US2786231A

US2786231A - Spring adjuster for overhead doors

Info

Publication number: US2786231A
Application number: US460539A
Authority: US
Inventors: Robinson David Malcolm
Original assignee: Stanley Works
Current assignee: Stanley Works
Priority date: 1954-10-06
Filing date: 1954-10-06
Publication date: 1957-03-26
Anticipated expiration: 1974-03-26

Description

March 26, 1957 RQBINSQN' 2,786,231

SPRING ADJUSTER FOR OVERHEAD DOORS Filed Oct. 6, 195.4 2 Sheets-Sheet 1 DAV/D M ROBINSON MM W ATTORNEYS Sign- March 26, 1957 Filed Oct. 6, 1954 D. M. ROBINSON SPRING ADJUSTER FOR OVERHEAD DOORS 2 Sheets-Sheet 2 DA V/D INVENTOR M ROB/IVSON TTORNEYS o -a a SPRING ADJUSTER FOR OVERHEAD DOORS David Malcolm Robinson, New Britain, Conn, assignor to The Stanley Works, New Britain, Conn a corporation of Connecticut Appiication October 6, 1954, Serial No. 460,539

Claims. (Cl. 16-197} This invention relates to improvements in overhead or roll-up doors of the type having torsion counterbalance springs, and more particularly to an improved spring adjusting arrangement for varying the rate of such counterbalance springs.

One object of the invention is to provide a counterbalance arrangement for overhead doors having an improved adaptability to doors of different weights and different displacements between open and closed position.

Another object is to provide in an overhead door a simplified and effective arrangement for enabling the rate of a counterbalance spring to be conveniently adjusted over a wide range, thereby enabling a single size of spring to be used effectively in doors of various weights and sizes.

Another object is to provide in an overhead door an adjustable counterbalance spring arrangement whichis rugged in construction, economical to manufacture, readily adapted to installation in doors now available, and capable of operating effectively for long periods without attention.

Other objects will be in part obvious, and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application of which will be indicated in the appended claims.

In the drawings:

Figure 1 is a fragmentary side elevational view of an overhead door assembly incorporating an adjustable counterbalance spring constructed in accordance with the present invention;

Figure 2 is a fragmentary view of a portion of the structure shown in Figure 1, taken on line 2-2 thereof and partly broken away to show certain structural details;

Figure 3 is an enlarged detail partly sectionalized view of a spring adjuster constructed in accordance with the invention;

Figure 4 is an enlarged end view of the structure of Figure 3; and

Figure 5 is a perspective view of certain of the elements of the structure of Figure 3.

Referring to the drawings, the numeral designates a portion of the frame of a doorway fitted with an overhead door. The numeral 12 designates the door, which is articulate and includes a number of hingedly connected sections 14. The overhead door mechanism includes a frame consisting at each side of the doorway of a horizontal member 16 and a vertical member 18 which in the embodiment shown are angle irons. Supported from the frame at opposite sides of the doorway are the usual tracks 20 within which the door is guided by rollers 22, when moving between its open and closed positions.

Secured to the horizontal frame members 16 at opposite sides of the frame are supports or bearing plates 28, mounting ball bearings 32 within which are journaled ited States the opposite ends of a drive shaft 34. On each end of the drive shaft is pinned a sheave or drum 36 on which is wound a flexible strap 38 connected at its free end 40 to the bottom of the door.

The door is counterbalanced by a torsion spring 42 surrounding the shaft 34 and arranged to rotate the shaft in the proper direction to wind up the straps 38 on the sheaves 36 and thus exert an upward force on the door. The spring is relatively long and heavy, preferably of the type having abutting convolutions, and is somewhat larger in inside diameter when unstressed than shaft 34, as best shown in Figure 3. One end of the spring is maintained stationary relative to the adjacent support 30 and the other end is connected to the shaft 34 at an intermediate point thereon. While the spring may be anchored relative to the support 30 in any desired manner, the arrangement shown in the drawing is preferred. This arrangement is shown in detail in Patent No. 2,630,- 597 and includes a spider 5t) rotatably mounted on the support 35 in coaxial relation with the shaft 34. The spider 50 includes angularly spaced axially extending ears 52 and a central body to which is secured an axially extending tapered anchor tube 54 concentric with the shaft 34. The end of the anchor tube 54 adjacent the spider 50 is larger in diameter than the inside diameter of the spring 52 in its unstressed condition, while the opposite end of the anchor tube is smaller in diameter than the spring and extends into wedging relation with the spring as best shown in Figure 2. One end of the spring 42 is thus carried by the anchor tube 54 and frictionally engages the tube in the manner of a spring clutch to prevent relative rotation between the anchor tube and spring when the spring is loaded in a direction such as to wind it up. For the purpose of enabling the spring to be wound up so as to exert any desired degree of counterbalancing force on the door, the earsof the spider are apertured at 56 to permit the insertion of a bar or lever to enable the spider to be rotated relative to the support 30. When the spring is thus sufficiently wound, the spider may be locked or fixed against rotation relative to the support 30 by any convenient means such as a pin, dog or the like, not shown.

in accordance with the invention, the shaft carries a radially projecting pin 58 which is engaged by a hook 68 on the other end of the spring to support the spring against axial movement and provide a driving connection between the shaft and the spring. The shaft also carries a cylindrical sleeve 62, which has an outside diameter substantially equal to the inside diameter of the spring 42, and is adapted to be inserted concen trically between the shaft and the end portion of the spring 42 adjacent the pin 58. The sleeve has an axially extending slot 64 through which the pin 58 extends so as to provide a driving connection between shaft 34 and the sleeve while permitting the sleeve to be axially adjusted along the shaft. The sleeve is formed of relatively thin stock and has a plurality of longitudinal grooves forming inwardly extending ribs 66 which enhance the rigidity and increase the effective thickness of the sleeve. The ribs 66 ride on the shaft and hold the sleeve in concentric relation therewith while enabling the sleeve to be axially adjusted with reduced friction; A tie plate 68 welded across the slot 64 at one end of the sleeve further increases its rigidity and is threaded to serve as a nut for a setscrew 70 by which the sleeve may be secured on the shaft in any selected axial position.

With this arrangement, since the effective thickness of the sleeve 62 is such as to substantially fill the space between the spring 42 and the shaft 34, insertion of the sleeve in the spring renders inactive each succeeding coil of the spring penetrated by the sleeve. Thus the number of active coils of the spring and hence the effective length and rate of the spring can be readily adjusted simply by axially adjusting the sleeve. To make the adjustment, the spider 50 is first unlocked from the support 30 and the spring 42 unwound. The setscrew 7%) is then loosened and the sleeve slid along the shaft until inserted in the spring to the desired extent. Engagement of hook 60 with pin 58 prevents axial movement of the spring during adjustment of the sleeve. Setscrew '70 is then tightened, the spring is wound up again by rotation of spider 50, and the spider is locked to support 30 to prevent the spring from unwinding. Winding up of the spring wraps the coils of the spring penetrated by sleeve 62 tightly around the sleeve, thus rendering those coils inactive as well as providing a good frictional driving connection between the spring and sleeve.

Thus the effective length and rate of the torsion spring may be readily adjusted to any desired value simply by inserting the sleeve 62 any selected amount within the end of the spring. Since the rate of a spring, of course, is a measure of the force it exerts per unit of displacement, by varying its rate a particular spring can be adjusted to supply the desired amount of counterbalancing force for doors of various weights and various displacements between open and closed position. Thus it will be appreciated that the present invention greatly increases the applicability of a single size of spring to doors of various weights and various heights of travel between closed and open position. This makes possible a substantial reduction in the number of sizes of springs required to be stocked, while permitting easy and convenient adjustment of an overhead door at the point of installation to provide any desired type of operation. The spring adjuster is simple and rugged in construction, and is thus economical to manufacture while being capable of operating indefinitely Without attention after being installed.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein de scribed and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

I claim:

1. In an overhead door having a support, a rotatable shaft journaled in the support, a spring anchor connected to the support, and a torsion counterbalance spring surrounding the shaft and connected at one end to the spring anchor, means for adjusting the rate of the spring comprising a projecting pin on the shaft about which the other end of the spring is hooked, an axially adjustable cylindrical sleeve on the shaft having one end extending a selected amount within said other end of the spring, said sleeve having an outside diameter substantially equal to the inside diameter of the spring in an unstressed condition and having an axial slot accommodating said pin, angularlyspaced longitudinal ribs on the inside surface of the sleeve slidably contacting said shaft, and means for securing said sleeve in selected axial position on the shaft including a setscrew carried by the sleeve and engageable with the shaft.

2. In an over head door mechanism having a support, a rotatable shaft journaled in the support, a torsion counterbalance spring surrounding the shaft and connected at one end to the support, and a connector securing the other end of the spring to the shaft, means for adjusting the rate of the spring comprising an axially adjustable sleeve slidably mounted on the shaft and having one end thereof extending a selected amount within said other end of the spring, said sleeve being axially movable relative to said spring and said connector when said spring is in an unstressed condition.

3. In an overhead door mechanism having a support, rotatable shaft journaled in the support, a spring anchor connected to the support, a torsion counter-balance spring surrounding the shaft and connected at one end to the spring anchor, and a connector securing the other end of ti e spring to the shaft, means for adjusting the rate of the spring comprising an axially adjustable sleeve slidably mounted on the shaft and having one end extending a selected amount within said other end of the spring, said sleeve being axially movable relative to said spring and said connector when said spring is in an unstressed condition, said sleeve having an axially extending opening accommodating said connector, and means for securing said sleeve in selected axial position on the shaft.

4. Spring adjusting means for the torsion couuterbal ance spring of an articulate overhead door of the type having a support, a rotatable shaft carried by the support and surrounded by the torsion spring, a spring anchor connected to the support and to one end of the torsion spring, and a connector securing the other end of the spring to the shaft, said adjusting means including an axially justable sleeve slidably mounted on the shaft and having one end extending a selected amount within said other end of the spring, said sleeve being axially movable relative to said spring and said connector when said spring is in an unstressed condition, and means on the other end of the sleeve for securing said sleeve in selected axial position on the shaft.

5. Spring adjusting means for the torsion counterbalance spring of an articulate overhead door of the type having a support, a rotatable shaft carried by the support and surrounded by the torsion spring, a spring anchor con nected to the support and to one end of the torsion spring, and a connecting pin securing the other end of the spring to the shaft, said adjusting means including an axially adjustable sleeve slida'bly mounted on the shaft and having one end extending outwardly from said other end of the spring and the other end of said sleeve extending within the spring, said sleeve being axially movable relative to said spring and said connecting pin when said spring in an unstressed condition, said sleeve having an axial slot to accommodate said connecting pin, and means on its sleeve outwardly of the spring for securing said sleeve in selected axially adjusted position.

References Cited in the file of this patent UNITED STATES PATENTS