Patent Document

[0001]    This is a continuation-in-part of application Ser. No. 08/106,063 filed Aug. 13, 1993, now pending. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates generally to chucks for use with drills or with electric or pneumatic power drivers. More particularly, the present invention relates to a chuck of the keyless type which may be tightened or loosened by hand or by actuation of the driver motor.  
           [0003]    Both hand and electric or pneumatic tool drivers are well known. Although twist drills are the most common tools used with such drivers, the tools may also comprise screwdrivers, nut drivers, burrs, mounted grinding stones and other cutting or abrading tools. Since the tools may have shanks of varying diameter or the cross-section of the tool shank may be polygonal, the device is usually provided with a chuck which is adjustable over a relatively wide range. The chuck may be attached to the driver by a threaded or tapered bore.  
           [0004]    A wide variety of chucks have been developed in the art. In the simplest form of chuck, three jaws spaced circumferentially approximately 120 degrees apart from each other are constrained by angularly disposed passageways in a body attached onto the drive shaft and configured so that rotation of the body in one direction relative to a constrained nut engaging the jaws forces the jaws into gripping relationship with respect to the cylindrical shank of a tool, while rotation in the opposite direction releases the gripping relationship. Such a chuck may be keyless if it is rotated by hand. One example of such a chuck is disclosed in U.S. Pat. No. 5,125,673 entitled “Non-Impact Keyless Chuck” commonly assigned to the present assignee, and whose entire disclosure is incorporated by reference herein.  
           [0005]    Despite the success of keyless chucks such as set forth in U.S. Pat. No. 5,125,673, varying configurations of chucks are desirable for a variety of applications. Currently utilized in a variety of chuck applications are ball bearings for reducing friction between the nut and body from axial thrust of the nut onto the body. These bearings are sometimes caged and have separate top and bottom thrust races. Sometimes the body or the nut, if hard enough, can serve as the bottom or top thrust race, respectively. It would be desirable to have a keyless chuck that requires fewer components or lower manufacturing or assembly cost. In addition, it would be desirable to have a chuck configuration whereby radial as well as axial thread stresses were minimized when the chuck was operated. Further, it would be desirable to have a chuck whereby the front sleeve is maintained in place by a nosepiece that is both functional and serves an aesthetic purpose.  
         SUMMARY OF THE INVENTION  
         [0006]    The present invention recognizes and addresses the foregoing considerations, and others of prior art constructions and methods.  
           [0007]    Accordingly, it is an object of the present invention to provide an improved chuck.  
           [0008]    It is another object of the present invention to provide a chuck that minimizes radial as well as axial stress during operation.  
           [0009]    It is another object of the present invention to provide a keyless chuck that has a minimum number of individual components that must be assembled.  
           [0010]    It is another object of the present invention to provide a chuck with an improved nosepiece that is both decorative and retains the front sleeve in place.  
           [0011]    Yet another object of the present invention is to provide an improved mechanism for maintaining a one-piece nut on the body of a chuck.  
           [0012]    These and other objects are achieved by providing a chuck for use with a manual or power driver having a rotatable drive shaft, the chuck comprising a generally cylindrical body member having a nose section and a tail section. The tail section has an axial bore formed therein to mate with the drive shaft of the driver, and the nose section has an axial bore formed therein and a plurality of angularly disposed passageways formed therethrough and intersecting the axial bore. The chuck further includes a plurality of jaws slidably positioned in each of the angularly disposed passageways, each of the jaws having a jaw face formed on one side thereof and threads formed on the opposite side thereof. The chuck further includes a nut rotatably mounted on the body and in engagement with the threads of the jaws and a bearing thrust ring fixed on the body member. The chuck further includes a self-contained anti-friction bearing assembly disposed between the nut and the thrust ring and a generally cylindrical front sleeve member in driving engagement with the nut and overlying the nose section of the body member whereby when the front sleeve member is rotated with respect to the body member, the jaws will be moved thereby.  
           [0013]    These and other objects are also accomplished by providing a chuck for use with a manual or power driver having a rotatable drive shaft, the chuck comprising a generally cylindrical body member having a nose section and a tail section, the tail section having an axial bore formed therein to mate with the drive shaft of the driver, and the nose section having an axial bore formed therein and a plurality of angularly disposed passageways formed therethrough and intersecting the axial bore. The chuck further includes a plurality of jaws slidably positioned in each of the angularly disposed passageways, each of the jaws having a jaw face formed on one side thereof and threads formed on the opposite side thereof. The chuck further includes a nut rotatably mounted on the body and in engagement with the threads on the jaws, and a generally cylindrical front sleeve member overlying the nose section of the body member and in driving engagement with the nut. The chuck further includes a rust-resistant nosepiece adapted to be secured to the nose section of the body, the nosepiece maintaining the front sleeve member in driving engagement with the nut, whereby when said front sleeve member is rotated with respect to the body member, the jaws will be moved thereby.  
           [0014]    These and other objects are further accomplished by providing a chuck for use with a manual or powered driver having a rotatable drive shaft, the chuck comprising a generally cylindrical body member having a nose section and a tail section. The tail section is adapted to mate with the drive shaft of the driver and the nose section having an axial bore formed therein and a plurality of angularly disposed passageways formed therethrough and intersecting said axial bore. The chuck further includes a plurality of jaws slidably positioned in the angularly disposed passageways, each of the jaws having a jaw face formed on one side thereof. The chuck further including a nut rotatably mounted on the body member and in engagement with the threads on the jaws. The chuck further includes a nut retainer member received on the body for maintaining the nut on the body, the nut retainer member including a frusto-conical portion. The chuck further includes a generally cylindrical front sleeve member in driving engagement with the nut and overlying the nose section of the body member whereby when the front sleeve member is rotated with respect to the body member, the jaws will be moved thereby. In a preferred embodiment, the nut retainer member further includes a cylindrical portion which is press fitted onto the body member.  
           [0015]    Other objects, features and aspects of the present invention are discussed in greater detail below. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    A full and enabling disclosure of the present invention, including the best mode thereof, to one of ordinary skill in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:  
         [0017]    [0017]FIG. 1 is a longitudinal view, partly in section, of a chuck in accordance with an embodiment of the present invention;  
         [0018]    [0018]FIG. 2 is an exploded view of the chuck illustrated in FIG. 1;  
         [0019]    [0019]FIG. 3 is a longitudinal view, partly in cross-section of another embodiment in accordance with the present invention; and  
         [0020]    [0020]FIG. 4 is an exploded view of the chuck illustrated in FIG. 3. 
     
    
       [0021]    Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention.  
       DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0022]    It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention, which broader aspects are embodied in the exemplary construction.  
         [0023]    Referring to FIGS. 1 and 2, a chuck  10  in accordance with the present invention is illustrated. Chuck  10  includes a front sleeve member  12 , an optional rear sleeve member  14 , a body member  16  and jaws  18 . Body member  16  is generally cylindrical in shape and comprises a nose or forward section  20  and a tail or rearward section  22 . An axial bore  24  is formed in the nose section  20  of the body member  16 . Axial bore  24  is somewhat larger than the largest tool shank that the chuck is designed to accommodate. A threaded bore  26  is formed in tail section  22  of body  16  and is of a standard size to mate with the drive shaft of a powered or hand driver (not shown). The bores  24 ,  26  may communicate at the central region  28  of body member  16 . While a threaded bore  26  is illustrated, such bore could be replaced with a tapered bore of a standard size to mate with a tapered drive shaft.  
         [0024]    Passageways  30  are formed in body member  16  to accommodate each jaw  18 . Preferably, three jaws  18  are employed and each jaw  18  is separated from the adjacent jaw by an arc of approximately 120 degrees. The axes of the passageways  30  and the jaws  18  are angled with respect to the chuck axis but intersect the chuck axis at a common point ahead of the chuck body  16 . Each jaw  18  has a tool engaging face  32  which is generally parallel to the axis of the chuck body  16  and threads  34  on its opposite or outer surface. Threads  34  of any suitable type and pitch may be utilized within the scope of the present invention as would be readily apparent to one skilled in the art.  
         [0025]    As illustrated in FIGS. 1 and 2, body member  16  includes a thrust ring member  36  which, in a preferred embodiment, is integral therewith. Thrust ring member  36  includes a thrust face  38 . Thrust face  38  includes an arcuate seating surface  40  for engagement with the inner race of a self-contained anti-friction bearing assembly  42  as will be described in more detail below. Thrust ring member  36  includes a plurality of jaw guideways  30  formed around the circumference to permit retraction of the jaws  18  therethrough.  
         [0026]    Body member  16  includes a rear cylindrical portion  44  with a knurled surface  46  thereon for receipt of optional rear sleeve  14  to be pressed thereon if so desired. Body  16  further includes a first tapered portion  48  extending from rear cylindrical portion  44  to thrust ring  36 . A second tapered portion  50  extends from the area of thrust face  38  to a front cylindrical portion  52 . Front cylindrical portion  52  is of greater diameter than the smaller end of second tapered portion  50  and forms a first circumferential groove  54  intermediate the nose and tail sections  20  and  22  of body  16 . Body  16  further includes a reduced diameter nose portion  56  that is adapted to receive a nosepiece  58  as will be described in more detail below.  
         [0027]    The present invention further includes a nut  60  which, in a preferred embodiment, is a split nut and which includes threads  62  for mating with threads  34  on jaws  18  whereby when said nut is rotated with respect to said body, said jaws will be advanced or retracted. Nut  60  is adapted to receive a retaining band  64  for maintaining nut  60  together after it is assembled. In the illustrated embodiment, a split nut is utilized because of the diameter of front cylindrical portion  52 . Nut  60  includes drive slots  66  for mating with drive ribs  68  on front sleeve  12  so that when front sleeve  12  is rotated, nut  60  will rotate therewith and move jaws  18  as set forth above.  
         [0028]    A self-contained bearing assembly  42  is adapted to be placed between thrust ring  36  and a face  70  of nut  60 . Self-contained bearing assembly  42  includes an inner race  72 , an outer race  74  and bearing elements  76  maintained therebetween. In a preferred embodiment, bearing elements  76  are ball bearings. Self-contained bearing assembly  42  may further include a shroud  78  surrounding the inner and outer races  72 ,  74  for maintaining the bearing assembly as a self-contained component. Inner race  72  includes an arcuate surface that is dimensioned and configured to mate with arcuate seating surface  40  on thrust face  38  of thrust ring  36 . Such mating relationship assists in alignment and minimization of both axial and radial stresses when the chuck is operated. In a preferred embodiment, self-contained bearing assembly  42  is a radial thrust bearing.  
         [0029]    Use of a self-contained bearing assembly has a number of advantages. Assembly is greatly simplified in that individual ball bearings and cages do not have to be handled. In addition, the body and nut are not required to be as hard or dense as is necessary with conventional bearing systems where the body or nut may also serve as a thrust race, thus allowing more flexibility in materials and reducing secondary manufacturing operations and, ultimately, cost.  
         [0030]    Front sleeve member  12  is adapted to be loosely fitted over nose section  20  of chuck  10 . Drive ribs  68  of front sleeve  12  engage drive slots  66  of nut  60  so that front sleeve  12  and nut  60  will be operatively connected, i.e., when front sleeve  12  is rotated, nut  60  will rotate therewith. Front sleeve  12  includes an annular ledge portion  79  adapted to rest at the inner face of front cylindrical portion  52  and nose portion  56 . Nosepiece  58  is dimensioned and adapted to be pressed onto nose portion  56  to maintain front sleeve  12  on chuck  10 . It should be appreciated that nosepiece  58  could also be secured by snap fit, threading or the like. Nosepiece  58  is exposed when said chuck is assembled and is preferably coated with a non-ferrous metallic coating to prevent rust and to enhance its appearance. In a preferred embodiment, such coating may be zinc or nickel, however, it should be appreciated that any suitable coating could be utilized.  
         [0031]    Nosepiece  58  serves to maintain front sleeve member  12  in position on chuck  10  and in driving engagement with nut  60 . In addition, nosepiece  58  serves the dual purpose of providing an aesthetically pleasing cover for nose portion  56  that inhibits rust. This provides the advantage of an aesthetically pleasing appearance without the necessity to coat the entire body member  16  with a non-ferrous material. If desired, the rear sleeve member  14  may be omitted and the front sleeve member  12  extended to the tail end of body  16 . This alternative is feasible when a spindle lock or the like is provided on the driver or when the driver is used to tighten or loosen the jaws.  
         [0032]    The circumferential surface of the front sleeve member  12  may be knurled or may be provided with longitudinal ribs or other protrusions to enable the operator to grip it securely. In like manner, the circumferential surface of the rear sleeve member  14 , if employed, may be knurled or ribbed if desired. The front and rear sleeves may be fabricated from a structural plastic such as polycarbonate, a filled polypropylene, for example, glass filled polypropylene, or a blend of structural plastic materials. Other composite materials such as, for example, graphite filled polymerics would also be suitable in certain environments. As will be appreciated by one skilled in the art, the materials from which the chuck of the present invention is fabricated will depend on the end use of the chuck, and the above are provided by way of example only.  
         [0033]    It will be appreciated that rear sleeve member  14  is fixed to body member  16  while front sleeve member  12  is operatively associated with nut  60  and secured to body member  16  for relative rotation therewith. Relative movement of the front and rear sleeve members,  12  and  14 , due to the interaction between threads  34  on jaws  18  and threads  62  on nut  60  causes jaws  18  to be advanced or retracted, depending upon the direction of relative movement.  
         [0034]    Referring to FIGS. 3 and 4, a chuck  110  in accordance with another embodiment of the present invention is illustrated. Chuck  110  includes a front sleeve member  112 , an optional rear sleeve member  114 , a body member  116  and jaws  118 . Body member  116  is generally cylindrical in shape and comprises a nose or forward section  120  and a tail or rearward section  122 . An axial bore  124  is formed in the nose section  120  of the body member  116 . Axial bore  124  is somewhat larger than the largest tool shank that the chuck is designed to accommodate. A threaded bore  126  is formed in tail section  122  of body  116  and is of a standard size to mate with the drive shaft of a powered or hand driver (not shown). The bores  124 ,  126  may communicate at the central region  128  of body member  116 . While a threaded bore  126  is illustrated, such bore could be replaced with a tapered bore of a standard size to mate with a tapered drive shaft.  
         [0035]    Passageways  130  are formed in body member  116  to accommodate each jaw  118 . Preferably, three jaws  118  are employed and each jaw  118  is separated from the adjacent jaw by an arc of approximately 120 degrees. The axes of the passageways  130  and the jaws  118  are angled with respect to the chuck axis but intersect the chuck axis at a common point ahead of the chuck body  116 . Each jaw  118  has a tool engaging face  132  which is generally parallel to the axis of the chuck body  116  and threads  134  on its opposite or outer surface. Threads  134  of any suitable type and pitch may be utilized within the scope of the present invention as would be readily apparent to one skilled in the art.  
         [0036]    As illustrated in FIGS. 3 and 4, body member  116  includes a thrust ring member  136  which, in a preferred embodiment, is integral therewith. Thrust ring member  136  includes a plurality of jaw guideways  150  formed around the circumference to permit retraction of the jaws  118  therethrough. Thrust ring member  136  may have an arcuate seating surface for receipt of a self-contained bearing assembly as described in the above embodiment.  
         [0037]    Body member  116  includes a rear cylindrical portion  144  with a knurled surface  146  thereon for receipt of optional rear sleeve  114  to be pressed thereon if so desired.  
         [0038]    The present invention further includes a nut  160  which, in a preferred embodiment, is a unitary nut and which includes threads  162  for mating with threads  134  on jaws  118  whereby when said nut is rotated with respect to said body, said jaws will be advanced or retracted. As illustrated in FIG. 4, nut  160  includes drive slots  166  for mating with drive ribs  168  on front sleeve  112  so that when front sleeve  112  is rotated, nut  160  will rotate therewith and move jaws  118  as set forth above.  
         [0039]    A self-contained bearing assembly  142  is adapted to be placed between thrust ring  136  and a face  170  of nut  160 . Self-contained bearing assembly  142  includes an inner race  172 , an outer race  174  and bearing elements  176  maintained therebetween. In a preferred embodiment, bearing elements  176  are ball bearings. Self-contained bearing assembly  142  may further include a shroud  178  surrounding the inner and outer races  172 ,  174  for maintaining the bearing assembly as a self-contained component. Inner race  172  may include an arcuate surface that is dimensioned and configured to mate with an arcuate seating surface on the thrust face of thrust ring  136  such as illustrated in the previous embodiment, if so desired. Such mating relationship assists in alignment and minimization of both axial and radial friction when the chuck is operated. In a preferred embodiment, self-contained bearing assembly  142  is a radial thrust bearing. It should be appreciated that any type bearing arrangement including plain bearing surfaces could be utilized in the present invention.  
         [0040]    Referring again to FIGS. 3 and 4, a nut retainer member is generally illustrated at  143 . Nut retainer member  143  includes a first generally cylindrical portion  145  and a second frusto-conical portion  147 . Substantially cylindrical portion  145  is configured to be press fitted over nose or forward section  120  in a location so that a portion  149  will engage nut  160  to prevent nut  160  from moving axially forward more than a desired amount. This desired amount can be determined by the location in which the nut retainer member is pressed onto the body member. It should be appreciated that the nut retainer member  143  is adapted to be press fitted onto the nose portion of the body, but could be secured in any other suitable manner in accordance with the present invention. Nut member  160  defines a ledge  151  and nut retainer member  143 , through its portion  149 , is adapted to be received on ledge  151  when contact is made between nut  160  and nut retainer member  143 .  
         [0041]    Front sleeve member  112  is adapted to be loosely fitted over nose section  120  of chuck  110 . Drive ribs  168  of front sleeve  112  engage drive slots  166  of nut  160  so that front sleeve  112  and nut  160  will be operatively rotationally connected, i.e., when front sleeve  112  is rotated, nut  160  will rotate therewith.  
         [0042]    A nosepiece  158  is dimensioned and adapted to be pressed onto the front of the forward section  120  of body member  116  to maintain front sleeve  112  on chuck  110 . It should be appreciated that nosepiece  158  could also be secured by snap fit, threading or the like. Nosepiece  158  is exposed when the chuck is assembled and is preferably coated with a non-ferrous metallic coating to prevent rust and to enhance its appearance. In a preferred embodiment, such coating may be zinc or nickel, however, it should be appreciated that any suitable coating could be utilized.  
         [0043]    Nosepiece  158  serves to maintain front sleeve member  112  in position on chuck  110  and in driving engagement with nut  160 . In addition, nosepiece  158  serves the dual purpose of providing an aesthetically pleasing cover for nose portion  156  that inhibits rust. This provides the advantage of an aesthetically pleasing appearance without the necessity to coat the entire body member  116  with a non-ferrous material. If desired, the rear sleeve member  114  may be omitted and the front sleeve member  112  extended to the tail end of body  116 . This alternative is feasible when a spindle lock or the like is provided on the driver or when the driver is used to tighten or loosen the jaws.  
         [0044]    It should also be appreciated that a snap ring or any other mechanism could be utilized to maintain front sleeve  112  in place in lieu of nosepiece  158 .  
         [0045]    The circumferential surface of the front sleeve member  112  may be knurled or may be provided with longitudinal ribs or other protrusions to enable the operator to grip it securely. In like manner, the circumferential surface of the rear sleeve member  114 , if employed, may be knurled or ribbed if desired. The front and rear sleeves may be fabricated from a structural plastic such as polycarbonate, a filled polypropylene, for example, glass filled polypropylene, or a blend of structural plastic materials. Other composite materials such as, for example, graphite filled polymerics would also be suitable in certain environments. As will be appreciated by one skilled in the art, the materials from which the chuck of the present invention is fabricated will depend on the end use of the chuck, and the above are provided by way of example only.  
         [0046]    It will be appreciated that rear sleeve member  114  is fixed to body member  116  while front sleeve member  112  is operatively associated with nut  160  and secured to body member  116  for relative rotation therewith. Relative movement of the front and rear sleeve members,  112  and  114 , due to the interaction between threads  134  on jaws  118  and threads  162  on nut  160  causes jaws  118  to be advanced or retracted, depending upon the direction of relative movement.  
         [0047]    While the above description is set forth with respect to a keyless chuck, it should be appreciated that the principles of the present invention may be equally applicable to a keyed chuck, and such is within the scope of the present invention.  
         [0048]    These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present invention, which is more particularly set forth in the appended claims. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to be limitative of the invention so further described in such appended claims.

Technology Category: 4