US2101839A

US2101839A - Power hoist

Info

Publication number: US2101839A
Application number: US48328A
Authority: US
Inventors: Beatty M Crawford
Original assignee: Individual
Current assignee: Individual
Priority date: 1935-11-05
Filing date: 1935-11-05
Publication date: 1937-12-14
Anticipated expiration: 1954-12-14

Description

Dec. 14, 1937. B. M. CRAWFORD POWER HOI ST Filed Nov. 5, 1935 3 Sheets-Sheet 1 [22 vemor .5. M 6']? wfom Dec. 14, 1937. M. CRAWFORD POWER HOIST 3 Sheets-Sheet 2 Filed Nov. 5, 1955 flzremor .5. M. Crawford y N ll/11 Dec. 14, 1937. B. M. CRAWFORD POWER HOIST Filed Nov. 5, 1935 3 Sheets-Sheet 3 'IIIIIIIIIIIIIIIII/III IIIIIIIIIIIIIIIIIIIII/IIIIIIWImM/a fzzVezzzor I 31 M Crawford %wmmw Patented Dec. 14, 1937 UNITED STATS PATENT OFFICE 24 Claims.

My invention comprises a type of hoist particularly adapted for installation on a truck for loading and unloading the truck in regard to heavy articles which must be placed at different positions on the truck.

An object and feature of my invention is a hoist in which a single cable is used to form a double drop, that a. double cable line for lowering and raising articles to a boom or the like, and in transferring the load from the cable to the boom.

A further object and feature of my invention is utilizing the same cable which is wound on and off a cable drum to effect the raising and lowering of a post or column on which the boom is mounted.

Therefore, a combined object and feature of my invention is using a single cable, a vertically movable column or post with the boom thereon by which the cable may be utilized to elevate the column and thus raise the boom and obtain a 20 transference of the load from the boom to the cable, or vice versa, for lowering or lifting the load.

My invention considered in more detail as to the features of the transfer of the load from the boom to the cable for raising and lowering, consists of a boom with a track thereon on which may ride a carriage having. a hook for suspension ofthe load, the load being freely movable along the track by manual operation. A single cable leads along the 30 boom towards its outer end and may have the cable end either firmly attached or slidably mounted on a track attached to the outer end of the boom, the cable being guided by suitable pulleys. Therefore, when the load is to be lowered :17; from the boom it is rolled off of the end of the boom to the cable, the cable then forms a double loop, the bight of the cable passing over the roller or wheel of the carriage and thus lowering the load or article from the end of the boom to the =54) ground.

Another detailed feature is the reverse operation in which the load attached to the hook is raised by winding in the cable having the double drop or bight therein until the wheel of the carriage to which the hook is attached engages the outer end of the boom, the tension on the cable due to the winding drum then transfers the load from the cable to the track on the boom. As the boom may be rotated in a circle, the load may be deposited at desired places on thetruck.

Another object and feature of my invention is in the detail of the mechanism for raising and lowering the post or column. This consists of having an elongated collar in which there is a vertically slidable sleeve, andL inside of the sleeve I provide a tubular post. The single cable passing along the boom extends downwardly through the post and the sleeve and traverses a series of sheaves, certain of these being located on the lower end of the sleeve, and others fixed to the truck or to the col- 5 lar with a final lead to the winding drum. In this construction there are sufiicient runs of the cable between the fixed and the movable sheaves or pulleys to adequately handle the weight to be lifted. Therefore, when the cable is wound in, there is a 10 suiiicient pull to elevate the sleeve and hence the post. The reverse action allows for lowering the post and hence the boom.

Another detailed feature of my invention is the conjoint construction and action of the cable for 5 lifting the load and for raising and lowering the column and the boom. For instance, presuming the cable is slack andhas the double drop at the end of the boom for lifting the load, with the cable slack the post will be in its lowered position. The initial action on winding in of the cable is to lift the load from the ground to the end of the boom and transfer the load from the cable to the boom. The next action on continuing the tension on the cable by winding in the cable, is to raise the post and the boom, the load may then be swung to a position for dropping on the truck and the post may then be lowered by slackening the cable.

My invention is illustrated in connection with the accompanying drawings, in which;

Fig. 1 is an elevation of the main parts of the hoist and the driving mechanism of the winding drum, portions of the truck being illustrated in section;

Fig. 2 is a vertical section through the main portion of the hoist illustrating the telescope post, the boom, and the runs of the cable;

Fig. 3 is a horizontal section on the line 3-3 of Fig. 2 in the direction of the arrows;

Fig. 4 is a horizontal section on the line 4-4 of Fig. 2 in the direction of the arrows;

Fig. 5 is a horizontal section on the line 55 of Fig. 2 in the direction of the arrows;

Fig. 6 is an enlarged section of the end of the boom showing a position of the load carriage and the cable in either transferring the carriage from the cable to the boom, or vice versa;

Fig. '7 is a vertical transverse section on the line 'l'l of Fig. 6 in the direction of the arrows;

Fig. 8 is a plan taken in the direction of the arrow 8 of Fig. 6;

Fig. 9 is a section similar to Fig. 6 of a modified construction showing a fixed connection of the cable end.

Fig. 10 is a modification in which the fixed end of the cable is secured to the boom.

In my invention, as the hoist is particularly adapted for use on a truck; a portion of a truck frame is indicated by the numeral H, that may be considered as having a longitudinal beam I2 and a transverse beam I3 or any other suitable frame, on which is located the floor H! of the truck. A portion of the engine is indicated at I5, having the usual transmission housing I6, a covered drive mechanism I1 operating through a power shaft I8 and a friction gear assembly I9 to actuate cable drum 20. The details of the driving mechanism are given hereinunder.

' The main features of the hoist comprise a fixed collar 25 (note Fig. 2) which may besecured in any suitable manner to the frame of the truck. This is illustrated as having guide bearings 26 and 21 at the top and bottom with an internal space 28 for a lubricant. Slidably mounted in the collar there is a cylindrical sleeve 29. This has a head 30 at the top with a stop shoulder 3| to engage the upper end of the collar 25 and travel limit studs 32 secured at the bottom to limit the upper travel. Located inside of the sleeve there is an anti-friction bearing 33, held in place by the screws 34. This bearing may be slid upwardly in place in the sleeve for assembly and the studs 34 inserted. Rotatably mounted on the bearing there is a telescopic post designated by the assembly numeral 35. This has a pipe section 36 having a rotational fit in a bearing 31 at the head30 of the sleeve 29. A tubular plug 38, which may be secured at the lower end and on the inside of the pipe section 36, rests on the anti-friction bearing, that is, 'on the inner race of the bearing, so that the post section may be readily rotated on its axis.

The post 35 has an inner column section 40. This has an upset lower end 4|, forming abearing on the inside of the pipe structure 36, and also has a bearing at the head 42 of this pipe section. The head of the pipe section is provided with transverse notches 43 to engage an adjusting pin 44 (note Fig. 3) which may be inserted. through any one of the perforations 45 in the column 40, thus such column may be telescopically adjusted in the manner hereinunder described in the post section 35.

A boom or beam 50 is preferably constructed of an angle having a vertical web 5| and a horizontal flange 52, the upper edge of the web 5| forming a track 53. The boom is secured to the adjustable column member 40, there being an an-. gular brace 54 between one end of the boom and the upper end of the column. The outer end of the boom has a, semi-circular track section 55, this being made by rounding the end of the web 5| and having a termination at 56 of the flange 52.

A substantial bracket 51 has a vertical web 58 (note Fig. 7) secured to the flange 52 of the boom. This is provided with an outer flange 59 having a longitudinal slot 60, the upper edge 6| of the flange 55 forming an upper or secondary track. A lip 62 extends downwardly from the outer end portion 53 of the bracket parallel to ,the web 58 and through this may be threaded a stop screw 54.

A system of cable'connections from the drum 20 comprises first the column hoisting connection designated generally by the assembly nu- .meral 10. The cable run 1| from the cable windpreferably secured to the lower end of the fixed collar 25. The lower end of the sleeve 29 is slotted, as indicated at 13, and has a first lifting pulley or sheave 14 journaled on an axle pin 15 extending transversely across the lower portion of the sleeve 29. A second axle pin 16 is parallel to the pin 15 and carries an idler pulley 11, thus providing for a downward cable lead 18 to the pulley 14, a transverse cable lead 19 between the pulley 14 and the idler 11, an upward cable lead 80 (note particularly Figs. 1 and 2) to a second fixed pulley or sheave 8|, also mounted on ears similar to the cars 13 on the fixed collar 25. The cable has a reverse turn and a downward lead 82 to a second hoist pulley or sheave 83 also journaled on the pin 16 and offset out of alignment with the sheave 14. An upward lead 84 of the cable extends through the tubular plug 38, through the tubular post 35 and column 40, operates over a reverse direction pulley 85 which is mounted on a pin 86 secured in an angular bracket 81 at the junction of the column 4|) and the boom 55, the column having a slot 88 and the flange 53 of the boom also having a slot 89 to accommodate the pulley. The cable then has a horizontal lead 90 along the top of the flange 52 of the boom and passes over a reverse direction pulley 9| journaled on a pin 92 (note Figs. 6, 7 and 8), this pin secured in the web 5| of the boom and the web 58 of the bracket 51. A second drop guide pulley 93 is preferably slightly larger in diameter than the pulley 9| and is likewise mounted on a pin 94, also preferably secured to the webs 5| and 58. This pulley 93 is concentric to the end track 55 of the boom. The cable has a lead 95 from the horizontal lead 9|) between the two pulleys and extends upwardly to a terminal carriage 96. This carriage has a plate 91 (note Figs. 6 and 7) extending downwardly through the slot 60. Through this plate there is an axle pin 98 on which there are mounted two rollers 99, these operating'on the upper track surface 6| of the horizontal flange 59 of the bracket 51. The end of the cable has a head I mounted in a socket IDI on the lower end of the plate 91.

The load carriage, designated generally by the numeral III], is preferably provided with a vertical side plate III (note particularly Figs. 1, 2, 6 and 7), a top plate I I2 and a parallel spaced side plate H3. Between these side plates there is an axle stud 4 on which is journaled a compound pulley and roller designated by the assembly numeral H5. The roller portion has a groove I I6 to operate on the upper track edge 53 of the "web of the boom and also to engage the end curved track 55 of the boom. The pulley portion 1 is grooved and located to engage the cable 95 between the position where it passes between the two pulleys 9| and 93 and the terminal at the terminal carriage 96. The set screw 64 is for the purpose of confining the terminal carriage 96 adjacent the end 8 of the slot 60 for the purpose hereinunder detailed. The load carriage has a horizontal bottom plate II 9 connected to the vertical side plate II and an upwardly extended guide flange I20, an anti-friction bearing |2| is fitted in the horizontal plate H9 and on this is swivelly mounted a lifting hook I22, this having a head I23 resting on the anti-friction bearing, the bottom plate having a perforation for passage of a portion of the hook.

In the modified construction of Fig. 9 the bracket 51 preferably has an end flange I25, to

which the end I26 of the cable section I21 is permanently connected, this being spaced the proper distance from the pulley 93 considered in a vertical direction and from the track end 55 of the boom.

Altho there are many suitable mechanisms and constructions for operating the cable drum, I illustrate a suitable construction shown in Fig. 1. This drum is mounted on a substantial frame I30 secured to the frame of the truck,and has a worm wheel drive indicated at I3I. The worm shaft I32 carries a friction wheel I33. The drive shaft I8 from the engine transmission has an outer bearing I34 in the frame I30, and on this is slidably mounted a sleeve I35 having an outer friction disk I36 and an inner friction disk I31. This sleeve and the two disks are slidably mounted on the shaft I8 which is connected by splines by means of a lever I36 pivoted at I39 to a fixed structure. The upper end at I49 is connected to an adjustable link I4I, this link being actuated by a manually operated or other type of lever I42 shown as pivoted at I 43 to a fixed structure and connected at I44 to the link I4I. Equalizing springs I45 attached respectively to the lever I42 and the fixed structure tend to centralize the lever. In this type of drive from an engine transmission it is usual to have a sliding rod or shaft I46, and this as shown is manipulated by a double lever I41 pivoted at I48 and connected at I49 to the rod I46, this being a standard manner of connecting and disconnecting the transmission of the engine to the drive shaft I 8.

The manner of operation and functioning of my invention is as follows:

First dealing with the simple form of the drop hoist, as shown in Fig. 9, and considering only the raising and lowering of the weight independent of the raising and lowering of the column, presuming it is desired to raise a load, prior to the raising the cable is slackened by allowing unwinding of the drum forming the double drop loop, as shown in full line in Fig. 9. This gives a bight of the cable between the fixed end I26 and the pulley 93. The load may be attached to the hook in any suitable manner. Then, when the cable is wound inwardly the hook with the load is raised, bringing the groove II6 of the compound pulley and roller into engagement with the end rail edge 55 at the end of the boom. It will be understood that there must be sufficient clearance between the pulley 93 and the drop portion I2! of the cable to accommodate the combination drum and pulley I I5. A continuing winding in of the cable then causes the cable to straighten into the dotted. line position of Fig. 9. This action automatically rolls the combination drum and pulley H5 from the cable on to the upper track edge 53 of the vertical flange 5| of the boom 59, thus transferring the load carriage H9 from the loop cable to the horizontal boom, and thus when the load is entirely supported by the boom, it may be moved by hand longitudinally of the boom, thus positioning the load at the desired place on the truck in which it is desired to place it, and manifestly, as the boom with the telescopic post or column may be rotated, a load can be positioned at any desired place on the truck body.

The depositing of the load, presuming it is supported on the boom, is a reverse operation. The cable, in this case, will be tensioned so that it occupies the dotted line position in Fig. 9. The load carriage is rolled by hand, or in any other manner, towards the end of the boom, bringing the pulley portion III into contact with the inclined section of the cable. As the load carriage then rolls over the end of the track portion 55 of the boom, the load is transferred completely from the boom to the cable and the cable may be slackened to lower the load, the cable having the double drop, of which one portion is indicated at I21 in Fig. 9. The cable may be slackened in any suitable manner.

Dealing with the construction illustrated in Figs. 1, 2, 6, '7 and 8, the end of the cable in this case is connected to the terminal carriage 96. This carriage, as above described, may be located at the outer end of the bracket 51 by means of the locking pin or stop screw 64. In this case the operation is the same as if the cable were fixed at I, as shown in Fig. 9. However, I find itdesirable for most work, especially if the loads are heavy, to remove the stop screw 64 to allow the terminal carriage 96 to run lengthwise on the top of the bracket 51 the full extent of the length of the slot 69. Presuming, therefore, that it is desired to lift a load from the ground, the terminal carriage 96 will be positioned adjacent the end I I8 of the slot 60 and the cable will have a double drop, one side extending downwardly from the terminal carriage 96 and the other from the pulley 93, the load thus being supported by the pulley portion II'I, winding in the cable on the cable drum then raising the load until the groove II6 engages the track end 55 on the end of the boom. As the cable is wound in to greater extent, the terminal carriage 96 moves to the left, having reference to Fig. 6, as the load carriage H0 is gradually transferred from the cable to the track edge of the boom. This action causes the terminal carriage 96 to shift to its extreme left position, as shown in Figs. 1 and 2. The straightening of the cable between pulley 9| and the terminal carriage 96 gives a slight impetus in rolling the load carriage and hence the load towards the column supporting the boom.

In the reverse operation for lowering a load in which the end of the cable is connected to the terminalcarriage 96, the load carriage III] is rolled towards the end of the boom, the cable being somewhat slack, until the combination pulley and roller II5 engages the slightly inclined part of the cable above the boom, shown in Figs. 1 and 2. Then as the load carriage rolls over the end 55 of the boom, as shown in the position in Fig. 6, theweight is gradually transferred from the boom to the cable, at the same time the terminal carriage 96 isforced from the left end of the slot 60 towards the right end, then by slackening the cable the load carriage with the hook may be lowered.

The operation of my invention, as it relates to the raising and lowering of the column or post having the sleeve 29, the post 35, and the column 49, is as follows:

Presuming it is desired to raise a load from the ground, in which case the cable will be slackened and have the double loop from the end of the boom, in which case the sleeve 29 is in its lowermost position, hence the post 35 and column 49 will also be in their lowered position, in the first action the winding in of the cable is insufficient to raise the sleeve which carries the full weight of the boom and the load so that the load is first raised on to the boom and the cable straightened to the dotted line position of Fig. 9, where the end of the cable is fixed, or to the full line position shown in Figs. 1 and 2, where the cable travels. Then when the load is transferred to the boom, the next action in winding in the cable on account of the pulleys I2 and 8| being fixed, the pulleys 14 and 83 and the lower end of the sleeve being vertically movable, the sleeve is elevated until all of the slack is taken out of the cable. This action causes the raising of the sleeve until the contact studs 32 engage the lower end of the collar 25. 1

After the boom has been swung to its desired position for depositing the load, the post 35 with its column 40 being freely rotatable on the antifriction bearings 33, the cable is slackened by allowing Lmwinding from the winding drum, again bringing the sleeve 29 to its lowermost position, shown in full line in Fig. 2, and in the dotted line position in Fig. 1. The object of having the column 40 adjustable as to height in the post 35 is to regulate the height of the boom above the floor I4 of the truck. Presuming it is desired to load bales, such as bales of cotton, for the first layer on the floor the column is lowered to its greatest extent. This is done by lowering the column and the boom by unwinding the cable from the drum, preferably without any weight or load on the boom, engaging the boom with a prop, or one of the operators holding the boom manually, until the pin M may be disconnected from one of the perforations 45 in the column 40. The pin may then be inserted in the uppermost perforation and the post 45 raised until it contacts the pin or else the boom and the column 40 lowered and this telescopes the column to its full extent in the post. Then by using a long hitch on the bale, as shown on the lefthand side of Fig. 1 in dotted lines, the bale may be manipulated and loaded either from the ground or the platform on tothe truck or from the truck to the ground or platform. The amount of raising and lowering of the sleeve 25, as shown between the full and dottedlines of Fig. 1, is sufiicientto give clearance of the load over the floor I4 formanipulating the load.

When it is desired to handle or build a second layer, on the lowermost layer on the truck, or to remove such upper layer, the column 40 may be elevated, first by raising the whole sleeve and column and putting a prop underneath the boom, or supporting this manually, then allowing the post 35 and sleeve 29 to drop, and replacing the pin 14 in a lower perforation 45. This therefore adjusts the boom at a higher elevation above the floor of the truck and in this case a short hitch from the load to the hook may be used, (note the righthand side of Fig. 1). It will thus be seen that by utilizing the feature of raising and lowering the sleeve 25 with the post 35 and also having the column 40 telescoping the post, I may stack a load to considerable height on the truck and also unload such stack of articles.

While I do not wish to be limited to the type of control of the drum 2|], the action of the friction drive shown may be considered somewhat as follows:

For purposes of convenience the shaft I8 may be allowed to be continuously driven and when it is desired to raise the load one or the other of the friction disks I36 01" I3! is brought into engagement with friction wheel I33, depending on which one is necessary to drive the worm shaft I32 in the correct direction for winding in the cable. As soon as the cable is pulled sufficiently tight, either to raise the load to the boom or to raise the column or both, the slip action may be given by releasing the driving friction disk slightly from the friction wheel I33, and in this man- -While in the above specification I have described in detail the manner of lengthening or contracting the effective length of the post and column in which the column telescopes in the poststructure and may be adjusted to different heights, it will be understood that where a load of considerable height, such as either bales of cotton or hay, is to be loaded on the truck' or unloaded therefrom, it is usually a simpler procedure to raise the column to its maximum extent and then change the length of the lifting chain connected to the load which is attached to the hook for purposes of handling the lower, the intermediate and the uppermost layers of the articles being loaded on or off the truck.

It is also desirable, when the truck is traveling light, that is, without a load, or with a compact heavy load on the floor of the truck, to telescope the column in the post andsleeve its full amount so that it will-not extend upwardly to create height. This will reduce the center of gravity of-the load on the truck and also diminish wear due to vibration, and reduce any tendency of the boom to have a swinging movement. It will be understood that in traveling with a load the boom will be lashed to the load in a firm position or to the truck when traveling light;

In order to prevent rotation of the sleeve 29 in the collar 25 I provide the sleeve with a longitudinal groove I50 of which there may be one on each side and this groove engages a stud I5I threaded through the collar 25 (note Fig. 1). This groove in the sleeve should be of such length and so positioned that it does not pass through the guide bearings 26 and 21 as it is desirable to maintain the space between the collar and the sleeve and between these bearings packed with grease. The grease may be inserted through a grease fitting I52 (note Fig. 2).

In the construction of Fig. 10 I may utilize the same general type of boom as described in connection with other figures, except in this case one end I60 of the cable I6I is secured to the boom adjacent its outer end; the cable passing upwardly and over a fixed guide block I62 adjacent the end of the boom. The bracket 51 is provided with a guide pulley I63 mounted on a pin I64. The cable thus has a lead around this pulley and a section I65 of the cable leads to the upper of the poster column structure 40. Thereverse guide pulley is positioned adjacent the top of the post and the cable may then descend through the tubular column structure and have the'turns over the moving and fixed pulleys to the winding drum; By this construction the road carriage III} may be elevated by the double drops of the cable, the pulley of the load carriage riding on the cable and then when the cable becomes taut between the guide I62 and the pulley I63, the load carriage is transferred to the track of the boom,the carriage rolling with'its wheelon the track. In the reverse operation for lowering the load carriage from the track, as soon as the pulley of the load carriage engages the taut section of the cable between the block I62 and the pulley I53; the cable is-slack- Lil ened, thus transferring the load from the track of the boo-m to the bight of the double drop cable.

In some instances it is desirable to use my construction for raising and lowering a load; to and from a fixed track, in which case theelevating mechanism or column for the boom may be omitted and the boom or track held in a fixed position. This arrangement may use the construction of Figs. 1 through 9, or a construc: tion similar to Fig. 10 in which the pulley H33 could be spaced outwardly slightly and the cable follow the path indicated by the dotted lines I66 and I61. In this case the cable may be used merely for the purpose of raising or lowering the load carriage.

In the construction of my invention as illustrated in Figs. 1 through 8, if desired the guide pulley 9| and its pin 92 may be omitted. The bracket 51 may be lengthened so that the slot 66 extends substantially the full length of the usual part of the boom. Then if the boom be given a slight slope downwardly towards its outer end, a heavy load may be lifted using the double loop as shown in Fig. l, to raise theload from the ground. When the load carriage is transferred to the track of the boom, a continued tensioning of the cable will draw the terminal carriage 96 and the load carriage towards the column or support of the boom. In this case, of course, the section of the cable 90 does not pass along the lower portion of the boom. Thus by this construction, heavy weights which would be inconvenient to move manually on the boom may be moved by power, that is, by the continued winding in of the cable. Manifestly after the cable has been wound in and the terminal carriage 96 shifted towards the inner end of the boom, when it is desired to unload a weight or lower the load carriage light, such load carriage may roll down the downwardly inclined track towards the outer end of the boom and as the cable is slackened the terminal carriage will .be carried towards and beyond the end of the boom permitting lowering of the load carriage.

Various changes may be made in the principles of my invention without departing from-the spirit thereof as defined by the appended claims.

I claim:

1. In a hoist, a boom having a track, a cable extending longitudinally of the boom adjacent the track, a guide means at the outer end of the boom for the cable to guide the cable upwardly, a supporting structure adjacent the end of the boom for the end of the cable, a load carrier having a wheel for running on the track and a pulley for engaging the cable, a releasable winding means for the cable operative whereby a load may be supported beyond the end of the boom by a double drop of the cable engaging the pulley and by winding in the cable the load is raised and automatically transferred from the cable to the track of the boom. r

2. In a hoist as claimed in claim 1, the end of the cable being adjustably mounted and having a terminal carrier slidable in a direction parallel to the track.

3. In a hoist as claimed in claim 1, the" end of the cable being secured in afixed position above and beyond the end of the boom. 4. In a hoist, a boom having a track, a loa carriage having a wheel to run on the track and a pulley, a cableextending longitudinally of the boom, a pair of guide pulleys adjacent the end of the boom, the cable passing upwardly between said pulleys, a bracket secured to the boom adjacent its end, means connecting the end of the cable to the bracket,'a releasable winding means for the cablewhereby the cable may have a double drop from the endof the boom over one of the pair of pulleys and thelportion oi the cable connected to the bracket, the pulley of the load carriage; being adapted to ride on the bight of the double drop cable, whereby on winding in or releasing the icable the load carriage maybe raised or lowered relative to the end of the boom, the end'of the cable being secured to the bracket in such a position that when the load carriage is raised to a position adjacent the end of the boom the load carriage is transferred from the cable to the boom, the wheel of the carriage engaging the track of the boom.

'5.-In a hoist as claimed in claim 4, thesaid bracket having a secondary track witha terminal carriage slidable thereon, the end of the cable being secured to the terminal carriage, the said terminal carriage being movable under tens on of the cable in transferring the load to the boom from a position above and spaced from the end of the boom to a position substantially above the end portion of the boom.

6. In a hoist as claimed in claim 4, the end of the cable-being secured to the bracket at a position above and spaced from the end of the boom, whereby when the cable is taut, there is an upwardly and outwardly inclined section of the cable between the pair of pulleys and the fixed connection; of the cable to the bracket.

'7. Ina hoist as claimed in claim 4, the end of the boom'having a convexly curved track in the same plane as the track of the boom to engage the wheel of the load carriage in transferring a load from the cable to the boom, or vice-verse... I

8. In a hoist as claimed in claim 1, a supporting structure for the boom having a fixed and a vertically slidable element, pulleys secured respectively to the fixed and vertically slidable elements, the said cable having a portion with leads overthe fixed and the movable pulleys, such portion being located between the boom and the winding means for the cable, whereby tensioning or releasing the cable may raise or lower the boom. I r

9. In a hoist as claimed in claim 4, a'supporting structure for the boom having a fixed collar anda vertically slidable tubular structure mounted therein, pulleysmounted in fixed relation to the collar, movable pulleys mounted adjacent the lower end of the tubular structure, a change of direction guide means for the cable guiding the cable from adjacent the boom through the tubular structure and the collar and over the fixed and movable pulleys, the portion of the cable passing over the fixed and movable pulleys between the portion of the cable extending along the boom and the winding means for the cable, whereby on winding in,or releasing the cable the said tubular structure'may be elevated or lowered relative to the collar.

10. In a'hoist, the combination of a structure having a track, a cable, means for. connecting one end of the'cable in a position above and displaced from the end of the track, a load carriage transferred from the cable to the track, or viceversa.

11. In a hoist, the combination of a track, a downwardly extending convex end of the track at its outer end, a cable extending longitudinally of the track, a supporting structure above and displaced from the endof the track, means connecting one end of the cable to the supporting structure, means for guiding the cable structure adjacent the end of the track, a load carriage having a wheel and a pulley displaced laterally, the cable adjacent the end of the track being in alignment with the pulley, means for tensioning and slackening the cable whereby the load carriage operating on a bight of the cable beyond the end of the track may be raised, bringing the wheel into engagement with the track, the further tensioning of the cable rolling the load carriage off the cable on to the track, or vice-verse.

12. In a hoist as claimed in claim 11, the end of the cable having means for slidably mounting on the supporting structure, a removable means for retaining the cable end spaced its maximum distance from the end of the track, the said means when removed permitting the end of the cable to move towards and above the end of the track on tensioning of the cable.

13. In a hoist, a load carriage having a transverse shaft with a wheel and a pulley rotatably mounted thereon, a substantially horizontal track, a cable, means to actuate the cable adjacent the end of the track, a supporting structure for the cable located above and beyond the end of the track whereby the load carriage may operate on the portion of the cable between the end of the track and the end connected to the supporting structure, the pulley engaging the cable and means to tension or slacken the'cable whereby on tensioning the cable the load carriage may be elevated to bring the wheel in alignment with the track and to transfer the load carriage from the cable to the track.

14. In a hoist as claimed in claim 13, the track having a downwardly curved end whereby when the load carriage moves on the track into contact with the tensioned cable the slackening of the cable permits the load carriage to roll on the wheel on the track to engage the pulley with the cable and thereby transfer the load from the track to the cable.

15. In a hoist, the combination of a structure having a track, a cable, means for connecting one end of the cable in a position above and displaced from the end of the track whereby a double drop cable may form a bight beyond the end of the track, a load carriage having means to be supported in the bight of the double drop cable or on the track and means for tensioning or slackening the cable whereby the load carriage may be automatically transferred from the cable to the track or vice versa, the track being connected to the upper end of a post, said post being rotatably mounted in a vertically slidable but non-rotatable sleeve, the said sleeve being vertically slidable in a fixed collar, thecable having a run extending alongthe track and downwardly through the post, the sleeve and the collar, 'pulleys mounted on the lower end of the sleeve and complementary pulleys mounted in fixed relation to the fixed collar, the run of the cable after extending through the sleeve operating over the said pulleys and being connected to the tensioning and slackening means whereby the sleeve with the post and track may be raised or lowered and the post may rotate on a verti'cal axis in the sleeve.

16. In a hoist, a fixed collar having first pulleys connected thereto, a slidable but non-rotatable sleeve mounted in the fixed collar and having second pulleys on the lower end of the sleeve, a'post rotatably mounted in the sleeve and having a boom with a track connected thereto, a cable leading over the pulleys connected to the collar and thesleeve with an upward run through the sleeve and the post with means for attaching the end of the cable to the boom, the boom having a load carriage mounted thereon to engage the cable adjacent its connection to the boom and means for Winding in or releasing the cable to raise or lower the sleeve with its post and boom.

17. In a hoist as claimed in claim 16, the boom having a convex curve on the outer end of'the track and a bracket extending upwardly and outwardly beyond the end of said end, a guide means for the cable between a position adjacent the convex end of the boom and the said bracket whereby when the cable is taut there is an upwardly and outwardly inclined portion between the end of the boom and the bracket, a load carriage movable on the track and having a pulley to engage the cable, the slackening of the cable being adapted to lower the load carriage in the bight of the cable.

18. In a hoist, a boom having its inner end mounted for rotation in substantially a horizontal plane, the said boom having a track with a convex outer end, a bracket extending upwardly above the boom and projecting beyond said convex end, a cable, means for passing the cable between a position adjacent the convex end of the boom and the outwardly projecting part of the bracket, means for guiding the cable adjacent the inner end of the boom whereby when the cable is taut there may be an inclined portion of the cable extending outwardly and upwardly beyond the convex end of the track, a load car riage movable on the track of the boom and having a pulley to engage the inclined portion of the cable whereby slackening of the cable permits lowering of the load carriage on a bight of the cable beyond the end of the boom.

19. In a hoist, a boom having its inner end mounted on a supporting structure, a track on the boom having a convex outer end, a bracket secured to the boom and extending upwardly and outwardly beyond said convex end, a drop guide pulley mounted on the boom adjacent the said convex end, a reverse direction pulley mounted on the boom adjacent thereto, a cable extending along the boom and passing upwardly between the said pulleys, means to connect the end of the cable to the bracket whereby when the cable is taut there may be an inclined portion of the cable between the bracket and the guide pulley, a load carriage movable on the track and having a pulley to engage the cable between the guide pulley and the bracket whereby slackening of the cable may lower the load carriage on a bight of the cable.

20. In a hoist as claimed in claim 19, the end of the cable having a fixed connection to the bracket.

21. In a hoist as claimed in claim 19, the end of the cable being secured to a terminal carriage, said terminal carriage being slidable on the bracket.

22. In a hoist, a boom having its inner end mounted on a supporting structure, a track on the boom having a convex end, a bracket extending upwardly above the boom and in part beyond the said convex end, a first guide pulley mounted on the boom adjacent the convex end, a second and reverse direction pulley mounted on the boom adjacent thereto, a cable extending along the boom and upwardly between the two pulleys, a terminal carriage slidably mounted on the bracket, means to limit the movement of the terminal carriage, the end of the cable being secured to such terminal carriage, a load carriage slidably mounted on the track and having a pulley to engage the portion of the cable between the terminal carriage and the first pulley whereby on slackening the cable the load carriage may be lowered from the end of the boom on a bight of the cable.

23. In a hoist, a boom having a track, means to support the boom with the track substantially horizontal, the track having a convex outer end, a guide block with a convex upper surface mounted on the boom adjacent the convex end, a bracket secured to the boom and extending upwardly and beyond the said convex end, a guide pulley mounted on the bracket beyond the said convex end, a cable having one end secured to the boom adjacent the inner portion of the guide block and extending over the guide block to the said pulley, a lead of the cable extending parallel to the boom, a load carriage movable on the track and having a pulley to engage the portion of the cable between the guide block and the pulley on the bracket whereby on slackening the cable the load carriage may be lowered on a bight of the cable.

24. In a hoist, the combination of a supporting structure, having a fixed collar, a vertically slidable sleeve but non-rotatablein the collar, a column telescopically adjustable relative to the sleeve and rotatable on its axis in the sleeve, pulleys mounted in fixed relation to the collar, movable pulleys mounted adjacent the lower end of the sleeve, a cable having one end attached to means fixed in relation to the column, the said cable passing over the said pulleys and a winding means for the cable whereby on winding in or releasing the cable the sleeve and the column may be raised or lowered in reference to the collar, a boom secured at the upper end of the column and having a track thereon, with a structure forming the means for attaching one end of the cable connected to the boom, a load carriage having a wheel for operating on the track and a pulley to engage the cable adjacent the end of the boom whereby the load carriage may be transferred from operating on the track to operating on the cable adjacent the end of the boom, or vice-verse.

BEATTY M. CRAWFORD.