US4632191A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Steering system for percussion boring tools
Assignee: Gas Technology Institute
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Filing: 1985-04-05
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Granted: 1986-12-30
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Expires: 2005-04-05
Abstract
Abstract A steering system is disclosed for percussion boring tools for boring in the earth at an angle or in a generally horizontal direction. The steering mechanism comprises a slanted-face nose member attached to the anvil of the tool to produce a turning force on the tool and movable tail fins incorporated into the trailing end of the tool which are adapted to be selectively positioned relative to the body of the tool to negate the turning force. The fins are constructed to assume a neutral position relative to the housing of the tool when the tool is allowed to turn and to assume a spin inducing position relative to the housing of the tool to cause it to rotate when the tool is to move in a straight direction. Turning force may also be imparted to the tool by an eccentric hammer which delivers an off-axis impact to the tool anvil. For straight boring, the tail fins are fixed to induce spin of the tool about its longitudinal axis to compensate for the turning effect of the slanted nose member or eccentric hammer. When the fins are in the neutral position, the slanted nose member or the eccentric hammer will deflect the tool in a given direction. The fins also allow the nose piece to be oriented in any given plane for subsequent steering operation.
Inventors
- 👤 William J. McDonald
- 👤 Gerard T. Pittard
- 👤 William C. Maurer
- 👤 John H. Cohen
- 👤 Gregory C. Givler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:38
CPC Classifications
E; E21; E21B; E21B4/00; E21B4/06; E21B4/14; E21B4/145; E21B47/00; E21B47/02; E21B47/022; E21B47/0228; E21B7/00; E21B7/04; E21B7/06; E21B7/068; E21B7/26; E21B7/267
Claims Analysis
Total Claims: 56
Claim 1
Independent Claim
190 words
A controllable percussion tool for drilling holes in the soil comprising a cylindrical housing with a tapered front end, a first means on said front end for applying a boring force to the soil, a second means in said housing for applying a percussive force to said boring force applying means, said first and second means being cooperable to apply an asymmetric boring force, a rotatable sleeve member supported on the rear end of said housing, a pair of fins supported on said rotatable sleeve member in circumferentially spaced relation and having fixed angular positions thereon, said sleeve member and fins comprising a fin assembly, and means cooperable with at least one component of said fin assembly to establish one position permitting said fin assembly to rotate freely on said housing during movement through the earth and another position fixed in relation to said housing to cause said housing to rotate on movement through the earth, said boring means being operable to bore in a straight direction when said fin assembly is in said fixed position and to bore in a curved direction when said fin assembly is freely rotating.
Claim 2
Dependent Claim
190 words
A controllable percussion tool for drilling holes in the soil comprising a cylindrical housing with a tapered front end, a first means on said front end for applying a boring force to the soil, a second means in said housing for applying a percussive force to said boring force applying means, said first and second means being cooperable to apply an asymmetric boring force, a rotatable sleeve member supported on the rear end of said housing, a pair of fins supported on said rotatable sleeve member in circumferentially spaced relation and having fixed angular positions thereon, said sleeve member and fins comprising a fin assembly, and means cooperable with at least one component of said fin assembly to establish one position permitting said fin assembly to rotate freely on said housing during movement through the earth and another position fixed in relation to said housing to cause said housing to rotate on movement through the earth, said boring means being operable to bore in a straight direction when said fin assembly is in said fixed position and to bore in a curved direction when said fin assembly is freely rotating.
Claim 3
Dependent Claim
53 words
A controllable percussion tool according to claim 1 in which said first means comprises an anvil having a striking surface inside said housing and a boring surface outside said housing, and said second means comprises a reciprocally movable hammer positioned in said housing to apply a percussive force to said anvil striking surface.
Claim 4
Dependent Claim
33 words
A controllable percussion tool according to claim 2 in which said anvil boring surface comprises a cylindrical nose portion having a side face extending longitudinally from the tip at an acute angle thereto.
Claim 5
Dependent Claim
27 words
A controllable percussion tool according to claim 3 in which said external anvil boring surface comprises a cylindrical body and said nose portion is removably secured thereon.
Claim 6
Dependent Claim
25 words
A controllable percussion tool according to claim 2 in which said hammer member has an asymmetric end portion for applying said asymmetric earth boring force.
Claim 7
Dependent Claim
48 words
A controllable percussion tool according to claim 2 in which said hammer member has a cylindrical body portion and an end portion asymmetric to the anvil end of said anvil member for applying a hammer blow adjacent to the periphery thereof for applying said asymmetric earth boring force.
Claim 8
Dependent Claim
223 words
A controllable percussion tool for drilling holes in the soil comprising a hollow cylindrical housing with a tapered front end, a first means on said front end for applying a boring force to the soil comprising an anvil having a striking surface inside said housing and a boring surface outside said housing comprising a cylindrical nose portion having a side face extending longitudinally from the tip at an acute angle thereto, said anvil and nose portion being secured in a fixed non-rotatable position in said housing whereby movement of said tool through the soil is deviated from a straight path by reaction of said angled side face against the soil, a second means comprising a reciprocally movable hammer positioned in said housing to apply a percussive force to said anvil striking surface for transmitting a percussive force to said boring force applying means, a plurality of guide fins positioned on the exterior of said housing at the rear end thereof and having a first position permitting non-rotative movement through the soil and a second position causing said housing to rotate about its longitudinal axis on movement through the soil, and means for moving said fins between said first and second positions, said housing having a curved path through the soil when prevented from rotation and a substantially straight path when caused to rotate.
Claim 9
Dependent Claim
223 words
A controllable percussion tool for drilling holes in the soil comprising a hollow cylindrical housing with a tapered front end, a first means on said front end for applying a boring force to the soil comprising an anvil having a striking surface inside said housing and a boring surface outside said housing comprising a cylindrical nose portion having a side face extending longitudinally from the tip at an acute angle thereto, said anvil and nose portion being secured in a fixed non-rotatable position in said housing whereby movement of said tool through the soil is deviated from a straight path by reaction of said angled side face against the soil, a second means comprising a reciprocally movable hammer positioned in said housing to apply a percussive force to said anvil striking surface for transmitting a percussive force to said boring force applying means, a plurality of guide fins positioned on the exterior of said housing at the rear end thereof and having a first position permitting non-rotative movement through the soil and a second position causing said housing to rotate about its longitudinal axis on movement through the soil, and means for moving said fins between said first and second positions, said housing having a curved path through the soil when prevented from rotation and a substantially straight path when caused to rotate.
Claim 10
Dependent Claim
53 words
A controllable percussion tool according to claim 7 in which said first means comprises an anvil having a striking surface inside said housing and a boring surface outside said housing, and said second means comprises a reciprocally movable hammer positioned in said housing to apply a percussive force to said anvil striking surface.
Claim 11
Dependent Claim
33 words
A controllable percussion tool according to claim 8 in which said anvil boring surface comprises a cylindrical nose portion having a side face extending longitudinally from the tip at an acute angle thereto.
Claim 12
Dependent Claim
27 words
A controllable percussion tool according to claim 8 in which said external anvil boring surface comprises a cylindrical body and said nose portion is removably secured thereon.
Claim 13
Dependent Claim
25 words
A controllable percussion tool according to claim 8 in which said hammer member has an asymmetric end portion for applying said asymmetric earth boring force.
Claim 14
Dependent Claim
48 words
A controllable percussion tool according to claim 8 in which said hammer member has a cylindrical body portion and an end portion asymmetric to the anvil end of said anvil member for applying a hammer blow adjacent to the periphery thereof for applying said asymmetric earth boring force.
Claim 15
Dependent Claim
29 words
A controllable percussion tool according to claim 8 in which said hammer is fluid actuated, and said housing has conduit means for connection to a source of actuating fluid.
Claim 16
Dependent Claim
24 words
A controllable percussion tool according to claim 13 in which said source of actuating fluid comprises a source of compressed air for pneumatic operation.
Claim 17
Dependent Claim
23 words
A controllable percussion tool according to claim 13 in which said source of actuating fluid comprises a source of hydraulic fluid under pressure.
Claim 18
Dependent Claim
136 words
A controllable percussion tool according to claim 7 in which a rotatable sleeve member is supported on the rear end of said housing, said fins being supported on said rotatable sleeve member in circumferentially spaced relation and having fixed angular positions thereon, said sleeve member and fins comprising a fin assembly, and means cooperable with at least one component of said fin assembly to establish one position permitting said fin assembly to rotate freely on said housing during movement through the earth and another position fixed in relation to said housing to cause said housing to rotate on movement through the earth, said boring means being operable to bore in a straight direction when said fin assembly is in said fixed position and to bore in a curved direction when said fin assembly is freely rotating.
Claim 19
Dependent Claim
98 words
A controllable percussion tool according to claim 16 in which said rear end of said housing includes a supporting sleeve portion, said rotatable sleeve member being supported on said supporting sleeve portion for rotary movement thereon, clutch means operatively interconnecting said rotatable sleeve member and said supporting sleeve portion and having a first disengaged position permitting rotation of said rotatable sleeve relative to said supporting sleeve portion and a second engaged position securing said rotatable sleeve and said supporting sleeve portion for rotation together, and means to move said clutch means to said engaged and said disengaged positions.
Claim 20
Dependent Claim
159 words
A controllable percussion tool according to claim 16 in which said rear end of said housing includes a supporting sleeve portion, said rotatable sleeve member being supported on said supporting sleeve portion for rotary movement thereon and a longitudinally fixed position, clutch means having a first part operatively secured on said rotatable sleeve member and movable therewith, a second part operatively secured on said supporting sleeve portion, and a third part movable into and out of engagement with said first and second parts, said clutch means third part having a first position disengaged from said first and second parts to permit rotation of said rotatable sleeve relative to said supporting sleeve portion and a second position engaged with said first and second parts to secure said rotatable sleeve and said supporting sleeve portion for rotation together, and means to move said third part longitudinally in relation to said first and second parts to said engaged and said disengaged positions.
Claim 21
Dependent Claim
53 words
A controllable percussion tool according to claim 18 in which said third part comprises a sleeve member slidably movable of said supporting sleeve portion and within said rotatable sleeve member and having drive surfaces operatively engagable with said rotatable sleeve member and said supporting sleeve portion to secure the same for movement together.
Claim 22
Dependent Claim
35 words
A controllable percussion tool according to claim 19 in which said slidable sleeve member is movable between a position engaged with and a position disengaged from said rotatable sleeve member and said supporting sleeve portion.
Claim 23
Dependent Claim
85 words
A controllable percussion tool according to claim 19 in which said slidable sleeve member is secured on said supporting sleeve member for rotation therewith, said rotatable sleeve member and said slidable sleeve member have at least one recess on one and one projection on the other cooperable when engaged to secure said rotatable sleeve member and said supporting sleeve member together for rotation together, and said slidable sleeve member is movable between a position engaged with and a position disengaged from said rotatable sleeve member.
Claim 24
Dependent Claim
135 words
A controllable percussion tool according to claim 16 in which said rear end of said housing includes a supporting sleeve portion, said rotatable sleeve member being supported on said supporting sleeve portion for rotary movement thereon and having a predetermined amount of longitudinal movement, clutch means having one part operatively secured on said rotatable sleeve member and movable therewith and another part operatively secured on said supporting sleeve portion, said clutch means parts having a first disengaged position permitting rotation of said rotatable sleeve relative to said supporting sleeve portion and a second engaged position securing said rotatable sleeve and said supporting sleeve portion for rotation together, and means to move said rotatable sleeve longitudinally in relation to said supporting sleeve portion to move said clutch means parts to said engaged and said disengaged positions.
Claim 25
Dependent Claim
39 words
A controllable percussion tool according to claim 22 in which said clutch means parts comprises drive teeth on said rotatable sleeve and said supporting sleeve portion respectively, and means for moving said drive teeth into and out of engagement.
Claim 26
Dependent Claim
20 words
A controllable percussion tool according to claim 23 in which said drive teeth are positioned for end to end engagement.
Claim 27
Dependent Claim
46 words
A controllable percussion tool according to claim 23 in which said drive teeth are on the inside of said rotatable sleeve and the outside of said supporting sleeve portion respectively, and means for moving at least one of said sleeves to engage and disengage said teeth.
Claim 28
Dependent Claim
54 words
A controllable percussion tool according to claim 22 in which said clutch means parts comprises drive teeth on one of said sleeves and a drive member on the other sleeve and relatively movable into and out of engagement therewith, and means for moving said drive teeth and drive member into and out of engagement.
Claim 29
Dependent Claim
17 words
A controllable percussion tool according to claim 26 in which said drive member comprises a drive pin.
Claim 30
Dependent Claim
55 words
A controllable percussion tool according to claim 22 in which said clutch means parts comprises a drive slot on one of said sleeves and a drive member on the other sleeve and relatively movable into and out of engagement therewith, and means for moving said drive slot and drive member into and out of engagement.
Claim 31
Dependent Claim
17 words
A controllable percussion tool according to claim 27 in which said drive member comprises a drive pin.
Claim 32
Dependent Claim
55 words
A controllable percussion tool according to claim 22 in which said clutch means parts comprises a drive slot on one of said sleeves and a drive spline on the other sleeve and relatively movable into and out of engagement therewith, and means for moving said drive slot and drive spline into and out of engagement.
Claim 33
Dependent Claim
121 words
A controllable percussion tool according to claim 7 in which a fixed supporting sleeve member is supported on the rear end of said housing, said fins being pivotally supported on said sleeve member in circumferentially spaced relation thereon, said fins each having a first position parallel to the longitudinal axis of said housing and a second position extending at an acute angle to the longitudinal axis of said housing, means cooperable with said fins to move the same to said first position or said second position, and said boring means being operable to bore in a straight direction when said fins are in said second position and to bore in a curved direction when said fins are in said first position.
Claim 34
Dependent Claim
104 words
A controllable percussion tool according to claim 31 in which said rear end of said housing includes a supporting sleeve portion, said fixed sleeve member being supported on said supporting sleeve portion, supporting pins for each of said fins extending into the space between said supporting sleeve portion and said fixed sleeve member and having operating means thereon, an operating member slidable on said supporting sleeve portion and engagable with said fin operating means, and means to move said operating member longitudinally in relation to said fin operating means to move the same to position said fins in said parallel or said angled position.
Claim 35
Dependent Claim
70 words
A controllable percussion tool according to claim 32 in which said pin operating means comprises a rotary member secured on each of said supporting pins, said operating member comprises a slidably movable sleeve, said pin-operating rotary member and said drive sleeve having a recess in one and a projecting drive member on the other cooperable for rotating each of said fin members upon sliding movement of said slidably movable sleeve.
Claim 36
Dependent Claim
251 words
A controllable percussion tool for drilling holes in the soil comprising a hollow cylindrical housing with a tapered front end, a first means on said front end for applying a boring force to the soil comprising an anvil having a striking surface inside said housing and a boring surface outside said housing comprising a cylindrical nose portion having a side face extending longitudinally from the tip at an acute angle thereto, said anvil and nose portion being secured in a fixed non-rotatable position in said housing whereby movement of said tool through the soil is deviated from a straight path by reaction of said angled side face against the soil, a second means comprising a reciprocally movable hammer positioned in said housing to apply a percussive force to said anvil striking surface for transmitting a percussive force to said boring force applying means, means for connecting said hammer to an external energy supplying means, a plurality of guide fins positioned on the exterior of said housing at the rear end thereof and having a first position permitting non-rotative movement through the soil and a second position with the fins fixed relative to said housing at an angle causing said housing to rotate about its longitudinal axis on movement through the soil, and externally operated means for moving said fins between said first and second positions, whereby said tool has a curved path through the soil when said housing is prevented from rotation and a substantially straight path when caused to rotate.
Claim 37
Dependent Claim
251 words
A controllable percussion tool for drilling holes in the soil comprising a hollow cylindrical housing with a tapered front end, a first means on said front end for applying a boring force to the soil comprising an anvil having a striking surface inside said housing and a boring surface outside said housing comprising a cylindrical nose portion having a side face extending longitudinally from the tip at an acute angle thereto, said anvil and nose portion being secured in a fixed non-rotatable position in said housing whereby movement of said tool through the soil is deviated from a straight path by reaction of said angled side face against the soil, a second means comprising a reciprocally movable hammer positioned in said housing to apply a percussive force to said anvil striking surface for transmitting a percussive force to said boring force applying means, means for connecting said hammer to an external energy supplying means, a plurality of guide fins positioned on the exterior of said housing at the rear end thereof and having a first position permitting non-rotative movement through the soil and a second position with the fins fixed relative to said housing at an angle causing said housing to rotate about its longitudinal axis on movement through the soil, and externally operated means for moving said fins between said first and second positions, whereby said tool has a curved path through the soil when said housing is prevented from rotation and a substantially straight path when caused to rotate.
Claim 38
Dependent Claim
30 words
A controllable percussion tool according to claim 34 in which said hammer is fluid actuated, and said connecting means comprises conduit means for connection to a source of actuating fluid.
Claim 39
Dependent Claim
24 words
A controllable percussion tool according to claim 35 in which said source of actuating fluid comprises a source of compressed air for pneumatic operation.
Claim 40
Dependent Claim
23 words
A controllable percussion tool according to claim 35 in which said source of actuating fluid comprises a source of hydraulic fluid under pressure.
Claim 41
Dependent Claim
40 words
A controllable percussion tool according to claim 34 in which said anvil member and said hammer member comprise earth boring means, and at least one member of said earth boring means including means for producing an asymmetric earth boring force.
Claim 42
Dependent Claim
33 words
A controllable percussion tool according to claim 38 in which said percussion operated tip comprises a cylindrical nose portion having a side face extending longitudinally from the tip at an acute angle thereto.
Claim 43
Dependent Claim
26 words
A controllable percussion tool according to claim 39 in which said percussion operated tip comprises a cylindrical body and said nose portion is removably secured thereon.
Claim 44
Dependent Claim
25 words
A controllable percussion tool according to claim 38 in which said hammer member has an asymmetric end portion for applying said asymmetric earth boring force.
Claim 45
Dependent Claim
48 words
A controllable percussion tool according to claim 38 in which said hammer member has a cylindrical body portion and an end portion asymmetric to the anvil end of said anvil member for applying a hammer blow adjacent to the periphery thereof for applying said asymmetric earth boring force.
Claim 46
Dependent Claim
136 words
A controllable percussion tool according to claim 38 in which a rotatable sleeve member is supported on the rear end of said housing, said fins being supported on said rotatable sleeve member in circumferentially spaced relation and having fixed angular positions thereon, said sleeve member and fins comprising a fin assembly, and means cooperable with at least one component of said fin assembly to establish one position permitting said fin assembly to rotate freely on said housing during movement through the earth and another position fixed in relation to said housing to cause said housing to rotate on movement through the earth, said boring means being operable to bore in a straight direction when said fin assembly is in said fixed position and to bore in a curved direction when said fin assembly is freely rotating.
Claim 47
Dependent Claim
98 words
A controllable percussion tool according to claim 43 in which said rear end of said housing includes a supporting sleeve portion, said rotatable sleeve member being supported on said supporting sleeve portion for rotary movement thereon, clutch means operatively interconnecting said rotatable sleeve member and said supporting sleeve portion and having a first disengaged position permitting rotation of said rotatable sleeve relative to said supporting sleeve portion and a second engaged position securing said rotatable sleeve and said supporting sleeve portion for rotation together, and means to move said clutch means to said engaged and said disengaged positions.
Claim 48
Dependent Claim
159 words
A controllable percussion tool according to claim 43 in which said rear end of said housing includes a supporting sleeve portion, said rotatable sleeve member being supported on said supporting sleeve portion for rotary movement thereon and a longitudinally fixed position, clutch means having a first part operatively secured on said rotatable sleeve member and movable therewith, a second part operatively secured on said supporting sleeve portion, and a third part movable into and out of engagement with said first and second parts, said clutch means third part having a first position disengaged from said first and second parts to permit rotation of said rotatable sleeve relative to said supporting sleeve portion and a second position engaged with said first and second parts to secure said rotatable sleeve and said supporting sleeve portion for rotation together, and means to move said third part longitudinally in relation to said first and second parts to said engaged and said disengaged positions.
Claim 49
Dependent Claim
135 words
A controllable percussion tool according to claim 43 in which said rear end of said housing includes a supporting sleeve portion, said rotatable sleeve member being supported on said supporting sleeve portion for rotary movement thereon and having a predetermined amount of longitudinal movement, clutch means having one part operatively secured on said rotatable sleeve member and movable therewith and another part operatively secured on said supporting sleeve portion, said clutch means parts having a first disengaged position permitting rotation of said rotatable sleeve relative to said supporting sleeve portion and a second engaged position securing said rotatable sleeve and said supporting sleeve portion for rotation together, and means to move said rotatable sleeve longitudinally in relation to said supporting sleeve portion to move said clutch means parts to said engaged and said disengaged positions.
Claim 50
Dependent Claim
121 words
A controllable percussion tool according to claim 38 in which a fixed supporting sleeve member is supported on the rear end of said housing, said fins being pivotally supported on said sleeve member in circumferentially spaced relation thereon, said fins each having a first position parallel to the longitudinal axis of said housing and a second position extending at an acute angle to the longitudinal axis of said housing, means cooperable with said fins to move the same to said first position or said second position, and said boring means being operable to bore in a straight direction when said fins are in said second position and to bore in a curved direction when said fins are in said first position.
Claim 51
Dependent Claim
104 words
A controllable percussion tool according to claim 47 in which said rear end of said housing includes a supporting sleeve portion, said fixed sleeve member being supported on said supporting sleeve portion, supporting pins for each of said fins extending into the space between said supporting sleeve portion and said fixed sleeve member and having operating means thereon, an operating member slidable on said supporting sleeve portion and engagable with said fin operating means, and means to move said operating member longitudinally in relation to said fin operating means to move the same to position said fins in said parallel or said angled position.
Claim 52
Dependent Claim
64 words
A controllable percussion tool according to claim 48 in which said pin operating means comprises a rotary member secured on each of said supporting pins and having a drive recess therein, and said operating member comprises a slidably movable sleeve having a drive member cooperable with said drive recess for rotating each of said fin members upon sliding movement of said slidably movable sleeve.
Claim 53
Dependent Claim
207 words
A controllable percussion tool for drilling holes in the soil comprising a cylindrical housing with a tapered front end, a first means on said front end for applying a boring force to the soil comprising an anvil having a striking surface inside said housing and a boring surface outside said housing comprising a cylindrical nose portion having a side face extending longitudinally from the tip at an acute angle thereto, said anvil and nose portion being secured in a fixed non-rotatable position in said housing whereby movement of said tool through the soil is deviated from a straight path by reaction of said angled side face against the soil, a second means comprising a reciprocally movable hammer positioned in said housing to apply a percussive force to said anvil striking surface for transmitting a percussive force to said boring force applying means, at least one guide fin positioned on the exterior of said housing at the rear end thereof having one position preventing rotary motion of said housing about its longitudinal axis and another position permitting rotary motion of said housing about its longitudinal axis, said housing having a curved path through the soil when prevented from rotation and a substantially straight path when permitted to rotate.
Claim 54
Dependent Claim
207 words
A controllable percussion tool for drilling holes in the soil comprising a cylindrical housing with a tapered front end, a first means on said front end for applying a boring force to the soil comprising an anvil having a striking surface inside said housing and a boring surface outside said housing comprising a cylindrical nose portion having a side face extending longitudinally from the tip at an acute angle thereto, said anvil and nose portion being secured in a fixed non-rotatable position in said housing whereby movement of said tool through the soil is deviated from a straight path by reaction of said angled side face against the soil, a second means comprising a reciprocally movable hammer positioned in said housing to apply a percussive force to said anvil striking surface for transmitting a percussive force to said boring force applying means, at least one guide fin positioned on the exterior of said housing at the rear end thereof having one position preventing rotary motion of said housing about its longitudinal axis and another position permitting rotary motion of said housing about its longitudinal axis, said housing having a curved path through the soil when prevented from rotation and a substantially straight path when permitted to rotate.
Claim 55
Dependent Claim
191 words
A controllable percussion tool for drilling holes in the soil comprising a hollow cylindrical housing with a tapered front end, a first means on said front end for applying a boring force to the soil, a second means in said housing for applying a percussive force to said boring force applying means, said first and second means being cooperable to apply an asymmetric boring force, a rotatable sleeve member supported on the rear end of said housing, a pair of fins supported on said rotatable sleeve member in circumferentially spaced relation and having fixed angular positions thereon, said sleeve member and fins comprising a fin assembly, and means cooperable with at least one component of said fin assembly to establish one position permitting said fin assembly to rotate freely on said housing during movement through the earth and another position fixed in relation to said housing to cause said housing to rotate on movement through the earth, said boring means being operable to bore in a straight direction when said fin assembly is in said fixed position and to bore in a curved direction when said fin assembly is freely rotating.
Claim 56
Dependent Claim
191 words
A controllable percussion tool for drilling holes in the soil comprising a hollow cylindrical housing with a tapered front end, a first means on said front end for applying a boring force to the soil, a second means in said housing for applying a percussive force to said boring force applying means, said first and second means being cooperable to apply an asymmetric boring force, a rotatable sleeve member supported on the rear end of said housing, a pair of fins supported on said rotatable sleeve member in circumferentially spaced relation and having fixed angular positions thereon, said sleeve member and fins comprising a fin assembly, and means cooperable with at least one component of said fin assembly to establish one position permitting said fin assembly to rotate freely on said housing during movement through the earth and another position fixed in relation to said housing to cause said housing to rotate on movement through the earth, said boring means being operable to bore in a straight direction when said fin assembly is in said fixed position and to bore in a curved direction when said fin assembly is freely rotating.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-12-29 | 1990-06-30 | 1990-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-29 | 1994-06-30 | 1994-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-29 | 1998-06-30 | 1998-12-30 | $7700.00 | Window Closed / Lapsed |