Thread supply device for textile machine having common thread control and tension sensing element

Claim 1

In a thread supply device for a textile machine, in particular a knitting machine, said thread supply device including drum means upon which a thread can be tangentially wound to form an intermediate thread storage and from which the thread can be unwound axially over a withdrawal rim associated with the drum means, a stationary thread guide member disposed in axially spaced relationship from the withdrawal rim for guiding the thread withdrawn from said drum means after it passes over the withdrawal rim, thread engagement means positioned for engagement with the withdrawn thread as it extends from said withdrawal rim to said thread guide member for (1) limiting the maximum rate at which the thread can be withdrawn from the drum means and (2) sensing the tension in the withdrawn thread, and switching means interconnected to said thread engaging means and actuated in response to the sensing of a decrease in the withdrawn thread tension below a predetermined value, comprising the improvement wherein said thread engaging means includes a single thread engaging element positioned adjacent the withdrawal rim and normally disposed in engagement with the withdrawn thread after it passes over the withdrawal rim, frame means supporting both said drum means and said thread engaging element for permitting one of said drum means and thread engaging element to be rotated relative to the other substantially about the longitudinal axis of said drum means, said thread engaging element also being supported for movement between first and second positions independently of said above-mentioned relative rotation, said thread engaging element being normally maintained in said second position when the tension in the withdrawn thread equals or is greater than said predetermined value for limiting the withdrawal rate of thread from said drum means, and means for normally urging the thread engaging element away from said second position toward said first position, whereby a decrease in the thread withdrawal tension permits the thread engaging element to move toward the first position and into said first position when the thread withdrawal tension falls below said predetermined value.