Abstract: A sawtooth wave form generating circuit in which the amplitude of the sawtooth wave form is automatically maintained at a constant value by passing the same through a variable gain amplifier, measuring the amplitude of the sawtooth wave form at the moment when it reaches its maximum value, comparing such amplitude with that of a standard voltage and adjusting the gain of the amplifier accordingly. This is done through the use of a capacitor which is charged upon the occurrence of the same pulse which discharges the capacitor of the sawtooth wave generator. The capacitor controlling the gain of the amplifier is charged under the control of a comparator amplifier having one input from the output of the variable gain amplifier and the other from a source of standard voltage. The sawtooth wave generator is particularly applicable for use in measuring phase differences between two events recurring at a variable repetition rate such as encountered in automobile ignition diagnosis.

Abstract: Engine diagnostic apparatus for displaying on a cathode ray tube the voltage conditions existing at each of the spark plugs which apparatus is intended for use with ignition systems in which the voltage pulses applied to the spark plugs are of such short duration that a cathode ray tube will not properly respond to the changes of voltage. The apparatus is effective to successively charge a capacitor to a value corresponding to the value of each voltage pulse and the voltages across this capacitor are used to control the vertical defection of the cathode ray tube. At the end of a first period of time following a voltage pulse, the capacitor is shorted. The capacitor is maintained shorted for a longer period of time less than the time between successive pulses so as to avoid undesired charging of the capacitor as a result of transient conditions.

Abstract: A pipe bending apparatus for bending large diameter pipe of either thin or thick walled construction. The pipe bending apparatus includes a bending shoe which is pivotably mounted to a frame member and a follower shoe which is operable with the bending shoe to receive a pipe therebetween for bending. The apparatus also includes a fluid motor which is operable to cause pivotal movement of the bending shoe and a clamping assembly comprising a plurality of rollers which are secured together to clampingly engage the follower shoe and the bending shoe to force them together such that the pipe is forced to conform to the arcuate configuration of the bending shoe as the bending shoe pivots. During such pivotal movement, the rollers of the clamping assembly traverse the arcuate surface of the bending shoe and the rear surface of the follower shoe clamping the pipe between the bending and follower shoe and causing the pipe to assume the configuration of the bending shoe in a rolling mill type operation.

Abstract: A vibration pick-up unit for balancing rotating bodies such as vehicle wheels comprises a housing having a tubular guide communicating with the interior of the housing, a plunger rod disposed telescopically in the tubular guide for axial and rotary movement, a permanent magnet attached pivotally on an end of the rod for engagement with a vibrating member of a wheel suspension system arising on rotation of the wheel, a first mounting member disposed within the housing and cooperating operatively with the tubular guide, the first mounting member being movable in response to the vibrations of the suspension system, a second mounting member disposed within the housing adjacent the first mounting member, light means disposed in the second mounting member for generating a source of light, photo-sensitive means disposed in the first mounting member and being responsive to the light means for converting the vibrations of the suspension system into an electric sinusoidal signal and circuit means connected operatively

Abstract: A hydraulic system and latching mechanism for a cab tiltably mounted to the chassis of a vehicle. The cab is normally disposed over the engine of the vehicle and is pivotally attached to the chassis at its forward end for movement through 90.degree.. The cab is powered by an air-motor-actuated hydraulic pump which energizes lifting cylinders disposed between the chassis and cab. When the system is energized, a hydraulically actuated latch is released prior to commencement of the tilting movement of the cab. A direction-control valve is employed which, when in the neutral or closed position, utilizes the pressures generated in the hydraulic system by the weight of the tilted cab in certain positions to assist the valve in sealing the reservoir port in the valve against leakage thereby preventing the cab from creeping.

Abstract: A proportional force amplifier having a cylinder separated by a piston assembly into a pressure chamber, a control chamber and a reservoir chamber, a spool valve mounted for axial movement within a bore in said piston assembly to selectively connect the control chamber to either the pressure chamber or the reservoir chamber, the piston assembly moving in response to the change in pressure between the pressure chamber and the control chamber a distance equal to the distance of movement of the spool valve, the spool valve being connected for actuation by a resilient compensating rod and being pressure balanced.