An Improvement in a Bicycle Frame known as the Diamond Frame.
Year: 1896

page_text: Date of Application, 4th Jan., 1896
Complete Specification Left, 10th June, 1896-Accepted, 1st Aug., 1896
PROVISIONAL SPECIFICATION.
An Improvement in a Bicycle Frame known as the Diamond
Frame.
HENRY LEEMING 51 Bland Street Moss Side Manchester Bicycle Mechanic
do hereby declare the nature of this invention to be as follows:-
An improvement in a bicycle frame known as a diamond frame by brazing the
back wheel bottom quadrents or stays on to the seat pillar tube instead of the
crank bracket as at present brazed thus securing a much narrower tread and
stronger back wheel and frame.
January 3rd 1896
An Improvement in a Bicycle Frame known as the Diamond
Frame.
I, HENRY LEEMING of 51 Bland Street, Moss Side, Manchester in the County
of Lancaster, 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 what is known as the diamond frame of bicycles and
consists in the improved construction of the frame and has for its object to obviate
or reduce the springing of the frame in a direction or directions detrimental to
the progress of the machine and at the same time provide the minimum width
of tread.
Hitherto what is kuown as the diamond frame consisted of a tubular structure
which in side clevation consisted of two triangles or a triangle and a four sided
polygon having a common base which coincided with the seat pillar tube or tubes.
The adjacent angles of the two figures also coincided or nearly so. At the angles
at the upper part of the frame was the seat pin socket or clip, and at the angles at
the lower part of the frame there was set the bottom bracket or crank axle bearing.
The objections to this form of structure are two fold, first on account of the great
stiffness of that part of the frame behind the crank axle the pressure of the foot
upon the pedal in a forward direction produced a downward bending of the fore
part of the frame which tended to increase the distance of the wheels apart and it
was found that this impeded that progress of the machine which would otherwise
be obtained; and second, owing to the necessity for obtaining a narrow tread on
the pedals the bottom stays forming a fork had to be set so close together at their
junction with the bottom bracket or crank bearing for the purpose of allowing
sufficient clearance for the gearing that the transverse stiffness of the frame was
weak and when great pressure was applied to the pedals the frame twisted and
threw the wheels out of line.
I obviate these defects by arranging stays connecting the rear axle bearings with
the seat pillar tube or tubes, above the centre of the crank axle where I obtain

page_text: greater transverse width, and preferably above the rim of the chain wheel.
prefer also to continue the said stays beyond the seat pillar tube or tubes and
connect them or their continuation to the lower tube or side of the front part of
the frame, by which a lighter bottom tube or side may be safely used.
The said stays and continuation thereof may be connected to the seat pillar tube
or tubes and to the lower tube aforesaid by brazing or by clips.
This improved construction permits, when pressure is applied to the pedals, the
whole framework to spring in such a manner that the wheels have a tendency
to draw closer together which I affirm does not check the progress of the
machine.
The drawings attached hereunto illustrate a frame constructed on the diamond
principle and my improvement applied thereto.
Figure 1 represents a side elevation of the improved frame, and Figure 2 a plan
of the same looking from the top.
The frame consists of the seat pillar tube a shewing socket tube b, top tube c,
bottom tube d, back stays e e, arranged as usual, and the stays ff...
I fix the stays f, to the seat pillar tube d, above the bottom bracket or crank
axle bearings, preferably above the chain wheel p. The continuations f¹ of the
said stays are shewn fixed to the lower tube d of the front part of the frame.
Without this continuation the object of this improved construction is attained but
I obtain increased stiffness thereby and I may employ a lighter tube d. The dotted
lines indicate the position of the bottom stays or fork in diamond frame bicycles
hitherto made.
Having now particularly described and ascertained the nature of this said
invention and in what manner the same is to be performed I declare that what
I claim is:
First. The improved construction of bicycle frame substantially as and for the
purpose described and illustrated herein before and in and by the accompanying
drawings.
Second. In "diamond" bicycle frames connecting the rear axle bearings to the
seat pillar tube or its equivalent above the chain gear wheel of the crank axle by
the stays substantially as and for the purpose described and illustrated
herein before and in and by the accompanying drawings.
Dated this 9th day of June 1896.
R. J. URQUHART,
57, Barton Arcade, Manchester, and 5, Clayton Square, Liverpool,
Consulting Engineer and Patent Agent.