Twin sprocket garage door opener

• US 4,794,731 A
• Filed: 06/15/1987
• Issued: 01/03/1989
• Est. Priority Date: 06/15/1987
• Status: Expired due to Term

• Current Assignee: The Chamberlain Group, Inc. (The Chamberlain Group LLC)
• Original Assignee: The Chamberlain Group, Inc. (The Chamberlain Group LLC)
• Inventors: Willmott, Colin B., Chang, James S.
• Primary Examiner(s): Dorner, Kenneth J.
• Assistant Examiner(s): Anderson, Gerald A.
• Application Number:
  US07/061,975
• Time in Patent Office: 568 Days
• Field of Search: 49/197, 49/199, 49/324, 49/360, 474/158, 474/159, 474/160, 474/140, 474/151, 474/78
• US Class Current: 49/199
• CPC Class Codes: E05F 15/684 by chains
• CPC Class Codes: E05Y 2201/646 continuous, e.g. closed loops
• CPC Class Codes: E05Y 2800/00 Details, accessories and auxiliary operations not otherwise provided for
• CPC Class Codes: E05Y 2900/106 for garages

Abstract

An adjustable speed garage door operator which has a longitudinal rail with a trolley mounted on the rail and connected to a door to open and close it. A chain is connected to the trolley and is mounted on a front idler sprocket and can be selectively mounted on different drive sprockets which have different numbers of teeth so as to vary the speed of the door.

Claims

1. An adjustable speed garage door operator for a garage door comprising, a frame member, a motor mounted on said frame member, an output shaft coupled to said motor and rotatably mounted on said frame member, a plurality of sprockets with different number of teeth mounted on said output shaft, a longitudinal rail member with one end attached to said frame member, a trolley movably mounted on said rail and connected to said garage door, an endless chain, a front sprocket rotatably mounted to said rail and said chain mounted thereon, and said chain selectively mountable on one of said plurality of sprockets so as to select a particular operating speed for said garage door operator, including an idler pulley rotatably and adjustably mounted to said frame member adjacent to said plurality of sprockets and said chain engageable with said idler pulley so as to guide said chain over a selected one of said plurality of sprockets, and wherein said idler pulley is mounted on a vertical pulley shaft which is connected to said frame member and said idler pulley is formed with a collar on one side such that by inverting it on said pulley shaft the height of said idler pulley can be adjusted so as to align it with different ones of said plurality of sprockets.

2. An adjustable speed garage door operator according to claim 1, wherein said idler pulley is formed with an annular guide extension which engages said chain to hold it on said idler pulley.