ends is rotatably mounted in bearing means 248 and 250 one end of the screw member 246 is provided with a sprocket gear 252 which receives rotary power by a chain 254 which is connected to the sprocket gear 100 located on the end 98 of shaft 34 fig2 a housing 256 is mounted on screw 246 and contains ball bearings which are in engagement with the threads of screw member 246 thus rotation of the screw member 246 will effect linear translation of the housing 256 the housing 256 is securely attached as by an arm 258 to the slide beam 240 with the apparatus 10 of the present invention and the carpet tufting machine 218 fig5 arranged as described above it will be seen that when coupling means 80 fig2 is held in its coupled position by latch 98 which is operated by its solenoid 208 the intermittent rotation of shaft 34 will effect intermittent rotation of the screw member 246 thus causing intermittent shifting of the slide beam 240 which is directly transmitted to needle arm 222 when solenoid 208 is deactivated and the solenoid for latch 200 activated coupling means 82 will be retained in its.