An Arrangement for Working an Electrical Rock Drill or similar Apparatus.
Year: 1892

page_text: Date of Application, 15th Sept., 1892
Complete Specification Left, 14th June, 1893-Accepted, 15th July, 1893
PROVISIONAL SPECIFICATION.
An Arrangement for Working an Electrical Rock Drill or similar
Apparatus.
ALBERT LESTER TAYLOR Electrical Engineer Prudential Buildings 36 Dale
Street Liverpool, do hereby declare the nature of this invention to be as
follows:-
As in the case of a steam engine, which, having been started, automatically opens
or shuts a valve which admits or cuts off a supply of steam, so I propose in the
case of an electrical rock drill or similar apparatus to automatically commutate, or
to entirely or partially cut off or admit a supply of electricity to a solenoid or
solenoids or similar apparatus by causing the motion of the spindle or otherwise to
impart pressure to a substance whose resistance is varied by pressure (such as a
number of carbon discs or of pieces of carbon cloth) and by this means to commutate
or vary the flow of current in one or more solenoids or in similar apparatus which
variation shall act by lessening or increasing the force exerted or shall change the
direction in which the force shall act, thus the current might be commutated
entirely or partially from a solenoid in front to a solenoid at the back by means of
the simultaneous compression of a number of carbon discs inserted in series
with the solenoid at the back and a relaxation of the pressure on a number of
carbon discs inserted in series with the front solenoid and vice versa, metallic or
rubber or other springs being used to prevent destructive percussion or pressure on
such resistances and to assist rapid relaxation of the electrical contact in the mass
of the resistance, when the pressure is removed.
Dated this Fourteenth day of September 1892.
ALBERT LESTER TAYLOR.
COMPLETE SPECIFICATION.
An Arrangement for Working an Electrical Rock Drill or similar
Apparatus.
I, ALBERT LESTER TAYLOR, of Prudential Buildings, 36, Dale Street,
Liverpool, Electrical 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 :-
This invention relates to that class of apparatus in which a reciprocating move-
ment is obtained by the alternate action of fixed solenoids or coils on moveable
cores, or moveable solenoids on fixed cores, or of other similar contrivances, and
consists of a special means for commutating or directing the energising electric
current into the respective solenoids or other coils.
Coupled in series with each coil is a variable resistance consisting of carbon
plates, sheets of carbon cloth, granulated carbon or metal, or of any other material
or construction such that its resistance to the passage of an electric current can be
materially lessened (or increased) by the application of mechanical pressure.
The two variable resistances and their respective coils are connected in parallel
in the electric circuit and are alternately compressed by an arm carried by the
drill spindle or other reciprocating part, or through other convenient mechanism
hereinafter referred to as the compressor, as, for instance, by a local electric circuit
and an electro magnet, or by compressed air discharged from a reservoir or specially
compressed at each stroke, &c.
The electrical connections are so made that the compressor, travelling to the end

page_text: of its stroke and compressing one resistance while removing pressure from the
other, thereby turns the current, or the greater part, into the solenoid which now
withdraws it to the other end of its stroke.
This invention is clearly shewn in the accompanying drawing, in which (a.) is a
conductor conveying current to a middle point of a solenoid (e.), which current will
flow through the two halves of the solenoid in inverse proportion to the respective
resistances of the two halves of the variable resistance (b).
The amount of the resistance in each half of (b) being variable by pressure will
be determined by the position of the compressor (f).
If the drill (d.) be pushed towards the solenoid (e.) so that the core (c.) is pushed
further into the back half of the solenoid the compressor (f.) will also have then
compressed the back resistance and released the front resistance (b.).
This will result in the greater part, if not the whole, of the current, entering
through (a.), taking the path (of least resistance) through the front half of the
solenoid (e.) and the back half of the resistance (b.).
Following this, the core (c.) will now be drawn into the front half of th solenoid (e.),
the compressor (f.) will release the back resistance and compress the front
resistance (.) which action will cause the flow of current to be changed from the
front to the back half of the solenoid (e.) and will now so cause the core (c.) to be
drawn again into the back half of the solenoid (e.) and so on.
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 percussive rock drill or other apparatus depending for its action upon the
alternate energising of electromagnets or equivalent, commutating or switching
the electric current by varying the relative resistances of two parallel paths,
substantially as described, and as illustrated in the accompanying drawing.
2. The use of a series of sheets (or other arrangement) of carbonized cloth (or
other substances whose resistance is varied by pressure) for the purpose of com-
mutating or switching the electric current, substantially as described.
3. In connection with the variable resistance above described, the use of metallic
or other springs or of compressed air or other similar artificial aid to better
separate the component parts of the variable resistance after pressure has been
applied and then released.
Dated this 13th day of June 1893.
A. LESTER TAYLOR,
Applicant.