Change-Over Position Display Device for Use in a Switch

The present invention generally relates to a switch in which a movable contact is displaced to at least two positions in a switch casing through a pushing operation or a pulling operation of an operating knob so as to open or close, or change over contacts of the switch. The present invention relates more particularly, to a change-over position display device for use in the switch, in which a plurality of change-over position display portions are provided on the operating knob. A movable light guide for introducing illuminating light from an illuminating light source to any one of the plurality of the change-over position display portions in response to the pushing operation or the pulling operation of the operating knob is provided between the plurality of the change-over position display portions and an illuminating light source such that the any one of the plurality of the change-over position display portions is selectively illuminated by the illuminating light source through the movable light guide in association with any one of positions for opening and closing the switch. The illuminating light source being provided in the switch casing.

Conventionally, in switches in which opening and closing or change-over of contacts thereof is controlled by pulling or pushing the operating knob, it has been a general practice that change-over position display portions are provided on the operating knob. However, the known switches have an inconvenience in that it is difficult to determine which one of the change-over positions is occupied by the switch in the case where the slide switch is provided in a dark location.

Accordingly, an essential object of the present invention is to provide an improved change-over position display device for use in a switch, in which, through a pushing operation or a pulling operation of an operating knob, contacts of the slide switch are opened or closed, or changed over and, at the same time, only one of the change-over display portions corresponding to the pushing operation or the pulling operation of the operating knob is selectively illuminated so as to clearly display the operating state of the switch, with substantial elimination of the disadvantages inherent in conventional change over position display devices of this kind.

Another important object of the present invention is to provide an improved change-over device of the above described type which is simple in structure, highly reliable in actual use, suitable for mass production at low cost, and can be readily incorporated into slide switches and the like at low cost.

In accomplishing these and other objects according to one preferred embodiment of the present invention, there is provided an improved change-over position display device for use in a switch having a switch casing in which a movable contact is displaced to at least two positions through a pushing operation or a pulling operation of an operating knob, said change-over position display device comprising:

a plurality of change-over position display portions which are provided on said operating knob;

an illuminating light source which is provided in said switch casing; and

a movable light guide for introducing illuminating light from said illuminating light source to any one of the plurality of said change-over position display portions in response to the pushing operation or the pulling operation of said operating knob, said light guide is provided between the plurality of said change-over position display portions and said illuminating light source;

whereby any one of the plurality of said change-over position display portions can be selectively illuminated by said illuminating light source through said movable light guide in association with any one of said positions for opening and closing said switch.

In accordance with the present invention, since any one of the plurality of the change-over position display portions is selectively illuminated, it becomes possible to determine which one of the change-over positions is occupied by the switch even at a dark spot.

These and other objects and features of the present invention will become apparent from the following description taken in conjunction with the preferred embodiment thereof with reference to the accompanying drawings, in which;

FIG. 1 is a vertical cross-sectional view of a switch in which a change-over position display device according to one preferred embodiment of the present invention is incorporated,

FIG. 2 is a horizontal cross-sectional view of the switch of FIG. 1,

FIG. 3 is a view as observed in the direction of the arrow III in FIG. 1, and

FIG. 4 is an exploded perspective view showing, on an enlarged scale, a portion of the change-over position display device of FIG. 1.

Before the description of the present invention proceeds, it is to be noted that like parts are designated by like reference numerals throughout several views of the accompanying drawings.

Referring now to the drawings, there is shown in FIGS. 1 and 2, a switch K in which a change-over position display device S according to one preferred embodiment of the present invention is incorporated. The switch K includes an elongated switch casing 1 having a rectangular cross section with an insulator 2 being attached to a lower surface of the switch casing 1. It is to be noted here that all directional indications such as "lower", "front", "rear", etc. relate to the illustration in FIG. 3, hereinbelow.

More specifically, the switch casing 1 includes an upper wall 1a, a rear wall 1b, a right wall 1c, a left wall 1d and the insulator 2 attached to the lower surface of the switch casing 1 and therefor, is formed into an elongated box-like configuration having a front opening 1A of a rectangular shape. Three fixed contacts 3a, 3b and 3c are provided in the insulator 2 and adjacent to the rear wall 1b. The fixed contacts 3a, 3b and 3c are disposed centrally between the right wall 1c and the left wall 1d and in line with each other in a longitudinal direction of the switch K so as to be spaced a predetermined pitch therebetween, respectively with the fixed contact 3c being disposed more adjacent to the rear wall 1b than the fixed contact 3b. A socket 5 for a lamp 4 acting as an illuminating light source is provided in the insulator 2 and forwardly of the fixed contact 3a so as to be disposed in line with the fixed contact 3a and substantially centrally of the switch K in the longitudinal direction thereof. A contact piece 6, which is urged or biased by a spring 7 to project into the switch K, is provided in the insulator 2 and forwardly of the socket 5 so as to be disposed in line with the socket 5 and adjacent to the front opening 1A. Namely, the contact piece 6, socket 5 and fixed contacts 3a, 3b and 3c are provided in the insulator 2 in this sequence in the longitudinal direction of the switch K so as to be disposed in line with each other in the longitudinal direction of the switch K and centrally between the right wall 1c and the left wall 1d with the contact piece 6 being more adjacent to the front opening 1A. Furthermore, engageable grooves 8a, 8b and 8c are formed on an inner face of the upper wall 1a so as to be disposed at positions corresponding to the fixed contacts 3a, 3b and 3c, respectively.

A sliding member 9 is fitted into the front opening 1A so as to be slidable in the longitudinal direction thereof and includes an operating knob 17, a right wall 15a and a left wall 15b. The operating knob 17 is formed at a front end of the sliding member 9 so as to project out of the front opening 1A. A contact holder 10 is integrally formed with or attached to a rear end of the sliding member 9 so as to form a hollow portion 16 enclosed by the operating knob 17, the right wall 15a, the left wall 15b and the contact holder 10, and has a through-hole 11 extending vertically at a central portion thereof. The lamp 4 and the contact piece 6 are provided so as to project into the hollow portion 16 from the insulator 2. A compression spring 13 is fitted into the through-hole 11. Furthermore, an engageable ball 14 and a movable contact 12 adapted to be selectively brought into contact with the fixed contacts 3a, 3b and 3c are provided at an upper portion and a lower portion of the through-hole 11 such that the engageable ball 14 and the movable contact 12 are, respectively, urged vertically in opposite directions remote from each other by the compression spring 13, so that the engageable ball 14 and the movable contact 12 are, respectively, pressed onto the inner face of the upper wall 1a upwardly and an inner face of the insulator 2 downwardly. The engageable ball 14 is selectively brought into engagement with the engageable grooves 8a, 8b and 8c when the slide member 9 is slid in the longitudinal direction of the switch K. This arrangement permits the movable contact 12 to be, respectively, brought into contact with only the fixed contact 3a, with the fixed contacts 3a and 3b, and with the fixed contacts 3b and 3c when the engageable ball 14 is engaged with the engageable grooves 8a, 8b and 8c.

The operating knob 17 has a rectangular recess 17a formed at a front face thereof and a rectangular through-opening 17b. A light transmittable display panel 18 having change-over position display portions 19a, 19b and 19c provided thereon is fitted into the recess 17a so as to be flush with the front face of the operating knob 17. Furthermore, light transmittable lenses 20a, 20b and 20c are fitted into the through-opening 17b so as to be in contact with a rear face of the display panel 18 such that front ends of the lenses 20a, 20b and 20c are, respectively, disposed at positions corresponding to the change-over position display portions 19a, 19b and 19c. The lenses 20a, 20b and 20c are formed with rear ends having an arcuate shape as seen in FIG. 1, which are separated vertically from each other. A light leakage preventive film 21 such as a coating film, a plating film, etc. is formed on outer surfaces of the lenses 20a, 20b and 20c except for their rear end surfaces and front end surfaces.

An elongated movable light guide 22 is pivotally supported by a rod 23 extending horizontally through the right wall 15a and left wall 15b so as to be pivoted about the rod 23 and between the lamp 4 and the change-over position display portions 19a, 19b and 19c. As best shown in FIG. 4, the movable light guide 22 is made of transparent synthetic resin and has a light incoming portion 24 and a light outgoing portion 25 which are, respectively, formed at a rear end and a front end thereof. A light leakage preventive film 26 is formed on an outer surface of the movable light guide 22 except for the light incoming portion 24 and the light outgoing portion 25. It is so arranged that the movable light guide 22 is pivoted such that the light outgoing portion 25 confronts the rear ends of the lenses 20a, 20b and 20c, selectively.

By the above described arrangement of the switch K, when the operating knob 17 is fully pulled out of the front opening 1A such that the engageable ball 14 is brought into engagement with the engageable groove 8a as shown in FIG. 1, the rod 23 is disposed forwardly of the contact piece 6, so that the contact piece 6 is urged by the spring 7 to project into the hollow portion 16 and pushes a rear portion of the movable light guide 22 upwardly and thus, the light outgoing portion 25 confronts the rear end of the light transmittable lens 20a, whereby the change-over position display portion 19a is illuminated.

When the operating knob 17 is pushed into the front opening IA such that the engageable ball 14 is brought into engagement with the engageable groove 8b, the rod 23 is disposed above the contact piece 6 as shown in imaginary lines indicated by A in FIG. 1, so that the movable light guide 22 is held horizontally and thus, the light outgoing portion 25 confronts the rear end of the light transmittable lens 20b, whereby the change-over position display portion 19b is illuminated.

When the operating knob 19 is further pushed into the front opening IA such that the engageable ball 14 is brought into engagement with the engageable groove 8c, the rod 23 is disposed rearwardly of the contact piece 6, so that the contact piece 6 is urged by the spring 7 to project into the hollow portion 16 so as to push a front portion of the movable light guide 22 upwardly and thus, the light outgoing portion 25 confronts the rear end of the light transmittable lens 20c, whereby the change-over position display portion 19c is illuminated.

It should be noted here that the switch K having the change-over position display device S of the present invention incorporated therein illustrates a dimmer switch for changing over a main head lamp "Hi" and an auxiliary head lamp "Lo" for motor vehicles. When the engageable ball 14 is brought into engagement with the engageable groove 8a, the change-over position display portion 19a bearing "OFF" therein is illuminated so as to turn off the main head lamp "Hi" and auxiliary head lamp "Lo". When the engageable ball 14 is brought into engagement with the engageable groove 8b, the change-over position display portion 19b bearing "LOW" thereon is illuminated so as to turn on the auxiliary head lamp "Lo". When the engageable ball 14 is brought into engagement with the engageable groove 8c, the change-over position display portion bearing "HIGH" thereon is illuminated so as to turn on the main head lamp "Hi".

As is clear from the foregoing, in accordance with the present invention, when the contacts are opened or closed or changed over through the pushing operation or the pulling operation of the operating knob, light from the illuminating light source is transmitted to any one of the plurality of the change-over position display portions provided on the operating knob by operating the movable light guide in response to the pushing operation or the pulling operation of the operating knob so as to selectively illuminate any one of the plurality of the change-over position display portions, with the movable light guide being provided between the illuminating light source and the plurality of the change-over position display portions in the switch. Accordingly, in accordance with the present invention, even if the plurality of the change-over position display portions are provided on the operating knob, it is possible to accurately indicate the operating states of the switch even in the case where the switch is provided at a dark spot.

Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be noted here that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as included therein.