Patent Publication Number: US-10760340-B2

Title: Up drill apparatus and method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of and claims priority to U.S. patent application Ser. No. 14/863,760, filed on Sep. 24, 2015, which claims priority to U.S. Provisional Patent Application No. 62/065,182, filed on Oct. 17, 2014, each of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     In one aspect, one disclosed embodiment relates to an apparatus having two tapered circumferential areas rotating against each other with at least one rolling element placed between the tapered circumferential areas. 
     In another aspect, a downhole tool embodiment is disclosed. More particularly, but not by way of limitation, this embodiment relates to a downhole tool used in drilling wellbores. The downhole tool may be used with a drilling motor and bit, and wherein the wellbore may include a straight hole, deviated hole, or horizontal hole. 
     SUMMARY OF THE INVENTION 
     In one embodiment, an apparatus is disclosed that includes a rotating segment having a first radial surface with a first circumferential profile; a non-rotating segment having a second radial surface with a second circumferential profile; a housing disposed around the first and second radial surfaces; and one or more rolling elements disposed between and in contact with the first and second radial surfaces for transferring the non-rotating segment in an axial direction upon rotation of the rotating segment. Each rolling element moves 360 degrees along a circular path relative to the first radial surface and 360 degrees along a circular path relative to the second radial surface. The rotating segment rotates more than 360 degrees relative to the non-rotating segment. The first circumferential profile may include the tapered section, which may include an undulating waveform profile. The second circumferential profile may include the tapered section, which may include an undulating waveform profile. Each of the rolling elements may include a spherical outer surface. In one embodiment, the apparatus may include two rolling elements in contact with one another, and with each rolling element having a diameter that is equal to one-half of an inner diameter of the housing. In another embodiment, the apparatus may include three or more rolling elements, with each rolling element in contact with two adjacent rolling elements. In yet another embodiment, the apparatus may include two or more rolling elements and a guide member, which is disposed between the first and second radial surfaces for retaining the rolling elements in a fixed position relative to one another. 
     In another embodiment, an apparatus is disclosed that includes a first rotating segment having a first radial surface with a first circumferential profile; a second rotating segment having a second radial surface with a second circumferential profile; a housing disposed around the first and second radial surfaces; and one or more rolling elements disposed between and in contact with the first and second radial surfaces for transferring the second rotating segment in an axial direction upon rotation of the first rotating segment. The second rotating segment rotates at different rotational rate than the first rotating segment. Alternatively, first and second rotating segments rotate in opposite directions. Each rolling element moves 360 degrees along a circular path relative to the first radial surface and 360 degrees along a circular path relative to the second radial surface. The first rotating segment rotates more than 360 degrees relative to the second rotating segment. The first circumferential profile may include the tapered section, which may include an undulating waveform profile. The second circumferential profile may include the tapered section, which may include an undulating waveform profile. Each of the rolling elements may include a spherical outer surface. In one embodiment, the apparatus may include two rolling elements in contact with one another, and with each rolling element having a diameter that is equal to one-half of an inner diameter of the housing. In another embodiment, the apparatus may include three or more rolling elements, with each rolling element in contact with two adjacent rolling elements. In yet another embodiment, the apparatus may include two or more rolling elements and a guide member, which is disposed between the first and second radial surfaces for retaining the rolling elements in a fixed position relative to one another. 
     In another embodiment, a downhole apparatus connected to a workstring within a wellbore is disclosed. The downhole apparatus includes a power mandrel having a first end operatively connected to a power section member and a second end having a rotating cam surface, with the power mandrel being disposed within an outer housing. The downhole apparatus also includes an anvil sub operatively attached to the workstring, with the anvil sub having a stationary cam surface operatively configured to engage the rotating cam surface. As the rotating cam surface engages the stationary cam surface, the anvil sub and the workstring are moved axially within the wellbore. The downhole apparatus may also include a first spline member configured on an outer surface of the anvil sub and a second spline member configured on the inner surface of the outer housing, with the first and second spline members cooperating to allow relative axial movement between the anvil sub and the outer housing. The power mandrel may be partially disposed within the outer housing. The apparatus may also include a biasing member operatively disposed about the anvil sub, with the biasing member having a first end engaging a shoulder on the anvil sub and a second end engaging a shoulder on the outer housing for biasing the anvil sub away from the shoulder of the outer housing. The downhole apparatus may include a radial bearing positioned on the inner surface of the outer housing and operatively configured to engage the power mandrel, and a thrust bearing configured to engage a shoulder on the power mandrel and a shoulder on the inner surface of the outer housing. In one embodiment, the rotating cam surface includes a radial face having an inclined portion and an upstanding portion and the stationary cam surface includes a radial face having a reciprocal inclined portion and a reciprocal upstanding portion. In another embodiment, the rotating and stationary cam surfaces may each include an undulating radial face. In still another embodiment, the rotating and stationary cam surfaces may each include a tapered circumferential profile. In yet another embodiment, the rotating and stationary cam surfaces may each include an undulating, multiple segmented radial face. The downhole apparatus may include one or more rolling elements disposed between and in contact with the rotating cam surface and the stationary cam surface. The rolling element may include a spherical outer surface. In one embodiment, the downhole apparatus includes two rolling elements in contact with one another, each having a diameter that is equal to one-half of an inner diameter of the housing. In another embodiment, the downhole apparatus includes three or more rolling elements, with each of the rolling elements in contact with two adjacent rolling elements. In a further embodiment, the downhole apparatus includes two or more rolling elements and a guide member disposed between the rotating cam surface and the stationary cam surface for retaining the rolling elements in a fixed position relative to one another. The power section member may include a rotor-stator unit. The rotor-stator unit may be part of a downhole motor. 
     Also disclosed is a method of drilling a wellbore with a downhole apparatus. The downhole apparatus is connected to a workstring within the wellbore, and the apparatus includes: a power mandrel having a first end operatively connected to a power section member and a second end having a rotating cam surface; an anvil sub operatively attached to the workstring, with the anvil sub having a stationary cam surface operatively configured to engage with the rotating cam surface. The method may include providing the apparatus on the workstring, lowering the downhole apparatus and the workstring into the wellbore, pumping fluid into the workstring, rotating the power mandrel while maintaining the anvil sub in a stationary position, and engaging the stationary cam surface with the rotating cam surface so that the anvil sub and the workstring are moved axially within the wellbore relative to the power mandrel. The rotating cam surface may include a radial face having an inclined portion and an upstanding portion, and the stationary cam surface may include a radial face having a reciprocal inclined portion and a reciprocal upstanding portion. In one embodiment, the rotating and stationary cam surfaces may each include an undulating radial face. In another embodiment, the rotating and stationary cam surfaces may each include a tapered circumferential area. The downhole apparatus may further include one or more rolling elements disposed between and in contact with the stationary cam surface and the rotating cam surface. 
     In yet another embodiment, an apparatus connected to a workstring within a wellbore. The apparatus includes: an outer housing; a power mandrel having a first end operatively connected to a power section member and a second end having a rotating cam surface, with the power mandrel being disposed within the outer housing; a rotating element engaging the rotating cam surface; an anvil sub operatively attached to the workstring, with the anvil sub having a stationary cam surface operatively configured to engage with the rotating element. As the rotating cam surface rotates and engages the rotating element, the anvil sub and the workstring are moved axially within the wellbore. The apparatus may also include a first spline member configured on an outer surface of the anvil sub and a second spline member configure on the inner surface of the outer housing, with the first and second spline members cooperating to allow relative axial movement between the anvil sub and the outer housing. The apparatus may further include: a spring operatively disposed about the anvil sub, with the spring having a first end engaging a shoulder on the anvil sub and a second end engaging a shoulder on the outer housing, wherein the spring biases the anvil sub and the outer housing in opposite axial directions. The apparatus may also include a radial bearing positioned on the inner surface of the outer housing and operatively configured to engage the power mandrel, and a thrust bearing configured to engage a shoulder on the power mandrel and a shoulder on the inner surface of the outer housing. The rotating cam surface may include a radial face having an inclined portion and an upstanding portion and the stationary cam surface may include a radial face having a reciprocal inclined portion and a reciprocal upstanding portion. In one embodiment, the rotating and stationary cam surfaces may each include an undulating radial face. In another embodiment, the rotating and stationary cams may each include a tapered circumferential. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial cross-sectional view of a one embodiment of the up-drill apparatus of the present disclosure. 
         FIG. 2  is a partial cross-sectional view of another embodiment of the up-drill apparatus of the present disclosure. 
         FIG. 3A  is a view of a first embodiment of the cam surface of the present disclosure. 
         FIG. 3B  is a view of the cam surface profile seen in  FIG. 3A . 
         FIG. 3C  is a view of a second embodiment of the cam surface of the present disclosure. 
         FIG. 3D  is a view of a third embodiment of the cam surface of the present disclosure. 
         FIG. 4  is a view of one embodiment of reciprocal of cams 
         FIG. 5  is a partial cross-sectional view of another embodiment of the up-drill apparatus of the present disclosure. 
         FIG. 6  is a perspective view of the rolling elements shown in  FIG. 5  disposed within a guide member. 
         FIG. 7A  is a partial cross-sectional view of another embodiment of the up-drill apparatus of the present disclosure. 
         FIG. 7B  is a partial cross-sectional view of the embodiment of the up-drill apparatus of the present disclosure shown in  FIG. 7A  with a guide member. 
         FIG. 8  is a perspective view of the rolling elements shown in  FIG. 7B  disposed within a guide member. 
         FIG. 9  is a schematic illustration of the up drill apparatus disposed within a wellbore. 
         FIG. 10  is a cross-sectional view of an apparatus for applying axial movement with a rotating member. 
         FIG. 11A  is a cross-sectional view of the apparatus taken along line A-A in  FIG. 10 . 
         FIG. 11B  is an alternate cross-sectional view of the apparatus taken along line A-A in  FIG. 10 . 
         FIG. 11C  is another alternate cross-sectional view of the apparatus taken along line A-A in  FIG. 10 . 
         FIG. 11D  is yet another alternate cross-sectional view of the apparatus taken along line A-A in  FIG. 10 . 
         FIG. 12  is a cross-sectional view of the apparatus of  FIG. 10  including a guide member. 
         FIG. 13A  is a cross-sectional view of the apparatus taken along line B-B in  FIG. 12 . 
         FIG. 13B  is an alternate cross-sectional view of the apparatus taken along line B-B in  FIG. 12 . 
         FIG. 13C  is another alternate cross-sectional view of the apparatus taken along line B-B in  FIG. 12 . 
         FIG. 13D  is yet another alternate cross-sectional view of the apparatus taken along line B-B in  FIG. 12 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to  FIG. 1 , a partial cross-sectional view of one embodiment of the up-drill apparatus  2  of the present disclosure will now be described. The apparatus  2  includes an outer housing, wherein the outer housing may include a first housing  4  that is threadedly connected to a second housing  6 , wherein the first housing  4  has an inner portion  8  that extends to the outer portion  10  and the second housing  6  has an inner portion  12  that extends to the outer portion  14 . The housings  4  and  6  will have disposed therein an upper power mandrel, seen generally at  16 , which extends to a power section member, such as rotor-stator unit  18 . The rotor-stator unit  18  may be part of a downhole motor means for drilling a well. Downhole motors are well known in the art and are commercially available from Ashmin, LC. Alternatively, apparatus  2  may be a stand-alone unit with a rotor-stator unit  18  separate from any downhole motor. As seen in  FIG. 1 , the upper power mandrel  16  includes an inner bore  20  that extends to a spline member  22 , wherein the spline member  22  is configured to engage an intermediate power mandrel  24 . 
     The outer surface of upper power mandrel  16  contains indentations  26 ,  28  for placement of axial thrust bearings  30 ,  32 , respectively, for absorbing axial thrust loads during rotational operations as well understood by those of ordinary skill in the art. The upper power mandrel  16  also contains rotating cam surface, seen generally at  34 , which will be described later in the disclosure. The intermediate power mandrel  24  has an inner bore  36 , wherein the inner bore  36  extends to channels  38 ,  40  for channeling of the drilling fluid through the apparatus  2 . The intermediate power mandrel  24  has on one end an outer thread means that will threadedly engage with the rotor-stator unit  18 . As understood by those of ordinary skill in the art, a lower power mandrel (not seen in this view) is included, and wherein the lower power mandrel is connected to the bit member so that the well can be drilled. 
     The inner portion  8  of the first housing  4  contains an upper radial shoulder  50  which in turn extends to inner splines  52 . The inner portion  8  also contains indentations  58 ,  60 , which cooperate and engage with the axial thrust bearings  30 ,  32 . The inner portion  8  also extends to the radial shoulder  62  which in turn extends to the enlarged diameter bore  8 . 
     The apparatus  2  also includes the anvil sub seen generally at  70 . The anvil sub  70  has an outer diameter surface  72  that extends to a second outer diameter surface  74 , which in turn extends to the radial shoulder  76 , wherein the radial shoulder  76  then extends to a splined surface  78  that will engage with inner splines  52  of the first housing  4 . The anvil sub  70  terminates at the stationary cam surface  82 , wherein the stationary cam surface  82  will cooperate and engage rotating cam surface  34 . 
     In the embodiment of  FIG. 1 , the apparatus  2  includes the radial bearing  90  for distributing radial loads during operation, wherein the radial bearing  90  is disposed between the inner bore  92  of the first housing  4  and the outer surface  94  of the upper power mandrel  16 . Another radial bearing  96  for distributing radial loads during operation is provided, and wherein the radial bearing  96  is disposed between the inner surface  98  and the outer surface  100  of the intermediate power mandrel  24 . 
       FIG. 1  also depicts the biasing member  102 , which may also be referred to as return spring  102  or spring  102 . The biasing member  102  will act against the radial shoulder  50  on one end and against the radial shoulder  76  on the other end. In operation, as the intermediate power mandrel  24  is turned by the downhole motor (motor not seen in this view), the upper power mandrel  16  is turned via the splines  103   a  of the intermediate power mandrel  24  engaging splines  103   b  located on upper power mandrel  16 . The rotating cam surface  34  is rotating thereby engaging the stationary cam surface  82 , wherein the cooperating cam surfaces  34 ,  82  cause the anvil sub  70  to move axially in a first direction and then in a second direction. The biasing member  102  acts to bias the anvil sub  70  into axial movement in the second direction after its axial movement in the first direction. In this way, any friction encountered by the workstring will be diminished by the axial movement of the downhole apparatus  2 . 
     Referring now to  FIG. 2 , a partial cross-sectional view of another embodiment of the up-drill apparatus  2  of the present disclosure will now be described. It should be noted that like numbers appearing in the various figures refer to like components. The apparatus  2  of FIG.  1  is similar to the apparatus  110  of  FIG. 2  and some of the similarities will not be repeated.  FIG. 2  further contains the rolling elements  112 ,  114  interfaced between the stationary cam surface  82  and the rotating cam surface  34 . Rolling elements  112 ,  114  may be referred to as rotating elements. In one preferred embodiment, rolling elements  112 ,  114  may be spherical members such as stainless steel ball bearings or ceramic balls. A feature of this disclosure is that use of the rolling elements  112 ,  114  allows for less of a direct impact on the stationary cam surface  82  and the rotating cam surface  34  when the surfaces  82  and  34  are interacting, which thereby produces less friction, abrasive wear, stress, and fatigue, which in turn increases the life of the surface  82  and surface  34 . 
     Referring now to  FIG. 3A , an illustration of a first embodiment of the cam surface  120  of the present disclosure will now be described. It should be noted that the cam surfaces of  FIGS. 3A-3D  may be either the rotating cam surface or the stationary cam surfaces since the two cam surfaces are reciprocating and mating. In  FIG. 3A , the cam surface  120  contains a series of surfaces, namely surface  122   a ,  122   b ,  122   c ,  122   d ,  122   e ,  122   f ,  122   g ,  122   h ,  122   i ,  122   j ,  122   k , wherein each surface has a rising or falling slope. The cam surface  120  has an undulating, mulitple segmented radial face.  FIG. 3B  is a circumferential profile view of the cam surface profile  120  seen in  FIG. 3A , and for instance surfaces  122   a ,  122   b ,  122   c ,  122   d ,  122   e ,  122   f ,  122   g , and  122   h  are shown. The cam surface  120  will engage a reciprocal cam surface (not shown here) during operation. 
       FIG. 3C  is a view of a second embodiment of the cam surface  124  of the present disclosure. This embodiment shows a cam low side  126   a  and a cam high side  126   b . The profile for this cam surface  124  is a smoother wave form. In one embodiment, surface  124  may be a sinusoidal waveform. It should be noted that both cam surfaces  120  and  124  may be referred to as an undulating profile. The cam surface  124  will engage a reciprocal cam surface (not shown here) during operation. 
     Referring now to  FIG. 3D , an illustration of a third embodiment of the cam surface  128  of the present disclosure will now be described. The cam surface  128  includes a ramp  130  (i.e. rising slope) that extends to a top end  132  (i.e. radially flat portion), which in turn extends to the upstanding portion  134 . The cam surface  128  may have two or more ramps; hence, there is also provided a ramp  136  that extends to a top end  138 , which in turn extends to the upstanding portion  140 . The cam surface  128  will engage a reciprocal cam surface (not shown here) during operation. 
       FIG. 4  is a view of one embodiment of reciprocal cams; more specifically,  FIG. 4  depicts the cam surface  120 , which in this embodiment is the rotating cam surface  120 . The reciprocal, stationary (i.e. non-rotating) cam surface  142  is shown, and wherein the stationary cam surface  142  is reciprocal and configured to cooperate with and engage with the rotating cam surface  120 . 
     Referring now to  FIG. 5 , a partial cross-sectional view of yet another embodiment of an up-drill apparatus  148  of the present disclosure will now be described.  FIG. 5  depicts the power mandrel  150  that will be operatively associated with a power section member, such as a rotor-stator means. The power mandrel  150  has an upper end  152  that may also be referred to as a “T-end”. The T-end has an upper surface  154  and a lower surface  156 , wherein the lower surface  156  is also referred to as the rotating cam surface  156 . The upper end  152  extends to the shaft portion seen generally at  158 , which in turn extends to the power section member (not shown here).  FIG. 5  also depicts the sub, seen generally at  160 , wherein the sub  160  is disposed within a housing  162 . The sub  160  has an outer surface  164  that has at one end the radial surface  166 , with the sub  160  having a bore  168   a  that extends to an expanded bore area  170 , which in turn extends to the internal radial surface end  172 . The sub  160  has at the second end the radial surface  174 . 
     As seen in  FIG. 5 , the sub  160  is contained within the inner portion  178  of housing  162 . The housing  162  is generally cylindrical and has a top portion  180  and a bottom portion  182 . The shaft portion  158  is disposed through the bore extension  168   b . As seen in  FIG. 5 , a cavity area  184  is formed between the radial surface  174  and the bottom portion  182  of the housing  162 . A biasing member, such as coiled spring  186 , wherein the biasing member  186  will act against the radial surface  174  and the internal surface  188  of the housing  162 . The internal radial surface  172  contains a cam profile surface  190 , such as stationary cam surface  82  as previously mentioned and seen in  FIG. 1 ; and, lower surface  156  contains a rotating cam surface  192 , such as rotating cam surface  34  and seen in  FIG. 1 . Rolling elements  194 ,  196  are also included, wherein the rolling elements  194 ,  196  may be spherical members, elongated spherical members, cylindrical members, other convex members, or concave members. In one embodiment, the spherical elements are stainless steel ball bearings or ceramic balls.  FIG. 5  also depicts the guide member  198  which is configured to contain the spherical members  194 ,  196  in a fixed position relative to one another. Note that guide member  198  contains an opening  200 , wherein opening  200  will have the shaft portion  158  disposed there through. Guide member  198  may also be referred to as cage or cage member. 
       FIG. 6  is a perspective view of the cage  198  having disposed therein the spherical members  194 ,  196 . Bore  200  used for placement of the shaft  158  is also shown. With the embodiment of  FIG. 6 , the spherical members  112 ,  114  are held in place during rotational operation of the cam surfaces. 
       FIG. 7A  illustrates another up-drill apparatus  201  including sub  202  having radial shoulder  203  and radial cam surface  204 . Apparatus  201  also includes power mandrel  205  having radial cam surface  206  designed to rotate. Rolling elements  207  and  208  are disposed between and in contact with radial cam surfaces  204  and  206 . Sub  202  and power mandrel  205  are at least partially contained within housing  209  such that radial cam surfaces  204 ,  206  and rolling elements  207 ,  208  are contained within housing  209 . Apparatus  201  may further include spring member  210  in contact with an upper shoulder of housing  209  and radial shoulder  203  such that spring member  201  biases housing  209  and sub  202  in opposite axial directions. In this embodiment having two rolling elements, rolling elements  207  and  208  may each be a spherical member having a diameter that is one-half of the inner diameter  211  of housing  209 , such that the spherical members are in contact with one another. Rolling elements  207  and  208  may be free to move between radial cam surfaces  204  and  206  as power mandrel  205  rotates. Rolling elements  207  and  208  may move in a circular path on radial cam surface  206  as power mandrel  205  rotates. This movement of rolling elements  207  and  208  may cause sub  202  to move in the axial direction. Power mandrel  205  may rotate continuously such that it rotates more than 360 degrees relative to sub  202 . 
       FIG. 7B  illustrates apparatus  201  having guide member  212  disposed between radial cam surfaces  204  and  206  for retaining rolling elements  207  and  208  in a fixed position relative to one another. 
       FIG. 8  shows guide member  212 , or cage  212 , with rolling elements  207  and  208 . Guide member  212  is optional in apparatus  201  of  FIGS. 7A and 7B  where rolling element  207  and  208  are each a spherical member having a diameter that is one-half of the inner diameter of housing  209 . However, a guide member, such as guide member  198  shown in  FIG. 6 , is preferred for apparatus  148  shown in  FIG. 5  due to the smaller relative diameter of rolling elements  194  and  196  and due to the presence of shaft  158  between rolling elements  194  and  196 . It should be understood that the downhole apparatus may include any number of rolling elements. Where three or more rolling elements are included, each rolling element may be in contact with two adjacent rolling elements. Alternatively, where rolling elements are not in contact with two adjacent rolling elements, a guide member may be used to retain each rolling element in a fixed position relative to the other rolling elements. The number of rolling elements included in the downhole apparatus may be equal to the number of high points or ramps on each of radial cam surfaces  204  and  206 . Each of the rolling elements of the downhole apparatus may be the same size. 
     Referring now to  FIG. 9 , a schematic illustration of the apparatus  2 , as depicted in  FIGS. 1 and 2 , wherein the apparatus  2  is disposed within a wellbore  220  will now be described. A workstring  222  is disposed within the wellbore  220 , wherein the workstring  222  is suspended from a rig  224 . The workstring  222  may be a tubular drill string or a coiled tubing string, and wherein this list is meant to be exemplary. The wellbore  220  includes the casing string  226  with the bore hole  228  extending therefrom.  FIG. 9  depicts the apparatus  2  being connected to a mud motor  230 , wherein the mud motor  230  is commercially available from Ashmin, LC. The mud motor  230  has the rotor-stator  18  unit previously mentioned, and wherein the lower rotating power mandrel  232 , operatively connected to the motor  230 , will ultimately turn the bit  234  via the circulation of the drilling fluid, as well understood by those of ordinary skill in the art. The bit  234  ultimately drills the bore hole  228 . Alternatively, apparatus  2  may include a power section member, such as a rotor-stator unit, separate from mud motor  230 . The workstring  222  may be stationary (i.e. non-rotating) or rotating during the drilling operation. 
     The embodiment of  FIG. 9  depicts the rolling elements  112 ,  114 . Hence, during operation, the cam surfaces (not shown here) will engage and cooperate thereby axially moving the workstring  222  relative to the mud motor  230  and bit  234  thereby preventing sticking of the workstring  222  which will in turn provide for a more efficient drilling of the wellbore  220 . 
       FIG. 10  illustrates apparatus  302  including rotating member  304  (sometimes referred to as rotating segment) and second member  306  (sometimes referred to as second segment). Rotating member  304  and second member  306  may each be at least partially disposed within housing  308 . Rotating member  304  may include first radial surface  310 . Second member  306  may include second radial surface  312  opposing first radial surface  310 . First radial surface  310  or second radial surface  312  may include a tapered surface as described above. In one embodiment, both radial surfaces  310 ,  312  include a tapered surface. The tapered surface may be an undulating waveform profile. 
     Apparatus  302  may include one or more rolling elements  314 . In one embodiment, apparatus  302  includes two rolling elements  314   a ,  314   b  as shown in  FIG. 10 . Each rolling element may have, but is not limited to, a spherical outer surface having a diameter that is approximately equal to one-half of an inner diameter of housing  308  such that rolling elements  314   a  and  314   b  are in constant contact with one another. It should be understood that apparatus  302  may include any number of rolling elements. The number of rolling elements included in the downhole apparatus may be equal to the number of high points or ramps on each of radial surfaces  310  and  312 . Each of the rolling elements may be the same size. 
     Rotating member  304  may rotate continuously relative to second member  306 , i.e., rotating member  304  may rotate more than 360 degrees relative to second member  306 . In one embodiment, second member  306  is a non-rotating member. Non-rotating member means that the member is not designed to rotate and the member is substantially non-rotating relative to the rotating member. In another embodiment, second member  306  is a member rotating at a different rotation rate than rotating member  304 . Rotation rate is the speed of rotation, which may be measured in units of rotations or revolutions per minute (RPM). In a further embodiment, second member  306  and rotating member  304  rotate in opposite directions. In all embodiments, as rotating member  304  rotates relative to second member  306 , rolling elements  314  move between first and second radial surfaces  310  and  312  thereby producing an axial movement of second member  306  relative to rotating member  304 . Rolling elements  314  may each move 360 degrees along a circular path relative to second radial surface  312 . Rolling elements  314  may also each move 360 degrees along a circular path relative to first radial surface  310 . The movement of rolling elements  314  on first and second radial surfaces  310  and  312  may occur simultaneously, such that rolling elements  314  move 360 degrees along a circular path relative to the first radial surface  310  and simultaneously move 360 degrees along a circular path relative to the second radial surface  312 . 
     It should be understood that apparatus  302  is not limited to the directional and inclinational arrangement shown. In other words, apparatus  302  will function as long as first radial surface  310  opposes second radial surface  31  with one or more rolling elements disposed between. Apparatus  302  may be arranged in an inverted vertical position relative to the one shown in these drawings. Apparatus  302  may also be arranged in a horizontal position or any other inclinational position. 
       FIG. 11A  is a cross-sectional view taken along line A-A in  FIG. 10  showing rolling elements  314   a ,  314   b  on first radial surface  310  disposed within housing  308 . 
       FIG. 11B  is an alternate cross-sectional view taken along line A-A in  FIG. 10 . In this embodiment, apparatus  302  includes three rolling elements, namely rolling elements  314   a ,  314   b ,  314   c.    
       FIG. 11C  is another alternate cross-sectional view taken along line A-A in  FIG. 10  showing apparatus  302  including four rolling elements, namely rolling elements  314   a ,  314   b ,  314   c ,  314   d.    
       FIG. 11D  is yet another alternate cross-sectional view taken along line A-A in  FIG. 10  showing apparatus  302  including ten rolling elements, namely rolling elements  314   a ,  314   b ,  314   c ,  314   d ,  314   e ,  314   f ,  314   g ,  314   h ,  314   i ,  314   j.    
     Each rolling element in  FIGS. 11B, 11C, and 11D  may be dimensioned such that each rolling element is in contact with two adjacent rolling elements. 
       FIG. 12  illustrates apparatus  302  having guide member  316  disposed between radial surfaces  310  and  312 . Guide member  316  may be used to contain rolling elements  314   a  and  314   b  in a fixed position relative to one another. 
       FIG. 13A  is a cross-sectional view taken along line B-B in  FIG. 12  showing rolling elements  314   a ,  314   b  retained by guide member  316  on first radial surface  310  disposed within housing  308 . In this embodiment, rolling elements  314   a ,  314   b  are dimensioned so that they are in constant contact with one another. 
       FIG. 13B  is an alternate cross-sectional view taken along line B-B in  FIG. 12 . In this embodiment, apparatus  302  includes two rolling elements  314   a ,  314   b , with the rolling elements dimensioned so that they are separated from one another. Guide member  316  retains rolling elements  314   a ,  314   b  in a fixed position relative to one another, such as 180 degrees apart. 
       FIG. 13C  is another alternate cross-sectional view taken along line B-B in  FIG. 12 . In this embodiment, apparatus  302  includes three rolling elements  314   a ,  314   b ,  314   c , with the rolling elements dimensioned so that they are separated from one another and retained in a fixed position relative to one another by guide member  316 , such as 120 degrees apart. 
       FIG. 13D  is yet another alternate cross-sectional view taken along line B-B in  FIG. 12 . In this embodiment, apparatus  302  includes four rolling elements  314   a ,  314   b ,  314   c ,  314   d , with the rolling elements dimensioned so that they are separated from one another and retained in a fixed position relative to one another by guide member  316 , such as 90 degrees apart. 
     It is to be understood that guide member  316  may be used with any number of rolling elements  314 . Use of guide member  316  is preferred when rolling elements  314  are dimensioned so that each rolling element does not constantly contact two adjacent rolling elements, such as in the embodiments shown in  FIGS. 13B, 13C, and 13D . 
     Apparatus  302  may be used in any number of tools, including downhole tools, in order to provide axial movement of a second member with the constant rotation of a rotating member. 
     Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.