GB2211996A

GB2211996A - Rotary switch

Info

Publication number: GB2211996A
Application number: GB8725545A
Authority: GB
Inventors: Ying Wai Yu
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-10-30
Filing date: 1987-10-30
Publication date: 1989-07-12
Anticipated expiration: 2007-10-30
Also published as: HK36393A; GB2211996B; GB8725545D0

Abstract

A rotary switch adapted to turn and hold a metal switch blade or contact (24) against a printed circuit board (18) or the like comprises a rotary shaft (12), a knob (14) being provided on a first end of the shaft for turning the shaft about its longitudinal axis, a deformable retaining spring (22) being mounted on the shaft, and a collar (44) having an aperture through which the retaining means can be snap-fitted. Collars of different thickness provide different spring bias. The shaft and collar include matching flats. <IMAGE>

Description

ROTARY OR PIVOT SWITCH This invention relates in general to a rotary or pivot switch and in particular to a rotary or pivot switch having pivot pin with deformable retaining means provided thereon.

Rotary or pivot switches are known in prior art. One common type of pivot switch consists of a pivot pin having a threaded portion provided at the free end thereof and a nut threadably engaged to the threaded portion of the pivot pin to hold a spring on the pivot pin. One of the drawbacks encountered by this kind of pivot switch is that the screwing of the nut onto the pin is a rather time consuming process. Furthermore, the screwing procedure may be incorrectly carried out. Since the nut is used to hold the spring in a suitable compressed state, incorrect placement of the nut with respect to the pin may render a drop in performance of the final product. Also, the pivot pins and nuts are usually fabricated by metal and their production costs are high.

The present invention seeks to provide an improved rotary or pivot switch.

According to the present invention, there is provided a pivot switch adapted to frictionally hold a metal switch contact against a printed circuit.board or the like, the pivot switch comprising a pivot pin having a first and a second end, a switch means being provided on the first end of the pivot pin for selectively turning the pivot pin about the pivot axis, a deformable retaining means being provided on the second end of the pivot pin, a spring means being mounted on the pivot pin, and a collar means having a collar aperture adapted to snap over the retaining means and retained on the pivot pin whereby a switch contact adapted to be rotatable with the pivot pin is frictionally held into position by the spring means which is being compressed by the collar means of an appropriate thickness, said retaining means normally having a retaining dimension exceeding the dimension of the collar aperture, the retaining means being inwardly deformable to a dimension less than the dimension of the collar aperture.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings wherein: Fig. 1 is a side elevation of the pivot switch in accordance with the present invention; Fig. 2 is a perspective view of the pivot pin and the collar as shown in Fig. 1.

Referring now in more detail to the drawing, in which like reference numerals represent like parts throughout the several views, Fig. 1 shows a side view of a pivot switch designated generally by reference numeral 10.

- The pivot switch 10 consists of a pivot pin 12 with a regulating switch member 14 integrally provided thereon at one end thereof. An elongated groove 20 is disposed on the upper surface of the switch member 14 to facilitate rotation of the pivot pin 12 by means of screwdriver or other sharp edged tools. The pivot pin 12 is adapted to journal through an aperture 16 incorporated on a printed circuit board 18. Printed circuit (not shown) are provided on the bottom surface of the printed circuit board 18.

A piece of metal switch blade or switch contact 24 is mounted to pivot pin 12 for rotation therewith. Switch contact 24 is in operative relation to the circuit of the printed circuit board 18 whereby turing the switch contact 24 relative to the printed circuit board 18 at indicated intervals gives rise to various switch connections.

A spring 22 is mounted on the pivot pin 12 and is adapted to urge the switch contact 24 against the printed circuit board 18 under the influence of the spring.

Provided on the other end of the pivot pin 12 is a retaining means generally represented by reference numeral 26. The retaining means 26 is generally in the form of a spear member 28 having a slot 30 extending longitudinally and bisecting the spear member 28. The retaining means 26 can be best illustrated in Fig. 2.

Fig. 2 depicts a perspective view of the pivot pin 12 and the switch member 14 which are moulded in one piece of plastic material. It can be seen that the tip of the spear member 28 is truncated to define a flat surface normal to the axis of the pivot pin 12.

Slot 30 is disposed generally along a longitudinal median line of the pivot pin 12 and extends from the truncated end of the spear member 28 to a substantially central portion of the pivot pin 12. The spear member 28 and the slot portion of the pivot pin 12 together define two elongated members as indicated by reference numerals 36 and 38 in Fig. 2. These two members 36 and 38 are normally in parallel spaced relationship with each other and are deformable inwardly towards each other.

A collar 44 having an aperture 46 is adapted to snap over the spear member 28 and retained in pivot pin 12 by retaining portions 28a and 28b defined by the spear member 28. When collar 44 is pressed against the spear member 28, it exerts a force on the slanted faces of the spear member 28 such that members 36 and 38 are deformed inwardly towards each other allowing the collar 44 to eventually pass through the retaining portions 28a and 28b.

It is appreciated that the retaining portions 28a and 28b normally have a retaining dimension exceeding the dimension of the collar aperture 46. On assembling, the elongated members 36 and 38 are pressed inwardly towards each other and deformed to a dimension less than the dimension of the collar aperture 46.

In the preferred embodiment, the pivot pin 12 is provided bilaterally with two longitudinally extending cutaway portions which define two flat side surfaces 52 and 54 on the pivot pin 12. The cutaway portions extend the entire length of the pivot pin 12 and are in alignment with respective cutaway portions provided on the spear member 28. The collar aperture 46 is conforming in shape to the sectional configuration of the pivot pin 12 so that the collar 44 is capable of mounting to the pivot pin 12 when snaps over the spear member 28.

Conventional pivot switches make use of threaded pivot pins and nuts threadably engaged to the pivot pins to hold spring means on the pivot pins. The disadvantage of this type of pivot switches is that the nuts have to be screwed onto the threaded pivot pins during assembling and that such operation may vary from workers to workers depending on their judgement. Furthermore, the nuts are deemed to be loose retaining means. The pivot switch according to the present invention is a breakthrough to the tradition.

Spring means are fixedly held by collar means which are retained on pivot pin by retaining means. The compressive force of the spring means may vary by selecting collars of different thickness.

Upon assembling the switch contact 24 and the spring 22, the collar 44 is simply snapped over the spear member 28 with resilient deformation of the members 36 and 38.

This permits the pivot switch to be assembled in a very easy manner and thus reduces the amount of labour time required.

Also, due to the simplicity in structure and ease of manufacture, the pivot switch disclosed herein is well suited to mass production and the production cost is relatively low.

Although the retaining means has been described as being in the form of a spear, it is contemplated that the retaining means may take other possible form without departing from the scope of the present invention. For example, the retaining means can take the form of a round head.

While the present invention has been shown and described with particular reference to a preferred embodiment thereof, it should be noted that various other changes or modifications may be made without departing from the scope of the present invention.

Claims

CLAIMS:

1. A rotary or pivot switch adapted to frictionally hold a metal switch contact against a printed circuit board or the like, said pivot switch comprising: a pivot pin having a first end and a second end, a switch means being provided on the first end of said pivot pin for selectively turning said pivot pin about the pivot axis; a deformable retaining means being provided on the second end of said pivot pin, a spring means being mounted on said pivot pin; and a collar means having a collar aperture adapted to snap over said retaining means and retained on-said pivot pin whereby a switch contact adapted to be rotatable with said pivot pin is- frictionally held into position by said spring means which is being compressed by said collar means of an appropriate thickness, said retaining means normally has a retaining dimension exceeding the dimension of said collar aperture, said retaining means being inwardly deformable to a dimension less than the dimension of said collar aperture.

2. A switch as claimed in claim 1, wherein said retaining means takes the form of a spear member having a slot extending longitudinally along a plane parallel to the axis of the pivot pin.

3. A switch as claimed in claim 2, wherein said slot extends to the pivot pin along a portion thereof contiguous with said spear member.

4. A switch as claimed in claim 3, wherein said retaining means and said slot portion of said pivot pin define two elongated members deformable inwardly towards each other.

5. A switch as claimed in claim 2, wherein the peak of said spear member is truncated.

6. A switch as claimed in claim 1, wherein said pivot pin is incorporated with means for rotating said switch contact.

7. A switch as claimed in claim 6, wherein said means is in the form of a cutout portion incorporated on at least a portion of said pivot pin.

8. A switch as claimed in claim 1, wherein said pivot pin is provided bilaterally with two longitudinally extending cutout portions which are in alignment with respective cutout portions incorporated on said retaining means.

9. A switch as claimed in any of the preceding claims, wherein said pivot switch is of a plastic material.

10. A switch substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.