U.S. patent application number 16/960442 was filed with the patent office on 2020-11-05 for floor grinding machine.
The applicant listed for this patent is SCANMASKIN SVERIGE AB. Invention is credited to MARTIN PERSSON.
Application Number | 20200346315 16/960442 |
Document ID | / |
Family ID | 1000004959673 |
Filed Date | 2020-11-05 |
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United States Patent
Application |
20200346315 |
Kind Code |
A1 |
PERSSON; MARTIN |
November 5, 2020 |
FLOOR GRINDING MACHINE
Abstract
A floor grinding machine includes a supporting frame, a grinding
unit attached to the supporting frame, and a drive unit connected
to the grinding unit. The grinding unit includes an upper housing,
a lower housing rotatably arranged in relation to the upper
housing, and a planetary drive system connected to the drive unit.
The upper housing includes a first side wall. The lower housing
includes a bottom plate and a second side wall. One or more
grinding disks adapted for holding a tool are rotatably attached to
the bottom plate. The planetary drive system is arranged to rotate
the lower housing and the one or more grinding disks. The first
side wall at least partly overlaps the second side wall. A gap is
formed in a radial direction between the first side wall and the
second side wall, and a sealing element is arranged in the gap.
Inventors: |
PERSSON; MARTIN; (Onsala,
SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SCANMASKIN SVERIGE AB |
Lindome |
|
SE |
|
|
Family ID: |
1000004959673 |
Appl. No.: |
16/960442 |
Filed: |
January 15, 2019 |
PCT Filed: |
January 15, 2019 |
PCT NO: |
PCT/SE2019/050021 |
371 Date: |
July 7, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B24B 7/186 20130101 |
International
Class: |
B24B 7/18 20060101
B24B007/18 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 18, 2018 |
SE |
1850052-0 |
Claims
1. A floor grinding machine comprising a supporting frame, a
grinding unit attached to the supporting frame, and a drive unit
connected to the grinding unit, where the grinding unit comprises
an upper housing, a lower housing rotatably arranged in relation to
the upper housing, and a planetary drive system connected to the
drive unit, where the upper housing comprises a top plate and a
first side wall projecting downwards from the top plate in an axial
direction (AX), wherein the lower housing comprises a bottom plate
and a second side wall, where one or more grinding disks adapted
for holding a tool are rotatably attached to the bottom plate,
where the planetary drive system is arranged to rotate the lower
housing and the one or more grinding disks respectively, where the
first side wall is coaxially arranged in relation to the second
side wall, and where the first side wall in the axial direction
(AX) at least partly is overlapping the second side wall, and
wherein a gap is formed in a radial direction (R) between the first
side wall and the second side wall, and where a sealing element is
arranged in the gap.
2. A floor grinding machine according to claim 1, wherein the gap
is formed in the radial direction (R) between an inner surface of
the first side wall and an outer surface of the second side
wall.
3. A floor grinding machine according to claim 2, wherein the
second side wall is projecting upwards and/or downwards from the
bottom plate in the axial direction (AX), and where the gap is
formed in the radial direction (R) between the inner surface of the
first side wall and the outer surface of the second side wall.
4. A f loor grinding machine according to claim 2, wherein the
sealing element is arranged along peripheries of the inner surface
and the outer surface respectively, and where an outer edge of the
sealing element is attached to the inner surface of the first side
wall, wherein the outer surface of the second side wall is slidably
in contact with an inner edge of the sealing element.
5. A floor grinding machine according claim 2, wherein the sealing
element is releasably attached to the inner surface of the first
side wall, and arranged to be adjustably positioned in the axial
direction (AX) along the inner surface of the first side wall.
6. A f loor grinding machine according to claim 2, wherein the
inner surface of the first side wall has an essentially circular
cross-sectional shape around an axis (A) extending in the axial
direction (AX) and the outer surface of the second side wall has an
essentially circular cross-sectional shape around the axis (A)
extending in the axial direction (AX).
7. A floor grinding machine according to claim 1, wherein the top
plate and the first side wall of the upper housing are forming a
first space, where the lower housing at least partly is arranged
inside the first space of the upper housing
8. A floor grinding machine according to claim 1, wherein the
second side wall is projecting upwards from the bottom plate in the
axial direction (AX), and where the gap is formed in the radial
direction (R) between an inner surface of the second side wall and
an outer surface of the first side wall.
9. A floor grinding machine according to claim 8, wherein the inner
surface of the second side wall has an essentially circular
cross-sectional shape around an axis (A) extending in the axial
direction (AX) and the outer surface of the first side wall has an
essentially circular cross-sectional shape around the axis (A)
extending in the axial direction (AX).
10. A floor grinding machine according to claim 8, wherein the
bottom plate and the second side wall of the lower housing are
forming a second space (19), where the upper housing at least
partly is arranged inside the second space (19) of the lower
housing.
11. A floor grinding machine according to claim 1, wherein the
upper housing, the lower housing, and the sealing element are
forming a sealed volume of the grinding unit (3), where the sealing
element is preventing contaminants from entering the sealed
volume.
12. A floor grinding machine according to claim 1, wherein a drive
shaft of the planetary drive system is releasably connected to the
drive unit via a drive coupling, and where the drive shaft is
passing through an opening in the upper housing.
13. A floor grinding machine according to claim 1, wherein the
planetary drive system comprises a belt drive unit arranged on the
lower housing connected to the drive unit, where the belt drive
unit is arranged to rotate the lower housing in relation to the
upper housing, and to rotate the one or more grinding disks in
relation to the lower housing.
14. A floor grinding machine according to claim 13, wherein the
belt drive unit comprises a drive belt, where each of the one or
more grinding disks is connected to a pulley, where a rotational
movement is transferred from the drive unit to the one or more
grinding disks via the drive belt and the one or more pulleys.
15. A floor grinding machine according to claim 13, wherein the
planetary drive system comprises a ring gear arranged on an inner
surface of the first side w all of the upper housing, where the
ring gear is interacting with at least one pinion rotatably
connected to the lower housing, and where the at least one pinion
is rotated by the belt drive unit.
16. A floor grinding machine according to claim 1, wherein the
grinding unit is pivotally attached to the supporting frame about a
lateral axis (L).
17. A floor grinding machine according to claim 1, wherein the
upper housing is non-rotatably arranged in relation to the
supporting frame.
18. A floor grinding machine according to claim 1, wherein the
upper housing and/or the lower housing are made of ductile cast
iron.
19. A floor grinding machine according to claim 1, wherein the
sealing element is a radial seal having a continuous configuration
made of an elastomeric material, such as nitrile butadiene rubber
(NBR) or carboxylated nitrile rubber (XNBR).
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a U.S. National Stage of
PCT/SE2019/050021 filed on Jan. 15, 2019, which claims priority to
Swedish Application No. 1850052-0, filed Jan. 18, 2018, each of
which are incorporated herein by reference in their entirety.
TECHNICAL FIELD
[0002] The present disclosure relates to a floor grinding machine,
and in particular to a floor grinding machine that is adapted for
grinding or polishing floor surfaces, where the floor grinding
machine comprises a supporting frame, a grinding unit connected to
the supporting frame, and a drive unit connected to the grinding
unit.
BACKGROUND
[0003] Floor grinding machines are commonly used for grinding or
polishing floor surfaces, for example when there is a need to even
out the floor surface or if a floor structure needs to be
renovated. The floor grinding machine will when grinding the floor
provide an even and smooth structure to the floor surface and the
floor surface may be further treated or glossed after the grinding
process if desired. Different types of grinding tools may be
attached to the floor grinding machine in order to meet the demands
on a desired surface structure of the floor.
[0004] Floor grinding machines that especially are suitable for
grinding or polishing floor surfaces of concrete, stone, and
concrete-like or stone-like materials, such as for example
terrazzo, concrete of different qualities, limestone, sandstone,
marble, slate, or granite, are often designed with a supporting
frame, a grinding unit attached to the supporting frame, and a
drive unit connected to the grinding unit. The grinding unit may be
equipped with a drive system, such as a planetary drive system
arranged within a housing structure or grinding head. One or more
grinding disks are rotatably attached to the housing structure and
are arranged to rotate in relation to the housing structure. The
housing structure is adapted to rotate in relation to the
supporting frame of the floor grinding machine, and the grinding
disks and the housing structure are driven by the drive system.
[0005] During the grinding process, particles, water or other
contaminants from the surface structure will easily penetrate
different parts of the floor grinding machine and these
contaminants may have a negative impact on the wear of the machine
and parts of the machine. Especially the drive system needs to be
protected from the contaminants, and therefore the rotating housing
structure or grinding head may be designed as a sealed rotating
unit preventing the contaminants from entering the drive system
housed within the housing structure. Floor grinding machines and
the machine parts are often very heavy in construction, and floor
grinding machines of this type often weigh up to 500 kg depending
on the model and size of the machine, and certain models could even
weigh more than 700 kg. The servicing process of the machine and
the cleaning of machine parts may therefore be a complicated and
time consuming operation, especially when the rotating housing
structure or grinding head needs to be removed from the grinding
machine, or if the housing structure needs to be disassembled and
assembled for servicing the drive system.
[0006] While rotating housing structures or grinding heads as
described above are commonly used, there is a need to provide an
improved and simplified floor grinding machine structure that would
simplify the processes of assembling, disassembling, cleaning and
servicing of the floor grinding machine, also for heavier machine
models.
SUMMARY
[0007] An object of the present disclosure is to provide a floor
grinding machine where the previously mentioned problems are
avoided. This object is at least partly achieved by the features of
the independent claims. The dependent claims contain further
developments of the floor grinding machine.
[0008] The disclosure concerns a floor grinding machine comprising
a supporting frame, a grinding unit attached to the supporting
frame, and a drive unit connected to the grinding unit. The
grinding unit comprises an upper housing, a lower housing rotatably
arranged in relation to the upper housing, and a planetary drive
system connected to the drive unit, where the upper housing
comprises a top plate and a first side wall projecting downwards
from the top plate in an axial direction. The lower housing
comprises a bottom plate and a second side wall, where one or more
grinding disks adapted for holding a tool are rotatably attached to
the bottom plate, where the planetary drive system is arranged to
rotate the lower housing and the one or more grinding disks
respectively. The first side wall is coaxially arranged in relation
to the second side wall, and the first side wall is in the axial
direction at least partly overlapping the second side wall. A gap
is formed in a radial direction between the first side wall and the
second side wall, and a sealing element is arranged in the gap.
[0009] A floor grinding machine having a grinding unit with this
configuration is providing a simple design of the grinding unit
with a tight and sealed grinding unit construction preventing
particles, water or other contaminants from the surface structure
to penetrate different parts of the grinding unit. This will
prevent that the contaminants are having a negative impact on the
wear of the machine and parts of the machine. Also, the maintenance
and servicing process of the machine as well as the cleaning
process of the machine and machine parts can be made much more fast
and convenient for the service personnel, since with this
construction of the grinding unit, the disassembling and assembling
of the grinding unit is possible to make much more efficient.
Further, with this construction, an improved and simplified floor
grinding machine structure is achieved that simplifies the
processes of assembling, disassembling, cleaning and servicing the
floor grinding machine, also for heavier machine models.
[0010] According to an aspect of the disclosure, the gap is formed
in the radial direction between an inner surface of the first side
wall and an outer surface of the second side wall. The gap is in
this way forming a suitable area for the sealing element, where the
sealing element is forming a tight seal between the upper housing
and the lower housing. The lower housing can with this construction
efficiently rotate in relation to the upper housing without major
frictional forces.
[0011] According to another aspect of the disclosure, the second
side wall is projecting upwards and/or downwards from the bottom
plate in the axial direction, and the gap is formed in the radial
direction between an inner surface of the first side wall and an
outer surface of the second side wall. With this configuration, the
sealing element can be efficiently arranged between the side walls
providing a tight seal between the upper housing and the lower
housing.
[0012] According to another aspect of the disclosure, the sealing
element is arranged along peripheries of the inner surface and the
outer surface respectively, and an outer edge of the sealing
element is attached to the inner surface of the first side wall,
wherein the outer surface of the second side wall is slidably in
contact with an inner edge of the sealing element. The sealing
element is attached to the upper housing and when the lower housing
is rotating in relation to the upper housing the sealing element is
sliding against the lower housing and is establishing a tight seal
between the side walls.
[0013] According to a further aspect of the disclosure, the sealing
element is releasably attached to the inner surface of the first
side wall, and arranged to be adjustably positioned in the axial
direction along the inner surface of the first side wall. A
repositioning of the sealing element may be desired if the part of
the outer surface of the lower housing that is sliding against the
sealing element becomes worn. Through the repositioning of the
sealing element in the axial direction a tight seal between the
upper housing and the lower housing can be maintained even if a
part of the outer surface of the lower housing is worn.
[0014] According to another aspect of the disclosure, the inner
surface of the first side wall has an essentially circular
cross-sectional shape around an axis extending in the axial
direction and the outer surface of the second side wall has an
essentially circular cross-sectional shape around the axis
extending in the axial direction. With this geometry, the gap is
ring-shaped or has an annular shape so that the sealing element can
be made with a simple and efficient sealing construction.
[0015] According to another aspect of the disclosure, the top plate
and the first side wall of the upper housing are forming a first
space, where the lower housing at least partly is arranged inside
the first space of the upper housing. Since the lower housing at
least partly is arranged inside the first space a compact grinding
unit is achieved.
[0016] According to a further aspect of the disclosure, the second
side wall is projecting upwards from the bottom plate in the axial
direction, and where the gap is formed in the radial direction
between an inner surface of the second side wall and an outer
surface of the first side wall. With this configuration, the
sealing element can in another embodiment be efficiently arranged
between the side walls providing a tight seal between the upper
housing and the lower housing.
[0017] According to a further aspect of the disclosure, the inner
surface of the second side wall has an essentially circular
cross-sectional shape around an axis extending in the axial
direction and the outer surface of the first side wall has an
essentially circular cross-sectional shape around the axis
extending in the axial direction. Also, with this configuration,
the gap is ring-shaped or has an annular shape so that the sealing
element can be made with a simple and efficient sealing
construction.
[0018] According to a further aspect of the disclosure, the bottom
plate and the second side wall of the lower housing are forming a
second space, where the upper housing at least partly is arranged
inside the second space of the lower housing. Since the upper
housing at least partly is arranged inside the second space a
compact grinding unit is achieved.
[0019] According to a further aspect of the disclosure, the upper
housing, the lower housing, and the sealing element are forming a
sealed volume of the grinding unit, where the sealing element is
preventing contaminants from entering the sealed volume. In this
way the rotating lower housing is not designed in a traditional way
as a sealed rotating unit. Instead, the rotating lower housing has
an open structure and the contaminants are prevented from entering
the drive system housed within the grinding unit through the
configuration with the sealed volume established by the upper
housing, the sealing element and the rotating lower housing. This
structure is providing a grinding unit adapted for easy maintenance
and service. The lower housing has an open structural configuration
upwards in the axial direction. This means that the rotating lower
housing is not covered with a lid or similar covering structure
that is rotating with the lower housing. In this way the rotating
lower housing is designed in a more simple and convenient open
structured way that makes maintenance and servicing processes of
the machine as well as the cleaning process of the machine and
machine parts much faster and more convenient for service
personnel.
[0020] According to another aspect of the disclosure, a drive shaft
of the planetary drive system is releasably connected to the drive
unit via a drive coupling, and where the drive shaft is passing
through an opening in the upper housing. With this arrangement, the
lower housing can be removed from the grinding unit structure in a
fast and convenient way.
[0021] According to a further aspect of the disclosure, the
planetary drive system comprises a belt drive unit arranged on the
lower housing connected to the drive unit, where the belt drive
unit is arranged to rotate the lower housing in relation to the
upper housing, and to rotate the one or more grinding disks in
relation to the lower housing. The planetary drive system is
providing a simple, reliable and efficient driving of the grinding
unit through the belt drive unit. The drive system can be made in a
compact format suitable for being arranged on the lower housing
structure so that the drive system is arranged inside the grinding
unit, where it is prevented from coming into contact with water,
particles or other contaminants.
[0022] According to other aspects of the disclosure, the belt drive
unit comprises a drive belt, where each of the one or more grinding
disks is connected to a pulley, where a rotational movement is
transferred from the drive unit to the one or more grinding disks
via the drive belt and the one or more pulleys. Further, the
planetary drive system comprises a ring gear arranged on the inner
surface of the upper housing, where the ring gear is interacting
with at least one pinion rotatably connected to the lower housing,
and where the at least one pinion is rotated by the belt drive
unit. These features provide a simple, reliable and efficient
construction of the planetary drive system.
[0023] According to other aspects of the disclosure, the grinding
unit is pivotally attached to the supporting frame about a lateral
axis, and further the upper housing is non-rotatably arranged in
relation to the supporting frame, which is providing a flexible and
stable construction of the grinding machine.
[0024] According to another aspect of the disclosure, the upper
housing and/or the lower housing are made of ductile cast iron.
Ductile cast iron will provide a strong and heavy construction to
the upper and lower housings, and the design of the housings can be
precision made through a die casting process.
[0025] According to a further aspect of the disclosure, the sealing
element is a radial seal having a continuous configuration made of
an elastomeric material, such as nitrile butadiene rubber (NBR) or
carboxylated nitrile rubber (XNBR). The use of a continuous
configuration, where the sealing element can be made of a single
piece of material in an elastomeric material will provide a tight
seal between the upper housing and the lower housing.
BRIEF DESCRIPTION OF DRAWINGS
[0026] The disclosure will be described in greater detail in the
following, with reference to the attached drawings, in which
[0027] FIG. 1a shows schematically, in a perspective view from
above a floor grinding machine according to the disclosure,
[0028] FIG. 1b shows schematically, in a side view a floor grinding
machine according to the disclosure,
[0029] FIG. 1c shows schematically, in view from below a floor
grinding machine according to the disclosure,
[0030] FIG. 2a-b show schematically, in perspective views a
grinding unit and a cross-section of the grinding unit of the floor
grinding machine according to the disclosure
[0031] FIG. 2c-d show schematically, in perspective views
cross-sections of a part of the grinding unit according to the
disclosure, with alternative embodiments of a sealing element,
[0032] FIG. 3 shows schematically, in a side view a cross-section
of the grinding unit according to the disclosure,
[0033] FIG. 4a-b show schematically, in a perspective view from
above and a view from above a lower housing and a planetary drive
system of the grinding unit according to the disclosure, and
[0034] FIG. 5a-c show schematically, inside view cross-sections of
the grinding unit according to different embodiments of the
disclosure.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0035] Various aspects of the disclosure will hereinafter be
described in conjunction with the appended drawings to illustrate
and not to limit the disclosure, wherein like designations denote
like elements, and variations of the described aspects are not
restricted to the specifically shown embodiments, but are
applicable on other variations of the disclosure.
[0036] In FIGS. 1a-c, a floor grinding machine 1 that is used for
grinding or polishing floor surfaces is schematically shown. Floor
grinding machines are suitable for example when there is a need to
even out floor surfaces or if a floor structure needs to be
renovated. The grinding machine 1 will during operation grind the
floor surface into a desired surface structure, and the grinding
operation may be optimized for a certain floor surface material by
using specific grinding tools suitable for the specific floor
surface material. The floor surface may be further treated or
glossed, and different types of grinding or polishing tools may be
attached to the floor grinding machine 1 in order to meet the
demands on a desired floor surface structure. The grinding machine
1 may be used for grinding or polishing floor surfaces of concrete,
stone, and concrete-like or stone-like materials, such as for
example terrazzo, concrete of different qualities, limestone,
sandstone, marble, slate, or granite.
[0037] The floor grinding machine 1 comprises a supporting frame 2
designed as a conventional frame structure for holding other
components of the grinding machine 1. The supporting frame 2 is for
example made of steel or other suitable materials such as aluminum,
composite materials or a combination of different materials. The
supporting frame 2 may be provided with a pair of rear wheels 31
arranged in a rear part of the floor grinding machine, and one or
more front wheels 32 arranged in a front part of the floor grinding
machine 1, where the wheels may be attached to the supporting frame
2 in a suitable conventional way. The floor grinding machine 1 may
be manually pushed during the grinding operation or alternatively
driven by a drive system arranged to drive one or more of the
wheels. A handle 33 may also be attached to the supporting frame 2
in a rear part of the floor grinding machine 1, and the handle 33
is used for pushing, pulling or maneuvering the floor grinding
machine 1 in different directions. The handle 33 may be arranged so
that it can be pivoted in different positions. The grinding machine
1 may as an alternative be driven by an automated drive system that
is enabling a stable and smooth grinding function. A radio
controlled system can be used for controlling the motion and
grinding speed of the floor grinding machine 1, and a remote
control may be connected to the drive system to allow an operator
to move the machine in any desired direction. In this way the floor
grinding machine 1 can be maneuvered with high precision for
example in tight areas.
[0038] The rear wheels 31 may be arranged so that they are
displaceable in a longitudinal direction LO in relation the
supporting frame 2. The rear wheels 31 may be suspended on rear
wheel shafts 36 extending in a lateral direction LA in relation to
the supporting frame 2 in a way so that they can be adjusted in
different positions in the longitudinal direction LO. In this way
the center of gravity of the floor grinding machine can be shifted
forwards and backwards in order to provide a suitable grinding
pressure on the floor structure during the grinding operation. The
more rearward the rear wheels 31 are positioned in relation to the
supporting frame 2 in the longitudinal direction LO, the more the
pressure on the front part of the grinding machine will increase.
The rear wheels 31 may be driven by a suitable driving mechanism,
and as an option they may be individually driven so that a
direction of travel of the machine may be controlled.
[0039] As shown in FIGS. 1a-c, the floor grinding machine is
provided with a front wheel structure with one front wheel 32,
which is held in position in relation to the supporting frame 2
with a front wheel bracket 37. The front wheel 32 may be arranged
as a swivel wheel or caster for easy maneuvering of the floor
grinding machine 1 during transport or grinding. The front wheel 32
may be detachable from the frame structure 2 so that during the
grinding process, the floor grinding machine 1 can be operated
without the front wheel 32 if desired. As an alternative the front
wheel 32 and the front wheel bracket 37 holding the front wheel 32
may be arranged so that the front wheel structure can be pivoted in
different positions about a front wheel bracket axis 38 extending
in the lateral direction LA. In this way, the front wheel structure
may be pivoted so that the front wheel 32 is not in contact with
the floor during the grinding operation, or alternatively the front
wheel structure is held in a position in relation to the floor
structure where the front wheel 32 is in contact with the floor so
that a desired grinding pressure is achieved during the grinding
operation. The front wheel structure may also be designed so that
the grinding pressure can be controlled and adjusted during the
grinding operation through pivoting the front wheel bracket 37 in
relation to the frame structure 2. In this way, when the front
wheel 32 is adjusted in a direction downwards so that the front
part of the supporting frame 2 is moved upwards from the floor
surface, the grinding pressure will decrease, and when the front
wheel 32 is adjusted in a direction upwards, the grinding pressure
will increase.
[0040] As further shown in FIGS. 1a and 1b, a housing unit 34 is
attached to the frame structure 2. The housing unit 34 may for
example comprise an electronic or computerized control system of
the floor grinding machine 1 with associated controls and displays.
The housing unit 34 may further comprise a water tank and necessary
electrical components and connections.
[0041] A grinding unit 3 is attached to the supporting frame 2, and
positioned in front of the rear wheels 31. The grinding unit 3 is
arranged for grinding or polishing the floor surface when the floor
grinding machine 1 moves along the floor and the grinding unit 3 is
providing an even and smooth structure to the floor surface when
the floor grinding machine is being operated. The grinding unit 3
may be pivotally attached to or suspended in relation to the
supporting frame 2 so that the grinding unit 3 will have a position
that is essentially parallel to the floor surface during the
grinding operation. The grinding unit 3 may for example be attached
to the frame structure 2 with bolts 35 or similar arrangements so
that the grinding unit 3 can be pivoted around a lateral axis L, as
shown in FIG. 1a. The lateral axis L is extending in the lateral
direction LA in relation to the supporting frame 2 of the grinding
machine 1, as indicated in FIG. 1a. In this way, the grinding
machine 1 may typically be supported by its grinding unit 3 during
the grinding operation. Thus, the grinding machine 1 may have a
construction where the grinding unit 3 is pivotally attached to the
supporting frame 2 about the lateral axis L.
[0042] A drive unit 4 is as shown in FIGS. 1a and 1b connected to
the grinding unit 3. The drive unit 4 may be of any conventional
type, such as for example an electric motor or an internal
combustion engine. The internal combustion engine may be gas
driven, where a suitable gas for example may be propane. As an
alternative, two or more electric motors or combustion engines may
be used as the drive unit 4 instead of a single motor or engine
unit, depending on the construction and design of the floor
grinding machine 1.
[0043] As shown in FIGS. 2b, 3 and 5a-c, the grinding unit 3
comprises an upper housing 5 and a lower housing 6, and the lower
housing 6 is rotatably arranged in relation to the upper housing 5.
As shown for example in FIGS. 2b and 5a-c, the lower housing 6 is
arranged so that the lower housing 6 rotates about an axis A
extending in an axial direction AX of the grinding unit 3 during
the grinding operation. The upper housing 5 is non-rotatably
arranged in relation to the supporting frame 2. In this way the
upper housing 5 is arranged so that it is not rotating about the
axis A extending in the axial direction AX of the grinding unit 3
during the grinding operation. However, as described above, the
grinding unit 3 may pivot about the lateral axis L in relation to
the supporting frame 2. As further shown in the figures, a radial
direction R of the grinding unit 3 is defined as a direction which
is perpendicular to or essentially perpendicular to the axial
direction AX of the grinding unit 3. The grinding unit 3 as such
has an extension both in the axial direction AX and in the radial
direction R as will be further described.
[0044] The grinding unit 3 further comprises a planetary drive
system 7, which is connected to the drive unit 4. The planetary
drive system 7 may be a conventional planetary drive system used
for floor grinding machines. During operation of the grinding
machine, the drive unit 4 is connected to the planetary drive
system 7 so that a rotary motion of the drive unit 4 is transferred
to the planetary drive system 7. The planetary drive system 7 is
arranged to rotate the lower housing 6 in relation to the upper
housing 5, as will be further described below. The drive unit 4 may
be provided with an outgoing shaft that is operably connected to
the planetary drive system 7 of the grinding unit 3. The outgoing
shaft of the drive unit 4 may be directly connected to a drive
shaft 20 of the planetary drive system 7 or indirectly connected to
the drive shaft 20 via a gear unit, depending on the construction
of the floor grinding machine. As shown in the figures, the drive
shaft 20 of the planetary drive system 7 is extending essentially
in the axial direction AX and the drive shaft 20 is arranged to
rotate about the axis A. The drive unit 4 may be attached to the
upper housing 5 of the grinding unit 3 with screws, bolts or other
suitable fastening means.
[0045] The upper housing 5 comprises a top plate 8 and a first side
wall 9, as shown in FIGS. 2b, 3 and 5a-c. The first side wall 9 is
projecting in a direction downwards from the top plate 8 in the
axial direction AX of the grinding unit 3. The top plate 8 may, as
shown in FIGS. 5a-c, have a flat cross-sectional configuration or
shape when viewed from the side. However other suitable
cross-sectional configurations or shapes are also possible, such as
for example curved or stepped. In FIG. 2b, a stepped configuration
of the top plate 8 is shown more in detail. The top plate 8 as well
as the upper housing 5 may have an essentially circular
configuration when viewed from above or below and the top plate 8
may be provided with an outer flange 39, as shown in FIGS. 2a and
2b, to which the drive unit 4 is attached.
[0046] The first side wall 9 may extend essentially from and around
the outer periphery of the top plate 8, and the first side wall 9
may be formed into a suitable shape. As shown in FIGS. 5a-c, the
first side wall 9 may have an essentially straight cross-sectional
shape when viewed from the side. As an alternative, the first side
wall 9 may instead have a curved or stepped cross-sectional shape,
and in FIG. 2b the first side wall 9 is having a stepped
cross-sectional shape. The first side wall 9 has an inner surface
16a and an outer surface 16b.
[0047] The top plate 8 and the first side wall 9 may be arranged as
an integrated structure that is forming the upper housing 5, and
the upper housing 5 may be made of one single piece of material, or
alternatively in two or more parts that are assembled into an
integrated structure. A suitable material for the upper housing 5
is for example ductile cast iron. An upper housing 5 made of
ductile cast iron will provide a strong and heavy construction, and
the design of the upper housing 5 can be precision made through a
suitable die casting process. Alternatively, the upper housing 5
may be made of other materials, such as for example steel, aluminum
or other metals, plastic or composite materials as well as
combinations of different materials, which material or materials
are shaped into a desired housing structure.
[0048] The lower housing 6 comprises a bottom plate 11 and a second
side wall 12. In the embodiment shown in FIGS. 2b-d, 3 and 4a-b,
the second side wall 12 may extend or project in a direction
downwards from the bottom plate 11 in the axial direction AX of the
grinding unit 3. The second side wall 12 extends essentially from
and around the outer periphery of the bottom plate 11. The side
wall 12 may also as an alternative extend both upwards and
downwards from the bottom plate 11 in the axial direction AX of the
grinding unit 3. In the embodiment shown in FIGS. 2b-d, 3 and 4a-b,
wall sections 45 are extending in a direction upwards from the
bottom plate 11.
[0049] As shown in the embodiments in FIGS. 5a and 5c, the second
side wall 12 may extend or project in a direction upwards from the
bottom plate 11 in the axial direction AX of the grinding unit 3.
In this way, the second side wall 12 extends essentially from and
around the outer periphery of the bottom plate 11. In an
alternative embodiment, as shown in FIG. 5b, the lower housing 6 is
formed by the bottom plate 11, and the second side wall 12 is in
this embodiment formed by the side edges of the bottom plate 11,
where the second side wall 12 thus extends around the outer
periphery of the bottom plate 11 and is having a dimension in the
axial direction AX of the grinding unit 3 corresponding to the
thickness of the outer part of the bottom plate 11.
[0050] The bottom plate 11 may, as shown in FIGS. 5a-c, have a flat
cross-sectional configuration or shape when viewed from the side.
However other suitable cross-sectional configurations or shapes are
also possible, such as for example curved or stepped. In for
example FIG. 2b, a stepped bottom plate 11 is shown. The bottom
plate 11 and also the lower housing 6 may have an essentially
circular configuration when viewed from above or below.
[0051] The second side wall 12 may be formed into a suitable shape
depending on the design of the grinding unit 3. As shown in FIGS.
5a-c, the second side wall 12 may have an essentially straight
cross-sectional shape when viewed from the side. As an alternative,
the second side wall 12 may instead have other suitable shapes,
such as for example a curved or stepped cross-sectional shape. In
FIGS. 2b-d a part of the second side wall 12 is having an
essentially straight cross-sectional shape arranged in the axial
direction AX of the grinding unit 3, and the second side wall 12 is
provided with a radially outwards and downwards projecting edge
part 40. In the embodiments shown in FIGS. 2b, 3, 5a and 5c, the
second side wall 12 has an inner surface 17a and an outer surface
17b. In the embodiment shown in FIG. 5b, the second side wall has
an outer surface 17b.
[0052] The bottom plate 11 and the second side wall 12 may be
arranged as an integrated structure that is forming the lower
housing 6, and the lower housing 6 may be made of one single piece
of material, or alternatively in two or more parts that are
assembled into an integrated structure. A suitable material for the
lower housing 6 is for example ductile cast iron. A lower housing 6
made of ductile cast iron will provide a strong and heavy
construction, and the design of the lower housing 6 can be
precision made through a suitable die casting process.
Alternatively, the lower housing 6 may be made of other materials,
such as for example steel, aluminum or other metals, plastic or
composite materials as well as combinations of different materials,
which material or materials are shaped into a structure suitable
for the lower housing 6.
[0053] If a heavy construction of the grinding unit 3 is desired,
the upper housing 5 and/or the lower housing 6 may be made of
ductile cast iron. A heavy construction of the grinding unit 3 will
provide an efficient grinding of the floor surface if using
suitable grinding tools 14.
[0054] One or more grinding disks 13 adapted for holding one or
more grinding tools 14 are rotatably attached to the bottom plate
11 of the lower housing 6. The grinding disks 13 may be rotatably
attached to the bottom plate 11 in a conventional way, for example
by using suitable bearings. Each of the grinding disks 13 may be
attached to the lower part of a disk shaft 41 extending through the
bottom plate 11 in the axial direction AX of the grinding unit 3,
and the disk shafts 41 may be arranged for rotating the grinding
disks 13. The lower housing 6 may rotate in a clockwise or a
counter-clockwise direction in relation to the upper housing 5 and
the grinding disks 13 may be arranged so that they can rotate in
the opposite rotational direction to achieve a desired result when
grinding the floor structure. Alternatively, the lower housing 6
and the grinding disks 13 may rotate in the same direction. In the
embodiments shown in the figures, the grinding unit 3 has three
grinding disks 13 rotatably attached to the bottom plate 11.
However, the number of grinding disks may be varied depending on
the design of the grinding machine 1. The grinding disks 13 may be
provided with suitable holders for the tools 4 so that the tools 14
easily can be attached to and removed from the grinding disks.
[0055] The planetary drive system 7 is arranged to rotate the lower
housing 6 and the one or more grinding disks 13 respectively, where
the lower housing is rotated by the planetary drive system 7 in
relation to the upper housing 5 and the grinding disks 13 are
rotated by the planetary drive system 7 in relation to the lower
housing 6. The planetary drive system 7 may be of any conventional
type used for floor grinding machines, and a suitable drive system
for the floor grinding machine 1 will be further described
below.
[0056] The tools 14 may be in the form of plates with bonded
abrasives, where the abrasives are in the form of a
three-dimensional body comprising abrasive particles and a matrix
material. The material may for example be a polymer material or a
metallic material. As an alternative, the tools 14 may be in the
form of cutting elements that for example are suitable for removal
of glue, paint, lacquer or other surface treatment compounds from
the floor surface. During the grinding operation, the grinding unit
3 with the tools 14 will exert a certain pressure on the floor, and
as described above, the grinding pressure can be adjusted by
adjusting the rear wheels 31 and/or the front wheel 32. Different
parameters can be programmed in the grinding machine system in
order to achieve a desired result when grinding the floor surface.
Examples of parameters that can be varied is for example the
rotational speed of the lower housing 6, the rotational speed of
the grinding disks 13, the forward speed of the grinding machine
and the pressure exerted by the tools 14 on the floor surface. The
grinding machine system may be programmed so that the system
recommends the right type of parameters for a specific type of
floor surface.
[0057] The grinding unit 3 may be designed with a configuration, as
indicated in FIGS. 2b, 3 and 5a-c, so that the first side wall 9 is
coaxially arranged in relation to the second side wall 12, and
further so that the first side wall 9 in the axial direction AX at
least partly is overlapping the second side wall 12. The upper
housing 5 and the lower housing 6 may thus be positioned in an
overlapping manner in relation to each other in the axial direction
AX so that the first side wall 9 is coaxially arranged in relation
to the second side wall 12 about the axis A extending in the axial
direction AX of the grinding unit 3. In this way a gap 15 is formed
in a radial direction R of the grinding unit 3 between the first
side wall 9 and the second side wall 12, and as shown in the
figures, the gap 15 is formed in the overlapping region between the
first side wall 9 and the second side wall 12, where the side walls
are having different diameters. When viewed from below or above,
the gap 15 is ring-shaped or has an annular cross-sectional shape
around the axis A that extends between the first side wall 9 and
the second side wall 12.
[0058] In FIGS. 2b-d, 3, 4a-b an embodiment of the grinding unit 3
is shown, where the second side wall 12 is projecting in a
direction downwards from the bottom plate 11 in the axial direction
AX. In FIG. 5a, an embodiment of the grinding machine 1 is shown,
where the second side wall 12 is projecting in a direction upwards
from the bottom plate 11 in the axial direction AX. In FIG. 5a, the
grinding unit 3 is only schematically shown in a cross-sectional
view without the grinding disks 13 to better illustrate the
position of the upper housing 5 in relation to the lower housing 6.
In these embodiments, the upper housing 5 is arranged in relation
to the lower housing 6 so that the first side wall 9 is coaxially
arranged in relation to the second side wall 12. The first side
wall 9 is in the axial direction AX partly overlapping the second
side wall 12. The gap 15 is formed in the radial direction R
between the inner surface 16a of the first side wall 9 and the
outer surface 17b of the second side wall 12. The inner surface 16a
of the first side wall 9 has an essentially circular
cross-sectional shape around the axis A and the outer surface 17b
of the second side wall 12 has an essentially circular
cross-sectional shape around the axis A, and in this way the lower
housing 6 can rotate in relation to the upper housing 5 with an
essentially constant gap 15 in the radial direction R and with an
essentially constant overlap in the axial direction AX. The top
plate 8 and the first side wall 9 of the upper housing 5 are
forming a first space 10, and due to the overlapping relationship
between the upper housing 5 and the lower housing 6 in the axial
direction AX the lower housing 6 is at least partly arranged inside
the first space 10 of the upper housing 5.
[0059] In FIG. 5b, another embodiment of the grinding machine 1 is
shown, where the lower housing 6 is formed by the bottom plate 11,
and the second side wall 12 is in this embodiment formed by the
side edges of the bottom plate 11. The second side wall 12 thus
extends around the outer periphery of the bottom plate 11 and is
having a dimension in the axial direction AX of the grinding unit 3
corresponding to the thickness of the outer part of the bottom
plate 11. The upper housing 5 is arranged in relation to the lower
housing 6 so that the first side wall 9 is coaxially arranged in
relation to the second side wall 12. The first side wall 9 is in
the axial direction AX overlapping the second side wall 12. In this
embodiment, the gap 15 is formed in the radial direction R between
the inner surface 16a of the first side wall 9 and the outer
surface 17b of the second side wall 12. In FIG. 5b, the grinding
unit 3 is only schematically shown in a cross-sectional view
without the grinding disks to better illustrate the position of the
upper housing 5 in relation to the lower housing 6. The inner
surface 16a of the first side wall 9 has an essentially circular
cross-sectional shape around the axis A and the outer surface 17b
of the second side wall 12 has an essentially circular
cross-sectional shape around the axis A, and in this way the lower
housing 6 can rotate in relation to the upper housing 5 with an
essentially constant gap 15 in the radial direction R and with an
essentially constant overlap in the axial direction AX. As shown in
FIG. 5b, the top plate 8 and the first side wall 9 of the upper
housing 5 are forming a first space 10, and due to the overlapping
relationship between the upper housing 5 and the lower housing 6 in
the axial direction AX the lower housing 6 is at least partly
arranged inside the first space 10 of the upper housing 5.
[0060] In FIG. 5c, a further embodiment of the grinding machine 1
is shown, where the second side wall 12 is projecting in a
direction upwards from the bottom plate 11 in the axial direction
AX. The upper housing 5 is arranged in relation to the lower
housing 6 so that the first side wall 9 is coaxially arranged in
relation to the second side wall 12. The first side wall 9 is in
the axial direction AX partly overlapping the second side wall 12.
In this embodiment, the gap 15 is formed in the radial direction R
between an inner surface 17a of the second side wall 12 and an
outer surface 16b of the first side wall 9. In FIG. 5c, the
grinding unit 3 is only schematically shown in a cross-sectional
view without the grinding disks to better illustrate the position
of the upper housing 5 in relation to the lower housing 6. The
inner surface 17a of the second side wall 12 has an essentially
circular cross-sectional shape around the axis A and the outer
surface 16b of the first side wall 9 has an essentially circular
cross-sectional shape around the axis A, and in this way the lower
housing 6 can rotate in relation to the upper housing 5 with an
essentially constant gap 15 in the radial direction R and with an
essentially constant overlap in the axial direction AX. As shown in
FIG. 5c, the bottom plate 11 and the second side wall 12 of the
lower housing 6 are forming a second space 19, and due to the
overlapping relationship between the upper housing 5 and the lower
housing 6 in the axial direction AX the upper housing 5 is at least
partly arranged inside the second space 19 of the lower housing
6.
[0061] In the different embodiments of the grinding machine 1, a
sealing element 18 is arranged in the gap 15. The sealing element
18 may be designed as a continuous sealing unit or element made of
one single piece of material that is covering the gap 15 and is
used for preventing particles, water or other contaminants that are
coming from the floor surface during the grinding operation from
penetrating the interior structure of the grinding unit 3, since
these contaminants may have a negative impact on the wear of the
grinding unit 3 and parts of the grinding unit 3. Especially the
planetary drive system 7 arranged inside the grinding unit 3 needs
to be protected from the contaminants, and therefore the rotating
lower housing 6 is sealed with the sealing element 18 in relation
to the upper housing 5. In this way, the contaminants are prevented
from entering the planetary drive system 7 housed within the
grinding unit 3. As an alternative, the sealing element 18 may be
instead built up of two or more pieces of material forming a
sealing structure that is arranged in the gap 15.
[0062] Through the use of the sealing element 18 arranged in the
gap 15 between the upper housing 5 and the rotating lower housing
6, the grinding unit 3 can be designed in a way where the interior
structure of the grinding unit 3 is easily accessible during
service or maintenance of the grinding machine 1. Since the floor
grinding machine 1 and the machine parts are heavy in construction,
it is desirable that the servicing process and the cleaning of the
machine parts can be achieved in a simple and fast operation.
Through the construction of the grinding unit 3 described above,
the grinding unit 3 may be designed so that it is easily
disassembled and assembled, and the lower housing 6 can be arranged
so that it is easily removed from the upper housing 5, for example
when there is a need for servicing the grinding machine 1 or the
drive system. Thus, through the construction of the grinding unit 3
a simplified floor grinding machine structure that makes the
processes of assembling, disassembling, cleaning and servicing of
the floor grinding machine 1 can be achieved.
[0063] In the embodiments shown in FIGS. 2b-d, 3, 5a-b, the sealing
element 18 is arranged in the gap 15 along the periphery of the
inner surface 16a of the first side wall 9 and along the periphery
of the outer surface 17b of the second side wall 12. An outer edge
23 of the sealing element 18 is attached to the inner surface 16a
of the first side wall 9, with for example glue or other suitable
fastening means. The sealing element 18 may be arranged as a radial
seal having a shape and dimension so that the outer edge 23 snugly
fits the periphery of the inner surface 16a of the first side wall
9, and through this arrangement the sealing element 18 is held in
place in relation to the inner surface 16a of the first side wall 9
with frictional forces. Radial seals are used between rotating and
stationary machine components or between two components in relative
motion. The sealing element 18 may be attached to the first side
wall 9 for example through press fitting. When viewed from above or
below, the sealing element 18 has a continuous configuration and is
ring-shaped or has an annular shape that fits the shape of the gap
15 between the first side wall 9 and the second side wall 12. The
outer surface 17b of the second side wall 12 is slidably in contact
with an inner edge 24 of the sealing element 18. When the lower
housing 6 is rotating in relation to the upper housing 5, the outer
edge 23 of the sealing element is attached to the inner surface 16a
of the first side wall 9 and the outer surface 17b of the second
side wall 12 is sliding against the inner edge 24 of the sealing
element 18. In this way a tight seal is established between the
upper housing 5 and the rotating lower housing 6 preventing
contaminants from entering the interior structure of the grinding
unit 3. The sealing element 18 may be shaped or profiled in
different ways depending on the design of the grinding unit 3, as
shown in FIGS. 2c-d. As shown in FIGS. 2c-d, the sealing element
may have a cross-sectional configuration that is U-shaped or
L-shaped, where the sealing element 18 is forming a radial seal
having a sealing lip, where the inner edge 24 of the sealing
element 18 is forming the sealing lip. The sealing lip is for
example made of an elastomeric or thermoplastic material. The edge
of the sealing lip that is in contact with the second side wall 12
may be formed by molding, cutting or grinding, and the sealing
element 18 is in this way arranged so that the inner edge 24 is
pressed against the outer surface 17b of the second side wall 12.
The sealing element 18 may also be arranged with two or more
sealing lips if desired. As an alternative two or more co-operating
sealing elements 18 may be used in combination, depending on the
design of the grinding unit 3. Further, the sealing element 18 may
be reinforced with steel or other suitable materials and provided
with a spring element, such as a garter spring providing radial
load, if needed. In an alternative embodiment, the inner surface 24
of the sealing element 18 may instead be attached to the outer
surface 17b of the second side wall 12 and the inner surface 16a of
the first side wall 9 is slidably in contact with the outer edge 23
of the sealing element 18. In this alternative embodiment the outer
edge 23 may be formed with one or more sealing lips as described
above. The sealing element 18 may be made of any suitable material,
such as for example an elastomeric or thermoplastic material.
Examples of materials that may be used are rubber materials, such
as natural rubber or synthetic rubber, and polyurethane. Examples
of suitable synthetic rubber materials providing good sealing
properties are nitrile rubber, such as nitrile butadiene rubber
(NBR) and carboxylated nitrile rubber (XNBR).
[0064] In the embodiment shown in FIG. 5c, the sealing element 18
is arranged in the gap 15 along the periphery of the inner surface
17a of the second side wall 12 and along the periphery of the outer
surface 16b of the first side wall 9. The outer edge 23 of the
sealing element 18 may be attached to the inner surface 17a of the
second side wall 12, with for example glue or other suitable
fastening means as described in the embodiments above, and may also
be arranged as a radial seal having a shape and dimension so that
the outer edge 23 snugly fits the periphery of the inner surface
17a of the second side wall 12, and through this arrangement the
sealing element 18 is held in place in relation to the inner
surface 17a of the second side wall 12 with frictional forces. The
outer surface 16b of the first side wall 9 is slidably in contact
with the inner edge 24 of the sealing element 18. When the lower
housing 6 is rotating in relation to the upper housing 5, the outer
edge 23 of the sealing element is attached to the inner surface 17a
of the second side wall 12 and the outer surface 16b of the first
side wall 9 is sliding against the inner edge 24 of the sealing
element 18. In this way a tight seal is established between the
upper housing 5 and the rotating lower housing 6 preventing
contaminants from entering the interior structure of the grinding
unit 3. As an alternative, the inner surface 24 of the sealing
element 18 may instead be attached to the outer surface 16b of the
first side wall 9 and the inner surface 17a of the second side wall
12 is slidably in contact with the outer edge 23 of the sealing
element 18. Also, in this embodiment, when viewed from above or
below, the sealing element 18 has a continuous configuration and is
ring-shaped or has an annular shape that fits the shape of the gap
15 between the first side wall 9 and the second side wall 12. The
sealing element 18 may be of the types and constructions described
in relation to the embodiments above.
[0065] In the embodiments shown in FIGS. 2b-d, 3 and 5a-b, the
sealing element 18 may be releasably attached to the inner surface
16a of the first side wall 9, and arranged to be adjustably
positioned in the axial direction LA along the inner surface 16a of
the first side wall 9. In this way the sealing element may be
removed and replaced with a new seal if needed, or alternatively be
repositioned or adjusted in the axial direction AX in relation to
the rotating lower housing 6. A repositioning of the sealing
element 18 may be desired if the part of the outer surface 17b of
the lower housing 6 that is sliding against the inner edge 24 of
the sealing element 18 becomes worn. Through the repositioning of
the sealing element 18 in the axial direction AX a tight seal
between the upper housing 5 and the lower housing 6 can be
maintained even if a part of the outer surface 17b of the lower
housing 6 is worn. As an alternative for the embodiments shown in
FIGS. 2b-d, 3 and 5a, the sealing element may instead be releasably
attached to the outer surface 17b of the second side wall 12 and
arranged to be adjustably positioned in the axial direction LA
along the outer surface 17b of the second side wall 12.
[0066] Also, in the embodiment shown in FIG. 5c the sealing element
18 may be releasably attached to the inner surface 17a of the
second side wall 12 and arranged to be adjustably positioned in the
axial direction LA along the inner surface 17a of the second side
wall 12. In this way the sealing element may be removed and
replaced with a new seal if needed, or alternatively be
repositioned or adjusted in the axial direction AX in relation to
the rotating lower housing 6. As an alternative for the embodiment
shown in FIG. 5c, the sealing element may instead be releasably
attached to the outer surface 16b of the first side wall 9 and
arranged to be adjustably positioned in the axial direction LA
along the outer surface 16b of the first side wall 9.
[0067] In the different embodiments described, the upper housing 5,
the lower housing 6, and the sealing element 18 are forming a
sealed volume 22 of the grinding unit 3 and the sealing element 18
is preventing contaminants from entering the sealed volume 22. The
planetary drive system 7 or parts of the planetary drive system 7
arranged within the sealed volume 22 is thus protected from the
contaminants. As further shown, the lower housing 6 has an open
structural configuration upwards in the axial direction LA. This
means that the rotating lower housing 6 is not covered with a lid
or similar covering structure that is rotating with the lower
housing 6. In this way the rotating lower housing 6 is not designed
in a traditional way as a sealed rotating unit. Instead, the
rotating lower housing 6 has an open structure and the contaminants
are prevented from entering the drive system housed within the
grinding unit 3 through the configuration with the sealed volume 22
established by the non-rotating upper housing 5, the sealing
element 18 and the rotating lower housing 6. This structure is
providing a grinding unit 3 adapted for easy maintenance or
service. A traditional sealed rotating unit is complex and heavy to
disassemble and assemble during service and maintenance.
[0068] To achieve a grinding unit 3 that is easy to assemble and
disassemble, the planetary drive system 7 is releasably connected
to the outgoing shaft of the drive unit 4 via a drive coupling 26,
where the drive coupling 26 is connecting the outgoing shaft of the
drive unit 4 and the drive shaft 20 of the planetary drive system.
The grinding unit 3 may be designed so that the drive shaft 20 of
the planetary drive system 7 is passing through an opening 21 in
the upper housing 5. If instead a gear unit is used for indirectly
connecting the drive unit 4 to the planetary drive system 7, the
gear unit may be provided with an outgoing shaft that is releasably
connecting the gear unit to the planetary drive system 7. The drive
coupling 26 may be of any suitable conventional type, where the
outgoing shaft can be released from the planetary drive unit 7 when
the lower housing 6 is removed from the upper housing 5, and again
connected to the planetary drive unit 7 when the lower housing 6 is
attached to the upper housing 5. With this arrangement, the drive
shaft 20 of the planetary drive system 7 is releasably connected to
the drive unit 4 via the drive coupling 26, and the drive shaft 20
is passing through the opening 21 in the upper housing 5.
[0069] The lower housing 6 may as shown in FIG. 2b be provided with
a hollow shaft 42. The upper housing 5 is releasably connected to
and held in position in relation to the lower housing 6 through the
hollow shaft 42 and a first bearing unit 43 connected to the hollow
shaft 42, where the first bearing unit 43 is rotatably connecting
the hollow shaft 42 of the lower housing 6 and the upper housing 5.
Through this configuration the lower housing 6 may be connected to
a rotating part of the first bearing unit 43 and the upper housing
5 may be releasably connected to a non-rotating part of the first
bearing unit 43. When the lower housing 6 is connected to the upper
housing 5, the first bearing unit 43 secures that the lower housing
6 can rotate in relation to the upper housing 5. The first bearing
unit 43 can for example be releasably connected to the upper
housing 5 with bolt, screws or other suitable fastening means for
easy maintenance or servicing of the grinding unit 3. Also the
first bearing unit 43 has a hollow configuration so that the drive
shaft 20 of the planetary drive system 7 can rotate in relation to
the upper housing 5 and the lower housing 6. The drive shaft 20 may
for example be attached to the lower housing 5 with a suitable
second bearing unit 44. Depending on the design of the grinding
unit 3, one or more further bearings may also be used for holding
the drive shaft 20 in position in relation to other components of
the grinding unit 3.
[0070] As shown in FIGS. 2b, 3 and 4a-b, the planetary drive system
7 comprises a belt drive unit 25 arranged on the lower housing 6
and the belt drive unit 25 is connected to the drive unit 4. The
belt drive unit 25 can be a conventional belt drive system and is
arranged to rotate the lower housing 6 in relation to the upper
housing 5, and also to rotate the one or more grinding disks 13 in
relation to the lower housing 6. The belt drive unit 25 comprises a
drive belt 29 that is connected to the drive shaft 20 and each of
the one or more grinding disks 13 is connected to a pulley 30. The
pulleys are arranged on the disk shafts 41 and a rotational
movement is transferred from the drive unit 4 to the one or more
grinding disks 13 via the drive shaft 20, the drive belt 29 and the
one or more pulleys 30. When the outgoing shaft of the drive unit 4
is directly or indirectly connected to the drive shaft 20 of the
planetary drive system 7 via the drive coupling 26, the drive shaft
20 can be rotatably driven by the drive unit 4. The rotational
movement of the drive shaft 20 is transferred into a rotational
movement of each of the disk shafts 41 via the drive belt 29 that
is connected to each of the pulleys 30.
[0071] As schematically shown for example in FIG. 2b, the planetary
drive system 7 further comprises a ring gear 27 arranged on the
inner surface 16a of the first side wall 9 of the upper housing 5.
The ring gear 27 is interacting with at least one pinion 28 that is
rotatably connected to the lower housing 6. The at least one pinion
28 is rotated by the belt drive unit 25. As shown in FIGS. 3 and
4a-b, the pinions 28 are attached to the disk shafts 41 and the
rotational movement of the drive shaft 20 is transferred to the
disk shafts 41 and the pinions 28 via the drive belt 29 and the
pulley 30 as described above. When the pulley 30 is rotated by the
drive belt 29, also the pinions 28 are being rotated. Through the
interaction between the at least one pinion 28 and the ring gear 27
the rotational movement of the at least one pinion 28 is
transferred into to a rotational movement of the lower housing
6.
[0072] It should be noted that the planetary drive system may have
other configurations that the one described above. The drive belt
29 may be of any suitable type and have an endless belt
configuration, such as a toothed belt drive system or a traditional
non-toothed belt drive system. The hollow shaft 42 may be provided
with suitable openings for the drive belt 29. Instead of a drive
belt system, a chain or other suitable drive means may be used.
Further, it would be possible to design the drive system so that
only one of the grinding disks 13 is directly driven by the drive
belt 29 via only one of the disk shafts 41. The disk shafts 41
could then be connected to each other via a secondary drive system,
where for example a second drive belt is used for connecting the
disk shafts 41.
[0073] The grinding unit 3 may also be provided with other sealing
members than the sealing element 18. As an example, the first
bearing unit 43 may be sealed in relation to the upper housing 5
and the lower housing 6 to secure that contaminants are not
entering the sealed volume 22.
[0074] The dimensions of the floor grinding machine 1 and the parts
of the floor grinding machine 1 may be varied depending on the size
and design of a specific grinding machine model. As a non-limiting
example and depending on the design of the grinding unit 3, when
viewed from above or below the upper housing 5 may have an outer
diameter within the range 400-1200 mm, and the lower housing 6 may
have an outer diameter within the range 400-1200 mm. The gap 15
formed in the radial direction R between the first side wall 9 and
the second side wall 12, may as a non-limiting example have an
extension in the radial direction within the range 5-40 mm, and
thus the sealing element 18 may have a thickness in the radial
direction R within the range 5-40 mm. Other dimensions are also
possible. The gap 15 may have an extension in the radial direction
R that varies in the axial direction AX, depending on the shapes of
the first side wall 9 and the second side wall 12 respectively.
[0075] It will be appreciated that the above description is merely
exemplary in nature and is not intended to limit the present
disclosure, its application or uses. While specific examples have
been described in the specification and illustrated in the
drawings, it will be understood by those of ordinary skill in the
art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the present disclosure as defined in the claims. Furthermore,
modifications may be made to adapt a particular situation or
material to the teachings of the present disclosure without
departing from the essential scope thereof. Therefore, it is
intended that the present disclosure not be limited to the
particular examples illustrated by the drawings and described in
the specification as the best mode presently contemplated for
carrying out the teachings of the present disclosure, but that the
scope of the present disclosure will include any embodiments
falling within the foregoing description and the appended claims.
Reference signs mentioned in the claims should not be seen as
limiting the extent of the matter protected by the claims, and
their sole function is to make claims easier to understand.
* * * * *