Abstract: The tool comprises a piston which can be propelled under the action of the explosion of a mixture of gas and air to drive an element, a first, gas-metering chamber, a second, gas-air mixture-preparation chamber, designed to communicate with the first chamber, and a third chamber designed to communicate with the second chamber, which is delimited by the piston and which is a throttling and propulsion chamber. The invention is ideally applicable to securing tools.

Abstract: The tool comprises a piston which can be propelled under the action of the explosion of a mixture of gas and air to drive an element, a first, gas-metering chamber, a second, gas-air mixture-preparation chamber, designed to communicate with the first chamber, and a third chamber designed to communicate with the second chamber, which is delimited by the piston and which is a throttling and propulsion chamber. The invention is ideally applicable to securing tools.

Abstract: An internal combustion apparatus is disclosed having a linear output. A metered quantity of gas fuel is transferred between a cylinder head and the disc of a plunger reciprocable in a principal chamber between top and bottom end of stroke positions. In the displacement of the plunger to its bottom end of stroke position air and fuel are intimately mixed in a one-way flow path around the disc including nonparallel and/or burred orifices in a perforate plate attached to the plunger. The fuel may be liquefied gas fuel in which case it may be vaporized by the combustion gases exhausted from the principal chamber to the surroundings through an annular exhaust zone coaxial of throttle passageways for carrying fuel from the metering piston to the principal chamber. Alternatively, a pressurized gas fuel may be used in which case the pressurized gas is utilized in the operation of the plunger.

Abstract: A percussion apparatus, for example for driving nails or staples, having an auxiliary piston which when released thrusts a main operating piston to an intermediate position. The auxiliary piston transfers a metered quantity of gaseous fuel together with combustion supporting air to a space between the main piston and cylinder head separating the auxiliary piston cylinder from the main piston cylinder. The explosive mixture in the space is then ignited and the main piston is thrust in a first direction displacing a driver member and simultaneously the auxiliary piston is thrust in the opposite direction to its initial position where it is retained until released to start another operating cycle; the main piston automatically returns to its initial position as the combustion gases are exhausted to the atmosphere.