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BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is directed to systems for moving tubulars and pipe stands in a derrick; to systems for transferring a tubular or a stand of pipe between a fingerboard area and a well center; and to methods of the use of such systems. 
     2. Description of Related Art 
     A wide variety of drilling systems, apparatus, and methods are known, including, but not limited to, the disclosures in U.S. Pat. Nos. 6,944,547; 6,918,453; 6,802,378; 6,050,348; 5,465,799; 4,995,465; 4,854,397; 4,850,439; and 3,658,138. A wide variety of tubular handling and tubular transfer systems for wellbore operations are known; for example, and not by way of limitation, those disclosed in U.S. Pat. Nos. 7,293,607; 7,137,454; 7,083,007; 6,976,540; 6,821,071; 6,779,614; 5,988,299; 5,451,129; 4,862,973; 4,765,401; 4,725,179; 4,462,733; 4,345,864; 4,274,778; 4,269,554; 4,128,135; 4,044,895; 4,042,123; 4,013,178; and in U.S. Patent Application 2006/0081379. 
     In certain well drilling methods, a string of drill pipe having a drill bit mounted on the lower end thereof is suspended from a traveling block in a drilling rig mast. The drill string is suspended from the traveling block by a swivel which enables rotational force to be applied to the drill string, typically by a rotary table at the drilling rig floor, or a power swivel or top drive in the derrick to advance the depth of the drilled bore. As the depth of the bore increases, additional lengths of drill pipe are added to the drill string at the surface. 
     Often, for various reasons, the drill string is pulled from the bore, e.g., in order to change the drill bit or to run testing or other equipment into the bore on the end of the drill string. When pulling drill pipe from the bore, the traveling block is raised until a stand (multiple connected pieces) of pipe extends above the drilling rig floor. In certain cases, a stand comprises two or three pieces of pipe, e.g. three pieces totaling approximately 90 feet in length. Next, slips are placed between the pipe and the drilling rig floor in order to suspend the drill string in the well bore from a point beneath the pipe stand which extends above the drilling rig floor. The connection between the pipe stand and the remainder of the drill string is unthreaded and the lower end of the stand is placed on a support pad, sometimes referred to as a setback, on the drilling rig floor. Next, a man positioned in the upper portion of the rig disconnects the upper end of the stand from the traveling block and places the upper end of the stand between a set of racking fingers on a fingerboard which support the stand in a substantially vertical position. The traveling block is then lowered to pick up the drill string and the process is repeated until all of the pipe, e.g. in three piece stands, is supported at the lower ends thereof on the setback with the upper ends being constrained between pairs of racking fingers on the fingerboard. When running a new drill bit or a tool into the well bore, this process is reversed. This process is repeated until the drill string is removed or, in the reverse process, when the drill bit reaches a desired depth in the well bore. 
     A variety of difficulties and dangers can be associated with procedures for running a drill string into or out of a well bore to personnel involved in these procedures, e.g., personnel working on a platform above a drilling rig floor. This job can entail reaching from the platform to the center line of the well in order to connect the upper end of a pipe stand to the traveling block (and to disconnect the same therefrom) and can require moving the upper end of each pipe stand between the racking fingers and the center line of the well. 
     Various efforts have been made to automate one aspect or another of the procedure for running drill pipe into and out of the well bore. Some of these procedures incorporate the use of mechanical arms mounted on the drilling rig mast adjacent the racking fingers for moving the upper ends of the pipe stands between the well center line and the racking fingers. Some include lower arms or dollies for simultaneously gripping the lower end of the stand in order to move it between the well center line and the setback. Some of the known devices move the stands in response to control signals generated by a computer. Several of the known devices are cumbersome in their design and, thus, in their operation and are expensive to build. Some known apparatus have a single arm for manipulating pipe at the upper end of a pipe stand. 
     U.S. Pat. No. 4,725,179 describes an automated racking apparatus for use to facilitate coupling and uncoupling substantially vertical lengths of pipe by moving the pipe between a coupled position and a racking assembly. An arm assembly includes a gripping head mounted thereon for grasping a pipe. Apparatus are provided for moving the arm assembly. The lower end of a pipe received in the racking assembly is supported by a support assembly which includes sensor apparatus the location of the lower end of each pipe on the support assembly. Control apparatus connected to the sensor apparatus and to the moving apparatus is provided for moving the arm assembly to a preselected position dependent upon the position of the lower end of a pipe which is set on or removed from the support assembly. In one aspect, the arm assembly includes a first arm and a second arm which are extendable and retractable along axes oriented at ninety degrees to one another. In one aspect, U.S. Pat. No. 4,725,179 describes an automated pipe racking apparatus for use to facilitate threading and unthreading substantially vertical lengths of pipe on a drilling rig by moving the pipe between the well bore center line and a racking assembly. An arm having a gripping head mounted thereon is extendable and retractable relative to a carriage mounted on the drilling rig working board. When storing pipe, the lower end of each pipe is set on a support assembly which includes a plurality of switches which signal the position of each pipe thereon. The arm and carriage are moved under control of a computer to an appropriate slot for storing the upper end of the pipe stand. When running pipe into the well bore, the arm and carriage move the upper end of the pipe to the center line of the well and when the traveling block of the drilling rig picks up the pipe, a signal generated by the switch beneath the pipe causes the carriage and arm to move to the location for unracking the next stand of pipe; which in one particular aspect, includes an arm assembly having a gripping head mounted thereon for grasping a pipe, apparatus for moving the arm assembly, a support assembly for supporting the lower end of a pipe received in the racking assembly, apparatus for sensing the location of the lower end of each pipe on the support assembly; and control apparatus operatively connected to the sensing apparatus and to the moving apparatus for moving the arm assembly to a preselected position dependent upon the position of the lower end of a pipe which is set on or removed from the support assembly. 
     U.S. Pat. No. 6,821,071 describes an automated pipe racking apparatus for a drilling rig having an elevator suspended over a well bore. An arm support member is rotatable about an axis parallel to the well bore. A gripper arm extends from the arm support member along an axis normal to the axis of rotation of the arm support member. A gripper head assembly extends from the gripper arm, the gripper head assembly having a pair of opposed, arcuate gripper fingers, each said finger rotatable by a motor. In one aspect, an automated pipe racking process is proposed for a drilling rig with an elevator suspended over a well bore, which process includes: lifting a pipe stand having at least one pipe section with the elevator; moving a lower end of the pipe stand over a base pad; setting the lower end of the pipe stand down onto a base pad; capturing the pipe stand with a gripper head assembly having a pair of rotating arcuate fingers; releasing the pipe stand from the elevator; and moving an upper end of the pipe stand with the gripper head assembly to a chosen location. 
     U.S. Pat. No. 7,083,007 describes a fingerboard having at least one fingerboard row for storing a plurality of threaded tubulars with a plurality of latches connected to the at least one fingerboard row for lockingly retaining at least one threaded tubular, wherein each of the plurality of latches is movable between a locked position and an unlocked position. A row controller is connected to each of the latches for individually and sequentially moving the latches between the locked and unlocked positions, wherein the row controller is manually operable from a location remote from the latches such that the latches are manually and remotely controlled. In one aspect, a fingerboard is disclosed that includes: at least one fingerboard row for storing a plurality of threaded tubulars; a plurality of latches connected to the at least one fingerboard row for lockingly retaining at least one threaded tubular, wherein each of the plurality of latches is movable between a locked position and an unlocked position; and a row controller connected to each of the latches for individually and sequentially moving the latches between the locked and unlocked positions, wherein the row controller is manually operable from a location remote from the latches such that the latches are manually and remotely controlled. In one aspect, a method of storing a plurality of threaded tubulars in a fingerboard is proposed that includes: providing a fingerboard row for storing the plurality of threaded tubulars; providing a casing having a plurality of exhaust ports, wherein each of the plurality of exhaust ports corresponds to at least one of the plurality of threaded tubulars; providing a piston having an elongated rod that is moveable relative to the casing; connecting a plurality of latches to the fingerboard row, wherein each of the plurality of latches is connected to a corresponding one of the plurality of exhaust ports and each latch is biased to a closed position and moveable between the closed position and an opened position; connecting an air source to the casing; moving the elongated rod to a fully extended position such that each exhaust port is uncovered by the elongated rod and air from the air source enters each uncovered exhaust port and forces each of the latches into a unlocked position; adding successive ones of the plurality of threaded tubulars to a position within the fingerboard row; and moving the elongated rod to one of a plurality of retracted positions to cover the corresponding exhaust port of each added threaded tubular causing each latch to be biased from the unlocked position to the locked position to lock each added threaded tubular to the fingerboard row. 
     U.S. Pat. No. 4,042,123 describes an hydraulically powered pipe handling system, a general purpose digital computer is used to control the operation of hydraulically powered racker arms as well as the various auxiliary functions involved in vertical pipe racking operations. The manual pipe-racking system (that is, that which is hydraulically powered and under the control of one or more operators) is retained, the computer controlled mode of operation being an alternative system present in the overall design. There is provided to the operator, while the system is in its automatic mode of operation, visual indication of length of drill string, depth of hole, depth of drill bit and composition of the drill string, including number and type of pipe lengths making up the drill string. In one aspect, a drill pipe handling system for the automated handling of drill pipe lengths, in a well being drilled or otherwise serviced, is described including: rack apparatus for receiving pipe stands and supporting the pipe stands in spaced apart vertical rows adjacent the side of a derrick, the rack apparatus including a series of parallel rows for receiving the pipe stands and fingers selectively actuable for forming rectangular openings along the parallel rows for locking the pipe stands in place; sensor apparatus for sensing the individual actuation of the fingers; racker apparatus for successively moving the drill pipe stands between a position adjacent the center of the derrick and the rack apparatus; a racker arm extending horizontally from the racker apparatus, the racker arm having a gripper at the outer end thereof for engaging the drill pipe stands; computer control apparatus for controlling the rack apparatus, the fingers, the racker apparatus, and the racker arm; the computer control apparatus including, a programmable general purpose digital computer; a computer program for providing sequential instructions to the digital computer; input-output apparatus for monitoring and controlling the digital computer; the input-output apparatus including, display apparatus for providing visual indication of the status of the computer program and for permitting data or instructions to be input to the digital computer; and a driller&#39;s console for permitting control of the drill pipe handling system by inputting instructions to the digital computer, the console including a selector for selecting automated or manual operations of the handling system, and controls and indicator apparatus for starting or stopping the automated function of the handling system and for providing visual indication of the operating status of the handling system. 
     Due to the narrow width of the fingers in some fingerboards, some prior known gripper heads have a narrow side or part for reaching in between a target stand and a stand in a next row, and a thick side or part which can take up the space vacated by the stand in the previous row. This arrangement requires that the head, or part of it, be reversed when going from one setback area to the other. Also, it does not reach down a row with stands on either side. Certain conventional systems have a gripping head, or gripper with two projecting parts, e.g., but not limited to, as in U.S. Pat. Nos. 4,725,179 and 4,044,985, in which one part is sized (often generally straight, usually relatively narrow) to enter between pipes or tubulars on adjacent rows of a fingerboard and a second part is sized and located to encompass a portion of a pipe or tubular to be moved. In certain aspects, the first part is relatively straight and the second part is curved. To go between pipe or tubulars on one side of the fingerboard, the first part is inserted between two pipes. For use on an opposite side of the fingerboard, the gripping head is turned over so that the first part can go between pipes in adjacent rows. This is necessary because the second curved part of the gripping head cannot fit between two adjacent pipes, each in an adjacent row. 
     SUMMARY OF THE INVENTION 
     An aspect of the invention provides systems for transferring pipe (including tubulars such as casing, tubing, drill pipe, etc.) or stands of pipe from one location to another in a wellbore derrick, e.g. from a fingerboard to a well center. 
     An aspect of the invention provides a pipe handler for handling pipe in a fingerboard, the fingerboard having a plurality of spaced-apart fingers for supporting a plurality of tubulars, e.g. pieces of pipe, the pipe handler including: a pipe handling head having a head width; a distance comprising a second width, the second width including the distance between two fingers of the finger board and twice the width of one finger; and the head width less than the second width to facilitate movement of the pipe handling head along a row between the two fingers. 
     An aspect of the invention provides a pipe handler for handling pipe in a fingerboard, the fingerboard having a plurality of spaced-apart fingers for supporting a plurality of tubulars, e.g. pieces of pipe, the pipe handler including: a pipe handling head, extension apparatus for moving the pipe handling head, carriage apparatus, the extension apparatus connected to the pipe handling head and to carriage apparatus, track structure, the carriage apparatus movable on the track structure so that the pipe handling head can access pipe on the fingerboard, at least one movable arm movable with respect to a pipe on the fingerboard to facilitate engagement of the pipe by the pipe handling head, and at least one flipper (or multiple flippers) movably connected to the at least one movable arm (or arms), the at least one flipper (or flippers) projecting inwardly of the at least one movable arm (or arms), the at least one flipper (or flippers) constantly biased inwardly to assist in maintaining pipe in position in the pipe handling head. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more particular description of embodiments of the invention briefly summarized above may be had by references to the embodiments which are shown in the drawings which form a part of this specification. 
         FIG. 1A  is a perspective view of a pipe handling system. 
         FIG. 1B  is a top view of the system of  FIG. 1A . 
         FIG. 1C  is a perspective view of the system of  FIG. 1A . 
         FIG. 1D  is a top view of the system of  FIG. 1A . 
         FIG. 1E  is a perspective view of the system of  FIG. 1A . 
         FIG. 1F  is a top view of the system of  FIG. 1A . 
         FIG. 2A  is a perspective view of part of the system of  FIG. 1A . 
         FIG. 2B  is a front view of part of the system as shown in  FIG. 2A . 
         FIG. 3  is a perspective view of a pipe handler according to the present invention of the system of  FIG. 1A . 
         FIG. 4  is a side view of the pipe handler of  FIG. 3 . 
         FIG. 5  is a side view of the pipe handler of  FIG. 3  with the pipe handler extended. 
         FIG. 6  is a top view of the pipe handler of  FIG. 5 . 
         FIG. 7A  is a top perspective view of a pipe handling head of the pipe handler of  FIG. 5 . 
         FIG. 7B  is a partial perspective view of the pipe handling head of  FIG. 7A . 
         FIG. 7C  is an exploded view of part of the pipe handling head of  FIG. 7A . 
         FIG. 7D  is a top view of the pipe handling head of  FIG. 7A . 
         FIG. 7E  is a side view of inner mechanisms of the part of  FIG. 7A . 
         FIG. 8A  is a top view of a pipe handling head according to the present invention. 
         FIG. 8B  is a top view of the pipe handling head of  FIG. 8A . 
         FIG. 9A  is a top view of a pipe handling head according to the present invention. 
         FIG. 9B  is a top view of the pipe handling head of  FIG. 9A . 
         FIG. 10A  is a top view of a pipe handling head according to the present invention. 
         FIG. 10B  is a top view of the pipe handling head of  FIG. 10A . 
         FIG. 11A  is a perspective view of a pipe handling system according to the present invention. 
         FIG. 11B  is a perspective view of part of the system of  FIG. 11A . 
         FIG. 11C  is a side view of the part shown in  FIG. 11B . 
         FIG. 11D  is a partial perspective view of parts of the carriage of the pipe handler of the system of  FIG. 11A . 
         FIG. 11E  is a perspective view of the parts as shown in  FIG. 11D . 
         FIG. 11F  is an enlargement of part of the system as shown in  FIG. 11D . 
         FIG. 12A  is a top view of part of a carriage of the pipe handler of  FIG. 11A . 
         FIG. 12B  is an enlarged view of part of the carriage as shown in  FIG. 12A . 
         FIG. 12C  is a perspective view of part of the pipe handler of  FIG. 12A . 
         FIG. 12D  is an enlarged view of part of the carriage as shown in  FIG. 12C . 
         FIG. 12E  is an end view of part of the carriage of the pipe handler of  FIG. 12A . 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to  FIG. 1 , a system  10  according to the present invention has a track  20  mounted between rows  12  of fingers  14  of a fingerboard  16 . A pipe handler  50  according to the present invention is movably mounted on the track  20 . The pipe handler  50  has a carriage  52  with rotatable rollers  54  which roll in channels  22  of the track  20 . 
     As discussed in detail below, a selectively locking mechanism  70  of the pipe handler  50  (or mechanisms  70 ) engages a lock rim  24  (or rims) of the track  20 . The pipe handler  50  has a pipe handling head  60 . 
     As shown in  FIGS. 1A ,  1 C, and  1 E, the pipe handler  50  is movable on the track  20  so that the pipe handling head  60  can access any pipe or stand of pipes supported by the fingerboard  16 . As shown in  FIGS. 1D ,  1 E,  1 F,  2 A,  5  and  6 , the pipe handler  50  is extendable so that the pipe handling head  60  can move pipe or a stand of pipe to a desired location. 
     As shown in  FIG. 1A , the track  20  is located below a level of the fingers  14 . As described below (see  FIGS. 12A-12C ) the pipe handler may, according to the present invention, be located below the fingerboard. 
     Optionally, the track  20  has a storage section  26  projecting out from the fingerboard  16 . As shown e.g. in  FIGS. 1A and 1B , the pipe handler  50  may be stored in the storage section  26 . In one aspect, the pipe handler  50  is installed on the track  20  by lowering it over the storage section  26  and then into the storage section  26 . The channels  22  do not extend into the storage section  26  and the rollers  54  rest on bottom surfaces  28  of the storage section  26 . 
     As shown in  FIG. 1F , in certain particular aspects, the pipe handling head  60  has a width “a” less than a width “b” (“b” is the width between two fingers  14  plus two finger widths). In such an embodiment, the pipe handling head  60  can be moved down any row  12  of the fingerboard  16  without contacting a pipe or stand in an adjacent row. 
     In one aspect, the lock rim  24  has wedge members  25  which meet at points  27  and the locking mechanism  70  locks the pipe handler  50  in position so that the pipe handling head  60 , e.g. as shown in  FIG. 1F , is positioned in the center of a row  12  of the fingerboard  16 . 
     As shown, e.g., in  FIGS. 2A and 2B , the pipe handler  50  has a rotatable base  56  on the base  52 . A rack-and-pinion apparatus  51  rotates the rotatable base  56  and all it supports through a full 180 degrees. 
     An extension mechanism  80  is pivotally mounted to a main support  58  on the base  56 . The pipe handling head  60  is pivotally mounted to a distal end  82  of the extension mechanism  80 . A powered cylinder apparatus  84  powers the selective extension and retraction of the extension mechanism  80 . 
     A control system CS, shown schematically,  FIGS. 2A and 3A , controls the pipe handler  50 , the apparatus  51 , the pipe handling head  60 , the locking mechanism  70 , and the apparatus  84 . In one aspect the control system CS is located at fingerboard level and/or at drill floor level (e.g., at a driller&#39;s console) and, in one aspect, includes a camera or cameras to provide view or views of the system during operation. In one aspect a control system at fingerboard level is a manual control system. In other aspects, the control system is an electronic and/or computerized control system. 
     The locking mechanism  70  has a powered piston apparatus  73  with an extendable rod  72 . With the rod  72  under pressure so that it is constantly forced outward (toward the lock rim  24 ), as the pipe handler  50  moves on the track  20 , the rod  72  is thrust against the wedge members  25 . The wedge shape facilitates movement of the end of the rod  72  into a point  27 . With the wedge members  25  appropriately located, they line up with the fingers  14  of the fingerboard  16  (e.g., so that the desired positioning of the pipe handling head  60 , discussed above, can be achieved). 
     As shown in  FIGS. 1A ,  1 B,  1 C and  4 , the extension mechanism  80  is in a retracted configuration. As shown in  FIGS. 1D ,  1 E,  1 F,  2 A,  3 ,  5  and  6 , the extension mechanism  80  is in an extended position. 
       FIGS. 7A-7E  shows a pipe handling head  60  according to the present invention with a body  62 , movable arms  64 , and movable flippers  66 . Links  68  movably connect the arms  64  to the body  62  (with pins  122  through blocks  124 ). Links  69  pivotally connect the arms  64  to a clevis  90 . A power cylinder apparatus  100 , connected to the body  62  and to the clevis  90 , moves the arms  64  toward and away from each other, resulting in the movement of the arms  64  toward and away from each other. Adjustability of the arms and their spacing via this structure allows one head  60  to handle different pipe sizes. 
     Springs  112  (shown in dotted line in  FIGS. 2A ,  2 B) within powered cylinder apparatuses  102  provide a constant pressure on the flippers  66  biasing the flippers  66  outwardly from the head  60 . The control system controls the apparatuses  102  to selectively and, as desired, move the flippers  66  e.g. to pull them in for release of a pipe. The force of a pipe entering a throat  63  between the arms  64  against the flippers  66 , when the force is sufficient (the force of the head moved against the pipe), moves the flippers  66  inwardly against the force of the springs, (and at this time, force springs in the powered cylinders also forcing the flippers out) allowing the pipe to pass into the throat  63 . Thus, no operator input is required to capture the pipe or stand in the throat  63 . Once the pipe has passed the flippers  66  and is between the arms  64 , the force applied by the apparatuses  102  moves the flippers  66  back to their initial position. Once the flippers  66  return to their original positions, they will remain there, even in the event of the loss of hydraulic power. To release the flippers, air pressure is applied to the opposite side of the piston, overcoming the spring force. 
     With the flippers  66  located on the arms  64  as shown in  FIG. 7A , pipe or stands adjacent to a pipe or stand being captured will not contact or damage the flippers  66 . 
     Each flipper  66  has one end pivotally connected to an arm  64  with a pin  104 . A link  106  is pivotally connected at one end to the flipper  66  with a pin  116 , and at the other end, with a pin  108 , to the apparatus  102 . The pins  108  extend into slots  114  in the arms  64  which permit movement of the flippers  66  toward the arms  64  so that a pipe larger in diameter than the initial distance between the flippers  66  can move the flippers  66  and pass between them. Appropriate washers W; nuts, N; and bushings, B are used with the various connections. 
     A bracket  130  connected to the body  62  has a tube  132  connected thereto which provides a connection for connecting the pipe handling head  60  to the pipe handler  50 . An end plate  134  is removable secured over an end of the body  62 . 
     The arms  64  are sized and configured so that the head does not require reversal when going between setbacks and can reach down a row with stands on either side of a fingerboard. 
     The flippers  66  are compliant (they move out of the way when pushed against a pipe) in the direction of arm extension, so that the force of the arms  64  is reacted by the body  62  (and the flippers move back once a pipe has passed). 
       FIG. 11A  shows a system  300  according to the present invention like the system according to the present invention shown in  FIG. 1A ; but in the system  300  a pipe handler  350  according to the present invention (like the pipe handler  50  in many respects) is disposed beneath a fingerboard  316  (like the fingerboard  16 ). The pipe handler  350  has a carriage  352  with rollers  354  that move in channels  322 . Selective locking mechanisms  370  engage a lock structure  324  on the channels  322 . The pipe handler  350  with a pipe handling head  360  (like the pipe handling head  60 ) is movable on the channels  322  so that the handling head  360  can access tubulars as does the handling head  60  (as described above). The pipe handling head  360  has a rotatable base, extension mechanism, powered cylinder apparatus, and control system(s) like those of the pipe handler  50 . 
     The selective locking mechanisms  370  act (as does the mechanism  70  described above) to secure the carriage  352  in place so that the pipe handler  350  is located to conveniently access pipe in rows of the fingerboard  316 . Although shown only partially (e.g. as in  FIG. 11F ) the lock structure  324  has a plurality of spaced-apart wedges  325  along the length of each channel  322 . It is within the scope of the present invention to use only one locking structure  324  and only one corresponding mechanism  370 . 
     As the carriage  325  moves on the channels  322 , when the carriage  352  approaches a desired location, e.g. the system is aligned with pipe in a selected row, a powered assembly  326  (e.g. a powered piston assembly) is actuated by the control system or manually which forces a roller  327  on a movable arm  321  down into the bottom of a valley  329  between two selected wedges  325 . 
     Optionally, the system  300  (or any system according to the present invention, e.g., the system  10 ) has a stop system  400  which limits slewing of the pipe handler  350  and correctly positions it in line with a well center of a rig on which the pipe handler is used, the stop system  400  also, optionally, has shock absorbing structure for controlled deceleration of the pipe handler  350  as it approaches a desired final position. 
     The system  400  (see  FIG. 12A ) has a base  403  secured to the carriage  352 . Two pins  401 ,  402  are movably mounted to the base with mountings  401   m ,  402   m  respectively. A powered cylinder apparatus  401   c , controlled by a control system (e.g. a controlled system CS) connected to the pin  401  via a link  401   l , selectively moves the pin  401 . A powered cylinder apparatus  402   c , controlled by a control system (e.g. a controlled system CS) connected to the pin  402  via a link  402   l , selectively moves the pin  402 . 
     The pins  401 ,  402  are movable with respect to the carriage  352  to abut a movable plunger  405  of a shock absorber  406  (pin  401 ) or a plunger  407  of a shock absorber  408  (pin  402 ). The shock absorbers  406 ,  408  are secured to a base  382  of the pipe handler  350  with mounts  406   m ,  408   m , respectively. 
     The shock absorbers  406 ,  408  are positioned so that when the pine  410  is extended, it abuts the shock absorber  406  and the pipe handler  350  stops at well center when servicing the driller side fingerboard. When the pin  402  is extended, it abuts the shock absorber  408  and the pipe handler  350  stops at well center when servicing the off driller side fingerboard. 
     The plungers  405 ,  407  move hydraulic fluid through an orifice in the shock absorbers  406 ,  408  to provide controlled deceleration of the pipe handler before it stops, thus protecting against impact loading. 
       FIGS. 8A and 8B  show a pipe handling head A according to the present invention for a pipe handler according to the present invention (like the pipe handler  50 ) which has a body  502  with arms  504  interconnected with the body  502  by four links  506  (like the links  68 ) and two links  508  (like the links  69 ). Each arm  504  has a compliant flipper structure  505  (like the flippers  66  and their associated structure). 
     As shown in  FIG. 8A  the arms  504  are spaced-apart a maximum distance and an opening  509  is at a maximum. As shown in  FIG. 8B , the arms  504  have been moved together as closely as possible. Using the four links  506  insures that the arms  504  move parallel to each other throughout their range of motion. 
       FIG. 8A  illustrates the position of the arms  504  when the pipe handling head A is being moved into position down rows of a fingerboard between pipes in adjacent rows.  FIG. 8B  illustrates the position of the arms  504  when they have been moved to hold a pipe and move it. 
       FIG. 9A and 9B  show an embodiment of the pipe handling head A in which one flipper  505  has been deleted. 
       FIGS. 10A and 10B  show a pipe handling head B according to the present invention which has a body  542 , an arm  544  connected to the body  542 , an arm  546  connected to the body  542  via links  545  and  547 , and a compliant flipper structure  548  on the arm  546 . The links  545  and  547  are pivotably connected at one end to the body  542  and at the other end to the arm  546 . 
     As shown in  FIG. 10B , the arms  546  have been moved away from the arm  544  and the links  545  and  547  have pivoted with respect to the body  542 . 
     The present invention, therefore, provides in at least some embodiments, a pipe handler for handling pipe in a fingerboard, the fingerboard having a plurality of spaced-apart fingers for supporting a plurality of pieces of pipe, the pipe handler including: a pipe handling head having a head width; a distance comprising a second width, the second width including the distance between two fingers of the finger board and twice the width of one finger; and the head width less than the second width to facilitate movement of the pipe handling head along a row between the two fingers. Such a pipe handler (and also any pipe handler according to the present invention) may have one or some (in any possible combination) of the following: extension apparatus for moving the pipe handling head, the extension apparatus having a first end and a second end, carriage apparatus, the first end of the extension apparatus connected to the pipe handling head, the second end of the extension apparatus connected to the carriage apparatus, and track structure, the carriage apparatus movable on the track structure so that the pipe handling head can access pipe on the fingerboard; locking apparatus for selectively locking the carriage apparatus in place on the track structure; the locking apparatus having a plurality of spaced-apart wedge members on the track with a plurality of lowermost areas, one of said lowermost areas between each pair of wedge members, and powered piston apparatus on the carriage with an extendable rod for receipt in a lowermost area to lock the carriage in place on the track; the pipe handling head having at least one movable arm movable with respect to a pipe on the fingerboard to facilitate engagement of the pipe by the pipe handling head; the at least one moveable arm is two opposed movable arms; at least one flipper movably connected to the at least one movable arm, the at least one flipper projecting inwardly of the at least one movable arm, the at least one flipper constantly biased inwardly with respect to the at least one movable arm, and the at least one flipper for maintenance of a pipe in position in the pipe handling head; the at least one moveable arm is two opposed movable arms, the at least one flipper includes a flipper movably connected to each arm, and the flippers biased toward each other; wherein the pipe handling head has a body and the arms are connected to the body for parallel movement with respect to each other; wherein the carriage is movable above the track; wherein the carriage is movable below the track; a base, rotation apparatus rotationally mounted on the base, and the extension apparatus connected to the rotation apparatus; stop apparatus for limiting movement of the pipe handler and for positioning the pipe handler in a desired position with respect to a well center; and/or wherein the stop apparatus includes shock absorbing apparatus for controlled deceleration of the pipe handling head as the pipe handling head approaches a stop point. 
     The present invention, therefore, provides in at least some embodiments, a pipe handler for handling pipe in a fingerboard, the fingerboard having a plurality of spaced-apart fingers for supporting a plurality of pieces of pipe, the pipe handler including: a pipe handling head having at least one movable arm movable with respect to a pipe on a fingerboard to facilitate engagement of the pipe by the pipe handling head; at least one flipper movably connected to the at least one movable arm; the at least one flipper projecting inwardly of the at least one movable arm; the at least one flipper constantly biased inwardly with respect to the at least one movable arm; and the at least one flipper for maintenance of a pipe in position in the pipe handling head.

Summary:
Methods and systems for transferring pipe (including tubulars such as casing, tubing, drill pipe, etc.) or stands of pipe from one location to another in a wellbore derrick, e.g. from a fingerboard to a well center.