Patent GB-134967-A (GB)
IPC: B65H59/24
Abstract: 134,967. Firman, W. G. Nov. 22, 1918. Ordnance.-In a method of equalizing the tension in a wire during coiling on gunbarrel tubes or the like, a force causing two dies to grip the wire, and a transverse force acting to produce deflexion of the wire between two fixed supporting-elements, are combined so that, when the deflexion tends to become greater, the pressure between the dies is increased, and when the deflexion tends to decrease, the pressure decreases. Means are provided to remove inequalities of thickness or local excrescences on the wire. The wire passes from a drum A, through a naphtha bath B containing cleaning-pads, through dies E, F which apply the tension, over rollers between which the tensioning and deflecting loads are applied, and thence to the tube. The wire is deflected the desired amount by a roller L<1>, Fig. 3, carried in a shackle D<1>, which is provided with a spindle E<1> having adjusting-nuts at the end, between which and the bed of the machine is mounted a co led spring G<1>, an indicator U<3> and scale being also provided. The shackle is pressed into contact with a roller carried by a distance-piece in the form of a bell-crank lever pivoted to the guide-block F<1> and having a weighted arm P<2>. The ever P, through which the pressure is communicated to the dies to restore the tension, is pivoted at Q and has a bifurcated hook-shaped end to receive a cross-piece T, which is secured to the rod V of a spring-controlled member X by nuts W iso as to vary the tensioning-load. The springs Z are carried by rods Y secured to the member X and engage between a stirrup A' fixed tc the bed and the heads B<1> of the rods Y, an indicator and scale U<2> showing the tension applied. The deflecting and tensioning loads may be proluced by weights or other means. The coiling is then started to put the tension on the wire until the adjustment is such that the roller L<1> floats and the distancepiece falls out, whereupon the shackle D<1> is secured to a pin K<1> projecting from the member X, by nuts C' screwed on to a split sleeve H<1> projecting from the shackle. Each indicator may co-operate with a movable scale which is set when the desired deflexion has been arranged, so as to indicate when coiling is not being efficiently carried out. A lever D<3>, pivotally attached to a bracket D<4> depending fron the stirrup A' and pivotally connected to the shackle, may work over a scale D<6> on or adjustably attached to the stirrup, instead of, or in addition to, the movable scales. Variation in tension alters the position of the roller and thus throws part of the deflecting-load on to the end of the lever P. This lever acts on a compression member Q<1>, N<1> and increases the pressure on the dies, and so restores the tension. The compression member consists of two elements Q<1>, N<1> guided in the framing and connected by double toggle-levers U<1>, rollers X<1> on the grooved cross-members of which engage inclined cam-edges of slots X<2> in links Y<2>, so that increased pressure is applied to the dies while maintaining the lever P in a substantially constant position. Springs Z<1> on rods Y<1> projecting from the links serve to balance the outward thrust of the toggles. The element N<1> engages a recess in the upper die-carrier or in a removable, piece attached thereto, according to the thickness of wire being operated on. Levers A<2>, adjustably fulcrumed at B<2>, are connected to the lower ends of the links Y<2>, and also by links C<2> to the front end of the upper die-carrier, so that when tension is reduced bv the wear of the dies or alteration in the thickness of wire, the links Y<2> are automatically raised and, through the toggles, increase the pressure on the dies. To compensate for differences of more than about 0.003 inch, adjustment for wear is effected by a wedge K engaging the lower die block. The wedge carries a screw D<2> engaging a nut F<2> secured to a ratchet-wheel G<2> which is operated by an arm H<2> secured to the plunger J<2> of an electro-magnet Q<2>. Wear of the dies operates through levers and links C<2>, A2, L<5>, L<2>, L<3> and a switch K<2>, and the electro-magnet is thus energized, when the toggle adjustment has reached its extreme limit, to raise the plunger and rotate the ratchet-wheel. On the initial movement of the arm H<2>, a second switch in parallel with the switch K<2> is put by in a one-way striker carried or operated by the arm, so as to maintain current in the circuit, when the first contact is broken by movement of the wedge, until the plunger reaches the limit of its stroke, whereupon it is disengaged by a second striker. Each operation of the ratchet moves the dies an amount equal to the extreme adjustment possible in the compression member. When the wedge reaches the limit of its travel, showing that the dies are wom out, it makes contact for ringing a bell, showing a light &c. As shown, the screw D' presses the parts R<2>, S<2> into contact. The dies, which are of the same width as the wire so as to pievent the formation of abutting portions as the dies wear and thus ensure an effective grip on the wire, are carried in grooves in the die blocks, abutments A<3>, B<3> in which support the dies against the tensioning-force. The dies may be removed without dismantling the carrier blocks, by screwed members insert in threaded holes Z<2> in the dies. The lower die has a liquid-circulating system L. On lowering the upper die-carrier until stops V<2> engage the top of the guides M, and lowering the lower die-carrier, the wire may be threaded through the dies without removing the top diecarrier. In order to remove inequalities of thickness or local excrescences on the wire, the wire is wound on the drum A with the perfect side towards the bed of the machine, and is run over a table under a milling-cutter before entering the dies. According to the Provisional Specification, the lever A<2> is connected to the upper die block by a link of adjustable length.