GB1566286A

GB1566286A - Electrical switches

Info

Publication number: GB1566286A
Application number: GB4799576A
Authority: GB
Original assignee: Preh GmbH
Current assignee: Preh GmbH
Priority date: 1975-11-18
Filing date: 1976-11-17
Publication date: 1980-04-30
Also published as: DE7536528U; IT1064271B; FR2332606B3; FR2332606A1

Description

(54) ELECTRICAL SWITCHES (71) We, WALTER PREH GESELLSCHAFT MIT BESCHRÄNK- TER HAFTUNG, a German Federal Republic body corporate the sole responsible partner in PREH ELEKTROFEIN MECHANISCHE WERKE, JAKOB PREH NACHF. GmbH & Co. formerly known as PREH GLEKTROFEIN MELHANISCHE WERKE, Jakob Preh Nache, of Schweinfurter Strasse 5, Bad Neustadt/Saale, Germany (Fed Rep), do hereby declare the invention, for which we pray that a patent may be granted to us and the method by which it is to be particularly described in and by the following statement: This invention realtes to electrical switches.

According to the invention there is provided a button-operated electrical switch comprising a spring-loaded actuating element movably mounted in a housing and two contact members between which relative movement is produced, to make or break an electrical path through the switch, when the spring loaded actuating element is moved on operation of the switch, wherein one of the contact members comprises a base portion by which it is mounted on said actuating element, and which can pivotally flex through only a limited angular range, and the contact members are arranged so that when the switch is in a closed condition said arm of the one contact member is urged resiliently against the other contact member, and wherein said housing is electrically conductive and is this other contact member.

According to one development the contact member is "J"-shaped, the longer limb including the base portion while the shorter limb is provided by the arm, the latter being connected to the base portion by way of a looped extension.

According to another development, the looped extension is connected to the base portion by way of a further arm. In a further development, the first-mentioned arm has at least one contact projection which is bent over perpendicularly to the plane of the arm.

Preferably, the angle through which the first-mentioned arm can pivot is limited by a retaining device. This retaining device may consist of a retaining projection situated at the free end of the first-mentioned arm and bent over towards the base portion, this retaining projection being fitted in an opening in the base portion, and in the further spring arm when provided, and being bent over into a constriction in the opening, the retaining projection being held in the constriction by an enlargement at the end of the retaining projection.

For a better understanding of the invention and to show how it may be carried into effect reference will now be made, by way of example, to the accompanying drawing, in which: Figure 1 is a view of a button-operated switch from below; Figure 2 is a partially sectional side elevation of the button-operated switch of Figure 1, the contacts of which are closed; and Figure 3 is a partially sectional side elevation of the button-operated switch, the contacts of which are open.

In the Figures, there is denoted by 1 an electrically conducting housing of a buttonoperated switch, the said housing 1 comprising a lateral flange extension 2 lengthened on one side. The said flange extension 2 is formed with an aperture 3 through which a screw (not shown) can be passed, the housing 1 being secured, for example, to the chassis of an automobile vehicle or to the housing of a refrigerator by means of this screw connection. The flange extension 2 is joined to an elongate sleeve 4, in the interior of which an actuating element 5 consisting of plastics is so mounted as to be displaceable within a spring 6 which bears at one end against the sleeve 4 and at the other end presses against the actuating element 5.

Secured to that end of the actuating element 5 which is closer to the bottom end of the sleeve 4 is a contact member 7, which comprises a base portion 8 which has been pushed over chamfered faces 10 onto projecting lugs 9 on the actuating element 5 and is held in undercut portions of the actuating element 5. The base portion 8 is thereby fixedly connected to the actuating element 5.

In addition, the contact member 7 comprises a first spring arm 11 and a second spring arm 12, which are connected together by means of a resilient looped extension 13. The contact member 7 is integrally formed from a single piece of material, during its manufacture the base portion 8 first being bent over towards the second spring arm 12 whereafter the first spring arm 11 is bent towards the second spring arm 12 after the formation of the looped extension 13. The first spring arm 11 has, adjacent diametrically opposite sides of the actuating element 5, pointed contact projections 14 which are bent over perpendicularly to the plane of the first spnng arm 11 and press on the end of the sleeve 4 when the actuating element 5 is in the position of rest as illustrated in Figure 2, the contact member being stressed by virtue of the action of the bottom of the sleeve 4 on the pointed contact projections -14.

There is illustrated in Figure 3 the case where the actuating element 5 is depressed by, for example, the engine bonnet. The stress is removed from the contact member 7 and the second spring arm 12 bears against the base portion 8, while the first spring arm 11 is deflected upwards out of its Figure 2 position through an angle limited by a retain mg device. The retaining device here consists of a bent-over tie portion 15 which is situated at the free end of the first spring arm 11.

During manufacture of the contact member 7 the tie portion 15 is pushed through an opening 16 both in the base portion 8 and in the second spring arm 12, and is then bent over into a constriction 17 of the opening 16 in the second spring arm 12. The tie portion 15 has a widened portion 18 at its end so that the first spring arm 11 can be deflected only until the widened portion 18 abuts against the sides of the constriction 17.

When the bonnet is opened to release the actuating element 5, the spring 6 pushes the actuating element 5 upwards and hence the pointed projections 14 of the contact member 7 are urged against the bottom of the sleeve 4. Immediately after the pointed projections 14 make contact with this bottom surface the first spring arm 11 is moved downwards with the spring arm 12 until the spring arm 11 abuts the free end of the base portion 8 as shown in Figure 2. The contact assembly then moves out of the Figure 2 position by the first spring arm 11 pivoting about the free end of the base portion 8 until the first spring arm 11 bears entirely on the base portion 8 (this position not being shown). During this movement the pointed contact projections 14 wipe across the bottom surface of the sleeve 4, whereby impurities collected on the contact face are removed. In this way, a reliable contactmaking is ensured even if the joutton- operated switch has remained unused for some time. Thus, the illustrated and described switch is particularly suitable for use in an environment in which considerable impurities are present. For example, a button-operated switch situated in the engine compartment of an automobile vehicle is not only subjected to oxidation at its open contact, but deposits are produced thereon by the gases and vapours usually present in the engine compartment.

Moreover, such button-operated switches are generally seldom operated, so that when the engine bonnet is closed the impurities can become lodged without hindrance on the open contact faces.

An electrical connection from the contact member 7 to a succeeding electric circuit can be made, for example, by a flat socket being pushed onto the base portion 8 and onto the second spring arm 12.

WHAT WE CLAIM IS: 1. A button-operated electrical switch comprising a spring loaded actuating ele ment movably mounted in a housing and two contact members between which relative movement is produced to make or break an electrical path through the switch, when the spring loaded actuating element is moved on operation of the switch, wherein one of the contact members comprises a base portion by which it is mounted on said actuating element, and an arm which is resiliently coupled to the base portion and which can pivotally flex through only a limited angular range, and the contact members are arranged so that when the switch is in a closed condition said arm of the one contact member is urged resiliently against the other contact member, and wherein said housing is electrically conductive and is this other contact member.

2 A switch according to claim 1, wherein said one contact member is provided with connecting means for a wire or the like.

3. A switch according to any one of the preceding claims, wherein said arm and said base portion are parts of a single piece of material.

4. A switch according to any one of the preceding claims, wherein said one contact member is substantially in the form of a "J" in its unstressed condition, the base portion and said arm being included in the Iong and short limbs respectively of the "J" and the loop of the "J" being provided by a resilient

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. actuating element 5. Secured to that end of the actuating element 5 which is closer to the bottom end of the sleeve 4 is a contact member 7, which comprises a base portion 8 which has been pushed over chamfered faces 10 onto projecting lugs 9 on the actuating element 5 and is held in undercut portions of the actuating element 5. The base portion 8 is thereby fixedly connected to the actuating element 5. In addition, the contact member 7 comprises a first spring arm 11 and a second spring arm 12, which are connected together by means of a resilient looped extension 13. The contact member 7 is integrally formed from a single piece of material, during its manufacture the base portion 8 first being bent over towards the second spring arm 12 whereafter the first spring arm 11 is bent towards the second spring arm 12 after the formation of the looped extension 13. The first spring arm 11 has, adjacent diametrically opposite sides of the actuating element 5, pointed contact projections 14 which are bent over perpendicularly to the plane of the first spnng arm 11 and press on the end of the sleeve 4 when the actuating element 5 is in the position of rest as illustrated in Figure 2, the contact member being stressed by virtue of the action of the bottom of the sleeve 4 on the pointed contact projections -14. There is illustrated in Figure 3 the case where the actuating element 5 is depressed by, for example, the engine bonnet. The stress is removed from the contact member 7 and the second spring arm 12 bears against the base portion 8, while the first spring arm 11 is deflected upwards out of its Figure 2 position through an angle limited by a retain mg device. The retaining device here consists of a bent-over tie portion 15 which is situated at the free end of the first spring arm 11. During manufacture of the contact member 7 the tie portion 15 is pushed through an opening 16 both in the base portion 8 and in the second spring arm 12, and is then bent over into a constriction 17 of the opening 16 in the second spring arm 12. The tie portion 15 has a widened portion 18 at its end so that the first spring arm 11 can be deflected only until the widened portion 18 abuts against the sides of the constriction 17. When the bonnet is opened to release the actuating element 5, the spring 6 pushes the actuating element 5 upwards and hence the pointed projections 14 of the contact member 7 are urged against the bottom of the sleeve 4. Immediately after the pointed projections 14 make contact with this bottom surface the first spring arm 11 is moved downwards with the spring arm 12 until the spring arm 11 abuts the free end of the base portion 8 as shown in Figure 2. The contact assembly then moves out of the Figure 2 position by the first spring arm 11 pivoting about the free end of the base portion 8 until the first spring arm 11 bears entirely on the base portion 8 (this position not being shown). During this movement the pointed contact projections 14 wipe across the bottom surface of the sleeve 4, whereby impurities collected on the contact face are removed. In this way, a reliable contactmaking is ensured even if the joutton- operated switch has remained unused for some time. Thus, the illustrated and described switch is particularly suitable for use in an environment in which considerable impurities are present. For example, a button-operated switch situated in the engine compartment of an automobile vehicle is not only subjected to oxidation at its open contact, but deposits are produced thereon by the gases and vapours usually present in the engine compartment. Moreover, such button-operated switches are generally seldom operated, so that when the engine bonnet is closed the impurities can become lodged without hindrance on the open contact faces. An electrical connection from the contact member 7 to a succeeding electric circuit can be made, for example, by a flat socket being pushed onto the base portion 8 and onto the second spring arm 12. WHAT WE CLAIM IS:

1. A button-operated electrical switch comprising a spring loaded actuating ele ment movably mounted in a housing and two contact members between which relative movement is produced to make or break an electrical path through the switch, when the spring loaded actuating element is moved on operation of the switch, wherein one of the contact members comprises a base portion by which it is mounted on said actuating element, and an arm which is resiliently coupled to the base portion and which can pivotally flex through only a limited angular range, and the contact members are arranged so that when the switch is in a closed condition said arm of the one contact member is urged resiliently against the other contact member, and wherein said housing is electrically conductive and is this other contact member.

loop between said base portion and said arm.

5. A switch according to any one of the preceding claims, wherein the one contact member further comprises a further arm which interconnects the first-mentioned arm apd the base portion.

6. A switch according to any one of the preceding claims, wherein the firstmentioned arm of the one contact member comprises at least one contact projection for contacting the other contact member.

7. A switch according to claim 6, wherein the or each contact projection has been bent perpendicularly out of the plane of said first-mentioned arm.

8. A switch according to any one of the preceding claims, wherein one limit of said angular range is determined by retaining device.

9. A switch according to claim 9, wherein said retaining device comprises a retaining projection, from the first-mentioned arm, which abuts against a further portion of the one contact member to define said limit.

10. A switch according to claim 9, wherein said retaining projection is at an end of said first-mentioned arm and projects through an opening having a construction, the end of the retaining projection being enlarged so that said limit is defined by the retaining projection being prevented from further movement by cooperation of said constriction and the enlargement of the retaining projection.

11. An electrical switch substantially as hereinbefore described with reference to Figures 1,2 and 3 of the accompanying drawings.