ELECTRICAL DEICER FOR AIRCRAFT PROPELLER

• US 3,657,514 A
• Filed: 06/03/1970
• Issued: 04/18/1972
• Est. Priority Date: 06/03/1970
• Status: Expired due to Term

• Current Assignee: Lowell J. Adams
• Original Assignee: Lowell J. Adams
• Inventors: Adams, Lowell J.
• Primary Examiner(s): Truhe, J. V.
• Assistant Examiner(s): Peterson, Gale R.
• Application Number:
  US05/042,945
• Time in Patent Office: 685 Days
• Field of Search: 219/201,202 244/134D,134R
• US Class Current: 219/201
• CPC Class Codes: B64D 15/12 by electric heating electric heating elements in general H05B
• CPC Class Codes: B64D 15/14 controlled cyclically along length of surface

Abstract

Multiple heater deicer boots for propeller blades having a power source on the aircraft and an electrical connection through brushes and slip rings. Rectifiers are incorporated in the heater circuits and switches are provided for changing the polarity of voltage applied to the two wires connected to the heater circuits so that two brushes and two slip rings provide the electrical connection between the aircraft and rotating propeller for cycling power separately to each heater in the deicer boots.

Claims

1. An aircraft propeller electric deicer assembly in which a boot containing two resistance-type electric heaters is mounted on a propeller blade and power to operate said heaters is supplied from a DC power source on the airplane through two brushes engaging respective slip rings mounted on the propeller wherein the improvement comprises a heater circuit having a pair of lead wires, each of which is connected to a separate slip ring and carrying power to said heaters, a pair of diode rectifiers located in said circuit so that when current flows in one direction through said circuit current will be unidirectionally conducted through one of said diode rectifiers to one of said heaters and when current flows in the opposite direction through said circuit, current will be unidirectionally conducted through the other of said heaters and voltage reversing switch means in connection between said brushes and said DC power source for reversing the polarity of connection of said DC power source to said brushes, thereby to reverse the current flow in said circuit to direct power individually and selectively to said heaters through said diode rectifiers.

2. An aircraft propeller electric deicer assembly according to claim 1 wherein the propeller has more than one blade and two said slip rings, each said blade has a boot with a heater circuit having a pair of lead wires, and each lead wire of said pair being connected to a separate slip ring.

3. An aircraft propeller electric deicer assembly according to claim 1 wherein said voltage means comprises a timer for cyclically changing the direction of current flow in said circuit after a period of time.

4. An aircraft propeller electric deicer assembly according to claim 1 wherein said diode rectifiers are semi-conductor diodes characterized by relatively large current flow in one direction and very small current flow in the reverse direction.

5. An aircraft propeller electric deicer assembly according to claim 10 wherein each of said diode rectifiers is a silicon diode.

6. An aircraft propeller electric deicer assembly for a propeller having two blades, a first deicer boot mounted on one of said blades and a second deicer boot mounted on the other of said blades, an electrical circuit including a first pair of heaters with one heater mounted in said first boot and one heater mounted in said second boot, a second pair of heaters with one heater mounted in said first boot and one heater mounted in said second boot, said first pair of heaters being connected in parallel in a first line, said second pair of heaters being connected in parallel in a second line, a first diode rectifier connected in series in said first line, a second diode rectifier connected in series in said second line, a pair of slip rings on the propeller, each end of said first line being connected to a separate one of said slip rings, each end of said second line being connected to a separate one of said slip rings, DC power means mounted on the aircraft connected to said separate slip rings by brushes and voltage reversing switch means between said power means and said brushes, said switch means being operative to reverse the connection of said power means to said brushes thereby to reverse current flow in said circuit to cyclically conduct power to said first pair of heaters through said first diode rectifier and then through said second pair of heaters through said second diode rectifier.

7. An aircraft propeller deicer assembly according to claim 6 wherein said first diode rectifier is connected in parallel with said second pair of heaters and said second diode rectifier is connected in parallel with said first pair of heaters.