Other

Katumi Tominaga

Seiji Kojima

Hiromu Miura

Shigeo Hayashi

Kazuhide Yamazaki

Junichi Kiyatake

A first sensor ( - ), the mounting position of the first sensor ( - ) being recognized as a counting number of instruction pulses to a pulse motor ( ), is arranged along a plate ( ) with slits of an encoder at a portion between a position where a pushing holder ( ) is connected to a plunger ( ) for the liquid infusion, and a start position where the pushing holder ( ) is separated from the plunger ( ). A counting means ( ) for counting encoder pulses from the encoder, is reset when a first sensor ( - ) is detected by a position detecting device ( ) moved together with the pushing holder ( ), and started to count the encoder pulses according to the movement of the pushing holder ( ). A time to complete the liquid infusion is calculated by using a distance between the position where the plunger ( ) is connected to the holder ( ) and a liquid infusion finish position proper to the syringe, and a predetermined liquid infusion speed.

Liquid infusion apparatus

A liquid infusion apparatus for fixing an outer cylinder of a syringe and a driver for pushing a plunger in a predetermined direction so as to exhaust liquid in the syringe, an incremental linear encoder arranged along the feeding axis of said driver for pushing the plunger, a detector of said incremental linear encoder mounted on a slider portion of the driver for pushing the plunger so as to generate a signal indicating a moving quantity of the plunger, and a sensor provided in the vicinity of a liquid exhaust port of the outer cylinder for setting along the feeding axis a remaining liquid quantity small section so as to generate a signal about a position of the plunger at the remaining liquid quantity small section.

In a liquid infusion apparatus, an incremental linear encoder is arranged along the feeding shaft direction of the liquid infusion apparatus to directly monitor the movement and position of a carriage part which applies an action to a plunger. A detecting sensor is provided at a starting point of a remaining liquid quantity small region to recognize the absolute position at said region by using feed-back pulses from said encoder. A pressing device for pressing a flange of the plunger to a plunger receiving portion of a slider by holding arms is provided. A pressure sensor is arranged between said plunger receiving portion and the slider to detect a negative pressure applied to the plunger in such a manner that the other operation states of pressure are detected based on a detected value of pressure at which the flange is pressed to the plunger receiving portion. The holding arms which are able to open are moved in the moving direction of the slider to press for holding the flange of the plunger to the plunger holding portion of the slider. The holding arm for press holding the flange of the plunger with the slider is supported rotatably freely by a shaft and urged to rotate by a spring in the clockwise direction. A projection which is engaged with a small projection provided an end of the holding arms is provided on a lever, so that the holding arm can be rotated in the counter-clockwise direction by said projection. A half-nut releasing device interlocking with a retracting lever provided on the slider for disengaging the half-nut from a feed screw is composed of means to urge the half-nut by a release cam having a step portion and of means to press the flange of the plunger against the slider by the holding arm for holding the flange of the plunger. A one-way clutch for transmitting a driving force in the syringe pushing direction is arranged between the output shaft of a prime mover and the feed screw.

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Saitama, Japan

Katumi Tominaga