Patent EP0123502A2 successfully refreshed from Google Patents.
EP0123502A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Portable power tools
Assignee: Individual
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Filing: 1984-04-17
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Granted: —
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Expires: 2004-04-17
Abstract
Abstract A portable powertool comprising a housing (1) defining a combustion chamber (2) and a cylindrical chamber (2a) having a reciprocating piston (3) therein. The combustion chamber has an opening defined by a valve seat (5) closable by a poppetvalve (6) and serving as an inlet atone side (7a) for unburnt gases or vapourized fuel admitted under pressure and an outlet at an opposite side (7b) for spent gases. An ignition assembly (13) is provided for igniting unburnt fuel in the combustion chamber which is synchronized with the closure of the poppet valve. The combustion chamber and the poppet valve are shaped and arranged such that unburnt fuel admitted through one side of the valve seat opening will sweep the spent fuel of a preceding ignition cycle from the combustion chamber out through the other side of the valve seat opening.
Inventors
- 👤 Alphonsus Gerardus Gulielmus Veldman
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 19:40
CPC Classifications
A; A01; A01G; A01G3/00; A01G3/02; A01G3/033; B; B25; B25C; B25C1/00; B25C1/08; B25D; B25D9/00; B25D9/06; B25D9/10; B25F; B25F3/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
314 words
A portable power tool comprising a body (1) defining a cylindrical bore slidably and sealingly housing a reciprocal pistion (3) for a movement in one direction from a first position through a power stroke into a second position and in an opposite direction through a return stroke, said body further defining a combustion chamber (2) associated with and arranged for communication with said cylindrical bore at the end remote from the second position of the piston, said combustion chamber being arranged to receive a gaseous or vaporised fuel mixture for ignition and combustion, inlet/outlet opening means (5) provided in said body and communicating with said combustion chamber for the admission of fuel to the combustion chamber and emission of residual gases therefrom, and valve means (6) mounted within said body for movement between an open condition and a closed condition relative to said inlet/outlet opening means; said valve means and inlet/ outlet opening means and said combustion chamber being shaped and arranged such that with the valve means in the open condition and the piston at its first position, gaseous or vaporised fuel under pressure is directed into and around the combustion chamber in a manner scouring the combustion chamber of residual gases from the preceding cycle of operation of the tool and sweeping said residual gases out through the inlet/ outlet opening means prior to movement of the valve means to its closed condition there being ignition means (13a) actuable to ignite the fuel charge in the combustion chamber with the valve means in the closed condition so that subsequent combustion thereof creates an elevated pressure condition within said combustion chamber and such elevated pressure can be passed to the cylindrical bore and piston therein to cause rapid movement under power of the piston, through its drive stroke towards the second position, said piston being arranged to effect a required power assisted operation.
Claim 2
Dependent Claim
314 words
A portable power tool comprising a body (1) defining a cylindrical bore slidably and sealingly housing a reciprocal pistion (3) for a movement in one direction from a first position through a power stroke into a second position and in an opposite direction through a return stroke, said body further defining a combustion chamber (2) associated with and arranged for communication with said cylindrical bore at the end remote from the second position of the piston, said combustion chamber being arranged to receive a gaseous or vaporised fuel mixture for ignition and combustion, inlet/outlet opening means (5) provided in said body and communicating with said combustion chamber for the admission of fuel to the combustion chamber and emission of residual gases therefrom, and valve means (6) mounted within said body for movement between an open condition and a closed condition relative to said inlet/outlet opening means; said valve means and inlet/ outlet opening means and said combustion chamber being shaped and arranged such that with the valve means in the open condition and the piston at its first position, gaseous or vaporised fuel under pressure is directed into and around the combustion chamber in a manner scouring the combustion chamber of residual gases from the preceding cycle of operation of the tool and sweeping said residual gases out through the inlet/ outlet opening means prior to movement of the valve means to its closed condition there being ignition means (13a) actuable to ignite the fuel charge in the combustion chamber with the valve means in the closed condition so that subsequent combustion thereof creates an elevated pressure condition within said combustion chamber and such elevated pressure can be passed to the cylindrical bore and piston therein to cause rapid movement under power of the piston, through its drive stroke towards the second position, said piston being arranged to effect a required power assisted operation.
Claim 3
Dependent Claim
65 words
A portable power tool as claimed in Claim 1 wherein the inlet/outlet opening means (5) comprises a single circular valve opening or port to the combustion chamber defined by a frusto-conical valve seat and closable by a single poppet valve assembly (6) having a single frusto-conical valve head (6a) arranged for mating engagement on said valve seat, the poppet valve assembly being said valve means.
Claim 4
Dependent Claim
96 words
, A portable power tool as claimed in Claim 1 or Claim 2 wherein said body (1) and said valve means (6) define a receiving chamber (14 x ) for receiving a prescribed quantity of combustible gaseous fuel under pressure from a supply source whilst said valve means is in a closed condition, said receiving chamber being arranged to communicate with a fuel jetting nozzle directed towards the inlet/outlet opening substantially simultaneously with movement of the valve means to the open condition and on sealing of the receiving chamber from the source of gaseous fuel supply.
Claim 5
Dependent Claim
61 words
A portable power tool as claimed in any one of the preceding claims wherein the cylindrical bore is provided with at least one exhaust opening (21) towards the second position of the piston for the exhaustion of at least some spent gases from said cylinder as said piston approaches or reaches its second position at the end of its drive stroke.
Claim 6
Dependent Claim
152 words
A portable power tool as claimed in Claim 4 wherein return a bias means is provided to at least initiate return of said piston to its first position, wherein said bias means comprises a resilient buffer (19) provided within said cylindrical bore. at the second position of said piston and arranged to be contacted and compressed by said piston on reaching the second position, said buffer being arranged to return the piston to at least a position sealing the at least one exhaust opening (21) from communication with the combustion chamber; residual gases in the combustion chamber and communicating part of the cylindrical bore on the inner side of the piston thereafter undergoing a sufficiently rapid drop in temperature to create a negative pressure condition to enable the remainder of the return stroke of the piston to be effected or assisted by atmospheric pressure acting on the outer side of said piston.
Claim 7
Dependent Claim
99 words
A portable power tool as claimed in any preceding claim, wherein said valve means is normally biased to the closed condition and is movable against the open condition by trigger mechanism (9), said trigger mechanism including release means for enabling the valve means (6) to return rapidly under said bias to the closed condition and said valve means further having an inner end part (108) which is arranged to effect striking of an actuating plunger or projection of a piezoelectric crystal assembly (138) to provide a spark for immediate fuel ignition with the valve means in the closed condition.
Claim 8
Dependent Claim
80 words
A portable power tool as claimed in any one of the preceding claims wherein said body has an end wall part partially closing the outer end of the cylindrical bore remote from the piston first position and defining or provided with a guide (17) through which an impact drive member (18) is slidably located, said impact drive member being disposed longitudinally of the cylindrical bore and having an inner end part connected to the piston (3) for reciprocal movement therewith.
Claim 9
Dependent Claim
102 words
A portable power tool as claimed in any one of Claims 1 to 6 wherein said body (1) defines a further chamber (27) in communication with the outer end part of the cylindrical bore remote from the piston first position, said further chamber having inlet (27b) and outlet (26') means and being arranged to receive a charge of fluid as the piston moves from its second position to its first position on the return stroke, the arrangement providing that said charge of fluid is capable of being rapidly expelled by movement of the piston through its power stroke to said second position.
Claim 10
Dependent Claim
66 words
A portable power tool as claimed in Claim 8 wherein the fluid to be expelled is air admitted under atmospheric pressure through the inlet means (27b), and the outlet means (26) comprises an elongate tubular member arranged for insertion in the ground to deliver the charge of expelled air under pressure to an area below ground level to effect soil shattering and aeration for agricultural purposes.
Claim 11
Dependent Claim
87 words
A portable power tool as claimed in Claim 8 or Claim 9 wherein the further chamber (27) is of cylindrical form and disposed co-axially of said cylindrical bore, said further chamber being of smaller diameter than the diameter of the cylindrical bore and slidably sealingly housing a further piston (3 x ) coupled to said piston (3) of the cylindrical bore for reciprocal movement therewith; the diameter differences providing for elevation of the pressure to be exerted on the fluid to be expelled during the power stroke.
References Cited (Backward Citations)
No citation records indexed.
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