DE2245376A1 - NORMALLY OPEN PRESSURE DEPENDENT SWITCH - Google Patents

Description

Received at AS AA MM

DR. MÜLLER-BORE DIPL-PHYS. DR. MANITZ DIPL-CHEM. DR. DEUFEL

DIPL.-ING. FINSTERWALD DIPL-INQ. .Q RAM XOW

PATENT LAWYERS

22 4-5 576.5 Hünchen, the J & MV. IW

M / th - G 2265

GENERAL MOTOES COHPOEiI ¹ ION Detroit, Michigan, USA

Normally open pressure dependent switch

The present invention "relates generally to normally open pressure sensitive or pressure sensitive switches that close when exposed to pressure exceeding a predetermined value. In particular, the invention relates to a normally open pressure-dependent switch with a first and a second member made of a flexible dielectric material, which in the are substantially plane-parallel, an electrically conductive, first contact member which is on a surface of the first member is stacked, and with an electrically conductive, second contact member which is on a surface of the second contact member is stacked, wherein the first and the second contact member through an elastic having openings Spacers are kept at a distance ".

309814/0789

Dr. Müller-Bor * "Dr. Manltz · Dr. Deufel · Dipl.-Ing.Finsterwald Dipl.-Ing.Gramkow Braunschweig, Am Bärgerpark 8 β Munich 22, Robert-Koch-StraBe 1 j Stuttgart-Bad Cannstatt, MarktstraB 3 Telephone (0531) 73887 Telephone (0811) 293645, Telex 5-22050 mbpat ^Telephone C ⁷¹¹ ) »« 81

. Bank: Central Cash Office Bayer. Volktb «nken, Munich, account number se22 Post check: Munich 95495

_ 2 -

From US-PS 3 5 ^ 1 3 ^ 3 (Butler) are normally open Pressure-dependent switches known that close when exposed to a pressure above a predetermined value are. For one application, the switch of this type is within the seat cushion of a vehicle seat next to it Seat surface arranged and connected to a suitable electrical circuit, the switch closes when a vehicle occupant assumes a seated position and the circuit gives an indication that the seat is in a occupied state. In general, these switches have first and second members, essentially are plane-parallel and consist of a generally flexible dielectric material and a first and a have second contact, which are electrically conductive and generally plane-parallel and on their opposite surfaces are piled up. The planar-parallel links are correct consist of a suitable plastic, such as. B. a polyester, while the contacts are usually made of copper. A multitude of elastic foam strips arranged laterally at a distance from one another or an elastic, perforated one Foam pads are arranged between the plane-parallel links so that when they are not compressed, keep the contacts at a distance from each other. As soon as the plane-parallel members have a pressure above a predetermined pressure The foam strip or will be subjected to pressure substantially perpendicular to their respective planes the foam pad is compressed so that the contacts can be connected and the switch contacts can be closed. To compress the foam without a contact connection to avoid it is from the above-mentioned US-PS 3 5 ^ 1 known to add a protruding '!' to the contacts, which are received within the cavities or openings which are delimited or formed by the foam. There

309814/0789

BATH ORIGINAL

these projecting parts by the plane-parallel links are not supported, they can plastically deform under the bridges to which the switches are exposed, when used on vehicle seats.

To solve this problem, a normally open pressure-dependent switch is created according to the invention, which is characterized in that a plurality of projections or round projections are provided on the first and second contact member, many by pressing or compression molding of depressions in the plane-parallel bsw . flat members and their respective contact members, the first and second planar members being oppositely spaced from one another in such a manner that the projections on the first and second contact members face one another and are spaced from one another by the resilient spacer w ith having openings for receiving the projections on the contact members, the spacer being compressible to allow the opposing projections on the first and second contact members to engage and thus to close the switch when the planar members have a pressure above a predetermined pressure perpendicular to their opposite surfaces. Such druckebiiängigei 'switch has a relatively simple and flexible construction, and increased contact areas _t withstand the plastic deformation when the switch is used or "is in the working state.

30981-4 / 0789

Each contact member preferably has a flat fork-like shape shape, whereby-the prongs of the fork from one another ■ 'separated and the protrusions along' the prongs of the fork are shaped. This results in an extraordinary fimcttH len switch and leads to a minimum in discomfort a passenger seated on a seat, in which the container installed. More flexibility can be achieved by placing the parts of the contact members * between each pair of projections along a prong is made narrower than the protrusions

When using the pressure-dependent container according to the invention as a bit switch in a vehicle seat Perception of the occupation of the seat in which the Container next to the Bitz surface of the seat and arranged essentially parallel to this ßitzoberflache is, it is advantageous to have the layer * or leaf member closest to the seat surface with one to equip larger surface area than the area of the elastic spacer and the other ßchicht- or leaf member to thus the switch against electrical To protect against damage, fall a liquid spilled on the ßitzfläche next to the switch will.

In the preferred embodiment of the invention the planar members consist of a polyester material and generally have a paddle or spade shape, wherein they are arranged opposite to each other while the contact members generally have a fork shape and their prong parts in opposite relationship to one another stacked on the blade or blade parts of the Planarglietfer and their handle parts on the handle areas of the planar members in laterally spaced from one another

109114/0719

■ existing relationship to each other are stacked. First and second terminals for connecting the switch to an electrical circuit correspondingly connected to the handle parts of the contact member, their lateral distance from each other a connection of the terminals and thus the closing of the switch prevents. An elastic one Foam pad is arranged between the blade or spade parts of the planar members and with the vane portions of the planar members by an adhesive in a generally interlayer construction firmly connected. The foam pad has a plurality of openings, the opposite ends of which mouth in opposite sets of corresponding prong parts of the contact members. The openings can be oblong be and extend according to the length of the tine parts or made shorter to a plurality of separate to obtain openings along each set of opposing tine parts. A number of frustoconical projections is by indentations in the blade or blade sections of the planar members and the corresponding prong parts of the contact members formed so that the depressions of the planar members the depressions of the contact members. The protrusions are received in the openings of the foam padding normally the opposite apexes of the corresponding projections of the contact members at a distance from one another holds so that the switch is open. The foam pad is compressed when the planar limbs are subjected to a pressure above a predetermined pressure perpendicular to their planar surfaces To enable crests of the projections to come into engagement with one another and thus close the switch. By

JG98U / Q789

the lateral distances between the prong parts of each contact member is reduced the rigidity that the Switch is imparted by the haterial of the contact members, with also the possibility that the switch is on Causes discomfort for the seated vehicle occupant, if the switch is used to determine an occupancy of a seat, is avoided. Between the protrusions if the prong parts have strip parts whose width or width is smaller than the diameter of the projection so as to further reduce the rigidity of the switch.

According to the invention an improved, normally open pressure dependent switch is provided which has a first and a second substantially planar member made of a flexible dielectric material, which are arranged at a distance from one another, wherein electrical conductive, generally planar first and second contact members on respective opposing ones Stacked over surfaces of the first and second planar members and a number of embossed protrusions in the Planar members and is formed in their respective contact members, bo that the projections are taken in openings which are bounded or formed by an elastic material, which is normally the apex the projections of the contact members in, distance from each other holds. The elastic material can be in the form of a perforated foam pad, its opposite sides firmly adhering the planar members at a distance from one another, with its openings the Record embossed depressions of the planar members and the contact members. The embossed protrusions of the planar links and the contact members preferably have one

309814/0709

im £ jlgB.ffi # iii # n cone £ rtaifip; f-like iöfffö * Werbei the limb spacings in their 'e & tsprieJiemiefi even the projection, ea büden _t b.ü that- the stiffness b) 2w «ility of the © switch through the -Contact links not noticeably increased wiFä «Me PlänörgÜeder have wrongly © ine Schaufel *! or ßjtstenförffi _t whereby they are opposite to each other and the contact members have a fork-like shape, while the tine parts of the contact members are laminated and embossed on the blade portions of the planar members to form the projections, while the distances a \ fish the tine parts of each contact member lead to lowering the rigidity of the switch and the handle parts of the contact members are stacked on the handle parts of the planar members. The blade portion of one of the planar members is preferably larger than the blade portion of the other planar member so that the larger blade portion can be located on top of the switch when the switch is in a vehicle for perception the occupancy of the seat, whereby the switch is also shielded against electrical damage that can be caused by liquids accidentally spilled on the seat. In the preferred embodiment of the invention, the handle portions of the contact members have respective terminals connected to them and laterally spaced from one another to prevent the terminals from engaging and thus closing the switch. In addition, the embossed projections along the prong parts of the contact members are electrically connected by strip parts, the width or width of which is smaller

909814/0799

than the diameter of the projections is around the stiffness that is imparted to the switch by the contact members is awarded to further decrease.

The appended claims determine the scope of the claimed invention. The invention and the manner in which it can be carried out are set out below with reference to the attached Drawings described in more detail! show in it:

Fig. 1 is a partially broken away perspective view of a vehicle seat, the seat cushion a normally open pressure sensitive switch according to the present invention which is closed when a vehicle occupant takes a seated position!

FIG. 2 is an enlarged plan view of the switch j shown in FIG

Fig. 3 is an enlarged sectional view not along the line Line 3-3 of FIG. 2 to illustrate the interlayer construction of the switch, which has an upper and a lower planar member which are spaced from one another and on their opposite sides Planar contact members corresponding to surfaces are stacked, a foam pad, its openings to the contact members open or open there, and embossed frustoconical projections in the planar members

309814/0711

224531S

and in their respective contact members, those in the opposite ends of the openings are taken up and kept at a distance from each other by the cushion} '

Figure 4 is an enlarged generally sectional view along the line 4-4 of FIG. 2 to illustrate a connection terminal of the switch j

5 is an enlarged disassembled perspective view of the switch for illustrative purposes the foam pad, the fork-like shape of the contact members and the relative position the contact members on the blade-like or spade-like planar members; and

6 is a perspective view of a foam pad, whose openings have a smaller size than those of the foam pad according to Fig. ^ to have.

Referring to the terms and particularly to FIG. 1, this figure shows that the vehicle floor 10 supports a vehicle seat, which is indicated generally by the reference numeral, and that a conventional manner _r by a not shown supporting structure. The seat cushion 14 of the seat 12 supports a normally open pressure sensitive switch 16 according to the present invention which is located generally adjacent the seat surface. As described in more detail below, the switch 16 closes when a vehicle occupant assumes a seated position, the switch being connected to a suitable electrical circuit which is occupied

3098U / 0789

224537 ©

Indicates the state of the seat or a desired function controls in this context.

Referring now to Figures 2, 3 and 5, these show Figures the switch 16 with an upper and lower one generally planar limb 18b £ w, 20 which from a suitable planar material of a generally flexible electrically insulating material such as z. B. a polyester material, are made to a thickness of approximately 0.010 cm. The upper planar limb 18 has a leaf-shaped part 22, the size of which is slightly smaller than that of the leaf part 24 of the lower Planar member 20 is so that the switch is protected against electrical short circuits that take place can if a liquid is accidentally poured out onto the seat cushion 14 of the seat 12. Appropriate Handle parts 26 and 28 of the planar members 18 and extend from the blade parts 22 and 24 and have in the essentially the same width or width. As best seen in Figure 5, are generally associated with the Reference numerals 30 and 32 denote fork-like Contact members are stacked accordingly on the planar members 18 and 20 and made of a copper foil Thickness of approximately 0.0038 cm. The contact links 30 and 32 each have a corresponding number Fork parts 34 and 36, which extend along the Extend the length of the corresponding paddle parts 22 and 24, respectively. The contacts 30 and / or. 32 also have corresponding Handle parts 38 and 40, which are calibrated extend along the handle portions 26 and 28, respectively, of the planar members. An embossing process can be used to attach the contact members to the planar members stack up. To perform this operation, will

309 * 14/0789

a copper foil, which is slightly larger in its area than the contact member, on the plahar member hung up. A heated tool or a heated one Stamp with a cutting edge, \ <ielclie den Defined outline of the contact member is then placed on the copper foil. The abxtfärtsbextfigung des With the stamp, the contact section of the film is separated from the adjacent excess material, with the heat of the tool adheres both the contact member and the excess material to the planar member connects. The excess material is then stripped from the planar member, whereupon the planar member and the contact member can be heated as described below to ensure a secure bond between the planar member and to maintain the contact member within the outline of the contact member.

A generally rectangular pad, as generally indicated by reference numeral 42 in Figure 5, is arranged between the paddle parts 22 and 24 and composed of a suitable elastic material, such as B. a polyurethane foam with open cells. One glue or binder is on the opposite Sides of the pad 42 applied and against unwanted adhesion prior to assembly a suitable protective layer, not shown, is protected. The protective layer is removed from the pad 42 to expose the binder or adhesive that is after the installation of the switch, the paddle parts 22 or 24 with the pad 42 in a generally intermediate layer construction attached to each other. The built-in switch has a number of elongated ones openings 44 in the pad 42 in the longitudinal direction

109814/0719

corresponding to opposite sets of prong parts or J6 of contact members 30 and 32, respectively, these openings also open towards these chunks or open there. It is also possible to use a similar foam pad, as shown generally by reference numeral 46 in FIG. 6, along with a plurality of separate ones Use openings 48 that are to the opposite sets of prong parts 3 ^ and 36, respectively, of the contact members to open.

The planar members 18 and 20 with the outlines of the contact members 30 and 32, respectively, by the punch and by the The same are embossed on the embossing process to a temperature between 149 and 177 degrees Celcius before the Installation of the switch heated. With this heating, the contact members with the planar members become inside firmly adhered to the outline of the contact member. While the planar members and contact members are being heated at this temperature, an appropriate tool is used or a corresponding B stamp for embossing the paddle parts 22 or 24 and the corresponding tine parts 34 and 36 of the contact members used to make the frustoconical To form projections 50 and 52, the best from Figs. 3 and 5 aind can be seen. The Stamp remains in engagement with the planar members while the planar members cool to ambient temperature to prevent the protrusions from becoming planar or jump back to the flat configuration. Once the switch is installed, the openings 44 take place in the upholstery 42, the projections 50 and 52, as best shown in Fig. can be seen, with pad 42 normally spacing the apices of the projections apart. As soon the paddle parts 22 and 24 of the planar members have a pressure above a predetermined value perpendicular to their

JQ98U / Q7IS

arcs a; .- "/ 22453? $ -

exposed to flat surfaces, such as a. Β » when a]? vehicle occupant has a seated position on the Seat i2 occupies ,, the, cushion 42 is compressed ,,. to allow the apices of the projections 50 or 52 come into engagement with each other and thus the Switch is closed. During this procedure the recessed portions of the planar members support the recessed portions of the contact members to help prevent any plastic deformation of the contact members takes place.

The interconnected contact members form a conductive path through their respective handle portions 38 and 40, respectively, between a pair of terminals 54 and 56, see Figs. 2 and 5 * These connection terminals enable a pair of supply lines 58 and 60 as well as the switch within the electrical line to be connected. 4 shows an enlarged sectional view of the terminal 54 with a connecting member 62 which supports the lead 58 through a section 64 and electrically connects it through a part 66. The connecting member has a flattened part 68 with an opening 70 which is aligned with the openings 72 and 4 in the handle parts 26 and 38 of the planar member 18 and the contact member 30. A metal insert 76 extends through the aligned openings and has an upper support lip 78 which is connected to the top of a handle part 26 in a suitable manner and is covered with a polyester cover 80, see also E ¹ Ig. 2, in order to avoid electrical contact of the insert 76 with a conductive seat part. The lower side of the insert 76 has a lip 82 which holds the part 68 of the connecting member 62 in engagement with the handle part 38 of the contact member 30. The connector

309814/0719

¹ is similar to terminal 54, "α that 'ei, e is not ben, only that it must be said that the adapter parts 38 and 40 of the contact members 30 to 32 et are offset so that the terminals come into contact with one another" ! and not even if there is no foam spacer pad or the like between the handle parts of the planar links **

Within the corresponding levels of the contact members, the distances between the prong parts 34 and 36 the stiffness created by the contact elements of the switch is awarded, as well as the possibility that. a labe- ' hagen caused the seated vehicle occupant on the seat will. White between jumps 50 and $ 2 strip parts 84 corresponding to prong parts 34 and 36 and 86, the width or width of which is smaller than the diameter of the wells, the purpose of this measure being to protect the switch through the contact members imparted stiffness and the possibility of discomfort to a seated vehicle occupant to decrease.

As can be seen from FIG. 2, the underside of the paddle part 20 is coated with an adhesive binding agent or an adhesive which is protected by a cover part 88 ¹ . As soon as this cover part is removed, the adhesive or the firmly adhering binding agent secures the switch in position on a paddle of the seat cushion 14 before the switch is covered with the material that forms the seat surface. After the switch is covered, the cover material and pad work together to hold the switch in place next to the seating surface. Thus the invention provides an improved normally open pressure sensitive switch.

309814/0789

It is noted that an alternative according to the invention consists in providing projections only on one of the two contact members. This design is also intended to be based on the idea of the invention be included.

309814/0788

Claims (11)

Claims 1. Normally open pressure dependent switch with a first and a second substantially planar Member made of a flexible dielectric material, a first electrically conductive contact member, the is stacked on a surface of the above-mentioned first member, and having an electrically conductive one second contact member stacked on a surface of the above-mentioned second contact member, the first and second contact members through a resilient spacer having openings therein are kept at a distance from each other, thereby gekennz eichnet that a plurality of protrusions en (50, 52) on both the first (30) and on the second (32) contact member is provided, wherein these projections by embossing or pressing in depressions (50, 52) in the planar members (18, 20) and in their corresponding contact members (30, 32) are formed, the first and the second planargliöder (18, 20) are arranged opposite one another at a distance from one another, so that the projections (50, 52) on the first and second contact members (30, 32) face each other and through the elastic Spacers (42, 46) are kept at a distance from one another, this spacer having openings (44, 48) has, which receive the projections (50, 52) on the contact members (30, 32) and the spacer (42, 46) is compressible about the opposing projections (50, 52) on the first and second contact members (30, 32) interlock, bringing the switch 3098U / 0789 (16) is closed when the planar members (18, 20) have a pressure above a predetermined pressure perpendicular to their opposite surfaces. 2. Normally open · pressure-dependent switch after Claim 1, characterized in that the elastic spacer is a foam pad (42, 46) has firmly adhered between the first and second planar members (18 and 20, respectively) is attached. 3 · Normally open pressure-dependent switch after Claim 1 or 2, characterized in that each contact member (JO, 32) has a flat fork shape with the prongs (34, 36) of the fork separated from each other and the projections (50, 52) along the prongs (34i 36) of the fork are embossed. 4..Normally open pressure-dependent switch after Claim 3> thereby gek ennz e ichn et that the parts (84, 86) of the contact members (30, 32) between each pair of projections (50, 52) along a prong (34, 36) are narrower than the projections (50, 52). 5. Normally open pressure-dependent switch according to claim 3 or 4, characterized in that it is marked ennz e i chn e t, that the projections (50, 52) are frustoconical are. 309814/0789 6. Normally open pressure-dependent switch according to one of claims 3 to 5 »the one seat switch in a vehicle seat for perception the occupation of this seat forms, thereby g e k e η η ζ e i chnet that the switch (16) next to the and arranged parallel to the seat surface (14) of the seat (12) and that of the seat surface (14) on the The next lying planar member (18) is larger in its area than the elastic spacer (42, 46) and the other is planar member (20) so as to shield the switch (16) from electrical damage, if a liquid is poured out onto the seat surface (14) next to the switch (16) will. 7 Normally open pressure-dependent switch according to Claim 6, characterized in that that the first and the second planar members (18, 20) each have the ϊοπα of a paddle and that terminals (5 ^ »56) for connecting the Handle parts (38, 40) of the contact members (30, 32) with an electrical circuit in the handle parts (26, 28) of the pad-shaped parts is, while the areas (34, 36) of the corresponding contact members (30, 32) that can be brought into contact with each other are in the Leaf or paddle parts (22, 24) of the pad-shaped parts are arranged. 8. Normally open pressure-dependent switch according to claim 7 »marked thereby eichnet, that the handle parts (38, 40) of the contactors (30, 32) are laterally offset from one another in order to establish a connection 3Q98U / Q789 - 19 - · of the terminals (54-, 56) connected to it as well as the resulting closing of the switch (16). 9- Normally open pressure dependent switch after Claim 7 or 8, characterized in that the connecting terminals (54- »56) for each Contact member (30, 32) each have a connecting member (62) which has a part (66) for connecting a Supply line (56) and a flattened part (68) which part (38) of the contact member with the handle can come into engagement and has an opening (70) with aligned openings OB-, 74) in the Handle parts (26, 38) of the planar member (18) and the contact member (30) are in alignment, with an insert piece (76) has a portion which is received in the aligned openings (72, 74-), and in lips (78, 82) that ends with the outside of the handle part (26), of the planar member or with the inside of the flattened part (68) of the connecting member in Can come engagement to the engagement between the connecting member (62) and the handle parts (38) of the Maintain contact member (30). 10. Normally open pressure dependent switch after Claim 9 »characterized in that the insert (76) consists of metal, and that with the outside of the handle part (26) of the planar member engageable Mppe (78) is covered with a dielectric member (80) to provide an electrical Connection of the terminals (5 * 0 with a to prevent sliding member of the seat. IQ98U / Q7I8 11. Normally open pressure dependent switch after One of claims 3 to 10, characterized in that each opening (44) in the elastic Spacer (42) is elongate and has a length sufficient to accommodate a prong (34) of the first contact member (30) and a prong (36) of the second contact member (32). 309814/078 « Blank page