US2082017A - Portable crane - Google Patents

Description

June 1, 1937.

G. A. M CLAIN PORTABLE CRANE Filed May 18, 1935 5 Sheets-Sheet 2 l 30 422 *ysz INVENTOR. 6R0 VER A Mc CLA/N A T'I'ORNE YS.

June 1, 1937. A, MocLAlN 2,082,017

PORTABLE CRANE Filed May 18, 1935 5 Sheets-Shut 3 f9 84 T"). E J 88 87% 82 5 INVENTOR. I

GROVER A, McCLA/N ATTORNEYS June 1, 1937.

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10/ 100 .91 .99 1 l' L xex x \m \2\ \a W W W "I' V G. A. M CLAIN PORTABLE CRAP.

Filed May 18, 1935 5 Sheets-Sheet 4 INVENTOR. GROVER AQMCCLA/N BY M ATTORNEYS G A. MCCLAIN 2,082,017

PORTABLE CRANE Filed May 18, 1935 5 Sheets-Sheet 5 INVENTOR. GROVE? A. Mc CLA/N y 1 @01 1 ATTORNEYS.

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June 1, 1937.

Patented June 1,1937

UNITED STATES PORTABLE CRANE v Grover A. McClain, San Francisco, Calif., as-

signor of one-tenth Alameda, Calif.,

to James Harry Layne,

one-tenth to Harold L.

McClain, and one-tenth to Romey McClain, both of San Francisco, Calif.

Application May 18,

6 Claims.

My invention relates to improvements in portable cranes, and it consist of the combinations, constructions and arrangements hereinafter described and claimed.

An object of my invention is to provide a crane which is designed to be placed on the standard truck, the crane being so mounted on the truck as to give space on the truck body to carry and transport articles lifted by the crane. In standard truck cranes the chassis must be reinforced to a considerable extent in order to support the additional load of the crane, and to further support the work when it is lifted by the crane. Another feature of my invention is the provision of a caster wheel mounted directly below the mast of the crane, this wheel being brought into'play when the crane is used for lifting loads, the wheel acting as a direct support between the mast and the ground or other supporting surface.

In this way the load upon the crane when lifting an object is transmitted directly to the ground through the caster Wheel rather than to the truck chassis. The result is that a lighter truck chassis can be used for supporting the crane since the only weight needed in the chassis is that which is sufficient to support the crane when carrying no work. Of course the truck will still aid the caster wheel in supporting the load carried by the crane because the crane is carried by the truck and caster wheel.

A further object of my invention is to provide a device of the type described in which a stationary. mast is carried by the truck chassis, and is positioned so as to be out of the way of any load carried by the chassis, and in which the rtary mast is mounted on the upper part of the stationary mast, the rotary mast carrying the boom of the crane. The rotary mast can also carry the power source for the crane, or this power source may be disposed at the bottom of the stationary mast, or may even be mounted adjacent to the truck engine, and operated thereby.

The device is so constructed that it may be lifted off the truck chassis, and the truck used for ordinary purposes. The stationary mast may be mounted at'any desired position on the truck chassis either directly in back of the drivers seat as shown in one of the drawings, or mounted at the rear of the truck as shown in a simplified form of the invention on another drawing.

Other objects and advantages will appear in the following specification, and the novel features of the device will be particularly pointed out in the appended claims.

My invention is illustrated in the accompanying drawings forming a part of this application, in which Figure 1 is a side elevation of the device shown operatively applied to a truck chassis;

1935, Serial No. 22,273

Figure 2 is a plan view of a portion of the device shown in Figure 1;

Figure 3 is a sectional view taken substantially along the line 3-3 of Figure 1;

Figure 4 is a transverse section through the lower portion of the rotating mast;

Figure 5 is a vertical section through the top of the rotating mast;

Figure. 6 is a section along the line 6-6 of Figure 4;

Figure 7 is a sectional view of a part of the actuating mechanism;

Figure 8 is a side elevation of the caster wheel;

Figure 9 is a vertical section substantially along the line 9-9 of Figure 8;

Figure 10 is a section along the line l0|ll of Figure 8;

Figure 11 is a section substantially along the line ll-II of Figure 8;

Figure 12 is a section along the line l2-|2 of Figure 10;

Figure 13 is a side elevation of a modified form of the invention;

Figure 14 is a top view of the rotating mast shown in Figure 13;

Figure 15 is a perspective view of a simplified form of stationary and rotary masts; and

Figure 16 is a side elevation of the form oithe device shown in Figure 15, portions being shown in elevation.

In carrying out my invention I make use of a is formed from two channel irons 1-1 that have their leg portions facing each other, and an I-beam. 8 that is disposed between the channels l-l. A plate 9 extends along the under side of the channels and I-beams, and is secured thereto and to the truck chassis. A second plate l0 extends along the tops of the channels 1 and I-beam 8, and is also secured thereto. At the place where the mast 5 joins the box beam 6 I dispose a heavier supporting plate H, and the mast 5 is secured to this plate and the plate in turn is secured to the elongated plate Hi. In this manner the mast 5 is supported by the box beam 6 and by the truck chassis 2.

The mast 5 is additionally supported by a pair of rear angle irons l2, two pairs of side angle irons l3, and a pair of front angle irons I4, see Figure 1. A web of sheet metal i5 is secured to the pair of angle irons l2, and also to the mast 5 for providing additional support. In like mannor Figure 2 shows the pairs of side angle irons 13 as being disposed on opposite sides of webs 16 that extend from theangle irons to the mast and to the box beam 6. Also the front pair of angle irons l4 are disposed on opposite sides of a web 11 that placed between the angle irons and the mast 5. In this way the mast 5 is supported in a vertical position.

The upper portion of the stationary mast 5 rotatably carries a rotating mast l8. Figures 1, '4 and 5 show the construction of this rotating mast l8. It will be noted from these figures that the mast I8 is composed of abottom casting I9, a tubular member threaded into the casting at 2 I. and a top casting 22 threaded into the top of the member 20 at 23. The means for rotatably supporting the casting 19 comprises a coneshaped portion 24, see Figure 4, which is welded or otherwise secured to the stationary mast at a point just above the angle irons I2, l3 and I4. A taper roller bearing 25 is supported by the portion 24, and in turn rotatably supports the casting 19.

The top casting 22 rotates about the top of the stationary mast 5, and a roller bearing 26 is disposed between the casting 22 and the stationary mast 5. mast 5 as shown at 28, and this ring houses the top of the roller bearing 26 and acts as a retaining member for the top casting 22. In this simple way the mast I8 is rotatably mounted on the stationary mast 5.

The rotating mast l8 carries a boom 29 which is pivoted to the casting l9 at 30, see Figure 4.

The boom may be of any length desired and carries a pulley housing 3| at its outer end and also an extension 32.

The source of power for raising and lowering the boom and for rotating the mast l8, and also for moving the cables hereinafter described may be mounted on the rotating mast I8, if desired. This form is illustrated in Figures 1, 2, and 4.

A platform 33 is carried by the casting l9 and bracing 34 extends from the platform 33 to the top casting 22. Figures 1 and 2 show the platform 33 as carrying a standard hoisting engine 35 and hoisting drums 36. The engine 35 may be of any type desired, or it may be an electric motor or other source of power. One of the drums 36 has a light load line 31 wrapped therearound, this line then being passed over a sheave 38 carried by the side of the mast l8, and then over one of the upper set of pulleys 39 in the housing 3|, and finally over a pulley 40 on the bar 32. A load hook 4|.is secured to the free end of the line or cable 31, and this cable is used for lifting light loads. This construction is standard, and therefore needs no further description.

A heavy load line 42 leads from another drum 36 and is passed between pulleys 43 disposed on the side of the rotating mast I8. The load line is then passed over another one of the upper set of pulleys 39, and then down over another pulley constituting one of a lower set of pulleys 44. The cable is then passed around a block and tackle indicated generally at 45, and then up over the other pulleys in the lower set 44 until a sufficient number of turns has been made for lifting a heavy load. The free end of the load cable 42 may then be secured to the top of the main load housing as shown at 46. A load hook 41 is raised and lowered by means of the cable 42.

The boomraising and lowering cable 48 extends from a third drum 36 and is passed around a sheave 49 on the side of the mast I8, and is then A ring 21 is recessed in the stationary passed around a sheave 50 on the casting 22. The boom cable 48 then extends around one of the pulleys of the upper set 39 and back to a pulley 5|, see Figure 2, which is disposed on the opposite side of the casting 22. The cable 48 is then led to another one of the upper set of pulleys 39 and finally is dead-ended at a bracket 52 carried by the casting 22. It will be seen from this construction that the operator standing on the platform'33 can manipulate the various drums 36 for actuating the light load line 42, the heavy load line 31 and the boom line 48. Clutches, not shown, and operated by cranks 53are used for connecting any one of the drums 36 desired to the power source.

The means for rotating the mast I8 is shown in Figures 1, 3, 4, 6 and '7. In Figure 4 I show a worm gear 54 composed of two parts and secured to the conical portion 24. A. worm 55, see Figure I 6, meshes with the worm gear 54, and in turn has a worm gear 56 operatively connected thereto. Figure 7 shows the worm gear 56 in mesh with a second Worm 51 which is splined at 58 to a hollow shaft 59. Figure 3 shows the shaft 59 splined to a sleeve 60 which carries a beveled gear 6| at its inner end. The beveled gear 6| is mounted on a tubular portion 62 of a collar 63, which in turn is loosely mounted on a driven shaft 64. The ball race permits the sleeve 60 to rotate about a supporting pin 66, which is carried-by the collar 63. In this way a bearing support for the sleeve 60 and the shaft 59 is done away with.

- The collar 63 is mounted between two bevel gears 61 and 68, and these gears have clutches 69 and 19 that are keyed to the shaft 64. The shaft 64 is rotated by a pinion 1| which is connected to the engine 35 by a gearing indicated generally at 12 in Figure 2.

A rod 13 shown in Figure 3 carries forks 14 and 15 by means of which the clutches 69 and 10 operatively connect either the bevel gear 61 or the bevel gear 68 to the shaft 64. In'this way the shaft 59 is rotated in either direction. In Figure 2 the rod 13 is shown connected to a lever 16 which may be manually swung in either direction for effecting rotation of the shaft 59 in the desired direction.

It will be seen from this construction that the operator can rotate the mast 18 in either direction desired, the mast carrying with it the boom 29 and the source of power 35. In Figure 4 I show the two parts of the worm gear 54 connected to the cone-shaped member 24 by bolts 11 or other suitable fastening means. In Figure '7 I show the particular construction of the housing which encloses the worm gear 56 and the worm 51.

The housing is indicated at 18 and is rockably mounted on the shaft 19 of the worm 55. The casting encloses the worm gear 56 with the exception of one face of the gear, and this face is closed by a cover plate which is bolted or otherwise secured to the casting 18 by cap screws 81.

The top of the casting 18 is opened and carries projections 82 which constitute bearings for the shaft 83 of the worm 51. Thrust bearings 84 are disposed between the worm 51 and the projections 82. The collars 85 bear against the outer faces of the projections 82 and are secured in place by pins 86. A removable cap 81 covers the top of the worm 51 and is secured to the projections 82 by screws 88, or other suitable fasten ing means. As already stated the shaft 83 is splined to the hollow shaft 59 and is rotated thereby.

It will be seen from this construction that the hollow shaft 59 can swing freely about the shaft 64, see Figure 3, due to the collars 63. Also the housing I8 is free to rock about the shaft 19 and this will permit any angular adjustment between the shafts I9 and 64 to be taken up by the hollow, shaft 59 and its associate mechanism.

When the crane is used for lifting a load from the side of a truck it is necessary to counterbalance the weight of the boom 29. In Figures 1 and 8 I show movable I-beams 89 disposed between the channels I and the I-beam 8. These I-beams 89 may be extended as shown in Figure 2 for counter-balancing the weight of the boom 29. Also blocks, not shown, may be disposed between the extended I-beams 89 and the ground for preventing the overturning of the truck chassis when a heavy load is being liftedby the crane.

I also provide a caster wheel which is designed primarily to support the mast through the box beam when the mast is being used for carrying a load. This caster wheel is shown generally in Figure 1, and is shown in detail in Figures 8 to 12 inclusive. Figure 8 shows the box beam 6 as carrying triangularly shaped members 90. Two of these members are disposed on each side of the box beam and they are welded to the beam and to a plate 9| that extends beneath the beam. The plate 9| is shown in Figure 10, and it will be noted that this plate has triangularly-shaped openings 92 and 93. The apexes of these openings face toward the box beam while the bases are arcuate in shape and are disposed further away from the box beam.

A movable plate 94 is disposed beneath the plate 9| and is connected thereto by bolts 95. These bolts have spacing sleeves 96 mounted thereon for spacing the movable plate 94 a predetermined distance from a bar 91. This bar is merely for the purpose of spacing the bolts 95 the proper distance from each other. Sleeve rollers 98 are mounted on the spacers 96 and bear against the edges of the triangularly-shaped openings 92 and 93. A ball race 99 is disposed between the fixed plate 9| and the movable plate 94. This ball race is in the form of a disc with a plurality of openings I therein for receiving ball bearings IOI. The diameter of the balls IOI is greater than the height of the disc 99, and therefore a free moving connection between the moving plate 94 and the fixed plate 9| is provided.

As a means for holding the ball race 99 in the proper central position I secure a rectangular frame I02, see Figure 10, to the fixed plate 9| by screws or other suitable fastening means. Springs I03 extend from the corners of the frame I02 to the disc 99 and tend to hold the disc centrally in the frame. The area of the frame I02 is large enough to permit the bolts 95 to move from one side of the triangular recesses 92 and 93 to the opposite side without the disc contacting the inner wall of the frame. As

already stated the tendency of the springs will be to center the disc 99 in the frame I02.

The moving plate 94 carries a caster wheel I04. Figure 9 shows depending triangularlyshaped plates I secured to the under surface of the plate 94. The plates I 05 are disposed in two pairs and they provide guideways I09 therebetween, see Figure 11. The wheel I04 is'rotatably mounted on a shaft I01 and the square ends I08 of the shaft are mounted in blocks I09 which ride between the guideways I 06. Figure 11 shows the blocks I09 as having recesses H0 for receiving the inner edges of the plates I05.

' Guide strips III are welded to the depending plates I05, and cooperate with the guides I09 for guiding the blocks I09. Springs II2 are disposed between the plates III and bear upon the tops of the blocks I09. Fixed blocks 3 are disposed at the tops of the plates III and the tops of the springs II2 bear. thereagainsh It will be seen from this construction that the springs II2 tend to move the sliding block I09 downwardly for causing the caster wheel I04 to engage with the ground. The springs II2 auto matically proportion the load, carried by the crane, between the vehicle I and the caster wheel I04.

When the caster wheel is used it is free to move longitudinally relative to the truck chassis a slight distance and is also free to swing through a slight arc in accordance with the movements 3 of thetruck. For example, should the truck be moving forwardly the fixed plate 9| would have a tendency to move to the right in Figure 10. The moving plate 94 would remain stationary with respect to the ground until the bolts 95 would have their rollers 98 contact respectively the apex of the triangular recess 92 and the base of the triangular recess 93. The ball race 99 would permit this movement and the springs I03 would allow the disc 99 to move through half the distance taken by the bolts 95. If now the truck should be turned to the right or to the left, the front bolt 95 would act as a pivot for the moving plate 94 and the rear bolt 95 would swing in the recess 93 depending on the movement taken by the truck. The swinging movement of the rear bolt 95 would permit the moving plate 94 to swing in the same manner, and to allow the caster wheel I 04 to turn with the front wheels 3 of the truck. In this simple manner the wheel I04 is prevented from dragging over the ground. Should the truck be moving in the reverse direction the parts would function in the same manner, except that in this instance the rear bolt 95 would be disposed at the apex of the triangular slot 93, while .the front bolt 95 would be disposed at the base of its triangular opening 92. If the operator wishes to provide a non-yielding connection between the caster wheel I04 and the truck chassis during the operation of the crane, a block, not

shown, may be disposed beneath the plate 94 and the under surface of the block can rest directly on the top of the wheel I 04, or the block can be made U-shaped and have its legs rest on the sliding blocks I09.

When the caster wheel is not in use it may be lifted from the ground by the following mechanism: A pin I I4 is carried by the rear pair of triangular pieces 90 and a pair of cables I I5 are connected to the ends of the pin 4 and these cables are passed around pulleys II6 mounted on the shaft I01. The cables are then extended upwardly and have their ends secured to a shaft I I 1.

A crank handle 8 is mounted on the shaft, and this handle may be turned for rotating the shaft I I1 and winding the cables I I5 therearound. This will lift the sliding blocks I 09 and will free the caster wheel I04 from the ground. A pawl and ratchet mechanism H9 is used for locking the shaft II'I against rotation.

In Figures 13 and 14 I show a slightly modified form of mast. In this form the power source for the boom and the load cables is not carried by the rotating mast I0, but instead is disposed at the base of the stationary mast 5. I only show two drums I20 and I2I for actuating the boom cable line I22 and aload cable line I23. The light load line 31 is not used in this form of the device.

The drums I20 and I2I may be actuated by any source of power either from the truck engine, not shown, or from a separate source. I have illustrated in Figure 13 two worms I24 that rotate the drums I20 and I2I in the manner desired by the operator. The worm I24 may be mounted on a single shaft I25, and this shaft may in turn be operatively eonnected to the truck engine through beveled gears I26 and a shaft I21.

I use the hollow mast 5 for conducting the cables I22 and I23 upwardly to the top of the rotating mast I8. Pulleys I28 and I29 are disposed at the bottom of the mast 5 and lead the cables I22 and I23 respectively into the interior of the mast 5. Figure 14 shows two pulleys I30 and I3I, rotatably mounted between angle irons I32 which, in turn. are carried by the top casting 22. The cable I22 is passed over the pulley I30 and the cable I23 is passed over the pulley I3 I. The rotation of the drums I20 and I2I is controlled by the operator for raising and lowering the boom 29, and for raising and lowering the main load hook 41, not shown, in Figures 13 and 14.

The rotating ma t I8 may be swung about the stationary mast 5 either by power or by hand, and I have shown a worm I33 meshing with the worm gear 54, and the worm is rotated by a hand crank I34 for swinging the mast I8 on the mast 5. In all other respects this form of the device is identical to the form already described, and therefore like reference numerals will be applied and further description is unnecessary.

Another modified and simplified form of crane is shown in Figures 15 and 16. In Figure 15 I illustrate a truck body at I35, and this body has a stationary mast I36 mounted at any convenient place on the truck. Figure 15 illustrates the mast I36 as being disposed at one of the rear corners of the truck body. A collar I31 is secured to the stationary mast I36 and a rotating mast I38 rides on the collar I31 and rotates about the stationary mast I36. A boom I39 is carried by the bottom of the rotating mast I38 and is held in adjusted position by means of a link I40. A sheave or pulley MI is mounted at the free end of the boom I39, and a load line I42 is passed over this sheave and then over a second sheave I43 carried by the top of the rotating mast I38. A drum I44 is mounted at the base of the stationary mast I36 and the load line I42 is wrapped therearound. A crank I45 is used for paying out or winding in the load line. The free end of the load line I52 carriesa load hook i-IB. The line I42 is passed down through the hollow mast I36 and out over a pulley M2 to the drum I44.

The operation of this form of the device is the same as that set forth in the other two forms except that the device is manually actuated. The boom I39 is free to rotate about the mast I36 and can swing loads from the ground and convey them into the truck body. A pawl and ratchet indicated generally at I41 is used for supporting the load in any desired position.

A keeper plate I06 is disposed at the bottom of each guideway I II and acts as a stop for lim ting the downward movement of the wheel I04 and axle I01. Figure 9 shows a space between the plate 9 and the plate 9| for slidably receiving the bar 91. The bases of the lriangular recesses 92 and 93 are arcuate in shape as already stated, and the radius of each arc has its center in the apex of the opposite recess.

While I have shown only the preferred forms of my invention, it should be understood that various changes or modifications may be made within the scope of the appended claims without departing from the spirit of the invention.

I claim:

The combination with a truck, of a stationary mast carried thereby, a rotatable mast mounted at the top of the stationary mast, a boom pivotally carried by the rotatable mast, and a caster wheel mounted beneath the stationary mast and designed to rest on the ground to provide a direct support for the stationary mast from the ground and to aid the truck in supporting the mast when the latter is carrying a load. 1

2. The combination with a truck having a body, of a stationary mast carried thereby, a second mast rotatable on the first, a boom carried by the rotatable mast, a caster wheel for aiding the truck in supporting the stationary mast when supporting a load, said wheel turning in the direction in which the truck is moving for supporting the mast during the movement.

3. In combination, a truck frame, a crane supporting member carried by the frame, a crane mounted on the supporting member, and a caster wheel mounted beneath the supporting member for aiding the frame in supporting the crane when the latter carries a load, said mounting for the caster wheel comprising a member movable with respect to the crane supporting member, frictionless means disposed between the members, and guide means for permitting either end of the caster wheel to swing laterally as the truck frame is moved over the ground, this depending on the direction of truck frame movement.

4. The combination with a truck provided with a drivers compartment, of a crane mounted on the truck immediately in back of the compartment and comprising a stationary mast secured to the truck, a rotatable mast disposed on the upper end of the first mast and terminating just above the drivers compartment, a boom and a power unit carried by the rotatable mast and extending diametrically away from each other, and means actuated by the power unit for rotating the rotatable mast, said boom and power unit swinging freely across the top of the compartment during the rotation of the rotatable mast.

5. The combination with a vehicle, of a crane normally supported by the vehicle, and a caster wheel for providing an auxiliary support for the crane, said caster wheel being mounted on a member, and guide means for permitting either end of the member to swing laterally when the caster wheel swings about a vertical axis, the swinging of the member depending on the direction of movement of the vehicle.

6. The combination with a vehicle, of a crane carried thereby, said vehicle being strong enough to support the crane when the latter does not carry a load, a caster wheel carried by the vehicle and designed to contact the ground for aiding the vehicle in supporting the crane when the latter carries a load, and spring means interposed between the caster wheel and the vehicle for proportioning the load of the crane between the vehicle and the caster Wheel.

GROVER A. McCLAIN.

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