US2291593A

US2291593A - Operating tool for high tension electric lines

Info

Publication number: US2291593A
Application number: US406665A
Authority: US
Inventors: David C Hubbard
Original assignee: AB Chance Co
Current assignee: AB Chance Co
Priority date: 1941-08-13
Filing date: 1941-08-13
Publication date: 1942-07-28
Anticipated expiration: 1959-07-28

Description

J'uly 28, 1942. D. C. HUBBRD 2 OPERATING Tool. FOR lHIGH TENsioN ELECTRIC -LINES.

Filed Aug. 13, 1.941

2 Sheets-'Sheet 1 July 2s, 1942. 2,291,593 OPERATING TOOL FOR II-IGl-I'TENSION` ELECTRIC LINES D. c. HUBBARD Filed Aug. 13, 1941 2 Sheets-Shea?I 2 Patented July 128, `1942 OPERATING TOOL FOB BEIGE TENSION ELECTRIC LINES David C. Hubbard, Centralia, Mo., assigner to A. B. Chance Company, Centralia, Mo., a corporation o! Missouri Application August 13, 1941, Serial No. 406,665

11 Claims. ('Cl. 294-19) The present invention relates to operating tools for high tension electric lines, and is particularly concerned with telescoping insulating sticks adapted to be used for supporting disconnects and various other types of tools or for use in measuring distances. x

One of the objects of the invention is the provision of an improved telescoping disconnect stick I which is adapted to be used for handling blade disconnects or fused cutouts of any style, and which is of light weight and collapsible, to be packed in a very limited space.

Another object of the invention is the provision of an improved telescoping insulating stick ofthe class described, which has a highmechanical and dielectric strength, a low moisture absorption, and which is adequately insulated so that it may be used on high tension circuits.

Another object of the invention is the provision of an improved telescoping insulating stick having an improved latching arrangement, all of the exposed parts of which may be made of insulating materials, and by means of which any or all of the sections may be latched in the extended' position.

Another object of the invention is the provision of an improved telescoping insulating stick which is provided with an improved structure for preventing rotative motion between the various sections of the stick so that it may be used for exerting a relatively strong torque.

Another object of the invention is the provision of improved forms of latching mechanism vention,v embodied in a disconnect stick, with its parts in collapsed position;

Fig. 2 is a side elevational view of the same disconnect stick, with the sections fully extended;

Fig. 3 is a transverse sectional view, taken on a plane passing through the axis of the stick and through the axes of the latches, showing the details of construction of the invention;

Fig. iis a transverse sectional view, taken on the plane of the line-4 4 of Fig. 3;

Fig.v 5 is a fragmentary sectional view, taken on the same plane as Fig. 3, with the interlocking sleeves of two sections shown in elevation;

Fig. 6 is a transverse sectional View, taken on the plane of the line 6-6 of Fig. 5, looking in the direction of the arrows;

Fig. 'I is a fragmentary elevational view in partial sectiOn, showing an alternative form of head for the stick;

for telescoping disconnect sticks or tools by means of which the sections may be secured in extended position or they may be collapsed at will.

Another object of the invention is the provision of an improved telescoping insulating stick adapted to be used for measuring the height or spacing of conductors.

Another object of the invention is the provision of an improved telescoping insulating stick adapted to be used with a universal' head so that it is available for connection to a multiplicity of diierent types of tools and which is also provided `with automatic latching means for latching the sections in extended position.

` Other objects of the invention will be apparent fromthe following description and the accompanying drawings, in which similar characters of reference indicate similar parts throughout the several views. f

Referring to the 'two sheets of drawings,

Fig 1 is an elevational view of the telescoping insulating stick constructed according to the in- Fig. 8 is an elevational view similar'to Fig. v'7, showing a similar stick provided with a universal head for attachment to various dierent types of tools and at various angles; Fig. 9 isa view similar to Fig. 1 of a modication comprising a multiplicity of extensible sections in a stick of the class adapted to be used for measuring the length of conductors;

Fig. 10 is a fragmentary longitudinal sectional view of another form of latching mechanism adapted tobe used in the embodiments of Fig. 1 l

or Fig. 8;

Fig. 11 is a transverse sectional view, taken on the plane of the line lI-ll of Fig. 10, looking in the direction of the arrows;

Fig. 12 is a sectional view taken on the line I2'|2 of Fig. l0, looking in the direction of the arrows;

Fig. 13 is a fragmentary elevational view of one l of the Joints ofthe type utilized in the insulating sticks vof Fig. 9 which are, also illustrated in'section in Fig. 10.

. Referring to Figs. 1 to 3, 20 indicates in its entirety the tool shown in this embodiment of the invention; comprising a disconnect stick. This `disconnect stick includes the three

sections

2l, 22, and 23; but it should be understood that any number of sections of similar lconstruction may be included, and the length is limited only by the strength of the materials used, and the size of the largest section, which is preferably of 'suitable size to be used as a handle.

The disconnect stick is shown in extended position in Flg.- 2, and collapsed or partially collapsed in Fis. 1.

The sections 2l-23 are allpreferably made of insulating material, there being no metal cept the metal iltting at the end. and the metal springs used in the latches of this embodiment.

I'he tubing is preferably a canvas base, laminated plastic tubing, having a low rate of moisture absorption and a high mechanical strength. In some embodiments of the invention the tubing may comprise tubes; of indurated iiben 'I'he section 23 ing tube 24 of suitable length to form one Section of the stick, and at its lower end this tube is preferably provided with an insulating closure 25, such as a wooden plug, having a reduced cylindrical portion 25 fitting in the tube, and having an annular shoulder 21 fitting against the end of the tube.

The plug 25 may have its external'surface 29 of partially spherical form, and it may have a tight frictional Vllt in the end of the tube 24, and may be secured in addition by means of an insulating pin 29 driven into an aperture in preferably comprises an insulatthe plug and apertures in the walls of the tube 24.

The hole 30 in the tube 24 is for the admission or egress of air during the extension or collapse of the sectional stick. The break 3| in the tube indicates that the tube is of greater length than that shown in` the drawings (Fig. 3) and the length of one section is determined by the convenient length for the collapsed stick, which should preferably be such that the stick can be carried behind the seat of a small business coupe or in theA trunk of an automobile.

At its opposite end, `that is, the left end of the tube 24 in Fig. 3, this tube is provided with an interlocking sleeve 32, which may consist of a short length of tube of the same material, having its left end cut 01T squarely and its right end formed with two squarely cut

portions

33, 34, separated by two axially extending shoulders 35.

This is best illustrated in Fig. 5, Where the interlocking sleeve 32 is seen in partial elevation. The interlocking sleeve 32 is fixedly secured to the tube 24 by means of a plurality of transverse pins 36, which have a tight frictional t in a suitable aperture 31 in the tube 24 and sleeve 32.

In addition, the sleeve 32 may have a tight frictional fit inside the tube 24, where it is secured with the ends of the sleeve and tube ilush at the right end of the sleeve 23. section 22 preferably comprises another insulating tube 38 of the same material and a size that it has a sliding movement inside the sleeve 32.

The tube 38 is provided on its right end, lthat is, the end which is located in the section 23, with an interlocking sleeve 39, shown in partial elevation in Fig. 5.

Interlocking sleeve 39 comprises an insulating sleeve, which may be of the same material as the

tubes

24, 38, 32, and it is secured on the right end of the tube 38 (Fig. 3) with which it has a tight frictional t.

The right end of this interlocking sleeve 39 may again be cut oil? squarely, but its left end is provided with two squarely cut portions, indicated at 49, 4|, separated by two axially extending shoulders 42.

The offset between the surfaces 40 and 4| is the same as that between the

surfaces

33 and 34 of the interlocking sleeve 32. The sleeve 39 The next of such I may be further flxedly secured to the tube 38 l ,versely extending tube 41 1 32 and 39, so

turesin the tube 33, sleeve 39, and in a cylindrical wooden plug 44. All of these parts preferably have a tight frictional it with each other.

It will be apparent -that when the tube 33 has a proper rotational position with respect to the tube 24, the

sleeves

32 and 39 may beybrought into interlocking relation with each other so that the axial shoulders 35 engage the axial shoulders 42 and rotation is prevented between these

tubes

39 and 24.

I'he wooden plug 44 in the section 22 is preferably of sufficient length to 'extend from the right end of the interlocking sleeve 39 beyond the interlocking sleeve 32 of the section 23 so that itmay also provide a support for a latching member 45, shown in Eig. 3 as a spring pressed plunger. M

At a point Just beyond the end of the tube 24 of the first section 23, when thesecond section 22 is fully extended and the interlocking

shoulders

35 and 42 are engaging each other, the tube 38 and plug 44 are provided with a through bore 46. Wherever transverse pins, frietionally secured in apertures, are described. pins, rivets or screws may be employed.

This through bore may `be lined with a transof the same insulating material as the

tubes

24 and 39, and tube 41 comprises a guide for the plungers 45. 49.

These plungers or latching members may be identical in construction, and each preferably comprises a substantially cylindrical insulating member 45, 48 lof ber, Bakelite,A or wood, having a sliding fit in the tube 41. One corner of each of these latches or dogs 45, 49 is preferably beveled as at 49 sulciently so that the beveled camming surface 49 will engage the inside of the interlocking sleeve 32 and cam the plungers inwardly when the plungers are disposed in the tube 24 beyond the sleeve 32.

In order to limit the outward movement of the dogs 45, 49, they are preferably provided with through bores 50 extending at right angles to the axis and located near the inner end for receiving the cylindrical insulating pin 5|,.which has a tight frictional fit in the 'bore 50.

The pin 5| is of sufficient length to extend into the slot 52 in one or both sides of the tube 41, in which th'e pin is slidably mounted for movement w1th the plunger. 'I'he pins 5| prevent rotation of the plungers, and they are so located that the beveled surface 49 is located just outside the tube 39.

The two plungers vv45, 48 may be outwardly pressed by means of a helical coil spring 53 located in the tube 41. This is the only part oi' the latching assembly which is made`of metal. The compression spring 53 may be made of any suitable material, such' as spring wire, brass, or bronze, or steel. At its opposite end, that is, the left end in Fig. 3, the section 22 is similar in construction to the same end of the section 23, previously described.

The other section 22 has an interlocking sleeve 32 fixed in the tube 39 to engage the interlocking sleeve 39 carried yby the tube 54 of section 2|.

Section 2| has its right end of a construction which is exactly similar to the right end of the section 22, except that the tube 54 is' of smaller proportions, and so are th'e interlocking sleeves that tube 54 slides inside the interlocking sleeve 32 of tube 39. In the same way the tubularguide 48 of section 2| is be shorter,

`41 for the latching dogs 45,

-54 and plug 55.` `prises -a substantially cyhndrical pin, providedparts'svrnaller, so thatit may slide in thenext bigger. section.' Y

As previously stated, any number of sections.

may be employed. The endrnost section 2| may have the open end of its tube 54 closed by an insulating plug' 55 of wood or other suitable insulating matriel, such as fiber, or amoided phenolic condensation compound, such as Bake- 1ite."

This insulating. plug has a cylindrical. portion 56, which itsinside the tube 54, and has an annular shoulder engaging the end of the tube. Theouter end 58 of the plug 55 may be partially spherical, and theplirg has a frictional t in the tube 54'.

It is, however, vpreferably secured in place'by means of the disconnect, pin 5 9, Which passes through the through bores 60 in the tube The disconnect pin 59 comwith a .cylindrical head 6I carried by the cylindrical shank 62. The pin is preferably canvas base phenolicmaterial.

f -The head 6l may be chamfered at .63', giving it a tapered outermost portion, which is more easily inserted -into an aperture of fa .cover or a disconnect.v The .shank 62 is secured in the bore 60 by means of a transverse pin- 64, which may be 'off insulating fiber or metal, and the, transf pin '64; hasjartight frictional fit .in the dis- Refer-ring to'Fg: 7, this-is a fragmentary ele- 1 vaticani viewf v of head forthe end ofthe tool. In this case the .end assembly comprises a metal member 65, hav

in partial sectionof another form ing a cylindrical portion 66 fitting in the. end of the tube 54, and having an annular shoulder 61:

engaging the end. The .cylindrical portion 66 'is secured m place by` a; transverse headless rivet 68, which passes I through. the cylindrical portion 66 and. tube 54.

The fittingv65 has a cylindrical shank 69 .provided with a conically pointed end portionl. The cylindrical shank 10' has a transversely extending arm 1I at right angles to the shank 69,

and preferably of smaller size, and the arm 1I j 11 for receiving the wing nut 18. The face 19 c of the universal head 80 toward the head of the .3 shank 66v 'of cylindrical shape adapted'to fit in a tube 54, andwith an annular shoulder .61 so that 'itis secured to the stick in the same Amanner'v as `shown in Fig. 7.

The4 universal head has la substantially circular ange 16 carried lby the shank 6 6, and having a centrally located threaded through aperture bolt 18 is provided with a plurality of regularly spaced lugs 8l. arranged in a circle and separated by slots of the same width as the lugs 8l. Thus -this universal head is adapted to be attached to any of a multiplicity of tools, with the tool at various angles', the tool having a circular fiange similar to the ange 16, except that it has a slot instead ofv anaperture 11.'

The -wing nut 18 and lugs 8| serve to secure the tool in any of a'plurality. of angular positions. l-

Among'the. tools which may be used on the end of a stick provided with such a universal head are clamp stick heads, wrenches, wire tong heads, tie stick heads, fork heads, ratchet wrench heads, cotter key removerl and replacer, cotter key puller,.locating pins, chuck blanks, fuse pullmay `be tapered toward itsouter end portion,`

Where-it is provided with a circular head 12. The circularhead has an abrupt shoulder 13 on its inner side, and it is tapered around itat 14, near its outer face 15.

The taperedbr rounded surface 14 is adapted to facilitate the entry of the head 12 into a hole in a cover or disconnect. The abrupt shoulder 13 is adapted to retain the-arm 1| in such a hole.

The axially extending shank 69 in combination with the transverse arm .1I is useful in pushing members connected with a transmission line, and the tapered or conical point. 10 serves to permit the shank 69 to Vbe inserted in apertures more readily.

.In addition to the tight frictional fit between the closure plugs, rivet pins, interlocking sleeves,

and tubes, these members'may be cemented in extended length of the stick.

place wherever they are supposed-to bev xedly secured to another member.

It should be understood that wherever a tight frictional fit is specified forA fixed' securement,

cement may also be employed-and the cement is preferably of aninsulating character.

ers, screw drivers, insulation knife, paint brushes.

insulator brushes, Ifolding rules, bolt headers, ball mirrors, hack saws, pruning'.

socket adjusters',v

saws,etc. v

Referring to Fig, 9, thisisan elevational view similar to Fig.v 1 of ameasuring stickoffsimilar construction, having its sections made of a plu-r rality of telescoping-tubes, according tothe con? struction shownin Fig. 3 or l0. For example, such a measuring stick, including nine sections,

-each of which extends to about three feet, makes a 27 ft. insulating rod for measuring conductor heights. The sections can be provided with foot and inch markings', printed or painted on the sections, but the tubes are preferably not weakened by any marking grooves, since that would have an undesirable` weakening effect on the. stick .when extended. v

Such a measuring stick will readily indicate the length by the extension of a predetermined number of its sections and the distance .between the end of a multiplicity of extended sectionsv and the conductor to be measured, can readily be determined by the use of a rule, and added to the Referring to Fig. 10,v this is ausectional view, showing another form of latching mechanism for extensible Sticks of the type shown in Fig. l or Fig. 9.

In this' casethe. same latching mechanism may be used at the joints between all of the various sections. The ends of the endmost sections may beclosed by means vof an insulating plug similar to that shown at 25v in Fig. 3.

The sections are made ofinsulating tubes of the same material, previously described, and each successive section is made of tubes of the next smaller size, adapted to slide or telescope into the preceding section. v

As all of the joints and latching mechanisms are similar, only one 'need be described in detail.'

In Fig. 10, 82 indicates the en d of the. larger of vReferring to Fig. 8, this vis a view similar to Y.

Fig. '1, showing a universal head'for use on the insulating stick of Fignlfor Fig. 9. This universal head is of the type having a securing two sections, and 83 indicates the adj'acent end of thesmaller of two sections.

f T he insulating tube a3 is.-c1os`ed by eens of an insulating cylindrical wooden plug 84, having a tight frictional iitin the end of the tube 83, and also secured'iby means of a transverse insulating mented in place.

' chute 98.

' ing button 89, the button to prevent relative rotation between -for tools of var ious types.

pin 85. Both the pin 85 and plug 84 may be ce- At a point spaced from the end of the tube 83, the plug 84 is provided with a transverse cylindrical bore 86, and the tube 83 is provided with a smaller counterbore 81. 'I'he counter-bore 81 is adapted to receive the cylindrical body 88 of alatching button 89. A circular head 98 on the latching button 89 is received in the bore 88, and the head limits the outward movement of the button.

A helical'compression spring 9| is located in the bore 86 and engages the heads 9| of two of the buttons 89, to urge them outward. Each button 89 preferably has the end of its body 88 pro,-

' vided with a rounded, tapered, or partially spherical surface 92, to aid in bringing about the retraction of the button by camming action.

The larger tube 82 is provided on its end, surrounding the. tube 83, with a cylindrical ferrule 93 of the same insulating material, having a tight frictional ilt about the tube 82 and secured in place by cement and by means of a plurality of through pins 9| of insulating material.

Theferrule 93 has a radially inwardly extending annular flange 95, which is provided with a circular aperture 96 tube 83.

'Ihe ange 95 is spaced from the end surface 91 of the t`ube 82 suiliciently to provide space for the latching button or pin 89.

, At two diametrically opposite points the insulating tube 82 is provided with the tapered slots k98, adapted to engage the rounded end 92 of the latching button 89 and to cam the button inward when the buttons are in registry with the slots 98 and the two each other in such manner as to telescope the section 83 into section 82.

In some embodiments of the invention the space between the end 91`and ilan'ge 95 may be an annular groove so that the sections are not secured against rotation relative to each other, but are'secured against collapse when each latching button 89 is rotated away from its release In other embodiments of the invention the inner tube 82 may have axially extending shoulders in the annular groove which receives the latchthe annular shoulders engaging the sections. In such case used to'exert a torsion or well as a pull or push.

The latching mechanisms of Fig. 10 may.be used in the telescoping stick of Figs. 4l to 3 or that of Fig. 9.

the sections can be a twist onv a tool, as

for slidably receiving the sections are pushed toward It will thus be observed that I have invented a j telescoping tool for use on live transmission lines,

" which isv adapted to be collapsed to a minimum length or extended to provide an insulating pole All of the exposed parts of the telescoping stick or pole are made of insulating material, and the stick is adapted to have a high insulating value.' It has a high mechanical strength and may be used with various types of tools for transmitting torsion, push, or pull, or combinations of these forces upon the tool and the devices on which the tool works. I have found that the mechanical strength of the stick is high enough to use on hot wire clamps of all kinds and on varioustypes of tools customarily employed on the end of a wooden or other insulating stick.

While I have illustrated a preferred embodiinside, adjacent the tion between the llarger of said ment of my invention, many modications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of constructionA set forth, but desire to avail myself of all changes within the scope of the appended claims.

Having thus described-.my invention, what I claim as new and desire to secure by LettersPatent of the United States is:

l. In a telescoping'tool for high tension lines, the combination oi' a pair of telescoping sections, each of said sections comprising insulating tube, and one section sliding within the larger of said sections being provided on its inside, adjacent the Joint .between said sections, with an interlocking sleeve iixedly secured to said larger section,vand adapted to slidably receive the smaller of said sections, and a similar interlocking sleeve carried by the smaller section and xedly secured to the smaller section inside the larger section to determine the extended position of said sections.

2. In a telescoping tool for the combination of a pair of telescoping sections, each of said sections comprising insulating tube, and one section sliding within the other, the larger of said sections being provided on its inside, adjacent the joint between said sections, with an interlocking sleeve xedly secured to said larger section, and adapted to slidablyreceive the smaller of said sections, and a similar interloclcing sleeve carried by the smaller section and xedly secured to the smaller section inside the larger section to determine the extended position of said sections, said interlocking sleeves being secured to the tubular sections by means of transverse securing means located in apertures in the sleeves and tube 3. In a telescoping tool for high tension lines. the combination of apair of telescoping sections, each of said tube, and one section sliding within the other, the larger of said sections being provided'on its joint between said sections. with an interlocking sleeve xedly secured to said larger section, and adapted to slidably receive the smaller of said sections, and a similar interhigh tension lines,

locking sleeve carried by the smaller section and to the smaller section inside they provided with axially extending shoulders engaging each other and preventing the-relative rotasections in Onedirection.

4. In a telescoping tool forhlgh tension'lines. the combination of a pair of telescoping section s, each of said sections comprising insulating tube, and one section sliding within"the other, the

` sections being provided on its inside, adjacent the-joint between said sections. with an interlocking sleeve iixedly secured to said larger section, and adapted to slidably receive the smaller ofsaid sections, and a similar interlocking sleeve carriedby the iixedly secured to the smaller section inside the larger section to determine the extended -position of said sections, said interlocking sleeves being provided with axially extending portions and recesses fitting within each other whereby relative rotation between the .sections is prevented in either direction. g

5. In a telescoping tool for high tension lines, the combination of a pair of telescoping sections, each of said sectionsv comprising insulating tube, and one section sliding within the other, the

other, the

sections comprising insulating smaller section and the combination of a pair of larger of said sections being provided on its inside-adjacent the joint between said sections. with an interlocking sleeve iixedly secured to said larger section, and adapted to slidably receive the smaller oi said sections, and a similar interlocking sleeve carried by the smaller section Vand flxedly secured to the smaller section inside the larger section to determine the extended position of said sections, said smallerA section having a radially projecting latching member located to engage the end of the larger section when said sections are extended.

6. In a telescoping tool for high tension lines, the combination-of a pair of telescoping sections, each of said section-s comprising insulating tube, and one section sliding within the other,'the larger of said sections being provided on its inside, adjacent the joint between said sections, with an interlocking sleeve xedly secured to said larger section, and adapted to slidably receive the smaller of said sections, and a similar interlocking sleeve carried by the smaller section and ixedly secured to the smaller section inside the larger section to determine the extended position of said sections, said smaller section having a radially projecting latching member located to engage the end of the larger section when said sections are extended, and vresilient means urging said latching member into latching position.

'7. In a telescoping tool for high tension lines, the combination of a pair of telescoping sections, each of said sections comprising insulating tube, and one section sliding within the other, the larger of said sections being provided on its inside, adjacent the joint between said sections, with an interlocking sleeve xedly Isecured to said larger section, and adapted to slidably receive the smaller of said sections, and a similar interlocking sleeve carried by larger section to tion of said sections, said-smaller section having a radiallyl projecting latching member located to engage the end of the largersection when said sections are extended, said latching member being slidably mounted in a transverse tubular guide.

8. In a telescoping tool for high tensionl lines, telescoping sections, each of said sections comprising insulating tube, and one section sliding within the othe the larger of said sections being provided on its inside, adjacent the joint between said sections, with an interlocking sleeve xedly secured to said larger section, and adapted to slidably receive the l smaller of said sections, and a similar interlocking sleeve carried by the smaller section and xedly secured to the smaller section inside the larger section to determine the extended position of said sections, said smaller section having a radially projecting latching member located to engage the end of the larger section when said the smaller section and iixedly secured to the smaller section inside the determine the extended position of said sections,

of successively sections are extended, said latching member being slidably mounted in a transverse tubular guide, and said latching member having a transversely extending pin for limiting its outward movement.

9. In a telescoping tool for high tension lines, the combination of a pair of telescoping sec tions, each of said sections comprising insulating tube, and one section sliding within the other, the larger of said sections being provided on its inside, adjacent the joint between said sections, with an interlocking sleeve flxedly secured to said larger section, and adapted to slidably receive the'smaller of said sections, and a similar interlocking sleeve carried by the smaller-section and fixedly' secured tothe smaller section inside the larger section to determine the extended posisaid smaller section having a radially projecting latching member located to engage the end of the larger section when said sections are extended, said latching member being slidably mounted in a transverse tubular guide, and said latching member having a transversely extending pin for limiting its outward movement, said guide having a slot for receiving said pin to prevent rotation of said latching member.

10. In a telescoping insulating stick for manipseries, with latching means of insulating material operating between said sectionsfor securing said sections in-extendedposition, and insulating means carried by the sections for preventing relative rotation between the successive sections, and an electrical tool carried by one of the insulating stick and adapted to be actuated in a rotary or longitudinal direction by said stick.

11. In a telescoping insulating stick ofvmanipulation of energized equipment by means oi' the application of rotationor a push or pull, the combination of a plurality of tubular sections of electrical insulating material, said sections being smaller size, and said sections being slidably mounted with respect to each other in a series, means for closing the endmost sections of said stick including an electricalv tool carried by an end of the insulting stick and adapted to be yactuated in a rotary or longitudinal direction by said stick, and insulating means carried by said sections and located at the ends of the sections where relative sliding movement occurs, comprising an insulating. vmember 1ocated inside the end portion of, the section and adapted to engage a part carried by the end of ,the larger section to prevent and rotative movement between the sections.

DAVID C. HUBBARD.

relative longitudinal