US2014581A - Shock-absorbing mount - Google Patents

Description

sept. 17, 1935.

111/1/11111/111'II/llll/IIILz 'll/Ill L. D. NORTON SHOCK ABSORBINGMOUNT Filed Dec. 6, 1932 11,111 1,111,111,111,filiaal/111,1111,111.

ATTORNEYS Patented 'Sept'. 17, 1,935

UNITED STATES` lPATENT vorrlcle:

v 2,014,581 snoek-ABSORBING MoUN'r Leland D.Norton, Bridgeport, Conn., assigner to Dictaphone Corporation, New York, N. Y.,l a

corporation of New York Application December 6, 1932, Serial No. 645,878

2 Claims.

y from other ofcedevices such as typewriters or f padding machines. This is -especially desirable the caseof reproducing machines used for the transcription of dictation records. Where it has been attempted to mount reproducing-machines directly upon a typewriter desk lit has been found that the shocks and vibrations set up in operating the typewriter have been transmitted to the reproducing machine in such manner as to cause indistinct and distorted reproduction and loud unpleasant noises. This result arises not only by reason of the operation of the keys of the typewriter but also and particularly when the carriage of the typewriter is reversed or thrown back to its right-hand position.`

In reproducing mechines it isnecessary not only that the stylusI mounting has freedom 0f movementvin an up-'and-down direction in order that the stylus may follow a hill-and-dale record and to compensate for variations in the` cylindrical contour of the record, but also that the stylus be mounted for freedom movement in a lateral or horizontal plane in order that the stylus may track the record. Therefore, since the stylus mounting permits freedom of movement of the stylus in both vertical and horizontal planes, the stylus is especially responsive to components 'of shocks or vibrations in those two planes. Vibrations or shocks in the vertical plane Amay cause the stylus to jump up and down, thus 40 skipping or rendering indistinct parts of the record, while lateral shocks such as that caused by the throwing ofthe typewritercarriage from one position to the other may have two evil effects'. One of theseis due to the fact that the needle may be caused to shift from side to side in the record groove and thus not follow effectively the portion of the groove where: the record is most distinct. The other effect results from shocks so severe as to cause the needle to jump from one groove to another, thus causing` repeti tion or omission of a part of the record.

As stated above, these effects are more pronoun'ed with the reproducing machine. However, in the employment of. recording machines where the stylus is mounted for freedom of movement in a vertical plane and ordinarily not 'in a horizontal plane, it is also necessary to mount the machine in such a way as to damp out vibrations and shocks to the highest possible degree and this is particularly necessary in cases where 5 the machines are used upon moving trains or in automobiles.

One of the objects of this invention is to provide a simple and eiiicient mounting ofv the character described. Another object is to provide a 10 shock-absorbing mount for phonographic reproducing machines adapted effectively' to absorb those vibrations which tend most powerfully to interfere with the emcient operation of the machine. 15

Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly cons1sts in the features of construction,A combinations of elements, and arrangements of parts as willbe exemplied 20 in the structure to be hereinafter described and the scope of the application of whichv will be indicated in the following claims.

In the. accompanying drawing in which lis shown one of the variouspossible embodiments 25 of my invention: f

Fig. 1 is a perspective view of my shock-absorbing mount showing in phantom outline a reproducing machine mounted thereon;

Fig. 2 is a cross-section of the shock-absorb- 30 ing mount taken on line 2-2 of Fig.' 1;

Fig. 3 is a cross-section of the mount taken on line 3--3 of Fig. 2; and

Fig. 4 is a cross-section through the sound-box of a well-known type of reproducing machine 35 showing the mounting of the reproducing stylus.

Similar reference characters refer to similar parts throughout the various views of the drawmg.v

In Fig. 1 the ghost outline of the reproducing 40 machineshows it as seated upon a platform Ill which is mounted for free horizontal movement by means of suspension members, indicated generally by the numeral II, which are supported at their upper ends by members I2 formed integral- 45 ly with or attached to a base plate I3. As shown in Fig. 2 pads I4 of felt or the like are attached by means of an adhesive to the underside of the base plate and a cover I5 of billiard cloth or other suitable material is also shown as secured to the 50 underside of the base plate to cover the felt pads I4 andthe otherwise exposed portions of the base. plate. There are four of the brackets I2, each secured to the base plate adjacent a corner thereof and having anupwardly extending -por- 55 Aent invention provides a lmeans for tion I 6 the height of which above the base plate will be determined by the conditions arising from the design of Athe machine which the shock-absorbing mount is intended to support, as will be more fully explained hereinafter.

At the upper end of each upright I6 is a threaded hole I'I adapted to receive a screw I8 which pivotally supports an eyeletmember I9. The suspension member II is composed of two distinct elements, one an inextensible cord or link 20 and the other a stiiily resilient helical spring 2I. The link 20 is made preferably of a length of stranded wire cord which is soldered or otherwise secured at its upper end to the eyelet I9' and which at its lower end is soldered or otherwise secured to an eyelet 22. Eyelet 22 receives and supports an end of helical spring 2|, the'other end of which passes throughan opening 23 in an upturnedY lug or ear formed at one end of a metal strip -36 'secured to the underside of vthe platform IIUy adjacent and parallel to one end of said platform A similar lug at the other end of said strip cooperates with a second suspension member; and a like strip similarlyplaced.

at the other end of said platform is engaged at its two ends by two other suspension members. Thus four-point suspension is provided. -It will be noted that' because of the lateral angularity of the suspension members the platform will have less freedom of movement laterally than longitudinally.

The phonograph shown in Fig. 1 comprises a sound-box 24 supporting a reproducing stylus 25 adapted to track and reproduce the record formed upon a cylinder 26. Referring to Fig. 4 it will be seen that the stylus 25 is carried by a lever 2l pivoted at 28 to a weight lever "29, the stylus lever 21 being connected at its end opposite the stylus 25 by means of a link 30 with the soundbox diaphragm 3l. Thus the stylus is adapted to move up and down about the horizontal pivot 28. The weight lever 29 is also mounted upon a horizontal pivot 32 for movement in an up-and-down direction. The pivot 32 is supported in a member 33 supported in the sound-box by means of a vertical pivot member 34. In the operation of va reproducing machine the weight lever 29 may be .raised or lowered about its pivot 32 in order to permit the stylus to rest upon the record or be lifted therefrom. In its lowered position, as shown in Fig. 4, the stylus will be in contact with the record and will move with the carriage of the reproducing machine from end to end of the record and reproduce the dictation recorded thereon. The freedom of movement of the stylus lever 21 about its pivot 28 permits the stylus to follow the up-and-down irregularities of the record groove while the lateral freedom of movement of the weight' lever 29 about its vertical pivot 34 permits a freedom of movement of the stylus from side to side in order that it may -follow the track of the record.

It will be understood that these parts of the sound-box,

mounting, including the stylus lever and the weight lever, have a. natural period of vibration with respect to the pivot 34 and that the stylus weight 29 has a natural period of vibration about the pivot 32. It has been found that unless these natural periods of vibration are taken into consideration in designing a "shock-'absorbing mount, it is impossible to secure uniformly eilicient results in the use of the mount. The presabsorbing vibrations acting either horizontally or vertically,l

namely, the entire movable stylusL element having elasticity or 4stylus mounting responsive to horizontal' components of shocks or vibrations, namely, the weight pivoting upon the pivot 34, it has been found desirable to give the shock-absorbing mount freedom of movement in a horizontal plane by a suspension means having a natural period of vibration of a lower frequency than the 10. said natural period of vibration of the stylus mounting about its said vertical pivot 34.v This is accomplished by providing that the suspension members I I as a whole from their pivotal attachment points at I8 to their attachment 15 points at 23 be of such length that tha natural period of vibration about the pivots I8 of the platform II) is lower than the natural periodl of vibrationof the stylus mounting about the pivot 34. It will be understood that the link 23 may 20 be a rigid link having universal movement at I8 or, as is preferable, a flexible cord such as has been described above, pivotally mounted at I B for movement in a single plane. Its flexibility permits it to swing in atransverse plane so as to 25 permit movement of the supporting platform I0 either longitudinally or transversely of the base plate I3. It will be further understood that in selecting the length of the suspension members, it is desirable to employ such lengths that not 30 only will the natural period of vibration of the pension members it has been found most practical and *eflective4 to use short, fairly stiil" springs in order that their natural period of vibration will45 be of a higher degree than the natural period of vibration of the stylus weight about its horizontal axis. Such springs will not transmit easily to the stylus vibrationshaving the same frequency as4 the natural period of Avibration of the stylus 50 mounting. Therefore, shocks having vertical components of a periodicity similar to that of the stylus mounting will be absorbed and rendered harmless to produce bad effects upon the stylus action. y 55 As lstated above, while the shock-absorbing mount is herein disclosed in connection with a transcribing machine, it is equally effective when used with a dictation machine, only it should be' understood that the non-resilient and resilient 60 portions of the suspension members should be proportioned with direct reference to the natural periodicity of' vibration of the stylus mounting. Therefore, although the proportions of the parts may be varied, it will be understood thatbest 65 results will be obtained by employing a suspension 'member as herein disclosed comprising a flexible inelastic or non-resilient element whichl is adapted to swing in any direction and a'.l resilient resiliency in the direction of the pull of the support. l

While I have shown the underside of the base plate as being covered with a fabric covering and supported by means of shock-absorbing pads I4,

'these pads are not essential to the satisfactory 75 operation of the device but merely serve to prothe metal of the base plate and facilitate sliding the mount from one place to another upon the desk. Of course the felt pads Il do to some extent act as shock absorbers but this is not their primary purpose. A handle 35 is secured to the base plate, as illustrated in Fig. 1, in order that the shock-absorbing mount with its supported machine may be more readily moved from one position to another.v

It will thus be seenthat this invention provides a construction of an essentially practical nature, in which the several objects of the invention are attained. f

As many possible embodiments may be made oil the above invention without departing from the scope thereof, it is to be lunderstood, that all matter herein set forth or shown in the accompanyi'ng drawing is to be interpreted as illustrative and not in a limiting sense. y

I claim as my invention:

1. In a shock-absorbing mount for dictating machines provided with a sound translation device comprising elements having a natural period of vibration of a certain order in relation to a vertical axis and a natural period of vibration of a different order in relation to a horizontal axis, suspension means comprising a' machine supportf ing platform suspended by a plurality of swingable suspension members, each of said suspension members being of a length to cause its natural period of swinging movement to be of a substantially diEerent order than the said natural period of said translation device elements in relation to their vertical axis, and resilient means iorming a component of each said suspension member and having a natural period of vibration of a substan- 5 tially diierent order than the said natural period of said elements in relation to their horizontal axis, whereby sympathetic vibration of said elements in response to both horizontal and vertical shock components is prevented. 2. In a shock-absorbing mount for dictating machines provided with a sound translation device comprising elements having a natural period of vibration of a certain order in relation to a vertical axis and a natural period of vibration of a different order in relation to a horizontal axis, suspension means comprising a, machine supporting platform suspended y a plurality of swingable suspension members, each of said suspension members being of a length to cause its natural period of swingimg movement to be of a substantially lower order than the said natural period of said translation device elements in relation to their vertical axis, and resilient means forming a component of each said suspension member and having a natural period of vibration of a substantially higher order than the said natural period of said elements in relation to their horizontal axis, whereby sympathetic vibration of said elements in response to bothA horizontal and vertical shock components is prevented.

' LELAND D. NORTON.

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