US3346707A

US3346707A - Multi-position electrical switch with improved guide rail and movable contact structure

Info

Publication number: US3346707A
Application number: US549869A
Authority: US
Inventors: Bock Willy; Mutschler Erich; Theurer Karl-Heinz
Original assignee: SWF Spezialfabrik fuer Autozubehoer Gustav Rau GmbH
Current assignee: SWF Auto Electric GmbH
Priority date: 1965-12-31
Filing date: 1966-05-13
Publication date: 1967-10-10
Anticipated expiration: 1984-10-10
Also published as: BE691422A; GB1138221A; FR1505203A; NL6609840A; DE1248137B

Description

Oct. 10, 1967 w BOCK ET AL 3,346,707

MULTI-POSITION ELECTRICAL SWITCH WITH IMPROVED GUIDE RAIL AND MOVABLE CONTACT STRUCTURE Filed May 13, 1966 2 Sheets-Sheet 1 i 5 F 1 '1 L1 3 &\\\\ A 7 I QT 9 I3 I40. I

In ven tors W/ZL Y 504% EEK/4 Hurst/{LE2 KAEZ-HEM/z MFA/25R ATTORNEY Oct. 10, 1967 MULTI-POSITION ELECTRICAL SWITCH WITH IMPROVED GUIDE RAIL Filed May 13, 1966 W BOCK ETAL 3,346,707

AND MOVABLE CONTACT STRUCTURE 2 Sheets-Sheet 2 Fig.9

a ll! III In ventors w/y Boa/r ERIC/l MUTSCHLEE ITAEZ-I/E/NZ fl/E'UEE/Z ATTORNEYS United States Patent ()fiice No. 549,869 Claims priority,

application Germany, Dec. 31, 1965,

S 101,288 13 Claims. (Cl. 2008) ABSTRACT OF THE DISCLOSURE An electrical switch including a movable contact carried on a rotatable arm which rotates through an arc to successively contact two or more fixed contacts is disclosed herein. The rotary contact is manipulated by means of a hand knob and it carries a cylinder in a recess thereof which is biased outwardly to effect contact between adjacent fixed contact terminals which are disposed around its arcuate path of movement.

LIIl accordance with one inventive feature, the fixed terminals are formed by projections on the interior of a housing which carries a slot directly adjacent the projection. An electrically conductive member includes a contact portion which is wrapped around the projection and a terminal portion which is directed through the slot of the housing and offset in respect to the slot to anchor the contact member in position. The contacts may be of a variety of different configurations, for example bar-shaped, rectangular or polygonal.

This invention relates in general to electrical switch construction and to a method of constructing such a switch, and particularly to a new and useful electrical switch for use in vehicles which includes a rotary switch element having a bias contact member which may be moved into engagement with a selected pair of a plurality of contact bodies which are inserted into the housing from the exterior and which are arranged in association with an interior formation around which it is positioned to provide a resiliently mounted stationary contact assembly.

The electrical switch of the present invention is particularly designed for use in motor vehicles and includes a rotary switch part which has a contact element at the end which protrudes into the switch housing. The rotary switch part can be connected successively with several contact pairs, which contact pairs are made of a plurality of spaced individual contacts which are connected with plugs outside the switch housing. Normally switches of this character are designed so that bolts or hollow rivets are arranged in the switch housing as contacts which are nested with cable connections arranged outside the switch housing, for example plugs. Due to this form of connection of the contacts with the plugs, a zone with additional transfer resistance is obtained which reduces the efiiciency of the switch. In addition, the use of hollow rivets as contacts has the disadvantage that several openings must be provided in the switch housing which cannot be fully closed so that dirt and dust can easily penetrate and mix with the contact grease which is applied to the contacts and on the switch elements. This contaminated contact grease causes the contact elements to stick and thus produces troubles in the operation of the switch.

A further disadvantage of the known switches is that the contact bolts or hollow rivets cannot be adjusted once 3,346,7'07 Patented Oct. 10, 1967 they have been assembled. If it should develop that there is an improper position between the contact element and the individual pairs of contacts, it is only a point contact instead of a satisfactory line contact so that a very high transfer resistance appears which will make the switch useless in a short period.

In accordance with the present invention, there is provided a switch which does not have the above-mentioned disadvantages and which permits an easy assembly with a satisfactory position of the contact elements. In accordance with the invention, the contact bodies and their respective outer plugs are designed as one-piece plug contact elements which can be secured directly on the switch housing. The fastening of these elements is accomplished in accordance with the invention by means of a crossed lap joint. The interior portion of the contact plug which is adapted to be arranged within the housing is made of a generally U-shaped configuration, with the legs on each side of the U-shaped portion being arranged substantially perpendicular to the broad surface of the outer plug portion which is located on the exterior of the housing. The plug contacts are also provided with lateral notches so that the edge of the U-shaped contact body facing the housing bottom is tooth-shaped toward the end of the two U-shaped contact bodies of the construction. The narrow surfaces of the plug facing the housing bottom which are formed by notches are designed as inclined surfaces, the lowest points of the two inclined surfaces bearing on the lateral narrow faces of the plug. The leg faces of the U-shaped contact body within the housing are inclined toward each other, the wider openings facing the housing bottom so that they can bear on projections provided in the housing which are designed in accordance with the inner form of the contact body.

In accordance with a further feature of the invention, slots are provided on the interior of the housing adjacent the formations thereof which are arranged substantially perpendicularly to the broad surfaces of projections which are formed on the interior of the housing. The terminal plug members may thus be inserted through the slots of the housing, and the U-shaped interior portions may be oriented around the projections. In this manner, the plug elements may be inserted into the housing under a biased potential.

The contact body may be formed of any desired gene-rally U-shaped configuration and thus may be formed with a rounded surface, flat or acute angle surface corresponding to the required switching power to be formed between the movable contact and the U-shaped contact body.

Because of the unique construction of the housing and the contact terminal elements, the assembly of the parts is very simple to carry out. A satisfactory position of the contact body is always assured by the location of the abutment on the interior of the housing.

Accordingly it is an object of the invention to provide an improved multi-contact switch element which includes a plurality of spaced stationary contacts which are formed by a contact terminal member which includes an interior substantially U-shaped portion which is adapted to engage around a projection on the interior of the housing and a flat extending portion forming a terminal which extends through the housing.

A further object of the invention is to provide a method of forming a switch which includes forming a housing with a plurality with spaced projections and with a slot through the housing defined alongside one end of the projections, comprising inserting a plurality of contact body members through the slots and wrapping them around the projections on the interior of the housing, and

connecting the exterior terminal parts to electrical circuit connections.

A further object of the invention is to provide a rotary switch particularly for use in automobiles which includes a movable rotary contact member and a plurality of stationary contact elements arranged in a row with the stationary contact elements being formed from a contact member which includes a U-shaped interior portion and an external portion extending through a slot of the housing providing a connection terminal therefor.

A further object of the invention is to provide a rotary switch which is simple in design, rugged in construction and economical to manufacture.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

In the drawings:

FIG. 1 is a sectional view of a switch constructed in accordance with the invention taken along the line 11 of FIG. -2;

FIG. 2 is an elevational view of the interior of the switch with an end cover removed;

FIG. 3 is an end elevational view of the switch indicated in FIG. 1 taken in the direction of the arrow A;

FIG. 4 is a partial sectional view taken on the line 4-4 of FIG. 2;

FIG. 5 is a section taken on the line 55 of FIG. 4 but indicating the terminal plug before it is in a seated position as indicated in FIG. 4;

FIG. 6 is a development of the terminal plug and housing end and side walls indicated in FIG. 4; and

FIGS. 7, 8 and 9 are somewhat schematic plan views indicating the contact between the movable roller contact and the contact terminal member of various embodiments of the invention.

Referring to the drawings in particular, the invention embodied therein as indicated in FIGS. 1 to 6 comprises a switch housing 1 having a rotary switch part 2 arranged therein and journaled for rotation. The part 2 is provided with a tubular pin or extension portion 3 which extends outwardly through an opening in a side wall of an extension portion 1a of the housing 1. A knob 4 is threaded onto the pin 3 and it is provided with a bore which aligns with a bore defined in the extension 3 and the part 2 to accommodate a switching bar 6. The switching bar 6 may be reciprocated axially by pushing a push-button element 5, and it is normally biased to an outward position by means (not shown). The switching bar is connected to means (not shown) for controlling the discharge of liquid from a liquid tank (not shown).

The part 2 is provided with a cavity 9 in which is positioned a compression spring 7 which biases a contact roll member or cylinder 8 outwardly.

In accordance with the invention, the housing is provided with a wall portion or end wall 14 which is formed with a plurality of spaced slots 10. Projections 17 are formed alongside each slot preferably on an adjacent horizontal wall 14a. The projections 17 may of course be formed on the same wall as the slots as shown in FIG. 6, and they are advantageously arranged so that an end thereof which is advantageously rounded is oriented adjacent the center of the slot 10 and extends substantially perpendicularly thereto. Other arrangements may of course be provided to form outlines of projections as indicated in FIGS. 7, 8 and 9, for example.

A feature of the construction is that contact terminal elements or stationary contact members generally designated 11 are formed with a flat plug or terminal portion 12 which may be easily inserted through the slots 10 to project on the exterior of the housing. The contact members 11 include an interior contact element or contact body portion 13 which is arranged inside the housing which is of generally U-shaped configuration.

In the preferred arrangement, the interior contact body portion 13 is generally U-shaped and is formed with leg wall portions which diverge downwardly to the housing wall and which have a bottom edge of a generally toothshaped configuration which engage the side wall 14 of the housing. The wider spacing between the leg portion 16 is at the bottoms or the portions located directly adjacent the housing wall 14. They are advantageously formed in a conical configuration as indicated best in FIG. 5.

It is generally preferable to arrange the plug portion 12 so that it extends slightly turned from the axis of the U-shaped contact body 13. In the embodiment of FIGS. 1 to 6, the projection extends substantially perpendicular to the slot 10 so that when the plug contact body mem bers 11 are inserted, they are already held under a biased potential in the housing wall 14. This is accomplished due to the angle of the slot in respect to the projection so that the body portion must be twisted slightly in order to effect insertion in the slot. By additional turning of the plug 12, the contact body 13 is then pulled to the housing projection and the inclined surfaces 18 penetrate through the housing wall to form a fir-m fit with the housing wall.

Because of the abutment of the contact body 13 on the projection 17, its position is fixed and an elastic yielding when it comes in contact with the contact roll member is no longer possible. This insures that the desired line contact between the contact roll 8 and the contact body 13 is maintained during the switching process. A point contact which results in adverse high transfer resistances is thus impossible.

The housing 1 is formed with a journal 19 located centrally below the wall 14 which is formed by injection molding on the switch housing and which is advantageously made of a plastic material. The journal 19 holds the base plate 20* and a valve housing (not represented) can be connected with the switch housing for delivering liquid, for example, through wafer-headed rivets. In this manner, the size of the switch can be kept small since there is no space required for the passage of rivets or screws.

FIGS. 7, 8 and 9 represent various forms which the contact body portions 13', 13", and 13" may take for each of the

contact terminal elements

11', 11 and 11". The roller contacts 8, 8 and 8" will engage the terminal elements as indicated.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. An electrical switch including a housing having wall means with a plurality of spaced slots defined in said Wall means, and a contact terminal element including a flat terminal portion extending through a respective slot of the housing and disposed at the exterior of the housing to form a terminal connection, an interior portion located on the interior of said housing forming a contact element, and a projection formed on said housing wall means adjacent each slot, said interior portion of each contact terminal element being engaged around an associated projection.

Z. An electrical switch according to claim 1, wherein said interior portions of said contact terminal elements are substantially U-shaped.

3. An electrical switch according to claim 2, wherein said interior portions of said contact elements have rounded ends.

4. An electrical switch according to claim 1, wherein said interior portion of said contact terminal element is substantially U-shaped and has squared ends.

5. An electrical switch according to claim 1, wherein said interior portion of said contact terminal element is substantially U-shaped and includes oblique end portions and substantially straight leg portions.

6. An electrical switch according to claim 1, wherein said interior projections are formed with tapered sides with a wider dimension at the connection to said interior wall, said interior portion of said contact terminal element being bent around said interior projection sides and one end thereof.

7. An electrical switch according to claim 1, wherein said contact elements are secured on said housing wall by a cross lap joint, said elements having an intermediate cut-away portion between the interior portion and said flat terminal portion having an inclined surface.

8. An electrical switch according to claim 1, wherein said projections form an acute angle with the associated interior terminal portions which are engaged therearound.

9. An electrical switch according to claim 1, wherein said slots are arranged at right angles to the longitudinal axes of said projections.

10. An electrical switch including a housing having wall means with a plurality of spaced slots defined in said wall means, and a contact terminal element including a fiat terminal portion extending through a respective slot of the housing and disposed at the exterior of the housing to form a terminal connection, an interior portion located on the interior of said housing forming a contact element, and a projection formed on said housing wall means adjacent each slot, said interior portion of each contact terminal element being engaged around an associated projection, a rotary switch member rotatably mounted in said housing to permit it to be swung into selective contact between adjacent pairs of said interior portions of said contact terminal elements, said rotary switch member including a swinging arm having a recess therein, a cylindrical contact member positioned in said recess, and spring means biasing said contact member out of said recess into engagement with one of said interior portions of said contact terminal elements.

11. An electrical switch including a housing having wall means with a plurality of spaced slots defined in said wall means, and a contact terminal element including a flat terminal portion extending through a respective slot of the housing and disposed at the exterior of the housing to form a terminal connection, an interior portion located on the interior of said housing forming a contact element, said contact terminal elements interior portions being substantially U-shaped and include straight leg portions arranged on each side of an associated projection.

12. An electrical switch including a housing having wall means with a plurality of spaced slots defined in said wall means, and a contact terminal element including a flat terminal portion extending through a respective slot of the housing and disposed at the exterior of the housing to form a terminal connection, an interior portion located on the interior of said housing forming a contact element, said contact terminal elements including a substantially U-shaped slot formed between said flat terminal portion and said interior portion defining a tooth configuration at the lower interior extremity of said interior portion which engages said housing wall.

13. An electrical switch including a housing having wall means with a plurality of spaced slots defined in said wall means, and a contact terminal element including a flat terminal portion extending through a respective slot of the housing and disposed at the exterior of the housing to form a terminal connection, an interior portion located on the interior of said housing forming a contact element, said slots being disposed at an acute angle with respect to the longitudinal axis of projections formed on said housing wall.

References Cited UNITED STATES PATENTS 2,695,933 11/1954 Daily et al 200-166 3,196,222 7/1965 Maelstaf 200-11 3,225,148 12/ 1965 Sorensen 2001l 3,229,052 1/1966 Silvius et al 200-8 X FOREIGN PATENTS 1,353,172 1/1964 France.

ROBERT K. SCHAEFER, Primary Examiner. J. R. SCOTT, Assistant Examiner.

Claims

1. AN ELECTRICAL SWITCH INCLUDING A HOUSING HAVING WALL MEANS WITH A PLURALITY OF SPACED SLOTS DEFINED IN SAID WALL MEANS, AND A CONTACT TERMINAL ELEMENT INCLUDING A FLAT TERMINAL PORTION EXTENDING THROUGH A RESPECTIVE SLOT OF THE HOUSING AND DISPOSED AT THE EXTERIOR OF THE HOUSING TO FORM A TEREMINAL CONNECTION, AN INTERIOR PORTION LOCATED ON THE INTERIOR OF SAID HOUSING FORMING A CONTACT ELEMENT, AND A PROJECTION FORMED ON SAID HOUSING WALL MEANS ADJACENT EACH SLOT, SAID INTERIOR PORTION OF EACH CONTACT TERMINAL ELEMENT BEING ENGAGED AROUND AN ASSOCIATED PROJECTION.