| 摘要 |
1. Lifting hook with safety device, including a hook casing (1) the open buckle of which delimits an inside hooking space (E) and an end of which forms a yoke (1a) for the linking of a closing catch (2) designed for co-operating with the fastening organ of a lifting apparatus or of a hanging organ, the catch (2) supporting in a hinged manner a safety lever (4) elastically and pivotally urged, housed and retracted within the yoke (1a) of the hook casing in the closing position of the catch, the interlocking end (4g) of the lever co-operating with a stop in the hook casing, said lifting hook being characterized in that the interlocking end (4g) of the swivelling safety lever (4) is shaped for abutment against the stop (1e or 8) of the casing, formed on a side of the hooking inside space (E) and adjacent to this space as much as possible, the interlocking lever (4) being of the type in which the fulcrum or pivotal axis (5), placed on a projection (2e) of the catch, is located between the resisting force applied on to the interlocking end (4g) and the motive force applied by finger thrust onto the opposed end (4b) of the lever, externally to the hook casing, the elastic means (6, 7 or 9) having the purpose to bring back permanently the interlocking end of the lever in the locking position against the stop of the casing ; the contacting point of the interlocking end (4g) with the stop (1e) or (8) of the casing being situated at a distance (x) slightly ahead (on the side of the general axis) of the vertical axis passing through the pivotal axis (5) of the vertical while there is provided a comparatively large interval (y) between the linking pin (3) of the catch and the said contacting point, the relative disposition of the three aforesaid points, namely : the pivotal axis (5) of the lever, the linking pin (3) of the catch and the contacting point of the interlocking end (4g) with the stop (1e or 8) permitting to ensure the locking of the catch on the casing of the hook, even when an excessive stress is exerted from the inside space of the catch, while said catch can be released and opened by a voluntary pressure of the finger, without excessive stress on the lever which is free to escape from the stop of the casing. |
