25,991. Casgrain, L. A. Nov. 22, 1910, [Convention date]. Screwing.-A screwing-machine of the type described in Specification 1492/93, comprising a rotating wire-carrying spindle and a lateral cam shaft which is driven therefrom to actuate the co-operating parts of the machine and is balanced by a second lateral shaft, is provided with clutches on each of the lateral shafts for throwing them out of operation when it is desired to stop the insertion of screws. The clutches are so arranged that the shafts 28, 30 will be disconnected from the spindle 6 at predetermined angles of their rotation, so that a full-length fastener will be fed when the cam shaft is again rendered inoperative. Each clutch comprises a toothed collar 44, clamped upon the hub 46 of one of the worm-wheels 24, 26 driven from the rotating spindle 6, with which a sliding clutch member 50, also provided with teeth, is adapted to engage. The member 50 is provided with internal teeth 56, which engage teeth 58 on the cam shaft. The member 50 is moved along the shaft into engagement with the rotating member bv a spiral spring 66 mounted on the end of the shaft 28 and adapted to turn a casing 62 provided with studs 82 which enter spiral slots 80 in the member 50. The casing 62 is normally held with the springs 66 wound up by lugs 104 on the casing engaging stops 102 on a treadle-actuated lever 90. When the lever is depressed, the stops 102 are lowered and the casing 62 turns, thus throwing in the clutch by the action of the pins in the slots 80. On releasing the lever, the stops engage the lugs 104, locking the casing against rotation, and then unclutching the member 50. Each clutch casing has two lugs 104, so that it may be stopped at either of two angles of rotation of the shaft, since the cams on the shaft 28 are arranged to operate for each half-rotation of the shaft. A spring brake is arranged to stop the shafts 28, 30 when the clutch is released. The wire is fed to the inserting - mechanism through a check comprising two grooved rolls 156, 158, Fig. 7, which are supported by springs so that their axles are normally pressed towards the upper end of converging openings 172 in the sides of the casing of the check, thus pressing the rolls against each other and gripping the wire. The work is supported on a horn 2, which, when the machine is operating to insert fasteners, is maintained in work-clamping position by a spring 106, and which is depressed against this spring to feed the work after each fastener is inserted, by a cam operating through a lever 108, link 118, thickness-compensating mechanism 112, 116, and a rod 120 and toggle 122, 124 on the lever 126 on which the horn rod 132 is supported. The thickness-compensating mechanism is similar to that described in Specification 6971/98, [Class 17, Boots &c.]. The toggle 122, 124 is maintained straight while fasteners are inserted, but is broken when the treadle 86 is released, thus permitting the horn to be lowered for the removal of the work. A link 136 connects an arm extending from the treadle to an extension of the toggle link 124. Specification 8500/98, [Class 17, Boots &c.], is also referred to.