Portable saw with improved disconnectable platform for cutting concrete for controlling cracks

Apparatus for cutting grooves in a green concrete slab having at least one terminating side edge transverse to a broad top surface, comprising:

• a hand-held portable rotary saw having a housing, a guide plate defining (i) end and side edges and (ii) a broad undersurface and opening therethrough, a saw blade being attached to said housing rotatable relative thereto about an axis of rotation in an up-cut direction, said saw blade including an outer curved sector extending through said opening of said guide plate, means for releasably attaching said guide plate relative to said housing to permit incremental rotation of said guide plate relative to said housing to change height of said axis of rotation of saw blade relative to a first working plane of reference through said guide plate,
• rollable platform disconnectably connected to and supporting said saw atop a green concrete slab, said rollable platform including a planar base in surface contact with said guide plate of said saw, said planar base in surface contact with said guide plate of said saw, said planar base having a rearward anchoring portion adapted to receive a human-generated force to provide said platform and said saw with rectilinear travel along a preselected direction over said green concrete slab having a top surface, said planar base also including a slot in alignment with said opening of said guide plate through which said sector of said saw blade extends, said saw blade defining a second working plane of reference that intersect said axis of rotation of said saw blade and intersect said top surface of said green concrete slab and intersects said first working plane of reference of reference whereby a maximum of cut generated by said saw blade relative tao said top surface of said slab during operations, is defined coincidental with said second working plane of reference and is measured relative to said first working plane of reference,
• a set of rollers attached to said rotatable platform in rolling contact with said green concrete slab to facilitate said rectilinear travel in said pre-selected direction, said set of rollers including first and second front rollers and third and fourth rear rollers, said front and rear rollers each defining a pair of coincident axes of rotation normal to said pre-selected direction, said front and rear rollers also defining first and second transverse dynamically occurring rolling planes, respectively, each of which being coincident with respective axis of rotation and coincident with respective intersections of said front and rear rollers with said top surface of said green concrete slab,
• said rolling planes being positioned such that (i) said rearward anchoring portion of said planar base adapted to receive said human-generated force, stabilizes said platform and said saw during said rectilinear travel across said green concrete slab, and (ii) said second working plane of reference is forward of both rolling planes (1) whereby minimum disruptive forces are imparted to said saw blade during said rectilinear travel and (2) wherein said saw blade completes its maximum cut well prior to said front pair of rollers encountering any transverse terminating edge of said green concrete slab.