This invention relates generally to overhead doors and, more particularly, to an overhead door which is raised to a non-vertical position by a cable connection at the top corners of the doors.
Overhead doors are installed to occlude openings in structures such as warehouses, factories, and other commercial establishments. Typically, such a door is comprised of a series of panels hinged together and moveable between a downward closed position to an upward open position. In the open position, the door may be disposed in a vertical, horizontal or a so called tilt-back or oblique position.
In the simplest form, wherein the open door is stored in a vertical position above the opening, it is an easy matter to locate the cable drums directly above the vertically aligned tracks such the cables connected to the door remain aligned with the tracks as the door is raised. Thus, it has been possible to connect the cable to the top corners of the door rather than to the bottom corners thereof. A significant disadvantage to the vertical storage arrangement is that the height of the building must be substantially increased to accommodate the raised height of the door. Thus, a more common approach is to support the open door in either an oblique or horizontal position.
Considering first the oblique arrangement, wherein the door, rather than being raised vertically upward, is rolled around an angled track portion and then along a plane that is at an oblique angle with the vertical wall. Since the drum and its connecting cable has traditionally been vertically orientated, the cable has not been able to be secured to the top of the door since it would tend to diverge farther from the vertical plane as it moves to the open position, thereby causing a binding condition such that the door would not be able to be fully opened. For this reason, such an oblique storage arrangement has had the cable attached to the bottom panels of the door such that the cable can remain in the vertical position as the door is raised to an open, non-vertical position.
In the case of a high lift door, wherein the door is stored in a horizontal open position, the binding condition becomes even worse since the door is moving in a direction normal to that of the powering cable. Thus, it has been even more imperative that the cable be connected to the bottom panels of the door such that, as the cable is raised vertically, the upper portion of the door may be diverted to the horizontal position.
The applicants have recognized that various problems occur with such a bottom lift door. This is particularly true where the doors are of a “knock-out” design wherein provision is made for the doors to be temporarily disengaged from their tracks when in the downward position in order to prevent damage to the doors. Such a design is described in U.S. Pat. No. 6,988,528, granted on Jan. 24, 2006 and issued to the assignee of the present invention. It has been recognized that when such a disengagement occurs, since an upward force is being exerted on the lower panels, there is a tendency for the panels to buckle or roll up, a condition which can be both inconvenient and possibly pose a safety hazard. Another inconvenience of such a bottom connected disengageable door is that, in order for the connecting cable not to interfere with the brush structure at the top of the door, it is necessary to connect the cables at positions outward of the brush structure.
A further problem of such a bottom connected door, and one that is recognized as a problem for doors that are not even of the disengageable type, is that it results in a pushing up against the adjacent sections causing a buckling and crimping of those sections rather than a smooth upward movement thereof. That is, the upward moving force is a compression force acting against the gravitational force of each of the sections.
In accordance with one aspect of the invention, a pair of pulleys are mounted on the distal ends of the non-vertically oriented tracks for storing an overhead door in an open position. The cables from the drums are then extended over the respective pulleys and extend along the respective tracks to connect to their respective top corners of the door. Such an arrangement allows for the smooth lifting of the top of a door along the plane of the tracks.
By another aspect of the invention, in order to accommodate the curved portion of the track, as well as the vertical raising of the top portion of the door to this curved portion of the track in some cases, the length of the door is effectively increased by the addition of a plurality of links secured to the upper corners of the door, with the upper links then being secured to the cable extending to the pulley. In this manner, the powering force exerted at the pulley acts along the track and allows the links to move upward and around the curved portion of the track in a smooth and non binding manner.
Referring now to
Mounted to the wall 12, on either side of the door 13 are vertical support members 22 and 23. The door 13 is supportably mounted within the vertical support members 22 and 23 in such a manner which permits the door 13 to be temporarily disengaged from its mounting position when impacted by a substantial force as shown and described in U.S. Pat. No. 6,988,528, having common ownership herewith and incorporated herein by reference. Thus, when the door is in the closed position as shown, the brush structures attached to the side edges 19 and 21 are slideable disposed in the vertical support members 22 and 23, respectively, but are adapted to be “knocked out” of those installed positions if sufficient force is exerted, either inwardly or outwardly against the door 13.
Considering now the movement and support of the door 13 when it is moved to the open position, it will be seen in
As will be seen in
Also, unlike the prior art arrangements, the tracks 24 and 26 have attached near their distal ends, the respective pulleys 33 and 35 by way of the respective brackets 34 and 36. The cable 31 therefore extends from the drum 37 upwardly to the pulley 33 and then downwardly to the shaft 28. Similarly, the cable 32 extends from the drum 38 upwardly to the pulley 35 and downwardly to the other top corner of the door as shown in
In operation, when it is desired to open the door, the drum shaft 39 is caused to rotate by some means such as a drive motor, a counterweight, or torsionial springs, with the cables 31 and 32 then being wound up on the respective drums 37 and 38. This causes the respective cables 31 and 32 to lift the door 13 from its upper corners. The rollers 27 are then allowed to feed into the respective tracks 24 and 26 in the manner as described hereinbefore. It will thus be seen, that as the door is raised, the cables 31 and 32 connected to the top corners of the door will remain substantially in alignment with their respective tracks 24 and 26 during the entire period of raising or closing the door. Such an arrangement therefore allows for the attachment of the cables to the upper corners of the door and therefore overcomes the problems associated with the connections to the lower portions of the door.
It will be seen in
For horizontally stored doors, the bend which the door must transverse as it is raised is not negligible as described hereinabove but is rather a 90° bend which would not allow for a smooth transition between the closed and open positions as discussed hereinabove unless other provisions are made. Accordingly, a horizontally stored door will now be described with the present invention being adapted to accommodate the greater curvature in the track.
As will be seen in
As will be seen in
Considering now the effect of the linkages and their associated rollers, it will be seen in
Referring now to
While the present invention has been particularly shown and described with reference to a preferred mode and alternative embodiments as illustrated in the drawings, it will be understood by one skilled in the art that various changes in detail may be effected therein without departing from the spirit and scope of the invention as defined by the claims.