Knob locking and drag device

• US 4,154,125 A
• Filed: 07/05/1977
• Issued: 05/15/1979
• Est. Priority Date: 07/05/1977
• Status: Expired due to Term

• Current Assignee: Beckman Industrial Corporation
• Original Assignee: Beckman Instruments, Inc. (Danaher Corporation)
• Inventors: Frank, Edgar H.
• Primary Examiner(s): Braun, Leslie
• Application Number:
  US05/813,194
• Time in Patent Office: 679 Days
• Field of Search: 74/553, 74/483 PB, 74/511 R, 74/504, 74/511 A, 248/27.1, 248/27.3, 16/121, 200/61.54, 200/321, 200/325, 200/336, 200/296
• 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: G05G 5/12 for holding members in an indefinite number of positions, e.g. by a toothed quadrant G05G5/28 takes precedence
• CPC Class Codes: H01C 10/14 adjustable by auxiliary driving means
• CPC Class Codes: Y10T 74/2084 Knob or dial

Abstract

A device for use with variable electrical components such as potentiometers to provide not only an independent means adjacent the control knob to lock the knob in a fixed position, but also to provide variable amounts of drag on the knob to enhance more precise and accurate control of the knob. The locking device is positioned between the controlled component and the control knob. The locking device can be moved to a plurality of positions adjacent the control knob to vary the amount of drag on the control knob.

Claims

1. A locking device assembly on a control shaft for an adjustable component, said device comprising:

a control shaft for said component;

a control knob on said shaft, rotational movement of said knob rotating said shaft to move said component, said shaft being rotatable more than 360 degrees;

a bushing mounted on said shaft between said knob and said component, said bushing being stationary with respect to rotative movement of said control shaft;

a holding member threadably engaged on said bushing, said holding member movable in a longitudinal direction with respect to said shaft toward and away from said knob; and

a locking washer on said shaft between said holding member and said knob, said washer movable in said longitudinal direction along said shaft and being nonrotatable with said rotatable holding member, said holding member movable in said longitudinal direction between a first position and a second position and a plurality of positions between said first and second positions, said holding member in said first position placing said locking washer in tight contact with said knob to lock said knob, said holding member in said second position placing said locking washer out of contact with said knob to allow free movement of said knob, said holding member in each of said plurality of positions between said first and second positions providing a different amount of tightness of contact of said locking washer against said knob than in any of the other of said plurality of positions to vary the amount of drag desired on the knob to enhance fine tuning adjustment of said component.

2. A locking device as defined in claim 1, wherein said bushing has at least one slot.

3. A locking device as defined in claim 2, wherein said locking washer has an inward projection for receipt in said slot to prevent rotation of said locking washer relative to said bushing.

4. A locking device as defined in claim 1, wherein said holding member has a central recessed portion for receipt of said control knob.

5. A locking device assembly on a control shaft for an adjustable component, said device comprising:

a control shaft for said component;

a control knob on said shaft, rotational movement of said knob rotating said shaft to move said component;

a bushing mounted on said shaft between said knob and said component;

a holding member threadably engaged on said bushing, said holding member movable in a longitudinal direction with respect to said shaft toward and away from said knob;

a locking washer on said shaft between said holding member and said knob, said washer movable in said longitudinal direction along said shaft and being nonrotatable with said rotatable holding member, said holding member movable in said longitudinal direction between a first position and a second position and a plurality of positions between said first and second positions, said holding member in said first position placing said locking washer in tight contact with said knob to lock said knob, said holding member in said second position placing said locking washer out of contact with said knob to allow free movement of said knob, said holding member in each of said plurality of positions between said first and second positions providing a different amount of tightness of contact of said locking washer against said knob than in any of the other of said plurality of positions to vary the amount of drag desired on the knob to enhance fine tuning adjustment of said component; and

a support ring in said holding member for receipt of said locking washer, said ring having a width smaller than the width of said washer to provide a more concentrated pressure of said washer on said control knob when said washer is in said first position.

6. A locking device assembly on a control shaft for an adjustable component, said device comprising:

a control shaft for said component;

a control knob on said shaft, rotational movement of said knob rotating said shaft to move said component;

a bushing mounted on said shaft between said knob and said component;

a holding member rotatably engaged on said bushing for movement toward and away from said knob;

a locking washer located on said bushing between said holding member and said knob, said locking washer movable by said holding member toward said knob to a completely locked position and away from said knob to a completely unlocked position, said locking washer movable to a plurality of positions between said locked and unlocked positions to set a variable amount of desired drag on said knob to enhance fine tuning adjustment of said component; and

means on said locking washer and said bushing for preventing rotational movement of said locking washer as said holding member rotates to move toward and away from said knob, said rotational movement of said knob in either direction not affecting the setting of said drag on said knob.