Patent GB-229488-A (GB)
Title: Improvements in machines for cramping timber
IPC: B27M3/00
Filed: 1924-02-19
Abstract: 229,488. Hallworth, H. Feb. 19, 1924. Cramps. - A device for cramping rectangular wood frames &c. consists of a number of jawcarrying carriages, one of which is fixed and the others of which are adjustable with regard to it in the same direction, one or more of the carriages having jaws which operate at right-angles to the jaws carried by the remaining carriages. Two parallel metal tracks 1, Figs. 1 and 3, carry at one end vertical frames 2 supporting a narrow table 3 carrying jaws 4, the parts 2, 3 forming the fixed jaw-carrying carriage. The jaws 4 are mounted in shoes 5, Figs. 12 and 13, which are slidable along the table 3 by means of interengaging dovetail grooves and projections, and carry worm-wheels 17 screwed to engage threaded spindles 18, attached to the jaws 4, by means of which the jaws are adjusted. A shaft 12, journaled in the frames 2, has slidably mounted on it worm 15 fitting between lugs 16 on the shoes 5 and engaging with the worm-wheels 17, the shaft being rotated by a handle 66 through gearing 11, Fig. 1, which can be adjusted by means of a clutch 13, operated by a lever 14, so as to give a quicker or slower movement of the jaws 4. A carriage, carrying jaws 8 opposed to the jaws 4, consists of two vertical frames 6, Fig. 4, slidable along the tracks 1, and a narrow table 7, the jaws 8 being non-adjustable but slidable along the table in a similar manner to the shoes 5, and held in any desired position by a nut 10, Fig. 3, engaging a bolt having its head engaged in a groove in the table. The carriage is moved along the tracks 1 by a handle 54, Figs. 1 and 4, on a shaft 55 journaled in the side frames 6, gear wheels 56 on the shaft meshing with gear wheels 57 carried by the frame and engaging racks on the tracks 1. The wheels 56, 57 are locked in any desired position by a pawl 59. Other carriages carrying jaws 34, 37, Figs. 5 and 23, operating at right-angles to the jaws 4, 8, each consists of vertical members 21 and a cross member 24, the carriage being movable along the tracks by a similar arrangement 61, 62 to that provided for the carriage 6, 7 except that a locking pawl is unnecessary. The jaw 34 is slidably adjustable along a support 35 on the member 24, by means of toggle links 32, 33 attached to a nut 31 on a vertical screwed spindle 30 rotated from a handwheel 25 through chain or other gearing 26 and bevel wheels 28, 29. Two hinge pins 36 support the upper portion of the part 35, and the removal of one of them allows the jaw 34 to be swung into inoperative position below the level of the tables 7, 3 when not required. The opposite jaw 37 is slidable along the member 24 but can be fictionally locked on the member by a bar 38, pivoted to the jaw 37 by links 39, 40, and forced into frictional engagement with the member 24 by a weighted extension 41 of the link 40. To position a wood frame in the cramp so that its sides are perpendicular to the jaws which are to engage them, two pairs of jaws 50, 42, Figs. 1 and 3, are provided. The jaws 50, of angular form, are carried by arms 51 adjustably held by bolts 53 in slides 52 movable along the tables 3, 7. The opposite jaws 42, also of angular shape, are each carried by two links 43, 45 fulerumed on a spindle 48 and bracket 46 respectively, slidable in supports 49 on one. of tables 3, 7. Each link 43 has a weighted extension 44, so that when a frame is placed between the jaws 42, 50, the jaws 42 move against the action of the weighted extensions 44 under the weight of the frame and position the frame at right-angles to the jaws. The jaws 4, 8 have each two limbs so as to embrace any projecting parts of a frame, and the jaws 34, 37 may be similarly formed if required.