GB2114637A - Counter balanced overhead door - Google Patents

Abstract

An overhead door has a foldable door leaf comprising two door leaf members (11, 12) which are arranged for constrained movement between lower, substantially vertical closing positions and upper, substantially horizontal opened positions while pivoting around horizontal pivot axes (13, 15). The door is provided with counterbalancing means (18) which are completely carried and supported by the door leaf members (11, 12) and are arranged to generate a torque, acting between said members (11, 12) around the moveable horizontal axis defined by a pivotal connection (15) between said members (11, 12). <IMAGE>

Description

SPECIFICATION An overhead door The present invention relates to an overhead door. More particularly, the invention relates to an overhead door of the kind comprising a door leaf member, which is arranged for constrained movement between a lower, substantially vertical closing position and an upper, substantially horizontal open position while pivoting around a moveable horizontal axis, defined by a pivotal connection between said door leaf member and a suspension member which is arranged for, simultaneously constrained movement between a lower, substantially vertical position and an upper, substantially horizontal position through pivoting around a stationary horizontal axis in a direction opposite to the direction for simultaneous pivotal movement of said door leaf member around said moveable axis, said door further comprising at least one set.of c'ucerbalancing means for said members consisting of a spring or other means for generating an elastic force and a linkage, connected to said force generating means and to said members.

The invention especially concerns doors of said kind having a foldable door leaf, consisting of two door leaf members, comprising an upper door leaf member forming the above-mentioned suspension member and a lower door leaf member which is swingably carried by the upper member.

However, it should be noted that the invention is not restricted to folding doors. Instead, the invention may be applied also on doors having a stiff door leaf consisting of a single door leaf member. In this case, said suspension member may preferably be formed by two arms which are swingably mounted at opposite sides of the door opening and pivotally connected to the door leaf at opposite lateral edges thereof.

One of the drawbacks encountered in connection with prior art doors of the above kind is that the linkages used for counterbalancing purposes have been of very bulky construction causing them to project substantial distances from the door leaf, both in the open and in the closed position of the door. Hereby the free space behind the door has been undesirably restricted.

Additionally, it has also been necessary to dimension the height of the door opening substantially lower than the ceiling height of the room located behind said opening in order to provide the required space for accommodating the linkages.

The invention has for its purpose to provide an improved overhead door of the kind initially specified which avoids the above disadvantages as well as other drawbacks of prior art doors of said kind. According to the invention, for this purpose, there is provided a door of said kind which is characterized primarily in.that said counterbalancing means are completely carried and supported by said two members and arranged to generate a torque, acting between said two members around said moveable horizontal axis.

By carrying and supporting the counterbalancing means solely by means of said two members, as suggested according to the invention, it is possible not only to avoid that the counterbalancing means will project substantially from said members. Instead, it is also possible to simplify the installation of the door considerably, as it will no longer be necessary to effect any connections between various parts of the counterbalancing means and the door frame or other stationary building portions.

Said linkage may suitably comprise means for reversing the direction of said torque when said two members approach their lower, substantially vertical positions. Hereby, the counterbalancing means which tend to move the door leaf towards its open position within the major portion of the region of movement of the door leaf and which are arranged to maintain the door leaf in said position, may also serve to maintain the door leaf in its closed position. Said torque reversing means may preferably be formed by a toggle joint having a dead-centre position which said toggle joint will pass when said two members approach their lower positions.

In a preferred embodiment of the invention, said linkage comprises a lever, swingably mounted on one of said two members, near the pivotal connection between said two members, and a rod which is swingably mounted on the other member at its one end while it is pivotally connected to said lever at its other end, said rod acting alternatingly as a push rod and as a pull rod depending on the instantaneous positions of said two members.

Below the invention will be described in further detail, reference being had to the accompanying drawings, in which: Figure 1 is a side elevation of a door according to an embodiment of the invention, selected by way of example, showing the door leaf in a partially opened position, while Figure 2 is a diagrammatic side elevation of the door, wherein the door leaf has been shown in full lines in its closed position and in dash-dotted lines in its open position.

The door shown in the drawings comprises a foldable door leaf, consisting of an upper door leaf member 11 and a lower door leaf member 12. At its upper end, the upper door leaf member 11 is swingably mounted in a door frame 14 by means of bearing bolts 1 3 so as to be able to be swung around a stationary horizontal axis, defined by said bolts 13, between a lower substantially vertical position and an upper substantially horizontal position. At its upper end, the lower door leaf member 12 is connected to the upper door leaf member 11 by means ofa pivotal connection 15, defining a moveable horizontal pivot axis for the lower door leaf member 1 2 around which this door leaf member may be swung relatively to the upper door leaf member 11.

The two opposite'vertical lateral portions of frame 1 4 are provided with opposed longitudinal guide grooves 1 6. These guide grooves 16, which are provided with longitudinally extending openings facing each other, serve as guides for two guide pins or rollers 1 7 provided in axially aligned positions at opposite lateral edges of the lower door leaf member 12 and projecting each into one of said guide grooves 1 6. Said guide pins or guide rollers 1 7 define an additional horizontal pivot axis for the lower door leaf member 1 2.

Through cooperation between guide grooves 1 6 and guide pins or rollers 17, the movement of door leaf members 11 and 12 will be constrained in a manner so as to ensure that said members will be swung in mutually opposite directions around their pivot axis formed by bearing bolts 1 3 and pivotal connection 15, respectively. This means that, when the upper door leaf members 11 is swung from its lower substantially vertical position to its upper substantially horizontal position, the lower door leaf member 1 2 will simultaneously be swung from a lower substantially vertical closing position to an upper substantially horizontal open position.

At each of its two lateral edges, the door leaf is provided with a counterbalancing device generally designated 1 8. Within the major portion of the region of movement of the door leaf, each counterbalancing device 18 acts on the two door leaf members 11 and 12 so as to tend to move them to their upper positions. Within certain portions of region of movement of the door leaf, the two counterbalancing devices 1 8 may suitably cause only a reduction of the tendency of the door leaf to move towards its closed position under the action of gravity, while, within other portions of said region, the counterbalancing devices may fully neutralize or even overcome said tendency in order to cause the door leaf to move towards its open position.The latter should preferably be the case within the portion of region of movement of the door leaf adjacent to the open position of the door leaf. Thus, the door leaf may be arranged to be maintained in a stable fashion in its open position by the twc counterbalancing devices 1 8.

Each counterbalancing device 1 8 comprises a pneumatic spring or gas spring 19, a lever 20, a rod 21, a lever 22, and a rod 23. Gas spring 19 acts as a compression spring. By means of a pivot pin 24 one end of gas spring 19 is pivotally connected to the upper door leaf member 11, near the upper end of said door leaf member. At its other end, gas spring 1 9 is pivotally connected to lever 20 by means of a pivot pin 25 at a position between the two ends of said lever. At its one end, lever 20 is swingably carried by the upper door leaf member 11 by means of a pivot pin 26, while, at its other end, it is pivotally connected to one end of rod 21 by means of a pivot pin 27. At its other end, rod 21 is pivotally connected to a web portion 22a of the yoke-shaped lever 22 by means of a pivot pin 28.Lever 22 comprises a shorter leg 22b which has its outer end swingably connected to the upper door leaf member 11 by means of a pivot pin 29, and a longer leg 22c, the outer end of which is pivotally connected to one end of rod 23 by means of a pivot pin 30. At its other end, rod 23 is swingably carried by the lower door leaf member 12 by means of a pivot pin 31.

As mentioned above, gas spring 19 acts as a compression spring. This means that it tends to swing lever 20 in a clockwise direction around pivot pin 26 (according to Figure 1). Rod 21, which constantly acts as a push rod, will hereby transmit a force to lever 22 which, within the major portion of the region of movement of the door leaf, will tend to swing lever 22 in a clockwise direction around pivot pin 29. Hereby, lever 22 will transmit a force to the lower door leaf member 12, over pivot pin 30, rod 23 and pivot pin 31 , tending to bring said door leaf member to move in an upward direction, i.e. in a clockwise direction around pivot connection 15, according to Figure 1.

When the door leaf approaches its closed position, the direction of the torque around pivotal connection 1 5 caused by the counterbalancing devices 1 8 will however change its direction shortly before the door leaf reaches said position.

The counterbalancing devices 18 will then tend to straighten the door leaf instead of folding the two door leaf members 11 and 12 together. Hereby, the counterbalancing devices 1 8 may serve also to maintain the door leaf in a stable way in its closed position. The abovementioned reversal of the direction of the torque applied between door leaf members 11 and 12 around axis 1 5 follows from the fact that rod 21 and lever 22 form a toggle joint having a dead-centre position through which said joint will pass shortly before the door leaf reaches its closed position. In said dead-centre position, the three pivot pins 27, 28 and 29 are located along a common straight line.After having passed the dead-centre position, rod 21 will transm;t a force to lever 22 tending to swing said lever in a counter-clockwise direction according to Figure 1. This means that lever 22 will now apply a pulling force instead of a pushing force on rod 23.

The counterbalancing devices 1 8 above described may be constructed and arranged so as to require a minimum of space. Especially, they may be made such that they will not project to any essential degree from the door leaf when the door leaf is in any of its two end positions, i.e. in its closed position or in its fully open position. When the door leaf is in its closed position, the counterbalancing devices 1 8 may be almost fully received in pockets formed between the door leaf and the door frame. The abovementioned features of the counterbalancing devices have been schematically illustrated in Figure 2.

The invention is not restricted to the embodiment above described and shown in the drawings. Instead, many alternative embodiments are possible within the scope of the invention.

Claims (7)

1. An overhead door, comprising a door leaf member (12), which is arranged for constrained movement between a lower, substantially vertical closing position and an upper, substantially horizontal open position while pivoting around a moveable horizontal axis (15), defined by a pivotal connection between said door leaf member (12) and a suspension member (11) which is arranged for simultaneous constrained movement between a lower, substantially vertical position and an upper, substantially horizontal position through pivoting around a stationary horizontal axis (13) in a direction opposite to the direction for simultaneous pivotal movement of said door leaf member (12) around said moveable axis (15), said door further comprising at least one set of counterbalancing means (18) for said members (11, 12) consisting of a spring or other means (19) for generating an elastic force and a linkage (20--23), connected to said force generating means and to said members, characterized in that said counterbalancing means (18) are completely carried and supported by said two members (11, 12) and arranged to generate a torque, acting between said two members (11, 12) around said moveable horizontal axis (15).

2. A door according to claim 1, characterized in that said linkage (20--23) comprises means (21, 22) for reversing the direction of said torque when said two members (11, 12) approach their lower; substantially vertical positions.

3. A door according to claim 2, characterized in that said torque reversing means are formed by a toggle joint (21, 28, 22) having a dead-centre position which said toggle joint will pass when said two members (11, 12) approach their lower positions.

4. A door according to claim 3, characterized in that said linkage (20--23) comprises a lever (22) swingably mounted on one (11) of said two members, near the pivotal connection (15) between said members (11, 12) and a rod (23) which is swingably mounted on the other member (12) at its one end, while it is pivotally connected to said lever (22) at its other end, said rod (23) acting alternatingly as a push rod and a pull rod depending on the instantaneous positions of said two members (11, 12).

5. A door according to claim 4, characterized in that said linkage (20--23) comprises an additional lever (20), swingably mounted on said one (11) of said two members and pivotally connected to one end of an additional rod (21), which is pivotally connected to the firstmentioned lever (22) at its other end, said toggle joint being formed by said additional rod (21) and said firstmentioned lever (22).

6. A door according to claim 5, characterized in that said means for generating an elastic force consists of a gas spring (19) connected between a mounting (24) on said one (11) of the two members and said additional lever (20).

7. An overhead door constructed and arranged substantially as herein particularly described with reference to the accompanying drawings.