US3303306A

US3303306A - Membrane switch with first and second independently movable portions

Info

Publication number: US3303306A
Application number: US385186A
Authority: US
Inventors: Fischer Max; Brink Gerhard
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1963-07-25
Filing date: 1964-07-27
Publication date: 1967-02-07
Anticipated expiration: 1984-02-07
Also published as: GB1033475A; DE1214302B; AT240955B; CH425953A; BE650861A; NL6408494A

Description

Feb. 7, 1967 M FISCHER ETAL 3,303,306

MEMBRANE SWITCH WITH FIRST AND SECOND INDEPENDENTLY MOVABLE PORTIONS Filed July 27, 1964 INVENTORS "l a. T72 J1 11L 6 I United States Patent 3 303 306 MEMBRANE SWETCH WITH FIRST AND SECOND INDEPENDENTLY MOVAELE PORTEGNS Max Fischer, Goppiugen, and Gerhard Brink, Zutfenhausen, Germany, assignors to Robert Bosch G.rn.h.H., Stuttgart, Germany Filed July 27, 1964, Ser. No. 385,186 Claims priority, application Germany, Juiy 25, 1963, B 72,838 18 Claims. (Cl. zen-s3 The present invention relates to a membrane switch, and more particularly to a membrane switch responsive to different pressures of a controlling fluid to operate different contact means.

Electrical membrane switches are known, and in accordance with prior art constructions, the displacement of a membrane by the pressure of the fluid is transmitted by linkage means to two or more contact means for actuating the same. The constructions of the prior art are complicated, include very delicate parts, and are expensive to manufacture, particularly since the assembly and mounting of the many parts in the housing of the pressure responsive switch causes great difficulties and is time consuming.

It is one object of the present invention to overcome the disadvantages of membrane switches according to the prior art, and to provide a membrane switch of simple construction in which a plurality of electrical contact means are operated by the varying pressure of a controlling fluid acting on the membrane.

Another object of the invention is to provide a membrane switch with independently movable membrane portions which individually control correlated contact means.

Another object of the invention is to provide a membrane switch in which each individually movable membrane portion is directly connected by rigid actuating means to a correlated electrical contact means, so that the linkages of the prior art are avoided.

Another object of the invention is to provide a membrane switch with a membrane having a plurality of individually movable membrane portions which are biased to respond to different actuating pressures of a controlling fluid acting on the membrane so that contact means are successively actuated.

Another object of the invention is to differently bias the electrical contact means of a membrane switch, and to connect each contact means to an independently movable portion or" a membrane so that different fluid pressures cause selective actuation of the contact means.

With these objects in view, the present invention relates to a membrane switch which comprises a membrane mounted on a support and including a plurality of independently movable membrane portions which are, respectively, connected to a plurality of contact means for actuating the same when the respective membrane portion is displaced. A plurality of biasing means is provided for applying different forces to one side of the membrane portions, preferably through actuating means connecting a contact means with the membrane portions, so that fluid pressure applied to the membrane portions will cause actuation of the contact means whose correlated membrane portions are displaced at different pressures by the pres sure fluid.

One embodiment of the invention comprises a support, such as a housing which is divided by the membrane into a chamber for the fluid, and another chamber in which the contact means are mounted. Each contact means includes an actuating member on which a biasing means, preferably in the form of an adjustable spring acts. The actuating member is connected by actuating means to a corresponding membrane portion of the membrane,

3,303,306 Patented Feb. 7, 1967 and such actuating means include rigid members secured to the respective membrane portion.

In one embodiment of the invention, two membrane portions are separated by a fold in the membrane to be individually displaceable by the fluid pressure, and a segment-shaped plate is secured to each membrane portion. In another embodiment of the invention, a circular fold in the membrane separates a circular membrane portion from an outer annular membrane portion, and one actuating means which is connected to one contact means includes a plate secured to the inner portion, while the other actuating means cooperating with the other contact means, includes a bell-shaped member whose rim is secured to the annular membrane portion.

In all embodiments of the invention the actuating members of the several contact means are directly connected to individually movable membrane portions, so that no linkages are required.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is a longitudinal axial section illustrating one embodiment of the invention;

FIG. 2 is a cross sectional view taken on line II-II in FIG. 1; and

FIG. 3 is a side elevation, partly in axial section, illusstrating another embodiment of the invention.

Referring now to the drawings, and more particularly to FIGS. 1 and 2, the housing of the membrane switch is composed of a generally pot-shaped housing part 1 consisting of an insulating material, and being closed by a cover means having a crimped edge secured to a flange of housing part 1. Between cover 2 and housing part 1, the peripheral edge portion 3 of a membrane 4 is clamped so that the interior of the housing is divided into a chamber 7 and into a chamber 8. Chamber 7 has a tubular inlet means 5 secured to cover 2 and provided with a throttle opening 6. Pressure fluid can be supplied through inlet means 5 into chamber 7, and will act on one side of membrane 4 to displace the same toward chamber 8. A straight fold 17 is provided in membrane 4, dividing the same into two substantially segment-shaped membrane portions which are individually movable due to the provision of fold 17. For example, when one of the segment-shaped membrane portions is prevented from movement, the pressure of the pressure fluid in chamber 7 will still be able to displace the other membrane portion.

Two contact means, constructed as snap-over switches, are disposed in chamber 8. Each contact means has a frame-shaped arm 9, carrying a contact piece 10, and adapted to move between two positions including a circuit closing position in which contact piece 10 abuts another contact piece, not shown, on housing part 1. An actuating tongue member 11 projects into the cutout of contact arm 9 and is connected by a spring 12 to the opposite part of contact arm 9.

Housing part 1 has two projections, in which springs 13 are mounted which respectively abut the ends of actuating tongue members 11 to bias the same to move toward membrane 4-. Adjusting screws 14 are mounted in threaded parts of the projections on housing part 1, and are individually adjustable for adjusting the spring tension of biasing springs 13.

Springs 13 are diiferently adjusted to produce diiferent forces on actuating member 11, and such forces are transmitted to the membrane portions by actuating means 18 and 19 whose upper ends support actuating members 11 at the points at which springs 13 act. Actuating means 18 and 19 include

plates

15 and 16 which are segmentshaped, as best seen in FIG. 2, and which are respectively secured to the two membrane portions and separated by fol-d 17 in membrane 4. The straight edges 15 and 16' of the

segmentashaped plates

15 and 16 are disposed directly adjacent the flexible fold 17. As a result, it is possible to move the

plates

15 and 16 independently of each other together with the corresponding membrane portions.

While

plates

15 and 16 are located in chamber 8 on one side of membrane 4, other plates 4a are secured to the other side of membrane 4 and cooperate with inwardly raised beads in cover plate 2 which are engaged by plates 4a when the pressure of .springs 13 urges the membrane downward, as viewed in FIG. 1.

When pressure fluid is admitted through throttle 6 and inlet means in chamber 7, the same pressure acts on the two membrane portions and is transmitted through the actuating means 15, t8 and 16, 19 to the actuating members 11 of the contact means 9. Assuming that spring 13 on the left side of FIG. 1 is adjusted to produce a lesser force than the other spring 13, increase of. the pressure of the. pressure fluid in chamber 7 will first displace the membrane portion on the left side, as viewed in the drawing, so that the corresponding actuating. member will be moved upward, and cause the corresponding contact means to assume a circuit closing position. contact means 9 is not yet actuated, since the respective pressure of the pressurefluid is insufficient to overcome the greater force produced by the differently adjusted spring 13 on the right side of the FIG. 1. However, after the pressure of the pressure fluid in chamber 7 has been increased to be sufficient to overcome the force of the spring 13 on the right side of FIG. 1, the corresponding contact means is actuated.

The independent actuation of the contact means by the pressure fiuid is possible due to the fact that the two portions of membrane 4 which are separated by fold 17, are independently movable so that displacement of the left membrane portion will not cause displacement of the right membrane portion which is, at first, held back by the greater force of the corresponding spring 13.

While in the above described construction of FIGS. 1 and 2, the increasing pressure causes actuation of the contact means to close a circuit, it is evident that the construction can be reversed, so that increased pressure will cause breaking of a circuit.

The embodiment illustrated in FIG. 3 corresponds substantially to the embodiment described with reference to FIGS. 1 and 2, and corresponding parts are indicated by like reference numerals. Instead of two segment-shaped movable membrane portions, and two corresponding segment-

shaped plates

15 and 16, the embodiment of FIG. 3 provides an inner central substantially circular membrane portion separated bya circular inwardly convex told 22 from an outer annular membrane portion.

The actuating means for the contact means 9 on the left side of FIG. 3 include a circular plate 21 secured to the central portion of the, membrane, and having a perpendicu larly projecting arm 24 connected to the actuating member 11 of the respective contact means 9. The actuating means for the contact means on the right side of FIG. 3, include a bell-shaped member 2t) whose lower rim is secured to the annular membrane portion outside of fold 22, and whose top has an opening 24 through which projecting arm 23 of member 21 passes.

The central portion of the ,top of bell-shaped member 21 has a guide portion 26 with a guide bore through which a guide pin 25 secured to the plate member 21 passes.' The free end of guide pin 25 is lguided in a guide means 27 provided on housing part 1. Bell-shaped member 20 has a projection 29 on its top connected to actuating member 11 so that the pressure of spring 13 on The other V 4'. the right side of FIG. 3 is transmitted to the bell-shaped member 2% and from there to the outer annular membrane portion. Guide members 25, 2d and 27', which are parallel to projection 29 and projecting arm 23, assure a parallel movement of members 20 and 21, and the centering of member 20 relative to member 21. In the embodiment of PEG. 3 a lesser pressure of the fluid in chamber 7 will be sufiicient to displace the annular membrane portion and to shift actuating means 20, 26 so that contact means 9 on the right side of FIG. 3 is first actuated. When the pressure of the fluid is increased, it is sufficient to displace the central membrane portion with member 21 so that contact means 9 on the left side is actuated.

While the disclosed embodiments provide only two contact means and corresponding movable membrane portions, a greater number of contact means and independently movable membrane portions can be provided.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of membrane switches differing from the types described above.

While the invention has been illustrated and described as embodied in a membrane switch in which two independently movable membrane portions respond to different pressures to individually actuate two contact means, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any Way from the spirit of the present invention. V

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of, this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is: t

1. A membrane switch comprising, in combination, a support; membrane means mounted on said support and including a first movable membrane portion, a second movable membrane portion, and means intermediate said first and second movable membrane portions and including a poition of said membrane means and permitting said movable membrane portions to move substantially independently of each other; a plurality of contact means mounted on said support, each contact means including an actuating member movable between two positions; biasing means on said support for holding said members in one of said positions, said biasing means acting on said actuating members with different forces; a plurality of actuating means connecting said membrane portions with said actuating members, respectively, so that different forces are transmitted to said membrane portions and movement of each membrane portion causes movement of the correlated actuating member to the other position thereof; and means for applying a fluid to said membrane portions so that said actuating'mem bers are individually operated by saidmembrane portions moved by the fluid when the increasing pressure of the fluid successively overcomes said different forces.

2. A membrane switch according to claim 1, said actuating means including plates respectively secured to said membrane portions. 7

3. A membrane switch according to claim 1, said actuating means connecting one side of said membrane portions with said actuating members, respectively, said fluid being applied to the other side of said membrane portions.

4. A membrane switch comprising, in combination, a support; membrane means mounted on said support and including a fold and a plurality of independently movable membrane portions separated by'said fold; a plurality of contact means mounted on said support, each contact means including an actuating member movable between two positions; biasing means on said support for holding said members in one of said positions, said biasing means acting on said actuating members with different forces; a plurality of actuating means connecting said membrane portions with said actuating members, respectively, so that different forces are transmitted to said membrane portions and movement of each membrane portion causes movement of the correlated actuating member to the other position thereof; and means for applying a fluid to said membrane portions so that said actuating members are individually operated by said membrane portions moved b the fluid when the increasing pressure of the fluid successively overcomes said different forces.

5. A membrane switch according to claim 3, said support comprising a housing, said membrane means mounted on said housing and dividing said housing into two chambers, said contact means mounted on said housing in one of said chambers, and said means for applying a fluid to the other side of said membrane portions connected to the other of said chambers.

6. A membrane switch comprising, in combination a housing; membrane means mounted on said housing and including a fold means and a plurality of independently movable membrane portions separated by said fold means, said membrane means dividing said housing into two chambers; a plurality of contact means mounted on said housing in one of said chambers, each contact means including an actuating member movable between two positions; biasing means on said housing for holding said members in one of said positions, said biasing means acting on said actuating members with different forces; a plurality of actuating means connecting one side of said membrane portions with said actuating members and including plates respectively secured to said membrane portions so that different forces are transmitted to said membrane portions and movement of each membrane portion causes movement of the correlated actuating member to the other position thereof; and means connected to the other of said chambers for applying a fluid to the other side of said membrane portions so that said actuating members are individually operated by said membrane portions moved by the fluid when the increasing pressure of the fluid successively overcomes said different forces.

7. A membrane switch comprising, in combination, a support; membrane means mounted on said support and including straight fold means and two independently movable membrane portions separated by said fold means; a plurality of contact means mounted on said support, each contact means including an actuating member movable between two positions; biasing means on said support for holding said members in one of said positions, said biasing means acting on said actuating members with different forces; a plurality of actuating means connecting one side of said membrane portions with said actuating members, respectively, so that different forces are transmitted to said membrane portions and movement of each membrane portion causes movement of the correlated actuating member to the other position thereof, said actuating means including segment-shaped plates respectively secured to said membrane portions, said segment-shaped plates having straight edges located on opposite sides of, and adjacent said straight fold of said membrane means; and means for applying a fluid to the other side of said membrane portions so that said actuating members are individually operated by said membrane portions moved by the fluid when the increasing pressure of the fluid successively overcomes said different forces.

8. A membrane switch comprising, in combination, a support; membrane means mounted on said support and including a circular fold, an inner movable membrane portion surrounded by said fold, and an outer annular membrane portion surrounding said fold so that said membrane portions are movable independently of each other; a plurality of contact means mounted on said support,

each contact means including an actuating member movable between two positions; biasing means on said support for holding said members in one of said positions, said biasing means acting on said actuating members with different forces; a plurality of actuating means connecting one side of said membrane portions with said actuating members, respectively, so that different forces are transmitted to said membrane portions and movement of each membrane portion causes movement of the correlated actuating member to the other position thereof, one of said actuating means including a circular member secured to said inner membrane portion, and another actuating means including an annular member secured to said outer annular membrane portion; and means for applying a fluid to the other side of said membrane portions so that said actuating members are individually operated by said membrane portions moved by the fluid when the increasing pressure of the fluid successively overcomes said different forces.

9. A membrane switch comprising, in combination, a housing; membrane means mounted on said housing and including straight fold and two independently movable membrane portions separated by said fold, said membrane means dividing said housing into two chambers; a plurality of contact means mounted on said housing in one of said chambers, each contact means including an actuating member movable between two positions; biasing means on said housing for holding said members in one of said positions, said biasing means acting on said actuating members with different forces; a plurality of actuating means connecting one side of said membrane portions with said actuating members, respectively, so that different forces are transmitted to said membrane portions and movement of each membrane portion causes movement of the correlated actuating member to the other position thereof, said actuating means including segmentshaped plates respectively secured to said membrane portions, said segment-shaped plates having straight edges located on opposite sides of, and adjacent said straight fold of said membrane means; and means connected to the other of said chambers for applying a fluid to the other side of said membrane portions so that said actuating members are individually operated by said membrane portions moved by the fluid when the increasing pressure of the fluid successively overcomes said different forces.

iii. A membrane switch comprising, in combination, a housing; membrane means mounted on said housing and including a circular fold, an inner movable membrane portion surrounded by said fold, and an outer annular membrane portion surrounding said fold so that said membrane portions are movable independently of each other, said membrane means dividing said housing into two chambers; a plurality of contact means mounted on said housing in one of said chambers, each contact means including an actuating member movable between two positions; biasing means on said housing for holding said members in one of said positions, said biasing means acting on said actuating members with diflerent forces; a plurality of actuating means connecting one side of said membrane portions with said actuating members, respectively, so that different forces are transmitted to said membrane portions and movement of each membrane portion causes movement of the correlated actuating member to the other position thereof, one of said actuating means including a circular member secured to said inner membrane portion, and another actuating means including an annular member secured to said outer annular membrane portion; and means connected to the other of said chambers for applying a fiuid to the other side of said membrane portions so that said actuating members are individually operated by said membrane portions moved by the fluid when the increasing pressure of the fluid successively overcomes said different forces.

11. A membrane switch comprising, in combination, a M

housing; a membrane means mounted in said housing and including an inner membrane portion and an outer annular membrane portion surrounding said inner membrane portion, said membrane means including an additional portion intermediate said inner and outer membrane portions, said additional portion being constructed and arranged to permit movement of said inner and outer membrane portions independently of each other, said membrane means forming in said housing at one side thereof a chamber for a fluid adapted to act on said membrane means; two contact means mounted on said housing on the other side of said membrane means, each contact means including an actuating member movable between two positions; biasing means on said support for holding said actuating members in one of said positions, respectively, said biasing means acting on said actuating members with different forces; a first actuating means including a bellshaped member having an annular rim secured to said annular membrane portion at said other side of said membrane means, and a projection connected with one of said actuating members, said bell-shaped member having an opening spaced from said projection; a second actuating means including a plate secured to said inner membrane portion and a projecting arm passing through said opening in said bell-shaped member and connected with the other of said actuating members so that said biasing means transmit diiferent forces through said actuating means and members to said membrane portions and movement of each membrane portion causes movement of the correlated actuating member to the other position thereof; and inlet means on said housing communicating with'said chamber and adapted to supply fluid to the same so that the fluid acts on said membrane portions whereby said contact members are individually operated by said membrane portion moved by the fluid when the increasing pressure of the fluid successively overcomes said different forces. i

12. A membrane switch as set forth in claim 11 wherein said plate of said second actuating means is substantially circular, and wherein said projecting arm projects from the periphery of said plate perpendiculariy thereto; and wherein said projection projects perpendicularly from the top portion of saidbell-shaped member of said first actuating means, and parallel to said projecting arm.

13. A membrane switch as set forth in claim 11 and including a guide pin projecting from the center of said plate of said first actuating means transverse to said membrane means for movement with said inner membrane portion; and wherein said bell-shaped member of said first actuating means has a central guide bore slidably surrounding said guide pin.

14. A membrane switch as set forth in claim 13 and including guide means on said housing for guiding the free end of said guide pin.

15. A membrane switch as set forth in claim 11 wherein said plate of said second actuating means has a projecting portion disposed to abut the inner suface of the top of said bell-shaped member when said inner membrane portion is displaced by the pressure of the fluid whereby movement of said inner membrane portion, of said projecting arm, and of the corresponding actuating member is limited.

16. A membrane switch as set forth in claim 15 wherein said plate is circular, and wherein said projecting arm and said projecting portion project from the periphery of said plate perpendicularly to the same and are located diametrically opposite each other; and including a guide pin projecting from the center of said plate'perpendicularly to the same, said bell-shaped member having in the top thereof a guide bore for the passage of said guide pin; and guide means on said housing for guiding the free end of said guide pin. 17. A membrane switch as set forth in claim 11 wherein said intermediate additional portion of said membrane means is a circular fold convex toward the other side of said membrane means.

18. A membrane switch comprising, in combination, a

support; membrane means mounted on said support and including a first movable membrane portion, a second movable membrane portion, :and means intermediate said first and second movable membrane portions and includ ing a portion of said membrane means and permitting said movable membrane portions to move substantially independently of each other; a plurality of contact means mounted on said support; a plurality of actuating means connecting said contact means with said movable membrane portions, respectively, so that movement of the latter causes actuation of said contact means, respectively; a plurality of biasing means for applying different forces to one side or" said membrane portions; and means for applying fluid pressure to the other side of said membrane portions so that said contact means are individually actuated when different fluid pressures act on and displace said membrane portions. 1

References titted by the Examiner,

UNITED STATES PATENTS 2,975,251 3/1961 Belleretal 20o-s1x 3,064,094 11/1962 Marchi ZOO-83' 3,187,136 6/1965 C0rdcret.ai, 2QO81X BERNARD A. GILHEANY, Primary Examiner.

H. FLECK, Assistant Examiner.

Claims

18. A MEMBRANCE SWITCH COMPRISING, A SUPPORT; MEMBRANCE MEANS MOUNTED ON SAID SUPPORT AND INCLUDING A FIRST MOVABLE MEMBRANCE PORTION, A SECOND MOVABLE MEMBRANCE PORTION, AND MEANS INTERMEDIATE SAID FIRST AND SECOND MOVABLE MEMBRANE PORTIONS AND INCLUDING A PORTION OF SAID MEMBRANE MEANS AND PERMITTING SAID MOVABLE MEMBRANE PORTIONS TO MOVE SUBSTANTIALLY INDEPENDENTLY OF EACH OTHER; A PLURALITY OF CONTACT MEANS MOUNTED ON SAID SUPPORT; A PLURALITY OF ACTUATING MEANS CONNECTING SAID CONTACT MEANS WITH SAID MOVABLE MEM-