Abstract:
An assembly and method for releasably connecting a gripper finger to a robotic arm needing only manual manipulation to operate. The assembly includes a finger body having a quick-change bar connected to a locking lever. The locking lever can be rotated by hand to engage and disengage the assembly to connect a finger to a gripper connected to a robot. The locking lever provides a sleeve and pin which interact to lock the assembly. The sleeve and pin can have recessed surfaces formed to interact with roll pins or screws to restrict behavior of the quick-change device during engagement.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based on U.S. Provisional Patent Application No. 61/268,352, filed Jun. 11, 2009, on which priority of this patent application is based and which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0002]    The most common tool that is used on manipulators mounted on mobile robots is a gripper, which allows the robot to grasp and move objects to fulfill their operational requirements. However, no single gripper design is optimal for all tasks, which is a problem for grippers on mobile robots, since their tasks are unstructured, vary widely, and change frequently. One way to customize a gripper for a specific task is to design a set of fingers, also called jaws, for the gripper that is specific to that task. For example, a task requiring a robot to reach deep inside a narrow opening might benefit by having a set of long, narrow fingers. However, long, narrow fingers would not be suited to lifting and controlling large masses, where a shorter, broader finger would provide optimal control. For tasks involving grasping of a small or fragile object, a gripper with a compliant gripping facial surface is desirable. However, those compliant surfaces deteriorate quickly and are replaced frequently; therefore, the ability to quickly install replacements in the field is an advantage. 
         [0003]    Currently deployed systems use grippers with fingers that are permanently installed during assembly, and are only repaired or replaced in a factory or depot setting. This limits the effectiveness of the robot/manipulator to missions which can be achieved with specific installed fingers. Even grippers with replaceable fingers typically require a technician to replace the fingers which require time, materials, and special tools which are not always readily available in the field. Particularly, in time critical applications, such as military or civilian Explosives Ordinance Disposal (EOD), this process interferes with completing missions in a timely way. For these scenarios, there exists a need to change gripper fingers quickly. 
         [0004]    Military and law enforcement groups are increasingly relying on UGVs to perform life-threatening tasks ranging from under car inspection to EOD. As small UGVs, such as Omni-Directional Inspection Systems (ODIS), Talon and Packbot have gained acceptance, the variety of tasks they have been required to perform has increased. 
         [0005]    In addition, unlike industrial robots, these systems are deployed in uncontrolled environments. They must have a robust design to survive the normal working environment they will encounter, both during deployment on the mobile robot and when the manipulator and tools are being stored or transported. The mechanical connection must be resilient to minor variations in tolerances of mating components, such as might occur when a tool is dropped or bumps against another tool in the toolbox, or such as might be caused by the presence of debris, such as dirt and sand, from the working environment. 
         [0006]    Robotic arms often require specialized configurations to accomplish their particular mission, requiring change in the length of a link in the arm or attaching a different end effector or tool. 
         [0007]    An object of the present invention is to provide a quick-release assembly for separating robotic gripper fingers mechanically from their manipulator arms, thus allowing unhindered integration of fingers as the complexity of the system is contained in the manipulator arms. A further object is to make the gripper fingers replaceable units that can be replaced by hand when they fail. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention is an assembly for releasably connecting a gripper finger to a robotic arm having a gripper having a first and second arm and a cylindrical gripper bar connecting the arms. The arms have parallel circular cavities. Opening in the cavities define a first and second lip, and a concentric recessed area positioned on an external area of the gripper arm around the cavity. A finger member can have a finger and a body. The body can have a locking lever connected to a bar extending through the finger body and a cylindrical cavity. The cavity can have a longitudinal passageway along the length of the cavity. The passageway forms a first and second lip and the gripper bar mates with the passageway of the cavity and the openings of the arms of the gripper receiving the locking bar of the finger member, wherein the locking lever is rotated and clamps the gripper to the finger member. 
         [0009]    The gripper bar can have a head and a shaft, and retaining member extending into a cylindrical cavity of the locking lever. The gripper bar can have a groove in the head of the cylindrical bar of the gripper with a retaining member engaging the groove to lock the locking bar when the cavity of the locking lever is positioned around the head of the cylindrical bar. The retaining member can be a threaded retaining pin. The locking lever can have a cavity having a threaded surface for threadably receiving to the threaded retaining pin. 
         [0010]    The locking bar of the present invention, in one embodiment, can have a pin having a flanged first end and a second end. The locking lever rotatably connects to the flanged first end of the pin and the second end of the pin can have a threaded surface. A sleeve, having an axial bore and a flanged second end connects to the pin. The axial bore of the sleeve has a threaded surface, wherein said threaded surface of the bore of the sleeve is threadably connected to the threaded surface of the second end of pin. The assembly further has a threaded member, a slotted surface between the pin and the finger body formed of a recess extending radially about the circumference of the pin, the recess can have a first and second wall and a hole through the finger body can be aligned with the slotted surface, where the threaded member is received by the hole through the gripper and into the slotted surface. The first and second wall limits vertical movement of the pin. 
         [0011]    In order to limit vertical and rotational movement of the sleeve, the sleeve can have a slotted surface defined as an opening, the opening can have an upper and lower vertical wall and symmetric side walls formed partially along the length and extending radially through the sleeve. A hole through the finger body can be in alignment with the slotted surface of the sleeve, wherein the roll pin is received by the hole and displaced through the finger body through the slotted surface into the finger body. The slotted surface of the sleeve interacts with the roll pin to limit rotational movement of the sleeve. The slotted surface interacts with the pin to limit vertical movement of the sleeve. 
         [0012]    In another embodiment, a spring can be positioned between the recess and the flanged surface of the sleeve. The spring is for adjusting the locking bar and locking lever during engagement. The locking lever and bar of the finger limits longitudinal rotation of the finger about the gripper. The gripper arms limit vertical rotation of the finger. The gripper bar and locking bar limit lateral rotation of the finger. The surfaces of the longitudinal passageway of the finger body cavity are smoothed surfaces for sliding the bar into alignment. The first and second lip of the gripper arm cavities can be chamfered for directing alignment. The finger member can connect to grippers having deviation in manufacturing. 
         [0013]    A finger member can have a finger and a body and can be designed to connect t different grippers. The body has a locking lever connected to a bar extending through the finger body and a cylindrical cavity. The cavity has a longitudinal passageway along the length of the cavity. The passageway forms a first and second lip, wherein the passageway of the cavity is operable to mate with a gripper bar of a gripper and locking bar of the finger member can mate with gripper arms of a gripper. The locking lever is operable to rotate and clamp a gripper to the finger member. The locking lever has a degree of compliance to account for variations in the gripper. 
         [0014]    The present invention further includes a method for releasably connecting a gripper finger to a robotic arm by providing a gripper having a first and second arm and a cylindrical gripper bar connecting the arms. 
         [0015]    The method further includes providing a retaining member extending into a cylindrical cavity of the locking lever, a groove in the head of the cylindrical bar of the gripper, positioning retaining member in the groove, and locking the locking bar when the cavity of the locking lever is positioned around the head of the cylindrical bar. 
         [0016]    Next, the method includes providing a pin having a flanged first end and a second end. The locking lever can rotatably connect to the flanged first end of the pin. The second end of the pin has a threaded surface. Also provided is a sleeve having an axial bore extending therethrough and a flanged second end. The axial bore has a threaded surface, connecting the threaded surface of the bore of the sleeve to the threaded surface of the second end of the pin. Rotating the locking lever by rotating the lever causes the sleeve to threadably connect. 
         [0017]    The method further includes providing a threaded member, providing a slotted surface between the pin and the finger body formed of a recess extending radially about the circumference of the pin. The recess has a first and second wall. A hole through the finger body aligned with the slotted surface is provided, receiving the threaded member by the hole through the gripper and into the slotted surface, and limiting vertical movement by the first and second wall limiting of the pin. 
         [0018]    Finally, the method provides a roll pin, providing a slotted surface of the sleeve. The slotted surface is a opening formed partially along the length and extending radially through the sleeve providing a hole through the finger body in alignment with the slotted surface of the sleeve, receiving the roll pin by the hole, displacing the roll pin through the finger body and through the slotted surface into the finger body, which limits rotational movement of the sleeve when the slotted surface of the sleeve interacts with the roll pin. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a top-perspective view of the quick-change assembly of the present invention; 
           [0020]      FIG. 2  is a side-perspective view of the quick-change finger and robotic gripper of  FIG. 1 , shown partially engaged; 
           [0021]      FIG. 3  is a sectional view of the object depicted in  FIG. 2  taken along broken lines labeled  FIG. 3  with the arrows indicating the direction of sight of the present invention; 
           [0022]      FIG. 4A  is a side view of the quick-change assembly of the present invention before it is engaged; 
           [0023]      FIG. 4B  is a side view of the quick-change assembly of the present invention partially engaged showing the progression of the finger body onto the gripper bar; 
           [0024]      FIG. 4C  is a side view of the quick-change finger resting on the robotic gripper of the present invention; 
           [0025]      FIG. 5A  is a top-perspective view of the quick-change assembly of the present invention showing the locking lever partially engaged; 
           [0026]      FIG. 5B  is a top-perspective view of the quick-change assembly of the present invention showing the locking lever fully engaged; 
           [0027]      FIG. 6  is a cross-sectional view of the object depicted in  FIG. 5B  along the broken lines marked  FIG. 6  showing a quick-change finger mechanism fully engaged; 
           [0028]      FIG. 7  is a side-perspective view of the locking lever fully engaged with the rear pillar head of the present invention; 
           [0029]      FIG. 8  is a side view showing the details of engagement in the quick-change assembly of the present invention; 
           [0030]      FIG. 9A  is a top-perspective view of the quick-change assembly of the present invention; 
           [0031]      FIG. 9B  is a sectional view of the object depicted in  FIG. 9A  taken along broken lines labeled A with the arrows indicating the direction of sight of the present invention; 
           [0032]      FIG. 10A  is a top-perspective view of the quick-change assembly of the present invention; 
           [0033]      FIG. 10B  is a sectional view of the object depicted in  FIG. 10A  taken along broken lines labeled A with the arrows indicating the direction of sight of the present invention; 
           [0034]      FIG. 11A  is a top-perspective view of the quick-change assembly of the present invention; 
           [0035]      FIG. 11B  is a sectional view of the object depicted in  FIG. 11A  taken along broken lines labeled A with the arrows indicating the direction of sight of the present invention; 
           [0036]      FIG. 12  is a top-perspective view of an alternative finger arrangement exhibiting multiple gripper and assembly combination; and 
           [0037]      FIG. 13  is a flow diagram showing method steps in accordance with the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0038]    An object of the present invention is to provide a quick-change assembly for changing tools, specifically a finger, to a robotic manipulator. The quick-change assembly can facilitate tool replacement as the tasks that the robot is needed to perform changes. The quick-change assembly can be used to attach any finger adapted to use the assembly to a gripper, where the gripper is attached to a robot arm. In addition, the quick-change mechanism can be used to attach different types of fingers, as required by a particular task, including different sizes, including long, short, thin, or wide fingers, fingers having specialized surfaces, fingers made from various materials, and fingers with shapes as required for a different job, such as a straight or arched-shaped finger. Types of tools that one skilled in the art could envision using with the present invention include an arm linkage, an arm segment, an arm extender, a gripper, a gimble grip, a flexible joint, a tilt table, a dozer, a shovel, a plow, a pan-tilt table, a digger, a sensor, a disruptor, a drill, a saw, a cutter, a grinder, a digging tool, or a camera. A further object of the invention is the manual operability of the assembly. The quick-change assembly facilitates the rapid change of the finger from the robot by providing a mechanism manual operable, therefore, no external tool is needed to detach and engage the robot tool. The quick-change assembly can also be adapted to provide multiple quick-change assemblies in a tool for load balancing or adapting certain types of fingers and certain types of grippers. 
         [0039]    With reference to  FIG. 1 , a quick-change mechanism  2 , having a gripper mechanism defined as a gripper  6  and a tool member defined as a finger member  4 , is shown mated but not engaged. Gripper  6  can include gripper arms  8  and  9 . The gripper arms  8  and  9 , having a cylindrical bar defined as the gripper bar  10  therebetween, securing arm  8  to arm  9 . The gripper bar  10  can be connected to the arms  8  and  9  by passing threaded ends (not shown) of the gripper bar  10  through a hole in gripper arms  8  and  9 , and connecting to each end of the gripper bar  10  with a bolt defined as head  12  threadably connected. It will be recognized by one of skill in the art that other types of coupling mechanics can be used to connect the bar to the arms  8  and  9  while still providing head  12 . Each gripper arm  8  and  9  can also include, at one end, a semi-circular cavity  14  and  18 . The circular cavities  14  and  18  are symmetrical and share the same axis. Cavity  14  includes lips  16 A and  16 B. The edges of lips  16 A and  16 B can be chamfered to facilitate the engagement of finger  4 . Likewise, cavity  18  includes a symmetrical set of lips  20 A and  20 B having chamfered edges. Gripper  6  can have, at a distal end, an attachment mechanism in one embodiment the attachment mechanism can be defined by a hole  19 , bearing  20 , attachment hole  22 , and attachment member  24 . The attachment mechanism can be used to connect the quick-change mechanism to a robot. One skilled in the art could recognize that other attachment mechanisms for attaching a quick-change mechanism to a robot are possible and variable, depending on the available robotic manipulator. Although aluminum is used in the preferred embodiment, other types of materials can be used to achieve strength or to affect weight. These materials include steel, titanium, stainless steel, brass, carbon composite, acetal resin, fiber glass composite, polyethelyne, or plastic. 
         [0040]    With continued reference to  FIG. 1 , the tool member can be defined as a finger member  4  having a finger body  30  and a finger  32 . The finger body  30 , shown in  FIG. 1 , is one type of finger that can be used with the present invention as one skilled in the art could recognize that other types of fingers would be adaptable to the quick-change mechanism of the present invention, as previously discussed. The finger body  30  can have a semi-circular cavity forming a longitudinal passageway  34  along the length of the cavity through the proximate end of the finger body  30 . The passageway  34  can have members defined as a first lip  36 A and second lip  36 B, similarly formed along the length of the passageway  34 . The lips  36 A and  36 B can be adapted to mate with the cylindrical gripper bar  10 . In addition, finger body  30  can have a locking bar  37  and a locking lever  38 . The locking bar  37  can extend through a passage  40  formed in the finger body  30 . 
         [0041]      FIG. 2  shows the finger member  4  and gripper member  6  of the present invention in an engaged position. As shown, the quick-change mechanism  2  having finger  4  mated with the gripper  6  is shown, with the gripper bar  10  displaced into the passageway  34  and the cavities  14  and  18  of gripper  6  mating locking bar  37  of finger body  30 . The locking lever  38  is open and not engaged; therefore, the finger  4  is removable from the gripper  6 . 
         [0042]    With reference to  FIG. 3 , the locking bar  37  of the quick-change mechanism  2  is shown in detail having a pin  42  and a sleeve  44 , the pin  42  having a flanged surface  47  and sleeve  44  having a flanged surface  48 . The flanged surfaces  47  and  48  can mate with respective recessed surfaces  46  and  50  in the gripper arms  8  and  9  when the quick-change mechanism  2  is engaged, thereby keeping the finger  4  tightly connected to the gripper  6 . A feature of the present invention can be the interchangeability of the parts as the orientation of the finger member  4  with gripper  6  is not limiting. In other words, the gripper  6  can mate with an upward or downward facing finger  4 . 
         [0043]    With continuing reference to  FIG. 3 , when the pin  42  and sleeve  44  are mated, a threaded surface  53  on pin  42  can be received by a threaded surface  52  on an axial bore  80  of the sleeve  44 . The pin  42  is connected to the sleeve  44  by rotating the pin  42  and causing threaded surfaces of the sleeve  44  and pin  42  to threadably connect. Rotation of the pin  42  is caused by turning the locking lever  38 . The engaged length of the sleeve  44  and pin  42  to form locking bar  37  decreases as it rotates and causes the flange surfaces  47  and  48  to move into engagement with the recesses  46  and  50 . The pin  42  can have a slotted surface  54  to limit vertical movement of the pin  42  within the finger  4 . The slotted surface  54  is an area of pin  42  recessed radially into the pin  42  to form a circumferential cavity surrounding the pin  42 . The slotted surface  54  can extend entirely about the circumference of the quick-change pin  42 . The shape of the slotted surface  54  can be varied to cause different behaviors, for example, the recess could also be formed of a partially, circumferential slot thereby, limiting both vertical and horizontal movement of said pin  42 . 
         [0044]    The quick-change mechanism  2  can have a member displaced therein, which can stop the quick-change pin  42  from moving vertically while forcing the vertical movement of the sleeve  44 . In one embodiment, a threaded member, defined as pilot screw  56 , is received by a threaded cavity  56 ′ formed in the finger body  30  of finger  4  and further received by aligned slotted surface  54  of pin  42 . The pilot screw  56  can be used to force the movement of the sleeve  44  perpendicular to the finger body  30  by limiting the quick-change pin  42  from moving perpendicular to the finger body  30  and gripper arms  8  and  9  when the pilot screw  56  is adjacent the walls formed by the slotted surface  54 . Pin  42  is rotated into the quick-change sleeve  44 . The pilot screw  56  is adjacent a recessed area  50  of the pin  42  and when the lever  38  is rotated, it causes the threadable connection to force the sleeve  44  to move vertically, perpendicular to finger body  30 . In this way, the flange  48  of sleeve  44  is mated or unmated from recess  50  in gripper arm  9 . 
         [0045]    The sleeve  44  includes two slotted surfaces  62  and  64 . These slotted surfaces  62  and  64  can limit movement of horizontal rotation. The slotted surfaces  62  and  64  are rectangular openings formed by a slot extending radially through the sleeve  44 . The openings are symmetrically formed on each side of the axial bore  80  of sleeve  44 . 
         [0046]    For limiting sleeve rotation, roll pin  58  can be used by the quick-change mechanism  2 . The roll pin  58  can limit rotation of the sleeve  44  as a threaded pin  42  is displaced therein. The effect of this roll pin  58  is to force the threading rotational movement of sleeve  44  and pin  42  to engage the sleeve  44  by displacement into the sleeve  44  and reduce slipping. The roll pin  58  is positioned in the gripper  6  through cavity  60 A aligned through the slotted surfaces  62  and  64  of sleeve  44  and the aligned cavity  60 B. Roll pin  58  is therefore positioned to counteract any rotational force on sleeve  44 . In other embodiments, sleeve  44  can have a slightly different slotted surface, the roll pin  58  can be used to stop the sleeve  44  from moving perpendicular to the gripper arms  8  and  9 , and finger body  30  by limiting vertical travel of the sleeve  44 , as previously discussed. A wall  66   a  or  60   b  defined by a slotted surface can be used to limit vertical movement of the sleeve  44 . 
         [0047]    The roll pin  58  limits vertical movement of the threaded sleeve  44  only. The pilot screw  56  limits vertical movement of the quick-change pin  42 . In the case where the assembly  2  is locked onto the gripper arms  8  and  9  and the assembly experiences binding due to corrosion, debris, damage, or wear, this feature can help to disengage. As the user turns the locking lever  38  counter clockwise and overcomes the binding, the sleeve  44  and the pin  42  un-thread from each other and the overall length increases. If the roll pin  58  is in place but pilot screw  56  is not used, it is likely that only the top  47  or bottom flange  48  would unseat from the gripper arms  8  and  9 , and the user would probably need to hammer the post assembly to free the other flanges. In addition, the pilot screw  56  can keep the user from completely unscrewing the pin  42  by keeping it captive. 
         [0048]    With the roll pin and pilot screw, as the user unscrews the locking lever, the roll pin will limit travel in one direction and the pilot screw limit it in the other direction. Each flange will be forced out to the position that clears the gripper arms, regardless of which side breaks loose first. 
         [0049]    As shown in  FIG. 3 , additional holes  68 A and  68 B are provided to adapt the finger body  30  to an upward or downward facing finger orientation as needed in the implementation of the present invention. The locking lever  38  is attached to pin  42  by a member defined as pin  72  as positioned through the center of lever  38  and pin  42  and can hold the locking lever  38  to the quick-change pin  42 , forcing the quick-change pin  42  to rotate as the locking lever  38  is turned clockwise or counterclockwise. 
         [0050]    With reference to  FIGS. 4B and 4C , the engagement motion of the quick-change mechanism  2  is shown. In  FIG. 4A , finger  4  and gripper  6  are disengaged, however, a motion A and B is moving the finger member  4  and gripper  6  together. With reference to  FIG. 4B , in phantom, the finger body  30  of finger member  4  is shown almost engaging gripper bar  10  of the gripper  6 . Finally, with reference to  FIG. 4C , the movement is complete, the gripper bar  10  of the gripper  6  is fully mated with the passageway  34  of finger body  30  of finger member  4 , and the quick-change mechanism  2  is ready to be engaged. 
         [0051]    With reference to  FIG. 5A , finger  4  is shown engaged with the gripper  6  and the locking lever  38  has been rotated as seen in  FIG. 5A  and the flanged surfaces  47 ,  48  ( 48  not shown in  FIG. 5A ) are displaced into the recessed area  46  and  50  ( 50  not shown in  FIG. 5A ) of the gripper arms  8  and  9 , respectfully. The pin  42  can be seen displaced into gripper  6 , see  FIG. 5A . As distinguished from the pin  42  in  FIG. 2 , where the flange surfaces  47  and  48  are shown extending outward from the gripper arms  8  and  9 , indicating the locking lever  38  has not been rotated. The position of the flanged surfaces  47  and  48  in  FIG. 5A  indicates that the locking lever  38  has been rotated and the pin  42  has mated with the sleeve  44 . With reference to  FIG. 5B , a fully closed locking lever  38  is fully engaged. Locking lever  38  is mated to head  12 , locked thereon. 
         [0052]    With reference to  FIG. 6 , the closed locking bar  37  and locking lever  38  are distinguished from the open locking bar  37  and locking lever  38 , shown in  FIG. 3 . 
         [0053]    With reference to  FIG. 7 , the locking bar  37  is shown in phantom with the member parts shown therein. Locking bar  38  can have a retaining pin  76 . The retaining pin  76  engaged a slotted surface  78  in the head  12  of the gripper bar  10 . 
         [0054]    With reference to  FIG. 8 , a transition of the degree of freedom can be restrained vertically, horizontally, and rotational about the axis. The finger body  30  is restricted from moving when attached to the gripper  6 . The finger body  30  cannot move in the plan as shown by Arrow  80  and  82  and, in addition, is restrained from moving rotationally about the axis normal to the view. In addition, the surfaces  16 A and  16 B are shown providing alignment of the finger  4  during engagement with the gripper  6 , first lip  36 A and second lip  36 B sliding smoothly onto gripper bar  10  of gripper  6 . 
         [0055]    With reference to  FIG. 9A , a finger member  100  opened and ready to engage with a gripper is shown. One of the advantages of the present invention is the ability to interchange fingers and grippers. This ability to connect to different grippers presents a problem because the grippers can all have slightly different deviations. The deviations can be caused during manufacturing. For example, one design of a gripper can have arms with a specified thickness, where the thickness is required to be, for example within a 5,000 th  of an inch, which can present unaccounted for variability of thickness range for the grippers manufactured. In other cases, debris, dirt and wear, can change the gripper over time. Therefore, manufacturing deviation or even wear and tear can account for slight deviations in the thickness of the gripper. 
         [0056]    Deviations in gripper arm thickness can have dramatic effect on the quick-change assembly. In order to overcome these deviations, in an embodiment shown in  FIG. 9B , the bar  102  of finger member  100  can have a spring, defined as a washer  104 , in one embodiment a Belleville washer, to provide more compliance in the locking bar  102  when engaging the device with the locking lever  106 . Locking bar  102  can have a pin  108 , a sleeve  110 , and a connector  112 . The connector  112  is positioned between the pin  108  and sleeve  110  and has an axial bore  114  having a threaded first end  116  and a threaded second end  118 . In addition the connector  112  can have a first wall  120  and a slotted surface  122  formed of symmetrical rectangular slots formed in the connector  112  defining a top and bottom wall  124  and  126  and side wall  122   a  and  122   b  (not shown). 
         [0057]    With continuing reference to  FIG. 9B , a threaded shoulder bolt  128  receives the spring  104  and then is received by the sleeve  110 . The threaded end  130  of the shoulder bolt  128  is then threadably connected to the threaded first end  116  of the connector  112 , as the bolt  128  is tightened, the shoulder  132  a resisting force is received from wall  120  of the connector  112 . Further tightening of the bolt  128  causes the resistance of the washer  104  as compression is initiated between the surface  136  of shoulder bolt  128  and flanged surface  138 . The threaded end  134  of pin  102  is received by the threaded second end  118 . 
         [0058]    With reference to  FIG. 10A , finger member  100  is shown opened and mated with a gripper  140 . The gripper  140  having arms  142  and  144 . In  FIG. 10B , a cross section as previously described with regards to  FIG. 9B , with like numbers for like parts is shown. The gripper arm  140  is mated with sleeve  110  and gripper arm  144  is mated with pin  108 . The flanges  150  and  152  are aligned with the recessed areas of the gripper arms  154  and  156 . The washer  104  remains primarily uncompressed. 
         [0059]    With reference to  FIG. 11A , finger member  100  is shown opened and mated with a gripper  140 . The gripper  140  having arms  142  and  144 . In  FIG. 10B , a cross section as previously described with regards to  FIG. 9B , with like numbers for like parts is shown. 
         [0060]    The finger member  100  and gripper  140  are mated and engagement begins with rotation of the locking lever  106  clockwise about the axis. As rotation begins, the locking lever  106  turns the pin  108 . As the pin  108  is rotated, threaded members  134  along the outside surface are threadably connected to threads  118  along the inner surface of connector  112 . The threaded connection can cause connector  112  to rotate coincident with pin  108 . As the connector rotates, it hits a roll pin  160  positioned between a slotted surface  122 A and  122 B which causes the sleeve to stop rotation. The pin  108  is then threaded into the connector  112 . As it is threaded, the pin  108  is displaced vertically into finger member  100 , with flanged surface  152  mating  156 . Further rotation, rotates the mated pin  108  and connector  112 , pulling the connector  112  and sleeve  110  connected to the sleeve by the shoulder bolt  128  until the slotted surface  126  of connector  112  hits the retaining pin  160  which blocks further vertical movement of connector  112 . As rotation continues, the pin  108  now finally finishes entering the connector and the flanged surface  152  mates entirely with recess  144 . After the sleeve  110  and pin  108  are fully engaged, or bottomed out, the washer  104  gives the lever more compliance. Therefore, the lever  106  can be further turned which causes the recessed surface  154  to resist the flanged surface  150 . This resistance in turn  108  to pull the connector  112  which in turn pulls the shoulder bolt  128 . As the bolt  128  is pulled, it causes the washer  104  to be compressed between the surface  136  of bolt  128  and the surface  138  of sleeve  110 . This compression in the washer  104  can cause a gap  170  between the connector  112  and first wall  120  of the sleeve  110 . This gap is the space equal to the compliance in the washer  104  and equates to extra torque in the locking lever  106 . The extra torque  106  gives the lever rotational free play in order to turn the lever enough to lock the assembly and also mate the locking lever  106  with the head of the pillar. When turning the lever  106 , the bottoming out at the washer means that there is always enough torque to get at least another turn of the lever  106 . Without the washer, the lever is one for one rotation. In another embodiment, the lever can be altered to give additional free play. By changing the pin connecting the lever to the locking bar, an additional 180 degrees of free play can be attained. When disengaging, first the lever will swing and additional 180 degrees and then the rotation of the locking bar will start. 
         [0061]    With reference to  FIG. 12 , a quick-change assembly adapted to provide multiple quick-change assemblies in a tool for load balancing or adapting certain types of fingers and certain types of grippers. A parallel gripper  180  is shown having multiple fingers  182  and  184 . 
         [0062]    With reference to  FIG. 13 , a method of changing a finger assembly begins with block  200 . At conditional block  202 , if the quick-change mechanism  2  is engaged, then process flows to block  204 , otherwise, the quick-change mechanism  2  is disengaged at block  206 . At block  204  the finger member  4  is removed from the gripper  6 , gripper  6  already attached to a robot is ready for a new finger member  4 , process flows to block  200 , to begin installation of the finger member  2 . At block  206 , a new finger member  4  is provided. Next, the provided finger member  4  is placed adjacent gripper  6  and aligned at block  208 . At block  210 , the finger member  4  is moved toward gripper  6 . With the movement, finger member  4  is displaced into a mated position with the gripper  6  at block  212 . In mated position, the gripper bar  10  of gripper  6  is received by passageway  34  of finger body  30  and the locking bar  37  is received by circular cavities  14  and  18 . Mating of the finger body  30  to the gripper arms  8  and  9  is eased and guided by the rounded edges of the lips  16 A and  16 B of circular cavity  14  and the rounded edges of the surfaces  20 A and  20 B of cavity  18 . Likewise, the smoothed lips  36 A and  36 B of passageway  34 , guide and facilitate the mating with the gripper bar  10 . 
         [0063]    At conditional block  214 , the finger member  4  and gripper  6  are mated and engagement begins with rotation of the locking lever  38  clockwise about the axis of locking bar  37 . The direction is a function of the threads inside the assembly and is not meant to be limiting. As rotation begins, the locking lever  38  turns the quick-change pin  42  at block  216 . As the quick-change pin  42  is rotated, threaded members along the outside surface are threadably connected to threads along the inner surface of sleeve  44  at block  218 . The threaded connection causes sleeve  44  to rotate with pin  42  at block  220 . As the sleeve  44  rotates, it hits a roll pin  58  lodged between a first and second slotted surface  62  and  64  which causes the sleeve to stop rotation. The pin  42  is pulled toward the sleeve  44 . The pin  42  is displaced vertically into the passage  40  through the finger member  4  until it hits the upper wall of slotted surface  54  which blocks further vertical movement of pin  42  at block  226 . As rotation continues, the pin  42  rotating around sleeve  44  now pulls the sleeve  44  into passage  40  at block  228 . As the sleeve is pulled, the flanged surfaces  47  and  48  are pulled into recesses  46  and  50  in arms  8  and  9  at block  228 . The locking lever  38  is rotated until a spring  90  between flange surface  48  and recess  50  is compressed and the locking lever  38  rotation is limited and tight. Also the locking lever  38  is rotationally adjusted in order to make the locking lever  38  align with the head  12  of the gripping bar  10 . A spring can be alternately used to accord free play in the lever when adjusting. At block  234 , the locking lever  38  is closed, by positioning the locking lever  38  onto the head  12  until the locking pin  42  therein locks on a grooved surface of the head  12 . 
         [0064]    To remove, the locking lever  38  is lifted from head  12 . Locking lever  38  is rotated about the axis of locking bar  37  in a counterclockwise direction. The pin  42  is displaced from the sleeve  44  causing flanged surface  47  to exit the recess  50  until the pin  42  reaches a wall of the slotted surface  54 . Then, the sleeve  44  is pushed outward from the passage  40  of finger body  30 . The flanged surfaces  47  and  48  at both ends of locking bar  37  are moved outward from the gripper arms  8  and  9 . The finger member  4  is displaced from the gripper  6 . 
         [0065]    These and other features and characteristics of the present invention, as well as the methods of operation and functions of the related elements of structures and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. As used in the specification and the claims, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.