Abstract: An electro-hydraulic operating system for an extensible boom includes one or more hydraulic cylinders for imparting relative motion between the boom sections to retract the boom according to an electronically stored program of sequences of movement and speeds. A source of pressurized hydraulic fluid is fed through appropriate control valves which include solenoid valves in fluid communication with a source of pressurized hydraulic fluid. The solenoid control valves are supplied with control currents proportional to the desired flow rates of fluid to the hydraulic cylinders in order to achieve speed and position control according to the stored program. A metering valve structure is provided for operation in conjunction with the solenoid control valves.

Abstract: The metering valve includes a housing assembly defining a metering cavity therein. At least one inlet port supplies fluid to be metered to the cavity, and at least one output port outputs metered fluid from the cavity. A valve seat in the cavity is disposed between the input and output ports, a pilot chamber and a pilot port to the pilot chamber. A control element in the pilot chamber is displaceable in proportion to the pressure of pilot fluid input to the pilot port. A valve spool is mounted for reciprocating movement in the metering cavity, and the spool is coupled to the control element and displaceable therewith. The spool has a metering flange for operative engagement with the valve seat in the cavity. The position of the metering flange with respect to the valve seat controls variable flow rates of fluid between the input port and output port of the valve housing assembly.

Abstract: A telescopic jib includes a base part, and at least one telescopic part telescoped in the base part. A shift mechanism extends and retracts each telescopic part. The base part and each telescopic part includes an upper semi-box shaped section part, and at least one of the base part and the telescopic part includes a lower section part having shell segments adjoining each other. Each shell segment has an outwardly curved shape.

Abstract: A boom collar for an outer telescopic boom section of a telescopic boom includes a tension belt forming at least a bottom surface and first and second curved corner portions of the collar. First and second sliders are disposed in the first and second curved corner portions, respectively, and the first and second sliders translate along the tension belt about a longitudinal axis of the said telescopic boom. First and second webs are connected to either side of the tension belt, and prevent the first and second sliders from moving in a direction of the longitudinal axis.

Abstract: An operating system for telescoping a telescopic boom for a crane, particularly a boom having three or more telescoping sections, enabling the boom to be extended and retracted automatically under load according to a predetermined sequence which optimises the load capacity of the boom and the stability of the crane. The boom may be switched rapidly between modes of operation in one of which all of the telescoping sections may extend or retract and in another of which at least one telescoping section is maintained in the fully retracted position.

Abstract: A carrier track system for a multi-section telescopic boom structure having a base section, a mid section and a fly section. A pair of flexible tracks carrying flexible hydraulic hoses and electrical cables are positioned within the base and fly sections and are respectively connected between the inner end of the mid section and the bottom wall of the base section; and the inner end of the mid section and the bottom wall of the fly section. A pair of spaced, longitudinally extending channels are positioned within the base and fly sections for guiding the flexible tracks, reinforcing the side walls of the base and fly sections, providing housing for fixed hydraulic and electrical conduits, and providing a support for the wear pads on the inner end of the mid section. A dual rod hydraulic cylinder is connected between the telescopic boom section so that each section can be selectively operated independently, or in a synchronized or proportional manner relative to each other.

Abstract: A transportable multi-purpose crane includes a platform having outriggers disposed at opposite ends thereof. A turntable is rotatably mounted to the platform between the outriggers on opposite ends of the platform, and has a center axis of rotation. A riser boom, having a first end and a second end, is pivotally mounted to the turntable at its first end, and the second end supports a first load carrying device. The riser boom points in a first direction with respect to the center axis of rotation, and is a telescoping boom. An upper boom, having a first end and a second end, has its first end pivotally mounted to the second end of the riser boom. The second end of the upper boom supports a second load carrying device. The upper boom points in a second direction, opposite the first direction, with respect to the center axis of rotation, and is a telescoping boom.

Abstract: A weight for operating the lift-limiting switch of a crane, especially a telescoping-boom crane, is composed of two identical castings connected together by a hinge at one side and having a lock on the opposite side which, when actuated, holds the two members around the crane cable but which can be opened to allow the weight to be placed over the cable or to be removed therefrom.

Abstract: A vehicular low profile, self propelled aerial work platform having an articulated parallelogram boom assembly including a lower boom assembly having pairs of compression and tension arms pivotally connected between a support frame on the vehicle and a floating frame, and an upper boom assembly having pairs of compression and tension arms pivotally connected between the floating frame and a riser connected to the proximate end of a telescopic boom assembly having a work platform connected to the distal end thereof. The ends of the tension arms in the upper and lower boom assemblies which are pivotally connected to the floating frame, share the same pivot connection so that when the articulated parallelogram is in the folded position the tension arms are inter-digitated and lie in the same common plane so that the vehicle can be maneuvered through a low doorway, in the order of six feet, seven inches.

Abstract: A tie rod extendable and retractable telescopic axle assembly wherein a pair of axle beams are slidably mounted in a box beam integral with a vehicle chassis. Steering linkage and associated wheel assemblies are mounted on the outer ends of the axle beams, and the inner ends of the axle beam within the box beam are telescopically mounted relative to each other which provides an increased wheel base when the axle beam are moved outwardly of the box beam. A hydraulic cylinder and piston rod assembly is mounted between the box beam and wheel assemblies so that the hydraulic cylinder and rod assembly function not only as an actuator for extending and retracting the axle beams but also as a tie rod for the wheel assemblies.

Abstract: An articulated riser system for aerial access equipment wherein a parallelogram linkage is provided by a support frame, a riser frame assembly, and a pair of substantially parallel arms pivotally connected at each end to the support frame and riser frame assembly. The parallel arms are positioned one above the other and the lower arm is provided with a multicell cross-sectional configuration larger than the tubular cross-sectional configuration of the upper arm so that heavier loads can be supported by aerial access equipment than if both parallel arms had the same cross-sectional configuration. A trough is provided in the upper surface of the lower arm so that the upper arm is nested therein when the parallelogram linkage is in its fully lowered and fully raised positions.

Abstract: A vehicular self-propelled aerial work platform wherein a lower telescopic boom assembly is connected to a riser frame assembly having an upper telescopic boom assembly also connected thereto. A work platform is connected to the outer end of the upper telescopic boom assembly. Both the lower telescopic boom assembly and the upper telescopic boom assembly can be elevated and extended to increase the reach of the aerial work platform. The lower telescopic boom assembly comprises tubular telescoping boom sections connected at opposite ends between a support on a turntable and the riser frame assembly, with a telescopic cylinder extending interior of the boom sections and connected at opposite ends between the same members providing a telescoping parallelogram boom mechanism, with hydraulic controls with interlocks for operating the boom in a predetermined sequence.

Abstract: A self-storing maintenance stand for a scissor lift aerial work platform wherein a pair of arms are freely pivoted on each side of a stack of pivotally connected scissor arms at the medial portion thereof. An arcuate saddle plate is provided on each end of the pair of arms for engaging protruding end portions of the pivot pins of the next adjacent scissor arms. A weight is connected to the end portion of one of the arms so that the arms will freely pivot to a non-working or stored position.

Abstract: A synchronization device for an articulated parallelogram boom assembly having a floating frame connected between an upper work platform carrying boom assembly, and a lower vehicle mounted boom assembly. The synchronization device is mounted on the floating frame and includes a slidable member and compression and tension links connected between the slidable member and the upper and lower boom assemblies. The synchronization device is constructed and arranged to maintain the included angles of the adjacent upper and lower boom assemblies substantially identical during the luffing movement of the boom assemblies so that the work platform is maintained parallel to the ground plane.

Abstract: An alignment device on a crane boom having telescopic boom sections and a side stowable boom extension swingable from a stowed position to a working position and connectable to a nose assembly on a boom section by upper and lower clevis connections on each side of the nose assembly. The alignment device includes an abutment assembly mounted on the nose assembly boom section, and another abutment assembly mounted on another boom section. The abutment assemblies engage each other during relative retracting movement of the boom sections and forcibly engage the end of the boom extension to align the apertures of the clevis connection and nose assembly to facilitate the insertion of the pin therein.

Abstract: An extension and retraction system for a four section telescopic boom having simultaneous and equal extension and retraction of the telescopic sections, wherein a pair of hydraulic cylinders are mounted exteriorly of the boom for extending and retracting the inner mid section relative to the base section; a pair of extension chains or cables are connected between the base section and the outer mid section, and between the fly section and the inner mid section; and a pair of retraction cables are connected between the base section and the outer mid section, and between the fly section and the inner mid section. The extension and retraction chains and cables are positioned within the boom sections to thereby be protected from damage.

Abstract: A control panel enabling and automatically disabling system is coupled between a source of electrical power and a plurality of motion controls on an aerial work platform. Upon activation of a pushbutton type power enabling switch, power is coupled to all the motion controls for a predetermined fixed time period which when activated will couple power to a respective motion producing mechanism such as a boom actuator. If none of the motion controls are activated by an operator within this time period, a timer times out and the panel thereafter becomes inactive by interrupting the electrical power. However, if a motion command is effected by actuation of any one of the motion controls during this time period, the timer is automatically reset to zero time and held thereat until all motion commands cease, at which time the timer is restarted. The enabling switch cannot be defeated by a continuous activation thereof. The enabling switch must be released and pushed again to start a new cycle.

Abstract: An electrical deactivation circuit and a two piece overhead guard assembly including two separately movable bar members which extends upward and over the head of an operator located on the upper work platform of an aerial work platform. The guard bar members are connected to the frame of the upper work platform by a pair of movable support assemblies, the movement of which actuates impact detection induction type proximity switch means to interrupt electrical power applied to the electrical control circuits and stop the engine powering the aerial work platform. Each movable support assembly includes a pair of spring loaded mechanical subassemblies including a pair of clamp members between which is located an elongated coil spring whose stiffness is varied in accordance with the distance separation of the clamps. An inductive type proximity switch is located in the lower end portion of each spring to sense movement of the inner end of a respective guard bar member.

Abstract: A forklift truck having a fork assembly connected to a telescopic auxiliary boom articulated to a telescopic main boom. The telescopic and articulating features of the auxiliary boom in conjunction with the telescopic feature of the main boom increases the range and reach of the fork assembly to above ground heights and to below ground depths.

Abstract: A carrier track assembly for extensible and retractable boom machines wherein the carrier track assembly is positioned within the telescopic boom sections and has one end connected to the extension and retraction fluid cylinder in the base boom section and the opposite end connected to the inner end of the next adjacent extensible and retractable boom section, the carrier track assembly being supported by the extension and retraction fluid cylinder when the boom sections are fully extended. An elevated support member is secured to the fluid cylinder at a position between the inner end of the base boom section and the end connection of the carrier track assembly on the fluid cylinder, the carrier track assembly being reversely bent upon itself and supported by the elevated support member when the boom sections are fully retracted.