Tape reel for tape cassette

Abstract: A tape reel (10) for a tape cassette capable of substantially preventing deformation thereof, even when it is thin-walled to substantially reduce a cycle time required for a molding step of the tape reel. The tape reel (10) includes a reel hub (2) and a disc-like flange (1). Reinforcing ribs (4, 6) include an annular rib (6) arranged on an outer peripheral surface of the disc-like flange (1) and a plurality of linear ribs (4) arranged on an outer surface of the disc-like flange (1) so as to extend from a core stabilizing surface rib (5) to the annular rib (6). The linear ribs (4) are so arranged that each of the linear ribs (4) intersects at least one of the other linear ribs (4) at a position (4 1 ) which is further than a midpoint between the core stabilizing surface rib (5) and the annular rib (6).

Description: BACKGROUND OF THE INVENTION This invention relates to a tape reel for a tape cassette, and more particularly to a tape reel adapted to be rotatably incorporated in a tape cassette to take up a tape thereon and deliver it therefrom. A conventional tape reel used for such a purpose includes a reel flange, which is provided on a bottom surface thereof or a surface thereof opposite to a tape receiving surface thereof with reinforcing ribs in a manner to radially or concentrically extend thereon in order to prevent deformation of the reel flange due to a weight of a tape wound on the tape reel, as disclosed in, for example, GB -A-2009101. However, an increase in width of the reinforcing rib to a level larger than the thickness of the flange causes sink marks to occur on the surface of the flange on which the ribs are not provided or the above-described tape receiving surface of the flange. Thus, in the conventional tape reel, it is required that the reinforcing ribs are formed with a width equal to or smaller than the thickness of the reel flange. Also, weight-saving to reduce reel manufacturing cost requires reduction of the thickness of the reel flange and concurrently of the width of the reinforcing ribs to avoid sink marks. Unfortunately, in the conventional tape reel in which the reinforcing ribs are radially or concentrically arranged reducing the thickness of the flange causes an increase in warpage of the flange and/or deflection thereof when the cycle time for molding the tape reel is reduced; whereas variation in shape of an inner side of a reel stabilizing surface of the tape reel and/or shape of the ribs or an increase in the number of ribs causes an increase in weight of the tape reel. Thus, the conventional tape reel fails to uniformly reinforce the whole flange while keeping the weight of the flange from being increased. In particular, when the reinforcing ribs formed on the flange are reduced in width for the purpose of preventing sink marks, the flange fails to exhibit sufficient strength or stiffness, so that the weight of a tape wound on the tape reel causes deformation of the reel flange. Such deformation is amplified during storage of the tape reel at high temperature. JP 54 0 80 747U (corresponding to above-mentioned GB-A-2009101) discloses atape reel in which the reel flange has on its outer face a core-stabilizing inner circular rib, an outer peripheral rib, and radial linear ribs joining said inner and outer ribs. EP-A-0136504 discloses a similar structure in which the radial ribs terminate short of the outer rib and are formed by grooves in the inner flange face so that the flange thickness is uniform. FR-A-2531688 discloses a bobbin for a thread, the bobbin flanges having intersecting linear stiffening ribs. SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing disadvantage of the prior art. Accordingly, it is an object of the present invention to provide a tape reel for a tape cassette which is capable of substantially shortening or reducing the cycle time for molding the tape reel. It is another object of the present invention to provide a tape reel for a tape cassette which is capable of preventing deformation thereof due to the weight of a tape wound thereon and restraining deformation thereof during storage thereof at a high temperature. It is a further object of the present invention to provide a tape reel for a tape cassette which is simplified in structure and of reduced manufacturing cost. In accordance with the present invention, a tape reel for a tape cassette is provided. The tape reel includes a reel hub on which a tape can be wound, a disc-like flange molded integrally with the reel hub and having an inner surface to receive the wound tape and an outer surface opposite from the inner surface, a core stabilizing surface rib on the outer surface of the disc-like flange, and reinforcing ribs provided on the disc-like flange. The reinforcing ribs include an annular rib at the outer periphery of the disc-like flange and a plurality of linear ribs on the outer surface of the disc-like flange and extending from the core stabilizing surface rib to the annular rib. The linear ribs are so arranged that each of the linear ribs intersects at least one of the other linear ribs at a position which is further from the core stabilizing rib than the midpoint between the core stabilizing rib and the annular rib. In a preferred embodiment of the present invention, the linear ribs are so arranged that each of the linear ribs intersects at least one of the other linear ribs at a position located on the annular rib. In a preferred embodiment of the present invention, the linear ribs are so arranged that each of the linear ribs intersects another one of the linear ribs at a position located on the core stabilizing surface rib. In a preferred embodiment of the present invention, the linear ribs are so arranged that every two of the linear ribs opposite to each other with the reel hub being interposed therebetween are aligned with each other on a straight line. The linear ribs are so arranged that each linear rib intersects one of the other linear ribs at a position located on the annular rib and intersects another one of the linear ribs at a position located on the core stabilizing surface rib. Thus, the linear ribs in association with each other form a substantially star-like reinforcing rib structure. In a preferred embodiment of the present invention, the linear ribs are each of a base width substantially equal to the thickness of the flange and taper away from the flange so as to be trapezoidal in section. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings; wherein: Fig. 1 is a bottom view showing an embodiment of a tape reel for a tape cassette according to the present invention; Fig. 2 is a vertical sectional view taken along line II-II of Fig. 1; Fig. 3 is an enlarged vertical sectional view taken along line III-III of Fig. 1; Fig. 4 is a bottom view showing another embodiment of a tape reel for a tape cassette according to the present invention; and Fig. 5 is an exploded perspective view showing an example of a tape cassette in which tape reels of the present invention may be incorporated. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A tape reel for a tape cassette according to the present invention will be described hereinafter with reference to the accompanying drawings. Referring first to Figs. 1 to 3, an embodiment of a tape reel for a tape cassette according to the present invention is illustrated. A tape reel of the illustrated embodiment which is generally designated by reference numeral 10 is adapted to be arranged or incorporated in a VHS tape cassette. The tape reel 10 includes a reel hub 2 on which a tape is wound and a first disc-like flange 1 integrally formed with the reel hub 2 by molding so as to be positioned on a lower side thereof. The first disc-like flange 1 is formed so as to have an inner surface on which winding of the tape is carried out, and an outer surface opposite from the inner surface. The tape reel 10 of the illustrated embodiment also includes a core stabilizing surface rib 5 provided on the outer surface of the first disc-like flange 1 and reinforcing ribs provided on the first disc-like flange 1. The tape reel 10 also includes a second disc-like flange 3 arranged so as to be positioned on an upper side of the reel hub 2. The reinforcing ribs include an annular rib 6 arranged on an outer periphery of the first disc-like flange 1 and a plurality of linear ribs 4 arranged on the outer surface of the first disc-like flange 1 in a manner to outwardly project therefrom and extend from the core stabilizing surface rib 5 to the annular rib 6. The linear ribs 4 are so arranged that each of the linear ribs 4 intersects one of the other linear ribs 4 at a position 4 which is further from rib 5 than the midpoint between ribs 5 and 6. In the illustrated embodiment, every adjacent two of the linear ribs 4 are arranged so as to intersect each other at an intermediate position between the core stabilizing surface rib 5 and the annular rib 6, as shown in Fig. 1. Alternatively, the linear ribs 4, as shown in Fig. 4, may be arranged in such a manner that each of the linear ribs 4 intersects one of the other linear ribs 4 at a position 4 1 located on the annular rib 6 and also intersects another one of the linear ribs 4 at a position 4 2 located on the core stabilizing surface rib 5. This results in the linear ribs 4 in association with each other form a substantially star-like reinforcing rib structure. Such construction enhances both aesthetic characteristics of the tape reel and appearance quality thereof. In such a star-like reinforcing rib structure, every two of the linear ribs 4 opposite to each other with the reel hub 2 being interposed therebetween are aligned with each other on a straight line, and each of the linear ribs 4, as described above, alternately intersects two of the other linear ribs 4 adjacent thereto in order on the core stabilizing surface rib 5 and annular rib 6. Such construction facilitates manufacturing of a molding die for the tape reel while reducing the manufacturing cost. Each of the linear ribs 4 may be arranged so as to intersect at least one of the other linear ribs 4 at an intersection 4 1 . Alternatively, each of the linear ribs 4 may further intersect another one of the linear ribs 4 or more at a plurality of intersections. For example, intersecting between each two adjacent linear ribs 4 may be carried out on either only the annular rib 6 or only a flat surface of the first disc-like flange 1. Further, the intersecting may be carried out at a position on each of two or more members selected from the flat surface of the flange 1, core stabilizing surface rib 5 and annular rib 6. Such arrangement of the linear ribs 4 ensures that the first disc-like flange 1 is substantially uniformly reinforced or stiffened, to thereby provide a tape reel free from any deflection or deformation. The linear ribs 4 of the reinforcing ribs, as shown in Fig. 3, may each be formed with a base width t 2 substantially equal to the thickness t 1 of the first disc-like flange 1 and taper away from the flange, so as to be in the form of a trapezoid shape in section. The first disc-like flange 1 is preferably formed with a thickness three fifths to one half as large as the whole thickness H including thicknesses of the linear rib 4 and flange 1, resulting in the cycle time required for molding of the tape reel being reduced. Referring now to Fig. 5, a VHS top cassette in which a pair of the tape reels 10 of the illustrated embodiment each constructed as described above are adapted to be incorporated is illustrated by way of example. The tape cassette includes a casing formed by joining an upper casing member 11 and a lower casing member 12 to each other. The tape reels 10 are received in the casing and have a tape 13 wound thereon. The tape 13 is arranged so as to travel between the tape reels 10 in the casing while being guided through a front opening of the casing. The casing is pivotally provided on a front portion thereof with a front lid 14 so as to selectively cover the front opening of the casing and therefore a portion of the tape traveling through the opening. Also, the tape cassette includes a presser spring 15 for the tape reel 10, a pair of brake members 17 selectively engaged with respective lock gear 7 arranged on the tape reels 10, and an operation element 16. In the tape cassette thus constructed, the tape 13 is permitted to travel between the tape reels 10 for recording and reproduction. As can be seen from the foregoing, the tape reel of the present invention is constructed in such manner that the reinforcing ribs include the annular rib arranged on the outer periphery of the disc-like flange and a plurality of the linear ribs arranged on the outer surface of the disc-like flange so as to extend from the core stabilizing surface rib to the annular rib. Also, the linear ribs are so arranged that each of the linear ribs intersects at least one of the other linear ribs at a position which is outward of the midpoint between the core stabilizing surface rib and the annular rib. Such construction of the present invention substantially prevents deformation of the tape reel having a tape wound thereon, even when the flange is thin-walled to substantially shorten the tape reel molding cycle or reduce the period of time required for the molding step of the tape reel. Also, it effectively restrains deformation of the tape reel during storage thereof at high temperature. Further, it provides the tape reel with strength or rigidness sufficient to withstand stress applied thereto during taking-up of a tape thereon or storage thereof at an increased temperature, to thereby prevent deformation and/or deflection thereof. Moreover, it contributes to weight- and cost-savings of the tape reel, improves moldability thereof and permits it to exhibit increased reliability. While preferred embodiments of the invention have been described with a certain degree of particularity with reference to the accompanying drawings, obvious modifications and variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

Claims: A tape reel (10) for a tape cassette, comprising a reel hub (2) on which a tape (13) can be wound, a disc-like flange (1) molded integrally with said reel hub (2) and having an inner surface to receive the wound tape and an outer surface opposite from said inner surface, a core stabilizing surface rib (5) on said outer surface of said disc-like flange (1), a reinforcing annular rib (6) at the outer periphery of said disc-like flange (1) and a plurality of reinforcing linear ribs (4) on said outer surface of said disc-like flange (1) and extending from said core stabilizing surface rib (5) to said annular rib (6) characterised in that : said linear ribs (4) are so arranged that each of said linear ribs (4) intersects at least one of the other linear ribs (4) at a position (4 1 ) which is further from said core stablizing rib (5) than a midpoint between said core stabilizing rib (5) and said annular rib (5). A tape reel as defined in claim 1, wherein said linear ribs (4) are so arranged that each said linear rib (4) intersects said at least one of the other linear ribs (4) at a position (4 1 ) located on said annular rib (6). A tape reel as defined in claim 1 or 2, wherein said linear ribs (4) are so arranged that each said linear rib (4) intersects another one of said linear ribs (4) at a position (4 2 ) located on said core stabilizing surface rib (5). A tape reel as defined in any one claims 1 to 3, wherein said linear ribs (4) are so arranged that every two of said linear ribs (4) opposite to each other with said reel hub (2) being interposed therebetween are aligned with each other on a straight line. A tape reel as defined in claim 1, wherein said linear ribs (4) are so arranged that every two of said linear ribs (4) opposite to each other with said reel hub (2) being interposed therebetween are aligned with each other on a straight line; and said linear ribs (4) are so arranged that each said linear rib (4) intersects said at least one of the other linear ribs (4) at a position (4 1 ) located on said annular rib (6) and intersects another one of said linear ribs (4) at a position (4 2 ) located on said core stabilizing surface rib (5), whereby said linear ribs (4) in association with each other form a substantially star-like reinforcing rib structure. A tape reel as defined in any one of claims 1 to 5, wherein said linear ribs (4) are each formed with a base width (t 2 ) substantially equal to the thickness (t 1 ) of said flange (1) and taper away from said flange so as to be trapezoidal in section.

Inventors: KANEDA HIROSHI, OKAMURA MASATOSHI, UMEKI SADATOSHI, KANEDA, HIROSHI, OKAMURA, MASATOSHI, UMEKI, SADATOSHI
Applicants: TDK CORP, TDK CORPORATION
Application year: 1997
Main classification: G11B23
IPC codes: G11B23