Trenching apparatus

Claim 2

Apparatus for digging a trench beneath a pipeline, comprising a carriage supportable on the pipeline for forward movement longitudinally therealong, a pair of arms pivotally connected to the carriage about a substantially vertical axis at least one cutter head rotatably supported by each of the arms about a generally vertical axis, means mounted on each arm for rotating the cutter head thereon, a conduit mounted on each arm to receive cuttings from the cutter head on said arm, and a suction pump connected to each conduit for depositing said cuttings to a position removed from the trench beneath the pipeline.

Claim 3

Apparatus for digging a trench beneath a pipeline, comprising a carriage supportable on the pipeline for forward movement longitudinally therealong, a pair of arms pivotally connected to the carriage about a substantially vertical axis at least one cutter head rotatably supported by each of the arms about a generally vertical axis, means mounted on each arm for rotating the cutter head thereon, a conduit mounted on each arm to receive cuttings from the cutter head on said arm, and a suction pump connected to each conduit for depositing said cuttings to a position removed from the trench beneath the pipeline.

Claim 4

Apparatus for digging a trench beneath a pipeline, comprising a carriage supportable on the pipeline for forward movement longitudinally therealong, a pair of arms pivotally connected to the carriage about a substantially vertical axis at least one cutter head rotatably supported by each of the arms about a generally vertical axis, means mounted on each arm for rotating the cutter head thereon, a conduit mounted on each arm to receive cuttings from the cutter head on said arm, and a suction pump connected to each conduit for depositing said cuttings to a position removed from the trench beneath the pipeline.

Claim 5

Apparatus of the character defined in claim 1, including a reciprocable actuator means connected to the arms for moving the cutter heads between said positions.

Claim 6

Apparatus of the character defined in claim 1, wherein each cutter comprises a cage rotatable about a substantially vertical axis, and the conduit extends within the cage.

Claim 7

Apparatus of the character defined in claim 3, including another conduit mounted on each arm behind the cage, and a suction pump connected to each of said other conduits for depositing cuttings to a position removed from the trench.

Claim 8

Apparatus of the character defined in cLaim 1, wherein each cutter comprises a cage rotatable about a substantially vertical axis, and the conduit is behind the cage to receive cuttings removed thereby.

Claim 9

Apparatus of the character defined in claim 1, wherein the axis about which each arm is swung is disposed rearwardly of said cutter head, and a wheel is mounted on the carriage for rolling along the pipeline forwardly of said axes.

Claim 10

Apparatus for digging a trench beneath a pipeline, comprising a carriage, a wheel assembly supporting the carriage for movement longitudinally forwardly along the pipeline, cutter means rotatable about a substantially vertical axis, means for supporting the cutter means from the carriage for movement therewith forwardly of said wheel assembly, a buoyancy tank mounted on the carriage with its center of buoyancy forwardly of said cutter means and wheel assembly, and at least one other buoyancy tank mounted on the carriage with its center of buoyancy rearwardly of the wheel assembly.

Claim 11

Apparatus for digging a trench beneath a pipeline, comprising a carriage, a wheel assembly supporting the carriage for movement longitudinally forwardly along the pipeline, cutter means rotatable about a substantially vertical axis, means for supporting the cutter means from the carriage for movement therewith forwardly of said wheel assembly, a buoyancy tank mounted on the carriage with its center of buoyancy forwardly of said cutter means and wheel assembly, and at least one other buoyancy tank mounted on the carriage with its center of buoyancy rearwardly of the wheel assembly.

Claim 12

Apparatus for digging a trench beneath a pipeline, comprising a carriage, a wheel assembly supporting the carriage for movement longitudinally forwardly along the pipeline, cutter means rotatable about a substantially vertical axis, and means for supporting the cutter means from the carriage for movement therewith forwardly of said wheel assembly, wherein the cutter means comprises a pair of rotatable cutter heads each connected to the carriage for swinging about a substantially vertical axis between positions in which they are at least partially beneath the pipeline and in which they are relatively widely spaced apart for movement vertically past opposite side of the pipeline.

Claim 13

Apparatus for digging a trench beneath a pipeline, comprising a carriage, a wheel assembly supporting the carriage for movement longitudinally forwardly along the pipeline, cutter means rotatable about a substantially vertical axis, and means for supporting the cutter means from the carriage for movement therewith forwardly of said wheel assembly, wherein the cutter means comprises a pair of rotatable cutter heads each connected to the carriage for swinging about a substantially vertical axis between positions in which they are at least partially beneath the pipeline and in which they are relatively widely spaced apart for movement vertically past opposite side of the pipeline.

Claim 14

Apparatus of the character defined in claim 8, wherein each cutter head is forwardly of the axis about which it swings, and said wheel assembly includes a wheel engaging the top of the pipeline intermediate each said cutter head and axis.

Claim 15

Apparatus for digging a trench beneath a pipeline, comprising a carriage, first and second wheels mounted on the carriage for engaging the top and bottom of the pipeline, respectively, means for causing said first and second wheels to engage the top and bottom of the pipeline with a constant load, means for driving at least one of said wheels so as to move the carriage along the pipeline, cutter means, and means supporting the cutter means from the carriage for movement therewith at least partially beneath the pipeline.

Claim 16

Apparatus for digging a trench beneath a pipeline, comprising a carriage, first and second wheels mounted on the carriage for engaging the top and bottom of the pipeline, respectively, means for causing said first and second wheels to engage the top and bottom of the pipeline with a constant load, means for driving at least one of said wheels so as to move the carriage along the pipeline, cutter means, and means supporting the cutter means from the carriage for movement therewith at least partially beneath the pipeline.

Claim 17

Apparatus of the character defined in claim 10, including at least one buoyancy tank mounted on the carriage for movement therewith.

Claim 18

Apparatus of the character defined in claim 10, including means connecting the second wheel to the carriage for movement between said position engaging the bottom of the pipeline and another position to permit said carriage to be moved to and from a position in which said first wheel is supported on the pipeline.

Claim 19

Apparatus of the character defined in claim 12, wherein the second wheel connecting means comprises a first arm pivotally connected to the carriage for swinging laterally about a horizontal axis generally parallel to the pipeline, a second arm pivotally connected to the first arm for swinging about an axis perpendicular to said horizontal axis, and means for selectively causing each of said arms to swing about its respective axis.

Claim 20

Apparatus of the character defined in claim 10, including rollers carried by the carriage for disposal at least close to the top, bottom and opposite sides of the pipeline forwardly and rearwardly of said wheels.

Claim 21

Apparatus for digging a trench beneath a pipeline, comprising a carriage, a pair of wheels mounted on the carriage for engaging the top of the pipeline at longitudinally spaced apart locations therealong, a third wheel mounted on the carriage for engaging the bottom of the pipeline intermediate the pair of wheels, means for causing the wheels to engage said pipeline with a constant load, means for driving at least one of said wheels so as to move The carriage along the pipeline, cutter means, and means supporting the cutter means from the carriage for movement therewith.

Claim 22

Apparatus for digging a trench beneath a pipeline, comprising a carriage, a pair of wheels mounted on the carriage for engaging the top of the pipeline at longitudinally spaced apart locations therealong, a third wheel mounted on the carriage for engaging the bottom of the pipeline intermediate the pair of wheels, means for causing the wheels to engage said pipeline with a constant load, means for driving at least one of said wheels so as to move The carriage along the pipeline, cutter means, and means supporting the cutter means from the carriage for movement therewith.

Claim 23

Apparatus of the character defined in claim 15, including at least one buoyancy tank mounted on the carriage for movement therewith.

Claim 24

Apparatus of the character defined in claim 15, including rollers supported on the carriage for disposal at least close to the top, bottom and opposite sides of the pipeline forwardly and rearwardly of said pair of wheels.

Claim 25

Apparatus for digging a trench beneath a pipeline, comprising a carriage, a pair of wheels mounted on the carriage for engaging the top of the pipeline at longitudinally spaced apart locations therealong, means urging said pair of wheels against the pipeline with a constant load, means for limiting upward movement of said pair of wheels with respect to the carriage, a third wheel mounted on the carriage for engaging the lower side of the pipeline intermediate the pair of wheels, means for driving said pair of wheels so as to move the carriage along the pipeline, cutter means, and means supporting the cutter means from the carriage for movement therewith.

Claim 26

Apparatus for digging a trench beneath a pipeline, comprising a carriage, a pair of wheels mounted on the carriage for engaging the top of the pipeline at longitudinally spaced apart locations therealong, means urging said pair of wheels against the pipeline with a constant load, means for limiting upward movement of said pair of wheels with respect to the carriage, a third wheel mounted on the carriage for engaging the lower side of the pipeline intermediate the pair of wheels, means for driving said pair of wheels so as to move the carriage along the pipeline, cutter means, and means supporting the cutter means from the carriage for movement therewith.

Claim 27

Apparatus of the character defined in claim 18, including at least one buoyancy tank mounted on the carriage for movement therewith.

Claim 28

Apparatus of the character defined in claim 18, including rollers supported on the carriage for disposal at least close to the top, bottom and opposite sides of the pipeline forwardly and rearwardly of said wheels.

Claim 29

Apparatus for digging a trench beneath a pipeline, comprising a carriage supportable on the pipeline for movement longitudinally therealong, cutter means, means supporting the cutter means from the carriage for movement therewith at least partially beneath the pipeline, a wheel assembly supported by the carriage for rolling engagement with the pipeline, means for driving at least a portion of said wheel assembly so as to move the carriage along the pipeline, a buoyancy tank mounted on the carriage near the forward end of the carriage and arranged with its center of buoyancy generally above the axis of the pipeline, a pair of buoyancy tanks mounted on the carriage above the pipeline near its rearward end and arranged in laterally spaced relation with their centers of buoyancy at generally equal lateral distances from the axis of the pipeline.

Claim 30

Apparatus for digging a trench beneath a pipeline, comprising a carriage supportable on the pipeline for movement longitudinally therealong, cutter means, means supporting the cutter means from the carriage for movement therewith at least partially beneath the pipeline, a wheel assembly supported by the carriage for rolling engagement with the pipeline, means for driving at least a portion of said wheel assembly so as to move the carriage along the pipeline, a buoyancy tank mounted on the carriage near the forward end of the carriage and arranged with its center of buoyancy generally above the axis of the pipeline, a pair of buoyancy tanks mounted on the carriage above the pipeline near its rearward end and arranged in laterally spaced relation with their centers of buoyancy at generally equal lateral distances from the axis of the pipeline.

Claim 31

Apparatus of the character defined in claim 21 wherein said wheel assembly is positioned intermediate the tanks near the forward and rear ends of the carriage.

Claim 32

Apparatus of the character defined in claim 21, wherein said cutter means is intermediate said tanks near the forward and rear ends of the carriage.