Improvements in and relating to Electro-magnetic Tools.
Year: 1894

page_text: Date of Application, 8th May, 1894-Accepted, 28th July, 1894
COMPLETE SPECIFICATION.
Improvements in and relating to Electro-magnetic Tools.
A communication from abroad by ABRAHAM GEORGE FONDA, of No. 628,
Fourth Street, Louisville, in the County of Jefferson and State of Kentucky,
one of the United States of America, Manufacturer of Electro-magnetic
Tools.
I, PETER JENSEN, of No. 77 Chancery Lane, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
This invention has relation to certain new and useful improvements in electro-
magnetic tools wherein a hammer rod or plunger is actuated to a rapid reciprocating
movement under the influence of a pair of electro-magnets upon an armature which
carries said rod or plunger, said armature being situated between the like poles of
said magnets and itself carrying a coil energized by an alternating current.
In the accompanying drawings representing the invention, Figure 1 is a longi-
tudinal section of the invention as usually constructed, and embodied in a tool
especially designed for cutting stone and other hard substances.
Figure 2 is a detail view of one of the magnet cores as preferably constructed.
In these drawings the letter A designates a hollow cylinder, case or shell in
which the working parts are for the most part inclosed.
Supported centrally in said cylinder is a hollow spool B, of considerably less
diameter than the cylinder and divided into three sections, b, b', b². Said cylinder
is split longitudinally, and is preferably made of aluminum bronze although other
material may be employed.
Around each of said sections or portions b, b', 62 is wound a coil or helix, said
coils or helices being designated respectively by the letters C, C1, C2, the end
coils C, C² being wound in such a manner that their inside ends will have the same
polarity, when the current wires c, c' are properly connected in an electric circuit.
The middle coil or helix is energized by means of wires d, d¹ which are supplied
with a rapidly alternating electric current.
Placed inside the portion of the spool B, and rigidly secured to the end plate e
of the cylinder A, is a core cylinder D, formed with a longitudinal bore e', said
core forming with the coil C, an electro-magnet. Secured to the opposite end
plate of the cylinder is a similar core D' with the exception that its bore e³ does
not usually extend entirely through it.
This core with the coil C³ forms a second electro-magnet, the inner ends of these
magnets C, C2 having the same polarity, as above stated.
D' designates a third core between the two cores D, D2, and shorter than the
distance between said cores, this core D' being capable of a free end wise movement,
forming, under the influence of the alternating current coil C¹ an electro-magnetic
armature of rapidly changing polarity.
F is an axial, or central hammer rod or plunger, which is formed of bronze or
some other material having no magnetic power. This central rod hammer or
plunger passes through the core D' which rigidly attached thereto, its upper end
portion working loosely in the slot or bore e³ of the core D, and against a spring G
seated therein, its opposite portion passing loosely through the bore of the core D,
beyond which it projects.
Threaded to an axial extension G of the said core D, is a tubular portion H
which forms a seat and guide for an anvil piece or bit carrier J upon which the

page_text: hammer rod or plunger operates. H¹ is a spring or hopper seated in said tubular
portion H, and engaged by a guide flange or collar hon said anvil piece or bit
carrier, its purpose being to retract the anvil piece or carrier. J' is a pin passing
through the lower portion of the tube H, and loosely engaging a guide slot in
the anvil piece or carrier, said pin preventing said carrier from rotating, and also
limiting its vertical movement. K is a bit or cutter.
Qis a cap which closes the opposite end of the cylinder H, A, said cap being
removable for the purpose of access to the electro-magnets, which may be readily
renewed or replaced.
R is a tubular extension of the said cap through which the current wires are led.
The cores D, D² may consist of a plain cylinder, but are preferably slotted
lengthwise and radially as seen in Fig. 2, this construction reducing their tendency
to become heated under the currents.
The core D¹ is preferably made up of a ribbon of soft iron tightly coiled,
varnished, and supported by a soft iron disk S.
The tool being properly connected up in electric circuits of the requisite character,
the armature magnet is situated in an intense magnetic field, and its own polarity
being rapidly reversing, it is successively attracted and repelled by the two end
magnets producing a rapid reciprocation of the rod or plunger with telling effect
upon the bit or other implement to which its blows are transmitted.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that
what I claim is-
"An electro-magnetic implement having a pair of end cores, energizing coils
surrounding said cores, a movable core between said end cores, and capable of a
reciprocating movement, an energizing coil surrounding said movable core, a hammer
rod or plunger attached to said central core, current wires for supplying the proper
currents to said cores, and a tool arranged to be acted upon by said plunger or
hammer rod, substantially as specified.'
Dated this 8th day of May 1894.
JENSEN & SON,
77, Chaucery Lane, London, W.C., Patent Agents.