GB1559926A - Electrical switch casing and base plate construction - Google Patents

Description

(54) IMPROVED ELECTRICAL SWITCH CASING AND BASE PLATE CONSTRUCTION (71) We, ALPS ELECTRICAL COMPANY LIMITED, a Corporation organised under the laws of Japan, of 1-7 Yukigaya, Otsukacho, Ota-ku, Tokyo, Japan, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to an improved construction for attaching a base plate to a switch casing of an electrical switch.

According to the invention there is provided an electrical switch comprising a generally rectangular switch casing having an open top portion and an open bottom portion, and a base plate having a plurality of terminals and adapted to be attached to said switch casing near its open bottom portion, said switch casing having a stepped portion formed by a flange element extending inwardly from the side wall of said switch casing at a location near said open bottom portion, and a plurality of elongate tongue portions each inclined inwardly from said top portion of said switch casing to a location spaced just above said stepped portion, whereby said base plate can be attached to said switch casing by inserting it down through said open top portion to deflect said tongue portions outwardly until the base plate engages upon said stepped portion whereupon said tongue portions will return to their initial position and engage the upper surface of said base plate to hold it between said tongue portions and said stepped portion.

The invention will become further apparent from the following description given by way of example with reference to the accompanying drawings, in which: FIGURE 1 is a perspective view of a conventional prior art combination of a switch casing 11 and a base plate 12; FIGURE 2 is an exploded perspective view of a construction in accordance with the invention: and FIGURES 3A, 3B, 3C and 3D are sec tonal views of the stages in attaching the base plate to the switch casing of the construction illustrated in Figure 2.

A typical prior art conventional construction for attaching a base plate to a switch casing is shown in Figure 1 and employs a frame 11 formed of a metallic plate having a plurality of legs or tabs 1 it. These tabs are plastically deformed to secure the base plate 12 to the frame and thereafter the base plate 12 is often fixed to the frame by suitable means such as caulking, Referring to Figures 2 and 3A-D showing an embodiment of the present invention, a switch casing 1 in the form of a rectangular open ended frame is made of a plastics material, and is provided -with a flanged section la and an arm portion-- 1b by means of which the switch casing can be attached to an attaching plate (not shown).

The frame or switch casing is further provided at its inner surface and close to one open end lc (located at the bottom in the drawings) with a stepped portion ld, and inwardly inclined elongate tongue portions le extending toward the stepped portion ld.

The stepped portion 1d may extend all round the inner periphery of the one open end lc or may comprise a plurality of separate stepped portions. In the embodiment illustrated a stepped portion 1d is provided inside each closed end wall of the frame with the tongue portions le being provided inside each of the two remaining side walls.

A base plate 2 is typically constituted by a laminated plate made from a phenolic resin, and is provided with a plurality of fixed terminals 3. An actuator lever 5 made of a plastics material has bores or slots for receiving movable contacts 9 and another bore for receiving a coiled spring 7. The actuator 5 is rotatably mounted on the frame by means of a shaft 6.

The attachment of the base plate to the switch casing is made in the following manner.

At first, the base plate 2 is inserted into the frame through another open end if (shown in the drawings as at the top) of the latter, i.e., where the stepped portions id are not provided. Consequently, the ends 2a and 2b of the base plate come into contact with the inwardly and downwardly sloping tongue portions le of the switch casing. As the base plate 2 is further depressed deep into the frame 1, the tongue portions le are each resiliently deformed outwardly as shown in Figure 3B.

When the base plate 2 has been depressed far enough so as to come into contact with the stepped portions id at either side of the frame the ends 2a and 2b of the base plate 2 disengage from each of the tongue portions le which flex back to the condition as shown in Figure 3C in which the base plate 2 is held between the stepped portions 1d and the tongue portions le.

The actuator 5 is then loaded with a coiled spring 7 and a ball 8, while movable contacts 9 are arranged on the fixed terminals 3. Finally, the actuator 5 is rotatably secured to the switch casing 1 by the supporting shaft or pin 6 to complete the assembling to the condition shown in Figure 3D.

In operation, the actuation 5 is operated by pivoting about the pin 6 to cause a displacement of the movable contacts 9 to effect switching between desired fixed contacts.

The illustrated construction comprising a stepped portion at one open end of a switch casing and tongue portions extending from the inner surfaces of the switch casing toward the stepped portion for holding the base plate, is simple and easy to assemble, and ensures a safe attaching of the base plate to the switch casing.

WHAT WE CLAIM IS:- 1. An electrical switch comprising a generally rectangular switch casing having an open top portion and an open bottom portion, and a base plate having a plurality of terminals and adapted to be attached to said switch casing near its open bottom portion, said switch casing having a stepped portion formed by a flange element extending inwardly from the side wall of said switch casing at a location near said open bottom portion, and a plurality of elongate tongue portions each inclined inwardly from said top portion of said switch casing to a location spaced just above said stepped portion, whereby said base plate can be attached to said switch casing by inserting it down through said open top portion to deflect said tongue portions outwardly until the base plate engages upon said stepped portion whereupon said tongue portions will return to their initial position and engage the upper surface of said base plate to hold it between said tongue portions and said stepped portion.

2. A switch according to claim 1, wherein said casing is made from a plastics material.

3. An electrical switch constructed and arranged substantially as herein described with reference to and as illustrated in Figures 2 and 3 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. the frame through another open end if (shown in the drawings as at the top) of the latter, i.e., where the stepped portions id are not provided. Consequently, the ends 2a and 2b of the base plate come into contact with the inwardly and downwardly sloping tongue portions le of the switch casing. As the base plate 2 is further depressed deep into the frame 1, the tongue portions le are each resiliently deformed outwardly as shown in Figure 3B. When the base plate 2 has been depressed far enough so as to come into contact with the stepped portions id at either side of the frame the ends 2a and 2b of the base plate 2 disengage from each of the tongue portions le which flex back to the condition as shown in Figure 3C in which the base plate 2 is held between the stepped portions 1d and the tongue portions le. The actuator 5 is then loaded with a coiled spring 7 and a ball 8, while movable contacts 9 are arranged on the fixed terminals 3. Finally, the actuator 5 is rotatably secured to the switch casing 1 by the supporting shaft or pin 6 to complete the assembling to the condition shown in Figure 3D. In operation, the actuation 5 is operated by pivoting about the pin 6 to cause a displacement of the movable contacts 9 to effect switching between desired fixed contacts. The illustrated construction comprising a stepped portion at one open end of a switch casing and tongue portions extending from the inner surfaces of the switch casing toward the stepped portion for holding the base plate, is simple and easy to assemble, and ensures a safe attaching of the base plate to the switch casing. WHAT WE CLAIM IS:-

1. An electrical switch comprising a generally rectangular switch casing having an open top portion and an open bottom portion, and a base plate having a plurality of terminals and adapted to be attached to said switch casing near its open bottom portion, said switch casing having a stepped portion formed by a flange element extending inwardly from the side wall of said switch casing at a location near said open bottom portion, and a plurality of elongate tongue portions each inclined inwardly from said top portion of said switch casing to a location spaced just above said stepped portion, whereby said base plate can be attached to said switch casing by inserting it down through said open top portion to deflect said tongue portions outwardly until the base plate engages upon said stepped portion whereupon said tongue portions will return to their initial position and engage the upper surface of said base plate to hold it between said tongue portions and said stepped portion.

2. A switch according to claim 1, wherein said casing is made from a plastics material.

3. An electrical switch constructed and arranged substantially as herein described with reference to and as illustrated in Figures 2 and 3 of the accompanying drawings.