Patent Publication Number: US-9839999-B2

Title: Embedded element pulling apparatus

Description:
FIELD 
     The present invention generally relates to an embedded element pulling apparatus. More specifically it relates to an embedded element pulling apparatus having a pair of jaws for grasping an embedded element, each jaw is coupled to a linear guide, and the pair of jaws is driven along the linear guides by a motive device to grasp, remove and release the embedded element. 
     BACKGROUND 
     Removing nails from wood is a common occurrence in the building trades. In most situations the craftsman needs to only remove a few nails that may have been driven into the wood improperly or whose removal is required to adjust for a minor modification to the structure being built. For these situations the use of the claws of a hammer or a crowbar is sufficient to remove the nails. However, in certain situations such as a major renovation or during the disassembling and moving a structure (barn or house) to a new location, hundreds or even thousands of nails may need to be removed. Usually in these situations preserving the integrity of the wood for reuse is also important. Using a hammer or crowbar to remove a large number of nails is time consuming and can result in significant damage to the wood. The current disclosure provides for a new tool that greatly reduces the time and effort of pulling nails as well as minimizes the damage to the wood. Given the high cost of lumber, recycling the materials of an entire building is also possible with this new tool. The proposed embedded element pulling apparatus further has embodiments that allow the apparatus to remove staples, screws and other embedded elements from a wide variety of materials. 
     SUMMARY 
     One aspect of the present disclosure is directed to an embedded element pulling apparatus having a grasping end. The apparatus comprises a pair of linear guides separated by a width, each linear guide having a length and an inner guide surface, the inner guide surface angled to form a closing ramp at the grasping end. A jaw is paired with each linear guide, each jaw is engaged to follow along the inner guide surface. A lock assembly is integrated to lock and unlock the jaws. A carriage cooperatively couples the jaws and the lock assembly. A positioning actuator engages with the carriage to position the jaws along the length of the linear guides and a drive actuator engages with the carriage to close the jaws, pull the embedded element, and open the jaws. 
     Another aspect of the present disclosure is directed to an embedded element pulling apparatus having teeth associated with each jaw that are interchangeable to vary the precision of how the embedded element is grasped and the type of embedded elements that may be removed. 
     Another aspect of the present disclosure is directed to an embedded element pulling apparatus having a width adjustment assembly for adjusting the width between the pair of linear guides to adjust for the size of the embedded element and gripping strength desired to grip the embedded element during removal. 
     Yet another aspect of the present disclosure is directed to an embedded element pulling apparatus having a receptacle for collecting removed embedded elements. 
     Still another aspect of the present disclosure is directed to an embedded element pulling apparatus having a motive device coupled with the jaws to pull the embedded element between grasping and un-grasping positions. The motive device is interchangeable with other motive devices that operate using mechanical, electric, magnetic, hydraulic, pneumatic and explosive principles to accommodate to different work environments. 
     Still yet another aspect of the present disclosure is directed to a motive device comprising a tube. The tube includes a tube wall, a tube interior, a tube exterior, opposite tube ends and a longitudinal axis. A tube end cap is proximate each tube end, each tube end cap has a large radius section and small radius section. Each large radius section is mounted to the interior of the tube so that each small radius section extends outward to form a valve gap between the tube wall and each small radius section. A pressure reservoir surrounds the tube exterior. The pressure reservoir has a reservoir end cap paired with each valve gap. Each reservoir end cap has a valve element fitting within each valve gap. A piston positioned within the tube&#39;s interior is movable along the longitudinal axis between the tube end caps. A trigger moves the pressure reservoir along the longitudinal axis relative to the tube allowing fluid to pressurize one side of the piston while venting the other side of the piston to move the piston. The valve element switches connection of the tube between exhaust and the pressure reservoir. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The foregoing and other aspects and advantages of the invention will be apparent from the following detailed description, as illustrated in the accompanying drawings, in which: 
         FIG. 1 a    is a perspective view of an embedded element pulling apparatus according to one embodiment of the invention that shows the grasping assembly integrated with a motive device; 
         FIG. 1 b    is a sectional, perspective view of the embedded element pulling apparatus in  FIG. 1 a   , with hatching left off for clarity; 
         FIG. 2  is an exploded view of the embedded element pulling apparatus illustrated in  FIGS. 1 a  and 1 b    showing that the motive device is separable from the grasping assembly and replaceable with other motive devices; 
         FIG. 3  is a partial cutaway, perspective view of the embedded element pulling apparatus illustrated in  FIGS. 1 a  and 1 b    showing the carriage assembly integrated with linear guides, but apart from the housing of the grasping assembly; 
         FIG. 4  is a partially-exploded and partially-cutaway, perspective view of the components of  FIG. 3 ; 
         FIG. 5 a    is a top, plan view of the carriage assembly of  FIG. 3  showing the locking assembly unlocked; 
         FIG. 5 b    is a top, plan view of the carriage assembly of  FIG. 3  showing the locking assembly locked; 
         FIG. 6 a    is a perspective view of the linear guides for the embedded element pulling apparatus illustrated in  FIGS. 1 a    and  1   b;    
         FIG. 6 b    is a partial cutaway, perspective view of the linear guides illustrated in  FIG. 6   a;    
         FIG. 7 a    is a back view of gasping assembly with carriage assembly hidden for the embedded element pulling apparatus of  FIGS. 1 a    and  1   b;    
         FIG. 7 b    is a back view of grasping assembly with carriage assembly hidden for the embedded element pulling apparatus of  FIGS. 1 a    and  1   b;    
         FIG. 8 a     1  is a side, sectional view of the linear guides of  FIG. 7 a    along line  8   a   1 - 8   a   1  adjusted to a narrow width; 
         FIG. 8 a     2  is top, plan, partial cutaway view of the linear guides in  FIG. 7 b    along line  8   a   2 - 8   a   2  adjusted to a narrow width; 
         FIG. 8 b     1  is a side, sectional view of the linear guides of  FIG. 7 a    along line  8   b   1 - 8   b   1  adjusted to a wide width; 
         FIG. 8 b     2  is top, plan, partial cutaway view of the linear guides in  FIG. 7 b    along line  8   b   2 - 8   b   2  adjusted to a wide width; 
         FIG. 9  is a side, sectional view of one embodiment of the motive device of the embedded element pulling apparatus illustrated in  FIGS. 1 a    and  1   b;    
         FIG. 10 a    is an enlarged view of the dashed outline in  FIG. 9  with the valve configuration in the exhausting state; 
         FIG. 10 b    is an enlarged view of the dashed outline in  FIG. 9  with the valve configuration in the pressurizing state; 
         FIG. 11 a    is a side view of the grasping assembly of the embedded element pulling apparatus of  FIGS. 1 a  and 1 b    indicating the section views used in  FIGS. 11 b   - f;    
         FIG. 11 b    is a top sectional view of the grasping assembly of  FIG. 11 a    along line A-A indicating a first step in grasping and removing an embedded element; 
         FIG. 11 c    is a top sectional view of the grasping assembly of  FIG. 11 a    along line A-A indicating a second step in grasping and removing an embedded element; 
         FIG. 11 d    is a top sectional view of the grasping assembly of  FIG. 11 a    along line A-A indicating a third step in grasping and removing an embedded element; 
         FIG. 11 e    is a top sectional view of the grasping assembly of  FIG. 11 a    along line A-A indicating a fourth step in grasping and removing an embedded element; 
         FIG. 11 f    is a top sectional view of the grasping assembly of  FIG. 11 a    along line A-A indicating a fifth step in grasping and removing an embedded element; 
         FIG. 12 a    is a side view of the motive device of the embedded element pulling apparatus of  FIG. 1  indicating the section views used in  FIGS. 12 b   - f;    
         FIG. 12 b    is a top sectional view of the motive device of  FIG. 12 a    along line B-B corresponding with the first step of the grasping assembly shown in  FIG. 11   b;    
         FIG. 12 c    is a top sectional view of the motive device of  FIG. 12 a    along line B-B corresponding with the second step of the grasping assembly shown in  FIG. 11   c;    
         FIG. 12 d    is a top sectional view of the motive device of  FIG. 12 a    along line B-B corresponding with the third step of the grasping assembly shown in  FIG. 11   d;    
         FIG. 12 e    is a top sectional view of the motive device of  FIG. 12 a    along line B-B corresponding with the fourth step of the grasping assembly shown in  FIG. 11   e;    
         FIG. 12 f    is a top sectional view of the motive device of  FIG. 12 a    along line B-B corresponding with the fifth step of the grasping assembly shown in  FIG. 11   f;    
         FIG. 13 a    is a perspective view of the jaw of the embedded element pulling apparatus of  FIGS. 1 a    and  1   b;    
         FIG. 13 b    is an exploded view of the jaw in  FIG. 13 a    showing how the interchangeable tooth is attached to the jaw; 
         FIG. 13 c    is a perspective view of one embodiment of an interchangeable tooth that may be used in the embedded element pulling apparatus of  FIGS. 1 a    and  1   b;    
         FIG. 13 d    is a perspective view of another embodiment of an interchangeable tooth that may be used in the embedded element pulling apparatus of  FIGS. 1 a    and  1   b;    
         FIG. 13 e    is a perspective view of yet another embodiment of an interchangeable tooth that may be used in the embedded element pulling apparatus of  FIGS. 1 a    and  1   b;    
         FIG. 13 f    is a perspective view of yet another embodiment of an interchangeable tooth that may be used in the embedded element pulling apparatus of  FIGS. 1 a    and  1   b;    
         FIG. 13 g    is a perspective view of yet another embodiment of an interchangeable tooth that may be used in the embedded element pulling apparatus of  FIGS. 1 a    and  1   b;    
         FIG. 13 h    is a perspective view of another embodiment of a combined set of interchangeable teeth that may be used in the embedded element pulling apparatus of  FIGS. 1 a    and  1   b;    
         FIG. 13 i    is a perspective view of yet another embodiment of an interchangeable tooth that may be used in the embedded element pulling apparatus of  FIGS. 1 a  and 1 b   ; and 
         FIG. 13 j    is a perspective view of yet another embodiment of an interchangeable tooth that may be used in the embedded element pulling apparatus of  FIGS. 1 a    and  1   b.    
     
    
    
     DETAILED DESCRIPTION 
     Embedded element pulling apparatus  20  is shown in  FIGS. 1 a  and 1 b   . Embedded element pulling apparatus  20  comprises an embedded element grasping assembly  22  and a motive device  24 . Grasping assembly  22  is preferably separable from the motive device as shown in  FIG. 2  so that the grasping assembly can be powered by different motive devices to accommodate to different work environments. In other embodiments embedded element pulling apparatus  20  may be fabricated as an integrated device with both the grasping assembly  22  and motive device  24  permanently contained within the same housing  25 . Although  FIGS. 1, 2, 9, 10 and 12  show a specific type of pneumatic motive device  24 , it is understood that the motive device could be any one of a wide variety of alternative motive devices that operate by using mechanical, electric, magnetic, hydraulic, pneumatic and explosive principles. 
       FIG. 3  shows embedded element pulling apparatus  20  comprises a pair of linear guides  26  separated by a width  29 . Each linear guide  26  has a length and an inner guide surface  28 . Inner guide surface  28  is angled to form a closing ramp  30  at the grasping end  32 . A jaw  34  is paired with each linear guide  26 . Each jaw  34  is engaged to follow along inner guide surface  28 . Lock assembly  36  is integrated to lock and unlock jaws  34  respectively at the grasping and un-grasping positions. Carriage assembly  37  includes carriage  38 , jaws  34  and lock assembly  38 . Carriage  38  cooperatively couples jaws  34  and lock assembly  36 . Linear guides  26 , carriage  38 , jaws  34  and lock assembly  36  are assembled to reside within housing  25  of grasping assembly  22 . Housing  25  has a grasping opening  39  and may have a viewing opening  41  for observing alignment of tooth  50  to embedded element  42  and the operation of the components within the housing. Positioning actuator  40  extending from motive device  24  engages carriage  38  to position jaws  34  along the length of linear guides  26  between the grasping and un-grasping positions prior to pulling embedded element  42 . Positioning actuator  40  may be a stand-alone component such as a constant force spring, linear spring or small gas spring that repositions carriage assembly  37  proximate to grasping end  32  of grasping assembly  22 . Positioning actuator  40  may also be coupled to a motive device that provides motion to the positioning actuator; this is the case when using position shaft  78  combined with motive device  24 , position chamber  107  residing within shaft  80 , and orifice  126  to fill the chamber. Drive actuator  44  extending from motive device  24  engages with carriage  38  via retraction element  46  to close jaws  34 . Drive actuator  44  is a mechanically engaging element coupled to a motive device that provides force and motion. Drive actuator  44  may be drive shaft  80  coupled with motive device  24  as described in the present disclosure. Drive actuator  44  may also include other components such as a rotary motor, a linear motor, a pneumatic cylinder, a hydraulic cylinder or an internal combustion cylinder. When jaws  34  are securely closed onto embedded element  42 , drive actuator  44  is moved away from grasping end  32  to remove the embedded element from the embedding material  45 . When drive actuator  44  reaches un-grasping end  48 , lock assembly  36  unlocks and releases the embedded element  42 . 
     In  FIG. 4 , linear guides  26  have been exploded away to better show how carriage  38  couples jaws  34  and lock assembly  36 . Each jaw  34  is an elongated, curved structure that is symmetrically and cooperatively closeable. The jaw grasping end  47  of each jaw  34  terminates with an interchangeable tooth  50 . The jaw locking end  49  of each jaw  34  is connected by an arm pivot  51  to one of the two locking arms  52  of lock assembly  36 . Proximate the midpoint along the length of each jaw  34  is a jaw pivot  54 . Jaw pivot  54  of each jaw  34  engages carriage  38  along jaw pivot slot  35  and allows for the pivoting action that enables the jaw to grasp an embedded element  42  at jaw grasping end  47  and lock the jaw at jaw locking end  49 . The structure of jaw pivot  54  is such as to have a radius that extends beyond the outer edge of each jaw and provides a rolling or sliding surface to engage with the inner surface  28  of the corresponding linear guide  26 . Jaw pivot  54  moves along inner surface  28  and within linear guide slot  55 . Each linear guide  26  may have a pair of linear guide slots  55 , one on the top and one on the bottom. A grasping guide  56 , located forward of the jaw pivot  54  towards tooth  50 , is included on each jaw  34  to engage with closing ramp  30  to cause the grasping action of the jaw. The structure of grasping guide  56  is such as to have a radius that extends beyond the outer edge of each jaw  34  and provides a rolling or sliding surface to engage with the inner surface  28  of the corresponding linear guide  26 . Grasping guide  56  also aids with the smooth closing of jaw  34  by moving against the closing ramp  30 . The jaw grasping ends  47  of the pair of jaws  34  are kept separated by jaw bias  57  that pushes the jaws apart until the jaws are forced to grasp embedded element  42  when grasping guide  56  is forced against closing ramp  30 . 
       FIGS. 5 a  and 5 b    illustrate how lock assembly  36  is integrated with carriage  38  to enable locking and unlocking of jaws  34 . Lock assembly  36  is configured to be an over-center lock assembly that includes a lock activation element  58  and two locking arms  52 . The two locking arms  52  are connected to lock activation element  58  at their inner ends by lock pivot  60  and to jaws  34  by respective arm pivots  51  at their jaw ends. Lock pivot  60  has an extension, lock pin  61 , extending from the lock pivot. Lock pivot  60  moves along lock guide slot  62  within carriage  38 . Arm pivots  51  move within lock activation slot  64  that is channeled within carriage  38 . Lock bias  66  provides a bias that pushes on lock activation element  58 . Lock activation occurs when lock pivot  60  is pulled away from the grasping end by locking arms  52  and pushed by lock bias  66  beyond the center line. The center line being defined by the line connecting arm pivots  51 . Unlocking occurs when carriage assembly  37  is pulled away from grasping end  32  and lock pin  61  hits a fixed element  67  on the inside of housing  25 . Fixed element  67  pushes lock pivot  60  beyond the center line of lock activation slot  62  causing jaws  34  to open and thereby releasing embedded element.  42 . 
     Linear guides  26  are shown in  FIGS. 6 a  and 6 b   . Linear guides  26  are two parallel and symmetric linear guides forming a pair of linear guides. Each linear guide  26  has a length and an inner guide surface  28 . Inner guide surface  28  is angled to form a closing ramp  30  at the grasping end  32 . Having the closing ramp  30  of each linear guide  26  turn inward towards the middle of grasping assembly  22  provides the necessary structure for closing jaws  34  onto an embedded element  42 . Each linear guide  26  further includes a linear guide slot  51  for guiding jaw pivot  54 . Linear guides  26  are separated by a width  28 . The width between linear guides  26  may be adjusted to accommodate the pulling of different sized embedded elements  42  and the amount of grasping force imparted to teeth  50  for holding onto the shank of the embedded element  42 . 
     Width adjustment occurs via the use of a width adjustment assembly  68  shown in  FIGS. 7 a - b  and 8 a     1 - 8   b   2 . With adjustment assembly  68  is incorporated as part of embedded element pulling apparatus  20  in grasping assembly  22 . Width adjustment assembly  68  includes at least one pair of diagonal guide elements  70 , one element associated with each linear guide  26 . It is preferably to have two diagonal guide elements  70  in each linear guide  26 , one diagonal guide element near the grasping end and one diagonal guide element near the locking end of each linear guide. Two diagonal guide elements  70  provide for smoother adjustment. Diagonal guide elements  70  include a fixed guide and a mobile element  72  that is constrained by and moves relative to the fixed guide element. Examples of fixed guides are a slot, groove or channel. Examples of mobile elements  72  are a key, a key and spring, balls, a linear bearing or rollers. Diagonal guide elements  70  constrain linear guide  26  to move along the length of the diagonal guide element. This structure keeps the linear guides  26  parallel while being able to change width  28 . Closing fork  74  in cooperation with positioner  76  allows the user to change the width between linear guides  26 . Each side of closing fork  74  is connected to one of the linear guides. Positioner  76  translates linear guides  26  along the length of housing  25 , which in turn causes the linear guides to widen or narrow as they follow translatable guide elements  70 . Positioner  76  may be threaded or have a cam to move the positioner relative to housing  25 . 
     Movement of carriage assembly  37  within grasping assembly  22  and along linear guides  26  is governed by one of two actuators, either by positioning actuator  40  or drive actuator  44 . Positioning actuator  40  may include a positioning shaft  78  and possibly other components to enable the positioning actuator to set the position of carriage assembly  37 . Drive actuator  44  includes a drive shaft  80  in cooperation with retraction element  46  and possibly other components to provide a drive force to the carriage assembly  37 . Drive actuator  44  is able to move independently of carriage  38 . In a preferred embodiment, positioning actuator  40  is concentric to and resides within drive actuator  44 . However in other embodiments, positioning actuator  40  may reside parallel to the drive actuator  44 , but not necessarily concentric to the drive actuator. Positioning actuator  40  is used to move carriage assembly  37  from the un-grasping end  48  to grasping end  32  of grasping assembly  22  so that the carriage assembly can be in a ready position with jaws  34  open and ready to be driven against closing ramp  30 . Drive actuator  44  is used to drive jaws  34  against closing ramp  30 , close the jaws and active lock assembly  36 . Drive actuator  44  further includes a retraction element  46 . Retraction element  46  is for engaging with carriage assembly  37  so that the carriage assembly can be pulled along linear guides  26  away from grasping end  32 . Retraction element  46  has two retraction arms  86  with corresponding retraction gaps  88 . When lock assembly  36  is in the locked state the jaw ends of locking arms  52  fit securely within retraction gaps  88  allowing carriage assembly  37  to be pulled away from grasping end  32 . 
     Several other elements are incorporated as part of grasping assembly  22 . Grasping assembly  22  includes a disposal slot  90  within housing  25  for disposal of pulled embedded elements  42 . An optional embedded element receptacle  92  may be attached to housing  25  to collect removed embedded elements. Disposal slot  90  is aligned with embedded element receptacle  92 . Integrated with housing  25  is a handle  94  for ergonomic holding of embedded element pulling apparatus  20 . A trigger  96  is also integrated with handle  94 . Pressing trigger  96  initiates closure of jaws  34  onto embedded element  42  after the user has aligned embedded element pulling apparatus  20  to the embedded element. Releasing trigger  96  initiates the jaws to pull embedded element  42  and bring the embedded element to receptacle  92  for collection and disposal. 
     Various types of motive device  24  can be connected to grasping assembly  22  to support movement of positioning actuator  40  and drive actuator  44 .  FIG. 9  show a specific motive device  24  that uses pneumatic or hydraulic principles. The uniqueness of motive device  24  is that the motive device can provide a high rate of fluid delivery and exhaust to the chambers on either side of piston  100  and thereby create fast actuation with high impact force for drive actuator  44 . Motive device  24  comprises a tube  102 . Tube  102  has a tube wall, a tube interior, a tube exterior, opposite tube ends and a longitudinal axis L. Tube end caps  104  are fitted proximate each tube end. Tube end caps reside a short distance inside from the ends of tube  102 . Each tube end cap has a large radius section  105  and a small radius section  106 . Each large radius section  105  is mounted to the interior wall of tube  102  with small radius section  106  extending outward from the center of the tube. Each small radius section  106  forms a valve gap  108  between the inside wall of tube  102  and each small radius section. The interior tube volume is bounded by the interior tube wall surface and interior surfaces of both tube end caps  104 . A piston  100  is positioned in the interior tube volume and movable along longitudinal axis L. Piston  100  is movable along between both tube end caps  104 . Piston  100  has a first piston side  110   a  and a second piston side  110   b . A pressure reservoir  112  surrounds the exterior of tube  102 . Pressure reservoir  112  has a pressure source inlet  113  from an external pressure source. Pressure reservoir  112  has two reservoir end caps  114 , each reservoir end cap is paired with a valve gap  108 . Each reservoir end cap has a valve element  116  fitting within each valve gap  108 . Trigger  96  connects with motive device  24  so that the trigger facilitates the movement of pressure reservoir  112  along longitudinal axis L relative to tube  102 . The alternating movement of reservoir  112  relative to tube  102  allows fluid to pressurize one side of piston  100  while venting the other side of the piston thereby causing the piston to move between the two ends of tube  102 . 
       FIGS. 10 a  and 10 b    detail the valve structures for motive device  24  and how the valves work. Note that the valve structures themselves are symmetric relative to both ends of motive device  24 . Movement of pressure reservoir  112  relative to tube  102 , initiated by trigger  96 , is what changes the state of each valve at the two ends of motive device  24 . Each valve element  116  has a pressure seal  118  around the interior of tube wall  102  for sealing between the interior wall of tube  102  and the valve element. Tube  102  has at least one tube opening  120 . It is preferable to have a plurality of tube openings  120  around the circumference of the tube that lead from reservoir  112  into valve gap  108 . The more tube opening area, the faster tube  102  can be pressurized. An exhaust seal  122  around small radius section  106  provides for sealing between valve element  116  and tube end cap  104 . Each tube end cap  104  has at least one end cap opening  124 . It is preferable to have a plurality of end cap openings  124  through large radius section  105 . The more end cap opening area, the faster tube  102  can be pressurized and exhausted. In the exhausting state for first piston side  110   a ,  FIG. 10 a   , valve element  116  is moved all the way into valve gap  108  and touches large radius section  105  of tube end cap  104 . The fluid that is interior tube  102  and adjacent to first piston side  110   a  is exhausted through end cap openings  124  into valve gap  108  and around valve element  116  via exhaust gap  117 . During this state, pressure seal  118  stops fluid in pressure reservoir  112  from escaping and allows pressure to build within the pressure reservoir. In the pressurizing state for first piston side  110   a ,  FIG. 10 b   , valve element  116  is moved away from large radius section  105  of tube end cap  104 . A new seal is created between valve element  116  and exhaust seal  122 . Pressure seal  118  then moves past the tube openings  120  and allows fluid to flow from pressure reservoir  112  through tube openings  120  into valve gap  108  and into the interior of tube  102  through end cap openings  124 . The valve states are opposite (pressuring or exhausting) for each end of motive device  24 . When the valve on one end is open the valve on the other end is closed. The novel structure of a plurality of tube openings  120  and plurality of end cap openings  124  allows fluid to be transferred from pressure reservoir  112  very quickly. This novel structure also allows fluid to be exhausted from inside tube  102  very quickly. 
     The embedded element pulling apparatus  20  described requires a large amount of energy/momentum to be imparted to drive actuator  44  so that jaws  34  will be able to embed into embedded material  45 , grab around the shank of embedded element  42  and pull the embedded element out of the embedded material. For this reason the motive element  24  shown in  FIGS. 1, 2, 9, 10 and 12  is a preferred embodiment for the motive element. The plurality of tube openings  120  and end cap openings  124  can provide 20 to 30 times the area of a pressurized hose. When this large pressure area is combined with the proximity of a local pressure reservoir  112 , quick pressure delivery and quick exhaust can be provided to drive actuator  44 . This allows for a high momentum apparatus to be attained. Embedded element pulling apparatus  20  can attain a cycle of grasping and removing embedded element  42  in less than one second and preferably less than one tenth of a second. 
     Piston  100  may drive a variety of configurations of actuation elements. Piston  100  may have a single shaft existing one end of tube  102 . Piston  100  could have two shafts, one exiting both ends of tube  102 . Piston  100  may also have two shafts exiting one end of tube  102 . This configuration is the preferred embodiment for providing actuation to grasping end  22  of embedded element pulling apparatus  20 . In this configuration position shaft  78  is concentric with drive shaft  80  and moves within the drive shaft. At the end of drive shaft  80  that resides within the interior cavity of tube  102  is a small orifice  126 . When drive shaft  80  is pulled back within the interior of tube  102 , orifice  126  provides a pathway for pressurized fluid to reach the back end of positioning shaft  78  filling position chamber  107 . The fluid extends positioning shaft  78  out of drive shaft  80 . This action is useful in positioning carriage assembly  37  into a ready state near grasping end  32 . 
       FIGS. 8 a     1 ,  8   b   1  and  9  show one embodiment for trigger  96  and how the trigger may be integrated as part of embedded element pulling apparatus  20  to activate motive device  24 . A rod  125  connects trigger  96  to the housing of pressure reservoir  112 . When trigger  96  is pulled, rod  125  pushes pressure reservoir away from grasping assembly  22 . When trigger  96  is released, a trigger bias element  127  in the motive element (the trigger bias element could be located in housing assembly as well), returns pressure reservoir  96  to the forward position closer to grasping assembly  22 . When trigger  96  is pulled, motive element  24  that powers drive actuator  44  is energized. This causes the forward motion of carriage assembly  37  and drives teeth  50  to grasp embedded element  42 . When trigger  96  is released, the reverse motion of drive actuator  44  is energized. This causes embedded element  42  to be pulled backwards and released. Several alternative implementations of trigger  96  are possible. These alternatives may include using a pneumatic or hydraulic valve, actuated by trigger  96 , which in turn activates a small pneumatic or hydraulic actuator to push and pull on the housing of pressure reservoir housing  112 . In another alternative implementation, drive actuator  44  maybe coupled with an electrical or magnetic motive device, trigger  96  would activate an electrical switch to energize the motion. Similarly, such an electrical switch could activate an internal combustion or explosive motive device. 
     As shown in  FIG. 2 , grasping assembly is connected to motive device via a fastener assembly  128 . The specific fastener assembly  128  in  FIG. 2  is four screws  130  securing two arms  132  mounted to grasping assembly  22  that are attached to the front face of motive device  24 . However, it is understood that fastener assembly  128  could take the form of various structures that include one or more fasteners from the group including screws, a twist lock, a snap ring and pins. 
     The operation of embedded element pulling apparatus  20  is shown in two corresponding series of figures.  FIGS. 11 a -11 f    illustrate the workings of grasping assembly  22  and  FIGS. 12 a -12 f    illustrate the corresponding workings of motive device  24 . In the ready position,  FIGS. 11 b  and 12 b   , the teeth  50  proximate grasping opening  39  of embedded element pulling apparatus  20  are aligned to either side of embedded element  42 . In this position, carriage assembly  37  is forward and located at the base of closing ramps  30 . Jaws  34  are open. Lock assembly  36  is unlocked. Drive shaft  80  is retracted back into motive device  24 . The user then pulls trigger  96 . Pulling trigger  96  facilitates the movement of pressure reservoir  112  in a direction away from grasping assembly  22 . This action cause first piston side  110   a  to be exhausted and second piston side  110   b  to be pressurized. Piston  100  moves drive shaft  80  with attached retraction element  46  to engage carriage  38 ,  FIGS. 11 c  and 12 c   . Piston  100  continues pushing drive shaft  80 , which moves carriage assembly  37  forward up closing ramps  30 ,  FIGS. 11 d  and 12 d   . As jaws  34  are closed, the jaws grasp onto the shank of one embedded element  42  to engage opposite sides of the embedded element. Locking arms  52  are pushed beyond the center line so that the jaw ends of locking arms  52  fit securely within retraction gaps  88 . The user then releases trigger  96 . Releasing trigger  96  facilitates the movement of pressure reservoir  112  in a direction towards grasping assembly  22 . This causes first piston side  110   a  to be pressurized and second piston side  110   b  to be exhausted. Piston  100  moves drive shaft  80  with carriage assembly  37  securely attached to be pulled away from grasping end  32  until lock pin  61  of the carriage assembly reaches fixed element  67  on the inside of housing  25 ,  FIGS. 11 e  and 12 e   . Carriage assembly  37  continues to move towards motive device  24  causing fixed element to move lock pin  61  back over the centerline and release embedded element  42 . Embedded element  42  then drops through disposal slot  90  and into receptacle  92 . Fluid slowly bleeds through orifice  126  to move positioning shaft  78  with carriage assembly  37  to the ready position. 
     Different types of interchangeable grasping teeth  50  may be incorporated with embedded element pulling apparatus  20  depending on the type of embedded element  42  to be removed and the precision with which the embedded element must be removed.  FIGS. 13 a - j    illustrate how teeth  50  are attached to jaw  34  and the different types of teeth that can be used depending on the job at hand. Each grasping tooth  50  has a tooth width, a tooth grasping end and a generally arched shape that thins towards the tooth grasping end. Each tooth  50  has a tooth guide  134  that extends beyond the width of the tooth and slideably fits within a tooth slot  136  in each jaw. Each tooth is held in place by a tooth fastener  138 . Tooth fastener  138  may pass within a tooth fastener opening  140  in both jaw  34  and tooth  50 . Some teeth  50  may include a shank notch  142  at the grasping end. 
     More precision during removal of embedded elements  42  generally equates to less damage to the embedding material  45  during the removal process by localizing damage from the grasping teeth  50  to only a short distance on either side of the embedded element. More precision, however, requires tighter tolerances and more accurate positioning of the embedded element pulling apparatus  20  when aligning teeth  50  to embedded element  42 . In some situations, the user may not care about damage to embedding material  45  and therefore use wider teeth  50 , in favor of narrower more precise teeth, in order to more quickly complete the job. However, in other situations the user may care about damage to the embedding material  45  and therefore use narrower, more precise teeth and relinquish the speed at which the job can be completed in favor of improving the quality of the embedding material after the job is complete.  FIGS. 13 c - e    illustrate a series of four teeth  50 , the teeth are shown from most precise  FIG. 13 c    to the least precise  FIG. 13 f   . Other examples of teeth  50  are a general purpose tooth  FIG. 13 g   . A pair of teeth for removing staples  FIG. 13 h   . A tooth for removing square nails  FIG. 13 i    and a cutter tooth in  FIG. 13   j.    
     While several embodiments of the invention, together with modifications thereof, have been described in detail herein and illustrated in the accompanying drawings, it will be evident that various further modifications are possible without departing from the scope of the invention. Nothing in the above specification is intended to limit the invention more narrowly than the appended claims. The examples given are intended only to be illustrative rather than exclusive.