GB1193914A - Improvements in Devices for Clamping Wood and the Like - Google Patents

Abstract

1,193,914. Sawing. ETABS. GUILLIET. 19 Feb., 1968 [21 Feb., 1967], No. 7959/68. Heading B5L. [Also in Division F2] A device for clamping a log on a log-saw carriage comprises two transmission systems in parallel and having different ratios, the high speed system being preponderant, and a friction coupling coaxial with the screw of the device and controlled by the reaction of the latter to make the low speed system preponderant during the active phase of clamping or unclamping. The carriage has an upright 1 formed with a vertical rectangular guideway for supports 12, 13 having opposing grips 14, 15. A screw 2 is rotatably mounted in the lower support and engages a nut 16 fixed to the upper support. The upper end of the screw is keyed for axial movement in a sleeve 5 rotatable in the carriage 1. A plate 6 is keyed to the sleeve and carries a pulley 21 which is connected to the plate by tangentially disposed springs 28 extending between pins 42 on the pulley and a lug 41 on the plate. A gear 7 is rotatable relative to the plate but can be locked thereto by friction rollers 33 engaging wedge-shaped recesses 34 in the plate. The gear 7 engages an intermediate gear 30 on a shaft 40 having a further gear 29 meshing with a gear 4 keyed to the shaft 9 of an electric motor 3. The pulley 21 is joined by a belt 22 to a pulley 20 held between friction pads 24 on the motor shaft 9. In operation, with a log in position on the carriage, the motor 3 is actuated and, with the springs 28 maintaining the projection 41, and hence the rollers 33 in a mid position so that there is no drive between the plate 6 and gear 7, the belt 22 rotates the screw at the high speed to lower the upper clamp into engagement with the log. The nut 16 is thus fixed and the screw moves upwardly so that the lower clamp engages the log. As the clamps exert force in the log, the load on the screw moves the plate 6 relative to the pulley against the force of the springs 28 until the rollers 33 frictionally engage the recesses 34 on gear 7 and the screw is rotated at the lower speed by the gearing 7, 30, 29 and 4 from the motor shaft 9, the pulley 20 turning against the pressure of the friction pads 24. In other embodiments, the device is of the type having a collar for the pieces of wood and the like or of the centring type in which the screw has two portions threaded in opposite directions, each position carrying a nut provided with a centring plate.