Abstract: A lift arm for a skid-steel loader, in which a pair of right and left lift arms are divided in two so that they are constituted as first arm portions and second arm portions. Each of the first arm portions is constituted as a long member which is constituted from a sheet metal material and a hollow portion is formed from a proximal end to a front end of the first arm portion. Reinforcing plate-shaped bodies are fixed on both side faces from a central portion to the front end. Each of the second arm portions is constituted from a plate-shaped body and constituted between a front wheel and a loader main body so as to be inserted loosely. With this structure, it is possible to provide the lift arm which enables an entire length of the skid-steer loader to be shortened.

Abstract: A retractable light is provided with a light to extend and retract in a housing. A motor for driving a sprocket is mounted in the housing or light assembly and a gear rack is mounted in the other. The gear rack has a series of apertures so that debris is conveyed into the apertures. Another embodiment provides a housing with a first guide member, connected to a light assembly by a second guide member. A motor and a gear are mounted in one of the housing and light assembly. A gear rack is mounted in the other of the housing and the light assembly. In another embodiment, a rechargeable battery is powered by a solar cell with a first circuit for powering the motor with a first voltage and a second circuit for powering the light source with a second voltage that is less than the first voltage.

Abstract: A well drilling apparatus includes multiple, transportable, modular, pre-assembled sections which include a substructure and multiple mast sections. These pre-assembled sections allow for a quicker complete rig-up of the well drilling apparatus at ground level in a horizontal direction, without the use of a crane. Once the assembly has been completed at ground level, the mast is raised to its vertical operating position via mechanisms for raising and lowering dog tails. During transport, the guide rails are built-in to the mast sections and the crown block is attached to the traveling block, thereby facilitating the rigging-up process. The mast may be lowered after the drilling operation has been accomplished without interfering with any blow-out preventer devices that may have been placed on the wellhead while the structure was at its raised operational level.

Abstract: A hinged pole having a base plate secured to the lower end thereof with the base plate having a plurality of upstanding brackets secured thereto. A cart is provided which is mounted on the foundation of the pole and is secured thereto and which is connected to the pole. The cart includes a power cylinder which is connected to the pole and which is used to lower the pole from its upstanding position to a horizontal position. The pole may be serviced when the pole is in its horizontal position. When the servicing of the pole has been completed, the pole is raised to its upright position and re-secured to the foundation therefore. The cart is then removed from the pole for use at a different location.

Abstract: The device is specially designed to facilitate the collapsing of towers (4) in movable structures that are frequently assembled and dismantled, such as, for example, in the field of the staging of events. The invention consists in establishing, on the tower (4), a fixed, lower base (2) of scant height, which is securely connected to the general structure (1) on which the tower (4) is to be raised, whilst the remaining, principal sector of said tower (4) is connected to the base (2) via a hinging shaft (3), there being established, between the principal sector (4) of the tower and the fixed structure (1), a connecting rod (6) joined in an articulated manner to both elements, which together with those elements and with the base (2) forms a deformable quadrilateral.

Abstract: The present invention relates to an anchor to be used with a basketball support pole, and more particularly to an anchor that facilitates ease of assembly and mounting of a basketball support pole and a backboard/hoop assembly attached thereto. The anchor may include an anchoring base and a lifting system. In use, the lifting system may rotatably attach to the support pole and allow a user to conveniently assemble and raise the basketball backboard/hoop assembly and support pole into a position for playing basketball.

Abstract: A hinge mechanism comprises first and second chock plates and an adjustable shaft. Each of the chock plates includes an aperture in the form of a figure of eight, the first and second circular portions of which are similar and are connected by a neck portion of a width less than the diameter of the circular portions. The shaft is longitudinally adjustable between a first retracted position in which the sections of the shaft aligned with each of the chock plates have a cross-section which corresponds to the circular portion of the aperture and a second extended position in which the sections of the shaft aligned with each of the chock plates have a cross-section of a diameter which is less than the width of neck portion.

Abstract: A hinge mechanism comprises first and second chock plates and an adjustable shaft. Each of the chock plates includes an aperture in the form of a figure of eight, the first and second circular portions of which are similar and are connected by a neck portion of a width less than the diameter of the circular portions. The shaft is longitudinally adjustable between a first retracted position in which the sections of the shaft aligned with each of the chock plates have a cross-section which corresponds to the circular portion of the aperture and a second extended position in which the sections of the shaft aligned with each of the chock plates have a cross-section of a diameter which is less than the width of neck portion.

Abstract: A deployable and erectable watch tower for accommodating personnel in an upper chamber thereof is disclosed. The deployable and erectable watch tower is translocatable by haulage and includes an erectable unit; a base frame; a hydraulic actuator for erecting the erectable unit, an upper chamber of the erectable unit having transparent windows and a roof; sideways foldable legs for supporting the base frame on the ground; and ground stilts for supporting the legs on the ground. The deployable and erectable watch tower may further include armoured elements attached at least to the erectable unit.

Abstract: In the design of load bearing members for use in work machines, it is oftentimes beneficial to minimize the weight of such structures which, in turn, may allow for increased payloads and decreased cycle times of the work machine. A load bearing arrangement for use with a work machine of the type having a platform is provided. The load bearing arrangement comprises a plurality of pieces connectable to form a member structured and arranged for pivotable attachment to the platform. A weldment connects at least two of the pieces where at least one weldment is simulated for effects of heat on at least one of the pieces subject to the weldment.

Abstract: The invention concerns a material transloading equipment unit with an undercarriage and a turntable connected with this undercarriage by means of a track ring, on which an arm that can be pivoted by means of at least one hoisting cylinder is pivot-mounted. According to the invention, on the one hand at least one additional pivot point for the arm is provided on the turntable and/or on the boom foot, and at least one additional pivot point is provided in the arm or in a pivot plate on the arm. This allows a number of possible combinations for the kinematics of the arm.

Abstract: A portable surveillance system having an easily transportable skid-type base structure that forms a support for a portable tower apparatus. Stabilizers are extendably mounted to the base structure. The tower components include a base member affixed to the base plate, a pivot bracket affixed to an upper end of the base member, a tower member pivotally mounted to the pivot bracket on the base member and one or more removable tower members that may be installed to achieve a desired height for the tower once it is pivoted to an upright orientation by manipulating a cable and pulley system. Various equipment mounts are provided on the tower to mount equipment such as an aerometer, a tower light, a wind direction vane, a video camera, a microwave telecom dish, or other equipment thereon. The ability to rapidly deploy the tower of invention enables rapid deployment for surveillance and other uses.

Abstract: A tall tower is divided into an upper section with a tower top and a lower section with a tower bottom. The sections are hinged together. The lower section is hinged to a tower base. A telescoping crane is attached to a lift point on the lower section. The crane is extended to lift the sections to the vertical position with the lower section resting on the base and the tower top of the upper section near ground level. A heavy load is attached to the tower top end using a small ground crane while the tower top of the upper section is near ground level. The telescoping crane is attached to another lift point on the upper section to partially lift the upper section, which is supported in this position. The telescoping crane is relocated and reattached to the lift point on the upper section. The telescoping crane is fully extended to raise the upper section and load to vertical above the lower section.

Abstract: A support tower for large structures such as wind turbines generators, microwave structures, high voltage transmission lines or the like, constructed of telescopic sections with the lowermost section having an edge portion pivotally connected to a foundation to enable the tower sections to be transported to the site of installation. The tower sections are assembled at the installation site in a nested relationship, each within the adjacent lower tower section. The large load is mounted on the upper end of the uppermost tower section and the nested tower sections are then tilted upwardly to a vertical position. After the tower is tilted to its vertical position and securely connected to the foundation, the telescopic tower sections are vertically extended to position the load in a vertically elevated position.

Abstract: The present invention is directed to an arrangement for a drilling rig and a process for erecting, disassembling, and laterally moving the drilling rig. In particular, the present invention is directed to an arrangement which permits moving the drilling rig to a closely spaced nearby well following the completion of one or more previous adjacent wells without disassembling the entire structure. Further, the present invention is directed to an arrangement that facilitates the rapid erection and later disassembly of a drilling rig.

Abstract: A passive optical control system for an aerial device comprising an optical signal source, an electrically passive modulator coupled with an electrically passive input mechanism located in or on an electrically isolated work station, and an optical receiver, wherein the source transmits an optical signal across a dielectric gap to the modulator which modulates, attenuates, or otherwise changes the optical signal to produce a changed optical signal corresponding to a control input provided by the input mechanism and sends the changed optical signal back across the dielectric gap to the receiver whereafter the changed optical signal is converted to a proportional electrical signal, thereby safely and efficiently maintaining the electrical isolation of the work station.

Abstract: A jib is supported for its luffing movement by a luffing rope mounted to a longitudinally intermediate portion of the jib. The jib has a truss structure with upper and lower beam members respectively overhanging upward and downward of load action line which connects a lifting point with a support pin.

Abstract: A support tower for large structures such as wind turbines generators, microwave structures, high voltage transmission lines or the like, constructed of telescopic sections with the lowermost section having an edge portion pivotally connected to a foundation to enable the tower sections to be transported to the site of installation. The tower sections are assembled at the installation site in a nested relationship, each within the adjacent lower tower section. The large load is mounted on the upper end of the uppermost tower section and the nested tower sections are then tilted upwardly to a vertical position. After the tower is tilted to its vertical position and securely connected to the foundation, the telescopic tower sections are vertically extended to position the load in a vertically elevated position.

Abstract: In order to be able to shift a leader (18), which is disposed on a travelling chassis (10) via a carrying mechanism (16), both towards the front and also towards the rear into a substantially horizontal position, the carrying mechanism (16) has at least one guide arm (24) which is adjustable in length and which comprises a double-acting hydraulic working cylinder.

Abstract: A mounting assembly for a davit to support a platform by supporting lines, is secured by a receptacle flush mounted on an elevated floor of a building. The mounting assembly is secured and moved into engagement with the mounting assembly by a socket of a mounting assembly receiving the davit engaging the assembly with the mounting assembly by engagement blocks which engage a locking member in the receptacle upon tilting of the davit mounting assembly toward a vertical position.

Abstract: While a crawler body 110 is traveling, infrared sensors 144 and an elevational difference calculator 132 incorporated in a controller 130 detects the magnitude of a step present ahead of the crawler body 110. A safety speed calculator 134 calculates a safety speed based on the magnitude of the step detected and on the position of the platform 116 relative to the crawler body 110, which position is detected by various detectors 141˜143 and by a position calculator 133. A comparator 135 compares this safety speed with the traveling speed of the crawler body 110, and if the current speed of the crawler body 110 is greater than the safety speed, then the comparator 135 outputs a warning signal. Upon receiving this signal, a restrictor 136 controls a valve controller 131 to reduce the speed of the crawler body 110 such that the crawler body 110 can travel over the step safely.

Abstract: A support base for distributing a concentrated load over a contact surface is disclosed. The support base includes a body formed of moldable polymeric material having a top surface and a generally planar bottom surface. At least one recess is integrally formed in the top surface for receiving a support member. The support member transfers the concentrated load to the planar body. Furthermore, at least one through bore is provided in the support base, and the through bore extends from the top surface to the bottom surface of the support base for receiving a fastener. The through bore has a shaft portion and a relatively oversized cavity portion adjacent to the bottom surface for receiving fasteners such as nuts for securing bolts, as well as, bolt heads of different sizes and configurations. The support base has many advantages over the prior are for example, the base may be attached to different interface bracketry without be modified.

Abstract: A conventional cargo or passenger-type van (typically about 14-24 feet in length) is fitted with a boom assembly that is readily transported with the van in a collapsed position and substantially parallel to the van roof, but can be elevated to a substantially vertical position, and quickly extended upwardly to full height. Where four booms are used, full height may be about 65 feet, or even more. A support frame is provided which substantially supports a main pedestal exteriorly of the roof and connected to the booms and an extension cylinder, to the van's main frame, including initially telescopic support posts disposed inside the van interior which do not impede access to the van interior from the side and rear doors, and which leave the center of the van interior essentially unobstructed. A pivotal connection for the first boom about which it moves from a transport to a substantially vertical position is mounted slightly to the rear of the centerline of the rear axle of the van.

Abstract: Conventional lift arm arrangements for construction machines include a pair of lift arms that are welded fabrications forming box-beams. The lift arms are typically connected by a cross tube that is welded to the inner walls of each lift arm. This type of construction creates an extremely heavy arrangement that requires several very labor intensive welding operations to manufacture. The present invention provides a lift arm arrangement that includes lift arms that are made of one-piece, cast members. Each lift arm includes an integral abutment portion that defines a surface that is adapted for welding to a cross tube assembly. The surface is configured to be spaced laterally from the inner side surfaces of each lift arm. Being so positioned, the stress concentrations created by the welded joint are moved to a location that is removed from the juncture between the cross tube assembly and the side surfaces of the lift arms.

Abstract: Collapsible structure are provided having a first base panel and a second panel, each having a foldable frame member that has a folded and an unfolded orientation, and a material partially covering the frame member when the frame member is in the unfolded orientation, with the material assuming the unfolded orientation of its associated frame member. The second panel is flexed so that the first and second panels define an interior space, with the second panel having opposing first and second end edges that are coupled to the outer periphery of the first panel. The second panel can have two or more supporting frame members to allow the collapsible structures to be provided in different configurations and sizes. In addition, the first base panel can be replaced by a fabric or similar piece of material that is coupled to the first and second end edges of the second panel. The second panels can be coupled within, or outside, the outer periphery of the first base panel or fabric.

Abstract: Counterbalancing apparatus for a lamp column in which an upper part of the latter is pivotally mounted on a fixed lower part so that the upper part can be swung down for lamp servicing, comprises a compression spring assembly or a hydraulic ram arranged to have a bearing engagement with the column parts and to be linked to the lower part in order to safely restrain lowering of the upper part or to counterbalance and assist or effect raising thereof. Alternatively a single or double acting ram or rams have a removable pivotal connection with respective column parts so as to act between them. For mobility and case of application the apparatus is wheel mounted.

Abstract: A new Tilting Pole System for allowing an individual to quickly and easily perform maintenance upon an object conventionally supported by an elongated pole. The inventive device includes a lower pole, an upper pole pivotally secured to a top end of the lower pole by a hinge, a shaft rotatably projects within a capped end of the upper pole, and a fastener removably projects through a lower portion of the lower and the upper poles. The fastener is removed when tilting the upper pole with respect to the lower pole. The shaft secures a utility device such as an antenna, a flag, a satellite dish or a lamp. An electrical outlet is secured to the lower portion of the lower pole for providing electrical power to various electric tools in a remote area.

Abstract: A pneumatically telescoping mast adapted for mounting an electrical fixture is disclosed. The telescoping mast includes a pneumatic control system to extend the mast from a retracted position to an extended position. The mast is made up of adjacent telescopic sections, each section slidable relative to an adjacent section, each section slidable between the retracted position and the extended position. Mechanical arrangements are disclosed for pivoting the mast between a generally horizontal and a generally vertical position, including drive mechanisms operable independently of the pneumatic control system and adapted to securely maintain the mast at any desired angle between the horizontal and vertical positions.

Abstract: Disclosed is a rotational flagpole pivotally mounted to a rigidly affixed base with a tongue and slot combination that enables the flagpoles to rotate around the pivot. The flagpole can also be locked in place to prevent rotation. The rotational flagpole thereby permits rotation of the top end of the flagpole to within a few feet of the ground in order to provide improved access to the top end for maintenance.

Abstract: A portable collapsible tower including a frame, at least one stationary tower member fixed to the frame and at least one movable tower member movable along the exterior portion of the stationary tower member relative to the stationary member. A coupling, movably couples the stationary and movable tower members for movement along the exterior portions. At least one cable located along the exterior portions of the tower members, is used to extend and retract the tower members and a light or tool support bar. As the tension in the one or more cables is altered by a tension altering device, the support bar and tower members are moved between fully extended and fully retracted positions.

Abstract: A device for raising and lowering a pole or other elongated support structure has a stand on which the elongated support structure is mounted. The stand is pivotally connected to a base. An actuator, such as an hydraulically actuated cylinder, raises and lowers the elongated support structure by the use of a control rod which is connected to the stand and to the actuator, and which traverses to cause the stand to pivot relative to the base to raise and lower the support structure.

Abstract: A method of constructing curvilinear structures utilizes an armature mast, an armature boom having a vertically and horizontally pivotable arm terminating in a reinforcing rod (rebar) tying guide, and associated hardware. The tying guide is aligned with a piece of vertical rebar, and a separate piece of horizontal rebar is placed adjacent and generally perpendicular to the vertical rebar for securing thereto. The tying guide is then moved to engage an adjacent piece of vertical rebar, and the horizontal piece is bent inwards for securing thereto. As the armature boom is moved about the mast and progressively raised, further vertical and horizontal pieces of rebar can be brought into juxtaposition and secured, thus generating a non-planar grid of rebar. An impermeable layer is placed over the grid, and a hardening material is applied to form a rigid shell. Further outside and inside base layers may be applied, and further outside and inside surface layers may be applied.

Abstract: Mounted on a vehicle (10), the mast (20) of a boring rig is supported by an erection hinge (18). The erection hinge (18) is provided on a first carriage (19) having a support cylinder attached (28) to it for the purpose of support and erection of the mast (20). The hydraulic erection cylinder (24), attached to the vehicle (10), is connected to the second carriage (21). The mast (20) is extended to an oblique angle by the hydraulic erection cylinder (24). The final phase of the erection of the mast (20) is completed by the retraction of the secondary take-in cylinder (27), which connects the two carriages together. When in a horizontal position, the mast (20) can be guided in a longitudinal direction in order to have a more favorable position of the center of gravity on the vehicle (10).

Abstract: This invention relates to a portable, easy-to-put-together, strong, durable mast support system for use in field operations where an antenna mast, or other similar mast, needs to be safely and quickly assembled, raised and supported. The mast support system is comprised of few pieces which stack in a compact longitudinal bundle for easy transportation to or from a site of use or for storage. When packed for shipment, the entire assembly may easily be placed on the top of a car or other vehicle. The mast support system is assembled through use of slideably interlocking pieces with hitch pins or clips. No special tools are required. The mast support system features a rotatable mast base alignment and support receptacle to enable one person to safely raise and lower a long mast after an antenna or other device has been safely affixed to the top of the mast when the mast is still at a safe horizontal ground-level position.

Abstract: A target assembly utilizes a post that is so supported on a base as to enable it to maintain positions deflected from its normally upright orientation.

Abstract: A column is attached at a base flange to a plate of a base member by way of an offset horizontal pivot, and can be pivotally raised and lowered by means of a ram. The pivot lies in the general plane of the flange and the plate so that, when the column is fully lowered, the overall height of the unit in the region of the base member is little more than the length of the flange.

Abstract: A mast to base connection for a storage and retrieval machine which incorporates a pin connection between the mast and the base. The base of the machine is formed as a plurality of elongated plates standing on edge with upwardly extending lugs formed integrally with the plates. The mast has similar lugs formed at its lower end which interleave with the lugs on the base. The mast and base are factory prealigned prior to shipment and line bored to receive connecting pins which can be precisely matched to each bore. The invention includes a method by which the mast is assembled to the base at a job site by laying the mast down on the base and inserting one of the connecting pins into the lugs, and then tilting the mast about the pin until the remaining lugs are aligned for insertion of a second pin.

Abstract: A device (10) for transferring an invalid includes a beam (11) comprised of two telescopically received tubes (12,13); a track (14), slidably engaged within said beam capable of supporting a rolling trolley (15) and connected winch (16) for providing a vertical lifting force. A seat (18) is appended to winch (16) by a winch yoke (19). The device is secured transversely to the roof surface of an automobile by clamps (21,22) mounted to the beam and track. The invalid is positioned within the seat and lifted vertically by the winch and is then slided into or out of the automobile as desired.

Abstract: A process for erecting a inflatable building structure which is especially adapted for housing plants. The process includes the steps of(1) installing a plurality of support posts in the ground or other suitable base;(2) attaching a roof structure formed from one or more inflatable membranes to the plurality of support posts; and(3) inflating the inflatable membrane.Preferably the inflatable membrane has peripheral rigid support members which are each attached to a row of associated posts. The roof structure formed from the inflatable membrane(s) together with rigid support members may be initially laid on the ground before being elevated.There also may be provided an upper securing cable extending across the top of the or each inflatable membrane which may initially be in the slack condition but which is subsequently tensioned before inflation.

Abstract: A mast for measuring or illuminating purposes, especially for flight navigation lights or for wind measuring devices, which is designed as a glass-fiber or carbon-fiber reinforced plastic mast.

Abstract: A crane, and a boom assembly for a crane, include an outermost boom portion having the area between its front chord members being substantially open. Inner lacing members extend in intersecting pairs between diagonally opposing pairs of chord members for strengthening the boom. The various lacing members in the latticework construction for a crane are connected to the chord members using reusable clevis pin assemblies of a predetermined tolerance. This enables it to be easily assembled and to be readily disassembled for ease of transport and storage in a compact state. It also produces a rigid structure having substantially no internal residual stress.

Abstract: A drilling derrick assembly is described which provides for the elevation above ground level of the assembly's working floor which supports both the mast and the drawworks. Prior to erection, the elevatable equipment floor is carried on a supporting substructure, and a mast is pivotally connected to the elevatable floor in a reclining position. When the assembly is erected, the mast is pivotally raised and attached in place, and other rigging steps can be carried out. Through the use of an integrally mounted sling and winch assembly or, alternatively, through operation of the assembly's traveling block, the entire equipment floor is elevated to the desired level.

Abstract: A temporary power line tower assembly and method of installing the same to serve emergency needs in restoring power service when a permanent tower is damaged or in need of repair. The temporary tower assembly includes a plurality of prefabricated sections the base section of which incorporates a gimbal joint and a rotary joint axially of the base section and normal to the gimbal axes at their point of intersection. The base section is provided with a lockout device operable to restrain all pivotal movement about the three pivot axes of the gimbal and the rotary joints to permit storage, transit and handling of the base section without risk of damage or injury to personnel.

Abstract: A silo has a guide arranged along the silo container, and the guide has a stop at the upper portion of the silo. A coupling element can slide along the guide, which can be coupled with a tippable loading frame of a transport vehicle by a cable. This arrangement simplifies the loading and unloading of the silo onto or off of the transport vehicle.

Abstract: A device for articulating a base of a mast for raising a mast carrying an antenna into an upright position, the device comprising a mast-engaging member which includes a collar (6) provided on one side with a means for affixing the base (2) of the mast to the member and, on its other side, is provided with two parallel depending plates (8), each having a slotted opening (10), said openings (10) open out at free ends (9) of the plates in order to form a pair of spaced forks, the openings being at least equal in size to the diameter of a journal (11) having a horizontal axis and supported by a stake means (12) that is fixed to the ground (4), whereby the forks permit the member to be articulated about the journal.

Abstract: The invention relates to a device for raising a mast from a ground lowered position to a raised position at which it is supported on a base. The lower end of the mast is supported on the base by a connecting link comprising an upper fork and a lower fork joined by a link. The lower fork is fixed relative to the mast, but can be articulated with the mast about a mast-raising axis. The upper fork of the connecting link is connected to the lower part of an arm of a lever along a folding axis which axis is orthogonal to the mast-raising axis.

Abstract: A power actuator on the base section of a multisection 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 method for stretching and folding an extension jib in a wheeled type crane including a telescopic boom, and a suspension-rod-supported compression column type extension jib to be supported in a flat posture at the fore end of the boom in stretched state through right and left jib foot portions rotatably engaged with horizontal boom point pins extending transversely of the boom at the fore end thereof, the method including the steps of (a) providing on opposite sides of the extension jib right and left jib foot portions disengageably engageable with the boom point pins, one of the jib foot portions being rotatable relative to the boom about an axis extending in the axial direction of the jib; (b) stretching the jib from a folded position in which the top and bottom sides of the jib are disposed in an upright posture along one side of the boom, by engaging the one jib foot portion with the boom point pin on the folding side and turning the boom into an inclined position from a horizontal position, rotating th

Abstract: A pickup truck derrick assembly includes a base frame, a derrick A-frame pivotally mounted on the base frame, a derrick frame erection subassembly, a frame support and locking subassembly and a cable compensation system. In one form, the frame erection subassembly includes an elongated track. A roller or carriage subassembly rides on the track and engages the A-frame. Movement of the carriage along the track raises and lowers the A-frame. The A-frame is held in an erected position by support braces pivotally connected at one end to the base frame. Each brace slidably engages a sleeve mounted on the A-frame. A locking mechanism automatically secures the braces to the sleeves when the A-frame is erected. In another form, the erection subassembly includes lead screw actuators combined with the support braces to raise and lower the A-frame and lock the frame in position.

Abstract: A jacket of an offshore platform has a special internal structure of which one side coincides with one side of the jacket but an opposite side is spaced from the corresponding opposite outer side of the jacket. The jacket is made by a rolling-up process while lying recumbent, the special internal structure being made first and then being used to provide the reaction points for the rolling-up of outer-side-forming trusses of the jacket, which are of greater height, when erected, than the special internal structure and carry angle parts which are to form the said outer opposite outer side of the jacket.