JP3005694U - Magnetic tape cassette - Google Patents

Abstract

(57) [Summary] [Purpose] A reel pressure spring capable of elastically pressing the reel without excessive deformation so that the tape reel can rotate stably and the tape can run smoothly, and can be manufactured at low cost. There is provided a magnetic tape cassette provided with. The magnetic tape cassette includes an upper casing and a lower casing that receive a pair of tape reels and are joined together along a peripheral portion, and a spring 34 that elastically presses the tape reel against the lower casing. This spring has a central portion 38 fixed to the upper casing, both end portions 36 for pressing the reel, and an inclined intermediate portion 44 formed between the central portion and the end portions, respectively. The central portion and the intermediate portion are connected via the first transition portion 46, and the intermediate portion and both end portions are connected via the second transition portion 48. A pair of lateral ribs 50 facing the upper casing is formed in the middle part in the vicinity of the first transition part.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a magnetic tape cassette housed and used in a tape recorder, and more particularly to a magnetic tape cassette equipped with a pressure spring that elastically presses a pair of reels housed therein. .

[0002]

[Prior art]

 Generally, a magnetic tape cassette includes an upper casing and a lower casing configured to be coupled to each other along the outer peripheral edge thereof, and accommodates a pair of reels having a magnetic tape wound therein. . The drive shaft of the tape recorder is inserted into the reel through a through hole formed in the lower side of the reel to rotate the reel when playing and recording the tape. Therefore, the magnetic tape cassette is usually provided with a spring capable of downwardly pressing the reel so that the reel can rotate while maintaining a smooth and horizontal balance.

Many types of reel pressure springs are known in the art. U.S. Pat. No. 4,496,118 to Kengo Oishi and Osamu Suzuki discloses a magnetic tape cassette having a reel pressure plate spring fixedly secured to the upper casing while aligned with the photosensor insertion hole. Although the fixing force of the spring of this cassette is greatly improved, both ends of the spring are easily deformed, so that the middle part of the cassette can come into contact with the reel to prevent the tape from running.

Shinichi Goto, in US Pat. No. 4,368,860, discloses a magnetic tape cassette having a recess capable of receiving a fixing portion of a spring member on the lower surface of an upper case, in order to solve the above-mentioned problems. did. However, this cassette has a problem in that the force of the spring member must be larger than that of the above-mentioned patent in order to press the reel so that the reel does not come into contact with the sleeve portion of the upper case.

Although such drawbacks can be overcome by increasing the strength of the spring, the restoring force of the spring may be reduced or the amount of material used for the spring may be increased. No increase is adopted. Therefore, there is a need for a pressure spring that has a structure that can increase the strength without reducing the restoring force. It would be further desirable if the pressure spring could be manufactured from a cheaper material to reduce the cost of manufacturing the tape cassette.

[0006]

[Problems to be solved by the device]

 SUMMARY OF THE INVENTION Therefore, an object of the present invention is to overcome the above-mentioned drawbacks of the prior art and to provide a magnetic tape cassette having a pressing spring that can elastically press the magnetic tape reel so that it can rotate smoothly.

Another object of the present invention is to provide a magnetic tape cassette that can be manufactured at low cost while preventing excessive deformation of the reel.

[0008]

[Means for Solving the Problems]

 The object of the present invention is to provide upper and lower casings, which are connected to each other along a peripheral portion, a pair of reels on which magnetic tape is wound, and elastically press the reels toward the lower casing. In a magnetic tape cassette including a reel spring, the reel spring is formed between a central portion fixed to the upper casing; both end portions for pressing the reel; and a central portion and an end portion, respectively. The middle part and the middle part are connected to each other via the first transition part, the middle part and both end parts are connected to each other via the second transition part, and This is achieved by a magnetic tape cassette in which a pair of lateral leaves are formed in the middle part in the vicinity of the first transition part toward the upper casing.

[0009]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram of a video tape cassette according to the present invention, which is designated by reference numeral 10. The videotape cassette includes upper and lower casings 12,14 that are assembled together, the tape cassette shaped to fit in a tape recorder (not shown) such as a VCR.

A pair of rotatable reels 16 is housed in the upper and lower casings, and a magnetic tape 18 is wound around these reels. Each reel 16 comprises two disc-shaped discs 20, 22 and a drum-type hub 24 connecting the discs at the center of each disc. One end 26 of the hub is closed and the other end 30 is an open blind hole, and the closed end 26 is provided opposite to the upper casing 12 and supports a protrusion 28 capable of pivoting movement. The open end 30 is provided so as to face the lower casing 14, and a through hole 32 is formed in a corresponding portion of the lower casing corresponding to the open end. The drive shaft of the tape recorder is inserted in the through hole 32 to rotate the reel.

A reel pressure spring (collectively indicated as 34) made of metal or plastic is attached to the lower surface of the upper casing 12. The pressure spring 34 is in the form of an elongated plate and has a central portion 38 and both end portions 36 which are placed parallel to each other as shown in the drawing. The central portion 38 is provided with a through hole 40 at a position corresponding to a boss 42 projecting from the inner surface of the upper casing so that it can be fixed to the center of the upper casing 12 by riveting or caulking. Those skilled in the art will appreciate that the reel spring is adapted such that the two end portions 36 can bias the upper surface of the closed end 26 of the reel hub 24.

As clearly shown in FIG. 2, an inclined intermediate portion 44 is formed between the central portion 38 and both end portions 36. The sloped portion 44 is set so that the boundary with the central portion 38 is set by the first transition portion 46 and the boundary with the both end portions 36 is set by the second transition portion 48. The structure of the first and second transition portions is to allow both end portions 36 of the spring 34 to contact only the protrusion 28 of the reel.

A pair of lateral rib groups 50 facing the upper casing 12 is formed in the intermediate portion 44 in the vicinity of the first transition portion 46. The ribs of this group of ribs 50 are parallel to each other, and are preferably equidistant from each other, forming a parabolic aggregate, as seen in FIG. Such a structure is intended to allow at least half of the ribs near the central portion 38 to make uniform contact with the upper casing and the remaining ribs will not contact the upper casing. Those skilled in the art have adopted the rib group 50 to increase the pressing force for urging the reel, so that excessive deformation that would hinder the smooth rotation of the reel or the smooth running of the tape is avoided. I understand.

The pressure spring 34 of the present invention is generally made of an elastically deformable material such as stainless steel. However, since the downward elastic force of the pressure spring is sufficiently increased by using the structure described above, the reel pressure spring of the present invention is manufactured from a substance other than metal, for example, a synthetic resin such as polyethylene or polyacetal. You could also

[0016]

[Effect of device]

 As described above, according to the present invention, since the relieve group is provided in the middle portion of the pressure spring to enhance the elastic force, not only the deformation of the pressure spring can be prevented but also the reel of the pressure spring can be prevented. Smooth rotation and smooth running of the tape are also ensured. Also, springs could be made from cheaper materials, which could reduce manufacturing costs.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing a video tape cassette having a pressure spring according to the present invention.

FIG. 2 is an enlarged perspective view of a pressure spring of the present invention.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a partially enlarged perspective view of FIG. 3 showing the installation state of the pressure spring in more detail.

[Explanation of symbols]

 10 Video Tape Cassette 12 Upper Casing 14 Lower Casing 16 Reel 18 Video Tape 20, 22 Flange 24 Hub 26 Closed End 28 Protrusion 30 Open End 32 Through Hole 34 Pressure Spring 36 End Portion 38 Center Part 40 Through Hole 42 Boss 44 Sloped Intermediate part 46 First transition part 48 Second transition part 50 Lateral rectangular rib group

Claims (4)

[Scope of utility model registration request] 1. An upper and lower casing coupled to each other along a peripheral edge; a pair of reels around which a magnetic tape is wound; and a reel spring for elastically pressing the reel toward the lower casing. In the magnetic tape cassette, the reel spring has a central portion fixed to the upper casing; both end portions for pressing the reel; and inclined portions formed between the central portion and the end portion. An intermediate portion, the central portion and the intermediate portion are connected to each other via a first transition portion, the intermediate portion and both end portions are connected to each other via a second transition portion, and the intermediate portion A magnetic tape cassette having a pair of lateral ribs formed in the vicinity of the first transition portion toward the upper casing. 2. The magnetic tape cassette according to claim 1, wherein the lateral ribs have a parabolic shape so that the ribs adjacent to the central portion can come into contact with the upper casing. 3. The magnetic tape cassette according to claim 1, wherein the reel spring is made of an elastically deformable plastic material. 4. The magnetic tape cassette of claim 3, wherein the plastic material is made of polyethylene or polyacetal.