US3523167A - Snap switch - Google Patents

Description

Aug. 4, 1970 H. SAUER ETA!- I 3,523,167

SNAP SWITCH Filed Dec. 19, 1967 4 Sheets-Sheet 1 H9 F/g; 2

INVENTORS HANS SAUER YUKIN OBU NISHIDA TAKESHI NISHII 3 4) Arrvs.

Aug. 4, 1970 SAUER ET AL SNAP SWITCH 4 Sheets-Sheet 2 Filed Dec. 19, 1967 l d 4k 6 IA'I'ENTORS HANS SAUER YUKINOBU NISHIDA TAKE5H| NISHII Wo%, MM; VJ LM A 'r TVS,

Aug. 4,- 1970 H. SAUER ETAL 3,523,167

SNAP SWITCH Filed Dec. 19, 1967 4 Sheets-Sheet 3 INVENTORS HANS SAUER Yu| mo5u NISHIDA TAKES'HI NISHII 5 a/ag, W, a ing,

Aug. 4, 1970 H. SAUER ETAL 3,523,167

SNAP SWITCH Filed Dec. 19, 1967 4 Sheets-Sheet 4 l/\-' VE N TO R5 HANS SAUER YUKINOBU NISHIDA TAKESHI, NISHH TYS,

United States Patent "ice 3,523,167 SNAP SWITCH Hans Sauer, Munich, Germany, and Yukinobu Nishida, Kadoma, and Takeshi Nishii, Osaka, Japan; said Nishida and said Nishii assignors to Matsushita Electric Works, Ltd., Osaka, Japan, a corporation of Japan Filed Dec. 19, 1967, Ser. No. 691,742 Claims priority, application Japan, Dec. 24, 1966, 41/ 84,683; May 29, 1967, 42/34,441 Int. Cl. HOlh 13/36 U.S. Cl. 200-67 6 Claims ABSTRACT OF THE DISCLOSURE The structure of snap switch, wherein the edge of a fine width part of a contact arm provided with a contact is engaged with a notch in an operating member having a bent part, a cut groove made in a lower end extension of the bent part of said operating member is engaged with a bearing part of an L-shaped member and a spring is resiliently set between said contact arm and the notch made in the L-shaped member. By the above structure, when a pushbutton mounted on a fiat part on the upper surface of the operating member is pressed or released, the contact of the contact arm will come into contact with a lower fixed contact or upper fixed contact connected integrally with a terminal to open or close the switch.

This invention relates to improvements in snap switches.

Generally, a snap switch is required to have operation characteristics on a fixed level in the use, irrespective of its size. The movement until an operation and the movement after the operation of such snap switch have the greatest influence on its mechanical life. The movement until the operation is 0.5 mm. at the maximum and the movement after the operation is about 0.1 to 0.15 mm. Therefore, the smaller the switch, the shorter the span and the larger the deflection of the spring and, as a result, the shorter the life of the switch will be. Further, in order to reduce the force required for the operation and to improve the snapping characteristics, it is necessary to reduce the thickness of the spring plate. If it is carried out, the current density will become so high that the capacity will not be able to be made large. In the present invention, the above mentioned problem has been solved by making the contact spring and operating spring independent of each other, increasing the thickness of the contact spring and chamfering the insides of the operating member and operating spring engaging part.

The adjustment of the pushbutton stroke has been so far little carried out. Even if the component parts are small and the precision is raised, if the accumulation of tolerances is considered, it will be found that the accumulated value of the tolerances will occupy some percentage of the movement of the entire switch. Further, the fiunctuation of the pushbutton stroke will be so large as to influence the life. In the present invention, in fixing the supporting member, the calked part of the common embedded terminal is plastically deformed on both sides only, the supporting member is calked and the height of the remaining middle part is pressed as required so that the entire movement by the fluctuation of the component parts may be adjusted.

The respectively separate N and N contacts and terminals have been conventionally fixed by calking or welding. Therefore, the more the joints, the higher the contact resistance and the more the unstable elements. In the present invention, the above mentioned problem has been solved by making the contact part and terminal part integral with each other so that the joints may be less and the contact resistance may be stabilized.

3,523,167 Patented Aug. 4, 1970 If the voltage-proofness test, contact resistance test and operation characteristic test can be carried out before fitting the cap in the respective processes of assembling switches, less fouls will be found in the final process and the loss in the production will be able to be reduced. In the present invention, it is attempted to solve the above mentioned problem by bringing the supporting member into contact with the back surface of the operating member so that the same fulcrum relation as fitting the cap may be kept in the state before fitting the cap.

A main object of the present invention is to provide a snap switch of a very small size, large capacity and long life.

Another object of the present invention is to provide a switch assembled of component parts so small that the assembly and engagement with each other are simple and positive.

FIG. 1 is a sectioned view of a switch according to the present invention in a free state with the pushbutton released.

FIG. 2 is a plan view showing the switch mechanism part with the cap removed.

FIG. 3 is a sectioned view of the switch with the pushbutton pressed.

FIG. 4 is a perspective view showing the mechanism of the switch as disassembled.

FIG. 5 is a view for explaining the operation of the switch.

FIGS. 6 to 9 show the second embodiment and correspond respectively to FIGS. 1 to 4.

FIG. 10 shows an L-shaped member as secured to the terminal.

FIG. 11 is a sectioned view of a contact member on line XX in FIGS. 4 and 9.

Now the present invention shall be explained with reference to FIGS. 1 to 4. In the drawings, 1 is a base for setting the mechanism of a switch. A circular through hole 12 and elliptic through hole 13 for fitting the switch to a panel are made in the base 1. Further, terminals 4, 5 and 6 for the connection with outside conductors are embedded and molded integrally with the base 1. In order to form a switch, said terminals 4, 5 and 6 are integrally provided, respectively, with a columnar rivet part 16 to have an L-shaped member 7 calked, with an upper fixed contact 17 and with a lower fixed contact 18 of the switch. Said rivet part 16 of the terminal 4 is to be inserted into a hole 23 in the L-shaped metal member 7 and to be calked on both sides so as to form a projecting part 16 in the middle. This projecting part 16 is made to be a stopper for adjusting the push button stroke (see FIG. 10). Further, each of the terminals 4, 5 and 6 has a smaller diameter part 32 and knurled parts 14 and 15 so that it may not drop off the base 1 or may not rotate after it is embedded and molded integrally with the base 1. The upper fixed contact 17 and lower fixed contact 18 provided respectively on the terminals 5 and 6 are to be bent and molded with proper jigs after the terminals are embedded and molded.

2 is a cap of the switch. A pushbutton hole 33 for fitting a pushbutton 3 is made in said cap 2. After the switch mechanism is mounted on the base 1, said cap 2 is bonded to the base 1 with a proper adhesive, while the pushbutton 3 is fitted in the cap 2. Said pushbutton 3 is to be in contact with the bent part 30 of an operating metal member 8.

7 is an L-shaped metal member to be used as a part of the switch mechanism. The through hole 23, through which the rivet part 16 extending integrally with the terminal 4 is to be inserted, is made in the L-shaped member 7. A bearing part 22 and an arm 21 substantially at right angles with the bearing part 22 are provided on the member 7. Said arm 21 is provided with a notch 21' and has projections 21" projecting on both sides. Further, a projection 24 to fit in a small hole 34 made in the base 1 is provided to project on the lower surface of the L-shaped member 7.

8 is a substantially Z-shaped operating metal member of the switch mechanism. A cut groove 29 to engage with the bearing part 22 of said L-shaped member 7 is made in a lower end extension 40 bent downward substantially at right angles to the flat part 39 on the upper surface of the Z-shaped member 8. Said cut groove 29 has at both sides projections 31 for preventing the sidewise swing of the operating member 8 while the groove is engaged with the above mentioned bearing part 22. The contact part of said out groove 29 with the bearing part 22 is finished to be knife-edge 35. Further, a notch 28 to engage with the fine width part 25 of a contact arm 10 is made in an upper end extension 28 bent upward substantially at right angles to the above mentioned flat part 39 on the upper surface. The pushbutton 3 is to be in contact with the bent part 30 of the upper surface flat part 39.

9 is a curved spring for giving a snapping force to the switching mechanism and has engaging projections 19 and 20 at its respective ends. Said projection 19 is to be engaged with the notch 21' of the above-mentioned L-shaped member 7, and said projection 20 is to be engaged with the lower surface of a projection 26 of the contact arm 10.

Further, the contact arm 10 has the peripheral edge enclosed with the fine width part 25 so as to have a through hole 27 having a space sufficient not to interfere with the snapping motion of the spring 9 and has a contact 11 calked at one end. Said fine width part 25 to engage with the notch 28 of the operating member 8 is inwardly chamfered and the projection 26 formed at an end of the through hole 27 to engage with the spring 9 is also inwardly chamfered so that it may be possible to use a thicker plate for the contact arm so as to enable to increase the current capacity of the switch and, at the same time, to effect smooth snapping operations. 36 is a notch provided at the respective sides of said projection 26. (See FIG. 11.)

As detailed above, in the snap switch of the present invention, the spring 9 is formed of a separate part and is set between the lower surface of the projection 26 located on the contact side of the contact arm 10 and the notch 21' of the L-shaped member 7, further one end of the fine width part 25 opposed to the projection 26 of the contact arm 10 is set as stretched into the notch 28 of the operating member 8, the cut groove 29 in the lower end extension 40 of said operating member 8 is engaged with the bearing part 22 of the above mentioned L-shaped member 7 and the pushbutton 3 is mounted in contact with the above mentioned bent part 30 so that the above mentioned contact arm 10 may become a tension member and the spring 9 may become a compression member to form a dead center mechanism and that, when the pushbutton 3 is pushed or released, the above mentioned operating member 8 may make an arcuate motion with the knife-edge 35 of the cut groove 29 as a fulcrum and the switch mechanism may be operated.

That is to say, while the pushbutton 3 is not pressed, the contact 11 of the contact arm 10 will be kept in contact with an upper fixed contact 17 but, when the pushbutton 3 is now pressed, the operating member 8 will gradually make an arcuate motion downward with the knife-edge 35 as a fulcrum. This state is represented by Ob a c in When the pushbutton 3 is further pressed, due to the dead center mechanism formed of the contact arm 10 and spring 9, the contact arm 10 will quickly snap downward. Therefore, the contact 11 kept in contact with the above mentioned upper fixed contact 17 will quickly snap downward into Contact with the lower fixed contact 18. To explain this state in FIG. 5, the first dead center operating position O b a c will be taken from the free position O b a c. In this snapping, the contact 11 of the contact arm 10 will move for the breaking distance a a between the contacts, will therefore snap and will at the same time return to the line a db that is [1 -917 with the intersection of the center line x of the pushbutton 3 and the axis a -b of the first dead center operating position as a center but the position d of the pushbutton 3 will not vary but will remain in the first dead center operating position.

When the pushbutton 3 is then released, the contact arm 10 will be moved upward by the accumulated energy of the spring 9. At this time, the contact arm 10 forming the dead center mechanism will quickly move upward and therefore the contact 11 will be also quickly switched into contact with the original upper fixed contact 17 and will thus return to the original free state.

This state means to return to the free position O- b +a c from the snapping instantaneous releasing position Oeb., a c through the second dead center releasing position O b a ec in FIG. 5.

The line O+b a c show in FIG. 5 is of the state in which a further stroke is given over the first dead center operating position. It represents a state in which all the stroke mechanically allowable as for a snap switch is given to stop the contact.

In the above explanation of the operation, the operation characteristics of the switch represented by the push button 3 can be easily obtained by determining the distances between the intersections with the center line x of the pushbutton 3 by the movement until the opera tion or the pre-travel at an angle of b -O-b the movement after the operation or the over-travel at an angle of b O-b and the difference of the movement or the differential movement at an angle of b Ob The advantages of the snap switch of the present invention are that, as the spring 9 is made independent, a comparatively thick material can be used for the material of the contact arm 10, the switch can be made small in the size and large in the capacity, the contact arm 10 will be subjected only to a tension by the resilient spring 9 without being mechanically distorted and, as the secondary moment of the cross-section is proportional to the third power of the plate thickness, the mechanical life of the contact arm can be prolonged.

What is to be further noted is that the moving distance of the contact arm 10 engaged with the notch 28 of the operating member 8 will be enlarged to be so large in said engaging part that, at the moment when the contact 11 comes into contact with either of the upper and lower fixed contacts 17 and 18 in proportion to this relative movement, said contact 11 will be in sliding contact with the contact surface and will always keep it clean.

Further, there are also advantages that the operating member 8 and the L-shaped member 7 are engaged with each other by the engagement of the bearing part 22 with the cut groove 29, and the operating member 8 and the contact arm 10 are engaged with each other by the engagement of the fine width part 25 with the notch 28 so as to be respectively simply assembled.

FIGS. 6 to 9 show another embodiment. According to this embodiment, a ball 37 is interposed between the bottom surface of the pushbutton 3 and the flat part 39 on the upper surface of the operating member 8 so that the function of the switch may be further improved.

The differences of this embodiment from the preceding embodiment shall be specifically explained. In FIGS. 6 to 9, a recess 38 for rotatably fitting and inserting a steel ball 37 is formed in the flat part 39 on the upper surface of the operating member 8 and the steel ball 37 is set in contact with the bottom surface of the push button 3. Said steel ball is substantially spherical, is to be low in the friction coefiicient and is thus made any of chromium steel, stainless steel, brass or synthetic resin. It is most preferable to make the recess 38 to be of a radius a little larger than that of the above steel ball 37.

In the snap switch of the present invention, as the steel ball 37 is interposed between the above mentioned pushbutton 3 and operating member 8 and is positioned rotatably in the recess 38 formed in the flat part 39 on the upper surface of the operating member 8 as in the above, the friction between the pushbutton 3 and the operating member 8 will be small, the force required for the operation can be made small, the resiliency of the spring 9 under the same load for the required performance can be increased and therefore a suflicient contact pressure at the contact point can be obtained. Further, the steel ball rotates so smoothly that the precision of the repetition of the operation of the switch will improve. Therefore, there can be obtained a snap switch which can be adapted to highly frequently repeated operations and is small in the size, large in the capacity, long in the life and excellent in the operation characteristics.

What is claimed is:

1. An electrical snap switch comprising the combination of a pair of spaced stationary contacts, a movable contact arm having a contact mounted on one end thereof and disposed between said stationary contacts, the other end of said arm extending laterally away from said contatcs and having an opening formed therein, a terminal member spaced away from said contacts in the same direction as said other end of said arm and on a first side of said arm, a mounting member connected to said terminal member and including an arm portion aligned with said opening in said contact arm, an operating member connected at one end to said other end of said contact arm and pivotally connected at the other end to said mounting member between said terminal and said contacts and on said first side of said contact arm, an intermediate portion of said operating member extending from said first side of said contact arm through said opening to the other side of said contact arm, spring means disposed within said opening formed by said contact arm and biasing said contact arm and said operating member away from said terminal member and said arm portion of said mounting member to engage the contact on said contact arm with one of said stationary contacts, and a pushbutton engaging said intermediate portion of said operating member on said other side of said contact arm for pivoting said operating member and, said arm against the bias of said spring means to engage the contact on said contact arm with the other one of said stationary contacts.

2. An electrical snap switch as set forth in claim 1 wherein a ball of hard material is interposed between a recess formed in the upper surface of said operating member and said pushbutton.

3. An electrical snap switch as set forth in claim 1 wherein the end of said operating member engaging said contact arm forms a notch for receiving an edge of the opening in said contact arm, the upper and lower engaging surfaces of said contact arm and said notch being chamfered.

4. An electrical snap switch as set forth in claim 2 wherein the end of said operating member engaging said contact arm forms a notch for receiving an edge of the opening in said contact arm, the upper and lower engaging surfaces of said contact arm and said notch being chamfered.

An electrical snap switch as set forth in claim 1 wherein said mounting member is riveted to the end of said terminal member, said riveted part being positioned so as to engage said operating member on said first side of said contact arm when said operating member is pivoted by depression of said pushbutton, and said riveted part being transformable to provide means for adjusting the stroke of said pushbutton.

6. An electrical snap switch as set forth in claim 2 wherein said mounting member is riveted to the end of said terminal member, said riveted part being positioned so as to engage said operating member on said first side of said contact arm when said operating member is pivoted by depression of said pushbutton, and said riveted part being transformable to provide means for adjusting the stroke of said pushbutton.

References Cited UNITED STATES PATENTS 2,935,580 5/1960 Jaidinger. 3,178,528 4/1965 Panicci et a1. 3,291,930 12/ 1966 Hipple.

FOREIGN PATENTS 836,156 6/ 1960 Great Britain. 933,765 7/ 1963 Great Britain.

ROBERT K. SCHAEFER, Primary Examiner D. SMITH, 111., Assistant Examiner

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