GB2040264A - Tape reel for video cassette - Google Patents
Tape reel for video cassette Download PDFInfo
- Publication number
- GB2040264A GB2040264A GB7944001A GB7944001A GB2040264A GB 2040264 A GB2040264 A GB 2040264A GB 7944001 A GB7944001 A GB 7944001A GB 7944001 A GB7944001 A GB 7944001A GB 2040264 A GB2040264 A GB 2040264A
- Authority
- GB
- United Kingdom
- Prior art keywords
- hub
- tape reel
- cylindrical wall
- flange
- tape
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000465 moulding Methods 0.000 claims abstract description 13
- 229920003002 synthetic resin Polymers 0.000 claims abstract description 10
- 239000000057 synthetic resin Substances 0.000 claims abstract description 10
- 238000002347 injection Methods 0.000 claims description 4
- 239000007924 injection Substances 0.000 claims description 4
- 238000003466 welding Methods 0.000 claims description 4
- 230000002093 peripheral effect Effects 0.000 claims 1
- 239000000463 material Substances 0.000 abstract description 6
- 238000000034 method Methods 0.000 abstract description 6
- 230000007547 defect Effects 0.000 abstract description 4
- 238000001746 injection moulding Methods 0.000 abstract description 3
- 238000009826 distribution Methods 0.000 description 4
- 238000010276 construction Methods 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- 235000013382 Morus laevigata Nutrition 0.000 description 1
- 244000278455 Morus laevigata Species 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000035755 proliferation Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B23/00—Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture
- G11B23/02—Containers; Storing means both adapted to cooperate with the recording or reproducing means
- G11B23/037—Single reels or spools
Landscapes
- Storage Of Web-Like Or Filamentary Materials (AREA)
Abstract
A tape reel comprising a pair of flanges and a hub integrally moulded with one of the flanges is provided with axially extending grooves 11 on the back of ribs 6 which project into the interior cavity 5 of the hub. The provision of these grooves makes the thickness of all of tape reel members uniform so that in the process of injection moulding the tape reel, moulding defects which might otherwise arise due to irregularities in the flow of the synthetic resin material from which the tape reel is made are prevented. <IMAGE>
Description
SPECIFICATION
Tape reel for video cassette
This invention relates to a tape reel of high dimensional precision for use in a video casette.
The recent proliferation of video tape recorders has led to large scale production of video cassettes of the type having video and sound recording magnetic tape contained between two cassette halves. A concurrent trend toward designing recorders capable of giving increased playing time for the length of tape has been accompanied by demands for higher image reproduction quality. The quality of the image reproduced by a video recorder depends not only on the performance of the magnetic tape itself but also, to a considerable extent, on the dimensional precision of the cassette halves and the tape reels on which the magnetic tape is wound.
Although tape reels come in a variety of sizes each matched to the reproduction system used by the particular manufacturer and the total reproduction time of the tape wound thereon, it is safe to say that all are molded of plastic and are of generally the same structure.
Specifically, the tape reels contained between the two halves of the cassette are typically constituted of a pair of flanges and a hub onto which the tape is wound and, for the sake of achieving optimum efficiency in fabrication, one of the flanges and the hub are integrally molded and, at the time of assembly of the cassette the other flange is bonded to the remaining free end of the hub. The hub has a centre cavity provided with engaging ribs for receiving and engaging with the spindle of the video tape recorder. In reproduction of the video images recorded on the magnetic tape wound onto the hub, anything less than perfect engagement between the hub and the spindle of the video tape recorder will be a cause of wow/flutter.The travel of the tape is also adversely affected by variations in the thickness of the integrally moulded hub and flange and by any sink marks that may occur at the border between the flange and the hub. Such variations and sink marks are fairly apt to occur in view of the fact that, in the generally adopted moulding method, the synthetic resin for the flange is passed through the region destined to become the hub.
The main object of the present invention is to provide a tape reel of high dimensional precision for a video tape cassette which is free from misformation of the ribs which engage the spindle of the video tape recorder, has highly uniform strength distribution characteristics, and gives consideration to the moulding of its integrally formed parts, such as the hub and a flange, so as to avoid defects in overall structure and dimensional precision.
According to the present invention, a tape reel for video cassette comprises a pair of flanges and a hub moulded integrally with one of the pair of flanges and connected to the other of the pair of flanges, which hub is comprised of an exterior cylindrical wall for receiving wound tape on its outer surface and an interior cylindrical wall having an internal cylindrical cavity opening through the integral flange for receiving the spindle of a video tape recorder therein, the interior cylindrical wall being provided on its inner surface with a plurality of regularly spaced ribs projecting radially inward and extending axially of the interior cylindrical wall for engaging with the spindle, further comprising axially extending grooves provided in the back of the interior cylindrical wall at positions behind the ribs.
By the provision of the grooves, it is possible for the thickness of the interior cylindrical wall to be made uniform throughout.
As the interior cylindrical wall of the hub having the ribs is moulded in a uniform thickness throughout, the synthetic resin injected in the injection moulding process undergoes uniform internal shrinkage during cooling. As a consequence it is easily possible to take this shrinkage into account in the designing of the hub to obtain a final product with high dimensional accuracy. Also, the fact that the ribs are of uniform thickness means that all portions of the hub can be made of uniform thickness so that when the hub section serves as a runner through which the synthetic resin material passes to reach the mould cavity for the integrally moulded flange, the rate of flow of the resin is uniform at all portions of the hub.Thus, the synthetic resin can be injected at a uniform rate of flow into the whole of the wide, but thin, flange cavity so as to obtain uniform resin distribution. As a result, the flange is free from local irregularities which might otherwise result from deformation caused by uneven hardening of the resin. This further contributes to the dimensional precision of the reel.
Other objects and features of the present invention will be clear from the following detailed description made with reference to the accompanying drawings, in which:
Figure 1 is a side view of one example of a conventional tape reel for a video cassette.
Figure 2 is a magnified, partially cut-away, vertical cross-sectional view taken along line Il-Il in Figure 1;
Figure 3 is a partially cut-away, transverse crosssectional view taken along the line Ill-Ill in Figure 2;
Figure 4 is a transverse cross-sectional view of the hub of one embodiment of the tape reel for video cassette according to the present invention.
Figure 5and Figure 6are a plan view and a bottom view of the embodiment shown in Figure 4.
Figures 1 through 3 show the main drive section, namely the tape reel onto which the tape is wound, of the type of casette now in general use. In the complete video cassette, this tape reel is housed between two cassette halves and has the magnetic video recording tape wound thereon. As the rotating velocity of the tape reel has an effect on the quality of the video image reproduced by the video tape recorder, it is required to have high dimensional precision.
Conventional tape reels have a pair of flanges 1, 1 connected to a central hub 2. One of the flanges is molded integrally with the hub and the other is molded separately and then is attached to the remaining free end of the hub by ultrasonic welding or the like. The tape is, of course, wound on the outer surface 2a of the hub 2.
Referring now to the magnified vertical cross
section of the hub shown in Figure 2 (taken along
line Il-Il in Figures 1 and 3) and the magnified
transverse section thereof shown in Figure 3 (taken
along line Ill-Ill in Figure 2), it will be noted that the
end of the hub on which the separately molded
flange is attached has a nub 3 which projects
therefrom at a position corresponding to the central
axis of the hub. This nub 3 is pressed by a resilient
member within the cassette casing of the video tape
recorder. The same end of the hub also has fixing
projections 4 which, after being passed through
correspondingly positioned holes in the flange 1 a,
are welded to the flange 1 a by ultrasonic welding or
the like.
On the opposite end of the hub 2 is the second
flange 1 b which may be molded integrally with the
hub 2 or be attached thereto after molding. The
flange 1b has an opening leading into a cylindrical
cavity Sin the interior of the hub 2 for receiving the
tape-driving spindle of the video tape recorder. As is
well known, this spindle has radially projecting ribs
positioned at appropriate intervals about the portion
thereof which enters the cylindrical cavity 5. On the
other hand, the wall defining the cylindrical space 5
is provided with a plurality of ribs 6 which extend in
the axial direction of the hub at appropriate intervals
and project radially into the cylindrical space 5.Thus,
when the spindle of the video tape recorder enters
into the cylindrical space 5, the ribs thereof engage
with the recesses 7 formed between adjacent ribs 6
of the hub 2 and in this way the spindle and the reel
are functionally interconnected so as to rotate as one
body.
Ordinarily, in addition to the structure so far
described, the tape reel is further given a double
walled structure by being provided with an exterior
cylindrical wall 8 the outer surface of which consti
tutes the hub's outer surface 2a and an interior
cylindrical wall 9 which defines the cylindrical space
5 for receiving the spindle of the video tape recorder.
The two cylinders are generally joined by a plurality
of spokes 10. This construction not only has the
advantage of economising the amount of material required but also is effective in minimizing the
thickness of the hub wall members in the radial
direction and therefore helps to prevent the defor
mation that arises when uneven hardening occurs
during the hardening process following molding, this uneven hardening being more pronounced for grea
terwall thicknesses and volume.
The most important factors requiring a high
degree of precision in this conventional reel are the
position and degree of finish of the central nub 3, the external diameter and degree of finish of the hub 2,
the internal diameter, positioning accuracy, degree
of finish and uniformity of strength of the ribs 6 for
engaging the spindle of the video tape recorder. In
the conventional reel, it has been possible to obtain ì a degree of precision in respect of the central nub
and the external diameter of the hub that almost
fully meets design specifications. There has, howev
er, remained a considerable problem in connection
with the molding of the engaging ribs 6.This is because the thickness of the interior cylindrical wall 9 is considerably greater at the portions 9a where the ribs 6 are formed than at the portions 9b where the recesses 7 are formed so that these two portions have a large difference in strength which prevents even distribution of stress. Moreover, since the portions 9a have considerable thickness they are, as was mentioned briefly earlier, susceptible to deformation caused by uneven hardening (wherein the exterior regions cool quickly and the interior regions slowly) in the hardening process following molding.
In addition to the problem that arises in connection with the ribs 6, there is another problem in that with the conventional structure molding defects called sink marks are apt to occur at the border beween the hub and the integrally molded flange.
This is because the point P at the top and center of the cylindrical cavity 5 is generally selected as the injection gate in the injection molding process so that variations in the flow rate of the injected synthetic resin occur as it passes through the relatively large passages corresponding to the ribs 6 into the relatively small passage corresponding to the integrally moulded flange 1b.
Now a description is given of the tape reel of the present invention which is of a construction which prevents the occurrence of moulding defects in the formation of the ribs and other reel portions as well as the occurrence of sink marks.
Figure 4 shows the tape reel according to the present invention in a cross-sectional view corresponding to that of the conventional tape reel shown in Figure 3. In the following description, elements of the tape reel according to the present invention which correspond to those of the conventional tape reel illustrated in Figures 1 to 3 will be designated by the same reference numerals as those of the conventional tape reel.A comparison of the tape reel of the present invention with the conventional tape reel shown in Figures 1 to 3 shows that the improvement lies in the provision of grooves 11 extending in the axial direction behind the respective rib 6 for engaging the spindle, namely in the fact that the back side of each thick portion of the interior cylindrical wall where a rib is provided is grooved so that the remaining part of the wall at the rib portion is reduced to a prescribed fixed thickness 9a' at the tip of the rib and both of its sides.
Each groove 11 extends from the end of the hub 2 to which the fixed (integrally moulded) flange is attached to the upper edge 9c of the interior cylindrical wall 9 of the hub 2, as is clearly indicated in the plan view of Figure 5. From the exterior, the grooves 11 appear to divide the upper edge 9e of the interior cylindrical wall into a number of petals.
This construction is advantageous in that moulding deformation that might otherwise occur due to excessive thickness of the ribs 6 is prevented and, moreover, as the arrangement of the present invention means that in the molding process there is little difference in volume or cross-sectional area between the rib section and the connecting region between the hub 2 and the flange 1 b, variation in flow rate of the synthetic resin material is reduced and overall deformation of the tape reel is minimized.
As was mentioned above, the injection gate in conventional tape reels has been located in the center of the roof of the cylindrical cavity 5 for receiving the spindle of the video tape recorder, and as a consequence, there often remained a gate mark in the form of a small projection at this point. Since there is a possibility of this projection coming in contact with the top of the spindle, its presence gives rise to problems of precision which run counter to the spirit of this invention. To cope with this problem, it is possible, for example, to move the position of the injection gate in the molding die to the top center of the nub 3 and form a slight hollow (as shown by imaginary line C in Figure 2) in the nub 3 so that any gate mark formed would not project above the height of the nub 3.Or, even more preferably, it is possible to move the gate to the position G (Figures 2 and 5) at the top of one of the fixing projections 4 for attachment of the separately molded flange 1 a. By this method, any remaining gate mark would, regardless of shape, be flattened together with the fixing projection 4 at the time the flange 1a was attached to the hub 2 by ultrasonic welding so that no gate mark whatsoever would remain on the finished tape reel.
To even further heighten the effectiveness of the application of this invention, the uniform flow of synthetic resin material even to the extremities of the integrally molded flange 1 b can be assured by, as shown in Figure 6, providing a plurality of radial spokes 12 extending along the back face of the flange 1 b between the interior cylindrical wall 9 and the periphery of the flange. The provision of the ribs 12 between the interior cylindrical wall 9 and concentrically arranged secondary cylindrical wall 8' is particularly useful because this serves to form reservoirs in the runners in the area where the hub 2 joins the opposite side of the flange 1 b and assures a smooth flow of synthetic resin material. In the drawing, the cutaway portion 13 is the tape end holder and has no direct relation to the present invention. As it is well known, it is not described here.
As will be clear from the above description, in accordance with the present invention, the ribs for engaging the spindle, which has been the region most apt to have excessive thickness, are reduced to a uniform, small wall thickness so that there can be obtained a tape reel of high dimensional precision, good moldability and excellent strength distribution.
Claims (5)
1. A plastic tape reel for video cassette comprising a pair of flanges and a hub moulded integrally with one of the pair of flanges and connected to the other of the pair of flanges, which hub is comprised of an exterior cylindrical wall for receiving wound tape on its outer surface and an interior cylindrical wall having an internal cylindrical cavity opening through the integral flange for receiving the spindle of a video tape recorder therein, the interior cylindrical wall being provided on its inner surface with a plurality of regularly spaced ribs projecting radially inward and extending axially of the interior cylindrical wall for engaging with the spindle, further comprising axially extending grooves provided in the back of the interior cylindrical wall at positions behind the ribs.
2. A tape reel for video#cassette in accordance with claim 1, wherein the grooves extend to the peripheral edge at the end of the interior cylindrical wall opposite the integral flange.
3. A tape reel in accordance with claim 1 or claim 2, wherein the flange attached to the end of the hub opposite that through which the internal cylindrical cavity for receiving the spihdle opens is a separately moulded flange which permits a nub provided at the centre of said end to pass therethrough, accommodates fixing projections provided on said end and is fixed to said end by ultrasonic welding which flattens the heads of the fixing projections.
4. A tape reel in accordance with claim 3, wherein the synthetic resin injection gate for moulding the hub and the integral flange is located at the tip of a fixing projection for the other separately moulded flange.
5. A tape reel for video cassette, substantially as herein described with reference to Figures 4, 5 and 6 of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15859478A JPS5587352A (en) | 1978-12-25 | 1978-12-25 | Tape reel for video cassette |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2040264A true GB2040264A (en) | 1980-08-28 |
| GB2040264B GB2040264B (en) | 1983-01-26 |
Family
ID=15675088
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7944001A Expired GB2040264B (en) | 1978-12-25 | 1979-12-20 | Tape reel for video cassette |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5587352A (en) |
| DE (1) | DE2952350A1 (en) |
| ES (1) | ES255188Y (en) |
| FR (1) | FR2445583B1 (en) |
| GB (1) | GB2040264B (en) |
| IT (1) | IT1127314B (en) |
| NL (1) | NL7909281A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4723731A (en) * | 1985-08-14 | 1988-02-09 | Gefitec S.A. | Reel of plastics material for magnetic tape |
| US4807826A (en) * | 1986-12-12 | 1989-02-28 | Sony Corporation | Tape reel for tape cassette |
| EP0902429A1 (en) * | 1997-09-10 | 1999-03-17 | TDK Corporation | Tape reel for tape cassette |
| EP1204113A1 (en) * | 1999-06-23 | 2002-05-08 | Fuji Photo Film Co., Ltd. | Magnetic cassette tape reel |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS609079U (en) * | 1983-06-29 | 1985-01-22 | ポリプラスチックス株式会社 | Synthetic resin tape reel |
| JPS6056989U (en) * | 1983-08-22 | 1985-04-20 | 日立マクセル株式会社 | tape cartridge |
| JPS60111582U (en) * | 1983-12-28 | 1985-07-29 | ポリプラスチックス株式会社 | tape reel parts |
| JPS6173290A (en) | 1984-09-17 | 1986-04-15 | Sony Corp | Tape cassette |
| JPS61187081U (en) * | 1985-05-08 | 1986-11-21 | ||
| FR2586319B1 (en) * | 1985-08-14 | 1987-12-18 | Gefitec Sa | PLASTIC COIL FOR MAGNETIC TAPE, PRISONER OF A CASSETTE CASE |
| JPS6273379U (en) * | 1985-10-29 | 1987-05-11 | ||
| US4715558A (en) * | 1986-02-24 | 1987-12-29 | Ampex Corporation | Single piece tape reel and assembly |
| JPH0763982B2 (en) * | 1986-05-26 | 1995-07-12 | ポリプラスチックス株式会社 | Method for manufacturing tape |
| EP0247822A3 (en) * | 1986-05-26 | 1989-05-17 | Polyplastics Co. Ltd. | Method of manufacturing tape reel |
| JPH0632189B2 (en) * | 1986-06-06 | 1994-04-27 | ポリプラスチックス株式会社 | Method for manufacturing tape |
| JPS63307919A (en) * | 1987-06-10 | 1988-12-15 | Polyplastics Co | Molding method for tape reel |
| CA2043395A1 (en) * | 1990-05-29 | 1991-11-30 | In J. Kim | Tape reel capable of preventing the tape from being damaged |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2853175A (en) * | 1955-09-19 | 1958-09-23 | Regentrop Paul | Spools for typewriter ribbons |
| US3617013A (en) * | 1969-06-27 | 1971-11-02 | Eastman Kodak Co | Cartridge |
| US3823947A (en) * | 1970-09-25 | 1974-07-16 | Hitachi Maxell | Magnetic recording tape |
| JPS521955U (en) * | 1975-06-23 | 1977-01-08 | ||
| JPS52146118U (en) * | 1976-04-30 | 1977-11-05 | ||
| JPS5728305Y2 (en) * | 1977-05-20 | 1982-06-21 | ||
| JPS6220931Y2 (en) * | 1978-03-04 | 1987-05-27 |
-
1978
- 1978-12-25 JP JP15859478A patent/JPS5587352A/en active Granted
-
1979
- 1979-12-20 GB GB7944001A patent/GB2040264B/en not_active Expired
- 1979-12-21 NL NL7909281A patent/NL7909281A/en not_active Application Discontinuation
- 1979-12-24 IT IT28380/79A patent/IT1127314B/en active
- 1979-12-24 FR FR7931615A patent/FR2445583B1/en not_active Expired
- 1979-12-24 DE DE19792952350 patent/DE2952350A1/en not_active Withdrawn
- 1979-12-24 ES ES1979255188U patent/ES255188Y/en not_active Expired
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4723731A (en) * | 1985-08-14 | 1988-02-09 | Gefitec S.A. | Reel of plastics material for magnetic tape |
| US4807826A (en) * | 1986-12-12 | 1989-02-28 | Sony Corporation | Tape reel for tape cassette |
| EP0902429A1 (en) * | 1997-09-10 | 1999-03-17 | TDK Corporation | Tape reel for tape cassette |
| US6311917B1 (en) * | 1997-09-10 | 2001-11-06 | Kenji Hashizume | Tape reel for tape cassette |
| EP1204113A1 (en) * | 1999-06-23 | 2002-05-08 | Fuji Photo Film Co., Ltd. | Magnetic cassette tape reel |
| EP1204113A4 (en) * | 1999-06-23 | 2008-05-07 | Fujifilm Corp | Magnetic cassette tape reel |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5587352A (en) | 1980-07-02 |
| GB2040264B (en) | 1983-01-26 |
| FR2445583A1 (en) | 1980-07-25 |
| IT1127314B (en) | 1986-05-21 |
| IT7928380A0 (en) | 1979-12-24 |
| FR2445583B1 (en) | 1987-11-20 |
| NL7909281A (en) | 1980-06-27 |
| ES255188U (en) | 1981-07-16 |
| ES255188Y (en) | 1982-04-01 |
| DE2952350A1 (en) | 1980-07-03 |
| JPS6142340B2 (en) | 1986-09-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| GB2040264A (en) | Tape reel for video cassette | |
| US4932604A (en) | Tape cartridge | |
| US4706149A (en) | Tape cassette | |
| US4262856A (en) | Tape reel | |
| US6043962A (en) | Tape cassette and metal mold device for molding tape cassette halves | |
| JPS6140786U (en) | tape reel | |
| JP5377139B2 (en) | Reel and recording tape cartridge | |
| US5174520A (en) | Tape cassette reel having an upper reel portion formed by dichromatic molding method | |
| US6758428B1 (en) | Tape reel for use in magnetic tape cassette | |
| KR830000376Y1 (en) | Tape reel for video cassette | |
| US6266319B1 (en) | Disc cartridge integrally formed of transparent and non-transparent resin, and molding die therefor | |
| JP4841668B2 (en) | Tape reel flange and its mold for tape cartridges | |
| JPH073518Y2 (en) | Cassette half | |
| EP0247821A2 (en) | Method of manufacturing tape reel | |
| JP2547477Y2 (en) | Magnetic tape cassette | |
| JPH03263670A (en) | Tape reel and tape cassette equipped with tape reel and manufacture of tape reel | |
| JPH0596965U (en) | Molding cassette base | |
| JPH0519902Y2 (en) | ||
| JP2592451Y2 (en) | Magnetic tape cassette | |
| JP2962656B2 (en) | Disk cartridge | |
| JP2007055169A (en) | Injection molding die, injection molding method, tape reel and tape cartridge | |
| JPS5822308Y2 (en) | tape reel | |
| JPH054146Y2 (en) | ||
| JP2002100151A (en) | Flange of tape reel for tape cartridge and molding die for the same | |
| JPH0441508Y2 (en) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |