Dental spray hand piece

In a dental spray hand piece comprising at least one agent leading through a housing of the hand piece and terminating in a spray nozzle, valve means in the housing of the hand piece for each agent line for controlling the flow of agent in said line, each of said valve means comprising a pressure member movable from a first position pinching the agent line closed to stop flow therethrough to a second position allowing flow therethrough, a rocker arm mounted for pivotal movement on a shaft in said housing, means biasing the rocker arm to a first position holding the pressure member in said first position, a purchase engaging said rocker arm while in said first position and shifting the rocker arm toward a second position allowing the pressure member to move to said second position, the improvement comprising means for preventing dripping when the valve means closes the flow in said line, said means creating a suction in the line between the valve and the end of the nozzle to draw an agent in the line inward from said end, said means for preventing including at least a portion of each agent line extending between the nozzle and the valve means being a hose section of elastic material, said hose section having a cross-section greater than the cross-section of the flow passing through the agent line when in an open state, said pressure member of the valve means acting on a segment of the hose section, said segment of the hose section being received in a channel having side walls limiting lateral movement of said segment as the pressure member engages said segment to stop the flow therethrough, and a thrust piece mounted on said shaft for pivotal movement and engaging said rocker arm, said thrust piece being engageable with the hose section between the pressure member of the valve means and the spray nozzle so that when the purchase is actuated, the rocker arm moves the thrust piece to partially deform the hose section to the cross-section of the flow through said valve.

In a dental spray hand piece comprising at least one agent line leading through a housing of the hand piece and terminating in a spray nozzle, valve means in the housing of the hand piece for controlling the flow of the agent in each of said lines, said valve means including a rocker arm mounted for pivotal movement on an edge of said housing and having a projection engaging a portion of the agent line, means biasing the rocker arm to a first position with said projection pinching the agent line closed and a purchase engaging an opposite end of the rocker arm and being movable by actuation of an operator to move the rocker to a second position releasing the pinching force on the agent line, the improvements comprising means for preventing dripping of the agent from the end of the nozzle when the valve means closes flow in said line, said means for preventing including at least a portion of each agent line extending between the nozzle and the valve means being a hose section of elastic material, said hose section having a cross-section greater than the cross-section of the flow through the valve means when the rocker arm is in said second position, and a thrust piece engaging a portion of said hose section between the valve means and the nozzle and having a portion engaging the rocker arm so that movement of the rocker arm toward said second position to allow flow through the agent line causes said thrust piece to partially deform the hose section to the cross-section of the flow through said agent line when said rocker arm is in said second position.