Coil Clutch and Pulley Co
of Gotha Works, Slough
1897 'It is well known that if a rope be made fast at one end, and be wound three or four times around a rotating shaft, it makes a most effectual brake, provided the shaft be running in the direction to tighten the convolutions. A slight pull applied to the tail of the rope is multiplied several times by each turn, until a very intense pressure is attained. It is on this phenomenon that Lindsay's clutch, manufactured by the Coil Clutch and Pulley Company, of Gotha Works, Slough, is founded. For the rope coil there is substituted, however, a helix of square steel, so arranged that the tail end may be made to grip or release the rotating shaft at will. If one end of such a helix be attached to a pulley, and the other end be made to grasp the shaft, motion can be conveyed from the one to the other by reason of the frictional grip of the helix on the shaft. If the parts be properly proportioned it is possible to throw such a clutch into gear absolutely without shock, sufficient slip taking place to render the start quite easy, while at the same time it is absolutely certain. ...'[1]. The article ilustrated reversing clutches for 2000 HP constructed for one of William Foster and Co.'s rolling mills, where they had been in use for the fifteen months. 'Clutches of this type have been already adopted by several large rolling mills, and a pB;.ir are now in construction for a French firm for their armour-plate mill equal to 10,000 horse- power on a 19-in. steel shaft. So complete is the control exercised by the starting gear that the clutches can be started quite gradually and if desirable permitted to slip, and they can also be stopped and started with the full working load on as easily as when the rolls are empty.'