The subject invention concerns a method of installing door spring systems, according to which the cable wind¬ ing drum, the spring, and the shaft associated with the door are secured above the door opening so as to allow the door and the cable winding drum to be inter¬ connected by means of the cable.

The main purpose of the subject invention is primar¬ ily to make it possible to assemble and install the components incorporated in a spring system in a simple manner without causing hazards to the workmen installing the door but also to allow installation of the door without the aid of expensive professional workmen, thus making it suitable for do-it-yourself jobs. This is ^• achieved by means of a suitable unit which is easily installed in operative position and interconnected with the associated door.

This purpose is achieved by means of a method of installing door spring systems in accordance with the subject invention, which method is essentially characte- rized by winding a length of cable adequate for the intended door onto the cable winding drum, attaching the drum to the shaft, placing a torsion spring over the shaft and .attaching said spring securely to said shaft and connecting said spring with fitting members mounted for turning movement about said shaft, one at each spring end, whereby a spring unit is formed, lifting the unit thus formed and securing it in a premounted bracket, and thereafter interconnecting the cable and the door while the spring is in its relaxed position and unreeling the cable while the door is in its raised position.

One preferred embodiment of the invention will be described in closer detail in the following with reference to the accompanying drawings, wherein Fig. 1 illustrates the installation of a door spring

system while lifting the spring unit and its associated parts.

Figs. 2-4 illustrate various stages of the installa¬ tion procedure. Fig. 5 is an exploded view of a part of a door spring system.

Figs. 6-11 illustrate various stages of the installa¬ tion and

Fig. 12 illustrates a door equipped with the door- spring system after completed installation.

A door spring system 1 in accordance with the inven¬ tion comprises at least one spring 3, which is coupled to a shaft 2, and a cable winding drum 4. By means of a cable, these components are to be connected to the door 5 which is guided along door guiding tracks 7 extending in the intended direction of movement 6 of the door. The door spring system also includes attach¬ ment brackets provided above the door opening 11 to support the guiding channels. The spring 3 is preassembled into a unit 12 which preferably comprises a pair of springs 3, 3 , each one connected to its respective one of spring shafts 2, 2 , two cable winding drums 4, 4 , each one connected to its respective one of shafts 2, 2 , and a coupling member 13 interconnecting said shafts 2, 2 , as well as fitting members 14, 14 , each one mounted on its respective one of said shafts 2, 2 . In the fully in¬ stalled position illustrated e.g. in Fig. 1, each fitting member 14, 14 is connected to its associated one of brackets 15, 15 , which are secured above the door open¬ ing 11. Each bracket 15, 15 is formed with a number of slots 17, 18, 19 which open in the direction indicated by 16 and which are designed to receive therein the aassssoocciiaatteed shaft 2 or 2 and the associated fastener 20 or 21 E Eaacclh bracket 15, 15 preferably has an oblique edge 22 including the slots 17, 18, 19, with the centrally

located slot 17 intended for reception therein of the shaft whereas the slots 18 and 19, positioned on either side of slot 17, are intended for reception of the fasteners 20 and 21, respectively. The reception slots 17-19 extend outwards essentially perpendicularly to the door-defining wall 23.

The fitting members 14, 14 preferably are split into two parts which cooperate in pairs for exerting clamping action. The fitting member parts 14A, 14B and 14 A, 14 B of each pair are positioned one on either side of the associated bracket 15, 15 with which they are intended to be connected. Between the two parts 14A, 14B and 14 A, 14 B of each fitting member extend, in the preinstallation position, said bolt fasteners 20, 21 which are arranged to clamp the fitting member parts against the brackets 15, 15 sandwiched between said fitting member parts.

Also the centrally positioned spring shaft coup¬ ling member 13 is arranged to be supported at the centre of said unit, as illustrated in Fig. 9, by means of a centre bracket 24 attached to the wall 23. Also the centre bracket may be formed with slot recesses 8 in order to receive therein screws fasteners 10 for securing a shaft-mounted flange 9 to the centre bracket 24. The split spring shaft fitting members 14, 14 are placed on the spring shaft 2, 2 with a shaft bear¬ ing 25 sandwiched between the fitting member parts 14A, 14B and 14 A, 14 B, respectively. Said shaft bearing 25 is secured to the shaft and fixed in the desired position, e.g. by means of a number of clamping screws 26.

The springs 3, 3 preferably are torsion springs, more precisely helically coiled springs of the torsional type. The springs are coiled about and extend along their associated shaft 2, 2 . One of the spring ends 3A, 3 A, is attached to a spring attachment member 27,

27 which may be secured to the shaft 2, 2 , for in¬ stance by means of a number of clamping screws 28. By means of the opposite end 3B, 3 B, the springs 3, 3 are secured to the respective fitting member 14, 14 , which is mounted for free rotational movement about the shaft 2, 2 , preferably to the fitting member part 14A, 14 A positioned adjacent the associated spring 3, 3 , whereby said spring end 3B, 3 B will tend to rotate together with its associated fitting member part 14A, 14 ¹ A.

The brackets 15, 15 preferably are arranged to be removably attached to the upper ends 29A, 29 A of door guide track sections 29, 29 which extend vertically when installed in the appropriate position for guidance of the door. Consequently, the brackets may easily be connected to the tracks on the ground, for instance by means of bolts 30, and be screwed to the wall 23 only when they have been placed in their final, fully mounted position, by means of screws 31. In accordance with the illustrated embodiment the fasteners 20, 21 are received in apertures 32-35 passing through attachment lugs 36-39 positioned in diametrically opposed in each fitting member part.

A door spring system 1 in accordance with the subject invention thus may be produced in the following manner. One end 3A, 3 A of the spring 3, 3 is non-rotationally secured to the shaft 2, 2 to which the cable 40, 40 or other pulling means may be attached in such a manner that said spring end is non-rotational with respect to the shaft 2, 2 , whereas the opposite spring end 3B, 3 B is attached to its associated fitting member 14, 14 which is mounted on the shaft 2, 2 for free turning movement about the latter. Each fitting member is prepared for attachment to and securement in the matching, slotted attachment brackets 15, 15 . Before lifting the spring unit, thus preassembled at ground level to allow it to be received in the slots 17-19

formed in said brakcets 15, 15 , the latter are attached in the desired position above the door opening 11.

More precisely, the fitting members 14, 14', prefer¬ ably consisting of the paired fitting member parts 14A, 14B and 14 A, 14 B, respectively, are preassembled by means of the bolt fasteners 20, 21 in such a manner that a gap of e.g. 5 mm is formed between the fitting member parts of each pair. In this gap the associated attachment bracket 15, 15 may be received and clamped in position, sandwiched between said fitting member parts, subsequently to the preassembled spring unit having been lifted manually by the workmen 41, 42 or mechanically. The latter procedure is not shown in the drawings and normally it is no longer necessary. Preferably, the fitting member parts 14A, 14B and 14 A, 14 B are turned into the desired positions prior to being bolted together in such a manner as to ensure a predetermined angle relatively to the departure of tthhee ccaabbllee ffrroomm tthe drum 4, 4 in relation to the total cable winding A.

Onto the cable winding drum 4, 4 is wound the length of cable that is appropriate for the door 5 in question. The positions of the various parts which are respectively non-rotational and non-displaceable rela- tively to the shaft are easily determined before the unit is lifted. However, these positions could also be established after the assembly, lifting, and attachment of the unit in the brackets 15, 15 , following tightening of the bolts 20, 21 and clamping of the brackets 15, 15 between the fitting member parts 14A, 14B and 14 A, 14 ¹ B with the shaft 2, 2 and the bolts 20, 21 being received in their respective one of slots 17-19.

The means making up a door spring unit 1 in accord¬ ance with the invention, which means comprise a spring 3, 3 coupled to a shaft, and a cable winding drum 4,

4 , said spring and drum being connected to the door

5 which is guided in door guide tracks 7, 7 extending

in the intended direction of door movement 6, also include the brackets 15, 15 for attachment of the door spring unit. As mentioned previously, the brackets are formed at one of their edges with open slots 17-19 for free reception therein of the fitting members 14, 14 , the shaft 2, 2 and the fasteners 20, 21 of the preassembled spring unit after lifting thereof. Slots 17-19 extend in a direction essentially perpendicularly outwards from an attachment piece 43, 43 , which may be an angle iron and which is connected to a wall 23, and the two bolt fastener receiving slots 18, 19 are positioned on either side of the central shaft reception slot 17. Before the spring is placed in position, a length of wire A, appropriate for the door in question, is wound onto the cable winding drum 4, 4 which is secured to the shaft 2, 2 . A suitable torsion spring 3, 3 is placed over the shaft 2, 2 with one spring end 3A, 3 A secured to the shaft 2 , 2 while the opposite spring end 3B, 3 B is secured to the fitting member which is mounted on the shaft for rotational movement about the latter. In this manner, a compact and easily manageable spring unit 12 is obtained which may be lifted and in¬ stalled in position in the premόunted appropriate brackets 15, 15 above the door opening 11 of the associated door. The two cable ends 40A, 40 A are thereafter attached to the bottom rolling guide pins 44, for instance by threading the cable ends over the pins and locking them in position by means of door guide member 45, which are attached to the associated door leaf 5A, for instance by means of screws 46.

The cable 40, 40 is thereafter connected to the door 5, the spring then being in the relaxed position. This position corresponds to the elevated position of the door wherein the latter is locked underneath a ceil- ing, as shown in Fig. 10, above the space that the door 5 is intended to close against the action of the spring 3, 3 . The cable 40, 40 is thereafter unreeled from

the cable wionding drum 4, 4 while the door 5 is in the elevated position, for instance with the aid of a pulling member 100 removably attached to the cable. The cable loop 101 thus formed is passed about lower pulley members 102 in order to provide the spring bias appropriate for the door 5.

Previously, before the unit 12 is secured in posi¬ tion, the fitting member parts 14A, 14B and 14 A, 14 B incorporated in the unit 12 are set in the desired angular position relative to the direction of departure of the cable being unwound from the cable winding drum 4, 4 . Also the end positions of the spring ends are set and the ends are secured to the spring shaft 2, 2 in dependence on the desired spring tension. The installation operation also includes introducing the spring shaft 2, 2 and the fastener members 20, 21 incorporated in the fitting members 14, 14 radially in the direction indicated by 103 relative to the spring shaft into the associated open-mouth slots with sub- sequent tightening of the fastener members 20, 21 to clamp the sandwiched brackets 15, 15 in position.

The fitting member parts 14A, 14B and 14 A, 14 B preferably are interconnected by means of bolt fasteners 20, 21 in such a manner that a gap is formed between said parts for reception therein of said brackets 15, 15 ¹ .

The invention is not limited to the embodiment described herein and illustrated in the drawings but could be modified in a variety of ways within the scope of the appended claims without departure from the inven¬ tive idea.