US2665689A - Needle assembly and method of producing said assembly - Google Patents

Description

Jan. 12, 1954 w. F. BUTLER NEEDLE ASSEMBLY AND METHOD OF PRODUCING SAID ASSEMBLY Filed "July 3, 1951 INVENTOR. ZU/LL/AM E 19072:?

HTTOP/VEXI Patented Jan. 12, 1954 NEEDLE ASSEIVIBLY AND METHOD OF PRODUCING SAID ASSEMBLY William F. Butler, Oakland, Calif., assignor to Cutter Laboratories, Berkeley, Calif., a corporation of California Application July 3, 1951, Serial No. 235,051

1 Claim. 1

This invention relates to hollow needle assemblies for use in taking blood from a donor and for establishing communication between the interior and exterior of an intravenous solution flask.

Presently, needle assemblies of this character consist of a hollow needle or cannula bonded to a metal hub to which the usual elastomer tubing is connected and which serves as a finger grip for manipulating the device. The connection between the cannula and hub must be airtight for frequently the device is used in conjunction with a partially evacuated flask. The assembly must be fairly rugged for the needle sometimes has to be forced through a substantial length of rubber stopper.

In general the object of this invention is the provision of a needle assembly fulfilling the above conditions and which also can be made at a price sufliciently low to permit of its being thrown away after its first use so as to avoid the inconvenience and cost of sterilizing it for further use and the danger of improper sterilization.

More specifically, the object of this invention is the provision of a needle assembly including a metal cannula having a roughened outer surface and a plastic hub molded thereto in airtight sealing engagement therewith.

The invention possesses other advantageous features, some of which, with the foregoing, will be set forth at length in the following description where that form of the invention which has been selected for illustration in the drawings accompanying and forming a part of the specification is outlined in full.

In said drawings, two forms of the invention are shown, but it is to be understood that it is not limited to such forms, since the invention as set forth in the claim may be embodied in other forms.

Referring to the drawings:

Fig. 1 is a plan view of a pair of needle assemblies attached to the opposite ends of a section of elastomer tubing and each embodying the objects of my invention.

Fig. 2 is an axial mid-section taken through the lower of the two needle assemblies illustrated in Fig. 1.

assemblies includes a hollow stainless steel or cannula needle I having a beveled point 2 and an extended sandblasted peripheral surface 3. Molded to the sandblasted portion of the cannula I is a plastic (polystyrene) hub 4 provided intermediate its ends with a radial flange 5 and a formed inner end with a counterbore or recess 6. As illustrated in Fig. 1 the inner recessed end of each assembly is connected to a section of elastomer tubing 1. The only difference between the two assemblies illustrated resides in the flanges 5, the flange of upper assembly being somewhat larger than the lower assembly and slightly dished.

Contrary to the expectations of those skilled in the art I have found that the surface of a stainless steel cannula can be roughed sufliciently by sandblasting or by acid etching to enable an air-tight seal to be made between the cannula and a plastic hub molded thereto and to provide a bond strength of greater than 40 pounds of axial force.

As a result of this expedient, my assignee, Cutter Laboratories, is now able to market needle assemblies having plastic hubs at a price permitting of their disposal once they have been used and therefore obviating the sterilization required of the more costly all-metal assemblies.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

A needle assembly comprising: a stainless steel cannula having a sandblasted outer surface portion; and a plastic hub molded around said cannula about said sandblasted outer surface portion, said hub being formed with a radially extending flange intermediate its ends.

WILLIAM F. BUTLER.

References Cited in the file of this patent UNITED STATES PATENTS Number

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