GB1131843A - Retractable safety belts - Google Patents

Abstract

1,131,843. Safety harness. R. G. BOARD and N. H. SHAPIRO. 5 Nov., 1965 [5 Nov., 1964], No. 47033/65. Heading A3V. [Also in Division E2] A retractable safety strap arrangement includes clamping means for preventing extension of the strap which is automatically rendered inoperative in response to retraction of the strap on to a spring reel to a predetermined extent, remains inoperative until a sufficient length has been withdrawn from the reel and, when tension applied to the strap to withdraw it is relaxed, is automatically rendered operative to prevent further extension of the strap. A strap 10 passes from a spring reel 90 in a housing 12 over a guide roller 110, between a fixed clamping block 96 and a pivoting clamping lever 98 which carries a roller 104 located between, and bearing on one opposite face of the strap to, fixed rollers 106, 108. Pull on the strap 10 pivots the lever 98 to clamping position. To hold the lever in open position to allow unwinding of the strap for use, a feeler device is provided including an arm 116, pivoted to the housing 12 at 118 and engaging the strap wound on the reel, and an arm 120 engageable in a notch 122 in the pivoted lever 98. Springs 124 and 114 respectively urge the arm 120 out of engagement with the lever 98 and lever 98 away from the clamping position. With the strap fully wound on the reel the arm 116 engages an abutment 126 on the housing holding the arm 120 in the position shown in Fig. 3 and the lever 98 is located slightly lower than its position in Fig. 3. Pull on the strap pivots the lever causing the arm 120 to engage the notch 122 and prevent the lever from moving to clamping position. By the time a sufficient length of strap has been unwound for use the arm 116 will have lost contact with the reel. Momentary relaxation of tension in the strap then will allow springs 114 and 124 to pivot the lever 98 and arm 120 out of engagement, the lever 98 moving into clamping position, Fig. 4 (not shown), in response to renewed tension in the strap. When the strap is unfastened the spring 114 moves the lever 98 to the open position and the strap retracts. In a second embodiment, Figs. 5-8 (not shown), a clamping device, including a U-shaped bracket and a knurled pin (218) movable towards and away from the base of the U, remains in the open position of Fig. 6 whilst a sufficient length of strap is withdrawn from the reel when relaxation of tension in the starp causes it to flip about its pivots (212), (214) to the clamping position of Fig. 7. To move the clamping bracket to the open position of Fig. 6 before the strap is extended, a spring (228) is associated with pivot (214) which when the strap is unfastened turns the clamp through 100 degrees from Fig. 7 to Fig. 8 position to allow retraction of the strap and a feeler device includes an arm (238) which when the reel has filled is moved to engage a roller on the bracket and turn it to the position of Fig. 6.