US1951668A - Phonograph - Google Patents

Description

March 20, 1934. J. o. PRESCOTT PHoiqoGRAPH Filed March 9, 1931 2 Sheets-Sheet l INVENTOR B I, K ATTORNEY March 20,1934. J. o. PRESCOTT PHONOGRAPH 2 Sheets-Sheet 2 Filed March 9, 1931 =5 'I/IIIIIIIIIIII/IIIIII .M iii/1111111111111!!! M lllIIl I/IIIII INVENTOR \bH/V/ /RESCOT 7 BY 7 r V m ATTORNEY Patented Mar. 20, 1934 PHONOGRAPH .John 0. Prescott, Glenbrook, Conn., assignor to Columbia Phonograph Company, Inc., Bridgeport, Conn., a corporation of New York Application March 9, 1931, Serial No. 521,140

Claims. (Cl. 274-9) This invention relates to .new and useful improvements in phonographs or talking machines and has particular relation to automatic or multiple playing phonographs or to repeating 5 mechanism for phonographs.

An object of the invention is to provide a simple mechanical means for imparting to the reproducingstylus a slight tendency in a direction toward the beginning of the record groove of a phonograph record, the means being particularly adapted to cause a reproducing stylus to move into the first portion of the sound groove of a record when placed on the usual smooth portion of the record adjacent the beginning of the sound groove.

Other objects and advantages will become apparent from a consideration of the following detailed description taken in connection with the accompanying drawings wherein there is shown a satisfactory embodiment of the invention. -It is, of. course, to be understood that the invention is not limited to the details shown but comprehends all such variations and modifications as fall within the spirit of the invention and the scope of the appended claims to which latter reference must be had for a definition of the limitations of the invention.

The invention is shown as applied to a phonograph including an electric pick-up and pick-up arm but it will be understood that the invention is also applicable to phonographs employing an acoustic reproducer and a tone arm and that wherever in the following description and claims the words pick-up or pick-up arm are employed it is intended to include any type of pickup or reproducer for taking sound motion from a record and any type of arm 01' support.

In the drawings:

Figure l is a plan view of a pick-up arm and 40 pick-up, the arm being mounted in accordance with the present invention and the stylus of the pick-up being disposed on the smooth edge portion of a record;

Fig. 2 is a side elevational view thereof the arm mounting being shown in section;

Fig. 3 is a sectional view through the base of the arm the pivoting means therefor being omitted and showing the positionof my improved mechanism when the stylus is at the entrance to the first sound groove of the record;

Fig. 4' is a sectional view substantially at right angles to Fig. 3 and showing the relationship of the parts when the arm is arranged todispose the stylus on the smooth outer edge portion of a record;

Fig. 5 is a perspective view of the cam or button employed; and

Fig. 5 is an enlarged view of the button and screw shown in their relationship when a stylus is about to enter the first portion of a sound roove. I

Referring in detail to the drawings at 10 is shown a pick-up arm or support carrying a pickup 11 rigid with the arm and equipped with a stylus 12 which may be secured in place as by means of a screw. 13. As'before explained the arm 10 might well be a hollow tone arm and the pick-up 11 might well be an acoustic reproducer since the means of the present invention is applicable to either structure.

As shown, the arm 10 is pivoted at 14 for movement in a vertical plane, the arm being carried by the lug or block 15 on the upper side of a shallow dish-shaped member 16. Member 16 is mounted for turning movement in a horizontal plane and it will therefore be understood that arm 10 is capable of movement both horizontally and vertically. The means for mounting member 16 for turning movement includes a base member 17 secured as by ,bolts 18 to a motor board or other support 19, This board has an opening 20 to accommodate a depending pin 21 extending from the under side of the member 16 centrally thereof, the upper or inner end of the pin 21 being embedded in an enlargement 22 preferably although not necessarily formed with the member 16. a

Base member 17 includes a spider formed by the three arms 23 and at their adjacent ends these arms are connected by a hollow bearing '90 member 24 including 2. depending portion 25. It is through this member 24 that the pin 21 extends and this member 24' forms the pivotal mounting for the member 16. At its lower end the pin 21 extends beyond the bearing member 24 as clearly shown in Fig. 2 and secured on this extending or exposed portion of the pin as by means of a set screw 26 is a collar 27. The collar 27 is so positioned on the pin as to permit of slight vertical movement of the pin and member 16 10a and parts carried thereby relative to the base 17. The purpose of this arrangement will later be fully explained.

The lower edge of the base 17 rests on the edge portion of a plate or disc 28 which closes the'lOli lower side of the base and which has an opening 29 to accommodate the sleeve portion 25 of the bearing 24. This plate 28 is secured in place as by means of the bolts 18 which as previously explained secure the base 1'? to the motorboard lid or plate or other support 19. The means for mounting the pick-up for both vertical and horizontal movements has now been fully described and it will be understood that the stylus 12 carried by the pick-up 11 is to co-operate with a record 80, a portion of which is shown as disposed on a turntable 31 also fragmentarily shown, said turntable being mounted on a spindle 32 driven from any suitable source of power as for example, by means of a motornot shown.

It is already well known in the phonograph art and particularly as the same appertains to automatic or multiple playing phonographs to provide means for raising the pick-up or reproducer and its supporting arm at the end of the record and swinging the same out beyond the phonograph turntable either to permit a new record to be placed on top of the one which has just been played or to remove the played record and put a different record-in its provided for returning the reproducer or pick-up stylus to position toplaythe new record. Certain of thes'fineans when returning the reproducer or pick-up toward playing position deposit the stylus on the smooth outer edge portion of the record. The means last described, so far as I am aware, includes some spring means or complicated mechanisms for causing the stylus to move across the smooth outer surface of the record and into the initial portion of the sound groove.

According to the present invention simple mechanical means are provided for bringing about movement of the reproducing stylus across the smooth outer surface portion of a record after the stylus has been placed on'said portion. As herein disclosed, this means comprises a cam or button 33 including an inclined surface 34 and a substantially flat under-surface 35. The top surface 36 of the button is substantially flat and extending centrally from this surface is a threaded stud 37. To one side of the enlargement 22 the member 16 is provided with an elongated opening or slot to accommodate the stud 37 and when the stud is passed through this opening a suitable nut 38 is threaded onto the same to draw the flat surface 36 into engagement with the inner surface of the member 16. The button 33 is therefore adjustable toward and from the screw 40 to determine the amount of motion to be imparted to the pick-up arm 10 by the co-opcrating action of cam 33 and screw 40. Obviously, the nearer the fixedposition of stud 3'1 of cam 33 is to the screw 40, the greater will be the amount of lateral motion imparted to the pick-up arm owing to the riding of the point 41 of the screw on the inclined surface 34 of the cam. To assist in properly positioning the button 33 closer to the center of the member 16 when desired, it is cut away as at 39 and this cut-away I portion embraces a r )rtion of the enlargement 22 as most clearly shown in Fig.4.

Threaded through the plate 28 in line with the tapered or inclined portion 34 of the button or cam 33 is a screw 40. If desired, the plate 28 may be omitted and the screw may be passed through a lug (not shown) cast with the base 17. As best shown in Fig. 6 the screw has threaded engagement with the plate 28 and at its inner end the.

screw is rounded as at 41.- On the lower end of the screw is a nut 42 and disposed between this nut and the plate 28 and surrounding the screw is a sleeve 43. It will be understood that the screw may be adjusted through the plate 28 by first backing off the nut 42 and then engaging the slot place or to repeat the .played record. Also, various means have been 44 of the screw with a suitable instrument to turn the screw. The nut will after the adjustment be again tightened.

The operation of the improved device will probably be apparent. However, it may be briefly described as follows: Since the base 17 and plate 28 are rigidly connected to the motor board or support 19 they are stationary and the member 16 is turnable relative to them. The screw 40 is therefore held against movement while the button or cam 33 is movable as a unit with the member 16 which in turn is movable with the arm when the latter is moved horizontally.

Assuming that a record has been played and the arm raised and moved beyond the turntable and a new record placed on the turntable and the arm then moved to dispose the stylus on the smooth outer surface 45 of the record as shown in Fig. 1, my improved means for moving the stylus across this smooth surface 45 will function.

Its operation may probably best be described in connection with Figs. 3 and 4 and in Fig. 4 the parts are shown in the positions assumed by them when the stylus is on the outer smooth surface 45 of the record as shown in Fig. 1. In Fig. 4 it will be seen that the rounded or smooth end 41 of the screw 40 is in engagement with the inclined or tapered surface 34 of the button or cam 33 adjacent the lower edge of said surface and that the member 16 is spaced above the base the clearance being indicated at 46. Owing to the unstaple poise of the elevated member 16 and arm 10 and to the weight of the pick-up arm and block 15 and the like there is a natural tendency for movement to take place between the fixed screw and the movable cam 33 owing to the inclined surface 34. This tendency will be more fully understood when it is considered that the weight of the pick-up, pick-up arm and its mounting is all poised on the end of screw 40 which is, of course, in engagement with the inclined surface 34 of the cam or button 33. Such tendency is translated into a rotary movement imparted to the member 16, the movement of this member resulting of course in movement of the arm 10, pick-up 11 and stylus 12 carried by the pick-up, the stylus being moved across the surface of the record and into the initial portion of the sound groove thereof. i

The movement just described results in a lowering of the enlargement 22 of the member 16 onto the bearing 24 on the base 17 and in Fig. 3 the relative position of the parts is shown at the Here it will be seen that the member 16 has been lowered onto the base 17 and that the smooth or rounded end '41 of the screw 40 is about to leave the inclined surface 34 of the cam or button 33. This relationship between the screw and cam is also shown on an enlarged scale in Fig. 6. Of course, when the arm 10 is again moved to dispose the plck-up beyond the edge of the record in order that a'new record may be placed on the turntable the parts will again be disposed in the relative positions shown in Fig. 4 when the arm is moved inwardly to dispose the stylus 12 on the smooth outer edge portion of the unplayed record.

While the invention has been described as relating particularly to automatic phonographs of the multiple playing type it will be understood that it is equally applicable to an automatic repeat mechanism since the function of the invention is to bring about movement of the stylus across the smooth outer edge portion of a record portion of the record and to then slide the stylus inwardly as by following this method it is certain that the stylus .will not be engaged with the record at a point inwardly of the beginning of the sound groove.

Particular attention is called to the fact that I have provided an extremely simple mechanism for accomplishing the desired object and that the mechanism is entirely mechanical and does not include springs or other parts which may'get out of order due to repeated use or to rough usage.

Essentially, my improved mechanism includes only the button or cam 33 and the screw 40.

Having thus described the invention, what is claimed is:

1. In a phonograph, a horizontally disposed turntable, a pickup arm carrying a pickup for cooperation with a record on said turntable, said ickup being pivotally mounted on horizontal axis so that weight thereof tends to drop said pickup on a record, a motor board, a mounting means on said board for carrying said pickup arm, said mounting means including a vertical pivot around which said pickup and arm may move in a horizontal plane, and means including a cam and follower therefor for supporting the weight of said mechanism normally resting on said vertical pivot only for the position of said pickup arm corresponding to the position of the pickup stylus when in engagement with the smooth outer portion of a record, said cam being tionary.

4. In a phonograph, a horizontally disposed turntable, a pickup arm carrying a pickup for cooperation with a record on said turntable, said,

pickup being pivotally mounted on horizontal axis so that the weight thereof tends to drop said pickup on a record, a motor board, a mounting means on said board for carrying said pickup arm, said mounting means including a vertical pivot around which said pickup and arm may move in a horizontal plane, the mounting means also including a button shaped cam eccentric with said vertical pivot and movable thereon with said pickup arm, a fixed stop cooperating with said cam, said stop and cam being so related to each other that the weight of said pickup arm is borne by said stop for the position of the pickup arm corresponding to the position of said pickup stylus when in engagement with the smooth outer portion of a record only, the weight of said pickup arm tending to move said pickup arm inwardly toward the grooved portion of the record and being released from said cam at the end of such movement.

5. The structure of claim 4, wherein the eccentricity of said cam may be adjusted in respect to the position of said vertical pivot.

JOHN O. PRESCOTT.

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