Technical field

The present invention relates to a garage door and a lift mechanism for a garage door. It specifically relates to a torsion spring system, having a plurality of torsion springs, for a garage door.

Background of the invention

Garage doors are usually heavy. Therefore, some garage doors are made in several jointed panels that roll up on tracks across the garage ceiling, or into a roll above the doorway. The operating mechanism for these doors is normally spring-loaded or counterbalanced to offset the weight of the door and reduce human or motor effort required to operate the door. One common operating mechanism for

counterbalancing is a torsion spring lift mechanism, which consists of two tightly wound up springs on a steel shaft with cable drums at both ends. The entire apparatus mounts on the header wall above the garage door and have three supports: a center bearing plate with a steel or nylon bearing and two end bearing plates at both ends. The springs themselves each consist of a steel wire with a stationary cone at one end and a winding cone at the other end. The stationary cone may be attached to the center bearing plate. Steel counterbalance cables run from the roller brackets at the bottom corners of the door to a notch in the cable drums. When the door is raised, the springs unwind and the stored tension lifts the door by turning the shaft, thus turning the cable drums, wrapping the cables around the grooves on the cable drums. When the door is lowered, the cables unwrap from the drums and the springs are rewound to full tension.

A torsion spring lift mechanism may need spring break devices. This is due to the fact that the force applied by a tensioned torsion spring may be large. Normally two spring break devices per door are used. However, the use of spring break devices makes the mechanism more expensive and more complicated. Therefore, there may be a need for a torsion spring lift mechanism with fewer or without spring break devices. Furthermore, at installation, the springs need to be winded up for proper counterbalancing and then secured to the shaft. One winding cone for each of the springs may be used for securing the springs to the shaft. Once the springs are secured to the shaft, it may be difficult or cumbersome to readjust the counterbalance mechanism, especially without proper tools. Thus, there may be a need for a torsion spring lift mechanism, which is easy to readjust after installation. Furthermore, there may be a need for a torsion spring lift mechanism, which may be readjusted after installation without tools.

Summary of the invention

An object of the present disclosure is to provide a torsion spring system for assisting in operating a garage door, which seeks to mitigate, alleviate, or eliminate one or more of the above-identified deficiencies/disadvantages in the prior art and/or other deficiencies/disadvantages singly or in any combination.

An object of the present disclosure is to provide a torsion spring system, which can be easily adjusted and/or easily readjusted.

An object of the present disclosure is to provide a torsion spring system, for which spring tension can be adjusted with less force.

An object of the present disclosure is to provide an alternative way of readjusting the spring tension. An object of the present disclosure is to enable faster readjustment of the spring tension.

An object of the present disclosure is to enable easier readjustment of the spring tension.

An object of the present disclosure is to enable readjustment by hand of the spring tension.

An object of the present disclosure is to enable readjustments of the spring tension without the use of tools or without the use of specially adapted tools.

An object of the present disclosure is to enable more precise adjustments or readjustments of the spring tension. An object of the present disclosure is to provide means for attaching torsion springs together.

An object of the present disclosure is to provide means for attaching, fixing or locking a winding plug to a shaft and/or means for attaching torsion springs to a shaft. An object of the present disclosure is to provide torsion springs, which will not expand/contract when the tension is adjusted, thereby enabling that the torsion springs can extend from the first support bearing plate to the second support bearing plate at all times.

An object of the present disclosure is to provide a torsion spring, having a length, which does not change with tensioning or winding.

An object of the present disclosure is to provide a torsion spring, which has the same length during all operating conditions.

An object of the present disclosure is to provide a sliding coupling between a shaft and support bearing plates/end brackets. An object of the present disclosure is to provide a torsion spring lift mechanism with fewer or without spring break devices.

An object of the present disclosure is to provide a torsion spring lift mechanism with fewer components.

An object of the present disclosure is to provide a less complicated torsion spring lift mechanism.

An object of the present disclosure is to increase the life expectancy of the torsion spring system.

An object of the present disclosure is to enable fixation of torsion springs between two bearing plates. An object of the present disclosure is to enable tightening of torsion springs with the least amount of effort.

In this disclosure, a solution to the problem outlined above is proposed. In the proposed solution, a torsion spring system for assisting in operating a garage door is disclosed. The system comprises: an elongated shaft configured to be connected to the garage door; a winding plug, releasably attached to the shaft; first and second torsion springs; the first torsion spring having a first and a second end, the second torsion spring having a first and a second end, wherein the second end of the first torsion spring is connected to the winding plug and the first end of the second torsion spring is connected to the winding plug; first and second support bearing plates, adapted to be mounted to a wall or a ceiling of a garage, for securing the system to the wall or the ceiling; a first bayonet plug connected to the first end of the first torsion spring and releasably connected to the first support bearing plate; and a second bayonet plug connected to the second end of the second torsion spring and releasably connected to the second support bearing plate.

According to an aspect, the first and/or the second bayonet plugs comprises a male part of a bayonet coupling, the male part preferably being provided with two pins, and the first and/or the second support bearing plates comprises a female part of the bayonet coupling, the female part preferably being provided with two holes for receiving the pins.

According to an aspect, the winding plug comprises a first threaded part, preferably comprising a left-handed thread and second threaded part, preferably comprising a right-handed thread, the first threaded part being configured for engaging with the first torsion spring and the second threaded part being configured for engaging with the second torsion spring.

According to an aspect, the winding plug comprises a first hole for receiving a first rod and a second hole for receiving a second rod for tightening the first and second torsion springs by moving the winding plug clockwise or anti-clockwise.

According to an aspect, the winding plug comprises 4 or 6 equal faces.

According to an aspect, the winding plug is provided with a set mechanism for releasably attaching the winding plug to the shaft, the set mechanism being lockable into positions at every quarter turn of the winding plug.

According to an aspect, the winding plug is configured for connecting the second end of the first torsion spring to the elongated shaft and connecting the first end of the second torsion spring to the elongated shaft.

According to an aspect, the winding plug is configured for tensioning the first and second torsion springs to a desired torque by turning the winding plug. According to an aspect, the winding plug is configured for tensioning the first and second torsion springs to a desired torque by turning the winding plug an amount of quarter turns. According to an aspect, the winding plug is configured for releasably attaching the winding plug to the shaft by means of the set mechanism.

According to an aspect, the first and/or the second torsion springs are provided with space in-between windings.

According to an aspect, the length of the space in-between windings is such that the lengths of the first and second torsion springs are independent of if there is no tension or tension up to a maximum allowed tension applied to the first and/or the second torsion springs. By having such a distance of the space in-between windings it possible to tighten the springs with a low amount of effort.

According to an aspect, the first and/or the second support bearing plates are each connected to the shaft via a bearing.

According to an aspect, the first and/or the second support bearing plates each comprise an opening, wherein each opening is configured to receive a bearing. According to an aspect, each bearing is fitted onto the elongated shaft. According to an aspect, each bearing surrounding an axial part of the elongated shaft. According to an aspect, the first and/or the second support bearing plate is provided with an opening, each opening is configured to receive a bearing, each bearing is fitted onto the shaft, each bearing surrounding an axial part of the shaft.

According to an aspect, the first torsion spring radially encloses a first part of the shaft and the second torsion spring radially encloses a second part of the shaft.

According to an aspect, the winding plug radially encloses a third part of the shaft.

According to an aspect, the torsion spring system further comprises at least one winding drum.

According to an aspect, the winding drum is mounted onto the shaft.

According to an aspect, the winding drum is radially enclosing a fourth part of the shaft.

According to an aspect, the torsion spring system further comprises a lintel profile, and the lintel profile is attachable or attached to a wall or a ceiling.

According to an aspect, the first and second support bearing plates are configured to be mounted at predetermined positions of the lintel profile.

In this disclosure, a further solution to the problem outlined above is proposed. In the (further) proposed solution, a method of installing a torsion spring system for a garage door is disclosed. The method comprises: assembling a first torsion spring, a winding plug and a second torsion spring on an elongated shaft; the first torsion spring having a first and a second end, the second torsion spring having a first and a second end; connecting the second end of the first torsion spring to the winding plug and connecting the first end of the second torsion spring to the winding plug;

optionally providing a first and a second support bearing plate with a first and a second bearing; fitting the shaft through a central hole of the first bearing and through a central hole of the second bearing; optionally attaching a lintel profile to a wall or a ceiling; mounting the first and second support bearing plates at predetermined positions of the lintel profile or directly onto a wall; mounting a winding drum onto the shaft; engaging a male part of a first bayonet coupling, the male part preferably being provided with two pins, of a first bayonet plug connected to the first end of the first torsion spring with a female part of the first bayonet coupling, the female part preferably being provided with two holes for receiving the pins, of the first support bearing plate; engaging a male part of a second bayonet coupling, the male part preferably being provided with two pins, of a second bayonet plug connected to the second end of the second torsion spring, with a female part of the second bayonet coupling, the female part preferably being provided with two holes for receiving the pins, of the second support bearing plate; tensioning the first and second torsion springs by turning the winding plug an amount of quarter turns until a desired torque is achieved; and releasably attaching the winding plug to the shaft by adjusting a set mechanism of the winding plug.

In this disclosure, another solution to the problem outlined above is proposed. The solution is a method of readjusting the torsion spring system, the method comprising turning one of the bayonet plugs so that the pins of the bayonet plugs are released from the holes of the support bearing plate; turning the bayonet plug a desired amount of half turns; and reattaching the bayonet coupling by reinserting the pins of the bayonet plug into the holes of the support bearing plate.

In some embodiments, solutions or aspects, any of the above

aspects/solutions may additionally have features identical with or corresponding to any of the various features as explained above for any of the other aspects or solutions.

Brief description of the drawings The foregoing will be apparent from the following more particular description of the example embodiments and aspects, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the example embodiments and aspects.

Figure 1 discloses a schematic view of a torsion spring system according to an aspect of the invention.

Figure 2 is a flowchart illustrating example method steps according to an aspect of the invention.

Figure 3 discloses a schematic view of a support bearing plate engageable with a bayonet plug attached to a torsion spring via a bayonet coupling, according to an aspect of the invention.

Figure 4 is a flowchart illustrating example method steps according to an aspect of the invention.

Detailed description

Aspects of the present disclosure will be described more fully hereinafter with reference to the accompanying figures. The assembly disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein.

The terminology used herein is for the purpose of describing particular aspects of the disclosure only, and is not intended to limit the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Embodiments and aspects of the present disclosure will be described and exemplified more fully hereinafter with reference to the accompanying drawings. The solutions disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the embodiments and aspects set forth herein.

Below, reference is made to the term“releasably attach”. This term is to be understood as“releasably fix”,“releasably secure” or“releasably lock”, i.e. an attachment, fixation, securement or lock, which can easily be released or unlocked non-destructively.

Moreover, below the term“assisting in operating a garage door” is used.

Operating a garage door may comprise opening and/or closing the garage door.

Furthermore, below, reference is made to the term“support bearing plates”. Another term for“support bearing plate” is end bracket.

The present invention relates to a garage door and a lift mechanism for a garage door or for assisting in operating a garage door 198, shown in figure 1 . The garage door 198 may be heavy. Therefore, the garage door 198 is made in several jointed panels that roll up on tracks across the garage ceiling, or into a roll above the doorway. However, such garage doors are difficult to slide/roll up by hand. The garage door 198 is therefore provided with/comprises an operating mechanism, which is spring-loaded or counterbalanced to offset the weight of the garage door 198 and reduce human or motor effort required to operate the garage door 198. The operating mechanism for counterbalancing is a torsion spring lift mechanism or a torsion spring system.

More specifically, the present invention relates to a torsion spring system, having a plurality of torsion springs, for a garage door or for assisting in operating a garage door. The present invention also relates to a method of installing a torsion spring system for a garage door or for assisting in operating a garage door.

Figure 1 discloses a schematic view of a torsion spring system 100 for assisting in operating a garage door 198. The torsion spring system 100 comprises an elongated shaft 1 10. Furthermore, the torsion spring system 100 comprises a winding plug 120. In an aspect, the torsion spring system 100 comprises only one winding plug 120. The winding plug 120 is releasably attached to the shaft 1 10. The winding plug 120 is provided with a set mechanism for releasably attaching the winding plug 120 to the shaft 1 10. The set mechanism is lockable or settable into positions at every quarter turn of the winding plug 120. Thus, a means for fixing, locking, securing or attaching the winding plug 120 to the shaft 1 10 is provided. The set mechanism may be a single screw, two screws, a plurality of screws, a pin, two pins, a plurality of pins, a hook, two hooks, a plurality of hooks or any other suitable fastener. Moreover, the torsion spring system 100 comprises a first torsion spring 130 and a second torsion spring 140. The first torsion spring 130 has a first end 132 and a second end 134. The second torsion spring 140 has a first end 142 and a second end 144. The second end 134 of the first torsion spring 130 is connectable or connected to the winding plug 120. The first end 142 of the second torsion spring 140 is connectable or connected to the winding plug 120. Thus, the first torsion spring 130 is connected with the second torsion spring 140 via the winding plug 120. In an aspect, the winding plug 120 comprises a first threaded part. The first threaded part preferably comprises a left-handed thread. Furthermore, in an aspect, the winding plug 120 comprises a second threaded part. The second threaded part preferably comprises a right-handed thread. The first threaded part is configured for engaging with the first torsion spring 139. The second threaded part is configured for engaging with the second torsion spring 139. The first torsion spring 139 is wound onto the first threaded part of the winding plug 120 and fixed to the winding plug 120 by means of friction, by bending a part of the first torsion spring 139 or by use of a fixation bolt or a fixation clip. The second torsion spring 139 is wound onto the second threaded part of the winding plug 120 and fixed to the winding plug 120 by means of friction, by bending a part of the second torsion spring 139 or by use of a fixation bolt or a fixation clip. Alternatively, each of the first and second threaded parts are configured for engaging with a correspondingly threaded nut, each of the correspondingly threaded nuts being attached, preferably fixedly attached, to one of the first and the second torsion springs 130, 140. Thus, the first and the second threaded parts together with the corresponding nuts provide a means for attaching the torsion springs 130, 140 to the shaft 1 10 via the winding plug 120.

The elongated shaft 1 10 is configured to be connected to the garage door 198. The elongated shaft 1 10 is configured to transfer forces from the springs to the garage door 198 to assist in opening the garage door 198. The elongated shaft 1 10 is configured to transfer forces from the garage door 198 when it is closed to tension the springs.

In an aspect, the winding plug 120 is configured for connecting the second end 134 of the first torsion spring 130 to the winding plug 120 and connecting the first end 142 of the second torsion spring 140 to the winding plug 120. In an aspect, the winding plug 120 is configured for connecting the second end 134 of the first torsion spring 130 to the elongated shaft 1 10 and connecting the first end 142 of the second torsion spring 140 to the elongated shaft 1 10.

In an aspect, the winding plug 120 is configured for tensioning the first and second torsion springs 130, 140 to a desired torque by turning the winding plug 120 an amount of quarter turns, i.e. the winding plug 120 is configured for tensioning both of the first and second torsion springs 130, 140 to a desired torque simultaneously, and releasably attaching the winding plug 120 to the shaft 1 10 by means of the set mechanism.

The torsion spring system 100 comprises a first support bearing plate 150 and a second support bearing plate 160. The bearing plates 150, 160 are adapted to be mounted to a wall or a ceiling of a garage. When the bearing plates 150, 160 are mounted to the wall or the ceiling, the torsion spring system 100 is secured to the wall/ceiling. According to an aspect of the invention, a lintel profile 190 is attached to a wall or a ceiling of a garage. The bearing plates 150, 160 are mounted at predetermined positions of the lintel profile 190. At predetermined positions there may be a marking, a slot or a hole. The mounting may be performed utilizing screws, bolts and nuts or any other suitable fastening means. Furthermore, the torsion spring system 100 comprises a first bayonet plug 170. The first bayonet plug 170 is connected, attached, secured or fixed to the first end 132 of the first torsion spring 130. The first bayonet plug 170 is releasably connected to the first support bearing plate 150. Moreover, the torsion spring system 100 comprises a second bayonet plug 180. The second bayonet plug 180 is connected, attached, secured or fixed to the second end 144 of the second torsion spring 140. The second bayonet plug 180 is releasably connected to the second support bearing plate 160. Since, the torsion spring system 100 is provided with a winding plug 120 and first and second bayonet plugs 170, 180, the torsion spring system 100 can easily be adjusted, the spring tension can be adjusted with less force and/or the spring tension can be readjusted by hand (without use of tools). The torsion spring system is according to an aspect arranged so that the first torsion spring 130 radially encloses a first part or length of the shaft 1 10 and the second torsion spring 140 radially encloses a second part or length of the shaft 1 10. The first and the second torsion springs 130, 140 are elongated and coil shaped with windings around an axis. The first and the second torsion springs 130, 140 each have an axial through hole. The first and second parts of the shaft 1 10 are arranged inside the through holes of the first and second torsion springs 130, 140. Furthermore, according to an aspect, the winding plug 120 is provided with a centrally located, axial through hole and radially encloses a third part or length of the shaft 1 10. Thus, the third part of the shaft 1 10 is arranged inside the through hole of the winding plug 120. Moreover, according to an aspect, the torsion spring system further comprises one, two or a plurality of winding drums 195, mounted onto the shaft 1 10, and radially enclosing a fourth part of the shaft 1 10.

In an aspect, the first and/or the second torsion springs 130, 140 are provided with space in-between windings. By having space in-between the windings, the torsion springs 130, 140 will not expand or contract. The space in-between the windings enables the torsion springs 130, 140 to extend from the first support bearing plate to the second support bearing plate at all times, without expanding or contracting in length, regardless of the tension applied to the torsion springs 130, 140, i.e. the length of the torsion springs 130, 140 is constant, at least within the operating range of tension. Thus, after tensioning/winding of the torsion springs 130, 140, the torsion springs 130, 140 still have the same length. The lengths of the torsion springs 130, 140 do not change, i.e. the lengths of the torsion springs 130, 140 are independent of the tensioning/winding of the torsion springs 130, 140. Thus, the lengths of the torsion springs 130, 140 are dictated by the fixation points of the torsion springs 130, 140. When the torsion springs 130, 140 are tensioned, instead of expanding, the amount of windings of the torsion springs 130, 140 is increased.

In an aspect, the length of the space in-between windings is such that the lengths of the first and second torsion springs 130, 140 are independent of if there is no tension or tension up to a maximum allowed tension applied to the first and/or the second torsion springs 130, 140. Since the torsion springs 130, 140 extend from the first support bearing plate 150 to the second support bearing plate 160 at all times after installation, the torsion springs 130, 140 may be longer and have more windings than a shorter torsion spring, and can therefore be made of a thin wire or a wire with a small diameter or a wire with a smaller diameter than a regular torsion spring. Furthermore, the force applied per turn/revolution (of the torsion spring) by a tensioned torsion spring 130, 140 may be low or lower than the force applied per turn/revolution by a regular torsion spring. As the force applied per turn/revolution may be lower, fewer or no break devices may be needed for the torsion spring system 100.

In an aspect, the torsion springs 130, 140 are helical springs or cylindrical coil springs, made of wire of a spring steel. The wire has a round shape and a wire diameter. The wire diameter is anywhere from 0.003 meters, m, to 0.03 m, such as 0.004m, 0.008m, 0.01 m or 0.021 m.

In an aspect, the amount of space in-between the windings is sufficient for providing space for any additional winding due to tensioning. The space in-between the windings is in an aspect equal to the wire diameter. In another aspect, the space in-between the windings is half the wire diameter. In another aspect, the space in- between the windings is twice the diameter of the wire. In yet another aspect, the space in-between the windings is four times the diameter of the wire. The space in-between the windings may be anywhere from half the wire diameter to four times the diameter of the wire.

Figure 2 is a flowchart illustrating example method steps according to an aspect of the invention. The steps relate to a method 200 of installing a torsion spring system 100 for a garage door 198. The method 200 comprises installing the torsion spring system 100, i.e. putting all the parts together and up on the wall; tensioning the first and second torsion springs 130, 140 until a desired torque is achieved; and releasably attaching the first and second torsion springs 130, 140 to the shaft 1 10 via the winding plug 120. More specifically, the method 200 comprises assembling 210 a first torsion spring 130, a winding plug 120 and a second torsion spring 140 on, such as onto and surrounding, an elongated shaft 1 10. The first torsion spring 130 has a first end 132 and a second end 134. The second torsion spring 140 has a first end 142 and a second end 144. The method 200 comprises connecting 214 the second end 134 of the first torsion spring 130 to the winding plug 120 and connecting 216 the first end 142 of the second torsion spring 140 to the winding plug 120. Furthermore, the method 200 optionally comprises providing 220 a first support bearing plate 150 with a first bearing 155 and providing 220 a second support bearing plate 160 with a second bearing 165.

With the use of the bearings 155, 165, the life expectancy of the torsion spring system 100 may be increased. Moreover, the method 200 comprises fitting 230 the shaft 1 10 through a central hole of the first bearing 155 and fitting 230 the shaft 1 10 through a central hole of the second bearing 165. The method 200 optionally comprises attaching 240 a lintel profile 190 to a wall or a ceiling, preferably a wall or a ceiling of a garage and mounting 250 the first and second support bearing plates 150, 160 at predetermined positions of the lintel profile 190. Alternatively, the method 200 comprises mounting the first and second support bearing plates 150, 160 directly onto the wall or ceiling. Furthermore, the method 200 comprises mounting 260 one or two winding drums 195 onto the shaft 1 10. Moreover, the method 200 comprises engaging 270 a male part of a first bayonet coupling of a first bayonet plug 170 connected to the first end 132 of the first torsion spring 130 with a female part of the first bayonet coupling of the first support bearing plate 150. The male part of the first bayonet coupling is preferably provided with one or two pins, and the female part of the first bayonet coupling is preferably provided with one or two holes for receiving the pin or pins of the male part of the first bayonet coupling. However, alternatively, the male part of the bayonet coupling is part of the first support bearing plate 150 and the female part is part of a first bayonet plug 170 and connected to the first end 132 of the first torsion spring 130. The method 200 comprises engaging 280 a male part of a second bayonet coupling of a second bayonet plug 180 connected to the second end 144 of the second torsion spring 140 with a female part of the second bayonet coupling of the second support bearing plate 160. The male part of the second bayonet coupling is preferably provided with one or two pins, and the female part of the second bayonet coupling is preferably provided with one or two holes for receiving the pin or pins of the male part of the second bayonet coupling. Alternatively, the male part of the bayonet coupling is part of second support bearing plate 160 and the female part is part of a second bayonet plug 180 and connected to the second end 144 of the second torsion spring 140. Furthermore, the method 200 comprises tensioning the first and second torsion springs 130, 140 by turning the winding plug 120 until a desired torque is achieved, the desired torque resulting in a desired counterbalancing. According to an aspect the method 200 comprises tensioning the first and second torsion springs 130, 140 by turning the winding plug 120 an amount of quarter turns, or any other amount, such as a 1 /3 turn, until a desired torque is achieved. The turning of the winding plug 120 is performed with tools, such as wrenches. According to an aspect, the winding plug 120 comprises a plurality of holes for receiving at least one rod. A first rod is inserted into a first hole of the plurality of holes (and held in place), thereby maintaining the tension of the first and second torsion springs 130, 140. A second rod is subsequently inserted into a second hole of the plurality of holes for tightening the first and second torsion springs 130, 140 by moving the winding plug with the second rod clockwise or anti-clockwise. According to an aspect, the winding plug 120 comprises 6 equal faces, i.e. the winding plug is hexagonal (cross-sectionally). The tightening of the first and second torsion springs 130, 140 is then performed with regular spanners or wrenches by holding one spanner still and moving the winding plug 120 with the other spanner clockwise or anti-clockwise. According to an aspect, the winding plug 120 comprises 4 equal faces, i.e. the winding plug is square (cross-sectionally). The tightening of the first and second torsion springs 130, 140 is then performed with regular spanners or wrenches as described for the hexagonal case above. Moreover, the method 200 comprises releasably attaching 290 the winding plug 120 to the shaft 1 10 by adjusting a set mechanism of the winding plug 120.

Figure 3 illustrates a support bearing plate 150 engageable with a bayonet plug 170, attached to a torsion spring 130, via a bayonet coupling, according to an aspect of the invention. The bayonet plug 170 is attached to the torsion spring 130 by means of friction or by bending the wire of the torsion spring 130. Alternatively, the bayonet plug 170 is attached by means of a rivet, bolt or screw. As mentioned above in connection with fig. 1 , the torsion spring system 100 comprises an elongated shaft 1 10, a first torsion spring 130, a first support bearing plate 150, a first bearing 155 and a first bayonet plug 170. As can be seen in fig. 3, the elongated shaft 1 10 is provided with a ring-shaped bearing 155, which snugly surrounds the elongated shaft 1 10 for a part, such as an axial part, of the length of the elongated shaft 1 10. The first support bearing plate 150 is provided with an opening 156. The opening 156 is configured, such as shaped and/or sized, to receive a bearing 155, e.g. when the bearing is fitted onto the shaft 1 10 or prior to the bearing being fitted onto the shaft 1 10. The bearing 155 is ring-shaped and configured, such as shaped and/or sized, to fit into the opening 156. In an aspect, the bearing 155 comprises a rim 157. The rim 157 is preferably fixed between the bearing plate 150 and the bayonet plug 170. The first and/or the second support bearing plate 150, 160 are each connected to the shaft 1 10 via a bearing 155, 165.Thus, the bearing 155 provides a coupling of the shaft 1 10 to the support bearing plate 150, wherein the shaft 1 10 is moveable relative the support bearing plate 150 in an axial direction of the shaft 1 10.

The first bayonet plug 170 comprises a male part of a bayonet coupling. The male part is provided with one or more pins, preferably a first and a second pin 172, 174. The pins 172, 174 extend perpendicularly from a body 171 of the first bayonet plug 170. The pins 172, 174 may be any suitable shape, such as round, square or star-shaped. The pins 172, 174 may be angled, curved or L-shaped in a longitudinal direction so as to provide part of a locking mechanism. Alternatively or additionally, the male part may be provided with hooks or any other suitable objects. The first support bearing plate 150 comprises a wall attachment part 158. The wall attachment part 158 is provided with holes for attaching the first support bearing plate 150 with a wall of a garage or with a lintel 190 attached to a wall of a garage. The holes are suitable for receiving bolts, rivets or screws for attaching the first support bearing plate 150 to the wall or to the lintel 190. The first support bearing plate 150 comprises a female part 159 of the bayonet coupling. The female part 159 is perpendicular to the wall attachment part 158. The female part is provided with one or more holes, preferably a first and a second hole 152, 154, for receiving the one or more pins, and preferably the first and second pins 172, 174, of the male part of the bayonet coupling. The first pin 172 is configured to fit into any of the first and the second holes 152, 154. The second pin 174 is configured to fit into any of the first and the second holes 152, 154. Thus, the first torsion spring 130, which is releasably attached to the shaft 1 10 at the second end 134, shown in fig. 1 , can be turned any multiple of half a turn for adjusting or readjusting the tension of the torsion springs 130, 140. Although explained here as the bayonet plug 170 attached to the torsion spring 130 and engageable with the support bearing plate 150, the coupling between the bayonet plug 180 attached to the torsion spring 140 and engageable with the support bearing plate 160 is the same or corresponding. Thus, the tension can be adjusted or readjusted in two different ways and at three different positions, namely at the winding plug 120 or at either of the support bearing plates 150, 160. Thus, an alternative way of readjusting the spring tension is provided. Furthermore, faster and/or easier readjustment of the spring tension is enabled. Moreover, readjustment of the spring tension by hand, without the use of tools or without the use of specially adapted tools, is enabled.

Figure 4 is a flowchart illustrating example method steps according to an aspect of the invention. The steps relate to a method 292 of readjusting 292 the torsion spring system 100. The torsion spring system is described above. In an aspect, the method 200 is performed at installation or any time after installation. The readjusting 292 is performed in order to change the spring tension as needed. The readjusting 292 is performed by turning 294, preferably by hand, one of the bayonet plugs 170, 180, such as clockwise, so that the pin or pins of that bayonet plug 170, 180 are released from the hole or holes of the support bearing plate 150, 160, pulling, preferably by hand, the bayonet plug 170, 180 away from the support bearing plate 150, 160 far enough to be able to turn the bayonet plug 170, 180 without the pin or pins of the bayonet plug 170, 180 penetrating the hole or holes of the support bearing plate 150, 160, turning 296, preferably by hand, the bayonet plug 170, 180 a desired amount of half turns (or revolutions), such as a half turn, one turn, 1 ½ turn, 2 turns etc., in order to obtain a more suitable counterbalancing weight, gently pushing, preferably by hand, the pin or pins of the bayonet plug 170, 180 back towards the support bearing plate 150, 160, reattaching 298, preferably by hand, the bayonet coupling by reinserting, preferably by hand, the pin or pins of the bayonet plug 170, 180 into the hole or holes of the support bearing plate 150, 160 and optionally turning, preferably by hand, the bayonet plug 170, 180, such as anti-clockwise, to secure the bayonet plug 170, 180 to the support bearing plate 150, 160.

The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments and aspects described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

The description of the aspects of the disclosure provided herein has been presented for purposes of illustration. The description is not intended to be

exhaustive or to limit aspects of the disclosure to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of various alternatives to the provided aspects of the disclosure. The examples discussed herein were chosen and described in order to explain the principles and the nature of various aspects of the disclosure and its practical application to enable one skilled in the art to utilize the aspects of the disclosure in various manners and with various modifications as are suited to the particular use contemplated. The features of the solutions, aspects and the embodiments of the disclosure described herein may be combined in all possible combinations of methods, apparatuses and systems. It should be appreciated that the aspects of the disclosure presented herein may be practiced in any combination with each other.

It should be noted that the word“comprising” does not necessarily exclude the presence of other elements or steps than those listed. It should further be noted that any reference signs do not limit the scope of the claims. List of reference numerals:

100 torsion spring system

1 10 elongated shaft

120 winding plug

130 first torsion spring

132 first end of the first torsion spring

134 second end of the first torsion spring 140 second torsion spring

142 first end of the second torsion spring 144 second end of the second torsion spring

150 first support bearing plate

152 first hole of support bearing plate

154 second hole of support bearing plate

155 first bearing

156 opening of first support bearing plate

157 rim of first bearing

159 female part of the first support bearing plate

160 second support bearing plate

165 second bearing

170 first bayonet plug

171 body of first bayonet plug

172 first pin of first bayonet plug

174 second pin of first bayonet plug

180 second bayonet plug

190 lintel profile

195 winding drum

198 garage door