US 2337788 A
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Description (OCR text may contain errors)
Dec. 28, 1943. J. WHITE CONTROL SYSTEM FOR AUTOMOBILES Filed April 26, 1940 To SPEOOMETEI? CAELE INVENTOR M m MWM% 4.; ATToRNl-zw Patented Dec. 28, 1943 CONTROL SYSTEM FOR AUTOMOBILES Joe White, Anderson, Ind., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application April 26, 1940, Serial No. 331,821
This invention relates'to systems of electrical control for automobile use and the object of the invention is to provide a system the status of which will be dependent upon whether or not the vehicle is in motion.
In one form of the invention, the system operates to permit the sounding of the horn only when the vehicle is in motion. In another form the system operates to shift from a parking lamp circuit, used only when the vehicle is at rest, to a driving lamp circuit, used only when the vehicle is in motion.
Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing where preferred embodiments of the present invention are clearly shown,
In the drawing:
Fig. l is a wiring diagram of a horn control system for permitting the sounding of a horn only when the vehicle is in motion.
Fig. 2 is a wiring diagram of a lighting system for completing a parking lamp circuit only when the vehicle is at rest, and for completing a driving lamp circuit only when the vehicle is in motion.
Referring to Fig. l, a battery 20 will supply current to a horn 2| provided relays 22, 23 and 24 are closed concurrently. Relay 22 will be closed by the closing of the control switch or horn button 25. Relay 24 will closeprovided relays 22 and 23 are closed. The closing of relay 23 is dependent upon the vehicle being in motion. The magnet coil 23a of rela 23 is not energized following the closing of relay 22 unless relay 26 is closed. Relay 26 is normally closed but, if the vehicle is at rest it will not remain closed for a period long enough to establ sh a complete circuit from the battery 26 to the horn 2|. When the vehicle is in motion relay 26 remains closed.
In order that relay 26 may be responsive to the status of the vehicle, its magnet coil 26a is connected across a Wheatstone bridge comprising resistances R1, R2, R3 and a periodic circuit breaker 30 operated from the speedometer cable or other part which revolves only when the vehicle is in motion. The periodicity of the breaker 3D and the characteristics of the resistances R1, R2 and R3 are so related that the opening and closing of breaker 30 causes reversals of current through the magnet coil 26a. The relay 26 is built to provide a lagging action; that is, the relay 26 is so sluggish in action that it cannot respond promptly to reversals of current through the magnet coil 26a. Therefore relay 26 remains closed even tho the vehicle is moving very slowly. Therefore, so long as the vehicle is in motion, the relay 26 will remain closed; and the horn can be sounded by closing the horn switch 25.
When the vehicle is at rest, the closing of the horn switch 25 would appear to effect the closing of relay 23 as well as relay 22 since relay 26 is normally closed. But, since current will flow in one direction through winding 26a regardless of the status of the breaker 30, following the closing of relay 22 and following the closing of switch 25, relay 26 will open. It may happen that relay 23 will close ahead of the opening of rela 26, but relay 24 is provided with sufficient lag so that it does not close before relay 26 opens. Therefore, before relay 24 can close, the relay 23 will have started to open due to the opening of relay 26. In this way the completion of the circuit from the battery 2|) to the horn 2| is prevented unless the vehicle is in motion.
In Fig. 2, the Wheatstone bridge resistance members R1, R2 and R3 and the periodic circuit breaker are in the same relation to relays 22, 23 and 26 as in Fig. 1. Instead of the rela 24, there is a circuit-shifting solenoid switch 46 comprising fixed contacts 4| and 42 normally bridged by movable contact 45 and urged into this position by spring 46. Contact 45 is moved by the solenoid, when energized, to bridge contacts 43 and 44. Contact 45 is moved by armature 41 when attracted by attracting coil 49 and holding coil 48. After movement of armature 41 to position for causing contact 45 to engage contacts 43 and 44, the armature is held in this position by the energization of coil 48 alone, coil 49 having been open-circuited by engagement of a button 50, fixed to the armature, with a resillent contact 5| to cause it to separate from grounded fixed contact 52. Contact 43 is connected with head or driving lamps 53, and contact 4| with parking lamps 54. Contacts 42 and 44 are connected with a fixed contact 6| of a manually controlled lighting switch having also a fixed contact 63 connected with battery 20, and a fixed contact 64 connected with a tail lamp and the magnet coil 22a of relay 22. A movable contact 62 (having off position 62a) bridges contacts 6|, 63 and 64 in the on position.
When the vehicle is at rest and the switch 60 is closed current will flow from the battery 20 to the tail lamp 65 and to any instrument lamp which might be connected on the same circuit, also to the parking lamps 54 through switch contact ll, and also to the coil 22a of relay 22 causing relay 22 to close. Then current flows to the Wheatstone bridge and relay coil 26a is energized to cause relay 26 to open, thus preventing anything more than momentary energization of relay coil 23. Altho relay 23 might momentarily close before relay 26 opens, the solenoid 40 is too sluggish to close to shift from the parking lamp to the driving lamp circuit. Therefore, the parking lamps 54 burn while the vehicle is at rest and not the driving lamps 53.
When the vehicle moves, periodic circuit breaker 30 operates to cause alternations in direction of current fiow through relay coil 26a. Relay 26 closes because the alternations weaken the energization of its coil 26a and relay 28 remains closed. Thus the circuit between battery and magnet coil 23a of relay 23 is closed. Relay 23 closes to connect the battery 20 with solenoid windings 49 and 48. Solenoid armature 41 moves to the left to cause the parking lamp circuit to be broken and the driving lamp circuit to be completed. Therefore the mere movement of the vehicle causes the driving lamps to burn and the parking lamps to go out. Thus the driver is relieved of the duty of turning on driving lights when driving away from a parked position. All that is required is to close switch 60. He will naturally do this anyway in order to obtain instrument and ignition key-hole lighting. Conversely, the driver is relieved of the duty of turning off driving lamps and turning on parking lamps when parking at night. When the vehicle stops, the shift from driving to parking lamps takes place automatically because relay 26 opens as soon as circuit breaker 30 stops operating. Very often a driver forgets to turn oil driving lamps when parking, this resulting in needless discharge of the storage battery.
From the foregoing description of the construction and mode of operation of two forms of the present invention it is apparent that the invention contemplates the use of a Wheatstone bridge all legs of which have fixed resistance when the vehicle is at rest. and one leg of which changes in resistance periodically from zero to infinity when the vehicle is in motion. Instead of the usual voltmeter coil bridging the intermediate points, there is a magnet coil of a relay. When the resistance of one leg alternates between zero and infinity, the magnet coil is subjected to alternations in current flow. The relay being slow acting, does not operate when the vehicle is in motion but operates when the vehicle is at rest. Thus the status of the relay whose magnet coil is the bridging unit of the Wheatstone bridge is made dependent upon whether the vehicle is at rest or is in motion. Through this relay, other circuits can be established when the vehicle moves, or cannot be established when the vehicle is at rest.
While the embodiments of the present invention as herein disclosed, constitutes a preferred form. it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.
What is claimed is as follows:
1. A system of electric control for a current consuming device on an automotive vehicle comprising, a current source, a current consuming device, a means for making a connection between the source andthe device, an electro-magnet, means responsive to the energization of said electro-magnet for preventing the operation of the circuit-making means. a vehicle operated makeand-break device and means cooperating with the source and electro-magnet and the device for causing current to fiow through the electromagnet in one direction when the device is in circuit-making status and for causing current to fiow through the electro-magnet in the opposite direction when the device is in circuit breaking status, the reversal of current being so frequent when the vehicle is in motion that the electro-magnet is not effective.
2. A system of electric control for a current consuming device on an automotive vehicle comprising, a current source, a manually controlled switch, a Wheatstone bridge connected with the current source by said switch, said bridge comprising a branch having two fixed resistances in series and a branch comprising a fixed resistance and a circuit breaker operated by the vehicle, and a bridge circuit connecting the mid-points of the two branches and including a relay magnet coil, a slow-acting relay including the magnet coil of said bridge circuit and having a pair of normally closed contacts opened by the flow of current through said magnet coil, the direction of current fiow through said magnet coil depending on whether the circuit breaker contacts are opened or closed, the rapid opening and closing of the circuit breaker contacts when the vehicle is in motion causing such frequent reversals of current flow through the magnet coil that the magnet coil is insufficiently energized to separate the normally closed contacts, and means dependent upon the closing of the manually operated switch and the closed condition of the relay contacts for maintaining connection between the current source and the current consuming device so long as the manually operated switch is closed.
3. A system of electric control according to claim 1, the means which makes connection between the source and current consuming device, including a relay switch whose electromagnet is slower to become effective than the first mentioned electromagnet, whereby, when the vehicle is at rest, the first mentioned electromagnet becomes effective to prevent operation of said circuit-making means ahead of the operation of said electromagnet.
4. A system of electric control for a current consuming device for an automotive vehicle comprising, a current source, a manually closed switch, and a relay switch and a current consuming device in series with the current source, said relay switch having normally open contacts and having a magnet coil which, when engaged, effects closing of the relay switch; a Wheatstone bridge connected with the current source, said bridge comprising a branch having two fixed resistances in series and a branch comprising a fixed resistance and a circuit breaker operated by the vehicle, and a bridge circuit connecting the mid-points of the two branches and including a second relay magnet coil, a slow-acting relay including the magnet coil of the bridge circuit having less time lag than the first mentioned coil and having a pair of normally closed contacts open by the flow of current through said second magnet coil, the direction of current-flow through the second coil dependin on whether the circuit breaker contacts are open or closed, the rapid opening and closing of the circuit breaker contacts when the vehicle is in motion causing the such frequent reversals of current flow through the second coil that the said magnet coil is insufliciently energized to separate the normally closed contacts and thus permit the first mentioned magnet coil having the greater time lag to be energized to close its switch and connect the current consuming device with the source.
5. A system of electric control for a current consuming device on an automotive vehicle comprising, a current source; a current consuming device; a manually controlled switch; a vehicle operated make-and-break device; a first relay switch having normally closed contacts and having a slow acting magnet coil; means cooperating with the source and the magnet coil and the make-and-break device for causing current to flow through the said magnet coil in one direction when the make-andbreak is in circuit making status and for causing current to flow through the magnet coil in the opposite direction when the device is in circuit breaking status, the reversal of current bein: so frequent when the vehicle is in motion that the magnet coil is not effective to open the normally closed switch; a second relay switch having normally open contact connected in series with the manually operated switch and having its magnet coil connected with one of the contacts of the first mentioned relay switch and energizable only when said contacts are closed; and a third relay switch in series with the second switch for connecting the current consuming device with the source, said switch having normally open contacts and having a magnet coil which is slower acting than the first mentioned magnet coil, said coil being connected with the source upon closure of the second mentioned relay switch, whereby, when the vehicle is at rest the first mentioned magnet coil will be effective to open the contact of the normally closed relay switch upon closure of the manually operated switch before the third magnet is eifective to close its switch, the opening of the first switch causing the second mentioned magnet coil to become deenergized.