US3426917A

US3426917A - Mobile crane and tow truck

Info

Publication number: US3426917A
Application number: US598823A
Authority: US
Inventors: Charles R Siegel
Original assignee: CHARLES R SIEGEL
Current assignee: CHARLES R SIEGEL
Priority date: 1966-12-02
Filing date: 1966-12-02
Publication date: 1969-02-11
Anticipated expiration: 1986-02-11

Description

Feb., ll, 1969 c. R. slr-:GEL 3,426,917

4 MOBILE CRANE AND TOWVTRUCK Filed Deo. 2, 1966 Sheet of 6 Feb. l1, 1969 c. R. slEGr-:L

MOBILE CRANE AND TOW TRUCK Filed Dec. 2. 1966 Feb. l1,A 1969 vc. R. SIEGEL MOBILE CRANE AND TOW TRUCK snee-t Filed Deo. 2. 1966 Feb. 11, 1969 c. R. SIEGEL.

MOBlLE CRANE AND TOW TRUCK Filed D60. 2, 1966 Feb. 11, 1969 c. R. SIEGEI.

MOBILE CRANE AND TOW TRUCK Sheet Filed Deo. 2. 1966 um :Nw NN Wm, mm,

6 of G Sheet c. R. sn-:GEL

MOBILE CRANE AND TOW TRUCK Feb.. 11, 1969 med nec. 2, 196e gig United States Patent O Claims ABSTRACT 0F THE DISCLOSURE A crane mounted on a truck so that it can be employed to tow disabled vehicles as Well as to lift them and other loads completely off the ground. The boom is formed of telescopic sections that are extended and retracted by a pulley and cable system. The boom sections ride on rollers relative to each other to facilitate their telescoping movement. The boom is supported for pivotal movement in a vertical plane by a rotatable column, Which is rotated about its axis by a pair of piston and cylinder mechanisms through a chain drive for positioning the Iboom. Winches are provided to extend and retract the Iboom and pivot it in a vertical plane as Well as to raise and lower the load. These Winches are mounted to rotate lwith the column. The upstanding column is supported at its bottom and at its top for the sake of rigidity.

Summary of the invention Tow trucks for towing disabled vehicles are frequently equipped With a crane for lifting one end of a disabled vehicle While it is being towed. Since such cranes are mounted on a relatively small truck that can be conveniently driven on the highways and urban streets it has been accepted that the conventional crane on a tow truck has extremely limited maneuverability. The conventional tow truck crane is just adequate to lift one end of a disabled vehicle for towing purposes and very little more Without sacrificing a substantial amount of speed and maneuverability in the vehicle on Which the crane is mounted.

It is therefore a general object of the present invention to provide an improved crane assembly.

Another object of the present invention is to provide an improved crane assembly for mounting on a vehicle to render it mobile.

Another object is to provide an improved crane assembly that is extremely maneuvera-ble and versatile but Which can be mounted on a relatively small vehicle.

Another object is to provide an improved mechanism for telescoping a crane to facilitate its extension and retraction and to increase its range.

Another object is to provide a mobile crane that is relatively light in Weight and extremely maneuverable and has an extended range Without sacrificing lifting capacity.

Another object is to provide a mobile crane that is especially Well adapted to tow and lift disabled vehicles completely off the ground.

A further object is to provide an improved mobile crane and tow truck assembly of simple and inexpensive but sturdy construction which is very ehcient in operation.

According to this invention the improved mobile crane and tow truck assembly comprises a frame that supports a rotary base or turntable having an upstanding column that rotates With the base. In order to increase its rigidity, braces extend upwardly from the frame to be coupled to the top of the column to resist the binding forces that are applied to the column during the operation of the crane.

The boom extends outwardly from the rotary base and ICC is pivotal in a vertical plane relative to the base. Accordingly, the boom Will rotate bodily in an orbit with the rotation of the base and Will also pivot vertically relative to the base.

The boom comprises a plurality of telescoping sections of lattice construction Which provides strength with minimum weight. The several sections are supported on rollers that ride on way surfaces of adjoining sections for telescopic movement relative to each other so that there is a minimum amount of resistance to their telescoping movement. A unique pulley and cable drive is provided for telescoping the boom sections to further facilitate its operation.

The column supports a pair of power operated Winches. One of the Winches operates the cable for raising and lowering the boom in its vertical pivotal movement. The other winch forms the load hoist for drawing in and paying out the cable which is provided for connecting the load to the crane. A pair of drums are likewise rotatably supported by the rotary base for receiving the ca-ble of the pulley and cable drive for telescoping the boom sections.

The power drive for rotating the base to position the boom comprises a sprocket mounted on the underside of the base With its axis coinciding With the axis of rotation of the base. A drive chain is in meshing engagement With the sprocket. An end of the chain is connected to one piston and cylinder mechanism while the other end of the chain is connected to a second piston and cylinder mechanism. Hydraulic uid is admitted and exhausted from opposite sides of the respective piston and cylinder mechanisms to move their associated pistons for actuating the chain in its path of travel to effect rotation of the base for selectively positioning the boom.

The foregoing and other objects of this invention Which Will become more fully apparent from the following detailed description of an embodiment thereof may be achieved by the apparatus herein described by Way of example in connection with the illustration of its structural components in the accompanying drawings, in which:

Description of drawing FIGURE 1 is a side elevational View of a mobile crane and tow truck incorporating the features of the present invention;

FIGURE 2 is an enlarged side elevational view of the crane that is shown mounted on the truck in FIGURE l, with the boom of the crane ybeing shown in its retracted condition;

FIGURE 3 is a side elevational View of the crane that is shown mounted on the truck in FIGURE l, with the boom of the crane being shown in its extended condition;

FIGURE 4 is a front elevational view of the column portion of the crane shown in FIGURE 3;

FIGURE 5 is a detail plan view illustrating the drive mechanism for rotating the column shown in FIGURE 4;

FIGURE 6 is a plan view of the crane assembly illustrated in FIGURE 2;

FIGURE 7 is a side elevational view of the telescoping boom portion of the crane, showing the arrangement of the rollers that support the boom sections for sliding movement relative to each other;

FIGURE 8 is a plan view of the telescoping boom portion of the crane in its retracted condition showing the pulley and cable mechanism for extending and retracting the boom;

FIGURE 9 is a view of the boom substantially in vertical section taken along the plane represented by Ithe line 9--9 in FIGURE 8;

FIGURE is a view of the boom substantially in vertical section taken along the plane represented by the line 10-10 in FIGURE 8; and

FIGURE 11 is a perspective schematic view of the boom portion of the crane illustrating the operation of the pulley and cable mechanism for exending and retracting the telescoping boom.

Description of the preferred embodiment Reference is now made more particularly `to the drawings and specifically to FIGURE 1 thereof which illustrates a mobile crane and tow truck incorporating the features of the present invention. The mobility is provided by a conventional truck generally identified by the reference numeral 20. The truck includes the usual truck frame 21 on which is mounted the base of the crane, the base being generally identified by the reference numeral 22. An upstanding column 25 is mounted on top of the base 22 and an extensible boom generally identilied by the reference numeral extends outwardly of the column 25.

The crane base 22 includes four depending piston and cylinder mechanisms 31 with one piston and cylinder mechanism 31 being located at each corner of the base 22. A piston rod 32 extends downwardly from the bottom end of each of the piston and cylinder mechanisms 31 and is provided with a foot 33 at its extending end for selective engagement with the ground. Thus, in FIG. 1, the feet 33 of the several piston and cylinder mechanisms 31 are shown retracted so that the entire unit is supported by wheels 34 of the truck 20. When it is desired to operate the crane in a work operation, a more solid footing is desired so the connecting rods 32 and their associated feet 33 are extended from the piston and cylinder mechanism 31 as illustrated by the broken lines in FIG. 1 to engage the surface upon which the truck 20 is standing. The connecting rods 32 may be extended slightly further than i1- lusrtated in FIG. 1 to actually lift the rear wheels 34 of the truck 20 from the supporting surface so that a solid fixed support is provided for the operation of the crane.

As best shown in FIGS. 4 and 6, the base 22 includes a pair of end members 35 that are separated from each other by a pair of parallel structural members 36 which are of box cross section as shown in FIG. 4. The ends of the parallel members 36 are secured to the end members 35 to form a frame and a plate 37 is mounted on top of the two structural members 36.

The plate 37 serves as a support for the column 25 in the manner best illustrated in FIG. 4. An annular bearing retainer 40 is rigidly secured to the top surface of the plate 37 for receiving a tapered roller bearing 41. A post 42 is journalled in the bearing 41 and extends through an opening in the plate 37.

The upper portion of the post 42 above the plate 37 supports a member 44 on which is mounted a plate 45 which is shaped into the configuration of a sector as clearly illustrated in FIG. 6. Depending skirts 46 are secured to the rectilinear edges of the plate and a boom foot 47 extends forwardly and upwardly of the depending skirts 46 for supporting the boom 30. The plate 45 and its supporting structure constitutes a turntable which carries the column 25 to render it rotatable.

The plate 45 is attached to the member 44 by bolts 48 as illustrated in FIG. 4. A frame of the column 25 is mounted on the plate 45 and comprises a pair of upstanding parallel plates 50 that have their bottom ends secured to the plate 45 by welding or the like. The plates 50 are connected to each other at their uppermost ends by a plate 51. A bearing 52 is mounted on top of the plate 51 for cooperation with a bearing 53 which is journalled thereon as shown in FIG. 2. The bearing 53 includes two pairs of ears 54 extending radially therefrom. Each pair of ears 54 is spaced sufficiently to receive a flattened end 55 of one of a pair of braces 56. A pin 57 extends through each pair of ears 54 and its associated flattened end 55 of the brace 56 for connecting the cooperating brace 56 to the bearing 53.

The opposite end of each of the two braces 56 is likewise provided with a flattened end 58 disposed between a pair of ears 59 that are rigidly secured to the end plate 35 as clearly illustrated in FIG. 6. A pin 60 extends through each pair of ears 59 and their associated ilattened end 58 as shown in FIGURE 2 for securing the bottom end of the two braces 56 to the end member 35 of the crane base 22. With this arrangement, the column 25 is journalled for rotation in the tapered roller bearings 41 at its lower end while the upper end is journalled in the bearing 53 `that is supported by the two braces 56 for rigidly supporting the column 25 in a vertical position. The upper support of the column 25 by the braces 56 produces a great deal of strength in the column 25 for supporting the loads lifted by the crane, and yet the structural members need not be extremely heavy for carrying the stresses that are developed.

Partial `rotation of column 25 is achieved by means of a hydraulically actuated chain drive which is best illustrated in FIGURE 5. It comprises a pair of piston and cylinder mechanisms 64 and 65 mounted underneath the plate 37 A piston rod l66 extends outwardly of the piston and cylinder mechanism '64 and is connected to a drive chain 67 which is in meshing engagement with a sprocket 70 that is secured to the bottom end of the post 42 as depicted in FIGURE 4. The opposite end of the chain 67 is connected to a piston rod 71 that extends outwardly of the piston and cylinder mechanism 65. In order to effect rotation of the sprocket 70 to thereby produce a corresponding rotation of the column 25, hydraulic uid is admitted to opposite ends of the cylinders of the piston and cylinder mechanisms 64 and 65. Thus, if it were desired to effect rotation of the sprocket 70 in a clockwise direct-ion, as viewed in FIGURE 5, hydraulic pressure would be admitted into the port 72 of the piston and cylinder mechanism 64 and exhausted through the port 73. At the same time, hydraulic pressure would be admitted into the port 74 of the piston and cylinder mechanism 65 and exhausted through the port 75. A suitable hydraulic control valve (not Shown) is provided for simultaneously regulating the tiow of hydraulic pressure into and out of the piston and cylinder mechanisms 64 and 65.

The boom 30 is formed of `four

telescoping sections

80, 81, 82 and 83 which are of lattice construction to give maximum strength for a given weight. The section is the largest section of the boom and the section 81 slides into the interior of the section 80. In similar manner, the section 81 is larger than the section 82 and the latter slides into the interior of the section 81. The smallest section of the boom 30 is the section 83 which is adapted to slide into the interior of the section 82. In this manner the four sections of the boom 30 telescope relative to each other for the purpose of extending and retracting the boom.

'Ihe boom 3e is supported by the boom foot 47 for pivotal movement relative to the column 25. To this end, a pair of

stub shafts

85 and 86 extend through suitable openings in the boom yfoot 47 as well as through suitable opening-s in a pair of

plates

89 and 90` that are rigidly attached to the bottom end of the boom section 80 as clearly shown in FIGURE 6. The stub shaft 85 is also supported Aby a plate 91 that is attached to the forward portion of the plate 45 and a pulley 92 is rotatably supported by the stub shaft 85 between the plates '89 and 91. A-s illustrated in FIGURE 4, a pair of pins 93 retain the shaft 85 in the assembly. One pin 93 is inserted diametrically into one end of the shaft 85 outside of the plate 91 and the other pin 93 is likewise inserted diametrically into the opposite end ofthe stub shaft 85 outside of the bracket 47. The stub shaft 86, in addition to being supported by the boom foot 47 is also supported by a plate 94 and a pair of pins 95 to retain the assembly on the Stub shaft 86. One of the pins 95 is inserted transversely in the stub Ishaft 86 outside of the boom foot 47 while the other pin 95 is inserted in a like manner in the opposite end of the stub shaft 86 outside of the plate 94 as clearly shown in FIGURE 4.

The boom sections are supported `for sliding movement relative to each other by a unique Isystem of rollers that ride on ways `formed on adjacent hoorn sections to facilitate the extension and retraction of the boom 30. The arrangement of the rollers is best illustrated in FIGS. 7 and 10 which depict two different vie-ws of the several boom sections. The boom section 80 is, of course, xed against longitudinal movement so that it Iis stationary during the extension and retraction of the Ihoorn 30. The section 81 is the next largest section and it moves into and out of the interior of the stationary section 80. It is supported for such sliding movement into and out of the stationary section 80 by a pair of rollers 101 that are rotatably secured to the bottom end of the sect-ion 81 by suitable brackets 102. One of the rollers 101 is illustrated in FIGURE 7 while both of them are illustrated in the cross sectional view of vFIGURE l0. The two brackets 102 are secured to the movable section 81 at its lowermost end and each of the rollers 101 is rotatably carried by one of these brackets 102. The rollers 101 are so positioned that their periphery rolls along the way surfaces formed on the interior of the stationary section 80. The periphery of the rollers 101 are actually -in contact with the way surfaces provided by the interior of a pair of angles 103 which are a part of the stationary section 80 and constitute two corners of this section as clearly shown in FIG- URE 10. The upper end of the movable section 81 is guided by a pair of rollers 106 that are respectively rotatably supported by a pair of brackets '107 that are secured to the stationary section 80 as illustrated in FIGS. 2 and 3. Only one of the rollers 106 is illustrated in FIG- URE 7 but another such roller is disposed on the other side of the section 80. The two rollers 106 are journalled in their cooperating brackets 107 and are located so that their peripheries rest upon a way surface formed on the exterior upper surface of the section 81 to guide the latter section in its longitudinal movement into and out of the stationary section 80.

Similar roller arrangements are provided for guiding and facilitating the movement of the two

sections

82 and 83. Thus, the section 82 is provided with a pair of brackets 109 disposed on either side of its bottom end with each bracket 109 rotatably supporting a roller 110. Accordingly, the rollers 110 move with the section 82 and they are located so that their peripheries engage the interior surface of the section 81. To this end, the two rollers 110 ride along `respective way 1surfaces formed along the interior surfaces of angles 111 which constitute the lower two longitudinal corners of the movable section 82.

The upper end of the movable section 82 is guided by a pair of rollers 115, one of which is illustrated in FIGURE 7, although an identical roller is disposed on the opposite side of the top end of the section 82. The two rollers 115 are rotatably supported by two respective brackets 116 that are shown in FIGS. 2, 3 and 7. The brackets 116 are fixed to the boom section 81 for movement therewith but the rollers 115 are located se that their peripheries engage way surfaces formed on the upper exterior surface of the movable boom section 82. Therefore, as the boom y82 moves into and out of its cooperating movable section 81, the lower end of the section 82 is guided by the rollers 110 which move with it in its longitudinal movement and .roll along the way surfaces formed on the interior surface of the section 81, and the upper end of the section 82 is guided by the rollers 115 which roll and engage the way surfaces formed on the section 82 but do not otherwise move with the longitudinal movement of the section 82 since their axes are mounted for Amovement with the adjacent larger section 81.

The same roller arrangement is provide for the last movable boom section 83. A pair of brackets 119 are secured for movement with the boom section 83 as clearly shown in FIGURE l0 and each of the brackets 119 rotatably supports a roller 120. The rollers 120 are located so that their peripheries ride along the interior surfaces of the adjacent boom section 82. Thus, the peripheries of the rollers 120 ride along way surfaces formed by the interior surfaces of respective angles 121 which actually form the lower longitudinal corners of the movable boom section 82. Accordingly, the lower end of the boom section 83 is supported for sliding movement by the two rollers 120 riding along the way surfaces formed within the interior of the section 82 by the angles 121. The upper end of the boom section 83 is guided by a pair of lrollers 122 that are journalled in brackets 123. Only one roller 122 and one bracket 123 are shown in FIGURE 7 but another identical roller 122 and another bracket 123 are located on the opposite side of the upper surface of the boom section 83. The brackets 123 are mounted on the adjacent boom section 82 but the rollers 122 are located so that their peripheries engage way surfaces formed along the adjacent movable boom section 83. Thus they serve to guide the boom section 83 for movement relative to the adjacent section 82 as the section 83 moves into and out of the section 82 during the retraction and extension of the boom 30.

A novel reave or pulley and cable arrangement is provided for eifecting the extension and retraction of the boom 30. The pulley and cable arrangement is of simple and relatively inexpensive construction and yet operates extremely efficiently while requiring a very minimum of maintenance. The system is best illustrated in the schematic View of FIGURE l1 and comprises a continuous cable 130, one end of which is attached to a drum 131 and the other end is attached to a drum 132 which are illustrated in FIGURE 6. The two drums 131 and 132 are rotated in unison, in the same direction, so that both ends of the cable are either being taken in and wound about the two drums 131 and 132 respectively for extending the boom 30 or they are being simultaneously paid out for retracting the boom 30. The two drums 131 and 132 are supported above the plate 45 by a pair of brackets 133, one of which is illustrated in FIGURE 2. The drum 131 is located on one side of a transmission 1-34 while the other drum 132 is coaxial with the drum 131 but is located on the opposite side of the transmission 134. The transmission 134 includes two drive shafts connected to rotate the drums 131 and 132 simultaneously. The transmission 134 is actuated by a motor 135 that has a sprocket keyed to its output shaft for actuating a drive chain 136 that is also in meshing engagement with a sprocket on the input shaft of the transmission 134. Energization of the motor 135 in either direction will therefore actuate the transmission 134 in a like direction to effect rotation of the two drums 131 and 132 for extending and retracting the boom 30.

The cable extends from the two drums 131 and 132 into the interior of the several sections of the boom 30 for operating engagement with a plurality of pulleys that are rotatably mounted within the several boom sections for cooperation with the cable. As most clearly illustrated in FIGURE lil, the cable 130 passes from the drum 131 along the underside of the rotatable pulley 92 for guiding the cable into the interior of the stationary boom section 80. In like manner, the cable 130 passes from the drum 132 to the underside of a pulley 137 which is rotatbly supported by the stub shaft 86. The pulley 137 also serves to guide the cable 130 to the interior of the boom section 80. From the pulley 92 the cable 130 passes to a pulley 140 which is rotatably supported at the upper end of the stationary boom section 80. On the other side of the boom section 80, the

cable 130 passes from the pulley 137 to a pulley 141 which is 'likewise rotatably supported by the stationary boom section 80 at its uppermost end with the axis of the pulley 141 being in substantial alignment with the axis of the pulley 140. The moutning of the

pulleys

140 and 141 on the boom section 80 is also illustrated in FIG. 9 where the pulley 140 is journalled on a shaft 142 which is carried by a side plate of the boom section 80. In like manner, the pulley 141 is journalled on a shaft 143 that is carried by the opposite side plate of the boom section 80.

The cable 130 passes underneath and over the pulley 140 and extends rearwardly therefrom to an angularly disposed pulley 148 that is rotatably supported at the bottom end of the movable boom section 81. In like manner, on the other side of the boom structure the cable 130 passes underneath the pulley 141 and over it to extend rearwardly for engagement with an angularly disposed pulley 149 that is rotatably carried at the bottom end of the section 81 opposite the side that carries the pulley 148. IIt should be especially noted that the

pulleys

140 and 141 are supported at the upper end of the section 80 while the angularly disposed

pulleys

148 and 149 are rotatably supported at the bottom end of the movable section y81. The mounting of the angularly disposed pulley,148 and 149 is clearly shown in FIGURE l0 where the pulley 148 is shown as journalled on a stub shaft 150 that is carried by a bracket 151 which is mounted on a side plate of the movable boom section 81. The pulley 149 is carried on the opposite side of the section 81, being journalled on a stub shaft 152 which is carried by a bracket 153 that is supported by a side plate of the boom section 81.

From the angularly disposed pulley 148, the cable 130 passes upwardly to a pulley 160 which is rotatably supported by the upper end of the boom section 81. In like manner, the cable 130 passes upwardly from the angularly disposed pulley 149 to a pulley 161 which is also rotatably supported at the upper end of the section 81 with its axis in alignment with the axis of the pulley 160. The pulley 160 is located on one side of the upper end of the section 81 While the pulley 161 is disposed on the opposite side. It should be noted that the angularly disposed

pulleys

148 and 149 are both supported at the bottom end of the movable section 81 while the

pulleys

160 and 161 are rotatably supported at the upper end of this same section 81. The mounting of the

pulleys

160 and 161 on the section 81 is clearly illustrated in FIG. 9. As there shown, the pulley 160 is journalled on a stub shaft 162 that is carried by a side plate of the section 81. In like manner, the pulley 161 is journalled on a stub shaft 163 that is carried on the opposite side of the boom section 81.

As best shown in FIGURE l1, the cable 130 passes under and over the pulley 160 to extend rearwardly for engagement with an angularly disposed pulley 168 that is rotatably supported by the movable boom section 82. In like manner the other portion of the cable 130 passes under and over the pulley 161 to extend rearwardly into operating engagement with an angularly disposed pulley 169 which is also rotatably supported at the bottom end of the boom section 82. It should be again noted that the

parallel pulleys

160 and 161 are supported -by the boom section 81 while the two angularly disposed

pulleys

168 and 169 are supported by the succeeding boom section 82. As a result, the spacing of the pair of

pulleys

160 and 161 from the pair of

pulleys

168 and 169 may vary.

The mounting of the angularly disposed

pulleys

168 and 169 is best Shown in FIGURE l0. The pulleys 168 is journalled on a stub shaft 170 that is carried by a bracket 171 which is supported by a side plate of the -movable boom section 82. The opposite side plate of the boom section 82 supports a bracket 172 which carries a stub shaft 173 upon which the pulley 169 is journalled.

The cable 130 extends from the angularly disposed pulley 168 to a pulley 180 which is rotatably supported at the upper end of the same section 82. In the same manner, the cable extends upwardly from the angularly disposed pulley 169 to a pulley 181 which is also rotatably supported at the upper end of the section 82 on the side opposite the side that supports the pulley 180. The axes of the two

pulleys

180 and 181 are in alignment so that the pulleys are parallel to each other. It should be again noted that the angularly disposed

pulleys

168 and 169 are located at the bottom end of the section 82 while the two

parallel pulleys

180 and 181 are located at the upper end of the same section 82. The mounting of the

pulleys

180 and 181 on the boom section 82 is clearly shown in FIGURE 9. The pulley 180 is journalled on a stub shaft 182 that is carried by a side plate of the boom section 82. Similarly, the pulley 181 is journalled on a stub shaft 183 which is carried on the side of the section 82 that is opposite the side that carries the stub shaft 182.

The continuous cable 130 passes underneath and over the two

pulleys

180 and 181 into engagement with a pulley 185 that is rotatably supported at the bottom end but on the top surface of the inal movable boom section 83. As illustrated in FIGURE 10, the pulley 185 is journalled on a stub shaft 186 which is carried by the top plate of the movable boom section 83. It should be again noted that the two

parallel pulleys

180 and 181 are rotatably supported by the upper end of the boom section 82 while the pulley 185 is rotatably supported at the bottom end of the adjacent boom section 83. As a result, the spacing of the

pulleys

180 and 181 from the pulley 185 may vary. The pulley 185 is provided for greater flexibility and eliiciency in the operation of the pulley and cable system although the system would also function if the cable were anchored at the bottom of the movable boom section 83 instead of being wound around the pulley 185.

The operation of the pulley `and cable system for extending and retracting the boom 30 may be best understood from the schematic view in FIGURE 1l. The boom 30 is illustrated in that ligure in its extended condition with the several -

movable boom sections

81, 82 and 83 extending a maximum amount outwardly of the sect1on from-which they telescope. As a result, each pair of angular pulleys is spaced a minimum amount from its adjacent cooperating pair of parallel pulleys. Thus, the two parallel pulleys and 141 are spaced a minimum amount from their cooperating

angular pulleys

148 and 149. In like manner, the parallel pulleys and 161 are spaced a minimum amount from their immediately cooperating

angular pulleys

168 and 169. The parallel pulleys and 181 of the movable section 82 are likewise spaced a minimum amount from the single pulley that is located on top of the final section 83. The pulleys and their cooperating movable sections are in the position shown because the cable has been taken up by the two drums 131 and 132 so that a minimum amount of cable is within the interior of the boom 30. Such taking up of the cable on the drums 131 and 132 has caused the above mentioned pairs of pulleys to be drawn toward each other for extending the several boom sections relative to each other.

If the drums 131 and 132 are rotated to let out more cable into the interior of the boom 30, the relaxing of the cable will cause the several sections to telescope into each other by gravity. Thus, as the cable 130 is wound off of the drums 131 and 132, the relaxing of the cable will cause the boom section 81 to move into the stationary section 80 and such movement of the section 81 will cause the two angularly disposed

pulleys

148 and 149 which are mounted on the section 81 to move with it to increase their spacing from the two

parallel pulleys

140 and 141, which, as previously mentioned, are rotatably suppported by the stationary section 80. Since the pair of

angular pulleys

148 and 149 are moving away 9 from the pair of

parallel pulleys

140 and 141, the excess cable let off of the drums 131 and 132 is utilized for the increased spacing between the two pairs of pulleys.

When the boom section 81 arrives at its limit of downward movement by gravity, the section 82 will begin telescoping into the section 81 and thereby move its associated pair of angularly disposed

pulleys

168 and 169 `with it to increase their spacing from the pair of

parallel pulleys

160 and 161. The additional cable will therefore be required to accommodate this latter spacing between the two pair of pulleys.

When the movable boom section 82 reaches its downward limit of movement within the interior of its cooperating section 81, additional relaxation of the cable 130 by the rotation of the two drums 131 and 132 will cause the final movable boom section S3 to move downwardly by gravity into its adjacent cooperating section 82. As the section 83 moves downwardly into the section 82, the pulley 185 moves with the section `83 to increase its spacing from the pair of

parallel pulleys

180 and 181. The additional cable that is provided by the rotation of the drums 131 and 132 is utilized to accommodate the increased spacing between the pulley 185 and the pair of parallel pulleys 180` and 181. In this manner the boom 30 is retracted selectively by regulating the rotation of the drums 131 and 132 to let out the desired amount of cable to accommodate the extent of boom retraction that is required.

The downward telescopic movement of the several sections is limited by a plurality of

stops

235, 236 and 237 during the retraction of the boom 30. As depicted in FIGURE 7, the stops are engaged by the

lower support rollers

101, 110 and 120` of the respective sections. Thus a pair of stops 101 are located at the lower end of the stationary section 80 to be engaged by the pair of rollers 101 that are supported by the adjacent cooperating boom section 81. As the movable section 81 retracts into the stationary section r80, the rollers 101 move with it until they engage the pair of stops 235 to terminate further retracting movement of the section y81 relative to the section 80. In like manner the stops 236 are mounted at the lower end of the movable boom section 81 to be engaged by the two rollers 110 that are supported by the movable section 82. When the latter is retracted into the section 81 its associated rollers 110 engage the stops 236 to prevent lfurther retracting movement of the section `82. The stops 237 are fixed to the lower portion of boom section 82 to be engaged by the rollers 120 which are carried by the movable section 83- `for limiting the retracting movement of the movable boom section 83. Although one of each of the

stops

23S, 236 and 237 is shown, it should be understood that another one of each of these stops is mounted on the other side of the same boom section for cooperation with the guide roller that is likewise mounted on the other side of the adjacent boom section.

The extension of the boom sections relative to each other is likewise limited. This can be accomplished by suitable stops but in the illustrated embodiment the limitations are imposed by the pulley and cable system itself by reason of the fact that the parallel pulleys are in the path of travel of the angular pulleys so that the movements of the latter are stopped before the boom sections become extended to an extent which would unduly weaken their carrying capacity.

When it is ldesired to extend the boom 30, the drums 131 and 132 are rotated in the opposite direction to take up the cable 130 onto the drums 131 and 132 so that less cable is Idisposed Within the interior of the boom 30. As the cable 130 is taken up, it can no longer accommodate the increased spacing of the several pairs of pulleys in the manner described above. As a result, the taking up of the cable on the

drums

130 and 131 will cause the pair of

angular pulleys

148 and 149 to be moved closer to their associated pair of

parallel pulleys

140 and 141. Since the angularly disposed

pulleys

148 and 149 are mounted on the -bottom end of the movable boom section l81 and the

parallel pulleys

140 and 141 are carried at the upper end of the stationary section 80, the section 81 will move with the angularly disposed

pulleys

148 and 149 to progressively be extended out of its associated boom section 80. In identical manner, the continued taking up of the cable onto the drums 131 and 132 will produce a telescoping extension of the

boom sections

82 and 83 out of their cooperating boom sections. In this manner the boom 30 is readily extended or retracted by the operation of the two drums 131 and 132 for paying out and taking up the cable 130.

The novel pulley and cable system for extending and retracting the boom 30 in combination with the unique roller arrangement that supports the boom sections for their telescopic movement produces a very eiciently operating boom. It has been -found that the retraction and extension of the boom can be effected while the boom is carrying a very heavy load to greatly increase the versatility of the crane.

The pivotal movement of the boom 30 in a vertical plane about the axis of the shafts 85 and `86 is effected by a winch generally identified by the reference numeral and illustrated in FIGURE 4. The winch 190 comprises a spool 191 that is rotatably supported between the two plates 50 of the column 25. A hydraulic motor 192 is mounted on one of the plates 50 as shown in FIGURE 4 and is connected to actuate a transmission 193 which, in turn, is connected to rotate the spool 191 in either direction of rotation for taking up or letting out a cable which is shown in FIGS. 2, 3 and 6i. With one end of the pulley being attached to the spool 191, the opposite end of the pulley is xed to a bracket 196 that is mounted on the column 25 as clearly illustrated in FIGURE 2. The cable between the bracket 196 and the spool 191 is wound about a series of pulleys for obtaining a mechanical advantage to increase the capacity of the motor 192 for lifting the boom 30 in its pivotal movement and the load attached thereto. The cable and pulley system is secured to the upper end of the boom 30 by a bracket 201 to which an arm 202 is pivotally connected and extends rearwardly therefrom with the opposite end of the arm 202 carrying a pair of

parallel pulleys

203 and 204 having their axes in alignment and in a horizontal plane as best shown in FIGURE 6. Another transverse pulley 205 is carried at the end of the arm 202 with its axis in a Vertical plane. These three pulleys cooperate with a pair of

pulleys

206 and 207 that are journalled in a bracket 208 which is pivotally connected to another bracket 209 that extends upwardly from the top of the column 25. The cable 195 is wound about these tive pulleys in well known 'manner for obtaining a mechanical advantage to facilitate raising and lowering the boom 30 in its pivotal movement in a vertical plane about the two

shafts

85 and 86.

Another winch generally identified by the reference numeral 215 is carried by the column 25 for actuating a cable 216 to raise and lower the load that is being carried by the crane. The winch 215 comprises a spool 217 which has one end of the cable 216 attached to it and is rotatably supported between the two plates 50 of the column 25 so that it may be rotated to take in and let out cable 216 for raising and lowering the load that is being carried by the apparatus. The spool 217 is rotated by a hydraulic motor 217 which is connected to actuate a transmission 218 that is, in turn, connected to the spool 217 for rotating the latter in either direction of rotation to let out or take in the cable 216.

The cable 216 extends from the winch 215 upwardly along the boom 30 over a pulley 220 that is rotatably supported on a stub shaft 221 carried by the bracket 201 as illustrated in FIGURE 6. As shown in FIGURES 2 and 7, the bracket 201 rotatably supports another pulley Z22 that is disposed on the underside of the top of the final section 83 beneath the pulley 220. The cable 216 passes over the pulley 222 as well as the pulley 220 and is provided with a hook 22S at its extending end for attachment to the load that is to be lifted or towed. A chain extension 226 with a hook 227 is illustrated in FIGURE 2 with the boom 30 being shown in its retracted position and the hook 227 being connected to an idler arm 230 for securing the cable 216 and its chain extension 226 when the unit is being moved without a load.

The boom is shown in its retracted position in FIGURE 2 in a pivotable position in which the hook 225 may be readily attached to a vehicle for towing the latter along a desired path of travel. On the other hand, the boom 30 may be extended several times the length illustrated in FIGURE 2 and may be pivoted upwardly in a vertical plane a substantial amount so that loads attached to the hook 225 may be raised relatively great distances and moved about as desired. Thus, the apparatus of the present invention may be operated as a crane with a heavy capacity and extensive range for lifting and moving loads about and yet the boom 30 may be retracted to a short length as to enable the apparatus to be efficiently employed for the purpose of towing other vehicles.

From the foregoing detailed description of the present invention, it will be readily understood that an improved mobile crane and tow truck has been provided in which the telescopic movement of the boom sections has been facilitated by the utilization of rollers for guiding and supporting the boom sections in their telescopic movement relative to each other and the sections are actuated in their telescopic movement by an improved pulley and cable system which cooperates with the roller supports for increasing the capacity, range and maneuverability of the boom. The maneuverability is further increased by extending the boom from rigidly supported rotary column which extends upwardly from the frame to carry the power operated actuating mechanisms as well as the boom. The column is rotated by a unique hydraulically actuated chain drive for swinging the boom in a horizontal direction.

Although the illustrative embodiment of the invention has been described in considerable detail for the purpose of disclosing a practical operative structure whereby theinvention may be practised advantageously, it is to be understood that the particular apparatus described is intended to be illustrative only and that the novel characteristics of the invention may be incorporated in other structural forms without departing from the spirit and scope of the invention as defined in the subjoined claims.

The principles of the invention having now been fully explained in connection with the foregoing description of the illustrative embodiment, the invention is hereby claimed as follows.

I claim:

1. In a crane; `a frame; a plurality of telescoping sections forming a boom for the crane with one of said sections being secured at a pivot to said frame to constitute a fixed section; a plurality of operating pulleys rotatably supported by each of said sections; a pair of guide pulleys rotatably supported at said pivot by said frame; a cable in engagement with said guide pulleys for guiding the cable into said fixed section so that said cable is parallel to said boom when it enters the fixed section to avoid placing any unnecessary lateral loads on said boom, said cable extending from said guide pulleys into operating engagement with said operating pulleys; and means for drawing in and releasing said cable selectively to extend and retract said boom sections.

2. A crane according to claim 1 wherein said boom is pivotable about an axis which is also the axis of rotation of said guide pulleys so that said cable will enter the boom along a line that is parallel to the boom for all angular positions of said boom.

3. A crane according to claim 1 wherein said telescoping sections comprise a bottom fixed section having a top portion and a bottom portion with the bottom portion being coupled to said frame; a succeeding upper intermediate section in telescoping engagement with said fixed section to form the portion of the boom above said fixed section with said intermediate section having a top portion and bottom portion; and an uppermost section at the top of said boom in telescoping engagement with said intermediate section; and said pulleys comprise a pair of top pulleys at the top portion of said fixed section; a pair of top pulleys at the top portion of said intermediate section; a pair of -bottom pulleys at the bottom portion of said intermediate section; and coupling means at the bottom of said uppermost section, the two portions of said cable extending from said winding means being engaged with the pair of pulleys at the top of said fixed section and thence into engagement with said pair of bottom pulleys at the bottom of said intermediate section, the two portions of said cable extending upwardly therefrom into engagement with said pair of top pulleys of said intermediate section and thence downwardly to said coupling means for coupling said cable to the bottom portion of said uppermost boom section; whereby the drawing of said cable causes said pair of bottom pulleys on said intermediate section to be shifted toward said pair of top pulleys of said fixed section for extending said intermediate section outwardly of said fixed section, and said coupling means is shifted toward said pair of top pulleys of said intermediate section for extending said uppermost section outwardly of said intermediate section, and when said cable is released by said drum means said boom sections retract by gravity and said pairs of pulleys separate from each other and from said coupling means.

4. A crane according to claim 1 wherein said telescoping sections comprise said bottom fixed section having a top portion and bottom portion with the bottom portion being coupled to said frame; a succeeding upper intermediate section in telescoping engagement with said fixed section to form the portion of the boom above said xed section with said intermediate section having a top portion and a bottom portion; an uppermost section at the top of said boom in telescoping engagement with said intermediate section; a longitudinal way strip on said bottom fixed section presenting a flat way surface; a roller attached to the bottom of said intermediate section and presenting a fiat peripheral surface in position to ride along the flat way surface of said longitudinal way strip for supporting said intermediate strip in its telescopic movement; a pair of longitudinal way strips formed with each way strip presenting a fiat way surface on said intermediate section; a second roller mounted at the top of said bottom section preventing a fiat peripheral surface in position to ride along the flat way surface of the first of said way strips on said intermediate section for guiding and supporting said intermediate section in its telescopic movement; a roller attached to the bottom of said uppermost section and presenting a flat peripheral surface in position to ride along the flat way surface of the second Way strip of said intermediate section for supporting said intermediate section in its telescopic movement; a single flat way surface on said uppermost section; and a roller carried at the top of said intermediate section and presenting a fiat peripheral surface in position to ride along said single fiat way surface of said uppermost section to guide and support said uppermost section in its telescopic movement.

5. A crane according to claim 4 including a plurality of stops mounted on said telescopic sections for engagement by said rollers to limit the telescoping movement of said sections relative to each other.

(References on following page) 13 14 References Cited 1,345,304 6/ 1920 Zied 212-55 UNITED FOX et al. 916,317 3/ 1909 Hood@ 212-59 ANDRES H. NIELSEN, Primary Examiner. 1,345,304 6/1920 Zied 212-55 5 2,833,422 5/1958 Ferwerda et al. 212--55 U.S. C1. X.R.

3,029,954 4/1962 Grant 212-55 212-144