US2739716A - Carbody - Google Patents

Description

March 27, 1956 J. w. POULTER CARBODY 4 Sheets-Sheet 1 Filed Aug; 9, 1951 NVENTOR.

March 27, 1956 J. w. POULTER CARBODY 4 Sheets-Sheet 2 Filed Aug. 9, 1951 INVENTOR.

March 27, 1956 J. w. POULTER 2,739,716

CARBODY Filed Aug. 9. 1951 4 Sheets-Sheet 3 I N V EN TOR.

f -Mww March 27, 1956 J- w. POULTER 2,739,715

CARBODY Filed Aug. 9. 1951 4 Sheets-Sheet 4 IN V EN TOR. JB/m/ W Po uLIr'E nited 2,739,716 Patented Mar. 27, 1956 CARBODY John W. Poulter, Milwaukee, Wis, assignor to Koehring Company, Milwaukee, Wis., a corporation Application August 9, 1951, Serial No. 241,124

4 Claims. (Cl. 212-69) This invention relates to improvements in crane and shovel machines and more particularly to a certain component thereof, the particular component being designated a carbody.

In the usual crane or shovel construction, the same is comprised of what is known as an upper swing body or cab carried by a turn-table in which is supported the machinery for operating the various instrumentalities of the crane including the traction supporting arrangements. In such crane or shovel construction, the same usually includes a boom extending therefrom and pivotally connected to the swing body, the body in turn being rotatably supported upon the carbody, and the carbody in turn being carried upon endless tracks or crawlers generally, although in certain cases, the crawlers may be replaced by other types of traction supporting gear.

With the upper body rotatable upon the carbody into various positions with respect thereto and with respect to the tracks or crawlers which support the carbody, certain unusual strains or stresses are imparted to the carbody, and it is one of the main purposes of this invention to so construct the said carbody as to withstand the strains and stresses without fracture or rupture of the various components thereof.

Heretofore such carbodies have in general been constructed of very large cast members, which cast members are expensive and subject to rupture under certain conditions.

It is therefore a more particular concept of this invention to provide a carbody which may be built up of welded sections, the various components of the sections being suitable types of steel.

However the construction of a carbody by welding often results in a member which is not satisfactory because of the possibility of fracture of the welds due to stresses imparted during certain manipulations of the upper structure with respect to the body, and therefore it is essential that the carbody be designed to withstand the stresses and at the same time not permit the fracture or rupture of welded sections or joints comprising the same.

It will be of course obvious that construction of a carbody such as is disclosed herein, by welding will materially reduce the cost as opposed to the use of a cast member, and at the same time materially facilitate the manufacture thereof if a suitable welded structure is provided, such as is described herein.

It is therefore a principal object of this invention, to provide a carbody, which may be constructed by welding various steel sections together, and at the same time include therein certain cast members which are most particularly suitable for the objects or purposes which they fulfill in machines of the class to which this invention is directed.

It is a still further object of this invention to provide a welded carbody wherein distortion of the same during digging operations of the crane or other structure with which the same is used, resulting in fracture or rupture of welded joints, from twisting and other strains imparted to the carbody, is eliminated.

It is a further object of this invention to provide a welded carbody, wherein the necessity for additional bracing other than that which is included in the carbody itself, is unnecessary, and at the same time to counteract certain stresses which are set up during digging operations.

In view of the necessity for including in the carbody itself certain provisions for supporting driving shafts and gearing, which gearing and driving shafts must be accessible, it is a further object of this invention, to so construct a carbody whereby the various operating parts included therein are accessible without removal of extraneous bracing or other supporting means which would normally possible be availed of to eliminate fracture due to stresses set up in the carbody during operation.

A still further object of this invention is to so construct a carbody that the stresses normally set up during operation of a machine in which the same is incorporated, are distributed uniformly relatively throughout the carbody and concentration of stresses therein is relatively unimportant, from the standpoint of fracture of welded joints availed of and at the same time a rigid unit is provided inwhich accessibility of various parts comprising the same is attained, together with other known advantages arising from availing of welding technique.

Other and further objects of this invention will be understood from a consideration of the specification appended hereto, taken in conjunction with the drawings, wherein;

Figure 1 is a top plan view of a carbody constructed in accordance with this invention, illustrating in general the various parts comprising the same, as welded together, together with portions of the supporting axles which are normally attached to crawler or track-type supporting gear.

Figure 2 is asectional view taken about on the line of 2--2 of Figure 1, illustratingthe various components of the structure, together with the assembled relation of the same.

Figure 3 is a fragmentary sectional view taken about on the line 33 of Figure 1, illustrating certain of the parts of the structure.

Figure 4 is a side-elevation view, in perspective showing the carbody and certain of the welded joints availed of when constructing the same.

Figure 5 is a bottom view in perspective, of the carbody illustrating the gear case and driving axle supporting means, together with certain of the bracing features, availed of in the carbody.

Figure 6 is a diagrammatic view, used for purposes of illustration to describe certain stress relationships.

Figure 7 is a further diagrammatic view relating to Figure 6, to assist in analysis of stresses counteracted by the construction of carbodies described herein.

Figure 8 is a diagrammatic view looking at the top of the crane construction with which the carbody may be associated, and illustrating one of the positions in which certain of the maximum stresses are set up which normally cause, by concentration thereof, the maximum amount of distortion.

Figure 9 is a top plan view showing the side and end plates in their related position and omitting the balance of the structure.

Figure 10 is a fragmentary sectional view taken about on the line Ill-10 looking in the direction of the arrows in Figure 9, and further illustrating the form of the end plate in cross section.

Figure 11 is a top plan view of one of the end plates before assembly.

Figure 12 is a top plan view of one of the side plates before assembly.

Figure 13 is a bottom plan view showing the main frame member before assembly.

Figure 14 is a sectional view, showing the main frame member and its relation to other members of the assembly, the section being taken about on the 14-14 of Figure 13.

By way of explanation, certain of the problems arising with relation to welded carbody construction, will be discussed in conjunction with the illustrations, diagrammatically, in Figures 6, 7 and 8 of the various forces resulting during operation of a crane or shovel. It has been found that cracks which may develop in a welded carbody construction are largely due to concentration stresses which are caused by a change in the diagonal dimension of the carbody, these stresses being secondary but occurring during the digging operation when the upper body is turned to a certain position with respect to the crawlers or other traction members, which support the machine. More specifically, in Figure 8 there is diagrammatically illustrated one of the positions which has been found to cause the largest amount of difficulty and which position is common during digging operations, and which result from the tilting to a certain extent of the whole machine, whereby the weight of the complete machine plus the digging effort, is supported at one end of one crawler frame.

A brief analysis of the loading on the carbody can be made in reference to the disclosure of Figure 6. Under certain conditions, it is possible to get a combined weight and digging effect of 240,000 pounds at B. Assuming that the distance from B to C along the line DE is equal to twice the distance from B to A along the same line, then this 240,000 pounds will be divided so that the force at C will equal 80,000 pounds and thus the force at A will be 160,000 pounds.

Referring to Figure 7, taken in conjunction with Figure 8, it will be assumed that B comes directly over the middle of one of the shoes in the crawler, and F' indicates the general location of the front turntable rollers with respect to the front of the carbody. Then assuming that the relationship along GH from B to F and from F to I will be in the ratio of one to two or the same as AB and BC along DB in Figure 6, then the reaction at C and that at I are opposed by the rear hook rollers at a general location on the roller path 180 from F. This causes a diagonal springing or strain in the complete carbody unit, which in turn, tends to produce a change in the lower diagonal dimension of the carbody itself. Distortions of as much as plus to minus /a have been measured in previous types of carbodies. This amount of deflection results in abnormally high stresses in the lower section of the side and end members which are availed of in the carbody, and particularly so at their junctions at the corners.

As the description of the carbody of this invention proceeds, the above analysis will be understood, as the same has been availed of in properly constructing the carbody, so as to reduce the distortion and the various stress concentrations which have been discussed. It will furthermore be understood that analysis has enabled the construction of the carbody, so as to include within the same the necessary reinforcing members to counteract the stress concentration and thus obviate fractures under extreme conditions, without resorting to extraneous bracing members which would interfere with the operation of the machine under certain conditions, and furthermore, handicap repair or replacement of parts availed of therein, the welds being located at less seriously stressed points.

With the foregoing explanation of the problems confronted in design and construction of a welded carbody, reference will now be had to the other figures in the drawings, illustrating a form of carbody which counteracts.

and resists strain and fracture due to the stresses set up, and at the same time results in a compact unitary-structure which does not necessitate availing of extraneous bracing or other means in order to counteract the stresses and stress concentration normally resulting in a structure such as is described herein.

Referring to Figure 13 and 14 initially, certain of the main parts of the main frame are shown, and particularly the main carbody frame member 1 is seen to comprise a substantially rectangular heavy metal member cut in the outline of Figure 13. This member 1 consists .of the front or end section 2 rear or end section 3 and side sections 4 and 5, all lying in substantially the same plane.

Integral therewith and extending out of the plane are the arched brace arms generally denoted 6 and 7.. The

' arm 6 is comprised of the parts 8 and S which converge It should be noted that all of the parts thus far described are formed out of a single flat plate member ini: tially, with the necessary portions-cut out thereof, including the openings at the front and rear and at the opposite sides. Suitably mounted on the opposite side members are the drive shaft supporting bearing units 12 and 13, which bearing units are intended to support a drive shaft for transferring the drive from a transmission gear case, generally designated 14, located substantially centrally of the main frame member to the crawlers.

Referring now to Figure 2, it will be noted that the arched brace arms 6 and 7 are formed so as to extend upwardly and inwardly with respect to the main frame member 1 of which they are integral parts and are welded securely to a top plate 15 at their inner ends which are comprised of the ends of the members 8, 9 and 10, 11, and as indicated at 8-a and Ill-a for example in Figure 5, and also to a central pivot-bearing designated 16, having an enlarged lower portion 16a which forms the top of the housing or gear case 14. This central pivot bearing is preferably formed of a suitable casting and is also welded.

to the top plate member 15, and extends upwardly therefrom. Also suitably welded to the top plate member 15 and thereabove, is the roller path and ring gear designated 17, the same being also a suitable casting, and including therein the ring gear in accordance with conventional construction.

In Figure 13 the main frame member is shownas though removed from the assembly in order to moreparticularly illustrate its form. It will be noted that the end portions 8b and 9b which are fixed by welding to the top plate 15, are separated by the arcuate section .80 which is secured to the enlarged lower portion 16:: of the pivot bearing 16. Similarly the end portions 1% and 11b of the brace arm 7 are provided for securing the same to the top plate 15 at the opposite sideof the pivot bearing 16, the arcuate section formed so as to be welded to the lower portion 16a of that hearing.

In Figure 14, the manner in which the arms 6 and 7 are bent upwardly out of the plane ofthe body 1 is more clearly illustrated. In this figure the top plate 15 is shown in position, and the central pivot bearing 16 indicated in dotted lines in the position in which it is fastened toboth the top plate and arched brace arm.-

Suitable vertical side and end plates designated 18 and at the upper edges as at 21 to the top plate It will be.

apparent as illustrated in the respective drawings of figures, the side plates are suitably molded or otherwise formed so as to provide for welding of the same to the round or circular top plate member 15, and securely support the same. Additionally, it will be apparent that the end plates 19 are similarly formed so as to be welded at 22 to the member 1 and at 23 to the top member 15, similarly to the welding of the side plates 18.

In order to provide means for securing suitable axles designated 24 and 25 in the Figure l to the carbody, suitable bosses designated 26 are welded as at 27 to the main frame member 1, and extend thereabove. These bosses 26 are also welded to the side and end plates, as at 28 and 29, and are therefore substantially integral with those members and stiffened thereby. It will be apparent that the respective side and end plate members 18 and 19 are suitably formed at their respective ends so as to properly engage the bosses 26 for welding thereto as at 28 and 29 to afford the necessary connection and stiffening as previously mentioned.

It should also be mentioned that the roller path and ring gear member is suitably Welded at 30 to the upper face of the top plate 15, and additionally provides stiffening for the unit as a whole.

The central gear case or housing 14 is preferably formed of suitable plate members and Welded to the arched brace-arms as at 31, providing additional stiffening therefor, without the requirement for internal bracing within the gear case, the usual flange 32 in turn being welded at the lower portion of the gear case 14 as at 33. It will be apparent that the cover, shown in Figures 4 and 5 and designated 34 may be suitably fastened to the mounting flange 32 by bolts 35. Also shown in the various figures are the bearings provided for the drive shaft and formed so as to be attached by welding to the flange as at 36, the bearing half for the gear case being suitably fastened to the flange and the other half of the bearing being included in the cover 34.

Suitable braces in the form of what may be termed bows or specifically termed radial brace plates are provided as shown in Figure l, at opposite sides of the carbody. The radial brace-plates are designated 37 and 38, and extend from bosses at opposite ends of the main frame member as shown in the said Figure 1, being suitably welded at their lower edges to the bosses and to the arched brace arms as at 39 in Figure 3. These radialbrace plates are welded at their upper portion to the side end plates as at 40 and to the top plate 15 as at 41. It will therefore be apparent that these vertical plate members afford substantial rigidity throughout the structure and assist in tying the whole structure together as a unit.

In view of the foregoing description of a welded carbody, it will be apparent that there is hereby provided a carbody construction which relieves stress concentration and furthermore maintains the carbody in its original shape so as to prevent diagonal distortions thereof, and yet the same is comprised of relatively few parts of simple conformation.

Where reinforcing members are merely added to a structure, the stress concentrations are generally accentuated if the entire unit is not redesigned.

In earlier welded carbodies reinforcing of the lower section of the side and end members caused them to carry more and the upper part less of the loading, or if a side or end member only was reinforced, the adjacent members were subjected to higher stress.

This was therefore a primary consideration in the design of the subject invention and while straight diagonal bracing would theoretically relieve such concentrations, it could not be availed of because of the gear case at the center of the carbody, and reinforcing the casing was found to be impractical.

As heretofore indicated the loading in diagonal braces would be of the opposite sign in view of the tendency to shorten the diagonal dimension in one direction with resultant elongation in the other direction. These loadings are approximately equal and it was therefore found that by constructing the arched braces 6 and '7 so that they go over the gears and the housing ild, the downward component of opposite brace arms 1% and 11 is balanced by the upward component of the other brace arms 9 and 10. Furthermore the brace arms 8 and 9, and 1t) and 11 may be in the same respective planes at opposite ends without resulting in any objectionable stress condition.

Having thus shown and described my invention what I claim as new and desire to secure by Letters Patent of the United States is:

l. A carbody of the class described comprising, a main frame member, a top plate spaced above said main member, a central pivot bearing including a gear case top member, welded substantially centrally to said top plate, said main frame member including brace arms integral therewith extending to said top plate and welded to said top plate and said gear case top member, a main gear case member welded to and beneath said brace arms, side and end plates extending from said main frame member to said top plate and welded thereto, and a roller path fastened to and above said top plate.

2. In a carbody of the class described, a substantially rectangular main frame member including side and end members lying in substantially the same plane, bearing means fixed to said side members, a main gear case member having bearing means aligned with the bearing means in said side members, said gear case member extending substantially above the plane of said side and end members, a top plate spaced from main frame member and substantially parallel thereto, a central pivot bearing and top gear case member fixed to said top plate, an X-shaped brace member intgeral with said main frame member at its outer opposite ends and fastened at its central portion to the top plate and cover member, said main gear case member being fixed at its upper end to and beneath said central portion, and side and end plate members fixed to said side and end members of said main frame and to the top plate aforesaid.

3. A carbody as claimed in claim 2, wherein bosses are fixed to the main frame member at opposite ends of the side members thereof, radial brace plates are fastened at their ends to said bosses and extend along and are fixed to the said X-shaped brace member, said radial brace plates being also fixed to said top plate and to the end and side plates near the juncture thereof, and the side and end plates are fixed to said bosses at their adjacent ends.

4. In a carbody of the class described, a main frame member including side and end members lying substantially in the same plane, a top plate spaced therefrom and substantially parallel thereto, an arched brace comprising brace members integral at their outer ends with said main frame member and fastened at their inner end to said top plate, a central pivot bearing formed with a gear case top member fixed substantially centrally in said top plate, said brace arms being fastened to said gear case top member, side and end plates fixed to said main frame member and said top plate and extending therebetween, and a main gear case member fixed to and below said brace arm.

References Cited in the file of this patent UNITED STATES PATENTS 2,035,385 McLean Mar. 24, 1936 2,134,866 Esters Nov. 1, 1938 2,144,760 Harnischfeger Jan. 24, 1939

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