Pneumatic ground piercing tool
First Claim
1. A ground piercing tool, comprisingan elongated tubular tool housing, including a front anvil having a lengthwise bore therein;
- a striker disposed for reciprocation within an internal chamber of the housing to impart impacts to an impact surface of the anvil for driving the tool forwardly through the ground;
a chisel including a front head and a rearwardly extending chisel shaft slidably disposed in the bore of the anvil, which chisel is movable between a rearwardmost position at which a rear end portion of the chisel shaft protrudes from the bore of the anvil to receive an initial impact from the striker, and a forwardmost position at which the striker impacts on a rear impact surface of the anvil; and
a distributing mechanism that reciprocates the striker in response to a supply of compressed fluid, wherein the housing and chisel shaft cooperate to define a front chamber that decreases in volume as the chisel moves forward relative to the housing, and the distributing mechanism includes passages that conduct compressed fluid to the front chamber, which front chamber is configured to form a gas spring using such compressed fluid.
4 Assignments
0 Petitions
Accused Products
Abstract
A ground piecing tool includes a housing and an air distributing mechanism that reciprocates a striker to impact a chisel shaft in response to a supply of compressed fluid including a fluid inlet tube mounted in the bore of the striker having a radial port, a rear end of the inlet tube being in communication with the distributing mechanism, wherein the housing and chisel shaft cooperate to define a front chamber that decreases in volume as the chisel moves forward relative to the housing, and wherein the chisel shaft has a radial passage therein that conducts compressed fluid from the radial port of the inlet tube to the front chamber, which is configured to form an air spring.
22 Citations
18 Claims
-
1. A ground piercing tool, comprising
an elongated tubular tool housing, including a front anvil having a lengthwise bore therein; -
a striker disposed for reciprocation within an internal chamber of the housing to impart impacts to an impact surface of the anvil for driving the tool forwardly through the ground; a chisel including a front head and a rearwardly extending chisel shaft slidably disposed in the bore of the anvil, which chisel is movable between a rearwardmost position at which a rear end portion of the chisel shaft protrudes from the bore of the anvil to receive an initial impact from the striker, and a forwardmost position at which the striker impacts on a rear impact surface of the anvil; and a distributing mechanism that reciprocates the striker in response to a supply of compressed fluid, wherein the housing and chisel shaft cooperate to define a front chamber that decreases in volume as the chisel moves forward relative to the housing, and the distributing mechanism includes passages that conduct compressed fluid to the front chamber, which front chamber is configured to form a gas spring using such compressed fluid. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A ground piercing tool, comprising:
-
an elongated tubular tool housing, including a front anvil having a lengthwise bore therein; a striker disposed for reciprocation within an internal chamber of the housing to impart impacts to an impact surface of the anvil for driving the tool forwardly through the ground, the striker having a lengthwise, frontwardly opening central bore therein coaxial with the bore of the anvil; a chisel including a front head and a rearwardly extending chisel shaft slidably disposed in the bore of the anvil, which chisel is movable between a rearwardmost position at which a rear end portion of the chisel shaft protrudes from the bore of the anvil to receive an initial impact from the striker, and a forwardmost position at which the striker impacts on a rear impact surface of the anvil; and a distributing mechanism that reciprocates the striker in response to a supply of compressed fluid, including a fluid inlet tube mounted in the bores of the anvil and striker having a radial port, a rear end of the inlet tube being in communication with the distributing mechanism, wherein the housing and chisel shaft cooperate to define a front chamber that decreases in volume as the chisel moves forward relative to the housing, and the chisel shaft has a radial passage therein that conducts compressed fluid from the radial port of the inlet tube to the front chamber, which front chamber is configured to form a gas spring using such compressed fluid. - View Dependent Claims (13, 14)
-
-
15. A ground piercing tool, comprising
an elongated tubular tool housing, including a front anvil having a lengthwise bore therein; -
a striker disposed for reciprocation within an internal chamber of the housing to impart impacts to an impact surface of the anvil for driving the tool forwardly through the ground; a chisel including a front head, a chisel shaft extending rearwardly from the head, which chisel shaft is slidably disposed in the bore of the anvil and is movable between a rearwardmost position at which a rear end portion of the chisel shaft protrudes from the bore of the anvil to receive an initial impact from the striker, and a forwardmost position at which the striker impacts on a rear impact surface of the anvil, and a tubular bushing in which a midportion of the chisel shaft is slidably mounted, the bushing having a rearwardly extending threaded external portion that is threadedly engaged with internal threads in the bore of the anvil in order to secure the chisel to the anvil; a jamb nut mounted on the threaded external portion of the bushing in front of the anvil, which jamb nut can be tightened against the anvil to apply a clamp load to the threaded connection between the bushing and the anvil; and a distributing mechanism that reciprocates the striker in response to a supply of compressed fluid, wherein the housing and chisel shaft cooperate to define a front chamber that decreases in volume as the chisel moves forward relative to the housing, and the distributing mechanism includes passages that conduct compressed fluid to the front chamber, which front chamber is configured to form an gas spring using such compressed fluid.
-
-
16. A ground piercing tool, comprising:
-
an elongated tubular tool housing, including a front anvil having a lengthwise bore therein; a striker disposed for reciprocation within an internal chamber of the housing to impart impacts to an impact surface of the anvil for driving the tool forwardly through the ground; a distributing mechanism that reciprocates the striker in response to a supply of compressed fluid; a chisel including a front head and a rearwardly extending chisel shaft slidably disposed in the bore of the anvil, which chisel is movable between a rearwardmost position at which a rear end portion of the chisel shaft protrudes from the bore of the anvil to receive an initial impact from the striker, and a forwardmost position at which the striker impacts on a rear impact surface of the anvil, wherein the chisel shaft has a radially extending shoulder, and the housing and a front surface of the shoulder of the chisel shaft cooperate to define a front chamber that decreases in volume as the chisel moves forward relative to the housing; a spring disposed in the front chamber that resists the decrease in volume of the front chamber as the chisel moves forward relative to the housing; and a passage in the housing for venting a space between a rear surface of the shoulder of the chisel shaft and the anvil. - View Dependent Claims (17, 18)
-
Specification