Method and apparatus to raise and lower an overhead door

A method and apparatus to raise and lower an overhead door comprising a lift mechanism, a master pulley block, a fixed pulley mounted to the lift mechanism, a plurality of guide sheaves each associated and spaced from with the master pulley block and supported by the elongated support member, and a plurality of cables each having two opposing ends and passing over the fixed pulley and the master pulley block and further passing over an associated one of the plurality of guide sheaves, wherein each cable of the plurality of cables attaches by attachment means to an overhead door.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to large overhead doors and, more particularly, to an apparatus and to a method of raising and lowering an overhead door. In particular, the present invention is directed to an apparatus and method using a power driven pulley assembly to raise and lower an overhead door.

2. Related Art

By way of background, large overhead doors are utilized in a variety of applications, such as in industrial plants and for airplane hangars. The overhead doors are typically fabricated from a metal frame to form a single planar piece which is covered with a metal or other face material. For example, an apparatus and method of construction of an overhead door is disclosed in Applicant's co-pending U.S. patent application Ser. No. 14/066,003 filed Oct. 29, 2013 which is incorporated herein by reference in its entirety.

The overhead doors are very large, and tend to be relatively heavy. Because the overhead doors are fabricated to form one single piece, they cannot bend at hinges like garage doors that are typically used for housing automobiles. Because the overhead doors are large, heavy and cannot bend, lifting or raising the overhead door proves to be difficult.

Accordingly, it would be desirable to develop an apparatus and a method to raise and lower an overhead door that is able to lift the large overhead door as a single piece.

It is further desirable to develop an apparatus and a method to raise and lower an overhead door that could be adapted to raise and lower nearly any size or configuration of overhead door.

It is further desirable to develop an apparatus and a method to raise and lower an overhead door using a hydraulic cylinder.

It is further desirable to develop an apparatus and a method to raise and lower an overhead door using a pulley system.

SUMMARY OF THE INVENTION

The present invention is directed to an apparatus and a method of raising and lowering an overhead door. Generally, the embodiments in accordance with the present disclosure provide a raising and lowering apparatus specifically designed for use with large overhead doors, such as in industrial plants or for airplane hangars, wherein the door is raised and lowered in one solid piece without bending.

In accordance with one example embodiment, the raising and lowering apparatus comprises a lift mechanism, for example, a hydraulic cylinder, for driving a pulley system to raise and lower the overhead door. In one embodiment, the lift mechanism comprises a hydraulic cylinder installed into a building housing the overhead door, wherein the cylinder is positioned to the side of the overhead door in vertical alignment to the ground. A fixed pulley is mounted at the top or end of the lift mechanism. A series of cables extend from the side of the overhead door and up along an elongated support member extending across the top of the overhead door and mounted within the building. Each of the cables is anchored within a master pulley block. The cables pass around a fixed pulley mounted to the lift mechanism, and then pass over a master pulley sheave located within the master pulley block. From there, the cables pass over a plurality of single-grooved guide sheaves. Each individual cable in a plurality of cables is individually associated with an individual single-grooved guide sheave. After an associated individual cable passes over a guide sheave, the individual cable extends tangentially from the guide sheave and downward toward approximately the midpoint of the overhead door. There the individual cable meets with and rests upon a stationary half sheave that is welded onto the overhead door, and inserts into an opening of the overhead door. On the inside of the overhead door the cable attaches to a clamp plate by way of cable clamps.

In operation, the lift mechanism, such as a hydraulic cylinder, is actuated to extend or retract, depending on whether the door is being raised or lowered. If it is desired to raise the door, the lift mechanism is actuated to pull down on a fixed pulley which is mounted to the lift mechanism and is in association with a master pulley block. By retraction of the lift mechanism, the series of cables passing over the fixed pulley are pulled or extended downward in the direction of the ground, thereby tightening and pulling each cable which is individually anchored to the overhead door at respective positions and the force created pulls to lift or raise the overhead door. This arrangement reduces the number of components necessary and allows for the pulleys and lift mechanism to be closely installed to the door opening.

If it is desired to lower the door, the opposite occurs, and the lift mechanism is extended to slowly release slack to a plurality of cables and move the cables and pulleys in the opposite direction, lowering the door.

The overhead door includes two opposed guide rails or tracks, along with two guide rollers on each side of the overhead door. When the lift mechanism pulls the cables over the pulley system, the overhead door is lifted and guided along the guide rails. This arrangement serves to reduce the stress and weight of raising and lowering the overhead door.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in detail,FIG. 1illustrates a perspective view of an overhead door10constructed in accordance with the present invention. The apparatus is shown installed in an opening in a building12having a plurality of building structural beams14. TheFIG. 1view is shown from the inside of the building12.

The overhead door10is shown in a closed or lowered position; however, it may be raised or opened utilizing the method and the apparatus described herein, including a lift mechanism18.

A pair of guide tracks or rails16is arranged on opposed sides of the overhead door10, each having a substantially vertical portion fixed to the building12. The pair of guide rails16curve to form a substantially horizontal portion that extends into the building12. The length of the horizontal portion is only a short portion of the travel of the door frame.

A pair of guide rollers is mounted on either side of the overhead door and aligns and rolls along the guide rails16. This arrangement serves to reduce the stress and weight of raising and lowering the overhead door as well as limits the movement of the overhead door.

An outer face20of the door10has been partially removed for ease of viewing.

A preferred embodiment may further include a stop mechanism micro switch (not shown) placed at a location within each guide rail16to provide a mechanism to stop or block the guide rollers from further movement, and halting the door. The micro switch is connected to and controlled by a control box located on the side of the building.

The overhead door10may further include a pin-lock at the bottom corners on either side of the overhead door to associate with and be received by the building foundation. In use, when the door is lowered and closed, the pin mechanism aligns with an opening drilled in the building foundation. The pin is received by the opening limiting movement of the closed overhead door in the case of strong weather conditions, such as wind.

FIG. 2illustrates a perspective view of a preferred embodiment of the present invention with the face of the door removed for clarity.FIG. 2illustrates how the cables pass over the pulleys and sheaves to lift the overhead door, while the pulleys and component parts are shown enlarged in later figures. TheFIG. 2view is shown from the outside of the building.

In operation, to raise the overhead door, a lift mechanism18is actuated to retract. During retraction of the lift mechanism18, a fixed pulley26, attached to the lift mechanism18, also retracts moving downward. This movement pulls a plurality of cables24downward. The plurality of cables24have an end58which is located and anchored within a master pulley block36. The plurality of cables24extend downward to pass around a fixed pulley26. The plurality of cables24then extend upward where they pass over master sheave34which is in association with fixed pulley26. The plurality of cables24extends longitudinally along elongated support member22to be received by a guide sheave38,44, or50. Each individual cable of the plurality of cables24is associated with an individual single-grooved guide sheave38,44, or50. Thus, the plurality of guide sheaves38,44,50will equal the number of cables in the plurality of cables24. At each single-grooved guide sheave38,44,50, one cable24aof the plurality of cables24passes over a single-grooved guide sheave38,44,50and tangentially extends from the single-grooved guide sheave38,44,50and downward to attach to the overhead door. The remaining cables of the plurality of cables24continue to extend further along an elongated support member22where each remaining cable is similarly received by a subsequent single-grooved guide sheave38,44,50. Similarly, when the cable is received by the single-grooved guide sheave38,44,50, it tangentially extends from the single-grooved guide sheave38,44,50and downward to attach to the overhead door at a designated point and so on until all cables have extended downward over a single-grooved guide sheave and attached to the overhead door at designated points.

By providing a plurality of cables24anchored at end58within a master pulley block36then passed around a fixed pulley26in association with a master pulley block36, a mechanical advantage of 2 to 1 is realized. By extending or retracting the lift mechanism18, the large overhead door can be safely and easily raised or lowered.

Lift mechanism18with attached fixed pulley26is shown inFIG. 3. The lift mechanism shown inFIG. 3is a hydraulic cylinder or ram; however, it may be appreciated that the lift mechanism18may take on other types of lifting mechanisms, such as a pneumatic cylinder or a worm gear. The lift mechanism18is shown in an extended position. In operation, the lift mechanism18either retracts, pulling the fixed pulley26downward to raise the door, or the lift mechanism18extends to lower the door.

The fixed pulley26is fixed by a central axle between a pair of opposing arms32. The pair of opposing arms32creates a means of attachment for the fixed pulley26and the lift mechanism18. Pin30mounts the pair of opposing arms32and the rod of the lift mechanism18together. A brace28may also be mounted by pin30for additional security. Fixed pulley26may comprise a plurality of grooves arranged to receive a plurality of cables24. In one embodiment, fixed pulley26includes six grooves arranged to receive a plurality of six cables, however, it may be appreciated that fixed pulley26may comprise more or less grooves, depending on the particular application. The cables24each have two ends and are typically made of a durable, braided wire, but could also be made of other non-limiting materials.

The master pulley block36is shown in detail inFIG. 4. The master pulley block36includes a housing and a master sheave34rotatably mounted on a central axle. The master pulley block36is mounted into the door frame in association with elongated support member22. Master sheave34may comprise a plurality of grooves arranged to receive a plurality of cables24. In one embodiment, master sheave34includes six grooves arranged to receive a plurality of six cables, however, it may be appreciated that master sheave34may comprise more or less grooves depending on the number of cables and the particular application. The plurality of cables24extend to a plurality of single-grooved guide sheaves, as can be seen inFIG. 5.

Shown inFIG. 5, a fixed pulley26is attached to a lift mechanism18by opposing arms32, brace28, and pin30.

Each of a series or plurality of cables24beginning at terminal end58passes around the fixed pulley26and extends upwards toward a master pulley block36. The plurality of cables24passes over master sheave34, contained within a master pulley block36, and extends longitudinally along an elongated support member22. A plurality of single-grooved guide sheaves38,44,50are attached to an elongated support member22and are spaced at a designated distance from the master pulley block36. The spacing of the guide sheaves38,44,50correspond with the location the individual cables are attached to the overhead door. Each of the single-grooved guide sheaves are associated with the master pulley block36and rotate in the same manner.

A first single-grooved guide sheave38housed in block40is shown inFIG. 5. Each individual cable within the plurality of cables24is associated with an individual single-grooved guide sheave. Once the cable passes over its associated guide sheave, it extends tangentially from the guide sheave and downward for attachment to the overhead door. For example, as shown in the Figure, one of the cables in the plurality of cables24passes over guide sheave38and then extends tangentially from the guide sheave, terminating at an attachment point further described herein and shown inFIGS. 9,10and11. The remaining cables of the plurality of cables24extend onward longitudinally along elongated support member22, where another single cable passes over the next guide sheave and terminates downward for attachment to the overhead door, and so on until all the cables in the plurality of cables pass over a guide sheave and terminate downward for attachment to the overhead door in a similar manner.

An individual single-grooved guide sheave38is shown inFIG. 6. The single-grooved sheave38defines a single-grooved cylindrical surface for receiving a single cable and is rotatably mounted on axle42which is connected to housing40. Guide sheave38has one single groove arranged to receive an individual cable from the plurality of cables24. Shown inFIG. 7, the plurality of cables24extends longitudinally along elongated support member22. Guide sheave44receives an individual cable24aof the plurality of cables and it passes over guide sheave44and extends tangentially from the guide sheave44and downward for attachment to an overhead door.

FIG. 8shows a guide sheave50rotating along axle54within housing52.FIG. 8shows the last cable and guide sheave association, wherein guide sheave50receives the last remaining cable of the plurality of cables24. The cable24apasses over guide sheave50and extends tangentially downward for attachment to the overhead door as shown inFIG. 9.

At each single-grooved guide sheave, a cable24aextends tangentially downward and is received by a stationary sheave plate70which is fabricated onto a vertical C-channel member of the overhead door. The cable24aenters the C-channel member through opening64. As better shown inFIGS. 10 and 11, the cable24ais securely fastened to clamp plate60by cable clamps62.

The fastening component includes a clamp plate60with a plurality of pairs of drilled holes. The clamp plate60is welded into a vertical C-channel member of the overhead door. The cable clamps62comprise a threaded bolt, curved with two arms, and brace which are aligned within the plurality of drilled holes. The threaded bolt and brace are inserted through the clamp plate and into threaded nuts, where they are threadably received. The cable is run through the cable clamps62, as can readily be seen inFIGS. 10 and 11, and securely tightened.

Whereas, the present invention has been described in relation to the drawings attached hereto, it should be understood that other and further modifications, apart from those shown or suggested herein, may be made within the spirit and scope of this invention.