Telescoping Patents (Class 52/118)
  • Patent number: 4201022
    Abstract: A first wheeled trailer means includes support means for supporting a mast and drawworks thereon and a second wheeled trailer means includes an upright structure for supporting the mast in upright positon to conduct well operations. The second trailer means also includes ramp and platform means to receive and position the first trailer means thereon in elevated position whereby the mast may be pivotally engaged with the upright structure of the second trailer means so that thereafter the mast may be raised to an upright position for conducting well operations. The first and second trailer means also include cooperating means to position and secure them together to form a base substructure support for the elevated mast and the drawworks while the well operations are performed.
    Type: Grant
    Filed: September 8, 1978
    Date of Patent: May 6, 1980
    Assignee: Pyramid Manufacturing Company
    Inventor: Gary L. Jennings
  • Patent number: 4185426
    Abstract: A telescoping boom lift apparatus having a first boom mounted about a first substantially fixed horizontal pivot axis in a mobile base for vertically pivotable movement with respect thereto and further having a second boom member carried by, and received in, the first boom member is provided with a link secured between a second substantially fixed horizontal pivot axis on the mobile base and a third horizontal pivot axis on the second boom member whereby, when the first boom is rotated through an increasing included vertical angle, the third pivot axis on the second boom member is moved therewith longitudinally of the first boom member and away from the first horizontal axis thereby reciprocating the second boom member along a portion of the length of the first boom member to cause the distal end of the second boom member to increasingly extend beyond the first boom member.
    Type: Grant
    Filed: January 30, 1978
    Date of Patent: January 29, 1980
    Assignee: A-T-O Inc.
    Inventor: William A. Prescott
  • Patent number: 4171598
    Abstract: A hollow rectangular boom formed with four corner sections of identical cross section and plates interconnecting the corner sections is disclosed herein. Each of the corner sections is identical and is generally L-shaped in cross section with first and second legs each having a recess with adjacent pairs of corner sections being interconnected by flat plates received into the respective recesses and welded therein.
    Type: Grant
    Filed: October 21, 1977
    Date of Patent: October 23, 1979
    Assignee: J. I. Case Company
    Inventor: Terry M. Holmes
  • Patent number: 4171597
    Abstract: A section for a telescopically extensible crane is octagonal in cross-section. The section has relatively thick upper and lower parallel plates, and side members each having a part inclined outwardly for each of the upper and lower plates and a central part generally perpendicular to the upper and lower plates. The central part of each side member may extend over more than half the height of the boom section and the inclined sections may be of differing lengths and thus inclined at different angles to the respective upper and lower plates. Preferably, the lower inclined sections are shorter than the upper inclined sections. The boom section may be reinforced by external belts, or by internal support plates.
    Type: Grant
    Filed: June 7, 1978
    Date of Patent: October 23, 1979
    Assignee: Coles Cranes Limited
    Inventors: Robert J. Lester, William Jack
  • Patent number: 4169338
    Abstract: A telescopic boom includes three or more sections which may be pivoted if desired. The innermost section is incapable of moving in the longitudinal direction, whereas the other sections are adapted to be concurrently dislocated in the longitudinal direction relative to each other. Only a drive mechanism on the innermost section is adapted to be actuated from an outside source, whereas the other sections are driven by the relative motion of the sections movable in the longitudinal direction.
    Type: Grant
    Filed: August 29, 1977
    Date of Patent: October 2, 1979
    Assignee: A/S NorMar
    Inventor: Geir Eik
  • Patent number: 4168008
    Abstract: A large light-weight telescopic crane boom comprises a plurality of relatively movable boom sections, such as base, intermediate, outer, and fly sections, and each section comprises top and bottom walls and a pair of spaced apart side walls. In each pair of relatively movable adjacent boom sections wherein one (inner) section is telescopically receivable within another (outer) section, the inner surface of the side walls of the outer section and the outer surface of the side walls of the inner section comprise longitudinally extending corrugations or projections which interengage and whereby the inner section is slideably supported on the outer section. The corrugations or projections on each wall surface are arranged in two (upper and lower) sets, one above and the other below, the longitudinal neutral axis of the crane boom.
    Type: Grant
    Filed: February 23, 1978
    Date of Patent: September 18, 1979
    Inventor: Tod G. Granryd
  • Patent number: 4166542
    Abstract: A lattice boom crane is provided with multiple boom sections which telescope one from the other to provide a variable length boom. A cable system is connected between the boom sections such that the boom sections are telescoped as the cable is drawn in by a winch mechanism. Cables drawn in by the winch mechanism is directed to a block system which is connected between a gantry structure and the point end of the outermost boom section. The winch mechanism includes two drums about which the cable is alternately wrapped. The block system expands at substantially the same rate as the boom sections extend. Thus, the boom angle, which is determined by the effective cable length between the gantry and the point of the boom, is not significantly effected. In one embodiment of the invention, the cable taken in by the block system is received on a boom hoisting drum which may be controlled to change the effective cable length between the gantry and the point of the boom to vary the boom angle.
    Type: Grant
    Filed: December 5, 1977
    Date of Patent: September 4, 1979
    Inventor: John F. Bryan, Jr.
  • Patent number: 4156331
    Abstract: A multi-section telescopic jib or boom comprising a base section and three movable sections mounted to extend or retract relative to each other on operation of drive means within the sections, including a first ram connected between the base section and the innermost sections, a second ram connected between the innermost and central sections and a chain having ends connected between the innermost section or the first ram and engaging a chain wheel mounted on the central section or second ram, means being provided to releasably connect the chain to the outermost section to extend the boom.
    Type: Grant
    Filed: November 10, 1977
    Date of Patent: May 29, 1979
    Assignee: Coles Cranes Ltd.
    Inventors: Robert J. Lester, Raymond Murta
  • Patent number: 4138805
    Abstract: A first and second mobile trailer means are secured together for forming a base substructure support for a mast, setback tower and drawworks. A working floor is provided in elevated position above the base substructure support when the mast, setback tower and drawworks is in position to conduct well operations. The telescoping mast and setback structure is pivotally carried on the first trailer means and a drawworks is pivotally carried by the second trailer means. A power and rig up arrangement is provided to elevate in a desired sequence the mast, setback structure and drawworks to a desired position for securing on the base substructure support formed by the first and second trailer means for conducting well operations.
    Type: Grant
    Filed: October 17, 1977
    Date of Patent: February 13, 1979
    Assignee: Pyramid Manufacturing Company
    Inventor: Bradley C. Patterson
  • Patent number: 4137535
    Abstract: The present antenna mast is constructed to telescope in response to pneumatic pressure. For this purpose a bottom tubular section has a pressure inlet and each further tubular section has a lower end fitting as a piston into the next lower section. Each piston has a passage for a gas under pressure into the next higher section. The upper end of the uppermost section is closed. The antenna is retracted by venting the bottom tubular section.
    Type: Grant
    Filed: September 9, 1977
    Date of Patent: January 30, 1979
    Inventor: Walter Rupprecht
  • Patent number: 4134237
    Abstract: A multiple section mast having telescoping modular sections adapted to be erected at remote land sites or on offshore platforms by small capacity cranes. A separate lower mast section having an open side is first placed in vertical position on a substructure. A separate upper mast section is moved horizontally into the lower mast section then elevated vertically to extend above the lower mast section. A separate intermediate mast section having at least part of one side open is then moved horizontally into the lower mast section and fastened to the lower end of the upper mast section. The upper and intermediate mast sections are then simultaneously elevated until the lower end of the intermediate mast section can be fastened to the upper end of the lower mast section. Retainer means removably attached to the lower mast section extend into the open side engaging the upper and intermediate sections as they are telescoped.
    Type: Grant
    Filed: July 18, 1977
    Date of Patent: January 16, 1979
    Assignee: Pool Company
    Inventor: James E. Armstrong
  • Patent number: 4134236
    Abstract: Adjustable side shoe assemblies are provided on respective side walls of adjacent movable boom sections of a crane boom assembly to maintain alignment between the sections. A boss provided on each side wall at the upper end of a movable boom section of a crane boom assembly has a tapped hole passing through the section. A threadable member, preferably composed of a phenolic or other abradable material can be inserted into the threaded opening provided in the side wall of the boom section, the member being threadably rotated into the opening to engage the side wall of the next adjacent boom section. Respective aligned openings provided in the side walls of the boss and the threadable member receive a retaining member, such as a cotter pin, to hold the threadable member in place on the boom section.
    Type: Grant
    Filed: November 26, 1976
    Date of Patent: January 16, 1979
    Assignee: Clark Equipment Company
    Inventor: Edward R. Ott
  • Patent number: 4133411
    Abstract: An extension and retraction mechanism for a three section extensible boom is disclosed utilizing an internally disposed hydraulic cylinder connected between a stationary boom section and an intermediate boom section with a cable connection located entirely interior of the boom having opposite ends anchored to opposite ends of the stationary section with the cable routed around sheaves on the moving end of the hydraulic cylinder and a base end of the intermediate boom section with a cable attachment to the base end of the inner boom section, the inner boom section being the most extensible boom section.
    Type: Grant
    Filed: February 11, 1977
    Date of Patent: January 9, 1979
    Assignee: Chamberlain Manufacturing Corporation
    Inventor: Walter R. Curb
  • Patent number: 4132041
    Abstract: A telescopic boom assembly including first and second telescoping members. The assembly employs rack and pinion telescoping mechanisms which are driven by hydraulically controlled piston and cylinder members. The combination provides positive and precise positioning of the telescoping members and extremely smooth movement thereof.
    Type: Grant
    Filed: October 27, 1977
    Date of Patent: January 2, 1979
    Inventor: Bernardus C. Van den Broek
  • Patent number: 4118907
    Abstract: Mobile lifting equipment having a wheeled vehicle with a frame. The boom structure is mounted on the frame for rotation about a vertical axis, raising and lowering the same about a horizontal axis and for extension and retraction with respect to the vehicle. The boom structure includes an outer boom and an inner boom which is mounted for telescoping movement in the outer boom. First and second extension cylinders are carried by the outer boom for extending and retracting inner boom with respect to the outer boom. An elevation cylinder is connected to the outer boom and is provided for raising and lowering of the boom structure. An elevation control is provided for supplying hydraulic fluid to the elevation cylinder. Piping is provided for connecting the elevation cylinder to one of the first and second extension cylinders so that extension of said one of said first and second extension cylinders is limited by the amount of hydraulic fluid which has been supplied from the elevation cylinder.
    Type: Grant
    Filed: October 27, 1977
    Date of Patent: October 10, 1978
    Assignee: General Cable Corporation
    Inventors: Robert F. Small, Joel B. Meredith
  • Patent number: 4112649
    Abstract: A large light-weight deflection-resistant telescopic boom section of hollow rectangular cross-section comprises spaced apart top and bottom plates and spaced apart vertical side plates welded therebetween inwardly of the side edges thereof. Longitudinal corner stiffeners of angular cross-section are welded between the outwardly extending portion of the top and bottom plates and the associated vertical side plate to shorten the effective height of the side plate, to stiffen the top and bottom plates, to increase the mechanical section properties, and to provide a flat built-in slide pad bearing surface. Vertical side stiffeners of U-shaped cross-section are welded to the vertical side plates at intervals therealong and to the longitudinal corner stiffeners to provide the buckling resistance and increased shear load capacity of side plates.
    Type: Grant
    Filed: August 26, 1977
    Date of Patent: September 12, 1978
    Assignee: Harnischfeger Corporation
    Inventors: Robert A. Fritsch, Narahari Gattu, Lembit Vaerk
  • Patent number: 4100707
    Abstract: A telescopic boom, for portable cranes, having one or more hydraulically operated telescopic slides, and one or more mechanically operated telescopic slides. The extension or retraction of the mechanically operated telescopic slide is effected by means of a detachable retaining rod, one end of which is connected with the non-telescopic main boom by means of a bolt inserted transversely therethrough. The other free end of the retaining rod is provided with a pressure piece, for maintaining the boom in some of its positions during extension thereof, and a tensioning device, which is located 180.degree. opposite from the pressure piece, for maintaining the boom in some of its positions during retraction thereof. A plurality of slots are arranged along the mechanically operated telescopic slide transverse to the direction of operation. These slots respectively cooperate with a cam of the pressure piece or with a stop cam of a pawl during extension and retraction of the telescopic slide.
    Type: Grant
    Filed: August 24, 1977
    Date of Patent: July 18, 1978
    Assignee: O & K Orenstein & Koppel Aktiengesellschaft
    Inventors: Wilhelm Kranefeld, Helmut Schneider
  • Patent number: 4057942
    Abstract: A telescopic boom for movable cranes with at least one hydraulically operable telescopic slide and with at least one mechanically operable telescopic slide. The pushing out movement and the retracting movement of the mechanically actuated telescopic slide is effected by means of a holding bar having a free end portion provided with a pressing or pushing member and with a pulling member offset by 180.degree. with regard to the pressing or pushing member. The other end of the holding bar is provided with a transverse bolt for engagement with a bearing on the at least one hydraulically operable slide. The mechanically operable telescopic slide is provided with cams extending transverse to its longitudinal direction of movement for cooperation with the holding bar.
    Type: Grant
    Filed: May 3, 1976
    Date of Patent: November 15, 1977
    Assignee: O & K Orenstein & Koppel Aktiengesellschaft
    Inventors: Wilhelm Kranefeld, Helmut Schneider
  • Patent number: 4045936
    Abstract: A multi-section telescopic boom has sections with reinforced I-beam side walls and top and bottom walls made up of truss members. The trusses and beam stiffeners are disposed interiorly of the beam flanges so that the flanges provide continuous upper, lower and side bearing surfaces engageable with wear pads all of which are on the next outermost section. The lower and side wear pads are elastomer backed and the side pads have backup buttons that can easily be shimmed out to compensate for wear.
    Type: Grant
    Filed: April 26, 1976
    Date of Patent: September 6, 1977
    Assignee: Bucyrus-Erie Company
    Inventor: Russell L. Sterner
  • Patent number: 4045923
    Abstract: A telescopic extension jib for crane booms increases the reach of the boom and therefore increases the utility of the construction crane. To facilitate manual extension and retraction of the movable jib section relative to the fixed base section, a system of rollers is employed between the relatively movable jib sections. In the socketing area of the jib at full jib extension, upper and lower rollers are spring-mounted and can bear the dead weight of the movable jib section when the same is unloaded. Coacting bearing pads engage the top and bottom faces of the movable jib section under loading to distribute stresses over larger areas, the spring-mounted rollers retracting automatically to enable the movable jib section to engage the bearing pads in the socketing area. A locating pin is provided to lock the jib sections against accidental relative movement in both the extended and retracted positions of the jib.
    Type: Grant
    Filed: May 6, 1976
    Date of Patent: September 6, 1977
    Assignee: Walter Kidde & Company, Inc.
    Inventor: Venkatachalam Shanmugasundaram
  • Patent number: 4038794
    Abstract: An improved boom section has top and bottom walls formed of sloping plate sections or flanges which define peaks between the side walls. The peaked configuration of the bottom wall increases the buckling strength of the bottom wall over the bucking strength obtained with a flat bottom wall. The sloping flanges of the top and bottom walls are disposed at acute angles of between 12.degree. and 19.degree. to horizontal planes. If the slope of the flanges is increased to an angle significantly greater than 19.degree., the peaks in the top and bottom walls would be disposed relatively far from the central axis of the boom section and would be subjected to excessive stresses upon loading of the boom section. The boom section is advantageously formed with a height-to-width ratio which is greater than 1 and less than 3.
    Type: Grant
    Filed: October 28, 1975
    Date of Patent: August 2, 1977
    Assignee: The Warner & Swasey Company
    Inventor: Warren C. Young
  • Patent number: 4036372
    Abstract: Means for extending and retracting the telescoping boom assembly of a rotatable mobile crane wherein the boom assembly comprises a plurality of telescoping parts, slidably received one into the other. The boom extension and retraction means is operable at any angular displacement of the boom assembly, the operating angle of the boom assembly being maintained during the extension or retraction thereof. Means for extending and retracting the boom assembly include a single fluid driven linear motor or hydraulic cylinder suitably attached at one end portion of the motor to a base portion of the boom assembly. An opposite end portion of the linear motor is selectively securable to the telescoping sections of the boom assembly to permit extension thereof. A cylinder guide is mounted on the fluid driven linear motor, both the cylinder guide and motor contained within the boom assembly, the cylinder guide providing support for the linear motor and maintaining the alignment of the extension and retraction means.
    Type: Grant
    Filed: December 15, 1975
    Date of Patent: July 19, 1977
    Assignee: Clark Equipment Company
    Inventors: Kamlaker P. Rao, William L. Lowe, O. Thomas Nephew
  • Patent number: 4027802
    Abstract: The building panel positioner permits a building board or panel to be positioned adjacent a ceiling or wall framework in building construction. The device comprises a base from which a bottom, intermediate and top section vertically extend in telescoping interfitted adjustably extending relation to each other with support means having a planar surface for support of the board or panel. The support means has retaining means associated therewith to prevent lateral movement with respect thereto. In addition, the retaining means has locking means associated therewith to prevent outward movement of the board or panel relative to the planar surface.
    Type: Grant
    Filed: August 3, 1976
    Date of Patent: June 7, 1977
    Inventor: Francis E. Reynolds
  • Patent number: 4021978
    Abstract: There is disclosed herein a telescoping mast assembly adapted for use with drill rigs and the like. The mast assembly comprises multiple sections, said sections being adapted for nesting one within the other in the telescoped-to-the-closed condition and each section comprising mutually convergent corner leg members which, when said mast assembly is extended, form concentric and in-line arrangements of the corner leg members from the base to the crown of the mast. Means are provided for connecting each mast section to its neighboring mast section upon extension thereof. In addition, means are also provided for indexing of the connector means upon extension of the mast assembly from its telescoped-to-the-closed condition.
    Type: Grant
    Filed: February 25, 1976
    Date of Patent: May 10, 1977
    Assignee: Cabot Corporation
    Inventors: Ralph Busse, Hermus C. Moore, Jr., Raymond L. Welch
  • Patent number: 4016688
    Abstract: An extensible cantilever boom assembly, for a mobile crane, has telescopically interfitting box-like boom sections, that include web or side plates of uniform thickness. These plates are shaped to provide increased stiffness, and openings are provided within some of the plates to reduce the plate weight, so that the load carrying capacity of the boom is increased. A plurality of shaped portions are formed within the plates, at locations intermediate the top edges and the bottom edges of the plates. These plate portions are spaced laterally from the parallel planes that define the side surfaces of the plates, at the junctures of the side surfaces with the top and bottom edges. The shaped portions, located at longitudinally spaced intervals, are aligned in a row that extends longitudinally of the plate. Each shaped portion has a regular geometrical pattern that forms a laterally projecting protuberance on one side of the plate and a corresponding depression on the opposite side of the plate.
    Type: Grant
    Filed: May 27, 1975
    Date of Patent: April 12, 1977
    Assignee: FMC Corporation
    Inventors: Joseph B. Tiffin, Daniel G. Quinn, Evart J. Vroonland
  • Patent number: 4016687
    Abstract: The mast of a portable earth drilling rig is mounted for pivotal movement between a horizontal transport position and selected drilling positions. A series of radially spaced apart lateral projections on each side of the lower end of the mast are provided with apertures for engaging laterally extending projections disposed on a pair of telescopic braces mounted on the rig frame. The braces may be selectively positioned for automatic engagement with a predetermined pair of projections on the mast whereby the mast, for drilling, may be positioned in the desired angular attitude.
    Type: Grant
    Filed: November 13, 1975
    Date of Patent: April 12, 1977
    Assignee: Gardner-Denver Company
    Inventors: T. W. Griffith, Arthur T. Taylor
  • Patent number: 4004695
    Abstract: A telescopic crane boom is provided in which tubular boom sections include a thicker, flat bottom plate and a thinner channel having the free edges of its walls welded to the bottom plate at the lateral edges of the bottom plate. Wear pads for supporting an outer boom section, e.g., the fly section, are placed on the bottom plate of the adjacent inner section, e.g., the mid-section, closely adjacent to the vertical walls of the inner section, and underlying the walls of the outer section, to provide substantially columnar support for the walls of the outer section, reduced bottom plate bending forces, and reduced boom width and weight.
    Type: Grant
    Filed: April 16, 1975
    Date of Patent: January 25, 1977
    Assignee: Fulton Industries, Inc.
    Inventors: John L. Hockensmith, John L. Grove
  • Patent number: 4003168
    Abstract: To reduce the weight of a construction crane boom without materially lessening the lifting capacity thereof where the boom sections have an inverted trapezoidal cross sectional shape, a series of openings is formed in the two side plates of each boom section and such openings are provided with internal reinforcing rings or braces. The bottoms of the reinforcing rings are arranged in stress-transferring relation to the boom section side plates and adjacent longitudinal vertical reinforcing plates or stiffeners provided in the structure. Cooperating side plate brace bars arranged between the reinforced side plate openings have their lower ends attached to the longitudinal side plate stiffeners.
    Type: Grant
    Filed: June 27, 1975
    Date of Patent: January 18, 1977
    Assignee: Walter Kidde & Company, Inc.
    Inventor: Rupert J. Brady
  • Patent number: 3987594
    Abstract: A system and method are disclosed whereby a crane boom assembly of relatively long length and large load carrying capacity may be automatically stowed and carried on the superstructure of a crane assembly. With the boom assembly in the stowed position, the boom and superstructure combination may be carried on a single truck and trailer combination for highway transport. Power driven means are provided for unstowing and stowing the boom assembly with respect to the superstructure. To unstow the boom assembly, first power driven means are provided to translate the boom forwardly with respect to the superstructure. Foot pins located at the rear of the boom assembly are mountable in the main pivot means on the superstructure of the crane when the boom assembly is fully extended forwardly of the superstructure to an intermediate unstowed position.
    Type: Grant
    Filed: February 6, 1975
    Date of Patent: October 26, 1976
    Assignee: Clark Equipment Company
    Inventors: Kamlaker P. Rao, William L. Lowe, O. Thomas Nephew
  • Patent number: 3985234
    Abstract: A telescopic boom of a crane comprising a base element adapted for support on a turret of the crane, and a plurality of telescopic elements slidably engaged within one another and within the base element. The elements have a polygonal cross-section, each element having a lower or inner compression leg of inverted V-shape which opens downwardly and falls the load. First guide shoes are mounted on each telescopic element on the upper or outer leg thereof, bearing against the surrounding element, and second guide shoes are mounted on each branch of the inverted V-shaped inner leg also bearing against the surrounding element.
    Type: Grant
    Filed: December 16, 1974
    Date of Patent: October 12, 1976
    Assignee: Creusot-Loire
    Inventor: Maurice Jouffray
  • Patent number: 3979873
    Abstract: A plurality of telescopic triangular cross sectioned booms slide within one another so that they can be extended and retracted and they are adapted to support conduits for pumping concrete or other material from one location to another. Angulated flanged corner constructions support the booms for sliding movement one with the other and in one embodiment, wheeled trolleys or bogeys are secured to the corners to reduce the frictional load between adjacent boom sections.
    Type: Grant
    Filed: November 22, 1974
    Date of Patent: September 14, 1976
    Assignee: Mancole Company Limited
    Inventor: Manson Ivor Coles
  • Patent number: 3958377
    Abstract: An articulated boom of high strength to weight ratio is disclosed including an inner steel boom of modified trapezoidal cross-section including a top web, inclined opposed side webs and an arcuately curved bottom web; a pivotal elbow connector is mounted on the outer end of the inner boom and supports the inner end of a tapered hollow fiberglass shell defining an outer boom member of inverted modified trapezoidal cross-section including a top wall having progressively decreasing width from its inner to its outer end, opposed side walls which progress inward from top to bottom with the degree of inward taper decreasing from the inner end to the outer end of the outer boom and with the lower ends of the side walls being connected by an arcuate, downwardly convex hollow connector wall opposite the top wall.
    Type: Grant
    Filed: February 21, 1975
    Date of Patent: May 25, 1976
    Inventor: Edwin Earl Milner, Jr.
  • Patent number: 3952466
    Abstract: A means to maintain the upper wear pads in a multisection telescopic crane boom in contact with the side plates of the circumscribing boom section to reduce the transverse bending moment on the top plate of the boom section, thus reducing the stress thereon, and allowing the use of a thinner top plate so as to provide a lighter and less costly boom structure.
    Type: Grant
    Filed: August 8, 1974
    Date of Patent: April 27, 1976
    Assignee: Walter Kidde & Company, Inc.
    Inventor: Stanley R. Spain
  • Patent number: 3942593
    Abstract: There is disclosed herein a mobile well drilling rig apparatus adapted for rapid assembly and disassembly thereof. The drilling rigs of the invention comprise a trailerable telescoping mast assembly and a separate sectionable substructure assembly therefor comprising a rig base, a working floor mounted in spaced relation above the base and a rig base extension extending outwardly from the drawworks side of the rig base. In a preferred embodiment, rail means defining a mastway are provided between the erected working floor and the rig base extension. The base mast section of the telescoping mast assembly is provided with cooperative mast roller means whereby the base of the mast structure is readily conveyed to the working floor and whereby the drawworks side mast legs are engaged into a trunnion arrangement therefor. Means are also provided for raising of the mast structure to the vertical from the drawworks side of the rig.
    Type: Grant
    Filed: October 17, 1973
    Date of Patent: March 9, 1976
    Assignee: Cabot Corporation
    Inventors: John R. Reeve, Jr., Ralph Busse, Elbert Walker, Raymond L. Welch, Hermus C. Moore, Jr., Milton P. Jones
  • Patent number: 3931698
    Abstract: An improved crane boom structure for telescopic boom sections. The conventional, generally rectangular cross-sectional shape is modified to provide central guiding of the boom sections to locate the bearing forces transmitted between sections at or near the neutral axis where bending stresses are minimal for greater load carrying capacity for a given boom weight. The boom side walls are provided with channel shaped projections, the top and bottom channel legs being located on either side of the neutral axis of the beam section, preferably symmetrical therewith. Bearing surfaces are interposed between top and bottom channel legs of contiguous boom sections.
    Type: Grant
    Filed: November 20, 1974
    Date of Patent: January 13, 1976
    Assignee: The Warner & Swasey Company
    Inventor: Robert C. Ebersold