Abstract: A trenching machine has an elongated chain type digging implement that is pivotally mounted for vertical adjustment and movably mounted to a main frame thereof for lateral adjustment. The pivot coincides with the power shaft, and the elongated chain type digging implement is supported so it can be moved laterally in order to position the digging implement adjacent either side of the digging machine main frame and anywhere therebetween to excavate closely adjacent to buildings and other structures. The mechanism for moving the digging implement can be manually actuated by a hand crank arrangement. The main frame of the machine can be tilted laterally to either side to align the digging implement to excavate a vertical ditch. The tilting of the machine also makes it easier to manually move the digging implement laterally.

Abstract: A valve device for insertion in the fuel line of an internal combustion engine between the engine and the fuel pump therefor and adapted to impede the flow of fuel to the engine in response to a reduction in pressure in the lubricating oil system for the engine. The device is insensitive to variations in fuel pressure and flow rate by virtue of having a fuel pressure balancing piston associated with the valve and having an oil pressure sensitive piston substantially isolated from the fuel pressure and flow.

Abstract: An excavation digging tooth locking device is disclosed for frictionally maintaining a digging tooth in a female reception pocket in matingly wedged relation. The locking device is a sliced section of an extruded member compressively wedged into and filling a varying dimensioned gap between the tooth and the pocket. The locking device has a tubular portion with a slit across its longitudinal dimension and a pair of divergent wing portions extending from the opposing faces of the slit. The wing portions have tapered distal ends of reduced cross section. The interface of the wing portions and the tubular portion have enlarged cross sections. The inner perimeter of the tubular portion engages a reduced end bight section of the inner tooth wedge portion, the opposing faces of the slit engage the deepest sections of recessed detents adjacent the bight section, and the wing portions engage the tapering shallower sections of the detents.

Abstract: A pressure ratio valve is installed in an internal combustion engine having a pressurized air supply and an air actuatable throttle control means for limiting the engine RPM in response to a pneumatic control signal. The pressure ratio valve continuously senses both the engine oil pressure and the pressure of the engine compressed air system and generates the pneumatic control signal in response thereto. When the oil pressure-air pressure ratio decreases below a predetermined magnitude, an unsafe engine oil pressure condition is indicated and the pressure ratio valve generates a pneumatic control signal which causes the throttle control means to limit the engine RPM to a safe level.

Abstract: A pressure ratio valve is installed in an engine having an engine protection means for reducing the engine RPM to a safe level in response to an engine oil pressure below an acceptable level. The engine further includes a fuel pump for supplying fuel at a pressure linearly related to the engine RPM. The pressure ratio valve continuously senses both the oil pressure and the fuel pressure of the engine and reduces the engine oil pressure below the acceptable level of the engine protection means in response to a fuel pressure-oil pressure ratio in excess of a predetermined magnitude. This action by the pressure ratio valve causes the engine protection means to reduce the engine RPM to a safe level.

Abstract: A fuel shut-off valve is described having a body with a cylindrical bore divided into first and second sections by an annular tapered shoulder. A piston is slidably positioned in the bore and inlcudes an O-ring that seats against the tapered shoulder or seat to isolate the first and second sections of the bore. One end of the piston is provided with a second O-ring sealingly engaging the bore and isolating that portion of the bore on one side of the face of the piston from the remainder of the bore. A fuel inlet passage communicates with the first bore section and an oil inlet passage communicates with a second bore section. An outlet passage communicates with the first bore section at a position axially displaced from and disposed on the opposite of the tapered seat from the first inlet passage.

Abstract: A starting system for use with an internal combustion engine is shown utilizing a container of compressed volatile fluid to be injected into the engine upon starting. The fluid is delivered from the container through the actuation of a solenoid that subsequently provides a metered quantity of the fluid to the engine. The solenoid is connected in electrical series with the engine starting switch, a timing switch, and a thermostatic switch. Operation of the starting switch results in the opening and closing of the timer switch to alternately break and complete the series circuit; the thermostatic switch is normally closed and is opened to break the series circuit when the engine temperature reaches a predetermined value.

Abstract: A trenching machine has an elongated chain type digging implement that is pivotally mounted for vertical adjustment and movably mounted to a main frame thereof for lateral adjustment. The pivot coincides with the power shaft, and the elongated chain type digging implement is supported so it can be moved laterally in order to position the digging implement adjacent either side of the digging machine main frame and anywhere therebetween to excavate closely adjacent to buildings and other structures. The mechanism for moving the digging implement can be manually actuated by a hand crank arrangement. The main frame of the machine can be tilted laterally to either side to align the digging implement to excavate a vertical ditch. The tilting of the machine also makes it easier to manually move the digging implement laterally.