Method for manufacturing a cannula assembly
AssigneeBaxter International Inc.
InventorWilliam E. Sagstetter
Life of this patent
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Abstract
The present invention is directed to a novel process for inserting a cannula, such as a hypodermic needle, into a hub member by roughening a first portion of the cannula while leaving a second portion substantially smooth such that the first portion forms an interference fit and the second portion a line-to-line fit with the hub bore. In the absence of an adhesive, the second portion is passed through the hub bore followed by the first portion. The first portion is forced into the hub bore to provide an adhesive-free interference fit that is capable of resisting puncturing forces during normal use.
Claims34
A method for manufacturing a cannula assembly including a hub member and a cannula, comprising the steps of:
- forming a roughened exterior surface on a first portion of a cannula such that the first portion of the cannula is roughened and a second portion of the exterior surface of the cannula is substantially smooth;
- and
- inserting the roughened first portion of the cannula into a central bore of a hub, wherein a first radius of the roughened first portion is larger than a radius of the hub bore to form an interference fit therebetween and a second radius of the substantially smooth second portion is the same as or slightly less than the radius of the hub bore to form a line-to-line fit therebetween, and wherein, in the inserting step, the interface between the hub bore and the cannula is free of an adhesive.
A method for manufacturing a cannula assembly including a hub member and a cannula, comprising the steps of:
- (a) grit blasting a first portion of a cannula such that the grit blasted first portion of the cannula's exterior surface is roughened relative to a second portion of the exterior surface that is substantially smooth;
- (b) inserting the substantially smooth second portion of the cannula into a bore of a hub member;
- (c) after, the inserting step (b), forcing the substantially smooth second portion to pass through the bore;
- (d) inserting the grit blasted first portion of the cannula into the bore;
- and
- (e) forcing at least most of the grit blasted first portion of the cannula into a frictional fit with the hub bore, wherein a first radius of the roughened first portion is larger than a radius of the bore to form an interference fit therebetween and a second radius of the substantially smooth second portion is the same as or slightly less than the radius of the bore to form a line-to-line fit therebetween, and wherein, in the inserting step, the interface between the bore and the cannula is free of an adhesive.
Dependencies are inferred from the claim text.