Patent Publication Number: US-10780558-B2

Title: Tool extensions

Description:
TECHNICAL FIELD 
     The present disclosure relates, generally, to tool extensions and, more particularly, to tool extensions including an electro-rheological (ER) fluid configured to alter the rigidity of the tool extension. 
     BACKGROUND 
     Many tools that are used for tightening and loosening fasteners may be difficult to fit into tight spaces. In particular, power tools and larger manually-operated tools may not be able to reach certain fasteners due to the size, length, and/or orientation of the tool head and the output drive. Tool extensions, which may more easily fit in some tight spaces, are sometimes used to transfer rotational torque from such tools to hard-to-reach fasteners. However, existing tool extensions typically have limited use, due in part to the fixed rigidity of these tool extensions. 
     SUMMARY 
     According to one aspect, a tool extension may comprise a drive core and a shell surrounding the drive core. The drive core may be configured to transfer rotational torque from a first end to a second end opposite the first end, where the first end is configured to be removably coupled to a tool to receive rotational torque from the tool, the second end is configured to be removably coupled to a fastener to supply rotational torque to the fastener, and the drive core is bendable between the first and second ends. The shell may contain an ER fluid configured to transition between a flexible state in which the shell permits bending of the drive core and a rigid state in which the shell resists bending of the drive core. 
     In some embodiments, the tool extension may further comprise one or more electrodes configured to selectively apply an electric field to the ER fluid to cause the ER fluid to transition from the flexible state to the rigid state. The tool extension may further comprise a power source coupled to the shell near the first end of the drive core. The power source may be configured to selectively supply an electric current to the one or more electrodes. 
     In some embodiments, the tool extension may further comprise one or more actuators configured to selectively apply a compressive force to the ER fluid to cause the ER fluid to transition from the flexible state to the rigid state. The one or more actuators may be configured to selectively apply the compressive force to the ER fluid by altering an internal volume of the shell containing the ER fluid. The shell may comprise an inner shell contacting the drive core and an outer shell surrounding the inner shell. The ER fluid may be disposed within an annular space between the inner and outer shells. The shell may further comprise a first end plate joining the inner and outer shells at the first end of the drive core and a second end plate joining the inner and outer shells at the second end of the drive core. One or both of the first and second end plates may comprise an electrode configured to selectively apply an electric field to the ER fluid to cause the ER fluid to transition from the flexible state to the rigid state. 
     In some embodiments, the second end of the drive core may be movable in three dimensions relative to the first end of the drive core when the ER fluid is in the flexible state. In some embodiments, the shell may be configured, when the ER fluid is in the rigid state, to apply a normal force to the drive core that promotes the transfer rotational torque from the first end of the drive core to the second end of the drive core. The second end of the drive core may be configured to be removably coupled to one of a plurality of differently sized tool elements to supply rotational torque to the fastener. 
     According to another aspect, a tool extension may comprise an inner shell, a drive core positioned in the inner shell, an outer shell surrounding the inner shell with a space therebetween, and an ER fluid disposed between the inner and outer shells. The drive core may be configured to rotate within the inner shell to transfer rotational torque from a first end of the drive core to a second end of the drive core. The drive core may be bendable between the first and second ends. The ER fluid may be disposed in the space between the inner and outer shells and may be configured to increase rigidity in the presence of an electric field to resist bending of the drive core. 
     In some embodiments, the first end of the drive core may be configured to be removably coupled to a tool to receive rotational torque from the tool. The second end of the drive core may be configured to be removably coupled to a fastener to supply rotational torque to the fastener. The tool extension may further comprise a first end plate joining the inner and outer shells at the first end of the drive core and a second end plate joining the inner and outer shells at the second end of the drive core. One of both of the first and second end plates may comprise an actuator configured to selectively apply a compressive force to the ER fluid to further increase the rigidity of the ER fluid. 
     According to yet another aspect, a method of using a tool extension may comprise coupling a first end of a drive core of the tool extension to a tool, where the drive core is surrounded by a shell containing an ER fluid, coupling a second end of the drive core to a fastener, bending the drive core into a desired geometric configuration, rigidizing the ER fluid of the tool extension to maintain the drive core in the desired geometric configuration, and operating the tool, after rigidizing the ER fluid, to provide rotational torque to the first end of the drive core such that the second end of the drive core supplies rotational torque to the fastener. 
     In some embodiments, rigidizing the ER fluid of the tool extension may comprise applying an electrical field to the ER fluid using one or more electrodes of the tool extension. Rigidizing the ER fluid of the tool extension may further comprise applying a compressive force to the ER fluid by decreasing an internal volume of the shell containing the ER fluid. Coupling the second end of the drive core to the fastener may comprise coupling the second end of the drive core to one of a plurality of differently sized tool elements and coupling the tool element to the fastener. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The concepts described in the present disclosure are illustrated by way of example and not by way of limitation in the accompanying figures. For simplicity and clarity of illustration, elements illustrated in the figures are not necessarily drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference labels have been repeated among the figures to indicate corresponding or analogous elements. The detailed description particularly refers to the accompanying figures in which: 
         FIG. 1A  is a side view of one illustrative embodiment of a tool extension removably coupled to a tool; 
         FIG. 1B  is a side view of the tool extension and the tool of  FIG. 1A , where the tool extension has been bent into a desired geometric configuration; 
         FIG. 2  is a perspective view of an input end of the tool extension of  FIG. 1A ; 
         FIG. 3  is a cross-sectional view of the tool extension of  FIG. 2 , taken along the section line  3 - 3  in  FIG. 2 ; 
         FIG. 4  is another cross-sectional view of the tool extension of  FIG. 2 , taken along the section line  4 - 4  in  FIG. 2 ; 
         FIG. 5  is a perspective view of an input end of another illustrative embodiment of a tool extension; 
         FIG. 6  is a cross-sectional view of the tool extension of  FIG. 5 , taken along the section line  6 - 6  in  FIG. 5 ; 
         FIG. 7  is another cross-sectional view of the tool extension of  FIG. 5 , taken along the section line  7 - 7  in  FIG. 5 ; and 
         FIG. 8  is a simplified flow diagram of one illustrative embodiment of a method of using one of the tool extensions of  FIGS. 2 and 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific exemplary embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure. 
     Referring now to  FIGS. 1A and 1B , one illustrative embodiment of a tool extension  10  removably coupled to a tool  16  is shown in simplified diagrams. As described in detail below, the tool extension  10  may be used to transfer rotational torque from an output  17  of the tool  16  to a hard-to-reach fastener  15  (e.g., a fastener disposed in a tight space, where the tool  16  may not be able fit). Although the tool  16  is illustratively shown in  FIGS. 1A and 1B  as a battery-powered cordless driver tool, it will be appreciated that the presently disclosed tool extensions  10  may be used with any type of tool having a rotating output, including, but not limited to, other types of power tools (e.g., an electrically- or pneumatically-powered impact wrench) and manually-operated tools (e.g., a manual ratchet wrench). 
     As shown in  FIGS. 1A and 1B , the tool extension  10  includes an input end  12  and an output end  14  opposite the input end  12 . In the illustrative embodiment, the input end  12  is configured to be removably coupled to the tool  16  (e.g., to an output shaft  17  of the tool  16 ) to receive rotational torque from the tool  16 . For instance, in some embodiments, such as those shown in  FIGS. 2 and 5  (and further discussed below), the input end  12  of the tool extension  10  may be formed to include a recess  26  that is shaped to receive a square drive  17  of the tool  16 . 
     The output end  14  of the tool extension  10  is configured to be removably coupled to a fastener  15  to supply rotational torque to the fastener  15 . In some embodiments, the output end  14  may be shaped to directly engage a certain type or types of fasteners. For instance, in one illustrative embodiment, the output end  14  of the tool extension  10  may be adapted to directly engage the head of a Phillips-type screw  15 . In other embodiments, to provide more versatility, the output end  14  may be configured to be indirectly coupled to a fastener  15  via one of a plurality of differently sized tool elements  13  in order to supply rotational torque to the fastener  15 . In other words, in such embodiments, the plurality of differently sized tool elements  13  may be used interchangeably with the tool extension  10  to allow use of the tool extension  10  with a plurality of different types of fasteners  15 . By way of example, as illustratively shown in  FIGS. 1A and 1B , the output end  14  of the tool extension  10  may include a square drive  11 . In such configurations, a user may removably couple a socket  13  (chosen from among a plurality of differently sized sockets  13 ) to the square drive  11  of the tool extension  10  and also engage the socket  13  with the fastener  15  to be tightened or loosened. It is also contemplated that, in still other embodiments, the output end  14  of the tool extension  10  may be formed to include a recess that is shaped to receive interchangeable tool elements  13  (e.g., differently sized screwdriver bits). 
     The tool extension  10  is shown in a straight (i.e., unbent) configuration in  FIG. 1A  and a bent configuration in  FIG. 1B . As described in more detail below, the tool extension  10  is able to transition, under the control of a user, back-and-forth between flexible and rigid states. When in a flexible state, a user of the tool extension  10  may bend the tool extension  10  into any number of desired shapes or geometric configurations between its input and output ends  12 ,  14 . For instance, when the tool extension  10  is in a flexible state, the user may bend the tool extension  10  from the configuration shown in  FIG. 1A  to that shown in  FIG. 1B . It is contemplated that, in some illustrative embodiments, bending the tool extension  10  may involve moving the output end  14  in three dimensions relative to the input end  12 . Once the user has bent the tool extension  10  into a desire shape or geometric configuration, the user may cause the tool extension  10  to transition to a rigid state to maintain that configuration (until the tool extension  10  is transitioned back to a flexible state). 
     Those skilled in the art will appreciate that terms like “flexible” and “rigid,” as well as related terms, have relative meanings in the present disclosure. As such, the “rigid” state of the tool extension  10  will be characterized by greater stiffness than the “flexible” state, but not necessarily complete stiffness. Likewise, the “flexible” state of the tool extension  10  will be characterized by less stiffness than the “flexible” state, but not necessarily a complete lack of stiffness. In other words, terms like “rigid” and “flexible” are used herein to denote relative increases and decreases, respectively, in stiffness and the ability to hold or maintain a shape. 
     Referring now to  FIGS. 2-4 , several detailed views of the input end  12  of the tool extension  10  are shown. The tool extension  10  includes a bendable drive core  18 . The drive core  18  may be illustratively embodied as a shaft or wire of any suitable material and/or configuration that is capable of transferring rotational torque from the input end  12  to the output end  14 , as well as bending along its length between the input end  12  to the output end  14 . For instance, in the illustrative embodiment of  FIGS. 2-4 , the drive core  18  is a solid shaft or wire (of varying radius near its ends, see  FIG. 4 ) formed of a metal or metal alloy. In other embodiments, the drive core  18  may be formed of a plurality of braided and/or wound components (e.g., flexible steel wrapped in wire, similar to a guitar string). In still other embodiments, the drive core  18  may be a tightly-wound spring. In yet other embodiments, the drive core  18  may be formed of a series of linked sections such that bending may occur at the joint between each pair of linked sections (even if the linked sections are not flexible along their individual lengths). 
     As shown in  FIGS. 2 and 4 , at the input end  12 , the drive core  18  may be formed with a recess  26  that is sized to receive the output shaft  17  of the tool  16 . For instance, in the illustrative embodiment, the recess  26  has a generally cubic shape adapted to receive a square drive  17 . As described above, at the output end  14 , the drive core  18  may include a feature that allows a plurality of differently sized tool elements  13  (e.g., sockets, screwdriver bits, or the like) to be interchangeably coupled to the drive core  18 . For instance, in the illustrative embodiment, the drive core  18  includes a square drive  11  positioned at the output end  14  of the tool extension  10 . 
     The tool extension  10  also includes a shell surrounding the drive core  18 . In the illustrative embodiment of  FIGS. 2-4 , this shell comprises an inner shell  20  and an outer shell  22 . The inner shell  20  surrounds the drive core  18  and is in contact with the drive core  18 . As such, in some embodiments, a lubricant may be provided between the drive core  18  and the inner shell  20  to reduce friction between these components when the drive core  18  rotates within the inner shell  20 . Additionally or alternatively, the inner shell  20  may be formed of a low-friction material. The outer shell  22  surrounds the inner shell  20 , such that a generally annular space is formed between the inner and outer shells  20 ,  22 . At the input end  12  of the tool extension  10 , the inner and outer shells  20 ,  22  are joined by an end plate  28 . Similarly, at the output end  14  of the tool extension  10 , the inner and outer shells  20 ,  22  are joined by another end plate (not shown). It is contemplated that, in other embodiments, the shell of the tool extension  10  may have other configurations than that just described. In the illustrative embodiment, both the inner and outer shells  20 ,  22  are formed of a flexible, insulating material, such as a plastic. 
     An electro-rheological (ER) fluid  24  is contained in the shell of the tool extension  10 . In the illustrative embodiment shown in  FIGS. 2-4 , the ER fluid  24  is disposed in the annular space formed between the inner and outer shells  20 ,  22 . ER fluids generally comprise small, polarized particles in viscous insulating liquids. As such, when an electric field is applied, an ER fluid may change its rheological characteristics, such as viscosity and/or dynamic yield strength. In the illustrative embodiment, when the ER fluid  24  is exposed to an electric field, the viscosity of the ER fluid  24  will increase dramatically. Additionally or alternatively, applying a compressive force to the ER fluid  24  may increase the viscosity of the ER fluid  24 . In these ways, the relative rigidity of the ER fluid  24  may be controlled to transition the ER fluid  24  between a flexible state in which the shell permits bending of the drive core  18  and a rigid state in which the shell resists bending of the drive core  18 . 
     While the ER fluid  24  is generally shown in  FIGS. 2-4  as occupying substantially all of the space between the inner and outer shells  20 ,  22 , in other embodiments the ER fluid  24  may be disposed in only portions of the space between the inner and outer shells  20 ,  22 . For instance, the ER fluid  24  might occupy one or more pockets formed between the inner and outer shells  20 ,  22  (while the remaining portions of the space between the inner and outer shells  20 ,  22  might be filled with air, or other components). 
     As best seen in  FIG. 4 , the end plate  28  of the tool extension  10  may comprise one or more electrodes  28  configured to selectively apply an electric field to the ER fluid  24  to cause the ER fluid  24  to transition from a flexible state to a rigid state. As shown in  FIG. 4 , the electrode(s)  28  may extend a distance into the space formed between the inner and outer shells  20 ,  22  and containing the ER fluid  24 . In some embodiments, the electrode(s)  28  (or wires connected thereto) may extend along the length of the tool extension  10  to ensure that the electrical field is applied relatively evenly to all portions of the ER fluid  24  when the electrode(s)  28  are supplied with an electric current. The tool extension  10  may include an on-board power source (not shown) positioned near and electrically coupled to the electrode(s)  28 . The power source may supply the electrode(s)  28  with electrical current (and, thus, increase the rigidity of the ER fluid  24 ) in response to a user input, such as a user of the tool extension  10  pressing a button coupled to the power source. In other embodiments, the electrode(s)  28  may be supplied with an electrical current by an external power source that is not a permanent part of the tool extension  10 . 
     So long as the electric field is applied to the ER fluid  24 , the increased rigidity of the ER fluid  24  will resist bending of the drive core  18  between the input and output ends  12 ,  14  of the tool extension  10  (but, generally, will not impede rotation of the drive core  18  inside the inner shell  20 ). In some embodiments, when the ER fluid  24  is in a rigid state, the shell of the tool extension  10  may apply a normal force to the drive core  18  that promotes the transfer of rotational torque from the input end  12  to the output end  14 . After the target fastener  15  has been tightened or loosened using the tool extension  10 , the user may release the button coupled to the power source (or, in other embodiments, press the same or a different button) to cause the power source to cease supplying electric current to the electrode(s)  28 , which will result in the ER fluid  24  returning to a flexible state. This will allow bending of the drive core  18  between the input and output ends  12 ,  14 , which may increase the ease of removing the tool extension  10  from the space in which it was being used. 
     Referring now to  FIGS. 5-7 , several detailed views of the input end  12  of another illustrative embodiment of a tool extension  10  are shown. This tool extension  10  may be removably coupled between a fastener  15  and a tool  16  in the same manner shown in  FIGS. 1A and 1B  and described in detail above. In the illustrative embodiment shown in  FIGS. 5-7 , the tool extension  10  has many of the same components as the tool extension  10  shown in  FIGS. 2-4 . As such, the same reference numerals have been used in  FIGS. 5-7  to indicate these components and the description set forth above (with reference is to  FIGS. 2-4 ) is equally applicable to the tool extension  10  of  FIGS. 5-7 , except as noted below. 
     Whereas the end plate  28  of the tool extension  10  of  FIGS. 2-4  comprised one or more electrodes, the end plate  28  of the illustrative embodiment of the tool extension  10  shown in  FIGS. 5-7  comprises one or more actuators  28 . As best seen in  FIG. 7 , the actuator(s)  28  are coupled to an annular ring  32  disposed within the annular space between the inner and outer shells  20 ,  22 . The actuator(s)  28  are operable (either electromechanically or manually) to move the annular ring  32  within the space between the inner and outer shells  20 ,  22 , parallel the length of the tool extension  10 . As such, when the actuator(s)  28  move the annular ring  32  toward the output end  14  of the tool extension  10 , the annular ring  32  decreases an internal volume of the shell of the tool extension  10 , thereby exerting a compressive force on the ER fluid  24  and increasing the viscosity of the ER fluid  24 . As such, the actuator(s)  32  may be used to selectively apply a compressive force to the ER fluid  24  to cause the ER fluid  24  to transition from a flexible state to a rigid state. 
     In some embodiments, the tool extension  10  may additionally or alternatively include one or more cylindrical sleeve actuators  34  positioned around sections of the outer shell  22  (one such sleeve actuator  34  being shown in phantom in  FIGS. 5 and 7 ). The sleeve actuator(s)  34  may be operable (e.g., electromechanically) to contract or squeeze a section of the outer shell  22  to decrease an internal volume of the shell of the tool extension  10 , thereby exerting a compressive force on the ER fluid  24  and increasing the viscosity of the ER fluid  24 . As such, the sleeve actuator(s)  34  may be used to selectively apply a compressive force to the ER fluid  24  to cause the ER fluid  24  to transition from a flexible state to a rigid state. It is contemplated that, in some embodiments, a tool extension  10  may include both electrode(s) for applying an electrical field to the ER fluid  24  and actuator(s) for applying a compressive force to the ER fluid  24  (which may be operable simultaneously or independently of one another). In such embodiments, the power source used to supply electrical current to the electrode(s) of the tool extension  10  may also be used to drive electromechanical actuators, such as solenoids, included in the tool extension  10 . 
     Referring now to  FIG. 8 , one illustrative embodiment of a method  80  of using a tool extension  10  (for instance, the tool extension  10  of  FIGS. 2-4  or the tool extension  10  of  FIGS. 5-7 ) is shown as a simplified flow diagram. The method  80  is illustrated in  FIG. 8  as a number of blocks  82 - 90 , each of which may be performed by user of the tool extension  10  and a tool  16 . 
     The method  80  begins with block  82 , in which a user removably couples the input end  12  of the drive core  18  of the tool extension  10  to the output  17  of the tool  16 . As described above, in some embodiments, the input end  12  of the tool extension  10  may be formed to include a recess  26  that is shaped to receive a square drive  17  of the tool  16 . As such, block  82  may involve inserting the square drive  17  of the tool  16  into the recess  26  formed in the drive core  18 . 
     In block  84 , a user removably couples the output end  14  of the drive core  18  of the tool extension  10  to the fastener  15 . As described above, in some embodiments, the output end  14  of the tool extension  10  may be configured to be indirectly coupled to a fastener  15  via one of a plurality of differently sized tool elements  13 . As such, in some embodiments of the method  80 , block  84  may involve removably coupling a selected tool element  13  to a square drive  11  of the drive core  18  and removably coupling the selected tool element  13  to the fastener  15 . 
     In block  86 , the user bends the tool extension  10  and, hence, the drive core  18  into a desired geometric configuration. This geometric configuration may be any shape that allows the tool extension  10  to extend between the fastener  15  and the tool  16 . A certain geometric configuration may be desirable, for instance, to accommodate a particular location of a fastener  15 . In some illustrative embodiments, block  86  may involve moving the output end  14  of the tool extension  10  in three dimensions relative to the input end  12  of the tool extension  10 . During block  86 , the ER fluid  24  of the tool extension  10  remains in a flexible state, such that the shell of the tool extension  10  permits bending of the drive core  18  between the input and output ends  12 ,  14  of the tool extension  10 . 
     It will be appreciated that the blocks  82 - 86  of the method  80  may be performed in any order, including performing two or more of blocks  82 - 86  simultaneously. For instance, in some embodiments of the method  80 , a user might first removably couple the input end  12  of the drive core  18  to the tool  16  (block  82 ), then bend the drive core  18  into the desired geometric configuration (block  86 ), and then removably couple the output end  14  of the drive core  18  to the fastener  15  (block  84 ). Furthermore, it is also contemplated that, in some embodiments, one or both of blocks  82 ,  84  may be performed after block  88 . 
     After block  86 , the method  80  proceeds to block  88 , in which the user rigidizes the ER fluid  24  contained in the shell surrounding the drive core  18 . In other words, in block  88 , the ER fluid  24  transitions from a flexible state to a rigid state. In some embodiments (such as those using the tool extension  10  shown in  FIGS. 2-4 ), block  88  may involve block  92 , as shown in phantom in  FIG. 8 . In block  92 , an electrical field is applied to the ER fluid  24  using one or more electrodes  28  to cause the ER fluid  24  to increase its rigidity. In some embodiments (such as those using the tool extension  10  shown in  FIGS. 5-7 ), block  88  may involve block  94 , as shown in phantom in  FIG. 8 . In block  94 , a compressive force is applied to the ER fluid  24  by decreasing an internal volume of the shell of the tool extension  10  (e.g., using one or more actuators  28 ,  34 ) to cause the ER fluid  24  to increase its rigidity. As mentioned above, it is also contemplated that some embodiments of block  88  may involve both applying an electrical field (block  92 ) and a compressive force (block  94 ) to the ER fluid  24 . In any case, rigidizing the ER fluid  24  in block  88  causes the shell of the tool extension  10  to resist bending of the drive core  18  and, thus, maintains the drive core  18  in the desired geometric configuration established in block  86 . 
     After blocks  82 - 88  have been performed, the method  80  proceeds to block  90 , in which the user operates the tool  16  to provide rotational torque to the fastener  15  via the drive core  18  of the tool extension  10 . In particular, operating the tool  16  will cause the output  17  of the tool  16  to rotate. As the input end  12  of the drive core  18  is coupled to the output  17  of the tool  16 , this rotation will be transferred to the drive core  18 , and the drive core  18  will rotate within the inner shell  20  of the tool extension  10 . When the output end  14  of the drive core  18  rotates, this rotation will be transferred to the fastener  15 . In some embodiments, rotation may be transferred from the drive core  18  to the fastener  15  indirectly via a tool element  13 . After the fastener  15  has been sufficiently tightened or loosened in block  90 , the user may cause the ER fluid  24  to transition from the rigid state back to a flexible state to allow for easier removal of the tool extension  10  from the space in which it was being used, as described above. 
     While certain illustrative embodiments have been described in detail in the figures and the foregoing description, such an illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected. There are a plurality of advantages of the present disclosure arising from the various features of the apparatus, systems, and methods described herein. It will be noted that alternative embodiments of the apparatus, systems, and methods of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of the apparatus, systems, and methods that incorporate one or more of the features of the present disclosure.