Abstract: An insulated glass assembly has internal blinds that are magnetically operated, balanced and can be locked in in place and a front and rear pane of glass having an internal blind assembly therebetween. The internal blind assembly includes first and second pull cords mounted to an upper end of an internal magnetic operator disposed within a side rail which directs the pull cords upward to a fixed connector. The internal magnetic operator is connected to a chain of weights which provide a counterweight for the internal blinds. The internal magnetic operator further has a first plurality of magnets which are disposed in a magnet receiving cavity extending through the internal magnetic operator. A back plate is disposed against the plurality of magnets in the internal magnetic operator.

Abstract: An overhead bi-fold door mounted on a freestanding header has a door lift device with polymer cylindroids and capstans operated with an electric motor driven power transmission to selectively move the bi-fold door from an upright closed position to a folded open position and allow the bi-fold door to move from the folded open position to the upright closed position. Anchors mounted on the bi-fold door adjust the working length of the cylindroids between the capstans and anchors. The capstans have laterally spaced disks engageable with the cylindroids during the helical winding and unwinding of the cylindroid on the capstans as the bi-fold door moves at an increasing rate of speed from the upright closed to folded open positions and a decreasing rate of speed from the folded open to upright closed positions.

Abstract: A garage door carrier system carries an overhead garage door between a closed position blocking entry of a vehicle into a garage, and an open position allowing entry of the vehicle into the garage. The garage door is in rolling engagement with a track that guides the garage door. A lever, rotating about a pivot, has a counterweight at a first end and is rotatably connected to the garage door at a second opposite load end. The counterweight provides in-force at the first end that translates as out-force at the load end as the lever rotates about the pivot to carry the garage door between the closed position and the open position.

Abstract: Embodiments of the resent invention provide an electric motor driven door or barrier opener with a manually operable drive for use in the event of a power failure. The operator includes a manually rotatable drive wheel and manual rotation of the drive wheel effects a movement of at least one drive coupler in generally radially extending direction relative to the drive shaft to effect a drive coupling between the drive wheel and the drive shaft to input drive to permit manual opening and or closing of the door.

Abstract: A system and method for supporting and rotating an axle of an overhead rolling door assembly while replacing a counterbalance spring. A support stand is provided. The support stand is positioned under the overhead door assembly. The overhead door assembly is disassembled enough to expose its main axle. The support stand is adjusted in height to engage the main axle so that the support stand holds the main axle at an elevated position. The broken counterbalance spring is replaced. The main axle is the reinstalled into the overhead door assembly. A pulley wheel is then attached to the main axle. The pulley wheel is turned by winding a cable around the pulley wheel and then unwinding the cable with a winch. This rotates the main axle with the torque needed to properly pre-tension the replacement spring.

Abstract: Door leveling apparatuses are disclosed herein. A door leveling apparatus configured in accordance with one embodiment includes a bracket mounted to a door, such as a vertically-opening sectional door. The apparatus further includes a cable assembly having a first end portion coupled to the bracket and a second end portion coupled to a door lifting system, such as a counterbalance assembly. The first end portion includes an adjuster that enables an operator to adjust the operational length of the cable assembly extending between the lifting system and the bracket, thereby enabling the operator to individually adjust the lengths of two such cable assemblies on opposite sides of the door to align the door with a corresponding opening.

Abstract: A fluid-based spring counterbalance mechanism comprising an elastic flexible fluid-based spring disposed between two surfaces is used to support some or all of the weight of a movable barrier. A linkage mechanism comprising at least one rotating rotatable shaft is configured to receive rotational motion from a jackshaft associated with the movable barrier. A translational mechanism coupled to the at least one rotating shaft and coupled to at least one of the two surfaces is configured to compress the flexible fluid-based spring between the two surfaces in response to rotation of the rotatable shaft. By compressing the fluid-based spring, the counterbalance mechanism provides a force that partially or fully supports the weight of the movable barrier.

Abstract: An apparatus for opening and closing an overhead door, having a door assembly for mounting to the overhead door, and an operator for securely engaging the door assembly. The operator has a chassis, and a cable reel rotatably mounted to the chassis and coupled to a main cable. When the main cable is coupled to the door assembly, as the cable reel is rotated in a first direction, the door assembly is drawn towards the operator so as to close the door. The apparatus may include a latch assembly for securing the door assembly to the operator when the door is closed, and a latch release mechanism for selectively disengaging the latch assembly so as to disengage the door assembly from the operator. The overhead door may be biased so that when the latch assembly is disengaged, the overhead door automatically opens.

Abstract: A counter balance system for an overhead door assembly is provided. The overhead door assembly includes a door frame, an overhead door, and a door lifting assembly. The door lifting assembly includes an extension spring, a cable, and a pulley assembly. The pulley assembly guides the cable as the door is moved between a raised open position and a lowered closed position. A pulley of the pulley assembly is mounted so that an axis of rotation of the pulley remains perpendicular to a portion of the first cable extending between the pulley and a lower portion of the overhead door as the door is moved between the raised open position and the lowered closed position.

Abstract: A pulley assembly for an overhead counter weight door features a base plate and a support arrangement carried on and spaced from the base plate so that the base and support arrangements face toward one another. A shaft is carried on the base plate and the support arrangement to extend therebetween with a pulley supported on the shaft between the base plate and the support arrangement for rotation about an axis defined by the shaft. A plurality of wall sections extends between the base plate and the support arrangement to establish connection therebetween radially outward from the shaft beyond an outer periphery of the pulley on more than two sides thereof.

Abstract: A tilt-up door for a building having a relatively wide door opening having a door frame including top and bottom horizontal members and vertical side members connected to the top and bottom horizontal members. The vertical side members can have a horizontally extending pivot shaft tube positioned between the top and bottom horizontal members, and outwardly extending cam followers adjacent to the top horizontal member. U-shaped channels can extend vertically along opposite sides of the door opening with the U-shaped channels facing each other and the door opening. The U-shaped channels can have generally horizontal track members extending from the top edge of the door opening and the horizontal tracks can have a curved cam surface. Carriages each including a horizontal pivot shaft journal can be positioned in the U-shaped channels for vertical movement in the U-shaped channels.

Abstract: A movable barrier that is at least partially counterbalanced by a spring is moved from a first position to a second position while substantially simultaneously monitoring at least one characteristic associated with moving the movable barrier to provide at least one monitored characteristic. The at least one monitored characteristic is compared to a predetermined criterion. When the at least one monitored characteristic does not meet the predetermined criterion, an alarm condition is set to indicate a failure of the spring.

Abstract: A winding assembly used in conjunction with a door having a counterbalance system operable to offset the weight of the door, the counterbalance system including an axle rotatably supported on a pair of support brackets located at each side of the door and a counterbalance spring adapted to apply a counterbalancing force to the door.

Abstract: An operator for use in connection with a door system including an axle having an operator framework supporting an operator motor, the operator framework defining a clearance adapted to insertably receive the axle therein, a gear assembly defining a bore in which the axle is received and including a removable gear segment adapted to selectively medially open the bore to receive the axle, wherein the motor is interconnected with the gear assembly to cause rotation thereof.

Abstract: A mechanism and method for operating a track-mounted door is disclosed. The mechanism includes a pair of side drums that are connected by first cables to the bottom of the door. The side drums are coaxially mounted on a shaft for simultaneous rotation with a pair of cable drums. The cable drums are connected to high pressure gas struts by second cables. Each second cable is carried around a shiv wheel that slides along a guide track as the second cable moves. Each shiv wheel is operatively connected to one of the gas struts. As the shiv wheel moves along the guide track toward the cable drum, the gas strut is charged. As the shiv wheel moves away from the cable drum, the gas strut is discharged. A standard electric motor and screw driven lift-arm is used to initiate the opening and closing of the door. The charged gas strut stores sufficient energy to overcome friction and gravity to assist the electric motor and lift-arm to open the door.

Abstract: The invention relates to a door comprising a leaf that is movable between an open position and a closed position, a guiding element which is fixed to the door leaf, interacts with a guide rail, and directs the movement of the door leaf, and a locking device that is movable between a released position in which said locking device releases movement of the door leaf and a locked position in which said locking device counteracts movement of the door leaf. The locking device is provided with a locking element which stops at a contact surface of the guide rail when said locking device is moved into the locked position.

Abstract: A balancing and equilibration device for suspended elements, e.g. doors, pieces of furniture, and windows that can be moved vertically, to allow their easy movement and balanced positioning at any point of their vertical travel. Supporting ropes are wound up to be translated in spiroid rims of a pair of opposing pulleys, the pulleys being integral with each other via a shaft rotatable on a bearing structure. The shaft is concentric to a helical spring that includes one end integral with the shaft and another end integral with a friction disc that can be blocked to its support to block the other end of the spring, whose opposite side is bound to turn with the shaft to increase or decrease its torsion reaction with changing movement of the pulleys, to assure balancing of the balanced translation of the element on a frame to be vertically covered or uncovered.

Abstract: An operator for use in connection with a door system including an axle having an operator framework supporting an operator motor, the operator framework defining a clearance adapted to insertably receive the axle therein, a gear assembly defining a bore in which the axle is received and including a removable gear segment adapted to selectively medially open the bore to receive the axle, wherein the motor is interconnected with the gear assembly to cause rotation thereof.

Abstract: An operator for use in connection with a door system including an axle having an operator framework supporting an operator motor, the operator framework defining a clearance adapted to insertably receive the axle therein, a gear assembly defining a bore in which the axle is received and including a removable gear segment adapted to selectively medially open the bore to receive the axle, wherein the motor is interconnected with the gear assembly to cause rotation thereof.

Abstract: A brake device (1) is for use with a cable-operated door (3), such as garage doors (3) and the like. The device (1) is intended to reduce the risk of the door (3) falling, or at the very least slow down its descent, in the event of a failure in the counterbalancing mechanism of the door (3), which is generally represented by a loss of tension in a given tensioned cable (5) operating the door (3). The brake device (1) includes a support bracket (9), and a guiding assembly (15) and a braking assembly (17) mounted onto the support bracket (9).

Abstract: The invention relates to a system to control the motor drive of a garage door panel which is reciprocatingly movable and guided along a predetermined track between two end positions, and possibly, one or more intermediate stop positions, said garage door panel including a switching device which indicates the assumption of the respective end position or stop positions, the output signals of this switching device being usable to switch off the power supply to the drive motor, wherein the limit switches or reference point switches are actuatable through rotatable cams which simulate the garage door path. According to the invention, both the rotating cams as well as the limit switches are combined to form one constructional unit.

Abstract: A system for raising and lowering a sectional overhead door between an open position and a closed position including, a counterbalance system adapted to be connected to the door, an operator motor assembly mounted proximate to the sectional overhead door in the closed position of the sectional overhead door, at least a portion of the operator motor assembly movable between a door operating position and a door locking position, and a locking assembly (370) having an engaged position to hold the motor assembly in the operating position and a disengaged position to release the motor assembly allowing it to move to the door locking position. The system may be provided with a remote light assembly having a switchable light source in sensing communication with the operator motor such that operation of the motor activates the light source.

Abstract: An overhead garage door with a counterbalance mechanism incorporated into a pocket or hollow section formed in the door.

Abstract: A shaft operator assembly for moving a door assembly which includes a movable door leaf and a door shaft attached to the door leaf for common movement together. A shaft connecting unit includes a shaft connecting element and a connecting plate element and connects a driven member of the shaft operator assembly with minimal space requirements to the door shaft. The connecting plate element, which can be secured to or integrally configured with the driven member, is relatively thin to permit the jack shaft operator and connecting plate element to be shifted into a fitted position even where little space is available. The shaft connecting element is mountable non-rotatably on the door shaft and includes an axial opening extending through the shaft connecting element for receiving the door shaft.

Abstract: An arrangement of cooling tubes within a Fischer-Tropsch slurry reactor simplifies removal and reinstallation of cooling tubes for reactor maintenance.

Abstract: A universal overhead door system includes a pair of horizontal track members, a pair of vertical track members and a pair of track radius members interconnecting the horizontal and vertical track members. A pair of adjustable short radius members extend from the track radius members to guide uppermost rollers of an overhead sectional door. The overhead door system includes a pair of stationary sheaves positioned outboard of a pair of horizontal support rails which support the horizontal track members. A detent is provided at one end of the adjustable radius members to prevent undesirable travel the garage door. A spacer is provided for use in extension spring configurations when a long horizontal support rail is required. The spacer prevents metal-to-metal contact of moveable sheaves with the horizontal support rails.

Abstract: A balance control system comprises a motor, a transmission system providing connection between the motor and the door and adapted to move the door between a closed position and an open position located above the closed position, a counterbalance system to reduce power required to lift the door, an apparatus to generate first signal representing a force used to move the door from the closed position to the open position, and to generate a second signal representing a force used to move the door from the open position to the closed position, and a controller responsive to the first signal and to the second signal to indicate an imbalance of the door when a difference between the first signal and the second signal exceeds a predetermined threshold.

Abstract: A mechanism and method for operating a track-mounted door is disclosed. The mechanism includes a pair of side drums that are connected by first cables to the bottom of the door. The side drums are coaxially mounted on a shaft for simultaneous rotation with a pair of cable drums. The cable drums are connected to high pressure gas struts by second cables. Each second cable is carried around a shiv wheel that slides along a guide track as the second cable moves. Each shiv wheel is operatively connected to one of the gas struts. As the shiv wheel moves along the guide track toward the cable drum, the gas strut is charged. As the shiv wheel moves away from the cable drum, the gas strut is discharged. A standard electric motor and screw driven lift-arm is used to initiate the opening and closing of the door. The charged gas strut stores sufficient energy to overcome friction and gravity to assist the electric motor and lift-arm to open the door.

Abstract: A winding system for winding a rolling door assembly. The winding system includes a support bracket, first and second gears. The support bracket is preferably rigidly connectable to a fixed structure of the rolling door assembly, and has a receiving device and a supporting device. The first gear is pivotally mounted about the receiving device of the support bracket and rotatable thereabout along opposite first and second directions of rotation. The second gear is pivotally mounted about the supporting device of the support bracket and rotatable thereabout along opposite first and second directions of rotation. The first gear is operatively connected to a corresponding end of the counterbalancing spring of the rolling door assembly.

Abstract: A cable tensioner for an industrial door helps keep a cable neatly wrapped on its take-up drum. In some embodiments, the tensioner functions in a first mode during normal door operation, and operates in a second mode when the tension in the cable decreases to a predetermined low level. When operating in the second mode, the tensioner is able to take up slack in a cable that supports a door member, such as a door panel or a deadweight that counteracts the door panel's weight. The tensioner includes a shock absorber that resists a reaction force pulling on the tensioner when the tensioner is in the second mode. The tensioner may be adapted for use on various doors including, but not limited to, sectional doors, roll-up doors, high-lift doors, horizontally storing doors, vertically storing doors, and various combinations thereof.

Abstract: A drive system is provided for a moveable barrier, such as a garage door, that limits unauthorized shifting thereof. The drive system includes a flexible actuator for raising and lowering the door. The flexible actuator is tensioned with a biasing mechanism to minimize actuator throw, and a stop assembly of the biasing mechanism limits unauthorized travel of the garage door from the closed position by a predetermined amount that is sufficiently small so as to keep intruders out of the garage. The flexible actuator may for example, be a cable, a belt or a chain.

Abstract: A drop-catch mechanism for preventing the door leaf of an overhead door from rapidly closing upon breakage of the balancing spring thereof. The drop-catch mechanism having an input member for coupling with the balancing spring of the overhead door, a ratchet wheel for coupling with a winding axle carrying the door leaf of the overhead door, a pawl, and a positive mechanical drive for moving the pawl from a free position that allows rotation of the ratchet wheel to a catching position that blocks rotation of the ratchet wheel, the positive mechanical drive being configured such that, in use, breakage of the balancing spring coupled to the input member causes the pawl to move from the free position to the catching position.

Abstract: A plug for operatively connecting a torsion spring onto a corresponding component of a counterbalancing mechanism of a door assembly. The plug includes a connecting portion for removably connecting the plug onto the corresponding component, a substantially cylindrical collar insertable into an end portion of the torsion spring, an anchoring portion disposed on a bottom section of the collar for cooperating with a coil of the end portion of the torsion spring so as to pivotally anchor the collar onto the end portion of the torsion spring, and a clip projecting from a top section of the collar, and being disposed at a location on the collar substantially diametrically opposite from where the anchoring portion is disposed on the bottom section of the collar.

Abstract: Hardware that improves safety and minimizes the risk involved in installing, maintaining, and operating sectional doors that use springs to facilitate door movement. A lock-on side bearing bracket bears up a spring on a garage door. This side-bearing bracket includes a hook and a perpendicular tab to prevent the spring from dangerously releasing its energy when parts supporting the spring are removed or fail. A lock-on bottom roller bracket having a bottom bearing plate and a safety hook similarly prevents a potential release of energy when the garage door lift cable is tensed. A curled portion at the bottom of the lift cable prevents the cable from coming off the drum. A safety latch with a latch bar and a latch cover acts as a lock for the garage door.

Abstract: A ratcheting system is used to wind a helical torsion spring around a torsion bar in a counterbalancing mechanism for an overhead door having multiple panel sections. The ratcheting system contains: (1) a cylindrical sleeve encompassing the torsion bar, the sleeve having longitudinal channels and being secured to the torsion bar at the winding end of the torsion spring; (2) a winding cone adapted to fit over the cylindrical sleeve and having a cone-shaped section connected to the winding end of the torsion spring, a plurality of radial openings for receiving winding bars, a first threaded radial opening containing a set screw, and a second threaded radial opening containing a pull pin, the pull pin having a spring-biased beveled projection that extends inwardly from the winding cone to contact the longitudinal channels of the cylindrical sleeve.

Abstract: A plug for use in a counterbalancing mechanism of a cable-operated door. The plug is used for operatively connecting an overhead shaft to a torsion spring co-axially mounted thereon. The plug includes a cylindrical collar and a cylindrical flange. The cylindrical collar has opposite first and second portions and is provided with a hooking slot for hooking a free end of the torsion spring thereon, and the torsion spring having a segment coaxially mounted about the first portion of the collar. The cylindrical flange is rigidly affixed to the second portion of the collar and is used for transferring a torque between the torsion spring and the overhead shaft when the flange is securely fixed about the overhead shaft.

Abstract: A guide device for winding shaft (4) of a material handling door (1) includes vertical members (2, 3) including in their upper part a bore (11) traversed by the actuator (13) of the shaft (4) such that each bearing (14, 15) cop-operates with a plate (16) fixed on the profile of the vertical members to guide the shaft (4) in rotation, while the bore (11) includes a device for braking the actuator (13) when a bearing (14, 15) and/or the corresponding plate (16) is broken thereby preventing the shaft (4) from falling vertically and for lowering the flexible curtain.

Abstract: A counter weight door has a plurality of counter weights each associated with a respective one of the panels and an interconnecting spring connecting each of the weights to the next. At least one of the counter weights has a cradle which is arranged to receive a plurality of weighted members. The spring arrangement connecting one counter to the next is housed within the cradle and includes a shaft on which the spring is mounted. The door has a pulley system which has a first pulley on one side of the door, a second double pulley on the other side of the door, a first cable fixed at a first end to the door extending through the first pulley and a second cable fixed at a first end to the door extending through the second pulley to the counter weight system.

Abstract: An arrangement for monitoring a condition of a counterbalance torsion spring in an overhead door or gate and preventing the door or gate from accidentally slamming shut or dropping too rapidly when the spring fails. The arrangement includes a drum mounted on a shaft which transmits the torque of the spring to the drum. During normal operation a sensor and release assembly maintains a catcher in a inactive position and when the spring fails, the sensor and release assembly allows the catcher to move to an active position and engage a grabber disposed on an inside surface of the drum to block rotation of the drum and therefore movement of the door or gate.

Abstract: There is provided a new and useful garage door (12) opening/closing system (10) comprising a garage door (12) having top (32), bottom (34), and first and second sides (54, 56) and having a series of rollers (58) associated with the first and second sides (54, 56); a pair of door rails (14, 16) at the first and second sides (54, 56) of the door (12) for receiving the rollers (58) for movement of the door along the rails (14, 16), in a door opening path; at least one hinge part mounted on the door intermediate the first and second ends (54, 56); a central guide rail (18) extending outwardly from the plane of a closed position of the door (12) from a position above the top (32) of the door (12); a trolley (20) mounted on the central guide rail (18) for movement along the guide rail, the trolley (20) for operative connection to at least one hinge part; at least one cable drum (22) having a pair of cables (26, 28) thereon operatively associated with the trolley for moving the trolley (20) along the central guide r

Abstract: An upwardly acting sectional door system including, a door (D) having a plurality of hinged door sections (16-18) movable between a closed vertical position and an open horizontal position, a drive tube (31) mounted above the door in the closed vertical position, an operator (11) selectively directionally rotatably driving the drive tube, cable drums (35) mounted on the drive tube for rotation therewith by the operator, springs (60) mounted in operative relation to the cable drums, and counterbalance cables (75) reeved about the cable drums and interconnecting the springs and the door to counterbalance the door when moving between the closed vertical position and the open horizontal position.

Abstract: A counteraction system for a sectional door includes a counterweight system that helps counterbalance the weight of the door and helps hold the door in place when the door is fully open. The counterweight system comprises a suspended string of individual deadweights. As the door opens, the weights sequentially lower onto the floor, in a stacked arrangement, one atop the other. Thus, the hanging weight of the counterweight system decreases as the door opens. To avoid having the counterweight system slam the door open against a hard stop, the counteraction system also includes a brake system that helps bring the door to a smooth stop at the door's fully open position. In some embodiments, the brake system includes a cable that traverses the direction that the door travels. As the door approaches its open position, a protrusion on the door catches the cable, which deflects to decelerate the door.

Abstract: Guide track assemblies for upward acting doors include substantially linear vertical and horizontal track sections and curvilinear transition sections formed as portions of each of the vertical and horizontal linear sections. The track assemblies are supported, respectively, by mounting brackets which also support a counterbalance mechanism for the door. The curvilinear transition track sections are formed integral with the vertical and horizontal track sections and may have a constant or elliptical radius of curvature, the latter to provide clearance for the guide track assemblies in low headroom installations. The mounting brackets are formed of stamped metal plates which are folded to provide a first flange for attaching the mounting bracket to a structural wall, a support part including a flag portion for connection to the guide track sections and a second flange for connection to a door counterbalance mechanism.

Abstract: A door system including a door movable between a closed vertical position and an open horizontal position, a cable interconnected to said door near the bottom thereof, the cable extending along a vertical line adjacent the door and being normally, substantially taut, and an anti-drop assembly having a pawl pivotally supported on the door, a stop surface formed adjacent the door and a spring operable to urge the pawl toward engagement with the stop surface, wherein the pawl is oriented such that it rotates in a plane passing through the cable and placed in contact therewith such that the taut cable opposes the biasing force of the spring, whereby upon the cable going slack, the spring biases the pawl into engagement with the stop surface to decelerate the door.

Abstract: A plug for use in a counterbalancing mechanism of a cable-operated door. The plug is mounted about an overhead shaft and used for operatively connecting the overhead shaft to a torsion spring coaxially mounted thereon. The plug includes a cylindrical collar and a cylindrical flange. The cylindrical collar has opposite first and second portions. The collar is provided with a hooking slot for hooking a free end of the torsion spring therein and the torsion spring has a segment coaxially mounted about the first portion of the collar. The cylindrical flange is rigidly affixed to the second portion of the collar. The flange is used for transferring a torque between the torsion spring and the overhead shaft when the flange is securely fixed about the overhead shaft. The plug further includes a shouldering floor of a given length faced against the hooking slot and extending inside the collar, from the second portion towards the first portion thereof, between the collar and the overhead shaft.

Abstract: A counteraction system for a sectional door includes a counterweight system that helps counterbalance the weight of the door and helps hold the door in place when the door is fully open. The counterweight system comprises a suspended string of individual deadweights. As the door opens, the weights sequentially lower onto the floor, in a stacked arrangement, one atop the other. Thus, the hanging weight of the counterweight system decreases as the door opens. To avoid having the counterweight system slam the door open against a hard stop, the counteraction system also includes a brake system that helps bring the door to a smooth stop at the door's fully open position. In some embodiments, the brake system includes a cable that traverses the direction that the door travels. As the door approaches its open position, a protrusion on the door catches the cable, which deflects to decelerate the door.

Abstract: A counterbalance system (10) for an upwardly acting door (D) movable on tracks (T, T) between a closed position and an open position having, a drive tube (31) adapted to be mounted above the door in the closed position, a cable drum assembly (30) mounted proximate each end of the drive tube, a cable connecting each cable drum assembly and the door, a cylindrical member (40) on the cable drum assembly, a cable receiving surface (42) on the cylindrical member extending laterally between the door and the tracks and receiving multiple layers (F, S) of the cable during movement of the door from the closed position to the open position, whereby the cable avoids engagement with the door during movement between the closed position and the open position.

Abstract: A method and apparatus for counterbalancing a roll-up door uses a conventional coil spring having adjacent coils engaging each other. The spring is elongated to provide for spring growth during the winding of the spring. A worm gear box operates to wind the elongated spring and retain the spring in the wound position to continuously apply torsion force to a shaft operatively connected to the door the counterbalance the door.

Abstract: A drop-catch mechanism for preventing a door leaf of an overhead door from falling down upon breakage of a balancing spring thereof, the mechanism comprising an input member for coupling with a balancing spring of the overhead door, a ratchet wheel for coupling with a winding axle carrying the door leaf of the overhead door, a pawl, and means for moving the pawl from a free position that allows rotation of the ratchet wheel to a catching position that blocks rotation of the ratchet wheel, the means for moving the pawl being configured such that, in use, breakage of a balancing spring coupled to the input member causes the pawl to move from the free position to the catching position, characterized in that the means for moving the pawl from the free position into the catching position comprise a positive mechanical drive extending from the input member to the pawl.

Abstract: A counterbalance system for an upward-acting door includes spaced-apart wall brackets and cable drums supported on the brackets and connected to flexible cables which depend from the drums and connected to the lower side edges of an upward-acting sectional garage door. One or both of the cable drums may be connected to one end of a torsion coil spring and the opposite end of each spring is connected to a hub assembly. Elongated spring winding and protective cover tubes are sleeved over the springs and are connected to the brackets by worm-gear drive winding mechanisms, respectively, for rotating the tubes to effect winding of the torsion coil springs through the hub assemblies but preventing rotation of the tubes during normal operation of the counterbalance system. The cable drums and spring hub assemblies may be supported on an elongated synchronizing shaft or a torque transfer shaft extending between and supported on the wall brackets.