Abstract: A system for leveling a vehicle such as a recreational vehicle or the like includes three jacks in the form of hydraulic cylinders mounted to the vehicle frame. A series of manually actuated switches, oriented in a diamond pattern, are located within the interior of the vehicle and are interconnected with the jacks to provide selective extension of the jacks to adjust the attitude of the vehicle relative to level. A level sensor is mounted to the vehicle and is interconnected with the jacks and the switches, and an operating system is responsive to the level sensor for controlling operation of the jacks and providing information to the control panel. The operating system alerts the operator as to which of the switches should be actuated in order to level the vehicle, and also functions to cut-off extension of each jack when the level sensor has detected that the vehicle in the vicinity of the jack has attained a level condition.

Abstract: A mobile material handling machine includes a material handling element and an operator's control cab. A plate is pivotally attached to the material handling element in line with the operator's line of sight from the cab towards the element. The plate has first indicia on the edges thereof; second indicia on the top surface thereof; and third indicia on the bottom surface thereof. The first indicia is in line with the operator's line of sight when the material handling element is positioned at a predetermined angle relative to the operator's cab.

Abstract: A tip-over warning system for vehicles of the articulated type utilizes a swinging pendulum pivoted in a frame which is mounted on and simulates the stability triangle of the vehicle. The pivotal connection of the pendulum is at a scale distance relative to the frame corresponding to the location of the vehicle center of gravity. The side arms of the frame are variable in length and pivoted, allowing the apex of the frame to move. The apex is moved by a servo motor in accordance with the steering angle of the vehicle. The pendulum and frame are connected in an electrical circuit including a current source and an alarm device. When the pendulum touches a side arm of the frame the circuit is completed, thus energizing the alarm device.