[0001] This invention, as is expressed in the heading, consists of a machine tool that incorporates
a mechanism for stripping plaster, concrete, tiles, etc, off wall or floor surfaces.
Therefore, it will be used in the construction field, both in new and renovation work.
[0002] This invention's main advantages are that it manages to reduce the cost in such work
as well as the labour; furthermore, it improves the quality since, as surfaces are
removed evenly, the new surfaces find greater adherence.
INVENTION DESCRIPTION
[0003] One of the aims of this patent is to improve the execution of these jobs.
[0004] 1 - In the stripping machine tool, the movement of the impact hammers is caused by
a motor, which, therefore, eliminates the human effort which would be required to
remove wall or floor surfaces manually. The machine tool can be used by one person
on their own, thanks to its small size and light weight.
[0005] 2 - The impact hammers are positioned in such a way that, as they go over the area,
a wide strip is removed off the surface; this width can be increased depending on
the power of the motor used, thus considerably reducing the work time required.
[0006] 3 - Adjustable rods act as stops situated on either side of the machine tool's head
assembly shaft; these rods allow the penetration depth of the hammers to be adjusted
according to work requirements.
[0007] 4 - The machine tool incorporates a water spray device, fitted on the shield, which
is aimed directly at the area being removed by the hammers, in order to eliminate
the dust produced while in operation.
[0008] 5 - The machine tool can be used not only when the work area is near an electrical
power point but also when electrical power is not available since it may incorporate
an electric motor or an internal combustion engine.
INVENTION BACKGROUND
[0009] The techniques currently available for the removal of surfaces are primarily manual.
A workman equipped with a chisel and hammer hacks away at the wall or floor surface,
but this method is hard work and costly.
[0010] A pneumatic hammer may also be used: it is a device that has a shaft with a pointed
end; a pneumatic system makes the shaft hammer repeatedly against the surface to remove
material. With this system only a small surface area is worked on at a time; every
blow eliminates a small piece of material and it is difficult to control penetration
depth.
DESCRIPTION OF SUGGESTED IDEAL DESIGN
[0011] For a better understanding of how the machine tool works, a description is offered
with references to the drawings included in the following pages.
[0012] The surface stripping machine tool consists of, in its main mechanism (Fig. 4 and
Fig. 5), a set of discs (1), which have a deep internal groove machined transversally
to their centre axis. The groove houses the impact hammers (2) which are toothed to
improve penetration capacity and which are held in place by shaft (3) with the appropriate
fixing elements.
[0013] The impact hammers are divided into two pieces which are screwed together, a body
(2a) and a toothed head (2b); the latter can be exchanged easily when worn or broken.
These impact hammer assemblies swivel to and fro on shaft (3) due to their hammering
action. Springs are attached to them in such a way that the hammers are made to work
against each other's movements at the same time absorbing their impacts.
[0014] The discs (1) are held from rotating on shaft (7) with machine keys (5), and are
kept at a distance from each other with metal spacers (8); this allows dismantling
in case of breakage. The shaft (7) runs on two self lubricating bearings (9), with
the corresponding fixing elements. The sprocket (10) is secured positively on the
shaft but in such a way that dismantling is possible.
[0015] The assembly described makes up the main part of the machine tool head; it is protected
from accidental manipulation by a shield (11), which is fitted so that it may swivel.
Due to a spring (12) the shield is always held in place covering the impact hammers
(2) whether or not the machine is being used; shield swivelling is limited by stops.
[0016] The head assembly is joined to the motor housing (14) (Fig. 1 and Fig. 2), through
a tubular metal structure (15), which makes the machine tool lightweight. A bar (31)
allows the machine tool to be placed on the floor without the hammers coming into
contact with it. The tubular structure has an articulated joint which allows it to
swivel; the swivelling is limited by stops (16) and is always upward from the horizontal
plane. This articulated joint is fitted with a pawl that prevents it from moving from
the different positions it can adopt. The swivelling is carried out manually and the
spring (18) avoids sharp movements.
[0017] The motor (4) is fitted inside the housing. It incorporates a torque limiter which
absorbs overloads caused by jamming when in use; this is a safety mechanism.
[0018] The power unit can be either an internal combustion engine or an electric motor.
In any case it must have a variable speed control so that the power is transmitted
smoothly to the transmission components, sprockets and belt.
[0019] On the output shaft of the motor there is a sprocket (19). Power transmission from
the motor to the impact tools should be by means of sprockets and toothed belt for
quiet and maintenance free operation, and high efficiency. Sprocket (19) runs on roller
bearings (20) to avoid radial overloading.
[0020] When the motor begins to turn, it transmits its movement to the sprocket (19); this
movement is controlled by the accelerator (21) located at the handle on the motor
housing. As the accelerator is progressively pressed, the movement is increased and
transmitted in turn to the sprocket; when the accelerator is released, the motor stops
transmitting its power to the head assembly. To allow this function, it must incorporate
a variable speed drive.
[0021] This start up and transmission system is ideal because there are occasions when,
on the one hand, it is not necessary for the impact tools (2) to be working, for example,
when changing the machine tool to another position, or changing to another work area,
etc., but, on the other hand, it is necessary for the motor to be working. This avoids
repeated starting and stopping. It is also a safety aid against accidents since, when
the accelerator (24) is released, the impact hammers stop.
[0022] The turning movement of the motor is transmitted to the sprocket (19) which in turn
transmits the movement to the other sprocket (10) by means of a transmission belt
(22). The sprockets are of different diameter to achieve the necessary power to work
the machine tool' s impact hammers. The transmission belt has a safety cover to avoid
accidental manipulation during operation. It also has a tensioner wheel (24) to adjust
tension and facilitate assembly and removal.
[0023] The shaft in the head receives a rotating movement, which is transmitted to the hammers,
or impact tools. As the machine tool is brought nearer to the wall surface, the shield
(11) swivels to uncover the hammers. Their turning movement produces a continuous
action on the wall or floor surface that causes material to fall away. The penetration
depth of the hammers is limited by stops (35), which consist of two rods which can
be adjusted by means of two threaded bolts. Wheels are incorporated on the ends to
assist movement along the work area.
[0024] The machine tool has a water spray device, fitted to the shield, which aims water
directly over the area being removed by the hammers, in order to eliminate the dust
which is produced while in operation. Water supply is controlled by a trigger on the
handle (28), which is connected to a water outlet by means of a quick fit system (34);
the tubing up to the spray jets should be flexible, especially at the machine tool
articulations.
[0025] The surface stripping machine tool incorporates two handles (28) and (29) to grip
with hands and a strap (30) to hang on shoulder. Handle (28) can be adjusted at different
positions by means of slots (33).
[0026] From the description and the examination of the diagrams it is possible to see the
advantages the stripping machine tool provides with respect to other systems.
[0027] The materials used in the manufacture of the components for the stripping machine
tool, their shape and dimensions, will not alter the invention, provided that its
essential features are not affected.
BRIEF DESCRIPTION OF DRAWINGS
[0028] The attached drawings, which are referred to in the invention description, represent
an example of a practical design for the surface stripping machine tool.
[0029] Fig.1 represents a general plan view of the machine tool and a detail of the articulated
joint with pawl, stops and springs, at the connecting point between the metal structure
and the motor housing; Fig.2 represents a right side elevation showing the transmission
system with sprockets and toothed belt; Fig.3 represents a left side elevation with
a cross sectional view of the head and a detailed view of the water spray system which
projects water over the area being removed by the impact hammers; Fig.4 represents
a detailed view of the machine tool head, plan and side elevation showing the arrangement
of its elements; Fig.5 represents a detailed view of the arrangement of the impact
hammers on the discs, plan and side elevation with partial cross sectional view.
1. MACHINE TOOL FOR STRIPPING PLASTER AND TILES OFF HORIZONTAL AND VERTICAL SURFACES
with special characteristic features, as shown in Fig. 4 and Fig. 5, in that it has
a rotating system of toothed impact hammers, each of which consisting of two pieces,
body (2a) and head (2b), which can be easily separated for replacement in case of
wear or breakage of the toothed head. The toothed impact hammers are attached to metal
discs (1) by means of a shaft; the impact hammers within the same disc are also attached
to each other by means of springs (6). Each disc assembly is fitted onto a shaft (7),
which transmits its rotating movement to the assemblies.
2. MACHINE TOOL FOR STRIPPING according to claim 1, with special characteristic features,
as shown in Fig 5, in that it has a system for attaching the impact hammers to each
other by means of springs, in such a way that during operation the blows the impact
hammers are subjected to are absorbed by these springs, at the same time opposing
the oscillating motion of the impact hammers on their shafts (3), which attach them
to the metal discs (1).
3. MACHINE TOOL FOR STRIPPING according to claims 1 and 2 with special characteristic
features, as shown in Fig. 4, in that it has a water spray system by means of spray
jets (32), which aim directly at the area being removed by the toothed hammers, in
order to eliminate the dust produced while in operation.
4. MACHINE TOOL FOR STRIPPING according to claims 1,2 and 3 with special characteristic
features, as shown in Figs. 1,2 and 3, in that it has a head section where the impact
mechanism is housed, a base section (14) where the motor is housed, and a structure
(15) that joins the two. The structure swivels where it joins the motor housing; the
swivelling may reach a predetermined angle as from the horizontal plane and always
in a positive direction, limited by stops and a pawl that maintains it in the desired
position.