# US 4,380,801 A · Apparatus for measuring injection speed in injection molding machines

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- Number: US 4,380,801 A
- Document ID: US4380801A
- Status: Granted
- Kind: A
- Application number: 06/320,728
- Filed: 1981-11-12
- Granted: 1983-04-19
- Earliest claimed: 1979-02-07
- Assignees: Toshiba Kikai Kabushiki Kaisha
- Inventors: Noriyuki Motomura; Hiroyuki Tsuboi
- Web page: https://patentgrep.com/patent/US4380801A

## CPC

- G01P 3/66: using electric or magnetic means (G01P3/80 takes precedence; measuring short time intervals G04F8/00, G04F10/00)
- G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G})

## Abstract

In apparatus for measuring injection speed of an injection molding machine having a piston rod reciprocated by an injection cylinder of the injection molding machine, a plunger rod having, at an end thereof, a plunger tip slidably received in a plunger sleeve connected to a die, and a plunger coupling for interconnecting the plunger rod and the piston rod, the plunger coupling is provided with a projection. A proximity switch detects the projection while the plunger coupling moves. In accordance with the output of the proximity switch, the speed of the plunger coupling is computed.

## Claims

### Claim 1

An apparatus for measuring an injection speed in an injection molding machine having:
a piston rod reciprocated by an injection cylinder of the injection molding machine,
a plunger rod having, at one end thereof, a plunger tip slidably received in a plunger sleeve connected to a die, and
a plunger coupling for interconnecting the plunger rod and the piston rod,
the improvement in which the plunger coupling is provided with two projections with a recess formed therebetween, and which comprises:
a magnetic proximity switch for detecting said projection while the plunger coupling moves along the axis of the plunger rod and producing an output in accordance with the result of the detection, and
a means for computing in accordance with the output of said magnetic proximity switch, the speed of the plunger coupling, said computing means comprising means for producing pulses at a predetermined interval (T.sub.M), a gate circuit responsive to the output of said proximity switch for passing said pulses during the time interval after an edge of a first projection has passed said proximity switch and before a corresponding edge of a second projection passes said proximity switch, a pulse counter responsive to said output of said gate circuit for counting the number of pulses from said gate circuit, and a computing circuit responsive to the output of said pulse counter for computing the speed (V), in accordance with the number (N) of pulses counted by said pulse counter, the interval (T.sub.M), and the distance (S.sub.M) between said edge of said first projection and said edges of said second projection.

### Claim 2 (depends on 1)

Apparatus according to claim 1, wherein said gate circuit comprises a pitch judging circuit including a flip-flop circuit responsive to the output of said proximity switch for changing its own output between two states, to indicate whether or not said edge of said first projection has passed said proximity switch and said edge of said second projection has not passed said proximity switch, and a movement direction judging circuit including a flip-flop circuit responsive to the output of said pitch judging circuit for changing its own output between two states to indicate whether or not said piston rod is in forward movement.