows X - Y while being guided by the guide grooves ij and 1 k. Under the operating arm 2c of the slider 2, there is included the spring 3, one end of which abuts on the protrusion 1d of the case opening 1c and the elasticforce of which urges the slider 2 in the direction of arrow X.The top surface of the spider 2 is formed with the heart-shaped lock groove 2b, in front of which an elongate retraction hole 2 is formed. One end part 4a of the lock pin 4 formed in the shape of letter U is inserted in the lock groove 2b, while the other end part 4b thereof penetrates through the retraction hole 2e of the slider 2 and is turnably inserted in the supporting hole 1e formed in the upper end of the protrusion 1d of the case 1. Further, the upper side of the lock pin 4 is lightly d=9rssed by a keeper plate 12. Both the ends of the keeper plate 12 are inserted and supported in the supporting recesses 1f and 19 which are formed in the case 1.On the other hand, the lower part of the driving member 5 is inserted in a supporting hole 2f formed in the slider 2, and the supporting pins 5a formed on both the sides of the driving member 5 are supported in the supporting recesses 1 h and 1 i formed in the case 1. As a result, the driving member 5 is permitted to turn with the supporting pins 5a as a fulcrum and also so vertically move slightly within the range of the depth of the supporting recesses 1h and li. Further, the spring 11 is inserted in a concave Sc formed in the upper end of the driving member 5, and the lower end 5b of the driving member 5 is held in pressed contact with the upper surface of the rocking plate 8 by the elastic force of the spring 11.The spring 11 is a coiled spring, the upper end 11 a of which is wound into a larger diameter and abuts on the lower surface of the top plate 1a of the case 1. The top plate 1 a is fixed in such a way that pawls 11 and 1 m provided at its lower end are caulked to the case body.

There will now be explained the operations and effects of the switch having the above construction.

The switch operates similarly to the prior-art switch shown in Figure 1. That is, when the operating arm 2a is pushed to move the slider 2 in the Y-direction, the end 4a of the lock pin 4 is shifted to the lock position xofthe lock groove 2b, and the slider 2 is locked in that position. Upon the move ment of the slider 2 in the Y-driection, the driving member 5 turns with the supporting pins 5a as the fulcrum, so that the lower end 5b of the substantially semispherical protuberance of the driving member 5 gets over the supporting point of the supporting terminal 7 on the rocking plate 8 and moves onto the right side of the rocking plate 8.Then, the driving member 5 depresses the right side part of the rocking plate 8 owing to the spring 11, and the rocking plate 8 turns with the fulcrum at its part supported by the supporting terminal 7, so that the contact 8b comes into touch with the contact 1 0a of the stationary terminal 10. Further, when the operat ing arm 2a is pushed again so as to move the slider 2 slightly in the Y-direction, the end 4a of the lock pin 4 is released from the lock position xofthe lock groove 2b. Then the slider 2 is reset in the X-direc tion by the force of the spring 3, and the end 4a of the lock pin 4 is moved to a reset position ywithin the lock groove 2b. At this time, the lower port of the driving member 5 is pushed in the X-direction by the slider 2, so that the driving member 5 turns with the fulcrum at the supporting pins 5a.Eventually, the lower end 5b of the driving member 5 depresses the left end part of the rocking plate 8, and the contact Sa of the rocking plate 8 comes into touch with the contact 9a of the stationarytermina' 9 (the state of Figure 2).

In the above operations, each time the driving member 5 rocks with the supporting pins 5a as the fulcrum, the direction of bending on the spring 11 changes alternately, and the upper end 1 lea of the spring 11 slides abutting on the lower surface of the top plate 1 a. More specifically, in the state of Figure 2, the upper end 1 la of the spring 11 has moved rightward. However, when the slider 2 is moved in the direction of arrow Y, the driving member 5 turns counterclockwise, and therewith, the upper end 11 a of the spring 11 slides and moves Ieftward on the lower surface of the top plate la.Since, at this time, the upper end 1 1a of the spring 11 has the large diameter and abuts on the top plate 1 a in a large area, the pressure on the top plate la is low and the lowersurface of the top plate la is difficult to damage. The upper end 11 a of the spring 11 therefore slides smoothly relative to the top plate 1 a, so that the switching of the slider 2 in the X-Y directions is reliably performed. Moreover, since the spring winding diameter of the upper end part of the driving member 5 is larger than that of the lower part, the rigidity of the spring 11 in the lateral directions is higher than in the prior art. Therefore, the spring 11 becomes difficult of local bending in the rocking operation of the driving member 5, and the lifetime of the spring 11 is enhanced.

As set forth above, according to the present invention, the upper end of a spring for urging a driving member is wound into a larger diameter, and the larger diameter portion is caused to abut on the inner surface of a case, so that the inner surface of the case is difficult to damage. In addition, since the spring does not bend locally, the lifetime of the spring itself lengthens. Further, since the spring is difficult to bend, the switching of a slicer becomes smooth, and the sense of the switching operation of the switch becomes good. Especially in the switch of the type of the present invention, a movable contact is not directly operated by the slider, and hence, the operating sense of the slider becomes light.

Claims (6)

1. li. A push-button switch comprising: (a) a switch case; (b) a supporting terminal which is disposed in a bottom part of said switch case, and a stationary contact which is disposed in the bottom part in a manner to be spaced from said supporting terminal; (c) a rocking plate which has a contact corres pinding to said stationary contact; (d) a slider which slides in said switch case and which is provided with a supporting hole; (e) a coiled spring which has an end part abutting on a top plate of said switch case, said end part having a coil diameter larger than that of the other part; and .' a driving .-m ember in which said coiled spring is arranged and which is normally heid in pressed contact with an upper surface of said rocking plate; (g) said rocking plate being rocked by a movement of said driving member responsive to the sliding of said slider.
2. 2. A push-button switch according to claim 1, wherein said driving member is provided with a concave which receives said coiled spring, and a substantially semispherical protuberance which lies in pressed contact with said rocking plate.
3. 3. A push-button switch according to claim 2, wherein said driving member is provided with a pair of supporting pins, said supporting pins are located in supporting recesses provided in said switch case, and said driving member turns with said supporting pins as a fulcrum.
4. 4. A push-button switch according to claim 1, wherein said slider is heid in a locked state and an unlocked state by a lock pin whose one end is inserted in a locked groove formed in an upper surface of said slider and whose other end is inserted in a supporting hole formed in said switch case.
5. 5. A push-button switch according to claim 1, wherein said rocking plate supported by said supporting terminal has a pair of contacts, and stationary contacts corresponding to said contacts of said rocking plate are disposed in the bottom part of said switch case.
6. 6. A push-button switch substantially as herein described with reference to Figures 2 and 3 of the accompanying drawings.