US2706120A - Floor crane with adjustable legs - Google Patents

Description

P" 1955 R. R. STRATTON FLOOR CRANE WITH ADJUSTABLE LEGS 2 Shets-Sheet 1 Filed June 19, 1951 7 5 5 w d w. a a a T l l w m T. 5 T ,v I 7 7 u 1 3 1 f V an. m m a ll. 0 a 7 n, a F1 8 o- Z M x m a I 5 AM a Z 2 6 v 5 2 2 2MB .2 5 n j a fiztk. 3m 9 4 a /V 1 l 52 6 8 f 9 5 a W H 9 4 1 l 4 a A 7' TOQ/VEYS.

A ril 12, 1955 R.- R. STRATTON 2,706,120

FLOOR CRANE WITH ADJUSTABLE LEGS Filed June 19 1951 2 Sheets-Sheet 2 J9 J5 64 61 J/ 'lllnllllufllllliln I INVENTOR.

Po/vAm A? 5 7 7 70 BY United States Patent Office 2,706,120 Patented Apr. 12, 1955 FLOOR CRANE WITH ADJUSTABLE LEGS Ronald R. Stratton, Cleveland, Ohio, assignor to Stratton Equipment Company, Cleveland, Ohio, a corporation of Ohio Application June 19, 1951, Serial No. 232,337

3 Claims. (Cl. 280-35) This invention relates to a floor crane and, more particularly, to a floor crane characterized by a high degree of adaptability to a variety of different uses.

In automotive repair shop practice, as, for example, in shops for repairing automobiles, trucks, tractors, etc., it is usually considered desirable to have a floor crane available for lifting engines and other heavy parts; at the same time, it is usually desirable to have the crane readily maneuverable and of such dimensions that it can pass through doorways of ordinary widths. The usual crane that is designed to pass through doors of ordinary widths cannot be used in certain situations because the legs are too close together to permit the crane to be placed in position to lift the load; while heavy-duty cranes of larger dimensions are generally too wide to pass through the usual shop doorways. A floor crane that is both maneuverable and adaptable to various purposes is desirable in automotive repair shops and other shops.

Accordingly, it is an object of the present invention to provide a floor crane that is readily maneuverable through shop and like doors of ordinary widths, and that also can be used where wide-spread legs are required in order to put the crane in position for lifting. To that end, the invention provides a floor crane characterized by legs which in normal position parallel the boom but nevertheless are susceptible of being adjusted to a variety of positions in each of which they can straddle obstructions wider than the normal space between the legs. It is of course quite necessary that the floor crane be so constructed that when the legs are spread to straddle a wide object of this sort, the inherent stability of the crane will successfully resist any tendency to upset.

A further object of the invention contemplates the provision of means for adjusting the legs to any one of a relatively wide variety of positions in certain of which the crane as a whole will be of narrow width, thereby permitting it to pass through doorways of ordinary dimensions, and in others of which the fioor crane will have the capacity for straddling wide objects. To this end, the invention provides simple, foolproof adjusting means by which, when the desired adjustment has been effected, the same can be retained as long as desired,

after which the adjustment may by a very simple manual operation be modified to provide a greater straddle, a lesser straddle, or no straddle at all except such as characterizes the retracted position of the legs. It is of course desirable that the adjustment be susceptible of being made quickly without undue trouble and the invention provides adjusting means designed with this and like considerations in mind.

It is a further object of the invention to provide a floor crane of light but sturdy construction in which there is extensive surface contact between the platform mounting the superstructure and those parts of the legs which cooperate with the platform. To that end, the invention contemplates the use of legs of a shape such that the upper and lower surfaces thereof bear with limited clearance against the elements making up the top and bottom of the mast-mounting platform. This construction has the advantage that there can be dissemination over a wide area of forces transmitted from one part to another, thereby permitting the use of an extremely simple pivotal connection at the points where the legs are coupled to the platform.

A further object of the invention is to provide a substructure for the floor crane which is of built-up construction but which will nevertheless have adequate rigidity to resist bending forces, together with a degree of strength of the order of that usually found only in sub-structures of much heavier construction. To that end, the platform mounting the superstructure preferably consists of a simple base plate serving as the top of the platform, a suitable bottom structure, and, between them, web-like reinforcing means including a web-like shield surrounding the greater part, but less than all, of the periphery of the platform. The leg structure, including the means for housing the casters at the rear of the legs, likewise is of built-up construction. The inner ends of the legs are also of built-up construction and, as previously mentioned, especially designed to provide extensive surface contact with overlying and underlying parts of the platform.

Other objects and advantages of the invention will be apparent from the description which follows and from the accompanying drawings, in which Figure 1 is a top plan of a floor crane incorporating the teachings of the invention; Figure 2 is a corresponding side elevation; Figure 3 is a corresponding bottom plan; Figure 4 is a sectional elevation on a somewhat larger scale as seen from line 4-4 of Figure 2; and Figure 5 is a section with parts in elevation, on the same scale as in Figure 4, as seen from line 5-5 of Figure 1.

In the drawings, Figures 1, 2 and 3 show, among other things, a mast-supporting platform generally designated 1. Mounted on platform 1 is a mast 2 characterized by a hollow portion 2a that serves as a reservoir for oil or some other suitable hydraulic fluid and, above hollow portion 2a, by a block 2b on which is mounted a boom 3. At the unsupported end of boom 3 are the usual chain 4 and hook 5. At a point intermediate its two ends, boom 3 is connected to a piston rod 6 on the lower end of which is carried a piston (not shown) that coacts with a hydraulic cylinder 7 supported by means of a yoke 8 on an upright mounting plate 9. Apart from platform 1, all of the elements of the superstructure so far mentioned, and also certain of the elements hereinafter mentioned, are of conventional construction.

As appears from Figures 1 and 2 of the drawings, platform 1 incorporates a substantially flat base plate 11 to the upper face of which is welded, in addition to mast 2 and mounting plate 9, a hand-operated pump assembly generally designated 12, such pump assembly including an operating handle 13. Between hollow portion 2a of mast 2 and pump assembly 12 is a first hose connection 14, such connection being shown in Figure l. Extending from pump assembly 12 toward cylinder 7 is a second hose connection 15 terminating in a regulator 16 which is connected to the lower end of cylinder 7 and from which a third hose connection 17 leads to a valve 18 rigidly mounted on and in communication with hollow portion 2a of mast 2. Back of valve 18 as seen in Figure 2 is a fourth hose connection 19 connecting hollow portion 2a of mast 2 and the upper end of cylinder 7 at a point above the piston carried by piston rod 6.

Welded to base plate 11 and extending forwardly from mast 2 is an upright mounting plate 21 to which is pivotally connected a T-handle 22 which is bifurcated at its lower end to permit it to straddle mounting plate 21. Mast 2 is strengthened by a vertical stiffening flange 23 welded to it in the relation shown in Figure 2. Welded to and extending forwardly from stiffening flange 23 is an inclined brace 24 of bar stock which passes through the bifurcated portion of T-handle 22, such brace being welded at its lower end to base plate 11. Extending laterally in opposite directions from mast 2 are two inclined tubular braces 25 and 26, such tubular braces being welded at their upper ends to hollow portion 2a of mast 2 and at their lower ends to base plate 11.

Base plate 11 has a forwardly extending portion of semi-circular form which forwardly extending portion is designated 27 in Figure 1. It also has a rearwardly extending portion designated 28, such rearwardly extending portion taking the form of a shallow rectangle. The two portions 27 and 28 are not separate but integral with each other, being part of the same piece of stock. Depending from base plate 11 as shown in Figure 2 and extending rearwardly in both directions from the front end of platform 1 is a web-like shield 29 of the nature of an apron. Shield 29 is welded to the lower face of base plate 11. It is co-extensive with it except near the squared-01f trailing edge 28a at the rear of the base plate, where it stops short of such trailing edge. Shield 29, which thus encompasses the greater part of the periphery of platform 1, provides a measure of protection for the two caster assemblies 31 shown in Figure 3.

Caster assemblies 31, each of which is mounted on the lower face of base plate 11 and includes a caster wheel 32 mounted for free swiveling movement through an arc of 360, support and impart mobility to platform I.

As appears from Figure 3, the lower face of base plate 11 is further provided with a triangular reinforcing web 33 and a forwardly extending reinforcing web 34, both of which are welded to base plate 11. Triangular reinforcing web 33 is made up of three like portions 33a, 33b and 330. The latter 33c, is at the rear and blocks off a large part of the area behind shield 29, which area would otherwise be open from the back. Together,

triangular reinforcing web 33 and forwardly extending reinforcing web 34 divide the lower face of base plate 11 into compartments, of which there are two like compartments, one a mirror image of the other, in side-byside relation. It is in these compartments that the caster assemblies are mounted. A horizontally extending reinforcing plate 35, shown as rectangular in Figure 3. is used to interconnect parts 33a, 33b and 33c of triangular reinforcing web 33, thus forming a part of and further stiffening the reinforcing system underlying base plate 11. Along with other elements about to be described, reinforcing plate 35 goes to make up the bottom structure of platform 1.

As shown in Figure 3, triangular reinforcing web 33 is flanked by polygonal reinforcing plates 36 and 37. The latter are in the same plane as rectangular reinforcing plate 35 and, like it, go to make up part of the bottom structure of the platform. They extend outwardly to web-like shield 29 from triangular reinforcing web 33 and rectangular reinforcing plate 35, being welded thereto along their outer and inner edges. As appears from Figure 2 of the drawings, flanking plates 36 and 37 extend rearwardly somewhat beyond the limits of the rearwardly extending parts of web-like shield 29, terminating directly below the squared-off trailing edge 28a of base plate 11. This construction provides immediately above flanking plates 36 and 37 two open-ended pocket- like chambers 38 and 39, best shown in Figure 4. Such chambers, which are considerably wider at the forward ends than at the rear ends thereof, terminate at the rear of the platform in the plane of part 330 of triangular reinforcing web 33.

In substantially this same plane are located pivot pins 41 and 42, which take the form of incompletely threaded bolts or similar elements having heads 41a and 42;: that can bear upon base plate 11 just forward of trailing edge 28a. Pivot pins 41 and 42 pass through pairs of aligned openings (not shown) in base plate 11 and flanking plates 36 and 37. They are long enough so that their threaded portions, which are at the lower ends thereof, project through flanking plates 36 and 37 as shown in Figure 4, thus permitting nuts 43 and 44, which are preferably of the self-locking type, to be applied thereto. Pivot pins 41 and 42 are provided in order to mount and impart a capacity for swinging movement to stabilizing legs 45 and 46, the inner ends of which project into chambers 38 and 39, respectively. These simple pivot pins are adequate for the purpose in view of the fact that, as will appear, the construction of the platform and legs imposes on them only relatively light loads. If the construction of the platform and legs were diiferent, pivot pins of the nature of king pins might be necessary.

Each of legs 45 and 46 consists as shown in Figures 4 and of a relatively wide downwardly facing upper channel member 47 interiorly stiffened by means of a plate 48 that is welded to the horizontal portion thereof and a relatively narrow upwardly facing lower channel member 49 that is similarly stiffened by means of a plate 50. Lower channel member 49 tits closely within and is welded to upper channel member 47 to provide a highly rigid construction. Aligned holes (not shown) for pivot pins 41 and 42 are drilled through upper channel member 47 and stiffening plate 48 and lower channel member 49 and stiffening member 50, such holes being arranged to register with aligned holes (not shown) in base plate 11 and flanking plates 36 and 3"] where pivot pins 41 and 42 pass through platform 1.

By locating the holes in base plate 11 and flanking plates 36 and 37 substantially in the plane of part 330 of triangular reinforcing web 33, they are removed slightly from the rear extremities of platform 1 but nevertheless in a position to permit relatively wide swinging movement of the opposite ends of legs 45 and 46 between limits indicated by the solid-line positions, in which they parallel boom 3, and the outwardly-angled positions represented by dotted lines 45' and 46' in Figure 3. Legs 45 and 46 can be swung outwardly to an extent greater than that indicated by the dotted-line positions, such relatively wide outward swing being made possible by the fact that chambers 38 and 39 are wider at their forward ends rather than at the rear thereof and the fact that web-like shield 29 terminates as previously explained some distance short of the ends of base plate 11 and flanking plates 36 and 37. The straddling of wide obstacles thus becomes possible.

By locating pivot pins 41 and 42 as shown in the drawings, it also becomes possible to permit the inner ends of legs 45 and 46 to project inwardly for a considerable distance within pocket- like chambers 38 and 39. The fit of legs 45 and 46 therein is a close fit with only a slight overall clearance with the result that there is extensive area contact between each of legs 45 and 46 on one hand and, on the other, the portions of base plate 11 and fianking plates 36 and 37 defining the top and bottom walls of chambers 38 and 39. By virtue of this extensive area contact between the inner ends of legs 45 and 46 and the elements which overlie and underlie them, there is wide dissemination of the forces acting on these parts with resulting decrease in the unit pressure. This is what makes possible the simple construction characterizing pivot pins 41 and 42.

Near the inner ends thereof, legs 45 and 46 are provided with aligned openings (not shown) for receiving a locating pin 51, best shown in Figure 5, and a like locating pins 53 on the opposite side of platform 1. Locating pin 51 consists of a head portion 51a and a shank portion 51b; similarly, locating pin 53 consists of a head portion 53a and a shank portion 53b. Cooperating with locating pins 51 and 53, respectively, are two series of holes 52 and 54 in base plate 11, wherein the holes of each series are disposed in arcuate arrangement as indicated in Figure 1. Pivot pins 41 and 42 are disposed at the centers, i. e., at the ends of the radii, of the arcs defined by the two series of holes 52 and 54, respectively. Like series of holes, shown in Figure 3, are formed in alignment therewith in flanking plates 36 and 37.

If it is desired to retain legs 45 and 46 in the retracted positions shown in full lines in Figures 1 and 3, locating pins 51 and 53 are passed through the outermost holes of each series and the aligned holes in the two legs. if it is desired to spread legs 45 and 46 to straddle relatively wide obstacles, such as the wheels at the front or rear of an automobile, locating pins 51 and 53 may be removed from the holes in which they appear in Figure 1, after which the legs may be angled outwardly as desired and locating pins 1 and 53 reinserted in other holes positioned inwardly thereof in same series. Generally, during such time as the floor crane is in actual use, legs 45 and 46 will be angled to one of the positions represented by dotted line positions 45 and 46' in Figure 3. When it becomes desirable to move the crane from one position to another, legs 45 and 46 may but need not necessarily be retracted to the position shown in full lines in Figures 1 and 3; however, in moving the crane through relatively narrow openings, such as small doorways, it will usually be found necessary to retract legs 45 and 46.

The pin-and-hole means for locating legs 45 and 46 with respect to platform 1 and the longitudinal axis of the crane as a whole thus provide a desirably wide range of positions between extremes represented by retracted and fully spread positions.

The forward ends of legs 45 and 46 may be closed off, if desired, although there is no particular advantage to closing them. They are therefore shown in the drawings as open. However, the opposite or far ends of legs 45 and 46 will ordinarily be closed off by cross plates 55 which are preferably welded thereto as indicated in Figure 5. Ordinarily, cross plates 55 will be considerably larger in area than the transverse cross sections of legs 45 and 46, being both longer and wider. To them is welded a web-like shield 56 that is U-shaped as seen from above. To its top edges is welded a U-shaped cover plate 57. A top gusset 58 and side gussets 59, so shaped as to conform to the needs of the situation, are welded in place as shown to provide rigidity for the rear caster housings provided at ends of legs 45 and 46 by cross plates 55, shields 56 and cover plates 57.

The rear caster assembly in each case consists of a mounting plate 61, which is bolted or otherwise fastened to the lower face of cover plate 57, a free-swiveling caster bracket 62, and a heavy-duty caster wheel 63. The parts forming caster bracket 62 have rigidly associated with them a forwardly projecting extension 64, such extension being tongue-shaped and rather closely underlying cover plate 57. Extension 64 is provided with an opening (not shown) for receiving a locating pin 65 provided with a head portion 65a and a shank portion 65b. In general, locating pin 65 serves the purpose of keeping caster wheel 63 from swiveling when the fioor crane is being moved from one position to another with the legs in retracted position.

When the floor crane as a whole is in such position, as in moving it through a doorway, pin 65 passes through a centrally located opening (not shown) in cover plate 57 and thence into the underlying opening in extension 64, thus holding caster bracket 62 and caster wheel 63 in a position in which they are aligned with the longitudinal axis of the leg with which they are associated. If it is desired to permit the caster assembly to have swiveling movement within the limits permitted by the side walls of U-shaped shield 56, locating pin 65 is withdrawn and reinserted in an extra opening 66. When locating pin 65 is in this position, it does not interfere with extension 64, which is free to move from one side to the other in an arcuate path. Thus caster bracket 62 and caster wheel 63 have a corresponding degree of freedom for swiveling movement within the limits imposed as above explained by the sidewalls of U-shaped shield 56.

Although it is apparent that numerous changes in construction are possible, the above-described arrangement of parts is especially advantageous in that it provides a highly rigid, stable floor crane characterized by an unusually high degree of adjustability and adaptability. In traveling position, i. e., the position in which the legs parallel the boom, the floor crane has adequate lateral stability for all ordinary uses; but by moving the legs outwardly into one of the several alternative positions which the pin-and-hole adjusting means make possible, even greater stability is provided. At the same time, the spread position of the legs permits the crane to straddle and to be used in close proximity to relatively wide objects. By virtue of the built-up nature of the substructure and particularly the extensive area contact between the legs and the platform, the forces imposed on boom, mast and cylinder by the load being lifted are transmitted to and distributed over broad surfaces at the inner ends of the legs, whereby the unit pressures thereon are minimized. A flexible connection between the legs and platform is provided without thereby introducing excessive deflection into any of these parts, this notwithstanding use of the floor crane to lift very heavy objects.

It is intended that the patent shall cover, by summarization in the appended claims, all features of novelty resident in the invention.

What is claimed is:

1. In a floor crane, substructure comprising a substantially flat base plate; a web-like shield depending from the base plate around a large part, but less than all, of the periphery thereof; reinforcing means depending from the base plate interiorly of such peripheral shield; bottom structure paralleling the base plate, such bottom structure extending outwardly from the reinforcing means to the peripheral shield; pivot pins extending between the base plate and the bottom structure toward the rear of the substructure; stabilizing legs pivoted on said pivot pins, said-stabilizing legs extending generally rearwardly beyond the limits of the substructure but projecting inwardly at their inner ends beyond said pivot pins at least far enough to permit of substantial arcuate movement of such inner ends in the space between the reinforcing means and the peripheral shield.

2. In a floor crane, substructure comprising a substantially flat base plate; a plurality of caster assemblies on the base plate; a web-like shield depending from the base plate, such shield extending around the greater part, but less than all, of the periphery thereof; web-like reinforcing means depending from the base plate interiorly of such peripheral shield; bottom structure paralleling the base plate, such bottom structure extending outwardly from the reinforcing means to the peripheral shield; a plurality of stabilizing legs projecting outwardly beyond the peripheral shield, the inner ends of said stabilizing legs being pivotally mounted in the space between the reinforcing means and the peripheral shield; a caster housing at the end of each leg, such caster housing comprising a cross plate, a web-like shield, and a cover plate; and a caster assembly in each of the caster housings.

3. In a floor crane, substructure comprising a flat base plate having a rounded forward portion; two like caster assemblies mounted on the base plate below the forward portion thereof; a web-like shield depending from the base plate, such shield extending around said forward portion and thence rearwardly through the greater part, but less than all, of the periphery of the base plate; weblike reinforcing means of generally triangular configuration depending from the base plate interiorly of such peripheral shield, one of the apices thereof pointing forward; flat bottom structure paralleling the base plate, such bottom structure extending outwardly from the sides of said reinforcing means to the adjacent side portions of the peripheral shield; two pivot pins extending between and supported by the base plate and the bottom structure; two like stabilizing legs mounted on said pivot pins, said stabilizing legs extending generally rearwardly beyond the limits of the substructure but projecting inwardly at their inner ends at least far enough to permit of substantial arcuate movement of such inner ends in the space between the reinforcing means and the peripheral shield; a caster housing at the end of each of the two stabilizing legs, each of said caster housing comprising a transversely extending cross plate, a fiat cover plate, and a depending web-like shield; a caster assembly rotatably mounted in each of the two caster housings; and means on each of the cover plates for optionally permitting or preventing swiveling of the casters.

References Cited in the file of this patent UNITED STATES PATENTS 115,779 Stafiord et a1. June 6, 1871 649,300 Hall et a1. May 8, 1900 1,193,551 Howard Aug. 8, 1916 1,429,216 Arwine Sept. 19, 1922 1,846,567 Murray, Jr. Feb. 23, 1932 2,174,415 Curtis Sept. 26, 1939 2,517,813 Wallace Aug. 8, 1950 2,553,955 Berchtold May 22, 1951 2,613,083 Moludy Oct. 7, 1952

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