Syringe having a flexible piston rod
First Claim
1. A syringe for receiving an ampoule having a cylindrical interior of a specified first diameter, said syringe comprising:
- a flexible piston rod having a tape-shaped body, said body including opposed top and bottom surfaces and opposed sides, wherein said piston rod further includes a plurality of support members spaced axially along said body and projecting from said top surface, wherein said support members have distal ends spaced away from said body, and wherein said sides and said distal ends, when said piston rod is viewed in cross-section, lie at least generally along a circle having a diameter which is approximately the same as said first diameter so that, when said piston rod extends into the cylindrical interior of an ampoule, the sides and distal ends will abut the ampoule interior at least at three contact positions, and wherein one of said contact positions is located on a half of said circle opposite to the other two contact positions; and
a piston rod guide member for guiding a portion of said piston rod, which is located outside of an ampoule interior, along a curved guide surface.
1 Assignment
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Accused Products
Abstract
A flexible piston rod for use in cylinder ampoules comprises a tape shaped body (1) which is along its length provided with supporters (2; 6; 16) projecting from at least one side of the tape. The tape (1) has a width and the supporters a length so that sides of the tape and the free ends of the supporters abuts the inner wall of the ampoule (3) in at least three positions along the inner perimeter of the ampoule (3) and not all the abutment points lies on the same half of the circular cross section but are typically displaced about 120° from each other. The piston rod is moved by a gear engaging a rack (12) on the tape either on the side not carrying supporters or at the edge of the tape on the side carrying supporters.
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Citations
12 Claims
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1. A syringe for receiving an ampoule having a cylindrical interior of a specified first diameter, said syringe comprising:
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a flexible piston rod having a tape-shaped body, said body including opposed top and bottom surfaces and opposed sides, wherein said piston rod further includes a plurality of support members spaced axially along said body and projecting from said top surface, wherein said support members have distal ends spaced away from said body, and wherein said sides and said distal ends, when said piston rod is viewed in cross-section, lie at least generally along a circle having a diameter which is approximately the same as said first diameter so that, when said piston rod extends into the cylindrical interior of an ampoule, the sides and distal ends will abut the ampoule interior at least at three contact positions, and wherein one of said contact positions is located on a half of said circle opposite to the other two contact positions; and
a piston rod guide member for guiding a portion of said piston rod, which is located outside of an ampoule interior, along a curved guide surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification