Metal deforming – By use of non-deforming work-gripping clamp and relatively... – By individually non-deforming clamps
Reexamination Certificate
1999-10-01
2001-02-20
Crane, Daniel C. (Department: 3725)
Metal deforming
By use of non-deforming work-gripping clamp and relatively...
By individually non-deforming clamps
Reexamination Certificate
active
06189359
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a twisting machine for polygonal cross-section bars. Twisting machines of this kind, called also torsion machines, have an independent jaw chuck firmly fitted on a mandrel and a counteracting support, which is slidely connected to a prismatic guide parallel to the mandrel. A bar to be twisted is centered on the chuck and the support.
DESCRIPTION OF THE RELATED ART
The machines of this kind are affected by a problem related to the type of poly-angular jaws, having in general surfaces at right angle, which are necessary to hold polygonal cross-section bar against the rotation. When a bar has to be centered on the chuck and the counteracting support, their jaws must match, or more properly the space defined by the jaws of the chuck is necessarily equal and angularly equally arranged to the space defined by the counteracting support. One must try to achieve this position of the chuck by rotating the geared motor driving the mandrel, which is difficult to be achieved after several attempts by controlling the machine power.
In twisting machines known a nonius with a pointer indicating precisely the desired position is provided. However, the difficulty in achieving this position is alleviated only a little.
A difficulty similar to that one meets in centering a bar to be twisted is founded in removing the same, when the machining operation is finished or during a step which requires that the points of clamping the bar on the chuck or on the mandrel are changed. Obviously, when the mandrel is stopped, the bar remains stressed. Therefore, until now, in the operation one tries through the control of the geared motor power, to release the bar from the elastic stresses present inside so that the bar doesn't counteract the jaws to be removed.
SUMMARY OF THE INVENTION
A main object of this invention is therefore to provide a twisting machine which allows machining time to be shortened notably.
Another object of this invention is to make easier the steps of centering a bar and removing the same in a safe way for the worker.
These objects are achieved by the present invention which provides, such as defined and characterised broadly in the first one of the accompanying claims and in its more meaningful particular embodiments in the subsequent claims, a twisting machine for polygonal cross-section bars having an independent jaw chuck fitted on a mandrel and a counteracting support slidable on a prismatic guide, which is firmly connected to the machine and parallel to said mandrel, characterised in that said independent jaw chuck comprises mutually co-operating
means of rotary connection between said mandrel and said chuck for the free rotation of the chuck;
means of mutually engagement provided on said mandrel and, respectively, on said chuck, which are adapted to drive into rotation said chuck by means of said mandrel, after a free rotation of said mandrel along an arc with an angle less than a round angle.
REFERENCES:
patent: 1887375 (1932-11-01), Hightower
patent: 2628653 (1953-02-01), Sherman
patent: 4019356 (1977-04-01), Bohl
patent: 5771726 (1998-06-01), Bibby et al.
patent: 75787 (1894-06-01), None
patent: 610277 (1935-03-01), None
patent: 560041 (1944-03-01), None
Caporusso Alessandro
Caporusso Mario
C.M.L. Costruzioni Meccaniche Liri S.r.l.
Crane Daniel C.
Young & Thompson
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