US 2043769 A
Description (OCR text may contain errors)
June 9, 1936. L. D. NORTON RECORD TABLET Filed Feb. 12, 1952 INVENTOR M4/.9. Wm
' BY zwwby @Zw l M ATTORNEYS Patented June `9, 1936 UNITED STAT Es PATENT omer 2,043,769] `j I ARECORD TABLET Leland n. Norton, Briagepoaconn., assignorfto Dictaphone Corporation, New York, `N. Y.,` a corporation `of New York 1 j I Application February 12, lssaseriamo. 592,548
.- This invention relates" to sound record tablets and with regard to certain more specific features to reinforced sound recordtablets.
`One of the objects of the invention `is to provide 1'5"? an inexpensive,reinforcingmediumfor a sound4 record` tablet, said. medium being `substantially and arrangements ofiparts which willbe exemplifiedin the structure to be hereinafter described and the scope of theapplication of which willbe indicated in the following claims.
In lthe accompanying drawing, in which` is shown one of the various possible embodiments of the invention, i Figure 1 is avertical axialsection of a cylindrical sound record ,tablet which embodies the invention; Y I I f Figure 2 `is a vertical axial section of a mold used in makingthesoundrecord tablet of Figure 1, and shows a reinforcement embodying the invention positioned on the c ore of the mold;
, `Figure 3 is `a fragmentary detail plan viewfof the, reinforcing medium of Figure 2; and,
Figure 4 is a verticahsection `taken` on line 4-,-4ofFigure3., Corresponding reference characters indicate corresponding partsthroughout the several views of the drawing..` Referring now more.. particularly to Figure 1, there is shownatnumeral I a sound recordtablet in the form of a hollowv cylinder, upon the outer surface 3 of `which a. soundrecord is adapted to be recordedsby a suitablerecording stylus, the sound record thusmade ,being-capable of later `rc'aproduction by a suitable reproducing stylus.
During` thewabove operations the soundrecord tablet `is usually supported upona mandrel havingresilient means, comprising.` friction devices, for rmlyengaging the inner surface of the sound record tablet, `and .holding it against" rotational movement or longitudinal movementrelative to the mandrel. The mandrel upon whichthe record tablet is'placed is taperedfan'd consequently the, internal 5 "of the record is also tapered.
Numeralsl and 9 indlcatethe `larger and ,top of the shell 23.
smaller `ends ofthe taper respectively, The taper is provided among other reasons, to` enable the tablet to be easily withdrawn frornthecore when f being made and to allow the tablet to be easily applied to and removed lfrom the mandrel. Inv 5 order to improve Vthe grip of the mandrel `upon 4the tablet, the inside surface 5 is fluted withhellcal ribs IIland grooves II.
The cylinderg Iiduring the recording and reproducing,operations,jand even whennot` positioned 10 I `on. almandrel is subject to various stresses and strains caused by temperature-changes and by the friction `devices on' the mandrel. Stresses and strains mayresult also from droppingthe record or from hitting. itagainst a. solidobject.` For 15 these andlother, reasons ithas been customary to embody in the -.Waxlike materialx I3 from which therecordtablets I I` aremade, a reinforcing me,- dium I5, which tends to prevent thestresses and strainsfrom cracking the cylinder. VIt is `advan-` 20 tageous to have a. reinforcing medium I5 towhich the wax-like material Iateffectively` adheres because,.ln the event of4 a blow which is great enoughtto shatter or crack the record, notwithstanding the. reinforcing liningIS, the reinforc- 25 I ing `mediumshould be able to holdthe piecesof shattered waxlikematerialin close contact with each other inthe position which they' were prior to theshattering or cracking. Rubber reinforc-` ing linings I5 have been used for this purpose 30 and are.effective in` holding the pieces lof the shattered record together, becausethe congealed wax-like material tends to adhere to therrubbe'r lining.` However, in some instances .the rubber lining is not `entirely satisfactory, because the 35 heat of the molten wax-like material softens the lining, which is then "ableto moveinto the hollows of the helix I2 of the core land` so is positioned inthe ribs I0 of the molded record cylinder. The presence 'of rubber lining in the ribs I0 may inter- 40 ferev later with the rearningofA the cylinder, by gumming up the reamer. s
AA record cylinder such as isshown in Figure 1 may be produced in manufacture from a mold I1, as shown in Figure 2; The ribs IllA andgrooves 45 II are produced bypa c ore I 9 having` a helical `surface which core is mounted n a base 2l lof the mold I1, the base `also holding a shell` 23 concentrically of the core I9, In the `manufacture of the record, themolten wax-like material I3 is 50 poured into the shell through the openingfat the After the wai-ry material I3 cooled'off suicientlyto congeal, `the shell-23 l is removed `from the record tablet by any suitable means, and the core I8 is removed-by screwing it 55 outof vthe record. Thus in this way the ribs I and grooves II act as a thread to facilitate the withdrawal of the core from the record.
Prior to the pouring of the wax-like material AI3 into the shell 23 the reinforcing medium I5 is positioned over the core I9. The reinforcing medium essentially comprises a tapered tubular lining, and is made to just ,touch the crests I 2 of the helix formed upon the core. It is decidedly advantageous that the helix be preserved in the finished cylinder, and hence it is desirable that the lining I be sufficiently porous or openmeshed to allow the molten material I3 to iiow through from the outside of the lining as it is poured into the shell 23 to the surface of the core I9, whereby the lining I5 is substantially entirely' embedded within the waxy cylinder thus formed.
As above pointed out, it is desirable that the wax-like material I3 and the reinforcing lining I5 adhere to each other; and it is further desirable that the lining I5 be slightly elastic, or if it be inelastic, that the bond between the lin-- ing I5 and thewax-like material I3 be slightly elastic, in gorder that the differences in the expa'nsions of the wax-like material I3 and the lining I5 due to changes in temperature may beA compensated. It has been customary to use a relatively non-elastic material such as crinoline as a reinforcing medium I5. Thecrinoline is not affected by the heat of the molten wax-'like material I3 and so does not move into the grooves of the core helix when the material' I3 is in a molten condition. However, the use of crinoline alone is vnot entirely satisfactory because the wax-like material does not adhere to the crinoline after congealing'and in the event of shatteringof the record thev individualpieces of the wax-like material may fall away from the reinforcing medium I5. Further, the helices formed on the ,interior of a. record cylinder, because of the intervening layer of reinforcing material, are not very securely united with the waxy material yforming the body of the cylinder, so that unless there is effective adhesion between the waxand the lining, the threads of the helix are apt to bebrok'en or chipped olf by contact with the ends of the mandrels upon which the cylinder is'used, Q As a'result the cylinder is unevenly supported when seated upon a mandrel for use in recording or reproducing. Thus the cylinder is subjected to uneven stresses and strains, and is likely to become cracked or the recording or reproduction to be distorted. Furthermore, the crinoline,'being substantially inelastic, may of itself cause cracking of the wax material I3 when the cylinder is subjected to temperature changes, because ofthe different coefiicients of expansion of the wax-like material and the crinoline.
In the present invention I have provided an improved reinforcing lining I5 which overcomes all of the above-mentioned difficulties. My lining comprises the usual open-meshed fabric 25, such as crinoline, or the like; but I treat the fabric 25 with a binder 21 (see Figures 3 and 4) which accomplishes the desired results. I have found that a binder 21 which adheres to the crinoline 25, and also to the wax-like material, and which of itself possesses `some Aelasticity is satisfactory. The' binder 21, which I propose to use also should be of such a nature that it may be applied to the crinoline 25 without filling up the interstices of the crinoline; otherwise, the molten wax-like material I3 could not. flow through the lining I5 to the surface of the core I9 as above described.
I have found that a material such as, for example, latex rubber (coagulated latex) fulfills the requirements of a satisfactory binder 21; and that a crinoline lining 25, coated with latex rubber, sticks to or adheres to the congealed waxlike material I3 and vice versa. Further, the latex rubber' is sufficiently pliable and elastic to compensate for the differences in the expansions of the two materials (the crinoline and the material I3) with temperature changes.
The manufacture of a cylindrical sound record employing my invention may be carried out as follows:
A sheet of the open-meshed fabric 25 is rst treated with a solution of latex rubber or the like, before it is formed into a tube. Care is taken to use a thin solution, to prevent the latex rubber from filling in the interstices of the openmeshed fabric. The solvent of the solution is then evaporated, and the individual threads of the crinoline are left coated with a lm of latex rubber. The crinoline sheet is now cut to the proper sizes and permanently formed into tubes byv juxtaposing'edges of the sheets, and pressing them together. The edges are held in this position by the adhesive properties of the binding agent 21. In this way the reinforcing tubes or linings I5 are formed without additional fastening means such as thread, rivets, or the like.
A crinoline tube I5 with theindividual threads coated with rubber latex is now positioned on the core I9 and the molten waxy material I3 poured into the Shen 23. The wax nows through the interstices of the lining I5 which have not been closed by the latex rubber 21. As hereinbefore pointed-out, the crinoline 25 is not affected by the heat of the molten wax I3 and does not stretch into the hollows of the corehelix, but retains its shape throughout the pouring of the wax I3. The molten wax coming into contact with the binding agent 21 on the individual threads of the crinoline adheres to the agent 21 after congealing. In the event of shattering of the record the shattered pieces of waxare held in close contact with each other because of the lining I5 and the binding material 21.
Although I am not aware of the exact physical and/or chemical action which takes place between the molten and/or congealed wax-like material I3 and the latex rubber 21, I am aware that the congealed wax-like material does adhere firmly to the latex rubber. Other binding agents may be used to accomplish this binding between the crinoline 25'and the wax-like material I3, and accordingly I do not wish to limit my invention to the use of latex rubber.
A record manufactured in accordance with my invention will not fall to pieces when subjected to a shattering, butv will maintain its original shape, the pieces of the wax-like material being held together firmly by the crinoline, so that reproduction of the record is possible even though the cylinder be broken. Moreover, pieces of wax-like material which are chipped from the interior of the cylinder by the ordinary wear and tear of putting a cylinder on and taking lt off a mandrel, are retained in position by the adhesive and elastic action of the binder 21.
As various embodiments might be made of this invention, and as various changes might be made in the construction herein described, all Without departing from the scope of the invention,
it is to be understood that all matter herein set forth or shown in the` accompanying drawing is to be interpreted as illustrative and not in a limiting sense.
1. A sound record tablet having a sound recording surface and a mandrel contacting surface, reinforcing means embedded in said sound record tabletbetween said surfaces, said means comprising open-mashed relatively non-elastic fabric, and unvulcanized elastic rubber covering the strands Without filling the meshes of said open-meshed fabric.
2. A sound record tablet having a sound recording surface and a supporting surface, reinforcing means embedded between said surfaces, said means comprising an open-meshed relatively inelastic fabric, and elastic means separating said fabric from the material ofsaid record, said means comprising a coating of latex rubber surrounding the fibres without filling the meshes of said fabric.
3. A sound record tablet having a sound recording surface and a supporting surface, a reinforcing means embedded between said surfaces, said means comprising an open-meshed, unvulcanized rubber treated relatively inelastic fibre fabric.
4. A sound record tablet having a sound recording surface, a supporting surface, and a reinforcing means embedded between the said surfaces, said means comprising a perforate unvulcanized rubber treated relatively inelastic material. i
LELAND D. NORTON.