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Slack-Free Knob for Flatted Shaft

IP.com Disclosure Number: IPCOM000046267D
Original Publication Date: 1983-Jun-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Welder, JW: AUTHOR

Abstract

Knob 10 has a control hole 11 for receiving a conventional control shaft 20 having a flat 21. Tolerances in hole 11 and shaft 20 conspire to create slackness or play when knob 10 is rotated. Present methods of tightening such a knob involve added expense, tools or assembly operations, and many will fail after repeated disassembly and reassembly for servicing.

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Slack-Free Knob for Flatted Shaft

Knob 10 has a control hole 11 for receiving a conventional control shaft 20 having a flat 21. Tolerances in hole 11 and shaft 20 conspire to create slackness or play when knob 10 is rotated. Present methods of tightening such a knob involve added expense, tools or assembly operations, and many will fail after repeated disassembly and reassembly for servicing.

Knob 10 is simple, reliable, secure, and inexpensive. Knob body 12 holds the ends of a B-shaped spring wire 13 in longitudinal grooves 14. The straight back of spring 13 rests in transverse groove 15. As seen most clearly in the enlarged cross section of Fig. 3, groove 15 has a bottom area 16, in which wire 13 normally rests, and at least one inclined wall 17 extended part or all the way up one side of the groove.

When shaft 20 is inserted into hole 11 from right to left, its blunt end pushes spring 13 up and to the left along inclined wall 17, then rides along the top of flat 21 until the shaft stops. Flexure of the bows of spring 13 holds it firmly and reliably against flat 21 to prevent rotational slack, yet allow knob 10 to be assembled and disassembled any number of times without degradation.

Wall 17' is also inclined, so that shaft 20 can be inserted from either end of hole 11; if this is not required, a vertical wall 17' would allow the length of body 12 to be reduced somewhat.

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