Ligna Two Saw Carriage Scrag End
Dogging
PURPOSE:
To saw logs from 6" to 24" diameter, 8' to 16' long
(nominal), by making two simultaneous cuts with two circular inserted tooth sawblades in a
single pass after positioning the log/cant and securing it by "dogging" on each
end. Additionally, this scrag is capable of returning a sawn cant back to the infeed
position for additional simultaneous cuts. If "four-sided" cants are required,
the initial sawn cant can be returned to the infeed position, rotated 90 degrees while
remaining "end-dogged", and sawn again to produce the "four-sided"
cant.
PRINCIPLE OF OPERATION:
A log is loaded in the infeed position. The operator rotates
the log with three "cradle chain" style log turners to obtain the best possible
processing position. After rotation, the computerized control system automatically
positions the log vertically to enable secure "end-dogging". The computerized
control system also calculates the nominal diameter of the log, and offers the operator a
variety of pre-determined sawing pattern solutions. The system can automatically select
the solution, or the operator can override the decision and select an alternate solution.
The operator then advances the carriage with "end-dogged" log into two circular
saws to accomplish the desired simultaneous cut. If resawing is required, the operator can
return the carriage and sawn cant to the infeed position, reset the saws, and repeat the
sawing function. He can also rotate 90 degrees for "four-sided" sawing. The
final sawn cant is released from the end-dogging system, deposited onto a chain conveyor,
and forwarded from the scrag for additional processing. Slabs and/or cut pieces are
removed from the saws by off-bearing belts onto dropbelts, which direct the pieces to a
waste processor (chipper) if in a "down" position, or to a removal rollcase (not
included with scrag) for additional processing. These functions are controlled by the
computerized system and the operator to determine position of cut pieces. The offbearing
and dropbelts are controlled by timing functions to permit sequential removal of cant,
then cut pieces onto the removal rollcase.
GENERAL DESCRIPTION:
This scrag features integrated construction, with the infeed,
center and outfeed sections mounted on a common frame consisting of 12" beam and
8" beam crossmembers. A top-driven carriage traverses the entire assembly, and is
reversible for reloading and/or multiple pass sawing.
Infeed Section:
- 12" beam and 4" tubular construction
- Capacity - maximum opening of 17'6"
- Note: At 17'6" opening , the minimum length is 7'6".
There is a 10' range between maximum and minimum processable log lengths due to mechanical
design criteria (e.g. if 16'0" is maximum log length, then 6'0" is minimum log
length)
- Three cradle style log turners with serrated-top #120 roller
chain individually powered by hydraulic motor with #100 roller chain drive; raised/lowered
individually by hydraulic cylinders, controlled by the computerized vertical log
positioning system to achieve alignment for "end-dogging"; nominal diameter
calculation by three ultrasonic devices (one per turner).
Center Section:
Two husk assemblies, each featuring:
- 12" beam and 4" tubular construction
- 2-15/16" mandrel with 8" saw collar
- 150 HP ODP 1800 RPM electric motor
- "5V" v-belt drive for 625 RPM
- NO SAWBLADE INCLUDED
- Above 150 HP motor and v-belt drive are designed for 56"
sawblades only
- 20" wide off-bearing belt, powered hydraulically
- Movement via linear bushings mounted on 2" hardened round
"WAYS"
- Computerized control system with setworks (developed as
pre-determined sawing solutions); Temposonics transducers to assist saw position, diameter
calculation, and 90 degree log/cant rotations; timing controls for all functions; complete
operators console with monitor; switch panels, cables and computer; all necessary controls
and switches (motor starters not included)
- One closed-circuit camera with monitor for
"blind-side" observation by operator
Outfeed Section:
- 12" beam and 4" tubular construction
- Two 22" wide, 12' long dropbelts, powered hydraulically,
activated by air cylinders
- Cant removal chain conveyor with WR 82 mill chain and flights,
running in 8" channel with steel wearstrip; powered hydraulically; controlled by
timing function of computerized control system; includes cant retaining guides
Carriage Section
Steel welded plate construction, with End Dogging System, Featuring:
- One spiked dog assembly on leading end - positioned by
hydraulic cylinder
- Two spiked dog assemblies on trailing end - positioned by
hydraulic cylinders (primary for small/average logs; secondary for large logs)
- The trailing end-dog system includes a 90 degree rotation
function for the production of "four-sided" cants. The primary trailing end-dog
assembly rotates via a hydraulic cylinder engaging a rack and pinion arrangement. A
Temposonic transducer measures the amount of linear travel by the stroke of the cylinder,
and the computerized control system converts the linear data into rotational data to
provide accurate rotation. The hydraulic system includes "ramp down" control to
reduce inertial effect of heavy logs.
- Overhead cable carriage drive system, powered by hydraulic
motor; including cable drum and sheave; 5/8" wire cable; variable speed (3 FPM to 150
FPM - nominal)
- Carriage supported on both sides by flat and machined steel
wheels traversing over carriage tracks; traverse controlled by operator
Hydraulic System:
50 HP Hydrostatic System , Featuring:
- 50 HP ODP 1800 RPM electric motor
- 46 GPM hydrostatic pump
- 120 gallon oil tank with filter; heater/cooler; necessary
hardware
- Hard pipe and hose plumbing with fittings and controls
Operator's Cab
- Nominal Size - 4'6" wide, 6'0" deep,7'0" high
- Front sloped wall with safety glass window
- Left/right walls with safety glass windows
- Door on rear wall, with safety glass window
- 1" sound suppression insulation
- Fluorescent light and receptacle
- Roof-mounted heater/air conditioner
- Operator's console with pedestal (starters not included)
