US2236599A - Pickup arm - Google Patents

Description

W. H. HUTTER PICKUP ARM April l, 1941.

Filed Aug.

6, 1938 2 Sheets-Sham; 1

April l, 1941- w. H. HUTTER 2,236,599

PICKUP ARM Filed Aug. 6, 1938 2 Sheets-Sheet 2 Patented Apr. l, 1941 PICKUP ARM j William H. Hutter, Chicago, Ill.

Application August 6, 1938, SerialNo. 223,442 l 7 Claims. (Cl. 274-23) My invention relates to an improved pickup arm and to an improved mounting therefor.

For clarity, it is pointed out that two types of vibrations are discussed herein. First, reproducing vibrations, which are those desired, and which emanate from the orderly undulations in ,a record groove. These vibrations are transmitted to the needle and its mounting and are preferably coniined thereto to give the desired reproduction. Second, resonant vibrations, which are undesirable and which are those emanating from Wave impulses created by reproducing vibrations in the speaker or by vibrations originating externally of the system. These resonant yvibrations emanating from the speaker are often in the form of unorganized clicks having no denite range or tone. When the resonant vibrations react in the cabinet or upon the external system of the instrument, `and are of low frequency to be strong enough to effect a vibratory response in the head and arm, they create distortion of the normal, desired reproducing vibrations in the needle by setting up a vibratory response in the external system of the cabinet and -upon the pickup arm. 'I'his phenomenon is referred to herein as acoustic feed back and will be discussed more fully hereafter.

Among the more important objects of my invention is the provision of an improved device of the above character which gives better and truer sound reproducing qualities by preventing the acoustic ieed back above mentioned; by preventing both twisting and lateral vibratory movements in the arm, particularly the head, thereby confining the record produced vibrations to the needle and preventing their absorbtion and dissipation by independent movement of the arm; and by attaining the above objects without imparting added weight to the needle carrying end of the arm. Furthermore, the arm is rugged in that it is yieldably, swivelly mounted on its base through a single joint whereby the arm may be jarred or may be subjected to abnormal abusive movements without the joint or bearing becoming impaired.

Another object of the invention is to provide a pickup arm having a needle bearing head, an intermediate arm portion and a rear mounting portion formed integrally with one another or associated in rigid immovable relationship to constitute a substantially integral unit.

In the operation of a pickup arm two essential movements are involved, first, it is necessary that the head be raised and lowered about the rear end to permit the needle to be changed, to permit the return of the head from the center to the periphery of the record after it has been played, and to permit the head to rise and drop during playing if the record is Warped or the l turntable is out of line with its rotating axis.

Second, it is essential that the head of the arm move through a horizontal arc vabout the rear mounting end in order that the needle may follow the usual spirally cut groove in the face of the'record,

Heretofore theabove movements have been accomplished by the provision of a pivot having a vertical axis, at therear end of the arm, and by a pivot having a horizontal axis, intermediate vthe length lof the arm. With such a construction several disadvantages are experienced, namely, the arm proper is divided into a plurality of relatively movable parts, which relative movement enhances the possibilities of twisting or vibration of the arm proper, especially after the bearings at the joints have become worn in the slightest degree; the joints bind to lock the arm against the required movements; the arm and its parts become out of center; the arm may be broken by rough usage and extraneous sound is introduced because of acoustic feed back and the condition known as chatten The above disadvantages are considerably reduced by the provision of the above mentioned rigid pickup arm. Therefore it becomes necessary to provide improved mounting means Whereby such an arm is movable with the same or more iiexibility than is an arm having a plurality of joints therein.

To accomplish the above and as another object of the invention I have provided an improved mounting for a pickup arm in the nature of a swivel joint.

Still another object of the invention is to provide a mounting of the above character which is held yieldably to its base whereby it Iis capable of withstanding abusive treatment without the connection becoming impaired.

Still another object of my invention is to provide a mounting of the above character Which is constructed in such a manner that its stance on the base or With the base is sufficiently solid to resist the tendency of the arm to twist about its longitudinal axis underv the inuence of lateral vibratory motion of the needle.

It is to be understood that the term rigid is here applied to the arm represented by that portion of the pickup assembly extending from the head portion rearwardly tothe connection with support or cabinet.

Heretofore it has been the general opinion that absolute freedom of horizontal movement is necessary at the pivot point provided on a pickup arm, to permit the outer wall of the record groove to urge the head through its arcuate movement with the greatest possible ease, thus reducing the wear on the groove. This concept, it will be readily understood, carries with it the disadvantage that, because of this freedom of movement, the arm is increasingly responsive to the vibratory movement imparted to the needle and therefore absorbs some of the reproducing vibration therefrom. For maximum efficiency of operation, this vibratory movement should be conned to the needle and its mounting. Increased mass has been provided in the past to afford inertia to overcome this disadvantage, however, the inertia produced by the weight has been relatively ineffective to maintain the arm stationary against the record produced vibrations because of the presence of the freedom of movement thought to be necessary. A mass great enough to afford the required inertia in the presence of such freedom of movement, to prevent absorption of reproducing vibrations by the pickup arm, has been found too cumbersome and voluminous for ordinary commercial use.

Consequently, another object of my invention is to provide an improved pickup arm mounting in which the bearing of the mounting or pivot portion of the arm moves over a relatively resistant or friction surface.

Another object of my invention is to provide a mounting of the above character in which a mass is located at the mounting or pivot end of the arm, the weight of this mass being great enough to resist movement of the head and shank of the arm under the inuence of vibratory motion of the needle and its mounting, and under the inuence of acoustic feed back or the lowest resonant vibrations developed within the instrument as a whole. This mass, or its inertia, in combination with the frictional resistance of the bearing on the base, is very eiective to maintain the normally swivelly mounted arm stationary in spite of the vibratory motion of the needle in the head. Furthermore, it will be seen that the additional impedance to vibratory movement of the arm, afforded by the friction, permits a considerable reduction in the weight and volume of the mass used. It is to be noted that to be most effective for the above purpose, the impedance of the combination of friction and inertia at the rear of the arm, to the vibratory motion, must be greater than that between the needle mounting and the head. Under these conditions, record produced vibratory motion is confined to the needle and its mounting and such motion is therefore not absorbed by the arm.

During rotation of the record, the head is progressed from the periphery of the record toward the center thereof by the sliding abutment between the outside of the needle point and the outer wall of the spiral groove. This sliding abutment detracts from maximum freedom of movement of the needle in the groove under the influence of the lateral undulations therein, and furthermore, the wear on the abutting wall is considerable.

To obviate this condition and as another object of my invention, I have provided a mounting for a pickup arm which includes yieldable means for placing tension on the arm and head and for urging the head toward the center of the record, thus relieving the wall of the groove of needle.

a considerable part or all of its guiding action. This yieldable means may be constructed to be adjustable whereby the tension exerted may be regulated. It will be seen that this tension is of further value because it overcomes the resistance to arcuate horizontal movement of the arm introduced by the above mentioned friction surface.

Still another object of my invention is to provide a pickup arm of the above character having mass added thereto but which nevertheless has a relatively light head portion, thereby ensuring maximum playability and tone quality. The weight pivots, rather than rotates, about the pivot or swivel at the rear end of the arm to eliminate exing thereof throughout its length.

It is well known that a reduction in the downward pressure of the needle point into the record groove, `in other words, a reduction in the weight bearing down upon the head of the pickup arm, improves the quality of reproduction through the However, if the base upon which the instrument sets is vibrated to any great extent, as by dancing, the light head responds by -jumping from the groove and otherwise distorting the reproduced sounds. Consequently it is desirable that some means be provided to compensate for varying conditions in the base upon which the instrument is set.

To this end and as another object of my invention I have provided a pickup arm having means for regulating the degree of pressure with which the needle is set in the groove during playing. This adjustment is accomplished herein by placing a weight at the pivot end of the arm, which weight may be moved at will toward and away from the head, with the result that the downward pressure at the head is varied accordingly.

Many other objects and advantages of my invention will become apparent from the following description and accompanying drawings, in which:

Fig. 1 is a side elevation, partly in cross section, of an embodiment of my invention;

Fig. 1A is a fragmentary side elevation of a modied form of mounting shown in Fig. l;

Fig. 2 is a top plan view of Fig. 1;

Fig. 3 is a section taken on the line 3 3 Fig. 1;

Fig. 4 is a section taken on the line 4-4 Fig. 1;

Fig. 5 is a section taken on the line 5 5 Fig 3;

Fig. 6 is a section taken on the line 6-6 Fig. 3;

Fig. 7 is a side elevation of a modification the mounting shown in Fig. l;

Fig. 8 is a perspective of a modified form of mounting; and

Fig. 9 is a diagrammatic view of a complete reproducing instrument having a pickup arm of the character here disclosed mounted therein.

It is to be understood that the embodiments disclosed herein, while preferred, are illustrative and may be changed or modified without depart ing,r from the spirit and scope of my invention set out in the appended claims.

As previously stated, rigidity throughout the length of the pickup arm eliminates the possibility of vibratory action of the needle being absorbed by twisting of the head portion in response to the vibration. Furthermore, extraneous noises such as chatter resulting from loose joints are greatly reduced or eliminated with such a construction. Consequently, as shown in Fig. 1, the arm constitutes generally a head portion Ill carrying a needle II, the former being rigidly associated with an arm or shank I2 (integral therewith in the present instance) having a rear pivot or mounting portion I3. The foregoing assembly is mounted upon a cabinet or the like, a fragment of which is shown at I4, in a manner to be described presently, while the usual turntable I5 carryingl a spirally cut record I6 is positioned beneath the head.

The mounting assembly shown in Fig. 1 constitutes generally a weight or inertia element Il', to the upper surface of which, in the embodiment shown, the rear pivot or mounting end lI3 of the arm I2 is secured as by screws I8. This inertia member I'I is 'adapted to move with the arm throughout its horizontal, pivotal movement and throughout its vertical, pivotal movement. Consequently a suitably rounded, smooth riding, bearing surface is provided on its bottom side, as shown at I9.

A suitable friction surface upon which the bearing surface I9 of the inertia member II may ride, is provided on the upper surface of the cabinet, which is apertured as shown at 20 immediately beneath the mounting member. This friction surface constitutes, in the present embodiment, an apertured plate 2| which is secured,

as by screws 22, to the upper surface of the cabinet over the aperture 20. The plate 2l, in turn, hasI an apertured, centrally disposed, piece of friction material such as leather or felt, shown at 2Ia, suitably secured on its upper face, an annular, centrally located portion of the friction surface 2 Ia being adapted to extend inwardly beyond the edge of the aperture in the plate, thereby to provide a sound insulating abutment for the mounting connection to be described presently. Consequently, the pickup arm may be moved vertically about the surface I9 or it may move horlzontally about its rear mounting portion by the sliding engagement of the surface 2I a and the surface'IS. In effect a swivel or universal joint is provided.

It is to be noted that the weight II is substantially centered or concentrated about the vertical pivot for vthe arm as distinguished from being mounted on one or the other side thereof longitudinally of the arm. Thus the weight pivots about this axis rather than rotating thereabout. This reduces and substantially eliminates flexing of the arm throughout its length under influence of the inertia created.

In order to protect the above connection from breakage by violent movement of the arm or from impacts, it is desirable to avoid the use of positive mechanical connections for securing the arm to the cabinet I4 and to make such connection yieldable. As shown in Fig. 1, this is accomplished herein by boring the inertia member II as shown at 23 in order that it may receive a coiled spring 24, the upper end of which extends through an aperture in the lower side of the arm I2 and is secured thereto in non-rotatable relationship by having its end 25 bent downwardly to pass through a slot or additional aperture therein, as shown in Figs. 3 and 4. The lower end of the spring 24 extends downwardly through the inertia member I'I, the felt Zia, the plate 2l, and into the aperture 29 in the cabinet top, where it receives at its lower end a ferrule 26 to which its lower end is non-rotatably attached as by extending the bent portion 2l thereof upwardly into a suitable hole in the lower surface of the ferrule. As shown in Fig.'3, the upper face of the ferrule 26 has a circular series of posts 28 protruding therefrom, which posts coincide with and are received by a series of bores 29 drilled into the lower face of the plate 2|. A suitable conduit 30 extends from the sound box in the head of the arm which is preferably tubular, rearwardly through the shaft or arm I2, which is also preferably tubular, downwardly through the spring 24, to a suitable amplifier 3| shown in Fig. 9. A less desirable yet satisfactory construction is shown in Fig. lA where the swivel connection is afforded by an arcuate hollow member 24a which passes through plate 2I and felt 2Ia and is adapted to rotate therein with the horizontal movement of the arm and to slide therethrough to permit vertical movement thereof. A spring 24h affords the resiliency of the connection.

With the foregoing constructions it will be seen that I have provided a swivel mounting for the pickup arm which, additionally to its swivel characteristic, is maintained by means of a yieldable element such as the spring 24. Thusit is found that the arm I2 may be grasped and twisted or pulled violently, and that after such treatment, upon release, the mounting returns to its normal operative position under the influence of the springs and has not been impaired. Furthermore, it will be seen that this flexible mounting is attained through a single joint as compared to the plurality of joints heretofore utilized in order to get both horizontal and vertical movement. It will be seen that no mechanical, precision bearing joints are utilized, but instead the mounting element of the arm is merely set for free bearing movement on the upper surface of the cabinet. It will be seen therefore that the junction between the cabinet and the arm is such that shock resulting from abusive treatment, such as violent impacts, to the cabinet, will notimpair the operability of the swivel joint.

As previously stated, a mounting of the character shown in Fig. 1 is additionally advantageous in that the spring is non-rotatably secured to both the arm and the cabinet (the latter being through the post connection of the ferrule and the end 2l' of the spring therein). It will be understood that the spring 24 not only exerts a tension force to hold the inertia member I1 against the friction surface 2Ia, but furthermore exerts a torque action which may be adjusted by pulling the ferrule downwardly and twisting it to place the posts 28 in successive bores 29, thereby changing the torque effect of the spring upon the pickup arm generally. As previously stated, in order to relieve the outer wall of the groove from wear resulting from its guiding action upon the needle point, it is desirable that the pickup arm be urged toward the center of the record, particularly in the present instance because of the resistance introduced by the friction surface 2 la. This is readily accomplished by the torque action of the spring 24, and the degree of this action may be varied by a mere downward and twisting movement of the ferrule, as previously described.

While the tendency of the head to twist about the longitudinal axis of the arm I2 in response to vibratory motion of the needle is eliminated to a certain extent by obviating the mechanical joints from within the arm proper, it will be seen that in a mounting of the nature above described no positive means is provided to lock the arm and head against this twisting action. Consequently this lack of positive twist resisting means such as is present in the pivotal joint heretofore used, is overcome by regulating the stance of the inertia element Il' upon its base. By reference to Fig. 3 it will be seen that this element is of considerable width at its lower bearing surface, and therefore the leverage action which permits twisting is eliminated by broadening the base of the inertia member Il.

The lever arm measured by the distance between the horizontal plane of the point at which the needle contacts the record and the parallel plane through the bearing abutment between the element I1 and the friction surface 2id is eterminative as to the necessary width of the bearing surface I9, The greater the above lever arm the greater must be the width. Therefore, as shown in Fig. '7, I contemplate, as an alternative of the construction shown in Fig. 1, a raised platform 32 upon which the friction surface may be mounted. This platform is of such a height that its upper surface is in alignment with the horizontal plane through the point at which lthe needle contacts the surface of the record. Consequently, the above mentioned lever arm is reduced to zero and the necessary width of the element Il to produce the maximum stance is reduced to a minimum. As shown in Fig. '7, in order to bring the above plane into alignment it is found necessary, in the particular embodiment shown, to extend the arm I2 through the body of the inertia member Il and to suitably secure it therein as by screws 33.

The head l of the pickup arm is adapted to receive a conventional mounting construction for the needle Ill, this construction, as is usual, being capable of vibratory action under the influence of the vibrations in the needle, independently of vibratory action in the head and arm. However, as previously stated, in imparting freedom of horizontal arcuate movement to the head in l, -order that the needle may traverse the entire width of the record with ease, it naturally follows that this vibra-tory action of the needle in its mounting is readily transmitted to the arm.

As previously explained, I have provided a pickup arm having an inertia creating mass at its rear end and having a bearing surface at that end, which bearing surface engages a friction surface. The combination of the inertia and the frictional engagement creates impedance to horizontal arcuate movement of the head, and I have found that when the impedance resulting from this combination is greater than the iinpedance of the connection between the needle mounting and the head that virtually no reproi ducing vibrations are transmitted from the needle on its mounting to the pickup arm generally. Consequently, a truer representation of the undulations cut in the record groove are transmitted by means of needle vibrations from that groove to the amplifier than is the case where certain of the vibrations are dissipated and distorted by movement of the pickup head and arm in response to these undulations.

A further important advantage of this impedance at the mounting of the pickup arm is that resonant vibrations resulting from acoustic feed back. mentioned above, or from externally initiated vibrations, do not cause resonant vibrations in the arm to distort the vibrations transmitted by the needle from the undulations on the groove to the amplifier. In Fig. 8 a mpdirled form of the swivel mounting for the pickup arm is shown. This construction utilizes an inverted U-shaped strip 4l secured to the upper cabinet surface suitably secured as by screws 42. An inertia mass 43 having 'the rear end of the arm I2 extending therethrough is positioned within the strip 4l and is suspended upon a cylindrical elastic element 44, the latter being secured to the inertia member 43 by means of a suitable clip 45, and to the top of the strip by a suitable clip 45. The clip 45 is secured to the strip by means of a nut 41 having a lock washer 48 cooperating therewith. In comparing this modiiication with the construction shown in Fig. l it will be seen that it has the previously described inertia resistance to vibration, that it has the resilient mounting to permit freedom of move ment and to protect the construction against abusive treatment, and that by the relative width of the strip, length of the cylindrical elastic element 45, and length and width of the clips 45 and 5S, a form of stance is obtained, by the resistance of the element/i4 to inherent twisting as compared to that twisting action which occurs as the head progresses from the periphery of the record toward the center thereof. Furthermore, with this construction the torque effect of the spring 24 is obtained by loosening the nut 4i and twisting the clip 4t in the desired direction to the desired degree. It will also be seen that the thickness of the member 44 and the resulting stiness afford the same resistance as is obtained by the frictional surface 2 la in Fig. 1.

By reference to Fig. 9 an improved construction adapted to prevent acoustic feed back is shown. The construction is depicted diagrammatically and includes a cabinet 34 having a speaker 35 connected to an amplifier 3|, a motorturntable assembly 35, and a pickup arm 3'! of the character disclosed in Fig. 8, mounted at 35i. As previously described, the phenomenon of acoustic feed back arises from the creation of sound impulses emanating as the result of clicking in the speaker, or as a result of external vibrations, this clicking being caused by the knocking of the needle against the record or some other hard object. When this clicking occurs the impulses travel from the speaker as resonant vibrations and as such tend to react upon the pickup arm assembly so that they are again transmitted through the needle and again emanate from the speaker in amplified form. This recurrence of events occurs until the effect upon the ear is a howl. In order to avoid this disadvantage I have mounted the pickup arm in floating relationship to its base, and furthermore, if desired, the turn- .table assembly together with the pick-up arm mounting and the speaker may be mounted re- .siliently as shown at 39, 4), and 4l respectively. With such a construction it will be seen that the pickup arm assembly is isolated from the remainder of the instrument and thereby does not receive resonant vibrations. In effect a floating reproducing system is mounted with a resonant system. Furthermore, the inertia member, being of a predetermined mass sufficiently great `to resist movement in response tc the lowest resonant vibrations involved, will prevent vibration of the arm in response to resonant vibrations. Thus it will be seen that I have provided a system whereby the vibrations resulting from acoustic feed back will not be transmited to the floating system and will therefore not be retransmitted through the speaker.

It is Well known in the art that lightness in the head of a pickup arm imparts improved reproduction qualities and reduces the degree of wear on the grooves by the needle. However, it is also well known that a pickup arm having a light head will jump from groove to groove without progressing therethrough in the proper manner in the event -that vibrations occur in the floor upon which the instrument is set, It will be seen therefore that while on the one hand lightness in the head is highly desirable, at the same time conditions are encountered where increased weight inthe head is desirable, for instance when the instrument is placed upon a floor which flexes and where dancing occurs. Thus it will be seen that I have added the desired mass to the pickup arm assembly without increasing the weight in the head to any great extent. Furthermore, I have provided means for adjusting the weight of the head in order to accommodate the varying conditions set out above.

In the present embodiment the above means includes a weight 49 fitted into the rear end of the tubular arm i2 in the vicinity of the ino-unting, this weight being shaped or grooved to receive the conduit 30 and being tapped on its upper side to receive a thumb nut 50. The upper side of the rear end of the .arm I2 is slotted as at 5|, the stem of the thumb nut 50 being adapted to extend through this slot. Thus it will be seen that the weight 'i9 may be adjusted longitudinally of the arm I2 by loosening and tightening the thumb nut Ell, thereby to increase or decrease the downward pressure at the head of the arm in accordance with the movement of the weight. If desired, the slot 5| may be graduated as shown at 52 to direct the user in his movement of the weight. Thus if the instrument is placed on a solid foundation or is used in a private home Where vibrations in the floor are of a reduced nature or are not present, the weight may be set toward the extreme rear of the slot 5I. If, however, the instrument is located where considerable activity occurs around the instrument, the weight is moved forwardly the desired amount.

In the construction shown in Fig, 7 it Will be readily understood that because of the location of the screws 33 the inertia member is slotted on the side and the thumb screw extends therethrough and into the side of the weight 49.

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

1. In a pickup assembly, a pickup arm including a needle receiving head portion, an intermediate arm portion, and a rear pivot portion, said head, arm and pivot portion being secured in relatively immovable relationship, a weight associated with said pickup arm at the rear pivot portion thereof, a tension spring secured at its upper end to said pivot portion, a smooth riding bearing surface associated with said pivot portion, means for supporting said pickup arm in the vicinity of said rear pivot portion, said means having an upper friction surface adapted to receive said bearing surface and to resist free movement of said bearing surface thereover, means associated with said supporting means for securing the lower end of said spring thereto, said spring being adapted to exert tension between the pivot portion of the pickup arm and said supporting means to draw the bearing surface of said pickup arm against said friction surface.

2, In a pickup assembly, a pickup arm including a needle carrying portion at one end, a pivot portion at the other end, and an intermediate shaft portion adapted to connect said head and pivot portions, said head, shaft 'and pivot portions being associated in relatively immovable relationship, an inertia member associated With said pickup arm at the pivot portion thereof, a smooth riding bearing surface at the pivot portion of said pickup arm, means for supporting said pickup arm at the pivot portion, a friction surface on said supporting means, resilient means associated with said assembly for connecting said pickup arm with said supporting means and for maintaining said bearing surface and said friction surface in abutting sliding relationship.

3. In a pickup assembly, in combination, a pickup arm including a head portion, an arm portion and a rear mounting portion, said head portion, arm portion and mounting portion being rigidly associated with one another, said mounting portion having a lower surface curved longitudinally of the axis of said arm portion, and a support, said support having a flat surface on its upper side, means associated with said mounting portion for affording a single joint, swivel, non-interlocking connection for operably securing said assembly to the surface of a cabi--y net or the like, said means including a smooth bearing surface on the lower side of said mounty ing portion, said surface engaging the upper surface of the cabinet in sliding relationship, being curved upwardly, rearwardly and forwardly from the point of bearing contact to allow vertical rocking movement of said head portion about'said mounting portion and extending outwardly on each side of the longitudinal axis of said arm portion a distance sumcient to afford a stance for the arm which is great enough to obviate twisting of the latter about its longitudinal axis in response to lateral vibrations imparted to the needle during the playing of a record and means for maintaining said bearing surface and the upper surface of the cabinet in abutting relationship.

4. In a pickup assembly, a rigid pickup arm having a needle bearing head adapted to oscillate over a record carrying turntable, and a remote pivot portion, supporting means for said arm, a pivot connection between said supporting means and the pivot portion of said arm, a tension spring extending vertically to maintain said connection and affording a vertical pivotal axis for said arm, said spring having its upper end non-rotatably secured to said pivot portion of the arm, and a ferrule element associated with said supporting means for rotatable adjustment relative thereto, said spring being non-rotatably secured at its lower end to said ferrule whereby the latter may be adjustably rotated to vary the tensional torque throughout the length of the spring to urge the head in the direction of play toward the center of a record on the turntable.

5. In a pickup assembly, in combination, a rigid pickup arm having a needle receiving head and a remote pivot portion, said head being adapted to oscillate over a record carrying turntable from the periphery to the center thereof, supporting means for said arm, a swivel connection between said pivot portion and said supporting means, yieldable means for maintaining said connection, said yieldable means being secured to said pivot portion and said supporting means under a con- Atal arcuate movement of said head about said mounting portion, in combination, a mass on the arm in the vicinity of the bearing surface thereon, and friction means in the connection between said bearing surfaces for impeding horizontal vibrations of the arm and head in response to lateral, record produced vibrations in the needle, the impedence of said mass and friction means being greater than that between the needle and the head.

7. In a pickup assembly, in combination, a rigid pickup arm having a needle mounting head and a remote pivot portion, a support therefor, a bearing surface on the lower side of the pivot portion of said arm and a bearing surface on the Cil upper side of said support, said surface on said arm being curved away from the other surface in the direction of the longitudinal axis of said arm to enhance vertical, arcuate movement of said head relative to said support and being adapted to ride freely pivotally over said surface on the support to aiford arcuate horizontal movement of the head, and a spring element adapted to maintain said arm and support in cooperative relationship, said element being mounted vertically with its upper end non-rotatably secured to said arm and its lower end non-rotat ably secured to said support and being adapted to serve as the vertical pivotal axis during horizontal movement of said head and arm, to yield longitudinally during vertical movement thereof and to impose torque tension upon the arm and head in the direction of its horizontal playing movement over a record.

WILLIAM H. HUTTER.

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