US2214509A

US2214509A - Pick-up support

Info

Publication number: US2214509A
Application number: US197107A
Authority: US
Inventors: Otto Ewald
Original assignee: Telefunken AG
Current assignee: Telefunken AG
Priority date: 1937-03-25
Filing date: 1938-03-21
Publication date: 1940-09-10
Anticipated expiration: 1957-09-10

Description

Sept.10, 1940. T 2,214,509

PICK-UP SUPPORT Filed March 21, 1958 Fig.1

In ventan' Fwzz dd O-io Patented Sept. 10, 1940 UNITED STATES .PATENT OFFICE signor to Telelunken Gesellsc lose Telegraphic m. b. 11.,

halt fiir Draht- Berlin, Germany, a

, corporation of Germany Application 3 Claims.

The present invention relates to a device for the protection of the stylus or needle of mechanical or electrical devices for the reproduction of sounds from sound records, herein gen- 5 srally referred to as sound pick-ups.

With careless treatment of sound pick-ups, ior example, in dropping or heavily placing them on the pick-up stylus, the pick-ups are often damaged, especially the armature and its hearing in the case of electrical pick-ups. If semiprecious stones are used, as it has recently be-. come customary, for picking up the recorded sounds, the danger exists that the stylus will break, or at least that the tracing point of the broken out of its setting. If the sound pick-up, with the stylus, falls onto the sound disc, this latter also will be damaged by the breaking of parts of the mass of the disc.

It is already known for the protection of the sound pick-up or the disc to arrange on the sound pick-up a supporting lever, which is moved into such a position by a spring that when the pick-up is allowed to fall, it falls on this support. .The length of the support is so dimensioned that in this case the point of the needle or of the pick-up stylus does not come into contact with the underlying surface, for

example, the sound disc. By this means, any

danger to the pick-up or disc is avoided. When so now the pick-up is placed on the disc, the supporting lever is pushed away as a result of frictionally engaging with the rotating sound disc and thus the needle engages and follows the sound groove.

This embodiment suflers from the disadvantage that in consequence of the construction of the support as a lever, moving of the lever and thereby the lowering of the needle point onto the disc is brought about rather quickly, and, moreover, the end of the lever acting upon the underlying surface is pushed aside if the pick-up is allowed to fall from a somewhat great height, so that only a small diminution of the blow is effected. Moreover, in such a case the pick-up can, consequent upon the spring action of the support or of the disc, spring away from the record and fall on the point of the stylus when it falls downwards again.

The invention relates to a similarly operating 50 device for the protection of the stylus of sound pick-ups from destructive action on falling or on being heavily placed upon the sound disc or other underlying surface without the disadvantages of the known arrangements, and

semi-precious stone will break off or the stone.

March 21, 1938, Serial No. 197,107 Germany March 25, 1937 consists substantially in that a support, projecting from the casing of the sound pick-up like the stylus, is constructed as a flattened disc or roller, or as a disc or roller pivoted eccentrically, which is held in a position by gravity 6 or by a spring, in which position damage to the sound pick-up or the disc is prevented if the pick-up falls on the disc. The roller or disc comes into contact with the underlying surface or sound disc before the stylus. .The support is 10 tilted by the rotation'of the sound disc until the stylus engages with the sound disc. The rolleror disc-shaped construction of the support is distinguished from the lever-shaped constructions of such supports in that the stylus glides I quite slowly into the sound groove. Moreover,

on account of the extremely small moment of inertia of the roller, the power necessary to move it back is very small so that the sliding friction of the'roller on the sound disc is reduced. Since, moreover, the roller-shaped construction makes it possible to keep the operating lever arm very short, the danger of the lever being moved to one side does not arise when the sound pick-up springs up again from the underlying surface after falling upon it. On the contrargr, it is always assured that the pick-up falls on he support.

Thus, on a sudden placing or on a, dropping of the pick-up, only the support comes into contact with the underlying surface in the firstinstance, whilst the stylus is still positioned at a certain distance therefrom and for this reason cannot become damaged, nor can heavy impulses be transmitted to the magnetic system. The support can be constructed without any dimculties in'such a manner that it can, easily absorb hard mechanical blows and thus is scarcely subjected to wearing out or damage, particularly since the weight of the sound pick-up is small. 40 This small weight, however, isconsiderable when compared with the fine construction of the pickup stylus and of the magnetic system.-

For a fuller understanding of the nature and ojbects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:

Fig. 1 shows a side elevation of the tone arm and the pick-up with the protection device;

Fig. 2 shows a side elevation of the pick-up in a greater scale;

Fig. 3 shows a modification of the device.

In Fig. 1, the tone arm I carries at its foreprotection most end the sound pick-up 2, the stylus l of which is placeable on a sound disc 4 in the usual manner. For the protection against heavy blows on the stylus 3 in placing the sound pick-up 2 on the sound disc 4, a disc 5 is provided which is pivoted at its centre 6 and is partly flattened at I. By means of the spiral spring 8 fastened thereto the disc 5 is so positioned when the pickup is lifted up that the circular shaped part projects below the lower edge 9 of the pick-up and, indeed, more than the stylus 3, which for this reason cannot then engage with the groove of the sound disc on placing the pick-up on the sound disc 4. On account of the movement of the sound disc 4 the support consisting of the disc 5 is turned in the direction of the arrow to the end of the circular shaped part wihch merges gradually into the flattened portion 1, as shown in Fig. 2. Thus the distance between the periphery oi the support and the axis of its pivot decreases in the direction of the flattened portion. Since this part projects below the bottom of the pick-up 2 less than the stylus 3, the stylus '3 is placed slowly upon the sound disc on gradual transition of the circular shaped part of the disc 5 into the straight part. By means of the rotary movement of the underlying surface or sound disc, a return of the disc 5 into the initial position shown in Fig. l, is prevented during such time as the pick-up lies upon the sound disc. Thereby, the disc 5 always slides with its straightened part directed downwardly on the sound disc, without any scratching noises however arising.

Another embodiment according to the inven-- tion is shown in Fig. 3. In this case, a circular disc ll serves as a support and is excentrically pivoted on the sound pick-up at [2. By means of an additional weight I3, preferably of lead, the centre of gravity of the disc I I is brought as near as possible to its circumference so that the disc ll hangs downwards when the pick-up is lifted and thereby projects below the lower limiting surface 9 of the pick-up by an amount greater than the pick-up sytlus 3. Consequently, in placing the pick-up 2 on to the sound disc 4, the part ll of the disc ll first comes into contact with the sound disc; but, consequent upon the rotation of the disc on the pick-up, it is moved gradually aside by the moving underlying surface while the depth of the part of the disc projection below the surface 9 is reduced until finally the stylus 3 engages with the sound disc. The lead weight 13 is advantageously placed in a cut-out portion of the disc which consists, for example, of light metal.

In both the embodiments shown by way of example, the supports are returned into their initial position after the raising of the pick-up from the underlying surface or sound disc, either by the spring (Fig. 1) or by gravity (Fig. 3), in order to come into operation before the stylus when the pick-up is again put into position. The effect of the spring or the weight of the disc for this reason act in opposition to the rotating force exerted at the circumference of the disc by the] sound disc.

The most eflicient working of the protecting device is ensured if the pivot of the support is at right angles 'to or across the direction of movement of the sound disc or other underlying surface.

While specific embodiments of the invention have been disclosed it will be understood that changes may be made therein without departing from the main features of the invention as set forth in the appended claims.

I claim:

1. The combination, with a pickup device including a stylus adapted for engagement with a disc record, of a support attached to said device by means of a pivot, said support having a curved surface including a section adapted for rolling engagement with a rotating record when the device is lowered, said section having a contour characterized by a decreasing distance between the periphery thereof and the axis of the pivot from one end of the section to the other, the portion of said section most remote ,from the axis of the pivot initially contacting said record, and

means normally maintaining said support in such position on its pivot that the end of said section which has the greatest radius engages the record when the device is lowered, whereby the rolling action which is initiated by the engagement of the support with the record, continuously lowers the device from the beginning of the turning movement of the support until the stylus engages the record, said section having suflicient length to insure that the stylus is brought into engagement with the record without shock. Y

2. The combination as set forth in claim 1, characterized by the provision'of the support in the form of a disc having a flattened section, into which the said curved section merges.

' 3. The combination as set forth in claim 1, characterized in that said support is constructed in the form of an eccentrically pivoted disc, and a weight for maintaining the disc in its normal position.

EWALD O'I'IO.