Mixing syringe

Claim 2

A syringe for mixing and dispensing a material formed from several components which are mixed together before the material is used, comprising: a hollow housing adapted to engage and hold a cup containing the material components; a hollow piston slidably mounted within the housing; a shaft slidably mounted in and extending from a first end of the piston; a mixing member; and a mounting means secured to the mixing member and slidably mounted in the piston in contact with the shaft whereby linear movement of the shaft into the piston drives the mixing plate from a retracted position against a second end of the piston into the mixing cup and through the material components, the mounting means including rotary means coupled to the piston and operative to rotate the mixing member when the shaft is moved linearly, the piston and retracted mixing plate being movable as a unit with respect to the housing to force the material through the cup after mixing is complete.

Claim 3

The syringe defined in claim 1 in which the mounting means is rotationally free with respect to the shaft whereby rotation of the mixing plate does not cause shaft rotation as the shaft is moved linearly.

Claim 4

The syringe defined in claim 2 and further comprising a return spring disposed between the piston and mounting means to urge the mixing member into a retracted position.

Claim 5

The syringe defined in claim 3 in which the mixing member is a slotted disk, and in which the rotary means and piston include mated helically threaded portions for rotating the disk.

Claim 6

A syringe for mixing and dispensing compositions such as a dental impression material prepared from several components which are blended just before the material is to be used, comprising: a cup for holding the material components and having an open end and a capped end with a releasable closure; a hollow housing releasably engaged with the cup over the open end thereof; a piston slidably fitted in and extending out of the housing aWay from the cup, the piston having an inner end extending into the cup when the piston is moved toward the capped end; a mixing plate disposed between the inner end of the piston and the capped end of the cup; a mounting means secured to the mixing plate and movably mounted on the piston so linear movement of the mounting means moves the mixing plate from a retracted position against the inner end of the piston to an extended position adjacent the capped end of the cup, the mounting means including rotary means coupled to the piston and operative to cause rotation of the mixing plate as it is moved between the retracted and extended position; and a shaft slidably mounted on the piston in contact with the mounting means, and extending from an outer end of the piston to be linearly movable to drive the mounting means and mixing plate, the shaft and mounting means being rotationally free with respect to each other whereby mixing-plate rotation induced by the rotary means is isolated from the linearly movable shaft.

Claim 7

A syringe for mixing and dispensing compositions such as a dental impression material prepared from several components which are blended just before the material is to be used, comprising: a cup for holding the material components and having an open end and a capped end with a releasable closure; a hollow housing releasably engaged with the cup over the open end thereof; a piston slidably fitted in and extending out of the housing aWay from the cup, the piston having an inner end extending into the cup when the piston is moved toward the capped end; a mixing plate disposed between the inner end of the piston and the capped end of the cup; a mounting means secured to the mixing plate and movably mounted on the piston so linear movement of the mounting means moves the mixing plate from a retracted position against the inner end of the piston to an extended position adjacent the capped end of the cup, the mounting means including rotary means coupled to the piston and operative to cause rotation of the mixing plate as it is moved between the retracted and extended position; and a shaft slidably mounted on the piston in contact with the mounting means, and extending from an outer end of the piston to be linearly movable to drive the mounting means and mixing plate, the shaft and mounting means being rotationally free with respect to each other whereby mixing-plate rotation induced by the rotary means is isolated from the linearly movable shaft.

Claim 8

The syringe defined in claim 5 and further comprising a return spring disposed between the piston and mounting means, and operative to urge the mixing plate toward the retracted position.

Claim 9

The syringe defined in claim 6 in which the housing and piston each have handles extending therefrom, the mixing plate is a disk with a plurality of apertures therethrough, the mounting means includes a tube rigidly secured to the mixing-plate disk and slidably mounted on the piston, the shaft being received in the tube in linear driving relationship, and the rotary means comprises a threaded follower rigidly secured to the tube, the piston having a threaded portion receiving the follower whereby the follower, tube and disk are rotated as the tube is linearly driven by the shaft.

Claim 10

The syringe defined in claim 5 in which the housing and piston each have handles extending therefrom, and the shaft includes a knob at its outer end, whereby mixing is performed by gripping the syringe to reciprocate the knob with respect to the piston handle, and dispensing of the mixed material is performed by removing the cup closure and drawing the housing and piston handles together to drive the piston and retracted mixing plate into the cup to expel material therefrom.

Claim 11

The syringe defined in claim 5 in which the mounting means includes a hollow tube having a closed end rigidly secured to the mixing plate, the piston defining a bore in which the tube is slidably fitted, and a ball disposed in the tube at the closed end, the shaft being fitted within the tube to bear against the ball, and further comprising a return spring disposed between the piston and mounting means to urge the mixing plate toward the retracted position.

Claim 12

The syringe defined in claim 9 in which the rotary means comprises a follower having external threads and being rigidly secured to the tube, the piston bore defining mating threads receiving the follower threads.

Claim 13

The syringe defined in claim 10 and further comprising a seal disposed around the tube and seated at the inner end of the piston.

Claim 14

The syringe defined in claim 5 in which the cup is generally cylindrical and the mixing plate is a circular disk having a diameter slightly smaller than an inside diameter of the cup, the disk including a plurality of apertures therethrough.