CA1125822A - Push button operated low force switch - Google Patents
Push button operated low force switchInfo
- Publication number
- CA1125822A CA1125822A CA335,039A CA335039A CA1125822A CA 1125822 A CA1125822 A CA 1125822A CA 335039 A CA335039 A CA 335039A CA 1125822 A CA1125822 A CA 1125822A
- Authority
- CA
- Canada
- Prior art keywords
- separator
- cover
- plate
- switch
- force
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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- Push-Button Switches (AREA)
Abstract
PUSH BUTTON OPERATED LOW FORCE SWITCH
ABSTRACT
A pressure plate is depressed to actuate a momen-tary closing switch by exerting pressure on a flexible cover on the switch through a semi-rigid separator and an elastomeric diaphragm. A projection on the plate contacts the separator to focus the pressure on a por-tion thereof. A foam ring is disposed around the pro-jection and between the plate and separator and is compressed as the plate is depressed.
ABSTRACT
A pressure plate is depressed to actuate a momen-tary closing switch by exerting pressure on a flexible cover on the switch through a semi-rigid separator and an elastomeric diaphragm. A projection on the plate contacts the separator to focus the pressure on a por-tion thereof. A foam ring is disposed around the pro-jection and between the plate and separator and is compressed as the plate is depressed.
Description
~25B22 B~CKGROUND OF THE INVENTION
This invention relates generally to low ~or~e switches, and, in particular, ruggedized low force switches for applications such as elevator control buttons.
Elevator control buttons are provided in hallways and elevator cars to reques~ and direct elevator ser-vice. A particularly popular bu~ton utilizes a cold cathode gas tube actuated by the mere touch of the user's finger. The tube also glows to provide illu-mination indicating a service xequest. Its activation results from the capacitance associated with the user's finger when touching a control terminal on the butto~
connected ~o the gas tube. It îs quite understandable that a particularly appealing feature of this button is the "soft touch" imparted to the user simply because no mechanical motion or force is required for its activatiun. Furthermore, because no force is required, the temptation to pound repeatedly on the button is minimized significantly. The application of the cold gas tube in an elevator control button is the subject of the following U.S. patents, wherein its operation is described in much amplified detail: 2~525,767; 2352S,768 and 2,525,769.
In certain other elevator installations3 meohanical ~ 11251~22 type switches are used in lieu o~ the gas tube~ Need-less to say, it is still preerred and desired to achieve the "soft touch~O In fact~ some of these installation~ are retrofits or the gas tube button and use a switch apparatus devised by applicant and which has been made the subject of patent applications, to which further reference is unnecessary.
An exceptionally appealing way to achieve this end is to use low force switches, particularly those characterized by nearly impercep~ible movement for actuation and more importantly a very low force require-- ment, usually about 1.5 grams. A particularly attractlve switch of this type contains a small dot of conductive material mounted on a flexible cover. A light ~orce is applied to the cover, in the area o the dot, in order to press its dot against a grid of condu~ive ~aterial connected to the switch terminals. The dot . shorts the grid to complete the circuit between the terminals. The flexible cover is usually ~hin and has inherent resiliency which causes the switch to recover to its normal nonactuated condi~ion when ~he force is remo~Pd therefrom. Suffice it ~o say, these swi~ches are particularly fragile and delicate; sharp blows or excessive or concentrated force on the cover can result in damage thereto, not to mentlon the dot - and the grid. The result can be a drama~ic reduction , ~3 , .~
~ ~ 5 ~ Z 2 in useful switch life.
An elevator control button, needless to say, is particularly vulnerable to harsh and abusive treat~
ment from its various, sundry users. Practical con-siderations dictate that an elevator control button must contain a touch or pressure plate of reasonably large surface area so as to enable a user to conveniently touch it. Generally speaking, a useful area will be considerably larger than the area on the cover of these low force switches to which force is applied in order to actuate it. The force applied to the pressure plate therefore must be concentrated into a small area for actuation, and, hence, there is consi-derable possibility that the switch will be damaged by a user who applies too much pressure, sustained pressure or pounds repeatedly on the button. For this reason, the use of commercially available low force switches of this type, ~s well as other related types, in elevator control buttons has been heretofore imprac- .
tical, principally because the switch would have an undesirably short service life.
SUMMA~Y OF THE INVENTION
Objects of the present invention include providing a rugged low force switch apparatus particularly~ but -4^
~Z~8~
not exclusively, suited for elevator control but~ons in that a "soft touch" operation is achieved along with a satisfactory service llfe.
In accordance with the present inventio~, a low force switch of the general type actuated by applying pressure to a flexible cover or pressure responsive service thereon is actuated not by applying pressure directly to the cover, but rather through a semi-rigid separator over which the force is nearly evenly distributed and an elastomeric diaphragm providing a uniform shock absorbing interface or pad between the separator and the cover. To actuate this switch, pressure is applied to a pressure or touch plate which contains a projection for focusing or centering the pressure onto a portion of the separator. In response, this portion assumes a smooth curved shape oriented towards the cover. The pressure is substantially evenly distributed over this curve. A ~eature of the separator is its inheren~
characteristic not to conform to the shape of the projection applying pressure thereto. This assures that the desired smooth curvature is attained. A corres-ponding conformlng portion of the elastomeric diaphragm is thrust or pushed against the cover in order to apply pressure to the cover to actuate the switch. A
contrasting feature here of the diaphragm ;s i~s inheren~
~ZSl32'~
characteristic to conform to the curve in the separator, In doing so, it ~ills any voids between the separator and ~he cover, and, o~ equal importance, provides a uniorm and shock absorbing inter~ace. Herlce; the separator and diaphragm provide an exceptionally effec~
tive medium through which pressure is distributed on the coverO An additional feature is the use of a foam ring between the plate and separator to provide resilient support ~or the plate to prevent it from tipping or skewing as it is depressed. This is important since it maximizes the surface area of the curve and that ~ini~izes the pressure on the cover.
Additional objects, benefits, features and appli-cations of the present invention to ele~ator control buttons as well as other control applications will bacome apparent to those skilled in the art from the following drawing, detailed descript~~on and claims wherein:
DESCRIPTION OF THE DRAWING
FIG. 1 is a cross section o a low force switch appara~us in accordance with the presen~ invention shown in its actuated state and situated in a simpli-fied housing therefor, partially shown; and FIG. 2 is a cross sec~ion of the apparatus in FIG.
1 in i~s nonactuated state.
~Z5~
DETAILE~ ~
In FIG. 1~ a low force switch 10 is shown ln an actuated condition. The switch includes a flexible cover 12 to which pressure is applied to push a con-tact 14, a dot of conductive material thereon) against a grid contact consisting of several conductive strips 18 mounted on a riKid back plate 20 and to which the switch terminals 22 are connect~d. In this manner the terminals are connected as the strips 18 are shorted together through the contact 14. This switch is what is commonly referred to as a low ~orce button or wafer switch, and a preerred version is co~mercially avail-able from Centralab ~lectronics Division of Globe Union of Milwaukee, Wisconsin, Model 25MD2000N7505. This particular switch usually requires appro~imately 1.5 grams of actuatin~ force upon the ~lexible eovering to bring the contacts together for actuation. Other si~ilar operatLng switches may also be available.
Finger pressure is applied ~o a pressure plate 24 in order to bring the contacts toge~her. Speci~ically, the pressure plate 24 includes a projaction 26 which is pushed against a portion of a pliable or semi-rigid separator 28 to produce the curve or bulge therein that is shown in FIG. 1. A corresponding and conforming bulge is produced in an elastomeric diaphragm 30 directly adja-cent as the plate is depressed and through this dlaphragm the pressure from the proj ection 26 is transmit~ed to the cover 12, whereupon the switch is actuated as shown.
The separator is constructed of a plastic or thin me~al to give it a pliable or semi-rigid characterîstic so that it inherently produces a smooth curve throughout the area contacted by the front ~ace of the projection 26. Xn other words, it cannot conform to the exact sha~e of the projection but instead defines a curve between its ends. The separatox can be constructed o Mylar* plastic 016 inches thick, thi~ being the preferred dimensions in conjunction with the previous Centralab switch in an elevator control button, although dif~erent dimensions can provide different performance character-istics for other applications. Thus, the separator 28 functions as a ~orce or pressure distributor in the switch apparatus.
The elastomeric diaphragm 30 provides a shock absorption inter~ace between the separator 28 and the cover 12, and of equal importance, it serves as a soft pad to fill any voids or spaces betwee~ the separator and cover to maximize the area on the cover to which the pressure is applied. In FI&. 2, this is depicted as the sligh~ flattening ~n ~he side of ~he diaphragm as it is pushed against the cover. The *Trademark ~ ~ ~ 5 ~ ~ ~
opposite side, as shown, conforms to the curved portlon of the separator at the same time. The diaphragm is cons~ructed o~ rubber~ i.e. neoprene a~d may be about .005 inches thick. It is important to observe that without the presence of the separator, the diaphragm would readily conform to the shape of the projection and, thus, an uneven pressure distribution upon the cover might result. Analogously, without the presence of the diaphragm, the plastic separator would not necessarily have a smooth resilient interface with the cover and an undesirable pressure distribution might also result. It is obvious therefore that the cooperation between the separator and the diaphragm is an integral ~acet of the invention.
As the plate 24 is depressed, a foam ring 32, located around the projection and between the separator and the plate is compressed. This ring is constructed of a foam material, i.e. urethane; its important feature . is that as the plate is depressed 9 it provides coaxial resiliency, which opposes inward depression of the plate as it moves with walls 34 of the housing or container for the switch apparatus. The housing con-figuration beyond the walls 34 ls not specificall~ shown~
as it has no relevance to the invention, but any configur-ation which includes the walls will suffice. In the instanc~ of an ele~ator button, for example, prior ar~
~S8Z2 housings may be used so as to provide a button with ~he same appearance and illuminatlon . The e~ect of th~
ring is not only to provide additional rebound for the plate after the fin~er is removed, but axial support to prevent skewing or tipping of the plate. Otherwise, it is possibLe that less than the ~ntire front face of the projection 26 will contact the separator; that can result in a considerably smaller curve in the separator;
hence, the pressure on the cover 12 would be greater.
Consequently, the xing is important i~ maximizing the area of the curve on the separator so as ~o minimize the pressure applied to the cover. As shown, in its relaxed condition (FIG. 2~ its thickness is about the height of the projection 26. This is not critical, however, except that it determines the distance between the edge o~ the projection of the cover in the non-actua~ed state. The cover 12 is also semi-rigid and, thus, rebounds away when pressure is xemoved to ope~
the circuit betwecn the terminals 22 as demonstrated in FIG. 2. With the switch thereby nonactuated, the separator 28 and diaphragm 30 are generally planar, and the pressure plate is moved back with the foam ring fully expanded.
The overall thickness o the plastic separator de~ermines the amount of force required to actuate the ?
5~Z~
switch. IE it is extremely thick, a signif:Lcank amounk of force is needed to produce the required curvature -to move the cover the proper dis~ance to short the grids 18 with contact 14. On the other hand, if the separator is made extremely thin, the switch can be actuated i~
response to aberrational forces such as changes in atmospheric condition when users walk by. This is because ampliication results from the simple fact that the surface area on the pressure plate 26 to which ~.
force is applied (the ~ront 38~ is significantly larger than the area of the projection 26 that contacts the separator.
- The foregoing mentioned dimensions with respec~ to the separator and diaphragm in the particular utilization of the Centralab model switch have been found to be satisfactory in an elevator control button where the standard is the desired "soft touch" ~eel vls-a-~is the cold gas tube button of the prior art. Needless to say, the utilization of the apparatus of the present i~vention in other applications therefore may require different dimensions, even if the aforementioned switch is u~iliæed Such applications might be pinball machines~ controls for home, amu~ement games and controls for automobile ~ehicles.
In actuality, the present apparatus will ha~e application in any installation wherein the low force switch of this ~ ~ 2~ ~ ~ Z
variety (that is those using a pressure responsive cover for actuatîon), but where it is also desired to achieve additional ruggedness for increased reliability. As mentioned before, however, the housing for the apparatus is not significa~t to its operation; although it can be used in signiicantly dif~erent housings geared to specific application needs. For example, in an elevator button, the housing could be illuminated and suitably constructed in the configuration of the housing for the cold gas tube in the aforementioned patents; only the internals of the housing are changed to effect a retro-: fit in this instance.
While the foregoing is a descrip~ion of ~he preferred embodiment of the best mode for the present invention now known, there will undoubtedly be various modifications a~d variations thereto which nevertheless embrace the invention 19 true scope and spirit. The claims ~hat follow are intended to be construed as claiming all such modifications and varia~ions.
This invention relates generally to low ~or~e switches, and, in particular, ruggedized low force switches for applications such as elevator control buttons.
Elevator control buttons are provided in hallways and elevator cars to reques~ and direct elevator ser-vice. A particularly popular bu~ton utilizes a cold cathode gas tube actuated by the mere touch of the user's finger. The tube also glows to provide illu-mination indicating a service xequest. Its activation results from the capacitance associated with the user's finger when touching a control terminal on the butto~
connected ~o the gas tube. It îs quite understandable that a particularly appealing feature of this button is the "soft touch" imparted to the user simply because no mechanical motion or force is required for its activatiun. Furthermore, because no force is required, the temptation to pound repeatedly on the button is minimized significantly. The application of the cold gas tube in an elevator control button is the subject of the following U.S. patents, wherein its operation is described in much amplified detail: 2~525,767; 2352S,768 and 2,525,769.
In certain other elevator installations3 meohanical ~ 11251~22 type switches are used in lieu o~ the gas tube~ Need-less to say, it is still preerred and desired to achieve the "soft touch~O In fact~ some of these installation~ are retrofits or the gas tube button and use a switch apparatus devised by applicant and which has been made the subject of patent applications, to which further reference is unnecessary.
An exceptionally appealing way to achieve this end is to use low force switches, particularly those characterized by nearly impercep~ible movement for actuation and more importantly a very low force require-- ment, usually about 1.5 grams. A particularly attractlve switch of this type contains a small dot of conductive material mounted on a flexible cover. A light ~orce is applied to the cover, in the area o the dot, in order to press its dot against a grid of condu~ive ~aterial connected to the switch terminals. The dot . shorts the grid to complete the circuit between the terminals. The flexible cover is usually ~hin and has inherent resiliency which causes the switch to recover to its normal nonactuated condi~ion when ~he force is remo~Pd therefrom. Suffice it ~o say, these swi~ches are particularly fragile and delicate; sharp blows or excessive or concentrated force on the cover can result in damage thereto, not to mentlon the dot - and the grid. The result can be a drama~ic reduction , ~3 , .~
~ ~ 5 ~ Z 2 in useful switch life.
An elevator control button, needless to say, is particularly vulnerable to harsh and abusive treat~
ment from its various, sundry users. Practical con-siderations dictate that an elevator control button must contain a touch or pressure plate of reasonably large surface area so as to enable a user to conveniently touch it. Generally speaking, a useful area will be considerably larger than the area on the cover of these low force switches to which force is applied in order to actuate it. The force applied to the pressure plate therefore must be concentrated into a small area for actuation, and, hence, there is consi-derable possibility that the switch will be damaged by a user who applies too much pressure, sustained pressure or pounds repeatedly on the button. For this reason, the use of commercially available low force switches of this type, ~s well as other related types, in elevator control buttons has been heretofore imprac- .
tical, principally because the switch would have an undesirably short service life.
SUMMA~Y OF THE INVENTION
Objects of the present invention include providing a rugged low force switch apparatus particularly~ but -4^
~Z~8~
not exclusively, suited for elevator control but~ons in that a "soft touch" operation is achieved along with a satisfactory service llfe.
In accordance with the present inventio~, a low force switch of the general type actuated by applying pressure to a flexible cover or pressure responsive service thereon is actuated not by applying pressure directly to the cover, but rather through a semi-rigid separator over which the force is nearly evenly distributed and an elastomeric diaphragm providing a uniform shock absorbing interface or pad between the separator and the cover. To actuate this switch, pressure is applied to a pressure or touch plate which contains a projection for focusing or centering the pressure onto a portion of the separator. In response, this portion assumes a smooth curved shape oriented towards the cover. The pressure is substantially evenly distributed over this curve. A ~eature of the separator is its inheren~
characteristic not to conform to the shape of the projection applying pressure thereto. This assures that the desired smooth curvature is attained. A corres-ponding conformlng portion of the elastomeric diaphragm is thrust or pushed against the cover in order to apply pressure to the cover to actuate the switch. A
contrasting feature here of the diaphragm ;s i~s inheren~
~ZSl32'~
characteristic to conform to the curve in the separator, In doing so, it ~ills any voids between the separator and ~he cover, and, o~ equal importance, provides a uniorm and shock absorbing inter~ace. Herlce; the separator and diaphragm provide an exceptionally effec~
tive medium through which pressure is distributed on the coverO An additional feature is the use of a foam ring between the plate and separator to provide resilient support ~or the plate to prevent it from tipping or skewing as it is depressed. This is important since it maximizes the surface area of the curve and that ~ini~izes the pressure on the cover.
Additional objects, benefits, features and appli-cations of the present invention to ele~ator control buttons as well as other control applications will bacome apparent to those skilled in the art from the following drawing, detailed descript~~on and claims wherein:
DESCRIPTION OF THE DRAWING
FIG. 1 is a cross section o a low force switch appara~us in accordance with the presen~ invention shown in its actuated state and situated in a simpli-fied housing therefor, partially shown; and FIG. 2 is a cross sec~ion of the apparatus in FIG.
1 in i~s nonactuated state.
~Z5~
DETAILE~ ~
In FIG. 1~ a low force switch 10 is shown ln an actuated condition. The switch includes a flexible cover 12 to which pressure is applied to push a con-tact 14, a dot of conductive material thereon) against a grid contact consisting of several conductive strips 18 mounted on a riKid back plate 20 and to which the switch terminals 22 are connect~d. In this manner the terminals are connected as the strips 18 are shorted together through the contact 14. This switch is what is commonly referred to as a low ~orce button or wafer switch, and a preerred version is co~mercially avail-able from Centralab ~lectronics Division of Globe Union of Milwaukee, Wisconsin, Model 25MD2000N7505. This particular switch usually requires appro~imately 1.5 grams of actuatin~ force upon the ~lexible eovering to bring the contacts together for actuation. Other si~ilar operatLng switches may also be available.
Finger pressure is applied ~o a pressure plate 24 in order to bring the contacts toge~her. Speci~ically, the pressure plate 24 includes a projaction 26 which is pushed against a portion of a pliable or semi-rigid separator 28 to produce the curve or bulge therein that is shown in FIG. 1. A corresponding and conforming bulge is produced in an elastomeric diaphragm 30 directly adja-cent as the plate is depressed and through this dlaphragm the pressure from the proj ection 26 is transmit~ed to the cover 12, whereupon the switch is actuated as shown.
The separator is constructed of a plastic or thin me~al to give it a pliable or semi-rigid characterîstic so that it inherently produces a smooth curve throughout the area contacted by the front ~ace of the projection 26. Xn other words, it cannot conform to the exact sha~e of the projection but instead defines a curve between its ends. The separatox can be constructed o Mylar* plastic 016 inches thick, thi~ being the preferred dimensions in conjunction with the previous Centralab switch in an elevator control button, although dif~erent dimensions can provide different performance character-istics for other applications. Thus, the separator 28 functions as a ~orce or pressure distributor in the switch apparatus.
The elastomeric diaphragm 30 provides a shock absorption inter~ace between the separator 28 and the cover 12, and of equal importance, it serves as a soft pad to fill any voids or spaces betwee~ the separator and cover to maximize the area on the cover to which the pressure is applied. In FI&. 2, this is depicted as the sligh~ flattening ~n ~he side of ~he diaphragm as it is pushed against the cover. The *Trademark ~ ~ ~ 5 ~ ~ ~
opposite side, as shown, conforms to the curved portlon of the separator at the same time. The diaphragm is cons~ructed o~ rubber~ i.e. neoprene a~d may be about .005 inches thick. It is important to observe that without the presence of the separator, the diaphragm would readily conform to the shape of the projection and, thus, an uneven pressure distribution upon the cover might result. Analogously, without the presence of the diaphragm, the plastic separator would not necessarily have a smooth resilient interface with the cover and an undesirable pressure distribution might also result. It is obvious therefore that the cooperation between the separator and the diaphragm is an integral ~acet of the invention.
As the plate 24 is depressed, a foam ring 32, located around the projection and between the separator and the plate is compressed. This ring is constructed of a foam material, i.e. urethane; its important feature . is that as the plate is depressed 9 it provides coaxial resiliency, which opposes inward depression of the plate as it moves with walls 34 of the housing or container for the switch apparatus. The housing con-figuration beyond the walls 34 ls not specificall~ shown~
as it has no relevance to the invention, but any configur-ation which includes the walls will suffice. In the instanc~ of an ele~ator button, for example, prior ar~
~S8Z2 housings may be used so as to provide a button with ~he same appearance and illuminatlon . The e~ect of th~
ring is not only to provide additional rebound for the plate after the fin~er is removed, but axial support to prevent skewing or tipping of the plate. Otherwise, it is possibLe that less than the ~ntire front face of the projection 26 will contact the separator; that can result in a considerably smaller curve in the separator;
hence, the pressure on the cover 12 would be greater.
Consequently, the xing is important i~ maximizing the area of the curve on the separator so as ~o minimize the pressure applied to the cover. As shown, in its relaxed condition (FIG. 2~ its thickness is about the height of the projection 26. This is not critical, however, except that it determines the distance between the edge o~ the projection of the cover in the non-actua~ed state. The cover 12 is also semi-rigid and, thus, rebounds away when pressure is xemoved to ope~
the circuit betwecn the terminals 22 as demonstrated in FIG. 2. With the switch thereby nonactuated, the separator 28 and diaphragm 30 are generally planar, and the pressure plate is moved back with the foam ring fully expanded.
The overall thickness o the plastic separator de~ermines the amount of force required to actuate the ?
5~Z~
switch. IE it is extremely thick, a signif:Lcank amounk of force is needed to produce the required curvature -to move the cover the proper dis~ance to short the grids 18 with contact 14. On the other hand, if the separator is made extremely thin, the switch can be actuated i~
response to aberrational forces such as changes in atmospheric condition when users walk by. This is because ampliication results from the simple fact that the surface area on the pressure plate 26 to which ~.
force is applied (the ~ront 38~ is significantly larger than the area of the projection 26 that contacts the separator.
- The foregoing mentioned dimensions with respec~ to the separator and diaphragm in the particular utilization of the Centralab model switch have been found to be satisfactory in an elevator control button where the standard is the desired "soft touch" ~eel vls-a-~is the cold gas tube button of the prior art. Needless to say, the utilization of the apparatus of the present i~vention in other applications therefore may require different dimensions, even if the aforementioned switch is u~iliæed Such applications might be pinball machines~ controls for home, amu~ement games and controls for automobile ~ehicles.
In actuality, the present apparatus will ha~e application in any installation wherein the low force switch of this ~ ~ 2~ ~ ~ Z
variety (that is those using a pressure responsive cover for actuatîon), but where it is also desired to achieve additional ruggedness for increased reliability. As mentioned before, however, the housing for the apparatus is not significa~t to its operation; although it can be used in signiicantly dif~erent housings geared to specific application needs. For example, in an elevator button, the housing could be illuminated and suitably constructed in the configuration of the housing for the cold gas tube in the aforementioned patents; only the internals of the housing are changed to effect a retro-: fit in this instance.
While the foregoing is a descrip~ion of ~he preferred embodiment of the best mode for the present invention now known, there will undoubtedly be various modifications a~d variations thereto which nevertheless embrace the invention 19 true scope and spirit. The claims ~hat follow are intended to be construed as claiming all such modifications and varia~ions.
Claims (4)
1. A switch apparatus, comprising:
a low force switch of the type having a resilient cover thereon to which force is applied for actuating said switch;
a pressure plate which is depressed for applying said actuating force to said cover, said plate includ-ing a force concentrating projection having a flat surface through which said force is applied to said cover; and a generally planar semirigid separator; and a generally planar elastomeric diaphragm;
said separator and said diaphragm being disposed between said plate and said cover; said actuat-ing force being transmitted from said plate to said cover as said projection is forced against a portion of said separator, said portion thereby forcing a corresponding portion of said diaphragm against said cover;
said separator being characterized in that said portion is smoothly curved and said actuating force is substantially evenly distributed over said portion; and said diaphragm being characterized in that said corresponding portion conforms to said separator portion and provides a cushion between said separator portion and said cover.
a low force switch of the type having a resilient cover thereon to which force is applied for actuating said switch;
a pressure plate which is depressed for applying said actuating force to said cover, said plate includ-ing a force concentrating projection having a flat surface through which said force is applied to said cover; and a generally planar semirigid separator; and a generally planar elastomeric diaphragm;
said separator and said diaphragm being disposed between said plate and said cover; said actuat-ing force being transmitted from said plate to said cover as said projection is forced against a portion of said separator, said portion thereby forcing a corresponding portion of said diaphragm against said cover;
said separator being characterized in that said portion is smoothly curved and said actuating force is substantially evenly distributed over said portion; and said diaphragm being characterized in that said corresponding portion conforms to said separator portion and provides a cushion between said separator portion and said cover.
2. A switch apparatus according to claim 1 wherein said separator is constructed of a plastic material, said diaphragm is constructed of a rubber material, and said diaphragm is substantially thinner than said separator.
3. A switch apparatus according to claim 1, further comprising: means disposed around said projec-tion for resiliently supporting said plate as it is depressed for maximizing the contact area between said projection and said separator.
4. A switch apparatus according to claim 3, wherein said means comprises a ring which is com-pressed as said plate is depressed, said ring being constructed of a foam material.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US96865378A | 1978-12-11 | 1978-12-11 | |
| US968,653 | 1992-10-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1125822A true CA1125822A (en) | 1982-06-15 |
Family
ID=25514578
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA335,039A Expired CA1125822A (en) | 1978-12-11 | 1979-09-05 | Push button operated low force switch |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1125822A (en) |
-
1979
- 1979-09-05 CA CA335,039A patent/CA1125822A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |