Improvements in or relating to Belt Driving Gear.
Year: 1898

page_text: Date of Application, 25th Apr., 1898-Accepted, 19th Nov., 1898
COMPLETE SPECIFICATION.
Improvements in or relating to Belt Driving Gear.
I, AMÉDÉE BOLLÉE (Pére), of Le Mans, France, 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:-
The object of this invention is, with a driving shaft rotating at a given speed,
and a driven shaft, to obtain by means of a belt, metallic or otherwise.
1. Changes of speed of the driven shaft.
2. The slackening of the belt when it has no useful work to perform.
3. The avoidance of friction of loose pulleys.
4. Absolute rest, without loss of power, of the belt when it has no work to do.
I will describe, by way of example, a driving gear, particularly applicable to
motor vehicles in which a single belt fulfils all these requirements.
I construct a cone made, say for three different speeds and consisting of four
steps or diameters G1, G2, G3, G+, secured to the driving shaft A, and also a cone
mounted on the driven shaft B and consisting of alternating fast (F1 F2 F³) and
loose (M1 M2 M3 M) stepped pulleys (Fig. 1).
move
Two coupling forks are employed one turned upwards and the other down-
wards, each constituted by two branches forming a V having arms not in the same
vertical plane, the branches 6 and e nearest to the wider end of the cones being
nearer the cones than the other branches a and d. These two V-shaped forks
are moreover constituted or connected in such manner that they can
together, both in vertical and in horizontal planes, along lines, substantially
parallel to X Y and UV. The fork a, b moving along an oblique line indicated
in plan and elevation in Figs. 1 & 2 by the line, y; the fork e d moving in a
similar oblique line (Fig. 1 in plan) the elevation not being shown as it is
similar to ry Fig. 2.
It is sufficient for each fork to form in the plane normal to the belt a V, which
may be of any suitable material and may be formed if desired by cylindrical or
conical rollers or simply by two oblique surfaces meeting together inclined rela-
tively to each other, so as to transfer the V that they form by their intersection
along a line parallel to X Y, U V.
Assuming that the belt is on G2 F2 by pushing the forks towards the left, the
belt is brought at one end on to the loose, pulley M and against the next step,
and at the other end it overlaps G² G³. As the branch b of the fork is nearer
the cone G than the branch to the cone M2 the branch b will at once cause
the belt to fall on G3 while the belt which will thus become inclined at the
other end will not immediately be forced to move on to the larger diameter of M³
as the branch is sufficiently far away. By continuing to push the forks to-
wards the left, the branch will finally force the belt on to the larger part of M².
By continuing the movement, the belt afterwards passes, without any resistance,
off the loose pulley M to the fixed pulley F3 which is of the same diameter, and
the speed of the driven shaft will consequently be changed. If the belt is
pushed still further towards the left, it comes first on the loose pulley M³ whereby

page_text: the rotation of the cone is stopped, and then continuing, it falls on the step G4
of one cone and the loose pulley M of the other.
Then not only the shaft B is completely stopped, but also the belt is released
and its tension is considerably reduced.
By moving the belt towards the right, it is caused to pass simultaneously on
to G & M and to become stretched, and is then ready to be moved on to the
fixed pulley F3, for driving purposes.
I obtain in this way an absolute slackening of my belt when it has no work
to perform, and its, immediate stretching as soon as it is required to work.
But the general arrangement forming the subject of this invention, gives
still better results in applying to the driving pulley. the arrangement of loose
pulleys of the driven pulley.
In this arrangement I provide at the end of the driving cone (Fig. 4) a stepped
pulley G4 loose externally on a bearing in which rotates the driving shaft A.
The loose pulley G can be applied laterally. against the fixed part G3 which
then causes it to participate in the rotation by frictional adhesion which can be
increased either by a strong weight or by a conical surface of leather, rubber or
by a magnetic coupling, stops, clutch or equivalent means.
The small step-M* of the driven shaft loose pulleys, M3 M4 is mounted in the
same manner, it being loose externally on the bearing of the shaft B while the
other step M³ is loose either on the same bearing or on the shaft B itself.
Assuming that the belt is on GM, it being thus on two loose pulleys, the
spindles of which do not rotate, as they are constituted by the bearings of
the shaft, will not move; and the shaft A- will continue to rotate indefinitely
without the belt receiving any power or the pulleys requiring the slightest lubri-
cation, as all these parts are stationary.
By pushing the belt towards the right, it forces the loose pulley G+ against G³
simply by frictional engagement or it will effect this movement more certainly
if it is provided with a flange, which without being indispensable, facilitates the
engagement of G4 and G.
The contact between G³ and G4 being produced, the pulley G rotates as if
it were in one piece with G³, and the belt passes freely from G' on to G³ and
from Mon to M³ and becomes stretched. Afterwards its working is the same
as already described.
By moving the branches a and d away from the cones to a greater or less ex-
tent, the interval between the moment when the branches b and c of the forks
cause the belt to be moved and the moment when the other branches a and d
come into operation can be regulated with great exactitude. This regulating
can be effected by inclining the branches of the forks.
The disengaging forks must be arranged so that the axis of the belt passes
exactly through the bisecting line of the forks when said belt is operative and
in place.
The wider the steps are relatively to the width of the belt, the more can the
branches of the disengaging forks be opposite each other in a vertical plane,
that is to say, the more they can approach the form of a flat V.
On the contrary, if the distance between the two shafts is very small, the belt
very wide and the loose pulleys comparatively thin disces, a supplementary means
may be found useful for assisting the forks to cause the belt to fall at one end
before raising it at the other end. It is sufficient in this case to connect the two
shafts in such manner, say by an oscillating lever l', as to enable each cone
to be moved longitudinally in the direction indicated by the arrows (Fig. 3)
before moving the forks.
The cones are thus moved to a desired extent so that only half the width of
the belt engage with the cones. By then moving the forks, the belt falls at
once in the desired manner as it was supported only on half its width.
The general arrangement may be modified in many ways. Thus the length
of the cones can be limited to a single step for working and one step for slacken-

page_text: ing, and as many pairs of such cones can be used, as speeds required, all the
non-operative belts being slackened, in the manner described, and remain
stationary without any friction during the working of the operative, belt.
It is necessary theoretically, in order that a belt may rise well from one step
to another, that it should rest during its passage only on loose pulleys. As each
fast pulley may become a loose one, if disengaged from its shaft, driven cones
consisting of alternate fast and loose pulleys may be replaced by cones made in
one piece (Fig. 3) which may become a single loose pulley by disengaging a
suitable coupling, say a conical one as G. This disengaging may for instance,
be effected by the longitudinal movement of the cones produced by the lever P.
The driving cone, provided that it is also fitted with a suitable coupling, may
also be in one piece with the loose pulley G (Fig. 4), the belt being stationary
when it has no work to perform. The two cones may in this case be mounted
loosely at their ends on bearings supporting the shafts A and B, similarly to the
pulley G on the bearing O.
The loose pulleys G and M may be mounted on fixed shafts secured in line
with the rotating shafts A and
B.
If the distance between the shafts A and B is a variable one or if there is a
loose or jockey pulley on the belt or an analogous device, only one cone need be
a stepped one.
The surface of, the loose pulleys or discs may be a conical one to facilitate the
movement of the belt.
The surface of the loose pulleys or discs and the surface of the stepped cones
may be provided with rubber c (Fig. 5) or similar substances or with grooves
preferably of spiral shape, or other means of producing, a greater frictional engage-
ment between the pulley and belt.
Only one of the two cones A or B may have the difference in diameters for
stretching the belt.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is:-
1. In a belt or like driving gear the general hereinbefore described arrange-
ment whereby, the belt remains stationary and slack when it has no useful work
to perform whilst the driving shaft rotates.
2. The arrangement hereinbefore described for avoiding the friction of loose
pulleys.
3. The means substantially as described for causing the belt to pass from a
position of rest to its operative position.
4. For the purpose of stretching and slackening the belt the employment of
pulleys of different diameters on the driving shaft substantially as described.
5. The arrangement of loose stepped pulleys or of two unequal-diameter loose
pulleys side by side on the driven shaft for the purpose of stretching the belt
substantially as described.
6. The arrangement of loose stepped pulleys or discs substantially as herein-
before described, for facilitating the passage of the belt from a pulley of one
diameter to a pulley of a different diameter.
7. The arrangement of two stepped cones, movable longitudinally relatively
to belt shifting forks substantially as and for the purpose described.
8. A conical pulley construction of the character described movable longi-
tudinally for the purpose of disengaging it from its shaft.
9. Means whereby the driven cone becomes loose on its shaft at the moment
the belt changes from one step to another, substantially as described.
10. A stepped cone or loose discs or pulleys provided on the sides of the steps
with asperities or grooves preferably of spiral form or with rubber or similar
material substantially as described.
11. A conical pulley consisting of alternate fast and loose pulleys.

page_text: 12. The arrangement substantially as described, of disengaging forks of V shape
for inclining the belt at one end, in order to facilitate the rise or fall from one
step of a pulley to another.
13. The arrangement substantially as described, of disengaging forks with
their branches unequally distant from the pulleys, in order to cause one end of
the belt to fall before the other moves on to the next step of the pulley substan-
tially as described.
14. The application to motor vehicles of belt transmission gearing substan-
tially as described.
15. Belt transmission gearing substantially as described and illustrated in
Figures 1 and 2 or in Figure 3 of the accompanying drawings.
16. In belt transmission gearing of the character described, a loose pulley G
adapted to be moved longitudinally against the fixed pulley G³ substantially as
described and illustrated in Figure 4 of the accompanying drawings.
Dated this 25th day of April 1908.
BOULT & WADE,
Agents for the Applicant.
BOULT & WADE,
Agents for the Applicant.