Improvements in "Bottom Brackets" for Cycles.
Year: 1897

page_text: Date of Application, 7th Oct., 1897
Improvements in "Bottom Brackets" for Cycles.
I, GEORGE GATTON MELHUISHI HARDINGHAM, of 191, Fleet Street, in the City of
London, Civil Engineer and Chartered Patent Agent, do hereby declare the nature
of this invention (a communication from The Attila-Fahrrad-Werke, Aktien-
Gesellschaft, vormals, E. Kretzschmar & Company, of Dresden-Lobsan, in the
Kingdom of Saxony) to be as follows:-
'
This invention relates to an improved construction or arrangement of crank
shaft bearing for cycles, commonly known as the 'bottom bracket.'
In cycles as ordinarily constructed, such, for example, as those of the Humber
type, the spindle which carries the cranks is supported in a cylinder, provided
on the exterior with sockets for receiving certain portions of the frame; the interior
of the said cylinder being suitably formed for the reception of the cups, which,
in conjunction with the cones on the spindle constitute the ball-races. One of the
inconveniences incidental to this method of construction is that the cylinder has
to be completely finished for the reception of the several parts of the bearing,
before it is joined to the frame, the process of brazing to the frame frequently
resulting in the distortion of the screw-threads and necessitating their having to
be re-cut. Moreover, the location of the balls between the cones on the axle and
the cups results in a strain diagonal to the main axis, which is objectionable.
Vertical pressure in the bearing is efficiently provided for in the well-known
Eolus' type of bearing, and the principle therein employed is adopted in the
arrangement hereinafter described.
The cylinder is bored true for the reception of the parts of a separately fitted
bearing, and of the crank-spindle. This enables the cylinder sockets to be brazed
or otherwise connected with the corresponding parts of the frame before fitting
any of the parts of the bearing therein, or before any provision is made to adapt
it for the reception of those parts.
The crank-spindle, is furnished, near the chain-wheel and one of the cranks
with a collar formed with a groove in its periphery. Over the collar is fitted a
socket or sleeve having a concave inner surface. Into this socket is screwed a
covering plate, the inner face of which is concave; the two concave surfaces being,
opposed to each other and forming, with the groove on the collar, the ball-race.
The socket extends into the cylinder, and into the extension is screwed a short
central tube. Near the other end, the crank-spindle is provided with a stud
or pin; a loose collar, having a longitudinal slot formed at its inner end, being
passed on the spindle.
Another socket similar to that previously described is then screwed on the
other end of the short tube; the extension on the socket entering the bore of the
cylinder, whilst a covering plate is screwed into the outer end of the socket. The
loose collar is provided with a circular groove, similar to that in the fast collar,
and is retained within the socket or sleeve by the balls of the bearing.
This loose collar or ring is capable of rotation with the spindle by means of

page_text: the stud on the latter engaging with the slot in the collar; the said collar being
also capable of longitudinal movement along the spindle in order to effect, the
necessary adjustment of the parts. The socket having been screwed sufficiently
far on the central tube to effect a tight junction with the cylinder, the remaining
crank may be applied to the spindle.
By the employment of the improved bottom-bracket, the independent construc-
tion of the frame, and of the spindle and its bearings, is made practicable; the
necessary adjustment to compensate for wear, or the removing and exchanging
of any of the parts of the bearing being accomplished without interfering with
the construction of the machine itself.
Dated this 6th day of October 1897
I, GEORGE GATTON MELHUISH HARDINGHAM, of 191, Fleet Street, in the City of
London, Civil Engineer and Chartered Patent Agent, do hereby declare the nature
of this invention (a communication from The Atilla-Fahrrad-Werke, Aktien-
Gesellschaft, vormals E. Kretzschmar & Company, of Dresden-Lobsan, in the
Kingdom of Saxony); 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 an improved construction or arrangement of crank-
shaft bearing for cycles commonly known as the 'bottom-bracket.'
In cycles as ordinarily constructed, such, for example, as those of the Humber
type, the spindle which carries the cranks is supported in a cylindrical casing,
provided on the exterior with radial sockets for receiving certain portions of the
frame; the interior of the cylinder being suitably formed for the reception of the
cups, which, in conjunction with the cones on the spindle constitute the ball-races.
One of the inconveniences incidental to this method of construction is that the
cylinder has to be completely finished for the reception of the several parts of the
bearing before it is joined to the frame, the process of brazing to the frame
frequently resulting in the distortion of the screw-threads and necessitating their
having to be re-cut. Moreover, the location of the balls between the cones on the
axle and the cups results in a strain diagonal to the main axis, which is objection-
able.
Vertical pressure in the bearing is efficiently provided for in the well-known
'Eolus' type of bearing, and the principle therein employed is adopted in the
arrangement hereinafter described.
In the accompanying drawings, Fig. 1 is a longitudinal section of one end of
the improved crank-shaft bearing detached from the cylindrical casing of the
frame; Fig. 2 being a similar view of the cylindrical bearing fitted in the said
casing.
In a 'bottom bracket' or bearing constructed according to the present inven-
tion, the cylinder is bored true for the reception of the parts of a separately fitted
bearing, and of the crank-spindle. This enables the sockets on the cylinder to
be brazed or otherwise connected with the corresponding parts of the frame before
fitting any of the parts of the bearing therein, or before any provision is made to
adapt it for the reception of those parts
Referring to the drawings, the crank-spindle a, is furnished, near the chain-
wheel and one of the cranks 7 with a collar b formed with an annular groove c.

page_text: a
Over the collar 6 is fitted a socket or sleeve e having a concave inner surface which
may be formed by inserting a screwed ring el. Into the socket e is screwed the
closing ring or plate g, the inner face of such plate being concave. The two con-
cave surfaces being opposed to each other form in conjunction with the groove c
the ball-race. The socket e extends into the cylinder, and into the extended por-
tion h is screwed a short central tube i whereof the screwed portions are tapped in
the same direction. The chain-wheel and crank / having been secured to the
axle the fitting as shewn in Fig. 1 is inserted in the bore of the cylinder. Near
the opposite extremity, the crank-spindle a is provided with a stud or pin d;
loose collar o, having a longitudinal slot o¹ formed at its inner end, being passed
on the spindle a. Another socket m having a concave inner face or fitted with a
ring m¹ similar to that previously described is then screwed on the other end of the
short tube ; the extension on the socket entering the bore of the cylinder, whilst
a covering ring or plate g is screwed into the outer end of the socket. The loose
collar o is provided with an annular groove n, similar to that in the fast collar b,
and is retained within the socket or sleeve by the balls of the bearings. This loose
collar or ring o is capable of rotation with the spindle a by means of the stud d
on the latter engaging in the slot o' in the collar; the latter being also capable
of longitudinal movement along the spindle in order to effect the necessary adjust-
ment of the parts. The socket m having been screwed sufficiently far on the
central tube i to effect a tight junction with the cylinder q, the remaining crank p
may be applied to the spindle.
By the employment of the above described bottom-bracket, the independent con-
struction of the frame and of the spindle and its bearings is made practicable;
the necessary adjustment to compensate for wear, and the removing and exchang-
ing of any of the parts of the bearing being accomplished without interfering
with the construction of the machine itself.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I claim :-
1. In a crank-shaft bearing or 'bottom bracket' for cycles wherein ball bearings
are arranged within sockets connected by a central tube so as to be inserted into
the cylindrical casing of the frame, the herein described means for effecting the
adjustment of the parts of the bearing before fitting same in the frame, and for
obviating any displacement of the parts while adjusting the axle within the cylin-
drical casing of the frame; same comprising collars b, o, sockets e e¹, m m³, central
tube and closing rings g g, substantially as set forth.
2. In a crank-shaft bearing or 'bottom bracket' for cycles of the character
referred to in the preceding claiming clause, the employment of a loose collar o
having a ball-race formed in its outer surface and a slot at its inner end for engag-
ing with a pin on the axle in conjunction with a socket m and concave rings m³, g,
substantially as and for the purposes specified.
6
3. A crank-shaft bearing or bottom bracket' for cycles constructed or operating
substantially as described with reference to the accompanying drawings.
1000
G. G. M. HARDINGHAM.