US 3842223 A
An electrical switch comprising a body having pivotally mounted thereon an operating member.
Description (OCR text may contain errors)
[ Oct. 15, 1974 LEVER OPERATED SWITCH HAVING ADJUSTABLE CONTACT GAP  Inventor: Stephen James Bird, Burnley,
England  Assignee: The Lucus Electrical Company Limited, Birmingham, England  Filed: May 7, 1973  Appl. No.2 357,707
 Foreign Application Priority Data May 18, 1972 Great Britain 23309/72  U.S. Cl. ZOO/61.58 B, 200/166 M, ZOO/61.14  Int. Cl. HOlh 3/16, B65h 25/14  Field of Search..... 200/61.58 B, 153 R, 166 M,
2,837,616 6/1958 .laidinger 200/166 M 3,555,229 1/1971 3,576,416 4/1971 Good 200/166 M 3,670,119 6/1972 Gebhardt 200/85 A Primary ExaminerRobert K. Schaefer Assistant ExaminerGerald P. Tolin Attorney, Agent, or FirmHolman & Stern [5 7 ABSTRACT An electrical switch comprising a body having pivotally mounted thereon an operating member.
A movable contact is supported by the operating member and is engageable with a fixed contact on the body to complete an electrical circuit through the switch. A spring urges the operating member to a rest position and there is provided a screw adjuster associated with the fixed contact for adjusting the position of the fixed contact on the body. Adjustment of the position of the fixed contact relative to the body adjusts the displacement of the operating member which is necessary to operate the switch.
3 Claims, 2 Drawing Figures PATENTEU 51974 3.842.223
LEVER OPERATED SWITCH HAVING ADJUSTABLE CONTACT GAP This invention relates to electrical switches.
An electrical switch according to the invention comprises a body, an operating member pivotally mounted on the body and carrying a movable contact, a fixed contact on the body and engageable by the movable contact to complete an electrical circuit through the switch, resilient means urging the operating member to a rest position, and screw adjustment means associated with the fixed contact whereby the position of the fixed contact on the body can be altered so as to adjust the displacement of the operating member necessary to operate the switch.
Preferably said screw adjustment means includes a screw threaded shaft rotatable in the body, means resisting axial movement of the shaft, a nut in screw threaded engagement with the shaft and carrying said fixed contact, and means resisting angular movement of the nut.
Conveniently the operating member is an elongated strip of material pivotally mounted intermediate its ends, on the body.
Preferably said operating member includes a conductive end portion which defines said movable contact, the body supporting a terminal member which is electrically connected to said movable contact by way of a conductive spring bearing at one end against a part electrically connected to the terminal and at its other end against said portion of the operating member.
Conveniently said conductive spring constitutes said resilient means urging the operating member to a rest position.
In the accompanying drawings,
FIG. 1 is a sectional view of a switch in accordance with one example of the invention, and
FIG. 2 is a view similar to FIG. 1 of a modification of the switch shown in FIG. 1.
Referring first to FIG. 1 of the drawings the switch includes a moulded synthetic resin body 11 arranged in any convenient manner to be secured to the frame of a vehicle seat. At one end the body 11 is formed with a recess 12 the recess 12 being closed by an insulating cover 13 secured to the body 11. Extending into the body 11 from the base of the recess 12 is a first passage 14 within which is slidably mounted an L-shaped fixed contact 15. One limb of the contact 15 extends transverse to the passage 14, and is formed with a screwthreaded bore, so that the limb of the contact 15 defines a nut 15a. Engaged with the nut 15a is a screwthreaded shaft 16 defined by the shank of a bolt. The headed end of the bolt projects from the end of the body 1] remote from the cover 13 and secured to the head of the bolt is a moulded synthetic resin knob 17. A spring 18 encircles the shaft 16, and acts between the nut 15a and the body 11 to urge the knob 17 downwardly into engagement with the surface of the body 11. The fixed contact 15 is held against rotation relative to the body 11 by the walls of the passage 14, and accordingly rotation of the knob 17 causes axial movement of the fixed contact 15 towards or away from the cover 13. A terminal member 19 is secured to the cover 13, and a conductive spring 21 acts at one end against the nut 15a, and at its other end against a part 19a electrically connected to the terminal 19. A lead 22 constitutes the external combustion to the terminal 19, and
thus the spring 21 electrically interconnects the lead 22 and the contact 15. Although the position of the contact 15 relative to the body 11 is adjustable by means of the screw adjustment mechanism 15a, l6, 17, as will be described later the contact 15 is the fixed contact of the switch.
Extending into the recess 12 by way of a narrow gap defined between the cover 13 and a projection 11a on the body 11 is an elongated operating member 23. The operating member 23 is defined by an elongated strip of spring steel, the end portion of the operating member 23 within the recess 12 terminating adjacent the fixed contact 15, and defining a movable contact 24 of the switch. A spring 25 housed within a second passage in the body 11 acts on the operating member 23 to urge the inner portion of the operating member into facial contact with the inner surface of the cover 13. The spring 25 bears at one end against the operating member 23, and at its other end against a'member 26 electrically connected to an external terminal 27 in turn electrically connected to a lead 28. Thus the spring 25 completes an electrical circuit between the lead 28 and the moving contact 24, and when the moving contact 24 is moved into engagement with the contact 15, then a circuit is completed through the switch between the leads 22 and 28.
In order to complete an electrical circuit through the switch the outer free end of the operating member 23 is moved in a counter-clockwise direction, to cause the operating member 23 to pivot about the edge of the cover 13 adjacent the projection 11a. Such pivotal movement of the operating member 23 takes place against the action of the spring 25, and moves the contact 24 into engagement with the contact 15. Upon release of the operating member 23 the spring 25 restores the operating member to a position wherein the inner end of the operating member is in facial contact with the inner surface of the cover 13 and the circuit is broken.
The switch is particularly intended for use in a road vehicle, where anelectrical circuit is to be controlled in accordance with whether or not a seat of the vehicle is occupied. in such an arrangement, the body 11 is rigidly secured to the frame of the seat, and the free, external end of the operating member 23 engages the under surface of the squab of the seat. Thus when the seat is unoccupied the member 23 is urged by the spring 25 to its rest position, and the circuit through the switch is broken. However, when a person sits on the seat, the persons weight causes downward movement of the squab of the seat, and accordingly the operating member 23 is pivoted in a counter clockwise direction to complete the circuit through the switch. The degree of downward movement of the squab of the seat will be determined by the weight of the person occupying the seat, and the rigidity of the squab. The adjustability of the position of the fixed contact permits the switch to be adjusted to accommodate differences in deflection of individual seats, and the weight of the occupant of the seat. The circuit controlled by the switch can for example be part of a system for ensuring that the engine of the vehicle cannot be started in the event that an occupant of the vehicle does not have his seat belt fastened. For example, considering the front passenger seat of the vehicle then it is necessary to detect whether or not there is a passenger occupying the passenger seat. In the event that a passenger is occupying the seat then the engine of the vehicle cannot be started until the passenger fastens his seat belt. However, in the event that no passenger occupies the seat the circuit controlled by the switch is broken, and the system permits the engine to be started even though the passenger seat safety belt is not fastened. It will therefore be appreciated that the facility of adjusting the deflection of the operating member necessary to operate the switch is an important facility.
The switch shown in FIG. 2 differs from the switch shown in FIG. 1 purely in the positioning of the screw adjustment mechanism of the contact 15. In the arrangement shown in FIG. 2 the screw-threaded shaft 16 is journalled for rotation in the cover 13 rather than in the body 11, and accordingly the terminal 19, 19a is carried by the body rather than the cover. In the FIG. 2 arrangement of course the leads 22, 28 extend from the same side of the body 11, and in some instances this may facilitate mounting of the switch.
1. A lever operated electrical switch comprising, a body an operating lever, said operating lever being defined by a conductive strip, means pivotally mounting said strip on said body with a first portion within said body, and a second portion projecting from said body,
a movable electrical contact on said first portion of said strip, a fixed electrical contact carried by the body, and engageable by said movable contact to complete an electrical circuit through the switch, a first terminal member on the body, a conductive, resilient member electrically interconnecting said first terminal member and said conductive strip, and urging said conductive strip to pivot relative to the body to a position wherein said movable contact is spaced from said fixed contact, and, screw adjustment means associated with said fixed contact, whereby the position of said fixed contact on the body can be altered so as to adjust the displacement of said second portion of said conductive strip which is necessary to engage said movable contact with said fixed contact.
2. An electrical switch as claimed in claim 1 wherein said movable contact is an integral part of said first portion of said conductive strip.
3. An electrical switch as claimed in claim 1 wherein said screw adjustment means includes a screw threaded shaft rotatable in the body, means resisting axial movement of the shaft, a nut in screw threaded engagement with the shaft and carrying said fixed contact, and
means resisting angular movement of the nut.