Abrading – Precision device or process - or with condition responsive... – Computer controlled
Reexamination Certificate
2000-03-27
2001-07-24
Banks, Derris H. (Department: 3723)
Abrading
Precision device or process - or with condition responsive...
Computer controlled
C451S047000, C451S008000, C451S045000
Reexamination Certificate
active
06264531
ABSTRACT:
FIELD OF THE PRESENT INVENTION
The invention relates to a machine as defined in the preamble of claim
1
.
BACKGROUND OF THE INVENTION
In a known machine of this kind (DE 27 51 408 A1) the reference axis is defined by a rocker bearing which is disposed on the machine bed and supports a radially projecting beam. The beam is formed with a reciprocating slide guide means along which a reciprocating slide is displaceable radially with respect to the reference axis. A pivot bearing means on the reciprocating slide defines a pivot axis which extends parallel to the reciprocating slide guide means and intersects the reference axis at a right angle. A shaft, with a spindle head secured to it, is supported in the pivot bearing means. Inside the spindle head, a spindle sleeve is guided so as to be displaced by means of a feed drive along a grinding spindle axis which intersects the pivot axis at a right angle. The spindle sleeve, which thus corresponds to a feed slide, includes a grinding spindle adapted to be driven in rotation and carrying a plate-shaped grinding disc for sharpening the toothing of a circular saw blade. When straight surfaces at the front of teeth (cutting faces) or straight surfaces at the back of teeth (clearance faces) are to be sharpened the spindle sleeve always is adjusted by the feed drive in such a way that the active front surface of the grinding disc will lie in a plane which contains the reference axis. For the grinding of oblique surfaces, the spindle head is swung about the pivot axis in one or the other direction, depending on the direction of the inclination. To accomplish that, a cross bar is fastened to that end of the shaft carrying the spindle head which is remote from the spindle head, and two rolls are supported so as to be freely rotatable on this cross bar at equal distances from the pivot axis and diametrically opposed with respect to the latter. These two rolls are arranged between a piston and cylinder unit each and an adjustable stop each in such a way that the cross bar and, together with it, the shaft carrying both the cross bar and the spindle head are swingable back and forth within a pivot range which is limited by the stops. The inert masses thus to be moved are considerable indeed because the spindle sleeve and its feed drive take part in the pivoting motion. Consequently the pivoting frequency to be achieved with back and forth swinging movements is limited.
SUMMARY OF THE PRESENT INVENTION
It is the object of the invention to improve a machine for machining workpieces which have cutting teeth, especially saw blades, such that it can operate faster than the known machine described when machining surfaces at the front or back of teeth which are oblique in alternating directions or chamfers.
The object is met, in accordance with the invention, by the features of claim
1
. Advantageous further developments are the subject matter of the subclaims.
The principle which has been essential so far for the design of machinery for sharpening the serration of saws according to which the active face of the tool had to be disposed such as to be touched by the pivot axis of the tool head, which pivot axis intersected the reference axis of the machine, is given up in accordance with the invention. According to the invention, neither the feed slide nor the reciprocating slide take part in pivoting movements of the tool head about the pivot axis. As a result, the inert mass affected by the swinging motions is only relatively small and for this reason the pivoting can be effected at high speed.
The pivot axis may be located at a distance in the order of up to about one tenth of the tool diameter from the active face of the tool, especially from the active front surface of a plate or cup-shaped tool. The influence of this distance on the machining geometry can be compensated by measures according to the invention in such a way that, once the cutting teeth are finished, it cannot be determined whether they were machined with the machine according to the invention or a known machine. Machining, in the first place, is to be understood as referring to the removal of material by grinding, but also by spark erosion in cases suitable for such work. Accordingly, the tool to be fastened on the tool spindle may be a grinding disc or an erosion disc.
REFERENCES:
patent: 3640030 (1972-02-01), Clarke et al.
patent: 4172343 (1979-10-01), Sakcriska
patent: 4461121 (1984-07-01), Motzer et al.
patent: 4712332 (1987-12-01), Smith
patent: 4837983 (1989-06-01), Fuller
patent: 4905418 (1990-03-01), Wedeniwski
patent: 4963710 (1990-10-01), Lach
patent: 27 51 408 A1 (1979-05-01), None
patent: WO 92/19406 (1992-11-01), None
Bailer Norbert
Lenard Peter
Banks Derris H.
Browning Clifford W.
Shanley Daniel
Vollmer Werke Maschinenfabrik GmbH
Woodard Emhardt Naughton Moriarty & McNett
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