Hypodermic cannula
First Claim
1. A tissue-penetrating cannula which comprises a tube having an outer wall, and a sharp end defined by a first cut surface defining an acute angle to the longitudinal axis of said tube and forming a generally oval tube edge defining a similar acute angle to said longitudinal axis;
- a second cut surface defined along a right hand forward portion of said oval tube edge and a third cut surface defined along a left hand forward portion of said oval tube edge, said second and third cut surfaces defining between them a forward cutting surface in said tube edge; and
a fourth cut surface intersecting the second and third cut surfaces to cause said cutting surface to be spaced inwardly from said outer wall.
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Accused Products
Abstract
A tissue penetrating cannula comprises a tube having a sharp end formed by a first cut surface defining an acute angle to the longitudinal axis of the tube and forming a generally oval tube edge defining a similar acute angle to the longitudinal axis. A second cut surface is defined along a right hand forward portion of the oval tube edge, and a third cut surface is defined along a left hand forward portion of the oval tube edge. A second and third cut surfaces define between them a forward cutting surface in the tube edge. A fourth cut surface at the point intersects the second and third cut surfaces to cause the cutting surface to be spaced inwardly of the tube outer wall.
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Citations
9 Claims
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1. A tissue-penetrating cannula which comprises a tube having an outer wall, and a sharp end defined by a first cut surface defining an acute angle to the longitudinal axis of said tube and forming a generally oval tube edge defining a similar acute angle to said longitudinal axis;
- a second cut surface defined along a right hand forward portion of said oval tube edge and a third cut surface defined along a left hand forward portion of said oval tube edge, said second and third cut surfaces defining between them a forward cutting surface in said tube edge; and
a fourth cut surface intersecting the second and third cut surfaces to cause said cutting surface to be spaced inwardly from said outer wall. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- a second cut surface defined along a right hand forward portion of said oval tube edge and a third cut surface defined along a left hand forward portion of said oval tube edge, said second and third cut surfaces defining between them a forward cutting surface in said tube edge; and
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8. The method of forming a point on the end of a tissue-penetrating cannula having an outer wall, which comprises cutting a first surface adjacent an end of said cannula defining an acute angle to the longitudinal axis of said cannula to form a generally oval tube edge defining a similar acute angle to said longitudinal axis;
- cutting a second cut surface along a right hand forward portion of the oval tube edge, rotated at a clockwise angle to said first cut surface;
cutting a third cut surface along a left hand forward portion of the oval tube edge, rotated at a counterclockwise angle to said first cut surface, whereby said second and third cut surfaces define between them a forwardmost cutting surface in the tube edge; and
cutting a fourth cut surface at said forwardmost cutting surface intersecting the second and third cut surfaces, to cause said cutting surface to be spaced inwardly from said outer wall. - View Dependent Claims (9)
- cutting a second cut surface along a right hand forward portion of the oval tube edge, rotated at a clockwise angle to said first cut surface;
Specification