| JP2005068751 | ROOF TRUSS DEVICE |
| WO/1996/013378 | REINFORCED WOOD STRUCTURAL MEMBER |
| JP03176543 | TENSED CHORD BEAM STRUCTURE |
CLAIMS
1. A system for fabricating roof trusses or similar structures from members to be set against each other, the system comprising several grippers arranged at a defined assembly plane (T) to be steered into certain locations and positions for certain members for forming a structure on them and means (CU, Dl) for controlling the operations of the system as well as means for carrying out said controlled operations, characterized in that several grippers (14) have been placed on a beam (11, 12) in the same line for a long basic member (2, 3) of the structure (1), so that the beam (11, 12) is movable in any direction (Ml, M3: M4) and rotatable (R) into a desired position.
2. A system according to claim 1, characterized in that the system comprises two beams (11, 12) for a bottom and top chords (2, 3) of the structure, respectively.
3. A system according to claim 1, characterized in that the system comprises a transfer track (7, 8) and posts (9, 10) movable on it on which posts a beam (11, 12) may be steered, whereby the assembly plane (T) is a vertical plane parallel to the plane of the transfer track. |
SYSTEM FOR FABRICATING ROOF TRUSSES OR SIMILAR STRUCTURES
FIELD OF THE INVENTION
The invention is related to fabrication of roof trusses or similar structures. More closely, the invention concerns a system for fabricating roof trusses or similar structures from members to be set against each other, the system comprising several grippers arranged at a certain assembly plane to be steered into certain places and positions for certain members for forming a structure on them and means for controlling the operations of the system as well as means for carrying out said controlled operations.
BACKGROUND OF THE INVENTION
Roof trusses or similar structures are usually fabricated on a horizontal platform. On the platform, a pattern or jig is realized in one way or other which helps to place the members in place. The chords and diagonal members are usually set manually on the platform according to a pattern and fastened then to each other by means of nail plates.
In the publication WO 2006/136653, the applicant has presented a solution in which, for assembling a structure, one or more planes are defined and several grippers and guides are arranged to move and rotate in said plane according to a control, the grippers and guides are controlled to move and rotate to certain places and positions for certain members according to the control data, and the members are set in the grippers to form the structure on them, and thereafter the structure is controlled to move on the grippers for carrying out other steps of the assembly.
The system presented by the applicant comprises as a whole e.g. the following steps and the corresponding apparatuses: - feeding the members (pieces of wood) of a structure and setting them in a controlled order at certain places to be picked up,
- picking up a member and setting it in place at an assembly plane (assembly unit) by means of suitable robot devices, e.g. a manipulator,
- prefastening the members e.g. with suitable fastening brackets by means of suitable presses and response plates,
- final fastening of the members and partial structures to each other with e.g. nail plates by means of suitable nail plate presses, and
- transferring the finished structures into a store.
For carrying out this known solution, an assembly unit according to Figs. 1 and 2 has been proposed, said assembly unit representing the closest prior art in relation to the present
invention. Fig. 1 presents a schematic example in which grippers C and guides D have by means of suitable technical devices been arranged to be moved and rotated according to control on a post B moving on rails A. Fig. 2 presents schematically how a structure formed by chords Pl and P2 and vertical and diagonal supports P4, P5, P6, P7 and P8 has been assembled on said grippers C and guides D.
A problem in the solution described in Figs. 1 and 2 is that the steering of the grippers and guides accurately into the desired locations and positions is a task which is mechanically demanding, complicated and difficult to manage.
SUMMARY OF THE INVENTION
An object of the invention is to present a system in which a structure is assembled by means of grippers in a defined plane but in which the problem described above is largely solved.
To achieve this object, a system according to the invention for fabricating roof trusses or similar structures from members to be set against each other, the system comprising several grippers arranged at a defined assembly plane to be steered into certain locations and positions for certain members for forming a structure on them and means for controlling the operations of the system as well as means for carrying out said controlled operations, is characterized in that several grippers have been placed on a beam in the same line for a long basic member of the structure, so that the beam is movable in any direction and rotatable into a desired position.
In a preferred embodiment, the system comprises two beams for a bottom and top chords of the structure, respectively.
In a preferred embodiment, the system comprises a transfer track and posts movable on it on which posts a beam may be steered, whereby the assembly plane is a vertical plane parallel to the plane of the transfer track.
It is clear that in comparison to e.g. the known solution presented in Figs. 1 and 2, the assembly unit is in this way made significantly simpler in structure and operation, steadier and more reliable.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in more detail below with reference to the accompanying drawings, in which:
Figs. 1 and 2 present a prior art system and the usage of it; Figs. 3 and 4 present schematically in front and side view, respectively, an example of a system according to the invention;
Fig 5 presents schematically an example of a part of a roof truss to be assembled; and Figs. 6 to 8 present the usage and operation of the system of Figs. 3 and 4 in the assembly of the part of the roof truss of Fig. 5.
DETAILED DESCRIPTION OF THE INVENTION
A prior art assembly unit has been described above with reference to Figs. 1 and 2. In a system according to the invention presented schematically in Figs. 3 and 4, two posts 9 and 10 have been arranged to move under control on rails 7 and 8 in the way indicated by arrows Ml. The rails 7 and 8 have been supported and suspended, respectively, e.g. on the floor and ceiling constructions of the working room (support and suspension solutions not shown) and form a transfer track on which the assembly unit is transferred at need as other steps of the assembly are carried out.
Beams 11 and 12, which are horizontal in their basic position, have been coupled by means of corresponding devices 13 to the posts 9 and 10 and are on them movable and settable in different positions under control. The devices 13 include mechanisms by means of which they move the beams laterally in relation to the posts, as indicated by arrow M3, and are moved according to control on the posts 9 and 10, as indicated by arrows M4. The devices 13 include also joints so that the beam may be rotated in relation to the post, as indicated by arrows R. The devices 13 as well as devices 15 and 16 may be realized by means of generally known movement control technology and related mechanics.
Additionally, the devices 13 include mechanisms by means of which the beams 11 and 12 may be locked at certain locations and positions in relation to the posts 9 and 10.
Grippers 14 have been arranged to move according to control on the beams 11 and 12, as indicated by arrows M2. Accordingly, each gripper 14 may be steered into a certain location on the corresponding beam and then be locked in place. The locking may work by means of a compressed air brake or a magnet. Also the jaws 18 of the grippers are provided with control and mechanics by means of which they may be opened and closed in the way indicated by arrows M5.
As apparent from the above, the assembly of the roof trusses or similar structures is automated in the system according to the invention. As presented in Fig. 3, the system may comprise e.g. a central control unit CU and there data Dl for the control, the data defining the structure or partial structures to be assembled, their members, the positions of the members in relation to each other and the joining of the members to each other. Control signals Sl ... Sn leave from the control unit to different parts of the system. The data Dl may comprise e.g. the accurate dimensions of all members and definitions of their positions, the definitions of the gripping points and angles for each member and, respectively, for each
gripper or group of grippers, definitions of the locations and positions of the nail plates and so on. The data Dl may comprise the data about structure and its members also in accordance with the data of certain 3D applications, whereby it is possible to use e.g. laser or other optical applications or machine vision for checkings and alignments. There are many alternatives for persons skilled in the art for realizing this kind of systems, and the realization of the control depends on the way in which the equipment of the system and the control and driving devices are realized. In practice, the realization may be e.g. such that full details in accordance with certain specification are included in the central database from which the necessary information is searched and loaded to the different parts of the system for being possibly first worked up and then utilized there. These alternatives or any examples of them are not described here in further detail because it is not necessary for understanding the invention and because the realizations of necessary databases are obvious routine measures for a person skilled in the art when the equipment, systems and programs used for the realization have been selected. The movement control of the posts and the corresponding devices 15 and 16 moving them on the rails are included in the above described generally known technology which is not described here in further detail. The devices 15 and 16 comprise also mechanisms by means of which the posts 9 and 10 may be locked in place according to control.
The broken line T in Fig. 4 indicates a plane going through the grippers, on which plane a roof truss or other corresponding structure is assembled in an assembly unit formed in the way described above.
Fig. 5 presents as a simple example a half 1 of a roof truss, which half may be assembled by means of the system according to the invention. The structure 1 comprises long basic members, i.e. the bottom chord 2 and the top chord 3, and as the other parts a vertical support 4 and diagonal supports 5 and 6. The assembly of the structure is advantageously carried out so that first the bottom and top chords 2 and 3 are set in place and then, advancing towards the opening direction of the structure, the support members 4, 5 and 6.
The assembly takes place in the way described schematically and simply in Figs. 6 to 8. The necessary information about the structure to be assembled and its members is in the database of the system. In Fig. 6, the posts 9 and 10, the beams 11 and 12 and the grippers 14 have been steered on the basis of said information at proper locations and positions. First, the beams 11 and 12 are steered into such locations and positions that the bottom chord and top chord are set at proper locations and positions as they are brought and squeezed fast in the grippers 14 of the beam 11 and the beam 12, respectively. In this step, it must be taken into consideration also where the vertical and diagonal supports 4, 5 and 6 will be located
and the fastening of the members to each other. Finally, the members are fastened to each other by means of nail plates, and the press used for the fastening needs enough room also around the junction and the nail plates.
Fig. 6 shows how the posts 9 and 10, beams 11 and 12 and grippers 14 are set in this case. Their original positions which are different from the final positions are indicated by broken line. The post 10 is moved as indicated by arrow Ml. The grippers 14 are moved on beams 11 and 12 in the way indicated by arrows M2. The beam 12 is transferred laterally in relation to the post 9 in the way indicated by arrow M3 and lowered by means of the devices 13 on the posts 9 and 10, respectively, in the way indicated by arrows M4 so that the beam 12 is at the same time rotated in the way indicated by arrows R.
In Figs. 7 and 8, the chords and other members of the structure are slant-lined for clarifying the figures. In Fig. 7, the chords 2 and 3 have been set in the jaws 18 of the grippers 14 in the way indicated by arrows in steps I and II, respectively, by means of e.g. a suitable manipulator (not shown). Thereafter, they have been pressed with a suitable pressure in place in the jaws of the grippers. As the chord members almost always are to some extent curved or warped, the grippers which are located in straight line on a beam will straighten them in this phase. Also suitable prestresses are often desired for the structures, whereby e.g. the chords are during the assembly bent in a certain way before setting the other members in place and fastening the members to each other. The beams 11 and 12 and the grippers are realized so that their operational capacity and accuracy are maintained in these actions and their materials and parts endure the forces directed to them.
After that, first the vertical support 4 and then diagonal supports 5 and 6 are set in place (Fig. 8) in the way indicated by the arrows in steps III, IV and V, respectively. At the same time, the members are fastened to each other preliminarily by fastening brackets 17 which is made by means of suitable presses (not shown) included in the system.
Here above a simplified example of the system according to the invention and its operation have been described. What is essential in the invention is that the assembly unit comprises for long basic members of the structure, normally for bottom and top chords, beams which are steerable to certain locations and positions and comprise several grippers in the same line. In this way the assembly unit is made operationally simple and reliable.
It is obvious that the realizations of the technical details may vary in many ways. There may be e.g. only one or more than two posts arranged to move on the rails, on which posts the beams according to the invention are movable under control and settable in different positions. Instead of the transfer track formed by the posts moving on the bottom and top rails, a solution is possible in which a bottom rail and a carriage with a post moving on it
have been constructed so that there is no need for a top rail. Then, the system would be easier to overhaul, for example.
The invention may vary within the scope of the accompanying claims.
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