Lockable rotatable knob

• US 3,916,721 A
• Filed: 07/03/1974
• Issued: 11/04/1975
• Est. Priority Date: 09/05/1973
• Status: Expired due to Term

• Current Assignee: Erwin Egger
• Original Assignee: Erwin Egger
• Inventors: Egger, Erwin
• Primary Examiner(s): Wyche, Benjamin W.
• Assistant Examiner(s): Shoemaker, F. D.
• Application Number:
  US05/485,622
• Time in Patent Office: 489 Days
• Field of Search: 74/553,554 403/350,373,374,DIG.8 116/115 188/74,75
• US Class Current: 74/553
• CPC Class Codes: G05G 1/10 Details, e.g. of discs, knobs, wheels or handles G05G1/085 takes precedence
• CPC Class Codes: Y10S 403/08 Radially acting cam or eccentric
• CPC Class Codes: Y10T 403/7009 Rotary binding cam or wedge
• CPC Class Codes: Y10T 403/7062 Clamped members
• CPC Class Codes: Y10T 403/7069 Axially oriented
• CPC Class Codes: Y10T 74/2084 Knob or dial

Abstract

Control knob apparatus for mounting on a control shaft of an instrument such as a potentiometer. A control knob is rotatably mounted in a housing and has an outer cylindrical brake surface in the housing. A first ring is provided in the housing and has resilient brake fingers thereon, disposed outside of and adjacent to the brake surface. A second ring surrounds the brake fingers and has cam surfaces thereon, which resiliently urge the brake fingers into braking contact with the cylindrical surface, on arcuate displacement of the second ring in one rotary direction.

Claims

1. Control knob apparatus comprising;

a housing having a generally cylindrical outside surface;

a control knob coaxial with said housing, an end of said knob being mounted in said housing and having an outer cylindrical brake surface;

a stationary brake ring, coaxially secured to said housing and having a plurality of resilient brake fingers thereon, disposed outside of and adjacent to said outer cylindrical brake surface, each finger extending over an arcuate portion of said surface;

a shiftable brake actuator ring coaxially surrounding said resilient brake fingers;

mutually coacting cam means on said shiftable ring and on said resilient brake fingers for resiliently radially urging said resilient brake fingers into braking contact with said cylindrical brake surface, on displacement of said brake actuator ring in one direction over a limited distance which is minor compared with the circumference of said cylindrical brake surface, to lock the knob, and for resiliently releasing said brake means on displacement of said shiftable brake actuator ring in an opposite direction over said limited distance; and

means coaxial with and adjacent to the outside surface of the housing and manually engageable for displacing said shiftable brake actuator ring in either direction over said limited distance.

2. Control knob apparatus according to claim 1, wherein said shiftable ring is shiftable circumferentially about the axis of said knob over said limited distance.

3. ControL knob apparatus according to claim 1, wherein said shiftable ring is shiftable longitudinally along the axis of said knob over said limited distance.

4. Control knob apparatus according to claim 1, in which said shiftable ring has externally knurled portions thereon.

5. Control knob apparatus according to claim 4, in which said externally knurled portions constitute a pair of portions disposed on diametrically opposite portions of said shiftable ring.

6. Control knob apparatus according to claim 1, in which said shiftable ring consists of synthetic plastic material.

7. Control knob apparatus according to claim 1, additionally including means controlled by said control knob for indicating the operations of said control knob.