Syringe lock

• US 4,386,606 A
• Filed: 11/28/1980
• Issued: 06/07/1983
• Est. Priority Date: 12/26/1979
• Status: Expired due to Term

• Current Assignee: Boston Scientific Corporation
• Original Assignee: Waters Instruments, Inc. (Woodstream Corporation)
• Inventors: Burton, Thomas A., Tretinyak, Carl W.
• Primary Examiner(s): YASKO JR, JOHN D
• Application Number:
  US06/210,290
• Time in Patent Office: 921 Days
• Field of Search: 128/218 R, 128/218 PA, 128/218 C, 128/213, 128/215, 128/216, 128/234, 222/326, 222/386
• US Class Current: 604/220
• CPC Class Codes: A61B 5/15003 for venous or arterial blood
• CPC Class Codes: A61B 5/150236 Pistons, i.e. cylindrical bodies that sit inside the syringe barrel, typically with an air tight seal, and slide in the barrel to create a vacuum or to expel blood
• CPC Class Codes: A61B 5/150244 Rods for actuating or driving the piston, i.e. the cylindrical body that sits inside the syringe barrel, typically with an air tight seal, and slides in the barrel to create a vacuum or to expel blood
• CPC Class Codes: A61B 5/150259 Improved gripping, e.g. with high friction pattern or projections on the housing surface or an ergonometric shape
• CPC Class Codes: A61B 5/150389 Hollow piercing elements, e.g. canulas, needles, for piercing the skin
• CPC Class Codes: A61B 5/150503 Single-ended needles hollow piercing element tip design A61B5/150396, needle sets for catheters A61M25/06, needles for bringing media into the body A61M5/32
• CPC Class Codes: A61B 5/153 Devices specially adapted for taking samples of venous or arterial blood, e.g. with syringes
• CPC Class Codes: A61M 5/31501 Means for blocking or restricting the movement of the rod or piston A61M5/5013 takes precedence
• CPC Class Codes: A61M 5/31505 Integral with the syringe barrel, i.e. connected to the barrel so as to make up a single complete piece or unit

Abstract

A syringe having a barrel and a plunger moveable axially in the barrel is provided with locking means for locking the plunger to the barrel. The locking means includes cam means carried between the barrel and the plunger, and means for moving the cam into a position forcing the plunger into binding contact with the barrel.

Claims

1. In a syringe having a barrel and a plunger having radially and axially extending webs and moveable axially in the barrel:

locking means for locking the plunger to the barrel and including cam means carried by and within the barrel between the barrel and plunger, and means for moving the cam means to force the plunger into binding contact with the barrel.

2. The device of claim 1 including restraining means for restraining the cam means from axial movement with respect to the barrel.

3. The device of claim 1 wherein said means for moving the cam means comprises handle means rigidly attached to the cam and including means extending outwardly of the barrel for manual operation.

4. The device of claim 1 in which the syringe plunger includes webs extending axially along its length and radially from its axis, and in which the barrel includes a smooth, internal cylindrical wall, said wall and webs defining between them open cylindrical segments, said cam means being retained in one of said segments adjacent an open end of the barrel and having an exterior camming surface contactable with the interior surface of the barrel and with adjacent walls of the plunger webs, the cam means being rotatable between a first, unlocked position in which the plunger may readily be moved coaxially within the barrel, and a second, locked position in which the axis of the plunger is displaced in a direction normal to the axis of the barrel to bind the plunger between the barrel and cam means.

5. The device of claim 1 wherein the intersection of the cam with a plane normal to the direction of travel of the plunger defines a closed curve having a segment that is generally circular and has a substantially constant radius, and another segment that extends outwardly substantially beyond the locus of points generated by such radius.

6. The device of claim 5 in which the length of the maximum length chord across said closed curve is at least about 1.2 times the length of the longest chord across the closed curve taken perpendicular to said chord of maximum length.

7. In a syringe having a barrel with an open proximal end defined by an internally extending annular lip, and a smooth, cylindrical interior surface, and a plunger moveable axially in the barrel and having a shank comprising radially and axially extending webs spaced angularly from one another;

locking means for locking the plunger to the barrel and including cam means carried between adjacent webs of the plunger and the interior surface of the barrel and within the barrel, the cam means having a camming surface and being rotatable from a first position in which said surface contacts walls of adjacent webs but does not substantially interfere with movement of the plunger axially within the barrel, and a second, locked position in which said camming surface contacts the interior wall of the barrel and said walls of adjacent webs, urging others of said webs into binding contact with the annular lip of the barrel.

8. The device of claim 7 including retaining means retaining the cam means in a fixed, axial relationship with respect to the barrel.

9. The device of claim 7 wherein said cam means includes a grooved, peripheral surface into which is received the annular lip of the barrel to retain the cam means in a substantially fixed, axial position with respect to the barrel.

10. The device of claim 9 wherein said cam means include manually operable handle means extending outwardly of the open end of the barrel for manual movement of the cam between its locked and unlocked positions.

11. The device of claim 7 in which the intersection of the camming surface of the cam means with a plane normal to the direction of travel of the plunger defines a closed curve having a segment that is generally circular and has a substantially constant radius, and having another segment that extends outwardly substantially beyond the locus of points generated by said radius.

12. The device of claim 7 in which the camming surface is generally rectangular in cross-section.

13. The device of claim 7 in which the camming surface is generally eliptical in cross-section.

14. In a syringe having an open proximal end, a smooth, cylindrical interior surface and an annular lip extending inwardly at its proximal end, and a plunger axially moveable within the barrel, the plunger having an elongated shank portion comprising four elongated, radially and axially extending webs, each web being oriented at right angles to adjacent webs and providing, with the interior surface of the barrel, four open, longitudinal cylindrical segments, the shank extending loosely through the open end of the barrel defined by the annular lip of the barrel;

locking means for locking the plunger axially with respect to the barrel, the locking means including a cam carried in one of said cylindrical segments, a handle extending inwardly of the open proximal end of the barrel and having an arm moveable in a plane generally normal to the axis of the barrel, and connector means rigidly joining the arm at its inner end to the cam, the locking means having a peripheral groove into which the annular lip of the barrel is received, the lip coacting with the groove to prevent axial movement of the cam with respect to the barrel, the cam having a camming surface of predetermined dimensions so that the cam, when oriented in one position with respect to the barrel, permits the plunger shank to move coaxially substantially freely within the barrel, and when oriented in a second position by rotation of the handle through an arc of approximately 90°

, pressingly engages the interior surface of the barrel and the confronting surfaces of the shank webs to force other webs of the shank into binding contact with the annular lip of the barrel.

15. In a syringe having a barrel and a plunger moveable axially in the barrel:

locking means for locking the plunger to the barrel and including cam means carried by the barrel between the barrel and plunger, the cam means having a camming surface of such shape that the intersection of the cam surface with a plane normal to the direction of travel of the plunger defines a closed curve having a segment that is generally circular and has a substantially constant radius, and another segment that extends outwardly substantially beyond the locus of points generated by such radius, and means for rotating the cam means to force the plunger into binding contact between the cam means and the barrel.

16. The device of claim 15 wherein the length of the maximum length chord across the closed curve is at least about 1.2 times the length of the longest chord across the closed curve taken perpendicular to said chord of maximum length.

17. In a syringe having a barrel with a smooth, cylindrical interior surface and having an open proximal end defined by an internally extending annular lip, and a plunger moveable axially in the barrel and having a shank comprising radially and axially extending webs spaced angularly from one another;

locking means for locking the plunger to the barrel and including cam means carried between two adjacent webs of the plunger and the interior surface of the barrel, the cam means having a camming surface configured so that the intersection of the camming surface with a plane normal to the direction of travel of the plunger defines a closed curve having a first segment that is generally circular and has a substantially constant radius, a second segment formed on a larger radius approximating the radius of the cylindrical inner surface of the barrel, and a third segment extending between the first and second segments, at least a portion of the third segment extending substantially beyond the locus of points generated by the radius of the first segment, the cam means being rotatable from a first, unlocked position permitting substantially free movement of the plunger axially within the barrel, and a second, locked position in which said camming surface contacts the inner wall of the barrel and the walls of said adjacent webs to urge the plunger into binding contact between the camming surface and the annular lip of the barrel.