Method and Apparatus For Manufactring a Nail Plate Truss Without Setting

Abstract

A method and an apparatus for the manufacture of a nail plate truss (2) without setting, said nail plate truss including first-side nail plates (3) of the truss, second-side nail plates (3) of the nail plate truss, and struts (4) joined together by nail plates. According to the inventive method, the structure of the truss is stored in an electric control system (20), and the nail plates (3) and struts (4) for a truss are brought into their positions required by the truss structure onto a horizontal assembly table (5), as controlled by an electric control system, using handling members (11) separate from the assembly table, the parts (3, 4) of the truss being positioned into their positions based directly on positioning of the handling member (11) transporting them.

Description

TECHNICAL FIELD[0001]The invention refers to a method defined in the preamble of claim 1 for the manufacture of a nail plate truss. According to the preamble of claim 7, the invention also relates to an apparatus for manufacturing the nail plate truss.BACKGROUND OF THE INVENTION[0002]The manufacture of roof trusses and other corresponding nail plate trusses usually used in construction includes different steps of work. Wooden struts for the truss, cut to size and machined to have desired form, are traditionally laid on the assembly table in an order required by the final structure, and in contact with each other. Subsequently, the parts are joined together by nail plates pressed into their upper surface, connecting the parts together. Next, the nail plate truss is turned upside down for connecting the nail plates to the node joints of the struts on the other side of the truss, too.[0003]In its traditional form, the manufacturing method described requires a lot of handwork, and is re...

AI Technical Summary

Benefits of technology

[0009]The invention is especially intended to disclose a novel automatic method and apparatus for manufacturing a nail plate truss without a setting, by means of which method and apparatus trusses having different shape and size can be manufactured effectively and with high accuracy, and which apparatus, compared to prior art apparatuses, is simpler and requires less maintenance.SUMMARY OF THE INVENTION

[0018]Performing the steps described above as controlled by the electric control system means that said steps are performed automatically by means especially provided for each step. For transferring and positioning of parts, for example, handling members can be used operated by precisely positioned electric high-speed linear motors provided with slides for linear motors moving in a magnetic trail, to which the handling members have been fastened. By automation, the manufacture is accelerated, and positioning the parts becomes more precise while simultaneously reducing the possibility of errors compared to manual assembly. Said pick-up positions may be storages or intermediate positions for parts outside the assembly table or in the area of the table, to which parts needed at each time are brought one by one. In their respective pick-up positions, both the struts and the nail plates are preferably in precisely defined locations in order to be gripped at given locations, when picking up by automatic handling means. At this, the location of the parts is under control during the entire transfer. If the pick-up position is a storage containing several different parts, the parts are preferably provided with identifications, e.g. bar codes or the like allowing the handling members to identify, for example, the strut needed in each case.

[0025]According to the invention, the apparatus for manufacturing the nail plate truss without setting includes an electric control system in which the structure of the truss, and the positions of its parts can be stored. The control system may include, for example, both a computer and software installed therein, and data transfer connections between the computer and the apparatuses controlled by it. The control system allows the nail plate trusses to be manufactured automatically, without manual working steps, thus contributing to the effectiveness of the manufacture, and decreasing the production costs. The accuracy also is improved as human errors, for example, in measuring the positions, are eliminated. Such a control system also can be integrated as a part of the remaining production control system of the factory, allowing the apparatus to be operated centrally as a part of the controlled production line.

[0033]The handling means also may comprise vibrating means for vibrating the support surface, so as to increase the effectiveness while pressing the nail plate and the strut against each other.

[0034]In a preferred embodiment of the invention, the transfer means first include linear guides arranged above the assembly table, substantially parallel thereto, carrying the handling members for transferring the handling members along the first linear guides. Furthermore, the transfer means comprise second linear guides supported above the assembly table, for example, to the frame of the apparatus, carrying the first linear guides, and arranged perpendicularly thereto, likewise disposed substantially parallel to the assembly table for transferring the first linear guides therealong. Hence, by means of linear movements in two directions, the handling member can be brought to every given position above the assembly table. The linear guides extend preferably over the entire handling line and so far therebeyond that fetching parts from pick-up positions outside the assembly table, and transfer of the truss away from the assembly table is enabled. Preferably, the handling member also is arranged to be horizontally movable, transversely in relation to the first linear guide carrying it. This allows moving and assembling of the struts also parallel to the first linear guide, by holding the strut with the handling members of the first linear guides. For accomplishing the movements along the linear guides, the transfer means also comprise drive means, for example linear electric motors or other drive means capable of achieving sufficient speed and positioning precision.

[0036]Utilising the inventive method and apparatus for the manufacture of nail plate trusses, different advantages are achieved, as is described above, compared to previously used methods. Firstly, the assembly of nail plate trusses in which conventionally a lot of human work was involved, can be completely automated resulting in an acceleration of the manufacture. Additionally, time is spared remarkably by the essential feature of the invention that a separate change of setting between the different truss types is not needed, since positioning of the parts is directly based on position information stored in the electric control system, and on positioning of the handling members as controlled by the control system. By automation, the precision also will be improved and the possibility of errors minimised. The automation system can be incorporated as a part of the remaining control system so as to be operated by the production control system of the entire production plant. According to the invention, the nail plate truss is manufactured without turning upside down known from prior art, for fastening the second-side nail plates. This eliminates the risk for truss to be distorted during turning. Neither are complicated and failure-prone to turning means needed known from prior art apparatuses. Unlike the stops according to prior art, movable in the assembly table, the apparatus is not sensitive to problems caused by wooden material loosening from the trusses, and other impurities, as the assembly table may be very simple, for example, merely a level of steel.

Problems solved by technology

In its traditional form, the manufacturing method described requires a lot of handwork, and is relatively slow.

On the other hand, changing the truss type requires a time-consuming change of setting.

Mechanical parts and grooves of the assembly table, however, are susceptible to wear and, at least to some extent, to problems caused by fouling.

Furthermore, the truss parts still are laid manually which is both time-consuming, and includes plenty of possibilities for errors even if assisted, for example, by projecting the parts' position on the assembly table using a laser light.

By such a turning member, however, the complexity of the apparatus is increased, and utilises more movable parts susceptible to wear and damage.

As can be seen from above, even today the manufacture of trusses is rather time-consuming, requiring still fairly many manual steps of work which, in addition to causing costs, tends to increase errors and inaccuracies.

The mechanisms moving the stops in the assembly table, needed for forming the setting, are susceptible to wear and problems caused by fouling.

Turning a half-finished truss upside down adds to the difficulties of the method, and renders the joints of the truss susceptible to loosening and dislodging.

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