Improved Electromagnetic Tooth Stopping Hammer.
Year: 1899

page_text: Date of Application, 3rd May, 1899-Accepted, 23rd Sept., 1899
COMPLETE SPECIFICATION.
Improved Electromagnetic Tooth Stopping Hammer.
I, CURT OSTMANN, of 81, Ohlauerstrasse, Breslau, Germany, Dentist, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement:-
This invention relates to an electro-magnetic hammer for use in stopping the
teeth, all the working parts of which are concealed in a single tube which serves
as handle.
In the accompanying drawing the subject-matter of the invention is repre-
sented in section.
Two soft iron cylinders and z are circumscribed by an electric current which
flows through a coil d of insulated copper wire, as soon as the instrument is
connected to a suitable source of electricity. By this means both cylinders
and are converted into electro-magnets. The iron cylinder x is situated about O,
4mm from the second cylinder and can only be moved forwards against the
weak spring f. The second iron cylinder serves as hammer and strikes on e at
the moment the circuit is closed, thus driving the iron cylinder forwards and
somewhat compressing the weak spring f. As soon as the circuit is interrupted
the spring moves the iron cylinder back into its original position. The iron
cylinder z is suspended from a springs and carries a platinum pin p which bears
against a piece of platinum foil o soldered to the spiral spring n. This point of
contact of the pin o and foil is the point at which the current is automatically
interrupted.
The passage of the current is as follows:-
An electric current of 6 volts electromotive force and 3 ampères strength enters
at a, passes through the spiral spring n, the piece of platinum foil o, platinum
pin p, spiral s, which is connected with the metal tube, to w, where the one end
of the wire coil d is soldered. From thence the electric current passes through.
the coil of insulated copper wire and out at k, after being led through the caout-
chouc b, back to the source. In consequence of the cylinder z being strongly
attracted towards a, the current is interrupted at o. The circuit closes again by
the action of the spring s. In this manner the iron cylinder = strikes repeatedly
and rapidly upon the part e of the cylinder a.
In the drawing the sliding switch for starting the instrument is not shown.
It is arranged at the front, being opened and closed by sliding a metal plate.
The sliding contact is analogous to that used in the known Bonwill electro-
magnetic hammer. The force of the blows can be regulated by means of a
rheostat or by advancing the cylinder, whereby the distance between x and z is
increased and the magnetic action and, consequently, the force of the blows
weakened

page_text: Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
1. Electromagnetic hammer for use in stopping teeth, characterized by two
soft iron cylinders arranged behind each other within a casing or the like which
attract and repel each other under the action of an electric current and spring (f),
whereby the continuance of the hammering can be regulated according to desire
'during the operation of stopping.
2/. A modification of the hammer for use in stopping teeth set forth in
Claim 1, characterized by a metal tube within which two soft iron cylinders are
arranged behind each other at a slight distance apart which cylinders are con-
verted into electromagnets by the electric current circulating around the metal
tube and attract and repel each other by means of an interrupter thus exercising
the hammering action.
3/. A modification of the hammer for use in stopping teeth set forth in Claim 1,
characterized by the fact that all the parts of the electro-magnet are arranged
in a common cylindrical casing with conical end, in order to give a smooth
form and facilitate the handling of the instrument.
Dated this 3rd day of May 1899.
ROBERT E. PHILLIPS,
Chartered Patent Agent,
70, Chancery Lane, W.C., Associate Agent.