Compact syringe

Claim 2

A syringe for dispensing a liquid medicament, comprising: hollow cylindrical barrel means having a closed axial end and an open axial end; elastomeric piston means sealingly and slidably disposed within said barrel means for movement lengthwise thereof, said piston means having a central opening therethrough in a direction substantially parallel with the direction of movement of said piston means; closure means yieldably obstructing the flow of liquid from said barrel means, said closure means comprising a membrane integral with said piston means and extending across said openIng, said membrane having a slit therethrough; elongated rod means having an end portion adjacent one end thereof extending into and firmly held within said opening in said piston means, said rod means having a central passageway therethrough and being longer than said barrel means, whereby said rod means projects outwardly through the open axial end of said barrel means; one-way gripping means coacting between said end portion and said piston means 1. for preventing relative rotation between said end portion and said piston means in one rotational direction to thereby permit rotation of the rod means and the piston means relative to the barrel means to break loose any seizing that may occur between the piston means and the barrel means and 2. for permitting axial insertion of said end portion into said opening of said piston means while preventing said end portion from being axially separated from said piston means; said oneway gripping means including projection means fixed to said end portion and projecting radially outwardly therefrom for distorting the portion of said piston means defining the opening therethrough, the axial end face of said projection means which faces away from the other end of said rod means being formed with an inclined surface thereon which slopes downwardly and outwardly toward said other end of said rod means to facilitate axial insertion of said rod means into the opening formed in said piston means, the other axial end face of said projection means extending outwardly substantially radially relative to the longitudinal axis of said rod means for preventing said rod means from being axially separated from said piston means; and laterally projecting grip means on said rod means near the other end thereof.

Claim 3

for permitting axial insertion of said end portion into said opening of said piston means while preventing said end portion from being axially separated from said piston means; said one-way gripping means including projection means fixed to said end portion and projecting radially outwardly therefrom for distorting the portion of said piston means defining the opening therethrough, the axial end face of said projection means which faces away from the other end of said rod means being formed with an inclined surface thereon which slopes downwardly and outwardly toward said other end of said rod means to facilitate axial insertion of said rod means into the opening formed in said piston means, the other axial end face of said projection means extending outwardly substantially radially relative to the longitudinal axis of said rod means for preventing said rod means from being axially separated from said piston means; and laterally projecting grip means on said rod means near the other end thereof.

Claim 4

for permitting axial insertion of said end portion into said opening of said piston means while preventing said end portion from being axially separated from said piston means; said one-way gripping means including projection means fixed to said end portion and projecting radially outwardly therefrom for distorting the portion of said piston means defining the opening therethrough, the axial end face of said projection means which faces away from the other end of said rod means being formed with an inclined surface thereon which slopes downwardly and outwardly toward said other end of said rod means to facilitate axial insertion of said rod means into the opening formed in said piston means, the other axial end face of said projection means extending outwardly substantially radially relative to the longitudinal axis of said rod means for preventing said rod means from being axially separated from said piston means; and laterally projecting grip means on said rod means near the other end thereof.

Claim 5

A syringe according to claim 1, including elongated cannula means having one end thereof connected to the other end of said rod means and communicating with the passageway therethrough, said cannula means including a sleeve portion of enlarged inside and outside diameter adjacent said rod means, said inside diameter diverging toward said rod means, and said sleeve portion including a flange fixed adjacent the free end thereof and projecting outwardly therefrom; wherein said rod means has a substantially cylindrical portion at the other end thereof, said cylindrical portion converging toward said cannula means for snug frictional engagement within the inside diameter of said sleeve portion; wherein said rod means has a sleeve part at said other end thereof disposed outwardly from and positioned in surrounding relationship to said cylindrical portion for defining an annular space therebetween, said sleeve part having the inside surface thereof formed with groove means thereon, said sleeve portion of said cannula means projecting into said annular space with said flange being engaged within the groove means for fixedly securing said cannula means to said rod means; wherein said sleeve portion of said cannula means is axially longer than said sleeve part so that a portion of said sleeve portion projects outwardly beyond the free end of said sleeve part when said cannula means is mounted on said rod means; and elongated sheath means closed at one end and open at the other end for sealingly enclosing and surrounding said cannula means, the inside surface of said sheath means adjacent said other end being snugly and slidably engagable with the external surface of said sleeve portion where same projects outwardly beyond said sleeve part.

Claim 6

A syringe according to claim 1, wherein said projection means includes an annular flange fixed to and surrounding said end portion and projecting radially outwardly therefrom, and wherein said one-way gripping means also includes a plurality of circumferentially spaced projections fixed to said end portion and projecting radially outwardly therefrom for distorting the portion of said piston means defining the opening therethrough, said projections Being axially spaced from said annular flange and including a substantially radially directed face on one side thereof and a sloped face extending inwardly from the outer end of said radial face to the outer periphery of said end portion, whereby said projections effectively prevent rotation between said piston means and said rod means only in said one rotational direction.

Claim 7

A syringe for dispensing a liquid medicament, comprising; hollow cylindrical barrel means having a closed axial end and an open axial end; elastomeric piston means sealingly and slidably disposed within said barrel means for movement lengthwise thereof, said piston means having a central opening therethrough in a direction substantially parallel with the direction of movement of said piston means; closure means yieldably obstructing the flow of liquid from said barrel means, said closure means comprising a membrane integral with said piston means and extending across said opening, said membrane having a slit therethrough; elongated rod means having an end portion adjacent one end thereof extending into and firmly held within said opening in said piston means, said rod means having a central passageway therethrough and being longer than said barrel means, whereby said rod means projects outwardly through the open axial end of said barrel means; one-way gripping means coacting between said end portion and said piston means for preventing relative rotation therebetween in one rotational direction, thereby permitting rotation of the rod means and the piston means relative to the barrel means to break loose any seizing that may occur between the piston means and the barrel means; and said one-way gripping means includes a plurality of circumferentially spaced projections fixed to said end portion and projecting radially outwardly therefrom for distorting the portion of said piston means defining the opening therethrough, said projections including a substantially radially directed face on one side thereof and a sloped face extending inwardly from the outer end of said radial face to the outer periphery of said end portion, whereby said projections effectively prevent relative rotation between said piston means and said rod means only in said one rotational direction; the axial end face of each said projection which faces away from the other end of said rod means being formed with an inclined surface thereon which slopes downwardly and outwardly toward said other end of said rod means to facilitate insertion of said rod means into the opening formed in said piston means, the other axial end face of each said projection extending outwardly in a substantially radial plane relative to the longitudinal axis of said rod means for preventing said rod means from being axially separated from said piston means; and laterally projecting grip means on said rod means near the other end thereof.

Claim 8

A syringe for dispensing a liquid medicament, comprising; hollow cylindrical barrel means having a closed axial end and an open axial end; elastomeric piston means sealingly and slidably disposed within said barrel means for movement lengthwise thereof, said piston means having a central opening therethrough in a direction substantially parallel with the direction of movement of said piston means; closure means yieldably obstructing the flow of liquid from said barrel means, said closure means comprising a membrane integral with said piston means and extending across said opening, said membrane having a slit therethrough; elongated rod means having an end portion adjacent one end thereof extending into and firmly held within said opening in said piston means, said rod means having a central passageway therethrough and being longer than said barrel means, whereby said rod means projects outwardly through the open axial end of said barrel means; one-way gripping means coacting between said end portion and said piston means for preventing relative rotation therebetween in one rotational direction, thereby permitting rotation of the rod means and the piston means relative to the barrel means to break loose any seizing that may occur between the piston means and the barrel means; and said one-way gripping means includes a plurality of circumferentially spaced projections fixed to said end portion and projecting radially outwardly therefrom for distorting the portion of said piston means defining the opening therethrough, said projections including a substantially radially directed face on one side thereof and a sloped face extending inwardly from the outer end of said radial face to the outer periphery of said end portion, whereby said projections effectively prevent relative rotation between said piston means and said rod means only in said one rotational direction; the axial end face of each said projection which faces away from the other end of said rod means being formed with an inclined surface thereon which slopes downwardly and outwardly toward said other end of said rod means to facilitate insertion of said rod means into the opening formed in said piston means, the other axial end face of each said projection extending outwardly in a substantially radial plane relative to the longitudinal axis of said rod means for preventing said rod means from being axially separated from said piston means; and laterally projecting grip means on said rod means near the other end thereof.