Abstract: A cutting apparatus includes a support structure and first and second cutting assemblies. Each cutting assembly includes a rotatable cutting head and a mounting assembly for movably attaching the cutting head to the support structure. The cutting head is movable about a first pivot axis of the mounting assembly in a sideways direction relative to the support structure, and about a second pivot axis in an upwards-downwards direction. Each cutting head includes a plurality of cutting units, which each have a rotatable shaft and a cutter mounted thereon. The cutter includes a disc body and a plurality of buttons mounted in a radially peripheral portion of the disc body. At least some of the buttons have a central longitudinal axis that subtends an angle ? to a reference axis, which extends perpendicularly outwards from an axis of the shaft, the angle ? being ?to 20° and ?to 34°.

Abstract: A system and method for high wall bench mining, for example, of horizontal coal seams in mountains, includes a launch platform having two side-by-side tracks for guiding mining equipment, and utilizes two continuous miner machines and conveyor cars. Two side-by-side mine entries can be worked simultaneously, one miner advancing deeper into the coal seam and conveyor cars being added behind the miner at a first mine entry, and the mining completed and cars and miner retreating and being extracted from a second mine entry. As conveyor cars are being extracted onto one track from the mine entry that a string is retreating from, the cars are moved across the launch platform to the other track and are added behind the advancing miner machine launched from that track into the other mine entry.

Abstract: A drill bit exchange device for a shield tunneling machine includes: a housing with an aperture; a valve body housed in a chamber of the housing, the valve body being pivotable about a pivot axis (Ob) inclined at a predetermined angle with respect to an axis perpendicular to the front of a cutter head; a bit-housing hole formed in the valve body to detachably accommodate a bit; and an exchange seal recess located at the front of the chamber and at a symmetrical position from the aperture with respect to the pivot axis (Ob). The valve body is pivoted about the pivot axis (Ob) to move the bit, which faces the aperture, to the exchange seal recess, allowing the bit to be removed from the bit-housing hole and exchanged.

Abstract: Forming a sequence plan for a machine to travel to a series of specified locations is described. An initial cost table (414) and a pattern of locations (412) is inputted to a Sequential Ordering Problem (SOP) solver (402). The resulting sequence (410) is processed by a motion planner (404) to derive by a motion planning procedure a plan of machine motions through the sequence. A cost table update (408) is performed based on the motion plan, which is then used for another iteration of the SOP solver (402).

Abstract: An EPB shield machine without disc cutter, which includes a partition unit formed by a moveable partition member (30) and a stationary partition member (31), a front shield unit (13) including a cutting unit (1) with cutting head (11) and cutting teeth (12), a shaft member (2) connected to the cutting head (11) and a power transmission unit formed by a transfer case (5), a reducer (6) and a driving motor (7). In the power transmission unit at an upper portion of the machine, the transfer case (5) is fixedly to the moveable partition member (30), a sliding arrangement supports the reducer (6) and the driving motor (7), which are connected to the transfer case (5, and a telescopic cylinder (26) is connected to the sliding arrangement. The machine has advantages of high cutting efficiency, balanced service life, high directional construability and high adaptability to tunnel cross section.

Abstract: A tunnel boring machine (100) includes a cutterhead assembly (102) rotatably mounted to a forward shield assembly (116) through a cutterhead support assembly (110). The cutterhead support assembly is configured to receive a variable number of drive assemblies (105), such that the number of drive assemblies may be selected after fabricating the cutterhead support structure (120). The cutterhead support structure includes a housing portion (121) that houses the main bearing assembly (101) and a drive gear (104). A plurality of drive mount stations (111) provide access to the drive gear, and are provided with a pinion housing (130) for stations that receive a drive assembly, or with a cradle cover (140) for stations that do not receive a drive assembly.

Abstract: A drill bit exchange device for a shield tunneling machine includes: a housing with an aperture; a valve body housed in a chamber of the housing, the valve body being pivotable about a pivot axis (Ob) inclined at a predetermined angle with respect to an axis perpendicular to the front of a cutter head; a bit-housing hole formed in the valve body to detachably accommodate a bit; and an exchange seal part located at the front of the chamber and at a symmetrical position from the aperture with respect to the pivot axis (Ob). The valve body is pivoted about the pivot axis (Ob) to move the bit, which faces the aperture, to the exchange seal part, allowing the bit to be removed from the bit-housing hole and exchanged.

Abstract: The invention relates to a method for introducing a vertical shaft underground and to a shaft driving machine set up particularly for performing the method, wherein a cutting wheel is rotated solely about a horizontal axis until a penetration trough having a predetermined penetration depth is formed, and the cutting wheel is then also rotated about a central vertical axis until a shaft foot is dug out to the penetration depth. A relatively high sinking rate is thereby achieved for the shaft.

Abstract: An apparatus for the milling cutting of rock, minerals or other hard materials has a tool drum which is rotatably mounted on a drum carrier about a drum axis and on the peripheral shell surface of which are disposed, in distributed arrangement, a plurality of tool carriers, which carry cutting tools and can be rotatingly driven, where their shaft axes run transversely to the drum axis. A first group of tool carriers and a second group of tool carriers are provided, where the rotational direction of the first group is counter to the rotational direction of the second group, and the shaft axes of the tool carriers of the first group and of the second group are oriented at different setting angles relative to the radial direction of the tool drum.

Abstract: A tunnel boring machine (100) includes a cutterhead assembly (102) rotatably mounted to a forward shield assembly (116) through a cutterhead support assembly (110). The cutterhead support assembly is configured to receive a variable number of drive assemblies (105), such that the number of drive assemblies may be selected after fabricating the cutterhead support structure (120). The cutterhead support structure includes a housing portion (121) that houses the main bearing assembly (101) and a drive gear (104). A plurality of drive mount stations (111) provide access to the drive gear, and are provided with a pinion housing (130) for stations that receive a drive assembly, or with a cradle cover (140) for stations that do not receive a drive assembly.

Abstract: A ripper tool for a tunnel boring machine includes a tool body and a plurality of cutting element inserts. The tool body has a plurality of socket cavities. A tool body blank can be heat treated to increase the hardness of the tool body blank. The socket cavities can be machined in the tool body blank after the tool body blank is heat treated. The cutting element inserts are mounted to the tool body. The cutting element inserts are respectively press fit in the socket cavities. The ripper tool can be pivotably mounted to a cutter head of the TBM.

Abstract: The invention relates to a method for introducing a vertical shaft underground and to a shaft driving machine set up particularly for performing the method, wherein a cutting wheel is rotated solely about a horizontal axis until a penetration trough having a predetermined penetration depth is formed, and the cutting wheel is then also rotated about a central vertical axis until a shaft foot is dug out to the penetration depth. A relatively high sinking rate is thereby achieved for the shaft.

Abstract: The present invention relates to a novel method of mining underground coal and recovering coal seam gas, the method including locating a seam of coal; digging a mine shaft to reach the seam of coal; constructing a ventilated underground control center which includes a computerized control panel, wherein the computerized control panel controls the movement of a drill head, a hollow drill shaft, a movable hydraulic shield, a movable resin roof bolting machine, and a movable waste extrusion device; providing mining personnel to the ventilated underground control center; wherein the mining personnel operate the computerized control panel to perform the tasks of moving the drill head into the seam of coal to obtain aggregate coal and coal seam gas; extruding waste material into mined-out space of the coal seam; and transferring the aggregate coal and coal seam gas to the surface of the earth.

Abstract: A boring machine includes a steering head which is located behind a cutter head. The steering head has a plurality of steering openings spaced around its periphery. A steering component is mounted adjacent to each steering opening, and each steering component includes a steering paddle that is pivotally mounted with respect to the steering head so as to pivot about a paddle pivot axis. Each steering component also includes a linear actuator and a force multiplier. The linear actuator operates to direct an actuating force along a line that is parallel to the longitudinal axis of the steering head, and it cooperates with the force multiplier and the steering paddle so that upon operation of the linear actuator, a pivot force which is the product of the actuating force and a multiplier factor greater than one causes the steering paddle to pivot about the pivot axis.

Abstract: A boring machine includes a cutter head, an internal casing and an auger that is located within the internal casing. The cutter head and the auger are operationally connected to a rotational mechanism. A rear bulkhead is located at the rear end of the auger, and a rear hopper is located behind the rear bulkhead. The boring machine also includes means for directing material cut by the cutter head into the auger so that rotation of the auger will convey such material rearwardly to the rear hopper. The boring machine includes a transverse conveyor located behind the rear bulkhead in the rear hopper which is adapted to convey material out of the rear hopper in a direction transverse to the longitudinal axis of the auger.

Abstract: The milling head (1) which serves for the machining of the head (80) of a pile (8) consisting of a pile core (81), a pile shaft (82) and a metal reinforcement lying therebetween comprises a coupling device (13) that can be connected to a drive shaft (2) and a plurality of picks (111, 121) that are used to remove concrete. According to the invention a central milling cutter (11) provided with a plurality of central picks (111) and an annular milling cutter (12) provided with a plurality of annular picks (121) are fixedly coupled with each other and arranged coaxially with the longitudinal axis (x) of the drive shaft (2). The central picks (111) are arranged within a central circle (kr1) and the annular picks (121), separated by a middle circle (kr2), are arranged in an outer circle (kr3), whereby the circles (kr1, kr3) lie at least approximately perpendicular to and concentric with the longitudinal axis (x) of the drive shaft (2).

Abstract: In a starter car for a drilling device for mining underground deposits, including a base frame (5) mounted to rotate about a vertical axis (6) and a starter pipe (7) mounted to pivot about a substantially horizontal axis (13) and provided for receiving the drilling device, the starter pipe (7) is arranged to be displaceable relative to the base frame (5) transversely to the horizontal pivot axis (13).

Abstract: An apparatus for the milling and/or drilling cutting of materials, in particular for the removal of rock, minerals or coal, with a tool drum which is mounted on a drum carrier rotatably about a drum axis, in which a plurality of tool shafts, which carry cutting tools at their ends projecting from the tool drum, are rotatable drivable mounted, at least two of the tool shafts being drivable by a common gear drive which has power take-off gearwheels arranged fixedly in terms of rotation on the tool shafts, and a common drive element which cooperates with the power take-off gearwheels. The drive element and the tool drum being rotatable in relation to one another and the shaft axes of the tool shafts standing transversely to the drum axis.

Abstract: A rotary cutter for a tunnel boring machine or similar machine has a cutter ring mounted to a hub. The hub is mounted on a shaft. A sleeve bearing system is positioned between the hub and the shaft for supporting the hub on the shaft and allowing relative rotation. A duo-cone seal assembly is positioned between the hub and the shaft to seal out contaminants from the sleeve bearing system. An oil gallery with lubricating oil for lubricating the sleeve bearing system is provided in the shaft.

Abstract: A mining machine includes a cutting mechanism with an arm, and a substantial weight of more than a thousand pounds attached to the arm. The mining machine also includes a first disc cutter adapted to engage the material to be mined and mounted on a first disc cutter assembly for eccentrically driving the first disc cutter, the first disc cutter assembly being mounted within the substantial weight. The mining machine also includes at least a second disc cutter spaced apart from the first disc cutter assembly and adapted to engage the material to be mined, and mounted on a second disc cutter assembly for eccentrically driving the second disc cutter, the second disc cutter assembly being mounted within the substantial weight.

Abstract: The present invention is directed to the separation of bitumen, such as by the Clark process or by a countercurrent de-sander, in an underground excavation machine, such as a tunnel boring machine.

Abstract: A boring rig (14) for underground boring for excavating purposes and including a substructure (21, 22), a propulsion device, a stabilizing device (31, 32, 35, 36, 37, 38, 39, 42), and a boring unit (20) having a cutter head (29) and a rotation and forcing device (26), in which the rig has a first direction of general travel and two sideways directions, and in which the boring unit (20) is pivotally attached to the substructure for pivotal movement of the boring unit into an operating direction. The stabilizing device includes horizontal (31, 32) and vertical (35, 36, 37, 38, 39) stabilizing elements that are attached to the substructure (21, 22) in order, in active positions, to be pressed against an adjacent rock face so as to transmit forces from the boring unit (20), that are occurring during boring, to the rock face.

Abstract: An auger support assembly for use with an augering system for mining which bores a pair of side-by-side holes through a coal seam using dual side-by-side augers. Each auger includes a drilling section which is followed by a series of auger flights for conveying the bored coal back out of the respective hole. The augers are connected together in axially aligned pairs and are supported by the auger support assembly. The auger support assembly includes a pair of bearing housings that are disposed on drive shafts which extend outwardly from the first ends of a first pair of parallel augers and are received within the second ends of a second pair of parallel augers. The bearing housings are connected to each other by a tie bar. A single support leg extends downwardly from approximately the mid-section of the tie bar to engage the ground ledge that is formed between the counter rotating augers.

Abstract: A shield tunneling machine has a shield body and a cutter head rotatably provided at the forward end of the shield body in the excavation direction. Abrasive jet spray nozzles for spraying abrasive jet water are movably provided on the cutter head. Obstacles encountered during excavation can be broken efficiently with high cutting quality by properly controlling the movable abrasive jet spray nozzles according to the size and configuration of each particular obstacle.

Abstract: An excavating drive (22) movable backward/forward is accommodated in a turnable body (9) which in turn is turnable about an axis perpendicular to an axis of and in a skin plate (7). A cutter device (38) ahead of a rotor (22) in the excavating drive (22) is composed of a center cutter (40) supported by the excavating drive (22) and a plurality of face plate shaped expansion cutters (44) fitted to an outer periphery of the center cutter (40) for pivotal movement backward/forward. Tunneling is effected by the expanded cutter device with the expansion cutters (44) being pivoted forward. Upon replacement of bits (35; 35?), the expansion cutters (44) are pivoted backward for contraction of an assembly of them and the cutter device (38) is accommodated in a turning trajectory (R) of the turnable body (9) so that the turnable body (9) is turned backward for replacement of the damaged bits (35; 35?) backward.

Abstract: The present invention is directed, inter alia, to devices and methods for excavating valuable materials, particularly soft ores such as oil sands, oil shales, and the like, that use one or more of a number of features, including backfilling for ground support, a small trailing access tunnel, processing of the valuable material in the excavation with the tailings optionally being used as backfill and the valuable material being transported to the surface, a plurality of movable shields for ground support, and/or a movable tail shield to provide interim support to the backfill while additional liner sections are installed and/or formed.

Abstract: A tunnel boring including a rotatable head is disclosed. The head has a cutting face transverse to a head axis of rotation. A plurality of cutters are mounted in the face each on an associated one of a plurality of hubs. The hubs mounted for rotation about a respective hub axes. Each such respective hub axis is in an imaginary plane intersecting another imaginary plane including the head axis. Each of the cutters has a cutting edge symmetrical about another imaginary plane which is skewed with respect to the respective hub axis of the associated hub.

Abstract: Control apparatus for a horizontal boring tool is described which drives a boring lance via boring rods. The tool includes an input interface for receiving actual values of controlled variables of the horizontal boring tool, and an output unit for issuing control signals for controlling the horizontal boring tool. Between the input interface and the output unit is provided a fuzzy control unit which determines the control signals for activation of the horizontal boring tool from the actual values of the controlled variables and the desired values for the controlled variables by fuzzy logic while taking into account heuristic process values. The control apparatus permits automatic operation of the horizontal boring tool with good course steering and high precision.

Abstract: A method and apparatus for cutting a borehole substantially in the shape of a bread loaf within a mine includes four cutting systems. The first cutting system is a pair of three-armed, counter rotating, cutting heads which remove material from the mine face in a substantially vertical plane. The second cutting system is a pair of rotating cutting drums which follow the pair of counter rotating cutting heads. The third cutting system is a substantially vertical, rotating cutting head which removes the kerf formed at the ceiling or roof portion of the borehole. The fourth cutting system is a plow which both removes the kerf at the bottom of the borehole and directs the mined material to a conveyor system to remove the mined material from the mine.

Abstract: The invention relates to equipment for drilling a vertical borehole in hard ground, the equipment comprising:

Abstract: An underground augering system comprising a drill unit adjustably connected to a retrieving unit by interchangeable and adjustable connectors to provide for simultaneous drilling of one hole and the removal of auger flights from a previous drilled hole, a crowd mechanism within each unit to move the drill and retrieval carriages to and from holes, a transfer arm to move auger flights to and from a staging rack within the retrieval unit and belly pan within the drill unit, and belly pan within the retrieval unit, a mechanism and staging rack for the storage of auger flights, and a delatch mechanism within the drill unit and retrieval unit to disengage the latch lever in an auger flight for removal of the auger flight from a string of auger flights.

Abstract: A cutter head is rotationally drivably mounted on a front portion of a tunnel excavating machine body, a plurality of cutter spokes are provided radially on the cutter head, a plurality of mounting holes are formed in a front surface portion of each of the cutter spokes, a valve plate is turnably mounted and has through-holes formed in correspondence with the mounting holes, relay bits are mounted movably to the through-holes and the mounting holes and rearwardly withdrawably, the relay bit can be fixed by bolts at a position at which the relay bit protrudes from the front surface portion of the cutter spoke, and when the relay bit is withdrawn rearward from the mounting hole, the valve plate is turned to close the mounting hole, whereafter the relay bit is detached and can be replaced.

Abstract: It is an object of the present invention to provide a tunnel excavating machine of high-speed construction type and an excavation method which is capable of stopping invasion of water completely and allows covering members to be assembled easily.

Abstract: Cutter spokes are disposed on a cutterhead of a tunnel-excavating machine. Movable blocks, each having a roller cutter, are movably supported by each of the cutter spokes while being connected one another by means of a connection link. A gate mechanism is attached to an end portion of each of the cutter spokes. A machine body is equipped with a roller cutter accommodation box such that through rotation of the cutterhead to a predetermined angular position, the roller cutter accommodation box can be selectively and removably engaged with the end portion of any one of the cutter spokes via the gate mechanism.

Abstract: An excavator including a center shaft rotatably provided in a shield body in concentric relation to an outer cone. An inner cone for crushing excavated materials in cooperation with the outer cone is eccentrically provided on the center shaft. A cutter head provided in front of the inner cone is mounted on the center shaft. An internally-toothed gear is secured to the inner cone in concentric relation to the center shaft. A plurality of externally-toothed gears rotated by driving motors whose rotational speed and torque are variably controllable are internally meshed with the internally-toothed gear. Rotation of the externally-toothed gears causes the center shaft to rotate through the inner cone. A plurality of water jet spray nozzles are provided on the cutter head. The spray pressure is switched between high pressure and low pressure.

Abstract: A method of boring a tunnel with a tunnel boring machine comprising injecting into the formation to be bored just before the cutting tools of the boring machine and optionally into the internal discharge chamber of the boring machine, an aqueous foam containing at least one clay, at least one surfactant and at least one gas in proportion to produce a good quality, stable foam with the formation material and discharging the material from the tunnel via the discharge of the boring machine.

Abstract: A drive steel member for driving engagement with a rotary drilling machine, including a chuck adapter having main body and chuck seating elements and being constructed and arranged in fixed, sealing relation on on one end of the drive steel member.

Abstract: A boring machine having a cutter head rotatably mounted on a hydrostatic bearing. High pressure water is supplied to passageways between confronting bearing surfaces which react axial and radial loads and which are capable of relative rotational movement. The flow of pressurized water discharges from the passageways to prevent contamination of the bearing by the ingress of material removed by the cutter head in operation.

Abstract: A cutter head for use in the removal of hard rock. The cutter head combines a standard cutting member, such as button bits or wedge-lock cutters, with cutting blades having a diamond cutting surface. The cutting blades cutting surface is positioned above the standard cutting members so that in operation, the cutting blades form grooves in the rock face and the standard cutting members fracture the rock adjacent the grooves through tensile forces.

Abstract: The tunnel drilling machine or tube-driving machine for hard rock drilling has a drill head (19) supporting drilling tools (1 to 18) which has a diameter which is less than the diameter of the bore. The geometric axis of the circle of the envelope of the tools of the full-width drill head (19) is disposed eccentrically in relation to the linear tunnel axis (22) or the axis of rotation (21) or can be displaced.

Abstract: Preliminary cutter units of a shield machine provided with preliminary cutters capable of continuously excavating soil in a working place even if main cutters are worn away.

Abstract: In a tunnel excavator for tunneling by rotating a cutter head provided in front of a shield body to thereby excavate the working face of a tunnel using disk cutters attached to the front surface of the cutter head, the cutter head is composed of an annular beam, an arched main spoke provided across the annular beam and a plurality of arched sub-spokes radially provided thereon and disk cutter assemblies are detachably attached to the main spoke and sub-spokes, so that the disk cutter has a simple structure and the reaction force of excavation is broken up by the main spoke and sub-spokes to be transmitted to the annular beam. As a result, it is possible to provide a strong and durable cutter head which can be easily manufactured.

Abstract: An improved method for assembling a stem within a mating, close fitting hole of a raise boring head by attaching an overhead beam to the body of the raise boring bit, supporting the stem with its longitudinal axis aligned with that of the beam and that of the mating hole, and moving the stem along its axis to assemble the stem in the mating hole. A coating of wear resistant material on selected regions of the stem employs a softer material than that of the stem or the mating hole to minimize damage to the hole during assembly.

Abstract: A machine for removing slag and metal remainders from crucibles or casting ladles includes a frame on which is disposed a carriage movable in an upwardly inclined direction on guides or rails. The carriage is provided with cutter device having a tool head. A holder for a crucible is tiltable from a first position where the crucible can be placed on the holder to a second, operating position where the crucible is coaxial with the cutter device. The cutter is of the full profile type and is provided with a plurality of first tools which are spaced apart along the periphery of the tool head and second tools which are spaced apart in the radial direction on a front part of the tool head. The second tools are arranged so that the bottom of the crucible will be cleaned completely. The tool head is provided with axial through holes for the transportation therethrough of slag and metal remainders.

Abstract: An apparatus for cross-sectionally enlarging a chimney flue includes a fluid motor; a milling cutter mounted on the fluid motor and being driven thereby for removing constructional wall material from walls defining the flue; a suspension device for supporting the fluid motor and the milling cutter as a unit and for raising and lowering the fluid motor and the milling cutter in the chimney flue; a fluid pressure source; a hose connecting the fluid pressure source with the fluid motor for supplying the fluid motor with pressurized fluid from the fluid pressure source; a guiding device arranged about and travelling with the fluid motor for engaging the flue walls to guide the fluid motor in the flue; and a device for varying a radial position of the guiding device relative to the motor axis.

Abstract: An underground excavator includes a chamber defined in the forward section of an excavator body for receiving excavated material such as soil, sand, gravel, clay and their mixtures. A rotary cutter is mounted to the forward end of a rotary shaft for penetrating through the chamber for axial rotation and simultaneous rocking in an axial direction. The cutter has a conical cutter face plate having holes for passing the excavated material of a diameter smaller than an opening disposed in the chamber. Any gravel or the like present in the advancing route to the underground excavator and smaller than the holes of the cutter is received into the chamber to be discharged from the excavator. Any gravel larger than the holes or the like not receivable into the chamber is moved quickly along the conical cutter face plate toward peripheral ground layer by being subjected to the rocking motion of the conical cutter face plate simultaneously with the rotation of the cutter during advancement of the excavator.

Abstract: A percussion tool usable as part of a single tool impact device or a multi-tool impact device. In each case, the tool is rotatably driven by a high-torque rotary actuator with the tool being longitudinally splined and received within a correspondingly longitudinally splined hollow drive shaft of the actuator. The tool extends fully through the drive shaft to a rearward end thereof at which is positioned a percussion hammer to provide reciprocating endwise impact to the tool. The tool is held within the drive shaft by a splined lock member which can be rotated between a release position with its splines aligned with the drive shaft splines, and a locked position with its splines misaligned with the drive shaft splines. The device is mountable on a mobile vehicle having an articulated arm.

Abstract: The two ends of the luffable and swivelable arms of the gantry of an overburden excavator each have a horizontal bolt for a frame of the drive, on the axis of rotation or drive shaft of which is mounted a rotary cutter in the form of a cutter drum. The rotary cutters are disposed on both sides of a receiving conveyor. The axes of rotation of the shafts rotating the rotary cutters are oriented approximately parallel to the plane of symmetry (longitudinal axis) of the receiving conveyor belt. The angle of the rotary cutter axis can be adjusted in relation to the plane of the roadway by the length adjuster in the form of a hydraulic or pneumatic cylinder, which is located between a bearing lug of the arm and a bearing lug of the frame. The rotary cutters transport the material via transverse conveyors to the converyor belt.

Abstract: A tunnel boring machine for boring a curvilinear tunnel in earthen strata is described.

Abstract: The machine comprises an automobile vehicle provided with a pivoting boom to which is pivotably mounted a beam carrying a pivotally mounted swingle-bar to which is coupled a rotary plate for supporting a frame provided with guiding uprights for a sawing unit. Hydraulic cylinders and motors are provided for adjusting respective positions of the boom, beam, swingle-bar, rotary plate and motor means of the sawing unit. Means are provided to maintain the frame in a fixed position when working a sawing step.