CA1109555A - Timed electric switch - Google Patents
Timed electric switchInfo
- Publication number
- CA1109555A CA1109555A CA369,340A CA369340A CA1109555A CA 1109555 A CA1109555 A CA 1109555A CA 369340 A CA369340 A CA 369340A CA 1109555 A CA1109555 A CA 1109555A
- Authority
- CA
- Canada
- Prior art keywords
- contacts
- timed
- switch
- elapsed time
- timer
- 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
Classifications
-
- G—PHYSICS
- G04—HOROLOGY
- G04F—TIME-INTERVAL MEASURING
- G04F1/00—Apparatus which can be set and started to measure-off predetermined or adjustably-fixed time intervals without driving mechanisms, e.g. egg timers
- G04F1/005—Apparatus which can be set and started to measure-off predetermined or adjustably-fixed time intervals without driving mechanisms, e.g. egg timers using electronic timing, e.g. counting means
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H43/00—Time or time-programme switches providing a choice of time-intervals for executing one or more switching actions and automatically terminating their operations after the programme is completed
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H3/00—Mechanisms for operating contacts
- H01H3/32—Driving mechanisms, i.e. for transmitting driving force to the contacts
- H01H3/50—Driving mechanisms, i.e. for transmitting driving force to the contacts with indexing or locating means, e.g. indexing by ball and spring
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H3/00—Mechanisms for operating contacts
- H01H3/32—Driving mechanisms, i.e. for transmitting driving force to the contacts
- H01H3/50—Driving mechanisms, i.e. for transmitting driving force to the contacts with indexing or locating means, e.g. indexing by ball and spring
- H01H3/503—Driving mechanisms, i.e. for transmitting driving force to the contacts with indexing or locating means, e.g. indexing by ball and spring making use of electromagnets
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Lighting Device Outwards From Vehicle And Optical Signal (AREA)
Abstract
ABSTRACT
A timed electric switch in a housing preferably for direct current loads such as for heating elements in vehicle windows, in which manually closable contacts supply current to the load and also to a timing circuit which may be digital, which completes a circuit through a holding solenoid for the contacts. After a predetermined time or count has been achieved in the timing circuit, the current supply through the holding solenoid, is interrupted thereby releasing the con-tacts. Provision is also made for allowing the second and subsequent timing periods to differ from the first timing period such as by independently supplying a potential to the timing circuit, such as through the vehicle ignition switch.
Reset of the timing circuit to produce the initial timing period once again is then effected by switch off and re-opera-tion of the ignition switch. An illuminated indication is provided, preferably by a light emitting diode, which operates when the switch is operated. Provision is made for altering the length of the second and subsequent time periods with respect to the initial timing period.
A timed electric switch in a housing preferably for direct current loads such as for heating elements in vehicle windows, in which manually closable contacts supply current to the load and also to a timing circuit which may be digital, which completes a circuit through a holding solenoid for the contacts. After a predetermined time or count has been achieved in the timing circuit, the current supply through the holding solenoid, is interrupted thereby releasing the con-tacts. Provision is also made for allowing the second and subsequent timing periods to differ from the first timing period such as by independently supplying a potential to the timing circuit, such as through the vehicle ignition switch.
Reset of the timing circuit to produce the initial timing period once again is then effected by switch off and re-opera-tion of the ignition switch. An illuminated indication is provided, preferably by a light emitting diode, which operates when the switch is operated. Provision is made for altering the length of the second and subsequent time periods with respect to the initial timing period.
Description
5~i This invention relates to timed swit ch ap~aralus Ecr electric loads.
Timed switches find particular application in the control of heavy direet eurrent applied to window heaters in vehicles, particularly backlite heaters in automobiles and truc}:s.
It has become increasingly apparent over the last ~ew years that sources of energy are not inexhaustible, that fuels ~or motor vehicles continue to increase in price, and that all possible savings in operation costs of the vehicle are to advantage. Further, backlite heaters intended for defrosting purposes draw heavy currents, in some instances, o~ the order of 40 amps, or even more where the trend is to larger glass areas, from a 12-volt car battery supply. At those times when headlights and in-car heaters are also switched on there is heavy competition for the available output from the battery and alternator. If the backlite has merely a siml-le on-off switch and the heater is used continuously in sueh conditions, particular]y when the ear -~ is in stop-and-go traffie, the battery ean be run flat.
I have diselosed a backlite timer in my prior Canadian Patent 868,62g issued 13 April, 1971 directed to a long interval timing device to which referenee may be made for background. The corresponding ~.S. Pa-tent is 3,571,665 issued 23 Mareh, 197l.
That timer ensures that the heater is not on continuously hy providiny an interval of operation for defrosting and which can vary to some extent with environmental temperature eonditions.
To eonform with the laws requiring continue(l improvina gasoline consumption effieieney there is also a steady accent in the automobile manufact-uring trade on the need to reduce weight. Apparatus here disclosed may replace a switeh, pilot-light, ~irinq harness, connectors, relay and timing circuitry current.ly employed in timed defrost orranqements, by a .sin~Jle package having typieally one-third the weigilt of the assemblies now em~]oyed in the industry.
,~ , ' , - 1 _ :.
, `~ sss Considerable cost savings pe~ car c~n flow from lower initi~l cost and weight and space savin~s.
Another feature of one embodiment of inventive apparatus here described takes account of the fact that where initial defrosting may requlre the application of current for an interval of the order of 10 to 15 minutes before switch-off, subsequently the backlite he~ter may need to be reactivated one or more times ~or demisting purposes. The subsequ~nt periods may usefully be less than that of the first. With single period timers the intsrval chosen has to bs a compromise.
~n this present disclosure, an electrical time switching device i~
described which allows not only an initial period of operation, but also provides the opportunity of having shorter periods of operation for the second and subsequent actuations of the device, such as is beneficial for demisting purposes after initial defrost action.
It is also to advantage, and a device is so described, which in a multiple period timer, includes an automatic reset a~ter the automobile has been stopped, so that the next time the backlite heater is require~ the full initial tlming period of operation can be provided. A typica] period of operation would initially be 10 minutes with a 5-minute pariod in each subsequent operation. In some applications, second and subsequent periods of
Timed switches find particular application in the control of heavy direet eurrent applied to window heaters in vehicles, particularly backlite heaters in automobiles and truc}:s.
It has become increasingly apparent over the last ~ew years that sources of energy are not inexhaustible, that fuels ~or motor vehicles continue to increase in price, and that all possible savings in operation costs of the vehicle are to advantage. Further, backlite heaters intended for defrosting purposes draw heavy currents, in some instances, o~ the order of 40 amps, or even more where the trend is to larger glass areas, from a 12-volt car battery supply. At those times when headlights and in-car heaters are also switched on there is heavy competition for the available output from the battery and alternator. If the backlite has merely a siml-le on-off switch and the heater is used continuously in sueh conditions, particular]y when the ear -~ is in stop-and-go traffie, the battery ean be run flat.
I have diselosed a backlite timer in my prior Canadian Patent 868,62g issued 13 April, 1971 directed to a long interval timing device to which referenee may be made for background. The corresponding ~.S. Pa-tent is 3,571,665 issued 23 Mareh, 197l.
That timer ensures that the heater is not on continuously hy providiny an interval of operation for defrosting and which can vary to some extent with environmental temperature eonditions.
To eonform with the laws requiring continue(l improvina gasoline consumption effieieney there is also a steady accent in the automobile manufact-uring trade on the need to reduce weight. Apparatus here disclosed may replace a switeh, pilot-light, ~irinq harness, connectors, relay and timing circuitry current.ly employed in timed defrost orranqements, by a .sin~Jle package having typieally one-third the weigilt of the assemblies now em~]oyed in the industry.
,~ , ' , - 1 _ :.
, `~ sss Considerable cost savings pe~ car c~n flow from lower initi~l cost and weight and space savin~s.
Another feature of one embodiment of inventive apparatus here described takes account of the fact that where initial defrosting may requlre the application of current for an interval of the order of 10 to 15 minutes before switch-off, subsequently the backlite he~ter may need to be reactivated one or more times ~or demisting purposes. The subsequ~nt periods may usefully be less than that of the first. With single period timers the intsrval chosen has to bs a compromise.
~n this present disclosure, an electrical time switching device i~
described which allows not only an initial period of operation, but also provides the opportunity of having shorter periods of operation for the second and subsequent actuations of the device, such as is beneficial for demisting purposes after initial defrost action.
It is also to advantage, and a device is so described, which in a multiple period timer, includes an automatic reset a~ter the automobile has been stopped, so that the next time the backlite heater is require~ the full initial tlming period of operation can be provided. A typica] period of operation would initially be 10 minutes with a 5-minute pariod in each subsequent operation. In some applications, second and subsequent periods of
2.5 minutes would be satisfactory.
A8 will be further de9cribed herein, an energy efficient auto-matic ~implified timing device can be con~tructed wi~h manual actuatlon and override providing a positive "feel" to the operator and including a pilot-light indicator of essentially infinite liEe, all in a slng~e package. Prototypes of specific embodi~ents here described have been delivering currents o~ 50 amperes both reliably and without any e~cessive contact heating. It will be understood `
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`, . ', ` : ~, `~ ` `
, 5~5 ~hat the apparatus diacloged ig not limited to ope~ation of automobile backlite heaters but m~ be us2d in a wide var~ety of appl~c~tion~ both in automobiles and elsewhere where single or multiple timed operation~ may be required. Tho8e skilled in the art will appreciate thst the tlmer circuit-ry may be used with or without con~unction of electric load switching or as an independent timing mechanism when timing functions are required.
In accordance with the ~nvention there is pro~lded a timed swltch for an electric load comprising, a pair of contacts for xeries connection with said load, said load bein8 ac~uated upon closing of said contacts, manually a~tuable means for causing 3ald contact~ to mo~e to a closed condition, ` :
- holding means for holding said contacts in the closed condition and for relea9ing said contact~ to an opened condition, said holdlng means being actuated upon clo~ing of 3aid contacts, and meanR for controlling said holding means, ~aid controlli~g means .:
; including timer me~ns responsive upon a fir~t closing of said contacts for producing a timed output indica~ive of a flrst predeter~ined elapsed ~0 time, and mean~ for ~witchin~ said timer meanB upon product~on of 3ald timed output for permi~ting the production of a second timed ou~pu~ frDm said timer means corresponding to a second predetermined elap~ed tlme different from said flr~t predetermined elapsed tlme responsive upon a ~econd closlng of said contac~s subsequent to a~id first clo~ln~, aaid holdlng means relea~ing ~ald contacts to the opened condi~ion ln responYe :~ to ~aid timed output8 from 8ald timer means. The swi~ching mean~ m~y include a control electrode for the timer means with the second predeter-mined elapsed time being dependent upon potential supply to the control electrode. There may be power supply mean~ for the timer mean~
~ 3 ~' ' .
~ 9~iiSi5 with means for resetting the timer upon disconnection of and reconnection of the power supply means to the timer, with the resetting means returning the timer to a condition for producing an output indicative of the first predetermined elapsed ~ime. The timer means may include an oscillator, countermeans sensitive to the oscillator, initiation means for effecting counting of output from the oscillator upon closing of the contacts and logic means for reading ~he count and producing the timed outputs when the count reaches predetermined values. The first predetermined elapsed time may be longer in duration than the second. The load may be an electric load in a vehicle which has an ignition switch with the timer means being reset upon openlng and subsequent reclosing of the ignition switch. The manually actuable means may be pivotally mounted which when pivoted in a first direction mechanically moves the contacts to the closed condition and when pivoted in a second direction mechanically moves the contacts to opened condition. The load may comprise a window - heater in the vehicle.
Specific embodiments of the invention will now be described having reference to the accompanying drawings in which;
Figure 1 shows a side sectioned view of one embodiment of the complete timing switch package;
Figure 2 is a plan view of the device from above, and Figure 3 a-plan view from the device of figure l; and Figure 4 is a schematic circuit diagram of electronic circuitry associated with the timing function and employing a digital integrated circuit, With reference first to figurss 1 to 3, a casing 1 of a suitable plastic material, such as A.B.S., has pivoted to one end oE it on projecting stubs 2 (Figure 3)9 a manually rockable actuating cover 3.
At the other end of the housing 1 extending Erom a mounting plate 4 _ 4 _ . .
9s~
are electrical contact spades S for connection to wiring harness or other socket terminals (not shown). Spring ears 6 on the case 1 in conjunction with stop flanges 7 enable the package assembly to be snap mounted for instance in an automobile dashboard. Received in socket 9 of cover 3 is a stub 8 of an actuating arm 10. The arm 10 is pivoted on short shafts 8' coaxial with stubs 2 received in the housing 1, and is constructed as two downward depending sections 10' one behind the other in figure 1, straddled by a web 10". A spring 11 engages extensions on the arm 10 to effect .
.
.
`' ' ' .
', :
- 4a -a restoring action whenever the rockable cover :3 is displaced from the central position shown in figure 1. ~ second spring (not shown) behind spring 11 enga~es the arm 10 only when the,cover 3 is rocked to displace the arm anti-clockwise, thereby prbviding a greater resllient resistance to the cover 3 when the arm is ~, rotated anti-clockwise. This improves the balanced "feel" of the device as will be explained later, Mounted on the plate 4 is a relay yoke, coil and core assembly 15, a timing circuit board 16 and a spring,beryllium copper or phosphor bronze output contact post 17 connected to out-put spade contact 18. Beryllium copper alloys are preferred for the post ma-terial.
The relay assembly comprises yoke 20 containing coil and former assembly 21, moveable core 22 with an armature or "obturator"
23 of a suitable conductive spring material such as spring beryllium copper or phosphor bronze. The obturator carries a contact 25. By virtue o~ -the fact that the obturator 23 is fa~ten-ed at its bottom end by retention between yoke 20 and a magnetical-ly permeable end plate 26, downward movement of the core 22 causes contact 25 to move both in an outward and a downward direction and thus effects very efficient contact wiping action with the contact 30 mounted on post 17. The,particular way in which this kind of wipiny action and relay obturator structure produces very efficient contacting is described in my U.S. patents 4,003,011 issued 11 January, 1977 and 4,064,470 issued 20 December, 1977.
Further details of this particular structure will not be elaborated here.
A shoulder flange 31 extends from the upper end of core 22 where it is enyageable by the web 10" ~ocking o~ khe arm 10 in the clockwise direction shown in figure 1 causes the web to depress sho~ulder 31 pushing the core 22 illtO the ~ormer assembly 21 and cau-siny contact 25 to engage contact 30. When the core 22 is depressed fully into the former its lower end strikes .
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;55 the end plate 26 to complete the magnetic circult through the yoke 20, core 22 and end plate ~6. Since the winding 19 on,.
fo.rmer 21 has becorne energi~ed byS~lo~ing of contacts ~5 an~
30 (in a m~nner which will be explained later) the core snaps against the plate 26 and is held in that pOSi.tiOIl a~ter release of rockable cover 3 and return of the arm 10 to the position : . shown in figure 1. The closing of the magnetic circuit ensures solid holding of the relay core even in the presence of strong vibration.
When the core is to be released, rocking of cover 3 and arm 10 in a counterclockwlse direction cau~es the arm to engage the upper leg 35 on post 17. This action breaks contact ,between 25 and 30, removing current from the coil 19 on former 21, and allowing collapse of the flu~ in the yoke, core and end plate circuit lassisted by incidental air gaps between the yoke and the core a-t the upper end, and between the core and the end plate at the lower end) so -that the core moves , rapidly out of the former back to the position shown in figure 1 striking the web 10" on arm 10.
It can be seen that this arrangement produces a snap action sensible by the operator both upon actua-tion of the device and closing of the relay when core 22 strikes plate 26, and also upon manual release of the'relay by the hammering action of the shoulder.31 against the web 10". In order to balance the "feel" of the device generally, since the 'resilient resistance encountered by the arm 10 when moved in a clockwlse direction to force core 22 into former 21 is sontewhat greater than that encountered whe~ the arm 10 is rocked against leg 35 to open contacts 25 and 30, the clockwise rotating 'action of the second spring 11 has been provided (~s previously detailed). This results in essentially all o~ t~le mallua].ly .
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applied rocking effort being applied to the s~lo~llder 31 when switching the device "ON" but in -the manually applied effort,.
being resisted ~y the springs ll (and leg 35) when the device is manually switched "OFF".
~ n indicator light 40, preferably a light emitting diode,is ~rovided in the upper end of casing 1, directed -to cause its light to fall on a window or lens 41 mounted in the rockable cover 3, to provide an indication to the operator whenever the device has been actuated and contacts 25 and 30 are 10 in closed position.
The schematic diagram of figure 4 illustrates the contacts 25 and 30, the light emittiny diode 40, coil l9 for core 22, and the terminal 50 connected to the ~ackli-te load. Input terminal 18 provides i.nput battery +ve 53 to contact 30, and to ignition switch 80, which is in turn connected to input termi~ial 51. Battery -ve (not shown) is connected to ground which is applied to input terminal 52.
Referring in more detail to ~igure 4, there is in,cluded an integrated circuit package 55 which embodies a power supply ~ 56, an oscillator 57, a counter 58, an output logic control 59 ,and an output stage 60. ~'erminals provided on this package 5S
are ground 61, oscillator input terminals 62 and 63, power supply input 64, initiating inpu-t 65, outpu-t logic time select 66 and coll activate terminal 67. Battery input at terminal 18 is applied to contact 30, and when the device is m~.nually actuated to close contact 25 against contact 30, the battery is then applied to tèrminal 50 and the backli-te loa~ 70. Connected to the lead from contact 25 to terminal 50 are one side of ' resistor 75, Gne side of relay coil 19, and a series connected resistor 76 and light emitting diode 40,. whose other side i5 returned to ground. Thus the application of the ~attery potential to contact 25 also applies an initiating vol-Lage to .
~109~i5~
-~ input 65, and also illuminates the cli.ode ~0. 'l'he voltage applied to relay coil 19 causes a current t~, [lo~ thro-lgh this coil ~a ~e~.~in~l 67 and -thence to ground through output s-tag.e 60 and terminals 61 and 52. This current p.rovides sufficient magnetic flux in the relay yoke assembly, core and end plate to hold the core at its inner pOSitiOIl, although the current is not su~ficien~ itself to pull in the core in the absence of the manual actuation provided by the engagement of arm 10 on the shoulcler 31.
Because only a small current is needed for holding purposes the winding 19 is constructed with the characteristics of a holding coil, rather than the much heavier characteristics needed for a pull-in winding.
It can be seen tha-t the closing of the car ignition switch 80 has also applied battery potential to terminal 51 which is fed through resistor 81 to power supply input 64 Protection agalnst transients is provided by ca~acitor 78 between terminal 65 and ground, and by capacitor 82~between :
terminal 64 and ground. The application of the initiating voltage at 65 switches on the oscillatorand tl~c output stage 6~. Thc oscillator is basically a relaxation ci.r,cuit whose timing is effected by resistor 83 between terminals 62 and 63 and capacitor 84 between terminal 63 and ground. ~ typical frequency of oscillation is 3.4 hertz and this frecluency is applied to the counter 58. Typically the counter would allow counting to 2,048 ~which corresponds to a lO~minute period).
The counter is read by the output logic 59, and when the total of 2,048 is achieved, the logic 59 triggers the output stage 60, which cuts off, interrupting the current .throucJh coil 19 and causing the core 22 to drop out. The zener di.ode 77 limits the voltage impulse appearing on terminal 67 due to the inductive effect of coil 19. The drop out of the core opens .
a - ~ . , the contacts 30, 25 removiny the power supply to the backlite load, to the light emitting diode 40, and to the input 65. .
The ignition switch 80 remains closed however, so that the power supply 56 is s-till actuated, -thereby retaining output logic 59 in a condition sensitive to the fact thak it has produced an output following an initial count by counter 58.
If now the timer is actuated a secon~ time by an operator again closing contacts 30, 25, applyincJ a new - initiating input to terminal 65, the oscillator will once again be switched on and the counter 58 set in action. This time however as the output logic 59 reads the counter, it produces a signal to the output stage 60 after a count of only 1,024 is reached. This time corresponds to 5 minutes, and therefore the contacts 30, 25 are opened after a 5-minute period. As theoutput logic control 59 continues to be sensitive to the fact that an output has been produced, subse~uent initiations of the device by closing contacts 30 and 25 will each time result in the 5-minute timing period. ~hen iynition switch 80 is opened,the input to power supply terminal 64 is removed and the output logic 59 will also be deactivated. Any su~sequent closin~ of ignition switch 80 will return the logic 59 to its initial state and will result in an initial timin~ OUtpllt only after a count of 2,0~8 has been achieved.
The output logic 59 is provided with the time select terminal 66, which allows for different functions of the output logic control 5~ dependent upon the voltage applied to terminal 66. If pin 66 is connected to ground 61 as illustrated in figure 4, then, a5~previously described,the first -timing interval will allow for a count of 2,048 (10 minutes) whereas the subsequent counts will be 1,024 (5 minutes). If however pin 66 is connected to the positive voltage on pin 6~, the initial ~9~ . .
:
~9~5 count will, as before, be 2,048, but suhsequ~nt counts will be 512 (or 2.5 minutes). If terminal 66 is le~t unconnected, there is no ehange in r~sponse to. ~he eoun~er between the first and any subsequent timer aetuations.
It can be seen therefore that consi~erable flexibility is provided for variations in timinc3 period between an initial time out and subsequent timings, as may be desired.
This kind o flexibility is not possible in an analog type of timer in whieh a capacitor is allowed to ch~r~e only onee 1~ during the timing eyele. By usin~ ~igital loc~ic with a counter, mueh higher oseillation frequenees are permissible resulting in very, very much smaller eapacitors with mueh lligher ~tolerance and lower temperature sensitivity. Such changes ; result in a much smaller unit, lower cost, lligher aceuraey and improved flexibility and performance.
With the new deviee, testing is greatly faeilitated beeause the oseillator ~UIIS at a eonstant speed and it ean be eheeked for aeeurate fre~ueney in a period of a few ~eeonds.
Using the eleetrolytie analog proeesses, matching of resistors to capacitors is necessary and testing requires the full run through of the timing period. Typieally, using an analog deviee, the timing eapaeitor had to be of the orcler of 220 ~;Ed with toleranees of -50~ to +100~. Using the much lower value eharging eapaeitor 84-of the present diselosure (approximately .01 ~fd~ and readily availa~le at elose tolerance, individual matehing is no longer required.
By the particular structure shown, manual cancellation or override can be effeete~ to s~-iteh the clreuit off any time ~ before its automatie time out since rernoval of potential from :, .
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. input 65, by manual openin~ of contacts 30, 25 wiil switch off the output stage 60. The removal of input at 65 also deactivates the oscillator 57, and subsequent reapplying and starting of the oscillator will cause the counter to start ~rom zero. The count necessary for actuating output from logic 59 will depend upon wllether or not the logic had already produced a rirst output, before the manual cancellation was effected.
Details of the counter 58 and.the output logic control 59 and the way in which the output logic can read the counter 58 differently between an initial and subsequent r operation will be apparent to those skilled in the art as welI
as the alteratlon of the reading dependent upon the application of ground, high voltage or open circuit to the -terminal 66.`
I2L integrated circuit logic -techniques are particularly suitable for the construction of the counter and output logic control.
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A8 will be further de9cribed herein, an energy efficient auto-matic ~implified timing device can be con~tructed wi~h manual actuatlon and override providing a positive "feel" to the operator and including a pilot-light indicator of essentially infinite liEe, all in a slng~e package. Prototypes of specific embodi~ents here described have been delivering currents o~ 50 amperes both reliably and without any e~cessive contact heating. It will be understood `
' ~D
`, . ', ` : ~, `~ ` `
, 5~5 ~hat the apparatus diacloged ig not limited to ope~ation of automobile backlite heaters but m~ be us2d in a wide var~ety of appl~c~tion~ both in automobiles and elsewhere where single or multiple timed operation~ may be required. Tho8e skilled in the art will appreciate thst the tlmer circuit-ry may be used with or without con~unction of electric load switching or as an independent timing mechanism when timing functions are required.
In accordance with the ~nvention there is pro~lded a timed swltch for an electric load comprising, a pair of contacts for xeries connection with said load, said load bein8 ac~uated upon closing of said contacts, manually a~tuable means for causing 3ald contact~ to mo~e to a closed condition, ` :
- holding means for holding said contacts in the closed condition and for relea9ing said contact~ to an opened condition, said holdlng means being actuated upon clo~ing of 3aid contacts, and meanR for controlling said holding means, ~aid controlli~g means .:
; including timer me~ns responsive upon a fir~t closing of said contacts for producing a timed output indica~ive of a flrst predeter~ined elapsed ~0 time, and mean~ for ~witchin~ said timer meanB upon product~on of 3ald timed output for permi~ting the production of a second timed ou~pu~ frDm said timer means corresponding to a second predetermined elap~ed tlme different from said flr~t predetermined elapsed tlme responsive upon a ~econd closlng of said contac~s subsequent to a~id first clo~ln~, aaid holdlng means relea~ing ~ald contacts to the opened condi~ion ln responYe :~ to ~aid timed output8 from 8ald timer means. The swi~ching mean~ m~y include a control electrode for the timer means with the second predeter-mined elapsed time being dependent upon potential supply to the control electrode. There may be power supply mean~ for the timer mean~
~ 3 ~' ' .
~ 9~iiSi5 with means for resetting the timer upon disconnection of and reconnection of the power supply means to the timer, with the resetting means returning the timer to a condition for producing an output indicative of the first predetermined elapsed ~ime. The timer means may include an oscillator, countermeans sensitive to the oscillator, initiation means for effecting counting of output from the oscillator upon closing of the contacts and logic means for reading ~he count and producing the timed outputs when the count reaches predetermined values. The first predetermined elapsed time may be longer in duration than the second. The load may be an electric load in a vehicle which has an ignition switch with the timer means being reset upon openlng and subsequent reclosing of the ignition switch. The manually actuable means may be pivotally mounted which when pivoted in a first direction mechanically moves the contacts to the closed condition and when pivoted in a second direction mechanically moves the contacts to opened condition. The load may comprise a window - heater in the vehicle.
Specific embodiments of the invention will now be described having reference to the accompanying drawings in which;
Figure 1 shows a side sectioned view of one embodiment of the complete timing switch package;
Figure 2 is a plan view of the device from above, and Figure 3 a-plan view from the device of figure l; and Figure 4 is a schematic circuit diagram of electronic circuitry associated with the timing function and employing a digital integrated circuit, With reference first to figurss 1 to 3, a casing 1 of a suitable plastic material, such as A.B.S., has pivoted to one end oE it on projecting stubs 2 (Figure 3)9 a manually rockable actuating cover 3.
At the other end of the housing 1 extending Erom a mounting plate 4 _ 4 _ . .
9s~
are electrical contact spades S for connection to wiring harness or other socket terminals (not shown). Spring ears 6 on the case 1 in conjunction with stop flanges 7 enable the package assembly to be snap mounted for instance in an automobile dashboard. Received in socket 9 of cover 3 is a stub 8 of an actuating arm 10. The arm 10 is pivoted on short shafts 8' coaxial with stubs 2 received in the housing 1, and is constructed as two downward depending sections 10' one behind the other in figure 1, straddled by a web 10". A spring 11 engages extensions on the arm 10 to effect .
.
.
`' ' ' .
', :
- 4a -a restoring action whenever the rockable cover :3 is displaced from the central position shown in figure 1. ~ second spring (not shown) behind spring 11 enga~es the arm 10 only when the,cover 3 is rocked to displace the arm anti-clockwise, thereby prbviding a greater resllient resistance to the cover 3 when the arm is ~, rotated anti-clockwise. This improves the balanced "feel" of the device as will be explained later, Mounted on the plate 4 is a relay yoke, coil and core assembly 15, a timing circuit board 16 and a spring,beryllium copper or phosphor bronze output contact post 17 connected to out-put spade contact 18. Beryllium copper alloys are preferred for the post ma-terial.
The relay assembly comprises yoke 20 containing coil and former assembly 21, moveable core 22 with an armature or "obturator"
23 of a suitable conductive spring material such as spring beryllium copper or phosphor bronze. The obturator carries a contact 25. By virtue o~ -the fact that the obturator 23 is fa~ten-ed at its bottom end by retention between yoke 20 and a magnetical-ly permeable end plate 26, downward movement of the core 22 causes contact 25 to move both in an outward and a downward direction and thus effects very efficient contact wiping action with the contact 30 mounted on post 17. The,particular way in which this kind of wipiny action and relay obturator structure produces very efficient contacting is described in my U.S. patents 4,003,011 issued 11 January, 1977 and 4,064,470 issued 20 December, 1977.
Further details of this particular structure will not be elaborated here.
A shoulder flange 31 extends from the upper end of core 22 where it is enyageable by the web 10" ~ocking o~ khe arm 10 in the clockwise direction shown in figure 1 causes the web to depress sho~ulder 31 pushing the core 22 illtO the ~ormer assembly 21 and cau-siny contact 25 to engage contact 30. When the core 22 is depressed fully into the former its lower end strikes .
.
. .
;55 the end plate 26 to complete the magnetic circult through the yoke 20, core 22 and end plate ~6. Since the winding 19 on,.
fo.rmer 21 has becorne energi~ed byS~lo~ing of contacts ~5 an~
30 (in a m~nner which will be explained later) the core snaps against the plate 26 and is held in that pOSi.tiOIl a~ter release of rockable cover 3 and return of the arm 10 to the position : . shown in figure 1. The closing of the magnetic circuit ensures solid holding of the relay core even in the presence of strong vibration.
When the core is to be released, rocking of cover 3 and arm 10 in a counterclockwlse direction cau~es the arm to engage the upper leg 35 on post 17. This action breaks contact ,between 25 and 30, removing current from the coil 19 on former 21, and allowing collapse of the flu~ in the yoke, core and end plate circuit lassisted by incidental air gaps between the yoke and the core a-t the upper end, and between the core and the end plate at the lower end) so -that the core moves , rapidly out of the former back to the position shown in figure 1 striking the web 10" on arm 10.
It can be seen that this arrangement produces a snap action sensible by the operator both upon actua-tion of the device and closing of the relay when core 22 strikes plate 26, and also upon manual release of the'relay by the hammering action of the shoulder.31 against the web 10". In order to balance the "feel" of the device generally, since the 'resilient resistance encountered by the arm 10 when moved in a clockwlse direction to force core 22 into former 21 is sontewhat greater than that encountered whe~ the arm 10 is rocked against leg 35 to open contacts 25 and 30, the clockwise rotating 'action of the second spring 11 has been provided (~s previously detailed). This results in essentially all o~ t~le mallua].ly .
~6--.
~ , , - , ' . . . .
~ r--55~
applied rocking effort being applied to the s~lo~llder 31 when switching the device "ON" but in -the manually applied effort,.
being resisted ~y the springs ll (and leg 35) when the device is manually switched "OFF".
~ n indicator light 40, preferably a light emitting diode,is ~rovided in the upper end of casing 1, directed -to cause its light to fall on a window or lens 41 mounted in the rockable cover 3, to provide an indication to the operator whenever the device has been actuated and contacts 25 and 30 are 10 in closed position.
The schematic diagram of figure 4 illustrates the contacts 25 and 30, the light emittiny diode 40, coil l9 for core 22, and the terminal 50 connected to the ~ackli-te load. Input terminal 18 provides i.nput battery +ve 53 to contact 30, and to ignition switch 80, which is in turn connected to input termi~ial 51. Battery -ve (not shown) is connected to ground which is applied to input terminal 52.
Referring in more detail to ~igure 4, there is in,cluded an integrated circuit package 55 which embodies a power supply ~ 56, an oscillator 57, a counter 58, an output logic control 59 ,and an output stage 60. ~'erminals provided on this package 5S
are ground 61, oscillator input terminals 62 and 63, power supply input 64, initiating inpu-t 65, outpu-t logic time select 66 and coll activate terminal 67. Battery input at terminal 18 is applied to contact 30, and when the device is m~.nually actuated to close contact 25 against contact 30, the battery is then applied to tèrminal 50 and the backli-te loa~ 70. Connected to the lead from contact 25 to terminal 50 are one side of ' resistor 75, Gne side of relay coil 19, and a series connected resistor 76 and light emitting diode 40,. whose other side i5 returned to ground. Thus the application of the ~attery potential to contact 25 also applies an initiating vol-Lage to .
~109~i5~
-~ input 65, and also illuminates the cli.ode ~0. 'l'he voltage applied to relay coil 19 causes a current t~, [lo~ thro-lgh this coil ~a ~e~.~in~l 67 and -thence to ground through output s-tag.e 60 and terminals 61 and 52. This current p.rovides sufficient magnetic flux in the relay yoke assembly, core and end plate to hold the core at its inner pOSitiOIl, although the current is not su~ficien~ itself to pull in the core in the absence of the manual actuation provided by the engagement of arm 10 on the shoulcler 31.
Because only a small current is needed for holding purposes the winding 19 is constructed with the characteristics of a holding coil, rather than the much heavier characteristics needed for a pull-in winding.
It can be seen tha-t the closing of the car ignition switch 80 has also applied battery potential to terminal 51 which is fed through resistor 81 to power supply input 64 Protection agalnst transients is provided by ca~acitor 78 between terminal 65 and ground, and by capacitor 82~between :
terminal 64 and ground. The application of the initiating voltage at 65 switches on the oscillatorand tl~c output stage 6~. Thc oscillator is basically a relaxation ci.r,cuit whose timing is effected by resistor 83 between terminals 62 and 63 and capacitor 84 between terminal 63 and ground. ~ typical frequency of oscillation is 3.4 hertz and this frecluency is applied to the counter 58. Typically the counter would allow counting to 2,048 ~which corresponds to a lO~minute period).
The counter is read by the output logic 59, and when the total of 2,048 is achieved, the logic 59 triggers the output stage 60, which cuts off, interrupting the current .throucJh coil 19 and causing the core 22 to drop out. The zener di.ode 77 limits the voltage impulse appearing on terminal 67 due to the inductive effect of coil 19. The drop out of the core opens .
a - ~ . , the contacts 30, 25 removiny the power supply to the backlite load, to the light emitting diode 40, and to the input 65. .
The ignition switch 80 remains closed however, so that the power supply 56 is s-till actuated, -thereby retaining output logic 59 in a condition sensitive to the fact thak it has produced an output following an initial count by counter 58.
If now the timer is actuated a secon~ time by an operator again closing contacts 30, 25, applyincJ a new - initiating input to terminal 65, the oscillator will once again be switched on and the counter 58 set in action. This time however as the output logic 59 reads the counter, it produces a signal to the output stage 60 after a count of only 1,024 is reached. This time corresponds to 5 minutes, and therefore the contacts 30, 25 are opened after a 5-minute period. As theoutput logic control 59 continues to be sensitive to the fact that an output has been produced, subse~uent initiations of the device by closing contacts 30 and 25 will each time result in the 5-minute timing period. ~hen iynition switch 80 is opened,the input to power supply terminal 64 is removed and the output logic 59 will also be deactivated. Any su~sequent closin~ of ignition switch 80 will return the logic 59 to its initial state and will result in an initial timin~ OUtpllt only after a count of 2,0~8 has been achieved.
The output logic 59 is provided with the time select terminal 66, which allows for different functions of the output logic control 5~ dependent upon the voltage applied to terminal 66. If pin 66 is connected to ground 61 as illustrated in figure 4, then, a5~previously described,the first -timing interval will allow for a count of 2,048 (10 minutes) whereas the subsequent counts will be 1,024 (5 minutes). If however pin 66 is connected to the positive voltage on pin 6~, the initial ~9~ . .
:
~9~5 count will, as before, be 2,048, but suhsequ~nt counts will be 512 (or 2.5 minutes). If terminal 66 is le~t unconnected, there is no ehange in r~sponse to. ~he eoun~er between the first and any subsequent timer aetuations.
It can be seen therefore that consi~erable flexibility is provided for variations in timinc3 period between an initial time out and subsequent timings, as may be desired.
This kind o flexibility is not possible in an analog type of timer in whieh a capacitor is allowed to ch~r~e only onee 1~ during the timing eyele. By usin~ ~igital loc~ic with a counter, mueh higher oseillation frequenees are permissible resulting in very, very much smaller eapacitors with mueh lligher ~tolerance and lower temperature sensitivity. Such changes ; result in a much smaller unit, lower cost, lligher aceuraey and improved flexibility and performance.
With the new deviee, testing is greatly faeilitated beeause the oseillator ~UIIS at a eonstant speed and it ean be eheeked for aeeurate fre~ueney in a period of a few ~eeonds.
Using the eleetrolytie analog proeesses, matching of resistors to capacitors is necessary and testing requires the full run through of the timing period. Typieally, using an analog deviee, the timing eapaeitor had to be of the orcler of 220 ~;Ed with toleranees of -50~ to +100~. Using the much lower value eharging eapaeitor 84-of the present diselosure (approximately .01 ~fd~ and readily availa~le at elose tolerance, individual matehing is no longer required.
By the particular structure shown, manual cancellation or override can be effeete~ to s~-iteh the clreuit off any time ~ before its automatie time out since rernoval of potential from :, .
.
.
` ~ 5$
. input 65, by manual openin~ of contacts 30, 25 wiil switch off the output stage 60. The removal of input at 65 also deactivates the oscillator 57, and subsequent reapplying and starting of the oscillator will cause the counter to start ~rom zero. The count necessary for actuating output from logic 59 will depend upon wllether or not the logic had already produced a rirst output, before the manual cancellation was effected.
Details of the counter 58 and.the output logic control 59 and the way in which the output logic can read the counter 58 differently between an initial and subsequent r operation will be apparent to those skilled in the art as welI
as the alteratlon of the reading dependent upon the application of ground, high voltage or open circuit to the -terminal 66.`
I2L integrated circuit logic -techniques are particularly suitable for the construction of the counter and output logic control.
' ' ' .
,...
.
.
.
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A timed switch for an electric load comprising, a pair of contacts for series connection with said load, said load being actuated upon closing of said contacts, manually actuable means for causing said contacts to move to a closed condition, holding means for holding said contacts in the closed condition and for releasing said contacts to an opened condition, said holding means being actuated upon closing of said contacts, and means for controlling said holding means, said controlling means including timer means responsive upon a first closing of said contacts for producing a timed output indicative of a first predetermined elapsed time, and means for switching said timer means upon production of said timed output for permitting the production of a second timed output from said timer means corresponding to a second predetermined elapsed time different from said first predetermined elapsed time responsive upon a second closing of said contacts subsequent to said first closing, said holding means releasing said contacts to the opened condition in response to said timed outputs from said timer means.
2. A timed switch as defined in claim 1 wherein said switching means includes a control electrode for said timer means and said second predetermined elapsed time is dependent upon potential supply to said control electrode.
3. A timed switch as defined in claim l including power supply means for said timer means and means for resetting said timer means upon disconnection of and reconnection of said power supply means to said timer means, said resetting means returning said timer means to a condition for producing said timed output indicative of said first predetermined elapsed time.
4. A timed switch as defined in claim 1 in which said timer means includes an oscillator, counter means sensitive to said oscillator, initiation means for effecting counting of output from said oscillator in response to the closing of said contacts and for establishing a count in said counter, and logic means connected to said counter for reading said count and producing said timed outputs when said count reaches predeter-mined values, said first predetermined elapsed time corresponding to a first predetermined value of said count and said second predetermined elapsed time corresponding to a second predetermined value of said count.
5. A timed switch as defined in claim 1 in which said first predetermined elapsed time is longer in duration than said second predetermined elapsed time.
6. A timed switch as defined in claim 3 in which said load comprises an electric load in a vehicle which vehicle includes an ignition switch, in which said power supply means for said timer means is energized through operation of said ignition switch, and in which said timer means is reset upon opening and subsequent reclosing of said ignition switch.
7. A timed switch as defined in claim 6 wherein said manually actuable means comprises pivotally mounted means which when pivoted in a first direction mechanically moves said contacts to the closed condition and which when pivoted in a second direction mechanically moves said contacts to the opened condition.
8. A timed switch as defined in claim 6 in which said load comprises a window heater in the vehicle.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7916957A FR2460538B1 (en) | 1978-04-21 | 1979-06-29 | TIMER SWITCHING DEVICE |
| DE19792928031 DE2928031A1 (en) | 1978-04-21 | 1979-07-11 | TIME-CONTROLLED SWITCH AND TIMER |
| CA369,340A CA1109555A (en) | 1978-04-21 | 1981-01-26 | Timed electric switch |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA301,690A CA1096028A (en) | 1978-04-21 | 1978-04-21 | Timed electric switch |
| FR7916957A FR2460538B1 (en) | 1978-04-21 | 1979-06-29 | TIMER SWITCHING DEVICE |
| DE19792928031 DE2928031A1 (en) | 1978-04-21 | 1979-07-11 | TIME-CONTROLLED SWITCH AND TIMER |
| CA369,340A CA1109555A (en) | 1978-04-21 | 1981-01-26 | Timed electric switch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1109555A true CA1109555A (en) | 1981-09-22 |
Family
ID=27426073
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA369,340A Expired CA1109555A (en) | 1978-04-21 | 1981-01-26 | Timed electric switch |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1109555A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0341416A2 (en) * | 1988-05-11 | 1989-11-15 | Wolfgang Dipl.-Ing. Priesemuth | Switching device |
-
1981
- 1981-01-26 CA CA369,340A patent/CA1109555A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0341416A2 (en) * | 1988-05-11 | 1989-11-15 | Wolfgang Dipl.-Ing. Priesemuth | Switching device |
| EP0341416A3 (en) * | 1988-05-11 | 1991-07-03 | Wolfgang Dipl.-Ing. Priesemuth | Switching device |
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