Patent Publication Number: US-8973472-B2

Title: Tool extension bar

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a tool extension bar and, more particularly, to a tool extension bar suitable to have an application with a power tool and adapted to be connected to or disconnected from a tool member, such as a socket. 
     2. Description of the Related Art 
     U.S. Pat. No. 8,070,377 discloses a tool extension bar including a rod, a sleeve, a ball, and a spring. The rod has first and second sections. The first section of the rod includes an end for coupling with a pneumatic tool, and the second section of the rod extends from the other end of the first section. The sleeve is slideably mounted around the rod and includes an end for releasably coupling a bit. The sleeve includes an axial bore having larger and smaller sections. The larger section of the sleeve has polygonal cross sections corresponding to polygonal cross sections of the first section. A radial bore is formed in the sleeve and in communication with the smaller section. The ball is moveably received in the radial bore and moveably received in a recess of the second section of the rod to releasably engage the sleeve with the bit. The spring is mounted in the larger section of the axial bore of the sleeve and biases the sleeve from the retracted, second position to the extended, first position. The ball is engaged in the first contact section of the recess with an outermost portion of the ball projecting out of the radial bore of the sleeve when the sleeve is in the extended, first position, coupling the bit with the second end of the sleeve. The ball is engaged in the second contact section of the recess and does not project out of the radial bore of the sleeve when the sleeve is in the retracted, second position, allowing the bit to be disengaged from the second end of the sleeve. 
     However, the tool extension bar used with the pneumatic tool has some disadvantages. The pneumatic tool driven by a gas, usually compressed air supplied by a gas compressor, will certainly create vibration in operation. Thus, the spring is repeatedly retracted and extended to cause the sleeve to change from the first position to the second position. Therefore, the bit will disengage from the second end of the sleeve unintentionally. 
     Moreover, a user must grip on the end of the sleeve coupling to the bit and move the sleeve to cause the sleeve to move relative to the rod in the axial direction from the first position to the second position to allow the bit to be disengaged from the end of the sleeve. If the total length of the tool extension bar is very long, the user can not use it comfortably and can not grip the tool extension bar efficiently. In other words, it is not ergonomic. 
     The present invention is, therefore, intended to obviate or at least alleviate the problems encountered in the prior art. 
     SUMMARY OF THE INVENTION 
     The present invention solves this need and other problems in the field of extension bars by providing a tool extension bar including a rod, a sleeve assembly, an elastic member, and an engaging member. The rod includes first and second ends spaced in an axial direction. A recess is formed adjacent to the first end of the rod and includes a first contact section arranged adjacent to the first end of the rod and a second contact section extending toward the second end of the rod from an end of the first contact section. The second end of the rod is adapted to connect to and be driven by a power tool. The sleeve assembly is mounted around the rod and slideable relative to the rod in the axial direction between first and second positions. A radial hole extends in a radial direction perpendicular to the axial direction at an end of the sleeve assembly and aligns with the recess of the rod body. The elastic member is mounted around the second end of the rod and is biased against the rod and the sleeve assembly. The engaging member is movably received in the radial hole of the sleeve assembly in the radial direction and is moveably engaged in the recess of the rod in the axial and radial directions. The engaging member releasably engages the sleeve assembly with the rod. 
     When the sleeve assembly is moved to the first position, the engaging member is pushed by the radial hole of the sleeve assembly and engaged in the first contact section of the recess, with an outermost portion of the engaging member projecting out of the radial hole of the sleeve assembly and engaging with a tool member. 
     When the sleeve assembly is moved to the second position, the engaging member is engaged in the second contact section of the recess, with the outermost portion of the engaging member not projecting out of the radial hole of the sleeve assembly and disengaging from the tool member. 
     Preferably, the sleeve assembly includes a gripping member and a sleeve member mounted on an end of the gripping member. 
     The elastic member is a spring. 
     The engaging member is a ball. 
     An advantage of the tool extension bar according to the present invention is that one hand of the user can grip the first end of the gripping member and that another hand of the user can control the power tool. The user can control the sleeve assembly moved between the first and second positions at the first end of the gripping member spaced away the second end of the gripping member and the sleeve member connecting to the tool member. 
     Another advantage of the tool extension bar according to the present invention is that when the sleeve assembly is moved to the first position, the engaging member is engaged in the first contact section of the recess with the outermost portion of the engaging member projecting out of the radial hole of the sleeve member, engaging the tool member with the first end of the sleeve member. On the other hand, when the sleeve assembly is moved to the second position, the engaging member is engaged in the second contact section of the recess and does not project out of the radial hole of the sleeve member, allowing the tool member to be disengaged from the first end of the sleeve member. 
     A further advantage of the tool extension bar according to the present invention is that the two opposite ends of the elastic member are respectively compressed against the first contact surface of the convex portion of the rod and the second contact surface of the gripping member of the sleeve assembly. Thus, when the user does not grip the gripping member, the two opposite ends of the elastic member are respectively extended against the first contact surface of the convex portion of the rod and the second contact surface of the gripping member of the sleeve assembly to cause the sleeve assembly to move from the second position to the first position without strain. 
     The present invention will become clearer in light of the following detailed description of illustrative embodiments of this invention described in connection with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The illustrative embodiments may best be described by reference to the accompanying drawings where: 
         FIG. 1  shows a perspective view of a tool extension bar of a first embodiment according to the present invention. 
         FIG. 2  shows an exploded, perspective view of the tool extension bar of  FIG. 1 . 
         FIG. 3  shows a cross-section view taken along line  3 - 3  of  FIG. 1 . 
         FIG. 4  shows a partial, enlarged view of  FIG. 3 , and illustrates a sleeve assembly located at a first position. 
         FIG. 5  shows a continued, cross-section view of  FIG. 4 , and illustrates the sleeve assembly located at a second position. 
         FIG. 6  shows an exploded, perspective view of a tool extension bar of a second embodiment according to the present invention. 
         FIG. 7  shows a partial, enlarged cross-section view of  FIG. 6 . 
         FIG. 8  shows a perspective view of a tool extension bar according to the present invention, and illustrates the tool extension bar connected to a pneumatic tool. 
     
    
    
     All figures are drawn for ease of explanation of the basic teachings only; the extensions of the figures with respect to number, position, relationship, and dimensions of the parts to form the illustrative embodiments will be explained or will be within the skill of the art after the following teachings have been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength, and similar requirements will likewise be within the skill of the art after the following teachings have been read and understood. 
     Where used in the various figures of the drawings, the same numerals designate the same or similar parts. Furthermore, when the terms “first”, “second”, “third”, “fourth”, “end”, “portion”, “longitudinal”, “radial”, “diameter”, “width”, “thickness”, and similar terms are used herein, it should be understood that these terms have reference only to the structure shown in the drawings as it would appear to a person viewing the drawings and are utilized only to facilitate describing the illustrative embodiments. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIGS. 1 through 5  show a first embodiment of a tool extension bar according to the present invention shown in the drawings. The tool extension bar includes a rod  10 , a sleeve assembly  20  slidably mounted around the rod  10 , an elastic member  30  mounted on the rod  10 , and an engaging member  40 . 
     The rod  10  includes a first end  11 , a second end  12  spaced from the first end  11  along a first axis A, and a recess  13  formed adjacent to the first end  11 . The first and second ends  11  and  12  of the rod  10  respectively have a circular cross section. The recess  13  has a first contact section  131  arranged adjacent to the first end  11  of the rod  10 , and a second contact section  132  extending toward the second end  12  of the rod  10  from an end of the first contact section  131  opposite to the first end  11  of the rod  10 . A first height H 1  defined from the first contact section  131  to the first axis A in a radial direction perpendicular to the first axis A is greater than a second height H 2  defined from the second contact section  132  to the first axis A in the radial direction. Namely, the first contact section  131  having a depth in the radial direction perpendicular to the first axis A is less than that of the second contact section  132 . An engaging groove  14  is formed at an end face of the second end  12  of the rod  10  and adapted to connect to and be driven by a power tool, such as a pneumatic tool, an electric tool, or an automated machine. The rod  10  further includes a shoulder portion  15  disposed adjacent to the first end  11  thereof, a convex portion  16  disposed adjacent to the second end  12  thereof, and a body portion  17  formed between the shoulder and convex portions  15  and  16  along the first axis A. Two opposite ends of the shoulder portion  15  along the first axis A is defined with a first length L 1 . The shoulder portion  15  has a rectangular cross section perpendicular to the first axis A, and includes a width extended perpendicular to first axis A greater than an outer diameter of the first end  11  of the rod  10 . The convex portion  16  and the body portion  17  have circular cross sections perpendicular to the first axis A. The convex portion  16  includes an outer diameter less than an outer diameter of the second end  12  of the rod  10 . Moreover, the outer diameter of the convex portion  16  is greater than the width of the shoulder portion  15  and an outer diameter of the body portion  17 . The convex portion  16  includes a first contact surface  161  formed adjacent and connected to the body portion  17 . Two opposite ends of the body portion  17  along the first axis A is defined with a second length L 2  being at least three times as great as the first length L 1 . 
     The sleeve assembly  20  is mounted circumferentially outside the rod  10  and is slideable relative to rod  10  along the first axis A. The sleeve assembly  20  includes a gripping member  21  and a sleeve member  22  mounted on an end of the gripping member  21 . The gripping member  21  is generally cylindrical shaped and includes a first end  211  connected with the sleeve member  22  and a second end  212  spaced from the first end  211  of the gripping member  21  along the first axis A. An outer diameter of the first end  211  of the gripping member  21  is less than that of the second end  212  of the gripping member  21 . The gripping member  21  further includes a through hole  213  extending from the first end  211  of the gripping member  21  to the second end  212  of the gripping member  21  to receive the body portion  17  of the rod  10 , so that the gripping member  21  completely covers the body portion  17  of the rod  10 . The through hole  213  includes an expanded section  214  formed adjacent to the second end  212  of the gripping member  21  along the first axis A. A second contact surface  215  is formed between an inner periphery of the through hole  213  and an inner periphery of the expanded section  214 . Thus, the elastic member  30  is received in the expanded section  214  of the gripping member  21 . The sleeve member  22  includes a first end  221  adapted for connecting to a tool member, such as a socket, a second end  222  spaced from the first end  221  along the first axis A and connected to the first end  211  of the gripping member  21 , and a coupling hole  223  extending between the first and second ends  221  and  222  thereof to mount around the first end  11  of the rod  10 . The coupling hole  223  of the sleeve member  22  is connected and in communication with the through hole  213  of the gripping member  21 . The coupling hole  223  includes a larger section  224 , a smaller section  225 , and a middle section  226  arranged between the larger and smaller sections  224  and  225  along the first axis A. The larger section  224  has a circular cross section perpendicular to the first axis A and corresponding to the circular cross section of the body portion  17  of the rod  10 . The smaller section  225  has a circular cross section perpendicular to the first axis A and corresponding to the circular cross section of the first end  11  of the rod  10 . The middle section  226  has a rectangular cross section perpendicular to the first axis A and corresponding to the rectangular cross section of the shoulder portion  15  of the rod  10  to increase the joint strength between the rod  10  and the sleeve assembly  20  to cause the rod  10  to be adapted to connect to and be driven by a high torque power tool. Moreover, the sleeve member  22  further includes a radial hole  227  extending along a second axis B perpendicular to the first axis A from an outer periphery of the first end  221  of the sleeve member  22  through an inner periphery of the smaller section  225  of the coupling hole  223 . The radial hole  227  aligns with the recess  13  of the rod  10 . In a preferred form, the first end  221  of the sleeve member  22  has a rectangular cross section perpendicular to the first axis A, and the second end  222  of the sleeve member  22  has a circular cross section perpendicular to the first axis A. 
     The elastic member  30  is mounted around the body portion  17  of the rod  10  and is received in the expanded section  214  of the gripping member  21 . In a preferred form, the elastic element  30  is a spring. Two opposite ends of the elastic member  30  respectively abut and are biased against the first contact surface  161  of the convex portion  16  of the rod  10  and the second contact surface  215  of the gripping member  21  of the sleeve assembly  20 . 
     The engaging member  40  is movably received in the radial hole  227  of the sleeve member  22  of the sleeve assembly  20  along the second axis B. Moreover, the engaging member  40  is also moveably engaged in the first and second contact sections  131  and  132  of the recess  13  of the rod  10  along the first and second axes A and B to releasably engage the sleeve assembly  20  with the rod  10 . In a preferred form, the engaging member  40  is a ball. A distal end of the radial hole  227  of the sleeve member  22  adjacent to the outer periphery of the first end  221  of the sleeve member  22  having an inner diameter is less than an outer diameter of the engaging member  40  to avoid the engaging member  40  disengaging from the radial hole  227  of the sleeve member  22 , such that a outermost portion  41  of the engaging member  40  selectively projects out of the radial hole  227  of the sleeve member  22  to engage the sleeve assembly  20  with the tool member. 
     The sleeve assembly  20  is moveable relative to rod  10  along the first axis A between a first position (shown in  FIG. 4 ) and a second position (shown in  FIG. 5 ). The elastic element  30  is compressed when the sleeve assembly  20  is in the second position. When the sleeve assembly  20  is moved to the first position, the engaging member  40  is pushed by the radial hole  227  of the sleeve member  22  and is engaged in the first contact section  131  of the recess  13 . As mentioned above, the first contact section  131  has the depth in the radial direction perpendicular to the first axis A less than that of the second contact section  132 . Thus, when the engaging member  40  is seated in the first contact section  131 , the outermost portion  41  of the engaging member  40  projects out of the radial hole  227  of the sleeve member  22  and engages with the tool member. Therefore, the tool member is securely locked on the tool extension bar and can be driven when the rod  10  of the tool extension bar secured to the power tool rotates. 
     Referring to  FIG. 5 , when a user grips the gripping member  21  and moves it along the first axis A to cause the sleeve assembly  20  to move to the second position, the engaging member  40  is pushed by the radial hole  227  of the sleeve assembly  20  and is moved along the second axis B to engage in the second contact section  132  of the recess  13 . As mentioned above, the outermost portion  41  of the engaging member  40  does not project out of the radial hole  227  of the sleeve assembly  20  and disengages from the tool member. Therefore, the tool member is quickly unlocked on the tool extension bar. The two opposite ends of the elastic member  30  are respectively compressed against the first contact surface  161  of the convex portion  16  of the rod  10  and the second contact surface  215  of the gripping member  21  of the sleeve assembly  20 . Thus, when the user does not grip the gripping member  21 , the two opposite ends of the elastic member  30  respectively extend against the first contact surface  161  of the convex portion  16  of the rod  10  and the second contact surface  215  of the gripping member  21  of the sleeve assembly  20  to cause the sleeve assembly  20  to move from the second position to the first position without strain. 
       FIGS. 6 and 7  show a second embodiment of the tool extension bar according to the present invention shown in the drawings. Specifically, an annular engaging portion  216  is formed at the first end  211  of the gripping member  21 , and extends along the first axis A toward the second end  222  of the sleeve member  22 . An annular engaging recess  228  is formed at the second end  222  of the sleeve member  22  and is engaged with the engaging portion  216  of the gripping member  21  to cause the gripping member  21  and the sleeve member  22  to rotatable connect with each other. 
       FIG. 8  shows the second end  12  of the rod  10  connected to a pneumatic tool  2 . Therefore, one hand of the user can grip the first end  211  of the gripping member  21 , and another hand of the user can control the pneumatic tool  2 . Thus, the user can move the gripping member  21  to cause the sleeve assembly  20  to move between the first and second positions. Namely, the user can control the sleeve assembly  20  to move between the first and second positions at the first end  211  of the gripping member  21  spaced away the second end  212  of the gripping member  21  and the sleeve member  22  connecting to the tool member. 
     The tool extension bar includes the following advantages: 
     1. One hand of the user can grip the first end  211  of the gripping member  21  and another hand of the user can control the pneumatic tool  2 . The user can control the sleeve assembly  20  to move between the first and second positions at the first end  211  of the gripping member  21  spaced away the second end  212  of the gripping member  21  and the sleeve member  22  connecting to the tool member. 
     2. When the sleeve assembly  20  is moved to the first position, the engaging member  40  is engaged in the first contact section  131  of the recess  13  with the outermost portion  41  of the engaging member  40  projecting out of the radial hole  227  of the sleeve member  22 , engaging the tool member with the first end  221  of the sleeve member  22 . On the other hand, when the sleeve assembly  20  is moved to the second position, the engaging member  40  is engaged in the second contact section  132  of the recess  13  and does not project out of the radial hole  227  of the sleeve member  22 , allowing the tool member to be disengaged from the first end  221  of the sleeve member  22 . 
     3. The two opposite ends of the elastic member  30  are respectively compressed against the first contact surface  161  of the convex portion  16  of the rod  10  and the second contact surface  215  of the gripping member  21  of the sleeve assembly  20 . Thus, when the user does not grip the gripping member  21 , the two opposite ends of the elastic member  30  respectively extend against the first contact surface  161  of the convex portion  16  of the rod  10  and the second contact surface  215  of the gripping member  21  of the sleeve assembly  20  to cause the sleeve assembly  20  to move from the second position to the first position without strain. 
     Thus since the illustrative embodiments disclosed herein may be embodied in other specific forms without departing from the spirit or general characteristics thereof, some of which forms have been indicated, the embodiments described herein are to be considered in all respects illustrative and not restrictive. The scope is to be indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.