Spur-wheels, Specially Applicable to Velocipedes.
Year: 1885

page_text: Spur-wheels, Specially Applicable to Velocipedes.
I, JOHN SHARP of 19 Bath Street Birmingham in the County of Warwick
Mechanician do liéreby declare the nature of my invention for IMPROVEMENTS IN
THE CONSTRUCTION AND MANUFACTURE OF CHAIN OR SPUR-WHEELS SPECIALLY
APPLICABLE TO VELOCIPEDES to be as follows:
My said invention relates chiefly to those spur-wheels which are connected by
means of chains and which are used to drive velocipedes. The object of the said
invention is to produce spur-wheels in such a form as to combine in a much higher.
degree than is now usual-strength, symmetry, and lightness. For this purpose
I construct the said spur wheels with a circumscribing marginal flange on each side.
These said circumscribing marginal flanges conform evenly to the contour and con-
figuration of the circumscribing peripheral line formed by the teeth and the
bottoms of the intervening spaces between them, and therefore they are identical
with and form an integral part of the said teeth and spaces. This peripheral
portion of the wheel is connected with a central boss either by a thin plain web
or disc or by radial straight or curved arms, and the part of the web.at the base of
the teeth is perforated in a suitable manner to give lightness and symmetry.
These said spur-wheels are by preference cast from patterns which I construct in
a special manner as follows: Having cut the teeth of the wheels in the ordinary
way, I fix the wheel on a stud mandrel in a lathe having the ordinary means for
providing divisions and in the compound slide-rest I fix the apparatus for cutting
away the surplus material of the various forms required-by means of circular
cutters termed drills. The said apparatus consists of a boss having a large hole, and
a cylindrical piece nicely fitted therein, in which there is a hole bored through-
parallel with but eccentric to its centre In this hole is nicely fitted a spindle.
having on one end a head to hold the drills and. on the other end a pulley to drive
the spindle. On the outer periphery of the large cylindrical piece is a tangent
wheel and a worm in gear there with ;-so that the slide-rest advances the drill to a:
stop-depth, and by means of the worm and tangent wheel the revolving drill is
made to move in an eccentric direction as indicated by the shape of the tooth and
space of the wheel,

page_text: f
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Improvements in the Construction and Manufacture of Chain or
Spur Wheels, Specially Applicable to Velooipedes.
I, JOHN SHARP of 19 Bath Street Birmingham in the County of Warwick
Mechanician do hereby declare the nature of my invention for IMPROVEMENTS IN
THE CONSTRUCTION AND MANUFACTURE OF CHAIN OR SPUR WHEELS SPECIALLY
APPLICABLE TO VELOCIPEDES and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement:
My said invention relates chiefly to those spur wheels which are connected by
means of chains and which are used to drive velocipedes, but they are also
applicable wherever such wheels are required.
The object of the said invention is to produce spur wheels so as to combine-in
a much higher degree than is now usual-strength, symmetry and lightness. For
this purpose I construct the said spur wheels with a circumscribing peripheral
marginal flange on each side of each wheel. These said circumscribing marginal
flanges conform evenly-or nearly so-to the contour and configuration of the
circumscribing' peripheral line formed by the teeth and the bottoms of the inter-
vening spaces and therefore they are identical with, and, form an integral part of
the said teeth and spaces.
This peripheral portion of the wheel is connected with a central boss either by a
thin plain web or disc, or by radial straight or curved arms, and the part of the
disc at the base of the teeth may be perforated in a suitable manner for the
purpose of lightness and symmetry.
The said chain or spur wheels are, by preference, cast from patterns.
I will now describe with reference to the accompanying drawings the manner in
which my invention is to be performed; Figures 1, 3 and 5 illustrate side elevations,
and Figures 2, 4 and 6 sectional edge views through the centre of Figures 1, 3 and 5
respectively of chain or spur wheels constructed according to my invention.
The same letters of reference in the various figures refer to the same parts.
A is the circumscribing peripheral flange forming an integral part of the teeth B
and of the bottoms of the intervening spaces; and D shews where the superfluous
material has been removed from the rim of the wheel.
The ordinary chain or spur wheel contains a circular rim which is concentric
with its axis, and on which the teeth are formed-so that each tooth contains a
considerable amount of material that is not necessary.
Now according to my said invention a portion of each tooth B and of the rim
under each tooth is, cut away as represented in the space marked D in the plate
wheel-Figure 1, in the wheel with straight radial arms-Figure 3, and in the
wheel with curved arms,-Figure 5 ;-thus leaving the under surface of the pro-
jecting flange A of the same thickness-or nearly so all round the wheel, and of

page_text: nearly the same configuration as the circumscribing peripheral line formed by the
teeth B and the bottoms of the spaces C.
Having particularly described and ascertained the nature of my said invention
for "Improvements in the construction and manufacture of chain or spur wheels
specially applicable to velocipedes," and in what manner the same is to be performed
I declare that what I claim is :-
The construction and manufacture of chain or spur wheels having circumscribing
peripheral flanges substantially as hereinbefore described and illustrated in the
accompanying drawinga