Title: Door operating apparatus

Abstract: A reversible motor operates a vertically movable door through transmission means including a friction clutch. Control means receiving the output of a tachometer generator driven by the driven member of the friction clutch are arranged to switch off the motor automatically in response to a predetermined deviation downwards of the rate of rotation caused by an obstruction in the path of the door. The system may include means for automatically re-starting the motor in the opposite direction subsequent to a switching-off caused by an obstruction to the travel downwards of the door.

Do you think this is a good invention? Vote now:

Votes so far: For:(0) Against:(0)
Other info:

Inventors: Johansson, Tryggve J. (Alvangen, SE)

Application Number: 836970
Filing Date: 1977-09-27
Publication_date: 1980-03-04
Assignee:
Primary Class(es): 318/464 318/466, 318/484
Other Classes:
US Patent Ref:

2713138

Jul, 1955

Lanfers et al.

318/464.

Other Refs: Other References: Montgomery Ward Residential Automatic Garage Door Opener Owners Manuel, 9-70.