Improvements in Changeable Gearing.
Year: 1896

page_text: Date of Application, 2nd Apr., 1896-Accepted, 27th June, 1896
COMPLETE SPECIFICATION.
Improvements in Changeable Gearing.
1, FRANK HOWARD LEFROY, of 160 West 84th Street, in the City of New
York, County of New York, and State of New York, United States of America,
Manufacturer, do hereby declare the nature of my invention in Changeable
Gearing, 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 improvement in gearing for crank actuated vehicles,
and it is embodied in the construction and arrangement of members hereinafter
referred to and definitely pointed out in the claims.
The invention is designed more particularly for application to bicycles and
tricycles, and is applicable to either the crank shaft or the shaft of the driving
wheel.
Primarily the invention is designed to afford a very positive and easy variation
of the leverage and consequently the speed of the driving chain or other power
transmitting instrumentality.
While I have suggested that the invention is applicable to certain classes of
vehicles, I wish it understood that it may be applied to other classes of machinery,
with equally as good results.
Heretofore it has been suggested to vary the speed of the driving means or chain
by shifting multiple gear of varying diameter, the gears being internal gears, and
consequently limiting the number of variations to the interior diameter of the
smallest gear, and in such constructions the multiple gears are of necessity loosely
mounted eccentrically, and are susceptible of disarrangement by the warping or
bending of their supports, thereby throwing their teeth out of true alignment with
the moving pinion.
These as well as other objections can be urged against structures employing
internal multiple gears. It has also been suggested in numerous places to employ
a shifting gear which may be employed eccentrically as well as concentric, but
which provides for but one change of speed. Such devices, are, however,
unsatisfactory owing to the limit of variation, and to the general complicated
arrangement of parts.
With my invention these objections are practically overcome.
In the drawings, wherein the preferred form of the invention is illustrated,
and in which like reference letters designate corresponding parts in the several
views,―
Figure 1 is a longitudinal vertical section taken through the crank shaft, and
sleeve of a bicycle.
Figure 2 is an elevation looking to the left hand of Figure 1, and showing the
shaft in section.
Figure 3 is a detail perspective of the shifting device.
.
In the drawings A designates the crank shaft, B the sleeve, and C the crank,
all of usual construction, with the exception that the shaft A has a longitudinal
spline b therein between the end of the sleeve and crank.
b
Slidingly supported on the shaft is the multo-gear D the same being prevented
from independent rotation by having a groove cut in its inner wall into which the
spline 6 passes. This gear D is composed of a stepped series of disks d d' d' each
having a diameter differing from the other arranged side by side and each being
formed with external teeth as shown. These gears constitute by preference an

page_text: integral unit, but it is to be understood that they can be otherwise formed or
constructed. The inner wall of gear D is recessed and a circumferential groove dª
is formed in the edge wall of this recess for purposes presently to be explained.
E designates the sprocket wheel which is in the form of a ring having the
sprocket teeth on its outer periphery and a series of gear teeth on its inner
peripheral wall. The diameter of the interior of the ring is substantially equal to
the diameter of the part d of the gear so that the latter will closely fit within the
former the teeth of the respective members intermeshing.
To independently support the sprocket ring I form a groove in its inner side face
and secure therein by suitable locking ring F the carrying frame C consisting
preferably of a ring having a flange fitting in the recess. Suitable balls may be
interposed if desired to form an antifriction bearing for the sprocket ring on the
frame. The carrying frame is fixedly held from rotation by being supported on
suitable arms 9 9 projecting outward from a sliding frame H and connected with
the carrying frame G at its bottom and sides only so that the upward movement of
the ring is unopposed by the arms.
The sliding frame H comprises the two curved side bars curved on a radii
with its center the center of the rear axle to prevent the binding of the chain by
the adjustments. These side bare are connected at their tops and bottoms by the
web and the cross-bar h³.
K designates the supporting plate keyed or in otherwise fixedly secured on the
end of the sleeve B. This plate is fashioned to conform to the shaft of the
frame H, but is somewhat smaller, its side edges being fitted in grooves * formed
in a flange on the side bars only of the frame H. By this means it will be
apparent that the frame H will have or be permitted a substantially vertical
movement on the supporting plate or at about right angles to the shaft, and by
its movement the sprocket ring will be raised or lowered as the case may be.
The flanges on the bars h h project laterally beyond the cross-bar and web,
so that the frame H is permitted a movement which will carry its opposite ends
beyond the plate K, the limit of movement being governed by the distance
between the cross-bar and web which, as will be readily understood can be greatly
varied without necessitating structural changes in the machine frame.
To effect the relative adjustment of the sprocket ring and gear I employ what I
term an adjusting cam L which consists of a flat plate 7 having a circular aperture
therein and sleeve the same loosely on the hub k of the fixed plate K, the same
being properly held in place by a suitable nut. The plate / has an arm or actuating
lever L' thereon which extends upward to any convenient point and by which the
same may be shifted or rotated about its axis. In the lower and side portions of
the plate is formed a cam path fashioned to correspond to the required vertical
movement of the sprocket ring. Into this cam path or groove is extended a
pin m made fast to the web à of the plate H so that as the plate is rotated the
plate H will be raised or lowered through the medium of the pin the pin working
in a slot in the plate K.
To provide for the movement of the gear D I form a squared hollow bushing
on the plate K and through this bushing passes a link M squared in cross section
and having a hook o at its outer end which loosely engages in the groove of the
gear D.
The opposite end of the link is turned down or hooked as at o' and passes into a
cam groove formed in a circular shaped flange concentrically mounted or formed
on the side of the plate 1 of the adjuster L.
By reference to the drawing it will be noted that the cams are so arranged
that while one serves to elevate the pin thereon the other being horizontal will
serve to move the link at right angles to the other. These cam grooves are so
shaped that the movement of the parts will be properly timed and when needed
the movement of the gear will be stopped and both movements interrupted or
locked by interrupted pitches in the cams.
It will be noted that the shifting device and the supporting frame H are both

page_text: arranged inwardly beyond the gear and are therefore located in a position to
prevent accidental interference and at the same time may be readily applied to the
usual structure without materially altering the parts.
In operation, by shifting the lever L the gear is moved longitudinally and as
its succeeding step reaches the plane of the sprocket ring the latter is lowered onto
the gear and the speed thereby varied. The movement is simple and effective.
By forming the bushing on the plate K the link M is held in its horizontal position
so that it is prevented from being cramped or bound in the groove d³.
While I have shown what I deem the preferable form of construction I wish it
understood that other forms may be employed so long as the principle of the
external gear is retained, which feature I regard as of much importance. I have.
shown but a three stepped gear for convenience but it will be evident that any
desired number may be used, ranging from two to ten or twenty. The gear
being supported directly on the axle is held positively irrespective of weight or
number.
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. In a gearing for crank actuated machines, the combination with a crank shaft
and a sleeve, of an externally toothed multo-gear loosely mounted on the shaft and
comprising a series of gears of varying diameters, means for preventing an
independent rotary movement of the gear, a vertically adjustable power transmitter
ring having a toothed inner wall, an adjustable frame supporting the ring, a fixed
support with which the frame slidingly engages, and shifting means for changing
the relative position of the gear and sprocket, substantially as described.
2. In a changeable gear for crank actuated machines, the combination with a
shaft, of a stepped multo-gear sleeved directly on the shaft and formed with
external teeth, ineans for preventing an independent rotation of the shaft and gear,
a power transmitting ring with which the gear engages, means for shifting the
ring at substantially a right angle to the gear, and means for changing the relative
lateral position between the gear and ring, substantially as described.
3. In a changeable gear for crank actuated machines, the combination with a
crank shaft and its sleeve, of a longitudinally movable multo-gear sleeved on the
shaft having external teeth, means for preventing independent rotation of the gear
and shaft, a plate fixed on the sleeve, a curved carrying frame slidingly supported
on the plate, arms on the frame, a power transmitting ring arranged to engage with
the gear, a loose connection between the ring and arms, a shifting cam mounted on
the sleeve having a plurality of cam paths therein, a sliding connection between the
cam and carrying frame, and a sliding connection between the cams and gear,
substantially as described.
4. In a changeable gear for crank actuated machines, the combination with a
crank shaft, of a stepped gear thereon having external teeth, a power transmitting
ring arranged to engage the gear, a movable support for the ring carried by the
crank sleeve, and a rotary shifter carried by the sleeve for changing the relative
position of the ring and gear, substantially as described.
5. In a changeable gear for crank actuated machines, the combination with a
crank shaft and its sleeve, of an externally toothed multo-gear on the shaft, a
power transmitting ring arranged to engage the gear, a curved carrying frame for
the ring comprising two side bars, laterally extending supporting arms, a plate
fixed to the sleeve and with which the frame slidingly engages, and a shifting
device mounted on the sleeve inwardly beyond the plate for changing the relative
position of the ring and gear, substantially as described.
6. In a changeable gear for crank actuated machines, the combination with a
crank shaft and its sleeve, of an externally toothed multo-gear, slidingly supported
on the shaft, means for preventing independent rotation of the gear and shaft, a
sprocket ring independent of the gear, having internal teeth arranged to engage

page_text: the gear, a carrying frame located inwardly beyond the gear, arms extending
outward from the frame and having a journal connection with the ring, a fixed
support for the frame with which the latter has a sliding connection, and a shifting
device having connections with the frame and gear and loosely sleeved on the frame,
substantially as described.
_7_La_a_changeable-gear-for-erank-actuated-machines, the combination with a
crank shaft and its sleeve, of a multo-gear on the shaft, a power transmitting ring
arranged to engage the gear, means for adjustably supporting the ring directly on
the sleeve, a rotatable shifting device having horizontal and vertical cam grooves
therein and connections engaging the grooves for changing the relative positions of
the gear and ring, substantially as described.
8. In a changeable gear for crank actuated machines, the combination with a
shaft, of a multo-gear on the shaft, a sprocket ring independent of the gear, a ring
supporting the sprocket ring loosely engaging therewith, a curved carrying frame
for the supporting ring located inward from the ring, arms connecting the carrying
frame and supporting ring, a fixed support for the carrying frame, a cam plate
having loose connection with the carrying frame and gear, and comprising a
horizontal plate and a vertical plate having cams thereon and a lever for shifting
the plates, and means operated by the cams for shifting the gears and ring,
substantially as described."
9. In a changeable gear for crank actuated machines, the combination with the
shaft, of an external multo-gear loosely mounted to move longitudinally on the
shaft, a power transmitting ring arranged to be engaged with the gear and movable
in a vertical plane only, and means for changing the relative position of the ring
and gear, so that the ring will be caused to engage the different steps or sections of
the gear, substantially as described.
Dated this 2nd day of Annil 1806