Presses – Methods – With cutting or comminuting
Patent
1993-09-14
1995-08-15
Gerrity, Stephen F.
Presses
Methods
With cutting or comminuting
29432, 29798, 52DIG6, 100913, 144345, 144353, 227152, B30B 1300
Patent
active
054409772
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the production of a trussed rafter with nail plate connections.
2. Description of the Prior Art
Trussed rafters of timber members and nail plates are today produced as follows: the timber members are cut by length and at specific angles with special saws. These saws generally have four blades and the timber moves transversely with respect to the saw. The timber members are assembled in a special jig fixed according to rafter measurements and nail plates are manually positioned in the joints of the jig. The nail plates are pressed into the timber by means of clamping arrangements and a press in the jig. In the jig, the plates can be only pressed to half the full depth, whereby the final pressing takes place usually in a finalizing roller. The jig can also be of such a construction that the nail plates are fixed and pressed first on the one side and then the rafter is turned around, i.e., turned over, and the plates of the other side are fixed so that fixing of plates underneath the timber members is not necessary.
There are a lot of problems with the presently used trussed rafter production methods as follows: possibility of errors is remarkable, on the order of even up to 10 to 20 mm. These errors must be taken into account by making the plate bigger, which means a substantial increase of nail plate costs. Even though the plate size is made bigger, the final result is still unreliable, since an error in plate positioning is difficult to detect and control. direct method, i.e., usually by using a beam press or a C-press, the jig and the pressing element must be robust because of the great pressing force extended on the nail plate. If pressing is done by the roller method, measuring is largely carried out by a prefixing jig station and the final-fixing roller for the plates, as well as the conveyors between them, are expensive equipment. If the production is based on turning the trussed rafter, two separate jigs and plate positioning stages are needed, which makes the method complicated and for this reason, the method is not frequently applied. installed, a form exactly similar to the trussed rafter found, and the positions of joints and plates determined. This is usually done by manual measuring, which is a time-consuming job. For jig setting, there are also many kinds of automatic measuring units and purely data controlled jigs have also been developed. However, jigs of this kind are expensive and generally applicable only to the production of standard type trussed rafters or the jigs do not carry out the setting completely but often many manual operations are still required, e.g., positioning of joints and plates must still be determined. is remarkable, being on the order of 5% of all timber. This is mainly due to two reasons: firstly, cutting is usually done by four blade saws which always means some waste, because almost in every case a small bit has to be sawn off for timber member head formation, and secondly, the timber member length very seldom corresponds to the length of timber members to be sawn but is usually somewhat longer. This results in waste pieces that can not be used in the production. automatic stress grading. This is due to the fact that in stress grading timber members move lengthwise and thus four blade cutting and stress grading cannot be combined economically. Present cutting saws are manual and it has not been possible to combine such saws with stress grading due to the slow movement thereof. used are inherently very uneconomical. Since the grading is based on the principle that in the design for each timber member the greatest stress is determined and, accordingly, the strength requirement for this timber member is set using the principle that the weakest stress point must correspond at least to the greatest stress. Timber strength is determined by defect, i.e., by the weakest point, and this strength is almost always quite small with respect to that of the overall timber member. It is typical that i
REFERENCES:
patent: 3304106 (1967-02-01), McCormack
patent: 3435508 (1969-04-01), Sanford
patent: 3439607 (1969-04-01), Sanford
patent: 3530790 (1970-09-01), Post
patent: 3599562 (1971-08-01), Hutchens, Sr.
patent: 3685129 (1972-08-01), Jureit et al.
patent: 3771439 (1973-11-01), Mort
patent: 3867803 (1975-02-01), Platt
patent: 3888169 (1975-06-01), McNaughton
patent: 4005520 (1977-02-01), Sanford
patent: 4071061 (1978-01-01), Schneider
patent: 4104962 (1978-08-01), Castillo
patent: 4252058 (1981-02-01), Tison
patent: 4414787 (1983-11-01), Kappen
patent: 4514899 (1985-05-01), Burger
patent: 4653242 (1987-03-01), Ezard
patent: 4738071 (1988-04-01), Ezard
patent: 5234279 (1993-08-01), Poutanen
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