US2577149A - Corundum phonograph needle and sound reproducing apparatus embodying same - Google Patents

Corundum phonograph needle and sound reproducing apparatus embodying same Download PDF

Info

Publication number
US2577149A
US2577149A US761812A US76181247A US2577149A US 2577149 A US2577149 A US 2577149A US 761812 A US761812 A US 761812A US 76181247 A US76181247 A US 76181247A US 2577149 A US2577149 A US 2577149A
Authority
US
United States
Prior art keywords
needle
point
corundum
record
phonograph
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US761812A
Inventor
John F Pelton
Thomas F Hart
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Union Carbide Corp
Original Assignee
Union Carbide and Carbon Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Union Carbide and Carbon Corp filed Critical Union Carbide and Carbon Corp
Priority to US761812A priority Critical patent/US2577149A/en
Application granted granted Critical
Publication of US2577149A publication Critical patent/US2577149A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B3/00Recording by mechanical cutting, deforming or pressing, e.g. of grooves or pits; Reproducing by mechanical sensing; Record carriers therefor
    • G11B3/44Styli, e.g. sapphire, diamond
    • G11B3/46Constructions or forms Disposition or mounting, e.g. attachment of point to shank
    • G11B3/48Needles

Description

Dec. 4, 1951 Filed July 18, 1947 J. F. PELTON ET AL CORUNDUM PHONGGRAPH NEEDLE AND SOUND REPRODUCING APPARATUS EMBODYING SAME INVENTORS JOHN F. PELTON BY THOMAS F. HART ATTORNEY Patented Dec. 4, 1951 'CORUNDUM PHONOGRAPH NEEDLE AND SOUND REPRODUCINQ APPARATUS r nvn BODYING SAME John F. Pelton, Kenmore, and Thomas F. Hart, ..Bufialo, N. Y., assignors, by mesne assignments, to Union Carbide and Carbon Corporation, a
corporation of New York Application July 18, 1947,,Serial No. 761,812
This invention relates to extending the playing lives of unicrystalline corundum phonograph needles, especially needles of the composite type wherein a. small unicrystalline corundum point is secured in the end of a shank of different material, such a metal or plastic.
Composite phonograph needles having unicrystalline corundum points, such as natural or synthetic ruby and sapphire, have been used extensively in recent years. Because of their great hardness such needles theoretically should have extremely long playing lives. It has been found, however, that ruby and sapphire needle points are quite erratic in behavior, some having relatively long lives and others failing in service after only relatively short periods. When premature failure occurs it is usually by the spalling or chipping of particles from the needle points rather thanby ordinary abrasion. This problem has been of considerable concern in the art of sound transcription, but attempts to solve it met with little success prior to the present invention. The principal object of this invention is to extend and make more uniform the playing lives of phonograph needles having unicrystalline corundum points.
In the drawing Fig. 1 is a schematic perspective view showing a corundum phonograph needle point in playing position on a phonograph record, the size of the needle point being considerably exaggerated;
Fig. 2 is an enlarged side elevational view, parts being in section, of a composite phonograph needle mounted in playing position in a phonograph tone arm; and
Fig. 3 is an enlarged front elevational view of the phonograph needle shown in Fig. 2. We have found, surprisingly, that the life of a composite sound reproducing needle N having .a unicrystalline corundum point II can be lengthened considerably by properly positioning the needle on a laterally modulated record R so that two conditions are observed with reference to the crystallographic c-axis cc of the needlev is in contact with the record (approximately nor-v mal to the record radius) a .As a practical commercial matter, it is not 8 Claims. (01. 274-38) possible to fulfill both of the above conditions perfectly on all needles, but a variation of plus or minus 15 degrees in either or both conditions. can be tolerated without sacrificing much in the uniformity and extent of life of the needles.
The necessity for observing both of .the abovedescribed conditions-is emphasized by the following results of a series of accelerated life tests. conducted on a large number of. composite needleswith sapphire points mounted in metal shanks and carried in a tone arm'which exerted a needle force of 1% ounces on dis-c type record R.
A. Of the needles which were so mounted that both of the above described conditions No. 1 and. N0. 2 were observed Within plus-or minus .15 degrees, 88%-were still in satisfactory condition after 300 minutes of playing time.
B. Of the needles which were so mounted that. the c-axis cc'was approximately parallel to the record within plus or minus 15 degrees (condition No.1), but that the cg plane was inclined at an angle of more than 15 degrees to the tangent to the record groove, only. 50% were still in satisfactory condition after 300 minutes of playing,
time...v
C. Of the needles which were so mounted that. thecg plane was approximately tangent to.the record groove within plus or-minus 15 degrees (condition No. 2), but that the c-axis ccwas inclined at an angle of more than 15 degrees to. the record, only 30% were still in satisfactory condition. after 300 minutes of playing time.
D. Of the needles which were so mounted thatv neither of the above described conditions No.1 and No. 2 was observed within plus or minus 15 degrees, only 10% were satisfactory after 3.00 minutes of playing time. Many of the unsatisfactory needles failed after much less than .300. minutes, in several instances lasting for less than 30 minutes.
In all of the above tests, the points of the un-. satisfactory needles were too badly chipped or spalled to be used longer.
Deviations of the c-axis cc and the cg plane of morethan 15 degrees from one or both of the two critical conditions No. l and No. 2 cause a sudden large decrease in the percentage of satisfactory needles. For example, of a group ofneedles wherein the deviation from the optimum of one orboth conditions was between 15 and .30 degrees (but neither condition greater than 30. degrees) only 67% were satisfactory .in life tests comparable to those described above.
It is apparent that on an extra large disc type record or on a record wheretheradius of the rec,
6rd groove is infinitely large, for example a recording tape, tangency of the ca plane to the groove is then for practical purposes identical with parallelism to the groove and condition No. 2 is fulfilled by positioning the needle point so that-thefcg plane is parallel to the record groove.
The average user of phonograph needles has no facilities for determining the position of the c-axis in a corundum needlepoint. Tomake available to the public the advantagesofour in" vention, therefore, it is essential for the manufacturer of phonograph needles tomount the table 23 when the point is aligned with the edge,
ing-of the needlepoint when a. record is placed on corundum needle point II in ashank l fi inisuch a way that conditions No. 1 and N612 iwill neces sarily be observed by the ultimate consumer when he mounts the needle in his tone, arm or pick-up T. This is done by providing each needle FT with a suitable index so disposed with reference to the cg plane of the point II and the c-axis direction of the point that when the needle is positioned in a phonograph tone arm with the index in a position determined by a prearrangedcode of instructions the cg plane is approximately tangent to the groove or sound track 13 of a record R. to be played,- and the c axis c-'-c of the point is approximately parallel to the record. Any suitable index may be used, for example an indentation, a surfacemark, or a hole;
A convenient andv practical index is the set screw seat of the needle which generally is a flattened side of the needleshank as shown'at H in Fig. 2. In most modern phonographs the needle set screw 19 is located horizontally in the extreme end of the tone arm '1,- and the needlesOcketZl" is iinclinedat' an angle of about 65 to the record R, in the direction of record rotation. In most cases, therefore, the proper positioning of the needle is assured when the corundum point II is so set in the lower end of shank that the airplane of the point approximately bisects the set screw seat H, as shown in Fig. 3, and the c-axis cc' forms an angle of about 65" with the longitudinal aXisL-L of the top'portion ofshank I5 on the side of the longitudinal axis remote from set screw seat H.
Manyrdifferent shapes of set screw seats can be used, such as flat; concave, grooved; or V shaped. However, the usual set-screw seat is fiat as shown at I1, so that the proper setting of most needle points in their shanks requires that the cg plane be approximately normal to such a flatseat;
When an index as described above-isprovided, proper positioning of the needle point on the'rec-" 0rd is independent of the needle shape. Both straight needles and needles having simple and complex curvatures can be positioned-properly.
In the case of the popular S=shaped needles,
.such as the needle N illustrated in Fig. 2,-the
plane of the S-curve is normallymaintained approximately tangent to the record groove l3 when the needle is in playing position. Iii such a needle the advantages of the present invention are provided by so setting point 1| in shank [5 that the cg plane approximately parall'els the plane of the S-curve and the .c-axis c c lies at about to the longitudinal axis IJI3 of the upper portion of shank 15 on the-side ofaxis and the c -axis cc is approximately parallel to the top of the turntable. Thus, proper positiontne turntable is assured.
We'claim: V I .A .phonog'raplii needle comprising a shank -having a= set 'screwseat on a side adjacent the top thereof? and a unicrystalline corundum point carried-by said shank at the bottom thereof, said point being so positioned that the co plane of said point approximately bisects said seat, and that the c-axis of said point and the longitudinal axis of the top portion of said shank form an angle of about 65 with one another on the side of said longitudinal axisremote from said seat.
.2; A g phonograph needle comprising 7 a shank having affla't set screw seat on a side thereof adjacent the top thereof; and a unicrystalline corundum point carried by said shank at'the bottom thereof, said point being so positioned that-the cg plane of said point is approximately normal to said flat seat, and that the c-axis of said point and the longitudinal axis: of the top portion of said shank form anangle of about 65 with one another on the side of said longitudinal axis remote from said flat seat.
3; A phonograph needle comprising a'shank' having a plane S curve, and a unicrystalline corundum point carried by said shank at the bottom thereof, said point being so positioned that-the cg plane of said pointparallels the plane of said S-curve, :and that the c-axis of said point and the longitudinal axis of the top portion of said shank form an angle of about 65 with oneanother onthe side of said longitudinal axis remote from said point.
4-. A phonograph needle comprising a shank having a top for insertion in the tone armof a; phonograph and a unicrystalline co'rund'umpoint at the bottom of said shank, said needle having anindex thereoniso disposed.- with reference; to ithe cg. plane of said' pointand the c'-'axis pOSition of said point that when said-needle is post; tioned in a phonograph tone arm with said index in a'position determined by. a' prearranged code, the cg plane of' said point is approximately tangent to the sound track of a record to be played; and'the e-axis of said point is approximately parallel to'such record. I
5.-In a phonograph having a'rotatable record table and a tone arm having a needle socket, a needle adaptethto cooperate with a record onsaid table, saidneedle comprising a shank extending'upwardly. into said socket and a uni-; crystalline corundum point at the bottom of said shank,- said point being so positioned that the 6- axis thereof is approximately parallel to said tableand that the co plane'of said point is approximately tangent to the edge of'sa'id table; when said point is aligned with said edge.
6; In sound reproducing apparatushaviiig a. phonograph record provided with'a' sound track, a unicrystalline corundum phonograph needle" hailing a pointriding in said sound track thecg plane or said needle beingapproximately tangent: to said sound track at the pointer contac'tfiofi said needle .with' saidrecord; the .oi-axis of said needle being approximately parallel to said rec--l rd.
7. In sound reproducing apparatus having a' rotatably mounted disc type phonograph record provided with a spiral sound track, a unicrystalline corundum phonograph needle having a point riding in said sound track, the cg plane of said needle being approximately tangent to said sound track at the point of contact of said needle with said record, the c-axis of said needle being approximately parallel to said record.
8. In a phonograph having a rotatable record table and a tone arm carrying a needle adapted to cooperate with a record on said table, said needle comprising a unicrystalline corundum point, the cg plane of said point being approximately tangent to the edge of said table when said point is aligned with said edge, and the caxis of said point being approximately parallel to said record.
JOHN F. PELTON. THOMAS F. HART.
3 REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,737,253 Linsell Nov. 26, 1929 2,265,601 Imelmann Dec. 9, 1941 2,276,562 Capps Mar. 17, 1942 2,320,416 Dally June 1, 1943 2,328,889 Capps Sept. '7, 1943 2,346,733 Dally Apr. 18, 1944 2,355,877 Le Van Aug. 15, 1944 FOREIGN PATENTS Number Country Date 751,047 France Aug. 25, 1933 duction Reaches Commercial Scale in U. S., October, 1943. (Four pages. Copy in Division 5.)
US761812A 1947-07-18 1947-07-18 Corundum phonograph needle and sound reproducing apparatus embodying same Expired - Lifetime US2577149A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US761812A US2577149A (en) 1947-07-18 1947-07-18 Corundum phonograph needle and sound reproducing apparatus embodying same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US761812A US2577149A (en) 1947-07-18 1947-07-18 Corundum phonograph needle and sound reproducing apparatus embodying same

Publications (1)

Publication Number Publication Date
US2577149A true US2577149A (en) 1951-12-04

Family

ID=25063328

Family Applications (1)

Application Number Title Priority Date Filing Date
US761812A Expired - Lifetime US2577149A (en) 1947-07-18 1947-07-18 Corundum phonograph needle and sound reproducing apparatus embodying same

Country Status (1)

Country Link
US (1) US2577149A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3844566A (en) * 1971-12-20 1974-10-29 Gte Automatic Electric Lab Inc Transcribing device
US4065134A (en) * 1975-12-02 1977-12-27 The Astatic Corporation Needle assemblies for phonograph pickup cartridges

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1737253A (en) * 1926-10-02 1929-11-26 Rca Corp Means for recording and reproducing sound
FR751047A (en) * 1933-02-17 1933-08-25 Pick-up refinements
US2265601A (en) * 1940-12-30 1941-12-09 Permo Products Corp Recording stylus
US2276562A (en) * 1940-07-09 1942-03-17 Frank L Capps Sound recording stylus
US2320416A (en) * 1941-06-23 1943-06-01 Webster Electric Co Inc Stylus for reproducers
US2328889A (en) * 1942-06-18 1943-09-07 Frank L Capps Sound reproducing stylus
US2346733A (en) * 1941-01-18 1944-04-18 Webster Electric Co Inc Tone arm
US2355877A (en) * 1942-08-18 1944-08-15 Hamilton Watch Co Processing crystalline structures

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1737253A (en) * 1926-10-02 1929-11-26 Rca Corp Means for recording and reproducing sound
FR751047A (en) * 1933-02-17 1933-08-25 Pick-up refinements
US2276562A (en) * 1940-07-09 1942-03-17 Frank L Capps Sound recording stylus
US2265601A (en) * 1940-12-30 1941-12-09 Permo Products Corp Recording stylus
US2346733A (en) * 1941-01-18 1944-04-18 Webster Electric Co Inc Tone arm
US2320416A (en) * 1941-06-23 1943-06-01 Webster Electric Co Inc Stylus for reproducers
US2328889A (en) * 1942-06-18 1943-09-07 Frank L Capps Sound reproducing stylus
US2355877A (en) * 1942-08-18 1944-08-15 Hamilton Watch Co Processing crystalline structures

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3844566A (en) * 1971-12-20 1974-10-29 Gte Automatic Electric Lab Inc Transcribing device
US4065134A (en) * 1975-12-02 1977-12-27 The Astatic Corporation Needle assemblies for phonograph pickup cartridges

Similar Documents

Publication Publication Date Title
US4199782A (en) Stylus for reproducing capacitive videodisc
US2577149A (en) Corundum phonograph needle and sound reproducing apparatus embodying same
US2259715A (en) Sound record
US3023011A (en) Phonographic recording
US3184242A (en) Recording stylus
US4113267A (en) Double stylus assembly for phonograph record stamper playback
US3774918A (en) Phonograph pickup stylus
US1110428A (en) Process of forming phonograph-styli.
US2819089A (en) Recording method using translating head and stylus
US2544495A (en) Stylus construction
US2026760A (en) Sound reproducing or recording needle
US1739201A (en) Phonograph needle
US1041983A (en) Phonograph-stylus.
US1976560A (en) Method of recording sound
US1580567A (en) Sound record for talking machines
US1718035A (en) Sound-reproducing needle
US4497052A (en) Stylus for reproducing information signals recorded on a recording medium
US3383752A (en) Method of preparing styluses for reproducing phonograph records
US1368745A (en) Method of making record-tablets
US3871664A (en) Phonograph stylus
US1349009A (en) Phonograph-needle-sharpening attachment
US778975A (en) Cutting-tool for sound-recording machines.
US3390888A (en) Recording device
US1856428A (en) Phonograph
US1439718A (en) Phonograph