US2346733A

US2346733A - Tone arm

Info

Publication number: US2346733A
Application number: US462276A
Authority: US
Inventors: Dally Roy
Original assignee: Webster Electric Co Inc
Current assignee: Webster Electric Co Inc
Priority date: 1941-01-18
Filing date: 1942-10-16
Publication date: 1944-04-18
Anticipated expiration: 1961-04-18

Description

April1s,1944. n. DALLY 2,346,733

ATom: ARM

original Filed Jan. 18.v 1941 atentedy Apr. 1 8, 19,44 i

UNITED STATES PATENT OFFICE naar:

Original application January 18, 1941, Serial No.

^ A 374,984. Divided and this application October 16, 1942, Serial No. 462,276

ha a pickup"provided with a chuck having a stylus securing screw, the head of which is suitably concealed inside the tone arm, but

which is adapted to be uncovered for engagement with the screw driver.

other obiect of the invention is the proon oi an improved handle structure for use in lifting the tone tf-sf to remove it from a record or place it on a record.

Another objectv oi' the invention is the provision ci an improved handle structure for tone arms, which is also apted to be removed from l the tone t' n for the stylus securing screw whereby -the screw may be concealed, yet made accessible 'tosthose who are familiar with its location and with the structure 'of the tone Another object of the invention is the provision oi an proved tone arm having a removable handle, which is adapted to permit the tone arm to be lifted more conveniently for application to a record or removal from a record.

The present application is a division of `my prior application, Ser. No. 374,964, on Tone arms, led January 18, 194i, now Patent No. 2,313,126,

, i granted March 9, i943.

other objects and advantages of the invention will be apparent from the iollovdescription and the accompanying drawing, in which similar characters -of reference indicate similar parts throughout the several views.

Referring to the single sheet oi' drawings,

Fig. l is a top plan view oia phonographv equipped with a tone arm embodying my invention;

Fig. 2 is a fragmentary sectional view, taken on the plane of the line 2 2 of Fig. 1; i

Fig. 3 is a e uw plan view of the tone arm I structure, with the lower pickup parts removed,

sho the structure of the handle forthe tone of which the tone arm is mounted for substantially universal movement, so that it `can be lifted from the record and so that it can progress across the record as its needle follows the groove in the record 2t;

The tone arm is preferably of a channeled construction, having an upper wall 2t (Fig. 6)

and a\ pair of depending side walls i8 and 2i Joinedby the partially cylindrical corner portions lt. Atits rear or pivotally supported end, it has an end wall il, closing the end of the channel and Joined to the top wall 25 by a partially cylindrical portion it.

The iree end of the tone arm is preferably provided with an enlargement for receiving the crystal pickup, and this enlargement is bordered by a depending wall it, which may be substantially cylindrical at the end ld of the tone arm.

In the particular embodiment selected to illustrate the invention, the tone arm has formed integrally with it the half housing iii, which forms the upper part of the crystal pickup, the lower Ihall housing being of metal, indicated at di.

Other orms of pickup may also be employed,

and the handle may also be utilized on other forms of tone arms.

The pickup is provided with a chuck d2, having a threaded bore di for receiving a threaded screw boltdit. The bore t3 communicates with the stylus socket db, which is adapted to receive the shank of the stylus t6. The stylus is secured in place by means of the screw bolt M, the head of which has a suitable socket til. The socket may bea slot for an ordinary screw driver, or a cruciform slot for special screw drivers.

In the preferred form of the invention the 'chuck has a thrust bearing d@ engaging a com- `driver on such a delicate instrument is that too much force will be applied, and the` present tendencyis toward the use of permanent styli which are not intended to be removed by the ordinary user of the tone arm.

Thus it is desirable that the head 52 of the screw be concealed, yet accessible for removal of the stylus, if it is absolutely necessary.

For this purpose the end wall 39 is provided with an upwardly extending slot 5t, having parallel side walls; and this slot is of suillcient Widthto pass the shank of a small screw driver engageable in the socket di of the head 52 of the screw bolt de.

The slot 53 may be closed by means of the handle 54. The handle 5t may comprise a cast metal member or a member molded of a phenolic condensation product, or other suitable material.

It is provided with a securing portionlii and a finger engaging portion 56. The nger engaging portion EB is preferably concavely curved on its lower side at 5T, and is convexly curved at 58 `on its upper side.

The upper side may have a reinforcing rib E@ bordered by longitudinally extending curved or grooved portions SB, el. The extreme end portion t2 may be reversely curved to extend upward, and all the portions of the handle @d are preferably slightly rounded. v

The securing portion of the handle, comprising a substantially rectangular portion 5b, has a pair of parallel slots 63rd@ on the opposite sides of this portion. The slots 63, ad are wide enough to receive the end wall 239, and the body portion between the slots is slightly less than the width of the slot 53 in the end wall.

Thus the handle securing portion 55 may be slid upward in the slot 53, and the wail portions 39 will extend into the slots 63, dit. The handle should have such a fit that it is frictionally held in place.

It will thus be observed that this handle may be conveniently removed whenever it is desired by the repairman or the manufacturer of such tone arms, and the stylus may be secured or removed, but the stylus will ordinarily not be disturbed by the user of the tone arm.

The handle is adapted to-be used for lifting the tone arm by placing one or two fingers under it, and there is less likelihood of the tone arm being dropped than if no handle is provided.

Unauthorized persons will not ordinarily tamper with the stylus or try to change it under these conditions, and it is believed that better service may be secured by having these parts accessible only to those familiar with 'the tone arm. Thereis less likelihood ofV sumcient axial force being placed on the screw vto damage the crystal.-

In the embodiment illustrated such forcey is resisted by the thrust bearings, but the present handle and tone arm structure may .be used upon pickups not `having thrust bearings.

While I have illustrated a preferred embodiment of my invention, many modications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but desire to avail myself ofall changes within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

assenso producer unit carried by the free end of said tone arm with a channeled member of molded insulating material having depending side and end ilanges, the flange at the free end of said tone arm having an inwardly extending slot open at its lower end, and a handle having a body receivable in said slot and having thrust surfaces engaging on the inside and outside of said tone arm.

2. In a tone arm, the combination oi' a channelled tone arm member having a downwardly open socket at its end for receiving a pick-up unit, with a pick-up unit in said socket, said pick-up unit having a chuck provided with a stylus socket, and having threaded means for engaging a stylus in said socket, said tone arm being formed with an aperture in its side wall opposite said threaded means for passage of a tool, and means for closing said aperture, comprising a removable handle adapted to be securedl in said aperture, said aperture having parallel walls and being open at the bottom, and said handle having a siidable portion for engaging the edges of said walls in said aperture, and said handle having oppositely located slots for receiving the wall portions adjacent said aperture.

3. In a tone arm, the combination of a tone arm comprising 'a channelled member having depending side and end anges, and the flange at the free end of said tone arm having an upwardly extending slot open at its lower edge, with a handle member comprising an outwardly extending iinger piece adapted to be engaged by the fingers, and a securing body, said securing body having formed on its opposite sides a pair of vertical slots, said slots being of sufcient thickness to receive said depending flanges at the side, the'tlanges of said tone arm at said upwardly extending slot, and to be secured to said tone arm by frictional engagement.

4. Ina tone arm, the combination of a tone arm comprising a channelled member having dey pending side and end flanges, and the flange at 1. In a tone arm, the combination of a rethe free end of said tone arm having an upwardly extending slot open at its lower edge, with a handle member comprising an outwardly extending finger piece adapted to be engaged by the fingers, and a securing body, said securing