US2349018A - Tape driving system for magnetic sound recording machines and the like - Google Patents

Description

H. G. TASKER 2,349,018 TAPE DRIVING SYSTEM FOR MAGNETIC SOUND RECORDING I May 16, 1944.

MACHINES AND THE LIKE 3 Shgets-Sheet 1 Filed Oct. 24, 1940 In 0622 For fiom er 6'. Raw/ken 1 944. H, cs. TASKER 2,349,018

TAPE DRIVING SYSTEM FOR MAGNETIC SOUND RECORDING MACHINES AND THE LIKE E Filed on. 24, 1940 s Sheets-Sheet 2 May 16 y 6, 1944. H. G. TASKER 2,349,018 TAPE DRIVING SYSTEM FOR MAGNETIC SOUND RECORDING MACHINES AND THE LIKE Filed 0ct. 24, 1940 3 Sheets-Sheet 3 In I) all to):

Homer 6. fizsker:

Patented May 16, 1944 TAPE DRIVING SYSTEM FOR MAGNETIC SOUND RECORDING MACHINES AND THE LIKE Homer G. Tasker, Van Nuys, Calif., assignor to Herman S. Heller, West Los Angelcs, Calif.

Application October 24, 1940, Serial No. 362,701

4 Claims.

This invention relates generally to driving systems for magnetic sound recording machines and the like employing record tape. The invention is herein described principally as a drive system for a record tape of the magnetic type of sound recording and reproducing machine, though without necessary limitation thereto.

The record tape of magnetic sound recording machines is commonly fed from a supply .reel, is driven by a constantly driven drive pulley, and is taken up by a take-up reel. In prior sound recording machines, two or more shafts have been required for these reels and drive pulley, necessitating certain interconnecting gear. Over-rumning clutches have sometimes been provided, in such arrangement in the driving gear between the drive motor and the reels as to drive selectively the reel acting as take-up reel for the direction the tape is then being driven by the drive Pulley.

A general object of the present invention is the provision of a tape driving system of increased compactness, in which both reels as well as the constant speed drive pulley are mounted on a single shaft, so as to do away with all gearing for interconnection between a plurality of shafts.

A further object is the provision of an im= proved and more compact arrangement of the over-running clutches employed for the purpose of selectively driving the take-up reel.

In accordance with the invention in its present preferred form, the tape drive pulley is mounted tightly on the single drive shaft, adapted to be driven in either direction by a reversible drive motor. The two-reels are also mounted on this same drive shaft, and the over-running clutches are contained within the hubs of said reels, the arrangement being such that for one direction of rotation of the single drive shaft, one of the reels will be driven and the other will idle, and for the reverse directiontof rotation of the drive shaft, the second mentioned reel will be driven and the first mentioned reel will idle. Th tape is guided from one reel into the plane of the drive pulley, passes over the drive pulley and through the translating magnets while in said plane, and is then guided into the plane of and wound on the other reel. The arrangement is very simple and compact, and provides a tape drive system characterized by exceptional smoothness of action and uniformity of tape travel past the translating magnets.

The invention will be best understood from the following detailed description of a present illustrative embodiment thereof, reference for this purpose being had to the accompanyin: drawings, in which: 7

Fig. 1 is an elevation of a recording machine in accordance with the invention;

' Fig. 2 is a horizontal section taken on line 1-4 of Fig. 1;

Fig. 3 is a section taken in accordance with line 3-3 of Fig. 2;

Fig. 4 is a section taken on line 4-4 of Fig. 3; and

Fig. 5 is a section taken on line 5-5 of P18. 2,

Numeral Ill designates generally a supporting panel, typically, though not necessarily, arranged in a vertical plane. Mounted on the back of this panel 10 is a reversible electric drive motor H, on one end of which is mounted a right angle drive H from which projects a motor driven drive shaft it, the latter projecting through panel II] as illustrated. Shaft I3 is drivingl connected to a shaft II that carries a drivin pulley l5 and a pair of reels i6 and ii, the pulley being tightly mounted on shaft I4, and being located between the reels and panel ll, all as clearly illustrated in Fig. 2. In the specific i1- lustrative embodiment of the invention here shown, shaft M is hollow and receives the end portion of shaft 13, being provided with slots ll at its inner end receiving a. transverse pin 2! carried by shaft i3. Shaft H is thus positively clutched to shaft i3.

Shaft M has an enlarged rearward portion 22 on which is press fitted a flanged bushing 23 and awasher 24 which define an annular channel 25 that receives a complementary bearing ring 26, the latter being held within a retainer ring 21 secured to panel It as by screws El. Shaft it with bushing 23 and washer 24 thus turn freely within bearing member 26.

The hub 3d of the aforementioned tape driving pulley I5 is tightly mounted on shaft ll immediately adjacent shoulder 3| formed between shaft l4 and its enlarged rearward portion 2!. Immediately forwardly of pulley I! are the two reels I6 and H, which have driving engagement with the shaft through over-running clutches contained within their hubs, as presently to be described. Each of these reels embodies a pair of tubular hub members 40. and M, which together define an annular space 41 surrounding shaft I4, and which are formed with engaging peripheral annular flanges 43, to which are accured reel flanges N, the flanges 43 and 44 being secured to ether as by means of the socket and screw elements 45 and 46. The two flanges 43 space the reel flanges 44 properly for the tape T.

which is wound around the periphery of the flanges 43, as will readily be understood from an inspection of Fig. 2.

Enclosed and relatively rotatable in the annular space 42 defined by hub members 40 and 4| is a clutch disk 50 having a central bore 5| which receives shaft I4 with free rotative fit. Mounted in angularly disposed cavities or recesses 52 formed in disk 50 and opening inside bore 5| are rollers 54 which engage shaft I4 (see Fig. 1). The rollers 54 are yieldingly urged into engagement with shaft I4 by means of resilient elements such as felt pads 55 placed in recesses 52 in back of the rollers. The rollers are retained in position by means of a retainer plate 55' mounted in a countersink in the side of disk 50. The described elements form a simple and effective over-running or roller ratchet clutch. The over-running clutches for the two reels will be understood to be identical except that the angular direction of the clutch roller slots or recesses 52 for the two clutches will be understood to be in reversed aspect, right for left, so that rotation of shaft I4 in a left-handed direction as viewed in Fig. 1 causes rollers 54 of the clutch contained within the hub of reel II to engage the shaft, so as to drive reel I'I, while for right-handed rotation of shaft I4, the rollers 54 of the clutch contained within the hub of reel IE will drivingly engage the shaft so that reel I6 is then driven. Of course, reel I6 idles when reel I1 is being driven with left-handed rotation of the shaft, and reel I'I idles when reel I6 is being driven with right-handed rotation of the shaft.

The rotation of clutch disks50 is imparted to the reel through pairs of buttons or pads 60, preferably formed of some such material as fibre or Micarta, which are mounted in holes 5| extending through the disk and are pressed outwardly against the inside surfaces of hub members 40 and 4| by means of springs 62. There may be several such pairs of pads 60 spaced about the hub of the reel, as-will be understood. The spring-pressed pads 60 provide a yielding or slipping frictional or driving connection between the sides of the disk and the hub of the reel, so that the slippage made necessary'by the fact that the roll of tape on the reel is of greater diameter than the drive pulley I5, and hence must rotate more slowly than the drive pulley, may take place at this point.

A slight frictional drag is preferably applied to each reel, in order to prevent the reel from over-running while it is idling on its shaft, or in other words, while it is acting as the feed reel, and also to promote quick stoppin of both reels when the drive shaft stops. In the present illustrative embodiment of the invention, this frictional drag is provided by parts of or elements mounted on a pair of magazines I0 provided for the two reels. These magazines 10 each comprise circular side wall portions II and I2 having overlapping peripheral portions 13 and I4, respectively. The side walls II and I2 of each container have central openings I5 which receive tubular bosses I6 and I1 projecting from the two hub members 40 and 4|, and the side walls II and I2 have inwardly indented portions I8 immediately around apertures 15 adapted to bear against the sides of hub members 40 and 4|. Preferably, in order to increase the frictional effect, hub members 40 and 4| are faced with fibredisks I9. Additional friction means in the form of friction shoes I9, of fibre or the at their ends inwardly bent portions like, are preferably mounted on spring arms 40- secured to the walls I2 of the magazines, and are arranged to bear on the fibre-faced sides of the reel hubs, as clearly illustrated in Fig. 2. The pressure exerted by these shoes is adjustable by means of screws 81 passing through' container walls I2 and having screwthreaded engagement with the arms 80, in the arrangement clearly shown in Fig. 2. It will be evident that rotation of screws 8| will flex arms in such a way as to adjust the frictional pressure exerted by shoes I9 "against the hubs of the reels. These frictional effects, as stated hereinabove, apply a slight drag to the reels, and thus prevent them from over-running while acting as supply reels, as well as causing them to stop more or less abruptly when the drive shaft stops.

The outside bosses ll of the two reel hubs are preferably formed with slots such as 04, enabling the hubs to be engaged and turned by a suitable spanner wrench as an aid in removing the reels from shaft I4.

As here shown, the two reel containers II are mounted in face to face contact and are positioned against brackets secured to panel I0. Releasable clamp arms 9|, pivoted on brackets 90, as at 92, extend outwardly in contact with the peripheries of magazines I0, and have 93 engagmg over the magazines as clearly illustrated in Fig. 2. Extensions 94 from arm 9| are engaged by springs 95 mounted on brackets 90, which springs are arranged to yieldingly support the clamp arms in the clamping position of Fig. 2, but to permit outward movement of the clamp arms to clear the magazines when the latter are to be removed from the drive shaft, all as will be clear from an inspectionof Fig. 2.

In order to prevent rotation of the magazines I0, portions oi! the outside peripheral flange I4 of each magazine are severed and rolled outwardly, as indicated at I00, so as to receive between them opposite edges of one of the clamp arms (see Fig. 5).

Apertures I02 adapted to in the peripheral indicated in Fig. 1.

The two ends of tape T ma be anchored to the reel hubs in any suitable or conventional manner, though Fig. 1 shows one simple and convenient arrangement, in accordance with which the end of the tape is provided with an enlarged portion I03 adapted to be received transversely into a socket or drill hole I04 extending inwardly through the inner portion of a reel flange 44 and through hub flanges 43, an angular slot I05 connecting said hole I04 with the peripheral hub surface deflned by th outer edges of hub flanges 43.

In accordance with the particular tape threading arrangement here illustratively shown, the tape is wound right-handedly on outside reel I1 and left-handedly on inside reel I6. From outside reel I! the tape is threaded over angularly pass tape T are formed portions of the magazines, as

positioned pulleys H0 and III, which convey the tape to a plane to the rear of the two reels and in alinement with tape driving pulley I5. The tape then passes over the top side of tape driving pulley I5 (see Fig. 3), then passes in a substantially horizontal direction to and under a tensioning pulley H2, and from there passes upwardly to and around an idler pulley III, the latter being mounted near the top of panel I0. From idler pulley II3 the tape passes straight downwardly to and around a similar idler pulley III immediately under pulley II3 but positioned near the bottom of panel I0. The tape next travels upwardly in an angular direction to and over a tensioning pulley II5, located immediately below tensioning pulley H2, and from there travels back in a substantially horizontal direction to pass over the lower side of drive pulley I5. The tape next passes to and around an angularly positioned idler pulley II6, which takes it to the plane of inside reel I5, the tape then being wound onto reel I6 as indicated inFig. 2.

The above mentioned idler pulley H3 is furnished with a pair of spring urged retaining rolls I20 which bear on the tapepassing over the pulley H3, and the pulley H4 is equipped with a single spring urged retaining roller I2I which engages the tape as it passes over pulley III.

The tensioning rollers H2 and H5 are mounted on a stud I26 screwed-into panel I0, the arms H4 and I25 being received between a shoulder I2? presented by a hexagonal flange I28 formed integrally with stud I26, and the large flat head H23 of a screw I30 screwed into said stud, friction washers I3I separating the two arms from one another and separating the arms from flange H3 and head I29, all as will be clear from inspection of Fig. 4. The two arms I24 and I25 are interconnected by tension spring I35 which serves to urge the two rollers H2 and H5 into tensioning engagement with the tape, while a tension spring I36 connected between upper arm H4 and an anchor pin I31 set into panel I counteracts the effect of gravity on the arms and rollers.

A pair of retaining rollers I40 are mounted on the arms of a yoke shaped plate I and are adapted to be supported by plate MI in a position to hold the tape in driving engagement with pulley I5. Plate I4I has an extension I42 surrounded by a compression spring I43 and having pivotally mounted on its rearward end a cam having a projecting pin I46 by which it may be conveniently manipulated. The periphery of cam I45 is adapted to be brought to bear against a stationary bracket I50 secured to panel I0, said bracket being provided with an aperture I5I that slidably passes the extension I42 of yoke plate I. One end of spring I43 bears against one side of this bracket I50 and the other .end of said spring bears against the plate I, which has an offset at I54 and outwardly extending ears I55 to receive the pressure of said spring. It will be understood that rotation of cam I45 will draw yoke plate HI and the retaining rollers 40 rearwardly and out of engagement with the tape on drive pulley I5, but that when cam I45 is in the position of Fig. 3, yoke plate MI is being urged in the direction of pulley I5 by the pressure of spring I43, and that retaining rollers I40 are therefore in pressural engagement with the tape on the periphery of pulley I5.

The vertical stretch of tape between the two idler pulleys I I3 and H4 passes between the two halves of a translating magnet head R, which may be of any suitable or usual construction, and need not be detailed herein.

The operation of the tape driving system of my invention is as follows: Rotation of drive shaft I4 in a right-handed direction causes the over-running clutch contained within the hub of inside reel I6 to grip the shaft, so that clutch disk 50 turns right-handedly with the shaft, and, through spring urged pads '60, applies a frictional drive tendency in a right-handed direction to the hub of reel I6. At the same time. r e 75 drive shaft,

I I will simply idle on the shaft. The tape then travels from reel I! over the top side of drive pulley I5, through the translating magnet head, over the underside of drive pulley I5, and finally onto inside reel I6 which is being driven as above described. The diameter of the roll of tape on reel I8 being always greater than the diameter of drive pulley I5, the reel tends to take up the tape faster than it arrives from the drive pulley. Accordingly, slippage takes place between the positively driven clutch disk'50 and the hub of the reel at the points where the spring pressed friction pads 60 drivingly engage the hub. There is thus an over-drive tendency on the reels, but the reels are held back to a speed determined by the rate of arrival of the tape. The idling reel I1 is at this time being prevented from over-running by the frictional effect of the indented portions 11 of the magazine on the sides of the hub, and also by the frictional pressure of shoe I9 on the hub. These frictional effects are preferably made sufficient that th idling reels will stop more or less abruptly when drive shaft I4 is stopped. For the reverse direction of rotation of shaft I4, operations are similar, except that the tape on this instance travels from inside reel I5, then idling and serving as supply reel, to outside reel H, which is then driven and serves as take-up reel. The two movably mounted tape tensioning pulleys H2 and H5 act constantly to maintain the tape properly taut between the drive pulley I5 and the pulleys H3 and H4 at the two ends of translating magnet units R.

My preferred form of drive embodies the feature of a tape driving pulley and two reels, each containing an over-running clutch, all mounted on a single drive shaft, the pulley being tightly mounted on the shaft, and the reels being alternately clutched to the shaft as the shaft turns in one direction and then the other. However, certain features of my invention are not limited to a concentric arrangement of reels and drive pulleys. For instance, it is not indispensable to the invention, even though highly desirable, that the drive pulley I5 be mounted on the same shaft or axis with the reels. Thus even without the desirable feature of concentricity between reelsand drive pulleys, great advantage, compactness and simplicity results from the incorporation of the over-running clutches inside the hubs of the two reels. Moreover, it is not indispensable to the invention in the aspect of the provision of over-running clutches inside the reel hubs that the two reels be mounted in concentric relation on a single shaft, and certain of my claims are accordingly made to the provision of an overrunning clutch within the hub of a reel, irrespective of the relative arrangements of the other reel or of the remainder of the tape driving system.

I have now shown for illustrative purposes one present specific form of my invention; it will be understood, however, that this is for illustrative purposes only, and that various changes in design, structure and arrangement may be made without departing from the spirit and scope of my invention or of the appended claims.

I claim:

1. In a record tape driving means for a sound recording and/or reproducing machine, the combination of a drive shaft, a smooth periphery tape engaging tape drive pulley on said drive shaft, a pair of reels relatively rotatable on said means for guiding and supporting the tape between said reels to pass in driving contact with two points of said pulley, means for tensing the tape between said points of contact and over-running clutches for said reels adapted and arranged to clutch the reels to the shaft alternately as the drive shaft is driven in reverse directions.

2. In a record tape driving means for a sound recording and/or reproducing machine, the combination of a drive shaft, a tape engaging tape drive pulley on said drive shaft, a pair of reels relatively rotatable on said drive shaft, means for guiding the tape to pass in peripheral driving contact with said pulley between said reels, each of said reels embodying a hollow reel hub and a pair of reel flanges for a record tape, over-running clutch disks surrounding the shaft within the hollows of said reels, ratchet rollers carried by said disks and adapted to clutch said disks to the shaft with opposite directions of retation of the shaft, and friction elements projecting from the sides of the disks into frictional driving engagement with the hubs.

3. In a record tape driving means for a sound recording and/or reproducing machine, the combination of a drive shaft, a tape engaging tape drive pulley on said drive shaft, a pair of reels relatively rotatable on said drive shaft, means for guiding the tape to pass in peripheral driving contact with said pulley between said reels. each of said reels embodying a hollow reel hub and a pair of reel flanges for a record tape, overrunning clutch disks surrounding the shaft within the hollows of said reels, ratchet rollers carried by said disks and adapted to clutch said disks to the shaft with opposite directions of rotation of the shaft, and spring pressed friction pads on the sides of the disks frictionally drivingly engaging the hubs.

4. In a record tapedriving means for a sound recording and/or reproducing machine, the combination of a drive shaft, a smooth periphery tape engaging tape drive pulley on said drive shaft, a pair of reels relatively rotatable on said drive shaft, over-running clutches for said reels adapted and arranged to clutch the reels to the shaft alternately as the drive shaft is driven in reverse directions, tape guide means for guiding the tape between the two reels and two spaced arcs of peripheral contact with the tape drive pulley and means for tensing the tape between said ,arcs of contact.

HOMER. G. TASKER.

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