Bifold canopy door

Jan. 15, 1946. r. s. mehard 2,393,052

BI-FOLD CANOPY DOOR

Filed March 13, 1945 3 Sheets-Sheet 1

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Jan. 15, 1946. r. s. mehard 2,393,052

ΒΙ-FOLD CANOPY DOOR

Filed March 13, 1945 3 Sheets-Sheet 2

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R. S. MEHARD 2,393,052

BI-FOLD CANOPY DOOR

Filed March 13, 1945 3 Sheets-Sheet 3

Jan. 15, 1946.

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Patented Jan. 15, 1946

2,393,052

UNITED STATES PATENT OFFICE

2,393,052

BIFOLD CANOPY DOOR

Robert S. Mehard, Youngstown, Ohio, assignor to Truscon Steel Company, Youngstown, Ohio, a corporation of Michigan

Application March 13, 1945, Serial No. 582,547

Claims. (Cl. 160—185) '

This invention relates to doors, and has particular reference to improvements in so-called “bi-fold” doors of the type comprising an upper leaf which is pivoted at or near its upper end to a building structure, at or near the top'of a doorway therein, for upward and outward swinging movement from a vertically disposed, closed position to a substantially horizontally disposed, open position in which it extends, canopy-like, from the building structure at the top of the doorway, and a lower leaf which is pivotally connected at or near its top to the upper leaf near the bottom thereof for inward and upward swinging movement relative to the upper leaf from a vertically disposed, closed position to an open position in which it underlies the upper leaf when the latter is open.

While the doors of the general type mentioned are known, their designs heretofore have been such that they are quite heavy and require considerable expensive fabrication. Accordingly, one special and important object of the present invention is to provide a door of the type mentioned which, comparatively speaking, is of light weight, much simplified design, and which may be produced with little fabrication and, therefore, economically, in most part from standard structural elements such as I-beams, channel members and the like.

Another special and important object of the present invention is to provide a door of the type mentioned embodying a simple leaf-movementcontrol-mechanism which is effective to hold the leaves securely in both their open and their closed positions and which also is effective to cause the lower portion of the lower leaf to move directly vertically during initial opening and final closing movement of said leaf, thereby to adapt said leaf for free and easy engagement with and disengagement from simple keeper means at the bottom of the doorway and to insure that snow or the like which may become packed against the lower part of the lower leaf will not interfere with opening and closing of the door.

Another special and important object of the invention is to provide a leaf-movement-controlmechanism which is conducive to distribution of stresses throughout the door and to free and easy operation of the latter.

Another special and important object of the invention is to provide spring means to assist in initiating opening movement of the door and to cushion opening and closing movements thereof, thus to eliminate undesirable shocks to which the door might otherwise be subjected.

With the foregoing and other objects in view, which will become more fully apparent as the nature of the invention is better understood, the same consists in a door of the type mentioned embodying the novel features of construction, combination, and arrangement of parts as will be hereinafter more fully described, illustrated in the accompanying drawings and defined in the appended claims.

In the accompanying drawings, wherein like characters of reference denote corresponding parts in the different views:

Figure 1 is a vertical section through a door constructed in accordance with one practical embodiment of the invention and showing, in full lines, the leaves in their vertically disposed, closed positions and, in dotted lines, different positions assumed by said leaves during opening and closing of the door.

Figure 2 is an enlarged, fragmentary section, similar to Figure 1 showing in detail the pivoted, slidable connection between the door leaves.

Figure 3 is a rear elevation of the structure shown in Figure 2.

Figure 4 is an enlarged vertical section similar to Figure 2.

Figure 5 is a cross section on the line 5—5 of Figure 4; and

Figure 6 is a view similar to Figure 2 showing the leaves in partly opened positions.

Referring to the drawings in detail, A designates a part of a building structure such, for example, as an aircraft hangar, having a doorway a, and B designates, generally, a door constructed, mounted and operable in accordance with the invention to control closing and opening of said doorway a.

The door B is composed of an upper leaf b and a lower leaf b', and, in accordance with the invention, the upper leaf b is pivoted, at or near its top, to the building structure A, at or near the top of the doorway a therein, as indicated at 10, for swinging movements between a vertically disposed, closed position, as shown by full lines in Figure 1, and a substantially horizontally disposed, open position in which it extends, canopylike, from the building A, as shown by dotted lines in Figure 1. On the other hand, the lower leaf b' is suitably connected, at or near its top, to the upper leaf b, near the bottom of the latter, both for limited vertical movemeiats; relative thereto and for swinging movements relative thereto between a vertically disposed, closed position and a substantially horizontally disposed open position in which it underlies said upper leaf b when the

2,393,082 latter is in its open position. In this latter connection, depending upon the width of the door, there may be any desired number of vertically slidable, pivoted connections between the leaves at any desired locations spaced apart along the width of the door.

Further in accordance with the invention, the leaves b and b' are connected together and to the building structure A by arm and link assemblies to brace the leaves and to assist in controlling their opening and closing movements, and, as in the case of the connections between the leaves, there may be, depending upon the width of the door, any desired number of these arm and link assemblies spaced apart as desired along the width of the door. In any event, the connections between the leaves are duplicates of one another and a description of one therefore will suffice for all. Likewise, the arm and link assemblies are duplicates of one another and a description of one of these will suffice for all.

While the leaves b and b' may be of any suitable constructions they include vertically disposed, alined I-beams 11 and 12, respectively, and in accordance with the specific embodiment of the invention illustrated in the drawings, any given vertically slidable, pivotal connection between said leaves includes a pair of spaced apart channel members 13, 13 suitably fastened rigidly at their lower ends to the upper end of an I-beam 12 of the lower leaf and rising therefrom behind the lower portion of the related I-beam II of the upper leaf.

Extending through the upper end portions of the channel members 13, 13 is a shaft 14 upon which is mounted, between said channel members, a roller 15 which engages the rear face of the related I-beam II of the upper leaf b, while mounted upon the end portions of said shaft 14 are angle members 16, 16 having flanges 17 which overlie the front face of the rear flange of said I-beam 11. These angle members 16 thus are prevented from moving rearwardly relative to the I-beam 11, but are vertically slidable with respect thereto, and since the channel members 13, 13 are pivotally connected with said angle members by the shaft 14, it follows that the lower leaf b' is connected adjacent to its top to the lower portion of the upper leaf for vertical sliding and pivotal movements relative thereto.

Fixed to the lower portion of the I-beam 11 and extending rearwardly therefrom, one to either side of the channel members 13, 13, is a pair of plates 18, 18 which carry, at their inner sides upwardly and rearwardly inclined cams 19, 19, respectively, while mounted upon the channel members 13, 13, at the outer sides thereof, are rollers 20, 20 for cooperation with said cams, respectively, during initial opening and final closing movements of the door.

Any given arm and link assembly comprises, according to the specific embodiment of the invention illustrated in the drawings, an arm 21 pivoted at its upper end to the building structure A a suitable distance inwardly from the doorway a at about the level of the top thereof, as indicated at 22, and a pair of links 23 and 24, each pivoted at one end to the lower end of the arm 21, as indicated at 25, and pivotally connected at their opposite ends to the upper and the lower leaves b and b', respectively, as indicated at 26 and 27, respectively. As shown, each link 23 and 24 comprises two arms, but either or both of said links may comprise only a single arm if desired. In any event, when the door is closed the lower end of the arm 21 is spaced rearwardly from the door and is disposed at about the level of the bottom of the upper leaf, while the links 23 and 24 extend upwardly and forwardly and downwardly and forwardly, respectively, from the lower end of said arm 21 to the leaves b and b', respectively, to which they are connected at points spaced suitably above the bottom of the upper leaf and suitably below the top of the lower leaf, respectively. Moreover, when the door is closed, the arm 21 is inclined upwardly and rearwardly. Accordingly, each arm and link assembly constitutes a truss effectively holding the upper leaf against swinging inwardly, at its bottom and the lower leaf against swinging inwardly at its top when the door is closed.

When the door is closed the rollers 20, 20 are disposed in front of and against the cams 19, 19 at the bottoms thereof, and the top of the lower leaf b' is spaced downwardly a suitable distance below the bottom of the upper leaf b, the space between said leaves then being closed by an apron 28 depending from the lower end of the upper leaf into Overlapping relationship to the top of the lower leaf. Thus, when the door is closed, the lower leaf is capable of being raised a limited distance relative to the upper leaf. In this connection, suitable door operating means is provided and may comprise one or more cables 29 connected to the bottom of the lower leaf, as indicated at 30, and extending over one or more sheaves 31 to a suitable power or manually operated drum (not shown) located wherever desired, the sheave or sheaves 31 being mounted upon the building structure A a suitable distance above the doorway a and preferably spaced a suitable distance inwardly therefrom.

The inclination and height of the cams 19 is such, in relation to the length of the arm 21 and 40 the lengths of the links 23 and 24, that as the lower leaf b is lifted from its lowermost or closed position, its lower end portion is constrained to move vertically a predetermined distance before it may shift either inwardly or outwardly. In other words, during initial raising of the lower leaf, the link 24 swings upwardly and outwardly about its pivotal connection with the lower end of the arm 21 and thereby causes the top of the lower leaf to swing outwardly, which in turn causes the lower end of the upper leaf b to swing outwardly due to the slidable, pivotal connection between the leaves. At the same time, this outward swinging movement of the top of the lower leaf and the bottom of the upper leaf is controlled by the engagement of the rollers 20 with the cams 19 and by the arm 21 and the links 23 and 24 so that for a given amount of initial upward, opening movement of the lower leaf b', its lower end is constrained to move vertically without shifting laterally. The amount of this initial vertical movement of the bottom of the lower leaf may be predetermined by a proper selection of the lengths of the arm 21 and the links 23 and 24 and by a corresponding proper inclination of the cams 19. In any event, it preferably is sufficient to permit the bottom of the lower leaf to rise above or clear any normal or expected height of snow or the like before the bottom of said leaf partakes of any inward or outward movement. It is, moreover, sufficient to permit complete disengagement of the lower leaf from any locking means with which it may be engaged at its bottom when the door is closed. The provision of suitable locking means for the bottom of the lower leaf thus is simplified and

3,393,052 said locking means may simply consist, for example, of a rail 32 fastened to the floor of the building at the bottom of the doorway a and receivable in a channel member 33 carried by the lower leaf b' at the bottom thereof.

As the lower leaf b' is raised, the roller 15 rolls upwardly over the rear face of the I-beam 11 and the rollers 20 roll upwardly over the front faces of the cams 19 until they reach the tops of said cams, whereupon further control of swinging movement of the leaves by said cams ceases and devolves solely upon the arm 21 and the links 23 and 24. In this connection, it will be apparent that as raising of the lower leaf progresses, the roller 20 will ride over the tops of the cams 19 and leave the same; that the upper leaf will be swung upwardly and outwardly; and that the lower leaf will be swung upwardly and inwardly into underlying relationship to said upper leaf until the leaves reach their fully open positions in which they extend substantially horizontally, canopy-like, from the building structure A above the doorway a.

During opening of the door the lower leaf b' will tend to continue to move upwardly relative to the upper leaf even after the cam rollers 20 have been moved over and have become disengaged from the cams 19, and this tendency will continue as long as the angle between the leaves is obtuse. When, however, the angle between the leaves begins to become acute, the tendency of the lower leaf will be to shift toward the bottom of the upper leaf. In this connection, it is, of course, desirable to limit shifting movements of the lower leaf relative to the upper leaf, and while any suitable means may be provided for this purpose, one suitable and practical means may comprise suitable upper and lower stops 34 and 35, respectively, fastened to the I-beam 11 to be engaged by the roller 15.

Although not essential, suitable spring means preferably is provided to resist downward movement of the lower leaf relative to the upper leaf, thus to avoid shocks due to the roller 15 contacting the stop 34 during opening of the door and due to the bottom of the lower leaf engaging its keeper means at the bottom of the doorway during final closing movement of said lower leaf. In this connection and according to the specific construction illustrated in the drawings, a pair of helical tension springs 36, 36 are connected at their lower ends to the angle members 16,16 respectively, and at their upper ends to the ends, respectively, of an arm 37 which is suitably suspended medially and pivotally from the upper leaf b. Accordingly, said springs tend to yieldably resist and to cushion downward movements of the lower leaf relative to the upper leaf both during opening of the door, as the leaves begin to assume an acute angular relationship to each other and during closing of the door as the lower leaf partakes of the final portion of its downward or closing movement. Moreover, since said springs are in tension when the door is closed, they obviously assist in initiating upward or opening movement of the lower leaf b'.

The arm 37 may be suspended by a rod 38 from a bracket 39 by which the link 23 is connected to the upper leaf b, and said rod may be vertically adjustable relative to said upper leaf by a nut 40, whereby the effective strength of the springs 36 may be varied.

When the cable or cables 29 is or are released, the door gravitates to closed position and the leaves simply partake of the reverse of their opening movements, the rollers 20 beginning to cooperate with the cams 19 during the final portion of closing movement of the door to insure that the final portion of the closing movement 5 of the bottom of the lower leaf shall be directly downwardly.

Preferably each I-beam 12 is provided at its inner side and adjacent to its bottom with a suitable bumper 41 to engage the under side of the 10 related arm 21 when the door is fully opened, thus to limit upward movement of the leaf and thereby prevent the door from becoming locked in its fully open position.

From the foregoing description considered in 15 connection with the accompanying drawings, it is believed that the construction and operation of the present door will be apparent. It is likewise believed to be clear wherein the present construction accomplishes the objects hereinbefore stated. 20 It is desired to point out, however, that while only a single specific construction has been illustrated and described, the invention is readily capable of embodiment in specifically different constructions within its spirit and scope as defined in the ap25 pended claims.