Tool driving or impacting – Drive controlled by relative axial movement of tool
Reexamination Certificate
2001-02-20
2003-09-16
Smith, Scott A. (Department: 3721)
Tool driving or impacting
Drive controlled by relative axial movement of tool
C173S115000, C173S127000, C173S206000, C173S207000
Reexamination Certificate
active
06619407
ABSTRACT:
BACKGROUND OF THE INVENTION
The subject invention relates to an improved air-operated hammer. The uses for which the subject air-operated hammer find application include, but are not limited to, pilehammers, concrete breakers, forging hammers, and compacting.
Current air-operated hammers typically have an external compressed-air source which supplies pressurized air to the hammer, for example via an air hose. This pressurized air is used to lift the hammer's head such that gravity, and/or additional mechanisms, can drive the hammer head down, for example to drive a piling into the ground. Once the hammer head drops and reaches the object it is intended to contact, the hammer can again begin to accept pressurized air in such a fashion as to lift the hammer head back up.
Accordingly, the expansion of the received pressurized air supplies the work needed to raise the hammer head during the operation of the hammer. The rate at which the hammer head is raised is therefore dependent on the pressure and the rate of flow of the pressurized air into the hammer. In order to raise the hammer faster, an air source with a larger flow rate and/or higher pressure is needed.
Once the hammer head is raised, for example to a predetermined position, the flow of pressurized air into the hammer is typically shutoff by some sort of valve on the hammer in order to allow the hammer head to drop during the down stroke. Accordingly, during the period of time that the hammer head is falling the compressed-air supply is typically not supplying air to the hammer.
The subject invention pertains to an improved air-operated hammer which can utilize a pressurized air reservoir located near a pressurized air entrance of the hammer. This pressurized air reservoir can continue to receive pressurized air even when the hammer head is falling and, preferably, can enable pressurized air to enter the hammer at a faster rate than the hammer's external compressed-air source can supply.
BRIEF SUMMARY OF THE INVENTION
The subject invention pertains to an improved air-operated hammer which can utilize a pressurized air reservoir located near a pressurized air entrance of the hammer. This pressurized air reservoir can continue to receive pressurized air even when the hammer head is falling and, preferably, can enable pressurized air to enter the hammer at a faster rate than the hammer's external compressed-air source can supply.
The subject invention can utilize a compressed-air source with a lower flow rate and/or lower pressure in comparison with a typical air-operated hammer, in order to achieve the same hammer performance. Alternatively, the subject invention can utilize an equivalent compressed-air source in comparison with a typical air-operated hammer, in order to achieve superior hammer performance, for example shorter time periods to raise the hammer head leading to move hammer drops per time.
The subject invention also relates to an automatic control valve system which can be utilized to cycle the subject hammer. The subject valve system can utilize pressurized air, for example from a compressed-air source or a pressurized-air reservoir associated with the subject hammer.
REFERENCES:
patent: 2613923 (1952-10-01), Cornett
patent: 2933068 (1960-04-01), Johnson et al.
patent: 3838741 (1974-10-01), Pepe
patent: 4086968 (1978-05-01), Wandell
patent: 4106569 (1978-08-01), Edgworth et al.
patent: 4367800 (1983-01-01), Arentsen
patent: 4377355 (1983-03-01), Chelminski
patent: 4523647 (1985-06-01), Last
Hawkins Charles L.
Tyer Robert C.
Saliwanchik Lloyd & Saliwanchik
Smith Scott A.
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