US3236526A

US3236526A - Folding tone arm for a phonograph

Info

Publication number: US3236526A
Application number: US320207A
Authority: US
Inventors: Jr Michael J Capparelli
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1963-10-30
Filing date: 1963-10-30
Publication date: 1966-02-22
Anticipated expiration: 1983-02-22

Description

Feb. 22, 1966 M. J. CAPPARELLI, JR 3,235,525

FOLDING TUNE ARM FOR A PHONOGHAPH Filed Oct. 50, 1963 FIG.I.

INVENTOR:

WQM HIS ATTORNEY.

MICHAEL J. CAPPARELLLJR.

United States Patent 3,236,526 FOLDING TONE ARM FOR A PHONOGRAPH Michael J. Capparelli, Jr., Rome, N.Y., assignor to General Electric Company, a corporation of New York Filed Oct. 30, 1963, Ser. No. 320,207 6 Claims. (Cl. 27423) This invention relates to an improved tone arm construction, and in particular to a foldable tone arm mechanism for use with phonograph records of the disc type.

In many phonograph applications it is important that the phonograph unit be of very compact structure. To help achieve such a goal, it has been found desirable to provide a new and improved tone arm arrangement which readily lends itself to use in such a structure. Accordingly, an important object of my invention is to provide an improved phonograph tone arm mechanism which is readily foldable into a compact configuration when not in use.

Another object of my invention is to provide an improved folding tone arm construction wherein wiping contact engagement is utilized to achieve a foldable connection to a pickup cartridge.

An additional object of my invention is to provide an improved tone arm construction which includes a pair of pivotally linked arms and one or more pairs of wiping contacts carried by the arms to provide an uninterruped connection to a pickup cartridge during a predetermined anlgular movement of one of said arms relative to the ot er.

In carrying out my invention, in one form thereof, I apply it to a folding tone arm mechanism which includes two pivotally associated arms and a pickup cartridge. A first one of the arms is supported at one of its ends for pivotal movement in both vertical and horizontal directions relative to a turntable. The second arm is pivotally supported on the free end of the first arm so that it may serve as an extension of the first arm for operation of the phonograph, or alternatively, it may fold back upon the first arm to provide a compact tone arm mechanism. The pickup cartridge is secured to and supported by the free end of the second arm. To provide an effective electrical connection to the pickup cartridge, one or more wiping contacts is carried on one of the folding arms and arranged to cooperatively engage an associated contact carried by the other arm. Such a tone arm arrangement has been found to achieve a very compact and efficient structure.

Further aspects of my invention will become apparent hereinafter, and the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which I regard as my invention. The invention, as to organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description when taken in conjunction with the accompanying drawing, in which:

FIG. 1 is a perspective view of a tone arm mechanism embodying one form of my invention;

FIG. 2 is an elevation view of the tone arm mechanism of FIG. 1 in operation, with part of the supported end thereof not shown, for purposes of simplicity;

FIG. 3 is a bottom view of the arm mechanism of FIG. 2;

FIG. 4 is an elevation view of a tone arm mechanism embodying my invention in alternate form thereof;

FIG. 5 is a bottom view of the tone arm mechanism of FIG. 4; and

FIG. 6 is an elevation view of the tone arm shown in FIG. 1, with the outermost arm folded into retracted position.

Referring now to the drawing, and at first to FIGS. 1 and 2 thereof, there is illustrated a foldable tone arm mechanism 1 embodying one form of my invention. The tone arm mechanism 1 includes a first elongated arm 3 pivotally supported upon a bearing assembly 5, a second arm 7 pivotally supported on the free end 9 of the first arm 3, and a pickup cartridge 11 secured to free end 13 of the second arm 7.

The bearing assembly 5 is mounted upon an L-shaped supporting tube 15, and it includes a tone arm support 17 which swivels about a sleeve 19. The sleeve 19 cooperates with a reduced upper end 21 of tube 15. The tone arm support 17 is thus arranged to rotate about an axis perpendicular to the turntable (FIG. 2). Support 17 also includes a pair of apertured uprights 23 which rotatably receive and support a bearing pin 25 secured to the supported end of arm 3. The pin 25 is arranged in the uprights 23 of tone arm support 17 so that the arm 3 is permitted to rotate vertically in conventional fashion, about an axis parallel to the surface of the turntable.

For the tone arm mechanism 1, the

arms

3 and 7 are each constructed from a rigid and sturdy acetal resin insulative material, as for example, one of the superpolyoxymethylenes.

Turning now to an important aspect of the present invention, which concerns itself with an improved means for enabling the tone arm mechanism 1 to be compactly folded when not in use, attention is directed to the left side or free end 9 of the elongated arm 3, as shown in FIGS. 1-3. At free end 9 of the arm 3 there is formed a hub 29. Hub 29 has a downwardly facing bearing contact with a contiguous upwardly facing surface of the pivotally supported end 31 of arm 7. More particularly, the hub 29 may include housed therein a plurality of ball bearings (not shown) for bearing engagement with the upwardly facing surface on end 31 of arm 7 (viewing FIG. 2). The arm 7 is held in rotatably supported engagement with arm 3, by means of screw 33 which is extended through aligned apertures of hub 29 and arm end 31, and threaded into engagement with hexagonal nut 35 (FIG. 3). The screw 33 may be readily adjusted into engagement with its associated nut 35 to obtain the desired amount of frictional engagement between the

arms

3 and 7. For normal operation of tone arm mechanism 1, arm 3 is in frictional engagement with arm 7, and arm 7 does not pivot with respect thereto.

To eliminate any need for bending wires connected to the pickup cartridge 11 carried by pivotally supported arm 7, in accordance with my invention there is provided a foldable electrical connection afforded by two pairs of wiping contacts 37 and 39 (FIG. 3). More particularly, as best shown in FIG. 2, on the bottom surface 41 of the insulative arm 3, near the free end 9 thereof, there is secured a pair of spaced apart conductive shoes 43 and 45.

The shoes 43 and 45 are spaced apart laterally on the tone arm 3, and they each include a generally arcuate body section having a smooth bottom surface 47 disposed in a plane perpendicular to the axis of rotation of arm 7 with respect to arm 3. The smooth bottom surfaces 47 of the conductive shoes 43 and 45 are in electrical and mechanical engagement with the upwardly directed and resiliently biased looped ends 49 and 51 of a pair of associated

springs

53 and 55 to provide the two pairs of wiping contacts 37 and 39.

The

springs

53 and 55 have the general configuration of bent over hairpins. More particularly,

springs

53 and 55 each include the vertically arranged U-shaped loop 49 (FIG. 3) or 51 (FIG. 2) and a pair of supporting arms 49a or 51a (FIG. 3) which are bent over from their as sociated loops into a direction generally parallel to the longitudinal axis of arm 7. Each pair of the supporting 3 arms 49a and 51a is suitably secured into fixed electrical engagement with one of a pair of laterally spaced apart and elongated

conductive shoes

63 and 65 attached to the bottom surface of arm 7 near its end 31.

It will now be seen that two wiping connections are thus provided for the folding tone arm mechanism 1, by means of the resilient brush-type engagement of the looped ends 49 and 51 of the

springs

53 and 55 with the smooth surfaces 47 of the conductive shoes 43 and 45. When the

arms

3 and 7 of the tone arm mechanism are in the pivoted relationship wherein they are shown in FIG, 3, an electric circuit is thereupon established from the amplifier (not shown) to the pickup cartridge by means of a conductor 67 (disposed underneath arm 3), through conductive shoe 45, contact wiping spring 55, elongated contact shoe 65, conductor lead 69 (underneath arm 7),

terminals

71 and 73 of the pickup cartridge, conductor lead 75 (underneath arm 7), elongated contact shoe 63, wiping contact spring 53, conductive shoe 47, and conductor 77 (underneath arm 3).

The pickup cartridge 11 may be of any suitable variety. In the tone arm mechanism 1, which illustrates one embodiment of my invention, pickup cartridge 11 supports a drive rod 79 (FIG. 3) that carries a single stylus 81 (FIG. 2) on its bottom end. Cartridge 11 may be suitably secured to the bottom surface of arm 7 near its free end 13 by means of a V-shaped bracket 83 which has secured thereto a pair of gripping arms.

As further shown in FIG. 2, the tone arm mechanism 1 is readily operable with the

arms

3 and 7 in extended position (i.e. with their longitudinal axes generally aligned and the arms extended outwardly from each other) to reproduce the sound of a disc type of record 85 rotatably supported on a turntable 87. In the event that it becomes desirable to retract the arm 7, for the purpose of making the mechanism 1 more compact, arm 7 is simply rotated about its pivot with respect to arm 3 for approximately 180 degrees, until it underlies arm 3, as indicated in FIG. 6. The amplifier circuit to the pickup cartridge 11 is thereupon de-energized, since the

contact springs

53 and 55 are disconnected from their associated shoes 43 and 45. It will thus be realized that with a minimal effort, a relatively small tone arm mechanism is achieved, thus lending itself to convenient and expeditious storage.

FIGS. 4 and represent a modified form of my invention wherein tone arm mechanism 101 has been employed. For mechanism 101, the same reference numerals have been employed to indicate parts which have been described heretofore for mechanism 1.

Parts of mechanism 101 which have a modified structure in comparison to the structure of certain correlative parts for mechanism 1, but perform the same basic function, are identified by the same two reference numerals, with the numeral 1 prefixed thereto.

The basic difference between tone arm mechanism 101 and mechanism 1 resides in the fact that the

arms

3 and 7 of mechanism 101 are constructed of conductive material, While the

arms

3 and 7 of mechanism 1 are of insulative material. Since

arms

3 and 7 of mechanism 101 are conductive they are utilized in the amplifier circuit for the pickup cartridge 11, and consequently only one pair of wiping contacts 137 is required for the foldable tone arm mechanism. More particularly, arm 3 of mechanism 101 has a single enlarged arcuate conductive shoe 143 With a smooth bottom surface 147 for engagement with the spring biased looped end 149 of spring 153. Shoe 143 is secured to the underside of arm 3 near its free end 9, with an insulating spacer 144 located between the arm 3 and shoe 143. The spring 153 is similar in configuration, construction and arrangement to the

springs

53 and 55 and it functions, in the same manner. More particularly, spring 153 includes the looped end 149 and supporting arms 149a. The arms 149a are suitably secured to an arcuate outer surface of an enlarged conductive shoe 4 163. Shoe 163 is secured to the underside of the free end 31 of arm 7, but spaced therefrom by insulating. spacer 164.

When the

arms

3 and 7 of the tone arm mechanism! 101 are in the pivoted relationship wherein they are: shown in FIGS. 4 and 5, an electric circuit to pickup' cartridge 11 thereof is thereupon established from the amplifier by means of the series connection of conductivearm 3, conductive arm 7, arm terminal 166, lead 175,. terminals 173 and 171 of the pickup head, lead 169, con-- ductive shoe 163, spring 153, conductive shoe 143, and lead 167.

The tone arm mechanism 101 retracts in the samemanner as illustrated for mechanism 1, for convenient: storage, when it is not in operation.

It will now, therefore, be seen that my new and im-- proved foldable tone arm mechanism provides an effective Wiping contact arrangement. It will also be understood. that tone arm mechanisms embodying my invention are: of very compact structure, thereby readily lending them-- selves to efficient utilization for phonograph applications; requiring economy of space.

While in accordance with the patent statutes, I have described what at present are considered to be the pre ferred embodiments of my invention, it will be obvious. to those skilled in the art that various changes and modi' fications may be made therein without departing frommy invention, and I, therefore, aim in the following: claims to cover all such equivalent variations as fall within the true spirit and scope of this invention.

What I claim as new and desire to secure by Letters; Pattent of the United States is:

1. A folding tone arm mechanism for a phonograph,. said mechanism including a first element, a second ele-- ment, and a pickup cartridge; said first element supported for movement in vertical and horizontal directions rela-- tive to a normal position of said first element; and meansfor pivotally supporting said second element upon saidl first element for movement about a vertical axis to enable said second element to selectively serve as an ex-- tension from the free end of said first element for operation of said phonograph or to be folded back into com-- pact proximity with said first element when said phono-- graph is not in use; said pickup cartridge disposed upon. the free end of said second element; and means for con-- meeting said cartridge to said phonograph, said means; including at least one wiping contact on one of said ele ments for cooperative engagement with a mating contact: on the other of said elements, thereby to provide a fold-- able electrical connection to said pickup cartridge on said. tone arm mechanism.

2. The folding tone arm mechanism of claim 1 wherein the wiping contact is a generally V-shaped spring and. its mating contact is a relatively flat conductive shoe, said spring including a looped end biased into resilient. cooperative engagement with said shoe.

3. A folding tone arm mechanism for a phonograph, said mechanism including a first element, a second element, and a pickup cartridge; said first element supported at one of its ends for movement in vertical and horizontal. directions relative to a normal position of said first ele-- ment; means for pivotally supporting said second ele-- ment upon a free end of said first element for movement about a vertical axis to enable said second element to selectively serve as an extension from the free end of said first element for operation of said phonograph or to be folded back into compact underlying proximity with said first element when said phonograph is not in use; said pickup cartridge disposed upon the free end of said second element; and means for connecting said cartridge to said phonograph, said means including at least one wiping contact on one of said elements for discontinuous cooperative engagement with a mating contact on the other of said elements, thereby to provide a foldable electrical connection to said pickup cartridge on said tone. arm mechanism.

4. The tone arm mechanism of claim 3 wherein said first and second elements are of insulative material and said connecting means includes a pair of wiping contacts engaging a respective pair of mating contacts.

5. The tone arm mechanism of claim 3 wherein said first and second elements are constructed of conductive material and said connecting means includes one wiping contact for cooperative engagement with one mating contact.

6. The tone arm mechanism of claim 3 wherein the second element is generally parallel to the first element when said second element is in underlying proximity to said first element, said second element being rotatable upon said first element through an angle of approximately 180 from its normal operative position to its compact position.

References Cited by the Examiner UNITED STATES PATENTS 1,742,257 1/1930 Johnson et a1. 27423 2,116,050 5/1938 Stock et al. 240-73 2,595,621 5/1952 West et a1 310-232 3,120,393 2/1964 Pennucci 240-23 NORTON ANSI-IER, Primary Examiner.

C. B. PRICE, Assistant Examiner.

Claims

1. A FOLDING TONE ARM MECHANISM FOR A PHONOGRAPH, SAID MECHANISM INCLUDING A FIRST ELEMENT, A SECOND ELEMENT, AND A PICKUP CARTRIDGE, SAID FIRST ELEMENT SUPPORTED FOR MOVEMENT IN VERTICAL AND HORIZONTAL DIRECTIONS RELATIVE TO A NORMAL POSITION OF SAID FIRST ELEMENT; AND MEANS FOR PIVOTALLY SUPPORTING SAID SECOND ELEMENT UPON SAID FIRST ELEMENT FOR MOVEMENT ABOUT A VERTICAL AXIS TO ENABLE SAID SECOND ELEMENT TO SELECTIVELY SERVE AS AN EXTENSION FROM THE FREE END OF SAID FIRST ELEMENT FOR OPERATION OF SAID PHONOGRAPH OF TO BE FOLDED BACK INTO COMPACT PROXIMITY WITH SAID FIRST ELEMENT WHEN SAID PHONOGRAPH IS NOT IN USE; SAID PICKUP CARTRIDGE DISPOSED UPON THE FREE END OF SAID SECOND ELEMENT; AND MEANS FOR CONNECTING SAID CARTRIDGE TO SAID PHONOGRAPH, SAID MEANS INCLUDING AT LEAST ONE WIPING CONTACT ON ONE OF SAID ELEMENTS FOR COOPERATIVE ENGAGEMENT WITH A MATING CONTACT ON THE OTHER OF SAID ELEMENTS, THEREBY TO PROVIDE A FOLDABLE ELECTRICAL CONNECTION TO SAID PICKUP CARTRIDGE ON SAID TONE ARM MECHANISM.