Patent GB-805264-A (GB)
Title: Improvements in or relating to rope slings
IPC: B66C1/12
Filed: 1955-01-06
Abstract: 805,264. Slings for handling loads. ARCHER, J. F. Jan. 6, 1955 [Jan. 12, 1954; Feb. 11, 1954; Dec. 7, 1954], No. 382/55. Class 78 (4). A line passing over a saddle member so that its two ends hang down to form two legs of the sling is automatically locked against movement relatively to the saddle either when a load is applied to it or when the two legs are unequally tensioned, and means are provided for limiting rocking movement of the saddle which is engaged by the supporting hook or the equivalent below the part of the support over which the line passes. In the construction of Fig. 14, the line 3 is locked to the saddle 1 simply by being taken a complete turn about the saddle and the hook 2 engages in an eccentric hole 37 in the saddle so that rocking movement of the saddle is limited by the turning movement applied by line 3 whenever the saddle rocks out of the symmetrical position. In an alternative construction the aperture 37 is concentric with the periphery of the saddle rocking movement of which is limited in one or both directions by bolts bridging the flanges forming the groove for the line 3. A bolt may be provided to tighten against part of the line 3 wrapped on the saddle 1 so that the line 3 may be locked against movement relatively to the saddle even when unloaded. In the construction of Fig. 21, each leg 3 of the sling bears on a bridge 56 carried by a member 54 pivoted at 53 to the saddle 51 so that pivotal movement of the member 54 in the direction of the arrows 59 when the sling is loaded causes dogs 58 pivoted at 57 to the members 54 to grip the line. The dogs 58 are so shaped that they also grip the line when the legs of the sling are raised to the position 31 to cause pivotal movement of the dogs 58 in the direction of the arrows 66. A compression spring 61 biases the member 54 to the position in which the line is free and the rocking movement of the saddle 51 is again limited by the restoring forces set up when the saddle moves out of the position of symmetry on the hook 2. The construction of Fig. 13 is similar to that of Fig. 21 except that the dogs 58 are omitted and the ends 31b of the arms 31 serve to grip the line against the upper portion 27 of the saddle. The hook 2 may be held by a screw-adjusted crutch 34 as shown or rocking may be limited by pins projecting from the portion 27 of the saddle to engage the flanks of the hook. In a further construction (Fig. 19, not shown), the arms 31 are pivoted near their lower ends and are moved by tension in the line to press a wedge disposed between their upper ends upwardly to grip the line against the portion 27 of the saddle. In still a further construction (Fig. 11, not shown), all the portions of the arms 31 shown in Fig. 13, below the pivots 30 are omitted and the hook engages directly against the ends 31b of these arms to press them against the line. In some constructions the line is locked to the saddle only when the tensions in the two legs of the sling are unequal. Thus, in the construction of Fig. 5, rocking movement of the saddle 1 on the hook 2 causes one of two rods 16 loosely carried by rectangular sockets 18 at the ends of the bell-cranks 14 to engage the corresponding flank of the hook 2 so pressing the lower arm 17 of the bell-crank against the line 3. In a further construction (Fig. 4, not shown), pins bridging the flanges of the saddle 1 are carried by suitably shaped slots in the flanges so that when the saddle 1 rocks to bring a pin into engagement with a flank of the hook 2 the pin is forced, against the bias of a spring joining the two pins, down the slots to grip the line against the core of the saddle. In a further construction (Fig. 8, not shown), cranks mounted to turn about radial axes on the saddle 1 have each an arm brought into engagement with the hook 2 by rocking movement of the saddle 1 so that the crank is turned to cause a second arm to grip the rope 3 against the core of the saddle 1. In the construction of Fig. 16, unequal tension in the legs 3 of the sling turns the saddle 42 about a pivot 38 relatively to a yoke 40 engaged by the hook 2 and carrying pins 40a which grip the line 3 against the saddle 42. In a similar construction (Fig. 15, not shown), the pivot 38 is above the pins 40a. In the construction of Fig. 17, two plates 39 secured to the saddle 1 converge downwardly so that when the saddle is turned on the hook the line 3 is wedged between more closelyspaced portions of the plates 39. In the construction of Fig. 18, cheeks 44 forming the saddle are caused to grip the line 3 when the tension in the cable deflects links 45 joining the cheeks 44. The links 45 may be replaced by a strip of fabric joining the cheeks 44. The line 3 may be gripped by the convolutions of a spiral spring 69, Fig. 22, through which it passes, when the spring is distorted by the tension in the line. Alternatively the line may be gripped by the rollers of a meandering chain 70, Fig. 23, distorted by engagement with the hook 2 when the sling is loaded.