Safety Devices for Overhead Garage Door Springs

This invention relates to safety devices for overhead garage door springs and particularly to cable safety devices for overhead garage door springs.

Overhead garage doors are generally provided with counterbalance springs which are used to assist in the lifting and opening of the doors. These springs must be relatively powerful and when stretched, as with the doors closed, are under a great tension. These springs, after considerable use, are subject to failure for one or more of a variety of reasons including crystallization, fatigue and other reasons. When this happens under tension, broken pieces of the spring thrash around with great force and frequently serious damage automobiles and other objects within the garage as well as to the building itself.

It is possible to reduce the likelihood of such tension breakage by various means such as longer or heavier springs. Such means as are available are expensive and are an appreciable cost problem and therefore are not an economical solution. The problem has long been recognized and various solutions have been proposed. Among the proposed solutions are those set out in U.S. Pat. No. 3,958,367 and 4,082,133. U.S. Pat. No. 3,958,367, a cable is passed through the spring and fixed at one end to an end bracket and at the other end held by a spring. Such a device is not sufficiently taut to hold a spring which is under great tension and if the door spring breaks it can still thrash around sufficiently to do damage to vehicles in the garage. U.S. Pat. No. 4,082,133 uses a solid rod extending through the spring. The rod is fixed at one end to the door frame and the other end protrudes through a hole in the spring bracket and is bent loosely around the bracket. Here again the rod is free to flex because of the loose end and like that of U.S. Pat. No. 3,958,367 will permit sufficient movement to cause damage to a vehicle in the garage in the case of a break in the door spring.

I have discovered that all of these problems can be solved by using a cable passed axially through the door spring and held under tension against flexure.

I provide a garage or like door structure having a door opening, a door movable between a closed position and an open position, guide tracks against opposite sides of the door opening and having a vertical section parallel to the door opening sides and a horizontal section, rollers on the sides of the door moving in said guide tracks to carry the door from a vertical closure position in the door opening to a horizontal open position above the level of the door opening top, a counterbalance spring assembly for said door including a coil spring mounted for movement in tension parallel to and adjacent said horizontal overhead section, anchor means in the garage structure adjacent the horizontal section of the guide tracks and spaced from the door opening, attaching means at each end of the counterbalance spring assembly, one attachment means at one end engaging said anchor means, a fixed pulley on the garage structure above the door opening and in general alignment with the anchor means on a line generally parallel to the horizontal section of the guide rails, a movable pulley assembly connected to the attachment means at the opposite end of the counterbalance spring assembly, cable means connecting said movable pulley assembly to the garage door over the fixed pulley, a safety cable fixed at one end to the anchor means in the garage structure, an adjustable anchor means in the garage structure adjacent the fixed pulley and aligned with the fixed pulley and anchor means, said safety cable extending through the coil spring of the spring assembly and attached at its other end to the adjustable anchor means, said adjustable anchor means being adjustable to place the cable under sufficient tension that a broken coil spring will be retained or said safety cable against substantial movement relative to the horizontal section of the guide rails. Preferably the fixed pulley is attached to the garage structure above the door opening and has guide means for the safety cable and adjustable anchor means. The movable pulley assembly also preferably carries guide means for the safety cable.

In the foregoing general description I have set out certain objects, purposes and advantages of this invention. Other objects, purposes and advantages of this invention will be apparent from a consideration of the following description and the accompanying drawings in which:

FIG. 1 is an isometric view of an overhead garage door incorporating the safety device of this invention;

FIG. 2 is an enlarged fragmentary side elevational view of the horizontal track and safety device of this invention;

FIG. 3 is an enlarged fragmentary side elevational view of the adjustable anchor end of the safety device of this invention;

FIG. 4 is an enlarged fragmentary top plan view of the adjustable anchor end as shown in FIG. 3;

FIG. 5 is an enlarged fragmentary side elevation viewing a second embodiment of spring and anchor means opposite the adjustable anchor means; and

FIG. 6 is an enlarged fragmentary side elevational view of a third embodiment of anchor means remote from the adjustable anchor means.

Referring to the drawings I have illustrated a garage structure 10 having an opening 11 closed by a door 12 made up of a plurality of side by side hinged horizontal sections. The door 12 has opposite side edges 13 and top and bottom edges 14 and 15. The door has a plurality of rollers 16 on the side edges 13 of each section received in and movable along guide rails or tracks 17. The guide rails are held to side jambs 18 of the door opening by brackets 19. Each guide rail has a vertical portion and a horizontal portion 17a which lies in a plane above the top of the door opening and held by brackets 20 and 21 suspended from ceiling or roof members of the garage. Brackets 21 at the end of each horizontal rail 17a are provided with U-bolts 22 which act as anchor means for one end of counterbalance springs 23. The opposite ends of springs 23 are each connected to a yoke 24 carrying a pulley 25. A fixed pulley 26 is mounted in a yoke 27 attached to the garage structure above the door opening. A cable 28 at each side of the door has one end attached to the adjacent bottom edge 15 and passes over fixed pulley 26, around pulley 25 and back to yoke 27 where it is dead ended. A safety cable 30 is attached at one end to each of U-bolts 22 or to the end of the spring at U-bolt 22 as in FIG. 2 and passed through the center of each of the counterbalance springs 23, through an opening 24a and 27a in each of yoke 24 and yoke 27 and the other end attached to adjustable anchor eye bolt 31 at yoke 27 by a clamp which may be a crimp clamp as shown or a U-bolt cable clamp or any other known cable clamp means. The eye bolt 31 is tightened until cable 30 is under tension sufficient to contain each of springs 23 against substantial vertical or horizontal movement in the event of breakage of either spring.

In FIG. 5, I have illustrated an embodiment in which cable 30' is attached to the hook end 23a of spring 23' which engages the anchor bolt 22' so as to be an integral part of the counterbalance spring 23'.

In FIG. 6, I have illustrated another embodiment of end bracket 21" for attaching and supporting horizontal guide rail 17a" and a notched anchor member 40 to which one end of counterbalance springs 23" can be attached along with one end of safety cable 30". In this embodiment the adjustable anchor would be the same.

The adjustable anchor would be arranged so that it is placed in support bracket 21 rather than at fixed pulley yoke 27 if desired. For example, the U-bolts 22 could have extended threaded leg portions 22a to provide adjustment. This could be the only adjustment or it could be combined with the adjustable eye bolt 31 to provide adjustment at each end of safety cable 30.

In the foregoing specification I have set out certain preferred practices and embodiments of this invention, however it will be understood that this invention may be otherwise embodied within the scope of the following claims.