RADIO CONTROLLED SYSTEM FOR GARAGE DOOR OPENER

• US 3,716,865 A
• Filed: 06/10/1971
• Issued: 02/13/1973
• Est. Priority Date: 06/10/1971
• Status: Expired due to Term

• Current Assignee: The Chamberlain Group, Inc. (The Chamberlain Group LLC)
• Original Assignee: Colin B. Willmott
• Inventors: Willmott, Colin B.
• Primary Examiner(s): Yusko, Donald J.
• Application Number:
  US05/151,862
• Time in Patent Office: 614 Days
• Field of Search: 325/37,43,105,111,164,131 343/225 340/207
• US Class Current: 341/176
• CPC Class Codes: E05F 15/77 using wireless control
• CPC Class Codes: E05Y 2900/106 for garages
• CPC Class Codes: G08C 19/26 by varying pulse repetition frequency

Abstract

A closure operator including a simultaneously and synchronously pulsed and frequency modulated transmitter for use in conjunction with a remote receiver for controlling a closure operator and in which the range of control is substantially increased over prior art transmitters. By frequency modulating the pulse output of the transmitter, more energy will be received by the receiver without exceeding the radiation limits as established by the Federal Communications Commission thus allowing greater range. The circuit also utilizes a split stator type tuning capacitor in the transmitter which provides for a relatively constant frequency deviation component over a wide RF carrier tuning range.

Claims

1. A transmitter for remote control comprising:

a carrier frequency oscillator which includes a frequency contRolling circuit;

a tone oscillator connected to said carrier frequency oscillator to key it on and off at the tone frequency;

an FM modulator;

a voltage variable capacitor forming a part of said FM modulator and said voltage variable capacitor connected to said frequency controlling circuit of said carrier frequency oscillator; and

an integrating circuit receiving an input from said tone oscillator and supplying an output to said voltage variable capacitor.

2. A transmitter according to claim 1 wherein said integrating circuit comprises a resistor in series between said voltage variable capacitor and said tone oscillator and a capacitor connected in parallel with said tone oscillator.

3. A transmitter for remote control comprising:

a carrier frequency oscillator which includes a frequency controlling circuit;

a tone oscillator connected to said carrier frequency oscillator to key it on and off at the tone frequency;

an FM modulator;

a voltage variable capacitor forming a part of said FM modulator and connected to an output of said tone oscillator; and

said frequency controlling circuit including a split stator capacitor having two capacitor portions and said voltage variable capacitor connected between said two capacitor portions.

4. A transmitter according to claim 3 wherein said split stator variable capacitor includes means for simultaneously varying the capacitance of said two capacitor positions.