An Apparatus for Testing the Hardness or Efficiency of Steel or similar Balls, particularly applicable to Balls for Use in Bearings.
Year: 1896

page_text: Date of Application, 21st Aug., 1896-Accepted, 3rd Oct., 1896
COMPLETE SPECIFICATION.
An Apparatus for Testing the Hardness or Efficiency of Steel or
similar Balls, particularly applicable to Balls for Use in
Bearings.
1, WILHELM RACKE, Engineer, of Ratibor, Silesia, in the Empire of Germany,
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 :-
Balls which are to be used for ball bearings, must possess, beside other qualities,
that of being hard and tough in the highest degree. If such balls are heated too
much in the hardening process, they lose the important quality of toughness, and
the consequence is that when used in bearings they break aud cause a considerable
amount of damage. It is impossible to say from the inspection whether a ball
is a sound and good one or defective, due to over-heating; in both cases it has
the same highly polished and shining surface. The apparatus forming the object
of the present invention is destined to be used for determining beyond any doubt,
whether a ball is good or whether it has been burnt during the hardening or has
not been sufficiently hardened or bas been manufactured of inferior aleel.
.
This is attained in such a manner that the ball being dropped from a certain
height on to a block, which is as hard as glass, is caught on the rebound, the
height of the rebound being determined. A ball which has been over-heated las
not the same degree of elasticity as a properly hardened ball, and therefore does
not rebound as high as the latter. From the difference of the height of rebound
the degree of the over-heating can be determined with certainty.
The new apparatus is represented in the accompanying drawing in which
Figure 1 is a longitudinal section
Figure 2 a plan and
Figure 3 a front elevation.
The balls to be tested aro placed in a box b placed obliquely and supported by
the columns a a. From this box the balls are brought by means of a lifting
device which will be presently describel, on to the upper end of an inclined
channel c. The balls roll in this chanuel downwards and fall from its lower end
on to a block made of any suitable material such for instance as steel and having
a surface of the hardness of glass, which block is placed under the said lower end
of the channel. In consequence of their elasticity the balls rebound upwards and
fall into a box g. Between the box 9 and the steel block d there is a sliding cross
piece which can be adjusted as to its height by means of a micrometric scrow e.
If the balls are properly hardened, and therefore sound, they rebound to a
certain height and the slide f is accordingly placed at such a height that the
balls pase over it and fall into the box g. If the balls have been burnt during
the hardening process, then they will not rebound as high in consequence of their
lesser elasticity, therefore they will not be able to jump over the slide. These
inferior and useless balls are in such way separated from the good ones.
The before mentioned lifting device for the purpose of transferring the balls
from the box b to the chaunele can be understood from examination of Figures 1
and 3. A slide having a groove on its upper part is vertically reciprocated by
means of rods and m and of an eccentric & which is rotated by a pulley i. In
this way the balls are continuously lifted by the slide to a height sufficient for
them to pass into the channel c.

page_text: This lifting device has no direct connection with the substance of the present
invention, as instead of the lifting device shown in the drawing any other suitable
construction may be used. The construction illustrated is to serve only as an
example of the manner in which the balls in the apparatus described can be
suitably transferred from the box into the channel c.
It will be understood that the block d which is represented in the drawing with
a flat upper surface may have any other suitable form, for instance it could be
replaced by a glass ball ground to a truly spherical shape.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is.-
1. An apparatus for testing the hardness or efficiency of steel or similar balls,
particularly of those used for ball bearings, characterised by a holder for the balls
having an inclined channel from which the balls to be tested fall on to a body
with a hard surface, such body being arranged opposite a vertically adjustable
slide in such manner that properly hardened balls rebounding to a certain height
pass over the slide into a receiver, wherens the useless or defective balls, in
CODsequence of their rebounding to a less height, do not reach said receiver, and
are thus separated from the good ones.
2. The combination and arrangement of parts forming an apparatus for testing
steel or similar balls, substantially as described and illustrated in the drawing.
Dated this 21st day of August 1896.
BOULT & WADE,
Agents for the Applicant.