Piston valve syringe gun

Claim 2

In a syringe gun suitable for dispensing liquid or semiliquid, the combination of a barrel, a piston rod, a piston attached to said piston rod and located within said barrel for discharging the contents of said barrel therefrom, an inlet valve for enabling passage of liquid or semi-liquid into said barrel, and a discharge valve for enabling passage of liquid or semiliquid out of said barrel, wherein at least one of said valves is the combination of a chamber, said chamber having an inlet wall and said inlet wall defining an inlet orifice to said chamber, a resilient plate within said chamber of substantially greater cross-sectional area than said inlet orifice, said plate having an inlet side and an outlet side, a passage for liquid or semiliquid from said inlet side of said plate to said outlet side of said plate, said inlet wall and said plate each having a central area for enabling the sealing of said inlet orifice and each having a peripheral area, a support within said chamber abutting said outlet side of said plate, whereby the peripheral area of said inlet side of said plate is spaced apart from the peripheral area of said inlet wall, and an outlet wall to said chamber, said outlet wall defining an outlet orifice for enabling passage of liquid or semi-liquid from said chamber, at least one said central area projecting beyond its own peripheral area towards said other central area, whereby the central area of said inlet side of said resilient plate will be held against the central area of said inlet wall by said support to seal said inlet orifice and will flex away from said central area of said inlet wall under pressure upon said inlet side of said plate to permit the passage of liquid or semi-liquid through said inlet orifice and through said passage to said outlet orifice.

Claim 3

The combination defined in claim 1, wherein the cross-sectional area of said plate is the same as or is less than the internal cross-sectional area of said chamber, and wherein said plate is so shaped as to define at least one perforation in said peripheral area forming said passage whereby liquid or semi-liquid may pass from said inlet side of said plate to said outlet side of said plate.

Claim 4

The combination defined in claim 2, wherein said plate defines a plurality of perforations in said peripheral area of said plate, said perforations being symmetrically disposed within said plate, whereby liquid or semi-liquid may pass from said inlet side of said plate to said outlet side of said plate.

Claim 5

The combination defined in claim 1, wherein said inlet valve is the combination of a chamber, said chamber having an inlet wall and said inlet wall defining an inlet orifice to said chamber, a floating plate within said chamber of substantially greater cross-sectional area than said inlet orifice but smaller than the internal cross-sectional area of said chamber, said plate having an inlet side and an outlet side, a support within said chamber, a passage for liquid or semi-liquid from said inlet side of said plate to said outlet side of said plate, and an outlet wall to said chamber, said outlet wall defining an outlet orifice for enabling passage of liquid or semi-liquid from said chamber, whereby said plate will seal said inlet orifice under pressure upon said outlet side of said plate and will move from said inlet orifice under pressure upon said inlet side of said plate to abut said support to permit passage of liquid or semi-liquid through said inlet orifice, and through said passage to said outlet orifice, and wherein said discharge valve is the combination of a chamber, said chamber having an inlet wall and said inlet wall defining an inlet orifice to said chamber, a resilient plate within said chamber of substantially greater cross-sectional area than said outlet orifice, said plate having an Inlet side and an outlet side, a passage for liquid or semi-liquid from said inlet side of said plate to said outlet side of said plate, said inlet wall and said plate each having a central area for enabling the sealing of said inlet orifice and each having a peripheral area, a support within said chamber abutting said outlet side of said plate, whereby the peripheral area of said inlet side of said plate is spaced apart from the peripheral area of said inlet wall, and an outlet wall to said chamber, said outlet wall defining an outlet orifice for enabling passage of liquid or semi-liquid from said chamber, at least one said central area projecting beyond its own peripheral area towards said other central area, whereby the central area of said inlet side of said plate will be held against the central area of said inlet wall by said support to seal said inlet orifice and will flex away from said central area of said inlet wall under pressure upon said inlet side of said plate to permit the passage of liquid or semi-liquid through said inlet orifice and through said passsage to said outlet orifice.

Claim 6

The combination defined in claim 4, wherein said central area of said inlet wall is raised as a lip, whereby said central area of said inlet side of said resilient plate may seat against said lip to seal said inlet orifice.

Claim 7

The combination defined in claim 4, wherein the central area of said plate projects beyond its own peripheral area towards the central area of said inlet wall.

Claim 8

The combination as defined in claim 1, there being means for limiting the backward stroke of said piston to allow the entry of a predetermined quantity of liquid or semi-liquid into said barrel through said inlet valve.

Claim 9

The combination as defined in claim 1, wherein said inlet valve is integral with said piston.

Claim 10

The combination defined in claim 1, wherein said passage comprises castellations defining interposed recesses in said support whereby when said plate abuts said support liquid or semi-liquid may pass from said inlet side of said plate to said outlet side of said plate by way of said recesses between said castellations.

Claim 11

In a syringe gun suitable for dispensing liquid or semi-liquid, the combination of a barrel, a piston rod, a piston attached to said piston rod and located within said barrel for discharging the contents of said barrel therefrom, an inlet valve for enabling passage of liquid or semi-liquid into said barrel, and a discharge valve for enabling passage of liquid or semi-liquid out of said barrel, there being at least one ring of resilient material on the circumference of said piston whreby an air- and liquid-tight fit is provided between said piston and said barrel, wherein said inlet valve is integral with said piston and is the combination of a chamber, said chamber having an inlet wall and said inlet wall defining an inlet orifice to said chamber, a floating plate within said chamber of substantially greater cross-sectional area than said inlet orifice but smaller than the internal cross-sectional area of said chamber, said plate having an inlet side and an outlet side, a support within said chamber, a passage for liquid or semi-liquid from said inlet side of said plate to said outlet side of said plate, and an outlet wall to said chamber, said outlet wall defining an outlet orifice for enabling passage of liquid or semi-liquid from said chamber, whereby said plate will seal said inlet orifice under pressure upon said outlet side of said plate and will move from said inlet orifice under pressure upon said inlet side of said plate to abut said support to permit passage of liquid or semi-liquid through said inlet orifice, and through said passage to said outlet orifice.

Claim 12

In a syringe gun suitable for dispensing liquid or semi-liquid, the combination of a barrel, a piston rod, a piston attached to said piston rod and located within said barrel for discharging the contents of said barrel therefrom, an inlet valve for enabling passage of liquid or semi-liquid into said barrel, and a discharge valve for enabling passage of liquid or semi-liquid out of said barrel, there being at least one ring of resilient material on the circumference of said piston whreby an air- and liquid-tight fit is provided between said piston and said barrel, wherein said inlet valve is integral with said piston and is the combination of a chamber, said chamber having an inlet wall and said inlet wall defining an inlet orifice to said chamber, a floating plate within said chamber of substantially greater cross-sectional area than said inlet orifice but smaller than the internal cross-sectional area of said chamber, said plate having an inlet side and an outlet side, a support within said chamber, a passage for liquid or semi-liquid from said inlet side of said plate to said outlet side of said plate, and an outlet wall to said chamber, said outlet wall defining an outlet orifice for enabling passage of liquid or semi-liquid from said chamber, whereby said plate will seal said inlet orifice under pressure upon said outlet side of said plate and will move from said inlet orifice under pressure upon said inlet side of said plate to abut said support to permit passage of liquid or semi-liquid through said inlet orifice, and through said passage to said outlet orifice.

Claim 13

In a syringe gun suitable for dispensing liquid or semi-liquid, the combination of a barrel, said barrel having a front end and a rear end, a piston rod, a piston attached to said piston rod and located within said barrel for discharging the contents of said barrel therefrom uPon a forward stroke of said piston and said piston rod, said piston having a front face and a rear face, an inlet valve integral with said piston for enabling passage of liquid or semi-liquid into said barrel, a discharge valve for enabling passage of liquid or semi-liquid out of said barrel, and means for limiting the backward stroke of said piston to allow the entry of a predetermined quantity of liquid or semi-liquid into said barrel through said inlet valve, said means for limiting the backward stroke of said piston being the combination of two mutually abutting surfaces, the one surface being on said rear face of said piston and the other surface being on a sleeve held in a fixed but variable disposition relative to said barrel; wherein said inlet valve is the combination of a chamber, said chamber having an inlet wall and said inlet wall defining an inlet orifice to said chamber, a floating plate within said chamber of substantially greater cross-sectional area than said inlet orifice but smaller than the internal cross-sectional area of said chamber, said plate having an inlet side and an outlet side, a support within said chamber, a passage for liquid or semi-liquid from said inlet side of said plate to said outlet side of said plate, and an outlet wall to said chamber, said outlet wall defining an outlet orifice for enabling passage of liquid or semi-liquid from said chamber, whereby said plate will seal said inlet orifice under pressure upon said outlet side of said plate and will move from said inlet orifice under pressure upon said inlet side of said plate to abut said support to permit the passage of liquid or semi-liquid through said inlet orifice and through said passage and through said outlet orifice into said barrel; and wherein said discharge valve is the combination of a chamber, said chamber having an inlet wall and said inlet wall defining an inlet orifice to said chamber, a resilient plate within said chamber of substantially greater cross-sectional area than said inlet orifice, said plate having an inlet side and an outlet side, said inlet wall and said plate each having a central area for enabling the sealing of said inlet orifice and each having a peripheral area, a support within said chamber abutting said outlet side of said plate, whereby the peripheral area of said inlet side of said plate is spaced apart from the peripheral area of said inlet wall, a passage for liquid or semi-liquid from said inlet side of said plate to said outlet side of said plate, and an outlet wall to said chamber, said outlet wall defining an outlet orifice for enabling passage of liquid or semi-liquid from said chamber, at least one said central area projecting beyond its own peripheral area towards said other central area, whereby the central area of said inlet side of said plate is held against the central area of said inlet wall by said support to seal said inlet orifice and under pressure upon said inlet side of said plate will flex away from said central area of said inlet wall to permit the passage of liquid or semi-liquid through said inlet orifice through said passage and through said outlet orifice.

Claim 14

In a syringe gun suitable for dispensing liquid or semi-liquid, the combination of a barrel, said barrel having a front end and a rear end, a piston rod, a piston attached to said piston rod and located within said barrel for discharging the contents of said barrel therefrom uPon a forward stroke of said piston and said piston rod, said piston having a front face and a rear face, an inlet valve integral with said piston for enabling passage of liquid or semi-liquid into said barrel, a discharge valve for enabling passage of liquid or semi-liquid out of said barrel, and means for limiting the backward stroke of said piston to allow the entry of a predetermined quantity of liquid or semi-liquid into said barrel through said inlet valve, said means for limiting the backward stroke of said piston being the combination of two mutually abutting surfaces, the one surface being on said rear face of said piston and the other surface being on a sleeve held in a fixed but variable disposition relative to said barrel; wherein said inlet valve is the combination of a chamber, said chamber having an inlet wall and said inlet wall defining an inlet orifice to said chamber, a floating plate within said chamber of substantially greater cross-sectional area than said inlet orifice but smaller than the internal cross-sectional area of said chamber, said plate having an inlet side and an outlet side, a support within said chamber, a passage for liquid or semi-liquid from said inlet side of said plate to said outlet side of said plate, and an outlet wall to said chamber, said outlet wall defining an outlet orifice for enabling passage of liquid or semi-liquid from said chamber, whereby said plate will seal said inlet orifice under pressure upon said outlet side of said plate and will move from said inlet orifice under pressure upon said inlet side of said plate to abut said support to permit the passage of liquid or semi-liquid through said inlet orifice and through said passage and through said outlet orifice into said barrel; and wherein said discharge valve is the combination of a chamber, said chamber having an inlet wall and said inlet wall defining an inlet orifice to said chamber, a resilient plate within said chamber of substantially greater cross-sectional area than said inlet orifice, said plate having an inlet side and an outlet side, said inlet wall and said plate each having a central area for enabling the sealing of said inlet orifice and each having a peripheral area, a support within said chamber abutting said outlet side of said plate, whereby the peripheral area of said inlet side of said plate is spaced apart from the peripheral area of said inlet wall, a passage for liquid or semi-liquid from said inlet side of said plate to said outlet side of said plate, and an outlet wall to said chamber, said outlet wall defining an outlet orifice for enabling passage of liquid or semi-liquid from said chamber, at least one said central area projecting beyond its own peripheral area towards said other central area, whereby the central area of said inlet side of said plate is held against the central area of said inlet wall by said support to seal said inlet orifice and under pressure upon said inlet side of said plate will flex away from said central area of said inlet wall to permit the passage of liquid or semi-liquid through said inlet orifice through said passage and through said outlet orifice.

Claim 15

The combination defined in claim 11, wherein a base member has said rear end of said barrel firmly attached thereto, said base member defining a bore therein, and wherein said sleeve is located within said barrel and is held within said bore in said base member.

Claim 16

The combination defined in claim 12, wherein said bore in said base member is screw-threaded internally and wherein said sleeve is screw-threaded externally, whereby rotation of said sleeve within said bore will move said sleeve relative to said base member and to said barrel.