CA1158288A - Piezoelectric switch using piezoceramic bending elements and in particular a relay utilizing such elements - Google Patents
Piezoelectric switch using piezoceramic bending elements and in particular a relay utilizing such elementsInfo
- Publication number
- CA1158288A CA1158288A CA000373671A CA373671A CA1158288A CA 1158288 A CA1158288 A CA 1158288A CA 000373671 A CA000373671 A CA 000373671A CA 373671 A CA373671 A CA 373671A CA 1158288 A CA1158288 A CA 1158288A
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- Prior art keywords
- elements
- voltage
- piezoelectric device
- piezoelectric
- visual indication
- Prior art date
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- Expired
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- 238000005452 bending Methods 0.000 title claims abstract description 20
- 239000004020 conductor Substances 0.000 claims abstract description 26
- 230000000007 visual effect Effects 0.000 claims description 11
- 239000003086 colorant Substances 0.000 claims 1
- 239000000463 material Substances 0.000 abstract description 4
- 238000004353 relayed correlation spectroscopy Methods 0.000 abstract 1
- 238000006073 displacement reaction Methods 0.000 description 4
- 230000007935 neutral effect Effects 0.000 description 4
- 239000003990 capacitor Substances 0.000 description 3
- 238000009434 installation Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 241001640034 Heteropterys Species 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- KRTSDMXIXPKRQR-AATRIKPKSA-N monocrotophos Chemical compound CNC(=O)\C=C(/C)OP(=O)(OC)OC KRTSDMXIXPKRQR-AATRIKPKSA-N 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
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- Telephone Set Structure (AREA)
Abstract
PIEZOELECTRIC SWITCH USING PIEZOCERAMIC BENDING ELEMENTS, AND IN PARTICULAR A RELAY UTILIZING SUCH ELEMENTS
Abstract of the Disclosure A piezoceramic device has two layers of piezoceramic material bonded together, the layers polarized in opposite directions.
The device is used to detect, and indicate, a change of voltage between two conductors and specifically is used between the tip and ring lines of a telephone line having more than one extension, to give a line status indication.
- i -
Abstract of the Disclosure A piezoceramic device has two layers of piezoceramic material bonded together, the layers polarized in opposite directions.
The device is used to detect, and indicate, a change of voltage between two conductors and specifically is used between the tip and ring lines of a telephone line having more than one extension, to give a line status indication.
- i -
Description
1 ~ 5 ~
This invention relates to a piezoelectric switch using piezoelectric bending elements, and in particular relates to such elements providing an electric relay switch function as an alternative to a magnetic relay function. A specific example of such a device is as a line status indicator such as in a single telephone line having more than one extension. Various forms of relay actuated switches exist but these are usually current sensitive and thus use power. This, in turn generally requires a separate, additional, power source other than the power source being switched. Thus for a telephone line, a separate power source, other than that of the telephone line, is usually required.
The present invention provides an alternative to the magnetic relay, being an electric relay, which does not consume power.
The application uses the feature of bending of a piezoelectric lamina due to an applied voltage~ Depending upon the power source and use~ the connection of the power source to the lamina, and the way the device or element is used, may vary.
While the present invention will be described broadly, a specific example as applied to a telephone line will be described in detail. In the specific example, for a line status device, a piezoceramic bender element is connected to the pair of conductors of a telephone line and means provided to obtain a signal indicative of bending of the element on application of a voltage.
Particularly an element is connected across the tip and ring conductors of a telephone line whereby when a telephone set connected to the line goes "o~f-hook" the voltage change occurring across the tip and ring conductors actuates the element. Bend of the element is used to give an indication, such as closing contacts to actuate an indicator or by .",, 1 1~5~
causing an appearance at an aperture.
The invention will be readily understood by the following description of certain embodiments, by way of example, in conjunction with the accompanying drawings, in which:-Figure 1 illustrates diagrammatically the basic feature ofthe invention, Figure 2 is a perspective view of an embodiment of the invention with the element in the inactive or non-actuated condition;
Figure 3 is a similar view to that of Figure 2 illustrating the element in an active or actuated condition, Figure 4 is a view of part of a housing illustrating an alternative, or additional feature.
Considering the basic arrangement as illustrated in Figure 1, a piezoceramic bending device is indicated generally at 10~ The element comprises two layers or elements of piezoceram;c material 11 and 12, the layers polarized in opposite directions. The layers 11 and 12 are bonded together and cantilevered at one end 14. The application of an electric field, as by conductors 15, across the two layers or elements causes one layer to expand and the other to contract. The net result is a bending displacement considerably greater than the length variation of either layer.
Thus, if a DC pulse is applied via conductors 15, the elements will bend one way or the other, depending upon the polarity of the pulse, and then return to a neutral position. With a steady DC state, a fairly sudden change in the DC value will cause a quick "pulsing" of the elements depending upon polarity of the initial DC state and the direction of change9 i.e. increase or decrease in voltage.
~15~88 For AC power, the ele~ents will vibrate either side of the neutral position, the amount of displacement depending upon the voltage.
A variation in the AC voltage will result in increased or decreased displace~ent. The bending radius, or displacement is a continuous function of the applied voltage. The device is volta~e sensitive and no power is consumed.
The present invention uses a structure, basically as in Figure 1, to detect or sense, a change in voltage, and give or result in a signal indicative of such a change. It is possible to arrange for the device to give a signal, when a change exceeds a minimum valueO
The specific example illustrated in Figures 2 and 3 is intended for detecting voltage changes in a telephone line, and providing an indication that a change has occurred.
In the appara~us as illustrated in Figure ~ the piezoceramic bending device is cantilevered from one end on the end wall 16 of a housing ~. On the free end of the top layer 11 is formed a contact strip ~ . Extending through the top wall 17 of the housing are two electriral conductors 19. The ends of the conductors 19 overlie the contact strip 18. In the example, the two conductors 19 have in series a source of power, represented by a battery 20 and an indicator lamp 21.
The position of the ends of the conductors can be preposltioned at assembly and have a set, predetermined spatial relationship to the contact strip 18~ Alternatively, as illustrated in Figure 2, the ends of the conductors are a~tached to an insula~ing member 22 which is adjustable by means of a threaded screw 23 passing through a threaded boss 24 on the lower wall ?5 of the housing. By rotation of the screw 23 the position of the ends of the conductors 19 can be raised or 1 ~82{38 lowered relative to the contact strip ~. By this means the apparatus can be preprogrammed to require a predetermined voltage for actuation or can be adjusted to suit different voltage conditions.
In the example, the devi~e 10 is parallel across the tip and ring conductors, indicated by chain dotted lines 30 and 31, by conductors 32 and 33 connected to the layers 11 and 12 respectiYely. On occurrence of a voltage drop between the conductors 30 and 31 a voltage is applied across the device. This causes one layer or element to expand and the other to contract, producing a bending of the device, the bending displacement being considerably greater than the length deformation of either of the two layers. This bending is illustrated in Figure ~ where the contact strip 18 is now in contact with the ends of the conductors 19, electrically connecting them. This would cause the indicator lamp 21 to be lighted.
It will be appreciated that the two elements 11 and 12, are electrically insulating, and that therefore they form a capacitor. When a DC voltage of one polarity is applied across a device~ then there will be an initial deflection of the elements, as shown in Figure 1, but this deflection will slowly disappear as the "capacitor" charges, until a steady state occurs ak the particular voltage. However, when a voltage change occurs, relatively rapidly, there will be an inikial deflection o~
the elements, which then slowly decays. For use in a telephone status indicator, this would result in only a momentary indication. Therefore it is necessary to provide a latching device if a permanent lndication is required. An electrical or electronic latching device is indicated in dotted outline at 34 in Figure 2. The device 34 receives power from the battery 20, and on initial actuation of the elements 11 and 12 contacting ~ 1 5B~8 conductor strip 18~ the latching device is actuated and the lamp 21 is lighted and remains so even a~ter the elements return ~o ~heir neutral position. The device 34 can be deactivated, or switch off by an input from two further conductors 35 contacted by the elements 11 and 12 when they deflect downwards, in Figure 1 when a DC voltage of another polarity is applied. Such different polarities occur for example, when a telephone set goes off hook causing a voltage reduction between tip and ring lines, giving one polarity, and when a telephone set goes on hook causing a voltage rise between tip and ring and giving the alternative polarity.
Figure 3 illustrates the situation at the time the telephone goes off hook.
Alternatively, with an AC voltage, the elements will vibrate either side of neutral. This will give a pulsed output, which, if the frequency is high enough, will effectively give a constant light indicationg insofar as the human eye is concerned. It is readily possible to insert a converter, which can be solid state, between one of the conductors 30 and 31 and the device. Such a converter is indicated at 36 in Figure 3O In such an arrangement the device 10 wi~l vibrate, similar to the dotted outline shown in Figure 1, making contact with the conductors 19 once on each vibration.
A further method would be to provide some means for obviating the capacitor effect resulting from application of a DC voltage across the device.
The device is sensitive to changes in voltage. Thus it can be used in systems where the voltage drop across the conductors 30 and 31 is normally zero and rises to a particular value when some action occurs, ,!
This invention relates to a piezoelectric switch using piezoelectric bending elements, and in particular relates to such elements providing an electric relay switch function as an alternative to a magnetic relay function. A specific example of such a device is as a line status indicator such as in a single telephone line having more than one extension. Various forms of relay actuated switches exist but these are usually current sensitive and thus use power. This, in turn generally requires a separate, additional, power source other than the power source being switched. Thus for a telephone line, a separate power source, other than that of the telephone line, is usually required.
The present invention provides an alternative to the magnetic relay, being an electric relay, which does not consume power.
The application uses the feature of bending of a piezoelectric lamina due to an applied voltage~ Depending upon the power source and use~ the connection of the power source to the lamina, and the way the device or element is used, may vary.
While the present invention will be described broadly, a specific example as applied to a telephone line will be described in detail. In the specific example, for a line status device, a piezoceramic bender element is connected to the pair of conductors of a telephone line and means provided to obtain a signal indicative of bending of the element on application of a voltage.
Particularly an element is connected across the tip and ring conductors of a telephone line whereby when a telephone set connected to the line goes "o~f-hook" the voltage change occurring across the tip and ring conductors actuates the element. Bend of the element is used to give an indication, such as closing contacts to actuate an indicator or by .",, 1 1~5~
causing an appearance at an aperture.
The invention will be readily understood by the following description of certain embodiments, by way of example, in conjunction with the accompanying drawings, in which:-Figure 1 illustrates diagrammatically the basic feature ofthe invention, Figure 2 is a perspective view of an embodiment of the invention with the element in the inactive or non-actuated condition;
Figure 3 is a similar view to that of Figure 2 illustrating the element in an active or actuated condition, Figure 4 is a view of part of a housing illustrating an alternative, or additional feature.
Considering the basic arrangement as illustrated in Figure 1, a piezoceramic bending device is indicated generally at 10~ The element comprises two layers or elements of piezoceram;c material 11 and 12, the layers polarized in opposite directions. The layers 11 and 12 are bonded together and cantilevered at one end 14. The application of an electric field, as by conductors 15, across the two layers or elements causes one layer to expand and the other to contract. The net result is a bending displacement considerably greater than the length variation of either layer.
Thus, if a DC pulse is applied via conductors 15, the elements will bend one way or the other, depending upon the polarity of the pulse, and then return to a neutral position. With a steady DC state, a fairly sudden change in the DC value will cause a quick "pulsing" of the elements depending upon polarity of the initial DC state and the direction of change9 i.e. increase or decrease in voltage.
~15~88 For AC power, the ele~ents will vibrate either side of the neutral position, the amount of displacement depending upon the voltage.
A variation in the AC voltage will result in increased or decreased displace~ent. The bending radius, or displacement is a continuous function of the applied voltage. The device is volta~e sensitive and no power is consumed.
The present invention uses a structure, basically as in Figure 1, to detect or sense, a change in voltage, and give or result in a signal indicative of such a change. It is possible to arrange for the device to give a signal, when a change exceeds a minimum valueO
The specific example illustrated in Figures 2 and 3 is intended for detecting voltage changes in a telephone line, and providing an indication that a change has occurred.
In the appara~us as illustrated in Figure ~ the piezoceramic bending device is cantilevered from one end on the end wall 16 of a housing ~. On the free end of the top layer 11 is formed a contact strip ~ . Extending through the top wall 17 of the housing are two electriral conductors 19. The ends of the conductors 19 overlie the contact strip 18. In the example, the two conductors 19 have in series a source of power, represented by a battery 20 and an indicator lamp 21.
The position of the ends of the conductors can be preposltioned at assembly and have a set, predetermined spatial relationship to the contact strip 18~ Alternatively, as illustrated in Figure 2, the ends of the conductors are a~tached to an insula~ing member 22 which is adjustable by means of a threaded screw 23 passing through a threaded boss 24 on the lower wall ?5 of the housing. By rotation of the screw 23 the position of the ends of the conductors 19 can be raised or 1 ~82{38 lowered relative to the contact strip ~. By this means the apparatus can be preprogrammed to require a predetermined voltage for actuation or can be adjusted to suit different voltage conditions.
In the example, the devi~e 10 is parallel across the tip and ring conductors, indicated by chain dotted lines 30 and 31, by conductors 32 and 33 connected to the layers 11 and 12 respectiYely. On occurrence of a voltage drop between the conductors 30 and 31 a voltage is applied across the device. This causes one layer or element to expand and the other to contract, producing a bending of the device, the bending displacement being considerably greater than the length deformation of either of the two layers. This bending is illustrated in Figure ~ where the contact strip 18 is now in contact with the ends of the conductors 19, electrically connecting them. This would cause the indicator lamp 21 to be lighted.
It will be appreciated that the two elements 11 and 12, are electrically insulating, and that therefore they form a capacitor. When a DC voltage of one polarity is applied across a device~ then there will be an initial deflection of the elements, as shown in Figure 1, but this deflection will slowly disappear as the "capacitor" charges, until a steady state occurs ak the particular voltage. However, when a voltage change occurs, relatively rapidly, there will be an inikial deflection o~
the elements, which then slowly decays. For use in a telephone status indicator, this would result in only a momentary indication. Therefore it is necessary to provide a latching device if a permanent lndication is required. An electrical or electronic latching device is indicated in dotted outline at 34 in Figure 2. The device 34 receives power from the battery 20, and on initial actuation of the elements 11 and 12 contacting ~ 1 5B~8 conductor strip 18~ the latching device is actuated and the lamp 21 is lighted and remains so even a~ter the elements return ~o ~heir neutral position. The device 34 can be deactivated, or switch off by an input from two further conductors 35 contacted by the elements 11 and 12 when they deflect downwards, in Figure 1 when a DC voltage of another polarity is applied. Such different polarities occur for example, when a telephone set goes off hook causing a voltage reduction between tip and ring lines, giving one polarity, and when a telephone set goes on hook causing a voltage rise between tip and ring and giving the alternative polarity.
Figure 3 illustrates the situation at the time the telephone goes off hook.
Alternatively, with an AC voltage, the elements will vibrate either side of neutral. This will give a pulsed output, which, if the frequency is high enough, will effectively give a constant light indicationg insofar as the human eye is concerned. It is readily possible to insert a converter, which can be solid state, between one of the conductors 30 and 31 and the device. Such a converter is indicated at 36 in Figure 3O In such an arrangement the device 10 wi~l vibrate, similar to the dotted outline shown in Figure 1, making contact with the conductors 19 once on each vibration.
A further method would be to provide some means for obviating the capacitor effect resulting from application of a DC voltage across the device.
The device is sensitive to changes in voltage. Thus it can be used in systems where the voltage drop across the conductors 30 and 31 is normally zero and rises to a particular value when some action occurs, ,!
2~
or vice versa, such as a telephone going off-hook. The device can also be used in systems ~here there is for example, normally, some voltage at a predetermined value, the voltage rising as a result of some e~fect or action, or alternatively a voltage decrease occurring as a result such rise or fall in voltage actuating the device. The device is very suitable for telephone lines in that it can be adiuted to accommodate the various voltages which can occur in different conditions, For example in local and domestic installations where the line voltage is generally 48 volts, in PBX installations where the line voltage is 24 volts and on extended loops where the voltage may be as low as 6 volts. It is these varying voltage conditions which can cause problems with other forms of apparatus.
While the device is shown in a housing 15, in Figures 2 and
or vice versa, such as a telephone going off-hook. The device can also be used in systems ~here there is for example, normally, some voltage at a predetermined value, the voltage rising as a result of some e~fect or action, or alternatively a voltage decrease occurring as a result such rise or fall in voltage actuating the device. The device is very suitable for telephone lines in that it can be adiuted to accommodate the various voltages which can occur in different conditions, For example in local and domestic installations where the line voltage is generally 48 volts, in PBX installations where the line voltage is 24 volts and on extended loops where the voltage may be as low as 6 volts. It is these varying voltage conditions which can cause problems with other forms of apparatus.
While the device is shown in a housing 15, in Figures 2 and
3, which can be completely closed, the device can be in an open environment9 provided a support member is available to carry the cantilevered device 10 and some means of pos-itioning tne ends of the conductors 18 and 19 is provided. While the indicator lamp 21 is shown as being high powered from a separate source, it is possible to line power the lamp if desired.
Figure 4 illustrates, very diagrammatically an arrangement in which the bending of the device 10 can be used to give a direct visual indicator. Part of a housing, such as a telephone housing, is indicated at 40, the device bein~ viewed end on and indicated by the dotted outline 41 at its inactive or unactuated position. An aperture 42 is formed in the housing 40 spaced such that when the device 10 bends, its end surface will be visible through the aperture 42. The end of the device can be coloured so as to make it more readily visible through the aperture. The arrangement as illustrated in Figures 2 and 3 could readily be modified to 1 :15~2~
give such a visual indicationg by omitting the conductors 19, member 22 and screw 23. Contact strip 18 would not be required and the end wall 43 of the housing 15 would be positioned adjacent to ~he ends of the element 10.
Other arrangements can readily be envisaged. For example, instead of the element moving into contact withe conductors, as in Figures 2 and 3, the element can be caused to move an indicator and it can be arranged that movement of the indicator occurs only with a predetermined movement or deformation oF the element. This can be used, as with the member 22 and screw 23, to acco~odate different voltage conditions.
It is an advantage, for programming the element, that the bending radius of the element is a continuous function of the applied voltage.
The material of the layers 11 and 12 is a piezoceramic, sold by Gulton Industries Inc., of New Jersey, Pie70 Products division. The material is a ceramic having pie~o electric properties and having the capability of being polarized in a predetermined direction.
A device in accordance with the invention is a solid state device and has the reliability small size, and compactness of such devices. It has very good electrical isolation with very low leakage, a distinc~ advantage when used across a telephone line. The actuation of the device is accurately predicted and can be made to handle a wide range of voltage and current. Thus voltage in the ranges of 10 to 100 are readily obtained, in the milli-watt range. The device is an electrical equivalent oF a magnetic relay and can replace such relays. Switching speeds equal to or greater than that of the conventional magnetic relay can be obtained.
.. '
Figure 4 illustrates, very diagrammatically an arrangement in which the bending of the device 10 can be used to give a direct visual indicator. Part of a housing, such as a telephone housing, is indicated at 40, the device bein~ viewed end on and indicated by the dotted outline 41 at its inactive or unactuated position. An aperture 42 is formed in the housing 40 spaced such that when the device 10 bends, its end surface will be visible through the aperture 42. The end of the device can be coloured so as to make it more readily visible through the aperture. The arrangement as illustrated in Figures 2 and 3 could readily be modified to 1 :15~2~
give such a visual indicationg by omitting the conductors 19, member 22 and screw 23. Contact strip 18 would not be required and the end wall 43 of the housing 15 would be positioned adjacent to ~he ends of the element 10.
Other arrangements can readily be envisaged. For example, instead of the element moving into contact withe conductors, as in Figures 2 and 3, the element can be caused to move an indicator and it can be arranged that movement of the indicator occurs only with a predetermined movement or deformation oF the element. This can be used, as with the member 22 and screw 23, to acco~odate different voltage conditions.
It is an advantage, for programming the element, that the bending radius of the element is a continuous function of the applied voltage.
The material of the layers 11 and 12 is a piezoceramic, sold by Gulton Industries Inc., of New Jersey, Pie70 Products division. The material is a ceramic having pie~o electric properties and having the capability of being polarized in a predetermined direction.
A device in accordance with the invention is a solid state device and has the reliability small size, and compactness of such devices. It has very good electrical isolation with very low leakage, a distinc~ advantage when used across a telephone line. The actuation of the device is accurately predicted and can be made to handle a wide range of voltage and current. Thus voltage in the ranges of 10 to 100 are readily obtained, in the milli-watt range. The device is an electrical equivalent oF a magnetic relay and can replace such relays. Switching speeds equal to or greater than that of the conventional magnetic relay can be obtained.
.. '
Claims (7)
PROPERTY OF PRIVILEGE IS CLAIMED ARE AS FOLLOWS:
1. A piezoelectric operated indicator device for use in telephone status line indicators, said device comprising:
a piezoelectric device having two piezoelectric elements bonded together as a single member and cantilever mounted at one end and having an opposite free end, said elements being oppositely polarized;
means for applying an electrical voltage across said two elements, said two elements being in electrical series whereby said piezoelectric device bends From an unbent position in a first or a second direction when a voltage of a first or a second polarity, respectively, is applied; and means responsive to the bending of said piezoelectric device for producing a visual indication of said bending whereby said visual indication producing means provides an indication of a voltage of a predetermined polarity being applied across said series connected elements.
a piezoelectric device having two piezoelectric elements bonded together as a single member and cantilever mounted at one end and having an opposite free end, said elements being oppositely polarized;
means for applying an electrical voltage across said two elements, said two elements being in electrical series whereby said piezoelectric device bends From an unbent position in a first or a second direction when a voltage of a first or a second polarity, respectively, is applied; and means responsive to the bending of said piezoelectric device for producing a visual indication of said bending whereby said visual indication producing means provides an indication of a voltage of a predetermined polarity being applied across said series connected elements.
2. A piezoelectric operated indicator device for use in telephone status line indicators, said device comprising;
a piezoelectric device having two piezoelectric elements bonded together, said elements being oppositely polarized and being connected as a single member which is cantilever mounted at one end and has an opposite free end;
means for applying an electrical voltage across said two elements, said two elements being in electrical series whereby said piezoelectric device bends from an unbent position in a first or a second direction when a voltage of a first or a second polarity, respectively, is applied; and means responsive to the bending of said piezoelectric device for producing a visual indication of said bending whereby said visual indication producing means provides an indication of a voltage of a predetermined polarity being applied across said series connected elements, said visual indication producing means comprising a wall having an opening formed therein, said opening being positioned such that a portion of said piezoelectric device is visible in said opening when said piezoelectric device is in one of the bent and unbent positions, and said portion of said piezoelectric device is not visible in said opening when said piezoelectric device is in another of said bent or unbent positions.
a piezoelectric device having two piezoelectric elements bonded together, said elements being oppositely polarized and being connected as a single member which is cantilever mounted at one end and has an opposite free end;
means for applying an electrical voltage across said two elements, said two elements being in electrical series whereby said piezoelectric device bends from an unbent position in a first or a second direction when a voltage of a first or a second polarity, respectively, is applied; and means responsive to the bending of said piezoelectric device for producing a visual indication of said bending whereby said visual indication producing means provides an indication of a voltage of a predetermined polarity being applied across said series connected elements, said visual indication producing means comprising a wall having an opening formed therein, said opening being positioned such that a portion of said piezoelectric device is visible in said opening when said piezoelectric device is in one of the bent and unbent positions, and said portion of said piezoelectric device is not visible in said opening when said piezoelectric device is in another of said bent or unbent positions.
3. The indicator device as set forth in claim 1 wherein said voltage applying means comprises electrical lines connected between the tip and ring conductors of a telephone line for applying a voltage across said tip and ring conductors to said piezoelectric device.
4. The indicator device as set forth in claim 1 wherein said visual indication producing means comprises an electric light, a power source for said electric light, a pair of electrical contacts positioned to be actuated by said piezoelectric device when said piezoelectric device bends to a first position in response to a voltage of a predetermined polarity, and latch means for continuously connecting said power source to said electric light in response to a momentary actuation of said contacts.
5. A piezoelectric operated indicator device for use in telephone status line indicators, said device comprising:
a piezoelectric device having two piezoelectric elements bonded together, said elements being oppositely polarized;
means for applying an electrical voltage across said two elements, said two elements being in electrical series whereby said piezoelectric device bends from an unbent position in a first or a second direction when a voltage of a first or a second polarity, respectively, is applied; and means responsive to the bending of said piezoelectric device for producing a visual indication of said bending whereby said visual indication producing means provides an indication of a voltage of a predetermined polarity being applied across said series connected elements, said visual indication producing means comprising an electric light, a power source for said electric light, a pair of electrical contacts positioned to be actuated by said piezoelectric device when said piezoelectric device bends to a first position in response to a voltage of a predetermined polarity, and latch means for continuously connecting said power source to said electric light in response to a momentary actuation of said contacts, and wherein said indicator device further includes a second set of electrical contacts positioned to be actuated by said piezoelectric device when said piezoelectric device is in a second position, and wherein said latch means is responsive to said second set of contacts to disconnect said power source from said electric light when said second contacts are momentarily actuated.
a piezoelectric device having two piezoelectric elements bonded together, said elements being oppositely polarized;
means for applying an electrical voltage across said two elements, said two elements being in electrical series whereby said piezoelectric device bends from an unbent position in a first or a second direction when a voltage of a first or a second polarity, respectively, is applied; and means responsive to the bending of said piezoelectric device for producing a visual indication of said bending whereby said visual indication producing means provides an indication of a voltage of a predetermined polarity being applied across said series connected elements, said visual indication producing means comprising an electric light, a power source for said electric light, a pair of electrical contacts positioned to be actuated by said piezoelectric device when said piezoelectric device bends to a first position in response to a voltage of a predetermined polarity, and latch means for continuously connecting said power source to said electric light in response to a momentary actuation of said contacts, and wherein said indicator device further includes a second set of electrical contacts positioned to be actuated by said piezoelectric device when said piezoelectric device is in a second position, and wherein said latch means is responsive to said second set of contacts to disconnect said power source from said electric light when said second contacts are momentarily actuated.
6. The indicator device as set forth in claim 2 wherein said wall and said portion of said piezoelectric device have contrasting colors.
7. The indicator device as set forth in claim 2 or 6 wherein said portion of said piezoelectric device is said free end.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US16700280A | 1980-07-09 | 1980-07-09 | |
| US167,002 | 1993-12-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1158288A true CA1158288A (en) | 1983-12-06 |
Family
ID=22605543
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000373671A Expired CA1158288A (en) | 1980-07-09 | 1981-03-23 | Piezoelectric switch using piezoceramic bending elements and in particular a relay utilizing such elements |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1158288A (en) |
-
1981
- 1981-03-23 CA CA000373671A patent/CA1158288A/en not_active Expired
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