US2402150A - Phonograph tone arm mounting - Google Patents

Description

June 18, 1946. c. B. DALE PHONOGRAPH TONE ARM MOUNTING 2 Sheets-Sheet 1 Filed Aug. 30, 1945 June 18, 1946.

c. B. DALE PHONOGRAPH TONE ARM MOUNTING Filed Aug. 30, 1943 2 Sheets-Sheet 2 will!!! v v v r v r z 1/ A Patented June 18, 1946 PHONOGRAPH TONE ARM MOUNTING Colin B. Dale, Oak Park, Ill., assignor to Webster- Chicago tion of Illinois Corporation,

Chicago, 11]., a corpora- Application August 30, 1943, Serial No. 500,483

, 1 This invention is directed to the means provided for mounting a phonograph tone arm in such a way as' to permit it to swing inwardly under the guidance of the needle which engages the record groove of a, disk without appreciable restraint due to friction in the bearing which supports the shaft upon which the tone arm is pivoted. This result is attained by employing but a single point bearing for the lower end of the shaft which is subjected to a direct vertical thrust under the weight of the tone arm, so that, while playing, side bearing pressures are eliminated together with all friction or cramping occasioned thereby. This method of support not onl avoids wear on the parts and simplifies the construction, but also prevent mechanical noises in the tone reproduction and reduces wear on the record line.

Further objects and details will appear from a description of the invention in conjunction with the accompanying drawings wherein:

Figure 1 is a sectional detail showing those portions of a record changing phonograph which relate to the construction andoperation of the present invention; and

Figs. 2, 3, 4 and 5 are sectional details showing the tone arm and its stages of adjustment, 1

The tone arm with its mountings and associated mechanisms is here shown as embodied in the structure of a record changing phonograph which is the subject or a patent application filed of even date herewith, but it will be understood that the present invention is capable of general employment in connection with phonographs, and that its use is in no way conditioned by the presence or absence of record changing features or of special mechanisms employed for imparting rotation to the turntable, or other features not having special relation to the tone arm and its mountings. It will therefore be understood that any disclosure of such additional features serves merely to illustrate one type of phonograph with which the present invention may be advantagecusly employed, and is not to be regarded as a limitation on the more general use to which the invention is adapted. I

As shown, the tone arm it is in the form of an elongated channel-shaped stamping having side flanges ii, an inner end wall I2, and an outer end wall It, The inner end houses the mounting for a needle It which may be of any conventional type, or which may have connection with a radio amplifier or equivalent construction.

mountings in successive 8 Claims. (Cl. 274-423) The needle features are standard and need not be described in further detail.

The tone arm near its outerend has secured to its under facea bracket l having depending cars It which carry a horizontal pintle l1 upon which the ears are pivoted, so that the tone arm will have freedom of pivotal movement in a vertical plane but must swing laterally in unison with the mounting bracket l8. Themounting bracket is fixed upon the upper butt end of a Vertical shaft I 9 which is supported through aligned guide apertures and 2!, respectively, in the top wall 22 of a standard 23 and in a base plate 24 to which the standard is affixed. The standard has side walls 25 and an upstanding tongue 26 termihating in a stop flange 2'! which coacts with a hooked finger 28 depending from the tone arm near its outer end and beyond thepintle on which the arm is pivoted. The connection between the hooked finger and the stop during various stages in the lifting of the pivoted end of the tone arm is i lustrated in Figs. 2, 3, 4 and 5.

The lower end 29 of the vertical tone arm shaft is of pointed or conical formation, and is supported in thrust bearing contact upon the outer end 30 of a lever 3! fulcrumed at 32 upon a hanger 33 depending from the base plate. The inner end of the lever is upturned and carries a roller 33 which engages a cam track 34 on the lower face of a cam disk 35 journaled upon a stub shaft 36 depending from the base plate. The, cam track has formed therein a notch 31 which is normally in register with the roller 33 duringthe playing of a record while the thrust of a spring 38 holds the outer end of the lever in lowered position and with it the tone arm shaft which lowers the hooked finger 28 sufficiently to break engagement with the stop flange 21; This is the position shown in Fig. 1 wherein the tone arm is free to follow the record line while supported only by the needle at its inner end, and by the vertical shaft with its cone bearing near its outer end. The thrust on the shaft is directly downward so that no side pressure is exerted against the sides of the apertures 20 and 2! which thus serve merely as guides to position and steady the shaft without serving in any true sense as bearings, so that frictional contact therewith is negligible.

The periphery of the cam disk is provided with spur teeth 39 which, while in train with a pinion 40 on the constantly rotating spindle 4t upstanding from the center of the turntable 42, will impart a single rotation to the cam disk to elevat/e the tone arm in preparation for its outward acoaieo swing to afi'ord clearance for the positioning of a record disk, and the clearance will he maintained during the inswing of the tone a until the needleengages the low pitched record groove.

The outswinging of the tone arm may be per formed manually or automatically, as described in the companion application aforesaid, or in any other desirable or convenient manner, and it is not deemed necessary to here describe such ice.- tures, which form no essential part of the present invention; The same is true as regards the means provided for constantly rotating the turnm cle with its spindle, the means for automatically releasing record disks when such means are com ployed, the means for temporarily entraining the cam dish with the constantly rotating pinion on the turntable spindle during the record changing operations and other associated operations, all of which may be performed automatically in timed sequence as set forth in the companion applica= tion aforesaid, but are not required when single records are manually positioned and removed.

Operation of the lever, which may be manually operated or controlled by automatic means of any suitable character.

When it becomes necessary to change record disks the lever, or other equivalent means, will be shifted to elevate the tone arm shaft which thus imparts a thrust against the outer end or the tone arm which lorings the linger into engagement with the fixed stop 2i (as in Fig. 3) so that a. continuing upward thrust will elevate the inner free end of the tone arm to the position shown in Fig. i, thereby affording clearance for the removal of a played record and the positioning of a new one.' It will be seen that it is only during the record changing interval that the tone arm is in any way restrained inits free swinging movements, and that during the playing interval it is free to follow the record line without any restraint due to friction or cramping in the tone arm mountings.

Although the invention has been described with particularity, it will he understood that various modifications in detail may be made without departing from the spirit of the invention.

I claim:

1. in a tone arm mounting, in combination with a turntable, a tone arm adap to carry a needle at its inner end, a vertical tone arm shaft, connections between the outer end portion of the tone arm and the shaft adapted to permit pivotal movement of the tone arm in a vertical plane and to impart a vertical thrust upon the shaft, a vertically adjustable support for the lower end of the shaft afiording a tt hearing therefor, a member contacting the side of the shaft in a manner free irom hearing thrusts and adopted to steady the shaft and maintain it in vertical position and means for restraining the outer end of the tone arm beyond the aforesaid connections, and adapted to cause an angular uplift of the inner end or the tone when the verti short u raised. 1

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point thrust hearing therefor, a member contactingthe side of the shaft in a manner free from hearing thrusts and adapted to steady the shaft and maintain it in vertical position and means for restraining the outer end oi the tone arm beyond the aforesaid connections, and adapted to cause an angular uplift of the inner end or the tone arm when the vertical shaft is raised.

3. In a tone arm mounting, in combination with a turntable, a tone arm adapted to carry a needle at its inner end, a vertical tone arm shaft, connections between the outer end portion oi the tone arm and the short adapted to permit pivotal movement of the tone arm in a vertical plane and to impart a vertical thrust upon the shaft, a vertically adjustable support for the lower end of the shaft afiording a thrust hearing therefor, a member contacting'the side oi the shaft in a manner free from hearing thrusts and adapted to steady the shaft and maintain it in vertical position, a stop memher on the outer end of the tone arm beyond its point of support on the shaft, and a fined stop member in adjacent relation thereto and adapted to engage the tone arm stop member during the liiting of the shalt to restrain the outer end of the tone arm while continuing upward movement of the shaft liftsthe free inner end of the tone arm.

4.111 a tone arm mounting, in combination with a turntable, a tone arm adapted to carry a needle at its inner end, averticsl tone arm shaft, connections between the outer end portion of the tone arm and the shaft adapted to permit pivotal movement oi the tone arm in a vertical plane and to impart a vertical thrustupon the shaft, a vertically adjustable support tor the lower end of theshait afi'ording 0. single conical point thrust hearing therefor, a member con tacting the side of? the shaft in a manner free from hearing thrusts and adapted to steady the shaft and maintain it in vertical position, a stop memher on the outer end oi the tone arm beyond its point oi support on the shaft, and a hired stop member in adjacent reletionthereto and adapted to engage the tone arm stop member during the lifting of the-short to restrain the outer end oi the tone arm while continuing upward movement oi the shaft lifts the free inner end of the tone arm.

5. In a tone arm mounting, in combination with a turntable, a tone arm adapted to carry a needle at its inner end, a vertical adjustable tone arm shaft and a member aflording lateral non-frictional guiding contact therewith during vertical adjustment, bracket connections between the outer end portion of the tone arm and the shaft including a horizontally disposed pintle upon which the tone arm is pivoted near its outer end to permit movement in a vertical plane, said mountings being adapted to impart a vertical thrust upon the shaft, a lever one end of which oflords a single conical point thrust bearing for the lower end of the shaft, 9. hooked stop linger depending from the outer end oi the tone arm beyond its pivotal mounting, and a fined stop member in adjacent relation thereto and adapted to engage the stop finger during the lifting of the shaft to restrain the outer end of the tone arm while continuing upward movement oi the shaft lifts the free inner end of the tone arm.

6. A tone arm mounting for phonographs and the like including a fixed support member, a spindle extending vertically therethrough, a tone arm adapted to carry a needle at its inner end and at its outer endsupported during play solely by pivot means having a generally horizontal axis approximately intersecting the axis of the spindle whereby the weight of the tone arm car ried by the pivotal support member during play is received by the spindle as an axial thrust, tilt means disposed to engage the tone arm at a point spaced from the axis of the spindle and from the inner end of the tone arm, and means to produce relative motion between the spindle and the tilt means in a direction axial of the spindle to raise the inner end of the tone arm from a record.

7. A tone arm mounting for phonographs and g the like including a fixed support member, a

spindle extending vertically therethrough, a tone arm adapted to carry a needle at its inner end and at its outer end supported during play solely by' pivot means having a generally horizontal axis approximately intersecting the axis of the spindle whereby the weight of the tone arm carried by the pivotal support member during play is received by the spindle as an axial thrust, and means spaced from said pivotal support eilective upon axial movement of the spindle for restraining the tone arm to cause a tilting action of the tone, arm about the. pivotal support.

8. A tone arm mounting including a rigid supporting member, a spindle mounted thereon for axial movement and for rotation about a generally vertical axis, generally horizontal pivot means carried by the spindle and adapted to pivotally support the outer end of a tone arm therefrom and restraining means carried by the rigid support and adapted to restrain the tone arm at a point more remote from the axis of the spindle than the horizontal pivot means to cause a tilting of the tone arm upon axial movement of the spindle, the outer end of the tone am being supported during play solely by said pivot means.

COLIN B; DALE.

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