US 3419157 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Dec. 31, 1968 R. .1. BRADY 3,419,157
BOOMS HAVING THREE SECTIONS, FULLY EXTENSIBLE WITH AXIALLY CQNNECTED RAMS Sheet Filed April 25. 1967 INVENTOR J. BRADY ATTORNEYS R. J. BRADY Dec. 31, 1968 BOOMS HAVING THR EE SECTIONS, FULLY EXTENSIBL WITH AXIALLY CONNECTED RAMS Filed April 25, 1967 Sheet INVENTOR BRADY RUPERT ATTORNEYS United States Patent 3,419,157 BOGMS HAVING THREE SECTIDNS, FULLY EXTENSIBLE WITH AXIALLY CONNECTED RAMS Rupert J. Brady, 7201 Pyle Road, Bethesda, Md. 20034 Fiied Apr. 25, 1967, Ser. No. 633,510 3 Ciaims. (Cl. 212-55) ABSTRACT OF THE DISCLOSURE An extensible boom, of the telescopic type for cranes, having at least three boom sections connected for extension and retraction by a pair of multiple section hydraulic rams connected in substantially end-to-end relation interior of the boom sections. Both of the rams are supported by a common member connected with the boom mid-section and extending longitudinally thereof whereby the boom fly-section telescopes over said member and said pair of rams, in the retracted position.
A four section version of the boom includes a third double-acting ram connected between two of the boom sections and interior thereof, disposed substantially parallel with the pair of rams, whereby the boom fly-section in the retracted position telescopes over all three rams, thereby providing a four section telescopic boom in which all sections are hydraulically extensible and in which there is only a slight variation in the vertical cross-section dimension between all adjacent boom sections.
Background 0 the invention This invention is an improvement on the invention disclosed in Patents 3,243,052 and 3,315,821 issued to John L. Grove on Mar. 29, 1966, and Apr. 25, 1967, respectively. These patents disclose three and four section extensible booms which are fully hydraulically extensible by individual hydraulic rams positioned in side-by-side relation interior of the boom. In the three section fully hydraulically extensible boom of Patent 3,243,052 the boom sections have a vertical height of a dimension to accommodate a pair of hydraulic ran-rs, one above the other, interior of the boom. It is sometimes desirable to have a fully extensible three section boom in which the heights of the boom sections are less than that required to house a pair of rams one above the other. it is thus the purpose of this invention to provide such a boom structure and still provide the desirable features of all sections being selectively fully hydraulically extensible.
Up to this time four section extensible booms, in which all four sections are selectively fully extensible, have had a considerable difference in the vertical crosssectional dimension between at least a pair of the boom sections, usually between the base section and the inner midsection, because it has been necessary to connect a hydraulic ram between the inner portion of the base section and outer portion of the other boom section, such that the other boom section does not telescope over the ram. In the four section boom of the present invention all of the hydraulic rams are placed interior of all four boom sections so there is only a slight variance in the vertical cross-section dimension between all adjacent boom sections, just enough so they can respectively telescope into each other. Since the vertical dimension or height of the vertical walls of the boom sections is one of the major design factors in the strength or lifting capacity of a boom, since the greater the height of the vertical walls the greater is the resistance to bending forces, this means that a four section boom according to the present inven- Patented Dec. 31, 1968 tion, with a base section of the same wall height as the base section of the before-mentioned prior art boom, will have a substantially greater lifting capacity because the vertical wall heights of the succeeding boom sections are all substantially greater than the wall heights in the corresponding sections of the prior art boom.
These advances are brought about in the present invention by the use of a pair of double-acting multisection telescopic rams connected in substantially axial alignment between three of the boom sections. It is known in the art to connect a pair of hydraulic rams in axial alignment for operating a two section boom but the art does not suggest how such an arrangement can be utilized for providing a three section boom in which all of the sections are selectively hydraulically extensible, as in the present invention.
Summary of the invention The present invention provides an extensible telescopic boom in which two of the sections are extensible from and retractable into the other section. This structure may be used in a three section telescopic boom configuration or in a four section, or greater number of sections, telescopic boom configuration. In the three section extensible boom configuration a mid-section is telescopically disposed in a base section and a fiy-section is telescopically disposed in the mid-section, with the differences in the cross-sections of the respective sections being just enough so that the sections can effectively telescope within each other. A ram support member rigidly connected with the back of the mid-section extends longitudinally interiorly of the mid-section and terminates in a free end at a point adjacent the outer end of the mid-section. A first multisection, double-acting telescopic hydraulic ram is pivotally connected between the inner end of the base section and a point on the ram support member intermediate the ends of said member. A second multisection, double-acting telescopic hydraulic ram is pivotally connected between substantially the same point on the ram support member and the outer end of the fly-section, with this second ram connected in substantially axial alignment with the firstmentioned ram. With this construction the fly-section telescopes over the ram support member and the pair of axially connected multisection rams in the retracted position. Friction means are provided on the free end of the ram support member for commonly supporting the weight of the front portion of the first ram and the rear portion of the second ram on the inner surface of the fiy-section, preferably at a point forwardly of the connection of the two rams to the ram support member.
In the four section configuration of the boom the flysection, outer mid-section and inner mid-section are COnnected in the same manner as in the three section boom. The inner mid-section is disposed to telescope into a base section which has a cross-sectional size just sufficient to receive the inner mid-section. The cross-sectional dimensions of the various sections thus diminish only slightly between adjacent boom sections, from the base section respectively out to the fly-section, thus obtaining the maximum vertical wall height in each boom section. A second ram support member is substantially rigidly connected to the inner end of the inner mid-section and extends longitudinally of the interior thereof with the free terminal end provided with a means disposed in movable friction engagement with the interior surfaces of the fly and outer mid-sections during operation. A single, double-acting hydraulic ram is connected between the rear of the base section and a point on the second ram support member for selectively extending and retracting the inner mid-section and the other boom sections carried thereby, relative to the base section. With this construction, the fiy-section in the retractive position, as well as the outer mid-section and inner mid-section, in the retracted position, telescope over both of said ram support members and the three hydraulic rams. With this construction any bootm section can be selectively extended and retracted from its adjacent section, independently of the other sections.
Brief description of the drawings FIG. 1 is a schematic, vertical, longitudinal sectional view of the three section boom of the invention, the boom shown in the extended position;
FIG. 2 is a schematic view similar to FIG. 1, but showing the boom in retracted position;
FIG. 3 is an enlarged, foreshortened, longitudinal sectional view of the boom of FIG. 2, showing the boom in greater detail;
FIG. 4 is a schematic view showing the four section boom of the invention in retracted position;
FIG. 5 is an enlarged, foreshortened, longitudinal sectional view showing the boom of FIG. 4 in greater detail;
FIG. 6 is an enlarged front elevational view of FIG. 5;
FIG. 7 is an enlarged, cross-sectional view taken substantially along line 77 of FIG. 5 and particularly showing the pivot connection of the pair of rams to the common longitudinally extending support member; and
FIG. 8 is an enlarged rear elevational view of the boom of FIG. 5.
Description of the preferred embodiments Referring first to the three section boom of FIGS. 1, 2 and 3, in greater detail, a rectangular cross-sectional base section 1 is disposed to be pivotally connected at 2 to a boom support and to be pivoted to various elevation angles about point 2 by means of hydraulic ram means, not shown, pivotally connected to the base section at 3. The present drawings disclose the boom in its simplest detail with the reinforcing structure about the pivot points 2 and 3 omitted for sake of clarity, but this structure is substantially the same as shown and described in the two mentioned Grove patents. A substantially rectangular cross-sectioned mid-section 4 is telescopically disposed in base section 1 and a substantially rectangular cross-sectioned fly-section 5 is telescopically disposed in mid-section 4. A boom nose assembly 6 is connected to the end of the fly-section in the normal manner as shown in dotted lines and a hoist cable 7 extends from a winch, not shown, on the crane body, through the upwardly opening cable guide channel 8, along the top of the boom and over the nose assembly for controlling a hook assembly, or the like, not shown, on the end thereof.
The cross-section modulus between adjacent succeeding boom sections varies only by an amount which enables the various sections to effectively telescope into each other. A ram support member 9 is substantially rigidly connected at 10 by means of bracket members to the rear portion of mid-section 4 and extends longitudinally of the interior thereof, terminating in a free end 11 which is supported in movable friction engagement by means of skids 12, or a roller assembly, not shown, with the interior bottom surface of fly-section 5 which is disposed in surrounding relation to, and telescopes over, ram support member 9. Ram support member 9 is preferably of a length such that the skids 12 remain in contact with the inner surface of fly-section 5 in the extended position of the fiy-section as shown in FIG. 1.
Ram support member 9 is substantially an integral part of mid-section 4 and is preferably in the form of a rectangular cross-section housing, but may be in any form such as a rigid angle member, a pair of inwardly-facing channel members or a rod, so long as it is sufficiently rigid to partially support the weight of the pair of ram members, to be described. A pair of double-acting, multiplesection hydraulic rams 13 and 14, of the type well-known in the art, for instance each consisting of three telescopic sections 15, 16 and 17, are connected in substantially axial alignment interior of all of the boom sections. It is to be understood that the rams 13 and 14 may consist of more than three telescopic sections where required, depending upon the length of the boom sections to be extended. Hydraulic fluid is supplied to the double-acting multisection rams by means of hydraulic lines, not shown, in the usual manner, and spring-loaded takeup reel means, not shown, are also provided in the usual manner for taking up and retracting the hydraulic lines as the boom sections are extended and retracted.
One end of hydraulic cylinder 15 of hydraulic ram 13 is pivotally connected at 18 to the inner end of base section 1 and the end of the telescopic rod 17 is pivotally connected at 19 to a shaft assembly 20 supported by ram support member 9, such as by extending transversely between the side walls of the ram support member. The end of cylinder section 15 of hydraulic ram 14 is pivotally connected by a pair of clevis members 21 to shaft assembly 20 On opposite sides of pivot connection 19 such that the cylinder end of ram 15 is supported by ram support member 9. It is to be understood that ram 14 may be connected to support member 9 by a separate shaft assembly 20, but in the preferred form, both rams are connected to ram support member 9 by the same shaft assembly 20. The end of rod section 17 of multisection hydraulic ram 14 is pivotally connected at 22 to the outer end of fly-section 5.
It is to be noted that the multisection hydraulic rams 13 and 14 are disposed in axial alignment within the housing of ram support member 9, in the retracted positions, FIGS. 2 and 3, such that the fly-section telescopes over the ram support member 9 of the mid-section, substantially throughout its length and over the axially aligned hydraulic rams 13 and 14. This construction eliminates stacking of hydraulic rams within a three section boom, and even though a multisection, double-acting hydraulic ram is larger in diameter than a single piston-cylinder double-acting ram, the construction enables the provision of a three section selectively extensible boom, in which the overall vertical wall height of the boom sections is reduced from that required when cylinders are stacked and the construction still provides a boom in which the cross-section modulus of succeeding boom sections varies only slightly.
Part of the weight of both rams is supported by skid 12 which is positioned forwardly of shaft assembly 20 by a sufficient amount so that it always remains in sliding contact with the interior bottom surface of fiy-section 5. By this construction, ram 14 in effect is connected to the inner or rear end of mid-section 4, and the rod end of ram 13, is also effectively connected to the rear end of mid-section 4, but yet their connection point to the midsection is substantially medial of the mid-section.
The tour section version of the telescopic boom of the invention is disclosed in FIGS, 4-8, wherein similar reference numerals refer to like components and primed reference numerals refer to corresponding components disclosed in the three section version of the boom. It is to be understood that the cross-section views of the four section boom also disclose the cross-sectional construction of the three section boom. The four section boom comprises a base section 23, an inner mid-section 1', an outer mid-section 4 and a fly-section 5', all of generally rectangular cross-section and respectively telescoped into each other, such that there is only a slight difference in the cross-section modulus of succeeding boom sections. Bearing pads 24 are connected adjacent the fronts of boom sections 23, 1' and 4 and on the upper rear surfaces of sections 4 and 5 in the usual manner to aid in smooth s1idin operation of the boom sections. A roller assembly 26, connected to the rear of boom section 1' and disposed in rolling engagement with the inner top surface of boom section 23, may be used in lieu of bearing pads throughout the structure. Bearing shim plates 25 are appropriately connected as shown between the various surfaces of adjacent boom sections, in the normal manner to eliminate slack movement between adjacent sections. The bearing shim plates 25 and bearing pads 24 may be constructed of brass or other suitable bearing material. Bearing pads 24 and bearing shim plates 25 are connected in the same manner between the various boom sections of the three section boom as shown in FIG. 3. It is to be understood that the boom sections -1, 4' and 5 are constructed and connected for operation with each other in substantially the same manner as corresponding boom sections 1, 4 and 5 in FIGS. 1-3, with the exception that the heights of the vertical walls of the boom sections are greater in order to accommodate a further hydraulic ram beneath the pair of multisection hydraulic rams 13' and 14. The multisection hydraulic rams 13' and 14 are respectively pivotally connected between inner mid-section 1 and shaft assembly 20 of ram support member 9', and the shaft assembly 20 and fiy-section 5. This pair of multisection rams is housed in ram support member 9' which in turn commonly supports part of the weight of the rams on the inner surface of the fiy-section by the enlarged skids, or roller assemblies, not shown, 12.
A second ram support member 27, of substantially the same configuration as member 9, is substantially rigidly connected by bracket members 28 to the rear of inner mid-section 1, at a position beneath ram support member 9'. Second ram support member 27 extends longitudinally of the interior of the inner mid-section 1, and in retracted position, extends interiorly of sections 4' and 5', and its free end is disposed in movable friction engagement with the interior surface of fly-section 5' and outer mid-section 4' by means of skids 29 or by means of a roller assembly, not shown. A double-acting hydraulic ram 30 is disposed in the second ram support member 27, in retracted position, with the end of its cylinder 31 pivotally connected at 32 to the inner end of base section 23, and the end of its rod 33 pivotally connected at 34 to second ram support member 27 through the shaft assembly 35. The weight of ram 30 and second ram support member 29 is thus partially supported by the skids 29 on the other boom sections and with this construction hydraulic ram 30 in effect is connected to the front portion of inner midsection 1' with no transversely extending connecting pin to block the passage of sections 4 and 5 from telescoping into section 1. Hydraulic ram 30 is disposed substantially parallel with the pair of axially aligned multisection hydraulic rams 13' and 14, and the ram support members 9 and 27 are disposed one above the other and substantially parallel With each other. With this construction for a given vertical wall height of base section 23,
a substantially greater vertical wall height is provided in boom sections 1, 4 and 5', because the construction allows for all three rams to be positioned interiorly of the boom sections so that the fly-section telescopes over all three rams and the two ram support members in the retractible position. In the prior art the vertical wall heights of sections comparable to sections 5, 4 and 1' were considerably less than the vertical wall height of the base section because one of the hydraulic rams was positioned exteriorly of the inner mid-section. The present invention thus makes the outer three sections capable of lifting heavier loads than comparable booms in the prior art as it enables them to provide greater resistance to bending stresses due to the increase in the vertical wall heights of the sections relative to the height of the base section wall.
1. A boom having at least four telescopic extensible sections comprising, a first section, a second section telescopically disposed in said first section, a third section telescopically disposed in said second section, means connected to one end of said second section and extending longitudinally of the interior thereof, said means having a free end in proximity to the outer end of said second section, support means connected to said free end and disposed in movable friction engagement with the inner surface of said third section, a first multisection double-acting hydraulic ram independently pivotally connected to said first section and said means to extend and retract said second section, a second multisection double-acting hydraulic ram independently pivotally connected to said means and said third section to extend and retract said third section, said second multisection ram connected in spaced relation with and in substantial axial alignment with said first multisection ram, and said first and second multisection rams connected to said means in the proximity of the medial portion of said second section, whereby said third section telescopes over said first and second multisection rams and said means in the retracted position of said boom, and said first and second multisection rams are individually supported by said means and said support means, a fourth section telescopically receiving said first section, a second means connected at one end to the corresponding end of said first section and extending longitudinally of the interior thereof substantially parallel with said first mentioned longitudinally extending means, a third hydraulic ram connected to said fourth section and said second means to extend and retract said first section relative to said fourth section, and said third section disposed to telescope over said second and first mentioned longitudinally extending means and said first, second and third rams in the retracted position.
2. A boom as set forth in claim 1 in which said second longitudinally extending means is disposed in the same vertical plane as said first mentioned longitudinally extending means and includes a free end, second support means connected to said free end an ddisposed in movable friction engagement with the interior of said third and second sections as the sections are extended and retracted.
3. A boom as set forth in claim 1 in which said third hydraulic ram comprises a single cylinder-piston doubleacting hydraulic ram positioned beneath said first and second multisection rams.
References Cited UNITED STATES PATENTS 3,243,052 3/1966 Grove 212-444 3,259,251 7/1966 Stauffer 212- 3,353,686 11/1967 Cowan 21255 EDWARD A. SROKA, Primary Examiner. H. C. HORNSBY, Assistant Examiner.