Abstract: The present invention provides personnel lift devices that include at least one of six design features. Each of the design features is discussed individually. The lift device includes an operator's cage assembly exhibiting ease of operator access and a safety enhancing interlocked design. A control mechanism, requiring the use of both hands to maneuver the controlled device, further enhances the safety of apparatus of the present invention. Interlocked outriggers provide enhanced structural stability and safety. A telescoping mast of extruded metal design includes a plurality of tee slots and/or sliding engagement during extension and retraction of the individual mast stages. A transfer mechanism releasably positionable at a plurality of heights and includes a bumper/roller assembly that is either fixed or freely movable, depending upon the portion of the device being transferred that is bearing the weight thereof.

Abstract: A portable scaffold having tubular structural elements has necked fittings extending into the ends of the tubular elements and attached thereto by adhesive which is introduced through an entry port preferably provided by a porting ring sleeved on the neck of each fitting and opposed by an O-ring. The adhesive flows from the entry port through longitudinal and circumferential grooves in the neck between the porting ring and O-ring and vents through a vent port in the porting ring.

Abstract: There is provided an improved fluidic drive circuit for a fluid powered vehicle arranged to limit flow to an unloaded drive wheel. A restricting orifice is mounted in parallel with a pressure sensitive control valve to provide fluid power to the motor. A trickle flow is provided through the restricting orifice to maintain a minimum pressure to the fluid motor. The control valve, sensitive to pressure at the fluid motor, provides full flow only when the pressure in the fluid motor is sufficient.

Abstract: There is provided an over-translation sensing and centering apparatus for a scissors lift work platform comprising a linear cam arranged with electronic sensing means to detect an out-of-balance condition. For transmitting the relative angular position of the scissors members to linear movement of the cam, there is provided a control member pivotally mounted to the cam having bar links pivotally mounted to each extremity and connecting the control member to each scissors member. As each scissors member extends, the angle of the members with respect to the base of the vehicle causes the respective extremity of the control member to shift. As long as the scissors members move in equal opposing increments, the control member mounted on the linear cam rotates only, but if one member moves more than its counterpart, the control member is caused to shift and thereby move the linear cam.

Abstract: A translating mobile work platform is provided having a telescoping scissors mechanism comprising a lower and upper member confined to telescope within an intermediate member and having a system to equalize the motion of said upper and lower members, and further comprising fluidic circuitry to control the motion of the limbs of the scissors to provide level translational motion of the work platform by feeding fluid pressure from the upper portion of one cylinder to the upper portion of the other.

Abstract: An automatic locking device is provided for a telescoping work platform that includes: a base frame, a middle frame and a platform frame, the locking device comprises a first sliding member mounted in the middle frame, a first notch in the base frame for receiving said first sliding member and a first cam on said platform for disengaging said first member from said first notch, it also comprises a second sliding member mounted to the middle frame, a second notch in the base frame for receiving said second member and a second cam on said base frame for disengaging said second member from said second notch.