Improvements in Machines for Cutting or Grinding Metal Balls.
Year: 1897

page_text: Date of Application, 24th Feb., 1897-Accepted, 27th Mar., 1837
COMPLETE SPECIFICATION.
Improvements in Machines for Cutting or Grinding Metal Balls.
I, FRIEDRICH FISCHER, of Schweinfurt-on-Main, in the German Empire,
Manufacturer, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
This invention relates to machines for cutting or grinding metal balls wherein
there are employed a quickly revolving cutting or grinding grooved disc or plate
and a second grooved disc or plate opposite the first and made in one or two parts
in which latter case the halves revolve with different velocities relatively to one
another.
These machines have the disadvantage that they do not cut or grind the balls
in the grooves exactly round, especially when the diameter of the balls is small.
This is occasioned by the balls not being subjected to sufficient friction in the
groove of the single or divided guiding plate and have consequently not sufficient
hold to withstand the powerful action of the cutting or grinding disc to the extent
required in order that the balls in their passage round the guiding groove be rotated
on their own axes at a constant velocity.
This disadvantage is overcome according to this invention by making the
divided or undivided guiding disc of a metal capable of being magnetised, and
magnetising it in a suitable manner just sufficiently to attract the balls in the
guiding groove to such a degree as to ensure that they rotate with a constant
or approximately constant velocity during their passage round the guiding
groove.
To enable my invention to be fully understood I will describe it by reference
to the accompanying drawing, which shews as an example a machine having a
magnetisable guiding disc made in two parts one of which is fixed whilst the other
rotates.
In the said drawing:
:-
Figure 1 is a vertical section through the machine.
Figure 2 is a plan of the driving gear.
Figures 3 and 4 are vertical sections through the two halves of the divided
guiding disc.
To facilitate the explanation I will first describe the general construction of the
machine which however forms no part of the invention.
a is a frame or support in which is rotatably mounted a vertical shaft or
spindle upon the upper end of which is keyed the disc which carries the
grinding grooved ring d. The central portion of the shaft 6 is enclosed in a
sleeve e which is screwed into the frame or support a and around which the disc f
revolves.
The outer rim of the disc forms the inner half g of the guiding groove. The
outer half h of this groove is rigidly secured to the frame a. The grinding disc c, d
is rotated at a high speed by the driving shaft through the medium of the
belt and the bevel wheels k.
This shaft which is provided with fast and loose pulleys also carries a worm m
which engages with a worm-wheel n rigidly connected with the boss of the lower
disc f and which thus imparts a slow motion to the inner half g of the guiding
groove.

page_text: According to my invention each of the two halves g and h of the guiding groove
is made of a metal capable of being magnetised and each is provided with a coil
of wire o the said coils being preferably placed in recesses in the said halves as
shewn in Figures 3 and 4. An electric current derived from any suitable source
is sent through these coils o so that the two halves of the groove have at their
upper ends poles of the same or opposite names.
As the inner half of the groove revolves the current must be communicated to
its coils by means of rings, p which may be fixed or movable with the said half as
shewn in Figures 1 and 4. If the guiding groove is in one piece and revolves
in a direction opposite to that of the grinding disc, these rings must also be
employed.
It is advantageous to insulate the divided or undivided guiding disc from the
frame so that the groove only can be magnetised.
The strength of the current is so regulated, that the magnetism generated in
the divided or undivided guiding groove, exerts just enough attraction on the balls
in the groove to ensure that they revolve with a constant velocity during their
passage round the guiding groove.
In practice it is advantageous to switch off the electric-current occasionally and
then to pass a current of air or water through the guiding groove in order
to blow or wash away the small particles of metal which may have collected
therein.
It is to be noted that the machine can be arranged with its dises reversed, that
is to say the divided guiding groove can be placed above and the cutting or
grinding groove below and further that the cutting or grinding ring need not be
grooved but can be in the form of a flat ring or a flat disc and can be rotated.
excentrically to the guiding groove, for which purpose it is only necessary to
support the axle of the cutting or grinding disc excentrically in the sleeve e which
is widened for that purpose.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, 1 declare that what I
laim is :-
1. In a machine for cutting or grinding metal bails of the kind wherein a
divided or undivided guiding disc and a cutting or grinding ring or disc are
employed forming the guiding groove of a metal capable of being magnetised and
magnetising it in a suitable manner permanently or intermittently and to such a
degree that it ensures the balls in the guiding groove revolving at a constant or
nearly constant velocity during their passage round the guiding groove, substantially
as, and for the purpose, herein before described.
2. The manufacture and use of the improved machine for cutting or grinding
metal balls herein before described and illustrated in the accompanying drawing.
Dated this 11th d 1007
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.