Screw thread cutting member
OwnerTimothy J. R. Barnsdaleinventor
Life of this patent
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Abstract
A male screw thread-formed member such as an insert having a thread cutting action has an exterior peripheral portion of substantially full V-thread form along which two or more angularly spaced apart flutes extend from one or both ends of the member, the member being provided with at least one non-helical rib initially of generally annular peripheral V-form at one or both ends thereof and on which is formed a varying reduced V-thread form which follows a helix corresponding to that of the full thread form whereby pointed cutting formations providing peaks of different radial heights and with some of them of offset disposition relative to the helix are formed on the or each rib at the flutes for effecting a distributed thread cutting action thereat, e.g., for use in thermo-setting plastic material.
Claims6
A male screw thread-formed member having a thread cutting action, comprising a generally cylindrical body having at least two angularly spaced apart longitudinal flutes each defined by a groove in the outer periphery of said body and extending along the body from at least one end thereof, said body also having a helically threaded portion of substantially full V-thread form about said outer periphery with said flutes extending into said thread form, said body further having at at least said one end thereof at least one rib of substantially helical form of generally peripheral V-form in cross section adjacent said threaded portion and of reduced diameter relative thereto and co-axial therewith, said rib having said flutes passing through the periphery thereof to thereby form between said flutes a plurality of reduced V-thread formations of varying cross section and relative radial heights;
- which follow a helix corresponding to that of the substantially full V-thread form whereby resulting pointed cutting formations provide peaks of different radial heights, and at least some of said rib formations are positioned, at the intersection of said formations and said flutes, in offset disposition relative to said helix of said threaded portion for effecting a distributed thread cutting action thereat.
Dependencies are inferred from the claim text.