Improvements in Keys and Feathers for Holding Wheels, Pulleys, and the like on their Shafts
Year: 1888

page_text: Date of Application, 12th Dec., 1888
Complete Specification Left, 12th Sept., 1889-Accepted, 9th Nov., 1889
PROVISIONAL SPECIFICATION.
Improvements in Keys and Feathers for Holding Wheels, Pulleys,
and the like on their Shafts.
I, JULIUS ROEMMELE, of Freiburg, in the Grand-Duchy of Baden, Germany,
Engineer and Manufacturer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to keys and feathers such as are used for keying or holding
pulleys upon shafts, and its object is to facilitate the operation of fitting the key or
feather to its way in both pulley and shaft.
In carrying the invention into effect, I reduce the fitting surface of the key or
feather by forming grooves along the bearing surfaces so that only the remaining,
i.e., the projecting, surfaces of the key or feather needs to be fitted.
Such grooved keys and feathers offer more resistance to torsion in proportion to
their cross-section, than the keys hitherto employed, because their bearing surface is
placed where theoretically it ought to be.
000
JULIUS ROEMMELE.
COMPLETE SPECIFICATION.
Improvements in Keys and Feathers for Holding Wheels, Pulleys,
and the like on their Shafts.
I, JULIUS ROEMMELE, of Freiburg, in the Grand Duchy of Baden, Germany,
Engineer, 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 keys and feathers such as are used for keying or holding
pulleys upon shafts, and its object is to facilitate the operation of fitting the key or
feather to its way in both pulley and shaft.
In carrying the invention into effect, I reduce the fitting surface of the key, or
feather, by forming grooves along the bearing surfaces, so that only the remaining,
i.e., the projecting, surfaces of the key, or feather, need to be fitted.
Such grooved keys and feathers offer more resistance to torsion in proportion to
their cross-section, than the keys hitherto employed, because their bearing surface is
placed where theoretically it ought to be.
In order that my invention, and the means by which the same is to be carried into
practical effect, may be thoroughly understood; I will now describe them in detail
referring in so doing to the accompanying drawing which is to be taken as part of this
specification and read therewith.
Fig. 1 a, b and c are, respectively, a side elevation, plan, and cross section of my
improved feather provided with grooves; and Fig. 1 c¹ a cross section of a key with
rectangular recesses. Fig. 2 a and b are, respectively, side elevation and cross section
of an improved key, one bearing-surface of which is formed to fit upon the axle.
Fig. 3 a, b and c are respectively side elevation, plan, and cross section of my improved
key as adapted to secure wheels, pulleys and the like upon their shafts; and Figs. 4
and 5 are the end views of two shafts, partly in section, illustrating the different
applications of my invention.
As will be understood from the drawing, the grooves above mentioned considerably
reduce the fitting surfaces of the key or feather so as to enable the workman fitting
it to produce more easily with his file a plane surface, inasmuch as he has only to fit
about half of the usual bearing surface.

page_text: Supposing a wheel, pulley or the like to be fixed upon a shaft A (Fig. 4) and turned
in the direction of the arrow I, the shaft being turned in the opposite direction, i.e., in
the direction of arrow II, the originally parallel surfaces o p and q r, respectively,
will be inclined to diverge so as to form an angle, as represented by dotted lines o' p¹
and q; and this shews that the key is exposed to a crushing strain at o q.
That part of the fitting surface of a key which lies nearest to the centre-line xx
will be exposed to the least strain, so that the material of the key may be cut away
in the form of the grooves without lessening its strength. Hitherto a very skilled
workman has been required to fit a key, so as to prevent its rocking over the points st;
whilst by means of this grooved key all difficulty relating to the true fitting of the
key is entirely obviated.
In cases where the key is exposed to an extraordinary strain the seat may be cut
so as to allow the material of the wheel, or the like, and of the shaft to fill up the
grooves or recesses of the key (Fig. 5); and this arrangement will give the greatest
possible resistance to the shearing strain without in the least weakening the boss of
the wheel.
The form of the key (Figs. 2 and 5 B) is adapted to secure the wheel, pulley, etc.,
on the shaft by friction only, a method applicable in light machinery running at high
speeds.
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 :
A key, or feather, for holding wheels, pulleys and the like on their shafts having
grooves or recesses for diminishing the fitting surfaces substantially as and for the
purpose specified.
Dated this 12th day of September 1889.
PHILLIPS & LEIGH,
No. 22, Southampton Buildings, Chancery Lane, W.C., Agents for the Applicant.