GB2214593A

GB2214593A - Remote control mechanism

Info

Publication number: GB2214593A
Application number: GB8801268A
Authority: GB
Inventors: Colin Eric Duncan; Michael Robinson
Original assignee: Bowden Controls Ltd
Current assignee: Bowden Controls Ltd
Priority date: 1988-01-21
Filing date: 1988-01-21
Publication date: 1989-09-06
Also published as: GB8801268D0

Abstract

A control member (1,2,3) for opening an engine choke or other element is axially displaceable relative to a fixed housing (6) against a resistance imposed by a spring (13) acting against a transverse bar (14) which bears against the control member. The housing (7) defines a cavity which opens transversely with respect to the axis of the control member (1,2,3) and is provided with guideways (17,17') along which the opposed ends of the bar (14) are slidable. For assembly purposes, the bar (14) is insertable from the open side of the cavity into a position in which the control member 1,2,3 can be axially threaded through the housing, beneath the bar. The spring (13) can form part of or make contact with an electrical terminal (9, 11) via which an electrical circuit is closed when the control member (1,2,3) is displaced to bring the bar (14) into contact with an electrically conductive part (2) of such control member. <IMAGE>

Description

Remote Control Mechanism This invention relates to a remote control mechanism comprising a control member which transmits force by axial motion.

The invention is particularly but not exclusively concerned with such mechanisms wherein the control member is or includes a flexible wire or cable which is slidable within a guiding sleeve or conduit.

It is sometimes necessary to provide for axial displacement of an axially displaceable control member relative to a housing for a spring-loaded element which co-operates with the said control member to determine one or more particular operative positions thereof and/or to close an electrical circuit for operating a signal indicative of such an operative position. This necessity arises for example in relation to certain vehicle engine choke control assemblies. in such assemblies the housing may be connected to the guiding sleeve or conduit of the choke control member which comprises a flexible wire or cable.

It is an object of the invention to provide a mechanism whch is assembled to a said housing and spring-loaded element in a conveninent and fur.ctionally efficient manner.

According to the present invention, the housing has opposed end openings through which the control member can be threaded and defines a cavity opening transvrscly with respect to the axis of said openings; said cavity has in opposed sides thereof guideways for the ends of a bearing element which is slidable along said guideways against the biasing force of spring means by which such bearing element is urged against the said control member.

The form of the bearing element and the manner in which it is located makes assembly easy in comparison for example with a more usual ball bearing used in some choke control assemblies.

The bearing element can for example be in the form of a bar of circular cross-sectional profile so that it forms a roller which can make rolling contact with the control member as the latter is axially displaced.

For positional location purposes the control member can have one or more indentations. recesses or the like into which the bearing element springs when the said control member reaches a predetermined position.

The invention is pf particular benefit in cases in which the bearing element is required to serve as an electrical contact. The bearing element can be made of brass or some other material of good electrical conductivity and so can provide for more efficient electrical connection than would be possible by means of a ball bearing. which latter would necessarily be more expensive.

The bearing element is preferably spring loaded by means of a leaf spring.

According to another optional but nevertheless very advantageous feature the assembly includes an electrically conductive plate which is disposed within the housing but has an end portion which projects externally thereof through an aperture in the casing to form an external terminal. the plate having a shoulder which pre-+nts its withdrawal from the housing through such opening and being formed so that its said terminal-forming end portion can be threaded through said aperture from inside the housing as the plate is inserted into the housing via the mouth of its cavity.The said electrically conductive plate may be formed so that a part of it serves as a leaf spring as aforesaid. or the leaf spring may be a separately fabricated member which is connected to or simply bears against said plate under the energy which is stored in said spring and urges the bearing element against the force-transmitting member.

An embodiment of the invention. selected by way of example. is illustrated in the accompanying drawings in which: Fig. 1 is a cross-sectional elevation of part of a choke control mechanism according to the invention; and Fig. 2 is an underplan view of a part of the mechanism including the housing.

The illustrated mechanism incorporates a composite choke control member 1 comprising a flexible wire cable 1, a rigid end rod 2 attached to such cable. and a control knob 3 of insulating polymeric material which is moulded onto an end portion 2' of the rod 2. such end portion being of hexagonal cross-section. The cable 1 is slidable within a guiding conduit 4 fitted with a liner tube 5.

A one-piece moulding 6 forming a housing 7 with a tubular extension 8 is connected by such extension to the conduit 4.

The housing 7 defines a cavity which is open at the bottom.

Within this cavity there is a metal plate 9 having beyond a shoulder 10 an end portion 11 which projects through an opening 12 in the housing so as to serve as a terminal for connnection into a circuit operating a warning lamp (not shown). A leaf spring 13 bears against the plate 9 and against a bearing element 14 in the form of a circular section brass bar. When the choke control is in its illustrated inoperative position the leaf spring presses the bar 14 against the stem 15 of the insulating control knoh 3, the bar being then in register with a receptive peripheral groove 16 on said stem. The end of the bar 14 are within opposed guide grooves 17,17''in the side walls of the housing.The guide grooves guide the bar in bodily motion parallel with itself, towards and away from the bottom of the cavity where plate 9 is located. The plate 9 has lateral tab portions 9',9" which also fit into the fit into the guide grooves 17,17'.

When the choke is operated by pulling out the control knob 3 the bar 14 is pushed up against the biasing force of spring 13 by the end of the knob stem 15 as it is pulled under the bar and the bar then springs back into contact with the metal rod 2 and thereby completes the warning lamp circuit. There are two peripheral grooves 18,19 in the rod 2 into which the bar 13 becomes pressed when they move into register with the bar so that the operator senses when the control reaches those predetermined operating positions.

The assembly of the control is easy. The plate 9 can be brought into its working position from an inclined position suggested by the broken lines in Fig. 1 by pushing the plate forwardly to advance its terminal forming end portion 11 through the opening 12 in the housing and swinging the other end of the plate upwardly against the bottom of the housing davity. The leaf spring 13 is then inserted into the housing cavity, followed by the bar 14. The housing is formed with short integral tongues 20,21' in the guide grooves 17,17'. The bar 14 is pushed past these tongues causing their deflection and they then recover to serve as stops which hold the bar in a position in which the cable and then the end rod 2 and control knob stem 15 can pass beneath the bar during the subsequent operation of threading the cable 1 through the housing and its tubular extension and into the conduit 4. When the rod 2 reaches the bar 14 during that operation the bar is pressed up against the resistance of the leaf spring 13. The assembly is then complete.

A plate can be provided for closing the bottom of the housing cavity after the assembly but that is not necessary.

Claims

1. A remote control mechanism comprising a control member which transmits force by axial motion, such member being axially displaceable relative to a housing wherein there is a spring-loaded element which co-operates with the said control member to determine one or more particular operative positions thereof and/or to close an electrical circuit for operating a signal indicative of such an operative position, characterised in that the housing has opposed end openings through which the control member can be threaded and defines a cavity opening transversely with respect to the axis of said openings; and said cavity has in opposed sides thereof guideways for the ends of a bearing element which is slidable along said guideways against the biasing force of spring means by which such bearing element is urged against the said control member.

2. A mechanism according to claim 1, wherein the bearing element is in the form of a bar of circular cross-sectional profile so that it forms a roller which can make rolling contact with the control member as the latter is axially displaced.

3. A'mechanism according to claim 1 or 2, wherein the control member has one or more indentations, recesses or the like into which the bearing element springs when the said control member reaches a predetermined position.

4. A mechanism according to any preceding claim. wherein the bearing element is made of brass or some other material of good electrical conductivity and serves as an electrical contact for closing a warning signal circuit when the control is operated.

5. A mechanism according to any preceding claim. wherein the bearing element is spring loaded by means of a leaf spring.

6. A mechanism according to any preceding claim, wherein the housing has retaining tongues which allow passage of the ends of said bearing element along said guideways when such element is inserted into the housing but which recover to retain the bearing element in a position allowing threading of the control member through the housing.

7. A mechanism according to any preceding claim. wherein the assembly includes an electrically conductive plate which is disposed within the housing but has an end portion which projects externally thereof through an aperture in the casing to form an external terminal, the plate having a shoulder which prevents its withdrawal from the housing through such opening and being formed so that its said terminal-forming end portion can be threaded through said aperture from inside the housing as the plate is inserted into the housing via the mouth of its cavity.