Patent Publication Number: US-2020289899-A1

Title: Apparatus and method for stringing a lacrosse head

Description:
RELATED APPLICATION 
     This application claims the benefit under 35 U.S.C. § 119(e) to U.S. Provisional Application Ser. No. 62/597,166, entitled “APPARATUS AND METHOD FOR STRINGING A LACROSSE HEAD”, filed on Dec. 11, 2017, which is hereby incorporated by reference in its entirety. 
    
    
     FIELD 
     The present disclosure relates generally to automated methods and apparatus for stringing lacrosse heads, and more specifically to stringing a lacrosse head with at least one robotic arm. 
     DISCUSSION OF RELATED ART 
     Stringing a lacrosse head by hand requires experience and can take approximately thirty minutes. Players are often hesitant to have their lacrosse heads re-strung when a pocket nears its end of usable life because the new pocket may vary from the current pocket unless strung by the same person in the same manner. 
     SUMMARY 
     According to one embodiment, a lacrosse head stringing system includes a first robotic arm having a first gripper, a second robotic arm having an end effector, and a controller including a set of instructions configured to control the first gripper and the end effector to manipulate one or more strings to form a lacrosse pocket that is attached to a lacrosse head. 
     According to another embodiment, a method of stringing a lacrosse head using a robotic manipulator is provided. The robotic manipulator comprising a first end effector configured to manipulate a first string portion, and a second end effector configured to manipulate a second string portion. The method includes controlling the first end effector to manipulate a first string portion through a first opening in a sidewall of the lacrosse head, controlling the second end effector to pull a second string portion away from the sidewall to form an opening between the second string portion and the sidewall, and controlling the first end effector to manipulate the first string portion through the opening between the second string portion and the sidewall. 
     According to a further embodiment, a method of attaching a mesh pocket to a lacrosse head using a robotic manipulator is provided. The robotic manipulator includes an end effector and a first gripper, the first gripper being configured to grip and manipulate a first portion of a string. The method includes controlling the first gripper to manipulate a first string portion through a first opening in a sidewall of the lacrosse head, and through a first opening in the mesh pocket. The method also includes controlling the end effector to separate a portion of a perimeter of the first mesh pocket opening from a second portion of the string. Further acts include controlling the first gripper to manipulate the first string portion between the portion of the perimeter of the first mesh pocket opening and the second portion of the string gripper, and controlling the first gripper to manipulate the first string portion through a second opening the sidewall of the lacrosse head. 
     In another embodiment, an apparatus includes a lacrosse head having a first sidewall and an opposite second sidewall, a pocket attached to the lacrosse head with a plurality of strings which pass through sidewall openings, and a first string of the plurality of strings, the first string extending inwardly from a first sidewall opening on the first sidewall. The apparatus also includes a second string extending inwardly from a second sidewall opening on the second, opposite sidewall, the second sidewall opening being directly opposite the first sidewall opening. The first and second string have the same applied tension when the pocket is in a resting state. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Aspects of the invention are described below, by way of example, with reference to the accompanying drawings in which like numerals reference like elements, and wherein: 
         FIG. 1  is a front view of a lacrosse head strung using embodiments disclosed herein; 
         FIG. 2  is a front view of a mesh pocket which has been attached to a lacrosse head using embodiments disclosed herein; 
         FIG. 3  shows one embodiment of a robotic arm system according to one embodiment; and 
         FIG. 4  is a kinematic diagram of a dual robotic arm system according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     It should be understood that aspects of the invention are described herein with reference to certain illustrative embodiments and the figures. The illustrative embodiments described herein are not necessarily intended to show all aspects of the invention, but rather are used to describe a few illustrative embodiments. Thus, aspects of the invention are not intended to be construed narrowly in view of the illustrative embodiments. In addition, it should be understood that aspects of the invention may be used alone or in any suitable combination with other aspects of the invention. 
     Lacrosse players become accustomed to the shape and feel of their lacrosse head pocket, and replacing the pocket can change the shape and feel because a new pocket is not as broken-in as the pocket being replaced. Additionally, the new pocket may not be strung in the same manner as the old pocket, further altering the feel of the pocket. In an attempt to maintain as much consistency as possible, the player may have the same person string the new pocket, though restricting the stringing to a single person may cause scheduling difficulties. 
     Even if the same person strings the new pocket and uses the same materials as the old pocket, there can be variation in the results because many aspects factor into the final pocket configuration. For example, the distances between knots, the force applied when tying each knot, and/or the tension in the strings connecting the pocket to the head may play a role in the final pocket configuration. Additionally, explaining particular desires to a stringer with the necessary level of precision can be difficult, and a stringer may have difficulty remembering how a pocket was previously strung for a given person. 
     When manufacturing a new pocket and/or attaching a pocket to a lacrosse head, consistency from pocket-to-pocket can be important. For example, if a particular line of lacrosse heads has three different models, each with a different level of pocket tension, controlling the amount of tension in each of the models to within certain tight tolerances may be important. Additionally, controlling tension and/or string lengths within a single pocket may be important for producing a strung lacrosse head that is tuned in a desired manner. For example, it may be desirable to produce a head/pocket combination that is symmetric about a longitudinal axis of the head. Or, for some lacrosse heads, an asymmetry in the tension of certain areas of the pocket may be desired, and the desired tensions are achievable to within certain limits by using a robotic manipulator. 
     According to the present disclosure, by using a robotic manipulator, such as robotic arms, the forces and angles applied on the strings during stringing of a lacrosse head may be controlled, and precise string lengths may be implemented for certain features of the pocket. In some embodiments, the manipulator attaches the pocket to a lacrosse head and produces a strung head which has precise ratios of tension when comparing various strings within the pocket. The forces used when tying each knot can be consistent throughout the pocket, or vary according to which particular knot is being tied. The tension of shooting strings and/or runners may be finely tuned in some embodiments. 
     Turning to the figures,  FIG. 1  shows a traditionally-strung conventional lacrosse head  102  including a pocket  100  comprising longitudinal runners  101 , cross-lacing  104 , and shooting strings  106 . The longitudinal runners  101  are attached to openings  108  in a scoop end  110  of the head  100 , and also to openings (not shown in  FIG. 1 ) at a ball stop end  114 . Sidewalls  116  of the head  100  include openings (not shown in  FIG. 1 ) which are used to secure the cross-lacing  104  and the shooting strings  106  to the head  100 . The runners  102  may be formed with leather or any other suitable material. 
     According to the present disclosure, some or all of the cross-lacing  104 , longitudinal runners  101 , and shooting strings  106  may be interwoven by a programmed mechanical manipulator such as one or more robotic arms. 
       FIG. 2  shows a mesh pocket  200  attached to a lacrosse head  202 . The mesh includes strands  204  which intersect at nodes  212 . The mesh material typically includes fibers made of one or more of nylon, polyester, and composite materials. The mesh is attached to sidewalls  216  of the head, a scoop end  210  of the head, and a ball stop end  214  of the head. Shooting strings  206  may be woven through the mesh. According to embodiments disclosed herein, the attachment of the mesh pocket  200  to the sidewalls  216  may be achieved using one or more robotic arms. In some embodiments, the shooting strings  206  may be woven using robotic arms. 
       FIG. 3  shows a robotic arm  300  with an end effector  301  having a hollow needle  302  through which a string  304  may be fed. The needle  302  pushes or pulls the string  304  to loop the string around another string being manipulated by a second robotic arm. The needle  302  also may be used to push the string  304  through an opening in a lacrosse head  308 . A second hollow needle  312  and a second string  314  may be manipulated by a second robotic arm (not shown). Once the first needle  308  is through the opening, the second needle may be inserted between the first string and the needle such that when the first needle is retracted through the opening, the second string is captured in a loop  316  formed by the first string. Similar manipulations may be operated around the sidewall and/or scoop of the lacrosse head  308  to attached the pocket to the head. 
     Needles other than hollow needles may be used in some embodiments. For example, in some embodiments, a needle sidewall or other instrument may be used to push a string portion. The needle may be moved along its length next to and perpendicular to a string, and then moved sideways such that the needle sidewall pushes the string. 
     In the illustrated embodiment, robotic arm  300  is formed of six revolute joints which form a first rotation axis A, a second rotation axis B, a third rotation axis C, a fourth rotation axis D, a fifth rotation axis E, and a sixth rotation axis F. This arrangement allows first needle  302  to reach any location within a working envelope. Programmed manipulators having five degrees of freedom may be used in some embodiments, and programmed manipulators having six degrees of freedom may be used in some embodiments. Additional, redundant axes of rotation may be added to allow the robotic arm to achieve a given position using more than one set of revolute joint rotations. Fewer degrees of freedom may be used by certain components in some embodiments. For example, a needle may be operated to move only forward and backward while a lacrosse head is progressively moved to position various openings to align with the needle. 
     A controller  322  is connected to robotic arm  300  and any other robotic arms in some embodiments. The controller receives instructions for operating the robotic arm(s) to string lacrosse heads. The controller may include a single, dedicated set of instructions such that the system repeatedly strings lacrosse heads in the same manner. Or, in other embodiments, the controller may receive multiple different sets of instructions such that the system strings the same type of lacrosse head in different manner, or strings different types of lacrosse heads. 
     The end effector of one or both robotic arms may include an instrument other than a hollow needle. One or more clamping grippers may be provided in some embodiments. Various interchangeable end effector instruments may be provided, and the robotic manipulators may change end effector instruments during or between head stringing. The change of end effector instruments may be performed automatically or manually. 
     Kinematic chains which are different than the illustrated embodiment may be used in methods and robot configurations that string lacrosse head pockets. Various arrangements of hinged joints and sliding joints may be used. 
       FIG. 4  is a kinematic diagram of one example of first and second robotic arms  400 ,  402  which may be used to string a lacrosse head. Each cylinder represents a revolute joint. Each arm  400 ,  402  may be a five-axis, six-axis, or seven-axis arm in various embodiments. In some embodiments, an ABB dual arm YuMi® robot may be used to string a lacrosse head. The robotic arms may include grippers  404 ,  406  for end effectors in some embodiments. The grippers may resemble needle-nose pliers in some embodiments. 
     In some embodiments, a controller  408  is programmed to control the first gripper  404  to grip a first string portion near an end of the string, and manipulate the string through a series of loops and knots. The second gripper  406  is controlled to progressively grip other portions of the same string to form loops (or other shapes) through which the first gripper  404  moves the first string portion. 
     For example, in one embodiment, the first gripper pushes a first end of a string through a first opening in a lacrosse head sidewall from the outside of the sidewall to the inside of the sidewall, releases the string, and then re-grips the string on the inside of the sidewall. The first gripper pulls the string all the way through the sidewall opening until a knotted end abuts an exterior of the sidewall. The first gripper then passes the string end through an opening in a lacrosse pocket (such as a mesh pocket) and then around a bottom side of the sidewall, and pushes the first string end through a second sidewall opening from the outside to the inside. At this point, the second gripper grips the string portion that is abutting the bottom of the sidewall and pulls the string portion away from the sidewall to form the space between the string of the sidewall. The first gripper then passes the first string end through the space and pulls the remainder of the string through the loop. The first gripper then brings the first end to a third sidewall opening and repeats the process. In this manner, the first and second robotic arms  400 ,  402  may attach a previously-formed pocket to a lacrosse head. 
     In some embodiments the first and second grippers may be controlled to form the pocket itself by interweaving one or more strings in a programmed pattern. For example, one or more strings may be looped through openings extending from pre-formed runners. Or, a first string may be interwoven with a second string to from a complete pocket, and runners and/or shooting strings may be added manually or by using the robotic arms. In some embodiments, a single string is woven using the first and second grippers to form a pocket. The strings may include aglets or hardened ends to facilitate movement through openings. According to some embodiments, a third robotic arm (not shown) may be used to hold and reorient the lacrosse head. 
     Precise and repeatable forces may be applied to the strings by the robotic manipulators during pocket manufacture such that the resulting pocket has prescribed tension in certain areas of the pocket, with the tensions falling within a small tolerance range. Similarly, lengths of the string between knots between knots, loops, openings, etc. may be precisely controlled according to some embodiments herein. For example, within a given strung lacrosse head, various string lengths which are supposed to be of similar length may vary from each other by less than 1% in some embodiments. In some embodiments, the direction of force applied to the string by the gripper or other end effector may be precisely controlled to produce repeatable results. 
     In a similar manner, systems described herein may produce strung lacrosse heads which have consistent pocket shapes and tensions from head-to-head. 
     Custom pockets may be strung according to embodiments disclosed herein. For example, a standard set of stringing instructions may be provided for a given type of lacrosse head, and modifications to the instructions may be made based on user input. A user may provide input regarding pocket location, string tension, string color, and other parameters. An algorithm then may modify the set of instructions sent to the controller. 
     Spools of string to be used to string the pocket may be provided, and the robotic arms may be controlled to select one or more spools during pocket stringing. In some embodiments, a user may select which color or colors to be used to string the pocket. Examples of materials that may be used for stringing a lacrosse that include nylon, polyester, polyethylene, cotton, and any other suitable material. 
     The systems and methods described herein may be used to string goalie sticks as well. 
     For purposes of this patent application and any patent issuing thereon, the indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.” The phrase “and/or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and/or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified. 
     The use of “including,” “comprising,” “having,” “containing,” “involving,” and/or variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. 
     It should also be understood that, unless clearly indicated to the contrary, in any methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited. 
     The foregoing description of various embodiments are intended merely to be illustrative thereof and that other embodiments, modifications, and equivalents are within the scope of the invention recited in the claims appended hereto.