Patent Abstract:
The drill device has a body with a front end and a rear end and which is connectable to the shaft of a drilling apparatus. A plurality of angularly spaced apart slots are formed in the exterior of the device which extend between the front and rear ends. Each slot has a lip extending from each of its front and rear ends respectively. A cutting member is provided for each of the slots with each cutting member having a connecting portion located in one of the slots and having a forward end and a rearward. Each connecting portion has a hook near its front and rear ends respectively for connection to the lips of the slot in which it is located.

Full Description:
This application is a continuation-in-part of U.S. application Ser. No. 09/912,977, filed Jul. 25, 2001, now U.S. Pat. No. 6,401,842, which claims the benefit of U.S. Provisional Patent Application No. 60/221,413, filed Jul. 28, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a drill device for a drilling a hole in the earth. 
     2. Description of the Prior Art 
     U.S. Pat. Nos. 4,281,723, 4,953,638, 5,423,388, 5,490,569, 5,957,222, 6,050,350, and 6,082,470 disclose drilling apparatus. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a drill device for drilling a hole in the earth. The drill device comprises a body having a front end and a rear end with a central axis extending between the front and rear ends and being connectable to a rotatable means. At least one slot is formed in the exterior of the body which is located outward relative to the central axis and which extends between the front and rear ends. The slot has a lip extending from its front and rear ends respectively. A cutting means is provided for the slot with the cutting means comprising a connecting portion located in the slot and having a forward end and a rearward end. The connecting portion comprises a hook near its front and rear ends respectively for connection to the lips of the slot. A removable stop means is positioned to prevent longitudinal movement of the connecting portion of the cutting means relative to the slot. 
     In another aspect, the plurality of angularly spaced apart slots are formed in the exterior of the body each for holding one of the cutting means. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 illustrates the top view of a drilling apparatus in the straight drilling mode. 
     FIG. 2 illustrates the side view of the drilling apparatus in the straight drilling mode. 
     FIG. 3 is a side cross sectional view of the parts of the apparatus that are locked longitudinally with the guide housings. 
     FIG. 4 is a top cross sectional view of the parts of the apparatus that are locked longitudinally with the guide housings. 
     FIG. 5 is a side cross sectional view of the parts of the apparatus that are locked longitudinally with the shaft. 
     FIG. 6 illustrates the top cross sectional view of the parts that are locked longitudinally with the shaft. 
     FIG. 7 is a cross sectional view of FIG. 1 taken along the lines  7 — 7  thereof. 
     FIG. 8 is a cross sectional view of FIG. 1 taken along the lines  8 — 8  thereof. 
     FIG. 9 is a top view of the drilling apparatus in the shifting mode. 
     FIG. 10 is a side view of the drilling apparatus in the shifting mode positioned in a curved hole. 
     FIG. 11 is a cross sectional view of FIG. 9 taken along the lines of  11 — 11  thereof. 
     FIG. 12 is the cross sectional view of FIG. 9 taken along the lines of  12 — 12  thereof. 
     FIG. 13 is a cross sectional view of FIG. 10 taken along the lines of  13 — 13  thereof. 
     FIG. 14 is a cross sectional view of FIG. 7 taken along the lines of  14 — 14  thereof. 
     FIG. 15 is a cross sectional view of FIG. 8 taken along the lines of  15 — 15  thereof. 
     FIG. 16 is a cross sectional view of FIG. 11 taken along the lines of  16 — 16  thereof. 
     FIG. 17 is a cross sectional view of FIG. 12 taken along the lines of  17 — 17  thereof. 
     FIG. 18 is a cross sectional view of FIG. 12 taken along the lines of  18 — 18  thereof when the clutch is in the neutral position. 
     FIG. 19 is a cross sectional view of FIG. 12 taken along the lines of  18 — 18  thereof, which is the same lines as FIG. 18 was taken from but when the shaft has been rotated in order to rotate the drilling apparatus. 
     FIG. 20 is a top view of the drilling apparatus in the major turn mode. 
     FIG. 21 is a side view of the drilling apparatus in the major turn mode. 
     FIG. 22 is a cross sectional view of FIG. 20 taken along the lines of  22 — 22  thereof. 
     FIG. 23 is a cross sectional view of FIG. 20 taken along the lines of  23 — 23  thereof. 
     FIG. 24 is a cross sectional view of FIG. 22 taken along the lines of  24 — 24  thereof. 
     FIG. 25 is a cross sectional view of FIG. 23 taken along the lines of  25 — 25  thereof. 
     FIG. 26 is a top view of the drilling apparatus in the minor turn mode. 
     FIG. 27 is a side view of the drilling apparatus in the minor turn mode. 
     FIG. 28 is a cross sectional view of FIG. 26 taken along the lines of  28 — 28  thereof. 
     FIG. 29 is a cross sectional view of FIG. 26 taken along the lines of  29 — 29  thereof. 
     FIG. 30 is a top view of the drilling apparatus in the partially pulled back mode. 
     FIG. 31 is a side view of the drilling apparatus in the partially pulled back mode. 
     FIG. 32 is a cross sectional view of FIG. 30 taken along the lines of  32 — 32  thereof. 
     FIG. 33 is a cross sectional view of FIG. 30 taken along the lines of  33 — 33  thereof. 
     FIG. 34 is an isometric view of the shifting cam. 
     FIG. 35 is 360-degree flat view of the exterior of the shifting cam 
     FIG. 36 is a 180-degree flat view of the shifting cam and the shifting cam follower in the straight drilling mode. 
     FIG. 37 is a 180-degree flat view of the shifting cam lug contacting the shifting cam groove intersection. 
     FIG. 38 is a 180-degree flat view of the shifting cam with the shifting cam followers in full rearward position. 
     FIG. 39 is a 180-degree flat view of the shifting cam with the shifting cam follower lug contacting an intersection of the shifting cam grooves. 
     FIG. 40 is a 180-degree flat view of the shifting cam with the shifting cam follower in transition between the full rearward position and the full forward position. 
     FIG. 41 is a 180-degree flat view of the shifting cam with the shifting cam follower in the fully forward position. 
     FIG. 42 is a 360-degree flat view of the shifting cam with the shifting cam follower lugs contacting an intersection of the shifting cam grooves. 
     FIG. 43 is a 360-degree flat view of the shifting cam with the shifting cam followers in transition between the major turn position and the rearward position before drilling straight. 
     FIG. 44 is a 360-degree flat view of the shifting cam with the shifting cam followers by-passing the by-pass groove of the shifting cam. 
     FIG. 44A is a 180-degree flat view of the shifting cam with the shifting cam follower lug stopped by the end of the shifting cam groove. 
     FIG. 44B is a 180-degree flat view of the shifting cam with the shifting cam follower lug contacting the intersection of the grooves in the shifting cam. 
     FIG. 44C is a 180-degree flat view of the shifting cam with the shifting cam follower in the straight position. 
     FIG. 44D is a 180-degree flat view of the shifting cam with the shifting cam follower contacting an intersection of the shifting cam grooves. 
     FIG. 44E is a 180-degree flat view of the shifting cam with the shifting cam follower in the full rearward position. 
     FIG. 44F is a 180-degree flat view of the shifting cam with the shifting cam follower lug contacting an intersection of the shifting cam grooves. 
     FIG. 44G is a 180-degree flat view of the shifting cam with the shifting cam follower&#39;s forward displacement halted in preparation to start the minor turn sequence. 
     FIG. 44H is a 180-degree flat view of the shifting cam with the shifting cam follower contacting an intersection of the shifting cam grooves. 
     FIG.  44 (I) is a 180-degree flat view of the shifting cam with the shifting cam follower fully rearward in the minor turn sequence. 
     FIG. 44J is a 360-degree flat view of the shifting cam with the shifting cam followers in transition from the fully rearward position to the minor turn position. 
     FIG. 44K is a 360-degree flat view of the shifting cam with the shifting cam followers exiting the by-pass groove. 
     FIG. 44L is a 360-degree flat view of the shifting cam with the shifting cam followers heading toward the minor turn stop. 
     FIG. 44M is a 360-degree flat view of the shifting cam with the shifting cam follower lugs stopped by the minor turn stop. 
     FIG. 44N is a 180-degree flat view of the shifting cam with the shifting cam follower in transition between the minor turn and the rearward stop before going straight. This view shows the shifting cam follower missing the by-pass groove. 
     FIG.  44 (O) is a 180-degree flat view of the shifting cam with the shifting cam follower in transition between the minor turn and the rearward stop before going straight. 
     FIG. 44P is a 180-degree flat view of the shifting cam with the shifting cam follower in the fully rearward position before going straight. 
     FIG. 45 is an isometric view of the clutch stop. 
     FIG. 45A is an enlargement of the clutch stop lug. 
     FIG. 46 is an isometric view of the front of the female clutch member. 
     FIG. 47 is an isometric view of the rear of the female clutch member. 
     FIG. 48 is an isometric view of the rear of the male clutch member. 
     FIG. 49 is a cutout section of the guide housing showing the clutch members in a relaxed position. 
     FIG. 50 is a cutout section of the guide housing showing the clutch members engaging each other. 
     FIG. 51 is a front view of the shaft retainer cut to hold the rotational cutting means. 
     FIG. 52 is a side view of the shaft retainer. 
     FIG. 53 is a rear view of the shaft retainer. 
     FIG. 54 is a cross sectional view of FIG. 52 taken along the line  54 — 54  thereof. 
     FIG. 55 is a side view of the assembled rotational cutting means. 
     FIG. 56 is a front view of the assembled rotational cutting means. 
     FIG. 57 is a rear view of the assembled rotational cutting means. 
     FIGS. 58-65 shows the coupling procedure of the rotational cutting means. 
     FIG. 66 is a cross sectional view of the front end of the drilling apparatus showing the magnetic displacement device in use. 
     FIG. 67 is a cross sectional view of FIG. 66 taken along the line  67 — 67  thereof. 
     FIG. 68 is an isometric view of the transmitter housing with magnetic sensitive wires positioned to indicate longitudinal displacement of the shaft. 
     FIG. 69 is a cross sectional view of the rear of the apparatus using a longer clutch means. 
     FIG. 70 is a top view of the drilling apparatus with a third housing attached. 
     FIG. 71 is a side view of the drilling apparatus with a third housing attached. 
     FIG. 72 is a cross sectional view of FIG. 70, using a standard transmitter, taken along the lines  72 — 72  thereof. 
     FIG. 73 is a cross sectional view of FIG. 70, using a Wireline transmitter, taken along the lines  73 — 73  thereof. 
     FIG. 74 is an illustration of the alternative drilling apparatus using a percussion type cutting means in the straight drilling mode. 
     FIG. 75 is an illustration of the alternative drilling apparatus using a percussion type cutting means in the shifting mode. 
     FIG. 76 is an illustration of the alternative drilling apparatus using a percussion type cutting means in the turning mode. 
     FIG. 77 is an illustration of the alternative drilling apparatus using a rotational type cutting means in the straight drilling mode. 
     FIG. 78 is an illustration of the alternative drilling apparatus using a rotational type cutting means in the shifting mode. 
     FIG. 79 is an illustration of the alternative drilling apparatus using a rotational type cutting means in the turning mode. 
     FIG. 80 is a cross sectional view of FIG.  74  and FIG. 77 taken along the lines of  80 — 80  thereof. 
     FIG. 81 is a cross sectional view of FIG.  75  and FIG. 78 taken along the lines of  81 — 81  thereof. 
     FIG. 82 is a cross sectional view of FIG.  76  and FIG. 79 taken along the lines of  82 — 82  thereof. 
     FIG. 83 is a cross sectional view of FIG. 79 taken along the lines of  83 — 83  thereof. 
     FIG. 84 is a 180-degree flat view of the alternative-shifting cam with the alternative-shifting cam follower in the fully forward position. 
     FIG. 85 is a 180-degree flat view of the alternative-shifting cam with the alternative-shifting cam follower contacting an intersection of the alternative shifting cam grooves. 
     FIG. 86 is a 180-degree flat view of the alternative-shifting cam with the alternative-shifting cam follower in transition between fully forward and fully rearward positions. 
     FIG. 87 is a 180-degree flat view of the alternative-shifting cam with the alternative-shifting cam follower in the fully rearward position. 
     FIG. 88 is a 180-degree view of the alternative-shifting cam with the alternative-shifting cam follower contacting an intersection of the alternative-shifting cam grooves. 
     FIG. 89 is a 180-degree flat view of the alternative-shifting cam with the alternative-shifting cam follower in transition between the fully rearward position and the straight position. 
     FIG. 90 is a 180-degree flat view of the alternative-shifting cam with the alternative-shifting cam follower in the straight position. 
     FIG. 91 is a 180-degree flat view of the alternative-shifting cam with the alternative-shifting cam follower in contact with an intersecting groove. 
     FIG. 92 is a 180-degree flat view of the alternative-shifting cam with the alternative-shifting cam follower in transition from the straight position to the fully rearward position. 
     FIG. 93 is a 180-degree flat view of the alternative-shifting cam with the alternative-shifting cam follower in the fully rearward position. 
     FIG. 94 is a 180-degree flat view of the alternative-shifting cam with the alternative-shifting cam follower contacting an intersection of the grooves. 
     FIG. 95 is a 270-degree flat view of the alternative-shifting cam with the alternative-shifting cam follower in transition between fully rearward and fully forward positions. 
     FIG. 96 is the rear view of a hole-opener body. 
     FIG. 97 is a cross sectional view of the hole-opener body taken along the lines  97 — 97  thereof. 
     FIG. 98 is a front view of the hole-opener body. 
     FIGS. 99-104 shows the rotational cutting means being mounted on to the hole-opener body. 
     FIG. 105 shows the side view of the hole-opener body with the rotational cutting means mounted thereto. 
     FIG. 106 illustrates the hole opener device of FIG. 105 in use enlarging a hole. 
     FIG. 107 illustrates a single modified wing type cutting means installed in a single slot of a shaft retainer. 
     FIG. 108 illustrates a single roller cone but attached to a plate holding mechanism installed in a single slot of a shaft retainer. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1-65 of the drawings, the apparatus comprises a shaft  101  having a rear end  101 R connectable to a drilling system  103  and a rotational cutting means  105  connectable to the front end  101 F. The shaft  101  extends through a front housing  111  and a rear housing  113 . The drilling system is a conventional system that can rotate and push the shaft  101  forward for drilling purposes and it can also pull the shaft  101  rearward. Additional stem members can be attached to the rear  101 R of the shaft  101  and to the drilling system  103  as the hole being drilled gets longer or deeper. The shaft  101  can rotate within each of units  111  and  113 , and can move forward a small distance to a drilling position and rearward a small distance to a shifting position relative to units  111  and  113 . Units  111  and  113  cannot rotate relative to each other, but they can bend or pivot lengthwise relative to each other, as shown in FIGS. 21-23 and  27 - 29 . 
     A front ball joint  115  with pivot pins  117  located at the front of unit  111  supports unit  111  on the front of the shaft  101 F. A middle ball joint  119  with a rear end  119 R connects the rear of unit  111  with the front of unit  113 . A rear ball joint  121  with pivot pins  121 A similar to the front ball joint  115  supports the rear of unit  113  on the rear of shaft  101 R. 
     A main cam  123  and a main cam follower  163  are employed in unit  113  to cause the apparatus to drill straight as shown in FIGS. 1 and 2 or to tilt or pivot units  111  and  113  relative to the shaft  101  as shown in FIGS. 21-23 and  27 - 29  to cause the front of the shaft  101 F to turn up, down, left, or right or any fraction thereof while drilling operations are being carried out. A shifting cam  145  is also located in unit  113  for the purpose of regulating the straight and turn drilling by regulating the amount of longitudinal displacement between the main cam  123  and the main cam follower  163 . 
     For reference, in the drawings, the top of the drilling apparatus is on the inside of the radius being drilled, such that if the hole is being turned up relative to the earth, the top of the drilling apparatus is up relative to the earth. Likewise if the bore is being turned downward relative to the earth, the drilling apparatus is turned upside down, and so on. Referring to FIG.  3  and FIG. 4, the front housing  111  has fixedly attached to it, a front socket  127 , a transmitter case  129 , a middle socket  131 , and a front wear pad  133 . The front socket  127  encases the front ball  115  so that the front housing  111  may pivot relative to the shaft  101 . The transmitter case  129  is accessible through a cutout  135  in the side of the front housing  111 . The door  129 D covers the transmitter  137 . The transmitter case  129  holds the compartment for the transmitter  137  employed by the drilling apparatus. The middle socket  131  encases the middle ball  119  so that the front housing  111  may pivot relative to the rear housing  113 . The middle socket  131  and the middle ball  119  are pinned together so that they cannot rotate relative to each other, such that the two housings  111  and  113  cannot rotate relative to each other. The front wear pad  133  is located on the bottom of the drilling apparatus, such that it pushes against the bore wall  179  to cause the drilling apparatus to turn. The rear of the middle ball  119 R is fixedly attached to the front of the rear housing  113 . The rear housing  113  has fixedly attached to it a main cam  123 , a stop plate  141 , a shifting cam bushing  143 , a stop bushing  167 B, a clutch stop  147 , a rear socket  149 , and a rear wear pad  151 . The shifting cam bushing  143  supports a shifting cam  145 . The shifting cam  145  is free to rotate, but is locked longitudinally relative to the rear housing  113 . The clutch stop  147  is fixedly attached to the housing  113  and limits the rotational and forward movement of a female clutch member  153 . The rear socket  149  limits the rearward movement of the female clutch member  153 . The female clutch member  153  is free to rotate relative to the rear housing  113  only enough to allow the male clutch member  171  to engage with female clutch member  153  without regards to their starting rotational orientation. 
     Referring to FIGS. 5 and 6 the shaft  101  has attached to it a shaft retainer  155  upon which; in this case, a rotational cutting means  105  is mounted. The cutting means  105  may be a conventional rotary type as shown or it may be a hammering system that is commonly employed in harder strata and illustrated in FIGS. 74-76. Behind the shaft retainer  155  are two sleeves  157  and  159  that rotate with the shaft  101  and hold the other components longitudinally in place. Behind the sleeves  157  and  159  are a thrust bearing  161 , a main cam follower  163 , a cam follower spacer  165 , a thrust bearing  169 , and a male clutch member  171 . The cam follower  163  and cam follower spacer  165  are free to rotate relative to the shaft  101 , but are tied longitudinally to the shaft  101  by the shaft retainer  155 , the two sleeves  157  and  159 , the thrust bearings  161  and  165  and the shoulder  101 S of the shaft  101 . The shaft  101  can rotate relative to the cam follower  163  and spacer  165 . Mounted on the rear of the shaft  101 R is a rearward cutter  173 . The rearward cutter  173  contains threads for accepting a thread adapter  175  that joins the drilling apparatus to the drill string and ultimately the drilling system  103 . Two shifting cam followers  177 A and  177 B are mounted 180 degrees from each other and 90 degrees from the cam follower lugs  163 S and  163 L on the outside of the cam follower  163 . The shifting cam followers  177 A and  177 B are free to pivot relative to the cam follower  163 , but are locked longitudinally to the cam follower  163  by pins  163 P. The shifting cam followers  177 A and  177 B are locked rotationally to the housing  113  but are free to move longitudinally relative to the housing  113 . The followers  177 A and  177 B cannot rotate relative to the housing  113 . 
     Referring to FIGS. 3-44 the main cam  123  has two slots cut into it, 180 degrees apart. The bottoms of the slots stay relatively parallel to each other. The bottom of the slots start out in the rear of the main cam  123  close to the bottom of the drilling apparatus and progress in several stages close to the top of the drilling apparatus as they progress to the front. The slots accept the main cam follower lugs  163 S and  163 L. The sides of slots keep the main cam follower  163  rotationally engaged to the rear housing  113  for rotation with the rear housing  113  as well as giving support for side loaded pressure placed on the drilling apparatus. The large cam follower lug  163 L is located on the bottom of the drilling apparatus, while the small cam follower lug  163 S is located on the top of the drilling apparatus. As the main cam follower  163  is displaced forward relative to the main cam  123 , the main cam follower lugs  163 S and  163 L follow the slots in the main cam  123 . This causes the front of the rear housing  113  and the rear of the front housing  111  to pivot downward away from the shaft  101 , such that the bore wall  179  is pushed on by the wear pad  133  and the drilling apparatus is caused to change directions. When the main cam follower  163  is displaced fully rearward, the front of the rear housing  113  and the rear of the front housing  111  are pivoted upward toward the shaft  101 . This causes the wear pad  133  to be pulled in as close as possible to the shaft  101 . 
     Referring to FIGS. 34-44P, the shifting cam  145  and shifting cam followers  177 A and  177 B regulate the amount of longitudinal displacement that the main cam  123  and main cam follower  163  undergo. In FIGS. 35-44P the exterior surface of the cam  145  is shown laid out flat. The two cam followers  177 A and  177 B are located 180 degrees apart. In FIGS. 35,  42 - 44 , and  44 J- 44 M, 360 degrees of the cam is shown and in FIGS. 42-44 and  44 J- 44 M both cam followers  177 A and  177 B are shown. In FIGS. 36-41,  44 A- 44 (I) and  44 N- 44 P only 180 degrees of the cam  145  is shown and only one cam follower  177 B is shown although it is to be understood that the complete cam of FIGS. 34 and 35 and both followers  177 A and  177 B will be employed. In FIGS. 36-44P the horizontal arrows depict the direction of longitudinal travel of the followers  177 A and  177 B and the vertical arrows next to the cam  145  depict the direction of rotation of the cam  145 . In FIGS. 36-44P, rearward movement of the followers  177 A and  177 B is to the right and forward movement of the followers  177 A and  177 B is to the left. The lugs  177 AL and  177 BL of the cams  177 A and  177 B can be moved between positions displaced fully rearward as shown by follower  177 B in FIG.  38  and to positions fully displaced forward as shown by follower  177 B in FIG.  41  and to intermediate positions. Grooves  145 A- 145 E are cut into the outside of the shifting cam  145  at an angle such that when the shifting cam followers  177 A and  177 B are displaced longitudinally they contact the walls of the grooves  145 A- 145 E, which rotate the shifting cam  145 . Furthermore, the lugs  177 AL and  177 BL on the shifting cam followers  177 A and  177 B are shaped in such away as to ride along the walls of the grooves  145 A- 145 E and to enter into an intersecting groove  145 AB- 145 DE when the appropriate displacement and rotational positioning is achieved. 
     FIG. 36 shows the shifting cam follower  177 B in the straight drilling position. In this position the shifting cam followers  177 A and  177 B, and thus the main cam follower  163 , cannot progress any further forward relative to the shifting cam  145 , and thus the main cam  123 , because the shifting cam follower lugs  177 AL and  177 BL are in contact with end of the shifting cam grooves  145 E. Displacing the shifting cam followers  177 A and  177 B rearward causes them to contact the next set of intersecting grooves  145 DE (FIG.  37 ). When the shifting cam followers  177 A and  177 B are displaced further rearward the shifting cam  145  is forced to rotate by the shifting cam follower lugs  177 AL and  177 BL pushing on the walls of the shifting cam grooves  145 D. The contact of the main cam follower lugs  163 S and  163 L and the stop ring  141  halt the rearward longitudinal displacement of the shifting cam followers  177 A and  177 B relative to the shifting cam  145  (FIG.  38  and FIG.  12 ). In this longitudinal position the clutch members  153  and  171  are engaged and the housing  113  may be rotated with the shaft  101 . When the desired rotational position is achieved, the shifting cam followers  177 A and  177 B can be moved forward relative to the shifting cam  145  until they contact the next set of intersecting grooves  145 AD (FIG.  39 ). As the shifting cam followers  177 A and  177 B are further displaced forward relative to the shifting cam  145 , the shifting cam follower lugs  177 AL and  177 BL push on the wall of the shifting cam grooves  145 A forcing the shifting cam  145  to rotate relative to the housing  113  (FIG.  40 ). The shifting cam followers  177 A and  177 B do not rotate relative to the housing  113  because they are held rotationally locked to the housing  113  by the shifting cam bushings  143 . The contact of the stop washer  167  and the stop bushing  167 B halts the further forward displacement of the shifting cam followers  177 A and  177 B relative to the shifting cam  145  as well as the forward displacement of the main cam follower  163  relative to the main cam  123  (FIG.  41  and FIG.  23 ). In this position the tightest radius is being drilled. Displacing the shifting cam followers  177 A and  177 B rearward causes them to contact yet another set of intersecting grooves  145 AC (FIG.  42 ). Further rearward displacement causes the shifting cam follower lugs  177 AL and  177 BL to push on the walls of shifting cam grooves  145 C, forcing the shifting cam  145  to rotate relative to the housing  113  (FIG.  43 ). FIG. 44 shows the shifting cam followers  177 A and  177 B moving passed the by-pass groove  145 B without entering it. This is possible by the widening of the grooves  145 C in this location. The contact of the end of the shifting cam grooves  145 C and the shifting cam follower lugs  177 AL and  177 BL stops the rearward displacement of the shifting cam followers  177 A and  177 B relative to the shifting cam  145  (FIG.  44 A). In this embodiment the clutch members  171  and  153  are not engaged in this position, allowing the operator to know that upon pushing forward he will be drilling straight because the next intersecting groove leads to the straight position. Displacing the shifting cam followers  177 A and  177 B forward causes the shifting cam follower lugs  177 AL and  177 BL to contact the intersections of yet another set of shifting cam grooves  145 CE (FIG.  44 B). Further forward displacement of the shifting cam followers  177 A and  177 B causes the shifting cam follower lugs  177 AL and  177 BL to push on the shifting cam groove walls, which causes the shifting cam  145  to rotate relative to the housing  113 . The contact of the shifting cam follower lugs  177 AL and  177 BL and the end of the shifting cam grooves  145 E stops the forward displacement of the shifting cam followers  177 A and  177 B relative to the shifting cam  145  and thus, the forward displacement of the main cam follower  163  relative to the main cam  123  (FIG.  44 C). In this position the housings  111  and  113  are virtually parallel with the shaft  101 , thus causing zero effect on the direction of travel, which allows the drilling apparatus to drill straight. In this embodiment the clutch members  171  and  153  are not engaged, which allows the shaft  101  to rotate without rotating the housing  113 . While drilling straight the housings  111  and  113  slide through the bore being drilled. Rearward displacement of the shifting cam followers  177 A and  177 B causes them to contact the next set of intersecting grooves  145 DE (FIG.  44 D). Further rearward displacement causes the shifting cam  145  to rotate relative to the housing  113 . Contact between the main cam follower lugs  163 S and  163 L and the stop plate  141  stops the rearward displacement between the shifting cam followers  177 A and  177 B and the shifting cam  145  (FIG.  44 E and FIG.  12 ). Forward displacement of the shifting cam followers  177 A and  177 B causes the shifting cam follower lugs  177 AL and  177 BL to contact the next set of intersecting grooves  145 AD (FIG.  44 F). Further forward displacement of the shifting cam followers  177 A and  177 B causes the shifting cam follower lugs  177 AL and  177 BL to push on the shifting cam groove walls causing the shifting cam  145  to rotate relative to the housing  113 . By halting the forward displacement of the shifting cam followers  177 A and  177 B relative to the shifting cam  145  before the shifting cam follower lugs  177 AL and  177 BL are displaced enough to enter the intersecting grooves  145 AC, but after they have passed the entrance of the by-pass grooves  145 AB, the operator has a choice to either drill straight or at least drill a lesser deviated hole (FIG.  44 G). The forward displacement of the shifting cam followers  177 A and  177 B may be stopped by the operator or by the hard surface of the bore wall. For example, if the cutting means  105  or  247  is not activated, by either the rotation of the shaft or the supply of a compressed medium, such as air or water, after the main cam follower  163  is displaced forward enough to put sufficient pressure on the housing  113  to deflect it against the bore wall, the apparatus will not cut off to the side and thus the pressure from the wear pads  151  and  133  and the non-activated cutting means  105  or  247  will halt the forward displacement of the main cam follower  163  relative to the main cam  123  and thus the shifting cam followers  177 A and  177 B relative to the shifting cam  145 . Rearward displacement of the shifting cam followers  177 A and  177 B relative to the shifting cam  145  causes the shifting cam follower lugs  177 AL and  177 BL to contact the shifting cam groove walls causing the shifting cam  145  to rotate. This time the shifting cam  145  is rotating in the opposite direction from what it normally rotates. Further rearward displacement causes the shifting cam follower lugs  177 AL and  177 BL to contact the intersections of the bypass grooves  145 AB (FIG.  44 H). Still more rearward displacement of the shifting cam followers  177 A and  177 B causes the shifting cam  145  to rotate in its normal direction. The contact of the main cam follower lugs  163 S and  163 L and the stop ring  141  halts the rearward displacement (FIG.  44 (I) and FIG.  12 ). In this position the clutch members  153  and  171  are engaged and the housing  113  may be rotated if desired. Forward displacement of the shifting cam followers  177 A and  177 B causes the shifting cam follower lugs  177 AL and  177 BL to contact the next set of intersecting grooves  145 BA. Further forward displacement of the shifting cam followers  177 A and  177 B causes the shifting cam  145  to rotate in its normal direction (FIG.  44 J and FIG.  44 K). The shifting cam  145  is rotated until the shifting cam follower lugs  177 AL and  177 BL exit the by-pass grooves  145 B (FIG.  44 L). The continued forward displacement of shifting cam followers  177 A and  177 B causes the shifting cam follower lugs  177 AL and  177 BL to enter into a set of short grooves  145 M, which stops the forward displacement of the shifting cam followers  177 A and  177 B relative to the shifting cam  145  (FIG.  44 M). In this position the main cam follower  163  is displaced forward relative to the main cam  123  enough to deflect the housings  111  and  113  only part of their total deflection capabilities (FIGS.  27 - 29 ). If the operator chooses to drill forward the drilling apparatus will turn at a lesser degree than would otherwise be possible. If the operator chooses not to drill forward he can continue to manipulate the drill stem in order to position the drilling apparatus in the desired mode. Rearward displacement of the shifting cam followers  177 A and  177 B causes the shifting cam follower lugs  177 AL and  177 BL to contact the walls of shifting cam groove  145 C on the other side of the by-pass groove  145 B thus allowing the shifting cam  145  to be rotated in the normal direction (FIG.  44 N). Further rearward displacement of the shifting cam followers  177 A and  177 B relative to the shifting cam  145  causes the shifting cam follower lugs  177 AL and  177 BL to push on the shifting cam groove wall, which causes the shifting cam  145  to rotate relative to the housing  113  (FIG.  44 (O)). Contact between the shifting cam follower lugs  177 AL and  177 BL and the end of the shifting cam grooves  145 C stops the rearward displacement of the shifting cam followers  177 A and  177 B relative to the shifting cam  145  (FIG.  44 P). Further longitudinal displacement causes this sequence to repeat. 
     Referring to FIGS. 1,  2 ,  7 ,  8  and  36 , when the shifting cam followers  177 A and  177 B are stopped by shifting cam grooves  145 E the drilling apparatus is drilling with the main cam follower  163  only partially displaced relative to the main cam  123 , such that a straight bore is produced. 
     Referring to FIGS. 9-13,  38 ,  44 E, and  44 (I) when the shifting cam followers  177 A and  177 B are allowed to regress backward without hindrance from the shifting cam  145  the longitudinal displacement of the main cam follower  163  relative to the main cam  123  is stopped by the main cam follower lugs  163 S and  163 L and the stop plate  141 . In this position all of the parts of the drilling apparatus are rotationally locked by the engagement of the clutch means  171  and  153 . 
     Referring to FIG. 10 the bore illustrated is curved downwards while the drilling apparatus is in the shifting position and oriented to drill upwards. The rear of the front housing  111  and the front of the rear housing  113  are bent upward allowing the drilling apparatus to be rotated a full 360 degrees in a tighter radius bore than might otherwise be possible. This allows the drilling apparatus to be with drawn through a smaller radius bore without becoming stuck. 
     Referring to FIGS. 20-25 and  41  when the shifting cam followers  177 A and  177 B are allowed to progress forward unimpeded by the shifting cam  145  the forward displacement of the main cam follower  163  relative to the main cam  123  is stopped by the contact of the stop washer  167  and the stop bushing  167 B. In this position the drilling apparatus is producing the tightest turn possible. 
     Referring to FIGS. 21-23 and  27 - 29  the middle wear pad  133  is mounted on the rear of the front housing  111  such that when the rear of the front housing  111  is bent downward the wear pad  133  is forced against the bottom of the bore  179 , which pushes laterally on the drilling apparatus until the rear wear pad  151  hits the opposite side of the bore  179 , then the front of the drilling apparatus is pivoted toward the opposite side changing the direction of travel. 
     Referring to FIGS. 26-29 and  44 M, when the shifting cam followers  177 A and  177 B are stopped by shifting cam groove  145 M the drilling apparatus is drilling with the main cam follower  163  only partially displaced relative to the main cam  123 , such that a larger radius is drilled. 
     Referring to FIGS. 30-33,  44 A and  44 P, when the shifting cam followers  177 A and  177 B are stopped by shifting cam groove  145 C the male clutch member  171  is halted from engaging the female clutch member  153  such that the housing  113  cannot be rotated when the shaft is rotated. This lets the operator know that upon pushing forward he will be drilling straight. 
     Referring to FIGS.  18 , 19  and  45 - 50  the clutch stop  147  has two lugs  147 L protruding toward the rear of the drilling apparatus. Each lug is identical. Each has a cam groove  147 C cutout that acts like a cam and a pin  147 P protruding radially outward. The pin  147 P is designed to hold the end of one of two elastic bands  153 R or  153 S whose other end is attached to one of two cam follower pins  153 P, that are attached to the clutch ring  153 . The elastic bands may be o-rings made from a suitable elastomer. The clutch ring  153  has two cutouts  153 C cut into its outer edge. Within these cutouts  153 C are mounted the two cam follower pins  153 P that act as cam followers. The interior of the ring  153  has teeth  153 T protruding toward the center. Each tooth  153 T has a beveled surface  153 B on its forward face. Cut radially around the clutch rings  153  outer edge is a groove  153 G that is wide enough and deep enough for the unobstructed acceptance of the elastic bands  153 R and  153 S. A male clutch member  171  is mounted fixedly on the shaft  101 . On the outer edge of the male clutch member are mounted teeth  171 T. Each tooth  171 T has a beveled surface  171 B facing rearward. 
     FIG. 49 shows the clutch assembly in a relaxed state. The housing  113  supports the clutch ring  153  and the clutch stop  147 . The male clutch member  171  is forward of the clutch ring  153 . The clutch ring  153  is positioned so that the lugs  147 L on the clutch stop  147  are located in and engaged with the cutouts  153 C on the clutch ring  153 . The cam pins  153 P are positioned in the cam groove  147 C. The elastic bands  153 R and  153 S are position so that one end is held by a cam pin  153 P and stretches through the groove  153 G to the pin  147 P that is mounted on the opposite lug  147 L. In this relaxed state, the elastic bands  153 R and  153 S keep the clutch ring  153  rotated clockwise as seen from the rear of the drilling apparatus. Being fully rotated clockwise the cam follower pins  153 P are positioned in the apex of the cam grooves  147 C and the clutch ring  153  is fully forward, resting against the face of the clutch stop  147 . 
     When the male clutch member  171  is pulled rearward, it will either enter into the clutch ring  153  without any interference, or the respective teeth  153 T and  171 T will hit. If the teeth  153 T and  171 T hit, the clutch ring  153  will be forced rearwards. This will cause the cam follower pins  153 P to contact the cam grooves  147 C, which will force the clutch ring  153  to rotate counter-clockwise as seen from the rear. As the counter clockwise rotation is taking place the elastic bands  153 R and  153 S are stretching and gaining potential energy. The rearward displacement of the clutch ring  153  is stopped when it contacts the rear ball socket  149 . By the time the clutch ring  153  has been displaced fully rearward the cam groove  147 C has exhausted its influence on the cam follower pin  153 P (FIG.  50 ). In this position the beveled surfaces  153 B and  171 B on the clutch rings teeth  153 T and the male clutch members teeth  171 T will be rotationally aligned so that any further rearward displacement of the male clutch member  171  relative to the clutch ring  153  will cause these surfaces  153 B and  171 B to push on each other, which will continue the counter-clockwise rotation of the clutch ring  153  relative to the clutch stop. The counter-clockwise rotation will stop when the clutch ring  153  and the male clutch member  171  are located such that each tooth  171 T is located between adjacent teeth  153 T. 
     In this position, the male clutch member  171  may be rotated in either direction to rotate the clutch ring  153  and hence the housing  113  in either direction. If it is rotated counter clockwise, the clutch ring  153  will be rotated relative to the housing  113  until the clutch stop lugs  147 L contact the edges of the cutouts  153 C on the clutch ring  153 . Further counter-clockwise rotation of the clutch ring  153  will rotate the housing  113  counter-clockwise. If the male clutch member  171  is rotated clockwise, the cam follower pins  153 P will contact the cam grooves  147 C, which will force the clutch ring  153  forward. The clutch ring  153  will stop being rotated relative to the housing  113  when the edges of the cutouts  153 C in the clutch ring  153  contacts the clutch stop lugs  147 L. In this position the clutch ring  153  is back in its starting position. Further clockwise rotation of the clutch ring  153  will rotate the housing  113  clockwise. If the male clutch member  171  has moved forward enough to disengage with the clutch ring  153  but has not rotated the clutch ring  153  clockwise enough to reposition the clutch ring  153  in its starting position, the elastic bands  153 R and  153 L will contract. This will rotate the clutch ring  153  clockwise causing the cam follower pin  153 P to contact the cam groove  147 C. As the cam follower pin  153 P is rotated clockwise it is being forced forward by the cam groove  147 C. The rotation and the forward travel relative to the housing  113  stop when the edges of the cutouts  153 C on the clutch ring  153  contact the clutch stop lugs  147 L. In this position the clutch ring  153  is in its starting position. 
     Referring to FIGS. 51-65 the rotational cutting means  105  are individual wings positioned on the shaft retainer  155  in radial positions to form a drill bit. Three slots  155 S are cut lengthwise into the shaft retainer  155 . On the front and rear of the shaft retainer  155  are cut six slots  155 LS perpendicular to the slots  155 S such that they leave behind a lip  155 L corresponding to the front and rear of each slot  155 S. Two dowel-pin holes  155 P are drilled perpendicular to each slot  155 S such that they are in a position to allow dowel-pins  155 D to lock the rotational cutting wings  105  in place. The dowel-pin holes  155 P are drilled so that the dowel-pins  155 D can be inserted and extricated from the direction of rotation such that upon rotation in the proper and common direction, the dowel-pins  155 D will not be pushed out of the dowel-pin holes  155 P. Smaller diameter hole portions are formed in the member  155  on the side of each slot to allow the dowel-pins to be pressed out. On the front of the shaft retainer are three openings  155 H that allow water or other medium to escape from inside the shaft  101 . The individual cutting wings  105  have a section behind the actual cutting area  105 C that is called the shank  105 S. The shank  105 S is of a shape that will fit into one of the slots  155 S with little clearance. On the front is a front hook  105 F. On the rear is a rear hook  105 R. A second cutting surface  105 B faces toward the rear. Two dowel-pin holes  105 D are drilled in the middle of the shank  105 S. FIGS. 58-65 show the rotational cutting means  105  being mounted onto the shaft retainer  155  in steps. First the shank  105 S is held in line with the slot  155 S, then lowering the rear end of the shank  105 S so that the rear hook  105 R is engaged with the rear lip  155 L of the shaft retainer  155 . Then the rotational cutter  105  is rotated downwards into the slot  155 S until it comes to rest in the bottom of the slot  155 S. In this position the rotational cutting means  105  can be pulled rearwards. This engages the front hook  105 F with the front lip  155 L and lines up its dowel-pin holes  105 D with the dowel pin holes  155 P in the shaft retainer  155 . Then dowel-pins  155 D are inserted into each dowel-pin hole  155 P. 
     Referring to FIGS. 66-68, a magnet  183  is magnetically isolated from but locked onto the shaft  101  in a position which allows it to pass longitudinally in the area of the transmitter case  129  when the shaft  101  is displaced longitudinally relative to the front housing  111 . The transmitter case  129  is made of non-magnetic material and has a number of magnetic conducting strips  185  isolated from each other. Each strip  185  has an end positioned in a different longitudinal position with its other end positioned in a different radial position around the transmitter cavity  135 . A special transmitter  137 B such as the Digitrac Eclipse produced by Digital Control Inc. has to be used. This transmitter  137 B is built with magnetically sensitive switches  187  that when activated send signals to the receiver to be viewed by the locator and ultimately by the operator 
     Referring to FIG. 69 the female clutch member  153  and the clutch stop  147  of FIGS. 1-68 are replaced in the drilling apparatus by a longer female clutch member  153 L and a corresponding clutch stop  147 B. This makes the housings  111  and  113  of the drilling apparatus of FIGS. 1-68 rotate while the bore is being drilled straight as well as when it is in the shifting mode. The clutch will be disengaged when the drilling apparatus is in the turning mode. 
     Referring to FIGS. 70-72 a third housing  189  may be attached to the rear of the drilling apparatus via the rear ball  121  such that it is rotationally and longitudinally locked to the drilling apparatus. A third housing shaft  101 H is attach to the rear end of the shaft  101 R via a standard collar  191  such that the third housing&#39;s axis is parallel to the shaft  101  and the third housing shaft  101 H is fixedly attached to the shaft  101 . The rear of the third housing  189  is supported on the third housing shaft  101 H via a bearing compartment  189 B. The third housing  189  is designed to hold a larger transmitter  137 L than can be held in the normal transmitter compartment  135 , which is sometimes needed or preferred to produce a bore. One such transmitter is the Subsite produced by Charles Machine Works Incorporated. 
     Referring to FIG. 73 in the third housing  189  a ring collar  191 R can be used, instead of the standard collar  191 , to attach the rear of the shaft  101  and the front of the third housing shaft  101 H. On the inside of the ring collar  191 R is attached a wire  193 . The wire  193  is fed back through the shaft  101 H and ultimately to the drilling rig  103  and onto a receiver. The wire  193  is spliced and made longer upon the addition of each new drill stem. A brush  195  is provided to transmit a signal from a wireline transmitter  137 W that is housed in the third housing  189 . The brush  195  is touching but not solidly attached to the ring collar  191 R such that a constant connection is achieved even when the shaft  101  is rotating or moving longitudinally relative to the third housing  189 . Wireline transmitters are special but not uncommon for longer and/or deeper bores. 
     Operation 
     After the crew foreman has determined the bore path, the crew sets up the drill rig, in this case a Vermeer 24/40 produced by Vermeer Manufacturing Incorporated. With the lead drill stem already on the drill rig, the crew threads the drilling apparatus onto it. The crew will then insert transmitter  137  and calibrate it with the receiver located at the surface. The foreman has chosen to use a cutting means/wear pad ratio that would allow the drilling apparatus to rotate 360-degrees about its own axis when in the shifting position even in a curved hole. He could have chosen a number of different ratios, anywhere from barely turning for sewer bores, to a 1/1 ratio which would give him the tightest turn, but would not allow the drilling apparatus to rotate about its own axis in a curved hole. Although, rotating about it&#39;s own axis in a curved hole is not necessary to its operation, at times it can be handy. Starting at a 15-degree angle with the horizon and the drilling apparatus set to drill straight, the operator of the drill rig begins the bore. 
     Initially, the operator of the system will start out with the followers  177 A and  177 B in the groove positions  145 E as shown in FIG. 36 in order to drill straight. The operator drills straight until the drilling apparatus is about 4′ deep. At this time, he pulls back on the drill stem. This causes reactions in the drilling apparatus, 1) the clutch engages  171  to  153 , 2) the shifting cam followers  177 A and  177 B pull back spinning the shifting cam  145 , and 3) the cam follower lugs  163 S and  163 L slide rearward relative to the guide housings  111  and  113 . 
     The operator can now rotate the drilling apparatus to the desired orientation, in this case 12:00. This places the front wear pad  133  on the bottom of the drilling apparatus and the rear wear pad  151  on the top of it. The operator can now push the drill stem forward. This causes 1) the clutch to disengage  171  from  153 , 2) the shifting cam followers  177 A and  177 B are pulled forward rotating the shifting cam  145 , and 3) the cam follower lugs  163 S and  163 L ride up the main cam  123  which causes the guide housings  111  and  113  to bend or pivot relative to each other and the shaft  101  so that the front wear pad  133  pushes against the bottom of the bore  179 , in the middle of the drilling apparatus, while the rear wear pad  151  pushes on the top of the bore. This reaction forces the cutting means  105 , located on the front of the drilling apparatus upward, changing the direction of travel. When the drilling apparatus has reached its full deflection using the chosen cutting means/wear pad ratio, the turning radius is approximately 110 feet. (Note: choosing other cutting means/wear pad ratios will change the radius of the bore.) 
     The operator can continue turning until he has achieved his desired degree of deviation or until he has to add another drill stem. While adding another drill stem, it is a good time for the crew&#39;s locator to check the position of the drilling apparatus, which includes its inclination, and its X, Y and Z position, with the receiver. For a consistent reading the drilling apparatus needs to be positioned in the same clock position every time. For the best reading, the drilling apparatus needs to be in a 3:00 rotational position, as indicated by the receiver. To do this the operator pulls back on the drill stem approximately 5 inches, then pushes forward approximately 2 inches, and finally pulls back approximately 3 inches. This causes the lugs of followers  177 A and  177 B to be located in the cam groove positions  145 C as depicted in FIG. 44A,  145 E, as depicted in FIG. 44C, and  145 D and as depicted in FIG. 44E respectively. In this position the clutch is engaged and the drill stem can rotate the drilling apparatus until the receiver indicates a 3:00 position. While the drill stem is being changed the locator can take his reading. 
     After adding a new drill stem and calculating his heading the foreman chooses to drill straight. To do this the operator needs to push forward approximately 2 inches and then pull back approximately 2 inches and then forward approximately 4 inches and then back ward approximately 2 inches. This causes the lugs of the cam followers  177 A and  177 B to be located in the cam groove positions  145 A as depicted in FIG. 44G,  145 B, as depicted in FIG.  44 (I),  145 M, as depicted in FIG. 44M, and  145 C, and as depicted in FIG. 44P respectively. In this position he should be able to rotate the drill stem without rotating the drilling apparatus. This indicates that the next time he pushes forward he will be drilling straight. Then pushing forward, he can drill straight for as long as he wants. After drilling for a short distance he notices that the drilling apparatus has drifted slightly off course. Since he is installing steel casing and does not want a major bend in the bore where the pipe will be placed, he decides to use the minor turn feature of the drill head. To do this the operator moves the drill stem back approximately 2 inches, then forward approximately 1 inch, then backward approximately 1 inch, and then pushing forward he can start to drill. This locates the lugs of the followers  177 A and  177 B in the groove positions  145 D as depicted in FIG. 44E,  145 A, as depicted in FIG. 44G,  145 B, as depicted in FIG.  44 (I), and  145 M, and as depicted in FIG. 44M respectively. This will cause the drilling apparatus to change directions, but not as quickly as when using the major turn feature. 
     By oscillating or moving the shaft  101  in and out relative to the drilling apparatus the operator has the choice of a major turning radius, a minor turning radius, or drilling straight. The foreman continues to manipulate the drilling apparatus to achieve his goal of installing steel casing in a directional bore. Furthermore, the foreman has control of the degree of turn that each turning radius gives him by adjusting the diameter of the cutting means in relation to the diameter of the front wear pad and/or the diameter of the rear wear pad before the bore is even started. In this embodiment, while the drilling is being carried out the housings  111  and  113  slide along the bore hole being drilled by the cutting means  105 . 
     FIGS. 74-83 refer to another embodiment of the invention. This embodiment has a single housing  201 . A shaft  203  passes through the housing  201  such that its forward end  203 F passes out of the front of the housing  201  and its rear end  203 R passes out of the rear of the housing  201 . On the shaft&#39;s front end  203 F is mounted a cutting means. The cutting means may be a rotary type  245  as shown in FIGS. 77-79 or a percussion type  247  as shown in FIGS. 74-76. In this embodiment the housing  201  rotates with the shaft  203  while straight drilling is being carried out and the housing  201  does not rotate with the shaft while turn drilling is being carried out. The housing  201  is supported on both ends by bearings  205  and is sealed by seals  207 . The shaft  203  is free to rotate and move longitudinally relative to the housing  201 . The housing supports a front wear pad  209  and a rear wear pad  211 . The two wear pads  209  and  211  are 180 degrees from each other and on opposite ends of the housing  201 . The resulting central axis of the housing  201  is offset from the central axis of the shaft  203  which allows the wear pads  209  and  211  to influence the direction of travel by contacting the bore wall outside of the cutting diameter. The outside of at least one of the wear pads lies outside of the cutting diameter of the cutting means. On the outside of the housing  201  are three spring-loaded friction arms  219  that add resistance to rotation. 
     Inside of the housing  201 , from front to back, is a front housing support  213 , a transmitter housing  215 , a forward stop  217 , a rearward stop  221 , a shifting cam bushing  223  which supports a shifting cam  225  and ties the shifting cam follower  235  rotationally to the guide housing  201 , a female clutch member  227 , and a rear housing support  229 . All of these parts, except the shifting cam  225 , are fixedly attached to the housing  201 . The shifting cam  225  is longitudinally locked to, but is free to rotate relative to, the housing  201 . The cam  225  has grooves formed in its outer surface. 
     On the shaft is a front sleeve  231 , a front thrust bearing  233 , a shifting cam follower body  235  supported on the shaft by bearings  235 B, a rear thrust bearing  237 , a rear spacer  239 , and a male clutch member  241 . The shifting cam follower body  235  has two shifting cam follower arms  235 D and  235 A positioned 180 degrees from each other. The shifting cam follower lugs  235 L on the shifting cam follower arms  235 D and  235 A ride in the grooves  225 A- 225 D of the shifting cam  225 . All of the parts except the shifting cam follower body  235  which holds arms  235 D and  235 A are locked to the shaft  203 . The shifting cam follower  235  is longitudinally locked to the shaft  203  but is free to rotate relative to the shaft  203 . The shifting cam follower  235  is free to move longitudinally with the shaft  203  relative to the housing  201  but is tied rotationally to the guide housing  201 , such that it cannot rotate relative to the guide housing  201 . 
     FIGS. 84-95 show the shifting cam follower  235  being longitudinally displaced relative to the shifting cam  225 . Since the shifting cam follower  235  is locked rotationally to the housing  201  by the shifting cam bushings  223 , the shifting cam  225  is rotated by the lugs  235 L of the shifting cam follower  235  pushing on the walls of the shifting cam grooves  225 A- 225 D. 
     In FIGS. 84-95, the exterior surface of the cam  225  is shown laid flat. The two cam followers  235 A and  235 D are located 180 degrees apart. In FIG. 95, 270 degrees of the cam  225  is shown and in FIG. 95 both cam followers  235 A and  235 D are shown. In FIGS. 84-94, only 180 degrees of the cam  235  is shown and only one cam follower  235 D is shown although it is to be understood that the complete cam  225  and both followers  235 A and  235 D will be employed. In FIGS. 84-95 the horizontal arrows depict the direction of longitudinal travel of the followers  235 A and  235 D and the vertical arrows next to the cam  225  depict the direction of rotation of the cam  225 . In FIGS. 84-95, rearward movement of the followers  235 A and  235 D is to the right and forward movement of the followers  235 A and  235 D is to the left. The lugs  235 L of the followers  235 A and  235 D can be moved between positions displaced fully rearward as shown by follower  235 D in FIG.  87  and to positions fully displaced forward as shown by follower  235 D in FIG.  84  and to intermediate positions. 
     FIG. 84 shows the shifting cam follower arm  235 D in the fully forward or turning position. Shifting cam follower arm  235 A is not pictured in any of the FIGS. 84-94, but is understood to exist. In this position the clutch means is not engaged. Pulling back on the shifting cam follower arm  235 D causes it to contact the shifting cam groove intersection  225 AB (FIG.  85 ). Further rearward displacement causes the shifting cam  225  to be rotated by the shifting cam follower lugs  235 L pushing on the wall of the shifting cam groove  225 B (FIG.  86 ). Rearward displacement is stopped when the shifting cam follower body  235  contacts the rearward stop  221  (FIG.  87  and FIG.  82 ). In this position the clutch means is engaged. Forward displacement of the shifting cam follower arm  235 D causes the shifting cam follower lug  235 L to contact the shifting cam groove intersection  225 BC (FIG.  88 ). Further forward displacement of the shifting cam follower arm  235 D causes the shifting cam follower lug  235 L to push on the wall of the shifting cam groove  225 C (FIG.  89 ). This causes the shifting cam  225  to rotate. Forward displacement of the shifting cam follower arm  235 D is halted when the shifting cam follower lug  235 L contacts the end of the shifting cam groove  225 C (FIG.  90 ). This is the straight drilling position. In this position the clutch means is still engaged and the whole drilling apparatus, including the housing  201 , is being rotated as the hole is drilled (FIG.  80 ). Rearward displacement of the shifting cam follower arm  235 D causes the shifting cam follower lug  235 L to contact the shifting cam groove intersection  225 CD (FIG.  91 ). Further rearward displacement of the shifting cam follower arm  235 D causes the shifting cam follower lug  235 L to push on the wall of the shifting cam groove  225 D (FIG.  92 ). This causes the shifting cam  225  to rotate relative to the housing  201 . Again the rearward displacement of the shifting cam follower arm  235  relative to the shifting cam  225  is halted when the shifting cam body  235 C contacts the rearward stop  221  (FIG.  93  and FIG.  82 ). In this position the housing  201  can be rotated to a desired clock position in preparation for drilling a curved hole in the chosen direction. Forward displacement of the shifting cam follower arm  235 D causes the shifting cam follower lug  235 L to contact the shifting cam groove intersection  225 DA. Further forward displacement of the shifting cam follower arms  235 D and  235 A causes the shifting cam follower lugs to push on the walls of the shifting cam grooves  225 A (FIG.  95 ). This causes the shifting cam  225  to rotate. Forward displacement is halted when the shifting cam body  235 C contacts the forward stop  217  (FIG.  81  and FIG.  84 ). In this position the clutch means is disengaged and the housing  201  is held from rotating by friction on the walls of the bore. While the drill stem is rotating and thrusting forward the cutting means  245  or  247 , the drilling apparatus is drilling a curved hole. Further manipulations of the drill stems allow the operator to control the direction of travel. 
     When using a rotary type cutting means  245  with this embodiment, a hole-opener  243  is to be employed directly behind housing  201 . The hole-opener  243  is fixedly attached to the shaft  203  and is designed to enlarge the bore enough to allow the entire drilling apparatus to rotate around its own axis, even in a curved hole. If the drilling apparatus is not positioned in a sufficiently large void to allow the drilling apparatus to be rotated about its own axis without hindrance from the bore walls, undue strain and stress will be placed on the drilling apparatus. Furthermore the complete rotation of the drilling apparatus may not be possible in a non-enlarged bore, thus hindering the ability to control the path of the bore. 
     To use this embodiment with a percussion type cutting means  247 , the drilling crew would first thread the drilling apparatus onto the lead drill stem. Then they would mount the percussion head  247  on the front of the drilling apparatus. Next, the transmitter  137  would be inserted under the front wear pad  209 . With these things done the bore is ready to begin. Starting with the drilling apparatus in the straight drilling mode and the percussion bit  247  pressed up against the ground, the fluid medium usually either compressed air or water is switched on. This causes the bit  247  to vibrate in and out pulverizing even the hardest rock. As the drilling apparatus is advanced, it is rotated. This makes the bit  247  move in a circular motion with the center of the bore off center from the center of the bit  247 . The resultant bore diameter is larger than the cutting bit diameter. As long as the apparatus is moved forward and rotated with the percussion cutting means  247  activated it will drill relatively straight. When the operator wants to change direction, he pulls back on the drill stem. This causes the shifting cam follower  235  to rotate the shifting cam  225 . The rearward displacement ceases when the shifting cam follower  235  encounters the rearward stop  221 . The drill stem can now rotate the drilling apparatus to the desired rotational position. Once in the desired position, the drill stem can be pushed forward causing the shaft  203  to be forwardly displaced relative to the housing  201 . This disengages the clutch means  241  from  227  and causes the shifting cam follower  235  to rotate the shifting cam  225 . The forward displacement is halted when the shifting cam follower  235  hits the forward stop  217 . The bit  247  is pressed against the earth and the fluid medium is switched on. This causes the bit  247  to vibrate in and out pulverizing the rock. The drill stem can be rotated allowing the bit  247  to impact various spots on the face of the rock being drilled. The bit  247  is rotated about its own center. While turning, the housing  201  is held from rotating by the friction arms  219  that are contacting the wall of the bore. Since the housings wear pads  209  and  211  lay outside of the cutting radius of the percussion means  247 , they push on the wall of the bore which in turn pushes on the drilling apparatus moving the cutting means  247  in the opposite direction. The bore can be drilled in the turning mode as far as needed. To drill straight again the drill stem is pulled back. This causes the shifting cam follower  235  to rotate the shifting cam  225  and engages the clutch means  241  to  227 . The drill stem is then pushed forward causing the shaft  203  to be displaced relative to the housing  201  until the grooves  225 C (FIG. 90) in the shifting cam  225  stop the shifting cam follower  235 . In this position the clutch means  241  to  227  is still engaged such that when the drill stem rotates the shaft  203 , the entire drilling apparatus, including the housing  201 , is rotated. Since the curved hole that the drilling apparatus is now in, is too small to allow the rotation of the drilling apparatus about its axis at first, the percussion means  247  is activated and slowly rotated along with the housing  201  which enlarges the bore diameter. After one revolution, normal drilling can be resumed. The operator can choose between straight and curved drilling at any time. The operator knows that he is drilling straight when he is drilling and the transmitter is showing that the drilling apparatus is rotating. Likewise he knows when he is drilling a curved hole when he is drilling and the transmitter is showing that the drilling apparatus is not rotating. 
     To use this embodiment with a rotary type cutting means  245 . The drilling crew would first thread the drilling apparatus onto the lead drill stem. Then the crew would mount the rotary drill bit  245  on the front of the drilling apparatus. Next, the transmitter  137  would be inserted under the front wear pad  209 . Starting with the drill head in the straight drilling mode, the drill stem is rotated and then thrust forward. This makes the drilling apparatus, including the housing  201 , as well as the rotary drill bit  245  to do the same, which drills a straight hole. 
     When the operator wants to turn, he pulls back on the drill stem, which pulls back on the shaft  203  causing it to be displaced relative to the housing  201 . At the same time the shifting cam follower  235  rotates the shifting cam  225 . The drill stem can be rotated which rotates the shaft  203 , which in turn rotates the drilling apparatus until the desired rotational direction is reached. Then pushing forward the shifting cam follower  235  rotates the shifting cam  225  and the clutch means  241  is disengaged from  227 . The forward displacement is stopped when the shifting cam follower  235  hits the forward stop  217 . With the housing held rotationally in place by the friction arms  219 , the drill stem, the shaft  203 , and rotary drill bit  245  are rotated and thrust forward cutting the hole. Since at least one wear pad  209  and/or  211  lies outside of the cutting diameter of the rotary bit  245 , the protruding wear pad  209  and/or  211  contacts the wall causing the drilling apparatus to be deflected in the opposite direction. While the curved hole is being drilled a hole opener  243  on the rear of the drilling apparatus is enlarging the hole, which is also true when a straight hole is being drilled, but to a lesser extent, because a straight hole is bigger than a curved hole. The curved hole can be cut until the operator chooses to drill straight. When he does desire to drill straight, he pulls back on the drill stem for at least five feet, which positions the entire drilling apparatus in the enlarged hole. While pulling back the shaft  203  and shifting cam follower  235  are displaced relative to the housing  201  and the shifting cam  225 . This causes the shifting cam follower  235  to rotate the shifting cam  225  and the clutch means  241  and  227  to engage. The drill stem is then pushed forward which causes the shaft  203 , the shifting cam follower  235  and the male clutch means  241  to be displaced relative to the housing  201 , the shifting cam  225  and the female clutch member  227 . The shifting cam follower  235  hitting the grooves  225 C (FIG. 90) in the shifting cam  225  stops the forward displacement. In this position the clutch members  241  to  227  are still engaged which causes the housing  201  to rotate and the bore to be drilled straight. The drill stem is now thrust forward and rotated which causes the entire drilling apparatus to be rotated and thrust forward. The resulting bore is relatively straight and of a larger diameter than the diameter of the rotary drill bit  245 . The operator knows that he is drilling straight, if while he is drilling the transmitter is indicating that the housing  201  is rotating and conversely he is turning if the transmitter indicates that the housing  201  is not rotating. 
     After the bore has reach its destination the drilling crew may wish to enlarge the hole using a hole-opener. If so, they would use a system that attaches rotational cutting means to a hole-opener in a manner similar to the way the rotational cutting means  105  were attached to the shaft retainer  155 . (NOTE: the rotational cutting means may be one or more of any style on the market, including roller cones and bullet teeth, with the only change being the mounting shank made special for this application.) 
     Referring to FIGS. 96-106 the rotational cutting means  251  are individual wings positioned on the hole-opener body  249  in radial positions to form a hole-opener  255 . Four slots  249 S are cut lengthwise into the hole-opener body  249 . On the front and rear of the hole-opener body  249  are cut eight slots  249 LS perpendicular to the slots  249 S such that they leave behind a lip  249 L corresponding to the front and rear of each slot  249 S. Two dowel-pin holes  249 P are drilled perpendicular to each slot  249 S such that they are in a position to allow dowel-pins  253  to lock the rotational cutting means  251  in place. The dowel-pin holes  249 P are drilled so that the dowel-pins  253  can be inserted and extricated from the direction of rotation such that upon rotation in the proper and common direction, the dowel-pins  253  will not be pushed out of the dowel-pin holes  249 P. Smaller diameter hole portions are formed in the body  249  on the other side of each slot to allow the dowel-pins  253  to be pressed out. On the front of the hole-opener body  249  are four openings  249 H that allow water or other medium to escape from inside the hole-opener body  249 . The rotational cutting means  251  have a section behind the actual cutting area  251 C that is called the shank  251 S. The shank  251 S is of a shape that will fit into one of the slots  249 S with little clearance. On the front is a front hook  251 F. On the rear is a rear hook  251 R. Two dowel-pin holes  251 P are drilled in the middle of the shank  251 S. FIGS. 99-104 show the rotational cutting means  251  being mounted onto the hole-opener body  249  in steps. First the shank  251 S is held in line with the slot  249 S, then lowering the rear end of the shank  251 S so that the rear hook  251 R is engaged with the rear lip  249 L of the hole-opener  249 . Then the rotational cutting means  251  is rotated downwards into the slot  249 S until it comes to rest in the bottom of the slot  249 S. In this position the rotational cutting means  251  can be pulled rearwards. This engages the front hook  251 F with the front lip  249 L and lines up its dowel-pin holes  251 P with the dowel-pin holes  249 P in the hole-opener body  249 . Then dowel-pins  253  are inserted into each dowel-pin hole  249 P. With the rotational cutting means  251  attached to the hole-opener body  249  the hole-opener  255  is ready for use. 
     To use this hole-opener  255  the drilling crew would attach the hole-opener  249  body to the drill-string  175 D. Then the drill rig operator would rotate the drill string  175 D and begin to pull the hole-opener  255  through the previously bored hole  257  leaving behind an enlarged hole  259 . (NOTE: the hole-opener  255  can be mounted and used to be pulled through the previously bored hole or it can be mounted and used to be pushed through the previously bored hole.) 
     In hole-opener  255 , four slots  249 S were used and in the shaft retainer  155  three slots  155 S were used. If desired as few as only one slot  249 S maybe used in the hole-opener  255  and also only one slot  155 S may be used in the shaft retainer  155 . If only one slot  249 S is used in the hole-opener  255  or if only one slot  155 S is used in the shaft retainer  155  the single rotational cutting means  105  or  251  would cut the entire diameter when rotated in a complete revolution. 
     In the single slot shaft retainer  155  a different version of the rotational cutting means  105  may be more desirable. In this version the rotational cutting means  261  would extend across the desired diameter of the hole as in FIGS. 107 and 108. In FIG. 107 cutting edges are shown at  217  and  273  and  155 A is the axis of rotation. In FIG. 108, a cutting edge is shown at  271  and member  275  is a roller cutting cone.

Technology Classification (CPC): 4