communication
further modification of the invention; with the tape inlet opening 57, and a shallow upper apace
Figure 12 is a fragmentary section on an enlarged scale 66 in communication with the tape outlet slot 58.
taken as indicated by the line 12--12 of Figure 11; and, An inner circular tape guide or guide core to fit into
Figure 13 is a cross sectional view ta!cen as indicated by ,5 the innermost turn of the helical tape coil C may be

pro-
the line 13--13 of Figure 11. vided in any suitable manner. In the preferred embodi-
Figures 1 and 2 show a device generally designated 20 ment of the invention the inner tape guide comprises a
which may be either a recording device or a play-back de- plurality of small rollers 67, there being a pair of the
vice. For the purpose of disclosure it will be described rollers on each side of the diametric slot 61. In this par-
as a player or play-back device. Figures 1 and 2 also gO ticular construction each. of the rollers rests flat on the
show a disk-shaped cartridge, or unit, generally designated turntable 22 but is rotatably held in position by an

vxle
21, containing a roll of sound tape, the cartridge being pin 68 that extends upward from the roller into a corre-
shown in operating position on the play-back device. spondbag hole 79 in the partition 60.
The bottom of the cartridge 21 is formed in part by a An alternate form of inner guide core may comprise
turntable 22, best shown in Figures 2 and 3 which sup- 8,5 a smooth cylindrical wall extending downward from

the
ports a coil C of the endless cellulose acetate sound tape. partition 60. Figure 8, by way of example, shows such
Extending laterally from the cartridge 1 is a loop L of an arcuate wall 70, the opposite ends of which form an
the endless tape for cooperation ith reproduction openbag 71 through which the tape may be led from the
innermost turn of the helical coil C.
head 23.
The particular player 20 shown in the drawings has a 40 As best shown in Figure 2, one leg 75 of the tape loop
box-like casing 26 which encloses suitable mechanism ac- L enters the inlet opening 57 of the callridge 'to feed

the
tuated by a motor 27. The player has sxfitable manually helical coil C at its outermost turn. At the same time the
operable controls including at least one rotary knob 28 tape of the innermost turn of the coil after passing around
and is provided with suitable wires 29 which may include the four rollers 67 of the inner guide core, wraps

partially
wires for connection to a loudspeaker (not shown), as 4 around the fourth roller and then passes upward

through
well as wires for energizing the motor 27. the diametrical slot 61 in the partition 60 into the shallow
The reproduction head 23 provides the operating zone upper space 66. The outgoing tape then moves across
through which the endless tape is to be passed and the the upper surface of the partition 60 and out through the
player 20 drives and guides the tape through this zone. slot 58 for change in direction around the wire of the loop
For this purpose the player includes a driving means in 0 59 to become the second leg 76 of the loop L.
the form of the usual capstan 31 and a cooperating pros- Preferably, suitable means is provided to fix the rotary
sure roll 32 which holds the traveling tape against the position of the shell of the cartridge 21 when the cartridge
ß ß - is placed on the player 20. For this purpose the cartridge
periphery of the cap.stan..On .the oppo½tsdud tle  may haven downwardly extending peripheral

flange
e e
production head 23 s a sintame non-rotan g g. -
while bottom wall 55 may be provided with a small hole
ber 33 and a cooperating light pressure finger 34 mounted
on an upright spindle 35. Suitable yielding means con- 77 to receive an anchoring pin or stud 78 mounted on
cealed in the casing 26 acting on the spindle 35 urges the upper surface of the player, as best shown in Figure 5.
the pressure finger 34 towards the guide member 33 to The purpose of the peripheral flange 55a is to fi around
press the traveling tape 19 against the gnide member. and be engaged by rbag-shaped plate 81 fixedly mounted
In the particular arrangement shown, both the pressure 60 on the top of the player 20 concentrically of the shaft

45.
roll 32 and the guide member 33 are adapted for retrac- Preferably, but not necessarily, suitable guide pins for
tion laterally away from the path of the traveling tape. the incoming tape are provided inside the cartridge 21.
Such retraction is accomplished by pulling a small handle Thus Figure 2 shows a pair of spaced guide pins 78
36 outward from its normal position to the dotted posi- mounted between the bottom wall 55 and the partition
tion indicated at 37 in Figure 2. The handle 36 is the up- 6 60 on opposite sides of the balet opening 57 and

again
turned end of a horizontal slide in the player casing that on the opposite side of the shell shows a similar single
is urged towards its normal position by suitable spring guide pin 80. ß
means concealed in the casing 25. Mounted on this slide To place the cartridge 21 on the player 20, the axial
is an axle pin 40 for the pressure roll 32 and a pin or pin 46 of the turntable 22 is first seated in the bore 47
screw 41 carrying the guJcle member 33, these two mere- 70 at the upper end of the shaft 45 and then the shell

of
bers extending upwardly through slots 42 and 43, respec- the cartridge is manipulated o cause the stud 78 on

top
tively, in the top of the casing 26. of the player to enter the hole ?? in the bottom wall 55.
The motor 27 drives both the cap,tan 31 and an upright The cartridge is then released to rest on the player with
shaft 45 that is adapted to drive the turntable 22 in the the cartridge rim 55a surrounding and engaging the ring-
bottom of the cartridge 21. As shown in Figures 3 and 6, ? shaped plate 81. With the handle 36 pulled outward

to
the turntable 22 has an axial pin 46 that removably seats the dotted position 37 of Figure 2, it is a simple ma/ter
in a bore 47 in the end of the shaft 45 and the underside to place the loop L of the endless tape in proper posi-
of the turntable is provided with a suitable projection or tion around the guide member 33 and the capstan 31.

Re-
lug 48 positioned for engagement by a radial pba ,1.9 on lease of the handle 36 to return to its normal position
the shaft. The abutment of the radial pin 49 against the 80 brings the pressure roll 32 against the tape on the

capstan
lug 48 causes the turntable 22 to rotate with the shaft 45. 31 and also causes the guide member 33 to shift to its
The preferred construction for the cartridge 2t may normal position with the pressure finger 34 lightly hold-
be understood by referring to Figures 2, 3 and 7. In this ing the tape against the guide member. As will be ex-
form the cartridge 21 has a thin-walled shell comprising a plained, normal operation inherently places both legs 75
top wall 53, a circumferential wall 54 and a bottom wall t3'.,3 and 76 of the tape loop L under a certain degree

oœ ten-
Page 5
9,699,389
$ 6
sion so that any slackness in the tape loop when the loop. For handling cellulose acetate sound tape the turn-
cartridge is first mounted on the player quickly disap- table surface should be relatively smooth. Polished or
pears.
semi-polished metal has bcn found satisfactory.
The present invention is primarily concerned with the When the turnta.ble is rotated at the proper angular
behavior of the helical coil on the turntable 22 and is 5 speed the helical coil forms a characteristic pattern with
directed to .the problem of so operating and/or so modi- an outer zone of compact turns and an inner zone of
fylng the described basic arrangement as to secure the compact turns, with these .two zones separated by an in-
desired control over the coil behavior. As heretofore termed;ate zone of loose turns as may .be seen in cross-
indicated, the requisites are slippage to the desired degree section in Figure 3. If a coil selected at random 'is

placed
among the .turns of the coil and tension to the desired 10 on such a turntable and the speed is regulated soiely by
degree in both the in-going leg 75 and the out-going leg trial and error until tile coil takes the characteristic pat-
76 of the tape loop.
tern described, it will be found that the neutral circle lies
The behavior or action of the tape coil on the turn- in the intermediate zone of loose turns. An important
table is determined by a complex set of factors including, advantage of making the above-mentioned friction

gradi-
among others, friction between the coil and the turntable 15 ents gradual is the consequence widening of the intel'-
surface on which it rests, the character of the .tape sur- mediate loose zone.
faces in face-to-face contact among the turns of the coil, Rotating the turntable at such a speed relative to the
electrost.atic adhesion among the .turns, the tension in both
rate of linear travel imparted to the tape by the capstan
legs of the tape loop with special reference to tile in- 31 is not always sufficient, alone, to cause the tape coil
going leg 75, and the angular velocity .of the turntable. 20 to behave in the desired manner. Often further steps
it has been found that the problem of controlling the must be taken to minimize a certain tendency for .the
action of tile coil on the turntable may be solved largely, coil to act in an unstable manner. It has been found
and in some instances entirely, .by providing a turntable that the coil is usually stable and otherwise satisfactory
:surface that will have a relatively light frictional effect in its action when the var;ous factors involved cause the
on the turns of the coil and by the further provision of 25 coil to take a substantially circular configuration con-
rotating the turntable at a certain rate or within acer- ccntric to the axis of rotation of the turntable.
rain range of angular velocities relative to the linear speed Apparently the tension in tile in-going leg 75 of the
imparted to the tape by the driving capstan 31. tape loop tends to distort the coil to elliptical configura-
It can be readily understood that the speed of rota- tion with resulting increased friction among the turns
tion of the turntable may be ma.tched with .the approxi- 30 of the coil at the two ends of tile maior axis of the

ellipse.
mate linear speed of any one turn of the helical coil but Under such conditions the coil tends to become unstable
will then differ from the rate of travel of all the other as evidenced by pronounced oscillation on the turntable
turns of .the coil. Thus, if the rate of movement of the
surface of the turntable is equal to .the rate of move-
ment of the tape at the innermost turn of the helical coil, 85
the st.r.face of the turntable will move faster than all the
reintuning turns of the coil, and, conversely, if the sur-
face speed of the turntable matches the outermost turn
of the coil the surface of the turntable will move slower
than the rest of the turns of the coil. 40
.For convenience, the concentric circle of points on the
turntable that travels at the same speed as the linear speed
of tile tape will be termed the neutral circle. I have dis-
co,ered that the speed of the turntable should be such
that the diameter of the neutral circle is greater than 1.5
the diameter of the innermost turn of the helical coil but
less than the diameter of the outermost turn of the coil
and the tension in one or both of the legs of the tape
loop may approach the breaking point.
In some instances a satisfactory solution to the above
problem is to take some appropriate step to reduce the
friction among the turns of the coil. If 'the turns of the
coil slide freely past each other appreciable increase in
face-to-face pressure among the turns caused by elliptical
distortion of the coil may be tolerated. In this regard,
a feature of the preferred practice of my invention is the
continual treatment of the surface of the tape with a suit-
able material to minimize adhesion among the turns of
the coil. For this purpose the traveling tape is brought
into contact with a graphite surface in some suitable man-
ner. In the described embodiment of the invention it is
necessary merely to make the guide pin 78 of graphite or
and that optimum results with the present type of sound ot material including graphite as an ingredient. Graphite
tape are obtained by operating the turntable at a rate to in a clay-binder such as the "lead" in a lead pencil serves
place the diameter of the neutral circle substantially closer 50 the purpose well and a guide post of this

compos;tion has
to the diameter of the innermost turn of the coil. Such a long service. The effect of the graphite has been ex-
a neutral circle is indicated by dash-dot lines at 84 in plained heretofore.
Figure 4.
When necessary, a direct attack on the tendency of
At the neutral circle 84 the frictional effect of .the the coil to become elliptical may be made by removing,
rotating turntable surface on the .traveling tape is sub~ .56 nullifldng or modifying the distorting forces. In some
stantially zero, but for each successive turn of the coil of instances the addition of the guide pin 80 has the de-
lesser diameter than the neutral circle, the surface of the
sired corrective effect, apparently, in part because it
turn.table travels at a lower speed than the tape end, on creates a run of tape between the guide pin 80 and the
the other hand, the speed of the surface of the turn- graphite pin 78, which run presses against the periphery
table is progressively greater than the linear speed of the ;0 of the coil as may be seen in Figure 4.
tape in each successive turn of larger diameter than the In many instances a more effective step to correct the
neutral circle. Thus the surface of the turntable tends tendency of the coil to become elliptical and unstable
to retard the inner turns of the coil frictionally and at on the turntable and too taut ill the loop is to provide
.the same time tends .to accelerate the outer turns fric- suitable protuberances on the surface of the turntable for
tionally. The retardation effect on the inner turns causes 63 contact with the turns of the coil. In the preferred

prac-
the inner turns t.o tighte., slightly around the inner guide tice of the invention, the turntable is a disk of thin
core comprising the four rollers 67. This retardation or polished metal and the protuberances are formed merely
tightening effect on t,he inner turns of the coil opposes by raising or off-setting the metal to form a luraht
.the pull of the driving, capstan 31 and thus creates the small bosses Such bas ......... P ' y of
des;red degree of tension in the out-going leg 76 of the , . ß .  ....... ay oe termed, for example,
7 oy using a sintable pointed punch against the under-
tape loop. On the other hand, the tendency of the re- side of the metal.
tat;ng surface of the turntable to accelerate the outer As shown in Figures 4 and 7, the plurality of bosses
tnrns of the coil not only tends to make the outer turns 85 may be arranged in three radial rows. Tile bosses
compact but also creates sufficient pull on the tape from
. may be arranged in other patterns, for example, iu a
the capstan 31 to place the in-going leg 75 of the tape 75 pattern of concentric circles as shown in Figtlre 9. The
under the desired degree of tension.
løøl can be seen that there is what may be termed a protuberances may also be in the form of curved ribs on
retarding frictional gradient extending radially inward the upper surface of the turntable, for example, in the
from the neutral circle and a similar accelerating fric- form of two circular ribs 86 as shown in Figure 10.
tionai gradient extending radially outward from the 80 In each instance the protuberances, whether in the
neutral circle. It is contemplated that the character of form of a boss or a rib, or some other form, move in
the turntable surface will be such that these two gradients a concentric path and therefore cut across the eccentric
will be relatively gradual and will have maximum values or hclical turns of the coil and thus tend continuously
at the inner and outer turns respectively just sufficient to to cause relative lateral movement among the turns. As
maintain the desired .tension in the two legs 'of the tape 85 a result the turns are continually disturbed to sufficient
Page 6
7
,699,88
8
extent to cause the turns to continually adjust relative to
each other by slippage.
A further expedient to correct elliptical distortion that
has been found to be satisfactory, especially with rela-
tively large coils of sound tape,. is to. add a b.l, ade or
metal strip to support part of the coil auove me sur-
face of the turntable. Figures 11 and 12 show such a
turntable has separate protuberances spaced at different
radial distances on its supporting face.
6. In an apparatus of the character described for run-
ning an endless flexible tape through an operating
zone with the tape forming a spiral coil and with a loop
of the tape extending through said operating zone from
the inner and outer turns of the coil, the combination of:
a turntable to support said spiral coil; a guide positioned
blade 90 extending radially inward across the top of the
in the region of the axis of the turntable to be embraced
turntable, the outer end of the blade being anchored on
the peripheral wall 54 of the reproduction unit. In this 10 by the inner turn of the coil; means to engage said ta.pe
practice of the invention the ingoing leg of the tape loop at said loop to pull the tape from the inner turn of tiae
indicated by the dotted line 91 in Figure 1.1 reaches the coil to pass the outer turn of the coil at a given linear
coil tangentially at the point 92 and the blade 90 is speed; and means to rotate said turntable to match
positioned substantially diametrically opposite from the said linear speed at a concentric circle on the turntable
point 92. The effect of the blade 90, of course, is to 15 larger than the cross dimension of said guide, but less
remove the frictional contact of the turntable from ap N than the diameter of the outer turn of the coil whereby
proximately half the undersurface of the coil and to sub* the turntable frictionally opposes linear movement of the
stitute retarding frictional contact across the surface of tape in the inner turns of the coil and frictlonally tends
the blade. It has been found that such an interposition to increase the linear speed of the tape in the outer turns
of a radial blade will usually cause a coil to change from 20 of the coil, thereby forming three zones in the coil,
a troublesome elliptical configuration to a more circular namely, an inner zone of compact turns around said guide
trouble-free configuration. The blade 90 may be of rela- where the turntable frictionally opposes movement of the
tively rigid material spaced above the paths of move- tape to create tension in one leg of said loop, an inter-
ment of the bosses 85 or may be of flexible material and mediate zone of loose turns in the region of said circle,
positioned low enough to be displaced upward by each  and an outer circumferential zone of compact turns

where
row of the bosses. In the latter arrangement the blade the turntable tends to frictionally drive the tape faster
continually vibrates the coil to facilitate slippage of the than said given linear speed to create tension in the other
leg of the loop, said turntable including separate
coil turns.
It has been found that the tendency of the coil on the protuberances spaced at different radial distances on the
turntable to become elliptical and unstable may also be :50 supporting face of said turntable.
reduced to satisfactory degree simply by tilting the turn- 7. An apparatus as set forth in claim 6 in which the
table axis so that the surface of the turntable is inclined normal to the supporting surface of said turntable and
downwardly in the direction of travel of the in-going the plane of the turntable are inclined away from said
leg of the tape loop. Thus, with reference to Figures engaging means.
11 ad 13, instead of adding the blade 90, the turntable 8 8. In an apparatus for running an endless flexible
may be inclined slightly to place the lowest point on tape through an operating zone with the tape forming a
the diameter that is parallel with the in-going leg 91, spiral coil and with a loop of the tape extending through
in other words, to place the lowest point at the pe- said operating zone and including outgoing and ingoing
ripheral point 95 in Figures 11 and 13. The inclination, legs forming part of the inner and outer turns of the coil
which is not critical, may be for example at a drop of 40 respectively, the combination of: a turntable to support
1" for IT' of diameter. Thus if the diameter of the said spiral coil; engaging means to engage the outgoing
leg of said tape loop to pull the tape from the inner turn
turntable at the point 95 is 6" the point 95 may be one-
half inch below the opposite point on the same diam-
of said coil to pass to the outer turn of said coil for
eter. The proper angle of inclination may be readily movement through said operating zone; means to rotate
found by a simple experiment, and, of course, the shaft 4 said turntable to feed the tape to said engaging mean.

s;
45 for driving the turntable as well as the surrounding first guide means positioned adjacent one side of said
top surface of the player 20 will be inclined accordingly. coil adapted to guide said ingoing leg from said engag-
While the foregoing disclosure is directed to the prob- ing means and second guide means positioned substan-
leto of handling a thin flexible sound tape of cellulose tially on the opposite side of said coil from said first
acetate it is obvious that the same principles may be ap- 50 guide means and adapted to guide the ingoing leg of

said
plied to the handling of other kinds of tape. It will tape loop onto said coil whereby said ingoing leg is
also be apparent to those skilled in the art that various tangent to said coil at two points substantially opposite
changes, substitutions and other departures from my dis* each other.
closnre may be made within the spirit and scope of the 55 9. The combination set forth in claim 8, in which
appended claims. one of said guide means includes a bearing surface of
Having described my invention, I claim: graphite against which said ingoing leg of tape bears.
1. in an apparatus of the character described for 10. In an apparatus for running an endless flexible
rnnning an endless flexible tape through an operating zone tape through an operating zon.e with the tap

or?mg,
with the tape -forming a spiral coil and with a loop of spiral coil and with a loop of the tape extending tiarougn
the tape extending through said operating zone from the 130 said operating zone and including outgoing and

ingoing
inner and outer turns of the coil, the combination of: legs forming part of the inner and outer turns of the
a turntable to support said spiral coil, said turntable hay- coil respectively, the combination of: a turntable to sup-
ing separate protuberances spaced at different radial dis- port said spiral coil; means to engage the outgoing leg
tanccs on its supporting face; means to engage said loop t35 of said tape loop to pull the tape from the inner turn
to pull the tape from the coil for movement through said of said coil to pass to the outer turn of said coil for
operating zone; and means to rotate said turntable to movement through said operating zone; means to rotate
feed-the tape from said coil to said engaging means. said turntable to feed the tape to said engaging means;
2. An apparatus as set forth in claim 1 in which said and a stationary radially directed blade adiace. nt. the, sur;
protuberances are in the form of a plurality of bosses. 70 face of said turntable and positioned to lift tlaat sine or
3. An apparatus as set forth in claim 1 in which said said spiral substantially opposite the point of tangency
protuberances are in the form of curved ribs. of the incoming leg to said coil, out of contact with the
4. In an apparatus of the character described for turntable.
running an endless flexible tape through an operating 11. In an apparatus for running an endless flexible
zone with the tape forming a spiral coil and with a loop 7 tape through an operating zone with the tape forming a
of the tape extending through said operating zone from spiral coil and with a loop of the tape extending through
the inner and outer turns of the coil, the combination of: said operating zone and including outgoing and ingoing
a turntable to support said coil; means to engage said loop legs forming part of the inner and outer turns of the
to pull the tape from the coil and to feed the tape back coil respectively, the combination of: a turntable to sup-
to the coil, the axis of said turntabl.e being inclined so 80 port said spiral coil; engaging means positioned at one
that the surface of the turntable is inclined downwardly side of said coil to engage said tape loop to pull the
in the direction of travel of the tape fed back to the coil; tape from the inner turn of said coil to pass to the outer
and means to rotate said turntable in the direction to turn of said coil for movement through said operating
zone; means to rotate said turntable to feed the tape
feed the tape to said engaging means.
5. An apparatus as set forth in claim 4 in which said 8 to said engaging means; and a guide means positioned
Page 7
9
2,699,332
lO
at a side of said coil substantially opposite to said one
side at which said engaging means is positioned, to guide
the ingoing leg of said tape loop onto said coil whereby
said ingoing leg is tangent to said coil at two points sub-
stantially opposite each other.
12. The subject matter of claim 4, including also a
graphite bearing surface for the tape.
References Cited in the file of this patent
UNITED STATES PATENTS
2,238,719 Tartas ................ Apr. 15, 1941
2,285,070 Weber ................. June 2, 1942
2,398,639 Heyer ................ Apr. 16, 1946
2,426,838 Miller ................. Sept. 2, 1947