GB2135653A - Computer tape reel - Google Patents

Abstract

A computer tape reel composed of separately fabricated front and rear reel flanges (22 and 24) and a hub (20). Radially arranged ribs and radially extending slots are provided on the flanges and hub which register with one another when the parts are assembled to establish concentricity. Welding heads are provided on the radially extending side surfaces of some of the ribs for shear welding the flanges and hub together. The hub consists of an inner mounting ring 26 and an outer winding ring 28 joined by a web 30, the rear surface of web 30 having a flange 50. Spaced radial ribs 36 extend on the front surface of web 30 between the rings and these ribs have a thickness not exceeding 60% of the outer ring thickness to prevent sink-marks occurring and to support the outer ring against high compression. Additional pairs of ribs 56 and further knock-out ribs 70 extend radially between the flange 50 and the rings. Radial ribs on the flanges fit between the ribs 36 and 56 on the hub. As many as 72 ribs may be provided, spaced at 5 DEG apart. The flat surfaces 38, 40, 126 of the flanges which contact the ends 54 of the hub are free of welding beads. The hub may be moulded of glass filled styrene and the flanges of styrene. <IMAGE>

Description

SPECIFICATION Computer Tape Reel This invention relates to tape reels and more particularly comprises a new and improved computer tape reel having a hub of high compressive strength and features which ensure concentricity of the reel flanges and hub.

When computer tape is wound on a reel, the hub is subjected to compressive forces which are a a function of the tape tension. During the past ten or fifteen years, industry standards have been rather constant in prescribing the compressive strength requirements of the hub. The standards have been established in terms of hub diameter when the reel is fully loaded with tape wound at a prescribed tension.

Very recently increased drive speeds utilized in computers have significantly raised the winding tension, and consequently greater compressive loads are now being imposed. One important object of this invention is to provide a hub configuration which is capable of withstanding the higher compressive loads so as to maintain the minimum hub diameter.

Industry standards also prescibe the reel flange dimensions, but the manner of attaching the flanges to the hub is left to the choice of the manufacturer. It is, however, essential that the reel flanges be concentric with the hub. Most commonly, this has been accomplished by fitting a ring molded on each of the flanges into rings molded on the hub and matching the mating diameters. Because it is impossible to consistently mold parts to precisely the same dimensions, the rings have been molded either with excess clearance in which case concentricity has been sacrificed, or the rings have been molded with an interference fit, in which case stresses have been created that have tended to warp the reel flanges.

The warping of the flanges is also an unacceptable condition because industry standards prescribe that thc flatness be held within certain tight tolerances. Another important object of this invention is to provide means for securing the reel flanges to the hub, which insures concentricity.

It is universal practice in the industry to ultrasonically weld the reel flanges to the hub after the parts are separately molded. This is normally accomplished by molding welding beads on the parts, which beads melt with ultrasonic energy to form a bond between the parts. Most commonly, the beads are provided on the areas of the reel flanges which abut against the ends of the winding ring of the hub. This method has several disadvantages. While the separation between the inner surfaces of the reel flanges is a critical dimension, that dimension is very difficult to control since it varies with the amount of melt between the hub winding ring and the flanges. If the melt is not very precisely controlled, the flanges can toe in or out.

Yet another disadvantage of this compressiontype of ultrasonic welding is that it is only capable of providing a strong molecular bond when parts of identical material are welded together. If the parts are of different materials which have different melt temperatures, true molecular bonds are seldom achieved.

Another important object of this invention is to provide means for securing the reel flanges and hub together, which eliminates the need for welding beads on the mating surfaces of the winding ring of the hub and the flanges so as to insure that the winding path is the prescribed critical width.

Yet another important object of this invention is to employ a welding technique which is suitable for securing the hub and reel flanges together when they are made of dissimilar materials.

To accomplish these and other objects, the computer tape reel of the present invention in its preferred embodiment includes a hub made of glass filled styrene. The hub has inner and outer cylindrically shaped rings joined by a solid web.

The inner surface of the inner ring serves as the drive mounting surface of the reel while the outer surface of the outer ring is the winding surface for the tape. A number of radial ribs extend between the inner and outer rings on the front and back sides of the web to increase the compressive strength, dimensional stability and rigidity of the hub. The ribs on the front side of the hub extend the full distance between the rings, and on the rear side an intermediate hub flange is provided which is parallel to the inner and outer rings.

Strengthening ribs on the rear side are provided between the hub flange and the outer ring to further stiffen and strengthen the hub. Knockout ribs are also provided between the hub flange and the inner ring on the rear side. The knockout ribs are axially aligned with the ribs on the front of the hub.

The ribs on the front and rear of the hub cooperate with ribs provided on the inner surfaces of the reel flanges, and certain of the ribs define radial slots which receive ribs on the mating parts to insure concentricity of the reel flanges and hub when the three parts are assembled.

The ribs are provided with welding beads on their mating surfaces, and shear welding is employed to produce the molecular bond between the parts. The shear welding technique is particularly suitable when the reel hub and flanges are made of dissimilar material.

These and other objects and features of the invention will be better understood and appreciated from the following detailed description, read in connection with the accompanying drawings.

Fig. 1 is a front elevation view of a computer tape reel constructed in accordance with this invention; Fig. 2 is a side elevation view of the reel of Fig.

1; Figs. 3 and 4 are fragmentary cross-sectional views of the reel taken along the section lines 33 and 4-4 in Fig. 1 and showing the manner in which the hub and reel flanges are assembled; Fig. 5 is a fragmentary view of the rear side of the front reel flange of the reel; Fig. 6 is a fragmentary cross sectional view of the front reel flange taken along section line 6-6 in Fig. 5; Fig. 7 is a fragmentary view of the front side of the hub which mates with the rear side of the front flange shown in Fig. 5; Fig. 8 is a fragmentary cross sectional view of the hub taken along section line 8-8 in Fig. 7; Fig. 9 is a fragmentary view of the rear side of the hub;; Fig.10 is a fragmentary view of the front side of the rear flange of the reel which mates with the rear side of the hub shown in Fig. 9; and Fig. 11 is a cross sectional view of the rear reel flange taken along section line 11-1 in Fig. 10.

The reel of the present invention is made up of three separate parts, namely, a hub 20, front reel flange 22 and rear reel flange 24. Each of the three parts is described separately below, and thereafter the manner in which they are assembled together to form the completed reel is presented.

Hub (Figs. 3, 4 and 7-9) Hub 20 includes an inner mounting ring 26 and an outer winding ring 28, both of which are cylindrical in shape and joined together by a web 30. In its preferred form, the hub is made of a glass-filled styrene and is manufactured on conventional injection-molding equipment.

The inner surface 32 of inner ring 26 is designed to be mounted on the drive of the computer equipment on which the reel is used, and the outer surface 34 of outer ring 28 serves as the winding surface on which the computer tape is wound.

The front side of the inner and outer rings 26 and 28 on the upper side of web 30 as viewed in Fig. 3 are joined by a number of closely-spaced radially oriented ribs 36 (see Fig. 7) provided with shoulders 38 at their inner radial edges. The shoulders 38 cooperate with the front end face 40 of the outer ring 28 to define a platform against which the front reel flange 20 is supported. Each rib 36 is somewhat shorter than the front side of outer ring 28 so as to form a slight clearance between the rear face of the front reel flange and the ribs, to insure a stable platform for the reel flange on shoulder 38 and surface 40.

A generally cylindrical hub flange 50 is disposed on the rear side of web 30 and lies intermediate the inner and outer rings 26 and 28.

The height of the flange 50 is precisely equal to the height of the rear side of ring 28 so that the rear surface 52 of the flange and the rear end surface 54 of the ring 28 lie in a common plane precisely perpendicular to the winding surface 34.

An array of closely spaced ribs 56 arranged in pairs extend essentially radially between the outer ring 28 and the flange 50, and their rear surfaces 58 lie below the plane of the surfaces 52 and 54 so as to form a clearance between the ribs 56 and the rear reel flange 24. Each pair of ribs 56 defines a narrow slot 60 between them, which slots are designed to receive mating ribs on the rear reel flange when the reel is assembled. The slots 60 are defined by the facing surfaces 62 of the ribs 56, and a number of welding beads 64 are provided on the surfaces 62 to develop the molecular bond between the ribs 62 and the mating ribs on the rear reel flange 24 as is more fully described below.

A number of knockout ribs 70 are provided on the rear face of the web 30 between the inner ring 26 and the flange 50. The ribs 70 are enlarged at 72 intermediate the inner and outer radial ends so as to provide a large bearing surfaces for the knockout pins in the mold used to form the hub. It will be noted in Fig. 8 that the knockout ribs 70 are axially aligned with the ribs 36 on the front side of web 30. The alignment of the knockout ribs 70 with the ribs 36 on the front side of the web allows the knockout pins of the mold to push against a supported wall.

In selecting the various dimensions for the ribs and rings of the hub, the thickness of the ribs should be no more than 60% of the thickness of the outer winding ring 26 to insure that no sink marks are created on the outer winding surface 34, which would produce imperfect tape winding characteristics. In the preferred embodiment, the thickness of the winding ring is .125 inch which provides adequate ring strength. Increasing the ring thickness would, of course, greatly increase the cost of the part and would also increase the molding cycle. In the preferred embodiment, the rib thickness selected is .050 inch plus a slight draft, which is less than the 60% of the outer ring thickness and yet provides the strength necessary. Also in the preferred embodiment, 72 ribs have been provided five degrees apart, which was considered a practical maximum.

Front Flange (Figs. 1 and 3-6) The front flange 22 is annular in shape and has an inner edge 80 and outer edge 82. When the flange is mounted on the hub, the inner edge 80 of the front flange lies just outside the outer face 84 of inner mounting ring 26. The flange carries a pair of concentric decorative beads 86 and 88 and a finger grip 90 to assist in rotating the assembled reel. The inner face 92 of the outer flange 22 is provided with a very shallow recess 94 adjacent its inner edge 80 where the reel flange is supported on the hub. This feature is clearly shown in Fig. 3.

A plurality of pairs of radial ribs 100 are formed perpendicular to the inner face 92 of the front flange 22 on the recessed surface 94. The ribs define a slot 102 between each pair, which slot is very slightly larger than the width of the ribs 36 on the front side of hub 20. In the preferred form of the invention, the center lines of the slots 1 02 are spaced 10 degrees apart so that every other rib 36 on the front face of hub 20 is received in a slot on the front flange when the parts are assembled. In the embodiment shown, a number of welding beads 104 are formed on the facing surfaces 106 of the ribs 100 which as described in detail below, bond the ribs 100 to the ribs 36 of the hub during the shear welding operation.

As shown in Fig. 3, the flange 22 is positioned in place on the hub against the end faces 38 and 40, and the pairs of ribs 100 of the front flange straddle alternate ribs 36 of the hub. The welding beads 104 engage the large side faces of the ribs 36 so as to provide a very large surface area for the molecular bonding of the parts. The main supporting surfaces 38 and 40 for the front flange 22 are free of beads but rather provide a firm and precise supporting surface.

In the embodiment shown the ends of the ribs 100 are shown enlarged so as to increase their strength. The enlargements are not an essential feature of the invention, and may be dispensed with.

In the preferred embodiment the space 102 between the pairs of ribs 100 is approximately .056 inch with a three percent draft, while the ribs 36 are .050 inch with a three percent draft on the sides. The ribs 100 are approximately .070 inch in width.

Rear Flange (Figs. 1,3, 4, 10 and 11) Rear flange 24 like front flange 22 carries a pair of decorative concentric beads 1 20 and 122, and its inner surface 124 is provided with a shallow recess 126 that bears against the outer surfaces 52 and 54 of the hub flange 50 and outer winding ring 28 when the rear flange is assembled on the hub. A plurality of radial ribs 130 are molded on the surface 1 24 of the rear flange 24 within the recess 126, and in the preferred embodiment the ribs 130 are spaced 10 degrees apart so as to lie within the recesses 60 formed by the ribs 56 on the rear side of the hub between the intermediate flange 50 and outer winding ring 28. The manner in which the ribs 130 fit between the ribs 56 and their welding beads 64 is clearly illustrated in Figs. 3 and 4.The ribs 130 are approximately .080 inch in width and are provided with a 2% draft along the sides. This width is very slightly smaller than the width .086 inch of slots 60 so that the parts may be assembled in the manner shown.

Between the radial ribs 130 are posts 136 which are reinforced by ears 138 as shown in Fig.

10. The posts 136 bear the force of the knock-out pins in the mold when the rear flange is ejected, and they do not serve any important structural function when the flange 24 is assembled on the hub. Thus, there function is in the manufacturing step of the rear flange and they serve no purpose after the reel is assembled. It will be noted, however, that when the rear flange 24 is assembled on the hub, the posts 36 and their reinforcements 138 lie in the recesses 140 formed on the rear side of hub 20 between the pairs of ribs 56. This arrangement is shown in Fig.

4.

Assembly As is described in the introduction, it is customary in the prior art to assemble the flanges and hub together by ultrasonic welding. This is ordinarily accomplished by molding welding beads on one part which melts with ultrasonic energy to form a bond with the other part to which it is to be attached. Most frequently, the welding beads are provided between the supporting surfaces at the ends of the winding ring which engage the reel flanges. This method has several disadvantages. The distance between the flanges that define the tape path is a critical dimension, and it is difficult to control since it varies with the amount of melt of the beads on the contacting surfaces. If there is too much melt, the tape path is narrowed below the critical acceptable dimension, and if there is insufficient melt, the tape path will be wider than prescribed.

The melt may also cause the flanges to tow in or tow out. This type of weld provides a strong molecular bond only when identical materials are being welded together. When the hub is made of a different material than the flanges, such as a glass-filled styrene hub and styrene flanges, the hub has a higher melt temperature than the flanges, and a true molecular bond is seldom achieved. A superior weld for dissimilar materials is achieved by shear welding. In accordance with this invention, the radial ribs on the flanges and hub lend themselves to this type of welding.

As described above, the surface 62 of ribs 56 that define the slots 60 on the rear side of the hub carry welding beads 64, and similar beads 104 are provided on the surfaces 106 of the ribs 100 that define the slots 102 on the front flange 22.

Those surfaces on which the beads are molded provide a very large area for the melt to form the molecular bond. It will also be appreciated that to separate the parts, the bond must fail in shear rather than in direct tension as is the case when conventional welding is used. The large number of ribs provided in the assembly define an enormous bonding area that is utilized in the present invention.

Shear welding is particularly effective in the present invention in forming a bond between the glassed-filled styrene hub and the solid styrene flanges because of the considerable relative movement between the ribs during welding. As the tapered ribs are subjected to the ultrasonic vibrations, the beads melt and the ribs move with respect to one another as suggested by the arrows 142 in Fig. 4. This causes the materials of both the flanges and the hub to roll together, which forms a particularly strong glass-filled melt to create a strong physical bond. And since there are no welding beads on the mating surfaces, the hub itself can be used as a fixture to control the tape path dimensions. When flat surfaces come together in welding, there is no significant melt or change of dimension.

From the foregoing description those skilled in the art will appreciate that the many objects of this invention enumerated in the introduction are achieved by the present invention. Concentricity is achieved even with small variations in the part sizes because of the configuration of the matching radial ribs. An extremely strong bond between the hub and reel flanges is developed because of the greatly increased weld melt area on the vertical surfaces of the ribs and the rolling together of the dissimilar materials during welding. Furthermore, the reel flanges remain flat as there are no transfer of stresses between mating annular rings, which is found in the prior art. And the critical dimensions are maintained because of the lack of melt on matching flat surfaces.

Because numerous modifications may be made of this invention without departing from its spirit, it is not intended to limit the breadth of this invention to the single embodiment illustrated and described. Rather, the scope of this invention is to be determined by the appended claims and their equivalents.

Claims (23)

1. A computer tape reel comprising a hub having inner and outer rings joined by a web, reel flanges at the ends of the outer ring and extending radially inwardly of the outer ring, and arrays of radial slots and radial ribs formed on the surfaces of the web and reel flanges which face one another and cooperating with one another to establish concentricity between the reel flanges and hub, said reel flanges and hub being free of rings molded on the hub and mating rings on the flanges to provide concentricity.

2. A computer tape reel as claimed in claim 1 having welding beads on at least some of the facing surfaces on the slots and ribs for shear welding the flanges and hub together.

3. A reel comprising a hub having front and rear sides, reel flanges mounted on the front and rear sides of the hub, connecting means joining the reel flanges and hub, said connecting means joining at least one of the reel flanges and hub including means defining slots on either the hub or said one flange and ribs on the other of said hub or one flange, said slots and ribs being disposed angularly with respect to their other like parts and cooperating to concentrically align said one flange and said hub, said flanges being free of circular rings engaging the hub which interfere with the ribs and slots establishing their concentric alignment.

4. A hub for a computer tape reel comprising a circular inner mounting ring for engaging a tape drive spindle and a circular outer winding ring for tape spaced apart and parallel to one another, an array of spaced radially oriented ribs about the circumference of the hub and joining the inner and outer rings for supporting the outer winding ring and resisting compressive loads applied to the outer ring, said ribs having a thickness not exceeding 60% of the outer winding ring thickness, and welding beads formed on the sides of the radial ribs for engaging the sides of radially elongated ribs on a mating reel flange for shear welding the hub and flange together.

5. A hub as defined in claim 4 further characterized by a hub flange disposed between and parallel to the rings, a plurality of pairs of additional ribs arranged radially and connecting the winding ring and flange, said pairs of ribs being spaced apart and arranged circumferentially about the hub for receiving radially elongated ribs of a second reel flange to position that flange concentrically with respect to the hub and for resisting compressive loads applied to the winding ring.

6. A hub as defined in claim 5 further characterised by yet additional ribs connecting the flange and mounting ring and aligned with the spaces between the pairs of ribs.

7. A computer reel comprising a hub having generally parallel inner and outer rings and a connecting web, the inner ring being adapted to support the reel on a reel drive and the outer ring being adapted to have the tape wound about its outer surface, one side of the web facing the front of the reel and the other side of the web facing the rear of the reel, pairs of ribs mounted between the rings on one side of the web, said pairs of ribs defining radially extending elongated slots between them with the slots being arranged angularly with respect to one another, and a reel flange engaging one end of the outer ring, said reel flange having radially elongated ribs that fit into the slots, said ribs on the flange and said slots on the hub cooperating to establish the concentric alignment of the flange and hub with respect to one another.

8. A computer reel as defined in claim 7 further characterised by ultrasonic shear welds permanently joining the sides of the ribs on the flange with the sides of the ribs on the hub that define the radial slots.

9. A computer reel as defined in claim 7 or claim 8 including reel flanges mounted on the front and rear sides of the hub and engaging the opposite ends of the winding ring, and connecting means joining the reel flanges and hub, said connecting means including elongated radial surfaces defining radial slots on either the hub or flanges and ribs having elongated radial surfaces on the other of the flanges and hub and fitting within the slots, said radial surfaces of the ribs and slots cooperating to establish concentric alignment of the reel flanges and hub, and ultrasonic shear welds on the radial surfaces permanently joining the radial surfaces of the. ribs and slots together, said reel flanges being free of circular rings engaging the inner and outer rings of the hub to interfere with the establishnient of the concentric alignment by the radial surfaces.

10. A reel as defined in claim 9 further characterised by said reel hub being molded of glass filled styrene and said reel flange being molded of styrene, and welding beads being provided on the surfaces of at least some of the ribs and slots for making the shear welds.

11. A reel as defined in claim 10 further characterised by flat surfaces being provided on the ends of the winding ring and flat surfaces being provided on the reel flanges where they engage the ends of the winding ring, said flat surfaces being free of welding beads.

12. A reel as defined in claim 9 further characterised by ribs on the front side of said hub supporting the outer ring against compressive loads applied by tape wound on the reel.

13. A reel as defined in claim 12 further characterised by said ribs on the front side of the hub being equidistantly spaced about the hub.

14. A reel as defined in claim 9 further characterised by ribs on the rear side of the web on the hub being arranged in pairs and providing the surfaces defining the slots.

15. A reel as defined in claim 9 further characterised by a flange being formed as part of the hub on the rear side of the web and disposed between the rings, and ribs on the rear side of the web connecting the winding ring and hub flange.

16. A reel as defined in claim 15 further characterised by the ribs on the rear side of the web on the hub being arranged in pairs and providing the surfaces defining the slots.

17. A reel as defined in claim 16 further characterised by knockout ribs provided on the rear side of the web between the mounting ring and hub flange and radially aligned with the slot between the pairs of ribs mounted on the web between the winding ring and reel flange.

18. A reel as defined in claim 17 further characterised by said knockout ribs on the rear side of the web being axially aligned with the ribs on the front side of the web.

19. A reel as defined in claim 18 further characterised by said reel hub being molded of glass filled styrene and said reel flanges being molded of styrene, and welding beads being provided on the sides of at least some of the ribs for bonding them together.

20. A reel as defined in claim 19 further characterised by flat surfaces being provided on the ends of the winding ring and flat surfaces being provided on the reel flanges where they engage the ends of the winding ring, said flat surfaces being free of welding beads.

21. A reel comprising a hub having front and rearsides, reel flanges mounted on the front and rear sides of the hub, and connecting means joining the reel flanges and hub, said connecting means including elongated radial surfaces defining radial slots on either the hub or flanges and ribs having elongated radial surfaces on the other of the flange and hub and fitting within the slots, said radial surfaces of the ribs and slots cooperating to establish concentric alignment of the reel flanges and hub, and ultrasonic shear welds on the radial surfaces permanently joining the surfaces together.

22. A reel as defined in claim 21 further characterised by said slots and ribs being equidistantly spaced and being concentric with the hub and flanges.

23. A computer tape reel substantially as hereinbefore described with reference to the accompanying drawings.