US3715527A

US3715527A - Rotary switch with double nosed contacts fixedly secured to stator section

Info

Publication number: US3715527A
Application number: US00148358A
Authority: US
Inventors: F Trevisiol; M Bergonzi
Original assignee: AMP Inc
Current assignee: TE Connectivity Corp
Priority date: 1970-06-27
Filing date: 1971-06-01
Publication date: 1973-02-06
Anticipated expiration: 1990-02-06
Also published as: AT309580B; CA923951A; BE768939A; GB1297353A; JPS471529A; SE372129B; NL7108262A; FR2099948A5; DE2129722A1; ES392397A1

Abstract

A rotary switch includes a base plate having spaced holes each of which receives an electrical contact. A wiper arm is arranged to wipe contact surfaces of the contact projecting out of the holes. Each contact has a portion for connection to a conductor and a contact portion for engagement with the wiper arm. The contact portion has a part shaped as a channel having sides and a base. Two extensions project from the ends of the channel sides, the extensions bending back to form at the bends, contact surfaces disposed generally perpendicularly to the travel path of the wiper arm. The ends of the extensions are formed as spring tongues which are arranged to snap behind shoulders provided in the associated hole to prevent withdrawal of the contact.

Description

\ ie tt n91 Trevisiol et al.

[ 1 Feb.6,1973

[54] ROTARY SWITCH WllTH DOUBLE NOSED CONTACTS FIXEDLY SECURED T0 STATOR SECTION [75] Inventors: Franco Trevisiol; Mario Bergonzi, both of Turin, Italy [73] Assignee: AMIP Incorporated, Harrisburg, Pa.

[22] Filed: June 1, 1971 [21] Appl. N0.: 148,358

[30] Foreign Application Priority Data June 27, I970 Italy ..26693 A/7O [52] US. Cl ..200/ll K, 200/166 BH [5]] lint. CI. ..I'I01h 19/58, I-IOlh 2l/78 [58] Field of Search ..200/l66 BH, 8 R, 8 A, 11 G,

ZOO/ll J, 11 K [56] References Cited UNITED STATES PATENTS Bock et al. ..200/l66 BH 2,848,563 8/1958 Berkeley et al. ..200/ ll K Primary Examiner-J. R. Scott Attorney-william J. Keating [57] ABSTRACT A rotary switch includes a base plate having spaced holes each of which receives an electrical contact. A wiper arm is arranged to wipe contact surfaces of the contact projecting out of the holes.

Each contact has a portion for connection to a conductor and a contact portion for engagement with the wiper arm. The contact portion has a part shaped as a channel having sides and a base. Two extensions project from the ends of the channel sides, the extensions bending back to form at the bends, contact surfaces disposed generally perpendicularly to the travel path of the wiper arm. The ends of the extensions are formed as spring tongues which are arranged to snap behind shoulders provided in the associated hole to prevent withdrawal of the contact.

3 Claims, 3 Drawing Figures ROTARY SWITCH WITH DOUBLE NOSED CONTACTS FIXEDLY SECURED TO STATOR SECTION The invention relates to a rotary switch assembly and to an'electrical contact for use in the rotary switch.

Rotary switches may be used to control the lights and turning indicators of motor vehicles. One known rotary switch comprises a wiper bladewhich moves across a series of contacts which each comprise a ring terminal riveted to a switch plate, the wiper blade making contact with the head of one of the rivets to complete any particular circuit. This construction suffers from the defect that if it becomes necessary to replace a contact,

because of breakage of the wires connected to the contact or for some other reason, it is necessary to remove the existing rivet and 'then to rivet a new terminal in position.

According to the invention, a switch assembly comprises a base plate over a surface of which travels a rotatable switch wiper arm, a plurality of through holes spaced apart in the travel path of the wiper arm, each through hole receiving an electrical contact having a wire connecting portion and a contact portion which is of channel section comprising a base and side walls, the side walls of the contact portion each having an end extension bent back upon itself to form, at the bend, a contact surface projecting beyond the base plate surface for contact with the wiper arm, each contact having forward and rearward movement stop means to retain it in position in a through hole in the switch base plate.

According to a further aspect of the invention, an electrical contact, for use in a rotary switch, comprises a wire connecting portion and a contact portion, the

contact portion being a channel section comprising av base and sidewalls, the side walls of the contact each having an end extension bent back upon itself to form, at the bend, a contact surface for contact with a wiper arm of the rotary switch, and forward and rearward movement stop means to retain it in position in a through holein the switch base-plate. v

The invention will now bedescribed with reference to the accompanying drawings, in which:

FlG. l is a diagrammatic perspective view of a rotary switch, parts being cut away to show an electrical 'contact of the invention.

FIG. 2 is a perspective view on an enlarged scale of an electrical contact of FIG. 1; and

FIG. 3 is a partial section along Ill-lII of FIG. 1 on an enlarged scale.

The rotary switch 10 comprises a base'plate ll having a top surface 12 and a bottom surface 13. A plurality of spaced through holes 14 communicating with both

surfaces

12 and 13 is provided near the circumference 15 of the base plate 11. Each through hole 14 receives contact 16 has integrally formed

ferrules

21 and 22 which are crimped about the core 23 and the insulation 24, respectively, of an electrical wire generally referenced 25, the ferrule 21 being integrally connected to a contact portion 26. The contact portion 26 is generally channel-shaped in section adjacent the ferrule 21, having a base 27 and two upstanding side walls 28. Extending from respective side walls 28 at the ends remote from the ferrule 21 are two curved extensions 29. The two extensions 29 are curved in mutually opposite senses such that they converge forward of the base 27, abut along a short section 31, then diverge and finally bend back upon themselves and away from each other at bends 32 to form spring tongues 33 extending towards and axially aligned with the side walls 28. The spring tongues 33 have free ends 34.

The extensions 29 are relieved adjacent the base 27 to define a forward channel-shaped stop 35 formed by the free edge of the base 27 and short portions of the side walls 28.

With reference to FIGS. 1 and 3, each through hole 14 in the baseplate 11 is rectangular in cross-section having a first wall 37 radially outwardly spaced from a second wall 38, and having two approximately radially extending walls 39 (only one of which is shown in FIG. 3). The wall 38 is flat but the wall 37 has a relatively narrow portion 37a (in the radial direction) adjacent the surface 12 joined to a relatively wide portion 37b adjacent the surface 13 at a shoulder 40 which faces the end of the through hole 14 in communication with the surface 13. The walls 39 each have a shoulder 41 facingthe end of the through hole 14 which is in communication with the surface 12, to define a relatively narrow portion 39a (in the peripheral direction) adjacent the surface 13 and a relatively wide portion 39b adjacent the surface 12. I

To position an electrical contact 16 in a through hole 14, the contact is inserted into that end of the hole 14 which communicates with the surface 13, the spring tongue 33 of the contact being compressed by the walls 39 in the portion 390. The contact 16 is pushed further into the hole 14 until the spring tongues 33 spring apart into the portion 39b, the free ends 34 of the spring tongue 33 locking behind the shoulders 41 to prevent withdrawal of the contact 16. Further forward movement of the electrical contact 16 is prevented by engagement of the stops 35 on the contact with the shoulder 40 on the wall 37. When the electrical contacts 16 are so positioned in respective through holes 14 the extensions 29 project above the surface 12 of the base plate 11. As the wiper arm 17 travels its ar'cuate path it engages the contacts at their bends 32.

To remove an electrical contact 16 from the switch 10 the spring tongues 33 of the extensions 29 are pressed together so that their free ends 34 are freed from the shoulder 41, thus allowing the electrical contact 16 to be withdrawn rearwardly from the through hole 14.

Contaminants, such as grease and dirt, on the contact surface at the free end of the electrical contact 12 are wiped off by the action of the wiper blade, the contaminants being pushed into the space between the end extensions or into one of the spaces between the end extensions and the side walls of the hole 14.

We claim:

l. A switch assembly comprising a base plate, having a front surface and a rear surface over a surface of which travels a switch wiper arm rotatable over the front surface, a contact portion on the wiper arm, and a plurality of through holes provided in the baseplate and spaced apart in the travel path of the wiper arm contact portion, each through hole receiving a stationary electrical contact having a wire connecting portion and a contact portion which is a channel section comprising a base and side walls, the side walls of the contact portion each having an end extension bent back upon itself away from the other end extension on the same-stationary contact to form a spring tongue having a free end and, at the bend, a contact surface projecting beyond the base plate front surface for contact with the wiper arm contact portion, the bend being disposed generally perpendicularly to the travel path of the wiper arm contact portion, flexure of the spring tongues allowing insertion direction from the rear surface towards the front surface beyond first shoulders in the respective hole, the free ends of the spring tongues engaging the first shoulders to prevent withdrawal of the contact in the rearward direction.

2. A switch assembly as claimed in claim 1, in which the end extensions of each contact are curved in mutually opposite senses, such that they converge forwardly of the channel base, mutually abut along a short section and diverge to meet the bends in the end extensions.

3. A switch assembly as claimed in claim 2, in which the base of the channel section contact portion of each contact has a forward stop engageable with a second shoulder in the respective hole to limit forward movement of the contact in the hole.

Claims

1. A switch assembly comprising a base plate, having a front surface and a rear surface over a surface of which travels a switch wiper arm rotatable Over the front surface, a contact portion on the wiper arm, and a plurality of through holes provided in the baseplate and spaced apart in the travel path of the wiper arm contact portion, each through hole receiving a stationary electrical contact having a wire connecting portion and a contact portion which is a channel section comprising a base and side walls, the side walls of the contact portion each having an end extension bent back upon itself away from the other end extension on the same stationary contact to form a spring tongue having a free end and, at the bend, a contact surface projecting beyond the base plate front surface for contact with the wiper arm contact portion, the bend being disposed generally perpendicularly to the travel path of the wiper arm contact portion, flexure of the spring tongues allowing insertion direction from the rear surface towards the front surface beyond first shoulders in the respective hole, the free ends of the spring tongues engaging the first shoulders to prevent withdrawal of the contact in the rearward direction.

2. A switch assembly as claimed in claim 1, in which the end extensions of each contact are curved in mutually opposite senses such that they converge forwardly of the channel base, mutually abut along a short section and diverge to meet the bends in the end extensions.