WINDSHIELD WIPER CONTROL MEANS

• US 3,794,847 A
• Filed: 06/02/1972
• Issued: 02/26/1974
• Est. Priority Date: 06/11/1971
• Status: Expired due to Term

• Current Assignee: Jean Georges Cadiou
• Original Assignee: Jean Georges Cadiou
• Inventors: Cadiou, Jean Georges
• Primary Examiner(s): Schaefer, Robert K.
• Assistant Examiner(s): Smith, William J.
• Application Number:
  US05/259,198
• Time in Patent Office: 634 Days
• Field of Search: 200/61.05,DIG.14,DIG.40 307/117 340/52,59,235 317/DIG.3 328/4
• US Class Current: 307/117
• CPC Class Codes: B60S 1/485 including control systems responsive to external conditions, e.g. by detection of moisture, dirt or the like
• CPC Class Codes: Y10S 15/15 Moisture responsive
• CPC Class Codes: Y10S 200/14 Rail or leak indicator

Abstract

Windshield wiper control comprises a moisture detector in the form of two electrodes separated by a labyrinthine gap and positioned to be wiped by a windshield wiper blade. The motor controlling the wiper is started and stopped by a relay actuated by a control circuit containing the gap between the electrodes so as to start the wiper when the gap is bridged by moisture and stop it when the moisture evaporates. Means are provided for changing the threshold of response after the wiper has been started so that the wiper will stop when there is more moisture on the detector than is required to start it.

Claims

1. In automatic means for controlling the operation of a windshield wiper for an automotive vehicle, which means comprises a moisture detector the resistance of which is dependent on the amount of moisture to which it is subjected, said detector being inserted in the electrical control circuit of a relay for starting and stopping the wiper, and being so located that the moistness of said detector is representative of the moistness of the windshield to be wiped, the improvement according to which said detector comprises two thin narrow electrodEs spaced apart on the surface of an insulating member, said electrodes being of substantially equal length, which length is greater than the average distance by which they are separated, and the surface of said insulating member is exposed to atmospheric conditions and wiped by auxiliary wiping means coupled to the windshield wiper to be controlled.

2. Automatic control means as claimed in claim 1 in which each electrode comprises a plurality of elongated components in the form of combs having interfitting teeth.

3. Automatic control means as claimed in claim 1 in which the detector is inserted in a voltage divider which biasses the base of a transistor controlling the supply circuit of a relay which controls a motor driving said windshield wiper and is connected to open said supply circuit to prevent operation of said wiper, when the resistance of said detector is greater than a first given threshold value.

4. Automatic control means as claimed in claim 2 in which said auxiliary wiping means consists of at least one windshield wiper blade and wipes part of said windshield.

5. Automatic control means as claimed in claim 3 in which an auxiliary circuit coupled to the control means for a windshield washer is connected between the coil of said relay and said transistor.

6. Automatic control means as claimed in claim 3 in which threshold changing means controlled by the relay are connected to vary, in dependence on the position of said relay, the resistance in at least one section of the voltage divider in a manner such that, when the windshield wiper has been started, the transistor prevents closing of the relay at a value of the resistance of the detector which is lower than said first value, but returns the resistance of the voltage divider to its initial value when the windshield wiper is stopped.

7. Automatic control means as claimed in claim 3 comprising a switch inserted between the coil of the relay and said transistor, which switch is subjected to the action of the current drawn by the motor and adapted to operate in response to a certain value thereof.

8. Automatic control means as claimed in claim 3 in which the motor driving the windshield wiper is of the two-speed ferrite type, connected to operate at normal speed upon actuation of a first relay controlled by the automatic device, and connected to operate at a more rapid speed upon actuation of a second manually operated relay, the supply circuit for normal speed operation being connected to be completed only if the second relay has opened the supply circuit for rapid speed operation.

9. In an automatic device for controlling the operation of windshield wiping means for an automotive vehicle, which device comprises a moisture detector including two spaced electrodes separated by an electric gap and positioned on a surface of the windshield subjected to the action of a windshield wiper blade, which detector has a variable electrical resistance dependent upon the moistness of the surface of the windshield to be wiped and is inserted in the control circuit of an electrical relay connected to make and break the supply circuit to a motor for driving said windshield wiping means, said relay being connected to be closed and to thereby complete said supply circuit, whenever the resistance of said variable electric resistance falls below an original threshold value, the improvement according to which the two electrodes of the detector are thin and narrow and spaced from each other by a labyrinthine insulating gap, and said device comprises control means actuated upon closing of said relay to temporarily increase said threshold value and upon subsequent opening of said relay to return said threshold value to its original value.

10. A device as claimed in claim 9 in which said windshield wiping means comprises a main wiper blade and an auxiliary wiper blade, and said moisture detector is subjected only to the action of said auxiliary wiper blade.

11. A device as claimed in claim 9 in which the control mEans actuated by said relay comprises time delay means for delaying the return of said threshold value to its original value for a predetermined interval after said relay opens.