Patent GB-210819-A (GB)
Title: Improvements in and relating to tension regulating devices for ropes, chains, wires and the like
IPC: F16H7/14
Filed: 1922-10-06
Abstract: 210,819. Eccles, W. H. Oct. 6, 1922. Rope 'and chain stress-limiting devices.-For limiting the stress in a rope or cable, the direct pull of the main rope, or of an auxiliary rope connected thereto, is arranged to relieve a brake at the predetermined stress so that the rope can be paid out. Numerous examples are given of the application of the invention, one simple form being shown in Fig. 1, where a predetermined tension of the rope R withdraws the brake block B<1> against the pressure of the spring C and so allows the drum A<1> to pay out the rope. In one modification the main rope R is connected to the hook of a pulley, the latter being mounted in a loop of an auxiliary rope passing from the drum A<1> to the pivoted arm of the brake block. In this case the tension of the rope R is transmitted through the pulley to the loop of rope, and the drum pays out to increase the length of the loop. A band brake may be used instead of the brake block. Fig. 4 shows an example in which a belt B<1> serves both as a brake and as a re-winding means for the rope R. At a predetermined tension, both during use or when winding up by the worm gear D, the rope operates the bent lever B and forces a small pulley away from the belt against the action of a spring. Fig. 6 shows an example in which the pull on the rope moves the drum A<1> in its bearings against the pressure of a spring to relieve the tension in a combined brake and rewinding band B<1>. The movement of the drum may release it from contact with a fixed brake block instead of relieving a band. As a further modification of this form, the drum framing may be hinged so as to move bodily away from a fixed brake block. Fig. 10 shows a construction in which a friction clutch is employed. The pivoted arm L is prevented normally from rotating by a weight M on one side and' a spring on the other, but at the predetermined limit the arm L is carried round by the part A<1>, and the screw E then moves it axially for a sufficient distance to allow the part A<1> to shp. Fig. 11 shows three constructions of brake-block mechanism combined in a single figure. In each case the brakeblock B<1> at the stress limit is moved angularly by the drum against the action of a spring or springs, the angular movement also moving the blocks radially away from the periphery of the drum. In this case the disc H is rotated' for rewinding, the blocks B<1> dragging the drum A by friction until slipping occurs. Several other constructions are described in which the tension of the load is balanced normally by a hanging weight. Thus Fig. 12 illustrates one construction in which a brake shoe similar to that shown in Fig. 11 is applied to the drum A<1>, and the normal pull in the rope R is balanced by the hanging weight M attached to the brake-carrying disc. When the excessive tension, by which the brake block is relieved, no longer exists, the weight causes the disc to slip backwards to re-apply the brakes. As a result of this action the weight M gradually falls and may be re-wound in various ways, for example by being formed as a winch to climb the rope. In another construction the end of the rope is secured to a sliding bar instead of being wound on a drum, the brakes being applied to and released from the surface of the bar.