GB1602056A - Method and circuit arrangement for damping contact vibrations in a dry-reed switch - Google Patents
Method and circuit arrangement for damping contact vibrations in a dry-reed switch Download PDFInfo
- Publication number
- GB1602056A GB1602056A GB2219378A GB2219378A GB1602056A GB 1602056 A GB1602056 A GB 1602056A GB 2219378 A GB2219378 A GB 2219378A GB 2219378 A GB2219378 A GB 2219378A GB 1602056 A GB1602056 A GB 1602056A
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- circuit
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H47/00—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current
- H01H47/22—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current for supplying energising current for relay coil
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H1/00—Contacts
- H01H1/50—Means for increasing contact pressure, preventing vibration of contacts, holding contacts together after engagement, or biasing contacts to the open position
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- Relay Circuits (AREA)
- Keying Circuit Devices (AREA)
Description
(54) METHOD AND CIRCUIT ARRANGEMENT
FOR DAMPING CONTACT VIBRATIONS IN A
DRY-REED SWITCH
(71) We, ROBERT BOSCH Gmbll, a German company of 50, Postfach,
Stuttgart, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- The invention relates to a method of damping contact vibrations in a dry-reed switch having at least one springy, ferromagnetic contact blade, which is movable, under the influence of a magnetic field produced by means of an exciting current by an exciting winding, out of a position of rest into a closed position to close a switch contact, in which position it bears against a counter element, and a circuit arrangement for carrying out the method.
In dry-reed switches, as in many other mechanical switches, there is the risk of contact chatter when the switch contact is closed, particularly when a pulse with a steep leading edge is used to control a dry-reed switch, although, on the other hand, such a steep leading edge of the pulse supplied to the exciting winding is often necessary in order to obtain a defined moment of switching on.
Furthermore, there is an increased risk of contact chatter in dry-reed switches when the exciting winding is again controlled, shortly after the opening of the switch contact, to bring about a renewed closing of the switch contact. The contact blades of dry-reed switches the counter element is usually also constructed in the form of a ferromagnetic springy contact blade vibrate for a long time with a considerable amplitude after the opening of the switch contact, so that if the magnetic field becomes effective at a moment when the contact blade is just moving in the direction of the closed position, as a result of the preceding actuation of the switch, a particularly violent contact chatter can be triggered off. During experiments on a mass-produced dry-reed switch, for example, it was found that the chatter vibrations on closing of the switch contact only died away after a period of about 1.2 ms and that, after the switching off of the exciting current, the contact blades executed such weakly damped vibrations that the contact spacing in the first period of this vibration was reduced to less than 10% of the spacing at rest and the amplitude of the subsequent vibrations even at the end of a pause lasting 20 ms between two switching cycles, still amounted to 25% of the spacing at rest.
The efforts hitherto known for the suppression of contact-chatter pulses did not apply to the suppression of the contactchatter pulses themselves, as the DT-OS 2 416 131 shows for example, but to the suppression of the harmful consequences'of such contact-chatter pulses on following circuit arrangements, particularly at the inputs of a flip-flop.
Starting from the prior art, it is the object of the invention to indicate a method and a circuit arrangement for the suppression of contact vibrations in dry-reed switches, with which it is possible effectively to prevent contact chatter in the dry-reed switch itself.
According to the present invention there is provided a method of damping contact vibrations in a dry-reed switch having at least one springy, ferromagnetic contact blade which is movable out of a position of rest into a closed position under the influence of a magnetic field produced by means of an exciting current through an exciting winding to close a switch contact, in which closed position it bears against a counter element, characterised in that, after acceleration of the contact blade towards the closed position, the magnetic field is attenuated so that the velocity of the contact blade on impingement on the counter element becomes substantially zero and/or that, after the opening of the switch contact, while the contact bade is moving resiliently back into its position of rest, the magnetic field is strengthened in such a manner that the velocity of the contact blade on first entering its position of rest, becomes substantially zero.
Thus, according to the invention, after the acceleration of the contact blade towards its closing position, the accelerating force acting on the contact blade is reduced possibly to zero in order to achieve that the contact blade bears gently against the counter element and does not show any tendency to spring back away from this again. Only then is the magnetic field built up again to such an extent that the switch contact is held in its closed position. In addition, or instead of this, according to the invention, after the opening of the switch contact, a magnetic field is again briefly built up which briefly brakes the contact blade or the two contact blades usually present, flying back into their position of rest to such an extent that substantially no overswing occurs with respect to its position of rest.
It will be understood that when both means are used side by side a particularly high security against contact chatter is achieved. On the other hand, in man cases, it may already be sufficient if, alter the opening of the switch contact, a stillstand of the contact blade or blades in their position of rest is achieved very rapidly, because then, on renewed closing of the switch contact even after a relatively short interval in switching, the presence of defined initial conditions is assured.
It is an advantage if, when controlling the exciting winding with a current pulse with relatively steep edges the current pulse is interrupted after the expiration of a first predetermined interval of time after its beginning for the duration of a second predetermined interval of time and the durations of the two intervals are adapted to one another and to the operational parameters of the relay in such a manner that the relative velocity between contact blade and counter element at the moment of their impact becomes substantially zero, and/or that after a third predetermined interval of time after the end of the current pulse, a follow-up pulse is applied to the exciting winding for the duration of a fourth predetermined interval of time and the durations of the two intervals are adapted to one another and to the operational parameters of the relay in such a manner that the velocity of the contact blade after the opening of the switch contact, when it first enters its position of rest, becomes substantially zero. This modification of the method according to the invention is particularly advantageous in connection with digital electronic switching circuits.
For carrying out the method according to the invention, a circuit arrangement has proved advantageous which is characterised in that a controllable semiconductor is provided, the break of which is connected in series with the exciting winding of the dry-reed switch and the control electrode of which can be controlled by a control voltage, through the circuit combination of a high-pass filter and low-pass filter, the high-pass filter and the low-pass filter preferably being constructed in the form of simple RC networks. When the exciting winding of the dry-reed switch is controlled by a current pulse with relatively steep edges, a circuit arrangement has proved advantageous which is characterised in that a first switching circuit is provided with an input to which a control pulse can be supplied to release a current pulse for the exciting winding, that two monostable trigger circuits connected in series are connected to the input, of which the first can be triggered by the leading edge of the control pulse and supplies an output pulse the duration of which is equal to the duration of the first interval of time, and of which the second can be triggered by the trailing edge of the output pulse of the first monostable trigger circuit and supplies an output pulse, the duration of which is equal to the second predetermined interval of time, and that a logic circuit is provided at the output of the first switching circuit, by means of which the control pulse at the output of the first switching circuit can be suppressed for the duration of the output pulse of the second monostable trigger circuit and/or that a second switching circuit is provided with an input for the application of the control pulse and with two monostable trigger circuits connected in series behind the input, namely a third trigger circuit and a fourth trigger circuit, of which the third can be triggered by the trailing edge of the control pulse and supplies an output pulse, the duration of which is equal to the duration of the third interval of time, and of which the fourth can be triggered by the trailing edge of the output pulse of the third trigger circuit and supplies an output pulse, the duration of which is equal to the fourth Predetermined interval of time, and that a logic circuit is provided at the output of the second switching circuit by means of which logic circuit the control pulse and the output signal of the fourth monostable trigger circuit can be switched through to the output of the second switching circuit, and if the first and second switching circuits are used simultaneously, the outputs of these two switching circuits are connected to the two inputs of an OR circuit, the output of which is connected to the exciting winding of the dry-reed switch.
Further details and advantages of the invention are explained in more detail below with reference to the drawing.
Figures 1 aid are a diagrammatic illustration to explain the course in time of the movement of the contact blade and of the exciting current in a dry-reed switch wired in the usual manner and a dry-reed switch according to the invention;
Figure 2 shows a first preferred form of embodiment of a circuit arrangement according to the invention to suppress the contact chatter on closing the switch contact of a dry-reed switch;
Figure 3 shows a second preferred form of embodiment of a circuit arrangement according to the invention for the suppression of vibrations of a contact blade of a dry-reed switch on the opening of the switch contact thereof;
Figure 4 shows a third preferred form of embodiment of a circuit arrangement according to the invention, and
Figure 5 shows a diagrammatic illustration of the course of the exciting current in a circuit arrangement as shown in
Figure 5.
When a current pulse with relatively steep edges or substantially vertical edges is supplied in the usual manner to the exciting winding of a dry-reed switch, as illustrated in Figure 1 b, then, - as shown diagrammatically in Figure la, after the closing of the switch contact of the dry-reed switch, contact chatter occurs and after the opening thereof, a prolonged vibration of its at least one contact blade about its position of rest, the maximum amplitude of vibration which occurs being considerable which leads to the difficulties explained at the beginning.
In Figure 1, the abscissa is the time axis for the time t, while the exciting current I and the amplitude A of a contact blade, in relation to its position of rest are plotted on the ordinates.
On the other hand, if the energizing current is interrupted after a first interval of time 1, which lasts from the time to to the time tl, in accordance with the invention, as shown in Figure Id, for the duration of a second interval of time 2, which lasts from the time t1 to the time t2, then, with correct dimensioning of the intervals of time 1 and 2, the contact blade runs so slowly into its closed position that no contact chatter occurs. Furthermore, if, in accordance with
Figure Id, after a third interval of time 3 after the end of the current pulse, which lasts from a time t3 to a time t4, a follow-up pulse is produced during a fouth interval of time 4, which lasts from a time t4 to a time t5, then a vibration of the contact blade about its position of rest can be avoided as Figure Ic shows.
The course of the exciting current for the exciting winding of the dry-reed switch, shown in Figure 1d can be achieved by a combination of the circuit arrangements of
Figures 2 and 3, the circuit arrangement of
Figure 2 serving to suppress the contact chatter, while the circuit arrangement of
Figure 3 serves to prevent a vibration of the contact blade about its position of rest.
In detail, the circuit arrangement of
Figure 2 has an input 10 to which a control pulse, indicated diagrammatically with steep edges can be supplied. Connected in series behind the input 10 are a first monostable trigger circuit 12, a second monostable trigger circuit 14, an inverter 16 and the one input of AND circuit 18. The second input of the AND circuit 18 is directly connected to the input 10. The output of the AND circuit 18 is connected to the exciting winding 22 of a dry-reed switch through an amplifier 20.
The first monostable trigger circuit 12 is triggered by the positive leading edge of the control pulse and then produces a pulse, the duration of which corresponds to the first interval of time 1 and can be adjusted by appropriate external wiring of the first trigger circuit 12, for example by means of a resistor 13. The trailing edge of the output pulse of the first monostable trigger circuit 12 triggers the second monostable trigger circuit 14 which then produces an output pulse, the duration of which corresponds to the second interval of time 2 and is adjustable, for example, by means of a resistor 15. The output pulse of the second monostable trigger circuit 14 is inverted by the inverter 16 and supplied to the one input of the AND circuit 18 to the second input of which the control pulse is applied directly.
At the output of the AND circuit 18 or at the output of the amplifier 20 following it, there thus results the course of the exciting current for the exciting winding indicated in
Figure 2, namely a pulse train consisting of a preliminary pulse which is followed after a defined pulse, a contact blade of the dryreed switch is accelerated by the exciting winding 22 out of its position of rest towards its closed position, the duration of the preliminary pulse and the following interval being so dimensioned that the contact blade only impinges on its associated counter element with minimum velocity. If the main pulse then begins at the moment of this impact, then the switch contact of the dry-reed switch remains closed without any contact chatter occurring. On the other hand, vibration of the contact blades of the dry-reed switch about their position of rest after the opening of the switch contact, that is to say at the end of the main pulse, cannot be prevented by the circuit arrangement shown in Figure 2. These vibrations are suppressed, on the other hand, by means of the circuit arrangement shown in Figure 3.
As Figure 3 shows, connected to the input
10 of the circuit arrangement shown there is
the series connection of a third monostable trigger circuit 24, a fourth monostable trigger circuit 26 and the one input of an OR circuit 28, the output of which is connected to an exciting winding 22 of a dry-reed switch through an amplifier 20.
The third monostable trigger circuit 24 is triggered by the trailing edge of the control pulse and then produces an output pulse, the duration of which corresponds to the third interval of time 3 and can be adjusted, for example, by means of a resistor 23. The trailing edge of the output pulse of the third monostable trigger circuit 24 triggers the fourth monostable trigger circuit 26 which then produces, at its output or at the one input of the OR circuit 28, an output pulse, the duration of which corresponds to the fourth interval of time and can be adjusted, for example, by means of a resistor 25. The second input of the OR circuit 28 is directly connected to the input 10 of the circuit arrangement shown in Figure 3. Thus at the output of the OR circuit 28 or at the output of the amplifier 20 and hence at the exciting winding 22, there results the current course indicated there with a main pulse only partially illustrated which is followed after an interval by a follow-up pulse. The contact blade flying back into its position of rest is braked by this follow-up so that, with a suitable selection of the interval and of the duration of the follow-up pulse and/or the height of this, on travelling into its position of rest for the first time, it only has a minimum velocity and so comes completely to rest very quickly. Thus assurance is provided that on a renewed switching on of the dry-reed switch, the contact blade is in a defined initial position, namely in its position of rest, even if the renewed switching on is effected very shortly after the previous switching off.
The above description of Figures 2 and 3 shows that a suppression of the contact chatter and a prevention of prolonged free vibration of the contact blade are achieved if the circuit arrangements of Figure 2 and.
Figure 3 are combined as the first and second switching circuit of a combined circuit arrangement, by connecting the inputs 10, which for this reason have been given the same reference numerals, directly to one another, and by connecting the outputs of the AND circuit 18 and the output of the OR circuit 28 to the two inputs of a further OR circuit, the output of which is then again connected to the amplifier 20.
In this case, a course of the exciting current results as shown in Figure Id, only one amplifier 20 being needed, for which reason this amplifier is likewise designated by the same reference numeral in Figures 2 and 3.
Whereas Figures 2 and 3 show digital variants of circuit arrangements according to the invention, Figure 4 illustrates a similar form of embodiment of a circuit arrangement according to the invention by means of which both the contact chatter and the vibration of the contact blade about its position of rest after the opening of the switch contact of a dry-reed switch can be least largely avoided.
In detail, in the circuit arrangement shown in Figure 4, an input 30 is provided to which a control pulse indicated diagrammatically can be supplied. The input 30 is connected, through a capacitor Cl, to the base of a transistor 32, the collector of which is connected to suPply voltage (+) and the emitter of which is connected to the exciting winding 22 of a dry-reed switch, the other end of which is at reference potential. The input 30 is further connected to reference potential through a series connection of a potentiometer P2 and a further capacitor C2. In addition, the common junction point of the potentiometer P2 and of the capacitor C2 is connected through a further potentiometer P1 to the base connection of the capacitor
C1. The arrangement described of the capacitors C1, C2 and the potentiometers Pg, P2 represents the combination of a high-pass filter and a low-pass filter, the capacitor C, and the potentiometer P1 forming an RC network with a short time constant while the capacitor C2 and the potentiometer P2 form an RC network with a long time constant.
The circuit arrangement shown in Figure 4 works as follows: On the arrival of the leading edge of the control pulse, that is to say when the voltage at the input 30 rises from "0" to "1", a displacement current results through the capacitor C1 which immediately controls the transistor 32 so as to be conducting; thus the circuit arrangement behaves like a high-pass filter or like a differentiating network.
Then the first capacitor C1 begins to charge and finally reaches a state of charge the result of which is that of the base voltage of the transistor 32 drops towards zero. Thus the transistor 32 is at least largely cut off.
When this blocking state occurs, the second capacitor C2 has charged to a certain voltage through the potentiometer P2 and finally controls the transistor 32 so that it becomes conducting again. This state is maintained until the control pulse ends, that is to say until the potential at the input 30 drops from "1" to "0". At this moment, the first capacitor C1 is now charged by the second capacitor C2 through the potentiometer P1 so that the transistor 32, which at first is at least substantially nonconducting at the end of the control pulse, again becomes briefly conducting, until the second capacitor C2 has discharged sufficiently through the second potentiometer P2- The above description of the operation of the circuit arrangement of Figure 4 shows that, with this, a course of the exciting current I the exciting winding 22 can be achieved as illustrated diagrammatically over the time tin Figure 5.
Fundamentally, there is also the possibility of constructing a circuit arrangement according to the invention so that the exciting-current signal, which may have to be amplified, has, at its output, at least a passage through zero, which leads to a corresponding attenuation of the magnetic field produced by the exciting winding of the dry-reed switch, which is possible because the direction of current in the exciting winding and the direction of the magnetic field do not play any part in the switching operation. On the other hand, such exciting-current signals with passages through zero may, in certain circumstances, be easier to realize than an exciting-current signal which always has the same polarity and only drops once or twice substantially or completely to zero.
WHAT WE CLAIM IS:
1. A method of damping contact vibrations in a dry-reed switch having at least one springy, ferromagnetic contact blade which is movable out of a position of rest into a closed position under the influence of a magnetic field produced by means of an exciting current through an exciting winding to close a switch contact, in which closed position it bears against a counter element, characterised in that, after acceleration of the contact blade towards the closed position, the magnetic field is attenuated so that the velocity of the contact blade on impingement on the counter element becomes substantially zero and/or that, after the opening of the switch contact, while the contact blade is moving resiliently back into its position of rest, the magnetic field is strengthened in such a manner that the velocity of the contact blade on first entering its position of rest, becomes substantially zero.
2. A method of damping contact vibrations in a dry-reed switch, the exciting winding of which is supplied with a current pulse having relatively steep edges, as claimed in Claim 1, characterised in that, after the expiration of a first predetermined interval of time (1) after its beginning, the current pulse is interrupted for the duration of a second predetermined interval of time (2) and the durations of the two intervals of time (1, 2) are adapted to one another and to the operational parameters of the relay in such a manner that the relative velocity between contact blade and counter element at the moment of their impact becomes substantially zero and/or that, after a third predetermined interval of time (3) after the end of the current pulse, a follow-up pulse is applied to the exciting winding (22) for the duration of a fourth predetermined interval of time (4) and the durations of the two intervals (3, 4) are adapted to one another and to the operational parameters of the relay so that the velocity of the contact blade, after the opening of the switch contact, on first entering its position of rest, becomes substantially zero.
3. A circuit arrangement for carrying out the method as claimed in Claim 1, characterised in that a controllable semiconductor (32) is provided, the switching section of which is connected in series with the exciting winding (22) of the dry-reed switch and the control electrode of which can be controlled by a control voltage through the circuit combination of a high-pass filter and a low-pass filter.
4. A circuit arrangement as claimed in
Claim 3, characterised in that the high-pass filter and the low-pass filter are constructed in the form of simple RC networks (P1Cl; P2,
5. A circuit arrangement for carrying out the method as claimed in Claim 2, characterised in that a first switching circuit (Figure 2) is provided with an input (10) to which a control pulse can be supplied to release a current pulse for the exciting winding (22), that two series-connected monostable trigger circuits (12, 14) are connected to the input (10), of which the first (12) can be triggered by the leading edge of the control pulse and supplies an output pulse the duration of which is equal to the duration of the first interval of time (1), and of which the second (14) can be triggered by the trailing edge of the output pulse of the first monostable trigger circuit (12) and supplies an output pulse, the duration of which is equal to the second predetermined interval of time (2), and that logic circuit (18) is provided at the output of the first switching circuit (Figure 2) by means of which the control pulse at the output of the first switching circuit can be suppressed for the duration of the output pulse of the second monostable trigger circuit (14), and/or that a second switching circuit (Figure 3) is provided, with an input (10) for the application of the control pulse and with two monostable trigger circuits (24, 26) connected in series behind the
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (5)
1. A method of damping contact vibrations in a dry-reed switch having at least one springy, ferromagnetic contact blade which is movable out of a position of rest into a closed position under the influence of a magnetic field produced by means of an exciting current through an exciting winding to close a switch contact, in which closed position it bears against a counter element, characterised in that, after acceleration of the contact blade towards the closed position, the magnetic field is attenuated so that the velocity of the contact blade on impingement on the counter element becomes substantially zero and/or that, after the opening of the switch contact, while the contact blade is moving resiliently back into its position of rest, the magnetic field is strengthened in such a manner that the velocity of the contact blade on first entering its position of rest, becomes substantially zero.
2. A method of damping contact vibrations in a dry-reed switch, the exciting winding of which is supplied with a current pulse having relatively steep edges, as claimed in Claim 1, characterised in that, after the expiration of a first predetermined interval of time (1) after its beginning, the current pulse is interrupted for the duration of a second predetermined interval of time (2) and the durations of the two intervals of time (1, 2) are adapted to one another and to the operational parameters of the relay in such a manner that the relative velocity between contact blade and counter element at the moment of their impact becomes substantially zero and/or that, after a third predetermined interval of time (3) after the end of the current pulse, a follow-up pulse is applied to the exciting winding (22) for the duration of a fourth predetermined interval of time (4) and the durations of the two intervals (3, 4) are adapted to one another and to the operational parameters of the relay so that the velocity of the contact blade, after the opening of the switch contact, on first entering its position of rest, becomes substantially zero.
3. A circuit arrangement for carrying out the method as claimed in Claim 1, characterised in that a controllable semiconductor (32) is provided, the switching section of which is connected in series with the exciting winding (22) of the dry-reed switch and the control electrode of which can be controlled by a control voltage through the circuit combination of a high-pass filter and a low-pass filter.
4. A circuit arrangement as claimed in
Claim 3, characterised in that the high-pass filter and the low-pass filter are constructed in the form of simple RC networks (P1Cl; P2,
5. A circuit arrangement for carrying out the method as claimed in Claim 2, characterised in that a first switching circuit (Figure 2) is provided with an input (10) to which a control pulse can be supplied to release a current pulse for the exciting winding (22), that two series-connected monostable trigger circuits (12, 14) are connected to the input (10), of which the first (12) can be triggered by the leading edge of the control pulse and supplies an output pulse the duration of which is equal to the duration of the first interval of time (1), and of which the second (14) can be triggered by the trailing edge of the output pulse of the first monostable trigger circuit (12) and supplies an output pulse, the duration of which is equal to the second predetermined interval of time (2), and that logic circuit (18) is provided at the output of the first switching circuit (Figure 2) by means of which the control pulse at the output of the first switching circuit can be suppressed for the duration of the output pulse of the second monostable trigger circuit (14), and/or that a second switching circuit (Figure 3) is provided, with an input (10) for the application of the control pulse and with two monostable trigger circuits (24, 26) connected in series behind the
input, namely a third trigger circuit (24) and a fourth trigger circuit (26), of which the third (24) can be triggered by the trailing edge of the control pulse and supplies an output pulse the duration of which is equal to the duration of the third interval of time (3) and of which the fourth (26) can be triggered by the trailing edge of the output pulse of the third trigger circuit (24) and supplies an output pulse, the duration of which is equal to the fourth predetermined interval of time (4), and that a logic circuit (28) is provided at the output of the second switching circuit (Figure 3), by means of which logic circuit the control pulse and the output signal of the fourth monostable trigger circuit (26) can be switched through to the output of the second switching circuit (Figure 3), and if the first and second switching circuits are used simultaneously, the outputs of these two switching circuits are connected to the two inputs of an OR circuit, the output of which is connected to the exciting winding (22) of the dry-reed switch.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19782801582 DE2801582C2 (en) | 1978-01-14 | 1978-01-14 | Method and circuit arrangement for damping contact vibrations in a reed switch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1602056A true GB1602056A (en) | 1981-11-04 |
Family
ID=6029535
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB2219378A Expired GB1602056A (en) | 1978-01-14 | 1978-05-24 | Method and circuit arrangement for damping contact vibrations in a dry-reed switch |
Country Status (2)
| Country | Link |
|---|---|
| DE (1) | DE2801582C2 (en) |
| GB (1) | GB1602056A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108390667A (en) * | 2018-04-30 | 2018-08-10 | 魏展生 | A kind of indicating circuit of light-operated automatic conversion Push And Release |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB9110863D0 (en) * | 1991-05-20 | 1991-07-10 | Inertia Switch Ltd | Electric switch |
-
1978
- 1978-01-14 DE DE19782801582 patent/DE2801582C2/en not_active Expired
- 1978-05-24 GB GB2219378A patent/GB1602056A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108390667A (en) * | 2018-04-30 | 2018-08-10 | 魏展生 | A kind of indicating circuit of light-operated automatic conversion Push And Release |
| CN108390667B (en) * | 2018-04-30 | 2024-06-04 | 魏展生 | Indicating circuit for light-operated automatic switching on/off |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2801582C2 (en) | 1985-03-28 |
| DE2801582A1 (en) | 1979-07-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PCNP | Patent ceased through non-payment of renewal fee |