Improvements in Differential Apparatus for Transmitting, Regulating, and Controlling Rotary Motion.
Year: 1897

page_text: Date of Application, 15th Jan., 1897
Complete Specification Left, 15th Oct., 1897-Accepted, 20th Nov., 1897
PROVISIONAL SPECIFICATION.
Improvements in Differential Apparatus for Transmitting,
Regulating, and Controlling Rotary Motion.
We HENRY BARMBY of 32 Church Street, Preston, in the County of Lancaster
Engineer, and JOHN HENRY TOULMIN of 81 Fishergate, Preston, aforesaid, Engineer,
do hereby declare the nature of this invention to be as follows:-
Our said invention relates to improvements in differential gear apparatus for
transmitting, regulating and controlling rotary motion and applicable to various
purposes such for instance as the propulsion, steering and braking of road vehicles,
the elevating of goods, the stamping drawing and pressing of metals and materials
the obtaining of slow motions in machinery and for other purposes. The construction
and arrangement of our improved apparatus would vary according to the object or
mode of application, but under a suitable arrangement the parts might be mounted
between two frames or cheeks connected by suitable stays or bolts. A stud secured
to one of the frames would project through the other and upon this stud we mount
a boss occupying a bearing in the cheek which the stud passes through, the said
boss having formed on or attached to it a cylindrical extension which is excentric to
the boss. Upon the excentric we mount loosely a toothed pinion which gears with an
internally toothed spur wheel which is carried on the stud, the pinion being less in
diameter than the spur. The internally toothed spur wheel is the wheel which
transmits the required ultimate motion. Besides gearing with the said internally
toothed spur wheel, the pinion also gears with an internally toothed annular wheel of
about equal diameter with the internal spur and which is carried in an annular race
secured to the cheeks or frame of the apparatus, the back of the said annular wheel
being turned so as to run smoothly in the race. Through the thickness of the race
we insert a number of loose blocks the inner ends bearing upon the back of the
annular wheel while the outer ends are embraced by a brake strap operated
by a lever and excentric. If the brake strap is tightened by the lever
and excentric so as to force the blocks against the annular wheel, the latter is
held stationary and the differential motion corresponding to the difference between
the number of teeth in the excentrically revolving pinion and the internally toothed
spur and annular wheel is imparted to the said spur wheel. The said spur wheel
transmits the motion by gear wheels, chains or other media, suitable to the purpose
for which the apparatus is designed. The primary driving motion may be imparted
to the boss and excentric by a handle, crank, toothed wheel, band or the like. For
instance in a motor-car we might couple the motor direct to the crank on the said
boss and so drive direct. When a constantly working motor is used, by manipulating
the brake strap lever, the differential transmitting mechanism can be independently
started and stopped or re-started at will. We might introduce reversing means by
carrying a pair of intermediate transmitting wheels upon a swing bracket or quadrant
pivotted upon the axis of the intern il spur wheel or on the aforesaid stud, or in any
other suitable position. By setting one or other of the transmitting wheels into
gear with the wheel to be driven, reversal of the motion is obtained. When stopped
the apparatus is practically locked in position, if the annular wheel is braked.
We

page_text: might also provide for the obtaining of different speeds from a constant motor speed
by providing several excentrically revolving wheels of different diameters or pitches
Each
and a corresponding number of annular wheels engaging with the same.
annular wheel is provided with a separate braking strap, so that when a certain speed
is required it is only necessary to operate the brake strap of the ring which gives the
required speed. The annular wheels might be furnished with ball or roller bearings
in the races so as to reduce friction. Instead of an arrestable annular wheel as
described, to bring about the differential motion we might form the excentrically
revolving pinion with a square or other suitably shaped boss to play in a corresponding
recess or recesses in the cheek or frame. By this means the required transmission of
The latter construction is
differential motion to the internal spur is obtained.
suitable for snatch blocks, and pullies for hoisting purposes, and is also convenient in
a modified form for steering purposes for motor-cars and the like, the boss and
excentric being worked by a box key or other means from the driver's or conductor's
platform.
Dated the 14th day of January 1897.
Improvements in Differential Apparatus for Transmitting,
Regulating, and Controlling Rotary Motion.
We HENRY BARMBY of 32 Church Street, Preston, in the County of Lancaster,
Engineer, and JOHN HENRY TOULMIN of 81 Fishergate, Preston, Aforesaid, 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 and accompanying drawings:-
:―
Our said Invention relates to improvements in differential gear apparatus for
transmitting, regulating and controlling rotary motion, and applicable to various
purposes such for instance as the propulsion, steering and braking of road vehicles,
the elevating of goods, the stamping, drawing and pressing of metals and materials,
the obtaining of slow motions in machinery and for other purposes.
And in order that our invention may be fully understood we have annexed hereto
two sheets of explanatory drawings to which we will now refer.
Loid drawinga

page_text: to the object or mode of application.
Under a suitable arrangement as shown
in Figs. 1 and 2 the parts are mounted between two frames or cheeks A B connected
together by stays or bolts a. A stud b formed with a collar b¹ is secured to the
cheek A by a nut 62. This stud b projects through the frame or check B. Upon the
stud b we mount loosely a boss c occupying a bearing in the cheek B, the said boss c
having formed on or attached to it cylindrical extensions c¹ c² which are excentric to
the boss and are of varying throw as clearly indicated in the drawings.
Upon the excentrics c¹ c² we mount loosely toothed pinions d d' and d².
The pinions d, d¹ are loosely mounted upon the excentric c¹ and the pinion d² is
loosely mounted on the excentric c². The pinions d d¹ d² are secured together by a
pin d³.
d
The pinion & gears with an internally toothed spur wheel e loosely mounted on the
stud b. The internally toothed spur wheel e is also formed with teeth on its external
periphery and this spur wheel e is the wheel which transmits the required ultimate
motion. Instead of external spur teeth the spur wheel e may be formed as a pulley
to transmit the motion by a belt.
The pinions d¹ d² gear with internally toothed annular wheels fg which are carried
in an annular race g₁ secured to the cheeks A B by bolts or other suitable means as
shown in Fig. 1 of the drawings. Through the thickness of the race we insert a
number of loose blocks h the inner ends bearing upon the peripheries of the annular
wheels fg whilst the outer ends are embraced by and secured to a brake strap i
operated by levers i¹, one of such levers being clearly shown in Fig. 2. Suppose the
brake strap be tightened by the lever so as to force the blocks h against the annular
wheel the annular wheel g running idle, the wheel f is held stationary and the
differential motion corresponding to the difference between the number of teeth in
the excentrically revolving pinion d' and the internally toothed spur wheel e and
annular wheel fis imparted to the said spur wheel e. The spur wheel e transmits
the motion by gear wheels, chain or other media suitable to the purpose for which
the apparatus is designed. A lower speed may be obtained by allowing the annular
wheel to run idle and braking the annular wheel with which gears the pinion d²,
which it will be noted, is of larger diameter than the pinion d', and would therefore
drive the spur wheel e at a correspondingly lower speed.
We do not confine ourselves to the number of excentrically revolving driving
pinions shown, as any convenient number, of different diameters or pitches, and a
corresponding number of annular wheels engaging with the same might be used.
Also if desired one excentrically revolving driving pinion only may be employed.
It is obvious that the speed imparted to the spur wheel e may be reduced to any
required degree by slackening the brake band on the annular wheel for g and so
allowing the annular wheel to slip to some extent.
The primary driving motion may be imparted to the boss c and excentrics c¹ c² by
a handle, crank, toothed wheel, band or the like. For instance in a motor car we
night couple the motor direct to the crank on the boss c and so drive direct.
When a constantly working motoris is used, by manipulating the brake strap lever,
the differential transmitting mechanism can be independently started or stopped, or
restarted at will. The annular wheels f and g may be furnished with ball or roller
bearings in the race so as to reduce friction. When stopped the apparatus is
practically locked in position if the annular wheel for g is braked.
Instead of an arrestable annular wheel as described to bring about the differential
motion, we might form the excentrically revolving pinion with a square hexagonal or
any other suitable shaped boss to play in a corresponding recess or recesses in the
cheek or frame.
This is more particularly shown in Sheet 2 of the drawings to which we will now
refer.
The cheek A of the apparatus is formel or provided with a stud j upon which is
5 loosely mounted a flanged pulley & formed with internal spur teeth as shown. The
flanged pulley le is provided with a hole to secure the end of a winding cord. Upon
a prolongation of the stud j we loosely mount an excentric boss carried by a

page_text: handle or crank . This excentric boss and handle is separately shown in Fig. 6.
The excentric boss carries a pinion m which is formed with projections m¹.
The cover B of the apparatus which is secured to the cheek A is formed with
corresponding recesses as will be clearly seen from an inspection of Fig. 5. A cap n
secured to the handle shrouds the stud j¹ and serves to prevent tampering with the
pin o which secures the handle and boss upon the stud j¹.
On revolving the handle the projections m¹ engage with the recesses in the
fixed cover B as the pinion m is revolved and lock the pinion m on the excentric 1,
and thus the required transmission of the differential motion to the internally
toothed pulley k is obtained.
On releasing the handle one or more of the projections m' engaging with the
recesses in the cover B locks the apparatus.
To unwind the cord from the pulley & the revolution of the handle is reversed.
This construction is suitable for snatch blocks, pullies for hoisting purposes and
the like.
Having now particularly described and ascertained. the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is.
(1) The improved differential speed gear of the indicated' nature consisting of the
revolving excentric or excentrics with pinions loosely mounted thereon, gearing with
internally toothed annular wheels which are capable of being braked so as to transmit
motion through the pinions to an internally toothed spur wheel from which the
required ultimate motion is obtained, in the manner by the means and substantially
as described and shown.
(2) The general arrangement construction and combination of parts comprising the
improved differential speed gear substantially as described and illustrated in Sheet. 1
of the drawings.
(3) The modified construction of differential gear consisting of the revolving
excentric, having a pinion loosely mounted thereon formed with projections engaging
with correspondingly formed recesses in the frame of the apparatus so as to transmit
motion to a pulley or its equivalent formed with internal spur teeth gearing with
the pinion substantially as described and shown.
(4) The general arrangement construction and combination of parts comprising
the differential speed gear substantially as described and illustrated in Sheet 2 of the
drawings.