Abstract: A mobile aerial lift platform vehicle of the type having an upstanding pedestal and an elevating assembly mounted on the pedestal to raise and lower the work platform while maintaining the center of gravity of the platform within the base area defined by the wheels of the vehicle. The improvement is that the pedestal is pivotally mounted to the chassis of the vehicle for pivotal movement about a first axis extending fore and aft of the chassis and about a second axis extending from side to side of the chassis. Two hydraulic rams for provided, each of which will pivot the pedestal about one only of the axes, so that the pedestal may be leveled even through the vehicle is on unlevel ground.

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 movable pedestal scaffold having two sets of wheels on the scaffold base to permit the scaffold to be rolled horizontally while the mast of the scaffold is in a vertical position. A transport frame is mounted for vertical movement on the mast, with such movement being powered by a hydraulic cylinder. A first set of wheels is mounted on the transport frame to support the scaffold at (1) a tilted position relatively near to vertical when the transport frame is close to the base member, and (2) at a tilted position substantially inclined from vertical when the transport frame is away from the base member. A second set of wheels is mounted on the transport frame closer to the mast and to the base frame then the first set of wheels on the transport frame, the first and second sets of wheels on the transport frame acting together to support the scaffold on an elevated horizontal surface as the scaffold is raise to or lowered from that surface.

Abstract: A steering and drive system for a four-wheeled vehicle (10) with two non-steering and non-driving wheels (16, 17) at one end of the vehicle, in which the system includes two wheel brackets (23, 32) at the other end of the vehicle, each wheel bracket having a motor-driven wheel (18, 19) mounted thereon, and each wheel bracket being mounted on the vehicle for turning about a vertical axis which passes through the angle of rotation of the wheel thereon, and a double-ended hydraulic cylinder (35) having a housing (36) fixed to the frame (15) of the vehicle and a reciprocating piston (41) whose ends are connected by links (47, 53) to the two wheel brackets to provide a tie between the wheels and Ackerman steering.

Abstract: A mobile scaffold unit having a wheeled base frame and a horizontal work platform, interconnected by upper end lower scissors sets. Each scissors set has a power arm and a stabilizer member, and the upper and lower pivotally connected power arms have a hydraulic ram connected therebetween. The upper and lower power arms are pivotally connected to the platform and base frame respectively and have a length greater than the length of the platform, with the ram being connected to the power arms beyond the platform. The width of the scissors set is considerably less than the distance between the wheels on opposite sides of the frame, enabling the scissors set to be disposed between the wheels and to be mounted to the base frame at a level considerably below the upper surfaces of the wheels. The power arms are made up from three beams connected in a fork manner and provide two parallel beams where the forces are greatest and a single beam where forces are relatively low.

Abstract: A pedestal scaffold having a base member with an upwardly extending mast and a work cage mounted thereon for vertical movement. Retractable outriggers with ground-engageable pads are extendable outwardly on the cage side of the scaffold and lockable into support position to provide a large support area for the elevated work cage. Ground-engageable casters are mounted on the base and the cage and the cage is releaseably locked to the base. When the base and cage are locked together, the scaffold can be moved horizontally on the base and cage casters with the mast being vertical. When the cage is unlocked for vertical movements, scaffold weight is transferred from the cage casters to the non-rolling outrigger pads so that the scaffold cannot be moved along the ground when the cage is elevated. If the cage-side outriggers are not properly braced, the cage can be unlocked from the base but cannot be raised off the ground.

Abstract: A parking brake system with transmission interlock means is provided with means to override the interlock means. The parking brake system is spring-actuated and fluid pressure released with means to vent the transmission controls when the parking brake is engaged. A special interlock valve is provided to selectively override the normal system to prevent venting of the transmission.