Improvements in Frictional Gearing.
Year: 1889

page_text: Date of Application, 9th Apr.; 1889-Accepted, 20th July, 1889
COMPLETE SPECIFICATION.
Improvements in Frictional Gearing.
I, GEORGE FRANK EVANS of Somerville, County of Middlesex, State of
Massachusetts, United States of America Mechanic, 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 Frictional Gearing and consists primarily in the employ-
ment of an endless belt, which loosely encircles one of two operating gears, the
peripheries of the latter not being in contact, but sufficiently near together to grip
the endless band, which passes between them. Furthermore this invention relates to
an application of mino No. 15651 dated Octr. 30th 1888, in which is described
mechanism for operating two parallel shafts by means of straight faced frictional
gears and a loose endless band.
The object of my present invention is to provide mechanism with which to operate,
by means of frictional gearing, so called, two shafts which are not parallel. This
gearing consists of two bevel friction gears, not in contact, which grip an endless
belt, loosely encircling one of said gears and adapted to pass between the two gears.
The drawings, herewith annexed, represent in Fig. 1 frictional gearing which
embodies my invention, showing two co-operating shafts at right angles. Fig. 2 is a
modification in which a flange is formed upon one of the bevel friction gears. Fig. 3
is a plan and Fig. 4 a vertical section, diametrically of two gears, showing mechanism
by which the motion of the driven shaft can be reversed. Fig. 5 is a plan of two
shafts obliquely positioned. Fig. 6 represents in elevation mechanism for causing
the driven gear to approach or retreat from the continuously rotary driving gear.
Fig. 7 is a plan of the same with the driven gear represented only in broken lines to
more clearly show said mechanism.
The principle of frictional gearing in connection with a continuous band, which
loosely encircles one of the frictional gears, has been fully explained in my previous
invention before referred to; hence it will be unnecessary to repeat such explanation
in the present application. The gist of my invention is embodied in the arrangement
of parts by which I am enabled to operate two shafts not parallel, but at right angles
or inclined at any angle desired. The advantages thus obtained are apparent.
In the drawings, see Fig. 1, I have shown two shafts, the driver at 2, the driven,
or actuated one, at 3. Upon their adjacent ends are affixed two frictional gears 4, 5,
respectively. In the present instance said gears are miter gears and the shafts at
right, angles. About the gear 5 on the driven shaft is placed an endless band or
belt 6, which loosely encircles the latter and passes between the two gears by which it
is gripped. To start and stop the driven shaft, as occasion requires, the latter is
adapted to have end wise movement, which may be produced by any suitable
mechanism, and thus the frictional gear may be caused to approach or retreat from
the co-operating gear 4, and thus by producing pressure upon the band, or removing
it entirely therefrom, cause the shaft 3 to start or stop.
In Figs. 6 and 7 I have shown mechanism for operating the driven gear 5, in
order to cause it to approach the driving gear 4 and thereby produce sufficient
pressure between the gears to grip the belt, and cause activity in said gear 5, or, by
causing said gear 5 to retreat from its co-operating gear, reduce the pressure and
permit the driven gear to become stationary, as occasion may require. There are
many mechanical expedients, which will suggest themselves to those skilled in the art,
but the parts shown in said Figs. 6 and 7 will suffice to illustrate one way in which
this result can be accomplished.
In said drawings the driving shaft 2 and its gear 4 is presumed to have continuous
rotary movement. To cause the shaft 3 with gear 5 to start or become active, the
bearing or box is provided with a stationary cam-faced hub 16, which contacts with a

page_text: similar but oppositely arranged hub 17 loosely mounted upon the shaft 3, the gear 5
resting upon said hub 17. Said gear 5 is free to move endwise of its shaft upon a
spline 18, by which connection the shaft and gear are compelled to rotate in unison.
Further affixed upon the loose hub 17 is a spirally toothed wheel 19 adapted to
engage a worm 2,.which is niounted upon a shaft 21, suitably journaled and con-
trolled by a hand wheel 23. By movement of the shaft 21, and its worm the whoel 19
is given a partial revolution and by means of the loose cam-faced hub 17 bearing
against the stationary hub 16, the gear 5 is forcibly pressed towards the driving gear,
or caused to withdraw therefrom: moving end wise of the shaft. Hence the counter
or driven shaft may be rendered active or inactive and the pressure upon the belt
adjusted during its rotation.
In the above instance the bevel gear is shown, as having endwise movement upon
the shaft, but in lieu thereof it is evident that said gear may be fast upon the shaft
and mechanism applied to the shaft to actuate the latter and thereby produce proper
pressure upon the belt, or remove it therefrom.
In Fig. 2, is shown a modification of the above mechanism in which the actuated
gear is provided with a flange or rim 7, and in instances, where heavy work is to
be done prevents accidental crowding of the belt to the high side of the frictional
gears.
Fig. 5, illustrates the advantages of my invention to shafts which are obliquely
disposed. As before explained, 2 is the actuating, 3 the actnated shaft furnished with
bevel frictional gears 8, 9; between the later operates the endless band 6, which
loosely encircles the gear 9. It is evident that by simply changing the hovels of
the two gears, at the same time maintaining their adjacent surfaces parallel, that the
shafts can be set at any desired angle.
It will be readily understood with frictional gearing of the above description, that
the driven shaft may have forward advance motion, or may be reversed, as is desired,
by extending the driven shaft. see Fig. 2 and mounting thereon a second frictional
gear 10, as shown by the broken lines.
Thus if the shaft 2 has rotation, as indicated all portions of the gear 4 to the right
of the line x. x. have rotation towards the observer, while all parts to the left have
motion from the observer. If it is desired to actuate the shaft 3 towards the observer
the gear 5 is to be used, when reverse rotation is to be effected the gear 10 is
employed.
To simplify this mechanism and combine it in a more compact form, I have shown
in Figs. 3 and 4 a double cone gear 12, having its largest diameter midway of its
length and mounted upon the driving shaft 2. This gear it is evident, is a sub-
stantial equivalent of the two gears 5, 10 in Fig. 2. Co-operating with said gear
and secured upon the end of the driven shaft 3, is a recessed bevel gear 13; that
is, upon any diametrical vertical section, the opposite sides or active surfaces form a
re-entering angle, see Fig. 4. The bevel of the gear 13 is such that the opposite
sides are coincident with but do not touch the double cone gear 12. The latter has
endwise movement with the shaft 2 and by means of the belts 6, 6¹ the shaft 3 may
be rotated in either direction. With the shaft 2 rotating as indicated, and with the
belt 6 active, the shaft 3 is moving as indicated. The belts 6, 6' are supported upon
a rod 14 and adjustable lengthwise thereon by guide-eyes 15, 15, in order that the
points of contact of said belts with the frictional gears 12, 13 may be varied. The
speed of the driven shaft can thus be changed and altered, while its rotation can be
reversed, as circumstances may require.
In all instances where this frictional gearing is applied and when the main shaft is
kept continuously running the driven shaft is started and stopped by causing the gear
thereon to approach or retreat from the gear on the main line.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what I
claim is :
1st. The device for transmitting motion between two lines of shafting, not parallel,

page_text: substantially as described, composed of two shafts, two bevelled frictional gears
mounted on their adjacent ends, and a loose endless band encircling one of said
gears and adapted to pass between and be gripped by said gears as specified.
2nd. In frictional gearing by which motion is transmitted between two shafts not
in parallelism, the combination with two bevelled frictional gears and their supporting
shafts, of a loose endless band encircling one gear and adapted to be gripped by both,
and means for adjusting one of said gears to control the pressure upon the band,
substantially as and for the purposes herein set forth.
3rd. In frictional gearing of the class described, the combination with two bevelled
gears, one of which is flanged, and the shafts upon which they are mounted, of the
loose endless band encircling one of said gears and gripped by the adjacent
surfaces of the latter, and adjusting mechanism by which the gears are caused to
approach or separate, substantially as described.
4th. In a device for transmitting motion between shafts not in parallelism, the
shaft 2, its frictional bevelled gear 4, the shaft 3 having endwise motion, the frictional
gears 5, 10 oppositely disposed thereon and positioned diametrically of said gear 4,
combined with two endless bands, which loosely encircle said gears 5, 10 and
co-operate with gear 4, substantially as set forth and stated.
5th. In frictional gearing of the class described, the mechanism for transmitting
motion and for reversing the motion transmitted, as described, composed of a shaft
which carries a frictional gear provided with a re-entering active surface, a shaft
having end wise movement carrying a gear formed with two reversely conical surfaces,
and two adjustable endless bands, which operate independently upon said conical
surfaces and are gripped between the latter and the re-entering surface of the
co-operating gear, substantially as herein set forth.
6th. In mechanism for transmitting motion from one shaft to another, not parallel
with the first, a shaft provided with a bevelled frictional gear, a second shaft furnished
with conical gears oppositely disposed thereon, combined with two endless bands
loosely encircling said conical gears, and gripped between said gears and the bevelled
gear upon diametrically opposite portions of the latter, to render the driven shaft
revoluble in either direction as herein specified.
Dated Boston, Mass., February 7th 1889.