| 摘要 |
<p>An automatically controlled actuator is claimed for the piston of a medical injection syringe. The piston is moved by a stepped rotation electric motor through a mechanical transmission, e.g. comprising rack and pinion gear. In order to control the delivery d of the syringe, advantage is taken of the relationship of delivery to piston speed S and to physical characteristics of the syringe, partic. its full vol. capacity V and the pistons full stroke length L i.e. d=SV/L or S=d L/V The motor is driven by an oscillator of which the output frequency is proportional to two electrical values and inversely proportional to a third, all three values pref. being resistances. The first two values respectively represent d and L and the third V. These three electrical values are set manually to represent the required delivery, d, and the known characteristics of the syringe i.e. L and V. The circuit between the oscillator and the motor pref. comprises an electronic counter and an interface amplifier. The counter circuit pref. includes switching so that direction of rotation of the motor is reversible. The actuator is designed to operate medical injection syringes by automatically controlled displacement of piston(s). The actuator can be used for syringes of widely different physical characteristics, provided a specification of the characteristics is available.</p> |
