GB2025898A - A magnetic tape cassette case - Google Patents
A magnetic tape cassette case Download PDFInfo
- Publication number
- GB2025898A GB2025898A GB7923220A GB7923220A GB2025898A GB 2025898 A GB2025898 A GB 2025898A GB 7923220 A GB7923220 A GB 7923220A GB 7923220 A GB7923220 A GB 7923220A GB 2025898 A GB2025898 A GB 2025898A
- Authority
- GB
- United Kingdom
- Prior art keywords
- screw
- magnetic tape
- tape cassette
- screws
- case
- 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
- 239000004033 plastic Substances 0.000 claims abstract description 14
- 229920003023 plastic Polymers 0.000 claims abstract description 14
- 238000010079 rubber tapping Methods 0.000 claims abstract description 6
- 238000005336 cracking Methods 0.000 abstract description 12
- 239000000463 material Substances 0.000 abstract description 3
- 230000002265 prevention Effects 0.000 abstract 1
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 6
- 239000011347 resin Substances 0.000 description 6
- 229920005989 resin Polymers 0.000 description 6
- 229920000178 Acrylic resin Polymers 0.000 description 3
- 239000004925 Acrylic resin Substances 0.000 description 3
- -1 polypropylene Polymers 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229930040373 Paraformaldehyde Natural products 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229920006324 polyoxymethylene Polymers 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- GDVWDDRKKYMHKS-UHFFFAOYSA-N hepta-1,4,6-trien-3-one;styrene Chemical compound C=CC=CC(=O)C=C.C=CC1=CC=CC=C1 GDVWDDRKKYMHKS-UHFFFAOYSA-N 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B25/00—Screws that cut thread in the body into which they are screwed, e.g. wood screws
- F16B25/001—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by the material of the body into which the screw is screwed
- F16B25/0015—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by the material of the body into which the screw is screwed the material being a soft organic material, e.g. wood or plastic
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B25/00—Screws that cut thread in the body into which they are screwed, e.g. wood screws
- F16B25/0036—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by geometric details of the screw
- F16B25/0042—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by geometric details of the screw characterised by the geometry of the thread, the thread being a ridge wrapped around the shaft of the screw
- F16B25/0073—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by geometric details of the screw characterised by the geometry of the thread, the thread being a ridge wrapped around the shaft of the screw characterised by its pitch, e.g. a varying pitch
-
- 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
- G11B23/04—Magazines; Cassettes for webs or filaments
- G11B23/08—Magazines; Cassettes for webs or filaments for housing webs or filaments having two distinct ends
- G11B23/087—Magazines; Cassettes for webs or filaments for housing webs or filaments having two distinct ends using two different reels or cores
- G11B23/08707—Details
- G11B23/08785—Envelopes
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Dispersion Chemistry (AREA)
- Wood Science & Technology (AREA)
- Physics & Mathematics (AREA)
- Geometry (AREA)
- Packaging Of Annular Or Rod-Shaped Articles, Wearing Apparel, Cassettes, Or The Like (AREA)
- Casings For Electric Apparatus (AREA)
Abstract
A magnetic tape cassette case 1 having a pair of rectangular half cases 2,3 made of plastics material, are connected together by a plurality of self-tapping screws, wherein said screw is a multiple thread screw for reducing the cracking of the plastics half-cases and the prevention of loose screws. <IMAGE>
Description
SPECIFICATION
A magnetic tape cassette case
The present invention relates to the structure of a case or a housing of a magnetic tape cassette.
Generally speaking, the housing of a tape cassette consists of, as shown in Fig. 1, a case or a housing 1 having a plastic upper half-case 2 and plastic lower half-case 3 held together by a plurality of screws 4, through 45, and reels (not shown) with a tape 5 wound thereon, which are held within the case 1. For connection the two half-cases of the cassette case, screws with a single thread 6 of selftapping type (as shown in Fig. 2), are utilized. With a self-tapping type screw, a nut is not necessary, but the screw engages directly with plastic.
For assembling the two half-cases by the self-tapping type screws, those portions of one halfcase which are to be tapped are provided with preliminary holes having a slightly larger diameter than the core diameter of the thread but is slightly smaller than the outer diameter of the screw while the portions of the mating half-case which correspond to the preliminary holes are provided with through holes the diameter of which are slightly larger than the outer diameter of the screws. The self-tapping screw at first penetrates the large through hole until reaching the small preliminary hole. Then, as the screw is turned, the preliminary hole is tapped and the screw proceeds accordingly, so as to firmly connect the two half-cases.
However, the conventional case of a magnetic tape cassette as mentioned above has the following disadvantages.
It is well known that the dimensions and the shape of the plastics half-cases used for a cassette tape can be easily altered depending upon the shaping conditions during the manufacturing process along with fluctuations of the temperature and/or humidity of the surrounding atmosphere. The dimensions of the preliminary holes bored on the half-cases are also altered as a result of the mentioned dimension alteration of the half-cases. Accordingly, the clamping torque by screws tends to change as the effects of the dispersion of the preliminary hold dimension. More particularly, if the diameter of the preliminary hole is too large, the screw tends to be come loose with respect to the engagement with the preliminary hole. And when the diameter of the preliminary hole is too small, the mechanical clamping tends to end up in an under-clamping, causing shortage of the clamping strength.
Defective assembly of the two half-cases greatly deteriorates the parallelness of planes of the case of a cassette tape, which could cause the deterioration of the sound quality and disturbance of tape running. Further, the over-clamping of screws tends to cause cracking and warps of the plastics halfcases.
Embodiments of the present invention seek to overcome the disadvantages and limitations of known magnetic tape cassette cases and to provide a tape cassette case which is substantially free from the cracking of the plastics half cases, and the loosening of screws.
According to the invention there is provided a magnetic tape cassette case comprising a pair of substantially rectangular half cases made of plastics for the mounting of a magnetic tape wound on a reel, with said half cases being connected together by a plurality of self-tapping multiple thread screws.
An embodiment of the invention will now be described by way of example with reference to the accompanying drawings wherein:~
Fig. 1 is a perspective view of a cassette tape case according to the present invention,
Fig. 2 is a side view of the essential portion of a-single thread screw which has been used in conventional cassette tape cases,
Fig. 3 is an explanatory drawing showing the lead angle and the pitch of a scew,
Fig. 4 is a side view of the essential portion of a multi-thread screw which is used in a cassette tape case according to the present invention, and
Fig. 5 shows the curves of the experimental result of a cassette tape case embodying the present invention.
The inventors of this present invention discovered that cracking of the plastics and/or loose screws depend upon the lead angle (0) and the pitch (p) of thescrews. The lead angle (0) of a screw is, as shown in Fig. 3, the angle between the thread and the lateral direction to the screw axis, and the pitch (p) of a screw is the duration between the threads of a screw. Also, the present inventors discovered that the screw with a larger lead angle (0) thatn that of a single thread screw, is excellent for the connection of a cassette tape case. However, since a screw with large lead angle has also large pitch, a conventional single thread screw as shown in Fig. 2 is not preferable for connecting a cassette tape housing.
Accordingly, multiple thread screws, for instance two threads 7 and 8 as shown in Fig. 4, or, three or more threads are utilized for assembling the two half-cases of a cassette tape case, instead of the
conventionally used single thread screws. With the multiple thread screws, the occurrence of loose
screws or floating screws, and/or cracking of the plastic can be eliminated. So, that the parallelness of the planes of each half-cases can be maintained and, then excellent sound quality and smooth tape
running are obtained. Also, the time necessary for clamping the two half-cases can be shortened and with this the productivity of a cassette tape case can be improved.
The following table shows the experimental result concerning the relation between the number of cracking occurred, and the number of samples of various plastics resins both for the single thread screw construction and for the multiple thread screw construction.
TABLE
Resin (material of half-cases) Styrene resin, Acrylic resin, ABS Type of screw used transparent transparent (Acryl-Butadiene-Styrene) Single thread screws 12/20 13/20 4/20 (prior art) (prior art) Double thread screws 0/20 1/20 0/20 It is quite apparent from the table, that the number of cracking has been considerably reduced by utilizing the present double threads screws. And, in particular, excellent effects were achieved in transparent products such as styrene resin and acrylic resin, wherein the,attractive appearance is particularly important.
Fig. 5 shows the curve of the experimental result concerning the relationship between the lead angle, cracking, and loose screws. The horizontal axis in Fig. 5 shows the lead angle (degree), the vertical axis shows the ratio (%) of the cracking (right side) and the loose screw (left side). The curve (A) shows the relation between the lead angle and the cracking, and the curve (B) shows the relation between the lead angle and the loose angle. The symbol (P) shows the relation between the lead angle and the pitch (mm) of a single thread screw, the symbol (Q) shows the relation between the lead angle and the pitch (mm) of a two thread screw. The symbol (R) shows the relation between the lead angle and the pitch in millimetres of a three thread screw.The plastics materials tested in the experiment in
Fig. 5 are polycarbonate, denatured polyphenyloxide, polypropylene, polyethylene, polyester, polyvinyle chloride resin (PVC), acryle-butadiene-styrene (ABS), acrylenitrile-sstyrene (AS), acrylic resin, polyoxymethylene (POM), polystyrene (PS), and styrene resin.
It is apparent in Fig. 5, that a screw of the feature in the shaded area of that figure is the most preferable one for the minimum of cracking and the allowable loosening of the screw. Accordingly the proven preferable screw for a cassette tape case is a double thread screw with the lead angle from 120 to 190 and the pitch from 0.7 mm to 1.1 mm, and a three thread screw with the lead angle of approximate 1 90 with the pitch of approximate 0.6 mm, where the pitch is defined by the duration between the adjacent threads as shown in Fig. 3.
Other experimental conditions of Fig. 5 are that the diameter of a screw is approximately 2 mm (made of soft iron), and the size of a magnetic tape of cassette case is approximate 100 x 65 x 9 mm.
As described before in detail, the embodiment described with reference to the drawings provides a cassette tape case which is superior in appearance and performance, has a small cracking ratio and loosening of screws, as compared with a conventional cassette tape case.
From the foregoing, it should now be apparent, that a new and improved cassette tape case has been found. It should be understood of course that the embodiments disclosed are merely illustrative and are not intended to limit the scope of the invention. Reference should be made to the appended claims, therefore, rather than the specification as indicating the scope of the invention.
Claims (5)
1. A magnetic tape cassettevcase comprising a pair of substantially rectangular half cases made of plastics for the mounting of a magnetic tape wound on a reel, with said half cases being connected together by a plurality of self-tapping multiple thread screws.
2. A magnetic tape cassette according to Claim 1 wherein said screw is a double thread screw with the lead angle in the range 120 to 190.
3. A case of a magnetic tape cassette according to Claim 2 wherein the pitch of said screw is in the range from 0.7 mm to 1.1 mm.
4. A magnetic tape cassette according to Claim 1 wherein said screw is a three thread screw with the lead angle of approximately 190 and the pitch of approximately 0.6 mm,
5. A magnetic tape cassette according to Claim 1, substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9315578U JPS5511655U (en) | 1978-07-06 | 1978-07-06 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2025898A true GB2025898A (en) | 1980-01-30 |
| GB2025898B GB2025898B (en) | 1982-07-14 |
Family
ID=14074646
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7923220A Expired GB2025898B (en) | 1978-07-06 | 1979-07-04 | Magnetic tape cassette case |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS5511655U (en) |
| DE (1) | DE2926353C2 (en) |
| GB (1) | GB2025898B (en) |
| NL (1) | NL178728C (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0214604A2 (en) * | 1985-09-04 | 1987-03-18 | Hitachi Maxell Ltd. | Tape cartridge |
| EP0905388A1 (en) * | 1997-09-30 | 1999-03-31 | HILTI Aktiengesellschaft | Anchoring bolt |
| EP1104929A1 (en) * | 1998-07-17 | 2001-06-06 | Fuji Photo Film Co., Ltd. | Magnetic tape cartridge |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT7921232V0 (en) * | 1979-03-30 | 1979-03-30 | Ingramatic Spa | SCREW STRUCTURE WITH TWO-PRINCIPLE THREAD. |
-
1978
- 1978-07-06 JP JP9315578U patent/JPS5511655U/ja active Pending
-
1979
- 1979-06-29 DE DE19792926353 patent/DE2926353C2/en not_active Expired
- 1979-07-04 NL NL7905222A patent/NL178728C/en not_active IP Right Cessation
- 1979-07-04 GB GB7923220A patent/GB2025898B/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0214604A2 (en) * | 1985-09-04 | 1987-03-18 | Hitachi Maxell Ltd. | Tape cartridge |
| EP0214604A3 (en) * | 1985-09-04 | 1989-06-07 | Hitachi Maxell Ltd. | Tape cartridge |
| EP0905388A1 (en) * | 1997-09-30 | 1999-03-31 | HILTI Aktiengesellschaft | Anchoring bolt |
| EP1104929A1 (en) * | 1998-07-17 | 2001-06-06 | Fuji Photo Film Co., Ltd. | Magnetic tape cartridge |
| EP1104929A4 (en) * | 1998-07-17 | 2004-03-31 | Fuji Photo Film Co Ltd | Magnetic tape cartridge |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2926353A1 (en) | 1980-01-17 |
| GB2025898B (en) | 1982-07-14 |
| DE2926353C2 (en) | 1984-04-05 |
| JPS5511655U (en) | 1980-01-25 |
| NL7905222A (en) | 1980-01-08 |
| NL178728B (en) | 1985-12-02 |
| NL178728C (en) | 1986-05-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |