Abstract: A foot control mechanism for a dental apparatus has a tiltable actuation member mounted on a base part and an arrangement for holding the tiltable actuation member in a neutral position, which requires sufficient force to move the actuation member in either direction from the neutral position to a switch position. To accomplish this, the structure includes a mounting arrangement utilizing a pair of spaced-apart bearings extending parallel to each other which bearings receive projections on the other element and, preferably, a catch member is provided which provides a resistant force from movement from the neutral position.

Abstract: A distributor-type fuel injection pump is provided with a hydraulic injection adjusting mechanism whose injection adjusting piston adjusts the cam gear unit for driving the pump plunger to execute strokes corresponding to the desired position of the start of injection. The injection adjusting piston defines a control space on one side and a spring space receiving a return spring on the other side. The control space is connected via a throttle bore with the pump interior space which is filled with fuel by a delivery pump. The fuel pressure is adjusted by a pressure control valve. To prevent unstable pressure vibrations on the injection adjusting piston, which leads to defects in the operation of the fuel injection pump, the spring space is connected on one side with the suction side of the delivery pump via a first throttle and on the other side with the pressure side of the delivery pump via a second throttle having a smaller throttle cross section.

Abstract: A fuel injection pump for internal combustion engines, in which for supplying a very rapid pressure rise in the interior of a fuel injection pump, a pressure control valve controlling this pressure is modified such that it is reliably closed upon cold starting of the engine. To this end, a control piston of a pressure control valve is acted upon on its back side by a restoring spring which is supported on one end by an adjustable stop, which is acted upon by the pressure building up in the fuel injection pump and in so doing seeks to bias the restoring spring. This causes a closure of an outflow throttle controlled by the control piston, so that all the fuel pumped by a feed pump remains in the pump interior and contributes to increasing the pressure. With the aid of this pressure, a very rapid adjustment of an injection adjusting piston (4) is effected in a direction of an early onset of fuel injection that promotes cold starting and warmup.

Abstract: A fuel-injection pump for internal combustion engines, in particular a distributor fuel injection pump, which comprises a pressure control valve, a timer and conduits for communicating a feed pump with pressure chambers of the pressure control valve and the timer. The fuel-injection pump further comprises an adjustable outlet valve and a relief conduit communicating the return chamber of the pressure control valve with the adjustable outlet valve. An outlet conduit extends from a shut-off orifice of the pressure control valve, and a pressure valve is arranged in the outlet conduit for controlling flow therethrough.

Abstract: A fuel injection pump for internal combustion engines which has an rpm-proportional injection onset adjusting device, a pressure control valve controlling the supply pressure (phd f), a cold-start acceleration device having a pressure valve associated with the pressure control valve, and a full-load stop, controlled by an adjustment device, for limiting the maximum full-load quantity injected by the fuel injection pump. The adjustment device has a piston, which is acted upon on one end by the supply pressure in the suction chamber of the injection pump and on the other end by a pressure (p.sub.a) that is made to differ from the supply pressure by means of two separate throttles. The two throttles have the effect that if the pressure valve is closed, the adaptation device is subjected to a differential pressure which is approximately equal to that when the pressure valve is opened, and so the full-load courses attained in normal operation and in cold operation are virtually identical.

Abstract: In a fuel injection pump for an internal combustion chamber a device for an "early" adjustment of a fuel injection onset includes a check valve for controlling the fuel injection onset, for example in case of a cold start or low atmospheric temperatures. An unloading bypass conduit with an adjustable flow valve is connected to the check valve in parallel so that the adjustment makes possible the control of the beginning of the characteristic line of the pump relative to the characteristic line of the internal combustion engine. The device includes a pressure control valve which has an outlet opening controlled by a control piston. The cross-section of the outlet opening defines the adjustment of the characteristic line of the pump to the characteristic line of the engine.

Abstract: A device for surface treatment of teeth characterized by a vortex chamber divided by a diaphragm into an upper and lower portion, a reservoir discharging through an orifice which is positioned in the first portion to be closed by the diaphragm while in a first position, a pressurized gas line discharging into the first portion and extending from the first portion to a nozzle of the device so that an abradant discharged through the orifice into the first portion is mixed with the gas for discharge from the nozzle of the hand piece. The second portion of the vortex chamber includes a spring biasing the diaphragm toward the first position and a control line which receives pressurized gas from a branching line and has a regulating valve for venting the gas pressure in the second chamber to enable the diaphragm to move to the second position to enable flow of the abradant into the first portion.

Abstract: A device for cleaning teeth by projecting water and a carrier gas containing an abrasive at the surface characterized by a nozzle having at least one water discharge aperture and a gas discharge aperture adjacent the water discharge aperture, the water discharge aperture being connected to a source of water, the gas discharge aperture being connected to a mixing chamber which in turn is connected by a channel to a source of carrier gas containing abrasive and by a separate channel to an additional source of abrasive-free gas which is directed into the mixing chamber through an acceleration jet so that the abrasive-free gas having a higher acceleration energy in comparison to the carrier gas mixes with the carrier gas to accelerate it as the abrasive-free gas passes through the mixing chamber and the discharge aperture.