US2613938A - Backspacing mechanism - Google Patents

Backspacing mechanism Download PDF

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US2613938A
US2613938A US773823A US77382347A US2613938A US 2613938 A US2613938 A US 2613938A US 773823 A US773823 A US 773823A US 77382347 A US77382347 A US 77382347A US 2613938 A US2613938 A US 2613938A
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gear
motor
backspacing
feed screw
drive
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US773823A
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Charles L Bossmeyer
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Dictaphone Corp
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Dictaphone Corp
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    • 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
    • G11B3/02Arrangements of heads
    • G11B3/10Arranging, supporting, or driving of heads or of transducers relatively to record carriers
    • G11B3/34Driving or guiding during transducing operation
    • G11B3/36Automatic-feed mechanisms producing progressive transducing traverse across record carriers otherwise than by grooves, e.g. by lead-screw
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T74/00Machine element or mechanism
    • Y10T74/19Gearing
    • Y10T74/19949Teeth
    • Y10T74/19963Spur
    • Y10T74/19967Yieldable
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T82/00Turning
    • Y10T82/25Lathe
    • Y10T82/2531Carriage feed

Description

@t. 14, 1952 c. L. BOSSMEYER 2,613,938
BACKSPACING MECHANISM Filed Sept. 13, 1947 4 Sheets-Sheet l I N a a (Y) mvzmoa N Charles L. Bossmeyer BY W340 0% M, 1952 c. BOSSMEYER 2,513,938
BACK-SPACING MECHANISM Filed Sept. 13, 1947 4 Sheets-Sheet 2 IIIHHH] l WW" I I l r l r l I i r I l HHlis.
'INVENTOR Charles Bossme er Oct. 14, 1952 c. L. BOSSMEYER 2,613,933
BACKSPACING MECHANISM Filed Sept. 15. 1947 4 Sheets-Sheet 3 iOO TTEJL.
INVENTOR 94 v Charles L. ,Bagsmeyer se Al IIIII 'IIIIII);
ATTOR EYS Patented Oct. 14, 1952 Charles L. Bossmeyer, Rockford,--Ill., assignor to Dictaphone Corporation, Bridgeport, Conn., a corporation of New York Application September 13, 1947, Serial No. 773,823
4 Claims.
This invention is described in relation to variable speed sound reproducing equipment and in such equipment more particularly to a commercially practicable backspacing construction by which the sound reproducing element may quickly and automatically be caused to assume a position from which to repeat a predetermined amount of the recording being reproduced. Recording and reproducing equipment generally is well known and has commonly been used by typists and the like while making written transscriptions of recorded material. Sometimes while making such transcriptions it becomes necessary to have repeated a brief portion of the recording. I am aware that various backspacing mechanisms for accomplishing such repetitions have heretofore been offered. I have devised a novel power transmitting construction which is ideally suited to rapid performance of intermittently desired backspacing operations and which is readily adaptable to other applications which will suggest themselves to those skilled in the art of mechanical power supply and transfer.
In United States Patent No. 2,318,828 to Yerkovich and No. 2,371,116 to Yerkovich et al. there are described certain generally similar machines capable of recording on an endless belt of paperthin pliable plastic material and of reproducing the recordings made on such belts. During recording, one of these belts is stretched between a pair of pulleys, or mandrels, each of a diameter of about 2 in. in the illustrative embodiments, mounted for rotation about substantially parallel, horizontally disposed axes spaced about 2% in. apart. One of the two m'andrels is driven and is known as a drive mandrel; the other is free to rotate about its axis and is known as an idler mandrel. The idler mandrel is yieldably mounted so as to hold the recording belt under a small amount of tension against the surface of the drive mandrel.
In the above-mentioned Yerkovich et al. patent the mandrel axes of rotation are disposed in substantially the same horizontal plane. A sound recording head and a sound reproducing head are independently associated with the mandrels for movement through independent paths, parallel to the axes of the mandrels and transversely with respect to the path followed by the surface of the recording belt. Thus a stylus held in the recording head is enabled to impress a sound groove onto the moving belt. And as the belt moves, the recording head is moved transversely at a low constant speed across the surface of the belt so that the groove begins at one side 2 edge of the belt and proceeds around and around the belt and finally ends at the other side edge of the belt. The speed ratios, between linear velocity of a point on the surface of the belt and linear velocity of the recording head as it travels transversely with respect to the movement of the belt, are such that the belt makes 200 complete revolutions while the stylus moves transversely a distance of one inch. Thus the surface of the recording belt, after a sound groove has been impressed upon it, bears a succession of closely spaced loops the distance from the bottom of one groove trough to the bottom of the next adjacent groove trough being approximately .005 in.;
It is apparent, of course, that the closer the spacing of the loops of the sound groove the greater the number of loops that may be contained on a belt of a given size and accordingly the greater the amount of recorded material that may be impressed upon that belt. Mechanical complications and the finite width of the sound groove per se set a practical limit upon the closeness of adjacent loops.
In the embodiment disclosed in the Yer'kovich patent the linear velocity of a point on "the recording belt during normal reproducing is disclosed as being on the order of 20 feet per minute. Thus, in ordinary usage, when the auditor who is listening to the recording misses a word or a phrase, she probably will not want a greater amount repeated than is contained in a single sound groove loop on the recording belt. And if the auditor backspaces the reproducing head with respect to the surface of the recording belt a distance, for example, of as much as & of aninch it results that she has backspaced a matter of ten sound groove loops, which is surely very much more than she wants repeated. An error in backspacing movement of as much as in. will result in a repetition of twice as much as the auditor intends.
Another complication is introduced by the fact that these machines are commonly used to record a message at a point of origin, to relay the message over a communication channel to a point of destination and there to rerecord the message and repeat it to a transcriber or auditor. For coding purposes, and to make the most efficient use of the communication channel, it is the regular practice to transmit the recorded material over the channel at a rate several times greater than that at which the recording was made. In order to accomplish such transmission the machines are equipped with variable speed motors having a range on the order of 10:1. Thus, a
conversation or message recorded at a rate of 150 words per minute might be transmitted at a rate of 1000 words per minute. And the machine at the point of destination must be capable of rerecording at such higher rate and reproducing for transcribing purposes at a rate even below that of the original.
It is obvious that where backspacing accuracy must bein terms of a few thousandths of an inch, the speeds of movement of the parts must be below certain limits or their inertia, Will introduce such variances as to render the mechanism undependable. And if the structure is designed for efficient operation at the higher motor speeds, a disproportionate period of time will be consumed by each operation when the motor is running at lower speeds. Thus, whereas a backspacing operation completed in one half a second might be wholly satisfactory to a typist, a delay of even two secondsonly a 4:1 reduction in motor speed-might after a period of transcribing become an excessive annoyance. A reduction on the order of 4:1 for transcribing would not be unusual in the routine conduct of business quite apart from the channel transmission capabilities of the equipment.
Accordingly it will be understood that a satisfactory backspacing mechanism for a modern machine such as referred to not only must accurately backspace within a few thousandths of an inch but it must perform its function without appreciable passage of time regardless of the speed setting of the main motor or drive mandrel.
Various mechanisms have been suggested and tried in the past for effecting automatic backspacing under such circumstances. I have devised an automatic backspacing construction which will consistently move the reproducing head backwardly with respect to the recording belt a distance of .005 in., or whatever distance may be required for a given machine, and which does so in a negligible time regardless of the number of revolutions per minute being turned by the variable speed drive motor.
I shall describe my invention as it may be applied to a reproducing machine of the general type disclosed in the Yerkovich et al. patent. Accordingly, in-my illustrative embodiment, backspacing of one sound groove will require a transverse movement. of the reproducing head equal to the spacing between adjacent sound groove loopswhere there are two hundred loops to the inch. It is to be noted that the illustrative embodiment of the Yerkovich et al. patent is a recorder-reproducer; for simplicity and to avoid repetition the machine which I have selected to exemplify my invention is a reproducer only.- Machines which will be used only for reproducing omit those parts which are required only for recording. i
It is an object of my invention to provide a device of the character described having to a notable extent the characteristics and capabilities set forth. Another object is to produce a commercially practicable backspacing mechanism which is operable upon demand independently of the main motor drive. A further objective is the provision of a backspacing structure which is both feasible in manufacture and foolproof in operation and which will consistently give the desired extent of backspacing. A further object is to provide a novel sort of gear train mechanism which is useful in turning a shaft through a given angle upon demand. An-
other object is to provide a multiple gear mechanism wherein a certain portion of the gear train may be meshed or unmeshed at will, automatically and without any possibility of jamming the gears which are caused to mesh. Yet a further objective resides in the provision of a backspacer and a gear assembly of general utility which overcome certain disadvantages inherent in the backspacers and gear assemblies of the prior art. Other objectives will be in part pointed out as the description proceeds and will in part become apparent therefrom.
The invention accordingly consists in the features of construction, combinations of elements, methods of operation, and arrangements of parts as will be exemplified in the structure and sequences and groups of related steps to be hereinafter described and the scope of the application of which will be set forth in the accompanying claims.
In this specification and the accompanying drawings I have shown and described a preferred embodiment of my invention and suggested various modifications thereof; but it is to be understood that these are not intended to be exhaustive nor limiting of the invention but, on the contrary, are given for purposes of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in various forms, each as may be best suited to the conditions of a particular use.
In the drawings: Figure 1 is a rear elevation (taken along the line ll of Figure 2) of a sound reproducing machine of the type disclosed in the Yerkovich et al. patent and in which my invention has been incorporated;
Figure 2 is a plan view (taken along the line 2-2 of Figure 1) of the machine;
Figure 3 is a sectional end view taken along the line 33 of Figure 1;
Figure 4 is a fragmentary view on an enlarged scale of a friction clutch assembly which is employed in the machine; 7
Figure 5 is a fragmentary view on an enlarged scale of a mutilated gear assembly which forms a part of the invention;
Figure 6 is a fragmentary sectional view taken along the line B6 of Figure 5;
Figure 7 is a fragmentary View taken along the line 1-1 of Figure 1 showing a part of the backspacing gearing and related mechanisms;
Figure 8 is a sectional view taken along the line 8-8 of Figure 7;
Figure 9 is a fragmentary sectional view taken on an enlarged scale along. the line 99 of Figure 1; and
Figure 10 is a diagrammatic representation of certain of the electrical circuits and some of the parts related thereto.
The machine shown in Figure 1 includes a machine frame 20, which may take the form of a metal casting, and which includes a supporting plate 22 rising from its right-hand end (see Figure 1) and a supporting plate 24 rising from its lefthand end. A relatively heavy fly wheel 26 is disposed in a substantially vertical plane at one end of the machine for rotation about a horizontal axis. Fly wheel 26 is driven by a pair of belts 28 For a more complete disclosure of the motor arrangement and of other conventional aspects of the present embodiment not otherwise detailed herein reference should be made to the disclosure of Yerkovich et al. Patent No. 2,371,116.
The fly wheel is mounted upon a fly wheel shaft 33 (see Figure 1) journaled in supporting plate 22 and carried by the machine frame. Drive mandrel 32 is turned by means of fly wheel shaft 30; since the motor which drives the fly wheel is of the variable speed type the rate at which the drive mandrel is turned is variable in accordance with the motor speed. Ordinarily a constant speed is used throughout any one recording, variations in speed being employed for transcribing purposes to pace the rate of reproduction to the optimum capacity of the typist or auditor. An idler mandrel 34 (see also Figure 2) is disposed'for free spect to the path through which the belt moves' The reproducing carriage is slidable upon a horizontally disposed carriage guide rod it (see Figures land 2) held between supporting plates 22 and 24'. The carriage is caused to slide along the carriage guide rod by a feed screw t2 (see Figure l) positioned in conventional manner within the guide rod. The axis of the feed screw is substantially coextensive with the axis of the carriage guide rod. A feed nut, not shown but held within the carriage, meshes constantly with the feed screw so that rotation of the screw ad" vances or backspacesthe carriage with respect to the recording belt depending upon the direction of rotation of the feed screw.
In normal transcribing the feed screw is driven from the fly wheel shaft by a gear train mechanism, to be described. Feed screw G2 is identical to the feed screw used with the recording carriage.
Hence the reproducing carriage is advanced across themoving belt at a rate which makes it possible for the reproducing stylus to follow exactly the sound groove which was embossed in the belt by the recording stylus. In the described embodimentthe feed screw is rotated through 120' der es while the recording belt is making one revolution. Accordingly, in 'order to backspace one'soundgroove, the feed screw will have to be reversed through an angle of 120 degrees.
As shown in Figure 3, fly wheel shaft 30 drives a fly wheel gear dd held in mesh with an intermediate gear is on an intermediate shaft 48. Gearis maintained in meshing relationship with a second intermediate gear 59 which turns a pinion 52 constantly meshed with a feed screw gear 541; The efiect of this gear train is to reduce the numberof revolutions made by the feed screw gear as compared to the number of revolutions made by the fly wheel shaft.
The drive relationship between feed screw gear 54 and feed screw 42 is not positive. As shown in Figure 4, feed screw gear 54 has secured to its inner face an annular rim 56. This rim may be removed, if need be, by unscrewing machine screws 58. A drive flange til is keyed in driving relationship to feed screw 4 2; feed screw gear 5 is freely rotatable upon a hub 62 of drive flange 6i). Feed screw gear 5& is held in position upon hub 62 by rim 56, which overlaps peripheral portions M of flange 6i Feed screw gear 54 may be removed by removing machine screws 58 so that the gear can be separated from annular rim 56.
A spider spring 86 is also rotatably positioned on hub 62 and is normally compressed between the opposing faces of the inside of gear 54 and the outside of flange 60. Thus the spider spring tends to push gear 56 axially oif of hub 62 but rim 56 prevents any separation more than that shown in Figure 4. Accordingly, feed screw gear 54 is held relatively firmly with respect to flange 60 and ordinarily the driving force imparted to feed screw gear 54 by pinion 52 is transferred through flange 60 to the feed screw to cause operative rotation thereof. The feed screw is mounted for rotation in a feed screw bearing 68 supported within a bearing bushing 79 conventionally held within carriage guide rod ii). The carriage guide rod, as pointed out previously, is nonrotatably fixed between supporting plates 22 and 24.
In the present embodiment, as disclosed in Figure 3, I provide a small self-starting motor 72 (see also Figures 1 and 8) this motor I use, as will be described, to effect reverse rotation of the feed screw. The motor (see Figure '7) drives a spur gear i i mounted upon a motor countershaft it which drives a bevel gear 18 held in meshing relationship with a bevel gear 83 which gear in turn is locked to and drives a shaft 82 (see also Figure 3). A gear 84 driven by shaft 32 is in mesh with and drives an intermediate gear 85 which in turn meshes with and drives a spur gear 88. which is broken away in Figure 3 to show gear 83 juxtaposed thercbehind) is disposed coaxially with respect to gear 83 and is rotated thereby.
Mutilated gear 9!) is arranged to mesh with an intermediate gear 92 which gear is in mesh with a backspacing gear 9 solidly secured to flange (it (see also Figure 4). During ordinary operation of the transcribing equipment a mutilated portion of gear fit, as will be described, faces gear 92 so that there is no driving relationship therebetween and accordingly feed screw 62 is driven through the friction clutch between gear 5% and flange fill. However, when it is sought to effect a backspacing operation, the small electric motor '12 is energized, as will be described, and the train of gears including members i6, i8, 88, 8 1, 85 and 83 comes into operation to move mutilated gear so into meshing relationship with gear 92 tocause reverse rotation of backspacing gear 8 t. During the reverse movement of gear 94 the main machine motor continues to drive the fly wheel and accordingly a slipping occurs between flange Gil (now moved by gear 9d) and gear 55 (driven from the fly wheel). The energization of motor i2 is of limited and predetermined duration, as will be developed hereinafter, so that'thereverse movement of backspace gear 94 extends through degrees. As will be described, gear 92 is then again unmeshed from mutilated gear 90.-
It is to be observed that the fly wheel turns at its ordinary speed whether a backspacing operation is occurring or not and accordingly the train of gears which ordinarily drives the feed screw continues to operate at its normal rate of speed. When a backspacing operation is called for, however, the drive is broken at the frictional coupling and the backspacing mechanism takes precedence as it meshes with moving gear 92 to effect the intended backspacing operation.
Because normal fly wheel operation is uninterrupted some provision must be made for enabling the backspacing mechanism to be meshed into the drive to the feed screw. Since there is no interruption of the main .motor, it is obvious that ordinary gearing, Geneva mechanisms, and
A mutilated gear $30 (a part of the like would jam unless the engaging parts happened by chance to fall into mesh. It is equally evident that the backspacing movement must be of a measured amount which can invariably be imposed at will upon the normal drive and which will be independent of the speed adjustment at which the normal drive is running. I have discovered that the mutilated gear may be made to mesh properly with gear 92 each time power is supplied to the backspacer motor by providing the mutilated gear with a flexible feeler 95 which is clamped in place by a clamp screw 98 on the peripheral portions of gear 90. The feeler is formed in the present embodiment from stifi wire similar to piano wire and has a cross sectional diameter which is approximately equal tothe chordal thickness of one of the teeth of the mutilated gear. The feeler is provided at its outer end portion with a detent I formed by a right angle bend in the wire. The axis of this detent is substantially parallel to the axis of rotation of the gear. The feeler is so adjusted and held in place by clamp screw 98 that detent I00 occupies approximately the region in space that would be occupied by the working part of a tooth of gear 90 if there were another tooth beyond tooth I02. Actually, the detent is adjusted so as to extend slightly beyond the outside diameter of the toothed portion of the mutilated gear. In addition, the detent is spaced from tooth I02 slightly more than the normal spacing between two adjacent gear teeth. The location shown of clamp screw 93 with respect to tooth I02 and the configuration of feeler 99 are such that as the mutilated gear rotates toward meshing relationship with gear 92, the first contact made is between detent I00 and some tooth portion of gear 92. With the arrangement shown, the inherent flexibility of feeler 96 is such that even if the detent should in the first instance be squarely abutted against an outer end of a tooth, the detent will yield inwardly toward the center of the mutilated gear and, as the approaching gears tend to move at diiferent peripheral rates, will find its way into the solid line position illustratedin Figure 6 between two of the teeth of gear 92. When the detent assumes the location illustrated, gears 90 and 92 are oriented so that the rigid teeth will mesh perfectly. Thus, no matter what the angular relationships between and peripheral speeds of the umneshed gears may be, when a driving force of rotation is applied to the mutilated gear, feeler 96 and detent I00 automatically align the teeth of gears 90 and 92 so that they are brought into proper mesh. Gear 90 is relieved by a clearance groove I04 across its edge into which the detent may upon occasion enter.
When a backspacing operation is called for, the feed screw must be turned backwardly rapidly through 120 degrees. Hence, gear 92 must be r0- tated through a finite number of degrees and to do this there must be a certain number of teeth in the toothed portion of the mutilated gear in order that gear 92 shall be turned through the correct angle. In the embodiment here described (see Figure 3) the mutilated gear is provided with two toothed portions, each portion having ten teeth, and each portion is provided with an advance feeler 96 carrying a detent I 00. The detent serves as an additional tooth, making eleven operative teeth on each side of the gear. And the mutilated gear must be turned through 180 degrees to bring the eleven effective teeth of one of its toothed portions into and out of mesh with the opposing teeth of gear 92 so as to turn the feed screw backwardly through 120 degrees. Thus with a single backspacing operation, eleven teethof gear 92 are caused to reverse the direction of normally ineffective backspacing gear 94 (see also Figure 4). The friction clutch between feed screw gear 54 and backspacing gear 94 has a damping effect on any overrunning which might otherwise occur from the inertia of the parts so that when the eleven teeth of gear 92 have done their work there is a clean break from the backspacing movement and gear 94 now finds itself displaced backwardly through the friction clutch an accurately measured, predetermined amount. The feed screw also, of course, has been turned back through the same measured amount. The overall time cycle required for a complete operation and the amount of feed screw reverse displacement remain constant under all conditions and are accomplished independently of the speed at which the variable speed motor is turning.
The backspacing gear train is such that for one-half a revolution of countershaft I6 there follows a one-half revolution by the mutilated gear. One end of countershaft I6 carries a timing cam I06 (see Figure 8 Cam I06 is provided with a pair of diametrically spaced dwells I08. During ordinary transcribing operation, a foot IIO of a normally open short travel limit switch II2 occupies the space within one of the cam dwells I08. When the backspacer motor circuit is closed, however, and countershaft I6 is caused to rotate, the rise on cam I06 comes into engagement with foot H0 and switch II2 closes a holding circuit which, once closed, remains closed until motor "I2 has turned countershaft 16 through 180 degrees again to present a dwell I08 to foot IIO so as to enable holding switch II2 to open and de-energize the backspacer motor circuit. Thus, a momentary closing of the backspacer motor circuit suflices to initiate movement of countershaft 16 and thereafter, through the action of holding switch I I2, the backspacer motor continues automatically to operate the exact length of time required not only to turn countershaft I6 through 180 degrees but also to turn mutilated gear through 180 degrees and accordingly to turn feed screw 42 backwardly through degrees. During such operation of the backspacer motor and by virtue of the frictional coupling which is incorporated in the variable speed motor drive to the feed screw the variable speed motor continues to operate. As soon as the backspacer motor has caused the feed screw to reverse through 120 degrees ordinary transcribing motion is restored to the feed screw automatically and without pause.
When feed screw 42 is reversed, reproducing carriage 38 is caused to move to the left, as shown in Figure 2, by one sound groove loop. It is desirable that the reproducing stylus which ordinarily rides in the sound groove be lifted from the surface of the recording medium while the reproducing carriage is being backspaced. Accordingly I provide mechanism which automatically synchronizes with a backspacing operation to lift the stylus of the reproducing carriage off of the surface of the recording medium at the beginning of a backspacing operation and to set it down gently at the end of a backspacing operation.
As shown in Figure 3, gears 88 and 90 are located upon a shaft I I4 (see also Figure 2). This shaft includes an extended portion II 6 which reaches behind reproducing carriage 38 even when this carriage is in its extreme right-hand position.
' Portion H throughout its length behind the path of travel of the reproducer carriage has a non-circular cam-like cross section (see also Figure 9). The reproducer carriage is provided with a bracket IIB '(see Figure 9) which includes an opening I2!) through which cam-like portion III; extends. Bracket IIB serves as a pivot support for a bell crank lever I22 (see Figure 9) normally urged by gravity in a counterclockwise direction so that its upper arm I24 bears slidably upon the flat vertical face of portion IIii as the reproducing carriage is moved by. the feed screw during normal operation. However, when a backspacing operation is instituted and shaft 2 I4 and itscamlike portion Ht are caused to turn, bell crank lever I22 is caused to rotate through a small angle in a clockwise-direction and is there held until portion I I5 is turned through 180 degrees. While the bell crank lever is held against gravity in its clockwise position, its other arm I26 is raised somewhat from the position illustrated in Figure 9 and in its raised position it is in lifting contact with the underside, of the bottom edge of transducing cartridge I28 of the reproducing carriage. The stylus is conventionally mounted in this cartridge and is held elevated slightly off the recording medium during the period while bell crank lever 522 occupies its clockwise position. It is during this period that the feed screw is rotated backwardly. This construction obviously raises and lowers the stylus with a smooth, gentle motion which cannot damage the delicatepoint.
As shown in Figure 8, a normally closed low travel limit switch Hit is fixed in position near switch II2 with its switch-throwing button I32 so disposed as to be engaged and actuated by the head of a screw I34 (see Figure 2) mounted in the left-hand face of the reproducing carriage. The position of screw I34 with respect to the reproducing carriage may be adjusted and locked by an adjustment nut I36. Thus, when carriage 3B is moved to its most left-hand position at the beginning of a reproducing operation, screw I3 1 is brought into contact with button I32 so as to open switch I33. With switch I30 open the circuit. of the backspacing motor is open so that a backspacing operation cannot be instituted;
.switch liiiiwill not close until the reproducing carriage is moved from its most left-hand position. In this manner it is made impossible for the backspacing motor to be energized unless the reproducing carriage is in a position from which it may be backspaced without jamming.
Figure indicates diagrammatically the electrical circuit of the backspacing motor. As here shown, a backspacing operation is instituted by momentarily closing a normally open switch I38. Ordinarily this switch is arranged for foot operation. When switch I33 is closed current flows from a supply line I i-Il through a branch line I42, switch I33, normally closed safety switch I38, and branch lines EM and Hit into motor I2, thence to a branch line H58 and back to main line I553. When switch 333 is closed motor I2 starts and cam Hit immediately operates to close holding switch IIZ. Power is then available through branch line its to branch line Hi6 and thence through the motor and line MS to line I50. Thus, when the starting switch is closed, holding switch II2 assures that a complete backspacing operation is accomplished. When the reproducing carriage is moved to its most left-hand position, however, screw ifi l comes into contact with button I32 and opens switch I30. As long as switch I3B is open nothing is accomplished by closing switch I38 and so backspacing is'prevented until such time as the reproducingcarriage is moved to a position from which it may be backspaced without jamming. i
From the foregoing it will be seen that a backspacing structure made in accordance with the present invention is well adapted to attain the ends and objects hereinbeforeset forth and to be economically manufactured since the several parts and assemblies are suited to common production methods and are susceptible to a wide latitude of variations as may be desirable in adapting the invention to different applications.
As various embodiments may be made of the above invention and as changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying'drawings is to'be interpreted as illustrative and not in a limiting sense.
I claim: I v
1. In adjustable speed sound reproducing equipment of the type wherein a translating element follows a continuous sound track disposed in closely spaced loops on the surface of a driven recording medium: a reproducer carriage mechanism in which the translating element is'supported, the mechanism being disposed for travel along a path transverse with respect to the direction of the sound track loops, a feed screw'meshed with the mechanism and rotatable to advance-or backspace it along the path, an adjustable speed motor and drive connected to rotate the feed.
screw at a selected speed in the direction-which advances the mechanism, ahigh speed backspace motor and drive, an intermediate mechanism disposed between the backspace drive and the feed screw and operable by the backspace-drive to rotate the feed screw in the other direction-and a control system regulating energysupply'to the I motors; said system including a normally'closed supply line to the adjustable speed :motor, a normally open supply line to the backspace-motor, a switch in the backspace supply-line for closing the circuit therethrough, a normally open holding switch in parallel around the closing "switch, and a coupling arranged to close"th'e holding switch'when the backspace :r'notor is energized and to hold it closed through a predetermined backspace motor movement. Y 2. In adjustable speed sound reproducing equipment of the type wherein a translating element follows a continuous sound track disposed in closely spaced loops on the surface of a driven recording medium: a reproducer carriage mechanism in which the translating element is supported, the mechanism being disposed for travel along a path transverse with respect to the direction of the sound track loops, a feed screw meshed with the mechanism and rotatable to advance or backspace it along the path, a drive unit including a portion positively coupled to the feed screw, a high inertia type recording medium supporting and driving assembly associated with said reproducer carriage mechanism for moving the recording medium with respect to said path, an adjustable speed motor having a range of from low speed to a high speed at least several times that of the low speed coupled to said recording medium assembly, a power take-01f assembly coupled to said recording medium assembly and in drivable relationship with said drive unit to rotate the feed screw at a selected speed in a direction which advances the mechanism, a backspace motor of high speed as compared to the lower speeds of said adjustable speed motor and low inertia as compared to said supporting and driving assembly, said motor being disposed adjacent said feed screw and directly and positively engageable upon demand with said drive unit to rotate the feed screw in the other direction independently of the operation of said adjustable speed motor, and a backspace control assembly operative between said backspace motor and said drive unit predetermining the drive of said backspace motor upon initiation of a backspace operation.
3. In sound reproducing apparatus of the type wherein a translating element follows a con-. tinuous sound track disposed'in closely spaced loops on the surface of a recording medium, in combination: a variable speed reproduce drive motor effectively variable in speed through a range of from low speed to a high speed of at least several times that of the low speed, reproduce drive mechanism actuated by the drive motor and coupled to produce relative movement between the translating element and recording medium, a backspace drive motor having an effective speed substantially higher than the lower speeds at which said reproduce drive motor may be run, backspace drive mechanism actuated by the backspace motor and coupled to effect a backspacing movement of the translating element with respect to the recording medium, said reproduce drive motor being supplied with power normally to run without interruption at an adjusted speed, said backspace drive motor being supplied normally with power only when a backspacing movement is demanded, each of said drive mechanisms being disposed in driving relationship to a common driven member, the drive between said backspace motor and said driven member including a segmental gear normally out of mesh with but in drivable relationship to another gear effective upon said driven member, and a backspace control assembly operative between said backspace drive motor and said driven member predetermining the drive of said back space drive motor upon initiation of a backspace operation.
4. In sound reproducing apparatus of the type wherein a translating element follows a continuous sound track disposed in closely spaced loops on the surface of a recording medium, in
combination: a variable speed reproduce drive motor effectively variable in speed through a range of from low speed to a high speed at least several times that of the low speed, reproduce drive mechanism actuated by the drive motor and coupled to produce relative movement between the translating element and recording medium, a backspace drive motor having an effective speed substantially higher than the lower speeds at which said reproduce drive motor may be run, backspace drive mechanism actuated by the backspace motor and coupled to effect a backspacing movement of the translating element with respect to the recording medium, said reproduce drive motor and mechanism incorporating a high moment of inertia compared to that of the backspace drive motor and mechanism and being supplied with power normally to run Without interruption at its adjusted speed, said backspace drive motor being supplied normally with power only when a backspacing movement is demanded, each of said drive mechanisms being disposed in driving relationship to a common driven member, said driven member being part of an assembly operative to effect relative movements of the translating element with respect to the recording medium, whereby such relative movement caused by the backspace drive motor occurs at a rate which is high as compared to relative movement caused by the reproduce drive motor when adjusted to a relatively low speed in its range, and a backspace control assembly operative between said backspace drive motor and said driven member predetermining the drive of said backspace drive motor upon initiation of a backspace operation.
CHARLES L. BOSSMEYER.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 694,784 Ramsay Mar. 4, 1902 2,145,498 Stockton Jan. 31, 1939 2,277,208 Chenoweth et a1. Mar. 24, 1942 2,284,043 Clausen May 26, 1942 2,318,828 Yerkovich May 11, 1943 2,340,658 Goldman Feb. 1, 1944 2,359,255 Smith Sept. 26, 1944
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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2691529A (en) * 1948-08-30 1954-10-12 Dictaphone Corp Phonograph stylus lifting cam and backspacing mechanism
US2858135A (en) * 1951-10-25 1958-10-28 Henry A Sherwood Sound recording and reproducing apparatus
US2930243A (en) * 1950-04-19 1960-03-29 Proctor Dictating Machine Corp Dictation machine
US3134599A (en) * 1959-09-25 1964-05-26 Dictaphone Corp Dictation apparatus
US3950784A (en) * 1973-08-06 1976-04-13 Nippon Data Recorder Co., Ltd. Apparatus for automatically adjusting the playback position of magnetic data recording device

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Publication number Priority date Publication date Assignee Title
US694784A (en) * 1901-07-12 1902-03-04 Daniel Ramsay Automatic drilling-machine.
US2145498A (en) * 1928-03-16 1939-01-31 Stromberg Carlson Telephone Phonograph
US2277208A (en) * 1935-12-07 1942-03-24 C W B Dev Co Dictating machine
US2284043A (en) * 1941-01-28 1942-05-26 Gray Mfg Co Marking mechanism for dictation machines
US2318828A (en) * 1940-11-23 1943-05-11 Dictaphone Corp Phonograph
US2340658A (en) * 1939-04-10 1944-02-01 Isidore H Goldman Sound recording apparatus
US2359255A (en) * 1941-11-21 1944-09-26 Seneca Falls Machine Co Control mechanism for machine tools

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US694784A (en) * 1901-07-12 1902-03-04 Daniel Ramsay Automatic drilling-machine.
US2145498A (en) * 1928-03-16 1939-01-31 Stromberg Carlson Telephone Phonograph
US2277208A (en) * 1935-12-07 1942-03-24 C W B Dev Co Dictating machine
US2340658A (en) * 1939-04-10 1944-02-01 Isidore H Goldman Sound recording apparatus
US2318828A (en) * 1940-11-23 1943-05-11 Dictaphone Corp Phonograph
US2284043A (en) * 1941-01-28 1942-05-26 Gray Mfg Co Marking mechanism for dictation machines
US2359255A (en) * 1941-11-21 1944-09-26 Seneca Falls Machine Co Control mechanism for machine tools

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2691529A (en) * 1948-08-30 1954-10-12 Dictaphone Corp Phonograph stylus lifting cam and backspacing mechanism
US2930243A (en) * 1950-04-19 1960-03-29 Proctor Dictating Machine Corp Dictation machine
US2858135A (en) * 1951-10-25 1958-10-28 Henry A Sherwood Sound recording and reproducing apparatus
US3134599A (en) * 1959-09-25 1964-05-26 Dictaphone Corp Dictation apparatus
US3950784A (en) * 1973-08-06 1976-04-13 Nippon Data Recorder Co., Ltd. Apparatus for automatically adjusting the playback position of magnetic data recording device

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