GB2178793A - Counterbalance for up-and-over door - Google Patents

Abstract

The counterbalance has at least two pressurised-fluid-extensible struts (17, 18) arranged in series at one vertical edge of the door, which co-act on guide means (13, 13) attached to vertical side edges of the door, through a cable-and-pulley motion-increasing device (22, 23, 24, 26), to tend to move the door from the closed towards the open position. One of the struts may be weighted. <IMAGE>

Description

SPECIFICATION Door assemblies This invention relates to door assemblies ofthe type in which a door closure member moves from a sub stantiallyvertical closed position upwardly to a substantially horizontal open position.

A door assembly having a door closure member that moves from a substantially vertical closed position upwardlyto a substantially horizontal overhead open position is often guided during this movement by spindle and rollerassembliesfixedoneateither vertical side ofthe closure member. Each roller is arranged to run in a vertical guide track which is attached to structure defining an opening in which the assembly is installed, and the closure member pivots aboutthe spindle and roller assemblies during movement between the closed and open positions.

In one such door assembly, as disclosed in GB-A1008917, spring counterbalance mechanism for counterbalancing the weight ofthe closure member during movement between the closed and open positions is housed in the vertical guide tracks and com prisestension springs acting on the closure member through cable and pulley assemblies.

The spring counterbalance mechanism in another such door assembly, as disclosed in GB-1 548 009, comprises a tension spring and compression spring housed within each ofthe vertical guide track members and co-acting to tend to move the closure memberfrom the closed position towards the open position.

Another door assembly of this type, as disclosed in GB-A-1246214,is biased for movementfrom the closed position towards the open position by a pair of gas struts located one at eithervertical side edge of the closure member. Each gas strut acts between a support arm and a pivot a rm . The su pport a rm is secured toe door post at one vertical side edge ofthe opening in which the door assembly is installed, and extends rearwardly of the door arm to pivotal attachment, at its rearward end, with one end of the pivot arm, the other end of which is fixed to the closure member.

According to the present invention a doorassembly including a door closure memberwhich in operation moves between a substantially vertical closed position and a substantially horizontal overhead open position during which movement the closure member pivots about guide means attached to vertical side edge portions ofthe closure memberand arranged for movement in guidetracks adapted for attachment to structure defining vertical sides of an opening in which the door assembly is installed, and counterbalance mechanism for counterbalancing the weightoftheclosurememberduring movement from the closed position to the open position is characterised in that the counterbalance mechanism comprises at least two pressurised-fluid-extensible struts arranged in series at one vertical side edge ofthe closure member and co-acting on the guide means through a cable and pulley motion-increasing arrangementtotendto movethe closure member from the closed position towards the open position.

The pressurised-fluid-extensible struts preferably comprise gas struts each having a piston which is extendiblefrom a cylinder underthe action of gas pressure in the cylinder.

In one embodiment ofthe invention having two gas struts arranged in series the exposed end of the piston of one gas strut abuts with the closed end face of the cylinder of the second gas strut and the exposed end ofthe piston of the second gas strut co-operates with a movable double pulley block ofthe motionincreasing arrangement. In this embodimentthe motion increasing arrangementfdrther comprises two cables each having an end attached to the vertical guide track atthat side ofthe door closure member on which the gas struts are disposed and extending first downwardly to pass around the movable double pul ley blockandthen upwardly to a second double pulley block adapted for attachment to structure at the top ofthe side edge ofthe opening in which the door assembly is installed.One cable passes around the second double pulley block and extends back on itself to have its other end attached to the guide means at that side ofthe closure member on which the gas struts are disposed whilst the other cable passes around the second double pulley block and extends acrossthetop ofthe opening to pass around a single pulley and then extend downwardlyto have its other end attached to the guide means atthe opposite side of the closure member.

The gas struts are preferably housed within the vertical guide tracks which may comprise vertical frame members extending from the bottom tothetop ofthe side edges ofthe closure member and which may be bridged by a horizontal frame member so that the door assembly is provided complete with a frame ready for installation by attachment of the frame to building structure defining the opening in which it is to be installed.

If desired the lower strut in the series may be weighted such as by provision of a cored weight on the exterior of its cylinderto smooth out rate build-up of the gas struts.

A door assembly in accordance with the invention will now be described, byway ofexample only, with reference to the accompanying drawings in which Figure lisa diagrammatic illustration looking on the back face of a door assembly in accordance with oneembodimentoftheinvention,thedoorclosure member being shown in the closed position; and Figure2 is a diagrammatic illustration similarto that ofthe Figure 1 but with the door closure member being shown in the open position.

Referring to the drawings, a door assembly 10 comprises a single panel doorclosure member 11 having guide means which in this embodiment are compris ed by spindle and roller assemblies 12 attached to each of its vertical side edges. Each spindle and roller assembly 12 comprises a spindle 13 mounted in a bracket 1 4which is attached to the back face ofthe closure member 11, and a roller 15 carried on that end ofthe spindle 13 which projects outwardlyfrom the vertical side edge ofthe closure member 11 The rollers 1 5 at each side of the closure member are located in substantially vertically-disposed guide tracks 16 attached to the structure defining the vertic al sides of the opening in which the door assembly is installed.For purposes of clarity, only the guide track at the right hand side ofthe door assembly is shown in the drawings and the guide track is shown cutaway at the location ofthe roller in each ofthe drawings.

Counterbalance mechanism for counterbalancing the weightofthe closure member 11 during move- mentfrom the closed position (as shown in Figure 1) to the open position (as shown in Figure 2) comprises two pressurised fluid extensible struts arranged in series at one vertical side edge ofthe closure member 11 which co-actthrough a cable and pulley motion increasing arrangementto tend to move the closure memberfrom the closed to the open position.

In this embodimentthe extensible struts comprise first and second gas struts 17 and 18 respectively. The firstgas strut 17 has its cylinder constrained against movement by being fixed to structure atthe side edge ofthe opening in which the door assembly is installed such as, for example, the vertical guide track, and has an exposed end 19 of its piston in abutmentwith a closed aend face 20 ofthe cylinder of the second gas strut 18. The second gas strut 18 is arrangedforslid- ing movement in a vertical direction under action of the piston ofthe first gas strut 17 by suitable attachment (not shown) to structure atthe side edge ofthe opening in which the door assembly is installed.An exposed end 21 of the piston ofthe second gas strut 18 co-operates with a movable double pulley block 22 which comprises part ofthe cable and pulley-motion increasing arrangement.

The motion increasing arrangementfurther comprises two cables 23 and 24, only one being visible in the drawings because oftheirsuperimposition, each having one ofthe ends 25 fixed to the vertical guide track at a position above the movable double pulley block 22. From their ends 25 the cables 23 and 24 extend first downwardly to pass around the double pulley block 22 and then upwardly to pass around a second double pulley block 26 which is fixed to struc to rue atthe top ofthe side edge ofthe opening in which the doorassembly is installed.Although not so illus trated in the drawings, the double pulley block 26 is preferably mounted on the upper wend ofthevertical guide track 16 which is disposed on that side ofthe assembly, The cable 23 passes around the double pulley block 26 and extends downwardly to have its opposite end 27 attached to the spindle 13 ofthe spindle and roller assembly 12 on that side ofthe closure memberatwhich the gas struts 17 and 18are located.The cable 24 passes around the double pulley block 26 and extends across the top ofthe opening to pass around a single pulley block 28 mounted on structure atthetop ofthe opposite side edgeofthe opening in which the door assembly is installed and then passes downwardly to have its other end 29 attached to the spindle 13 ofthe spindle and roller assembly 12 on that side of the closure member.

In operation of the door assembly with the door in the vertical closed position as shown in Figure 1 the pistons ofthe gas struts 17 and 18 are retracted within the gas strutcylinders andthe double pulley block22 is in its uppermost position. When door latching mechanism (not shown) is released the gas struts 17 and 18 co-act by movement oftheir pistons outof their cylinders underthe pressure of the gas within the cylinders to move the double pulley block 22 in a downward direction.This movement is transmitted through the cables 23 and 24to apply a force to the spindle and roller assemblies 13 at each side ofthe closure member 11 which causes the closure member 11 to rotate aboutthe spindle and roller assemblies 13 as these assemblies 13 are moved in an upward direction with the rollers 15 running in the guide tracks 16. This movement continues until the pistons ofthe gas struts 17 and 18 are substantiallyfully extended from their cylinders and the double pulley block 22 is in its lowermost position as seen in Figure 2 which the closure member 11 being in the overhead horizontal open position. With the closure member 11 in the open position the rollers ofthe spindle and roller assemblies are disposed at the upper ends of thevertical guidetracks 16.

It will be appreciated that the embodiment of the invention herein before described with reference to and as shown in the accompanying drawings is by way of example only and modifications are possible.

For example, the vertical guide tracks may extend over the full height of the vertical sides of structure defining an opening in which the assembly is installed and they may be bridged by a horizontal frame member so that a framed door assembly is provided with the extensible struts and the cable and pulley motion increasing arrangement being housed within the frame.

Also, to smooth out rate build-up ofthe extensible struts the second strut may be weighted by a cored weight provided on the exterior of its cylinder.

Claims (7)

1. Adoorassembly including a door closure memberwhich in operation moves between a substantially vertical closed position and a substantially horizontal overhead open positon during which movementtheclosure member pivots about guide means attached to vertical side edge portions ofthe closure member and arranged for movement in guide tracks adapted for attachment to structure defining vertical sides of an opening in which the door assembly is installed, and counterbalance mechanism for counterbalancing the weight of the closure member during movement from the closed position to the open position; characterised in that the counterbalance mechanism comprises at leasttwo pressurisedfluid-extensible struts arranged in series at one vertical side edge ofthe closure member and co-acting on the guide means th rough a cable and pulley motionincreasing arrangement to tend to move the closure member from the closed position towards the open position.

2. A door assembly as claimed in claim 1,wherein the pressurised fluid-extensible struts comprise gas struts, each having a piston which is extendible from a cylinder under action of gas pressure in the cylinder.

3. Adoorassembly as claimed in claims 1 or2, wherein the exposed end of the piston of one gas strut abuts with the closed end face ofthe cylinder of the second gas strut and the exposed end ofthe piston ofthe second gas strut cooperates with a movable double pulley block ofthe motion-increasing arrangement.

4. An assembly as claimed in claim 3, wherein the motion-increasing arrangementfurthercomprises two cables, each having an end attached to thevertic- al guide track at that side of the door-closure member on which the gas struts are disposed, and extending first downwardly to pass around the movable double pulley block and then upwardly to a second doublepulley block adapted for attachment to a structure at the top of a side edge the opening in which the door assembly is installed.

5. An assembly as claimed in claims 1 or2,where in the gas struts are housed within vertical guide track which comprise vertical frame members at the sides of the frame within which the door assembly is installed.

6. Adoorassembly as claimed in claims 1 or2, wherein the lower strut of the series is weighted by provision of a cored weight on the exterior of its cylinder, so asto smooth out rate build-up in the gas struts.

7. Adoorassemblyas claimed in claim 1 and substantiallyasshown in Figures 1 and 2 of the accompanying drawings.