US1724067A

US1724067A - Electrical reproducer

Info

Publication number: US1724067A
Application number: US132096A
Authority: US
Inventors: Igor S Bobrovsky
Original assignee: Individual
Current assignee: Individual
Priority date: 1926-08-28
Filing date: 1926-08-28
Publication date: 1929-08-13
Anticipated expiration: 1946-08-13

Description

ELECTRI CAL REPRODUCER Filed Aug. 28, 1926 gum/whoa Patented Aug. 13, 1929..

UNITED STATES PATENT OFFICE.

ELECTRICAL REPRODUCER.

Application filed August as, 1926. Serial No. 132,096.

This invention relates to electrical reproducers for phonographs, and has for its object theproduction of'an efficient sound reproducing mechanism, wherein the magnetic flux in the pole pieces varies constantly with variations of the armature and follower or needle.

Another object of my invention includes the production of a construction which is simple in construction and reliable and effective in operation.

A Other objects will appear hereinafter, and I attain these objects by the construction illustrated in the accompanying drawings, in

which Fig. 1 is a plan view of a construction which embodies the principles of my inven- 'tion.

Fig. 2 is a plan view with the cover removed.

Fig. 3 is a sectional view taken on the line 33 of Fig. 1.

Fig. 4 is a view taken on the line 4- 1 of Fig. 2, and

Fig. 5 is a view of the armature and pole pieces.

The same numerals refer to like parts throughout the several views.

In a preferred form of construction, to which, however, I do not desire to be understood as limiting myself otherwise than as stated in the appended claims, I provide two permanent magnets 10 and 11. These magnets are preferably semi-circular in shape and are placed with their likepoles opposite pole pieces 12 and "13. These pole pieces are secured to the shell or casing 14, by any suitable means as

screws

15 and 16. For convenience, pole piece 12' may be re garded as the north pole and pole piece 13 as the south pole. The north pole is longer than the southpole, and it carries the magnetic coil 17 afiixed thereon at right angles to the axial line of the pole. The

respective ends

19 and 20 of the coil wire are secured to the lead wires 21 and 22 by binding pieces 23 and 24:. These pieces are carried on disk 25 of insulating material.

The south pole carries the armature 26, which is pivotally saddled on the pole by the pivot saddle 27, so as to swing back and forth in response to the motion of the record needle 28, as it follows the grooves in the record (not shown). The action of the armature causes the distance between the armature tail 2 9 and the north pole to vary, and consequently the magnetic flux therein and in coil 17 varies also. Any suitable means as spring 30, normally holds the tail 29 and the north pole spaced in proper relation. A 6 cap 31 protects the construction, and a thumb screw 82 holds the needle secure. The magnetic properties of the magnet pieces must be permanent, and I use for this purpose cobalt steel as best suited for my purose.

While I have shown and described a specific construction, Ido not thereby desire to be understood as having thus limited myself unnecessarily.

What I claim, therefore, as new and useful, and desire to secure by Letters Patent is:

1. An electric reproducer, comprising a pair of permanent magnets, pole pieces arranged between said magnets, a coil carried by one of said pole pieces, and a saddle piece pivotally mounted on the other of said pole pieces, said saddle piece carrying a needle and having a tail piece extending to the other of said pole pieces.

2. An electric reproducer comprising a pair of permanent magnets, pole pieces arranged between said magnets, a coil carried by one of said pole pieces, and a saddle piece pivotally mounted on the other of said pole pieces, said saddle pieces'carrying a needle and .having 'atail piece extending to the other of said pole pieces, and means for controlling the position of said saddle piece. I

-3. An electric reproducer comprising two permanent semi-circular magnets, a case for holding sald' magnets with their like poles opposite each ather, a pole piece between the north pole of the magnets and a pole piece between the south pole of said magnets, a coil carried bysaid north pole and a saddle piece carried by said south pole.

4. An electric reproducer comprising two permanent semi-circular magnets, a case for holding said magnets with their like poles opposite each other, a pole piece between the north pole of the magnets and a pole piece between the south pole of said magnets, a coil carried by said north pole and a'saddle piece carried by said south pole, said saddle piece having a needle for following the grooves in a phonograph record and a tail piece extending over a portion of the north 1O pole, and means for controlling the position of the saddle piece.

In testimony whereof I have hereunto set my hand on this 23rd day of August, A. 1).,

IGOR S. BOBROVSKY.