US 3094163 A
Description (OCR text may contain errors)
June 18., 1963 J. 5. HERBEIE 3,094,163
COUNTERWEIGHTED UPWARD ACTING DOOR panama-panama;
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Filed Oct. 3. 1961 United States Patent "ice" Filed Oct. 3, 1961, Ser. No. 142,594 1 Claim. (Cl. 160-190) The present invention relates to improvements in upwardly acting doors and particularly to an improved counterbalancing arrangement for supporting a portion of the weight of the door for aiding in raising it and for changing the counterbalancing force as the door is raised.
Upwardly acting doors are supported on rollers guided in tracks at the ends of the doors, and the doors are usually constructed of a number of horizontal sections hinged to each other. The guide track extends upwardly and turns horizontally inwardly away from the door opening so that the sections of the door will move upwardly and horizontally following the contour of .the track. As the door moves onto the horizontal portion of the track andincreasing proportion of its total weight is supported by the track. In order to properly counterbalance an upwardly acting door the counterbalance should reduce its force or lose power in the same ratio as the door loses weight to the overhead track. In other words, the effective force of the counterbalance means on the door should change as the unsupported weight of the door changes.
Counterbalancing forces have been applied by spring balances which have not been fully satisfactory in doors which encounter excessive repeated use, which causes failure of the springs. In a high lift door, the door is raised vertically an appreciable distance before its top section goes onto the horizontal track and therefore the unsupported weight of the door does not change for a substantial portion of its vertical movement. In these installations'it has been customary to use a tapered drum on a torsion spring shaft for winding a cable attached to the door. The large end of the drum provides an increased lever arm between the torsion springattached to the shaft, and'the cable, so that the spring does not lose power as fast as when the cable is on the small end of the drum. When the cable is unwound from the drum to reach the small end the door loses weight to the horizontal track and the spring therefore loses power. This arrangement requires the provision of shaped drums and. suffers disadvantage of failure of springs with excessive repeated use.
An object of the present invention is to provide overhead door counterbalancing means which is not affected by repeated use and does not lose its efiiciency orchange its force characteristic and require adjustment, even after excessive use beyond the point where spring counterbalance's fail.
A further object of the invention is to provide an upwardly acting door which is counterbalanced with the use of counterweights arranged to provide a counterbalance that loses power in the same ratio as the door looses weight and to an overhead track.
A still further object of the invention is to provide an improved counterbalancing weight arrangement for an overhead door wherein the counterbalancing force applied to the door varies as a function of door position to compensate for door sections of different weights.
A still further object of the invention is to provide a counterbalanced upwardly acting overhead door wherein the coun-terbalancing force can be selectively varied for different positions of the door by the addition of individual weights.
Other objects and advantages will become more apparent with the teaching of the principles of the invention inconnect ion with the disclosure of the preferred embodi- Patented June 18, 1963 ments thereof in the specification, claim, and drawings in which:
FIGURE 1 is an elevational view of an upwardly acting overhead door, taken from the rear of the door, showing a door counterweighted in accordance with the principles of the present invention;
FIGURE 2 is a vertical sectional view taken substantially along line II-II of FIGURE 1;
FIGURES 3, 4 and 5 are detailed enlarged perspective views of portions of the counterweighting mechanism;
FIGURE 6 is an elevational view taken from the rear of'an overhead door illustrating another arrangement for the counterweighting mechanism; and
FIGURE 7 is a fragmentary top plan view, with portions broken away and portions omitted for clarity, showing an arrangement of sheaves for positioning counterweights at only one side of the door.
As shown on the drawings:
FIGURES 1 and 2 illustrate an upwardly acting door 10 having a plurality of rectangular sections hingedly attached to each other. The bottom panel or section is shown at 11 and the top panel or section at 12 with hinges 13 between'each of the sections.
The door is guided in movement between a closed position, as shown in FIGURES 1 and 2, and a raised position wherein it will be located overhead, by tracks 15 and 16 which are suitably mounted on a rigid door frame 14 beside the door opening. The tracks 15 and 16 each are provided with a vertical potrion 15a and 16a and an overhead horizontal portion 15b and 16b. The door 10 is supported on the tracks by brackets 17 which are located at the hinged interconnection location between each of the door section. The brackets support rollers, not shown, on pins on the brackets, and the rollers ride in the hollow tracks 15 and 16 in a manner which will be fully appreciated by those versed in the art.
It will be apparent that the vertical unsupported Weight of the door becomes less as the door sections are pushed up into the horizontal portions 15b and 16b of the tracks. For counterweighting the door, an overhead horizontal shaft 18 is provided with sheaves or drums 19 and 20 and is supported on bearinged brackets 21 mounted on the door frame 14. Wound .on the drums 19' and 20 are cables 22 and 23 which are secured to plates 24 and 25 attached on the lowermost panel 11 of thedoor.
A .counterweighting torque is applied to the shaft 18 by sheaves or drums 26 .and 27 with cables 28 and 29 wound thereon and attached to counterweight assemblies 30 and 31. In the arrangement of FIGURES 1 and 2, the assemblies at each side of the door are of substantially the same construction and. therefore only the assernbly 3 1 of FIGURE 2 need be described in detail. The counterweight assemblies 30 and 31 are uniformly mounted and .attachedto. the shaft 18 soasto apply a substantially equal torque at each end of the shaft. In some circumstances it may bedcsirable ;to use a single counterweight assembly at one end of the shaft, which of course will be designed to apply a torque to provide thedesired counterweighting force.
The counterweight assembly 3 1 includes a plurality of counterweighting links, such as shown at 32, 3.3, .34 and 35. These links are flexibly attached to each other and are shown in further detaiLinFIGURES 3 through '5.
The flexibly attached links .in effect form a flexible cab-le'means which iszloopedor draped downwardly with the lower end anchored to the 'doorframe and the upper end connected to the door. The upper end' is not directly connected to the door but is, in the arrangement of FIG- URES 1 andZ, connected to the -door through the shaft 18 and the drums carried thereon with the cables over the drums.
The counterweighting links, as illustrated by the links 32 and 33 in FIGURE 4, and by the link 34 in FIGURE 3, are formed of flat plates with separated cars 37 projecting from the links 32 and 33, and coacting separated ears 38 projecting from the links 33 and 34. The cars 38 are more widely separated than the cars 37, and each of the ears is laterally drilled so that pins 39 can be extended through the laterally drilled openings to pivotally interconnect the links. The pins are shown provided with washers 40 at the end and can be upset or peened over at their ends for permanent interconnection. The end link 34, FIGURE 3, is provided with a pin 41 for convenient attachment of the cable 29 which passes over .the drum 27 on the shaft 18.
The lowermost link 35, FIGURE 5, is pivotally interconnected to an anchoring plate 36 which is bolted to the door frame 14.
As the door is raised, the shaft 18 in FIGURE 2 turns in a clockwise direction and the counterweighting linkage 31 loops downwardly. As the door travels upwardly the uppermost door section 12 and the succeeding sections travel up to be supported by the horizontal portion 161; of the track so that the unsupported weight of the door is reduced. At the same time the cable 29 lowers so that the counterweighting linkage drapes further downwardly and a greater number of the links are supported by the anchoring plate 36. Thus a fewer number of links will be supported by the cable 29 and the counterbalancing force will be gradually reduced.
A feature of the invention is the provision of means for control-lably varying the change in counterbalancing force applied to the door so that it is a non-linear function of the movement of the door. This is accomplished by auxiliary or piggyback weights on the links at selected locations. This is especially helpful in installations where some of the panels may be of different weight than others, such as where some panels carry design decorations, heavy windows, or the like. As these panels or sections go on to the overhead horizontal portion of the track b and 16b, they will relieve a higher proportion of the weight from the remaining vertical section of the door than the other sections. If a spring counterbalance were used, an uneven lift ratio would result, but the use of piggyback weights makes possible a perfect counterbalancing in all positions of the door.
As shown in FIGURES 3 and 4, each of the links 32, 33 and 34 is provided with a stud 42 projecting therefrom. The piggyback weights 43 are provided with a hole 45 for slipping over the stud and have a fiat lower surface for mounting on the flat links. When the weights are in place, nuts 44 are turned on to the threaded studs to hold the weights in place.
The additional piggyback weights will be attached to the links at locations to correspond with the heavier panels of the door. In other words, if one of the center panels of the door is of heavier weight than the others, the links will be attached so that they will be at the lower end 46 of the loop formed by the links just as the heavier panel is passing up on to the horizontal portion of the track. Thus, just as the weight of the heavier panel is transferred on to the horizontal track so that it no longer constitutes unsupported door weight, the weight of the piggyback links will be transferred to the anchor 36 and no longer apply a lifting force to the door.
The pins or the pintles adjoining the adjacent links are only subjected to bearing wear at the lower end 46 or bottom of the loop or catenary between the supported and unsupported runs of the linkage. At this point of rotation of the pins they are at the most only supporting two links. Thus the unit is capable of an extremely long operating life which requires no servicing attention.
As an example of construction, in an overhead door links about six inches wide weighing about eight pounds are employed, and auxiliary or piggyback weights on the order of twelve pounds may be used. The links are arranged so that a plurality thereof in effect support each of the panels and therefore a selected number of piggyback weights can be attached to these links depending upon the extra weight of the panel which must be compensated. Conventional overhead door panels are 24 inches in height, and since the counterweight linkage travel is only one-half the height of the door, counterweight links which are six inches high provide for a smooth transition from the suspended counterbalancing position to the door jamb supported anchor. Thus as a 24 inch panel moves from the vertical position to the horizontal overhead position, the counterweight linkage will only drop 12 inches. While the links could be 12 inches high, it is preferred to divide them into two 6 inch lengths for smoother action. The door panel height is preferably selected as a multiple of the links.
FIGURES 6 and 7 illustrate an arrangement wherein a single counterweight linkage at one side of a door evenly counterweights an overhead door. A multi-panelled overhead door 50 is shown supported on rollers in tracks 51 and 52. A counterweight-mg force is applied by cables 53 and 54 secured to plates 55 and 56 on the lower panel of the door.
The first cable 53 on the first side of the door passes upwardly over sheaves 58 and 59, FIGURES 6 and 7, and is connected to the top end of a counterweighting linkage 60.
' The cable 54 at the second side of the door extends upwardly over a sheave 61 and is also connected to the uppermost link of the counterweighting' linkage 60. The
siheaves are supported on frame members 57 above the oor.
The individual links of the counterweighting linkage 60 are of the same construction as illustrated in FIGURE 4 although the weight will be doubled.
FIGURE 6 also illustrates a high lift door. In this arrangement, the vertical portions of the tracks 52 and 53 extend substantially upwardly above the door before the horizontal portions of the track are reached. This requires a substantially constant counterbal-ancing force for the first portion of travel of the door and only when the door reaches the horizontal sections of the track will a diminishing counterbalancing force be applied. To accomplish this function, the lower end of the counterbalancing linkage 69 is connected to a relatively lightweight cable means 61a shown in the form of a chain. The lower end of the chain is secured to an anchor 62 mounted on the door frame. Thus the weight of the linkage 60 will be applied to the door for the first portion of its movement until the upper end of the lightweight chain 61a reaches the lower portion of the loop or catenary. Only at this point does the anchor 62 begin supporting a ponti-on of the weight of the counterbalancing linkage 60 so as to diminish the weight of the linkage on the cables 52 and 53.
It is to be understood that the high lift door and combined counterweightinglinkage and chain arrangement is shown for convenience of illustration in the single counterweighting chain structure of FIGURE 6. The double 'counterweightiug chain arrangement of FLIGURES 1 and 2 may also be employed with a high lift door by at- .taching a relatively lightweight chain at the lower end of the links as taught in connection with the above description.
Thus it will be seen that I have provided an improved overhead upward lifting door assembly with a counterweighting arrangement which meets the objectives, advantages and features above set forth. The structure is compact and occupies a minimum amount of room at a convenient location beside the door jamb, is inexpensive to construct, and has a very long operating life. The mechanism is reliable and does not require adjustment and once the weight arrangement is determined the characteristic of the weights will not change. Should the weights of the door sections change due to the addition of trim or change in construction, this weight change can be quickly and easily compensated by the addition or rearranging of the attached piggyback weights. Further, a single unit can be produced for doors of difierent characteristics, so that a minimum size range of counterweights need be kept in stock, and variations in door weights can be compensated for by change in arrangement of piggyback weights.
The drawings and specification present a detailed disclosure of the preferred embodiments of the invention, and it is to be understood that the invention is not limited to the specific forms disclosed, but covers all modifications, changes and alternative constructions and methods falling within the scope of the principles taught by the invention.
I claim as my invention:
An overhead door assembly with guide tracks for the door having a vertical portion leading upwardly and a connecting horizontal portion with the horizontal portion supporting an increasing portion of the weight of the door as it moves onto the horizontal portion comprismg:
a series of flexibly interconnected counterbalancing weights with a first end being connected to the door, an anchor,
a lightweight flexible cable means connecting the second end of said series of weights and said anchor, said flexible cable being sized so that the counterbalancing weight on the door will be unchanged while the entire door moves in the vertical guide 6 tracks and the counterbalancing weight will change proportionally when the door begins to move in the horizontal guide tracks, said series of flexibly interconnected countenbalancing weights being termed by a series of links pivotally attached to each other to form a chain, the height of each door panel is a multiple of the length of each link and the chain is so connected that a proper counterbalancing weight proportion 'between the door portion remaining in the vertical guide tracks and the effective chain counterbalancing weight is maintained, weight mounting means on each link, weights selectively mounted on the chain link mounting means, and said weights being readily mounted and removed so that a weight may be mounted and removed without disturbing an adjacent link whereby a multipa-nel door raving panels of diflerent weights may be accommodated with proportional counterweights for each door panel.
References Cited in the file of this patent UNITED STATES PATENTS 1,469,542 Storms Oct. 2, 1923 1,603,379 Dantrick Oct. 29, 1926 2,682,772 Cahill Sept. 4, 1928