Abstract: A telescopic boom for use on an elevating apparatus includes a first boom, a second boom telescopically disposed in the first boom, a third boom telescopically disposed in the second boom, a rolling mechanism disposed between the first and third booms and rollingly movably on wall surfaces of the first and third booms, and a locking lever assembly disposed on each of ends of the second and third booms in the first boom for selectively engaging the rolling mechanism to connect the rolling mechanism to one of the second and third booms at a time.

Abstract: A device for providing relative movement between three telescopically co-ordinated parts (1, 2, 3) which comprises a power device (7) of a type variable in length and acting between a point (8) on a first (1) and a point (9) on a second (2) of the parts, and a flexible traction element (12), which is arranged to cause relative movement between the third part (3) and the first and said second parts (1, 2) by transmitting forces between the first and the third parts when relative movement between the first and second parts (1, 2) is effected by the power device. The power device located externally of the parts is designed with a longitudinal internal passage (13), in which the traction element extends in its extension between a point (14) on the third part and a point (15) fixed in relation to the first part (1), whereby the power device will operate as a casing variable in length for the traction element.

Abstract: A hanger assembly for one-handed mounting between opposing surfaces of wall studs or ceiling joists in normally inaccessible places. The hanger assembly has telescoping elements with toothed ends which are adapted to pierce into wall studs or ceiling joints when the elements are extended. The telescoping elements are spread apart by planting starter teeth on the follower element into a stud or joist and then turning a main body element until the end teeth of the follower element and the end teeth of the main body unit are fully embedded. The follower element is preferably spring loaded so as to provide the hanger assembly with a following or self-adjusting action. The self-adjusting action causes the hanger assembly to adapt to deformations of the wall studs or ceiling joists and to retain the compressive attachment integrity of the hanger assembly.

Abstract: A powerful, highly maneuverable, man-lifting crane has three vertically articulating sections which swivel on a common turret for horizontal positioning, the third or outer section of the group comprising three telescoping, tubular booms wherein the outermost boom is constructed of a dielectric material such as fiberglass for carrying an electrically insulated man-lifting bucket at its outer end. A pair of hydraulic extension and retraction cylinders for the telescoping booms of the third section are both housed internally of the section and are mechanically interconnected and hydraulically coupled in such a way that, upon extension of the third section, the fiberglass boom always extends first and, upon retraction of the third section, the fiberglass boom always retracts last.

Abstract: A telescopic boom assembly is disclosed. The assembly includes a plurality of boom members having at least first, second and third boom arms telescopically disposed within each other. The first boom arm is connected to a support base. A mechanism is provided for axially extending the second and third boom arms outwardly from the first boom arm, the third boom arm being constructed from dielectric material and disposed at the distal end of the assembly once the assembly is in a fully extended position. Finally, an end cylinder structure constructed from dielectric material is provided for axially moving the third boom arm relative to the first and second boom arms such that the third boom arm and the end cylinder structure dielectrically insulate the distal end of the third boom arm from the remainder of the boom assembly when the assembly is in an extended condition.

Abstract: A locking assembly (35) for telescoping masts (10) having at least first and second tubes (12,13), the second tube (13) fitting within the first tube (12). The assembly includes sleeve means (36) encompassing one end (59) of the second tube (13) and rigidly affixed thereto, cap means (58) affixed to the second tube (13) below the sleeve means (36) forming an air tight seal within the first tube (12), stop ring means (38) carried above the sleeve means (36) and encompassing the second tube (13), recess means (68) formed by the sleeve means (36) and the stop ring means (38) and locking collar means (20) rigidly affixed to a first end (43) of the first tube (12) providing at least one movable member (76) engageable with the recess means (68).

Abstract: A pedestal scaffold type having a base member, a telescopic mast mounted vertically on the base member and a work cage mounted in cantilever manner from the upper end of the mast. The majority of the nested tubular mast sections are of rectangular cross-section and are formed of thin-walled sheet aluminum with rounded corners and vertical stiffening ribs on each side thereof extending the height thereof. Plastic slide blocks at the inner corners of the upper end and at the outer corners of the lower end of the mast section distribute the forces between the sections to relatively large areas of the aluminum sheet which forms the mast sections.

Abstract: A power actuator on the base section of a multi-section telescoping crane boom can bridge at least one intermediate boom section to operate a biased locking pin retract mechanism employed in a system for remotely controlling the operation of a manual fly section of the telescoping boom. To enable the crane operator to know with certainty that the biased locking pin is in a fully engaged position, a visual indicator on the boom readily viewable from the crane operator's cab is directly mechanically linked to the biased locking pin and moves to the indicating position only when the locking pin is fully engaged.

Abstract: A silo mover apparatus comprising a main frame that is movable across the ground on a plurality of support wheels, and which has a subframe pivotallymounted thereon adjacent one end. The subframe can be raised about the pivot to a substantially vertical position through the use of hydraulic cylinders, stabilized in position adjacent to a silo to be moved, clamped to the silo by straps, after the silo has been suitably reinforced, and then the silo can be lifted and tilted downwardly with the subframe to rest on the main frame for transport to a new location. At the new location the silo is then raised by raising the subframe about its pivot, to place the silo onto the desired platform, after which the members that clamp the silo and subframe together are removed.

Abstract: Apparatus for lifting electric line poles is disclosed which also enables a ground rod or stake to be driven into the ground next to such a pole. There is provided a telescopic mast having a hoist with a rope run over pulleys to a lifting hook and attached at the upper end of the mast. For driving in ground rods or stakes a carriage mounted for movement along the mast is used which can be attached to the lifting hook and can secure an air hammer.

Abstract: An extendible structure that can be collapsed to a shorter length and extended to a longer length. A pair of station members are interconnected by at least three longeron members. Each longeron member has two longeron elements that are pivoted together so they can fold toward one another or aligned to form a column. Each element is pivoted to a respective station member. Stays rigidify the structure when extended, and are opposed by buckling springs (Euler columns) that exert an outward resultant force on each longeron member at its folding point.

Abstract: Method and apparatus for raising and lowering a telescoping mast. A telescoping mast having an upper section slidably received within a lower section is pivotally connected to a base in a horizontal position. A line is connected to the lower end of the upper section and is placed over a pulley mounted on the upper end of the lower section and secured to the base. Upward pivoting of the lower section moves the mast to a vertical position while the upper section is extended by action of the line. Lowering the mast from the vertical position causes contraction of the upper section into the lower section.

Abstract: A telescoping mast assembly for floodlighting equipment or other apparatus is arranged to be raised by admitting pressurized fluid to the interior of the assembly and lowered by releasing the fluid. The assembly is constructed of light metal, such as aluminum alloy, and includes a plurality of telescoping hollow members, or tubes, each inner member having a pair of substantially spaced wear rings near its lower end for maintaining the spaced positions of the members and a fitting at its outer end carrying an internally mounted wear ring for maintaining the spacing at the outer end. The telescoping members do not engage one another but are spaced by the wear rings. The fitting is readily detachable and facilitates the use of straight lengths of standard aluminum tube stock for the mast sections. The fittings include keys slidably engaging longitudinal slots in the members for preventing rotation of the members with respect to one another. Seals are provided for preventing leakage of fluid between the members.

Abstract: An extension and retraction system for a multiple section, telescoping boom apparatus of the type utilized for raising and lowering a work platform or basket. The innermost longitudinally movable section is carried by a longitudinally inextensible or base section, and is extensible and retractable relative to the base section by a dual cylinder assembly. Extension chains trained about sprockets carried by certain of the sections automatically extend the other extensible sections upon extension by the cylinder assembly of the innermost longitudinally movable section. Automatic and positive retraction of such sections is accomplished by retraction chains operating in response to retraction of the innermost section. The cylinders of the dual cylinder assembly are pivotally coupled at a pivot mount longitudinally slidable along a guideway carried by the base section to thereby accommodate deflections of the boom sections located between the opposite extremities of the dual cylinder assembly.

Abstract: A mast-type, three-dimensional framework structure of rectangular cross sion with four diagonally-braced frames which form the sides of the framework structure and all of which are manufactured from tubes and tubular joints made from fibre-reinforced plastics. The diagonally-braced frames are so interconnected by means of hinged connections on their longitudinal members that they can be folded flat in such a way that two adjacent diagonally-braced frames lie in each case on top of the two opposite diagonally-braced frames. Between the longitudinal members of two opposite corners of the framework structure, fixed-length cables are fitted which, when the structure is unfolded, form a stay in one of the diagonals. Between the outer opposite corners, which are on the outside when the structure is folded, there are low-friction cable deflectors for a tensioning cable.

Abstract: A telescoping support apparatus for supporting at least one refuse container, the support apparatus comprising a ground cylinder disposable in the ground and having an upper end portion extendible a selected distance above the surface of the ground; a support cylinder supported by the ground cylinder and slidably movable between a retracted position within the ground cylinder and an extended position substantially above the surface of the ground, the support cylinder having an upper portion and a lower portion, the upper portion having an outside diameter less than the outside diameter of the lower portion so that a support shoulder is formed at the junction of the upper and lower portions, the lower portion having a first detent slot formed therein; first stop means supported within the lower portion of the support cylinder for selectively locking the support cylinder in the extended position, the first stop means pivotally supported in the lower portion of the support cylinder so that an end portion of the

Abstract: A multi-section telescopic boom is disclosed having a base section supported for pivotal movement, a manual section telescopically received in said base section, a mid section, and a tip section which sections are progressively lighter from the base section to the tip section when excluding the weight of head machinery connected to the tip section. The heavy manual section is stored in the base section when a load to be transferred between two locations can be reached with the mid and tip sections extended thereby substantially decreasing the turning moment about the pivot axis due to the weight of the boom sections resulting in an increased load carrying capacity of the boom. The boom is preferably supported by a pendant line operatively connected to the outer end of the tip and base sections and trained within the boom to aid a single hydraulic ram to extend and retract selected sections of the boom.

Abstract: A retractable apparatus for holding garbage or refuse cans in an erect position includes a hollow casing implanted in the ground, a telescoping support column contained in the casing, and a head fixture attached to the support column for receiving and securing blade extensions attached to refuse cans. The casing is buried so that its upper end is substantially flush with ground level. The support column is retracted, when not in use, to a storage position contained within the hollow casing, by collapsing a number of telescopically interconnected elements which make up the support column. A recess is provided at the top of the inner surface of the hollow casing to receive and contain the head fixture in a position substantially flush with ground level. To secure refuse cans in an upright position, the support column is telescopically extended to an above-ground position. Blade extensions attached to the refuse cans are then inserted into receiving slots in the now-elevated head fixture.

Abstract: A method and apparatus is disclosed for controlling the angle of a pivoted, pendant supported extensible boom and the mast-boom angle between working positions and a transport position. The structure for controlling the angle includes a wire rope driven by a winch and trained over a boom supporting hoist and over a pendant take-up hoist which includes a floating sheave assembly connected to an extensible portion of the boom by a fixed length pendant. Another fixed length pendant determines the mast-boom angle when the boom is in working position, and a floating sheave stop is pivoted to the mast in position to cradle and/or abut a portion of the floating sheave assembly for enabling complete control of the mast when moved between its transport position and working positions relative to the boom.

Abstract: A latching system is disclosed for a telescopic boom, and comprises a ladder structure for positionment longitudinally along a side of a smaller boom section, and a latch plate assembly for a pivotal attachment to a large boom section. Bias means is further provided for applying a biasing force tending to move the latch plate into the ladder detent slot, and counter bias means for applying counter bias force to the latch plate. Linkages are adapted to extend between the latch plate and the tensioned chains which actuate the small boom section outward and inward relative to the large boom section, whereby the tension forces within the chains serve to provide counter biasing forces to the latch plate mechanism.

Abstract: A telescopic boom is disclosed having a plurality of generally tubular boom sections each having its corners defined by angled corner plates converging upwardly and inwardly at equal angles relative to a central vertical plane containing the longitudinal axes of all boom sections when properly aligned. Boom shoes secured to the outer surfaces and near the inner ends of the angled corner plates of all boom sections except the largest section slidably engaging the adjacent angled corner plates of the next larger boom section; and similar boom shoes secured to the inner surfaces of the angled corner plates near the outer end of all boom sections except the smallest section slidably engaging the outer angled surfaces of the next smaller section.

Abstract: A telescopic boom for a crane, access or load platform or the like, having power transmission lines extending along the boom to its head. In order to avoid problems which arise with such power lines when the bottom is extended or retracted the invention proposes the use of a flexible carrier which extends between a point at the outer end of the base section and a point mid way along the extended sections of the boom between the head and the end of the base section. This enables the power lines to be protected both when the boom is extended and when it is retracted.

Abstract: An articulated aerial boom and an elbow linkage therefore permitting the proximal end of the upper aerial boom to rotate approximately 210.degree. about the proximal end of a lower aerial boom.

Abstract: An improved, high strength extensible crane boom is provided which has a plurality of elongated, tubular, telescopically interfitted, longitudinally bowed, prestressed boom sections, along with a low cost method of fabricating the respective boom sections. Each boom section preferably includes an elongated upper plate having a channel structure welded to the underside thereof to form a polygonal body; permanent bowing of the body is accomplished as an incident to the welding sequence by virtue of asymmetrical heating and subsequent cooling of the metallic boom components. The boom sections are advantageously pentagonal in cross section, and the separate sides of the channel structures are simultaneously welded to the upper plates to evenly heat the plates and minimize torsional distortion of the sections.

Abstract: A telescopic boom includes at least two sections and a manual section is sections being extended and retracted by a single hydraulic ram. A first coupling selectively connects or releases the ram's cylinder case from the second boom section while a second coupling connects or releases the other end of the cylinder case to the manual section. The first coupling includes a crank for coupling and uncoupling the cylinder case and second section. The second coupling includes a retrieval pin movable into position for connecting the cylinder case to the manual section when retracting the manual section within the second section, and releasable lock mechanisms are provided to lock the manual section in extended position. The method of operating the boom includes the step of pivoting the boom to a near vertical position prior to extending the manual section relative to the second section.

Abstract: The mast has a housing arranged to be mounted on the roof of a vehicle such as an emergency vehicle at the usual location of a vehicle light bar, whether or not a light bar is associated with the mast housing. A seal unit is located at the lower end of each telescoping mast section engaging the next outer mast section. The seal unit leaves the lower end of all mast sections unobstructed so that a tubular passage is formed from end to end of the mast. A retractable power supply cable is located in the passage of supply power to the electrical appliance mounted on the top of the mast. There are electrical plug connectors at each end of the mast for releasable connection with the electrical fixture at the top and with the vehicle power supply at the bottom of the mast. The mast is mounted on an offset pivot which simplifies the pneumatic-actuating system which tilts and telescopes the mast, and also enables the mast to tilt by gravity from telescoped retracted vertical to stored horizontal position.

Abstract: A telescopic boom arrangement comprises an innermost member, a plurality of intermediate tubular sections 12, and an outermost tubular member, each nested together, the arrangement being adapted so that sequential erection of the members from a stowed position is ensured, commencing with the innermost member, progressing with the next outer member and so on. Each intermediate member includes latching means 24 which serve both to lock the next inner member in a stowed position and to lock that member in an extended position. Unlatching of the latch means 24 of an intermediate member to allow extension of the next inner member is effected by fingers 23 on the next-but-one inner member when that member approaches its extended position. When the next inner member reaches its extended position, it is locked by means of latching means 24 engaging slot 25.

Abstract: In a telescopic crane comprising a telescopic shaft and a variable length boom pivotally mounted on the end of the shaft, the position of the boom relative to the shaft is controlled by a jack pivotally connected at one end to the shaft and at the other end to one end of a mast, the other end of the mast being connected to the boom, and ties connect the one end of the mast to the boom outwardly of the connection of the boom to the other end of the mask.

Abstract: In combination with a telescoping well mast structure having a fixed lower structure and a traveling upper structure, a device to time and actuate the extension and retraction of a racking platform pivotally attached to the upper structure. The device comprises at least one pulley secured within the upper derrick structure adjacent the crown and at least one lower pulley secured within the upper structure adjacent the lower end thereof. At least one cable extends from the platform around the upper pulley, the lower pulley and to a wheeled trolley adapted to travel along a portion of the lower structure. When the upper structure is extended the wheeled trolley is propelled along the lower structure by a pushing member on the upper structure until received into a catch housing on the upper portion of the lower structure. Once the wheeled trolley is restrained by the housing continued extension of the upper structure allows for the racking platform to extend by means of gravity.

Abstract: A multiple-element load handling shuttle assembly (10) which includes means to compensate for the downward deflection of the load carrying element of the shuttle under load. Each shuttle element (12, 14, 16, 20) is supported by a plurality of rollers (35, 43, 51, 57) which engage guide channels (36, 43, 52, 58) in an adjacent element. The end rollers (43c, 43d) on one of the elements are offset upwardly from the remaining rollers (43a, 43b) on that element and the corresponding guide channel (44) is flared upwardly at its outer ends to accommodate the offset rollers. The offset rollers and flared guide channel cause the shuttle assembly to tilt upwardly in its unloaded condition to at least partially compensate for the downward deflection of the shuttle assembly under load.

Abstract: To resist side deflection and buckling of the top and side plates in larger size multi-section telescopic crane booms, top plate lateral supports for the movable boom sections in the fully extended and fully retracted critical zones are provided to supplement the action of bottom lateral wear pads. The top plate lateral supports include adjustable spring bars on the sides and forward ends of the boom sections and coacting cam pads on the top plates of the boom sections at their forward ends and in the socketing zones when the boom sections are fully extended.

Abstract: An arrangement to support a drawworks and drilling mast in elevated position during drilling operations and which also functions to transport the drawworks and drilling mast includes a base support and an elevated support with jacks pivotally conncted to the base support and the elevatable support and extending herebetween. Wheels are mounted on the elevatable support for transporting the base support elevatable support, the drilling mast and drawworks carried on the elevatable support. Brace members are pivotally connected between the base support and elevatable support to retain the elevatable support in elevated position during drilling operations.

Abstract: The invention relates to a self-assembling telescopable structure comprising a plurality of members which can be slipped and unslipped into and from each other. For the assemblage and disassembling of the structure releasable fastening members are provided for the several component parts and reversible lifting means acting between the internal component part and its next intermediary component part.By outstretching such means it is possible to effect the unslipping of the internal component part from its next. By subsequently fastening the internal component to the external one or to an intermediate component and binding mutually the other intermediate components, it becomes possible, by contraction of said lifting means to have the mutually bound intermediate components into the unslipped internal component part. By repeating these steps, the structure is assembled, whereas, by reverting the step sequence the disassembling of the structure is obtained.

Abstract: Pipes for a telescopic mast have at least three guide grooves along their entire length, this is with the exception of the inner pipe having the smallest cross-sectional area which may not have guide grooves. All pipes except the pipe intended to be the outermost one in the telescopic mast have guide blocks attached to the lowermost portion of their outside. All pipes (4) except the pipe (4) intended to be the innermost one in the telescopic mast have guide blocks attached to the uppermost portion of their inside.

Abstract: An arrangement of tensile elements and rollers provides support for an extensible part against forces occurring in two directions perpendicular to the extension direction in which the extensible part is carried by a carrying part of conforming geometry. Two wire ropes form the tensile elements. First ends of each rope are attached to the top corners of one end of the carrying part and second ends of each rope are attached to the opposite bottom corners of the other end of the carrying part. The ropes extend in the extension direction from their carrying part attachments to the extensible part. At the extensible part, the ropes are passed over pulleys in two directions substantially transverse of the extension direction.

Abstract: A high-strength light-weight hollow boom section for a multi-section telescopic crane boom comprises a top wall, a bottom wall, and a pair of lateral walls, each lateral wall being located between the top wall and the bottom wall. Each of the four walls comprises a pair of spaced apart longitudinally extending members, a relatively thin plate extending between, overlapping and welded to the pair of longitudinal members, and a plurality of longitudinally spaced part transversely extending stiffeners of U-shaped cross-sections, each stiffener being welded to the plate and to the pair of longitudinal members. Each longitudinal member of a lateral wall is in edge-wise abutting relationship with and welded to the surface of a longitudinal member of one of the top and bottom walls. Each stiffener of a lateral wall also has its ends in abutting relationship with and welded to the surface of a longitudinal member of the top and bottom walls. Novel slide pad arrangements are also disclosed.

Abstract: To reduce the weight and increase the lifting capacity of a multi-section telescopic crane boom, a single hydraulic cylinder for the full extension and retraction of individual boom sections is anchored in the relatively stationary boom base section. A sled structure surrounding the single cylinder and moving therewith has guided engagement through plates fixed to the movable boom sections at or near their rear ends. Driving finger mechanisms on opposite sides of the sled are biased toward driving engagement with the plates of the movable boom sections and are retractable into chambers of the sled. A cooperative locking pin operating assembly for the movable boom sections is fixed on the forward end of the boom base section and includes power retracting devices which operate mating retracting cranks and locking pin sets individual to the movable boom sections when the retracting cranks are aligned beneath the power retracting devices.

Abstract: A telescopic mast having a plurality of elements comprising the mast wherein the elements are slidably arranged in relation to each other, together with cables for the erection of the mast, wherein the cables are before the erection of the mast connected to all of the elements and the erection of the mast is carried out by a successive sliding of each element on the element therebelow, further including provision for separating the cables of each element after the end of the hoisting operation of that element.

Abstract: A crane comprising a ground jib, a sliding jib telescopically engaged with the ground jib and movable in a telescoping direction, and a head jib pivotally mounted to the sliding jib. A catch hook is pivotally mounted to the head jib on a pivot axis which extends in the telescoping direction of the sliding jib and a catch member is connected to the ground jib in a position to engage with the catch hook when the sliding jib is protracted into the ground jib and when the head jib is pivoted toward the ground jib. The catch member extends in the telescoping direction so that the catch hook is disengaged from the catch member when the sliding jib is extended with respect to the ground jib. A method is also disclosed for stowing the head jib of the crane.

Abstract: Telescopable drilling mast means is transportable on and pivotally connected to a first trailer means. Setback tower means is pivotally connected to the drilling mast means and to the first trailer means.Second trailer means are provided with elevatable drawworks support means with drawworks, power source and rotary table thereon which elevatable drawworks support means is transportable on and pivotally mounted on the second trailer means.Means secure the first and second trailer means in end to end relation to position the drawworks support means and drilling mast means in longitudinal alignment, and load bearing means support the first and second trailer means in position on the earth's surface.

Abstract: A telescopic jib of a load-handling device, having telescopically extensible sections in the form of fluid cylinders. An annular sealing assembly is employed at the end portions of the sections, in the form of a sleeve which defines an annular space with the end face of the fluid cylinder of greater diameter and the side surface of the fluid cylinder of smaller diameter. A floating ring is mounted in the annular space and has seals which engage the external periphery of said smaller-diameter fluid cylinder and the end faces of the floating ring. Annular grooves are coaxial in the external peripheral surface at the end of each said fluid cylinder and in the end face of the respective one of said sleeves such that, a support ring is accommodated in each pair of annular grooves. A rope-and-sheave system having at least two runs symmetrically extending with respect of the longitudinal axis of the jib is used to govern the motion of the sections.

Abstract: An improved telescopic boom for a truck mounted hoist in which at least the middle telescoping section of the boom is fabricated from I-section structural steel having a central web, and upper and lower flanges, the flanges having inwardly facing surfaces lying in angled planes which are not normal to the plane of the web, and in which the trolley and fixed portion of the boom are fabricated of any other suitable structural material, and having at least two sets of identical rimmed wheels, one set mounted directly on the fixed section, and the other set mounted directly on the trolley, without the use of tilting arms, the two sets of wheels riding in opposite sides of the I-section material of the telescopic intermediate section, with the tread of the wheels carrying the load and with the rims providing lateral guidance thereby dispensing both with the mounting arms and with the lateral guide rollers.

Abstract: Disclosed is a rig for working on wells, and including a generally two-legged mast, with each leg constructed with a traveling pole telescoping about and along a gin pole. The mast may be so extended by means of a chain drive mounted on the traveling legs of the mast. Hydraulically-operated slips selectively lock each traveling leg to the respective gin pole to prevent the former from sliding down the latter. The mast may be lowered to, and raised from, a generally horizontal configuration for transport on a truck. A snubber, or other pipe gripping apparatus, may be suspended by the mast and folded under the mast as the mast is moved to a horizontal configuration. With the mast erect, a control console may be elevated by means of a winch line supported by the mast. The mast may be mounted on a skid carried by a truck, with the skid movable relative to the truck bed for the purpose of aligning the mast relative to a well.

Abstract: A telescopic boom is pivotally mounted on a frame of a vehicle and comprises telescopically disposed first, second, third and fourth sections. A double-acting cylinder has a rod thereof connected to the first section and a housing thereof connected to the second section. A first pulley is rotatably mounted on a forward end of the cylinder housing and a second pulley, having a larger diameter than the first pulley, is rotatably mounted on a rearward end of the cylinder housing. A first end of a cable is secured to the first section and is sequentially entrained over the first pulley, secured to the third section, entrained over the second pulley and has a second end thereof secured to a forward end of the first section. Thus, extension of the cylinder will function to extend the second section relative to the first section and simultaneously extend the third section at twice the linear speed as that of the second section.

Abstract: A hydraulically extensible crane boom includes a plurality of mutually innernested, telescopically associated inward and outward boom sections. Each section is made up of a pair of longitudinally extending, parallel, spaced apart upper structural shapes of substantial mass and strength, a relatively light top web integral with and extending between the upper structural shapes, a pair of longitudinally extending, mutually parallel, spaced apart lower structural shapes of substantial strength and mass, a relatively light bottom web integral with and extending between the lower structural members, and a pair of relatively light side webs each connected between one upper and one lower structural member. The distance between the lower pair of structural members is less than the distance between the upper pair of structural members.

Abstract: An antenna mast is constructed from telescoped tubes which are extended for deployment by hydraulic or pneumatic pressure, the tubes when extended, are latched to each other internally, permitting depressurization. A set of unlatch cones becomes sequentially effective to unlatch the latches, beginning from the top to stepwise telescope the tubes into each other. Spring biased latches are mounted on an insert in the bottom of tubes; the unlatch cones, except the highest ones, extend from the bottom of the inserts.

Abstract: A pair of safety stop blocks are welded to opposite sides of the fly section of a construction crane boom. The stop blocks have slide passages to receive the branches of a boom extension or load cable which is looped around an arcuate saddle near the base of the fly section. A pair of stop buttons are swaged to the extension cable branches between the saddle and the two stop blocks and are normally spaced somewhat from the stop blocks to allow the cable to seek an equal loading position around the saddle. The stop blocks carry cable retainer elements near the tops of the slide passages to prevent the escape of the cable therefrom. Should the extension cable fail in any region thereof under load, at least one swaged stop button will be engaged by a stop block of the boom fly section to positively arrest its retractive movement before any damage can occur.

Abstract: A telescopic boom comprises a base section, an inner section telescopable within the base section, an outer section telescopable within the inner section, and an actuator mechanism located within the outer section and operable to telescopically move the inner and outer sections relative to each other and to the base section. The actuator mechanism comprises an extendable and retractable elongated hydraulic cylinder or ram in the boom and comprising two relatively movable ram components, such as a cylinder housing and piston rod. One of the ram components (the piston rod) is connected to the base section and the other of the ram components (the cylinder housing) is connected to the inner section. An elongated cable support member is rigidly connected to the base section and extends into the boom. Means are provided to slideably support the first end of the hydraulic ram on the outer section and to slideably support the first end of the cable support member on the ram.

Abstract: A structure is provided for adjusting the lateral displacement of an outer second boom relative to a first, or base boom which receives and supports the second boom for telescoping movement relative thereto. A box-like retainer structure is provided to receive a pair of wear blocks which project from the retainer structure on each side of the second boom and are adapted to slidingly engage the inner surface of the sides of the base boom. A pair of threaded adjustment blocks are provided, one block inwardly of and adjacent each wear block for retaining the wear blocks against the base boom. Each adjustment block is threadingly engaged with a separate bolt and the distal end of each bolt opposite the adjustment block is retained within a bore of an upstanding wall to prevent each bolt from moving laterally relative to the second boom but to permit rotation of the bolts.

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.]. .Iadd.one end connected to the lowermost section or first ram and the other end connected to the innermost section .Iaddend.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.