US3197036A - Powered combination elevating ladder and crane hoist - Google Patents

Description

July 27, 1965 P. A. MASON 3,197,036

POWERED COMBINATION ELEVATING LADDER AND CRANE HOIST Filed Jan. 15, 1964 3 Sheets-Sheet 1 L E 1 Z INVENTOR.

Paul A. Mason A f forney.

July 27, 1965 P. A. MASON 3,197,036

POWERED COMBINATION ELEVATING LADDER AND CRANE HOIST Fw/ A. Mann Affvrney.

July 27, 1965 P. A. MASON 3,197,036

POWERED COMBINATION ELEVATING LADDER AND CRANE HOIST Filed Jan. 13, 1964 3 Sheets-Sheet 5 My. 9 INVENTOR.

BY 3 mm United States Patent 3,197,036 POWERED COMBINATION ELEVATING LADDER AND CRANE HOIST Paul A. Mason, Phillipsburg, Kans. Filed Jan. 13, 1964, Ser. No. 337,486 14 Claims. (Ci. 212-8) This invention relates to new and useful improvements in elevating ladder and hoisting equipment, and has as its principal object the provision of a device which may be used selectively either as an elevating ladder or as a crane hoist. In carrying out this object, the basic elements of my invention are a vertical standard having a boom pivoted intermediate its ends to the upper end thereof, said boom being tiltable by novel power means to elevate either end thereof, and being longitudinally adjustable relative to its pivotal support to extend either end thereof to a substantial distance from the standard. One end of the boom carries a support which, when that end of the boom is extended, supports an elongated ladder or other high-lift load arm, which is then elevatable from a horizontal to a steeply inclined position by operation of the boom. The other end of the boom carries a hoist apparatus such that when that end of the boom is extended, it may serve as a crane-type hoist.

Another object is the provision of a device of the character described wherein the boom may be rotated a full 360 degrees about the vertical axis of the standard, for greater flexibility in positioning the ladder or the hoist, and rigidly fixed at any desired angular position.

A further object is the provision of a device of the character described wherein a single power unit, namely a fluid-actuated ram, serves selectively to elevate either end of the boom.

A still further object is the provision of a device of the character described which may conveniently be installed an used in a pick-up truck or the like, but which nevertheless may be easily removed for use elsewhere, the entire device being supported on a wheel cart secured to the truck bed or to any other suitable base only by a pair of bolts.

Other objects are simplicity and economy of construc tion, elficiency and dependability of operation, and adaptability for use in a wide variety of applications.

With these objects in view, as well as other objects which will appear in the course of the specification, reference will be had to the accompanying drawing, wherein:

FIG. 1 is a side elevational view of a combination ladder and hoist embodying the present invention, shown mounted on a pick-up truck, the device being shown adjusted for use of the ladder, said ladder being shown in its horizontal transport position in solid lines and in an inclined position in dotted lines,

FIG. 2 is an enlarged sectional view taken on line II-II of FIG. 1,

FIG. 3 is a fragmentary sectional view taken on line IIIIII of FIG. 2,

FIG. 4 is an enlarged fragmentary sectional view taken on line IV-lV of FIG. 1,

FIG. 5 is an enlarged fragmentary sectional view taken on line VV of FIG. 1, with the hoist links engaged and with parts left in elevation and partially broken away,

FIG. 6 is a fragmentary sectional view taken on line VI-Vl of FIG. 5, with both the hoist links and the ladder links connected, with parts broken away,

FIG. 7 is a fragmentary sectional view taken on line VIIV1I. of FIG. 5, with parts left in elevation,

FIG. 8 is a sectional view taken on line VIII-VIII of FIG. 5,

3,197,635 Patented July 27, 1965 FIG. 9 is a view similar to FIG. 1, but showing the device adjusted for use of the crane hoist, said crane being shown in its horizontal transport positron in solid lines and in an elevated position in dotted lines,

FIG. 10 is an enlarged sectional view taken on hne XX of FIG. 9, with parts omitted, and

FIG. 11 is a fragmentary sectional view taken on line Xl-XI of P16. 10.

Like reference numerals apply to similar parts throughout the several views, and the numeral 2 applies generally to a pick-up truck including a cab 4 and a bed 6 having a floor 8 and side Walls 10. The device forming the subject matter of the present invention includes a cart 12 adapted to be secured to bed 6, preferably at one side thereof, and comprising a vertical planar wall 14 and a horizontal planar base 16 afiixed to and extending outwardly from said wall. Base 16 is supported above truck floor 6, whereby to form a chamber 18 therebetween (see FIGS. 5 and 7), by the engagement of the lower edge of wall 14 with said floor, and by a peripheral side wall 20 afiixed to and depending from base 16. The cart is provided with a wheel 22 at each of the lower corners of wall 14, said wheels being coaxial on a horizontal .axis, and positioned so as to allow the cart to rest firmly on the truck floor, but to support the cart for easy transportation when said cart is tilted, for a purpose which will presently appear. The cart is normally secured rigidly in the truck by a pair of bolts 24 (see FIGS. 4 and 5) passing through floor 8 and cart base 16, and secured by wingnuts 26 above said base.

Disposed above base 16 is an upwardly opening socket 28 having a vertical axis, said socket being supported for axial rotation by a vertical shaft 30 secured to the bottom thereof and extending downwardly through a ball thrust bearing 32 afiixed to base 16 and thence through said base into chamber 18. A sprocket wheel 34 aflixed on the lower end of said shaft is operably connected by a sprocket chain 36 to a sprocket wheel 38 mounted in a vertical shaft 40 journalled in base 16, said shaft having a crank 42 aflixed thereto above said base. By turning said crank, socket 28 may be rotated, the ratio of sprocket wheels 34 and 38 providing a considerable mechanical advantage. Power means such as a motor or fluid ram could be provided for rotating socket 28 if desired, within the scope of the invention. A pair of eye members 44 and 46 are welded or otherwise aflixed respectively to diametrically opposite sides of socket 28, for a purpose which will presently be described.

Socket 28 supports a fluid-actuated ram 48, either air or hydraulic, which serves as a standard supporting the ladder and hoist structure as will be described. Said ram includes a cylinder 50 and a tubular piston rod 52 operable thereinand extendable upwardly therefrom. The closed lower end of cylinder 50 is seated in socket 28, and secured therein by set screw 54 to insure that said cylinder will turn with said socket when said socket is turned by crank 42. Said cylinder is also supported by a pair of spaced apart retainer rings 56 disposed above socket 28, said rings being welded to the upright wall 14 of cart 12. The cylinder may be secured against rotation in said retainer rings by set screws 58, although said set screws must of course be loosened when it is desired to rotate the cylinder.

Piston rod 52 is provided at its lower end with a piston 60 having sealed sliding engagementwith the cylinder wall, and a tubular bushing 62 is afiixed in the upper end of the cylinder so as to have sealed sliding engagement with the piston rod. In order to provide good bending strength for the piston rod when extended, it is made with as large a diameter as practical, leaving only a narrow annular space 64 between the piston and cylinder. A suitable flexible conduit 66 is interconnected into cylinder adjacent the upper end thereof, so as to deliver fluid under pressure into annular space 64. A passageway 68 (seeFIG. 5) is formed through piston to interconnect space 64 with the cylinder ahead of the piston. Thus fluid delivered will cause the piston to rise, since the effective area of the bottom of the piston is much larger than the effective area of the top of the piston. Conduit 66 is connected to a hydraulic pump or air compressor through suitable control valves, thisnot being shown as it is common and well understood in the art. l

The compressor or pump, if desired, could also be mounted on cart 12. 7

Piston rod '52 extends above cylinder 50, and a cylindrical'plug 70 is inserted slidably and removably in the upper end thereof, said plug being provided at its upper end with a circular flange 72 rigidly attached thereto, said flange resting on the upper edge of the piston rod wall. A pair of upwardly extending ears 74 are welded to the upper surface of said flange, and are connected by a pivot pin 76 to a pair of ears 78 aflixecl to and depending from a carrier designated generally by the numeral 80. Pivot pin 76 is horizontal and disposed at right angles to the axis of ram .48. Carrier 80 comprises a tubular boom slide 82 disposed above and at right angles to pivot pin 76, a pair of aligned horizontal tubular arms 84 affixed respectively to opposite sides of slide 82 and extending outwardly therefrom, an upwardly extending post'86 afiixed to the outer end of each of said arms, and ears 78, the latter being welded to arms 84' adjacent slide 82 and extending downwardly therefrom. An ordinary ladder 88, consisting of a pair of side rails 99 with rungs 92 extending therebetween and afiixed thereto in parallel, spaced apart relation, is pivotally mounted at one end between the upwardly extended portions of posts 86, by an enlongated bolt 94 which passes through holes 96 (see FIG. 5) provided therefor in post 35, and through holes 98 provided therefor in ladderside rails 50.

Telescoped slidably in boom slide 82 is an elongated tubular boom 100 which is substantially longer than said slide and which is adjustably fixable in said slide by a pair of set screws 102 threaded in said slide. On one extended end portion of said boom is mounted a ladder support 104. As best shown in FIGS. 2 and 3, said ladder support comprises a short tube 106 telescoped slidably on the boom and adjustably afiixed thereon by a set screw 108, a pair of aligned arms 110 affixed respectively to opposite sides of tube 105 and extending outwardly therefrom, and an upright post 112 affixed to the outer end of each of said arms. Said support is adapted to receive ladder 88 between posts 112 thereof as best shown in FIG. 2, with side rails 90 being supported by arms 110. The latter may be prevented from swinging away from the support, by pivotal movement on bolt 94, by a pair of retainer bars 114, each. of said bars being atfixed to the top of one of the posts 112 by a screw 116, and extending horizontally from said post to overhang the adjacent side rail 90 of the ladder. By loosening screws 116, the bars may be pivoted to a position not overhanging the latter, as in FIG. 9, so that the ladder may pivot away from the support. Also, an eye member 118 is welded to the bottom side of ladder support tube 105, for a purpose which will presently appear.

Adjacent the end of boom 100 opposite from the ladder support 104, a platform 120 is welded to the upper side thereof. Mounted on said platform is anelectric motor 122 which drives a cable drum 124 through a geared speed reducer 126. ,A cable 128 wound on said drum is extended therefrom, trained over a sheave wheel 130 mounted rotatably at the adjacent end of the boom, and depends therefrom, having a hook 132 affixed to the free end thereof. Also, an eye member 134 is welded to the lower side of boom 100 just beneath platform 120, for a purpose which will presently be described.

Mounted on cylinder 50 just above the vertical wall 14 of cart 12 is a clamp ring 136 secured rigidly thereon by a clamp bolt 133 (see FIG. 6). Apair of short, horizontally extending posts 140 are welded respectively to the opposite sides of said clampring, and extend outwardly therefrom, said posts being coaxial and parallel to the pivotal axis of carrier 80. A pair of rigid parallel links 142 are pivotally connected respectively to the outer ends of posts 140 by shouldered pivot screw 144, and extend angularly upwardly therefrom, being adapted to be releasably and pivotally secured to the outer ends of a pair of coaxial posts 146 affixed to the opposite sides of boom slide 82;, by a pair of shouldered screws 148. Posts 146 are disposed adjacent the end of slide 82 nearest hoist motor 122. Similarly, a pair of rigid parallel links 150 are also pivoted at one end on screws 144, and extend angularly upwardly therefrom, being adapted to be reieasably secured by pivot screws 152 to the outer ends of a pair of coaxial posts 154 affixed to and extending outwardly from slide 82 at the end thereof closest to ladder support 104. Links 142 may be termed .the ladder links and links 150' may be termed the hoist links.

In the use of the device as'an elevating ladder, as illustrated in FIG. 1, hoist links 150 are disconnected from posts 154 by removing screws 152. Thus when fluid under pressure is fed to ram 48 through conduit 66 to elevate piston rod 52, ladder links 142 function to elevate the end of boom 100 carrying ladder support 104, and hence to elevate ladder 88 itself, as shown in dotted lines in FIG. 1. During use of the ladder, boom 100 is extended as far as possible'to the right in slide 82, after first loosening set screws 102. This position of the boom, shown in FIG. 1, moves ladder support 104 to engage ladder 88 as far as possible from the mounting bolt 94 of the ladder, in order to support the ladder more efiiciently and to provide additional strength therefor, and also retracts the hoist end of the boom as close as possible to the ram 43, so that the hoist mechanism will still be wellelevated above the truck floor even when the ladder is raised to its maximum angle .of elevation. Lock bars 114 of ladder support 104 are at this time clamped in their operative position as shown in FIG. 2 to prevent any-possibility that the ladder could swing away from support 194, said lock bars thus constituting a safety device. Ram 48 may be rotated through 360 degrees about its axis, thereby positioning the ladder to extend in any desired direction from truck 2, by turning crank 42 as previously described, after first loosening set screws 58, and fixed at any desired position by again tightening said set screws. In place of ladder 88, any desired elongated load arm could be utilized, such as a boom, mast, or arm supporting a passenger-carrying basket or the like. In such instances, such elongated load arm would serve primarily merely as an extension of boom 100. It is considered also that an extension ladder, consisting of a plurality of telescopingly engaged sections, could be used in place of simple ladder 88 within the scope of the present invention.

When the device is to be used as a crane hoist, as illustrated in FIG. 9, ladder links 142 are disconnected by removing screws 148, hoist links 150 are connected by inserting screws 152 set screws 102 are loosened and boom 100 is moved inslide 82 to extend the hoist end thereof, which carries hoist motor 122, as far as possible from ram standard 48, and set secrews 102 again tightened. Thus when fluid under pressure is fed to the ram as before, links 150 reverse the boom action so that the hoist end thereof is elevated as shown in dotted lines. The crane hoist may of course be used for any purpose desired, but in the application illustrated is particularlyadapted for loading and unloading heavy articles into and out of the truck bed 6, the boom being of suflicient length that articlessuspended from hook 132 may be deposited in any portion of the truck bed by rotating ram 48 by means of a crank 42. In this connection, it will be noted in FIG. 5 that cart 12 is disposed adjacent one of the side walls of the truck bed, so as to form the least possible obstruction on the floor of the truck bed.

The extension of boom 100 in slide 82 toward the hoist end of the boom, as shown in FIG. 9, provides that the effective length of the crane boom, measured from pivot 76 to sheave Wheel 130, will be as great as possible to provide the highest lift, and also that the retracted end of the boom, which carries ladder support 104, will be sufficiently short that it cannot engage cart 12 to interfere with the rotation of ram 48 about its vertical axis. In this connection it may be stated generally that whether the device is being :used as an elevating ladder or as a crane hoist, and for all degrees of elevation of the boom, the retracted end of the boom may extend below pivot 76 only to an extent less than spacing of pivot 76 above the top of cart 12. Also links 142 and 150 must be attached to the ram cylinder above cart 12, in order that rotation of the ram will not cause interference between said links and any part of the cart. Referring to FIG. 5, it will be seen that clamp ring 136 is provided with a shelf-like projection 156 beneath each of pivot screws 144, said projections serving to prevent links 142 and 156 from pivoting below horizontal when they are disconnected from boom slide 82, in order that they will not interfere with axial rotation of the ram.

Ram 48 is preferably of such height that when boom 100 is disposed horizontally, ladder 88 may rest on or immediately above truck cab 4, as shown in FIGS. 1 and 9, for convenience in transporting the device from place to place. The boom may be securely locked in this horizontal transport position by connecting both the links 142 and also the links 150 to boom slide 82, as shown in FIG. 6. When the device is in use as a crane hoist, as in FIG. 9, ladder lock bars 114 are pivoted to their inoperative positions. Thus the ladder may rest on top of cab 4 and pivot freely on bolt 94 as the boom is elevated, as shown in dotted lines in FIG. 9. If the ladder still hampers use of the hoist, as could occur particularly when it is desired to rotate ram 43 about its vertical axis, the ladder may be easily detached simply by removing bolt 94.

Means are also provided for increasing the lifting force on the boom beyond that which is normally obtainable by means of links 142 or 159 with a given available fluid pressure for actuating the ram. In FIG. 1, showing use of the device as an elevating ladder, a cable 158 or other connecting device may be interconnected between eye 134 at the hoist end of the boom and eye 44 of socket 28 which carries ram cylinder 50, and both links 142 and 159 disconnected from boom slide 82. Extension of the ram will thereupon provide a greater lifting force on ladder 88 than would have been possible by use of links 142, since the lever arm represented by the distance from eye 134 to pivot 76 is greater than the lever arm represented by the distance from pivots 148 of links 142 to pivot 76. The ladder may then of course not be elevated to as great a degree of elevation as previously, but it is often quite acceptable to sacrifice some elevation or height in return for greater lifting power. Cable 158 would be used primarily when some load arm other than ladder 88, such as a boom, was being utilized, since the ram, fluid pressure, and links 142 would of course be selected and proportioned so that any load normally supported by a ladder could be elevated by use of links 142. Still greater lifting power could be obtained by extending boom 109 to the left in slide 82 (as viewed in FIG. 1), thereby increasing the distance of eye 134 from pivot '76, and increasing the length of cable 158 accordingly. Similarly, when the device is in use as a crane hoist as in FIG. 9, a cable corresponding to cable 158, or cable 158 itself, could be interconnected between eye 118 of ladder support 104 and eye 46 of ram socket 28 it being understood here also that links 150 must then be disconnected.

It will be apparent that in many cases farmers, tree .6 workers, sign hangers and others having use for the device as described may also have uses for ram 48 independent of the hoist and ladder elements. For such auxiliary uses, the ladder and hoist assembly may be quickly and easily detached from the ram assembly by lifting plug out of the upper end of the piston rod, after first of course disconnecting links 142 and 150. Cart 12 may then be detached from the truck by removing bolts 24. The cart may then be tilted slightly to rest on wheels 22, and rolled to any desired location. If the cart 12 itself would interfere with any such auxilary usage of the ram, the ram may be easily detached from the cart by first loosening set screws 54 and 58, and lifting the ram free of socket 28 and retainer rings 56 of the cart. Since the fluid connection 66 to the ram cylinder is disposed above the topmost retainer ring 56, it does not interfere with this disassembly.

While I have shown and described a specific embodiment of my invention, it will be readily apparent that many minor changes of structure and operation could be made without departing from the spirit of the invention as defined by the scope of the appened claims.

What I claim as new and desire to protect by Letters Patent is:

1. A combination elevating load arm and crane hoist comprising:

(a) a vertical standard having a lowersection and an upper section vertically movable with respect to said lower section,

(b) power means for elevating said upper standard section with respect to said lower section,

(c) means for rigidly supporting said lower standard section,

(d) a boom carrier pivoted to the upper end of said upper standard section on a horizontal axis,

(e) an elongated boom mounted in said carrier transversely to the pivotal axis thereof and being longitudinally adjustable therein whereby either end thereof may be extended to a greater distance from said standard than the other end thereof,

(f) links, each pivoted at one end to said lower standard section,

(g) means for pivoting the opposite ends of said'links to said boom carrier selectively at either of a pair of points spaced apart oppositely from the pivotal axis of said carrier in a direction parallel to said boom, whereby elevation of said upper standard section will cause elevation of one or the other end of said boom, depending on the point of connection of said links to said carrier,

(h) a hoist device mounted at one end of said boom,

(i) a load arm support mounted at the opposite end of said boom, and

(j) an elongated load a-rm attached at one end to said boom carrier and supported by said load arm support at a point spaced apart from said boom carrier, said load arm extending from said boom carrier a distance greater than the maximum spacing of said load ar-m support from said boom carrier.

2. The combination as recited in claim 1 with the addition of:

(a) a cable secured at one end relative to said lower standard section and adapted to be secured at its opposite end selectively to either end of said boom, at points thereof spaced farther from the pivotal axis of said boom carrier than the points of connection of said links to said carrier, said cable being adapted to be used in lieu of said links to increase the lifting force applied to said boom by elevation of said upper standard section.

3. The combination as recited in claim 1 wherein said standard is mounted in its said supporting means for rotation about a vertical axis.

4. The combination as recited in claim 1 wherein said standard is mounted in its said supporting means for 7. rotation about a'vertical axis, and with the addition of:

(a) means for fixing said. standard against rotation at any desired angular position.

5. The combination as recited in claim 1 wherein said means for supporting said standard comprises:

(a) a base,

(b) an upwardly opening socket carried by said base for rotation on a vertical axis, the lower end of said lower standard section being removably engaged in said socket,

(c) means carried by said base for rotating said socket,

((1) means releaseab-ly fixing said lower standard section in said socket and preventing relative rotation thereof,

(e) a retainer ring rigidly supported by said base above said socket and engaging said lower standard section to permit axial rotation thereof, and

(f) releasable means securing said lower standard section-against rotation :in said retainer ring.

6. The combination as recited in claim 1 wherein said means for rigidily supporting said standard comprises a wheeled cart, and with the addition of:

(a) releasable means for affixing said cart rigidly to a planar supporting surface. 7. The combination as recited in claim 6 wherein said boom carrier is readily detachable from said upper standard section.

8. The combination as recitedin'claim 1 wherein said means for rigidly supporting said standard comprises:

(a) a base on which said standard is mounted,.said base being adapted when said standard is vertical to rest solidly on a planar horizontal supporting surface. (b) releaseable means for afiixing'said base to said supporting surface, and (c) a pair of coaxial wheels carried rotatably by said base on a horizontal axis spaced apart horizontally from the portion of said base engaging said supporta ing surface, said wheels being spaced slightly above said supporting surface when said standard is vertical, but being adapted to be brought into engagement with said supporting surface by tilting said standard and base, whereupon said base constitutes a wheeled cart. i

' 9. The combination as recited in claim lwherein said standard constitutes a fluid-actuated ram including a cylinder, a piston operable in said'cylinder, and a piston rod afiixed to said piston and extending upwardly from said cylinder, said cylinder constituting said lower standard section and said piston rod constituting the: upper standard section, and wherein said power means for elevating said upper standard section comprises means for supplying fluid under pressure to said cylinder beneath said piston.

The combination as recited in claim 1 wherein said links functionrespectively to elevate the extended end of the boom and to lower the retracted end of the boom whenevensaid upper standard section is elevated, the vertical extent of the retracted end of the boom below the pivotal axis of the boom carrier being less, at any angle of inclination of the boom, than the elevation of said boom carrier axis above said supporting means of said standard, and wherein said links are also disposed entirely above said standard supporting means, as a result of which said standard supporting means cannot interfere with the rotation of said standard and boom about the axis of said standard.

11. The combination as recited inclaim 1 wherein said hoist device comprises:

(a) a sheave wheel rotatably mounted at one end of said boom on a horizontal axis,

(b) a platform fixed to said boom adjacent said sheave wheel,

(c) a motor mounted on said platform,

(d) a cable drum driven by said motor, and

(e) a cable wound on said drum and trained over said sheave wheel.

12. The combination as recited in claim 1 wherein said load arm constitutes a ladder detachably connected to said boom carrier.

13. The combination as recited in claim 1 wherein said load arm support is movable adjustably along said boom.

14. The combination as recited in claim 1 wherein said load arm constitutes a ladder pivoted to said boom carrier on an axis parallel to the pivotal axis of the boom carrier on the standard, and normally resting by gravity on said load arm support, so as to be parallel with said boom, and with the addition of:

(a) a releasable lock member carried by said load arm support and operable when engaged to secure said ladder against said support.

References Cited by the Examiner UNITED STATES PATENTS 768,700 8/04 Seagrave l8265 2,557,466 6/51 Richards et al. 254139.1 2,786,581 3/57 Balogh 212-8 3,149,694 9/64 Smithee 1822 SAMUEL F. COLEMAN, Primary Examiner.

Claims (1)

1. A COMBINATION ELEVATING LOAD ARM AND CRANE HOIST COMPRISING: (A) A VERTICAL STANDARD HAVING A LOWER SECTION AND AN UPPER SECTION VERTICALLY MOVABLE WITH RESPECT TO SAID LOWER SECTION, (B) POWER MEANS FOR ELEVATING SAID UPPER STANDARD SECTION WITH RESPECT TO SAID LOWER SECTION, (C) MEANS FOR RIGIDLY SUPPORTING SAID LOWER STANDARD SECTION, (D) A BOOM CARRIER PIVOTED TO THE UPPER END OF SAID UPPER STANDARD SECTION ON A HORIZONTAL AXIS, (E) AN ELONGATED BOOM MOUNTED IN SAID CARRIER TRANSVERSELY TO THE PIVOTAL AXIS THEREOF AND BEING LONGITUDINALLY ADJUSTABLE THEREIN WHEREBY EITHER END THEREOF MAY BE EXTENDED TO A GREATER DISTANCE FROM SAID STANDARD THAN THE OTHER END THEREOF, (F) LINKS, EACH PIVOTED AT ONE END TO SAID LOWER STANDARD SECTION, (G) MEANS FOR PIVOTING THE OPPOSITE ENDS OF SAID LINKS TO SAID BOOM CARRIER SELECTIVELY AT EITHER OF A PAIR OF POINTS SPACED APART OPPOSITELY FROM THE PIVOTAL AXIS OF SAID CARRIER IN A DIRECTION PARALLEL TO SAID BOOM, WHEREBY ELEVATION OF SAID UPPER STANDARD SECTION WILL CAUSE ELEVATION OF ONE OR THE OTHER END OF SAID BOOM, DEPENDING ON TH EPOINT OF CONNECTION OF SAID LINKS TO SAID CARRIER, (HE A HOIST DEVICE MOUNTED AT ONE END OF SAID BOOM, (I) A LOAD ARM SUPPORT MOUNTED AT THE OPPOSITE END OF SAID BOOM, AND (J) AN ELONGATED LOAD ARM ATTACHED AT ONE END TO SAID BOOM CARRIER AND SUPPORTED BY SAID LOAD ARM SUPPORT AT A POINT SPACED APART FROM SAID BOOM CARRIER, SAID LOAD ARM EXTENDING FROM SAID BOOM CARRIER A DISTANCE GREATER THAN THE MAXIMUM SPACING OF SAID LOAD ARM SUPPORT FROM SAID BOOM CARRIER.

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