Abstract:
A multi-section telescoping pole for manipulating a tool. Sections of the pole have apertures. A pinch safety locking assembly includes a button configured for movement by a digit on a user&#39;s hand to a first position by a first resilient member when received in aligned first and second apertures to restrain the second section from moving relative to the first section and to a second position against a resistance provided by the first resilient member and against an elastic stop to permit relative longitudinal movement between the first and second sections. The pinch safety locking assembly is additionally configured to facilitate assembly by movement of the button by use of an excessive force to a third position against a combined resistance of the first resilient member and the elastic stop to permit relative movement between the pinch safety locking assembly and the second section.

Description:
FIELD OF THE INVENTION 
     The invention relates to an improvement to the general type of hot stick device, a representative example of which is disclosed in U.S. Pat. No. 5,593,196, namely, a multi-section telescopic pole for manipulating a tool from a position a selected distance away from a workpiece and, more particularly, to a releasable section locking assembly which includes a pinch safety feature. 
     BACKGROUND OF THE INVENTION 
     Telescopic hot sticks are typically used in a high voltage electrical environment as well as other environments where a long reach is needed to access a workpiece located at a remote location, such as on a power pole or the like. Hot sticks are typically constructed of a suitable dielectric material and include a tool holder at an extremity thereof. The tool holder is adaptable to engage a wide array of different tools or the like. One such hot stick is disclosed in U.S. Pat. No. 5,593,196, the entirety of the disclosure in this patent being incorporated herein by reference. 
     The hot stick disclosed in U.S. Pat. No. 5,593,196 allows a user to perform a wide variety of tasks such as opening and closing various types of switches, replacing fuses, pruning tree limbs or replacing lamps in street circuits and rooms with high ceilings. Since the workpiece may be as far as 30 feet or more away from a user, the telescoping hot stick or pole provide a variable length to accommodate these tasks. 
     One of the issues that arises when the user wishes to extend or collapse the pole sections is that when a digit on the user&#39;s hand is used to depress a button on the locking assembly into the button receiving aperture to move the top surface of the button to a location inside of the inner surface of the outer pole section, sometimes the digit moves the top surface of the button to a position below the outer surface of the inner pole section resulting in the digit on the user&#39;s hand becoming pinched between the outer surface of the inner pole section and the inner surface of the outer pole section. When the user&#39;s hand is covered by a glove, the material of the glove can become caught in the pinch zone. 
     Accordingly, it is a purpose of this invention to provide a telescoping pole assembly which includes a pole locking assembly having a pinch safety feature for preventing the digit on the user&#39;s hand or the material of the user&#39;s glove from becoming pinched between to two mutually adjacent telescoped poles. 
     It is a further object of the invention to provide a telescoping pole assembly wherein the pinch safety feature allows the top surface of the button to be moved from a location radially outside the outer pole section inwardly through the button receiving aperture to a location just inside the inner surface of the outer pole section against a resistance provided by a first elastically yieldable member and against a resiliently yieldable stop. Continued movement of the button radially inwardly can only be continued by the use of a tool or an excessive hand force. This continued movement is against the resistance provided by the first elastically yieldable member combined with the resistance provided by the yieldable stop in the form of a second elastically yieldable member is important for initial assembly purposes to allow a radially inward movement of the top surface of the button to a location radially inside of the inner surface of the inner pole section to enable the locking assembly to be initially inserted into the interior of the inner pole section. 
     SUMMARY OF THE INVENTION 
     The objects and purposes of the invention have been met by providing a multi-section telescoping pole for manipulating a tool from a position a selected distance away from a workpiece and including a tubular first section having a female end and a predetermined shape, the first section having a first aperture and an interior which defines an axial path and has an interior surface which is uniform about a periphery thereof. A second section has a male end slidably engaged within the interior of the first section through the female end and having a second aperture and a predetermined shape corresponding to the shape of the first section and being slidable along the axial path. A pinch safety locking assembly includes a button configured for manual movement of the button by a digit on the user&#39;s hand within aligned first and second apertures from a first position radially outside the outer periphery of the first section radially inwardly against a resistance provided by a first resilient member so that a top surface of the button becomes located at a second location just inside the inner surface of the first section whereat an end of the button remote from the top surface engages an elastically compressible stop having a high compression resistance characteristic to permit relative longitudinal movement between the first and second sections without the digit on the user&#39;s hand becoming pinched. The pinch safety locking assembly is additionally configured to facilitate initial assembly by movement of the top surface of the button by the use of a tool or excessive hand force to a third position just inside the inner surface of the second section against a combined resistance of the first resilient member and the resistance of the elastically compressible stop to permit relative movement between the pinch safety locking assembly and the second section and a sliding of the pinch safety locking assembly along said axial path to a position where the button is aligned with and received in the second aperture. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a broken front elevational view of the telescoping hot stick of the invention illustrated in the fully extended position; 
         FIG. 2  is a broken front elevational view of the telescoping hot stick illustrating a plurality of sections collapsed one within the other; 
         FIG. 3  is a sectional view of cooperating male and female ends of adjacent sections and of a locking assembly illustrated in engagement as viewed in the direction of arrows  3 - 3  of  FIG. 1 ; 
         FIG. 4  is a sectional view similar to  FIG. 3  but with the button of the locking assembly pushed further radially inwardly so that the top surface of the button is located radially inside of the inner surface of the outer tube section; 
         FIG. 5  is a sectional view similar to  FIG. 4  but with the button of the locking assembly pushed further radially inwardly so that the top surface of the button is located radially inside of the inner surface of the inner tube section; 
         FIG. 6  is a sectional view of the sections collapsed one within the other as viewed in the direction of arrows  6 - 6  of  FIG. 2 ; 
         FIG. 7  is a partial perspective view of an extremity of the telescoping hot stick illustrating a tool holder; 
         FIG. 8  is an exploded partial perspective view of the male and female ends of adjacent sections and an exploded sectional view of a locking assembly therebetween; and 
         FIG. 9  is an exploded partial perspective view of the locking assembly being assembled into the inner tube section. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , the telescopic hot stick or pole of the invention is generally designated by reference numeral  10 . The telescoping hot stick  10  includes a predetermined number of similar length, tubular sections  12 , i.e.  12 A- 12 E, slidingly engaged one with the other which provide a variable length for the hot stick  10 , a corresponding number of locking assemblies  14 , i.e.  14 B- 14 E, provided between each adjacent section  12  for securing the adjacent sections  12  in extended engagement, and a tool holder  16  at an extremity  18  thereof. To shorten the overall length of the hot stick  10 , each section  12  is readily removable as described herein. 
     More particularly, to provide telescoping engagement of the sections  12 A- 12 E, the sections  12 A- 12 E are provided with progressively decreasing cross-sectional dimensions as illustrated in  FIG. 6  wherein the first section  12 A has the largest cross-sectional dimension and last section  12 E has the smallest cross-sectional dimension. The sections  12  are tubular and have a close-fit slidingly engaged relation one with the other so that the sections will remain coaxial with little or no detectable relative movement therebetween when in the extended relation. 
     To prevent relative rotation between the sections  12 , sections  12  are formed with a predetermined non-circular cross-sectional shape. Preferably, this shape is substantially triangular as illustrated in  FIG. 6  so as to have three side surfaces with a convex arcuate corner portion disposed between each mutually adjacent pair of side surfaces. It should be recognized that other non-circular shapes may be used, so long as rotation of one section  12  relative to an adjacent section  12  is prevented and sliding engagement is permitted. 
     The cross-sectional shape should be uniform along the axial length of each section  12  to facilitate assembly and disassembly of the hot stick  10 . In other words, there should be no physical constructions which would impede sliding engagement of adjacent sections  12 , e.g.  12 A and  12 B;  12 B and  12 C; etc. 
     The particular length of each section  12 A- 12 E and the total quantity of sections  12  comprising each pole  10  can vary depending upon the overall total length required for the pole  10 . It should be recognized that any combination of lengths and quantity may be used to provide the desired length and satisfy the intended uses of the pole  10 . 
     The sections  12 A- 12 E are constructed of any suitable material which provides the desired strength, color stability and dielectric properties. The preferred material is a reinforced high density electrical grade fiber glass laminate with which a skilled artisan would be familiar. 
     As seen in  FIG. 1 , adjacent sections  12 , i.e.  12 A and  12 B,  12 B and  12 C, etc., are maintained in extended engagement by the particular locking assembly  14  associated therewith. To illustrate the cooperating engagement of these structures, the specific construction of representative sections  12 A and  12 B is described as illustrated in  FIGS. 3 ,  4 ,  5 ,  8  and  9 . It should be recognized, however, that a similar construction is utilized with respect to the engagement of the other adjacent sections  12 B- 12 E illustrated in  FIG. 1 . 
     Referring to  FIG. 8 , the larger first section  12 A includes adjacent a female end  20 , defined by an opening  21 , an aperture  22  therethrough in one surface of the non-circular form. To prevent rotation and facilitate gripping of the outer periphery  24  of the section  12 A by the user, the outer periphery  24  as well as an inner periphery  26  of section  12 A is formed with the substantially same triangular cross-sectional shape. 
     To permit sliding engagement of the section  12 B within the adjacent section  12 A, the section  12 B has a male end  28  which has an outer periphery  30  conforming in a close-fit relation to the inner periphery  26  of the female end  20 . A typical clearance between an inner peripheral surface  26  and an outer peripheral surface  28  of each of the telescoping sections is in the range of 0.012 to 0.016 inches which is also sufficient to prevent entrapment of air. To accomplish locking engagement of the section  12 B with the section  12 A, the male end  28  includes an aperture  32  extending therethrough. The aperture  32  is positioned adjacent to a terminal end part of the male part  28  and dimensioned so as to permit alignment of the aperture  32  with the aperture  22  of the section  12 A. Accordingly, the extended position of the section  12 B, as illustrated in  FIG. 1 , is defined by the relative positions of the sections  12 A and  12 B when the apertures  22  and  32  are in registry. 
     To lock the male end  28  in engagement with the female end  20  and maintain the section  12 B in the extended position, the locking assembly  14 B is provided on the section  12 B as seen in  FIG. 8 . The locking assembly  14 B includes an end wall portion  34  and a mounting section  36  which are formed of a polymer or any other suitable material. The mounting section  36  is formed with an outer periphery  38  having a cross-sectional shape and outer dimension conforming in a close-fit relation to an inner peripheral surface  40  of the male end  28  so as to permit insertion of the mounting section  36  within the male end  28 . To limit the extent of insertion of the mounting section  36  therein, the end wall portion  34  is dimensioned so as to form an annular flange  42  which extends radially outward so as to be flush with the outer periphery  30  of the mounting section  36 . 
     The annular flange  42  abuts against an end face  44  of the male end  28  when the locking assembly  14 B is fully inserted therein to close off the male end  28 . 
     The locking assemblies  14 B- 14 E are each secured inside the respective males end of each section  12 B- 12 E, respectively, by any conventional and conveniently available means. 
     To lock the male end  28  with the female end  20  in the extended position, a spring biased button  54  seats within a pocket  56  formed within the locking assembly  14 A. To engage the male end  28  with the female end  20  when the apertures  22  and  32  are in registry, the button  54  has an outer peripheral dimension and shape which is substantially identical to the peripheral dimensions and shape of the apertures  22  and  32  such that the button  54  extends therethrough and prevents relative movement of the adjacent sections  12 A and  12 B. 
     To maintain the button  54  in an extended locking position illustrated in  FIG. 3 , a spring  58  is retained between a spring seat  60  in the pocket  56  and an opposing spring seat  62  formed on the button  54 . To keep the button  54  within the pocket  56  when the locking assembly  14  is secured within the male end  28 , outwardly extending flanges  64  illustrated in  FIG. 5  are provided on the button  54 . The flanges  64  are stepped so as to contact the inner periphery  40  of the male end  28  when the button  54  is extended as seen in  FIG. 3 . 
     In the device shown in the aforementioned U.S. Pat. No. 5,593,196 which is incorporated herein by reference, it periodically occurs that the digit on the user&#39;s hand manually urging the button radially inwardly against the urging of the spring  58  would become pinched between the mutually adjacent axially oppositely facing edges of the apertures  22  and  32  when the sections  12 A and  12  were moved axially relative to one another. If the user was wearing a glove at the time, the material of the glove would become snagged between the aforesaid mutually facing edges of the apertures in the respective sections  12 A and  12 B. In order to prevent the pinching from occurring, we have provided a pinch safety feature which includes the provision of an elastically compressible O-ring  70  having a preselected cross-sectional diameter in the pocket  56  and configured to rest on the bottom wall  71  of the pocket as shown in  FIGS. 3-5 . The cross-sectional diameter D ( FIG. 8 ) of the O-ring  70  is preselected to engage the bottom surface  72  of the button  54  when the button is urged by the digit on the user&#39;s hand radially inwardly to the position where the upper surface  73  of the button becomes located just inside the inner surface  40  of the outer section  12 A as shown in  FIG. 4 . The O-ring  70  serves to provide a tactile indication to the user of restriction to further movement of the button radially inwardly by the digit on the user&#39;s hand and, since the upper surface  73  of the button  70  is located just inside the inner surface  40 , the resulting gap between the outer surface of the section  12 B and the inner surface of the outer section  12 A is much smaller than the user&#39;s finger to thereby prevent the digit on the user&#39;s hand from becoming pinched between the mutually adjacent axially oppositely facing edges of the apertures  22  and  32  when the adjacent sections are moved axially with respect to one another. To move the button  54  further radially inwardly from the position illustrated in  FIG. 4  would require a much greater force than can be provided by the digit on the user&#39;s hand. In this particular embodiment, the O-ring  70  is made of an elastically compressible polymer, such as rubber or equivalent, having a resistance to compression that is tactilely noticeably greater than the resistance to compression of the spring  58 . 
     In order to assemble the locking assemblies  14 , i.e.,  14 B- 14 E, into the respective sections  12 B- 12 E, the upper surface  73  of the respective button  54  is required to be moved radially inwardly with the assistance of a tool schematically represented by the reference T in  FIG. 9  or an excessive hand force against the combined resistance of the spring  58  and the elastically compressible O-ring  70  to just inside the outer periphery of the section into which it is being installed (illustrative example shown in  FIGS. 5 and 9 ) so that the respective locking assembly can be slid along the axial path until the button becomes aligned with the respective aperture  32  at which time the button is urged radially outwardly through the aperture  32  by the resilience of the resilient members  58  and  70 . Thereafter, to disengage the button  54  from the apertures  22  and  32  and permit removal and/or relative telescoping sliding of the male end  28  with respect to the female end  20 , a user may actuate the button  54  to a depressed position where the user will note the tactile sensation of resistance provided by the O-ring  70 . During sliding of section  12 B, the button  54  remains in the depressed position either until the apertures  22  and  32  are in registry and the button  54  is biased upwardly by the spring  58  or until the section  12 B is removed completely from section  12 A. 
     It is to be understood that a second compression spring (not shown) can be used in place of the O-ring  70 , such as providing the second spring inside (or outside) of the spring  58 . Further, a dual rate spring could be used in place of the combined single rate spring  58  and O-ring  70 . It is also understood that other forms of elastomers such as a short section of tubing could be used in place of the O-ring. 
     Although particular preferred embodiments of the invention have been disclosed in detail for illustrative purposes to demonstrate the improvement over known constructions, it will be recognized that variations or modifications of the disclosed apparatus of the invention, including the rearrangement of parts, lie within the scope of the present invention.