US3575404A - Protective shroud assembly for installation about stressed coil springs - Google Patents

Abstract

A protective assembly for coil springs to protect life and property should the springs fail while stressed. The protective shroud is installable about the spring while under stress without need for unloading the spring or using any except simple tools.

Description

United States Patent Herman Otto Wesch 2265 Brentford Road, San Marino, Calif. 91 108 [2]] Appl. No. 789,211

[22] Filed Jan. 6, 1969 [45] Patented Apr. 20, I971 [72] inventor [54] PROTECTIVE SIIROUD ASSEMBLY FOR INSTALLATION ABOUT STRESSED COIL SPRINGS 5 Claims, 5 Drawing Figs.

[52] U.S.C| 267/74, 267/171 [51] lnt.CI Fl6t' 1/12 [50] Field of Search 267/166, 180,178, 74,171

[56] References Cited I UNITED STATES PATENTS 1,598,480 8/1926 Deal 267/74 2,129,338 9/1938 Timmons 267/74 Primary Examiner.lames B. Marbert Attorney-Sellers and Brace ABSTRACT: A protective assembly for coil springs to protect life and property should the springs fail while stressed. The protective shroud is installable about the spring while under stress without need for unloading the spring or using any except simple tools.

Patented April 20, 1971 3,575,404

INVENTOR f/(ffMA/k/ 0770 W650? PROTECTIVE SHROUD ASSEMBLY FOR INSTALLATION ABOUT STRESSED COIL SPRINGS It is common experience for highly stressed coil springs, as for example, those commonly used to operate counterbalanced overhead doors to fail and release the highly stressed fragments at high velocity hazardous to life and property in the vicinity. Various expedients have been proposed heretofore to safeguard against these hazards, but these have been subject to numerous disadvantages and shortcomings sought to be obviated by the present invention. For example, it has been proposed to use different modes of encasing the springs in a manner to prevent the parts escaping. However, the installation of such devices necessitate disassembly of the spring and associated parts of the counterbalance linkage which, in itself, is hazardous, particularly to inexperienced personnel lacking proper jigs and safeguards. Furthennore, this is a time consuming and a costly operation requiring skill and special tools to effect the disassembly and reassembly safely.

To avoid these and other shortcomings of prior expedients there is provided by this invention a simple set of components readily assembled about an installed spring already under stress. Neither special tools nor experience is required and it is unnecessary for the operator to disassembly any part of the unit. The invention protective assembly consists of two pairs of semicylindrieal members of different diameters readily telcscopable one within the other and fully enclosing the spring, even when fully extended. Assembly pins serve to connect the remote ends of the assembled tubes to the adjacent ends of the spring. Additional protection is afforded by flexible tie means connecting the individual shroud tubes to a fixed anchorage and, desirably, by a pair of telescoping interlooped links extending through the center of the spring to anchor points with the adjacent spring ends and the shroud tubes. Irrespective of the mode or the number of pans resulting from spring failure, all are held positively captive by these several and independently acting safeguards.

Accordingly, it is a primary object of this invention to provide a new and improved protective assembly for installation about a previously installed and stressed spring without need for disconnecting or unloading the spring.

Another object of the invention is the provision of simple, inexpensive, rugged components easily assembled by the novice with simple tools about an already installed spring of a door counterbalance mechanism.

More specifically it is an object of this invention to provide pairs of semicylindrieal shroud parts readily secured together about a loaded coil spring together with means for securing the assembled shroud parts to a fixed anchorage.

These and other more specific objects will appear upon reading the following specification and claims and upon considering in connection therewith the attached drawings to which they relate.

Referring now to the drawings in which preferred embodiments of the invention are illustrated.

FIG. I is a fragmentary elevational view of an overhead door with a typical counterbalance mechanism having the invention protective assembly enclosing the operating spring thereof;

FIG. 2 is a longitudinal cross-sectional view on an enlarged scale through the spring in FIG. 1;

FIGS. 3 and 4 are cross-sectional views taken along lines 3-3 and 4-4 on FIG. 2; and

FIG. 5 is a fragmentary cross-sectional view taken along line 5'5 on FIG. 2.

Referring initially to FIG. 1 there is shown an illustrative counterbalance mechanism, designated generally 10, installed on an overhead door 11 and effective to assist its'movement between closed and opened positions, the latter being indicated by dot-and-dash lines. The counterbalance includes a pair of triangularly disposed brackets secured to the door with outer ends joumaled on a pin 13 suitably fixed to an adjacent portion of the building wall. The lower end of a powerful tension coil spring 15 is secured to bracket 12 by a chain 16 and its upper end is secured to a fixed part of the building, as by an anchor hook 18. The spring is highly stressed when door 11 is in closed position and, acting in concert with a companion counterbalance and spring mechanism not shown but located at the other end of door 11, is effective to support by far the major weight of door 11 while closed. Accordingly, relatively slight upward force is required to initiate clockwise pivotal movement of the door about pivot pin I3.

Owing to the highly stressed condition of spring 15 in the closed position of the door it not infrequently happens that the spring fails suddenly and without warning. This may occur at any time while the door is closed or while approaching closed position. Persons present in the vicinity can suffer serious injury or loss of life from flying parts of the spring. Other serious injury results to the property in the area or to the building itself.

Such occurrences are safeguarded against by this invention comprising two pairs of semicylindrieal sleeves 20, 21 of differing diameters so as to telescope readily and without interference one within the other. As best appears from FIGS. 3 to 5, smaller sleeve 20 comprises semicylindrieal halves 24, 25 each provided with radial flanges 26, 27 and rigidly clamped together by bolts 28. Likewise the larger diameter sleeve 2] comprises semicylindrieal halves 29, 30 with similar radial flanges held together by bolts 31. As herein shown, counterbalance springs 15 are provided with steel mounting straps 35 appropriately notched along their lateral edges for rotation into mating relation with the end convolutions of the spring. The outer ends of straps are formed with elongated notches 36 to accommodate a chain 16 or a hook 18, or other means for holding the spring assembled to the counterbalance mechanism. Accordingly, there is ample excess space at the inner ends of slots 36 to receive a pin or bolt 39 extending through aligned openings at the outer ends of the tubular shrouds 20, 21 in the manner best illustrated in FIG. 5. This bolt is preferably provided with spacer sleeves 40 to assure that the shroud tubes are spaced concentrically of one another and of spring I5.

It is possible that spring l5 may fragment into various parts simultaneously. To avoid any possibility of these fragments escaping, there is preferably provided a pair of innerlooped links 43, 44 (FIG. 2). These endless links are located centrally of the spring and arranged to telescope while interlocked lengthwise of one another. The opposite ends of the links or loops are preferably twisted to provide a mounting loop through which pins 39 extend. Loops 43, 44 are sufficiently long as to permit the spring to be extended to its maximum without placing a load on safety loops 43, 44. Accordingly, these loops perform no function normally but, like shroud tubes 20, 2], remain in readiness to retain broken convolutions of the spring captive should the spring fail.

Additionally it is preferred that each end of the protective shroud tubes 20, 21 be anchored to some permanent structure. For this purpose each shroud tube is provided with a flexible tie such as chains 46, 47 having one end anchored to pins 39 and the other to support bracket 12 or to member 49 of the building structure.

From the foregoing it is readily apparent that the described protective assembly is easily installed about a spring 15. Smaller diameter tube 20 is first assembled against the opposite sides of the lower half of spring 15 and locked in place by assembly bolts 28. A pin or bolt at 39 is also inserted across the lower end of the shroud tube and anchored to the support strap 35 of the spring by passing the bolt through opening 36. As the bolt is inserted through opening 36 it is also passed through spaces 40 and through the loop at the lower end of safety link 44.

Thereafter the upper and larger shroud tube 21 is assembled in the same manner to the upper portion of spring 15. Before tightening the nut on bolt 39, the safety chains 46, 47 are inserted over the end of the bolt. Finally, the free ends of the safety chains 46, 47 are secured to an adjacent permanent part of the assembly thereby completing the installation of the safety protective unit.

While the particular protective shroud assembly for installation about stressed coil springs herein shown and disclosed in detail is fully capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as defined in the appended claims.

lclaim:

1. ln a counterbalanced overhead door assembly of the type utilizing tension coil spring to power a counterbalanced dooroperating linkage assembly, that improvement which comprises a protective assembly designed for assembly about said tension coil spring while in place under load without need for detaching or unloading the spring, said protective assembly including pairs of semicylindrical members of different diameters sized to embrace said spring loosely, means for holding each pair of said members securely together with their adjacent ends loosely telcscoped together, pin means extending diametrically through the remote ends of said pair of members and through means connecting said springs to an adjacent part of said counterbalance assembly.

2. The combination defined in claim I characterized in the provision of flexible high-strength tie means extending axially of said spring and of sufficient length as not to interfere with the extension and contraction of said spring during opening and closing of the door but effective to hold said pairs of cylindrical members and the parts of the spring captive should the spring fail.

3. That method of enshrouding the tension coil spring of previously installed overhead door counterbalance assemblies without need for disconnecting the installed stressed spring and irrespective of the stressed condition of the spring which method comprises: embracing the opposite end halves of an installed spring with pairs of semicylindrical members of sufficiently different diameters to telescope over one another while allowing the spring to expand and contract, securing said pairs of members together, and securing an end of each pair of members to the adjacent end of the spring.

4. That method defined in claim 3 characterized in the step of connecting one end of a high-strength flexible tie member to each pair of cylindrical members and the other end of said tie members to a high-strength anchorage.

5. That method defined in claim 3 characterized in the step of installing a pair of interlooped elongated loops axially of said spring, and connecting the remote ends of said pair of loops to an adjacent respective end of said spring thereby to tie the remote ends of said spring and of said pair of semicylindrical members together and prevent the escape of convolutions of said spring upon multiple failure of said spring.

Claims (5)

1. In a counterbalanced overhead door assembly of the type utilizing tension coil spring to power a counterbalanced dooroperating linkage assembly, that improvement which comprises a protective assembly designed for assembly about said tension coil spring while in place under load without need for detaching or unloading the spring, said protective assembly including pairs of semicylindrical members of different diameters sized to embrace said spring loosely, means for holding each pair of said members securely together with their adjacent ends loosely telescoped together, pin means extending diametrically through the remote ends of said pair of members and through means connecting said springs to an adjacent part of said counterbalance assembly.

2. The combination defined in claim 1 characterized in the provision of flexible high-strength tie means extending axially of said spring and of sufficient length as not to interfere with the extension and contraction of said spring during opening and closing of the door but effective to hold said pairs of cylindrical members and the parts of the spring captive should the spring fail.

3. That method of enshrouding the tension coil spring of previously installed overhead door counterbalance assemblies without need for disconnecting the installed stressed spring and irrespective of the stressed condition of the spring which method comprises: embracing the opposite end halves of an installed spring with pairs of semicylindrical members of sufficiently different diameters to telescope over one another while allowing the spring to expand and contract, securing said pairs of members together, and securing an end of each pair of members to the adjacent end of the spring.

4. That method defined in claim 3 characterized in the step of connecting one end of a high-strength flexible tie member to each pair of cylindrical members and the other end of said tie members to a high-strength anchorage.

5. That method defined in claim 3 characterized in the step of installing a pair of interlooped elongated loops axially of said spring, and connecting the remote ends of said pair of loops to an adjacent respective end of said spring thereby to tie the remote ends of said spring and of said pair of semicylindrical members together and prevent the escape of convolutions of said spring upon multiple failure of said spring.

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