US2321549A - Sheave mounting for hoisting booms - Google Patents

Description

June S, 1943- E. w. HOLMES 2,321,549

SHEAVE MOUNTING FOR HOISTING OOMS Filed Sept. 26,41941 3 Sheets-Sheet 1 m t Kc) 'i o Qq j l i3 A @qu *Q m O J W r/ l wd n r/zesZW/ZW.;

June 8, 1943. E. w. HOLMES 2,321,549

SHEAVE MOUNTING FORHOISTING BOOMS Filed Sept. 26, 1941 3 Sheets-Sheet 2 r 4. y ad M W f5 fi 4f f r mk l 57 3mm ,f// W `Iune 8, 1943. E, w HOLMES 2,321,549

SHEAVE MOUNTING FOR HOISTING BOOMS Filed Sept. 26, 1941 3 Sheets-Sheet 3 Patented June 8, 1943 SHEAVE MOUNTNG FOR HOISTING ROOMS ErnestWalter Holmes, Chattanooga, Tenn., as-v a signor to Ernest Holmes Company, Chattanooga, Tenn., a corporation of Tennessee Application september 26, 1941', 's'.erialNo. 412,487

7 Claims.

The present invention relates to improvements in automobile service and wrecking trucks, and more especially to those of the type shown and described in my prior U. S. patent, Reissue No. 14,720, granted September 2, 1919, in which derrick or hoisting mechanism embodying a pair of companion booms is mounted on a truck or similar automotive vehicle, and is adapted to extricate automobiles from positions in which they may be left as the result of accidents and to tow or haul automobiles to service stations or other desired destinations.

In the developments of wrecking trucks of this double boom type for heavy duty, each boomsupporting cable is passed around a sheave carried by a link attached to the outer end of the boom in order that the boom cable may sustain greater loads imposed on the boom, but it has been found in practice that when the booms are locked together to hold them against lateral swinging, and the hoisting cable of one of the booms is employed for hauling or pulling in a direction laterally of the boom, as for example,

in pulling a disabled automobile back onto a road from a side thereof while the wrecking truck occupies a position longitudinally of the road, or substantially so, a` lateral stress was imposed upon the boom due to the link connection of the boom cable sheave to the outer end of the boom, which caused the boom cable sheave to swing laterally of the boom under the load applied thereto by the hoisting cable.

rI"he primary object of the present invention is to provide a novel and improved sheave mounting for the derrick or hoisting mechanism of service or wrecking trucks oi this type whereby such objection is obviated, and an improved operation of the derrick or hoisting mechanism is attained. According to the present invention, the sheaves for the boom and hoisting cables are journaled coaxially or on the same shaft, and are swivelled to rotate on the longitudinal axis of the boom which intersects or substantially intersects the common axis of the sheaves. The sheaves for the boom and hoisting cables are, therefore, free to swivel freely and in union about the longitudinal axis of the boom under a stress applied laterally of the boom by a load on the hoisting cable while pulling at an angle to the longitudinal axis of the wrecking truck, thus- `avoiding imposing a lateral strain on the boom or any of the other parts of the apparatus under such conditions.

Another object of the present invention is to provide a novel and improved means for swivelling the sheaves the outer rend of the boom, whereby the sheave mounting may benreadily applied to 0r removedfrom the boom when the.

`sheave is rotated into one position vabout the 1ongitudinal axis of the boom, but is securely locked against displacement fromsthe end oi the boom when thesheave mounting is rotated into the position it occupies during normal operation of the derrckor hoisting apparatus,- in which latter position it is held by the lhoisting cable suspended from its respective sheave. i Y

To these and other ends, the invention consists in certain improvements and combinations 'and arrangements ofparts, all as will be hereinafter more fully described, the features of no velty being pointed out more particularly in the claims at the end votkthis speciiication.

In the accompanying drawings:

Figure 1 is a side elevation vof a derrick or hoisting mechanism for a Wrecking truck, the same embodying the present invention;-

Figure 2 is a top plan' viewfof therouter ends of the companion booms, the same being shown locked together;

Figure 3 is a side elevation, partly in vertical section, of the outer end of onevof the booms, showing Vthe improved sheave mounting applied thereto and locked against detachment;

Figure 4 is a -vievv similar to Fig.Y 3, but show- `ing the sheave' mounting rotated into position for assemblyon the boom or detachment therefrom;

Figure 5 is a detail transverse section taken on the line 5-5 in Fig. 3`;

Figure 6 is a detail vertical section' through the sheaves and sheave mounting, taken on the line @-6Y of Fig. 3;

Figure 7 is a detail sec-tion taken on the line 'l-T in Fig. 2', but on an enlarged scale; and

Figure. 8-is a detailv section taken on the line 8-- in Fig'. 2.

Similiar parts are designated by the same reference characters in the several gures.

The improvements provided by the present invention are kapplicable generally to derricks or hoisting mechanism ofthe swinging boom type, but the improvements are particularly applicable to the derricks or hoisting mechanismY of wrecking trucks of the lgeneral type shown and described in my prior patent hereinbefore Areferrecil to, which are yadapted for Vusenot only ,for-lifting automobiles or the like iremfvthe ground or roadway,` but may Abe employed advantageously in hauling automobiles back onto the roadfrom position at the side of the road where they khave been left as the results of accidents. The invention is shown in the present instance as applied to the derrck or hoisting mechanism of a wrecking truck of that type, but it is understood that the invention is not to be limited to derrck or hoisting mechanism of this particular type, but is applicable generally to derricks or hoisting mechanisms employing a boom and hoisting and boom supporting cables which pass over sheaves mounted on the outer end of the boom.

In the present instance, the derrck or hoisting mechanism to which the present invention is shown applied comprises a frame I, which is adapted to be mounted on the chassis 2 of a wrecking truck, a portion of which is indicated at 3, this frame havin-g a boom 4 at each side which is pivoted at 5 to a bearing sleeve 6 mounted on a vertical axis 1 at the respective side of the frame, so that the boom may swing vertically about the pivot 5 and may swing laterally about the pivot 'I. The boom is supported and is raised and lowered by a boom-supporting cable 8, which is attached at one end to a link 9, and is adapted to be wound at its other end upon a winch I0. The link 9 is pivoted at II to a sleeve I2 so that this link may swing vertically, and the sleeve I2 is pivoted at I3 on a respective side of the frame I so that the link 9 may swing laterally, in accordance with raising and lowering or lateral swinging movements of the boom. The hoisting cable I4 for each boom passes over a pulley or sheave I5, which is mounted on a swivel I6 on the top of the frame, one end of this hoisting cable being preferably provided with a hook I'I which may be directly engaged with the automobile or other load to be lifted or hauled, and the hoisting cable also preferably passes around a sheave I8 which carries another lifting or hauling hook I9, which may be engaged with the automobile or other load to be lifted or hauled. The other end of the hoisting cable I4 is adapted to be wound upon a drum mounted on the frame I. The winch I0 may be operated manually, as by a crank applied to the squared end 2I of its shaft, the winch being locked against unwinding by a pawl 22 engaging a ratchet wheel 23 xed to the winch, whereby the boom may be raised and lowered and held at any desired elevation at its outer or free end. The drum 20 for the hoisting cable I4 may be power driven through a power takeoff 24 driven from the engine of the wrecking truck, the operation of the drum being effected through gearing 25 and controlled by clutch mechanism 26. The construction of the derrck or hoisting mechanism shown in the present instance is like that shown and described in my prior application, Serial No. 266,217, led April 5, 1939, now Patent No. 2,264,- 569, granted December 2, 1941, and it will be understood, as is shown in that application, that a pair of swinging booms are provided, one at each side of the frame I. The sheaves on the outer end 0f each boom, over which the hoisting and boom supporting cables pass, according to the present invention, differ from the sheave arrangement shown in said prior application` Instead of mounting the sheave or the boom supporting cable on a link attached to the outer end of the boom, as shown in that application, the boom supporting and hoisting cable sheaves, according to the present invention, are mounted coaxially on the outer end of each boom. 'K

As shown in the present instance, the hoisting cable I4 passes over a sheave 30 which is mounted centrally between the arms 3I of a fork-like 75 member 32, and this sheave is journaled to ro tate freely on a shaft 33, which extends transversely through the arms 3|. Also, in the present instance in which the derrck or hoisting mechanism is adapted for heavy duty, the boom supporting cable 8, after passing from the Winch I0, passes around a pulley 35, thence around a sheave 36, thence around a sheave 31 carried by the link 9, thence around a sheave 38, and thence to its attachment to the link 9. The sheaves 3B and 38 are journaled on the shaft 33 at opposite sides of the sheave 30, and at the outer sides of the arms 3| of the sheave mounting. The sheaves 30, 36 and 38 are thus all journaled to revolve freely on the shaft 33, which provides a common axis for these sheaves. In order to prevent disengagement of the boom supporting cable 8 from the sheaves 36 and 38, guards 39 and 40 are provided, these guards being preferably assembled on the respective ends of the shaft 33 and retained thereon by pins 4I and 42 which may extend through holes passing transversely through the ends of the shaft. Also in order to prevent disengagement of the hoisting cable I4 from its sheave 30 when this cable is slack, .a pair of guards 43 and 44 are preferably provided which are welded or otherwise fixed to the respective arms 3| of the sheave mounting and overlie the sheave 30. The guards 39 and 40 for the sheaves 36 and 38 are formed with flanges 45 and 4B which surround portions of the peripheries of these sheaves in order to retain the boom supporting cables in the grooves of these sheaves when this cable is slack, portions of the flanges 45 and 46 being cut away to permit the boom supporting cable 8 to pass to and from the respective sheaves, and in order to prevent rotation of the guards 39 and 40, and thus retain the cut away portions of their flanges in positions to clear the boom supporting cable, a portion of the flange of each of these guards is extended to form a lug 41, which is provided with a notch 48 adapted to straddle a rib 49, which projects from the outer side of the respective arm 3| of the sheave mounting.

The sheave mounting is swivelled in the outer end of the boom so that it may rotate about the longitudinal axis of the boom when the hoisting cable exerts a lateral stress upon the boom, as when pulling an automobile or other load at an angle to the longitudinal center line of the wrecking truck. For this purpose, the sheave mounting is formed with a stem or spindle 50, and the boom, or at least the outer end thereof,` is of Atubular formation, so that the stem or spindle of the sheave mounting may be introduced into the outer end of the boom. The stem or spindle is preferably formed with a shoulder 5I to form a bearing in the outer end of the boom, and about which the sheave mounting may swivel, and the inner extremity of the stern 5I) is formed with a cylindrical flange 52, which is also adapted to have a bearing within the tubular outer end of the boom. A portion of the periphery of the ange 52 is cut off or interrupted as indicatedat 53,Y and a lug 54 is provided on the stem 59 at the same side thereof on which the cut-away portion 53 is located, the lug 54, however, being located at a different point axially of the stem' 50. The tubular outer end of the boom is provided with a locking means which projects into the boom and is adapted to cooperate with theflange 52, such locking means comprising preferably a pair of studs 55 which may be welded or otherwise secured in holesfdrilled into the tubular outer end of the boom. The flange 52 vand locking lstuds 55 are so related that when the Vsheave mounting is rotated into the position shown in Fig. l, the cut-away portion ofthe flange 52 will pass inwardly beyond the lock-ing studs 55, so that the sheave mounting, while rotated into such a position, may be readily assembled in theouter end of the boom or removed therefrom should such become necessary, and when the sheave mounting is rotated into the position shown in Fig. 3, which is its normal position, the uninterrupted portion of the flange 52 will assume a position at the inner side of the locking studs 55, and will thereby lock the sheave mounting against Withdrawal from the outer end of the boom, and when the sheave mounting is in such normal position, the stud 54 will bear on the upper side of the surrounding wall of the boom and in cooperation with the shoulder 5I, will provide a bearing on which the sheave mounting may swivel in the outer end of the boom and on the longitudinal axis thereof.

The sheave mounting swivels in the outer end of the boom under control of a guide 56 for the hoisting cable I4, this guide being preferably in the form of a loop, the upper ends of which are suspended from the sheave-supporting shaft 33, and the lower portion of which is provided with a pair of cable guiding members 5l, it being understood that if the load being lifted or pulled is not directly beneath the sheave S, but is at either side thereof, the tension on the hoisting cable I4, acting through the guide 56, will rotate the sheave mounting in the outer end of the boom, under the influence of the tension on the hoisting cable I 4.

When, as shown in the present instance, the derrick or hoisting mechanism comprises a pair of swinging booms, the booms are each provided with the sheave mounting, as just described, and means is provided for locking the booms together to prevent swinging movement thereof while a load is being pulled from a side of one or the other of the booms. As shown in the present instance, the outer ends of the booms are provided with arms 5l) and 6i whichextend toward one another, the arm GI being forked, as shown in Fig. 7 to receive the end of the other arm 60, and a locking bolt 62 is provided on the arm 6| and is adapted to engage, under the action of a spring 63, in holes in the inner ends of the arms 60 and 5| and thereby lock the booms together, as shown in Fig. 2. Each of the arms 60 and 6l is preferably formed with a sleeve-like portion 60a which is slidable onto the outer end of the respective boom, and may rotate thereon and thus avoid strain while a load is applied to one or the other boom. When the booms are locked together, lateral swing of either boom is prevented, and the hoisting or service cable lll of either boom may then be employed for pulling a load toward the wrecking truckV from either side thereof while the truck is standing lengthwise of the road, and the booms extend toward the rear of the truck. When the booms are locked together, and an angular pull from the rear takes place, any tendency to pull the Swivel sheave mounting 32 out of the end of the boom will be prevented by the engagement of the iiange 52 with the locking studs 55, these parts occupying the position shown,l in

as the swivel sheave mounting abuts against the outer end of the sleeve-like-portion Gila of the respective locking arm 60 or 6l, pulling of the locking arm off of the end of the respective boom is prevented.

Although the improved sheave mounting is shown and described as applied to a derrick or hoisting mechanism in vwhich two sheavesA are provided with four lines of boom-supporting cable, it will be obvious that the invention is applicable to booms employing two lines of boomsupporting cable, in which case one of the sheaves for 'the boom-supporting Vcable may be omitted.

I claim:

1. In hoisting apparatus, the combination of a boom, a sheave mounting swivelled in the outer end of the boom for rotation about its longitudinal axis,ahoisting cable andaplurality of pairs of lines of a boom supporting cable, an inner sheave for the hoisting cable and a pair of outer sheaves for the boom supporting cable, and a shaft supported by said mounting and on which said sheaves are journaled on a common axis transverse to the longitudinal axis of the boom.

2. In hoisting apparatus, the combination of a pair of booms, means for locking together the outer ends of the booms, boom supporting and hoisting cables, and sheaves for said cables, a sheave mounting swivelled in the outer end of each boom for rotation about its longitudinal axis, and a shaft supported by each of said mountings on an axis which intersects the longitudinal axis of the respective boom and on which the respective sheaves are journaled as a common axis.

3. In hoisting apparatus, the combination of a boom and boom supporting and hoisting cables, a forked sheave mounting swivelled in the outer end of the boom for rotation about its longitudinal axis, a sheave for the hoisting cable journaled in the fork of the mounting, and a pair of sheaves for the boom cable journaled on the mounting at opposite sides thereof and coaxially with the sheave for the hoisting cable and equalizing the boom supporting cables at opposite sides thereof when the mounting swivels about the longitudinal axis of the boom.

4. In hoisting apparatus, the combination of a boom and boom supporting and hoisting cables, a forked sheave mounting swivelled in the outer end of the boom for rotation about its longitudinal axis, a sheave for the hoisting cable journaled in the fork of the mounting, a pair of sheaves for the boom cable journaled on the mounting coaxially with the sheave for the hoisting cable and at opposite sides thereof, and guards mounted at the outer sides of the sheaves for the boom cable and having projections thereon cooperative with the respective sides of the boom to prevent rotation of the guards.

5. In a wrecking truck having a pair of booms mounted to swing thereon, means for locking the Figure 3 under normal operating conditions, and 75 booms together, and boom supporting and hoisting cables, a sheave mounting swivelled in the outer end of at least one of the booms for rotation about its longitudinal axis, sheaves for the boom supporting and hoisting cables, and a shaft supported by the sheave mounting on which said sheaves are journaled on a common axis which intersects the longitudinal axis of the boom, and a guide for the hoisting cable connected to the sheave mounting for swinging the latter and the sheaves thereon about the longitudinal axis of the boom under a pull applied laterally of the boom by the hoisting cable.

6. In hoisting apparatus, the combination of a boom having a tubular outer end,V boom supporting and hoisting cables, sheaves for said cables, a sheave mountingV supporting said sheaves and having a portion rotatably and removably extending into the tubular outer end` of the boom, and means for locking said mounting in the tubular outer end of the boom While said mounting is in its normal position 'and for unlocking the mounting therefrom when rotated out of said position.

7. In hoisting apparatus, the combination of a boom having a tubular outer end, boom supporting and Vhoisting cables, sheaves for said cables, a sheave mounting on which the sheaves are journaled and having astem swvelled in the tubular outer: end of the boom, and provjections on said stem and in the tubular outer end of the boom cooperative while said sheave mounting is in its normal position to lock said mounting from axial displacement but relatively movable to release the mounting for removal when the latter is rotated out of said normal position.

ERNEST WALTER. HOLMES.

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