GB2128028A - Electric switches - Google Patents

Abstract

A rocker switch has a spring (26) biased movable contact (18) which is continually connected to an electrical potential source (14) and a lamp (30) in an actuator (20) has one lead (32) connected to this spring and the other (30) to a uniquely located resistor (22) such that the resistor (22) is connected in one switch position to an upper part (12a) of one fixed switch contact (12) for illuminating the lamp (30). The lamp wires (32,34) and the resistor (22) are retained in the actuator (20) by means which permits ease of assembly. <IMAGE>

Description

SPECIFICATION Electric switches The invention relates generally to electric switches and especially but not exculsivelyto switches of the type shown in issued U.S. patent No.4,317,417.

Illuminated electrical switches generally include a lamp mounted in the actuator itself. The U.S. Patent No. 4,347,417 shows an illuminated rocker/actuator with a lamp mounted in the rocker and with a resistor circuit associated with the lamp.

The invention provides an electric switch including a casing with interior fixed contacts, an actuator supported by the casing for movement between first and second limit positions, a movable contact on the actuator which is urged towards the fixed contact by lost motion means, in which the actuator mounts a lamp in a resistor circuit, one end of which is electrically connected to the movable contact through the lost-motion means and the other end of which abuts an elevated part of one of the fixed contacts in the first limit position only.

The invention preferably uses a rocker for the actuating means and more especially a rocker with a recess for retention of the resistor in the rocker. The recess can be designed for facilitating the assembly of the rocker with its resistor and the lamp. Another possible benefit is in the convenient retention of the lamp leads associated with the resistor and lamp.

In providing an electric switch with a selectively illuminated rocker, the preferred form for the switch casing or case has three fixed contacts in a bottom wall thereof, one of which contacts is always connected to the movable contact (preferably the centre contact) and the other two of which fixed contacts are selectively placed in electrical series circuit with the movable contact as a result of pivotal movement of the rocker. The resistor is preferably arranged in the rocker, and one of these other two fixed contacts is so shaped that in one position of the rocker a resistor circuit is closed by engagement between the resistor itself and said one of said other two fixed contacts. The rocker may have a depending central portion or post cooperable with and adapted to shift the movable contact as a result of rocker movement.The resistor can be retained in an inwardly open rocker recess adjacent one end of the rocker, and the lamp may be located in a recess adjacent the opposite end of the rocker.

In accordance with the invention this resistor recess may have opposed generally cylindrical surfaces with their respective axes oriented at an acute angle to one another so that one of them guides the generally cylindrical recess into place during insertion at assembly, and so that the other of said cylindrical surfaces has a portion so spaced from the one surface that after having been so inserted the resistor can be pivoted about its innermost end in the actuator until its outer end has moved past lips on the said other cylindrical surface so as to hold the resistor securely in place.

The lamp may have two lead wires, one being connected to a coil spring on an inwardly projecting actuator portion so as to be connected in electrical series circuit with both the spring and the movable contact; the other lamp lead wire being connected to an inner end of the resistor. Both lamp lead wires may be located on assembly in V-shaped slots in webs or walls of the actuator which walls are integrally formed and serve to provide the recess for the resistor and central annular recess surrounding the depending post for receiving the spring.

Drawings Figure 1 shows a vertical section through a switch according to the invention; Figure 2 is a framentary, part exploded vertical section through a portion of the rocker mounting the resistor, spring and lamp of the switch of Figure 1; Figure 3 is a bottom view of the actuator depicted in Figure 2 with the lamp lead wires in assembled position prior to assembly of the resistor and coil spring; and Figure 4 is a vertical section taken generally on the line 4-4 of Figure 1.

Figures 1 to 4 shows a preferred form of an electrical rocker switch of the type having an illuminated rocker. The switch is well adapted to low cost, high quantity mass production for reasons to be described.

The switch includes a moulded plastics base 10 having an upwardly open cavity 10a defined in part by a bottom wall lob. Three'fixed contacts 12, 14 and 16 are provided in the bottom wall 1 0b of the plastics case 10. One of these contacts 14 is located centrally of the generally rectangular switch base with the other two contacts 12 and 16 being spaced therefrom and having portions adapted to be engaged by opposite ends of a movable contact 18.

The movable contact 18 may be identical to that shown and described in US Patent No.4,347,417. It is a feature of the invention that this movable contact 18 is adpated to be moved as a result of pivotal movement of a rocker 20 from the position shown in full lines in Figure 1 to that in broken lines.

With reference to the U.S. Patent No.4,347,417, it is a feature of this type of electrical switch that a coil spring 26 is provided on a depending central post portion 20c of theactuator in order that the lower end of this spring 26 may engage, continually, the movable contact 18 and so is maintained at an electrical potential equivalent to that of the movable contact 18. Thus, in the position shown in Figure 1 and with a load voltage applied to contact 14, a circuit is created as long as contact 16 is connected to ground or neutral. So too, with the contact 18 in the broken line position shown in Figure 1 and the same load applied to the central contact 14 a circuit is created through contact 12, which may be ground or neutral.

In accordance with the invention means is provided for selectively opening and closing a resistor circuit defined in large part by elements located in the actuator 20, and more particularly by a resistor 22, lamp 30, and associated lamp lead wires 32 and 34. As shown in Figure 1 lead wire 32 from lamp 30 is electrical!y connected to the upper end of spring 26 and lamp lead wire 34 is electrically connected to the upper resistor 22. Thus, when the actuator 20 is in the solid line position shown in Figure 1 the lower end of resistor 22 contacts the upper end 12a of fixed contact 12 causing the lamp to light. The lamp is off in the broken line position.

Turning next to a detailed description of the specific configuration of the actuator 20 and particularly the retention means for retaining the lead wires for the lamp, Figure 2 shows the actuator with its central depending post 20c adapted to slidably receive the spring (not shown in this view).

The lamp 30 (also not shown in this view) is adapted to be slidably received in recess 20a. It is a feature of the present invention that one of the lamp lead wires 34 has a portion adapted to be received in a slot 20b defined in a depending web or wall defined integrally with the rocker/actuator 20. As also shown in Figure 3 the V-shaped slot 20b receives lead wire 34, which lead wire has an end portion adapted to be received in similarly shaped slots 20d, 20d being defined for this purpose in the depending web walls of the resistor recess. The other lamp lead wire 32 also passes through a V-shaped slot 20e (Figure 3) in the lamp recess sidewall and extends through the annular recess 20f so as to contact the upper end of the spring (not shown in Figure 3).This lamp lead wire 32 has an end portion extending through a slot 209 in this annular recess sidewall 20f as shown in Figure 3. As so constructed and arranged the resistor circuit provided in the actuator 20 will always include the spring, the lamp leads 32 and 34, the lamp 30 (not shown) and the resistor 22 so that a circuit is closed when the lower end of resistor 22 contacts the upper end 12a of fixed contact 12 as described previously.

Turning next to a more detailed description of the manner in which the resistor 22 is assembled with the actuator 20, and more particularly with the resistor recess, Figure 2 shows the resistor initially inserted inthe direction of arrow 24. The resistor 22 is generally cylindrical in configuration and moves parallel to a generally cylindrical surface 20b (see Figure 3) defined in a depending web or wall of the actuator 20 for this purpose. Once the inner end 22a of resistor 22 contacts the wire 34 the resistor 22 is pivoted in the direction of arrow 26 until the lower end portion of the resistor 22 moves past lips 20j, 20j in order to releasably retain the resistor 22 in the broken line position shown in Figures 2 and 3.These lips 20j and 20j also serve to guide the resistor 22 during vertical insertion in the direction of the arrow 24 in Figure 2 and provide retention means for the resistor so that it can be conveniently assembled with the acutator 20 and so that it is securely held in the actuator following assembly in accordance with the preceding procedure.

As so constructed and arranged the actuator is well adapted to being assembled with its lamp and resistor in an automated production line. The V-shaped slot defined between the angled surfaces 20h and 20k will accommodate a tool (not shown) such that resistor 22 can be pivoted into position as described above. Assembled in this way, the resistor retains the lamp lead wire 34 in place. The lamp 30 is also well adapted to assembly as described above, the lead wires being efficiently guided into place by the V-shaped slots 20b, 20e, 20g, and 20d, 20d.

Because contact between the lamp-resistor circuit and elevated part of the fixed contact is only desired in the first limit position, the use of a resilient or extensible electrical connection, such as a coil spring, to maintain electrical contact between the casing and the actuator, in addition to that provided by the lost motion means, becomes unnecessary and is omitted.

Claims (24)

1. An electric switch including a casing with interiorfixed contacts, an actuator supported by the casing for movement between first and second limit positions, a movable contact on the actuator which is urged toward the fixed contact by lost motion means, in which the actuator mounts a lamp in a resistor circuit, one end of which is electrically connected to the movable contact through the lost-motion means and the other end of which abuts an elevated part of one of the fixed contacts in the first limit position only.

2. A switch according to claim 1 in which the elevated part has an upper transverse part for engaging the lamp-resistor circuit in the first limit position and a lower transverse part for engaging the movable contact in the second position.

3. A switch according to claim 1 or claim 2 in which the resistor is mounted in the actuator so that one end thereof abuts the elevated fixed contact part in the first limit position.

4. A switch according to claim 3 in which the actuator includes a lead for interconnecting resistor and the lamp and the lead is arranged to contact the other end of the resistor.

5. A switch according to any of the preceding claims in which a lead is mounted in the actuator connected at one end to the lamp and the lost motion means is a spring retained by an interior projecting part of the actuator and electrically connected to the other end of the lead.

6. A switch according to any of the preceding claims in which the actuator is pivotably supported on the casing for movement between the first and second limit positions.

7. A switch according to any of the preceding claims in which the actuator has recesses for mounting the lamp and resistor on either side of the lost motion means and the resistor recess defines a pair of channels oriented at an acute angle with respect to each other, one channel being adapted to guide the resistor into the actuator, the other channel being adapted to retain and locate the resistor in clamping engagement by moving the resistor transversely from one to the other channel.

8. A switch according to claim 7 in which the actuator includes a rocker of light transmitting plastics material, the resistor and lamp recesses being formed within the rocker by integral inwardly projecting webs, said webs having convergent slots for receiving and locating leads for completing the lamp-resistor circuit.

9. An electrical switch substantially as described with reference to and as shown in the Figures.

10. An electric switch comprising a case having a cavity with sides and a bottom wall, fixed switch contacts provided in said bottom wall, said case defining actuator support regions, an actuator supported by said case regions for movement between first and second limit positions, a lamp provided in said actuator, a resistor circuit associated with said lamp, a movable contact slidably received inside said cavity for movement across the upper ends of certain of said fixed contacts in response to said actuator movement, electrically conductive lost motion means between said actuator and said movable contact to urge the latter toward the upper ends of certain fixed contacts, at least one fixed contact having its upper end spaced above said upper ends of said certain fixed contacts and defining a conductive abutment for engaging a portion of said resistor circuit in said actuator only when the latter is in said first limit position.

11. The switch according to claim 10 wherein said upper end of said one fixed contact has a C-shaped offset portion with the upper leg of the C-shape defining said conductive abutment.

12. The switch according to claim 10 wherein said resitorcircuit includes a resistor, one end of said resistor defining said portion of said circuit for engaging said conductive abutment.

13. The switch according to claim 11 wherein said resistor circuit includes a resistor provided in said actuator and a conductive lead connecting said resistor to said lamp, one end of said resistor to said lamp, one end of said resistor which is opposite said end connected to said lamp by said lead, which said one resistor end defines said portion of said resistor circuit for engagement with said conductive abutment when said actuator is in its first limit position.

14. The switch according to claim 13 wherein said conductive lost motion means comprises a metal spring in contact with said movable contact, a depending portion of said actuatorfor retaining said spring, and a second conductive lead connecting said lamp to an upper end of said spring whereby said first actuator limit portion causes said movable contact to bridge said certain fixed contacts and to provide a closed circuit for said lamp and resistor through said one fixed contact as a result of engagement between the upper end thereof and said one end of said resistor.

15. The switch according to claim 14wherein said one fixed contact also includes a tab portion spaced below the upper end and defined above said lower leg of said C-shaped offset portion, said tab adapted to support said movable contact element in said second position of said actuator.

16. The switch according to claim 10 wherein said actuator support regions comprise openings in said case side walls, and wherein said actuator has projecting portions pivotally supporting said actuator for movement between said first and second limit positions.

17. The switch according to claim 16 wherein said conductive lost motion means comprises a coil compression spring acting between a portion of said actuator below its axis of pivotal movement and said movable contact, said actuator having a depending portion for retaining said spring so that it comprises the sole lost motion connectortherebetween.

18. The switch according to claim 17 wherein said upper end of said one fixed contact has a C-shaped offset portion with the upper leg of the C-shape defining said conductive abutment.

19. The switch according to claim 17 wherein said resistor circuit includes a resistor, one end of said resistor defining said portion of said circuit for engaging said conductive abutment.

20. The switch according to claim 19 wherein said resistor circuit includes a resistor provided in said actuator and a conductive lead connecting said resistor to said lamp, one end of said resistor to said lamp, one end of said resistor which is opposite said end connected to said lamp by said lead, which said one resistor end defines said portion of said resistor circuit for engagement with said conductive abutment when said actutor is in its first limit position.

21. The switch according to claim 20 further including a second conductive lead connecting said lamp to an upper end of said spring, said actuator depending portion engaging said movable contact to cause it to bridge said certain fixed contacts and to close said circuit for said lamp and resistor through engagement between said upper end of said one fixed contact and said resistor.

22. An electric switch as set forth in claim 13 wherein actuator has a downwardly open recess for said resitor, said resistor recess being spaced from said lamp recess so that said recesses are provided adjacent opposite ends of said actuator and on either side of said depending central portion, said resistor recess defined by opposed concave surfaces of axially elongated generally cylindrical contour and oriented at an acute angle with respect to one another so that one said concave cylindrical surface serves to guide the resistor into place during insertion in said recess and the other siad concave cylindrical surface having a portion inclined with respect to said one surface and spaced therefrom so that after insertion said resistor can be pivoted about its inner end until its outer end abuts said other concave cylindrical surface, and said other surface having resistor retention lips associated therewith to secure said resistor in said recess by engagement with said resistor outer end.

23. In a switch as defined in claim 22 wherein said depending central actuator portion comprises a post and a conductive spring received on said post, one end of said spring engaging said movable contact and an opposite end of said spring received in an annular recess defined by said actuator in concentric relation to said depending post, lamp leads for said lamp, one lamp lead connected to said spring opposite end and a second lamp lead connected to said resistor inner end.

24. In a switch as defined in claim 23 wherein said acutator comprises a rocker of light transmitting plastic and having a downwardly open recess with sides, ends, and a bottom wall, said resistor recess and lamp recess defined by depending integrally formed webs connected to said bottom wall and defined in part by said ends of said actuator, and said annular recess also defined by an annular web integrally connected to said bottom wall, said lamp recess defining web and said annular spring recess defining web having aligned V-shaped slots to receive and locate said lamp lead connected to said spring and a second V-shaped slot in said lamp recess web to receive and locate said second lamp lead.