US3487893A - Nested mast sections with rollers and means permitting assembly and disassembly - Google Patents

Description

Jan. 6, 19%) N J, RYSKAMP @Akfiifi NESTED MAST SECTIONS WITH ROLLERS AND MEANS PERMITTING ASSEMBLY AND DISASSEMBLY Filed June 5, 1968 United States Patent 3,487,893 NESTED MAST SECTIONS WITH ROLLERS AND MEANS PERMITTING ASSEMBLY AND DISASSEMBLY Neil J. Ryskamp, Markham, 11]., assignor to Allis-Chalmers Manufacturing Company, Milwaukee, Wis. Filed June 5, 1968, Ser. No. 734,674 Int. Cl. B66b 9/20, 7/02 US. Cl. 187--9 7 Claims ABSTRACT OF THE DISCLOSURE This invention relates to means for permitting assembly and disassembly of mast sections of a lift truck.

Heretofore, others have provided nested mast sections with rollers to facilitate relative movement therebetween. In these prior constructions it is usually to provide cutout portions in the flanges of the mast section uprights to facilitate assembly and disassembly. However, such prior art arrangements have not been entirely satisfactory in that the uprights have been weakened by the cutouts; and, additionally, the upright has been subjected to the torsional loading of the roller mounted at its upper end at a position adjacent the cutout. Thus, the upright is subjected to its roller loading in the area where it is weakened by the cutout.

It is an object of the present invention to provide an improved means for permitting assembly and disassembly of lift truck mast sections.

It is a further object of the present invention to provide shiftable roller supporting mean on the primary or outer mast section and cutout portions in the secondary mast section to permit assembly and disassembly without the requirement of cutout portions in the primary mast uprights.

It is a further object of the present invention to provide means for assembly and disassembly of a pair of inner and outer mast sections which is economical to manufacture, easy to service and has long trouble-free life.

It is a further object of the present invention to provide a roller mounting on a mast upright which facilitates assembly and disassembly of the mast sections and avoids subjecting the web of the upright to twisting stresses.

These and other objects and advantages of the present invention will be apparent to those familiar with the art when the following description is read in conjunction with the drawings in which:

FIG. 1 is a side view of a lift truck incorporating the present invention;

FIG. 2 is an enlarged top view of the mast of the truck of FIG. 1 with parts broken away;

FIG. 3 is a side view of the mast shown in FIGS. 1 and 2 and illustrating the inner mast section in its extended position; and

FIG. 4 is an isometric view showing parts of the inner and outer mast sections being disassembled.

Referring to FIG. 1, the present invention is incorporated in a lift truck 11 having a pair of drive wheels 3,487,893 Patented Jan. 6, 1970 12 at its forward end and a pair of steerable wheels 13 at its rear end. The lift truck 11 is provided with an operators station 14 at which a conventional steering wheel 16 is located. A mast 17 is mounted on the forward end of the lift truck 11 and reciprocally carries the load carriage 18 to which a pair of forks 19 are attached. Referring also to FIGS. 2, 3 and 4, the mast is comprised of a primary or outer section 21, which includes a pair of uprights 22, 23, and a secondary or inner mast section 26 having a pair of uprights 27, 28. The outer mast section 21 includes a transverse cross brace 31 made up of a hollow cylindrical portion 32 rigidly secured, as by welding, to a pair of brackets 33, 34 which are in turn welded to the rear sides of flanges 36, 37 of uprights 22, 23. As shown in the drawings, the uprights 22, 23 are channel-like in shape having channels 38, 39 in inwardly facing relation to one another. Such channels 38, 39 are defined by flanges 36, 41 interconnected by a web 42 and flnages 37, 43 interconnected by a web 44. Appropriate means, not shown, are employed to brace the primary uprights 22, 23 at their lower ends.

The uprights 27, 28 of the inner mast section 26 are also channel-like in shape with their channels 46, 47 facing inwardly toward one another. The upright 27 includes a pair of inwardly extending flanges 51, 52 interconnected by a web 53 and a laterally outward extending flange 54 which is disposed within the channel 38 of outer upright 22. Similarly, inner upright 28 includes inwardly extending flanges 56, 57 interconnected by a web 58 and an outer flange 59 which extends into the channel 39 of outer upright 23.

A pair of rollers 61, 62 are mounted on the bottom ends of the inner uprights 27, 28, respectively, at the laterally outer sides thereof. These rollers are disposed within the channels 38, 39 where they make rolling load bearing contact with flanges 36, 37, respectively. A pair of upper rollers 66, 67 are swingably supported on the upper end of the outer mast section by a pair of links 68, 69, respectively. As shown in the drawings, the rollers 66, 67 are rotatably connected to the free ends of the links 68, 69; and the links, in turn, are pivotally connected to the transverse brace 31 through a shaft 71 extending through cross brace 32. The shaft 71 has its opposite ends fixed to the rear end of the links 68, 69 by appropriate pins 72, 73. By employing the upper rollers 66, 67 on links, as illustrated, the load to which they are subjected, through their rolling load carrying contact with the outwardly extending flanges 54, 59 of the inner mast uprights, is carried by the cross brace 31 rather than by the webs 42, 44 of the outer mast uprights. Thus, the primary uprights 22, 23 have been freed of forces which heretofore have caused detrimental distortion of the primary uprights.

When the secondary mast section 26 is raised to its extended position, abutments, in the form of stops 81, 82 secured to the inner uprights 27, 28 by cap screws 83, will contact abutments in the form of surface 86, 87 on brackets 33, 34, respectively. The abutments limit the extension of the inner mast section during operation of the lift truck. If it is desired to disassemble the mast sections, the abutments 81, 82 are removed, and the inner mast section is then moved to its fully extended position illustrated in FIG. 4 wherein cutaway portions 91, 92 of flanges 54, 59 register with rollers 66, 67 to permit the passing of rollers 66, 67 therethrough. A pair of side thrust rollers 101 are provided for rolling contact with the webs 42, 44 of the outer uprights. Only one of the rollers 101 is illustrated; however, it should be understood that the other roller is similarly constructed. FIG. 4 is also illustrative of the position of the uprights at the time they are being assembled.

From the foregoing description, it is apparent that a new and useful means has been provided to conveniently permit assembly and disassembly of mast sections. It should also be readily apparent that the mounting for the upper rollers on the outer mast section improves the distribution of forces to obviate distortion of the primary uprights that might otherwise occur.

The embodiments of the invention for which an exclusive property or privilege is claimed are defined as follows:

1. A lift truck mast comprising:

a first mast section including an upright having a web and flanges defining a channel,

a second mast section including an upright having a web and a flange extending into said channel, said flange having a cutaway portion at its lower end,

a roller secured to the bottom of said second upright and extending into said channel,

a link pivotally connected at one end to said first mast section upright adjacent the upper end thereof for pivotal movement about a transverse axis,

a roller secured to the other end of said link in rolling engagement with said flange on said upright of said second section,

said roller on said link passing through said cutaway portion when said second upright is in its fully extended position, and

cooperating abutments on said mast sections, respectively, preventing said second mast section from being moved to its fully extended position, and

releasable fastening means securing one of said abutments to one of said mast sections, said second mast section being movable to its fully extended position when said one abutment is removed.

2. The invention in claim 1 wherein said first mast section includes a cross brace at its upper end and wherein said link is pivotally connected at its said one end to said cross brace.

3. The invention of claim 2 wherein said one abutment is secured to said upright of said second mast section, and the other of said abutments is formed on said cross brace.

4. The invention of claim 1 wherein said flanges on said upright of said first mast section are uninterrupted adjacent the upper end thereof.

5. The invention of claim 1 wherein said mast sections each have a pair of channel-shaped uprights with the channels of each upright pair facing one another and wherein said second section uprights each have an outwardly extending flange.

6. The invention of claim 5 wherein said first mast section includes a transverse cross brace rigidly interconnecting its pair of uprights at their upper ends, wherein a pair of links have their corresponding ends connected to said cross brace and wherein rollers are mounted on the free ends of said links in rolling contact with said outwardly extending flanges.

7. The invention of claim 6 and further comprising a shaft journaled in said cross member and means securing said corresponding ends of said links to opposite ends of said shaft.

References Cited UNITED STATES PATENTS HARVEY C. HORNSBY, Primary Examiner U.S. Cl. X.R=

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