Infusion pump

Claim 1

An infusion pump for controllable long-term injection of solutions from a syringe, comprising: holding means for at least one syringe with a piston; actuating means for said piston of the syringe; electrical control drive means cooperating with said actuating means and having an electric battery for driving; retarding means connected to said actuating means; storage means for storing mechanical work acting on said actuating means through said retarding means in direction of said drive means; said electrical control drive means releasing said retarding means when switched on and actuating said retarding means when switched off, said electrical control drive means having an electric motor running under idling condition when in operative state, said motor experiencing a load condition only for a substantially brief interval when said motor is switched on, said motor providing energy for maintaining said pump in operation upon functional failure of said storage means, said motor operating under power in non-idling condition after failure of said storage means to reduce time of operation, a change in operating condition from idling to non-idling of said motor indicating failure of said storage means; said electric motor comprising a start-stop control, said motor having no current when stopped; said actuating means comprising a rod having a handle at a free end thereof; a housing for said pump; said rod having a metal region guided in said housing, one end of said rod having said handle and the other end of said rod actuating said piston of said syringe; said rod communicating with said storage means and said retarding means; said storage means comprising a spring; a worm wheel with a periphery driven by said electrical control drive means and having worm teeth on the periphery of said worm wheel, said electrical control drive means connected to said actuating means driving through said worm teeth; said worm wheel being parallel to said rod; a worm gear in mesh with said worm wheel and having an axis of rotation perpendicular to the axis of said rod and said worm wheel; said worm wheel having a pitch so that said worm wheel is self-locking for static friction and is free-running for sliding friction; said worm gear having free-wheeling action only in one direction of rotation which determines the pulling of said storage means, said worm gear being locked in the other direction of rotation; said worm gear having a ratchet wheel connected thereto and rotating with said worm gear; a spring-loaded pawl engaging said ratchet wheel; said pawl being releasable from outside said housing.