allen RS844, Руководство по эксплуатации и запасным частям, Страница: 29 / 130

057625 - 10/2012
SECTION 2
OPERATIONS
Page 2-3
2.1 General Information (continued)
The Roller Screed is composed of frame sections which vary in length from 1 ft. (.3 m) to 6 ft. (1.82 m).
These frame sections support the paving tube which runs along the front of the screed.
The screed is equipped with two sets of independently controlled rubber-coated drive tubes. These
drive tubes are located at each end of the screed (operator end/power unit end) and are controlled by
two separate control levers.
Since the drive tube levers are independent of each other, one set of drive tubes can travel forward,
while the other set of drive tubes travels backwards. Using the levers in this way lets the operator steer
the screed.
Two sets of rubber caster wheels provide easy manuvering when placement of the screed onto rails or
forms is required.
The Roller Screed is height adjustable by means of four separate jack assemblies. These jack assem-
blies have a crank handle that allows the operator to raise and lower the screed.
The power unit is powered by Kubota diesel engines, a 32HP on the RS832 and a 44 HP on the RS844.
Coupled to the diesel engine is a hydraulic drive pump which provides the hydraulic pressure neces-
sary to rotate the drive and paving tubes.
Inadequate substrate and form support can lead to form failure causing unnecessary job delays and
expenses while contributing to poor floor flatness and floor levelness ratings.
The intent of the form specifications is to establish minimum guidlines to help the contractor choose the
most economical and effective formwork/support system for the job application.
It is recommended that at least the day prior to the concrete pour, a dry run be accomplished to test the
load capacity of the forms and substrate. Proper job planning is essential to a successful application.
Subgrade must be sound enough to support slab edge forms and bracing as well as the load imposed
by the screed and its support. Potential deflections, as in the case with metal and plywood decks,
should be considered when determining brace and support spacing.
Soil substrates must be well compacted and must be able to support bearing pressures greater than or
equal to those imposed by the screed supports and the slab forming.
For proper bearing support, shims should be used to adequately distribute loads where grade is not
level or is soft. Use standard ACI concrete form pressures when calculating lateral loads on slab edge
forms.