Abstract The output shaft of a motor is connected directly to a worm shaft which moves a traveler connected to the door. The motor includes a second centrifugal switch in the relay coil circuit whereby the motor will stop upon the door engaging stops in either direction. The worm shaft includes a length of spiral wire locked in place on thin wall tubing rectangular in cross section. The method of producing the worm shaft includes placing the length of spiral wire on a length of cylindrical tubing and then applying pressure to the tuning between adjacent coils causing corners to be formed which lockingly engage the wire coils. A predetermined axial force in either direction on the motor will cause the motor to move relative to the traveler and actuate an interrupter switch and a reversing switch thereby stopping the motor. Upon the relay coil being reactivated the motor will then move in the opposite direction to the end of the cycle where it will then shut off and be ready to repeat the cycle.
The method of forming a worm shaft comprising the steps of inserting a hollow tube into a length of spiral tube, and applying external pressure at uniformly peripherally spaced apart points to said tube between turns of said spiral wire such that said tube is deformed outwardly at corners between said points into locking engagement with said spiral wire.
Claim 2
Independent Claim
59 words
The method of forming a worm shaft comprising the steps of inserting a hollow tube into a length of spiral tube, and applying external pressure at uniformly peripherally spaced apart points to said tube between turns of said spiral wire such that said tube is deformed outwardly at corners between said points into locking engagement with said spiral wire.
Claim 3
Dependent Claim
45 words
The method of claim 1 wherein said hollow tube is circular in cross section and pressure is applied uniformly around the periphery at four positions such that the resulting tube is square in cross section and engages said spiral wire only at the four corners.
Claim 4
Dependent Claim
37 words
The method of claim 2 wherein the cross sectional sizes of said tube and length of spiral wire are such that said tube is loosely positioned in said length of spiral wire prior to pressure being applied.
Claim 5
Dependent Claim
28 words
The method of claim 1 wherein the application of pressure to said tube causes said tube to bulge outwardly at said corners between turns of said spiral wire.