US2321812A

US2321812A - Tape driving system for magnetic sound recording machines and the like

Info

Publication number: US2321812A
Application number: US366232A
Authority: US
Inventors: Herman S Heller; Donald E Ross; Forrest J Lilly
Original assignee: Heller
Current assignee: Heller
Priority date: 1940-11-19
Filing date: 1940-11-19
Publication date: 1943-06-15
Anticipated expiration: 1960-06-15

Description

C SOUND 5 Sheets-Sheet 1 ller-m an S Heller. lza/d 0,553

June 15, 1943- H. s. HELLER Erm.

TAPE DRIVING SYSTEM FOR MAGNETI RECORDING MACHINES AND THE LIKE Filed Nov. 19, 1940 June 15,1943. H. S. HELLER I|- r AL TAPE DRIVING SYSTEM FOR MAGNETIC souND y RECQRDING MACHINES AND THE LIKE Filed Nov. 19, 1940 5 Sheets-Sheet 2 In Hanford. Herman 51 Heller: ofz ala i f? 0,55'.

June 15, 1943. H. s. HELLl-:R ETAL TAPE DRIVING SYSTEM FOR MAGNETIC SOUND RECORDING MACHINES AND THE LIKE Filed Nov. 19, 1940 5 Sheets-Sheet 3.

June 15, 1943. H. s. HELLER E-rAl.

TAPE DRIVING SYSTEM FOR MAGNETIC SOUND RECORDING MACHINES AND THE LIKE Filed Nov. 19, 1940 5 Sheets-Sheet 4 /lz 11e/v a las'. lier/wall 5. Heller. ofzald 0525. lbf/'19.55 I Z Z'Zl'y.

H. s. HELLER l-:rAL 2,321,812 TAPE DRIVING SYSTEM FOR MAGNETIC SOUND RECORDING MACHINES AND THE LIKE Filed Nov. 19, 1940 A June 15., 1943.

5 Sheets-Sheet 5 Bmew Fatented June 15, 1943 TAPE DRIVING SYSTEM FOR MAGNETIC SOUND RECORDING MACHINES AND THE LIKE llerman S. Heller, West Los Angeles, Donald E. Ross, Eagle Rock, and Forrest J. Lilly, Los Angeles, Calif.; said Ross and said Lilly assignors to said Heller Application November 19, 1940, Serial No. 366,232

Claims.

v,past to drive the tape at a point between the two reels by means of a constantly driven drive pulley, the take-up reel ybeing slightly overdriven, with frictional slip, as by means of a slipping belt, to take up the tape as fast as it is supplied from the drive pulley. Certain problems, however, are introduced when it is desired to provide for driving the tape at constant speed in either direction at will, and while these have been solved in various ways in the past, further simplification is desirable.

The primary object of the present invention is therefore the provision of an improved and simplified driving system for the tape of magnetic sound recording machines and the like.

In accordance with the present invention, the usual constant speed tape driving pulley is eliminated and the tape driven by the take-up reel. Since, however, a usual constantly driven takeup reel would move the hn faster and faster as it reeled the lm up (owing to the gradually increasing circumference of the roll of tape on the take-up reel), the present invention provides a means for compensating the speed of the take-up reel in accordance with the quantity of the tape reeled thereon.

In accordance with the present preferred form of the invention, the required speed compensation is introduced by varying the speed of the electric drive motor. Preferably, there is used for this purpose a drive motor equipped with a governor capable of being mechanically adjusted to vary motor speed while the motor is running, this governor being constantly automatically adjusted in accordance with the varying quantity of the tape on one of the reels.

In a preferred embodiment of the invention, one of the reels is directly and positively coupled to the drive motor, and means are provided for automatically regulating the drive motor governor to vary the speed of the motor inversely with the diameter of the tape on that reel. When that reel is serving as the take-up reel, it accordingly gradually decreases in speed as the tape roll wound on it increases in diameter, so as to preserve a constant tape speed. Provisions are made whereby the other reel, then serving as the supply reel, simply idles during this time. For the reverse direction of tape drive, the rst mentioned reel becomes the supply reel. This reel remains directly coupled to the drive motor, and the speed of the drive motor is again regulated. through its governor, to vary the speed of drive of said reel inversely with the diameter of the roll of tape on the reel. Thus, for the reverse direction of drive of the tape, the reel then serving as the supply reel is positively driven, at

`gradually increasing speed. At the same time.

the reel then serving as the take-up reel is overdriven, through a friction slip clutch, so as to take up the tape as fast as it is supplied from the supply reel. Thus for both directions of tape travel, the quantity of tape on the one reel. which may be called the control reel, governs the speed of the drive motor. For one direction of travel, the tape is taken up by this control reel, while the other idles; for the other direction of travel, the tape is supplied from the control reel, and the other reel is over-driven, with slip, and

takes up the tape at whatever speed it is supplied from the control reel. And for both directions of travel, the control reel is driven at a speed inversely proportional to the circumference of the roll of tape thereon, so that the linear speed of the tape between the two reels is substantially constant.

Various additional objects, laccomplishments and features of advantage will appear and be described in the course of the following detailed description of a present preferred embodiment of the invention, reference for this purpose being directed to the accompanying drawings, in which:

Fig. 1 is a vertical longitudinal section through a magnetic sound recording machine embodying thex present invention, Fig. l being taken in accoi-dance with line l-i of Fig. 2;

Fig. 2 is a section taken as indicated by line 2-2 of Fig. 1:

Fig. 3 is a view taken as indicated by line 3-3 of Fig. l, the reel-carrying unit at the top of the ma hine being removed;

Fig. 4 is an enlarged view similar to a portion of Fig. l, but with the reels and the drive gear for the reels appearing in section;

5 is a detail section taken on line 5-5 of Fig. 6 is a transverse section taken on line of Fig. 4; v

Fig. 7 is a transverse section taken on line 1-1 of Fig. 4;

. Fig. 8 is a transverse section taken on line 6 2 oi' Fig. 4;

Fig. 9 is a detail section taken on line'S-Q of Fig. 3;

Fig. 10 is a view taken as indicated by line III- I of Fig. 2;

Fig. 11 is a detail section on line II-II of Fig. 4;

Fig. 12 is a detail section on line I2--I2 of Fig. 2, the cover plate being added;

Fig. 13 is a diagrammatic view of the motor controlling governor; and

Fig. 14 is a diagram of a somewhat simplified but illustrative electrical circuiting arrangement for the machine.

The embodiment of our invention here chosen for illustrative purposes is of a type in which a multiplicity of separate recordings may be made side by side on a single record tape, the several successive recordings being made with the tape travelling first in one direction and then in the other. Such a magnetic sound recording machine is disclosed in United States Letters Patent No. 2,213,631, to Herman S. Heller and Leo G. Butler, dated September 3, 1940, to which reference is directed, and it will be understood that the present invention is concerned not with methods of producing multiple recordings on a single tape, but with means for driving the tape at uniform speed, in either one direction or both directions,

whether or not multiple recording is incorporated.

Of course, unless successive recordings are to be made with the tape travelling first in one direction and then the other, the provision of uniform tape speed in both directions of travel may not be essential. The present invention is therefore to be understood as providing means for driving the tape at uniform speed in one direction, or in both directions, depending upon requirements.

The illustrated embodiment of the presentinvention discloses an arrangement in whichv the reels, translating magnets and tape guides are mounted on a unit which is quickly separable or detachable from the main housing of themachine containing the drive motor, drive gearing, together lwith necessary amplifier, relays and switches not here illustrated. This feature. which is desirable, though in no way essential to the present invention, is disclosed and claimed in copending application of Herman S'. Heller, entitled Tape type recording and reproducing machine, led October 23, 1940, Ser. No. 362,349. The advantage of the arrangement is that it permits interchange of record tapes simply by changing the detachable unit, thus obviating the difficulties and time consumption incident to changing tapes.

by the usual methods.

Thus, as shown best in Fig. l, the illustrative machine comprises a main housing I5, having a top plate IG/on which the driving gear is mounted, and a detachable unit I1 mounted on top of housing I and resting down on top frame plate I6 of the latter. Detachable unit I1 has a bottom or frame plate I8, preferably provided with apertures I9 which go onto positioning pins 20 extending upwardly from top plate I6 vof housing I5, and has a removable cover 2l. Preferably, a quickly releasable catch means is provided for detach-- ably securing unit I1 down to main housing I5.

Such catch means may typically comprise a strap 24 slidable across the top of the base plate Il f of unit I1 and provided with slots 25 adapted to receive catch hooks 26 extending upwardly from top plate I6 of housing I5. Strap 24 is here shown as guided by means of screws 21 mounted in plate I4 and received within longitudinal guide slots 26 in the strap. A spring 2l urges strap 24 to locking position, while 'an upturned end portion Il of the strap is adapted to be engaged by a plunger 3| mounted in cover 2i (see Fig. 12), depression of plunger 3|v moving strap 24 to disengage from hooks 26.

While not an essential, a feature of great ad- 4 vantage in the illustrative embodiment of the invention is the provision of a co-axial relationship of the two reelsjand of the driving members for said reels. This co-axial relationship yields substantial savings in space, and enables thev unit to be much more compact than would otherwise be the case. We therefore illustrate and describe one specific embodiment of the invention in which the two reels and the driving gear are embodied in a co-axial design.

'The preferred driving gear has a gear housing 4I, mounted on the underside of top plate I6 of housing I5, and here shown as comprising an upper housing block 42, a lower housing block 42,

lalud an intervening plate 44,

members

42, 43 and 44 being secured inA assembly by screws 4Ia, and being secured to the underside of plate I6 as by screws I6a, as shown in Figs. 3, 4, 6 and 8. The electric drive motory45 is secured Ato Athe bottom of block 43 as by means of screws 46 passing downwardly through block 43 and engaging the motor housing. Motor 45 is mounted with its drive shaft 41 in a vertical position, as indicated in Fig. 8.

In the'preferred and illustrative form of the invention, electric drive motor 45 is of a type equipped with a governor such as may be regulated to vary the speed of the motor while the motor is running. A suitable motor equipped with such a governor is manufactured .by Bodine L meshing with a worm wheel 5I on a horizontal shaft 52 journalved in housing block 43 (see Fig. 8), and a spiral gear 53l on shaft 52 meshes with a spiral gear 54 that surrounds vertical shaft 55 which extends upwardly into housing .block 42, and has-'at its lupper end a disk 56 forming the drive element of an overrunning clutch generally designated at 56a. A bushing 55a set into the bottom of housing block 43 serves asA a'journal for the lower end of shaft 55, and as a thrust bearing'for spiral gear 54. A washer 51 surrounds shaft immediately above spiral gear 54, and is keyed or drivingly connected at the bottom with the topof gear 54 as indicated at 58. The upper side of washer 51 is keyed or drivingly connected, as at 59, with the lower end of a gear sleeve surrounding shaft 55 below clutch disk 56, sleeve 60 being drivingly connected to shaft 55 as by means of transverse connecting pin 6I. Sleeve 60 has at the top a spur gear 62, and this gear as well as clutch disk 56 are thus positively driven from motor shaft 41.

Meshing with gear 62 are spur gears 65 (see Figs. 4 and 7) mounted on studs 65a set into housing plate 44. spur gears 65 meshing in turn wardiy from the wall 61a at the top of sleeve 61 is a tubular boss 68 which is journaled in a bushing 69 that is mounted in the top of housing block 42 and that extends through an aperture in frame plate I6. Boss 68 has clutch jaws 12 above plate I6, which interengage with clutch teeth 13 formed at the lower end of a tubular boss 14 extending downwardly from reel supporting disk 15. Boss 14 and the portion of boss 68 that projects above plate I6 are rotatable within a bushing 16, which has an intermediate outwardly extending annular flange 11. This flange 11 is received between two

annular plates

18 and 19 which surround and support bushing 16, and which are fastened down to plate |8 as by means of screws 80. Disk has an upwardly projecting pin 8|, which is adapted to engage in the socket 82 formed in the underside of the central hub 83 of a lower tape reel 84. Hub 83 has a central bore 85 which receives a tubular boss 85 extending upwardly from reel supporting disk 15.

Reel 84 comprises, in addition to the aforementioned hub 83, a pair of suitably spaced side flanges 90, the tape T being rolled onto hub 83 between flanges 90 as indicated.

The aforementioned over-running clutch 56a is of a usual roller ratchet type, the disk 56 at the top of shaft 55 having angular recesses 90 in its periphery receiving spring-pressed rollers 9| adapted to engage the inner periphery of an inverted cup shaped clutch member 92 (Figs. 4 and 6). This member 92 vis centrally apertured, as indicated at 93, so as to pass a stud 94 which is screwed upwardly into a shaft 95 that is rotatably received inside tubular member 68. Formed at the lower end of shaft 95 is a friction disk 96, the upper side of which has an annular upwardly facing surface 91 which has bearing against the downwardly facing surface 98 of the wall 61a at the top of sleeve 61. A friction washer |00, formed of felt or the like, is placed between the opposed annular facesformed on disk 96 and on the top of cup shaped clutch member 92, as shown in Fig. 4. A spacer ring |0| seated in disk 56 serves to space member 92 slightly above the upper side of clutch disk 56. The head of stud 94 is received in a, cavity |02 sunk in the center of disk 56 (see Fig. 4), and confined between this head and a Washer |03 splined on the shank portion of the stud is a compression spring |04. Washer |03 seats against the underside of cup 92, and spring |04 acts to press the member 92 into frictional engagement with friction washer |00. Spring |04 exerts sufficient force on member 92 to permit driving torque to be transmitted from the latter through friction washer |00 to disk 96; however, under certain circumstances later to be explained, slippage may take place at this location.

The upper end of shaft 95 has, above plate |6, a reduced, upwardly extending centering pin I I0, and also clutch elements formed at opposite sides of the base of the pin. A reel carrying shaft I|2 is rotatively received within tubular boss 14, being journaled in a bearing bushing II3 placed inside the latter, and has a socket II4 adapted to receive centering pin |I0, and also clutch elements ||5 adapted to interengage with clutch elements on shaft 95 (see Figs. 4 and 5). Shaft ||2 is thus drivingly interconnected with shaft 95. The upper end of shaft ||2 is formed with an enlarged reel-carrying head ||6, having an annular downwardly facing shoulder |I1 which bears on bearing washer IIB resting on the upper end of tubular boss 86. Upper reel may be substantially the same as lower reel 84, its hub I2| being centrally bored to receive head ||6, as indicated. It has, however, a means for drlvingly interconnecting it with head IIB. As here shown, this means comprises a locking pin |24 mounted radially in hub |2I and adapted to be projected by spring |25 into locking engagement with longitudinal key-way |26 in head |I6.

.A friction washer |30, typically formed of felt, ls placed between the hubs 83 and I2|, respectively, of the two reels, the upper face of hub 88 of the lower reel being preferably provided with an annular groove |3| within which said washer ls seated. This friction washer |30 serves a purpose which will, be explained hereinafter.

It will be understood that when the unit I1 is mounted on the unit |5, the driving element 14 for lower reel 84 is clutched to tubular member 68 projecting upwardly through top plate I6 of unit I5, and the driving element ||2 for top reel |20 is similarly clutched to drive shaft 95, also projecting upwardly through top plate I6 of unit I5. Cover 2| of unit I1 being removed, lower .reel 84 is slipped on over tubular member 86 and driving pin 8| engaged with socket 82, friction washer |30 is then placed in position. and then upper reel |20 is slipped on over head ||6 and driving pin |24 engaged with key-Way |28. Thus separate transmission means, in the form of concentric, relatively rotatable shaft and sleeve members, are provided between the motor driven shaft 55 and the two reels, these transmission means having disengageable connections which are in driving engagement when the unit I1 is mounted on main housing I5.

Inspection of Fig. 2 will reveal that tape T is wound on both reels in the same directibn. In the particular arrangement here illustrated, the tape is taken from lower reel 84 around and between a pair of tape tensioning guide pulleys and |4| to a guide element |42 at one end of a translating magnet unit |43. From the other end of magnet unit |43 the tape passes around a similar guide element |44, then travels around and between a pair of tape tensioning guide pulleys |45 and |46, from where it goes on to upper reel |20. 'I'he pairs of guide pulleys |40, |4| and |45, |46 are mounted on supports |41 which are pivotally mounted on the bottom plate |8 of unit I1 on pivot axes located between the pulleys. Coil springs |48 surrounding the pivots for the supports |41 exert a torque in a direction to move the pulleys to tension the tape slightly.

Each magnet |51 may include a wound magnetic tudinally of the tape for. each recording lane, one for recording and reproducing purposes and one for polarizing or record-obliterating purposes, and the tips of the pole pieces of these two magnets may contact the tape only within the limits of the lane of the tape on which they are to operate. Such a system of multiple lane recording is disclosed and claimed in United Btates Letters Patent No. 2,213,631, to Herman S. Heller and Leo G. Butler, and for a more complete understanding of such a system, reference is directed to said patent, it being sufficient to point out herein that the translating magnet unit |40 is so designed that recordings may be made on the tape with the tape moving in either direction.

. erted thereby through arm ernor housing |04, being pivotally supported on a pin' |94 mounted on housing lugs |06. Screwthreadedly mounted in the center of arm |02 is a governor controlling stud |00, which bears against the outerv end of a plunger |01 slldable in a guide |98, and which in turn bears against the end of a governor control arm 20| at a point located in line with the axis of rotation of the motor and governor. It may again be mentioned that the governor here shown for illustrative purposes is of a type known in the art, and a detailed description thereof, will not be necessary except insofar as to enable the present invention to be understood. A simple diagram i see Fig. 13) will suilice to illustrate the operation of this govemor. Governor arm 20| is one arm of a lever 201 pivoted at 200 on a plate or beam 2|0, the other arm of the lever comprising a centrifugal weight 2| I. The disposition of the parts is such that as the governor rotates with motor shaft 41, weight 2|I tends to move in the direction o1' the arrow ln Fig. 13. Beam 2|0 is mounted by means of a relatively stiff spring arm 2|2 on posts such as 2|! extending from insulation disk 2|4, set on posts 2|3 being electrically connected with collector ring 2 I 6 mounted on the back of disk 2|4. When the governor and motor are in rotation, weight 2li tends to move in the direction of the arrow in Fig. 13, as said above. and this causes the `weighted lever to tend to pivot on its axis at 208; such pivotal movement is prevented, however, by the end of plunger |91 in engagement with arm 20|. 'I'he result of centrifugal forces acting on weight 2| I accordingly is to move beam 2|0, on which the weighted lever is mounted, toward disk 2|4, spring arm 2| 2 yieldingiy opposing such action. Beam 2|0 carries an electrical contact 2 I6, which normally makes with y a contact 2|1 on a conductive support` 2|0 mounted on insulation disk 2|4 by means of post 2|8a, and electrically connected via port 2I0a with inner collector ring 2|9 on the back of disk 2|4, as indicated. When beam 2|0 moves toward disk 2| 4, under the influence of the centrifugal weight 2|I, contacts 2|6 and 2|1 separate, and break the electrical circuit between the two collector rings. The motor-,has brushes 220 and 22| bearing on collector rings 2|6 and 2|9, and such brushes are included in a circuit that energizes the motor as will later be explained.

A spring arm 222 extending from the springmounted end of beam 2|0 engages arm 201 on the side opposite plunger |91.

The speed of rotation at which governor weight 2I| will generate sufilcient centrifugal force to move beam 2|0 backwardly against spring arm 2|2 so as to break the electrical energizing circuit of the motor, depends upon the position of plunger |91. For example, if plunger |91 is so positioned that, at zero speed, no pressure is ex- 20| against spring arm 222, then the centrifugal force generated by weight 2|| will not become suillcient to deflect beam 2I0 against the pressure of spring arm 222 until a certain maximum speed of revolution is reached. But now if plunger |91 is advanced against arm 20| soY as to deflect spring arm 222 somewhat, then a proportionate part of the supporting power of spring arm 2|2 is counteracted. and the centrifugal force generated by weight 2| I at a lesser speed will be suilicient to deflect beam 2|0 against the resultant spring pressure then opposing deflection. .In this way, the speed of rotation at which beam 2|0 will deflect against supporting spring arm 2 I2 and there/by open contacts 2|6, 2|1, depends upon the axial position of plunger |91, so that by moving plunger |91 by means of stud |99, its carrying arm |92 and li-nk |9|, the speed at which the motor cuts out, or has its speed reduced, may be nicely regulated.

Fig. 14 shows a simplified but illustrative wiring circuit for drive motor 45. This motor is here shown as a series wound type, with provisions as indicated at 233 for reversing the field to reverse the direction of motor rotation. Included in one of the current supply leads 280 are the two governor brushes, 220 and 22| mentioned in connection with Fig. i3, these brushes being diagrammatically indicated in Fig. 14 as connected to governor contacts 2|6 and 2|1, respectively. Preferably, and as here shown,

openingvof contacts

216, 2|1 does not entirely open the motor circuit, but simply cuts a resistance in series with the line, so that the impressed voltage is decreased. This has the effect of reducing the motor speed. Accordingly, a resistor 235 and a condenser 236 are shunted across brushes 220 and 22|. When the speed of rotation of the motor and governor is sufficient to cause contacts 2|6 and 2|1 to become separated, the current supply to the motor is forced to flow through resistor 235, which materially reduces the voltage across the motor and therefore reduces motor speed. Thus each time the motor exceeds the speed for which the governor is set, the contacts 2|6 and 2|1 open, and the motor speed thereupon falls.

And when this occurs, contacts 2|6 and 2|1 again close. causing the motor speed to pick up. The

result 1s that the contacts 2|6, 2|1 are more or less constantly opening and closing, and motor speed is held very constant at a speed determined y by the setting of the governor. In accordance with the present invention, this governor setting is continuously varied, in such a way that the motor speed is continually varied, but the tape speed is maintained substantially constant.

The operation of the tape driving system of the present invention is as follows: Assume first that the tape is to be driven from top reel |20 to bottom reel 84, the tape travelling as indicated by the arrows in Fig. 2. Motor 45 will at such time be driven in such direction as to cause shaft 55 to rotate in a right-handed direction. Inspection of Fig. 6 will reveal that the over-running clutch at the top of shaft 55 will run free for this direction of rotation, and torque will not be transmitted to upper reel |20, which simply idles at this time. Lower reel 64 is, however, being driven from shaft 55 through spur gear 62, idler gears 65, internal gear 66, sleeve member 61 and the reel supporting member 15 positively clutched to the latter. The friction washer between the two reels exerts a frictional drag on idling upper reel |20 to prevent. it from over-running.

At times when the roll of tape on the reel |20 (then acting as supply reel) is larger than the roll of tape on reel 84 (then acting as take-up reel), the reel |20, reel carrying shaft ||2 and shaft 85 will of course rotate faster than reel 84, tubular member 14, and sleeve member 61. If shaft 55and over-running clutch disk 56 turned at the same rate as sleeve 61, power would then be transmitted from shaft 95 through the rollers of the over-running clutch to drive disk 56 and shaft 55. This condition is avoided by gearing sleeve 61 to turn substantially faster at all times than clutch disk 56, in the present instance, in a ratio of approximately 3 to l. With this provision, disk 56 will always turn faster than shaft 96, and clutch member!! will never catch up with and tend to drive clutch disk 66.

The speed'of motor 45 is under the control of the diameter of the roll of tape on lower reel 84. As the roll of tape on reel 84 (then acting as the take-up reel) grows larger and larger, the crank arm |8| carrying roller |90 bearing on the tape on said reel swings gradually outwardly, turning interconnected shafts |62 and III, and therefore spiral gear |19, in a leithanded direction. This rotation of gear |19 operates through studs |95 to swing lever |80 in a direction to elevate link |9| and pivoted arm |92. Stud |96 carried by arm |92 correspondingly elevates plunger |91, which depresses governor control arm 20| in an upward direction, causing the motor to gradually decrease its speed. Thus as the roll of tape on lower reel 84 grows larger and larger (which with constant speed of drive of the reel would mean greater and greater linear tape speed), the governor of the motor is regulated to give slower-and slower motor speed, with the result that the linear speed of the tape `is maintained substantially constant throughout the movement of the tape from the upper to the lower reel.

Operation for the reverse direction of tape drive, viz., from lower reel to upper reel, is as fcllows: Motor drives shaft 55 at such time in a left-handed direction, which causes clutch rcllers 9| to drive member 92. Member 92 drives disk 96 through friction washer |00, causing rotation of shaft I I2 clutched to shaft 95 and therefore rotation of upper reel |20 mounted on the head ||6 of shait ||2. Lower reel 84 is positively driven at such time through the same driving interconnections as for the first described direction of the tape, but of course in the reverse direction of rotation. The speed of drive of m0- tor 45 is again under the control of the diameter of the roll of tape on lower reel 84, roller arm |51 controlling the governor of the motor through the described interconnections to gradually increase tape speed as the diameter of the tape on lower reel 84 grows smaller and smaller. Proper take-up of the tape by upper reel |20 is accomplished by reason of the fact that the upper reel is over-driven, that is, driven at a speed somewhat above that permitted by the speed of the tape as fed from positively driven lower reel 84. In the present illustrative embodiment, this is accomplished by the drive ratios provided between shaft and each of the two reels. Thus as previously described, member 92 driven through the roller ratchet clutch turns at a ratio of one to one with shaft 55, whereas member 61 turns at a ratio of, for instance, l to 3 with shaft 55. It will be evident, therefore, that upper reel |20 is over-driven,- or driven at a speed faster than will be permitted by the speed of the tape as supplied from low'er reel 84. The result is that slippage takes place between friction members 92 and 96, so that, reel |20 actually turns at just the speed permitted by the rate of arrival of the tape from lower reel V84, the amount of the over-drive tendency on upper rcel |20 being sufficient to assure proper tensioning and proper take-up of the tape.

The linear speed of the tape between upper and lower reels is thus'made substantially constant, regardless of the direction of drive, by regulation of the motor speed under the control of the position of the tape on the reels. In the embodiment chosen for illustrative purposes, the speed of the motor is controlled always by they diameter of the tape on the lower reel, whether the lower reci is functioning as take-up reel -or supply reel. When the upper reel functions as supply reel. it simply idles, with friction hold back;

when it functions as taire-upv reel, it is overdrivon. with slippage, so as to take up the tape as fast as supplied by the lower reel.

We have now shown and described one present illustrative form which the invention may assume in practico; it is to 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 the invention or of the appended claims.

We claim: n

1. In a drive system for a sound record tape, the combination of two reels, a record tape extending between and wound on said reels, a reversible drive motor positively drivingly connected to one of said reels in a manner to drive said rcel in either direction without frictional slip, friction drive means for over-driving the other of said reels from ysaid motor when the tape is travelling in the direction from said one reel to said other reel, said friction drive means slipping suic'iently that said other reel travels at a speed determined by the rate of arrival of the tape from said one reel, and automatic means for regulating@ the speed of said motor inversely with the quantity of tape reeled on said one reel.

2. In a drive system for a sound record tape, the combination of two reels, a record tape extending between and wound on said reels, a reversible drive motor, positive non-slip driving gear between said motor and one of said reels, driving gear between said motor and the other of said reels including an over-running clutch so arranged as to cause said other reel to be driven only when acting as a take-up reel, said last mentioned driving gear tending to over-drive said other reel, a slip driving connection in said last mentioned driving gear, and automatic means for regulating the speed of said motor inversely with the quantity of tape reeled on said one reel.

3. In a drive system for a sound record tape, the combination of two reels, a record tape extending between and wound on said reels, a drive motor, a rotatable shaft adapted to be driven in either direction by said motor, positive non-slip driving gear between said shaft and one of said reels, driving gear between said shaft and the other of said reels, an over-running clutch inthe last mentioned driving gear so arranged as to' cause said other reel to be driven only when acting as a take-up reel, said last mentioned driving gear being adapted to exert an over-drive tendency on said other reel when acting as a take-up reel, a frictional connection permitting slippage between said shaft and said other reel whereby said other reel will travel at the speed permitted by the ratel of arrival of the tape from said one reel, and automatic means for regulating the speed of said motor inversely with the quantity of tape reeled on said one reel.

4. In a drive system for a sound record tape, the combination of two reels, a record tape extending between and wound on said reels, a drive motor, a rotatable shaft adapted to be driven in either direction by said motor, positive non-slip driving gear between said shaft and one of said reels, driving gear between said shaft and the other of said reels, an over-running clutch in the last mentioned driving gear so arranged as to cause said other reel to be driven only when vacting as a take-up reel, said last mentioned driving gear being adapted to exert an over-drive tendency on said other reel when acting as a take-up reel.

5. In a drive system for a sound record tape the combination of a reversible drive motor, two co-axial relatively rotatable transmission means driven by said motor, one of said transmission means being adapted to transmit a positive drive in either direction of rotation. an over-running clutch and a slip driving connection in the other of said transmission means, co-axial reels adapted to be driven through said transmission means, and a record tape extending between and wound on said reels.

6. In a drive system for a sound record tape, the combination of a reversible drive motor, two co-axial relatively rotatable transmission means driven by said motor, an over-running clutch and a slip driving connection in one of said transmission means, co-axial reels adapted to be driven through said transmission means, a record tape extending between and wound on said reels, and means for regulating the speed of said motor inversely with the quantity of tape reeled on the reel driven by the other transmission means.

7. In a drive system for a sound record tape, the combination of a reversible drive motor, a shaft and a. concentric gear driven by said motor. roller ratchet clutch means on the end of said shaft, a clutch member opposed to said clutch means and adapted to be driven therefrom for one direction of rotation of said shaft, a shaft driven by said clutch member, a reel mounted on said shaft. a slip drive connection between the motor and said reel, a rotatable sleeve geared to said gear and surrounding said clutch means and member and a portion of the last mentioned shaft, and a second reel mounted on said sleeve.

8. In a drive system for a sound record tape, the combination of a reversible drive motor, a shaft and a concentric gear driven by said motor, roller ratchet clutch means on the end of said i shaft, a clutch member opposed to said clutch means and adapted to be driven therefrom for one direction of rotation of said shaft, a shaft driven by said clutch member, a reel mounted on said shaft, a slip drive connection between the motor and said reel, a rotatable sleeve geared to said gear and surrounding said clutch means and member and a portion of the last mentioned shaft, a second reel mounted on said sleeve, and means for regulating the speed of said motor inversely with the quantity of tape on the last mentioned reel.

9. In a drive system for a sound record tape, the combination of a reversible drive motor, a shaft and a concentric gear driven by said motor, roller ratchet clutch means on the end of said shaft, a clutch member opposed to said clutch means and adapted to be driven therefrom for one direction of rotation of said shaft, a shaft driven by said clutch member, a reel mounted on said shaft, a slip drive connection between the motor and said reel, a rotatable sleeve geared to said gear and surrounding said clutch means and member and a portion of the last mentioned shaft, the gear ratio between said gear and sleeve being such that said gear rotates at substantially lesser speed than the shaft on which said gear is mounted, a second reel mounted on said sleeve, and means for regulating the speed of said motor inversely with the last mentioned reel.

quantity of tape on the y the other reel, including a one-way drive clutchl lU so arranged as to ,cause said other reel to be driven only in a direction to draw tape from -said one reel, said driving interconnection being arranged to have an over-drive tendency on said other reel, and a frictional slip clutch in said driving interconnection adapted to slip sufcient- 1y that said other reel is permitted t0 travel at the speed determined by the rate of arrivai of the tape from said one reel. l

HERMAN S. HELLER.

DONALD E. ROSS.

FORREST J. LILLY.