US2356137A - Pickup arm control mechanism - Google Patents

Description

Aug.22,-1944. J. D. WEAVER 2,356,137

y PICKUP ARM CONTROL MECHANISM v Filed Oct. 17, A1942 INVENTOR 0. WEAVER 4 l" il] .-11

Patented Aug. 22, 1944 PICKUP ARM CONTROL MECHANISM Jerald D. Weaver, Fort Wayne, Ind., assignoi: to Farnsworth Television and Radio Corporation, a corporation of Delaware Application October 17, 1942, Serial No. 462,341

6 Claims.

This invention relates to an improved automatic selective phonograph and more particularly to a mechanism for controlling the pickup arm thereof.

In conventional pickup arm control mechanisms there is provided a cam memberhaving a plurality of cam surfaces for controlling the movement of the pickup arm. A plurality of levers are interposed between the pickup armand the cam member and, when operated by the cam member, they function .to elevate the pickup arm, swing it outwardly and control the movement of the pickup arm for positioning it in engagement 'with the initial groove of a record on the turntable. VThis type of mechanism includes a plurality of'exposed, delicate parts vwhich inherently require a considerable amount of service to' be maintained in a satisfactory operating condition.

An object of the present invention is to provide in an automatic phonograph an improved pickup arm control mechanism which is simple in construction and effective in operation.

Another object of the present invention is to provide an enclosed substantially trouble-free pickup arm control mechanism.

In accordance with the present invention, there is provided an automatic phonograph comprising a turntable for supporting a record thereon, a pickup arm and a pedestal on which the pickup arm is mounted to swing vertically and horizontally into and out of engagement with the record on the turntable. There is also provided Fig. 3 is a fragmentary view, partly in section,

taken on line- 3-3 of Fig. 1 showing the mechanism for retarding the outward movement o f the pickup arm and for swinging the pickup arm inwardly.

Referringparticularly to Fig. 1 of the drawing, the invention here illustrated shows a pickup arm control mechanism which includes a base lplate I0 for supporting a rotatable turntable II on 'which is shown a group of records I2, the uppermost record being in position for reproduction. The turntable II may be driven by any suitable conventional means, for example, such as disclosed in U. S. Patent No. 2,286,490, issued June 16, 1942. A pickup arm I4 is mounted to revolve in a horizontal plane on a pedestal .I5 situated at one side of the turntable II, as shown in Fig. 1. Atfthe free end of the pickup arm I4. there is provided apickup I1 with a stylus I8 which is adapted to cooperate with a record on the turntable I I to reproduce it in the conventional mannel'.

bearing member 2| provided on a plate 22. The plate 22 is pivotally mounted on a pin l23 which isxed to a plate 24. The plate 24 is connected tothe upper end of a rotatable hollow shaft 2B in-which a pin 21 is adapted to move'vertically.

When the pickup arm I4 reaches the end of a record, the pin 21 (Fig. 1) is moved vertically into engagement. with the plate `22 and-moves the a driving mechanism for carrying out a recordchanging cycle and a novel control device comprising a hydraulic mechanism connected to the driving mechanism and the pickup arm for elevating the pickup arm, swinging it outwardly beyond the periphery of the the pickup arm to the initial playing groove of the record on the turntable during a recordchanging cycle.

For a better understanding of the invention,

record -and returning together with other and further objects thereof, reference is had to the following description, taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the accompanying drawing:

Fig. 1 is a side-elevation, partly in section, of the pickup arm support and control mechanism in accordance with the invention.

Fig. 2 is a fragmentary view, partly in section,

plate .22 in a clockwise direction bearing pin 23 thereby to move a screw 30 on the plate 22 in engagement with the underside of the pickup arm I4 to elevate the stylus I3 out of engagement with'- the record being played. Immediately after the pickup arm I4 is elevated, the

(Fig. 1) on the shaft 26 is rotated to swing the pickup arm I4 horizontally outwardlyY to non-playing position. 'I'he mechanism for and for rotating the shaft 26 will be described hereafter.

vand. 21 is shown in Fig. 1 and comprises-a hytaken on lineZ-Z of Fig. 1 showing the interior of the cylinder and the member therein for moving the pickup arm horizontally outwardly.

draulic mechanism including a housing 32 providing a cylinder 33 in whih a piston 34 fixed to the lower end of the pin 21 is adapted to be moved vertically to elevate the pin 21 and pickup arm I4. To the upper end of the cylinder 33 there is ailixed a sleeve member 35 for supportingl a bearing assembly 36 which rotatably supports the shaft 21. concentric with the upper As shown in Fig. l, the pickup arm I4 may be pivotally mounted on a pin 20 supportedby a moving the pin 21 vertically moving the elements 2 cylinder 38. A baille 39 shown in Fig. 2,y is formed on the inner wall of the cylinder 38 to extend to the outer wall of the cylinder 33, and

from the bottom of cylinder 38 to the cap member 40. A rotatable member 42 is fixed to the lower end of the shaft 28 and, as shown in Fig. 2, the member 42 has two vanes 43 and 44. The vane 44 is adapted to engage a stop 45 whenthe member 42 has been rotated a. predetermined dis'- tance in a counterclockwise direction. When the member 42 is rotated, the shaft 26 and the pickup arm I4 are likewise rotated in a horizontal plane. Adjacent to the lower end of the cylinder 33, there is provided a third cylinder Alili (Fig. 1). The cylinder 41 is connected to the cylinders' 33 and V38 by ports 43 and 43, respectively. The cylinder 41 and lower portion of the cylinder 33 are lled with a suitable fluid such as oil.

A piston I, aiilxed to a connecting rod 52, is provided to reciprocate in the cylinder 41. When the piston 5I is moved totheiright (Fig. 1), in a manner to be described hereafter, iiuid from the cylinder 41 is forced through the openings '48 and 49 into the cylinders 33 and 38.

As shown in Fig. 1, a spring valve member 53 with a small port 54 is provided in the lower end of the cylinder 33 and is adapted in one position partly to close the opening QS. When the uid is forced through the opening 59 from the cylinder 41 to the cylinder 33, the member 53 is moved away from the opening 49 to permit fluid to enter the cylinder 33 .with less obstruction than provided to the cylinder 38 having the smaller opening 48. When the stylus of the pickup arm I4 is over the initial playing groove of a record, the vanes 43 and 44 are in the full line position (Fig. 2) and when the pickup arm has moved into the trip groove of a record, the vanes 43 and 44 are in the dotted line position shown in Fig. 2. When uid is forced into the cylinder 38 in the area between the bae 39 and the vane 43, the member 42 is rotated in a counterclockwise direction (Fig. 2) thereby to rotate the shaft 26 and the pickup arm I4 outwardly with respect to the turntable. The rotation of the shaft 26 is retarded by a spring member 55 (Figs. 1 and 3), one end ofwhich is anchored to the shaft 26 and the other end of which is movable in a slot 56 provided in the cap member 40 (Fig. 3).

Since the fiuid is permitted to flow faster into the cylinder 33 than into the cylinder 33, it will be evident that the piston 34 and the pickup arm I4 will be elevated before a sumcient amount of uid is forced into the cylinder 38 to rotate the member 42. When the piston 34 'is elevated sufciently far to engage the lower end of the sleeve member 35 (Fig. 1) the pickup arm is elevated out of engagement with the record on the turntable. Thereafter, the piston 5I ceases to force iiuid into the cylinder 33` and` the spring valve member 53 moves back to partly close the opening 49, as -shown in Fig. 1. As the piston 5I continues to move to the right, the iluid forced into the cylinder 38 rotates the member 42 in a, counterclockwise direction (Fig. 2) thereby swinging the pickup arm outwardly.v When the pickup arm I4 has been swung outwardly to a position approximately over the outer groove of a record on the turntable, the free end of the spring member 55 engages the lower end of the slot 56 (Fig.

.3). Further rotary movement of the member 42 builds up tension in the spring member 55. When 44 is moved into-engagement with the stop 45 (Fig. 5) and the pickup arm is moved beyond the edge of the record on the turntable.

When the piston 5! is moved to the left (Fig. l) the fluid is gradually drawn from the cylinders 33 and 38. Thereupon, the spring member 56 rotates the member 42 in a clockwise direction (Fig. 2) to swing the pickup arm inwardly and the Weight of the pickup arm on the pin 21 forces the piston 34 downwardly. This horizontal and vertical movement of the pickup arm is controlled by the movement of the piston 5I as it draws the uid from the cylinder 38 through the large opening'48 and from the cylinder 33 through the small opening 54 in the member 53 (Fig. 1). From the above, it will be apparent that the fluid will be expelled from the cylinder 38 faster than it is expelled from the cylinder 33. Thus, it will Abe evident that the pickup arm I4 will be moved inwardly under the biasing action of the spring 55 Yto a position immediately over the initial groove of a record on the turntable before the weight of the pickup arm I4 on the pin 21 forces the piston 34 downwardly to the position shown in Fig. 1 where the stylus it of the pickup arm I4 engages the record on the turntable.

Driving `mecmnism for hydraulic control I0. The shaft 53 may be driven by any suitable Amotor and gear mechanism known in the art.

U. S. Patent No. 2,018,881, issued October 29, 1935, 'discloses one form'of this mechanism. The shaft f 53 has affixed thereto a cam wheel Gil adapted to rotateitherewith which is provided with two angular citmruri'aces` @I and 82 and a concentric cam surface 63;

A spring-biased lever S5 is plvotally connected as at 66, to the bracket 59 (Fig. l). The upper end of the lever 65 has a rectangularaperture G1 which engages al pin 68 fixed to the connecting rod 52. of the lever 65 is biased into engagement with the cam wheel 60 by a tension spring 1i which has one end anchored to the pin 'i2 iixed to the bracket 59 and the other end engaging the edge of the lever 35, as shown in Fig. 1.

In operation, after the record on the turntable ii is reproduced and the stylus I3 moves intov the trip groove, a tripping mechanism, such as disclosed in U. S. Patent No. 2,018,881, issued October 29, 1935, may be incorporated in this apparatus to initiate the rotation of the shaft 58 through a cycle of operation'. When cam wheel 6B begins to rotate, the cam surface engages the roller 1I! to move the lever 65 in a clockwise direction (Fig. 1) against the biasing action of the spring 1I. As the lever 65 moves. the left-hand edge of the aperture 61 engages the pin 68 and moves the rod 52 and the piston 5I to thev right against the biasing action o1' a spring 69 (Fig. l). The energy stored in the spring 69 is of such propor- A' tion that only a force slightly greater will be rethe piston 5I has completed its stroke, the vane 75 quired to overcome the frictional engagement between the piston 5I and the cylinder 41.

The piston 5I, in moving to the right (Fig. l) forces fluid into the cylinders 33 and 33 to elevate the pickup arm and swing it horizontally beyond the edge oi the record on the turntable in the manner heretofore described. .While the roller 10 is in engagement with the cam surface 63. the

A Aroller 10 flxed to the lower end piston I is maintained near the right-hand line position (Fig. 2).

end of the cylinder 41 and the pressure inthe cylinders 33 and 38 holds the pickup arm elevated above andbeyond the record lon the turntable. When the cam surfacel 62 engages the rollerlll, the spring 'Il moves the lever 65 in a clockwise direction (Fig. 1) to move the right-hand edge of the aperture 61 into engagementl with the .pin 68 and thereby moves the rod 52 and the piston 5| to the left (Fig. 1).` 'Ihe piston 5l, in moving, permits the tension spring 55 to rotate the mmber 42 in a clockwise direction to swing the pickup arm inwardly over the :outer groove of the record on 'the turntable and thereafter` the piston 34 gradually lowers the stylus I8 into engagement with the record on the turntable Il. By the time the cam 4wheel completes a cycle` of operation, the lever 65 is moved back to the position shown in Fig. 1. However, due to' the length of the aperture 61, it is evident that the lever.. 65

moves in a counter-clockwise direction a predetermined distance before it functions to move the rod 52 and .the piston 5l to the left relative to the cylinder 41. Therefore, when thelever reaches its normal position shown in Fig. 1, it is 2. In an automatic phonograph comprisingva rotatable turntable for supporting a record, a reproducing means including a pickup arm, a hydraulic mechanism including a'. first cylinder, a

rotatable member adapted to rotate therein and having a shaft portion on which said pickup armis pivotally mounted to move vertically and horizontally into and out of engagement with a record on said turntable, a second cylinder, a

piston movable in said second cylinder .to elevate said pickup arm, a-third cylinder connected to said first and second cylinders by. openings and filled with a fluid and a piston movable in one direction in said third cylinder 4to force said fluid into said first and second cylinders for elevating said pickup arm and rotating said member to swing said pickup arm beyond the recordon said turntable and movable in the opposite direction evident that the piston 5l is not returned to the normal position, and the pickup arm I4 ceases to be moved inwardly by the movement of the piston 5| and the tension of the spring 55. With the piston out of its normal position, it is evident that a portion of the iiuid remains in the cylinder In order for the mechanism to function properly during the succeeding cycle of operation, it is necessary to move the piston 5l back to the position shown in Fig. 1. To do this, only a force slightly greater than that of the spring 69 needs to be supplied. This added force is developed by the movement of the pickup arm as it reproduces a record. As the pickup arm moves inwardly, the vane 43 is moved from the full line to the .dotted This movement of the vane 43 forces the fluid remaining in the cylinder 38 into the cylinder 41. This force cooperates with the spring 69 to move the piston 5| back to the position shown in Fig. 1.

While there has been described what is at pressaid fluid through said openings into said first.

for returning the pickup arm into engagement with the beginning of the record on said. turntable, and operating means connected to said piston in said third cylinder.

3. In an automatic phonograph comprising a rotatable turntable for supporting a record, a reproducing means including a pickup arm, a

pedestal, a rotatable tubular shaft associated with said pedestal and pivotally supporting said pickup arm to move vertically and horizontally thereon into andv out of playing engagement with a record on said turntable, a bearing member for rotatably supporting said rotatable shaft, a pin movable vertically in said shaft for elevating said pickup arm, a hydraulic' mechanism including a first cylinder, a piston connected to said pinand movable in said first cylinder for elevating said pin and said pickup arm, a second cylinder, a

f member fixed to said rotatable shaft and rotatable in said second cylinder, a third cylinder connected l to said first and second cylinders by openings and filled with a fluid and a pistonmovable in one direction in said third cylinder for forcing and second cylinders for elevating said pickup arm and rotating said shaft to swing said pickup arm horizontally beyond the edge of said record on said turntable and adapted when moved in the opposite direction to draw said fluid-from said ent considered the preferred embodiment of the tatable member on which said pickup arm is mounted to move vertically and horizontally into and out of play engagement with a record on said turntable. an elevating member movable vertically in said rotatable member and adapted to elevate said pickup arm out of engagement with said record on ,said turntable, reciprocable hydraulic means for operating said elevating member for elevating said pickup arm, rotatable hydraulic meansfor operating said rotatable member and swinging said pickup arm horizontally beyond the record on said turntable and returning said pickup arm into engagement with the initial groove of said record on said turntable, and operating means for controlling said hydraulic means.

first and second cylinders and control the inward movement of said pickup arm and the return movement of said piston in said second cylinder to properly position said pickuparm in engage- .ment with the beginning of said record on said turntable, and operating means connected to said piston in said third cylinder.

4. In an automatic phonograph comprising a rotatable turntable for supporting a record, a

. reproducing means including a pickup arm, a

pedestal, a rotatable tubular shaft associated with said pedestal and pivotally supporting said pickup arm to move vertically and horizontally thereon into and out of playing engagement with a Vrecord on said turntable, a bearing member for rotatably supporting said rotatable shaft, a pin movable vertically= in said shaft for elevating said pickup arm, a. hydraulic mechanism including a first cylinder, a piston connected to said pin and movable in said first .cylinder for. elevating said pin and said pickup arm, a second cylinder, a member fixed to said rotatable shaft and rotatable in said second cylinder, a third cylinder 'connected to said first and second 'cylinders by openings and illledwith a fluid and a piston movable in said third cylinder for forcing said fluid into said first and second cylinders when moved in one direction for elevating said pickup arm and rotating said shaft to swing said pickup arm horizontally beyond the edge of Vsaid record on said turntable and when moved in the opposite' direction for drawing said fluid from rst and second cyinders thereby controlling the inward move- A ment of said pickup arm and the return movement of said piston in said second cylinder to properly position said pickup arm in engagement up arm lhorizontally beyond vthe edge 'of said record on said turntable and for controlling the inward movement of said pickup arm toa point immediately over the beginning of a record on said turntable, a valve member in said second cylinder for controlling the lowering of said plston in said second cylinder to properly position said pickup arm in engagement with the beginning of said record on said turntable, a spring vertically in said shaft for elevating said pickupl arm, a hydraulic mechanism including a rst cylinder, a piston connected to said pin and movable vertically in said first cylinder for elevating said pin and said pickup arm, a second cylinder, a member xed to said rotatable shaft and rotatable in said second cylinder, a third cylinder connected to said rst and second cylinders by openings and filled with a fluid, a piston movable in said third cylinder for forcing said uid into said ilrstand second cylinders for elevating said pickup arm and rotating said shaft to swing said pickmember connected to said shaft and said hydraulic means for swinging said pickup arm inwardly toward the center of the record on said turntable, and operating means connected to said piston in said third cylinder.

6. In an automatic phonograph comprising a rotatable turntable for supporting a record, a reproducing means including a pickup arm, means vfor supporting said. pickup arm whereby it may move vertically'and horizontally into land out of playing engagement with a record on said turntable, a reciprocable uid operated means connected to said pickup arm for elevating it, a rotatable fluid operated means connected to .said pickup arm for swinging it horizontally beyond the edge of the record on said turntable and returning said pickup arminto engagement with the initial groove of the record on said turntable during a record changing cycle, hydraulic control means for operating both said fluid operated means, and operating means for actuating said hydraulic control means.

JERALD D. WEAVER.

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