US3427680A - Knob locking device - Google Patents

Description

Feb. 18, 1969 F. P. GILBERT KNOB LOCKING DEVICE Filed April 21, 1967 United States Patent land Filed Apr. 21, 1967, Ser. No. 632,725 Claims priority, application Great Britain, May 6, 1966,

20,191/ 66 US. Cl. 16-121 6 Claims Int. Cl. H01e /02; A47b 95/02; B65d 25/28 ABSTRACT OF THE DISCLOSURE A knob in which rotation of a locking member expands a ring to lock the knob in any position.

The invention relates to a self-locking knob.

According to the present invention there is provided a self-locking knob including a fixed resilient ring member disposed about the spindle of the knob and so as to fit within a recess of the knob and an independently rotatable locking member having a plurality of symmetrically-arranged radial extensions which, on rotation of the locking member from a free to a locking position press the ring member into engagement with the wall of the recess thereby locking the knob in any desired angular position.

The ring member may be a split annular ring and the said extensions of the locking member may extend within the gaps between the sections of the ring when the locking member is in its free position.

The split ring may project from a disc, in which case it may be made resilient by the inclusion of slits between the ring and the disc at the end of each section of the ring.

An embodiment of the invention will be described with reference to the accompanying drawings:

FIG. 1 is an exploded perspective view of a potentiometer knob,

FIG. 2 is a horizontal section of the knob shown in FIG. 1.

In FIG. 1 there is illustrated a knob head for a potentiometer 1 which is attached to a frame 2. The knob head 3 is mounted on one end of a spindle 4 protruding from a threaded bush 5 which forms part of the potentiometer and which enables the potentiometer to be secured to the frame by means of a thin hexagonal nut 6. The end of the knob head has a cylindrical recess (not shown) which houses a brass ring 7. The knob head may be moulded with the ring 7 as an insert or the ring may have an inwardly-directed flange on its upper edge adapted to engage a structure designed to be secured to the spindle and over which the knob head is then fitted. The ring is designed so as to fit loosely round two ring-sections 8 which are fixed to the frame 2. The sections have slits 9 which provide resilient tongues 10.

The locking member 11 is rotatable about the knob spindle and has a handle 12 and two opposing extensions 3,427,680 Patented Feb. 18, 1969 13 having curved edges 14. These extensions have a radius which is between that of the inner and outer radii of the sections, so that when these pieces are in the gap between the sections the knob is free to rotate. However, rotation of the member, in a clockwise manner, will allow the extensions to slide in front of the tongues 10, forcing the tongues .10 outwards so that they press firmly against the surrounding ring and lock the knob.

I claim:

'1. A self-locking knob comprising,

a spindle,

a knob-head mounted on one end of said spindle and having a recess of circular cross-section surrounding said spindle,

means for rotatably mounting said spindle on a frame,

a resilient ring member fitting within said recess of said knob head and arranged to be fixed to said frame,

a locking member rotatably mounted on said spindle,

means for rotating said locking member with respect to said spindle and said frame, and

a plurality of symmetrically-disposed extensions on said locking member arranged to engage said ring member on rotation of said locking member from a free to a locking position and to urge said ring member into locking engagement with said knob-head.

2. A knob according to claim 1 in which said ring member comprises a split annular ring having symmetrically-disposed sections and in which said extensions extend 'within the gaps between said sections when said locking member is in said free position.

3. A knob according to claim 2 further comprising a cup-shaped member having a base adapted to be fixed to said frame and having split walls forming said split ring.

4. A knob according to claim 3, wherein said cupshaped member includes slits between said base and said walls and extending from the gaps between said sections.

5. A knob according to claim 4 further comprising a further ring fixed within said recess so as to form an internal wall of said recess against which said ring member is urged when in locking engagement.

6. A knob according to claim 1 further comprising a further ring fixed within said recess so as to form an internal wall of said recess against which said ring member is urged when in locking engagement.

References Cited UNITED STATES PATENTS 2,433,794 12/1947 Springman 188--7 3 3,227,985 1/1966 Hardison et al. 338162 3,366,911 1/1968 Wilson et al. 338-197 3,384,727 5/1968 Zavertnik et al. 200-169 XR DONALD A. GRIFFIN, Primary Examiner.

US. Cl. X.R.

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