US 4,764,875 AGranted

Positive yarn feed

OwnerFrederick H. Carrotte, John R. Stewart +1inventors

InventorsFrederick H. Carrotte, John R. Stewart, Kurt Jacobsson

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Abstract

A positive yarn feed device comprises a pin wheel mechanism (3,4,8,9,10,11) with independent drive means which comprise a variable-speed electric motor (16). The speed of the DC motor (16) is controlled by programmed control means (24,28) which exercise control on the basis of a comparison between an input from speed sensing means (26) associated with the yarn feed device and an input representative of the speed of the cylinder (20) of a circular knitting machine to which the yarn is fed. The comparison of the speed input signals is evaluated against desired speed ratio data stored in a look-up table (31) in programmable memory M. Motor speed control signals output from a microprocessor unit (24) control a variable speed drive unit (28) which directly controls the speed of the motor (16).

Claims14

Dependent claims

A system for applying positive yarn feed to a circular knitting machine, comprising:

a positive yarn feed device for feeding yarn to the circular knitting machine;
a variable-speed electric motor drive for said positive yarn feed device, said motor drive being independent of the drive of said knitting machine;
first speed sensing means for sensing the speed of a knitting cylinder of the circular knitting machine and supplying a first electrical signal representative of the speed of said knitting cylinder;
second speed sensing means for supplying a second electrical signal representative of the speed of said positive yarn feed device;
programmable storage means for storing a preselected speed ratio signal representative of a desired ratio of the speeds of said positive yarn feed device and said knitting cylinder;
and
control means for comparing said first and second signals to produce an actual speed ratio signal, comparing said actual speed ratio signal with said preselected speed ratio signal and controlling the speed of said positive yarn feed device in dependence on said comparison.

4 more elements

Dependencies are inferred from the claim text.