Syringe shield

Claim 2

A syringe comprising: a barrel having an hypodermic needle mounted on one end thereof, a piston mounted for movement longitudinally within the barrel and connected to a handle that projects from the opposite end of said barrel; wherein said barrel is tubular and at least partially transparent in a portion that extends over the major part of its length; a tubular sleeve dimensioned to fit over the barrel, and guided to slide axially thereon between an extended position wherein it projects from said one end of the barrel beyond the tip of said needle and a retracted position wherein it coaxially surrounds said barrel and exposes said needle for use, said sleeve having a length that corresponds to that of said barrel and comprising a tubular wall that is at least partially transparent such that in said retracted position it affords unimpeded visibility of substantially the entire length of said transparent portion of said barrel; retaining means to secure said sleeve when in the retracted position, said retaining means being effective to prevent any inadvertent axial or rotational movement of said sleeve relative to said barrel; and locking means for securely and non-releasably locking the sleeve in said extended position, in which position the needle is fully covered to prevent injury to a user by the needle.

Claim 3

A syringe as claimed in claim 1 wherein said sleeve has an internal projection and said locking means comprise walls that define a locking recess in said barrel into which recess said projection can be positioned by predetermined angular movement of said sleeve relative to said barrel in said extended position, said barrel including an inclined ramp that approaches said locking recess to guide and facilitate entry of said projection unto said recess.

Claim 4

A syringe as claimed in claim 1, comprising a projection on the inside of the sleeve, and guide means on the outside of the barrel to guide the sleeve for axial movement from said retracted position to said extended position, said projection in the extended position being in register with a peripherally extending inclined ramp that terminates in a recess that comprises said locking means and is dimensioned to accommodate and non-releasably retain the projection, so that by resilient deflection said projection is movable over said ramp upon rotation of said sleeve and drops into the recess to lock the sleeve in the extended position.

Claim 5

A syringe as claimed in claim 1 wherein said sleeve is of molded plastic material and the cylindrical wall thereof is of substantially constant thickness.

Claim 6

A syringe comprising: a barrel having an hypodermic needle mounted on one end thereof said needle including a tip portion, a piston mounted for movement longitudinally within the barrel and connected to a handle that projects from an opposite end of said barrel; wherein said barrel is tubular; a tubular sleeve dimensioned to fit over the barrel, and mounted to slide axially thereon between an extended position wherein at least a portion of said tubular sleeve projects from said one end of the barrel beyond the tip portion of said needle and a retracted position wherein said tubular sleeve coaxially surrounds said barrel and exposes said needle for use, said sleeve including an internal projection; locking means for securely locking said sleeve in said extended position in which said needle is fully covered to prevent injury to a user by said needle, said locking means comprising walls on said barrel that define a locking recess in said barrel into which locking recess said internal projection can be positioned by predetermined rotational movement of said sleeve relative to said barrel in said extended position, said barrel including a radially inclined ramp adjacent one of said walls of said locking means to guide and facilitate entry of said projection into said locking recess by said predetermined rotational movement of said sleeve relative to said barrel in said extended position; and retaining means to releasably secure said sleeve when in the retracted position against axial movement relative to said barrel.

Claim 7

A syringe comprising: a barrel having an hypodermic needle mounted on one end thereof said needle including a tip portion, a piston mounted for movement longitudinally within the barrel and connected to a handle that projects from an opposite end of said barrel; wherein said barrel is tubular; a tubular sleeve dimensioned to fit over the barrel, and mounted to slide axially thereon between an extended position wherein at least a portion of said tubular sleeve projects from said one end of the barrel beyond the tip portion of said needle and a retracted position wherein said tubular sleeve coaxially surrounds said barrel and exposes said needle for use, said sleeve including an internal projection; locking means for securely locking said sleeve in said extended position in which said needle is fully covered to prevent injury to a user by said needle, said locking means comprising walls on said barrel that define a locking recess in said barrel into which locking recess said internal projection can be positioned by predetermined rotational movement of said sleeve relative to said barrel in said extended position, said barrel including a radially inclined ramp adjacent one of said walls of said locking means to guide and facilitate entry of said projection into said locking recess by said predetermined rotational movement of said sleeve relative to said barrel in said extended position; and retaining means to releasably secure said sleeve when in the retracted position against axial movement relative to said barrel.

Claim 8

A syringe as claimed in claim 5 wherein said retaining means comprises a screw-thread formed on an end portion of said sleeve and engageable with a complimentary screw-thread formed on said barrel when said sleeve is in the retracted position to retain said sleeve against inadvertent axial or rotational movement.

Claim 9

A syringe as claimed in claim 5, further comprising a guide means on the outside of the barrel to guide the sleeve for axial movement from said retracted position to said extended position, said internal projection in the extended position being in register with said extending inclined ramp terminating at said locking recess which is dimensioned to accommodate and nonreleasably retain said internal projection, whereby, said projection is resiliently deflected as said projection is moved over said ramp upon rotation of said sleeve, until said projection drops into said locking recess to lock said sleeve in the extended position.

Claim 10

A syringe as claimed in claim 7 wherein said retaining means comprises a screw-thread formed on an end portion of said sleeve and engageable with a mating screw-thread formed on said barrel when said sleeve is in the retracted position to retain said sleeve against inadvertent axial or rotational movement.

Claim 11

A syringe as claimed in claim 8 wherein the rotation of said sleeve to effect full engagement of said screw-threads amounts to approximately one quarter of a full rotation.

Claim 12

A syringe as claimed in claim 9 comprising a screw-threaded cap engageable with said screw-thread on said sleeve when the latter is in the extended condition to completely close the associated end of the sleeve.

Claim 13

A medical device comprising: a barrel having a hypodermic needle mounted on one end thereof, said hypodermic needle including a tip portion, said barrel being of cylindrical form over a portion of its length; a sleeve dimensioned to fit over said barrel, and mounted to be slidable between an extended position wherein said sleeve projects from said one end of said barrel beyond the tip portion of said needle and a retracted position wherein said sleeve coaxially surrounds said barrel and exposes said needle for use; locking means for securely locking said sleeve in said extended position in which said needle is fully covered to prevent injury to a user by said needle, said locking means comprising walls that define a locking recess in said barrel into which recess said internal projection can be positioned by predetermined movement of said sleeve relative to said barrel in said extended position, said barrel including an inclined ramp that approaches said locking recess to guide and facilitate entry of said projection into said recess; and a retaining means to releasably secure said sleeve when in said retracted position against axial movement relative to said barrel.

Claim 14

A medical device comprising: a barrel having a hypodermic needle mounted on one end thereof, said hypodermic needle including a tip portion, said barrel being of cylindrical form over a portion of its length; a sleeve dimensioned to fit over said barrel, and mounted to be slidable between an extended position wherein said sleeve projects from said one end of said barrel beyond the tip portion of said needle and a retracted position wherein said sleeve coaxially surrounds said barrel and exposes said needle for use; locking means for securely locking said sleeve in said extended position in which said needle is fully covered to prevent injury to a user by said needle, said locking means comprising walls that define a locking recess in said barrel into which recess said internal projection can be positioned by predetermined movement of said sleeve relative to said barrel in said extended position, said barrel including an inclined ramp that approaches said locking recess to guide and facilitate entry of said projection into said recess; and a retaining means to releasably secure said sleeve when in said retracted position against axial movement relative to said barrel.

Claim 15

A medical device comprising: a barrel having a hypodermic needle mounted on one end thereof, said hypodermic needle including a tip portion, said barrel being of cylindrical form over the major portion of its length; a sleeve dimensioned to fit over said barrel, and mounted to be slidable there along, said sleeve being movable axially between an extended position wherein it projects from said one end of said barrel beyond the tip portion of said needle and a retracted position wherein it coaxially surrounds said barrel and exposes said needle for use; a projection on the inside of said sleeve, a mating groove extending along the outside of said barrel, an inclined ramp extending transversely from said groove and terminating in a recess that comprises locking means for securely locking said sleeve in said extended position in which said needle is fully covered to prevent injury to a user by said needle, said recess being dimensioned to accommodate and retain said projection, said projection being movable along said groove as said sleeve is moved axially along said barrel until said projection registers with said ramp, further rotational movement of said sleeve causing said projection to move up said ramp and then to drop into said recess to lock said sleeve in the extended position; and retaining means to releasably secure said sleeve when in said retracted position against axial movement relative to said barrel.

Claim 16

A medical device comprising: a barrel having a hypodermic needle mounted on one end thereof, said hypodermic needle including a tip portion, said barrel being of cylindrical form over the major portion of its length; a sleeve dimensioned to fit over said barrel, and mounted to be slidable there along, said sleeve being movable axially between an extended position wherein it projects from said one end of said barrel beyond the tip portion of said needle and a retracted position wherein it coaxially surrounds said barrel and exposes said needle for use; a projection on the inside of said sleeve, a mating groove extending along the outside of said barrel, an inclined ramp extending transversely from said groove and terminating in a recess that comprises locking means for securely locking said sleeve in said extended position in which said needle is fully covered to prevent injury to a user by said needle, said recess being dimensioned to accommodate and retain said projection, said projection being movable along said groove as said sleeve is moved axially along said barrel until said projection registers with said ramp, further rotational movement of said sleeve causing said projection to move up said ramp and then to drop into said recess to lock said sleeve in the extended position; and retaining means to releasably secure said sleeve when in said retracted position against axial movement relative to said barrel.

Claim 17

A medical device as claimed in claim 12 wherein said retaining means comprises a screw-thread formed on an end portion of said sleeve and engageable with a mating screw-thread formed on said barrel when said sleeve is in the retracted position to releasably secure said sleeve against axial movement, said groove having a circumferential extension to accommodate said projection during rotation of said sleeve upon engagement or disengagement of said mating screw threads.

Claim 18

A medical device as claimed in claim 13 wherein the rotation of said sleeve to effect full engagement of said screw-threads of said sleeve to effect full engagement of said screw-threads amounts to approximately one quarter of a full rotation.

Claim 19

A medical device as claimed in claim 14 further comprising a screw-threaded cap engageable with said screw-thread on said sleeve when the latter is in the extended condition to completely close the associated end of the sleeve.

Claim 20

A medical device comprising: a tubular barrel having a hypodermic needle coaxially mounted at a distal end thereof, said hypodermic needle including a tip; a sleeve dimensioned to fit over said barrel and mounted to be axially movable there along between an extended position wherein said needle tip is covered and a retracted position wherein said needle tip is exposed; a projection on the inside of said sleeve, a mating groove extending axially along the outside of said barrel, an inclined ramp extending transversely from said groove and terminating in a wall projecting from said barrel, said projection being axially movable along said groove from said retracted position in response to axial movement of said sleeve along said barrel until said projection is aligned with said ramp, said projection then being rotatably movable relative to said barrel in response to rotational movement of said sleeve relative to said barrel to move said projection along said inclined ramp to a position atop said wall, continued rotational movement of said sleeve relative to said barrel causing said projection to move from atop said wall to a position behind said wall.

Claim 21

A medical device comprising: a tubular barrel having a hypodermic needle coaxially mounted at a distal end thereof, said hypodermic needle including a tip; a sleeve dimensioned to fit over said barrel and mounted to be axially movable there along between an extended position wherein said needle tip is covered and a retracted position wherein said needle tip is exposed; a projection on the inside of said sleeve, a mating groove extending axially along the outside of said barrel, an inclined ramp extending transversely from said groove and terminating in a wall projecting from said barrel, said projection being axially movable along said groove from said retracted position in response to axial movement of said sleeve along said barrel until said projection is aligned with said ramp, said projection then being rotatably movable relative to said barrel in response to rotational movement of said sleeve relative to said barrel to move said projection along said inclined ramp to a position atop said wall, continued rotational movement of said sleeve relative to said barrel causing said projection to move from atop said wall to a position behind said wall.

Claim 22

A medical device comprising: a barrel having a hypodermic needle mounted on a distal end thereof, said hypodermic needle including a distal tip portion; a sleeve dimensioned to fit over said barrel, and mounted to be slidable there along, said sleeve being axially between an extended position wherein said sleeve projects from said distal end of said barrel beyond the tip portion of said needle and a retracted position wherein said sleeve exposes the tip portion of said needle for use; locking means for securely locking said sleeve in said extended position; securing means comprising a screw-thread formed on said sleeve near a distal end thereof and engageable with a mating screw-thread formed on said barrel near said distal end of said barrel when said sleeve is in the retracted position to releasably secure said sleeve against axial movement.

Claim 23

A medical device comprising: a barrel having a hypodermic needle mounted on a distal end thereof, said hypodermic needle including a distal tip portion; a sleeve dimensioned to fit over said barrel, and mounted to be slidable there along, said sleeve being axially between an extended position wherein said sleeve projects from said distal end of said barrel beyond the tip portion of said needle and a retracted position wherein said sleeve exposes the tip portion of said needle for use; locking means for securely locking said sleeve in said extended position; securing means comprising a screw-thread formed on said sleeve near a distal end thereof and engageable with a mating screw-thread formed on said barrel near said distal end of said barrel when said sleeve is in the retracted position to releasably secure said sleeve against axial movement.

Claim 24

A medical device according to claim 17 further including a screw-threaded cap engageable with said screw-thread on said sleeve when the latter is in the extended position to completely close the distal end of said sleeve.

Claim 25

A medical device as claimed in claim 17 wherein the rotation of said sleeve to effect full engagement of said screw-threads amounts to approximately one quarter of a full rotation.

Claim 26

A medical device as claimed in claim 18 wherein said screw-threaded cap includes means for preventing puncturing of said cap by said needle.

Claim 27

A syringe comprising: a barrel having an hypodermic needle mounted on one end thereof said needle that projects from an opposite end of said barrel; wherein said barrel is tubular; a tubular sleeve dimensioned to fit over the barrel, and mounted to slide axially thereon between an extended position wherein at least a portion of said tubular sleeve projects from said one end of the barrel beyond the tip portion of said needle and a retracted position wherein said tubular sleeve coaxially surrounds said barrel and exposes said needle for use, said sleeve including an internal projection; locking means for securely locking said sleeve in said extended position in which said needle is fully covered to prevent injury to a user by said needle, said locking means comprising walls on said barrel that define a locking recess in said barrel into which locking recess said internal projection can be positioned by predetermined movement of said sleeve relative to said barrel in said extended position, said barrel including an inclined ramp adjacent one of said walls of said locking means to guide and facilitate entry of said projection into said locking recess by said predetermined movement of said sleeve relative to said barrel in said extended position; and retaining means to releasably secure said sleeve when in the retracted position against axial movement relative to said barrel.

Claim 28

A syringe comprising: a barrel having an hypodermic needle mounted on one end thereof said needle that projects from an opposite end of said barrel; wherein said barrel is tubular; a tubular sleeve dimensioned to fit over the barrel, and mounted to slide axially thereon between an extended position wherein at least a portion of said tubular sleeve projects from said one end of the barrel beyond the tip portion of said needle and a retracted position wherein said tubular sleeve coaxially surrounds said barrel and exposes said needle for use, said sleeve including an internal projection; locking means for securely locking said sleeve in said extended position in which said needle is fully covered to prevent injury to a user by said needle, said locking means comprising walls on said barrel that define a locking recess in said barrel into which locking recess said internal projection can be positioned by predetermined movement of said sleeve relative to said barrel in said extended position, said barrel including an inclined ramp adjacent one of said walls of said locking means to guide and facilitate entry of said projection into said locking recess by said predetermined movement of said sleeve relative to said barrel in said extended position; and retaining means to releasably secure said sleeve when in the retracted position against axial movement relative to said barrel.