Abstract: A hand held nibbling machine has a manipulatable housing with a drive head in which there is a downwardly opening passage. A tool assembly has an upper portion extending into the passage of the drive head, a lower portion for supporting a die, and a neck portion therebetween providing a throat portion between the upper and lower portions and into which a workpiece may extend. The upper portion of the tool assembly is releasably engaged in the passage of the drive head by interengaging surfaces about a portion of the outer surface of the upper portion of the tool assembly and about a portion of the wall of the drive head defining the passage, and these surfaces are disengageable by rotation of the tool assembly within the passage to move the interengaging surfaces out of alignment. A releasable fastener in the drive head is engageable with the upper portion of the tool assembly to secure the tool assembly in a rotated position in which the surfaces are interengaged.

Abstract: A combustion chamber arrangement and a method for the same, having a piston with a combustion trough adjacent an end thereof and a fuel injection nozzle for injecting fuel through nozzle holes against boundary walls of the combustion trough. The number of nozzle holes is based on the specific characteristics of the combustion trough depth, diameter and a dimensionless constant representation of the spin number of the combustion air entering the combustion trough.

Abstract: A fuel injection nozzle is proposed with an opening needle opposed against the flow direction and in which a spring loaded abutment body is guided for longitudinal sliding movement, which body with its free end protrudes into a blind pocket reservoir of the nozzle after a successful injection. Before the beginning of the injection this blind pocket reservoir is opened to open injection holes with different injection directions branching off from the blind pocket reservoir. Through a nozzle embodiment of this kind the damaging space in the blind pocket reservoir is substantially avoided and the proportion of the unburned hydrocarbons is substantially reduced.