A skid attachment for a carrying cart has an arcuate cross-section engageable with a pair of wheels at the front of the cart, and is held in position by the engagement of an edge of the attachment with the underside of the frame of the cart as forward motion of the cart is begun. The wheels rotate about the inner periphery of the attachment during this preliminary movement, in which the attachment simply rolls along the ground a few inches until the contact with the frame is made.

An electric motor driven inline hydraulic apparatus comprising a housing having end members closing said housing, an electric motor stator mounted in said housing, an electric motor rotor, a shaft on which the rotor is mounted is journalled in the housing and a pump is integrally formed on one or both of the end members. The shaft extends through an opening in the end member and is connected to the rotating group of the pump. Hydraulic fluid is supplied to the interior of the electric motor housing and flows through passages in the housing to the intake of the pump integral with the end member. The end member associated with the pump is formed with an enlarged chamber adjacent the inlet of the pump which functions to reduce the flow velocity and separate the contained air from the hydraulic fluid thereby reducing the operating sound level of the pump.

An electric motor driven inline hydraulic apparatus comprising a housing having end plates closing said housing, an electric motor stator mounted in said housing, an electric motor rotor, a shaft on which the rotor is mounted is journalled in the housing and a vane type pump mounted on one of the end plates. The shaft extends through an opening in the end plate and is connected to the vane rotor of the pump. Hydraulic fluid is supplied to the interior of the electric motor housing and flows through passages in the housing to the intake of the vane pump on the end plate. In one form, the vane pump delivers fluid through an outlet in the end plate on which it is mounted. In another form, the vane pump delivers fluid through an outlet in the pump housing.

The present invention accommodates differences in cracking pressures between check valves by determining a pressure on the input of a check valve that corresponds to a predetermined flow rate at the output of the check valve. A container is incrementally pressurized and the vacuum at a point on the output side of the check valve is monitored. Once fluid begins to pass through the check valve, the vacuum drops. At the predetermined flow rate, the pump cannot maintain a predetermined vacuum level since it cannot exceed a maximum speed. At this point the pressure applied to the container corresponds to the predetermined flow rate. An offset is added to the pressure to determine the minimum operating pressure.

In a pump in which dual plunger is reciprocated with cams attached to the rotating shaft of a motor, the delivery pressure of liquid is measured during a certain period in each cycle of the pump. By setting the pressure during the certain period as a standard pressure value, the motor is controlled so that the delivery pressure during the remaining period in each cycle approaches to the standard pressure value. In this pump, rotating-speed-priority control and pressure-priority control are alternatingly performed to decrease pulsation during delivering liquid.