Metal working – Plural diverse manufacturing apparatus including means for... – Binding or covering and cutting
Reexamination Certificate
2000-08-09
2003-05-13
Vidovich, Gregory M. (Department: 3726)
Metal working
Plural diverse manufacturing apparatus including means for...
Binding or covering and cutting
C029S787000, C029S281300, C029S897340, C140S112000
Reexamination Certificate
active
06560834
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention concerns a method to form metallic cages for reinforcement purposes and the relative device.
The invention is employed to facilitate, accelerate and simplify the positioning of the stirrups and the longitudinal rods in metallic cages, and also the operations to attach the rods to the stirrups.
The metallic cages as used with the invention are employed as reinforcement in load-bearing structures in reinforced concrete such as beams, pillars, foundations, etc.
Metallic cages used in load-bearing structures in reinforced concrete comprise a plurality of longitudinal rods, normally round pieces, possibly ribbed and/or shaped, with which a plurality of transverse stirrups, distanced lengthwise, are associated.
The stirrups can be of any shape whatsoever, for example polygonal, circular, in a mesh, etc., at least partly closed.
In the state of the art, the metallic cages are assembled manually, for the most part, because, among other reasons, it is difficult to automate the assembly operations; these difficulties derive from the great variety of the structural characteristics of the metallic cages.
The composition of the metallic cage varies both according to the geometry of the load-bearing structure where they are to be used, and also according to the stress to which the structures are subjected.
Therefore, it often happens that metallic cages which are equivalent in size and geometry have to reinforced with a variable number of rods, or with reinforcement rods arranged differently inside the stirrup, or with stirrups having a differentiated interaxis.
This causes considerable operating difficulties for the assembly workers who are obliged to perform continuous measurements before welding, with a high risk of error.
Another considerable problem is the positioning of the longitudinal rods, which can reach lengths of as much as 12 meters and more, inside the stirrups, or inserting the stirrups outside the rods if the rods are already arranged positioned on trestles or other supporting means.
A further considerable problem is to maintain the longitudinal rods and the stirrups in position during the welding and tying operations.
Yet another problem is to ensure the axial alignment of the longitudinal rods.
All these problems become even more important when the stirrups to be assembled are wide, because of the difficulty of positioning and supporting them in an erect position while the cage is: being formed.
There are solutions known to the art which use partly automated machines, or cage-producing machines, which limit the manual operations required for assembling the cage and make the operations for the workers easier.
These machines comprise means to retain and position the longitudinal rods cooperating with movable means to transport and position the stirrups in a controlled manner.
The movable means, as they move parallel to the longitudinal rods, allow the stirrups to be picked up and progressively distributed by the worker along the whole length of the cage.
Although such machines are extremely efficient, they may be too complex, sophisticated and over-sized for requirements, they need heavy investment, equipping operations, complex systems to move and control them, large spaces for manoeuvring, and equipment which requires constant maintenance and constant attention by the workers.
Moreover, in the case of very large metallic cages, the machines are unsuitable to support and stably maintain the stirrups to be assembled in an erect position, especially when the latter are very wide.
Therefore, if on the one hand these machines meet the need of automating the construction of a metallic cage almost completely, on the other hand they have problems of expense, simplicity and practicality, both during construction and during use.
U.S. Pat. No. 5,350,162 describes a device to form metallic cages comprising a plurality of pairs of retaining elements with a vertical development able to be reciprocally separated according to desired values in both a longitudinal and transverse direction, which serve to position the longitudinally separated stirrups in an erect position.
The rods to be attached to the corners of said stirrups are inserted longitudinally inside the stirrups.
This document does not provide in any way to vertically displace the rod support elements with respect to the stationary stirrups, or vice versa, in order to facilitate the positioning and attachment of the rods to the various vertical levels of the stirrups.
Therefore, with this device, to position the rods at the highest levels inside the stirrup, at least two people need to raise one rod at a time, holding it at the end, and take it to the desired level, and a third person has to carry out the attachment operation; otherwise, the same person has to support the rod with one band while at the same time he does the tying operation with the other hand.
It is obvious that this operation not only necessarily requires the intervention of at least two people, but also involves a considerable physical effort and considerable care, with the risk on the one hand of making an unsatisfactory attachment and on the other hand of causing accidents, particularly in the case of very long and heavy rods.
Another disadvantage comes from the fact that, if on the one hand there is no problem of positioning in the case when the rods are attached only in correspondence with the upper inner corners of the rod, on the other hand, in the case when the rods are positioned at one or more intermediate levels in height, a considerable problem is created concerning the accuracy of the positioning.
In this case, which is the more frequent one in the production of metallic cages, the workers are obliged to take reference measurements on the sides of the stirrup according to the design specifications of the cage, and then try to respect these reference measurements while they are supporting long, heavy rods at the ends and tying them.
EP-A-0.376.765 describes the use of identification elements to indicate the position where the stirrups have to be located with respect to the longitudinal rods.
This document does not describe a method or a device to facilitate the formation of a metallic cage.
The present applicants have designed, tested and embodied this invention to overcome the shortcomings of the state of the art with a solution which combines efficiency, practicality, versatility, flexibility and economy, and also to obtain further advantages as will be shown hereinafter.
BRIEF SUMMARY OF THE INVENTION
The purpose of the invention is to provide a device to form metallic cages which will accelerate, simplify and rationalise the operations to position the rods and stirrups, whatever their size, and also the operations of welding or tying in the assembly steps.
The invention also makes possible to vary the interaxis between the stirrups extremely quickly, and to position the longitudinal rods in the correct positions established by the design plans of the cage, without carrying out manual measurements which often cause errors and lead to time being wasted.
The invention uses a plurality of seatings for means to position and retain the stirrups; the seatings are distributed lengthwise along the length of the cage to be formed.
Moreover, the invention includes means to support and position the longitudinal rods of the cage to be assembled; these means are arranged at intervals along the length of the cage.
The seatings for means to position and retain the stirrups are arranged lengthwise with a pre-defined interaxis, either fixed or variable, and cooperate with marker means which identify the position of the stirrups to be inserted according to the design specifications of the cage to be made.
In a first embodiment, the marker means are manual and the workman applies a marker element from time to time in correspondence with the seating where the stirrup is to be inserted.
According to a variant, the marker means are commanded by remote control means and consist of visual indicators which light up in correspo
Antonelli Terry Stout & Kraus LLP
BCD Marcel Wirth - Bending and Cutting Devices
Nguyen Trinh
Vidovich Gregory M.
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