Patent Publication Number: US-2005139708-A1

Title: Tape reel assembly with wear resistant driven teeth

Description:
THE FIELD OF THE INVENTION  
      The present invention relates to a tape reel assembly for a data storage tape cartridge. More particularly, it relates to a tape reel assembly having wear resistant driven teeth.  
     BACKGROUND OF THE INVENTION  
      Data storage tape cartridges have been used for decades in the computer, audio, and video fields. The data storage tape cartridge continues to be a popular device for recording large volumes of information for subsequent retrieval and use.  
      A data storage tape cartridge generally consists of an outer shell or housing maintaining at least one tape reel assembly and a length of magnetic storage tape. The storage tape is wrapped about a hub portion of the tape reel assembly and is driven through a defined path by a tape drive system. The housing normally includes a separate cover and a separate base. Together, the cover and base form an opening (or window) at a forward portion thereof permitting access to the storage tape by a read/write head upon insertion of the data storage tape cartridge into a tape drive. The interaction between the storage tape and head occurs within the housing for a mid-tape load design. Conversely, the interaction between the storage tape and head occurs exterior the housing where the read/write head is annexed for a helical drive design. Where the tape cartridge/drive system is designed to direct the storage tape away from the housing, the data storage tape cartridge normally includes a single tape reel assembly employing a leader block design. Alternately, where the tape cartridge/drive system is designed to provide head/storage tape interaction within the housing, a dual tape reel configuration is typically employed.  
      Regardless of the number of the tape reel assemblies associated with a particular data storage tape cartridge, the tape reel assembly itself is generally comprised of three elements: an upper flange, a lower flange, and a hub. The hub forms a tape-winding surface about which the storage tape is wound. The flanges are disposed at opposite ends of the hub and spaced apart to accommodate a width of the storage tape. To reduce the likelihood of the storage tape undesirably contacting one of the flanges during a winding operation, the flange-to-flange spacing is selected to be slightly greater than the width of the tape.  
      Reading information from, or writing information to, the storage tape requires the tape reel assembly to be rotated such that a desired portion of the storage tape can be located and accessed by a read/write head. To this end, the cartridge is inserted into the tape drive with the read/write head. The tape drive rotates the tape reel assembly, thereby driving the tape across the read/write head. To facilitate this operation, tape reel assemblies have driven teeth suited for engagement by a drive chuck of the tape drive. The drive chuck engages the driven teeth of the tape reel assembly (known as “chuck-up”) and rotates (i.e., drives) the tape reel assembly to wind/unwind the data storage tape. Significantly, the drive chuck is typically formed of a hardened material, often metal. Consequently, the drive chuck can cause the driven teeth to wear.  
      Tape reel assemblies are typically formed from plastic components. Plastic driven teeth, though cost effective, can be ablated by the drive chuck. As the driven teeth wear down, debris is created. The debris from the driven teeth can be spread throughout the tape drive system. In particular, debris spread to the data storage tape can interfere with the reading and writing of information to the data storage tape. In addition, frequent access to the information stored on the data storage tape necessitates frequent tape reel assembly/drive chuck interaction, leading to increased debris generation. Eventually, debris from worn driven teeth can contribute to cartridge loading failures, read/write errors, and other system problems.  
      Data storage tape cartridges are useful tools for collecting and protecting information stored on data storage tape. However, the driven teeth of the tape reel assembly are vulnerable to wear when repeatedly engaged by the drive chuck of the tape drive system. In particular, plastic driven teeth create debris as they wear. To this end, debris generation during tape reel/tape drive engagement can create errors in reading from, and writing to, the storage tape. Therefore, a need exists for a tape reel assembly having wear resistant driven teeth.  
     SUMMARY OF THE INVENTION  
      One aspect of the present invention relates to a tape reel assembly for a data storage tape cartridge. The tape reel assembly includes a hub defining a tape-winding surface and driven teeth defining an engagement surface. In this regard, the driven teeth are formed from a polymer including a lubricating additive.  
      Another aspect of the present invention relates to a data storage tape cartridge. The data storage tape cartridge includes a housing defining an enclosed region, at least one tape reel assembly, and a storage tape. The tape reel assembly is rotatably disposed within the enclosed region and includes a hub defining a tape-winding surface and driven teeth defining an engagement surface. In this regard, the driven teeth are formed from a polymer including a lubricating additive.  
      Yet another aspect of the present invention relates to a method of fabricating a tape reel assembly for a data storage tape cartridge. The method includes providing a polymer including a lubricating additive. The method additionally includes forming driven teeth defining an engagement surface from the polymer. The method ultimately includes generating a hub to which the driven teeth are connected.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Embodiments of the invention are better understood with reference to the following drawings. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts.  
       FIG. 1  is a perspective, exploded view of a single reel, data storage tape cartridge in accordance with the invention showing a tape reel assembly;  
       FIG. 2  is an exploded view of a tape reel assembly including a flange with driven teeth according to one embodiment of the present invention;  
       FIG. 3  is a cross-sectional view of the flange shown in  FIG. 2 ;  
       FIG. 4  is a cross-sectional view of a tape drive system including the cartridge of  FIG. 1  according to one embodiment of the present invention;  
       FIG. 5  is an exploded view of a tape reel assembly including a hub having driven teeth according to another embodiment of the present invention; and  
       FIG. 6  is a cross-sectional view of the hub shown in  FIG. 5 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      An exemplary single reel data storage tape cartridge according to one embodiment of the present invention is illustrated at  20  in  FIG. 1 . Generally, the data storage tape cartridge  20  includes a housing  22 , a brake assembly  24 , a tape reel assembly  26 , a storage tape  28 , and a leader block  30 . The tape reel assembly  26  is disposed within the housing  22 . The storage tape  28 , in turn, is wound about the tape reel assembly  26  and includes a leading end  32  attached to the leader block  30 . As a point of reference, while a single reel data storage tape cartridge  20  is shown, the present invention is equally applicable to other cartridge configurations, such as dual reel cartridges.  
      The housing  22  is sized for insertion into a typical tape drive (not shown). Thus, the housing  22  exhibits a size of approximately 125 mm×110 mm×21 mm, although other dimensions are equally acceptable. With this in mind, the housing  22  is defined by a first housing section  34  and a second housing section  36 . In one embodiment, the first housing section  34  forms a cover and the second housing section  36  forms a base. As used throughout the specification, directional terminology such as “cover,” “base,” “upper,” “lower,” “top,” “bottom,” etc., is employed for purposes of illustration only and is in no way limiting.  
      The first and second housing sections  34  and  36 , respectively, are sized to be reciprocally mated to one another to form an enclosed region  37  and are generally rectangular, except for one corner  38  that is preferably angled and forms a tape access window  40 . The tape access window  40  serves as an opening for the storage tape  28  to exit from the housing  22  such that the storage tape  28  can be threaded to a tape drive system (not shown) when the leader block  30  is removed from the tape access window  40 . Conversely, when the leader block  30  is stowed in the tape access window  40 , the tape access window  40  is covered.  
      In addition to forming a portion of the tape access window  40 , the second housing section  36  also forms a central opening  42 . The central opening  42  facilitates access to the tape reel assembly  26  by a drive chuck of the tape drive (not shown). During use, the drive chuck enters the central opening  42  to disengage the brake assembly  24  prior to rotating the tape reel assembly  26  for access to the storage tape  28 . The brake assembly  24  is of a type known in the art and generally includes a brake body  44  and a spring  46  co-axially disposed within the tape reel assembly  26 . When the data storage tape cartridge  20  is idle, the brake assembly  24  is engaged with a brake interface  48  to selectively “lock” the single tape reel assembly  26  to the housing  22 .  
      The storage tape  28  is preferably a magnetic tape of a type commonly known in the art. For example, the storage tape  28  may consist of a balanced polyethylene naphthalate (PEN) based material coated on one side with a layer of magnetic material dispersed within a suitable binder system and coated on the other side with a conductive material dispersed within a suitable binder system. Acceptable magnetic tape is available, for example, from Imation Corp., of Oakdale, MN.  
      The leader block  30  covers the tape access window  40  during storage of the cartridge  20  and facilitates retrieval of the storage tape  28  for read/write operations. In general terms, the leader block  30  is shaped to conform to the window  40  of the housing  22  and to cooperate with the tape drive (not shown) by providing a grasping surface for the tape drive to manipulate in delivering the storage tape  28  to the read/write head. In this regard, the leader block  30  can be replaced by other components, such as a dumb-bell shaped pin. Moreover, the leader block  30 , or a similar component, can be eliminated entirely, as is the case with dual reel cartridge designs.  
      The present invention, as more fully described below, is beneficially employed in cartridges with either a single tape reel assembly or a multiple tape reel assembly design. With this in mind, and with reference to  FIGS. 1 and 2 , the tape reel assembly  26  comprises a hub  50 , an upper flange  52 , a lower flange  54 , and driven teeth  56 . The upper and lower flanges  52 ,  54  extend in a radial fashion from opposing sides of the hub  50 , respectively. The driven teeth  56  can be disposed on (or formed by) the hub  50  or the lower flange  54 , as described below.  
       FIG. 2  is an exploded view of the tape reel assembly  26  shown in  FIG. 1 . The tape reel assembly  26  includes the hub  50  positioned between the upper flange  52  and the lower flange  54 . As illustrated, the lower flange  54  includes the driven teeth  56 . In one embodiment, the tape reel assembly  26  further includes a metallic washer  60 . The lower flange  54  can be molded about the washer  60 , or the washer  60  can be separately assembled to the lower flange  54 . Regardless, the washer  60  is adapted to magnetically couple the tape reel assembly  26  to a magnet within the tape drive (not shown).  
      The hub  50  includes a core  70  and defines an interior surface  72  and a tape-winding surface  74 . The tape-winding surface  74  is configured for acceptance of the data storage tape  28  ( FIG. 1 ). In this regard, the tape-winding surface  74  is located between a first end  76  and a second end  78  of the hub  50 . The upper flange  52  couples to the first end  76  of the hub  50  via an interior edge  80 . The lower flange  54  couples to the second end  78  of the hub  50  via a crown, as best illustrated in  FIG. 3  below.  
      With additional reference to  FIG. 3 , the lower flange  54  includes the driven teeth  56  that define an engagement surface  84 . In addition, the lower flange  54  defines an axial bore  86  about which the washer  60  is disposed. In this regard, the axial bore  86  is centrally located within the lower flange  54 . Further, the lower flange  54  includes a crown  88  configured to couple with the second end  78  of the hub  50  such that upon final assembly, the lower flange  54  extends in a radial fashion from the hub  50 . In the embodiment of  FIG. 3 , the lower flange  54  and the driven teeth  56  are integrally formed. To this end, the material employed to form the lower flange  54  and the driven teeth  56  is a polymer including a lubricating additive. In particular, the polymer imparts stiffness to the flange  54  and the lubricating additive lubricates the driven teeth  56  such that they resist wear when engaged by the drive chuck of the tape drive (not shown).  
      The lubricating additive can be any melt processable additive that reduces the abrasion between the driven teeth  56  and the drive chuck (not shown). Suitable lubricating additives include, but are not limited to, silicones, waxes, polytetrafluoroethylene, fluoroploymers, fluorochemicals, and oils. The lubricating additive can be compounded into the polymer, or alternately, the lubricating additive can simply be blended into the polymer. In any regard, the lubricating additive is melt processable and serves to increase the lubricity of the driven teeth  56  and the engagement surface  84 .  
      The lubricating additive is preferably added to the polymer in the range of 0.5 to 25% by weight, more preferably, the lubricating additive is added to the polymer in the range of 2-10% by weight, and most preferably the lubricating additive is added to the polymer at 5% by weight.  
      In a preferred embodiment, the driven teeth  56  are formed from a polymer including a glass-filled polycarbonate and polytetrafluoroethylene as a lubricating additive added at up to 25% by weight. For example, it has been advantageously discovered and described herein that driven teeth  56  formed from a polymer including 20% glass-filled polycarbonate and 5% polytetrafluoroethylene will resist wear associated with more than 10,000 engagements with the drive chuck (not shown).  
      After formation of the tape reel assembly  26 , the lubricating additive resides in the driven teeth  56  and is present on the engagement surface  84  of the lower flange  54 . In one embodiment, the driven teeth  56  are formed from a polymer including glass-filled polycarbonate for stiffness and a lubricating additive for abrasion resistance (i.e., lubricity). In particular, the lubricating additive in the driven teeth  56  and present on the engagement surface  84  permits thousands of couplings of the tape reel assembly  26  to the drive chuck (not shown) without appreciable wear being imparted to the driven teeth  56 . The lubricated driven teeth  56  according to the present invention generate much less debris than conventional driven teeth, and contribute to error free loading of the data storage tape cartridge  20  ( FIG. 1 ) into the tape drive.  
      The data storage tape cartridge  20  including the tape reel assembly  26  is shown in a final, assembled form in  FIG. 4 . For ease of illustration, the storage tape  28  ( FIG. 1 ) has been omitted from the view of  FIG. 4 . As previously described, the brake assembly  24  and the tape reel assembly  26  are disposed within the enclosed region  37  defined by the housing  22 . In this regard, the central bore  86  defined by the lower flange  54  is axially aligned with the opening  42  in the second housing section  36 . Further, the brake body  44  is disposed adjacent the inner surface  72  of the hub  50 . The spring  46  is similarly disposed co-axially with the brake body  44 . With this configuration, the spring  46  urges the brake body  44  into a locked position relative to the tape reel assembly  26 . In this locked position, the brake body  44  engages the brake interface  48  of the tape reel assembly  26 . The brake body  44  effectively rigidly connects the tape reel assembly  26  to the housing  22 , thereby preventing unexpected rotation of the tape reel assembly  26  relative to the housing  22  when in the locked position.  
      As a point of reference, the data storage tape cartridge  20  is shown in  FIG. 4  as part of a tape drive system  100 . The tape drive system  100  includes the data storage tape cartridge  20  and a tape drive  102 . The tape drive  102  includes a motor  104  (shown schematically) and a drive chuck  106 . The drive chuck  106  is rotatably driven by the motor  104  and includes engagement teeth  108  and a spindle  110 . In particular, the engagement teeth  108  are connected to the spindle  110 , with the spindle  110  terminated at a rounded tip  112 . In a preferred embodiment, the drive chuck  106  includes a magnet  114  that attracts the washer  60  of the tape reel assembly  26  during chuck-up of the data storage tape cartridge  20  with the tape drive  102 .  
      Reading or writing information to the storage tape  28  ( FIG. 1 ) is accomplished by the tape drive system  100 . The data storage tape cartridge  20  is inserted into the tape drive  102 . The tape drive system  100  causes the spindle  110  to disengage the brake assembly  24  such that the drive chuck  106  engages with the tape reel assembly  26  immediately thereafter. More particularly, as shown in  FIG. 4 , the rounded tip  112  of the spindle  110  guides the brake body  44  out of the locked position. The movement of the spindle  110  (upward relative to the orientation of  FIG. 4 ) overcomes the bias of the spring  46 , causing the brake body  44  to disengage from the brake interface  48  of the tape reel assembly  26 . The drive chuck  106  continues upward into the central opening  42  until the magnet  114  couples with the washer  60 , after which the engagement teeth  108  of the drive chuck  106  engage the driven teeth  56  of the tape reel assembly  26 . Ultimately, the magnet  114  attracts the washer  60  to ensure proper alignment of the tape reel assembly  26  with the tape drive  102 .  
      After the cartridge  20  is engaged in the tape drive  102 , the drive chuck  106 , when rotated by the motor  104 , rotates the tape reel assembly  26 . During some read/write operations, the tape reel assembly  26  can be rotated at speeds on the order of 2000 RPM or more to achieve data storage tape  28  ( FIG. 1 ) speeds on the order of 10 meters per second.  
      Cartridge loading failures are characterized by a rejection of the data storage tape cartridge by the tape drive, thus interfering with the reading and writing of data to the data storage tape. In accordance with the present invention, an improved tape reel assembly is disclosed having wear resistant driven teeth that enable more than 10,000 insertions of the cartridge  20  into the tape drive  102  without a loading failure. In particular, during use, the tape reel assembly  26  maintains a length of the storage tape  28  ( FIG. 1 ) wrapped about the hub  50  and contained between the flanges  52 ,  54 . The wrapping of successive layers of the storage tape  28  creates a compressive force on the hub  50  that can deform the hub  50  and the flanges  52 ,  54 . In addition, over the course of thousands of tape reel assembly  26 /drive chuck  106  engagements (i.e., chuck-ups), the driven teeth  56  will wear and create debris. To this end, and in one embodiment, at least the driven teeth  56  are formed of a stiff polymer including a lubricating additive.  
      An alternative embodiment of a tape reel assembly  120  in accordance with the present invention is illustrated in  FIGS. 5 and 6 .  FIG. 5  is a perspective view illustrating the tape reel assembly  120  as a two-piece assembly including a hub portion  122  and an upper flange  124 . With the embodiment of  FIG. 5 , the driven teeth  128  are formed as extensions of the hub  132 . The hub portion  122  includes an integrally formed lower flange  126 , the driven teeth  128 , and a hub  132 . In addition, the tape reel assembly  120  can include a metallic washer  130 . The lower flange  126  can be molded about the washer  130 , or the washer  130  can be separately assembled to the lower flange  126 .  
      A cross-sectional view of the hub portion  122  in accordance with the present invention is illustrated in  FIG. 6 . As shown, the hub portion  122  includes the hub  132  and the integrally formed lower flange  126 . The hub  132  includes a core  134  that defines an inner surface  136  and a tape-winding surface  138 , and the driven teeth  128 . The driven teeth  128  define an engagement surface  140 .  
      As described above, the wrapping of successive layers of the storage tape  28  ( FIG. 1 ) can create a compressive force on the hub portion  122  that can deform the hub  132  and the flanges  124 ,  126 . It is desired that the tape reel assembly  120  resist this deformation, and resist the wear associated with drive chuck  106  ( FIG. 4 ) engagements (i.e., chuck-ups). To this end, at least the driven teeth  128  are formed of a stiff polymer including a lubricating additive as previously described. With the embodiments of  FIGS. 5 and 6 , the hub portion  122  integrally forms the driven teeth  128 , with the hub portion  122  being molded from a polymer material including a lubricating additive. In a preferred embodiment, the hub portion  122 , and thus the driven teeth  128 , is formed from a polymer that includes a glass-filled polycarbonate and polytetrafluoroethylene as a lubricating additive added at up to 25% by weight. The lubricating additive can be any of the melt processable additives described above. Specifically, it has been advantageously discovered and described herein that driven teeth  128  formed from a polymer including 20% glass-filled polycarbonate and 5% polytetrafluoroethylene will resist wear associated with more than 10,000 engagements with the drive chuck  106  ( FIG. 4 ).  
     EXAMPLES AND COMPARATIVE EXAMPLE  
      The following examples further describe the tape reel assemblies of the present invention, methods of forming the tape reel assemblies, and the tests performed to determine their various characteristics. The examples are provided for exemplary purposes to facilitate an understanding of the invention, and should not be construed to limit the invention to the examples.  
      Tape reel assemblies were constructed as described below, and assembled into a set of data storage tape cartridges. Each of the cartridges were then repeatedly loaded into a series of side-loading tape drives from Seagate Removable Storage Solutions, now Certance of Costa Mesa, Calif. During loading, a drive chuck of the tape drive engaged, rotated, and disengaged a respective one of the tape reel assemblies. The series of steps including loading of the cartridge into the tape drive, the drive chuck engaging, rotating, and disengaging with the tape reel assembly, and unloading of the cartridge is designated as a “cycle.” A successful cycle is defined to be the completion of each of the steps listed above. An unsuccessful cycle is a cycle having a cartridge loading failure, or a cycle wherein a cartridge is rejected by the tape drive. When a cartridge tallies 10,000 successful cycles, the cartridge is said to “pass” the challenge. A “pass rate” represents the number of cartridges that pass the challenge in relation to the number of cartridges that were subjected to the challenge. For each Example and Comparative Example, the number of successful cycles was recorded, with the pass rate appearing in Table 1.  
     Example 1  
      Tape reel assemblies according to  FIG. 2  were constructed having driven teeth formed from a polymer including 20% glass-filled polycarbonate and 5% polytetrafluoroethylene (PTFE) added as a lubricating additive. Specifically, the polymer was compounded to include the 20% glass-filled polycarbonate and the 5% PTFE, where the PTFE was in the form of Teflon®. The polymer is identified as LNP DFL 4014 BK8-115, available from LNP, A GE Plastics Company, of Exton, PA. The tape reel assemblies of Example 1 were assembled into a set of 8 data storage tape cartridges. As shown in Table 1, the tape reel assemblies of Example 1 had a cartridge loading pass rate of 8 out of 8 and no cartridge loading failures. In this example, each of the cartridges containing the tape reel assemblies of Example 1 were successfully loaded into the tape drives for 10,000 cycles with zero loading failures before the experiment was terminated.  
     Example 2  
      Tape reel assemblies according to  FIG. 2  were constructed having driven teeth formed from a polymer including 10% glass-filled polycarbonate and 5% polytetrafluoroethylene (PTFE) added as a lubricating additive. Specifically, the polymer was compounded to include the 10% glass-filled polycarbonate and the 5% PTFE, where the PTFE was in the form of Teflon®. The polymer is identified as RTP 301 TFE 5, available from RTP Company, Winona, Minn. The tape reel assemblies of Example 2 were assembled into a set of 8 data storage tape cartridges. As shown in Table 1, the tape reel assemblies of Example 2 had a cartridge loading pass rate of 8 out of 8 with no cartridge loading failures. In this example, each of the cartridges were successfully loaded into the tape drives more than 11,800 cycles with zero cartridge loading failures before the experiment was terminated.  
     Example 3  
      Tape reel assemblies according to  FIG. 2  were constructed having driven teeth formed from a polymer including 10% glass-filled polycarbonate and 10% polytetrafluoroethylene (PTFE) added as a lubricating additive. Specifically, the polymer was compounded to include the 10% glass-filled polycarbonate and the 10% PTFE, where the PTFE was in the form of Teflon®. The polymer is identified as RTP 301 TFE 10, available from RTP Company, Winona, Minn. The tape reel assemblies of Example 3 were assembled into a set of 8 data storage tape cartridges. As shown in Table 1, the tape reel assemblies of Example 3 had a cartridge loading pass rate of 8 out of 8 with no cartridge loading failures. In this example, each of the cartridges were successfully loaded into the tape drives more than 11,000 cycles with zero cartridge loading failures before the experiment was terminated.  
     Example 4  
      Tape reel assemblies according to  FIG. 2  were constructed having driven teeth formed from a polymer including a 10% glass-filled polycarbonate and 15% polytetrafluoroethylene (PTFE) added as a lubricating additive. Specifically, the polymer was compounded to include the 10% glass-filled polycarbonate and the 15% PTFE, where the PTFE was in the form of Teflon®. The polymer is identified as RTP 301 TFE 15, available from RTP Company, Winona, Minn. The tape reel assemblies of Example 4 were assembled into a set of 7 data storage tape cartridges. As shown in Table 1, the tape reel assemblies of Example 4 had a cartridge loading pass rate of 7 out of 7 with no cartridge loading failures. In this example, each of the cartridges were successfully loaded into the tape drives more than 11,000 cycles with zero cartridge loading failures before the experiment was terminated.  
     Comparative Example 1  
      Tape reel assemblies according to  FIG. 2  were constructed having driven teeth composed of 20% glass-filled polycarbonate material. The material is identified as ML 5369-739, available from GE Plastics, Pittsfield, Mass. The tape reel assemblies of Comparative Example 1 were assembled into a set of 8 data storage tape cartridges and subjected to the testing described above. The sample cartridges utilizing the tape reel assemblies of Comparative Example 1 had a cartridge loading pass rate of 5 out of 8. Notably, cartridges containing the Comparative Example 1 tape reel assemblies exhibited approximately 7,200 loading cycles on average prior to cartridge loading failure.  
      As represented in Table 1 below, the inventive tape reel assemblies (described above), having driven teeth formed from a polymer including PTFE as a lubricating additive, each exceeded the 10,000 cycle cartridge loading challenge with zero cartridge loading failures.  
                           TABLE 1                       Driven teeth   10,000 Cycle       Average       Composition of Tape   Cartridge   Cartridge   Number of       Reel Assembly,   Loading Pass   Loading   Insertions before       Example   Rate   Failures   Loading Failure                  20% glass-filled   8 of 8   None   N/A       polycarbonate, 5%       polytetrafluoroethylene       (PTFE), Example 1       10% glass-filled   8 of 8   None   N/A       polycarbonate, 5%       PTFE, Example 2       10% glass-filled   8 of 8   None   N/A       polycarbonate, 10%       PTFE, Example 3       10% glass-filled   7 of 7   None   N/A       polycarbonate, 15%       PTFE, Example 4       Conventional glass-   5 of 8   3 of 8   7117       filled polycarbonate,       Comparative Example 1                  
 
      Although specific embodiments have been illustrated and described herein for purposes of description of the preferred embodiment, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. Those with skill in the chemical, mechanical, electromechanical, electrical, and computer arts will appreciate that the present invention can be implemented in a wide variety of embodiments. Specifically, a number of other tape reel assembly constructions other than those shown are within the scope of this invention. In particular, this application is intended to cover any adaptations or variations of tape reel assemblies having driven teeth formed from a polymer including a lubricating additive. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.