Terry loop ratio control device

In a terry weaving machine of the kind including a first supply beam from which pile warp yarn is dispensed under the control of a negative type pile warp let-off motor, a second supply beam from which ground warp yarn continuously is dispensed, a reciprocally operable reed and a rocking bar past which said pile and ground warp yarns are directed, said rocking bar being intermittently operable for displacement from a first position towards said reed to a second position and then returning from said second position to the first position, the invention comprising:

• means for sensing the tension on said pile warp yarn to produce a first electrical signal;
• means for sensing the rate at which the pile warp yarn is dispensed from the first supply beam to produce a second electrical signal;
• circuit means responsive to:
• said first signal, said second signal, to data representative of the rate at which ground warp yarn is continuously dispensed, and to a pre-programmed desired pile-to-ground warp ratio, to produce first and second output signals, said first output signal being determined by a difference between the desired pile-to-ground warp ratio and an actual pile-to-ground warp ratio calculated by said circuit means from said second electrical signal and said data, and said second output signal occurring when said difference exceeds a threshold level;
• means for connecting the first output signal to said pile warp let-off motor to alter the rate at which the pile warp yarn is dispensed;
• and
• means responsive to said second output signal for altering the distance between the second position of the rocking bar and said reed to thereby alter the height of terry produced when the rocking bar is in the second position.