US3727700A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pneumatically percussive tool having a vibration free handle
Assignee: Chicago Pneumatic Tool Co LLC
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Filing: 1971-04-19
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Granted: 1973-04-17
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Expires: 1991-04-19
Abstract
Abstract A pneumatically percussive tool having a handle isolated from the body of the tool so that vibrations of a reciprocating hammer in the body are not transmitted to the handle. This is accomplished by arranging the handle in axial slidable relation to the body so as to permit the body to vibrate relative to the handle; and by maintaining a cushion of pressurized air in a chamber between the handle and the body which chamber is connected with a pressure air source and with a relief check valve. The pressure developing in the chamber is determined by a spring load on the check valve, which load varies automatically with the pressure exerted by the operator in holding the tool pressed against the work. The pressurized air cushion constantly counterbalances the opposing force exerted by the operator so that the body of the tool is maintained at all times in spaced relation to the handle as it vibrates. A pair of air feed ports to the hammer are adapted to be brought into or out of register with each other accordingly as the tool is pressed against or removed from the work.
Inventors
- 👤 L Amtsberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 03:13
CPC Classifications
B; B25; B25D; B25D17/00; B25D17/24; B25D17/245
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
223 words
In a pneumatically percussive tool including a cylinder having a hammer pneumatically reciprocable therein to repeatedly pound a work element carried in a front end of the cylinder, and including a handle separable from the cylinder adapted to be held by the operator, a backhead closing over the rear of the cylinder having a portion raised above the level of the cylinder, a shaft rigid with the handle slidably received through a bore in the raised portion of the backhead and extending axially beyond a forward end of the backhead, a stop ring on a forward end of the shaft preventing slidable escape of the backhead from the shaft, a throttle controlled pressure air inlet feed passage extending through the handle into the shaft having connection with a side port in the shaft, an air distributing valve in the backhead having response to pressure air fed to it to direct the air alternately to opposite ends of the hammer, a valve feed passage through the backhead communicating with the air distributing valve, the backhead having a forwardly moved position on the shaft wherein the valve feed passage is located in unregistered relation to the side port, and the backhead having a position displaced away from the stop toward the handle in which position the valve feed passage is registered with the side port.
Claim 2
Dependent Claim
223 words
In a pneumatically percussive tool including a cylinder having a hammer pneumatically reciprocable therein to repeatedly pound a work element carried in a front end of the cylinder, and including a handle separable from the cylinder adapted to be held by the operator, a backhead closing over the rear of the cylinder having a portion raised above the level of the cylinder, a shaft rigid with the handle slidably received through a bore in the raised portion of the backhead and extending axially beyond a forward end of the backhead, a stop ring on a forward end of the shaft preventing slidable escape of the backhead from the shaft, a throttle controlled pressure air inlet feed passage extending through the handle into the shaft having connection with a side port in the shaft, an air distributing valve in the backhead having response to pressure air fed to it to direct the air alternately to opposite ends of the hammer, a valve feed passage through the backhead communicating with the air distributing valve, the backhead having a forwardly moved position on the shaft wherein the valve feed passage is located in unregistered relation to the side port, and the backhead having a position displaced away from the stop toward the handle in which position the valve feed passage is registered with the side port.
Claim 3
Dependent Claim
33 words
In a pneumatically percussive tool as in claim 1, wherein the backhead has a piston extending axially from its rear into a piston chamber in the handle in parallel relation to the shaft.
Claim 4
Dependent Claim
90 words
In a pneumatically percussive tool as in claim 2, wherein a chamber of larger volume than the piston chamber is formed in the handle in coaxial relation to the piston chamber, restricted passage means is provided connecting both the piston chamber and the larger volume chamber with the air inlet passage, and the larger volume chamber is connected with a relief passage having a normally closed spring loaded check valve, the spring being loaded in parallel relation to the shaft between the check valve and the rear of the backhead.
Claim 5
Dependent Claim
49 words
In a pneumatically percussive tool as in claim 3, wherein an annular groove is formed in the handle coaxial with the piston chamber and has a vent connection, a diaphragm seals the groove from the larger volume chamber and normally blocks communication of the piston chamber with the groove.
Claim 6
Dependent Claim
156 words
In a pneumatically percussive tool including a cylinder having a hammer pneumatically reciprocable therein to repeatedly pound a work element carried in a front end of the cylinder, and including a handle to be held by the operator; a shaft rigid with the handle supporting the cylinder for limited axial sliding movement of the cylinder along the shaft relative to the handle, a piston extending axially rearwardly from a rear face of the cylinder, a piston chamber in the handle in which the piston is received, the piston being adapted to be retracted into the piston chamber and the cylinder adapted to be moved along the shaft toward the handle upon the operator applying the work element to a hard stationary surface and exerting a forwardly pressing force upon the handle, and means for exerting upon the piston a pneumatic force substantially counterbalancing the pressing force that might be applied by the operator to the handle.
Claim 7
Dependent Claim
156 words
In a pneumatically percussive tool including a cylinder having a hammer pneumatically reciprocable therein to repeatedly pound a work element carried in a front end of the cylinder, and including a handle to be held by the operator; a shaft rigid with the handle supporting the cylinder for limited axial sliding movement of the cylinder along the shaft relative to the handle, a piston extending axially rearwardly from a rear face of the cylinder, a piston chamber in the handle in which the piston is received, the piston being adapted to be retracted into the piston chamber and the cylinder adapted to be moved along the shaft toward the handle upon the operator applying the work element to a hard stationary surface and exerting a forwardly pressing force upon the handle, and means for exerting upon the piston a pneumatic force substantially counterbalancing the pressing force that might be applied by the operator to the handle.
Claim 8
Dependent Claim
31 words
In a pneumatically percussive tool as in claim 5, wherein means is provided for automatically varying the counterbalancing pneumatic force accordingly as the pressing force applied by the operator is varied.
Claim 9
Dependent Claim
42 words
In a pneumatically percussive tool as in claim 6, wherein a spring is loaded between the check valve and an opposed face of the cylinder and is disposed in parallel relation to the axis of the shaft and that of the cylinder.
Claim 10
Dependent Claim
42 words
In a pneumatically percussive tool as in claim 6, wherein manipulative air feed control means is provided for feeding from a common source pressure air concurrently to the cylinder to recipRocate the hammer, and to the piston chamber rearwardly of the piston.
Claim 11
Dependent Claim
35 words
In a pneumatically percussive tool as in claim 6, wherein control means is provided for feeding pressure air concurrently to the cylinder to reciprocate the hammer, and to the piston chamber rearwardly of the piston.
Claim 12
Dependent Claim
211 words
In a pneumatically percussive tool as in claim 9, wherein a pressure air chamber of larger volume than the piston chamber is formed in the handle in opposed aligned and coaxial relation to the piston chamber, the pressure air chamber is connected with a vent passage, a spring loaded check valve in the vent passage blocks escape of air from the pressure air chamber, means is provided for automatically varying the spring load accordingly as the cylinder is moved axially relative to the handle, a groove is formed in the handle coaxially with the piston chamber and facing the pressure air chamber, the groove is connected with a vent and is separated from the piston chamber by means of an annular shoulder, a diaphragm seals the groove off from the pressure air chamber and is seated under pressure of air in the pressure air chamber upon the annular shoulder so as to normally block communication of the piston chamber with the groove, a restricted passage means is connected with the control means for flow of pressure air to the piston chamber, and a separate similar restricted passage is connected with the control means for flow of pressure air to the pressure air chamber concurrently with the flow to the piston chamber.
Claim 13
Dependent Claim
72 words
In a pneumatically percussive tool as in claim 9, wherein a pressure chamber of larger volume than the piston chamber is formed in the handle in opposed aligned and coaxial relation to the piston chamber and in direct communication with the latter, the pressure chamber being connected with a vent passage, and there being a spring loaded check valve in the vent passage normally blocking escape of air from the pressure chamber.
Claim 14
Dependent Claim
48 words
In a pneumatically percussive tool as in claim 11, wherein the spring load on the check valve determines the degree of pressure development in the pressure chamber, and means is provided for automatically varying the spring load accordingly as the cylinder is moved axially relative to the handle.
Claim 15
Dependent Claim
138 words
In a pneumatically percussive tool including a cylinder body having a hammer pneumatically reciprocable therein to repeatedly pound a work element carried in a front end of the body, and including a handle to be held by the operator; a shaft rigid with the handle supporting the body for limited axial sliding movement of the body relative to the handle, a piston extending axially from a rear face of the body received in a piston chamber provided in the handle, means for continuously exerting a pneumatic force upon the piston biasing it outwardly of the piston chamber, and stop means limiting the extent of movement of the body away from the handle as a consequence of the biasing force upon the piston so that the piston remains at all times at least in part within the piston chamber.
Claim 16
Dependent Claim
138 words
In a pneumatically percussive tool including a cylinder body having a hammer pneumatically reciprocable therein to repeatedly pound a work element carried in a front end of the body, and including a handle to be held by the operator; a shaft rigid with the handle supporting the body for limited axial sliding movement of the body relative to the handle, a piston extending axially from a rear face of the body received in a piston chamber provided in the handle, means for continuously exerting a pneumatic force upon the piston biasing it outwardly of the piston chamber, and stop means limiting the extent of movement of the body away from the handle as a consequence of the biasing force upon the piston so that the piston remains at all times at least in part within the piston chamber.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-16 | 1976-10-16 | 1977-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-16 | 1980-10-16 | 1981-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-16 | 1984-10-16 | 1985-04-17 | $7700.00 | Window Closed / Lapsed |