Patent GB-170277-A (GB)
Title: Improvements in hack saw machines
IPC: B23D49/00
Filed: 1921-09-19
Abstract: 170,277. Hassler, S. Sept. 19, 1921. Reciprocating-saw machines.-In an automatic hack-sawing machine the descent of the saw frame controls the clamping and feeding of the work as well as the saw driving mechanism, by the action of a bar 24. The saw being at rest in the raised position, as in Fig. 1, the machine is started by moving the lever 61 to actuate the clutch 68, which connects the main driving pulley 5 to a pinion 32 which gears with a wheel 33 and so drives a shaft 34 carrying a disc 35. The same clutching action also starts the rotation of a worm wheel 15, which, upon the actuation of a second clutch 27, as described below, drives a feed shaft 17. On beginning to rotate, from the position in Fig. 1, the disc 35 raises a rod 37, a nose 40 on which engages a counterweighted catch 42 pivoted to the saw-frame arm 63, which is thereby raised slightly enough to disengage it from the notched lever 45, which is thereupon rocked by the spring 60. The continued rotation of the disc 35 lowers the rod 37, so that the saw descends on to the work when the catch 42 is released. In descending, the arm 63, acting by a slotted link 66, allows the weight on a lever 13 to become effective and clamp the work in place. The descent of the arm 63 also causes a small partial rotation of a disc 51, connected rigidly with the arm by a sleeve 54, which co-operates by means of teeth on its face with a disc 52 loose on the sleeve 54. The two discs are thus pressed apart and the arm 63 together with the shaft 3 is moved against a spring 58 a sufficient distance to engage the shaft 3 with the driving pulley 5, which thereupon operates the saw. By the time the saw has cut through the work, the continued relative rotation of the discs 51, 52 is sufficient to allow them to approach again, thus drawing the shaft 3 out of gear with the pulley and stopping the saw. The disc 35 and rod 37 having released the saw frame continue to move idly until the descent of the arm 63 re-sets the catch 42, the frame being thereby raised again on the completion of the cut. In this re-setting action the rod 37 is pushed down to allow its lower end to catch the end of the bar 24, so that the same rotation of the disc 35 which raises the frame also slides the bar 24 (to the left in Fig. 1), and thereby operates the clutch 27 through a lever 29. This crutches the shaft 17 to the worm wheel 15 and rotates a feed roller 16, thus feeding the work (the raising of the frame having loosened the clamp 12) until it meets an adjustable finger 21 mounted on a cross slide 22, the movement of which trips the bar 24 under the action of a spring 23 and stops the shaft 17. The saw frame is now brought down again by the rod 37 and the above-described operations are repeated, until the rear end of the work is fed clear of the bar 62, when the latter is moved by a spring,. disengaging the clutch 68 and stopping the machine. In a modified arrangement the disc 35 drives the rod 37 through clutch members,. which are engaged and disengaged by a spring- operated cam mounted on the machine frame,. the catch 42 being omitted.