Patent GB-107728-A (GB)
Title: Improvements in or relating to Supporting or Locking Devices for Work Supports or other Movable Elements of Boot or Shoe Machines.
IPC: A43D71/02
Filed: 1916-06-02
Abstract: 107,728. Jerram, A. E., Gouldbourn, J.. and British United Shoe Machinery Co. June 2, 1916. Loose-nailing; work supports.-Relates to supporting or locking devices for movable elements of boot and shoe machines, particularly applicable in connexion with work-measuring devices such as those of sole-levelling machines as of the type described in Specification 6068/07, [Class 17, Boots &c.], of loose nailers and like fastener-inserting machines, of heeling machinery, and in various adjustable or disconnectible devices of boot and shoe machines generally, and consists in providing between an element to be supported against a thrust and wedge supporting-means a block or roll which, when the element is supported by the aforesaid means, is thrust by the element against an abutment and is also thrust across the abutment against the wedge supporting-means. The invention is described in connexion with the jack of a sole-levelling machine. The jack comprises a support 29 for an iron last provided with a cylindrical shank 31 adjustable in a carrier 32, which is pivoted by ears 100 so that, in the operation of the machine, it may be swung in known manner from a vertical work-receiving position to an inclined position in alinement with the presser-applying form. The support 29 is upwardly pressed by two springs 60, 61 to an amount limited by a bolt 58', which passes loosely through a flange 59 on the carrier and adjustably engages a hole in a flange 57<1> on the support. The shank 31 is slotted at 56 and the lower walls 57, 58 of the slot are inclined outwards at equal angles to co-act with inclined faces 64 on wedges 62, 63 mounted to slide towards and from one another upon fixed supports 66. The wedges 62, 63 are also formed with other but differently inclined faces 65 in engagement with a longitudinally-movable wedge 67, which is pivoted on a link 68 connected to the inner end of a lever 69 fulcrummed near its outer end on a rod 70 pivoted to the flange 57<1>. A spring-pressed plunger 71 bears on the outer end of the lever 69 and normally acts to thrust the wedge 67 upwards. The angle of the wedge 67 is somewhat less than twice the angle whose tangent is equal to the coefficient of friction between the surface of the wedge 67 and the surface 65 of one or other of the wedges 62, 63, while the angle between the inclined walls 57, 58 is considerably greater; as a consequence a slight movement of the carrier 31 necessitates a proportionately greater movement of the wedge 67 to prevent the wedges 67, 62, 63 from binding, and for this purpose the fulcrum of the lever 69 is located near its outer end. In the operation of the machine, with the jack in levelling position, a member is moved into engagement with the outer end of the lever 69 to provide a solid abutment for that end of the lever at the time the levelling- form first engages the work; if at this time the support is depressed by the form as a result of any increase in the thickness of the shoe bottom the rod 70 will cause the lever 69 to swing about this abutment and withdraw the wedge 67 sufficiently to prevent it from binding between the wedges 62, 63. As the member above referred to passes from beneath the end of the lever 69 the plunger 71 swings this lever to raise the wedge between the wedges 62, 63 and so to lock the support against the levelling pressure. Specification 107,614, [Class 17 (i), Boots and shoes, Apparatus for making &c.], also is referred to.