Patent GB-538491-A (GB)
Title: Improvements in or relating to safety devices or mechanisms for machinery
IPC: F16P3/00
Filed: 1940-02-03
Abstract: 538,491. Machinery guards. TURNER MACHINERY CO., Ltd., and SCHETTLER, G. A. Feb. 3, 1940, No. 2156. [Classes 80 (ii) and 80 (iv)] A safety device for a machine furnished with a one cycle or a half cycle stop motion, comprises a movable guard and, associated therewith means adapted, when the guard is displaced by a hand &c. contacting therewith both to effect disengagement of the operating machanism independently of the stop motion, i.e. without disturbance and operation of the stop lever, and to apply a brake to the moving parts. As applied to a leather boarding and softening machine a work table has a steel plate 5 over which the skins are laid the table being reciprocated to and from the rollers 1, 2 by a connecting-rod 7 attached to a crank on the driving shaft 9 driven through a friction clutch 12 operable at the will of the operator through a treadle. Engagement and disengagement of the clutch is effected by a lever 16 with a fork 16a connected to a cone 17 by a yoke 18. The cone is connected to the clutch by a toggle 19 and link 20. To control the clutch parts a stop lever 21 has a projection 21a which contacts with the edge of a circular part 22 on the clutch housing 23. The part 22 is peripherally notched at diametrically opposite points to receive the projection 21a and automatically stop the shaft 9 at each half revolution. The lever 16 is controlled by a spring 24 and is connected to the treadle mechanism by a link 25. The levers 16, 21 are releasably connected together by links 26, 27 whereby if the operator's hand contacts with a guard 28, Fig. 1, the lever 16 is disconnected from stop lever 21 to permit of disengagement of the clutch and consequent stoppage of the machine without in any way disturbing the stop lever. The lever 26 is pivotally connected to an arm 16b of lever 16 and has on its underside a notch 26a to receive a pin 29 on a lever 30 pivoted to a bracket 31 on a side frame 4. The link 27 is pivoted to an arm 21b, Fig. 1, of stop lever 21 and is also engaged at or near its other end with pin 29. Assuming the machine to be running, if link 26 be raised, the lever 16 will be turned by spring 24 to disengage the clutch. When both links are engaged by pin 29 they move together. The guard 28 is keyed to a shaft 34 and when moved inwardly by an operator's hand disconnects link 26 from stop lever 21. To effect this, the guard shaft rigidly carries a catch lever 36 normally engaging an element 37a, under the influence of a spring 38. The lever 37 is pivoted at 39 and is connected by a link 40 to a bellcrank 41, the arm 41b of which extends under the link 26. To re-set the mechanism after an emergency stoppage, the trip lever carries a handle 42 by pulling which the catch lever is re-engaged with 37a with the assistance of a spring 43. An arm 16c of the lever 16 carries a link, toggle or like device 44 adapted when the lever 16 turns to disengage the clutch to apply a brake band 45 to a drum 46 on the clutch housing 23 through which the drive is effected. One end of the band is connected to a yieldable member 47 slidable in a fixed guide 49.