US 4,828,046 AGranted

Vacuum-compression type percussion power tool with an auxiliary chamber

OwnerVladimir Pyatovinventor

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Abstract

A vacuum-compression type percussion power tool comprising a housing (12), a cylinder (14) fixed in the housing, a piston (16) reciprocating in the cylinder (14) from a reciprocating drive mechanism such as a crank mechanism (18) driven by an electric motor, or any other suitable drive, a working tool (24) installed in the front part of the power tool, and a floating striker (34) which slides inside the cylinder (14) in a space between a tail portion (26) of the working tool (24) and the lower end of the piston. In addition to a main working chamber (38), which is formed between the piston and a striker, it is provided with a sealed auxiliary chamber (54, 56), which is connected with the main chamber through a set of compensation holes (38) and a set of idle-stroke holes, so that when the striker performs a working stroke toward the working tool, in addition to the force applied to the striker from air compressed in the working chamber, it is additionally assisted by the force of a vacuum developed in the auxiliary chamber. As a result, it develops higher impact energy than a conventional tool of the same weight and overall length. The power tool also has a reduced level of vibrations transmitted to the housing because of a reduced peak pressure developed in the main working chamber.

Claims17

Dependent claims

A vacuum-compression type percussion power tool comprising:

housing means;
cylinder means located in said housing means and fixed therein, said cylinder means having inner and outer walls, and a closed bottom wall with an inner and outer sides, said closed bottom wall having a central opening;
reciprocating drive means supported by said housing means on the side thereof opposite to said bottom wall;
piston means slidingly guided in said cylinder means and driven by said reciprocating drive means;
a working tool with a tail portion inserted into said cylinder means through said central opening, said working tool having a flange which limits insertion of said working tool into said cylinder means;
a floating striker means having upper and lower end faces and located in said cylinder means for sliding therein between said piston means and said tail portion of said working tool inserted into said cylinder;
a main working chamber formed in said cylinder means between said piston means and said striker means;
a hollow casing surrounding a portion of said cylinder means and forming a space with said outer walls of said cylinder means;
an auxiliary chamber formed by said space of said hollow casing in combination with a space between said bottom wall, said lower end face of said striker means, and said inner walls of said cylinder means;
a first set of through holes formed in the wall of said cylinder means above said striker means, said first set of holes connecting said main working chamber with said auxiliary chamber
a second set of through holes in said walls of said cylinder means between said first set of holes and said bottom wall, said second set of holes connecting said space of said hollow casing with said space below said striker means, said holes of said second set having diameters substantially greater than those of said holes of said first set;
longitudinal grooves in said inner walls of said cylinder means, said grooves having a length greater than the axial length of said piston means.

9 more elements

A vacuum-compression type percussion power tool comprising:

a housing;
a cylinder located in said housing and fixed therein, said cylinder having inner and outer walls, and a closed bottom wall with an inner and outer sides, said closed bottom wall having a central opening;
a reciprocating drive mechanism supported by said housing on the side thereof opposite to said bottom wall;
a piston slidingly guided in said cylinder and driven by said reciprocating drive mechanism;
a working tool with a tail portion inserted into said cylinder through said central opening, said working tool having a flange which limits insertion of said working tool into said cylinder;
a floating striker having upper and lower end faces and located in said cylinder for sliding therein between said piston and said tail portion of said working tool inserted into said cylinder;
a main working chamber formed in said cylinder between said piston and said striker;
a hollow casing surrounding a portion of said cylinder and forming a space with said outer walls of said cylinder;
an auxiliary chamber formed by said space of said hollow casing in combination with a space between said bottom wall, said lower end face of said striker, and said inner walls of said cylinder;
a first set of through holes formed in the wall of said cylinder above said striker, said first set of holes connecting said main working chamber with said auxiliary chamber;
a second set of through holes in said walls of said cylinder between said first set of holes and said bottom wall, said second set of holes connecting said space of said hollow casing with said space below said striker, said holes of said second set having diameters substantially greater than those of said holes of said first set;
longitudinal grooves in said inner walls of said cylinder, said grooves having a length greater than the axial length of said piston;
first sealing means between said tail portion of said working tool and said central opening of said bottom wall;
and
second sealing means between said hollow casing and said cylinder, said first and said second sealing means seal said auxiliary chamber.

12 more elements

Dependencies are inferred from the claim text.