Abstract:
A disc drive system includes a base or deck, a disc stack rotatably attached to the base, and an actuator assembly movably attached to the base. The disc stack includes a spindle, a hub attached to the spindle and discs attached to the hub. The spindle is attached to the base or deck using a fastener that passes into a threaded opening in the spindle. The spindle also includes several electrical contact pads. The base or deck has openings positioned near the electrical contact pads as well as an opening through which the fastener passes to mount the spindle to the base or deck. A printed circuit board is connected to the bottom of the base or deck. A connector is used to attach the electrical contact pads on the spindle to the electronics on the printed circuit board. The connector includes several contact elements. The contact elements extending through openings in the deck and contact a corresponding electrical contact pad on the spindle. The connector includes a ring of material that attaches to the printed circuit board to provide a strain relieved connection. The connector also supports the electrical contacts and is made of an insulative material. The electrical contacts have a spring end which is cantilevered off the ring. The spring end extends from the ring providing a preloaded contact through openings in the base or deck and to the electrical contact pads on the printed circuit. The other end is soldered directly to the printed circuit board.

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application Serial No. 60/085,791, filed May 18, 1998 under 35 USC119(e). 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the field of mass storage devices. More particularly, this invention relates to a disc drive which includes a spindle motor having electrical contacts between a printed circuit board and the spindle. 
     BACKGROUND OF THE INVENTION 
     One of the key components of any computer system is a place to store data Computer systems have many different places where data can be stored. One common place for storing massive amounts of data in a computer system is on a disc drive. The most basic parts of a disc drive are a disc that is rotated, an actuator that moves a recording/playback transducer to various locations over the disc, and electrical circuitry that is used to write and read data to and from the disc. The disc drive also includes circuitry for encoding data so that it can be successfully retrieved and written to the disc surface. A microprocessor controls most of the operations of the disc drive as well as passing the data back to the requesting computer and taking data from a requesting computer for storing to the disc. 
     The transducer is typically housed within a small ceramic block. The small ceramic block is passed over the disc in a transducing relationship with the disc. The transducer can be used to read information representing data from the disc or write information representing data to the disc. When the disc is operating, the disc is usually spinning at relatively high revolutions per minute (“RPM”). 
     These days common rotational speeds are 7200 RPM. Some rotational speeds are as high as 10,000 RPM. Higher rotational speeds are contemplated for the future. These high rotational speeds place the small ceramic block in high air speeds. The small ceramic block, also referred to as a slider, is usually aerodynamically designed so that it flies over the disc. The best performance of the disc drive results when the ceramic block is flown as closely to the surface of the disc as possible. Today&#39;s small ceramic block or slider is designed to fly on a very thin layer of gas or air. In operation, the distance between the small ceramic block and the disc is very small. Currently, “fly” heights are only a few micro inches. 
     Information representative of data is stored on the surface of the memory disc. Disc drive systems read and write information stored on tracks on memory discs. Transducers, in the form of read/write heads, located on both sides of the memory disc, read and write information on the memory discs when the designated transducer is accurately positioned over the designated track on the surface of the memory disc. The transducer is also said to be moved to a target track. As the memory disc spins and the read/write head is accurately positioned above a target track, the read/write head can store data onto a track by writing information representative of data onto the memory disc. Similarly, reading data on a memory disc is accomplished by positioning the read/write head above a target track and reading the stored material on the memory disc. To write on or read from different tracks, the read/write head is moved radially across the tracks to a selected target track. The data is divided or grouped together on the tracks. In some disc drives, the tracks are a multiplicity of concentric circular tracks. In other disc drives, a continuous spiral is one track on one side of a disc drive. Servo feedback information is used to accurately locate the transducer. The actuator assembly is moved to the required position and held very accurately during a read or write operation using the servo information. It should be noted that the tracks on a disc drive are very thin and closely spaced. Currently, track densities are greater than 10,000 tracks per inch. In practical terms, this means that there are as many as 12 tracks across the width of a single human hair. Of course, track densities will increase in the future. 
     In the past, the spindle or hub was mounted to the base or deck of the disc drive. The spindle included electrical contacts which formed electrical connections to the windings of the motor and possibly the center tap of the motor. The motor is commutated to spin the spindle and the attached hub. One or more discs are attached to the hub. A flex cable was used to connect the electrical contact pads on the spindle to the printed circuit board external to the disc enclosure. In some instances the deck included a special throughway that provided a sealed connection to the printed circuit board. The flex cable is long, and cumbersome in terms of manufacture. In addition, connector and seal through the base or deck of the disc drive is another special part which adds inventory during manufacture and which makes assembly more complex. 
     Some disc drives have replaced the spindle motor pads with pins that can be accessed with another connector that directly connects to the printed circuit board on the outside of the disc enclosure. In the past, these have been difficult to align and many times, during manufacture, the pins associated with the spindle or the connector to which the pins attach may become damaged. Both may also become damaged. In addition, the solder joints were the only means for holding the connector to the printed circuit board. In the presence of shock loading to the connector, the solder joints may break free and the disc drive would fail. There is also need for non-standard hardware that would cost more than a standard screw type fastener. A spanner type or flat nut is needed to hold the spindle of the in-hub motor in place. This special part costs much more than a standard connector. In addition, the spanner nut also tended to gall the deck as it was tightened. Galling caused the torque necessary to tighten the part to read high. When robots are used to attach the spindle to the base or deck of the disc drive, the robots tighten to a specified torque. With galling, the torque may be reached before the spindle is truly tightened. 
     To lessen the problems associated with previous spindle motor to printed circuit board connectors, there is a need for a connector which can directly connect the spindle motor to the printed circuit board. There is also a need for a connector which does not require accurate alignment. In other words, the connector should be more forgiving so that it can tolerate slight misalignments without damaging the printed circuit board or the electrical connectors of the spindle motor. What is also needed is a connector that resists breaking solder joint connections when the connector undergoes a shock loading event. Also needed is a reliable electrical connection so that the disc drive is also reliable. 
     SUMMARY OF THE INVENTION 
     A disc drive system includes a base or deck, a disc stack rotatably attached to the base, and an actuator assembly movably attached to the base. The disc stack includes a spindle, a hub attached to the spindle and discs attached to the hub. The spindle is attached to the base or deck using a fastener that passes into a threaded opening in the spindle. The spindle also includes several electrical contact pads The base or deck has openings positioned near the electrical contact pads as well as an opening through which the fastener passes to mount the spindle to the base or deck. A printed circuit board is connected to the bottom of the base or deck. A connector is used to attach the electrical contact pads on the spindle to the electronics on the printed circuit board. The connector includes several contact elements. The contact elements extending through openings in the deck and contact a corresponding electrical contact pad on the spindle. The connector includes a ring of material that attaches to the printed circuit board to provide a strain relieved connection. The connector also supports the electrical contacts and is made of an insulative material. The electrical contacts have a spring end which is cantilevered off the ring. The spring end extends from the ring, through openings in the base or deck and to the electrical contact pads on the spindle motor. The other end is soldered directly to the printed circuit board. 
     Advantageously, the connection between spindle motor and the printed circuit board is made directly. The connector which does not require accurate alignment and can tolerate slight misalignments without damaging the printed circuit board or the electrical connectors of the spindle motor. The connector also includes tabs that serve as strain relievers so that solder joints do not tend to break when the connector undergoes a shock loading event. The connector also provides a reliable electrical connection so that the disc drive is also more reliable. The invention also eliminates the need for a special non-standard spanner nut so that less expensive fasteners can be used. The spindle shaft no longer needs special outside threads. The standard fasteners use a standard thread inside the shaft and do not have problems with galling and therefore can be more reliably torqued using robotics during assembly. The effective shaft length is increased which allows increased bearing span which in turn reduces problems resulting from spindle tilt. The electrical connector is eliminated from within the shaft which simplifies construction of the spindle shaft. In addition, the shaft no longer needs a wide flange which saves material and machining time when compared to other methods. This also reduces spindle cost. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of a disc drive with a multiple disc stack and a ramp assembly for loading and unloading transducers to and from the surfaces of the discs. 
     FIG. 2 is a partially exploded broken away view of a base, a printed circuit board, and a spindle of the present invention. 
     FIG. 3 is a bottom view of a printed circuit board. 
     FIG. 4 is a bottom view of the base or deck of the disc drive. 
     FIG. 5 is a perspective view of the connector. 
     FIG. 6 is a cross section view of the connector attached to the spindle and to the electrical contact pads on the spindle of the disc drive. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. 
     The invention described in this application is useful with all mechanical configurations of disc drives having either rotary or linear actuation. In addition, the invention is also useful in all types of disc drives including hard disc drives, zip drives, floppy disc drives and any other type of drives where unloading the transducer from a surface and parking the transducer may be desirable. FIG. 1 is an exploded view of one type of a disc drive  100  having a rotary actuator. The disc drive  100  includes a housing  112 , and a housing cover  114 . The housing or base  112  and housing cover  114  form a disc enclosure. Rotatably attached to the housing  112  on an actuator shaft  118  is an actuator assembly  120 . The actuator assembly  120  includes a comb-like structure  122  having a plurality of arms  123 . Attached to the separate arms  123  on the comb  122 , are load beams or load springs  124 . Load beams or load springs are also referred to as suspensions. Attached at the end of each load spring  124  is a slider  126  which carries a magnetic transducer  150 . The slider  126  with the transducer  150  form what is many times called the head. It should be noted that one actuator assembly has many transducers  150  and that is what is shown in the figures. It should also be noted that this invention is equally applicable to sliders having more than one transducer, such as what is referred to as an MR or magneto resistive head in which one transducer  150  is generally used for reading and another is generally used for writing. On the end of the actuator arm assembly  120  opposite the load springs  124  and the sliders  126  is a voice coil  128 . 
     Attached to the housing  112  is one of a pair of magnets  130  and  130 ′. 
     The other of the pair of magnets  130 ′ is attached to the housing cover  114 . The pair of magnets  130  and  130 ′, and the voice coil  128  are key parts of a voice coil motor which applies a force to the actuator assembly  120  to rotate it about the actuator shaft  118 . Also mounted to the housing  112  are a spindle motor and spindle hub  30   133 . The spindle motor is an “in-hub” motor which means the motor fits within the spindle hub  133 . The spindle motor rotates the spindle hub. In FIG. 1, a number of discs  134  are attached to the spindle hub  133 . In other disc drives a single disc or a different number of discs may be attached to the hub. The invention described herein is equally applicable to all other such disc drives. 
     The invention deals with the electrical connection between the electrical pads of a spindle motor (shown in FIG. 6) and the electrical pads of the printed circuit board. FIG. 2 is a partially exploded broken away view of the base  112  (also called the deck), a printed circuit board  300 , a spindle  200 , and a connector  500  according to the present invention. 
     The base  112  includes a well  210 . The well is sized to receive the spindle  200 . At the bottom of the well  210  is an opening  212  for receiving a fastener  220 . Positioned around the opening  212  are openings  213 ,  214  and  215 . The spindle includes a fixed shaft  202  as well as a hub  204  which rotates about the fixed shaft  202 . The hub  204  includes a flange  205  for carrying discs. An in-hub spindle motor (shown in FIG. 6) is used to rotate the hub  204  with respect to the fixed shaft  202 . The in-hub motor includes windings which are commutated in order to turn the hub  204 . Electrical energy or power is input to the windings via a set of pads  206 ,  207  and  208  positioned on one end of the fixed shaft  202 . The fixed shaft also includes a threaded opening  209  which is located substantially along the axis of the fixed shaft  202  of the spindle  200 . The spindle  200  is positioned within the well  2100  so that the electrical pads  206 ,  207  and  208  are positioned over the openings  213 ,  214  and  215  in the deck  112 . A fastener  220  is then passed through the opening  212  in the base or deck  112  and threaded into the threaded opening  209  of the fixed shaft  202  of the spindle  200 . The end result is that the spindle  200  is mounted to the deck or base  112  with the pads  206 ,  207  and  208  accessible through openings  213 ,  214  and  215  in the base or deck  112  of the disc drive  100 . 
     Also shown in FIG. 2 is the printed circuit board  300 . The printed circuit board includes electronics necessary to read and write data to the discs of the disc drive as well as motor controller electronics  310  which is used to control the speed at which the in-hub spindle motor (shown in FIG. 6) is commutated. The motor controller electronics  310  includes inputs and outputs which are used to deliver power to the windings of the in-hub motor as well as to receive control signals back from the in-hub motor. The printed circuit board  300  includes an opening  320 . The opening is positioned so that when the printed circuit board is attached to the base  112  of the disc drive, the opening  320  will be large enough and in position so that the openings  213 ,  214  and  215  may be accessed through the opening  320 . Positioned around the opening  320  are a set of pads  313 ,  314  and  315 . The pad  313 ,  314  and  315  are connected to the motor controller electronics  310 . The pads  313 ,  314  and  315  are positioned around the periphery of the opening  320 . A connector  500  provides for direct attachment between the pads  313 ,  314  and  315  of the circuit board  300  to the pads  206 ,  207  and  208  on the fixed shaft  202  on the spindle  200 . The connector  500  includes three contact elements  513 ,  514  and  515 . Each of the contact elements has an up turned end which extends through the openings  213 ,  214  and  215  in the base and contacts a corresponding pad  206 ,  207  or  208  on the fixed shaft  202  of the spindle  200 . The other ends of the contact elements  513 ,  514  and  515  are electrically connected to the pads  313 ,  314  and  315 , respectively. 
     FIG. 3 is a top view of the printed circuit board  300  with the connector  500  attached there too. The connector includes the contact elements  513 ,  514  and  515 . The ends of the contact elements are electrically connected to pads  313 ,  314  and  315 . The contact elements  513 ,  514  and  515  are supported by a Y-shaped cap  520 . The printed circuit board  300  also includes a first slot  333 , a second slot  334  and a third slot  335 . The slots  333 ,  334  and  335  extend through the printed circuit board and form part of a strain relief mechanism. The printed circuit board also includes openings  343 ,  344  and  345 . Openings  343 ,  344  and  345  are alignment openings which are used to align the connector  500  when it is attached to the printed circuit board  300 . 
     FIG. 4 is a bottom view of the base  112  or deck of the disc drive  100 . The opening  212  includes a bevel or countersunk portion so that a corresponding fastener  220  includes a portion which engages the bevel. The openings  213 ,  214  and  215  are positioned around the opening  212 . The openings  213 ,  214 , and  215  can be round as shown in FIG. 2 or can be more of a rounded slot as shown in FIG.  4 . 
     FIG. 5 is a perspective view of the connector  500 . The connector  500  includes a ring  510  and a cap  520 . As shown in FIG. 5 the cap  520  is a y-shaped element. The cap  520  could also be solid and totally cover the inner portion of the ring  510 . The ring  510  includes a beveled wall  511 . The beveled wall includes a series of channels which extend through the ring  510  and into the cap  520 . The channels  533 ,  534  and  535  are dimensioned to receive the contact elements  513 ,  514  and  515 . The channels  533 ,  534  and  535  hold the electrical contacts  513 ,  514  and  515 , respectively. Each of the contact elements  513 ,  514  and  515  includes a cantilevered end  540  and a solderable end  542 . The cantilevered end is curved so that when the electrical contact contacts one of the electrical pads  206 ,  207  or  208  of the spindle, the curved cantilevered end will scrub across the pad and produce a good, reliable preloaded electrical contact. The free end  542  of the electrical contact is solderable and is positioned over one of the pads  313 ,  314  and  315  on the printed circuit board  300 . The ring  510  includes at least two alignment knobs  550  and  552 . The alignment knobs  550  and  552  fit within the alignment openings  343 ,  344  or  345  in the printed circuit board. The alignment knobs  552  and  550  are dimensioned so that they fit within any of the alignment openings  343 ,  344  and  345  of the printed circuit board  300 . When the alignment knobs fit into any two of the three alignment openings  343 ,  344  or  345  the ring is aligned such that the solderable ends  542  of each of the contact elements  513 ,  514  and  515  are positioned over the pads  313 ,  314  and  315  on the printed circuit board which are in turn connected to the motor controller electronics module  310  by electrical pathways within the printed circuit board  300 . Also attached to the ring  510  is a first flexible pawl  563 , a second flexible pawl  564  and a third flexible pawl  565 . The pawls  563 ,  564  and  565  have a flexible body and a hook end so that the flexible pawl  563 ,  564  and  565  may be inserted into any of the slots  333 ,  334  and  335  in the printed circuit board to produce a snap fit. The flexible body of the pawls  563 ,  564  and  565  flexes while the hook end engages the slots  333 ,  334  and  335 . When finally inserted the flexible bodies  563 ,  564  and  565  snap back and allow the hook ends to latch into the open slots  333 ,  334  and  335  of the printed circuit board. The flexible pawls and their snap fit within the openings provide a strain relief mechanism which keeps the solderable ends  542  of the contact elements  513 ,  514  and  515  attached to the corresponding pads  313 ,  314  and  315  on the printed circuit board and preloaded in the event of a shock loading or bumping during manufacturer. 
     FIG. 6 is a cross sectional view of a portion of the spindle attached to the base  112  and the printed circuit board  300 . The fixed shaft  202  had an end with an electrical pad  206  thereon. The electrical pad  206  is connected to a motor winding  610  via a wire  611  that connects the pad  206  to the motor winding  610 . The contact element with the cantilevered end  540  contacting the pad makes electrical contact between the pad  206  and the pad  313  on the printed circuit board  300 . The printed circuit board  300  is attached to the bottom of the base  112  of the disc drive  100 . Motor controller electronics  310  (shown in FIG. 3) controls the amount of electricity and the timing of the pulse that is sent to the windings to properly commutate the in-hub motor. An in-hub motor  600  is formed from the winding  610  and a magnet  620  is positioned inside the hub  204 . The magnet  620  and the coils  610  form the in-hub motor. As can be seen, when assembled the contact element  513  extends into opening  213  in the base  112  of the disc drive  100 . A first bearing  630  and a second bearing  632  allow the hub  204  to rotate about the fixed shaft  202  of the spindle  200 . The opening  209  receives a standard screw. The standard screw can be used in lieu of any specialized fasteners for connecting the spindle to the base  112 . 
     Advantageously, the connection between spindle motor and the printed circuit board is made directly. The connector which does not require accurate alignment and can tolerate slight misalignments without damaging the printed circuit board or the electrical connectors of the spindle motor. The connector also includes tabs that serve as strain relievers so that solder joints do not tend to break when the connector undergoes a shock loading event. The connector also provides a reliable electrical preloaded connection so that the disc drive is also more reliable. The invention also eliminates the need for a special non-standard spanner nut so that less expensive fasteners can be used. The spindle shaft no longer needs special outside threads. The standard fasteners use a standard thread inside the shaft and do not have problems with galling and therefore can be more reliably torqued using robotics during assembly. The effective shaft length is increased to increase the bearing span which in turn reduces problems resulting from spindle tilt. The electrical connector is eliminated from within the shaft which simplifies construction of the spindle shaft. In addition, the shaft no longer needs a wide flange which saves material and machining time when compared to other methods. This also reduces spindle cost. 
     Conclusion 
     As mentioned previously, a magnetic disc drive  100  includes a spindle  200  which in turn includes a first electrical contact pad  206  and a second electrical contact pad  207 . The spindle  200  also has a threaded opening  209  therein. The disc drive  100  includes a deck  112  having a first opening  213  therein positioned near the first electrical contact pad  206  and a second opening  214  therein positioned near the second electrical contact pad  207 . The deck  112  also has a third opening  212  therein positioned near the threaded opening  209 . The threaded opening  209  receives a fastener to attach the spindle  200  to the deck  112 . A printed circuit board  300  is connected to the deck  112  on a side opposite the spindle  200 . A connector  500  is attached to the printed circuit board for making electrical connection between the first electrical pad  206  and the printed circuit board  300 . The connection  500  also makes electrical connection between the second electrical pad and the printed circuit board. 
     Also disclosed is a magnetic disc drive  100  which includes a spindle  200  which in turn includes a first electrical contact pad  206  and a second electrical contact pad  207 . The spindle  200  also has a threaded opening  209  therein. The disc drive  100  includes a deck  112  having a first opening  213  therein positioned near the first electrical contact pad  206  and a second opening  214  therein positioned near the second electrical contact pad  207 . The deck  112  also has a third opening  212  therein positioned near the threaded opening  209 . The threaded opening  209  receives a fastener to attach the spindle  200  to the deck  112 . A printed circuit board  300  is connected to the deck  112  on a side opposite the spindle  200 . A connector  500  is attached to the printed circuit board  300  and includes a first contact element  513  and a second contact element  514 . The first contact element  513  extends through the first opening  213  in the deck  112  and contacts the first electrical contact pad  206 . The second contact element  514  extends through the second opening  214  in the deck  112  and contacting the second electrical contact pad  207 . The connector  500  further includes a latching mechanism for attaching the connector  500  to the printed circuit board  300 . The magnetic disc drive of claim  3  wherein the latching mechanism includes a flexible pawl  563 ,  564 ,  565  having a hook end. The printed circuit board  300  includes an opening  333 ,  334 , and  335  therein for receiving the flexible pawl  563 ,  564 ,  565 . The pawl  563 ,  564 ,  565  is adapted to snap fit into the opening  333 ,  334 , and  335  in the printed circuit board  300 . The connector  500  further comprises a mechanism for aligning the connector  500  so the first contact element  513  aligns to the first electrical contact pad  206  on the spindle  200  and the second contact element  514  aligns to the second contact pad  207  on the spindle  200 . The first contact element  513  and the second contact element  514  each include a cantilevered spring portion  540 . The first contact element  513  and the second contact element  514  each have an end with a cantilevered spring portion  540  for contacting and preloading a pad  206 ,  207 ,  208  on the spindle  200 . The first contact element  513  and the second contact element  514  each have another end  542  for contacting a pad  313 ,  314 ,  315  on the printed circuit board  300 . 
     Also disclosed is a connector  500  for electrically connecting the coils of a spindle  200  motor to a printed circuit board  300  of a disc drive  100 . The spindle motor has a first electrical pad  206  and a second electrical pad  207 . The connector  500  further includes a ring  510 . The ring  510  includes a first contact element  513  having a first cantilevered end  540  and a first solderable end  542 . The first contact element  513  is attached to the ring  510 . The ring  510  includes a second contact element  514  having a second cantilevered end  540  and a second solderable end  542 . The second contact element  514  is also attached to the ring  510 . At least two alignment knobs  550 ,  552  are attached to the ring  510 . The alignment knobs  550 ,  552  are for aligning the ring  510  in an orientation so that the first contact element  513  aligns to one of the first electrical pad  206  and the second electrical pad  207 , and so that the second contact element  514  aligns to the other of the first electrical pad  206  and the second electrical pad  207 . The connector  500  further includes a strain relief mechanism adapted to latch to the printed circuit board  300 . The strain relief mechanism includes a plurality of snap fit fingers  563 ,  564 ,  565  attached to the ring  510 . The strain relief mechanism can also be said to include a plurality flexible pawls  563 ,  564 ,  565 . Each of the flexible pawls  563 ,  564 ,  565  has a hook end. The connector  500  also includes a structure  520  attached to the ring  510  to support the first contact element  513  and the second contact element  514  at positions within the ring  510 . The structure  520  may be a cap. The structure  520  is made of an electrically insulative material. The first contact element  513  and the second contact element  514  are made of electrically conductive material. The first contact element  513  is formed as a spring  510 . The second contact element  514  is also formed as a spring  510 . 
     Also disclosed is a printed circuit board  300  for making electrical connection to a set of electrical pads  206 ,  207 ,  208  of the spindle  200  of a disc drive  100 . The printed circuit board  300  includes a motor controller electronic package  310  associated with the printed circuit board  300  and a plurality of contact pads  313 ,  314 ,  315  for making electrical connection to the motor controller electronics package  310 . The printed circuit board  300  has a spindle access opening  320  therein. The contact pads  313 ,  314 ,  315  of the printed circuit board  300  are positioned near the spindle access opening  320  in the printed circuit board  300 . An electrical contact  513 ,  514 ,  515  has a first end  542  and a second end  540 . The first end  542  electrically attached to one of the plurality of contact pads  313 ,  314 ,  315  of the printed circuit board  300 . The second end  540  is positioned to contact one of the pads associated with the spindle  206 ,  207 ,  208 . The printed circuit board  300  further includes a ring  510  element attached to the printed circuit board  300  for supporting a portion of the electrical contact  513 ,  514 ,  515 . The printed circuit board  300  has openings  333 ,  334 ,  335  about the periphery of the spindle access opening  320 . The ring  510  element has at least two flexible fingers  563 ,  564 , which extend into the openings  333 ,  334 ,  335  about the periphery of the spindle access opening  320 . 
     It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.