Note: Descriptions are shown in the official language in which they were submitted.
CA 02664221 2009-04-27
TITLE
POWER TROWEL AND GRINDING PAN
FIELD OF INVENTION
[0001] The present invention relates to masonry, and more specifically to
power
trowels and grinding pans used for troweling and finishing floor surfaces.
BACKGROUND OF THE INVENTION
[0002] Any laid concrete or cement (or the like) used in making a floor,
driveway, or
the like, must be troweled when still relatively wet (as judged by one of
ordinary skill in
the art), to be made generally flat.
[0003] Troweling manually with a hand-held trowel is known, but is problematic
because of its excessive time cost, and because it is physically arduous to
trowel by hand.
Such hand-troweled floors are generally not uniform in finish (arm movement
direction is
restricted, and required energy input is limited).
[0004] Power-trowels, meaning a housing containing a motorized fan-shaped
multi-
trowel attachment are problematic for finishing floors because they run at a
fixed speed
(after a short period of initial acceleration), and so often cannot produce
desired finishes.
Many concrete or cement floor finishes ideally require troweling at various
speeds,
according to prevailing circumstances and conditions of the concrete or cement
(as judged
by one of ordinary skill in the art).
[0005] Very coarse floors require additional finishing in the form of
grinding, which
requires different machinery. Switching machinery is time-consuming, and
wastes energy
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over using a single machine. Also, grinding (grating a surface from not level
to level,
using one or more grits) is physically arduous, dangerous, and normally
requires
machinery heavier and more expensive than a power-trowel machine.
[0006] A preferred embodiment of the first invention is a power trowel
machine.
This power trowel machine comprises a housing and a plurality of trowels
attached to the
housing in a fan arrangement. A driver is operatively connected to the fan
arrangement to
drive the arrangement at a set speed. A handle defining two ends and having
the first end
attached to the housing, extends outwardly away from the housing, with the
second end
being adapted for grasping by a user.
[0007] In another embodiment of the first invention, comprises a variable
speed
controller operatively connected to the driver, to vary drive speed.
[0008] A preferred embodiment of the second invention is a pan shaped for
attachment to a plurality of trowels of the kind found in power trowel
machines. The pan
defines an inside and an outside. The pan has engagements for cooperative
connection to
the trowels. The engagements are on the pan inside. Grits are attached to the
pan outside,
for grinding.
[0009] In another embodiment of the second invention the grits are releasably
attached to the pan outside.
DRAWINGS
[0010] FIG. 1 is a perspective view of a power trowel with releasable pan.
[0011] FIG. 2 is a partial perspective view of a variable speed controller and
rotation
dial.
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[0011] FIG. 3 is a flat view of a pan with grit pucks.
[0012] FIG. 4 is a flat view of a pan with grit pucks.
DETAILED DESCRIPTION OF THE DRAWINGS
[0013] A trowel (30) is a flat blade used for spreading. Trowels (30) are used
in
masonry and the like. A power trowel machine (10) has a housing (20), which
contains a
fan-shaped arrangement of trowels (30) (Fig. 1 as example). Power trowel
machines (10)
have a driver (40) (a motor (gas, electric, magnetic or otherwise)). A fan
shaped
arrangement of trowels (30) is an arrangement of trowels (30) projecting
radially outward
from a common centre. The arrangement permits revolutionary movement.
[0014] The power trowel machine (10) of the first invention is shown by
example
(Fig.1) and can have a fan shaped trowel (30) arrangement encased in a housing
(20), and
powered by a driver (motor) (40). The driver (40) drives (moves) the fan
arrangement in
revolutionary movement, at a selected speed, after brief initial acceleration
from rest. The
driver (40) speed can be varied by providing a variable-speed controller (70).
To optimize
the varying of driver (40) speed, a standard rotational dial (100) (Fig. 2)
can be provided.
The controller (70) communicates with the driver first by way of a
transmitting cord (90),
which in turn enters a computer housing (80) eventually transmitting to a
computer (not
shown). The computer (not shown), on command, varies driver (40) speed to
correspond
with the dial (100) setting.
[0015] The machine has a handle (50) defining two ends. The first handle end
is
attached to the housing (20). The handle (50) extends outwardly away from the
housing
(20). The second end of the handle is adapted for grasping by a user (not
shown). The
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controller (70) can be attached anywhere on the machine (10), and for
convenience is
preferably attached proximal the handle second end (in the same general
vicinity as the
cut-off switch (60)).
[0016] The machine (10) has a cut-off switch (60) attached to the handle
second end.
The cut-off switch is changeable between two states; a first where it engages
the driver (40)
to drive the fan arrangement, and a second where it disengages the driver (40)
to cease
driving. If the machine (10) runs on electricity, a power plug (160) can be
provided.
[0017] Varying driver (40) speed through a controller (70) according to
prevailing
conditions allows floors to be finished to a wider and more accurate range of
desire than
manual troweling at varing speeds, or power troweling at a fixed speed, both
according to
industry standard.
[0018] The second invention is a pan (110) (Fig. 3) shaped for attachment to a
plurality of trowels (30) like those in the fan arrangement of Fig. 1. The pan
defines an
inside (Fig. 1) and an outside (Fig. 3 & 4). The pan has engagements (120) for
cooperative
connection to the trowels (30), and the engagements (120) are attached to the
pan (110)
inside (Fig. 1). The pan outside (Fig 3 & 4) has (preferably but not
necessarily releasable)
grit pucks (grinders) (130). A grit puck (grinder) (130) is a structure
adapted to grind or
sharpen a surface from not level to level. Grit (130) size, shape, form,
construction, and
coarseness can all vary, so long as the puck (130) can grind according to
desire. Grits (130)
can be attached to the pan (110) by fasteners (like screws) (150), or for more
easy puck
(130) release, by hook and loop strap (140) of which VelcroTM is an industry
standard.
[0019] When attached to a power trowel machine (10) the pan (110) can finish
(grind) floors according to a wider and more accurate range of desire than
manual
grinding, and does not require a different machine apart from the power trowel
machine
(10).
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