AN IMPROVED ELECTRO-MOTOR FOR SEWING MACHINES
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the
Office of the Commissioners of Patents, with his Petition, on the
22nd January 1870.-A communication from abroad by Gustave
Henry Dervieu, Merchant, of 13, Boulevart St. Martin, Paris.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County
of Middlesex, Patent Agent, do hereby declare the nature of the said
Invention for "AN IMPROVED ELECTRO-MOTOR FOR SEWING MACHINES," to be as
follows:-
In order that the improvements of this Invention may be the better
understood I will first describe an electro-motor which has been long in
use composed of two electro-magnets or pairs of coils disposed on each
side of a triangular frame, at the apex of which is mounted a shaft
carrying a wheel provided with a suitable number of armatures arranged
in a circle. At one end of the shaft above mentioned is keyed a small
toothed wheel, on which bear (one on either side) two insulated spring
blades, both being in communication with one pole of the battery by
means of the coils, the other part of the apparatus being in com-
munication with the opposite pole of the battery. The teeth of the
wheel form contact points with the spring blades, the intervening spaces
.

page_text: between the teeth producing the intermittent action. The wheel and
spring blades combined form what is termed a current distributor,,
serving to impart rotary motion to the large wheel by the alternate"
making and breaking of the circuit, which motion is utilized in any
suitable manner.
According to the present improvements in the above-described electro-
motor instead of a toothed distributing wheel I employ a wheel or roller
of wood or other non-conducting material, on the periphery of which are
inserted metal contact parts in communication with the large wheel.
I also employ rollers instead of the spring blades, the rollers being in
constant contact with the periphery of the wheel. In this manner a
rolling contact is substituted for the sliding contact before produced.
The electro-motor thus improved is rendered applicable for driving
sewing machines; and the Invention also consists in the application of
such improved motor to sewing machines generally. The electro-motor
is fixed at any suitable point on the framing of the machine, below the
work table for example, and transmits motion to the driving shaft by
the aid of band pulleys or other means.
Ta
The improvements also include the application of a commutator. to the
improved electro-motor, whereby the seamstress may employ four, six,
eight, or other number of elements of the battery, and thus augment or
diminish the speed of the machine as required.. Thc. commutator is
fixed on the work table within reach of the seamstress.
+
The improved electro-motor and commutator are illustrated in the
accompanying Drawing, Figure 1 of which shows an elevation of the
electro-motor on the side of the distributor, Figure 2 is an end view of
the apparatus, Figure 3 shows a separate plan of the distributor, while
Figure 4 shows the commutator as placed in communication with the
battery and apparatus. The reference letters apply to all the Figures.
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7.
a, metallic framing of the electro-motor b, b; b¹, b', electro-magnets or
coils fixed on each side of the frame, but insulated therefrom; c, large,
wheel of the motor, carrying armatures d in suitable number, and
mounted on a shaft e supported at the upper part of the framing a;
f, small wheel or roller (separately represented in Figure 3) made of
wood or other non-conducting material, and carried on one end of
shafte at back of frame a; g, metal contact parts disposed around
roller so as to be flush with its periphery; h, wood or other non-
conducting plate fixed on one side of the frame; i, a, friction rollers of

page_text: distributor in eonstant contact with the periphery of small wheelf, and
receiving rotary motion therefrom. The rotation of wheel brings the
friction rollers i, i, in alternate contact with the metal parts and the
wood or other non-conducting material of which the wheel is composed;
j,j, bearings of rollers i, i, fixed on plate ; k, binding studs, tho
one being in communication with the positive pole of the battery; and
the other with the negative pole; stud ¹ is also in communication
with the contact parts of small wheel f. The binding stud k is in
electrical communication with the coils b, b, which are in connection
with roller i, while roller communicates with coils ¹, b, the latter
being connected with stud . From the foregoing it will be understood;
that the wheel e will be rotated by the distributor, which alternately
opens and closes the circuit; t, pulley keyed on one end of shaft e and
transmitting motion to the sewing machine by the aid of band m.
The commutator represented in Figure 4 is composed of a small
tablet n, on which is pivoted a handlo a capable of being moved by hand
into contact with one or other of three copper plates fixed around its
centre of motion on the tablet n. By bringing handle o in contact with
the plates or s four or six elements of the battery may be employed for
driving the sewing machine at a greater or less speed as desired:
A represents the battery, and k, k', the two binding studs of the motor;
the positive pole is directly attached to the motor, and the negative pole
of the sixth clement to the small stud 7 of the commutator com-
municating with the plates marked "fast." Another conducting wire
transmits the current from the fourth element to the study connected
with the plate s¹ marked "slow." From, the foregoing it will be under-
stood that by moving lever o so that its spring may effect contact with
the "slow" plate s¹ the motor will be operated by four elements only,
said plate s being connected with the fourth clement of the battery A.
If on the contrary the lever o be brought in contact with the opposite
plate s marked "fast," the motor with then work with six elements, said
plate's being in communication with the sixth element of the battery.
Lastly, if lever o be brought in contact with plate t the current will be
interrupted, and the motor will cease to act.
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