Endless microcassette tape

A microcassette tape comprising a tape housing including top and bottom case halves, a reel, a tape mounted on said reel, a rotating shaft for the tape reel, a pinch roller provided at the front of the tape housing, and a capstan between which the tape passes during endless revolutions of the tape. A guide is provided for preventing the tape from being misdirected and caught around the pinch roller and a wall is provided as a part of the tape housing for preventing the tape from slackening as it passes between the pinch roller and the capstan on a tangential path to the guide member which prevents the tape from being caught by the pinch roller. A further guide element is provided which prevents the tape from falling off the tape reel. A hole is provided in one of the halves of the tape housing which permits insertion of a shaft member for taking up any tape slack which develops in the passage of the tape from the tape reel to the pinch roller.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to a continuous microcassette tape 
and more specifically to a microcassette or case for use in such a manner 
that the tape housed therein is useable for hours to reproduce responsive 
messages carried in general industrial equipment, such as telephone 
message recorders and toys having a mechanism for voice recording and 
reproduction. 
2. Discussion of Related Art 
The prior art to which the present invention is directed includes the art 
of endless cassette tapes described in U.S. Pat. Nos. 3,764,084 and 
4,367,850. Such an endless cassette tape is capable of continuous travel 
because the tape is pulled off the innermost convolution and is returned 
to the outermost convolution, as a reel turns. 
In case the quantity of the tape let out is greater than that of the tape 
being wound up, the tape will slacken. The slackened tape may be caught 
under a pinch roller and caused to fall off the reel. When the tape has 
slackened, moreover, the cassette must be disassembled and the reel must 
be turned manually in order to nullify the slackening. As a result, it is 
necessary to prevent such a tape from slackening. 
The microcassette tape tends to be caught under a pinch roller particularly 
because the radius of the roller is small and this has resulted in an 
urgent need to meet the demand for endless microcasette tapes capable of 
stable travel. 
On the other hand, a tape recorder containing a microcassette tape is 
normally compact and often carried as a portable recorder though it may 
sometimes be placed in a fixed position. In the case of the former, the 
endless tape is subjected to vibration and rocking and caused to slacken 
when the recorder is moved. Furthermore, the tape could slacken while 
being transported for delivery. 
SUMMARY OF THE INVENTION 
Therefore, an object of the present invention is to provide a microcassette 
tape which will overcome the above noted disadvantages. 
A further object of the present invention is to provide a microcassette 
wherein the tape therein is free from slackening and retardation. 
Still, a further object of the present invention is to provide a 
microcassette tape wherein the tape is capable of stable travel for hours. 
To accomplish the purpose of the present invention, a guide plate is 
provided near a pinch roller to prevent the tape from being caught under 
the pinch roller and an off-reel preventive pin is installed on the outer 
peripheral edge of the reel to prevent the tape from falling off the reel. 
Moreover, in order to prevent the tape from slackening, there are provided 
a slackening preventive wall at the outer peripheral edge of the pinch 
roller and a guide hole for a recoil spindle for winding up the tape when 
the tape has slackened, the guide hole being bored just above the outer 
peripheral edge of the pinch roller in the tape housing.

DETAILED DISCUSSION 
Referring now to the accompanying drawings, the construction of an endless 
or continuous microcassette tape embodying the present invention will be 
described. 
In FIG. 1 there is seen the endless microcassette tape according to the 
present invention which comprises a tape housing 1, including a top case 
1a, bottom case 1b, machine screws 2, tape 3, reel 4, reel rotating shaft 
5, pinch roller 6, a pinch roller rotating shaft 11, a tape pad 12, an 
opening 13, an area 14 facing a head, a guide 15 for preventing the tape 
from being caught, a wall 16 for preventing the tape from slackening, an 
off-reel preventive tape pin 17, a hole 18 for guiding a shaft for rolling 
up any slackened tape, guide poles 19, tape support plate 20, and capstan 
21 (FIGS. 2, 5, 6). 
Guide for preventing the tape from being caught (15) 
The guide 15 is provided to prevent the tape from adhering to and being 
caught under the pinch roller 6 when the tape is left unmoved for hours 
between the capstan 21 and the pinch roller 6. 
If the tape is left unmoved for hours in such a state such that it is ready 
for use in reproducing a recorded voice therefrom, it may adhere to the 
pinch roller at a point A on its outer periphery, opposite to the capstan 
21, as shown in FIG. 2. Normally, the diameter of the capstan 21 is about 
2 mm and the diameter of the pinch roller is about 7 mm. The pinch roller 
is made for example of a synthetic rubber prepared from, e.g., neoprene. 
In the case when the tape adheres to the pinch roller, the tape sticking 
at the point A moves on the circumference of the pinch roller and winds 
therearound. The tape coils around the outer periphery of the pinch roller 
several times and ultimately the endless tape is damaged. In the present 
invention, the guide 15 (FIG. 2) is provided for preventing the tape from 
being caught under the pinch roller by forcing the tape to separate from 
the outer peripheral surface of the pinch roller, the guide 15 having a 
separating end face 15a and a flat end face 15b for use in preventing the 
tape from being caught under the pinch roller 6. The separating end face 
15a forms an acute angle with the flat end face 15b and is spaced about 
0.3 mm apart from the outer peripheral surface of the pinch roller 6. The 
surface of the flat end face 15b is arranged so that it is positioned 
above the tangent with the pinch roller 6. The guide 15 is thus installed 
to make the tape sticking to the pinch roller 6 peel off and consequently 
the tape is allowed to travel smoothly without being caught under the 
pinch roller 6. 
Off-reel preventive tape guide (17) 
The outermost peripheral portion of the cassette tape wound on the reel may 
slacken because of vibration and the like during the transportation 
thereof or while it is being driven and, as a result, protrude from the 
outer periphery of the reel. Provided the quantity of the endless tape 
thus let out is equal to that of the tape being wound up, the one edge of 
the tape must be pulled out to take up the slackened tape by rotating the 
reel, but this will result in an abnormal operation because the tape which 
has slackened or fallen off the reel will be damaged. Moreover, the size 
of the microcassette allows no room for a further increase in the size of 
the reel so as to prevent the tape from falling off the reel. As shown in 
FIG. 3, at least one off-reel preventive guide is provided, e.g. in the 
form of pin 17, in a portion of the top case 1a of the tape housing 1 
according to the present invention, the guide being positioned slightly 
closer to the reel rotating shaft 5 than the outermost peripheral edge of 
the reel, so that the tape is prevented from falling off the reel. The 
lowermost portion of the off-real preventive guide or, in this case, tape 
pin 17, is so arranged that its length is equivalent to about two-thirds 
of the width of the tape 3. The diameter of the pin should preferably be 
set at about 2 mm, provided the reel is about 21 mm in diameter. The 
off-reel preventive tape pin ensures that the tape is prevented from 
falling off the reel. Without the pin, the tape soon begins to slacken in 
the radial direction from the reel rotating shaft. As a result, the tape 
falls off the reel 4 as the tape is wound on the outer periphery of the 
real. As a result, the tape jams up and stops traveling. 
Wall for preventing the tape from slackening (16) 
FIG. 4 is a partial view of the periphery of a pinch roller for a 
conventional microcassette tape. When the cassette tape is moved while it 
is in a slackened state, it may grow into what looks like a folded fan, as 
shown in FIG. 5, and will not roll up on the reel because the space 
between the pinch roller and the wall is extremely narrow, such as from 
about 1-2 mm. 
FIG. 5 is a partial view of the periphery of the pinch roller according to 
the present invention, wherein the wall 16 for preventing the tape from 
slackening is installed to prevent the tape from being caught under the 
pinch roller and to keep it smoothly traveling, the aforesaid wall having 
a curved surface about the outer periphery of the pinch roller. Given that 
the radius of curvature of the curved surface of the aforesaid wall 16 is 
R, then R is greater than the radius of the pinch roller and the center 
thereof stands back from the central axis of the pinch roller in an 
opposite direction away from the capstan 21. 
Hole for guiding a shaft for rolling up the slackened tape (18) 
As shown in FIG. 6, slackened tape 3 may protrude from the case. Being that 
the configuration of the present invention is different from the 
conventional cassette tape, the protruding endless tape normally could not 
be rolled up. In order to roll up the tape, the machine screws 2 used to 
assemble the housing 1 would have to be unscrewed and then the slackened 
tape rolled up manually. However, such a solution is not practical and 
therefore a much more simple means is required for rolling up the tape. 
The aforesaid means of rolling up the tape according to the present 
invention comprises fitting a shaft 24 into the hole 18 prearranged in the 
case, as shown in FIG. 7, holding the tape between the pinch roller and 
the shaft and turning the shaft in the roll-up direction. The hole for 
guiding the shaft for rolling up the tape is characterized in that the 
outermost periphery of the hole is arranged to be in contact with the 
outermost periphery of the pinch roller. The shaft to be actually inserted 
into the hole may be articles of daily use, such as a round matchstick or 
a toothpick and the like and no special tool is required. 
The invention being thus described, it will be obvious that the same may be 
varied in many ways. Such variations are not to be regarded as a departure 
from the spirit and scope of the present invention, and all such 
modifications as would be obvious to one skilled in the art are intended 
to be included within the scope of the following claims.