Abstract:
An improved extension pole ( 10 ) is provided having an outer tubular pole section ( 12 ) and an inner pole section ( 14 ) telescopically and reciprocally received within the section ( 12 ). The outer section ( 12 ) has a shock-absorbing component ( 38 ) mounted adjacent the base ( 20 ) thereof, which safely absorbs shocks incident to unrestrained fall of the inner pole section ( 14 ). The pole ( 10 ) also includes a fixture mounting element ( 74 ) with an associated locking member ( 88 ), the latter being threadably mounted and movable against the base of a fixture such as a light bulb changer ( 18 ), in order to securely mount the fixture in place on the pole ( 10 ). An improved, cam-type locking mechanism ( 16 ) is also provided which gives a short-throw twist operation through less than about a 45° arc.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is being filed contemporaneously with application for U.S. Design Pat. Ser. No. 29/206,848, entitled EXTENSION POLE, which is hereby incorporated by reference herein. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention is broadly concerned with multiple-section extension poles of the type commonly used for light bulb changing or other work in high or otherwise unaccessible locations. More particularly, the invention pertains to extension poles of this character including inner and outer, telescopically interfitted pole sections, wherein an improved, short-throw locking mechanism is provided allowing the user to quickly and easily lock the inner pole section relative to the outer pole section at any desired degree of extension. The invention also provides a unique shock-absorbing capacity which eliminates the possibility of pole damage in the event of unrestrained fall of the inner pole section. Finally, an improved fixture connection is provided in the form of a locking member adjacent the upper end of the extension pole permitting the user to firmly lock in place any desired operating fixture against inadvertent twist-off. 
   2. Description of the Prior Art 
   Extension poles have long been available for use by painters, other workmen or homeowners. Broadly speaking, such extension poles include one or more sections allowing the pole to assume varying lengths required for a given job. Moreover, a number of different operating tools have been used with these extension poles, for example light bulb changers or paint rollers. 
   Despite the widespread availability of conventional extension poles, a number of unresolved problems remain. For example, many such poles have a threaded shank or stub adjacent the outer end thereof for receiving a fixture. In the case of a light bulb changer for example the changer has a threaded shank which is secured to the stub. In use, however, during rotation of the extension pole while installing or uninstalling a light bulb, the fixture itself may begin to rotate and inadvertently twist entirely off of the connection stub. 
   Further, it often happens that through neglect or accident the inner pole section falls in an unrestrained fashion with considerable force against the bottom or base of the outer pole section. This can cause damage to the pole and even render it inoperative. 
   Finally, some prior poles have twist-type locking mechanisms serving to lock the inner pole section relative to the outer section at desired, relatively shifted locations. However, these prior mechanisms often require twisting of a collar or chuck through a significant degree of rotation in order to effect locking or unlocking. This can be an issue, particularly when the pole is extended and the operator must carefully manipulate the pole in order to avoid hitting nearby objects. 
   One prior pole assembly has a locking mechanism made up of three circumferentially spaced apart, axially extending locking fingers with a surrounding collar equipped with corresponding cam projections. In order to lock the pole, the operator grasps the collar and rotates it so as to inwardly deflect the fingers against the inner pole section. 
   There is accordingly a need in the art for improved extension poles which overcome the aforementioned problems and provide smooth, easy pole operation. 
   SUMMARY OF THE INVENTION 
   The present invention overcomes and provides an extension pole including a pair of telescopically interfitted inner and outer pole sections in the form of an outer section having a base and an inner pole section reciprocal within and relative to the outer section. In order to afford a high degree of shock-absorbing capacity, a resilient shock-absorbing component is located within the outer pole section proximal to the base thereof, in an orientation for engaging the inner pole section as it is lowered or dropped against the base. Preferably, the shock-absorbing component is in the form of a resilient synthetic resin pad which is directly engaged by the end of the inner pole section. 
   In order to provide a more secure connection of working fixtures to the outer end of an extension pole, the present invention provides an outwardly projecting tool supporting and securing element preferably in the form of a threaded shaft. Further, a threadably mounted locking member is disposed about the element, with the member operable for engaging the end of a supported fixture. Preferably, the locking member is in the nature of a jamb nut or collar which forcibly engages the inner end of the fixture, preventing inadvertent twist-off thereof. 
   Finally, the extension poles of the invention have improved locking mechanism characterized by short-throw operation, through less than 45° of arc. The preferred locking mechanism makes use of specially configured locking segments formed with camming regions; a rotatable chuck cam is mounted adjacent the locking segments so that upon rotation of the chuck the segments are displaced into tight frictional locking engagement with the inner pole section. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an elevational view of a preferred extension pole in accordance with the invention, illustrated with a bulb changer fixture on the tool, the changer being depicted in phantom; 
       FIG. 2  is an end view of the pole illustrated in  FIG. 1  viewed from the bottom end thereof remote from the fixture; 
       FIG. 3  is an end view of the pole of  FIG. 1 , viewing the end opposite that of  FIG. 2 , with the fixture omitted; 
       FIG. 4  is a fragmentary isometric view of the preferred pole, depicting the twist-lock operation thereof; 
       FIGS. 5   a  and  5   b  are respectively exploded views of the inner, slotted channel pole and the exterior, fluted stationary pole; 
       FIG. 6  is a sectional view taken along line  6 — 6  of  FIG. 1  and illustrating in detail the construction of the preferred collet cam locking mechanism; 
       FIG. 7   a  is a fragmentary view in partial vertical section and with parts broken away, illustrating in detail the construction of the fixture-supporting end of the pole; 
       FIG. 7   b  is a fragmentary view in vertical section illustrating the components of the preferred collet cam locking mechanism; 
       FIG. 7   c  is a fragmentary view in partial vertical section illustrating in detail the construction of the base end of the pole; 
       FIG. 8  is a fragmentary view in partial vertical section and partially in phantom, showing a fixture secured to the end of the pole, and with the locking sleeve of the pole in abutting, locking engagement with the fixture; 
       FIG. 9  is an isometric view of the preferred collet cam, shown in its open position prior to attachment to the inner channel pole; and 
       FIG. 10  is an end view of the collet cam depicted in  FIG. 9 , showing the opened condition of the cam in phantom and the closed position thereof in full lines. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Turning now to the drawings,  FIG. 1  illustrates an extension pole  10  in accordance with the invention. The pole  10  broadly includes an outer, extruded aluminum, fluted tubular pole section  12 , an inner pole section  14  telescopically received within the section  12 , and a locking mechanism  16  operably coupling the pole sections  12  and  14  and permitting locking of the section  14  at any one of a number of positions relative to section  12 . In  FIG. 1 , a light bulb changer  18  is shown in phantom, mounted on the end of section  14 . It will be understood however that the overall pole  10  is capable of supporting a number of different fixtures well known to those skilled in the art. 
   In more detail, the outer pole section  12  is in the form of an elongated tubular body  19  having a base  20  and upper open end  22 , the latter including a slot  23 . The base (see  FIG. 8 ) includes an end plug  24  having a central bore  26  and a reduced diameter upper end  28  adapted to fit within the confines of tubular body  19 . In addition, the end  28  is configured to present a groove  30  adapted to receive a resilient O-ring  32 . The overall base  20  further comprises a washer  34  which abuts plug  24  and compresses O-ring  32  in order to maintain the plug  24  within body  19 . To this end, a screw  36  is positioned within bore  26  and is threaded into a complemental bore forming a part of washer  32 . It will thus be seen that tightening of screw  36  serves to compress O-ring  32  between washer  34  and groove  30 . This effects a secure connection of the base  20  with body  19 . 
   Finally, the base  20  has a resilient, shock-absorbing foam pad  38  which engages the face of washer  34  remote from plug  24 . The pad  38  serves an important purpose to be described in detail below, namely to absorb impact loads incident to unrestrained retraction of inner pole section  14 . 
   Inner pole section  14  is in the form of an elongated, extruded aluminum body  40  adapted to fit within and telescope relative to the body  19 . The body  40  includes an elongated, axially extending groove  42  extending the full length thereof, with the groove having a pair of connection openings  44  adjacent the upper end thereof and a slot  46  adjacent the lower end thereof. 
   The lower end of body  40  has a guide plug  48  with a circular base  50  and an upstanding tubular segment  52  having a flat face  54  and slot  56 . The segment  52  is designed to fit within the inner end of body  40  as best seen in  FIG. 7   c . The guide plug  48  is retained in this position by means of an elongated, synthetic resin retainer  58  including a web  60  and boss  62 . The web  60  fits within groove  42  of body  40 , whereas boss  62  extends through the mating slots  46 ,  56 , thereby locking the guide plug in place. 
   The upper end of body  40  is equipped with a fixture mount  64  having a tubular connector stub  66  presenting a flat face  68  and a pair of threaded bores  70 . The mount  64  also has a radially enlarged wall  72  and outwardly extending mounting shaft  74  having coarse threading  76 . Also, the shaft  74  has fine threading  78  (see  FIG. 7   a ) between wall  72  and threading  76 . The mount  64  is secured to the upper end of body  40  by means of screws  80  which extend through the groove openings  44  and are threaded into bores  70 . 
   An annular locking member or sleeve  82  is also secured to the upper end of body  40 . The sleeve  82  includes an upper threaded section  84  presenting an abutment face  85 . The threaded section  84  mates with threading  78 . The sleeve  82  also includes an internal annular shoulder  86  and skirt  88 . The sleeve  82  is threaded onto the fine threading  78  of shaft  74 , and shoulder  86  bottoms out against wall  72 . It will be observed that the threading  84  permits sleeve  82  to be threaded outwardly along the length of shaft  74 . The importance of this feature will be made clear hereinafter. 
   The locking mechanism  16  includes a resilient synthetic resin tubular collet cam  90  and a chuck cam  92  designed to fit over the cam  90 . Specifically, the collet cam  90  has a tubular primary mounting section  94  made up of two hingedly connected half-sections  96  and  98 . As best seen in  FIGS. 7   b  and  9 , the half-section  96  has an inwardly extending boss  100 . The overall cam  90  also has a pair of elongated, axially extending, arcuate in cross-section locking segments  102 ,  104  which extend in an axial direction from the corresponding sections  96 ,  98 . The segments  102 ,  104  are specially configured and are supported by respective, elongated, axially extending connections portions  106 ,  108  integral with the associated sections  96 ,  98 . Each segment  102 ,  104  also has a slot or cut line  110 ,  112  so that the corresponding segment presents an axially extending, unrestrained outboard margin  102   a ,  104   a . Additionally, and as best seen in  FIG. 6 , each of the segments  102 ,  104  has, along the width thereof between the connection portions  106 ,  108  and the margins  102   a ,  104   a , a region of increased thickness  114 ,  116  which progresses from the connection portions toward the free margins. Thus, the regions  114 ,  116  present cam surfaces for each of the segments. It will be observed that the inner surfaces of each of the arcuate segments  102 ,  104  presents a radius of curvature. In order to maximize the camming action of the segments, the centers of the radii of curvature are offset. As shown in  FIG. 6 , the radius of curvature for the segment  102  has a center at C 102 , whereas the radius of curvature for the segment  104  has a center at C 104 . These centers C 102  and C 104  are slightly offset as depicted. 
   As illustrated in  FIGS. 9 and 10 , the collet cam  90  is manufactured from resilient synthetic resin material as a single component having the primary connection section  94  and segments  102 ,  104 . For ease of installation, during manufacture an elongated hinge region  118  is provided along the length of the half sections  96 ,  98 , thereby facilitating snap-on connection of the collet cam  90  onto tubular body  19 . In particular, this involves folding the opened cam  90  over the upper end of body  19  and insertion of boss  100  into slot  23 . 
   The chuck cam  92  is in the form of a tubular extruded aluminum body  120  having exterior fluting  122 , opposed inner and outer open ends  124 ,  126 , and a non-circular camming inner surface  127 . The chuck  92  is adapted to be fitted over collet cam  90  and to this end includes an internal annular shoulder  128  which abuts the transition between the half-sections  96 ,  98  and the segments  102 ,  104 . Additionally, the outer end  126  has an inturned lip  130  which covers the outer end of the segments  102 ,  104  (see  FIG. 7   b ). As shown in  FIG. 6 , the inner surface  127  of chuck cam  92  engageable with cam  90  has a pair of camming regions  131 ,  131   a . These regions interact with the regions  114 ,  116  of segment  102 ,  104  during rotation of chuck cam  92 . 
   During use of pole  10 , a fixture such as light bulb changer  18  is first mounted on shaft  74 . Referring to  FIG. 8 , it will be seen that the exemplary changer  18  has an internally threaded shank  132  as well as a resilient, conical light bulb holder  134 . The shank  132  is first threaded onto shaft  74 . Thereupon, the sleeve  82  is rotated until face  85  thereof comes into direct abutting engagement with the inner annular face of shank  132 . This serves to lock the fixture  18  in place on the shaft  74 , to prevent inadvertent loosening or detachment thereof during rotation of the pole  10 . 
   In the next step, the inner pole section  14  is extended relative to outer section  12 . This involves first loosening the locking mechanism  16  by rotation of chuck cam  92  in counter clockwise direction as viewed in  FIG. 4  and depicted by arrow  136 . The section  14  may then be extended to any desired extent, guided by boss  100  seated within groove  42  and ultimately limited by the abutment of base  50  of guide plug  48  against boss  100 , thus defining the maximum degree of extension of the section  14 . At any desired extension of the section  14 , the latter may be locked in place relative to outer section  12 . This involves merely a short twisting or rotational movement of chuck cam  92  in a direction opposite that shown in  FIG. 4  at arrow  136 . When this occurs, the regions  131 ,  131   a  of the inner surface  127  of the chuck cam  92  rides against and engages the cam regions  114 ,  116  of the locking segments  102 ,  104 . As a consequence, the locking segments come into firm, frictional locking engagement with the adjacent surfaces of body  19  of the inner pole section  12 , preventing any further movement of the inner section  14  relative to outer section  12 . A feature of the invention is that this locking/unlocking rotation of chuck  92  occurs through a relatively short arc, less than about 45°. 
   In the event that the chuck  92  is loosened either inadvertently or intentionally, the inner pole section  14  can freely fall under the influence of gravity toward base  20  of pole section  12 . In order to prevent any damage to the inner pole section or the base, the pad  38  comes into play. This pad is capable of safely absorbing any shock forces incident to unrestrained dropping of the inner pole section  14 , thereby enhancing the structural integrity of pole  10 . While in the preferred embodiment a resilient synthetic resin plug is used, it will be understood that other types of shock absorbing components, for example springs, could be used in lieu of the plug  38 . 
   The preferred forms of the invention described above are to be used as illustration only, and should not be utilized in a limiting sense in interpreting the scope of the present invention. Obvious modifications to the exemplary embodiments, as hereinabove set forth, could be readily made by those skilled in the art without departing from the spirit of the present invention. 
   The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set forth in the following claims.