Abstract:
A tape reel comprising a lower reel member consisting of a disc-like portion and a hub which are designed as an integral part, protrusions having claw-like heads formed on the end surface of said hub and a disc-like upper reel member, whereby said upper and lower reel members can be assembled and fixed to each other by fitting the protrusions formed on the hub into the holes formed in said upper reel member.

Description:
BACKGROUND OF THE INVENTION 
     a. Field of the Invention 
     The present invention relates to a tape reel and, more specifically, to a tape reel for use with a video cassette. 
     b. Description of the Prior Art 
     The conventional tape reel for use with a video cassette consists, as shown in FIG. 1, a lower reel member 1 having a hub 2 and an upper reel member 3 which are assembled with each other by fitting plural number of protrusions 2a formed on the hub 2 of the lower reel member 1 into holes formed in the number corresponding to that of said protrusions 2a in the upper reel member 3, and then fixed to each other by fixing the protrusions 2a by a means such as ultrasonic welding. 
     Such a conventional example had a defect that it requires a large number of manufacturing stages since welding of the upper and lower reel members is necessary after they have been assembled. Further, it had an additional defect that the reel members may be deformed at the welding stage, thereby making it impossible to manufacture tape reels with high precision. 
     SUMMARY OF THE INVENTION 
     A general object of the present invention is to provide a tape reel comprising a lower reel member consisting of a disc-like flange and a hub which are made integral and a disc-like upper reel member, said two members being fixed to each other by fitting protrusions having claw-like heads formed on either member into holes formed in the other member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a sectional view illustrating the construction of the conventional tape reel; 
     FIG. 2 shows a sectional view illustrating the construction of an embodiment of the tape reel according to the present invention; 
     FIG. 3 shows a sectional view illustrating the construction of another embodiment of the present invention; 
     FIG. 4 illustrates a plan view showing details of the construction of the lower reel member of the Embodiment 2; 
     FIG. 5 illustrates a plan view showing details of the construction of the upper reel member of the Embodiment 2; and 
     FIG. 6 illustrates a sectional view taken along VI--VI in FIG. 3. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the accompanying drawings, some preferred embodiments of the tape reel according to the present invention will be described. FIG. 2 shows a sectional view illustrating the constructions of the main parts in the Embodiment 1 of the present invention wherein shape of the protrusions formed on the hub is different from that of the conventional tape reel shown in FIG. 1. Speaking concretely, the embodiment is different from the conventional tape reel in that the former has claw-like heads 13a on the tops of the protrusions 13 on the hub 12 of the lower reel member 11. When the heads 13a of the protrusions 13 are forcibly fitted into the holes 14a of the upper reel member 14 which has the same shape as that of the conventional tape reel, the protrusions 13 are flexed and inserted, whereby heads 13a are engaged with the holes 14a of the upper reel member to fix both the reel members as shown in FIG. 2. FIG. 3 shows the Embodiment 2 of the present invention wherein the protrusions for fixing the upper and lower reel members are formed on the upper reel member. Speaking concretely, protrusions 15 are formed on the upper reel member 14&#39;, whereas holes to be engaged with the claw-like heads 15a of the protrusions 15 are formed in the cylindrical circumferential wall around the hollow portion 21 of the hub 17 of the lower reel member for inserting a driving shaft. The upper and lower reel members are assembled and fixed by inserting the protrusions into the holes to compose a tape reel in the procedures similar to those described with reference to the Embodiment 1. 
     In the Embodiment 2 shown in FIG. 3, groove 18 having a definite depth d is formed in the circumferential wall 17a with notch portion 19 left for fixing a tape as shown in FIG. 4, and slots 20 are further formed at constant intervals so as to form holes 22 which pass from the groove 18 to the hollow portion 21 of the hub 17 for inserting a driving shaft. When the upper and lower reel members are asembled with each other, the protrusions 15 of the upper reel member are inserted into the slots 20 and the heads 15a of the protrusions 15 are engaged with the holes 22, thereby fixing both the reel members to each other. 
     Thickness t 1  of the side 17b of the hub to be brought into contact with the upper reel member is larger than the thickness t 2  of the flange on the side of the reel. Therefore, the protrusions 15 of the Embodiment 2 are longer than the protrusions 13 in the Embodiment 1. In the embodiment 2, therefore the protrusions are flexed more easily and have lower possibility of breakage in assembling and fixing both the upper and lower reel members. In the Embodiment 2, it is not always necessary to form the groove as shown in FIG. 3, but will be sufficient to form holes for engaging the protrusions only at the portions for inserting the protrusions. When the reel members are manufactured by molding a synthetic resin, however, thick portions will be deformed and cannot be manufactured with high precision due to contraction of the resin at the molding stage. In order to correct this defect, it is generally practised to thin such portions, for example, by forming a groove as shown in FIG. 3. In the Embodiment 2 of the present invention, it is possible to form holes for fixing the upper and lower reel members very easily simply by forming the slots while utilizing the groove. Further, when three protrusions are formed on the upper reel member, it is preferable to form the corresponding holes 22 in vertically elongated slots 21a (refer to FIG. 3 and FIG. 6) which are formed on the side of the hollow portion 21 of the hub 17. Since a driving shaft has three protrusions within the range to be inserted into the hub, slots 21a are formed at the intermediate portion of the hub as shown in FIG. 6 for fitting the above-mentioned protrusions of the driving shaft. However, the driving shaft is a simple cylinder in the section from its intermediate point to the tip. When the holes are formed in the slots (generally three or its integral multiples), the heads of the protrusions engaged with the holes are not brought into contact with the driving shaft, thereby assuring advantage in practice. Shallow slots will be sufficient in such a construction. Furthermore, such a construction makes it possible to reserve a long distance longitudinally from the surface of the hub to be brought into contact with the upper reel member to the holes. This therefore permits protrusions 15 to be longer so that they can be flexed more easily. 
     As is clearly understood from the foregoing descriptions, the tape reel according to the present invention does not require welding or similar means for fixing the upper and lower reel members which instead can be assembled and fixed to each other simply by forcibly fitting protrusions formed on the upper or lower reel member in the holes formed in the other reel member so as to compose a tape reel. Therefore, the present invention can remarkably simplify the stage of assembling the reel members without fear of degradation of manufacturing precision due to deformation. The embodiment 2 of the present invention makes it possible to design longer protrusions which can be flexed larger and have lower possibility of breakage, thereby permitting fixing both the reel members more strongly.