Disk producing method and apparatus

A photo film cassette includes a spool core (13) on which photo film is wound in a form of a roll. A cassette shell (3, 4) contains the spool core in rotatable fashion. In each of a pair of disks (16, 17), a bearing hole (16a, 17a) is formed. The disks are secured to first and second ends of the spool core, and regulate edges of the photo film. To produce at least one kind of disk, a continuous sheet (27, 78, 88, 162, 171, 215) of thermoplastic synthetic resin is partially masked with a mask plate (48, 87, 160, 161, 170). A portion of the sheet emerging out of the mask plate is heated at temperature higher than a softening point of the sheet. The emerging portion is subjected to vacuum/air-pressure forming, so as to form a disk-like portion (20) in the sheet. The bearing hole and a contour of the disks is cut in the disk-like portion, to produce the disks.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a disk producing method and apparatus for 
a photo film cassette. More particularly, the present invention relates to 
a method and apparatus for producing a plastic disk with high quality to 
be used in a photo film cassette. 
2. Description Related to the Prior Art 
U.S. Pat. No. 4,423,943 discloses a type of photo film cassette, of which a 
leader of unexposed photo film is precontained in the cassette shell, and 
advanced to an outside of the cassette shell when a spool is rotated in an 
unwinding direction. The spool is constituted by a spool core and two 
disks, which are disposed on the spool core, for contact with the ends of 
a roll of the photo film, to render the turns of the photo film neat. In 
the cassette of the leader-advancing type, it is necessary to transmit 
rotation of the spool to the roll of the photo film. To this end, the 
disks of the spool are provided with respective ring-like lips formed on 
their periphery and projected toward one another. The ring-like lips are 
located to cover edges of the outermost turn of the photo film, and 
prevent the roll from being loosened. Such a cassette is suggested in U.S. 
Pat. Nos. 4,834,306, 4,848,693 (corresponding to JP-A 2-18545), 5,031,852 
(corresponding to JP-A 3-214153), 5,271,577 (corresponding to JP-A 
3-37645), and 5,407,146 (corresponding to JP-A 3-37645). 
To advance the leader of the photo film, it is necessary to spread both 
disks in the vicinity of a photo film passageway, to release the ring-like 
lips from regulation. The disks are rotatable, and are not rotated without 
being deformed. The disks are formed at the thickness of 0.3 mm or less. 
There is a suggestion of a disk producing method in U.S. Pat. No. 5,211,348 
(corresponding to JP-A 4-251841 and 5-119436). Continuous resin sheet of a 
thermoplastic type having small thickness is heated. The continuous sheet 
is deformed in accordance with the vacuum forming. The continuous sheet is 
moved into a punch/die set, where a punch device and a die device cut a 
circular contour and a bearing hole at each disk-like portion, to form the 
disks. However a shortcoming lies in that, when one or both surfaces of 
thin resin continuous sheet are heated by a heater, the continuous sheet 
is likely to be softened excessively, melted and stuck on the heater, and 
cut down. JP-A 5-147606 has a suggestion overcoming the shortcoming, and 
discloses a use of a mask plate having openings respectively greater than 
the contour of each disk to produce. The continuous sheet is masked by the 
mask plate. Portions emerging through the openings are heated. The portion 
excluded from the heating is cooled. The continuous sheet is subjected to 
the press molding. It is thus possible to reduce the extent of melting of 
the continuous sheet in the heater. 
The synthetic resin for disks must have strong characteristics with 
resistance to heat and flexural fatigue resistance, and are obliged to be 
expensive. If the number of produced disks per unit amount of the 
continuous sheet is low, disks become costly. JP-A 6-67360 has a 
suggestion for solving this problem, and discloses that disks are produced 
from continuous sheet with a great width in an arrangement of a zigzag or 
a grid. 
The disks must rotate without eccentricity in the cassette before the photo 
film can be advanced properly. Concentricity of the disks between the 
ring-like lips and the bearing holes should be acceptably high. The 
concentricity between the ring-like lip and the bearing hole depends on 
coincidence between a position of the continuous sheet for the vacuum 
forming, and a stop position of the continuous sheet for the punching. 
Also, concentricity between the bearing hole and the disk contour should 
be high. JP-A 61-51570 has a suggestion for obtaining high concentricity, 
and discloses forming positioning holes in the continuous sheet. 
Positioning pins are inserted in the positioning holes, while the vacuum 
forming is effected and while the punching is effected. 
To produce disks with precision, the continuous sheet subjected to the 
vacuum forming must be conveyed properly to a set position of a punching 
machine. For conveyance of continuous sheet or other similar material, 
conveying rollers, which are rotatable with the continuous sheet nipped, 
are widely used. Small changes in the set position are likely to occur due 
to play of the rollers when the continuous sheet is stopped by stopping 
the rollers. JP-A 5-147606, in view of this, discloses conveying holes 
formed near to edges of the continuous sheet. Conveying pins are inserted 
in the conveying holes, and moved intermittently as far as a predetermined 
amount, to convey the continuous sheet to the set position regularly. 
So far the vacuum forming in general has been used for producing articles 
not requiring high precision in size, such as vessels for edibles. There 
have been no successful techniques known in the art, for producing a disk 
with precision by the vacuum forming to be used in a photo film cassette. 
JP-A 5-147606 has a problem in that wrinkles are created in the continuous 
sheet in the course of the press molding, because a cooled portion of the 
continuous sheet is also pulled during the molding. JP-A 6-67360 in turn 
has a problem in difficulties in heating and forming the wide continuous 
sheet with high regularity. Disks as produced have considerably varied 
physical characteristics. 
In JP-A 61-51570, the positioning holes operate to fix the continuous sheet 
completely. When distortion occurs in the continuous sheet due to 
unevenness in the vacuum forming to change the size of the continuous 
sheet, the continuous sheet as distorted is punched in the punching step. 
Irregularity in sizes occurs between disks as products. The positioning 
holes and the conveying holes may be formed at the time of the vacuum 
forming. It is however likely that a punch and a die for cutting those 
holes are swollen by heat remaining in the continuous sheet imparted in 
the vacuum forming. Precision of the punch and the die sizes is therefore 
lowered. 
SUMMARY OF THE INVENTION 
In view of the foregoing problems, an object of the present invention is to 
provide a method and apparatus for producing a plastic disk from a sheet 
without creating wrinkles in the sheet. 
Another object of the present invention is to provide a method and 
apparatus for producing a plastic disk with high precision and regularity 
to be used in a photo film cassette. 
In order to achieve the above and other objects and advantages of this 
invention, a sheet of thermoplastic synthetic resin is partially masked 
with a mask plate. A portion of the sheet emerging out of the mask plate 
is heated at temperature higher than a softening point of the sheet. The 
emerging portion is subjected to vacuum forming, air-pressure forming, or 
vacuum/air-pressure forming in combination of vacuum forming and 
air-pressure forming, so as to form a disk-like portion in the sheet. The 
bearing hole and a contour of the disks is cut in the disk-like portion, 
to produce the disks. 
In a preferred embodiment, at least one opening is formed through the mask 
device and having a size greater than the disks, the emerging portion 
emerging to be heated by the sheet heating unit while the sheet is 
accessed by the mask device. 
The mask heating device heats a mask device at the temperature 
10-50.degree. C. lower than the softening point of the sheet. 
In the present invention, the disk can be produced from a sheet without 
creating wrinkles in the sheet. 
In a variant of disk producing apparatus, the sheet has a predetermined 
size. A sheet supply unit, a sheet heating unit, a forming unit and a 
punching unit are arranged along one arc. An index table is disposed at a 
center of arrangement of the sheet supply unit, the sheet heating unit, 
the forming unit and the punching unit, the sheet being mounted on the 
index table, the index table being rotated intermittently, for passing the 
sheet through the sheet supply unit, the sheet heating unit, the forming 
unit and the punching unit. 
In another preferred embodiment, a retainable portion is formed in the 
sheet and near to an edge thereof when the disk-like portion is formed. 
The retainable portion of the sheet located in a conveying path is 
retained. The retainable portion while retained is moved in one direction 
within a predetermined range, so as to convey the sheet intermittently. 
A positioning portion associated respectively with the disk-like portion is 
formed when the disk-like portion is formed. The sheet is positioned with 
the positioning portion, in cutting the bearing hole and the contour of 
the disks. 
Furthermore, at least one first bend slit is cut in an outside of the 
disk-like portion to extend along part of a periphery thereof, the first 
bend slit rendering a position of the disk-like portion adjustable 
minutely relative to the sheet. 
The disk can be produced with high precision and regularity to be used in a 
photo film cassette.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) OF THE PRESENT 
INVENTION 
In FIG. 1, a photo film cassette 2 includes upper and lower shell halves 3 
and 4, a spool 5, a port shutter member 6, a lock 7, and a sticker or 
label 8. The shell halves 3 and 4 are respectively formed from plastics. 
The spool 5 is contained between the shell halves 3 and 4. The sticker 8 
is attached to the outside of the shell halves 3 and 4. 
A photo film port 10 is formed between the shell halves 3 and 4 for passage 
of photo film 9. The port shutter 6 for opening/closing the photo film 
port 10 is contained in a middle position of the photo film port 10. A 
separating claw 11 is formed on the lower shell half 4 in an innermost 
position of the photo film port 10, for separation of a leader of the 
photo film 9 around the spool 5 from the roll, to direct it to the photo 
film port 10. 
The spool 5 includes a spool core 13, a data plate 14, a barrel member 15, 
and disks 16 and 17. A trailer of the photo film 9 is secured to the spool 
core 13 and wound there-about. The data plate 14 is formed with a distal 
end of the spool core 13. The barrel member 15 is secured to another 
distal end of the spool core 13. The disks 16 and 17 are secured to the 
spool core 13 between the data plate 14 and the barrel member 15. There is 
a bar code sticker 18 on which a bar code is printed for representing 
various data related to the photo film 9, and which is attached to the 
data plate 14. The bar code is read by a camera or other devices. 
The barrel member 15 includes an indicator plate 15a for indicating a 
status of exposing the photo film 9 in externally visible fashion to a 
user, and a gear 15b for locking the spool 5. The indicator plate 15a is 
positioned inside any of a plurality of indicating windows formed in an 
end face of the shell halves 3 and 4, and shows one of unexposed, 
partially exposed, all exposed and developed statuses as information 
associated with each of the windows. When the port shutter 6 has a closed 
position, the gear 15b is engaged with the lock 7, which disables the 
spool 5 from rotating. When the port shutter 6 has an open position, the 
lock 7 is moved away from the gear 15b to enable the spool 5 to rotate. 
The disks 16 and 17 are shaped like a two-stepped dish and have respective 
bearing holes 16a and 17a through which the spool core 13 is inserted. 
Around the disks 16 and 17 are formed ring-like lips 16b and 17b, which 
cover ends of roll of the photo film 9 about the spool core 13, to keep 
the roll from being loosened in the photo film cassette 2. The disks 16 
and 17 are formed of flexible plastics for easy deformation during 
advancement of the photo film 9, and have thickness of 0.3 mm or less. 
In FIGS. 2A and 2B, four slots 23 in an arc shape are formed around the 
bearing hole 17a in the disk 17. An inner face of the barrel member 15 is 
provided with ratchet claws 24, which are inserted in two of the slots 23. 
When the spool 5 is rotated in an unwinding direction, the ratchet claws 
24 are engaged with the slots 23, to rotate the disk 17 with the spool 
core 13. When the spool 5 is rotated in a winding direction in reverse, 
the ratchet claws 24 rotate past the slots 23, not to transmit rotation of 
the spool core 13 to the disk 17. 
Transmission of rotation to the disk 17 is changed over according to a 
direction of rotating the spool 5. Friction is reduced by coincidence in 
rotation between the photo film 9 and the disk 17 about the spool 5 in 
advancement of the photo film 9. Only small force applied to the spool 5 
for rotation is required for advancement of the photo film 9. As the disk 
17 is rotated individually in rewinding of the photo film, the photo film 
9 is wound toward the inside of the ring-like lip 17b without hindrance. 
Before and after use of the photo film cassette 2, the leader of the photo 
film 9 is entirely wound in the photo film cassette 2. The port shutter 6 
has the closed position to close the photo film port 10. No ambient light 
comes into the photo film cassette 2 through the photo film port 10. The 
spool 5 is locked by the lock 7 and kept from accidentally rotating. When 
the port shutter 6 opens the separating claw 11 and the spool 5 is rotated 
in the clockwise direction, the leader of the photo film 9 is separated by 
the separating claw 11 to exit through the photo film port 10. 
A disk producing apparatus 26 of the present invention is described next. 
As illustrated in FIG. 3, the disk producing apparatus 26 is adapted to 
produce the disks 17. The disk producing apparatus 26 includes a sheet 
supply unit 28, a forming unit 29, a first punching unit 30, a second 
punch unit 31, a disk withdrawing unit 32 and a sheet winding unit 33, all 
of which are arranged on a stand 34. The sheet supply unit 28 supplies 
continuous sheet 27 of thermoplastic resin as material for the disks 17. 
The forming unit 29 applies heat to the continuous sheet 27 from the sheet 
supply unit 28, subjects the continuous sheet 27 to the 
vacuum/air-pressure forming, and forms plural disk-like portions, for 
example five (5) disk-like portions on the continuous sheet 27. The first 
punching unit 30 cuts the bearing hole 17a and the slots 23 in the 
disk-like portions. The second punching unit 31 cuts the contour of the 
disks 17 at the disk-like portions. The disk withdrawing unit 32 withdraws 
the continuous sheet 27 from the disk producing apparatus 26. The sheet 
winding unit 33 draws the continuous sheet 27 from the sheet supply unit 
28, while winding the continuous sheet 27 subsequent to the punching of 
the disks 17. 
The continuous sheet 27 is 0.15 mm thick, and formed of resin of 
polystyrene-modified polyphenylene ether with elastomer added thereto. The 
ratio of polystyrene and polyphenylene ether is 3:7. The proportion of 
elastomer is 12 wt. %. 
The sheet supply unit 28 is constituted by a drum 36 and a brake device 37. 
The continuous sheet 27 is wound on the drum 36. The brake device 37 
applies load to the drum 36 to apply tension to the continuous sheet 27 
while drawn by the sheet winding unit 33. The sheet winding unit 33 is 
constituted by a drum 38 and a motor 39. The drum 38 is adapter to winding 
the continuous sheet 27 as punched. The motor 39 rotates the drum 38. To 
guide the continuous sheet 27, guide rollers 40 are disposed in the disk 
producing apparatus 26 between the sheet supply unit 28, the forming unit 
29, the first punching unit 30, the second punching unit 31, the disk 
withdrawing unit 32 and the sheet winding unit 33. 
In the forming unit 29, a stationary support 43 is disposed on the stand 34 
as illustrated in FIG. 4. A movable support 45 is arranged over the 
stationary support 43, and movable vertically along guide shafts 44. A 
female mold plate 46 is mounted on the stationary support 43, and includes 
five (5) female molds 46a aligned in the conveying direction of the 
continuous sheet 27. A male mold plate 47 is mounted on the movable 
support 45, and includes five (5) male molds 47a. 
There is a mask plate 48 disposed between the supports 43 and 45 for 
holding the continuous sheet 27 between it and the female mold plate 46. 
The forming unit 29 also has an apparatus for heating the sheet. A sheet 
heater 49 is disposed beside the forming unit 29, to be inserted between 
the supports 43 and 45. To move the movable support 45 up and down, 
hydraulic cylinders, cams, and the like are used. 
There is an air mouthpiece 51 formed in the female mold plate 46 to come 
through each of the female molds 46a. The air mouthpiece 51 is connected 
to an air passageway 52 which is formed through the stationary support 43 
and comes to be open in a lateral face of the stationary support 43. A 
pipe 53 is secured to the stationary support 43 to connect the air 
passageway 52 to a vacuum pump for air suction. There is an air mouthpiece 
55 formed in the male mold plate 47 to come through each of the male molds 
47a. The air mouthpiece 55 is connected to an air passageway 56 which is 
formed through the movable support 45 and comes to be open in a lateral 
face of the movable support 45. A pipe 57 is secured to the movable 
support 45 to connect the air passageway 56 to a compressor for air 
pressurization. The air suction and the air pressurization keep the 
continuous sheet 27 into tight contact with the female molds 46a, to form 
disk-like portions. 
The mask plate 48 is rectangular as illustrated in FIG. 5, and has five (5) 
openings 59 formed through it and arranged at a regular interval in its 
longitudinal direction. The openings 59 have a diameter greater than a 
diameter of the disks 17. As illustrated in FIG. 4, the mask plate 48 is 
movable up and down in the vertical direction along guide shafts 60, which 
are disposed in positions inside positions of the guide shafts 44 for the 
movable support 45. There is a spring 61 having greater biasing force, 
arranged between the movable support 45 and the mask plate 48 and around 
each of the guide shafts 60. There is a spring 62 having smaller biasing 
force than the spring 61, arranged between the stationary support 43 and 
the mask plate 48 and around each of the guide shafts 60. With the springs 
61 and 62 balanced, the mask plate 48 when not in use has a position 
nearer to the stationary support 43 and shiftable between the supports 43 
and 45. 
The continuous sheet 27 is conveyed between the female mold plate 46 and 
the mask plate 48 lying over the same. Once the continuous sheet 27 stops 
being conveyed, the movable support 45 is lowered by the hydraulic 
cylinders, the cams, and the like at a small amount as illustrated in FIG. 
6. The spring 61 over the mask plate 48 is pressed, to bias the mask plate 
48 downwards along the guide shafts 60. The spring 62 under the mask plate 
48 is weaker than the spring 61, and are compressed by the mask plate 48, 
to squeeze the continuous sheet 27 between the mask plate 48 and the 
female mold plate 46. 
When the continuous sheet 27 is inserted between the female mold plate 46 
and the mask plate 48, the sheet heater 49 standing by beside the forming 
unit 29 is driven by an air cylinder or solenoid, and inserted between the 
movable support 45 and the mask plate 48 as illustrated in FIG. 7. The 
sheet heater 49 includes a block 49a and a cartridge heater 49b. The block 
49a is formed of material with high heat conductivity, such as iron or 
aluminum. The cartridge heater 49b is incorporated in the block 49a. The 
sheet heater 49 is controlled so that a surface of the block 49a has 
temperature of 400.+-.5.degree. C. Heat of the sheet heater 49 operates to 
portions of the continuous sheet 27 emerging through the openings 59 in 
the mask plate 48, to render the portions as hot as 150.degree. C. 
When the continuous sheet 27 is heated to a predetermined temperature, the 
sheet heater 49 is moved aside and out of the forming unit 29 by the air 
cylinder or solenoid. Only the portions of the continuous sheet 27 
required in the vacuum/air-pressure forming are heated, so that the 
continuous sheet 27 is not melted or stuck on the mold set in 
irrecoverable fashion. The continuous sheet 27 finishes being heated when 
its temperature as measured comes up to a predetermined value. It is also 
possible to measure preheating time experimentally for heating the 
continuous sheet 27 with the sheet heater 49, and to retract the sheet 
heater 49 upon the lapse of the measured time. 
As illustrated in FIG. 5, an inside of the mask plate 48 has a liquid 
passageway 64, through which hot liquid medium, such as water or specialty 
oil for applying heat, is circulated inside the mask plate 48. The liquid 
passageway 64 is disposed around the openings 59. The hot liquid medium is 
entered into one end of the liquid passageway 64, flows through the liquid 
passageway 64 to heat the mask plate 48 to the temperature 10-50.degree. 
C. lower than a softening point of the continuous sheet 27, and exited 
from another end of the liquid passageway 64 to the outside. Thus the 
portion of the continuous sheet 27 masked by the mask plate 48 is heated 
to the temperature lower than its softening point, and can be swelled at a 
smaller amount at the time of the forming. It is thus possible to avoid 
occurrence of wrinkles on the continuous sheet 27. 
As is not shown, distal ends of the liquid passageway 64 are connected to 
respective pipes having flexibility and resistance to heat. Distal ends of 
the pipes opposite to the liquid passageway 64 are connected to a liquid 
pump which is disposed in the stand 34 for the hot liquid medium. The 
inside of the stand 34 contains a liquid tank and a heater for heating the 
liquid medium, as well as the liquid pump. 
At the end of heating the continuous sheet 27, the sheet heater 49 is moved 
out of the space between the movable support 45 and the mask plate 48. The 
movable support 45 is lowered further by hydraulic cylinders, cams, and 
the like. With the movable support 45 lowered, the male molds 47a are 
inserted into the openings 59 formed in the mask plate 48 as illustrated 
in FIG. 8, and then into the female molds 46a. 
In lowering the movable support 45, the air pressurization is effected 
through the air mouthpiece 55 in the male molds 47a, to press the 
continuous sheet 27 against the female molds 46a. The air suction is 
effected through the air mouthpiece 51 in the female molds 46a, to keep 
the continuous sheet 27 in tight contact with the female molds 46a, to 
form five (5) disk-like portions 20 in the continuous sheet 27. Thus the 
vacuum/air-pressure forming in combination of the air pressurization and 
the air suction makes it possible to form the disk-like portions 20 with 
high precision, as the continuous sheet 27 is contacted on the mold set in 
tighter fashion than the uncombined use of either of the air 
pressurization and the air suction. The number of the five disk-like 
portions 20 is appropriate, because it is possible to have only small 
unevenness in heating and forming of the disk-like portions 20. 
The first punching unit 30 is described in detail next. As illustrated in 
FIG. 3, the first punching unit 30 includes a stationary support 30a and a 
movable support 30b. The stationary support 30a has a die secured thereto 
for forming the bearing hole 17a and the slots 23 in the disk-like 
portions 20. The movable support 30b has a punch secured thereto and 
movable vertically up and down along guide shafts 30c. The movable support 
30b is driven by the hydraulic cylinders, cams, and the like. Scraps 
created by forming the bearing hole 17a and the slots 23 in the first 
punching unit 30 are dropped through the die, passed through a path 66 
under the stationary support 30a, and exited through an exit 67 formed in 
a side of the stand 34. 
The second punching unit 31 is constructed substantially the same as the 
first punching unit 30, and includes a stationary support 31a and a 
movable support 31b. The stationary support 31a has a die secured thereto 
for forming the contour of the disk-like portions 20. The movable support 
31b has a punch secured thereto and movable vertically up and down along 
guide shafts 31c. The second punching unit 31 is also provided with a push 
back device known in the art, so that the disks 17 after being punched 
away can be returned into punch holes in the continuous sheet 27 after the 
punching. The disks 17 as punched are returned to the continuous sheet 27, 
of which conveyance causes the disks 17 to move to the disk withdrawing 
unit 32. 
The disk withdrawing unit 32 includes a support plate 69, a disk lift 70 
and an arm 72. On the support plate 69 is placed the continuous sheet 27 
in which the disks 17 is still kept together. The disk lift 70 removes the 
disks 17 from the continuous sheet 27 while lifting it. The arm 72 swings 
the disk lift 70 and moves it to a disk container 71. For the keeping of 
the disks 17 in the disk lift 70, air suction, electrostatic suction, or a 
mechanical grasping structure may be utilized. It is necessary that the 
disk lift 70 is released from the disk keeping upon movement to the disk 
container 71. It is also possible to eliminate the disk withdrawing unit 
32, and to exit the disks 17 through an exit formed in the stand 34 in a 
similar form to the exit 67 at the first punching unit 30. 
Operation of the above construction is described. As illustrated in FIG. 3, 
a starting command is entered into the disk producing apparatus 26, in 
which the continuous sheet 27 wound on the drum 36 in the sheet supply 
unit 28 is drawn by rotation of the sheet winding unit 33, and guided by 
the guide rollers 40. As illustrated in FIG. 4, the continuous sheet 27 is 
conveyed between the female mold plate 46 and the mask plate 48 in the 
forming unit 29. At the same time, the cartridge heater 49b in the sheet 
heater 49 is energized. The liquid medium, such as water or specialty oil 
for applying heat, starts being heated and flowing into the mask plate 48. 
The predetermined temperature is obtained by prestarting heating the sheet 
heater 49 and the mask plate 48, so that the time for heating the 
continuous sheet 27 can be short to raise efficiency in producing the 
disks 17. 
Once the continuous sheet 27 is stopped, the movable support 45, as 
illustrated in FIG. 6, is lowered at a smaller amount by the hydraulic 
cylinders, cams, and the like. Then the spring 61 biases the mask plate 
48, which compresses the spring 62 to squeeze the continuous sheet 27 
between it and the female mold plate 46. 
While the continuous sheet 27 is entirely squeezed on the mask plate 48, 
the sheet heater 49 is inserted between the movable support 45 and the 
mask plate 48 by the air cylinder or solenoid, as illustrated in FIG. 7. 
The block 49a of the sheet heater 49 has been heated to the temperature of 
400.+-.5.degree. C. At the same time as the insertion into the forming 
unit 29, the sheet heater 49 starts heating the continuous sheet 27. The 
sheet heater 49 heats only the portions of the continuous sheet 27 
emerging through the openings 59 in the mask plate 48, to render the 
portions as hot as 150.degree. C. 
Only the portions of the continuous sheet 27 required in the 
vacuum/air-pressure forming are heated, so that the continuous sheet 27 is 
not melted or stuck on the mold set in irrecoverable fashion. The hot 
liquid medium such as water or specialty oil is circulated through the 
liquid passageway 64. The portion of the continuous sheet 27 masked in 
contact with the mask plate 48 is heated to the temperature lower than its 
softening point by 10-50.degree. C. 
When the continuous sheet 27 is at the predetermined temperature, the sheet 
heater 49 is moved away from between the movable support 45 and the mask 
plate 48 by the air cylinder or solenoid. As illustrated in FIG. 8, the 
movable support 45 is further lowered by the hydraulic cylinders, cams, 
and the like. The male molds 47a are respectively inserted through the 
openings 59 of the mask plate 4B, and into the female molds 46a. 
At the same time as the descent of the movable support 45, a vacuum pump 
connected to the air passageway 52 of the stationary support 43 starts the 
air suction. A compressor connected to the air passageway 56 of the 
movable support 45 starts the air pressurization. Then the male molds 47a 
press the continuous sheet 27 against the female molds 46a, through which 
the continuous sheet 27 is sucked. The disk-like portions 20 are formed in 
the continuous sheet 27 with high precision. The continuous sheet 27 is 
not deformed in unwanted fashion, as retained between the mask plate 48 
and the female mold plate 46. The portion other than the portions with the 
disk-like portions 20 is also heated by the mask plate 48 and swellable 
sufficiently, so that no wrinkles or breakage occurs. 
The movable support 45, while lowered, is left to stand for a predetermined 
duration to cool the continuous sheet 27, and then raised again by the 
hydraulic cylinders, cams, and the like. The mask plate 48 is released 
from the bias of the spring 61, and has a position between the supports 43 
and 45, with the springs 61 and 62 balanced as illustrated in FIG. 4. The 
continuous sheet 27 restarts being conveyed. A section of the continuous 
sheet 27 having been provided with the disk-like portions 20 is conveyed 
to the first punching unit 30. 
In the first punching unit 30, the movable support 30b is lowered by the 
hydraulic cylinders, cams, and the like, to cause a set of a punch and a 
die to cut the bearing hole 17a and four of the slots 23 in the disk-like 
portions 20. The scraps created by the cutting are passed through the die 
and the path 66, and exited from the exit 67 in the stand 34. At the time 
of the cutting, five other of the disk-like portions 20 are formed by the 
forming unit 29 on the continuous sheet 27. 
In the second punching unit 31, the movable support 31b is lowered to cut 
the contour of the disk-like portions 20 from the continuous sheet 27 by 
means of the punch and the die. The disks 17 cut from the continuous sheet 
27 are returned to the continuous sheet 27 by the push back device. After 
the punching in the second punching unit 31, the movable support 31b is 
raised. The continuous sheet 27 is conveyed again. In the conveyance, the 
disks 17 are conveyed with the continuous sheet 27 and transferred to the 
disk withdrawing unit 32. 
In the disk withdrawing unit 32, the disk lift 70 removes the disks 17 from 
the continuous sheet 27 by sucking or grasping the disks 17. While the 
disk lift 70 retains the disks 17, the arm 72 rotates to move the disk 
lift 70 to a position above the disk container 71. Then the disk lift 70 
is released from the suction or grasping, to let the disks 17 drop into 
the disk container 71 which receives the disks 17. The disk container 71, 
when filled with a great number of the disks 17, is conveyed to a line of 
assembling the spool 5. In place of the disk container 71 as filled, a new 
container is positioned in the disk withdrawing unit 32. In repetition of 
those steps, the disks 17 are produced in successive fashion. 
In the above embodiment, the hot liquid medium such as water or specialty 
oil is used to heat the mask plate 48. It is possible to use electrically 
heated wires or a feeder slip ring. It is possible that the sheet heater 
49 is additionally operated to preheat the mask plate 48. Note that, if 
there is an undercut on a product to be formed by the vacuum/air-pressure 
forming, it is preferable to provide the female mold plate 46 with a 
push-out mechanism for pushing the continuous sheet 27 up. 
The number of the openings 59 in the mask plate 48 for defining the heated 
range of the continuous sheet 27 is equal to the number of the disk-like 
portions 20. However, the number of openings 75 in the mask plate 48 can 
be half of the number of the disk-like portions 20, as illustrated in FIG. 
9. In other words, each of the openings 75 can be twice as large as one of 
the disk-like portions 20. Further, a single opening 76 can be formed for 
a train of the plurality of the disk-like portions 20 to be formed at one 
time, as illustrated in FIG. 10. In the above embodiment, the five of the 
disk-like portions 20 are formed at one time. It is possible at one time 
to form four or less, or six or more of the disk-like portions 20. 
In the above embodiment, the continuous sheet 27 has a width associated 
with forming of only one of the disk-like portions 20. A plurality of the 
disk-like portions 20 are either formed and punched at one time in the 
longitudinal direction of the continuous sheet 27. However a wide 
continuous sheet 78 can be used as illustrated in FIG. 11. To form and 
punch a plurality of the disk-like portions 20 in a matrix form at one 
time, there are arranged a vacuum/air-pressure forming unit 79, a first 
punching unit 80, a second punching unit 81, and a disk withdrawing unit 
82. 
Another preferred apparatus 85 for producing a disk is described next. FIG. 
12 schematically illustrates the disk producing apparatus 85 inclusive of 
an index table 86. The index table 86 is rotatable in intermittent fashion 
in the counterclockwise direction. Eight (8) sheet holders 87 are secured 
to the index table 86 as a mask device. Around the index table 86 are 
arranged units of respective steps for producing the disks 17, in stations 
where each of the sheet holders 87 is stopped in the intermittent rotation 
of the index table 86. 
Those units are a sheet supply unit 89, a sheet heating unit 90, a 
vacuum/air-pressure forming unit 91, a sheet cooling unit 92, a first 
punching unit 93, a second punching unit 94, a third punching unit 95, and 
a sheet exit unit 96, arranged in the order listed. The sheet supply unit 
89 cuts a single sheet 88 of a predetermined size from the continuous 
sheet 27 wound as a roll, and supplies a closely positioned one of the 
sheet holders 87 with the sheet 88. The sheet heating unit 90 heats the 
sheet 88 supported in the one sheet holder 87. The forming unit 91 
subjects the sheet 88 to the vacuum/air-pressure forming, and forms five 
of the disk-like portions 20. The sheet cooling unit 92 cools the sheet 
88. The first punching unit 93 cuts the bearing hole 17a in the disk-like 
portions 20. The second punching unit 94 cuts the slots 23 in the 
disk-like portions 20. The third punching unit 95 cuts the contour of the 
disk-like portions 20 from the sheet 88 to form the disks 17. The sheet 
exit unit 96 remove the sheet 88 from the one sheet holder 87 after 
cutting away the disks 17. 
The one sheet holder 87, as illustrated in FIG. 13, is constituted by an 
upper mask plate 98 and a lower mask plate 99. The lower mask plate 99 has 
a receiving recess 100 and five (5) openings 101. The receiving recess 100 
receives the sheet 88. The openings 101 come through the bottom of the 
receiving recess 100, and respectively have a greater diameter than a 
diameter of the disks 17. The upper mask plate 98 has a pressing ridge 102 
and five (5) openings 103. The pressing ridge 102 is fitted in the 
receiving recess 100 to squeeze the sheet 88. The openings 103 come 
through the pressing ridge 102, and respectively have a greater diameter 
than a diameter of the disks 17. 
There are four guide shafts 106 mounted through the index table 86 and 
slidable vertically via slide bearings 105. The mask plates 98 and 99 
receives insertion of the guide shafts 106 and slidable vertically via 
slide bearings 107 and 108. 
Upper and lower ends 106a and 106b of the guide shafts 106 are respectively 
fixed on retaining plates 110 and 111, to keep adjacent ones of the guide 
shafts 106 positioned at a regular interval. Two rings or flanges 112 and 
113 are disposed on each of the guide shafts 106, and respectively below 
and above the index table 86. The flange 112 defines an upper limit of 
sliding the guide shafts 106. The flange 113 defines a lower limit of 
sliding the guide shafts 106. 
The lower mask plate 99 is disposed between the flange 113 and the index 
table 86. The upper mask plate 98 is disposed between the flange 113 and 
the retaining plate 110. There are recesses 115 formed in the lower mask 
plate 99 and located over the slide bearings 108, for receiving the flange 
113. A sufficient space can be made between the mask plates 98 and 99 for 
insertion of the sheet 88, by the virtue of the recesses 115. 
There is a spring 116 having greater biasing force, arranged between the 
lower mask plate 99 and the index table 86 and around each of the guide 
shafts 106. There is a spring 117 having smaller biasing force than the 
spring 116, arranged between the retaining plate 110 and the upper mask 
plate 98 and around each of the guide shafts 106. When not in use, the 
spring 116 raises the lower mask plate 99 so as to contact the flange 113 
on the lower mask plate 99 and contact the flange 112 on the index table 
86. At the same time, the spring 117 causes the upper mask plate 98 to 
contact on the lower mask plate 99. 
There is a shaft 119 which is disposed to extend from the retaining plate 
111, and comes downwards therefrom. A connector plate 120 is secured to a 
bottom end of the shaft 119. When the shaft 119 is pulled downwards via 
the connector plate 120, the guide shafts 106 are also pulled down. The 
flange 113 of the guide shafts 106 lower the lower mask plate 99 against 
the bias of the spring 116. 
There is a shaft 121 which is disposed to extend from the upper mask plate 
98, and comes upwards and through the retaining plate 110. A connector 
plate 122 is secured to a top end of the shaft 121. When the shaft 121 is 
pulled upwards via the connector plate 122, the upper mask plate 98 is 
raised against the bias of the spring 117. With the connector plates 120 
and 122 pulled away from one another, there takes place a space between 
the mask plates 98 and 99 to smooth the supply and exit of the sheet 88. 
The sheet supply unit 89 has a pair of solenoids 124 and 125 respectively 
arranged on the top and the bottom in stationary fashion. The solenoids 
124 and 125 have plungers 126 and 127, which are protruded when not 
energized, and retracted therein when energized. Tips of the plungers 126 
and 127 have respective two-bracketed connectors 128 and 129 for 
engagement. When the one sheet holder 87 is rotated to the sheet supply 
unit 89, the two-bracketed connectors 128 and 129 receive insertion of the 
connector plate 120 of the retaining plate 111 and the connector plate 122 
of the upper mask plate 98. 
When the solenoid 125 is energized, the plunger 127 is pulled to the inside 
of the solenoid 125. The two-bracketed connector 129 is engaged with the 
connector plate 120 to pull the guide shafts 106 downwards. The flange 113 
pulls the lower mask plate 99 down against the bias of the spring 116. A 
downstroke of the lower mask plate 99 is adjustable according to an extent 
of a projecting amount of an adjusting screw 131 on a bottom of the lower 
mask plate 99. In a similar manner, when the solenoid 124 is energized, 
the upper mask plate 98 is pulled up by the plunger 126 against the bias 
of the spring 117. Then the space between the mask plates 98 and 99 is 
widely formed as illustrated in FIG. 14. 
A retaining arm 133 retains the sheet 88 in the air suction. When the one 
sheet holder 87 is open, the retaining arm 133 with the sheet 88 is driven 
by an air cylinder or solenoid, and inserted between the mask plates 98 
and 99 of the sheet supply unit 89. Then the air suction of the retaining 
arm 133 is stopped. The sheet 88 is dropped into the receiving recess 100 
of the lower mask plate 99. 
A suction device 135, for example a vacuum pump device, is disposed under 
the lower mask plate 99, for sucking the sheet 88 through the openings 
101. The suction device 135 has a nozzle 136, which is inserted in the 
openings 101 when the lower mask plate 99 is pulled down. Even if the 
sheet 88 has a considerable curl, the sheet 88 can be reliably positioned 
in the receiving recess 100. While the suction device 135 is effecting the 
air suction, the solenoids 124 and 125 stop being energized. Then the mask 
plates 98 and 99 are pressed by the spring 117 and the spring 116. The 
sheet 88 is squeezed between the mask plates 98 and 99. With the one sheet 
holder 87 closed, there takes place a space between the one sheet holder 
87 and the suction device 135 as illustrated in FIG. 13. The index table 
86 becomes rotatable again without a problem. 
As illustrated in FIG. 15, the sheet heating unit 90 has a solenoid 138 
only on the bottom. The solenoid 138 operates to lower the one sheet 
holder 87, not to open the one sheet holder 87. When the solenoid 138 is 
energized and the connector plate 120 is pulled, the lower mask plate 99 
is lowered against the spring 116. The one sheet holder 87 is lowered 
while the sheet 88 is kept retained in the one sheet holder 87, as the 
upper mask plate 98 is biased downwards by the spring 117. 
In the sheet heating unit 90, a lower sheet heater 140 is disposed under 
the lower mask plate 99. The lower sheet heater 140 includes a heater head 
141 and a cartridge heater. The heater head 141 is formed of material with 
high heat conductivity, such as iron or aluminum. The cartridge heater is 
incorporated in the heater head 141. When the one sheet holder 87 is 
pulled down, the heater head 141 of the lower sheet heater 140 is inserted 
into the openings 101. There is an upper sheet heater 142 disposed above 
the upper mask plate 98. The upper sheet heater 142 is moved down by an 
air cylinder, a solenoid and the like not shown, to insert a heater head 
143 into the openings 103. In the sheet heating unit 90, portions of the 
sheet 88 externally emerging through the openings 101 and 103 are heated 
as hot as 150.degree. C. Only the portions of the sheet 88 to be formed in 
the vacuum/air-pressure forming are heated, so that the sheet 88 is not 
melted or stuck on the one sheet holder 87 in irrecoverable fashion. 
The temperature is measured near to the sheet 88. When the heating of the 
sheet 88 is finished, the upper sheet heater 142 is raised. The solenoid 
138 finishes being energized. The one sheet holder 87 is moved upwards by 
the spring 116. 
An inside of the upper mask plate 98 has a liquid passageway 145, through 
which hot liquid medium, such as water or specialty oil for applying heat, 
is circulated inside the upper mask plate 98. The liquid passageway 145 is 
disposed around the openings 103. The hot liquid medium is entered into an 
entrance pipe 146 of the liquid passageway 145, flows through the liquid 
passageway 145 to heat the one sheet holder 87 to the temperature 
10-50.degree. C. lower than a softening point of the sheet 88, and exited 
from an exit pipe 147 of the liquid passageway 145 to the outside. 
The pipes 146 and 147 are passed through a rotary joint 148 (See FIG. 12) 
disposed at the center of the index table 86, and connected to a liquid 
pump which is disposed under the index table 86 for the hot liquid medium. 
Under the index table 86 are arranged a liquid tank and a heater for 
heating the liquid medium, as well as the liquid pump. Note that a 
passageway 149, and pipes 150 and 151 associated with the lower mask plate 
99 are similar to those elements, and are not described further. 
In the forming unit 91, the one sheet holder 87 is pulled down in a manner 
similar to the sheet heating unit 90. As illustrated in FIG. 16, a female 
mold 153 is disposed under the lower mask plate 99. With the one sheet 
holder 87 pulled down, the female mold 153 is inserted in the openings 
101. There is a male mold 154 disposed above the upper mask plate 98. The 
male mold 154 is moved down by an air cylinder, a solenoid and the like 
not shown, and inserted into the openings 103. A sucking passageway 155 is 
formed to communicate through the female mold 153 for the air suction. A 
sucking passageway 156 is formed to communicate through the male mold 154 
for the air pressurization. At the same time as the descent of the one 
sheet holder 87 and before the descent of the male mold 154, the air 
suction starts being effected through the sucking passageway 155. The air 
pressurization starts being effected through the sucking passageway 156. 
The sheet 88 is tightly contacted on the female mold 153. The five (5) of 
the disk-like portions 20 are formed in the sheet 88 with high precision. 
Thus the portion of the sheet 88 masked in the one sheet holder 87 is 
heated to the temperature 10-50.degree. C. lower than its softening point, 
to avoid occurrence of wrinkles on the sheet 88. The sheet 88 is not 
deformed in unwanted fashion, as retained in the one sheet holder 87. 
After the vacuum/air-pressure forming, the sheet cooling unit 92 is adapted 
to cooling the sheet 88 and in advance of next unit for the punching. Note 
that it is possible to cool the sheet 88 in the forming unit 91, and to 
install a unit for withdrawing disks in place of the sheet cooling unit 
92. 
The first punching unit 93 is adapted to cutting the bearing hole 17a in 
the disk-like portions 20 formed on the sheet 88. A punch and a die are 
operated via the openings 101 and 103 respectively in the mask plates 98 
and 99. Scraps created by cutting the bearing hole 17a are dropped through 
the die to exit to the outside, in a manner similar to the former 
embodiment of FIGS. 1-11. 
The second punching unit 94 is adapted to cutting the slots 23 of an arc 
shape in the disk-like portions 20 formed on the sheet 88. In fashion 
similar to the first punching unit 93, a punch and a die are operated via 
the openings 101 and 103 respectively in the mask plates 98 and 99. Scraps 
created by cutting the slots 23 are dropped through the die to exit to the 
outside. 
The third punching unit 95 is adapted to cutting the contour of the 
disk-like portions 20 from the sheet 88. In fashion similar to the 
punching units 93 and 94, a punch and a die are operated. The disks 17 as 
cut out are dropped through the die, and contained in a disk container 
disposed under the die. This being so, the precision of the disks 17 as 
produced is heightened by precise positioning of the sheet holders 87 in 
the successive units, so that eccentricity between the forming and the 
punching is reduced. 
It is also possible to provide the third punching unit 95 with a push back 
device, so that the disks 17 after being punched away can be returned to 
the sheet 88 after the punching. For this structure, a disk withdrawing 
unit may be provided for withdrawing the disks 17 from the sheet 88. Also, 
it is alternatively possible that the bearing hole 17a, the slots 23 and 
the contour is cut by the first punching unit 93, and the punching units 
94 and 95 are eliminated. 
The sheet exit unit 96 is structurally similar to the sheet supply unit 89, 
and has two solenoids respectively arranged on the top and the bottom in 
stationary fashion, for opening a space between the mask plates 98 and 99. 
There is a retaining arm similar to the retaining arm 133 of the sheet 
supply unit 89. When the one sheet holder 87 is open, the retaining arm is 
driven by an air cylinder or solenoid, and inserted into the one sheet 
holder 87. The retaining arm takes up the sheet 88 from the receiving 
recess 100, retains it by the air suction, is moved out of the one sheet 
holder 87, and exit the sheet 88 from the one sheet holder 87 after 
punching of the disks 17. Note that the sheet exit unit 96 can have an air 
cylinder or hydraulic cylinder instead of the solenoid, for driving the 
one sheet holder 87. 
Operation of the above embodiment is described now. In FIG. 12, a starting 
command is entered into the disk producing apparatus 85, which starts 
intermittent rotation of the index table 86. At the same time as this, the 
upper sheet heater 142 and the lower sheet heater 140 of the sheet heating 
unit 90 are energized. The hot liquid medium, such as water or specialty 
oil for applying heat, starts flowing through the liquid passageways 145 
and 149 in the mask plates 98 and 99. The one sheet holder 87 is heated to 
the temperature 10-50.degree. C. lower than the softening point of the 
sheet 88. 
The index table 86 is stopped, to locate the one of the one sheet holder 87 
in the sheet supply unit 89 as illustrated in FIG. 13. The connector plate 
122 of the upper mask plate 98 and the connector plate 120 of the 
retaining plate 111 are inserted respectively in the two-bracketed 
connectors 128 and 129 of the solenoids 124 and 125. After insertion of 
the connector plate 122 and the connector plate 120 into the two-bracketed 
connectors 128 and 129, the solenoids 124 and 125 are energized. 
With the solenoids 124 and 125 energized, the plungers 126 and 127 are 
withdrawn into the solenoids 124 and 125. The two-bracketed connectors 128 
and 129 pull the connector plate 122 and the connector plate 120 
vertically. The guide shafts 106 are pulled down by the retaining plate 
111. The lower mask plate 99 is lowered by the flange 113 against the 
spring 116. The upper mask plate 98 is pulled up against the spring 117, 
to widen the space between the mask plates 98 and 99 as illustrated in 
FIG. 14. 
The retaining arm 133 is driven by the air cylinder or solenoid and 
inserted between the mask plates 98 and 99, while retaining the sheet 88 
in the air suction after the cutting from the continuous sheet 27. Then 
the retaining arm 133 is released from the air suction, to drop the sheet 
88 to the receiving recess 100 in the lower mask plate 99. The air suction 
is being effected through the nozzle 136, which is lowered into the 
openings 101 in lowering of the lower mask plate 99. Even with the curl, 
the sheet 88 is reliably contained in the receiving recess 100. 
When the sheet 88 finishes being supplied, the retaining arm 133 is 
retracted from the mask plates 98 and 99. The solenoids 124 and 125 stop 
being energized. The mask plates 98 and 99 are pressed by the spring 117 
and the spring 116, to come to each other. The pressing ridge 102 of the 
upper mask plate 98 is received in the receiving recess 100 of the lower 
mask plate 99. The sheet 88 is squeezed between the mask plates 98 and 99. 
The suction device 135 still effects air suction until the one sheet 
holder 87 is closed. 
When the one sheet holder 87 is supplied with the sheet 88, the index table 
86 is rotated again intermittently, to convey the one sheet holder 87 to 
the sheet heating unit 90. As illustrated in FIG. 15, the sheet heating 
unit 90 has the solenoid 138 under the sheet holders 87. A two-bracketed 
connector 138a pulls the connector plate 120 of the retaining plate 111, 
to slide down the guide shafts 106. The lower mask plate 99 is pulled by 
the flange 113 of the guide shafts 106, and lowered against the spring 
116. The upper mask plate 98 follows the descent of the lower mask plate 
99 under the bias of the spring 117. The sheet 88 still remains retained. 
The one sheet holder 87 is pulled down. The heater head 141 of the lower 
sheet heater 140 is inserted into the openings 101, to heat the bottom of 
the sheet 88. After the descent of the one sheet holder 87, the upper 
sheet heater 142 is lowered from the upper mask plate 98 by the air 
cylinder, the solenoid and the like. The heater head 143 is inserted into 
the openings 103. The portions of the sheet 88 emerging through the 
openings 101 and 103 are heated as hot as 150.degree. C. With the hot 
liquid medium such as water or specialty oil circulated through the liquid 
passageways 145 and 149 in the mask plates 98 and 99, the portion of the 
sheet 88 masked in contact with the one sheet holder 87 and excluded from 
the vacuum/air-pressure forming are heated to the temperature 
10-50.degree. C. lower than the softening point of the sheet 88. 
Heating of the sheet 88 is finished when the temperature near to the sheet 
88 comes up to the predetermined value. The upper sheet heater 142 is 
raised first. Then the solenoid 138 finishes being energized. The one 
sheet holder 87 is raised by the bias of the spring 116. It is also 
possible to measure preheating time experimentally for heating the sheet 
88 with the heaters, and to finish preheating the sheet 88 when the 
measured time lapses. 
After heating the sheet 88, the index table 86 is rotated again, to convey 
the one sheet holder 87 to the forming unit 91. The forming unit 91 has 
the single solenoid under the sheet holders 87, in a manner similar to the 
sheet heating unit 90. The one sheet holder 87 is lowered again. As 
illustrated in FIG. 16, the female mold 153 is under the lower mask plate 
99. With the one sheet holder 87 pulled down, the female mold 153 is 
inserted in the openings 101. After the descent of the one sheet holder 
87, the male mold 154 is moved down lower than the upper mask plate 98 by 
the air cylinder, the solenoid and the like, and inserted into the 
openings 103. 
When the male mold 154 is lowered, the air suction is effected through the 
sucking passageway 155 in the female mold 153, to keep the sheet 88 in 
tight contact with the female mold 153 after the heating and softening. 
The air pressurization is effected through the male mold 154 to press the 
sheet 88 against the female mold 153. Then the disk-like portions 20 are 
formed in the sheet 88 with high precision. No wrinkles occur, as the 
portion of the sheet 88 in the one sheet holder 87 has been heated. 
After the forming of the disk-like portions 20, the male mold 154 is 
raised, before the one sheet holder 87 is raised. The index table 86 is 
rotted again. As illustrated in FIG. 12, the one sheet holder 87 is 
conveyed to the lower, where the sheet 88 is cooled in advance of next 
unit for the punching. For the cooling, the sheet 88 can be left to stand 
as it is for a predetermined duration. Or air may be caused to blow the 
sheet 88 to cool the same forcibly. 
After cooling of the sheet 88, the index table 86 is rotated again. The one 
sheet holder 87 is conveyed to the first punching unit 93, where the 
bearing hole 17a is cut in the disk-like portions 20 on the sheet 88 by 
the punch and the die. The scraps created by cutting the bearing hole 17a 
are dropped through the die to exit to the outside. 
The sheet 88 in which the bearing hole 17a is formed is conveyed to the 
second punching unit 94 by rotation of the index table 86. In the second 
punching unit 94, the slots 23 of the arc shape is cut in the disk-like 
portions 20 on the sheet 88 by the punch and the die. In the fashion 
similar to the first punching unit 93, the scraps created by cutting the 
slots 23 are dropped through the die to exit to the outside. 
The sheet 88 worked in the second punching unit 94 is conveyed to the third 
punching unit 95 by rotation of the index table 86. In the third punching 
unit 95, the contour of the disk-like portions 20 is cut in the sheet 88. 
The disks 17 are dropped into the disk container which receives the disks 
17. The disk container, when filled with a great number of the disks 17, 
is conveyed to a line for the spool 5. In place are the disk container as 
filled, a new container are positioned in the third punching unit 95. In 
repetition of those steps, the disks 17 is produced in successive fashion. 
In the above embodiment, the hot liquid medium such as water or specialty 
oil applies heat to the sheet holders 87. Electrically heated wires or a 
feeder slip ring is also usable. Note that, if a product to be formed by 
the vacuum/air-pressure forming has an undercut, it is preferable to 
provide the female mold 153 with a push-out mechanism for pushing the 
sheet 88 up. 
The number of the openings 101 and 103 for defining the heated range of the 
sheet 88 is set equal to the number of the disk-like portions 20. However 
it is possible that each of openings is twice as great as one of the 
disk-like portions 20, similarly to the openings 75 in FIG. 9. Further, a 
pair of single openings can be formed for a train of the plurality of the 
disk-like portions 20 to be formed at one time, similarly to the single 
opening 76 in FIG. 10. 
In the above embodiment, the five (5) of the disks 17 are formed at one 
time. Of course the present invention is applicable to forming of a 
greater number of the disks 17 at one time in two or three lines as a 
matrix form, as illustrated in FIG. 17 with a sheet holder 160 as mask 
device. It is also possible in FIG. 18 to dispose a ring-like projection 
161b around a bottom of an opening 161a in an upper mask plate 161, for 
contact with a sheet 162 as squeezed. The size of the opening 161a is set 
considerably greater than the disks 17 in view of preventing the ring-like 
projection 161b from influencing the disk-like portions 20. 
It is further possible in the forming unit 91 to form a positioning portion 
at the center of each of the disk-like portions 20 in a size smaller than 
the bearing hole 17a. In the first punching unit 93, the bearing hole 17a 
can be cut by utilizing the positioning portion. This raises concentricity 
between the disk-like portions 20 and the bearing hole 17a. It is also 
possible to set up a slit punching unit instead of the sheet cooling unit 
92. The slit punching unit can be adapted to cutting bend slits in the 
periphery of the disk-like portions 20. The disk-like portions 20 can be 
rendered movable from the sheet 88 in minute fashion in any direction, 
without removal from the sheet 88. 
Still another preferred disk producing apparatus is described now. As 
illustrated in FIG. 19, units for the disk production are rectilinearly 
arranged in similar fashion to the first preferred embodiment. A sheet 
supply unit 165 is substantially the same as the sheet supply unit 28 of 
FIG. 3. A sheet winding unit 166 is substantially the same as the sheet 
winding unit 33. Those are not described any further in detail. 
The sheet supply unit 165 supplies a sheet heating unit 167 with a 
continuous sheet 171 (See FIG. 20) of thermoplastic resin. The sheet 
heating unit 167, as illustrated in FIG. 20, has a mask device 170 
including an upper mask plate 168 and a lower mask plate 169. The 
continuous sheet 171 is conveyed between the mask plates 168 and 169. The 
upper mask plate 168 has five greater openings 168a larger than the disks 
17, and two smaller openings 168b smaller than the greater openings 168a. 
Similarly the lower mask plate 169 has five greater openings 169a and two 
smaller openings 169b. The smaller openings 168b and 169b are adapted to 
heating the continuous sheet 171 at portions formed to be retainable 
portions used in conveyance of the continuous sheet 171. 
The upper mask plate 168 is secured to guide shafts 173 erected on the 
lower mask plate 169, and is vertically movable along the guide shafts 173 
by means of hydraulic cylinders, air cylinders, cams, and the like. The 
upper mask plate 168, when lowered, squeezes the continuous sheet 171 
between it and the lower mask plate 169, and prevents the continuous sheet 
171 from being deformed. As is not shown, the inside of the mask plates 
168 and 169 respectively has a liquid passageway, through which hot liquid 
medium, such as water or specialty oil for applying heat, is circulated, 
in the same manner as the former embodiments. The hot liquid medium heats 
the continuous sheet 171 to the temperature 10-50.degree. C. lower than a 
softening point of the continuous sheet 171. 
As illustrated in FIG. 21, a upper sheet heater 175 and a lower sheet 
heater 176 are disposed so that the mask device 170 lies between them. A 
block 177 incorporates a cartridge heater 175a. A block 178 incorporates a 
cartridge heater 176a. The block 177 and 178 are respectively formed of 
material with high heat conductivity, such as iron or aluminum. The 
cartridge heaters 175a and 176a are controlled so that the blocks 177 and 
178 have a surface temperature of 400.+-.5.degree. C., to heat the 
portions of the continuous sheet 171 emerging through the greater openings 
168a and 169a as hot as 150.degree. C. Heating of the continuous sheet 171 
is finished when the temperature near to the continuous sheet 171 as 
measured comes up to 150.degree. C. as predetermined. It is also possible 
to measure preheating time experimentally for heating the continuous sheet 
171 with the heaters, and to finish preheating the continuous sheet 171 
and convey the continuous sheet 171 when the measured time lapses. 
There are regulating recesses 177a and 178a in the blocks 177 and 178 in 
positions confronted respectively with the greater openings 168a and 169a 
in the mask plates 168 and 169. If it were not for the regulating recesses 
177a and 178a, it would be likely that portions of the continuous sheet 
171 emerging through the greater openings 168a and 169a would have 
unevenness in temperature: the center of each portion would be hotter than 
the periphery. There would occur distortion in disks. However the use of 
the regulating recesses 177a and 178a is advantageous, as their distance 
to the continuous sheet 171 is increased from each periphery of the 
portions to be heated toward each center of the portions. 
The continuous sheet 171 heated by the sheet heating unit 167 are conveyed 
to a forming unit 180, where the heated portions of the continuous sheet 
171 is tightly contacted on a mold set by the vacuum/air-pressure forming 
the same as the former embodiments, to form the disk-like portions 20 in 
FIGS. 22A and 22B with high precision. The continuous sheet 171 is not 
melted, stuck on the sheet holders 87, or torn in irrecoverable fashion. 
The portion of the continuous sheet 171 other than the portions for the 
disk-like portions 20 is also heated by the mask plates 168 and 169 and 
swellable sufficiently, so that no wrinkles occurs in the continuous sheet 
171. 
A positioning portion 181 and a retainable portion 182 are formed by the 
vacuum/air-pressure forming. The positioning portion 181 is located at the 
center of the disk-like portions 20 at a radius smaller than the bearing 
hole 17a. The retainable portion 182 is located in each of positions 
heated through the smaller openings 168b and 169b in the mask plates 168 
and 169. The positioning portion 181 and the retainable portion 182 have 
respective conical shapes inclusive of conical faces 181b and 182b in 
inclination and bottom faces 181a and 182a. The bottom faces 181a and 182a 
are substantially flat. The positioning portion 181 and the retainable 
portion 182 respectively receive insertion of a positioning pin and a 
conveying pin. In this insertion, the conical faces 181b and 182b operate 
for guiding the pins into the positioning and retainable portions 181 and 
182. 
FIG. 22C illustrates construction of the forming unit 180. A female mold 
plate 179 is mounted on the stationary support 43, and includes five (5) 
disk-molding female molds 179a aligned in the conveying direction of the 
continuous sheet 171. Five (5) positioner-molding female molds 179b are 
also aligned, and respectively located at the centers of the disk-molding 
female molds 179a. Two (2) retainer-molding female molds 179c are arranged 
in the width direction of the continuous sheet 171. A male mold plate 184 
is mounted on the movable support 45, and includes five (5) disk-molding 
male molds 184a, five (5) positioner-molding male molds 184b, and two (2) 
retainer-molding male molds 184c. Each combination of the 
positioner-molding female molds 179b and the positioner-molding male molds 
184b forms the positioning portion 181. Each combination of the 
retainer-molding female molds 179c and the retainer-molding male molds 
184c forms the retainable portion 182. 
The continuous sheet 171 is conveyed by a sheet conveyor 183 utilizing the 
retainable portion 182. In the sheet conveyor 183, a receiving recess 185a 
is formed in a top of a sheet clamp 185. As illustrated in FIG. 23, the 
retainable portion 182 is inserted into the receiving recess 185a in the 
course of conveying the continuous sheet 171. The receiving recess 185a is 
open in a direction in reverse to conveyance of the continuous sheet 171, 
of which conveyance inevitably causes the receiving recess 185a to receive 
the retainable portion 182. 
The sheet clamp 185 is mounted on a guide shaft 186 disposed in parallel 
with a conveying path of the continuous sheet 171. Slide bearings (not 
shown) render the sheet clamp 185 slidable along the guide shaft 186. The 
sheet clamp 185 is connected to a belt 188, which is disposed on the 
periphery of pulleys 187a and 187b under the guide shaft 186. When the 
pulley 187a is rotated by a motor 189, the sheet clamp 185 is slid by the 
guide shaft 186. 
Above the sheet clamp 185 is located a conveying pin 190, which can be slid 
by driving a solenoid 191, between an upwards retracted position and a 
downwards protruded position. When protruded downwards, the conveying pin 
190 is inserted in the retainable portion 182 at the receiving recess 
185a. An inclined face 190a of the conveying pin 190 is contacted on the 
conical face 182b of the retainable portion 182, to position the 
retainable portion 182, which is clamped between the conveying pin 190 and 
the receiving recess 185a at the same time. The conveying pin 190, while 
the retainable portion 182 is clamped, is moved to a position indicated by 
the phantom line, to convey the continuous sheet 171 in intermittent 
fashion. 
In a position downstream from the sheet clamp 185, a sheet retaining 
mechanism 192 is disposed for pressing the continuous sheet 171. The sheet 
retaining mechanism 192 includes a pressing pin 194 and a table 195. The 
pressing pin 194 is movable with a solenoid 193. The table 195 is located 
under the continuous sheet 171. After conveyance of the continuous sheet 
171, the pressing pin 194 is protruded by the solenoid 193, to squeeze the 
continuous sheet 171 between it and the table 195 to keep the continuous 
sheet 171 immovably after the stop. A rubber head 194a is fixed on the 
bottom of the pressing pin 194, to retain the continuous sheet 171 
reliably and avoid scratching the continuous sheet 171. 
A dancer roller 196 is disposed past the sheet retaining mechanism 192, for 
absorbing looseness of the continuous sheet 171 while applying sufficient 
tension thereto. Note that the conveying pin 190 and the pressing pin 194 
may be protruded by use of air cylinders, cams or the like, instead of the 
solenoids 191 and 193. 
After the forming unit 180 forms the disk-like portions 20, the positioning 
portion 181 and the retainable portion 182, the continuous sheet 171 is 
conveyed to a slit punching unit 198. In the slit punching unit 198, a 
punch and a die, known in the art, form two kinds of bend slits 199a and 
199b in arcuate shapes in the periphery of the disk-like portions 20 as 
illustrated in FIGS. 24A and 24B. The disk-like portions 20 remain 
connected to the continuous sheet 171 via bridge portions 199c defined by 
the bend slits 199a and 199b. The disk-like portions 20 are rendered 
movable from the continuous sheet 171 in minute fashion in any direction, 
without removal from the continuous sheet 171. Scraps created by cutting 
the bend slits 199a and 199b are dropped through the die to exit to the 
outside. 
After the slit punching, the continuous sheet 171 is conveyed by the sheet 
conveyor 183 to a first punching unit 200. As illustrated in FIG. 25A, the 
first punching unit 200 has a punch/die set 201 for cutting the bearing 
hole 17a and the slots 23 in the disk-like portions 20 at the same time. 
The punch/die set 201 includes a punch 202 above the continuous sheet 171 
and a die 203 under the continuous sheet 171. The center of the punch 202 
has a positioning pin 204, to be inserted in the positioning portion 181 
to position the disk-like portions 20. 
A bottom of the positioning pin 204 is protruded downwards further than the 
punch 202. As illustrated in FIG. 25B, the positioning pin 204 is first 
received in the positioning portion 181 when the punch 202 is lowered, to 
position the disk-like portions 20. Afterwards the bearing hole 17a and 
the slots 23 are cut. The bottom of the positioning pin 204 is provided 
with a conical face 204a in inclination associated with the conical face 
181b of the positioning portion 181. The contact of the conical face 204a 
with the conical face 181b reliably guides the positioning portion 181. 
With the minute mobility of the disk-like portions 20 having the bend 
slits 199a and 199b, concentricity in treating the disk-like portions 20 
between the vacuum/air-pressure forming and the punching is kept adequate. 
Scraps 205 formed by cutting the bearing hole 17a and the slots 23 are 
dropped through the die 203 to exit to the outside. 
The continuous sheet 171 having the bearing hole 17a and the slots 23 is 
conveyed to a second punching unit 206. As illustrated in FIG. 26A, the 
second punching unit 206 has a punch/die set 207 for punching the contour 
of the disk-like portions 20 to cut out the disks 17. The punch/die set 
207 includes a punch 208 above the continuous sheet 171 and a die 209 
under the continuous sheet 171. The center of the punch 208 has a 
positioning pin 210, to be inserted in the bearing hole 17a to position 
the disk-like portions 20. 
A bottom of the positioning pin 210 is protruded downwards further than the 
punch 208. As illustrated in FIG. 26B, the positioning pin 210 is first 
received in the bearing hole 17a when the punch 208 is lowered, to 
position the disk-like portions 20. Afterwards the disk contour is 
punched. When the positioning pin 210 is inserted in the bearing hole 17a, 
the disk-like portions 20 are minutely moved by the virtue of the bend 
slits 199a and 199b, so that concentricity in treating the disk-like 
portions 20 between the vacuum/air-pressure forming and the punching is 
kept adequate. 
The disks 17 are dropped under the die 209, and collected in a disk 
container. Note that the second punching unit 206 can be provided with a 
push back device, so that the disks 17 after being punched away can be 
returned to the continuous sheet 171 after the punching. For this 
structure, a disk withdrawing unit can be added downstream from the second 
punching unit 206 for withdrawing the disks 17 from the continuous sheet 
171. 
Referring to FIG. 19, in operation, an operating command is entered into 
the disk producing apparatus, which starts conveyance of the continuous 
sheet 171 from the sheet supply unit 165 to the sheet heating unit 167. In 
the sheet heating unit 167 as illustrated in FIGS. 20 and 21, the upper 
mask plate 168 of the mask device 170 is driven by the hydraulic 
cylinders, the air cylinders, the cams, and the like, is lowered along the 
guide shafts 173. The continuous sheet 171 is squeezed between the mask 
plates 168 and 169, and retained. 
The portions of the continuous sheet 171 emerging through the greater 
openings 168a and 169a and the smaller openings 168b and 169b are heated 
by the sheet heaters 175 and 176 having the surface temperature of nearly 
400.degree. C. In the blocks 177 and 178, the distance from the regulating 
recesses 177a and 178a to the continuous sheet 171 is increased from each 
periphery of the portions to be heated toward each center of the portions. 
The center of each portion does not become any hotter than the periphery. 
With the sheet temperature regulated evenly, no distortion occurs in the 
disks. The continuous sheet 171 is heated as hot as 150.degree. C. The 
mask plates 168 and 169 are being heated by the hot liquid medium, such as 
water or specialty oil, so that the masked portion of the continuous sheet 
171 is heated to the temperature 10-50.degree. C. lower than the softening 
point of the continuous sheet 171. 
The continuous sheet 171 heated in the sheet heating unit 167 is conveyed 
to the forming unit 180, where heated portions of the continuous sheet 171 
are contacted on a mold by the vacuum and/or the air-pressure, and forms 
the disk-like portions 20, the positioning portion 181 and the retainable 
portion 182 with high precision as illustrated in FIGS. 22A and 22B. The 
portions of the continuous sheet 171 required for the forming have been 
heated to the softening point. The other portion is heated 10-50.degree. 
C. lower than the softening point, so that no wrinkles or breakage occurs 
in the continuous sheet 171. 
In FIG. 23, the retainable portion 182 is inserted into the receiving 
recess 185a while the continuous sheet 171 is conveyed. The solenoid 191 
causes the conveying pin 190 to extend downwards, and to enter the 
retainable portion 182. The inclined face 190a of the conveying pin 190 is 
contacted on the conical face 182b of the retainable portion 182, to 
position the retainable portion 182. The conveying pin 190 and the 
receiving recess 185a clamps the retainable portion 182. 
When the retainable portion 182 is retained on the sheet clamp 185, the 
motor 189 is driven, to rotate the pulley 187a in the clockwise direction. 
The sheet clamp 185 is moved along the guide shaft 186 to the right as 
viewed in the drawing, with the continuous sheet 171 retained on the 
retainable portion 182. Once the sheet clamp 185 comes to the position 
indicated by the phantom lines, the sheet clamp 185 is stopped. The 
pressing pin 194 of the sheet retaining mechanism 192 is protruded by the 
solenoid 193 downwards, and squeezes the continuous sheet 171 between the 
rubber head 194a and the table 195, to hold the continuous sheet 171 as 
stopped. 
The continuous sheet 171 provided with the disk-like portions 20, the 
positioning portion 181 and the retainable portion 182 is conveyed from 
the forming unit 180 to the slit punching unit 198, where the punch and 
the die form the bend slits 199a and 199b for the disk-like portions 20 as 
illustrated in FIGS. 24A and 24B. The scraps from the bend slits 199a and 
199b are dropped through the die to exit. 
The continuous sheet 171 after the slit punching is conveyed to the first 
punching unit 200 by the sheet conveyor 183. In the first punching unit 
200, as illustrated in FIGS. 25A and 25B, the punch 202 is lowered by the 
hydraulic cylinders, the air cylinders, the cams, and the like. The 
positioning pin 204 is first inserted in the positioning portion 181. The 
contact of the conical face 204a with the conical face 181b guides the 
positioning portion 181. The disk-like portions 20 are positioned in 
well-centered fashion adjusted through the bridge portions 199c. 
The punch 202 is further lowered, and cooperates with the die 203 to cut 
the bearing hole 17a and the slots 23 in the disk-like portions 20. The 
positioning of the positioning portion 181 with the positioning pin 204 is 
effective in raising concentricity between the forming of the ring-like 
lip 17b and the cutting of the bearing hole 17a and the slots 23. The 
scraps 205 created from the bearing hole 17a and the slots 23 are dropped 
through the die to exit. 
The continuous sheet 171 in which the bearing hole 17a and the slots 23 are 
formed is conveyed to the second punching unit 206, where the punch 208 is 
lowered by the hydraulic cylinders, the air cylinders, the cams, and the 
like, as illustrated in FIGS. 26A and 26B. The positioning pin 210 is 
first inserted in the bearing hole 17a. The disk-like portions 20 are 
positioned in well-centered fashion adjusted through the bridge portions 
199c. 
The punch 208 is further lowered, and cooperates with the die 209 to cut 
the contour of the disk-like portions 20 to punch out the disks 17. The 
positioning of the bearing hole 17a with the positioning pin 210 is 
effective in raising concentricity between the disk contour and the 
bearing hole 17a. The disks 17 are dropped under the die 209, collected in 
the disk container, and conveyed to a line for assemblage of the spool 5. 
In the above, the retainable portion and the positioning portion have 
respective recesses in which the pins are inserted for the retention and 
positioning. It is instead possible that a retainable portion and a 
positioning portion have respective projections, which may be retained and 
positioned by being inserted in respective recesses formed in a retaining 
device and a positioning device. Furthermore, it is possible not to form 
any additional positioning portion, but to use the ring-like lip of the 
disk-like portion as positioning portion, to be fitted on a positioning 
device shaped in association therewith. 
In any of the above embodiments, only the disks 17 are produced. The disks 
16 are produced separately from the disks 17. However the present 
invention is applicable for a disk producing apparatus in which the disks 
16 and 17 are produced from the same continuous sheet at the same time. 
The embodiment is described as a variant of the foregoing embodiment. In 
FIG. 27, a continuous sheet 215 has a great width, and subjected to the 
vacuum/air-pressure forming to form 10 of the disk-like portions 20 in 
2.times.5 matrix. The arrow indicates a direction of conveyance. To 
preheat the continuous sheet 215 before the forming, a mask plate having 
10 openings is used. Positioning portions 216 and retaining portions 217 
are formed at the same time as the disk-like portions 20. In a slit 
punching unit, as illustrated in FIG. 28, bend slits 218 and 219 in 
arcuate shapes are formed around the disk-like portions 20. All of the 
disk-like portions 20 have a common shape. 
In FIG. 29, the disk-like portions 20 are arranged in first and second 
lines. In the first punching unit, the bearing hole 17a and the slots 23 
are cut in disk-like portions of the first line of the disk-like portions 
20. The bearing hole 16a is cut in disk-like portions of the second line. 
In the second punching unit, the contour of all the disk-like portions 20 
is cut, so that the disks 16 and 17 are produced. Note that, if the disks 
16 and 17 as cut out are mixed up, they must be separated, subsequently 
prior to the assembly of the spool 5. It is preferred that there are two 
separate exit stations respectively associated with the disks 16 and 17 as 
receptacles of the die. 
In the above, the single sheet heater is used for heating the plural 
portions to be the disk-like portions. However it is likely that there is 
unevenness in temperature between positions on the sheet heater. FIG. 30 
illustrates an embodiment to solve this problem: plural sheet heaters 221 
are disposed in positions associated with respective openings 220 in a 
mask plate, and individually controlled in temperature. This is effective 
in regularizing quality of disks. 
In the above embodiments, each sheet heater includes the metal block and 
the cartridge heater incorporated in it. Instead, near infrared ray 
heaters, such as halogen lamp heaters, may be used. 
Each set of a punch and a die used in the slit punching unit, the first 
punching unit and the second punching unit means at the a faster rate the 
greater the number of the portions punched at the same time, and is costly 
when replaced by a new set. The present invention is applicable in a disk 
producing apparatus in which six disk-like portions are formed at one 
time, and then two or three of the disk-like portions are punched at one 
time. This can reduce the speed of the means of the sets of a punch and a 
die, and thus reduce the expenses for disk production. 
In any of the above embodiments, the sheet is heated sufficiently at one 
time. Alternatively the sheet can be heated at a plurality of times 
successively, in view of evenness and high performance in the heating. 
In the mold, the air passageway for air suction is formed. It is possible 
to eliminate the air passageway, and to form the mold from metal or 
ceramics having air permeability, so as to suck a sheet in regular fashion 
to regularizing quality of disks. 
To inspect disks as produced, the disks must be aligned in conventional 
techniques. However the apparatus of the present invention makes it 
possible to inspect the disks before punching of their contour: after the 
punching of the hole and the openings, the disk-like portions can be 
inspected by means of image recognition as to their contour shape and 
opened positions. This makes it unnecessary to align the disk as produced, 
and can raise efficiency in production. 
Although the present invention has been fully described by way of the 
preferred embodiments thereof with reference to the accompanying drawings, 
various changes and modifications will be apparent to those having skill 
in this field. Therefore, unless otherwise these changes and modifications 
depart from the scope of the present invention, they should be construed 
as included therein.