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. Each proximity switch is connected in an electrial circuit having a built in time delay or lock out feature for applying power to the aerial work platform after a predetermined time delay and thereafter interrupting power when either guard bar member strikes or comes into contact with an external object or obstruction.
The invention relates to a balanced supporting arm, comprising a substantially elongate structural member which is mounted on a supporting assembly for tilting movement and which is provided with at least one bellows mounted under at least one end of the supporting arm. According to the invention, the bellows has an inoperative condition wherein it is at least substantially empty and an operative condition wherein it is filled with a gas under a predetermined working pressure. The balanced supporting arm comprises means for detecting the tilting speed of the supporting arm and, further, means, connected with the means for detecting the tilting speed, for bringing the bellows from the inoperative condition into the operative condition when the means for detecting the tilting speed detect that the tilting speed exceeds a predetermined value.
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.about.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.
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.
The invention is a small, maneuverable, self-propelled tracked vehicle equipped with a boom having a tool attached to an extendable section of the boom. The vehicle is small and light enough to enter and be used in places, such as residential yards, in which traditional vehicles with buckets and digging tools, because of their size and weight, cannot be used. A three-stage gear pump powers the tracks and the boom on the bucket or digger. The vehicle has four outriggers to stabilize the vehicle during use, the outriggers arranged substantially perpendicular to each other and at angles of approximately forty-five degrees from the longitudinal axis of the vehicle.
The invention is a small, maneuverable, tracked vehicle capable of being equipped with a tool such as, but not limited to, buckets, diggers, tree spades, trenching devices, and augers. The vehicle is small and light enough to enter and be used in places, such as residential yards, in which traditional vehicles with buckets and digging tools, because of their size and weight, cannot be used or other places where flotation is a concern. The preferred vehicle has four outriggers to stabilize the vehicle during use, the outriggers arranged at an angle to a longitudinal axis of the vehicle.
