US3414271A - Device for lifting and lowering a pickup head supported to be variable in height - Google Patents

Description

K. EISEMANN 3,414,271 DEVICE FOR LIFTING AND LOWERING A PICK-UP HEAD SUPPORTED Dec. 3, 1968 TO BE VARIABLE IN HEIGHT Filed June 1, 1967 VLIFTING VLOWERING INVENTOR.

KURT E I S E MAN AGEN United States Patent O 2 Claims. 61. 274- ABSTRACT OF THE DISCLOSURE A mechanism for lifting and lowering the pick-up head on a gramophone record in which a lifting arm for the pick-up arm is supported by an oil-filled damper in the form of a sleeve and a spindle contained therein; the spindle being secured to the lifting arm and the assembly being held together by means of a tension spring. The lower end of the sleeve is coupled to the profiled edge of a lifting cam for the automatic movement of the pick-up. The pick-up arm is also manually controlled by a manually slidable lever having a resilient ramp engaging a projecting part of the lifting arm.

This invention relates to a device for lifting and lowering a pick-up head on a gramophone record located on a turntable, said pick-up head being held by a lifting arm and supported to be variable in height. As is well-known, the pick-up head supported by a lifting arm must be lifted and lowered in gramophones and more particularly in record changers. For this purpose a construction is known, for example, in which the pick-up arm is lifted and lowered by means of a lever which is operated manually. Other apparatus utilize an automatically-operating lifting device controlled by a cam disc for varying the height of the pick-up. However, for many purposes it is desirable that the pick-up can be lifted or lowered at will by means of a lever operated manually, or automatically by means of a cam disc, these two operations being possible independently of each other.

According to the invention, this is achieved in that the vertical spindle of the lifting arm is guided in an oil filled damping sleeve which telescopically surrounds the spindle and which is coupled to the lifting arm through a tension spring, a pin secured in the damping sleeve engaging at one end under the profiled edge of a control disc and being subject at its other end to an upwardly directed tensile force of a second spring, an inclined lifting member in the form of a resilient element, for example a leaf spring having a compressive force which is greater than the tensile force of the first-mentioned spring being arranged in the region of a projecting part of the lifting arm and being secured to an operating rod which is manually displaceable in the longitudinal direction.

A preferred embodiment of the invention consists in that the operating rod is coupled to a slide manually adjustable in the direction of length of the rod, via a hairpinshaped spring which is at an angle with the rod.

In order that the invention may be readily carried into effect, two embodiments thereof will now be described in detail, by way of example, with reference to the accompanying diagrammatic drawing, in which:

FIGURE 1 is a perspective view of a lifting and lowering device according to the invention with control by a cam disc, and

FIGURE 2 is a perspective view, similar to that of FIG- URE 1, of a device according to the invention having a manually adjustable slide.

A pick-up arm 1 shown diagrammatically, which can pivot in known manner, engages via an adjustable pin 2 with the upper surface 3 of a lifting arm 11, rigidly fitted on a spindle 4. This spindle 4 is guided telescopically in a sleeve which is supported at two points, not marked in the figure, and which can also move in the axial direction. At the level of a control disc 7, formed with a profiled edge, the sleeve 5 includes a pin 6 which is at right angles thereto, one end of pin 6 engaging the edge of the control disc 7 and its other end being guided in a vertical slot 8. An amount of oil present in the sleeve 5 serves as a damping cushion during the axial movements of the spindle 4 relative to the sleeve 5. The lifting arm 11 is connected to the lower end of sleeve 5 via a tension spring 10 which ensures that the spindle 4 and the lifting arm 11 are constantly pulled down in the direction b. The function of the spring 10 is to draw the spindle 4 and the lifting arm 11 into the sleeve 5 against the force of the damping, so that the two parts are coupled together under spring force. The force of the spring 10 is approximately 20 grams. On the other hand, the sleeve 5 and the pin 6 are constantly pulled upwards in the direction a by means of a spring 9 connected to the pin 6. One end of the spring 9 is secured to the pin and its other end to the frame (not shown). The function of spring 9 is to pull the total unit 11, 4, 5 in the upward direction when the control disc 7, due to its rotation, no longer hinders the pin 6 so that the sleeve 5 lifts the pick-up arm via 4 and 11 and 2 under the tensile force of the spring 9 (approximately 200 grams).

The lifting arm 11 has a horizontal projection 12 which extends into the region of a leaf spring 13, one end of which is secured to an operating rod 14 which can slide in the longitudinal direction, the free end of the spring extending upwards relative to the rod. The force of the leaf spring 13 must be from three to four times greater than the force of the spring 10 in order that, when the sleeve 5 is forced down via the pin 6 by the rotating control disc 7, the lower side of which is provided with a cam path for lifting and lowering, the lifting arm 11 is held via the projection 12 in the lifted position when, for example, the slide is in the position lifting. The projection 12 is then supported on the spring plate which must be so strong that the lifting arm 11 is maintained in this position against the force of spring 10. The sleeve 5 may thus descend further alone.

At its end remote from the leaf spring, the operating rod in the embodiment of FIGURE 2 carries a supporting pin 15 on which one eyelet of a hairpin-shaped spring 16 engages. The other end of this spring is supported by a pin 18 which is secured to a slide 17.

At the side of the operating rod 14 which can slide in the longitudinal direction, there are provided fixed marks which must indicate with respect to a mark provided on the rod that the rod must he slid up to the one fixed mark or the other, when the pick-up is to be lifted or lowered. Consequently, these fixed marks are preferably provided with the indications lifting and lowering.

When the operating rod 14 of FIGURE 1 has been displaced forwards to such an extent that the mark present thereon finds itself opposite the fixed indication lowering, the projection 12 is clear of the leaf spring and the lifting arm 11, and hence the spindle 4, is pulled downwards by the helical spring 10. It is then assumed that the control disc 7 also occupies a position corresponding to the position lowering of the pick-up.

When it is desired to lift the pick-up, it is necessary to lift the spindle 4 and the lifting arm 11. This may be achieved in two ways.

The pick-up is automatically lifted in a constrained manner upon rotation of the control disc 7, so that the pin 6 the other end of which engages under the control disc having a cam path for lifting and lowering follows this path in a constrained manner under the influence of the spring 9. Consequently the lifting arm 11, and hence the pick-up arm in which the pin 2 is fitted, is lifted via the components and 4. The pin 2 now engages the lifting arm 11.

Independently thereof, the lifting movement of the pickup may be brought about by displacing the operating rod 14 by means of a knob provided on the end thereof, until the mark present on it faces the fixed mark lifting. During the displacement of the operating rod, the raised end of the leaf spring 13 comes under the projecting part 12 of the arm 11. While the sleeve 5 retains its position, the spindle 4 and the lifting arm 11 are then lifted relative to the sleeve 5 by the projection 12, thus bringing the pickup into the lifted position independently of the position of the control disc 7. The pick-up remains in this position as long as the projection 12 is maintained in the lifted position by the leaf spring 13 present below it.

When the pick-up head must be lifted, the control disc 7 would be rotated as a result of which the sleeve 5 would afterwards also be lifted via the pin 6 and maintained in the lifted position by the spring 9. As the pick-up is subsequently lowered, the condition is made that the operating rod 14 shall first be moved back into the position corresponding to the position lowering so that the projection 12 then disengages from the leaf spring 13 and the spring only can still exert influence on the lifting arm.

For satisfactory performance it must be ensured that the leaf spring 13 has a compressive force which is greater than the tensile force of the helical springs 9 and 10 respectively.

The leaf spring 13 may alternatively be a resilient pressure element in that a helical spring is arranged under the free end of a steel band, possibly iron strip, secured at one end to the operating rod 14, said helical spring pushing the free end upwards due to the compressive stress.

A slide 17 which is present in the embodiment of FIG- URE 2, may be displaced between the fixed marks lifting and lowering.

When the slide 17 is pulled towards lifting the hairpinshaped spring 16 is biased as the two points of fastening and 18 of the spring slide past each other. In the final position lifting of the slide 17, the spring 16 exerts a force on the rod 14 in a direction indicated by the brokenline arrow. The leaf spring 13, which is at an angle with the rod 14, then slides under the projecting part 12 of the lifting arm 11, thus lifting it, and hence the pick-up arm, against the force of the spring 10. When the process in the reverse direction is initiated by moving the slide 17 in the direction lowering indicated by the full-line arrow, the rod 14 jumps forwards when the dead center of the hairpin spring 16 is passed. The leaf spring 13 thus slides at the same time from under the projection 12, so that this projection follows by the influence of the tension spring 10, but greatly damped by the oil between the spindle 4 and the sleeve 5, thus slowly lowering the arm 1. The process of lifting and lowering the pick-up arm as controlled by the control mechanism is brought about via the control disc 7, the pin 6 and the spring 9, so that for this process the sleeve 5 is firmly pushed against the lifting arm 11 by the force of the spring 10.

The particular performance of the embodiment shown in FIGURE 2, in which the rod 14 is operated by adjusting the slide 17 via the hairpin spring 16, is based on the fact that direct influencing of the lifting and lowering process is thus prevented.

What is claimed is:

1. Apparatus for lifting and lowering a pick-up head on a gramophone record located on a turntable, comprising means for lifting said head comprising a lifting arm having a vertical spindle and a projecting part, oilfilled damping means comprising a sleeve member surrounding said spindle, first tension spring means coupling said sleeve and said lifting arm, a height control disc having a profiled edge, pin means secured to said sleeve member and engaging the said profiled edge, second tension spring means engaging said pin means and urging the same in the direction of said lifting arm, an inclined lifting member in the form of a resilient element having a compressive force greater than the tension force of said first spring means, said resilient element engaging said projecting part, and an operating rod manually displaceable in the longitudinal direction and securing said resilient element.

2. Apparatus as claimed in claim 1 further comprising manual actuating means for said operating rod, and a hairpin-shaped spring member interconnecting said operating rod and said actuating means.

References Cited UNITED STATES PATENTS 2,192,360 3/1940 Mann 27415 X 2,356,137 8/1944 Weaver 27415 2,723,859 11/1955 Stone 27414 FOREIGN PATENTS 921,855 3/1963 Great Britain. 608,086 9/1960 Italy.

HARRY N. HAROIAN, Primary Examiner.

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