Improvements in Friction Driving Gear for Dynamo Electric and other like Machinery.
Year: 1892

page_text: Date of Application, 25th Jan., 1892
Complete Specification Left, 4th Aug., 1892-Accepted, 10th Sept., 1892
PROVISIONAL SPECIFICATION.
Improvements in Friction Driving Gear for Dynamo Electric and
other like Machinery.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of
Middlesex Gentleman do hereby declare the nature of this invention which has
been communicated to me from abroad by Armand de Bovet of 47 Rue Taitbout
Paris in the Republic of France Engineer to be as follows:-
This invention is designed to provide means for driving dynamo electric
machines by friction and is applicable in all cases where motion is transmitted by
friction and an electric current is available.
Take for instance the case of a dynamo arranged upon its supports in such a
manner as to be capable of a very slight displacement in such a manner as to give
it a tendency under the influence of a spring or of its own weight to cause its
pulley or drum to press against the fly or motor wheel from which it receives
motion or by which it is driven and admitting on the other hand of being fixed
when not required to work, in a position in which the pulley or drum is out of
contact with the fly or driving wheel.
When under these conditions the pulley is applied against or brought in contact
with the motor wheel there being at this moment no current generated by the
machine the slight pressure resulting from the action of the spring or weight is
sufficient to start the machine and commence driving it by friction but directly a
current begins to be generated in the dynamo the resistance increases and the
friction ceasing to be sufficient to transmit the motion the machine comes to a
standstill.
Now according to the present invention this stoppage is obviated by providing
the pulley of the dynamo with a coil of wire which by means of a suitable device
such as two rings placed on but insulated from the shaft and two brushes is caused
to form part of the circuit of the dynamo.
This wire is wound or coiled in the pulley which may be enlarged or widened
in order to provide sufficient space to accommodate the amount of wire required.
Under these conditions when the dynamo commences to generate or supply a
current the adhesion of the magnetised pulley to the motor wheel increases in the
same proportion as the resistance of the machine increases and thus ensures the
continuous propulsion of the said pulley.
In fact the effect of attraction varies at the same time and in the same direction
as the work required of the dynamo the adhesive power of the pulley augmenting
in a somewhat analogous manner to the augmentation of the magnetic field of the
inducing magnets.
According to the nature of the dynamo the pulley may be arranged to receive
either the whole of the current of the machine or a derived current or simply the
exciting current but it is evident that a current dependent on the working of the
dynamo is preferable to a constant current.
The same mode of driving may be employed for receiving dynamos or electric
motors as for generators.
The rim of the pulley may be of conical or bevelled form in section the fly or
motor wheel being of corresponding shape.
In this case the straight section of the fly or motor wheel should be of such a
form as to enable it at the time of making contact to enter entirely within the
groove in order to obviate the direct waste of action caused by the presence of air
between the nearest or adjacent parts of the groove in the pulley.
Moreover when the acting surface of the driving or motor wheel forms a straight

page_text: line in section the corresponding surface of the driven wheel or pulley should form
a flat curve having the convex side towards the driving wheel.
By these means unnecessary friction and wear of the parts in contact owing to
the different speeds are obviated and provided that the radius of the curve is of
sufficient length the distance between parts of the surfaces of the wheels is so small
as to have no prejudicial effect upon the action.
The pulley or driven wheel may be arranged tangentially, laterally, internally or
in any other convenient position relatively to the driving wheel.
Dated this 25th day of January 1892.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Friction Driving Gear for Dynamo Electric and
other like Machinery.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this invention (which has been com
municated to me from abroad by Armand de Bovet of 47 Rue Taitbout Paris in
the Republic of France Engineer) and in what manner the same is to be performed
to be particularly described and ascertained in aud by the following statement:-
The object of this invention is more especially to provide means as hereinafter
described for driving dynamo electric machines by friction but it is applicable in all
cases where motion is to be transmitted by friction and an electric current is
available.
Take for instance the case of a dynamo with its revolving parts arranged upon
the support in such a manner as to be capable of a slight displacement and that
under the influence of a spring or by reason of its own weight its pulley or
drum will press against the fly wheel or motor wheel from which it receives
motion or by which it is driven but capable when the machine is not required
to work of being fixed in a position in which the pulley or drum is out of contact
with the fly wheel or driving wheel.
In such an arrangement when the pulley or drum is applied against or brought
into contact with the fly wheel or motor wheel the slight pressure due to the action
of the spring or weight is sufficient to start the machine and commence driving it
by friction but directly a current begins to be generated in the dynamo the
resistance to the driver increases and the friction ceases to be sufficient to transmit
the motion. According to this invention means are provided whereby this objection
is overcome.
I will describe the invention with reference to the annexed drawing.
Figures 1. 2 and 3 shew in section dynamo pulleys in frictional contact with fly
wheels illustrating the application of this invention thereto. In Figure 1 the
pulley X of the dynamo is provided with a coil of wire a which (by means of two
rings placed on but insulated from the shaft Y and two brushes or otherwise) is
caused to form part of the circuit of the armature of the dynamo.
The wire is wound or coiled in the pulley whose inner sides may be recessed or
widened parallel with the line A. B. in order to provide sufficient space to accom-
modate the amount of wire required. When the dynamo commences to supply or
generate a current the pulley X becomes magnetised and the adhesion of the said
pulley to the fly wheel Z increases as the resistance of the machine increases and
thus ensures the continuous propulsion of the said pulley.
In fact the effect of attraction varies at the same time and in the same direction
as the work required of the dynamo the adhesive power of the pulley augmenting
in a somewhat analogous manner to the augmentation of the magnetic field of the
inducing magnets.

page_text: According to the nature of the dynamo the pulley may be arranged to receive
either the whole of the current of the machine or a derived current or an inde-
pendent exciting current but it is evident that a current dependent on the working
of the dynamo is preferable to a constant current.
The invention may be applied to either electric motors or to electric generators
and when applied to motors the dynamo pulley will become the driver and the
wheel Z will be the driven wheel.
The rim of the pulley may be of conical or bevel form in section the fly or
motor wheel being of corresponding shape. Figure 2 shews an example of this
in which the rim of the pulley X is shewn with a conical recess around its
periphery the periphery of the motor wheel having a corresponding shape. In
this case the section of the motor wheel should be of such a form as to enable it
at the time of making contact to enter entirely within the groove in order to obviate
the direct waste of action caused by the presence of confined air in the recess in
the pulley. When the acting surface of the motor wheel Z forms a straight line
in section as at m. n (see Figure 3) the corresponding surface
PI of the driven
wheel or pulley X should form a flat curve having the convex side towards the
driving wheel. By these means unnecessary friction and wear of the parts in
contact owing to the different speeds are obviated and provided that the radius of
the curve be of sufficient length the distance between parts of the surfaces of the
wheels is so small as to have no prejudicial effect upon the action.
The pulley or driven wheel may be arranged tangentially internally or in any
other convenient position relatively to the driving wheel.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is;
1. In frictional driving gear for dynamo electric machines (generators or motors)
or other like machines the combination of an electric circuit for increasing the
adhesion or frictional driving contact substantially as hereinbefore described.
2. In frictional driving gear for dynamo electric machines a magnetic pulley on
the axis of the dynamo the said pulley being magnetised by a current dependent
on the current of the dynamo substantially as hereinbefore described.
3. In frictional driving gear for dynamo electric machines the combination with
the driving wheel of a magnetic pulley in frictional contact therewith and wires
in connection with the wires in which the current of the machine passes so that
during the working of the machine the magnetism (and consequently the adhesion
or frictional contact) varies in proportion to the production of the current in or by
the machine substantially as herein before described.
4. The constructions or arrangements of electrically controlled friction gear
substantially as herein before described and shewn in the several figures of the
accompanying drawing.