Self-retracting extension limiting device
View Patent ↗A self-retracting extension limiting device. It is designed to be attached between a first object and a second object, where the distance between the first and second objects is variable. The device exerts a restoring force tending to draw the two objects together. A first, relatively weak restoring force is exerted over a range of distance. Then, when the objects have been separated to a defined limit of travel, the device exerts a much greater restoring force. The invention includes overlapping and self-contained elements so that unwanted slack is minimized.
1. A self-retracting extension limiting device, comprising:
a. a first block;
b. a second block;
c. a first connective element lying between said first and second blocks;
d. a second connective element lying between said first block and said first connective element;
e. a first cable connecting said first block to said first connective element;
f. a second cable connecting said second block to said second connective element;
g. a first elastic tensile member connecting said first block to said second connective element; and
h. a second elastic tensile member connecting said second block to said first connective element.
2. A self-retracting extension limiting device as recited in claim 1 , wherein:
a. said first connective element is a first apex block; and
b. said second connective element is a second apex block.
3. A self-retracting extension limiting device as recited in claim 1 , wherein:
a. said first elastic tensile member is a first tension spring; and
b. said second elastic tensile member is a second tension spring.
4. A self-retracting extension limiting device as recited in claim 2 , wherein:
a. said first elastic tensile member is a first tension spring; and
b. said second elastic tensile member is a second tension spring.
5. A self-retracting extension limiting device as recited in claim 2 , wherein:
a. said first apex block includes a first cable guide bore;
b. said second apex block includes a second cable guide bore;
c. said first cable passes through said second cable guide bore in said second apex block; and
d. said second cable passes through said first cable guide bore in said first apex block.
6. A self-retracting extension limiting device as recited in claim 2 , further comprising:
a. a third cable connecting said first block to said first apex block;
b. a fourth cable connecting said second block to said second apex block;
c. wherein said first elastic tensile member is parallel to said first and third cables and lies therebetween; and
d. wherein said second elastic tensile member is parallel to said second and fourth cables and lies therebetween.
7. A self-retracting extension limiting device as recited in claim 6 , wherein:
a. said first apex block includes a first cable guide bore and a second cable guide bore;
b. said second apex block includes a third cable guide bore and a fourth cable guide bore;
c. said first cable passes through said third cable guide bore;
d. said third cable passes through said fourth cable guide bore;
e. said second cable passes through said first cable guide bore; and
f. said fourth cable passes through said second cable guide bore.
8. A self-retracting extension limiting device as recited in claim 7 , wherein:
a. said third cable guide bore is a sliding fit on said first cable;
b. said fourth cable guide bore is a sliding fit on said third cable;
c. said first cable guide bore is a sliding fit on said second cable; and
d. said second cable guide bore is a sliding fit on said fourth cable.
9. A self-retracting extension limiting device as recited in claim 5 , wherein:
a. said first elastic tensile member is a first tension spring; and
b. said second elastic tensile member is a second tension spring.
10. A self-retracting extension limiting device as recited in claim 6 , wherein:
a. said first elastic tensile member is a first tension spring; and
b. said second elastic tensile member is a second tension spring.
11. A self-retracting extension limiting device as recited in claim 7 , wherein:
a. said first elastic tensile member is a first tension spring; and
b. said second elastic tensile member is a second tension spring.
12. A self-retracting extension limiting device as recited in claim 8 , wherein:
a. said first elastic tensile member is a first tension spring; and
b. said second elastic tensile member is a second tension spring.