Information
-
Patent Grant
-
6425169
-
Patent Number
6,425,169
-
Date Filed
Tuesday, March 24, 199826 years ago
-
Date Issued
Tuesday, July 30, 200221 years ago
-
Inventors
-
-
Examiners
- Hughes; S. Thomas
- Compton; Eric
Agents
-
CPC
-
US Classifications
Field of Search
US
- 029 9001
- 451 353
- 451 359
- 015 491
- 015 52
- 015 87
- 015 98
- 403 59
- 403 61
- 403 125
- 403 138
- 403 144
- 403 66
-
International Classifications
- A47L1116
- E01H105
- B24B3900
-
Abstract
A surface working apparatus includes a surface working head arrangement having a frame member and a plurality of surface working members arranged to depend therefrom in the direction of the surface to be worked, each of the plurality of surface working members being mounted resiliently relative to the frame member by one of a plurality of respective resilient mounting arrangements having a resilient member; and a surface working device with a support plate from which a surface working element is to depend from a lower surface thereof, the support plate includes an upper surface which has a central region with a recess provided for the receipt of a drive member for rotating the device, the recess including a formation for receiving a resilient member for engagement by the drive member.
Description
BACKGROUND OF THE INVENTION
The present invention relates to surface working apparatus and in particular, but not exclusively, to surface working apparatus having a surface working head arrangement with a plurality of surface working elements depending therefrom, which elements are particularly adapted for an operation such as burnishing and which elements particularly exhibit relatively limited flexibility/compressibility.
DESCRIPTION OF THE RELATED ART
Various versions of surface working apparatus are known which can be operated for tasks such as burnishing and wherein the surface working elements comprise pad members which exhibit a relative lack of compressibility/flexibility when compared with other surface working elements such as brushes etc.
In order to provide an efficient surface working apparatus, a surface working head arrangement is currently provided with has a plurality of such pads, or other surface working elements, depending therefrom such that a plurality of pads or other elements are operated simultaneously to achieve the surface working action required, be it burnishing, scrubbing, cleaning or polishing etc.
However, such apparatus is commonly required to operate over a variety of surfaces offering different characteristics and, in particular, different degrees of uniformity. For example, while some surfaces to be worked may comprise a relatively level and smooth surface, other surfaces, particularly those prone to excessive wear or potential damage, and/or older surfaces, may exhibit undulations such that a relatively uneven surface is presented for working.
Known surface working apparatus is disadvantageously limited in that the quality of surface working that can be achieved is limited since the plurality of surface working elements cannot adequately compensate for such uneven surfaces.
SUMMARY OF THE INVENTION
The present invention therefore seeks to provide a surface working apparatus having advantages over known such apparatus.
According to one aspect of the present invention there is provided surface working apparatus comprising a surface working head arrangement having a frame member and including a plurality of surface working members arranged to depend therefrom in the direction of the surface to be worked, wherein each of the said plurality of surface working members is mounted resiliently relative to the said frame member by one of a plurality of respective resilient mounting arrangements.
The independent, and resilient mounting of each of the surface working members, e.g. a pad member, advantageously allows for each of the surface working members to move relative to the frame member so as to compensate for undulations or unevenness in the surface being worked. Thus, whilst the frame member may be held at a constant level, determined by the pressure to be applied, over the undulating surface, the respective surface working members can move relative to that level so as to follow independently the undulations of the surface.
Drive means are associated with the surface working apparatus for driving the surface working members and such drive means are advantageously mounted to the frame member and the surface working members then resiliently mounted to the drive means. Most appropriately, a corresponding plurality of respective drive means is also provided on the surface working apparatus.
Preferably, the resilient mounting arrangement includes a compression spring which can be further advantageously arranged to be compressed to substantially half its length when the surface working head arrangement is exhibiting the particular required force on the surface being worked. Thus, the characteristics of the compression spring are advantageously matched to the particular nature of the surface working member associated therewith, be it a pad member, brush member or other appropriate member.
The resilient member is advantageously located between the drive shaft of the drive means and a surface working member drive adaptor means. Further, a drive motor adaptor is drivingly located between the motor drive shaft and the resilient member.
Preferably, the surface working drive adaptor means includes a hollow cylindrical housing member for receiving one end of the motor drive shaft adaptor.
The resilient means is then advantageously located within the cylindrical housing for contact between a lower surface thereof and a lower surface of the motor drive shaft adaptor.
Preferably, the resilient mounting arrangement is arranged to be selectively operative dependent upon the pressure to be exerted through the surface working head arrangement and to the surface to be worked. This is a particularly advantageous feature since, when pressure levels exceed those that might otherwise damage the resilient member of the resilient mounting arrangement, the further biasing of the resilient member is prevented so as to prevent damage thereto during the further increase in pressure to be applied to the surface. Thus, as the pressure is increased above the aforementioned threshold level, pressure is no longer applied by way of the resilient member of the surface working head arrangement.
The selective operation is achieved through movement of the resilient member within the mounting arrangement and into, and out of, a position in which it can be influenced by increases/decreases in pressure.
The resilient means advantageously moves out of its operative position, i.e. a position in which it can be further compressed, once the pressure applied through the surface working head arrangement exceeds a certain, and in particular predetermined, level.
Advantageously, the resilient mounting arrangement includes a housing provided with an engagement formation which is arranged to be engaged so as to prevent further biasing of the resilient member as the pressure to be applied to the surface increases.
The resilient member advantageously comprises a compression spring which can be arranged to be compressed to substantially half its length when the required pressure is to be applied to the surface by way of the surface working head arrangement.
Further, the aforementioned engagement formation can advantageously comprise a shoulder portion arranged adjacent the resilient member and, insofar as the housing includes a bore portion, the engagement formation can advantageously comprise an annular shoulder member which can further be in the form of an annular shoulder surrounding a well, or a cylindrical recess portion.
Advantageously, the housing arrangement is arranged for providing a driving connection to a drive member extending from a motor arrangement for the surface working member and, in particular, the resilient member is arranged to contact the underside of the aforementioned driving member.
Further, the resilient member may be associated with a contact plate for contacting the aforementioned driving member.
Yet further, the undersurface of the driving member which is arranged to contact the resilient member by way of the aforementioned contact plate, or otherwise, can advantageously be provided with a chamferred, partially convex, or part spherical surface which serves to assist with a gimbal-like movement of the housing member relative to the driving member extending from the motor.
With regard to a further advantage, the housing member is provided with a resilient clip means serving to retain the driving member extending from the motor arrangement within the housing.
Advantageously, the driving member has an engagement formation arranged to receive the clip means so as to prevent its removal from the housing. The aforementioned engagement formation of the driving member can advantageously be in the form of a shoulder portion of the driving shaft.
Advantageously, the transverse cross section of the driving shaft comprises a polygon and, in particular, a hexagon. In particular, it may comprise a star shape or an appropriate form of scalloped hexagon.
In any case, the transverse cross-section advantageously exhibits corner regions and a recess can be formed in a side wall portion of the bore that receives the driving member so as to guide and retain operative movement of the clip in the region of the shoulder portion of the driving shaft.
The clip means is advantageously arranged to be deformed so as to allow for entry/exit of the driving member relative to the housing and, in particular, it is the angled side walls defined by the hexagonal cross-section that serve as ramp means for at least a portion of the clip means so that, as the aforesaid portion is moved along the ramp means, the clip means is deformed outwardly relative the centre of the driving member so as to allow for its removal from the housing.
The present invention also advantageously provides for a surface working device such as a pad or brush which can be employed in apparatus as defined above.
Thus, in accordance with another aspect of the present invention there is provided a surface working device comprising a support plate from which a surface working element is to depend from a lower surface thereof, said support plate including an upper surface which has a central region with a recess provided therein for the receipt of a drive member for rotating the device, wherein the recess includes a formation for receiving a resilient member intended for engagement by the drive member.
The formation provided in the recess advantageously serves to engage at least one portion of the resilient member such that another portion of the resilient member can be engaged by the drive member so that relative movement between the drive member and the support plate can be achieved whilst deforming the resilient member.
Advantageously, the said central region comprises an upstanding region with the recess provided therein. If required, the recess can therefore be provided within the upstanding central region so that the depth of the recess is not dependent upon the thickness of the support plate.
In particular, the upstanding region can comprise an upstanding cylindrical member having the recess formed therein and which is coaxial with the support plate.
While the support plate can itself be provided with formations for receiving the portion defining the said central region, the central region defining the recess can advantageously be formed integral with the support plate.
In one particular embodiment, the said recess comprises a substantially blind bore which may advantageously have an end surface exhibiting a generally concave profile.
The generally concave profile can advantageously serve to enhance any gimballing effect that may be required between the drive member and the device.
Preferably, the said formation for receiving the resilient member can itself comprise a further recess which, advantageously, can be formed coaxially with the said recess formed at the central region of the support plate.
The said further recess can advantageously be in the form of a substantially blind bore. In any case, the depth of the recess is chosen so as to determine the maximum deformation of the resilient member.
Advantageously, the resilient member can comprise a compression spring which is arranged to extend coaxially with the said further recess and the recess provided in the said central region of the support plate.
In one particular embodiment, the recess provided in the central region of the support plate has a substantially hexagonal lateral cross-section and is arranged for receiving a substantially hexagonal head of the drive member.
The depth of the recess formed in the central region is advantageously formed to be at least slightly greater than the depth of the head of the drive member. In this manner, the said central region of the support plate can be advantageously provided with a spring retaining clip which requires deformation to allow the drive head into, or out of, the recess formed within the central region of the support plate.
The present invention is particularly advantageous when embodied with a surface working head arrangement exhibiting at least three surface working members which, when viewed from above, can be provided in a triangular formation on the frame of the surface working head arrangement. As mentioned before, such surface working members advantageously comprise pads, which, in particular, are arranged for burnishing of the surface to be worked.
In the aforementioned manner, the frame member of the surface working head arrangement can comprise a laterally extending deck member having a plurality of drive motors extending from the upper surface thereof and a plurality of respective surface working members extending from the lower surface thereof aligned with the motors.
Advantageously, the surface working apparatus Comprises a machine frame supporting a motor-driven surface working head arrangement, means for selectively varying the pressure exerted by said head arrangement on said surface, and means for selectively varying the speed at which said head arrangement is driven by said motor.
Preferably, the surface working head arrangement is adapted for the releasable mounting of a variety of surface working elements. Further, the surface working head arrangement can be arranged for releasable mounting of a plurality of surface working members each having different surface working characteristics.
The means for selectively varying the pressure exerted by the surface working head can be arranged to alter said pressure in response to use of said surface working head means exhibiting different working characteristics.
Further, the means for selectively varying the speed at which said head arrangement is driven by said motor may be arranged such that said speed can be altered in response to use of said surface working head means exhibiting different characteristics.
Advantageously, the apparatus includes actuator arrangement comprising spring means mounted to act as suspension means including means for biasing the surface working head arrangement towards a surface to be worked, tensioning means for tensioning the spring means so as to set the pressure of the surface working head arrangement and wherein the spring means is selectively adjustable by the tensioning means over a continuous range to provide a required bias towards the surface.
The tensioning means may include means for controlling the tension in the spring means so as to vary the bias of the surface working head arrangement. Also, the actuator arrangement can be arranged to compress the spring means.
The apparatus may further include biasing means acting between the frame and the surface working head arrangement to apply to the surface working head arrangement a selectable bias towards the surface to be worked and mounted to act as suspension means between the frame and the surface working head arrangement, means for monitoring and/or measuring the applied working pressure, means for displaying an indication of the measured working pressure, means for operator entry of a desired working pressure for the surface working head arrangement and, comparator means for comparing the operator input pressure to the measured pressure and for generating a control signal in response to the difference between the desired pressure and the measured pressure and means for applying the control signal to the pressure applying means.
The means for selectively varying the pressure applied to the surface by said surface working head arrangement can comprise biasing means acting between the frame and said surface working head arrangement and comprising an actuator having a first member, and a second member extendible therefrom and which actuator is further preferably operable manually, hydraulically or electrically.
The biasing means advantageously comprises a spring means which may further include at least one spring device acting between a portion of the actuator and the surface working head arrangement. The spring device can comprise a sleeve secured to said portion of said actuator means, a rod having an inner end slidable within the sleeve, the rod projecting from the sleeve to the surface working head arrangement, and a spring located within the sleeve engaging the inner end of the rod.
Further, the apparatus can include an actuator arrangement for raising and lowering the surface working head arrangement and mounted between the frame and the surface working head arrangement, and means operatively connected to the surface working head arrangement and arranged to at least partially counteract the force to be exerted via the surface working head arrangement on the surface, and so as to control the pressure exerted by the surface working head arrangement on the surface to a range which includes zero pressure to a pressure corresponding to the weight of the surface working head arrangement.
In particular, the means for counteracting the force exerted on the surface working head arrangement by the actuator can comprise counterbalancing means.
The means for counteracting can comprise resilient means operatively connected to the surface working head arrangement.
Advantageously, the resilience of the resilient means is selectively variable.
Preferably, the resilient means comprises at least two relatively moveable members which are arranged to be relatively movable in a resilient manner. The resilient means advantageously comprises a cylinder and piston arrangement.
The resilient means can then comprise a gas strut arrangement.
Alternatively, the resilient means can comprise spring means.
As a further alternative, the means for selectively varying the pressure exerted by the surface working head arrangement comprises an elongate balance beam pivotally connected to the frame and connected at one end to the actuator for movement therewith, and at the other end having a counter balance mounted thereon.
The means for selectively varying the speed at which the head arrangement is driven can comprise a selective plurality of gear arrangements having gear ratios determined on the basis of the working operations required.
The gearing arrangement preferably comprises respective pairs of gears in constant mesh and means for selecting one of said pairs for delivering the upward drive from said gearbox.
The means for selecting said one of said pairs advantageously comprises clutch means in the form of dog-clutch means.
The apparatus can further include control means comprising a solenoid actuator arranged to be retained in its two or more possible operative positions by solenoid locking means.
Preferably, means for controlling switching in the gearbox and which is associated with the means for selecting the pressure applied by way of the surface working head arrangement can be provided so that the switching of the gearbox is achieved in response to the selection of particular pressure values either above or below one or more threshold values or the selection of specific values.
Preferably, the apparatus has a control arrangement arranged such that the selection of any particular pressure value or range is responsive to switching of the gearbox. Further, the gearing arrangement advantageously comprises a first gear pair with a 1:1 ratio and a second gear pair with a 5:1 ratio.
Control means can be provided to inhibit the change in the gearing mechanism while the motor is driving the surface head arrangement. In particular, the control means is arranged to limit the pressure that can be applied by way of the surface working head arrangement once the high speed gear ratio is selected.
Advantageously, the apparatus comprises a combined floor scrubber/burnisher machine.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings in which:
FIG. 1
shows a cross-sectional elevational view of part of a surface working head arrangement and associated actuator embodying the present invention;
FIG. 2
is a perspective view of a surface working head arrangement embodying the present invention and arranged for operation with the actuator of
FIG. 1
;
FIG. 3
is a side elevational view of the deck arrangement of the surface working head arrangement of
FIG. 2
;
FIG. 4
is a schematic exploded view of one of the surface working members of the surface working head arrangement of
FIGS. 2 and 3
;
FIGS. 5A-5C
are schematic views of the surface working member of
FIG. 4
at different stages in the operation of the apparatus embodying the present invention;
FIGS. 6A-6E
illustrate a mounting formation of a surface working member according to, and also a spring latch member associated with, an embodiment of the present invention;
FIG. 7
is a side view of a brush/pad pressure assembly associated with the apparatus of the present invention;
FIG. 8
is a side view of another version of a brush/pad pressure assembly associated with the embodiment of the present invention;
FIG. 9
is a side view of yet another version of a brush/pad pressure assembly associated with an embodiment of the present invention;
FIGS. 10A-10H
comprise a circuit diagram illustrating control means that can be associated with apparatus embodying the present invention;
FIG. 11
is a cross-sectional view through a selectively operable gearing arrangement for use in selecting the speed in which the surface working means of the present invention is driven.
FIG. 12
is a plan view of the central region of a surface working device embodying one aspect of the present invention and as shown in longitudinal cross-section in
FIG. 13
;
FIG. 14
is a plan view of the central region of
FIG. 12
but illustrating further mounting and retention features of this embodiment of one aspect of the invention;
FIG. 15
is a side elevational view of a drive member for rotatably driving the device of
FIGS. 12-15
;
FIG. 16
is a plan view of the drive member of
FIG. 15
; and
FIG. 17
is an exploded respective view of the complete surface working device embodying one aspect of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In
FIG. 1
, the brush/pad assembly comprises two spring tubes
1
, containing springs
2
. The right hand tube
1
in
FIG. 1
is shown in cut-away to illustrate spring
2
. Each spring is fixed at one end to the upper end of the tubes at
3
and at the other end to a spring rod
4
which slides through an aperture
5
into the respective spring tube
1
. The spring rods
4
are connected together by a bolt
6
and are fixed via assembly
7
to the brush/pad support deck
8
to which brush head or pads etc can be connected. The brush or pads are releasably secured to the assembly so as to allow for ready replacement by other heads as required.
The tubes
1
are prevented from rotating or skewing by a steadying plate
9
. An actuator
10
is secured to a bulkhead of a cleaning machine. Actuator
10
drives actuator rod
12
which is shown in substantially closed up position in the Figure. The actuator rod
12
is fixed by a pin
13
to actuator plate
14
which is clamped to both spring tubes
1
by clamping bolts
15
. Thus as the actuator drives the actuator rod
12
downwards, the spring tubes
1
move downwards and the springs
2
are compressed causing a higher pressure to be exerted on the brush head assembly whilst still providing suspension to accommodate uneven floors and brush wear. Typically, the effective spring lengths, in an uncompressed state, are around 15 inches and this is particularly suitable for a 26/32 inch brush pressure system. Such an arrangement can provide a range of 0 to 450 lb pressure in a loaded pedestrian cleaning machine fitted with apparatus according to the invention, compared to the maximum 200 lb pressure available using known apparatus. Of course other forms of biasing means could be used. A torsion spring has the advantage of taking up less vertical space in a cleaning machine. Also, a torsion spring generally has a low spring rate which is particularly suitable for this purpose. Gas struts or hydraulic or pneumatic systems could also be used.
The pressure can be further adjusted by changing the springs for different length ones or different strengths since the clamping position of the spring tubes can be altered. However these changes require a service engineer.
The system is particularly adjustable since the actuator can be stopped anywhere in its stroke.
Usually support deck
8
will have attached at least two circular or elliptical brushes or pads rotating in a plane generally parallel to the floor (or surface to be cleaned or swept or scrubbed). However, up to four brushes or pads are in use in some cleaning machines and the apparatus of the invention could be used to control all such four brushes together or alternatively individually (in which case separate actuators would be used for each). Of course a cylindrical brush head could equally easily be controlled mounted on the brush support deck
8
or alternatively controlled at each end of its shaft by respective separate assemblies according to FIG.
1
.
A strain gauge beam
20
which may be used to measure the brush/pad pressure is located under the spring tube clamp plate
18
.
FIG. 2
is a perspective view of a surface working head arrangement for use with an actuator arrangement such as that illustrated in FIG.
1
and which includes the spring tubes
1
and actuator
10
illustrated further in FIG.
1
.
The surface working head arrangement also includes the brush/pad deck
8
illustrated in FIG.
1
and has three electric drive motors
21
a
,
21
b
,
21
c
mounted on the other surface of the deck
8
. Three corresponding brush/pad heads
22
a
,
22
b
,
22
c
extend from beneath the deck and are drivingly connected, by way of respective drive shafts, to the respective motors
21
a
,
21
b
,
21
c.
As will be appreciated from the triangular formation of the three motors
21
a
,
21
b
,
21
c
and associated brush/pad heads
22
a
,
22
b
,
22
c
a predetermined overlap is achieved between brush/pad heads
22
a
and
22
b
and between brush/pad head
22
b
and
22
c
so that the brush/pad head arrangement of
FIG. 2
can serve to clean, sweep, polish, burnish, or otherwise work, a surface to the full width defined by the separation of the outer circumferential edges of the brush/pads
22
a
,
22
c.
The width, when viewed in a surface working direction is illustrated further by way of
FIG. 3
which is a front elevational view of merely the deck
8
, motors
21
a
,
21
b
,
21
c
and brush/pad heads
22
a
,
22
b
,
22
c
when in use for working, for example burnishing, a surface
23
.
Indeed,
FIG. 3
illustrates a particularly important aspect of the present invention in that it will be appreciated that, due to undulations in the surface
23
being burnished, the surface presents a somewhat uneven surface to the burnishing apparatus such that the surface
23
does not extend in a uniform parallel manner in relation to the lateral extension of the deck
8
.
Thus, the distance between the undersurface of the deck
8
and the surface being worked
23
is, due to undulations and unevenness, less in the right hand region of
FIG. 3
than in the left hand region.
With prior art apparatus, this would lead to the region of the surface
23
beneath the motors
21
a
and
21
b
not being satisfactorily burnished, or otherwise worked, so that the whole surface
23
might not be satisfactorily worked or, at best, might require a greater number of passes using the apparatus which then offsets the advantages generally found from using a multi-head burnishing or surface working apparatus.
As mentioned,
FIG. 3
illustrates a particularly important aspect of the present invention which is discussed in further detail below. However, from
FIG. 3
, it will be appreciated that each of the brush/pad heads
22
a
,
22
b
,
22
c
mounted beneath the deck
8
is mounted in a dependent manner moveable relative to the deck
8
so that the depth to which the pads/heads
22
a
,
22
b
,
22
c
extend beneath the deck
8
can vary independently and follow undulations in the surface being worked such as that illustrated in the surface
23
of FIG.
3
.
Thus, even the undulations in surface
23
can be satisfactorily worked by way of the brush/pad heads
22
a
,
22
b
,
22
c
such that the advantages achieved by using a multi-head arrangement can be maintained even when working an undulating or otherwise uneven surface.
FIG. 4
shows in greater detail one of the independent mounting arrangements employed within the embodiment of the present invention illustrated herein and so only one
21
a
,
22
a
of the motors and brush/pad heads is illustrated in FIG.
4
.
A motor drive shaft
24
extends downwardly from the motor
21
a
and through an appropriate aperture formed in deck
8
and is received in a female engagement portion of a drive shaft adaptor
25
. The motor drive shaft
24
is advantageously keyed into the drive shaft adaptor
25
.
The drive shaft adaptor
25
includes an upper cylindrical portion
26
and a head portion
27
having a hexagonal transverse cross section. The hexagonal head portion
27
has an undersurface which is rounded in some manner so as to provide a chamferred or otherwise formed as a convex, or part spherical, surface
28
and the drive shaft adaptor
25
is further provided with a bore
29
extending along the longitudinal axis thereof into which the motor drive shaft
24
is keyed.
The shaping of this lower surface serves to assist in permitting the movement of the brush/pad heads in a slightly pivoted manner relative to the deck
8
to further follow changes in the inclination of regions of the surface being worked.
The drive shaft adaptor
25
is arranged to be received within a drive plate adaptor
30
for driving engagement therewith. The drive plate adaptor
30
includes an upstanding collar portion
31
having a cylindrical outer surface and presenting an inner bore with a hexagonal transverse cross section arranged to correspond to the hexagonal cross section of the head portion
27
of the drive shaft adaptor
25
. The lower region of the bore formed by the collar portion
31
is provided with a cylindrical well
32
which likewise defines shoulder portions
33
in the regions within the bore of the collar portion
31
.
A compression spring is inserted in the well
32
so as to be received, and retained, therein and the end of the compression spring
34
remote from the well
32
is provided with a hexagonal contact plate
35
, such as a star shaped or scalloped hexagonal shaped contact plate, which is arranged to contact the under surface
28
of the drive shaft adaptor
25
as it is inserted into the collar portion
31
of the drive plate adaptor
30
.
By virtue of the respective hexagonal or star shaped cross sections for the inner surface of the collar portion
31
and the head portion
27
of the drive shaft adaptor
25
, the drive shaft adaptor
25
is effectively keyed into the drive plate adaptor
30
so as to drivingly rotate the drive plate adaptor
30
. The drive plate adaptor
30
is connected to an annular drive plate
36
which, in turn, has an annular burnishing pad
37
mounted thereon. Thus, rotation of the motor drive shaft
24
effects rotation of the burnishing pad
37
.
FIGS. 5A
,
5
B and
5
C provide a further illustration of the resilient mounting arrangement for each of the brush/pads of the present invention. In
FIG. 5A
, the mounting arrangement of
FIG. 4
is shown in greater detail but without reference to the motor
21
a
and the brush/pad deck
8
and with the drive shaft adaptor
25
inserted into the collar portion
31
such that the rounded undersurface
28
of the head portion
27
contacts the contact plate
35
associated with the compression spring
34
.
This drawing would typically represent the positions of the various elements of the mounting arrangement if known pressure were to be applied through the actuator
10
of the brush head arrangement.
In
FIG. 5B
, the features of
FIG. 5A
are shown but this time with the compression spring
34
being partially compressed under light pressure. The compression spring
34
is advantageously provided such that it is arranged to compressed to substantially half its length when the pressure appropriate to the particular surface working action is to be applied and, as will be appreciated, compression of the compression spring
34
allows for the annular pad
37
to move downwardly relative to the deck
8
should any undulations in the surface being worked be encountered.
FIG. 5C
illustrates a further aspect of the present invention in that, when the apparatus is controlled so as to exert a heavy scrub pressure, the compression of the compression spring
34
is limited in view of its location within the well
32
of the drive plate adaptor
30
. As will be appreciated from
FIG. 5C
under such heavy pressures, the drive shaft adaptor
25
is moved to the maximum extent into the bore of the collar portion
31
so that the hexagonal contact plate
35
abuts against the shoulder portions
33
of the inner surface of the collar portion
31
adjacent the well
32
. As the pressure increases further, it will be appreciated the pressure exerted by way of the drive shaft adaptor
25
is exerted directly on to the drive plate adaptor
30
, by way of the hexagonal contact plate
35
, and no further compression of the compression spring
34
occurs. It is therefore important that the depth of the well
32
correspond to a length for the compression spring
34
that can be readily achieved without the compression spring
34
being damaged.
FIG. 6A
which represents a further plan view of the mounting arrangement for a surface working head of the present invention and illustrates a plan view of the drive shaft adaptor
25
located within the collar portion
31
of the drive plate adaptor
30
.
As will be seen, a rectilinear latch spring
38
(see
FIG. 6C
) is illustrated and which is formed so as to extend over two of the corners formed on the star shaped, or scalloped hexagonal shaped, upper surface of the head portion
27
of the drive shaft adaptor
25
.
In this manner, the drive shaft adaptor
25
is retained within the collar portion
31
of the drive plate adaptor
30
.
However, the latch spring member
38
comprises a resilient member which can be deformed so as to allow for entry into, or exit from, the bore formed with the collar portion
31
.
The rectilinear latch spring
38
is provided with a detent portion
39
by means of which it can be pulled in the direction of arrow A in FIG.
6
A. Pulling the latch spring arrangement
38
in the direction of arrow A so as to move lateral leg portions which extend down the side walls of the head portion
27
, outwardly along a line of travel defined by the outer walls of the star shaped cross section of the head portion
27
so that the laterally extending portion of the latch spring
38
is moved outwardly from its position above the upper surface of the head portion
27
. This release position for the latch spring
38
once having been moved in the direction of arrow A is illustrated by the chain dotted representation of the latch spring
38
in FIG.
6
A.
In
FIG. 6B
, there is illustrated a cross section of one particular version of the drive plate adaptor
30
according to the embodiment of the present invention and which includes a pair of recesses
40
provided in operations of the outer surfaces of the collar portion
31
of the drive plate adaptor
30
.
FIGS. 6C
,
6
D and
6
E are plan side and end views of the latch spring
38
discussed above.
It will be appreciated that the latch spring
38
is received within the recesses
40
when in the retaining position shown in
FIG. 6A
so as to extend over the corner portions of the upper surface of the head portion
27
. However, the latch spring
38
can readily move laterally within the recesses
40
so as to allow for the aforementioned opening of the latch spring
38
to allow for the release of the drive shaft adaptor
25
from the collar portion
31
of the drive plate adaptor
30
.
The latch spring arrangement
38
is a particularly advantageous feature of the present invention which allows for the ready “snap-fit” of the head portion
27
of the drive shaft adaptor
25
within the collar portion
31
of the drive plate adaptor
30
and the ready removal therefrom when the surface working member, such as a pad or brush is to be replaced.
Turning now to
FIGS. 7
,
8
and
9
there is shown a balance beam
132
mounted by pivot bearing
133
to one end of a pivot support
134
, the other end of which is connected to the frame. The beam
132
is also connected to actuator arm
1
and on the other side of the pivot bearing
133
to a counterbalance means in the form of a gas strut
135
,
137
(see
FIGS. 8 and 9
) to counterbalance the weight of the brush head. The opposite end of beam
132
is linked to the brush head by a turnbuckle linkage
36
, which is used to adjust the counterbalance for brushes of different length, for example to prevent jamming of the brushes against the floor.
A potentiometer
333
for measuring brush wear is connected between the balance beam
132
and the pivot support
134
.
Further support for the brush head is provided by a parallelogram linkage
138
between the brush head and the side of the main frame to keep the brush deck positioned.
A drive wheel
139
for the machine is shown: usually one such wheel is positioned at each corner of the chassis or frame.
The path of movement of the counterweight is shown by arrow A, as the brushes are raised by the lower line and as they are lowered by the upper line. As the brushes are lowered to the floor by the actuator
10
the balance beam
132
rotates about pivot bearing
133
serving to compress the gas strut arrangement
135
,
137
. The deck
8
is lowered to the floor by the extension of the actuator
1
. However as the deck
8
approaches the floor, the pressure to be exerted by the deck
8
on the floor is advantageously counterbalanced by the gas strut means
135
,
137
. This counterbalancing action is achieved by the compression of the gas strut arrangement
135
,
137
which, having a sealed volume within the chamber
135
, limits the degree to which the piston member
137
is slidable within the chamber
135
and, advantageously in a resilient manner. Thus, the relative movement between the piston member
137
and the chamber
135
advantageously allows for the exertion of an accurately determinable low pressure at the brush head
8
since the limiting, and thus counterbalancing, effect of the gas strut arrangement
135
,
137
serves to effectively reduce the pressure applied by way of the actuator
1
, and through the deck
8
, to the floor.
When the force exerted by the actuator
1
on the deck
8
is removed, i.e. the actuator
1
is retracted so as to raise the deck
8
, the compressed pressure within the chamber
135
is relieved and the gas strut arrangement
135
,
137
extends and the volume of fluid introduced into the chamber
135
is chosen such that the extended gas strut arrangement
135
,
137
can readily support the deck
8
in such a raised position.
It will be appreciated that, by acting as a counterbalancing force, the gas strut arrangement
135
,
137
serves to offer support for the weight of the brush head
8
and allows the net force exerted by way of the actuator
1
through the deck
8
onto the floor to be accurately controlled particularly in the range of zero pressure to pressure corresponding to the weight of the deck
8
.
FIG. 8
is a side view of another embodiment of the present invention in which the features common to
FIG. 7
are provided with the same reference numerals.
The counterbalance arrangement illustrated in
FIG. 8
operates in a similar manner to that illustrated with reference to
FIG. 7
in that, as the deck
8
is lowered towards the floor by means of the actuator
1
, the gas strut arrangement
135
a
,
137
a
is compressed.
As will be appreciated from
FIG. 8
, the device includes a shorter parallelogram arrangement
138
a
than found in
FIG. 7
, and the gas strut arrangement
135
a
,
137
a
is operatively connected between a frame portion of the sweeping/cleaning machine and the deck
8
by means of its connection to the lower strut of the parallelogram arrangement
138
a
. As will be appreciated, as the deck
8
is moved towards contact with the floor surface to be swept or cleaned the parallelogram arrangement
138
a
pivots in a clockwise manner serving to move the piston member
137
a
into the chamber
135
a
of the gas strut arrangement and which relative movement is gradually resisted by the pressure developed within the chamber
135
a
. The counterbalancing force offered by the gas strut arrangement
135
a
,
137
a
shown in
FIG. 8
serves to provide a net force at the deck
8
which can readily be controlled particularly in the range zero pressure to a pressure corresponding to the weight of the deck
8
.
Turning now to
FIG. 9
, yet another embodiment of the present invention is illustrated and in which the features common to
FIGS. 7 and 8
have been given similar reference numerals.
The main difference between the embodiment of FIG.
9
and the embodiments of
FIGS. 7 and 8
is that the required net force exerted by the brushes or pads on the surface is achieved when the gas strut arrangement
135
b
,
137
b
is extended rather than compressed. Again, it is the pressure within the chamber
135
b
that limits the extent to which the piston member
137
b
can be extended therefrom and this serves to counterbalance the force exerted by way of the actuator
1
. The gas strut arrangement
135
b
,
137
b
of the embodiment of
FIG. 9
is operatively connected between an extension bracket
140
of the frame
130
of the cleaning machine and a connection lug
141
of the deck
8
. As will be appreciated from
FIG. 9
, as the actuator is operated so as to lower the brush head arrangement towards the ground to be swept/cleaned, the gas strut arrangement
135
b
,
137
b
is extended and effectively becomes tensioned in view of the pressure developed within the chamber
135
b
. In reverse when the brush head arrangement is raised from the floor, the pressure developed within the chamber
135
b
by the previous relative movement between the chamber
135
b
and the piston member
137
b
serves to assist with supporting the weight of the brush head arrangement clear of the floor.
As with each of the embodiments described herein, the gas strut arrangement can advantageously be provided in a manner such that the pressure within the chamber thereof can be selectively varied to any particular value when the brush pressure arrangement is at rest, i.e. when the brush head arrangement is raised from the floor.
The circuit of
FIGS. 10A-10H
can be used as the control system for the system and provides for an advantageous arrangement for achieving accurate control of the pressure and speeds required of the present invention. It comprises standard integrated circuits including a programmed micro controller or micro-processor U
3
, power supply IC's U
1
, U
4
and U
6
, non-volatile memory store U
2
, and analogue to digital converter U
5
.
A measured pressure signal from a pressure bridge or strain gauge mounted in the cleaning head is input to the microprocessor U
3
via instrumentation amplifier U
7
and analogue to digital converter (ADC) U
5
.
The state of external switch inputs on the cleaning machine are sampled via buffer JP
2
.
The microprocessor U
3
makes appropriate calculations based on the sampled values and the set system variables and outputs control signals via mosfets Q
5
to Q
8
, relays RL
1
, RL
2
, RL
3
, and RL
4
and buffer JP
1
to contact relays to operate the actuator on the cleaning machine itself For example, when relay RL
4
is tripped 365 volts are applied to the cleaning head lowering actuator, when relay RL
3
is tripped 36 volts are applied to raise the cleaning head, and when relay RL
1
is tripped the drive control or traction of the cleaning machine is inhibited. When relay RL
2
is activated, the brush/pad motor solenoid is switched on. This is programmed to occur only when the actual brush pressure and the desired brush pressure are balanced and also only when the machine is in motion to prevent the brushes marking the floors whilst stationary.
The SENSE input on buffer JP
1
senses whether or not the cleaning machine is moving. If it is, then the circuit inhibits pressure changes to avoid damaging the brushes.
The SPEED input on buffer JP
1
senses whether the brushes have been selected for high or low speed. This information is passed to processor U
3
which limits the brush pressure at high speed to a pre-determined range to protect the brush motors.
Buffers JP
2
supplies signals to the machine control panel to display the actual measured pressure indication and the set value indication respectively on LED displays.
Further modifications can be included in this circuit, for example a battery monitor could advantageously be incorporated to record the total usage time and monitor the charge state of the battery. Under certain predetermined conditions, as programmed into the system parameter memory circuit U
2
, the cleaning brushes would be automatically raised. Such conditions would typically be long battery usage and/or low battery charge. The operator would then necessarily have to take the machine back to the depot to recharge or replace the battery thus preserving the warranty on the battery.
The control circuit of the invention is very finely tunable and achieves extremely accurate pressure settings for the brush head.
The micro-controller U
3
is preferably programmed to always effect pressure changes in a direction such that the brushes are moved downwardly and this aids the accuracy of the settings. For example, if a change in pressure from 100 lbs to 40 lbs is required by an operator, the controller will cause a jump to a value around 20 lbs and then slowly increase the pressure up to the required value of around 40 lbs. This arrangement overcomes stiction in the machine. It is particularly advantageous if phase advance calculations are also used by the micro-controller such that the micro controller calculates the speed at which the pressure changes are occurring and makes appropriate adjustments.
The circuit also preferably monitors the state of the external brush head raise/lower switch and the micro-processor U
3
can be programmed to take the state of this switch into account in making decisions on whether to effect certain operations.
FIG. 11
shows a cross-section through a working-head driving arrangement
140
according to one embodiment of the present invention and which comprises a motor
141
in association with a gearbox
142
.
A drive shaft
143
within the motor provides for the rotational input gearbox
142
, and an output shaft
144
extending from the gearbox
142
provides for a driving output of the arrangement to the rotatable cleaning/burnishing head of the apparatus.
The motor comprises a housing
145
which extends in a direction parallel to the motor shaft
143
and a motor closure plate
146
is provided at the end of the motor housing
145
adjacent the gearbox
142
. Indeed, the gearbox is mounted by way of bolt means to the motor closure plate
146
and so that the output shaft
144
of the gearbox
142
extends parallel to the longitudinal axis of the motor shaft
143
.
The gearbox
142
includes a housing which extends from the motor closure plate
146
and which is closed, at its end remote from the motor closure
146
, by a gearbox closure plate
147
through which the output shaft
144
extends.
The input shaft
143
engages with a stub shaft
148
which extends into the gearbox
142
and which is rotatably secured, at its end remote from its engagement with the input shaft
143
, in a locating recess
149
provided in the inner surface of the gearbox closure plate
147
. The locating recess
149
provides for rotatable mounting of the stub shaft
148
within the gearbox.
The stub shaft
148
is provided with two gears along its axial length. A first gear
150
is provided at the end of the stub shaft
148
adjacent to the recess
149
and this first gear
150
has a diameter slightly less than the stub shaft
148
. A second gear
151
located on the stub shaft
148
and adjacent to the motor closure plate
146
has a diameter greater than the stub shaft
148
.
As will be explained later, the first
150
and second
151
gears provided on the stub shaft
148
are arranged to provide predetermined gear ratio within the gear arrangement of the gearbox
142
.
The output shaft
144
is rotatably mounted within the gearbox and, as will be appreciated, extends between respective bearing sets located adjacent to the motor closure plate
146
and the gearbox closure plate
147
.
As with the stub shaft
148
, the output shaft
144
includes two gears spaced along the axial direction of the output shaft
144
such that one of the gears
152
is arranged to mesh with the first gear
150
on the stub shaft
148
and the other of the gears
153
is arranged to mesh with the second gear
151
provided on the stub shaft
148
.
The gear
153
provided on the output shaft
144
is arranged to have a diameter which is the same as that of the second gear
151
on the stub shaft
148
such that the gear ratio between the gears
151
and
153
1:1.
The gear
152
provided on the upward shaft
144
has a larger diameter than the gear
150
provided on the stub shaft
148
, and indeed the gears
151
,
153
.
The gear
152
is chosen such that the gear ratio between the gears
150
and
151
is 5:1.
The aforementioned gear ratios provide for the speed reduction required when switching between a floor scrubbing and floor burnishing operation and so the gearbox of
FIG. 11
provides for an effective two-speed gearbox. As will be appreciated, when the gear pair
151
,
153
provide for rotation of the output shaft
144
, the output shaft rotates at a speed consistent with the speed of the motor, for example 1,000 rpm. However, when the gearbox is switched so that the gear pair
150
,
152
drive the output shaft
144
, the gear ratio 5:1 of this gear pair determines that the speed of the output shaft, and thus the drive to the surface-working head member, is reduced to 200 rpm.
The aforementioned respective speeds are those preferred for scrubbing and burnishing operations and so, along with an appropriate control of the pressure at which the surface-working head member is applied to the surface, scrubbing and burnishing operations can be provided by the apparatus.
As will further be appreciated from
FIG. 11
the gear pairs
151
,
153
and
150
,
152
are mounted in constant mesh and the gears
152
,
153
on the output shaft are arranged to be free running during operation of the motor and to selectively control the drive of the output shaft
144
by means of a dog-clutch
154
.
The dog-clutch
154
is driven by means of an actuator
155
in a reciprocal manner in the direction of arrows A so as to either engage with a face of the gear
152
or a face of the gear
153
. The dog-clutch
154
is provided with opposite facing surfaces including gearing recesses
156
which are arranged to receive gear stubs
157
formed on the aforementioned faces of the gears
152
,
153
.
In its position as illustrated in
FIG. 8
, the dog-clutch
154
is moving into engagement with the gear stubs of the gear
152
so as to provide for a rotational drive to the surface-working head member at a speed of 200 rpm.
The actuator
155
is driven by way of a gear-change actuator assembly which can advantageously be solenoid driven and which can further include solenoid locking means so as to advantageously prevent movement of the dog-clutch once a particular speed rotation of the output shaft
144
has been selected.
As mentioned previously, the gear-change actuator assembly
158
can be advantageously associated with control means whereby the selection of a particular pressure to be applied by way of the surface-working head arrangement serves to actuate the gear-change assembly
158
to select the particular gear ratio, or alternatively, a selection of a particular gear ratio serves to effect, or limit, the pressure applied by way of the selective pressure exertion means in response to the gear ratio selected.
FIGS. 12-17
illustrate the features of one particular embodiment of another aspect of the present invention and which relates to the actual surface working device to be releasably mounted upon a drive member depending downwardly from a surface working machine such as that described hereinbefore.
Indeed, the aspect of the invention illustrated by way of the embodiment of
FIGS. 12-17
relates to one particularly advantageous version of the drive plate mounting arrangement illustrated for example in
FIG. 4
of the present application.
As shown in
FIG. 12
the surface working device for releasible attachment
200
includes a substantially cylindrical upstanding central portion
204
integral with an outwardly extending annular support plate
202
(only shown in FIG.
13
).
The central portion
204
is provided with a blind bore
206
having a hexagonal lateral cross section as clearly shown in FIG.
12
and which has a lower surface
208
formed with a concave profile.
The attachment
200
has a lower surface
210
to which a surface working element such as a pad or brush can be releasibly or fixedly secured.
As is clear from
FIG. 13
, the concave lower surface
208
of the blind bore
206
formed in the upstanding central portion
204
of the attachment is itself provided with a cylindrical blind bore
212
which, as is clear from
FIGS. 12 and 13
, is coaxial with both the main blind bore
206
and the upstanding cylindrical central region
204
.
The smaller blind bore
212
formed in the concave surface
208
comprises an engagement formation as will be described later for receiving a resilient member allowing for resilient movement between the attachment
200
and a drive member received in the recess
206
thereof
Turning now to
FIG. 14
, there is illustrated a plan view of the central region of the surface working attachment which has been assembled ready for releasible attachment on to a drive member of a surface working machine.
The main difference between arrangement as shown in
FIGS. 12 and 14
is that in
FIG. 14
an upper retaining plate
213
having a hexagonal central opening has been secured to the upper face of the central region
200
by screws A and a spring retaining clip
214
has been sandwiched therebetween for lateral movement in the direction of arrows B in FIG.
14
.
As can be appreciated from
FIG. 14
, the retaining spring clip
214
is similar in form to the spring clip
38
illustrated in FIG.
6
A and has leg portions which include regions
214
A,
214
B which extend into opposite regions of the hexagonal blind bore
206
.
The portions
214
A,
214
B of the spring retaining clip
214
can however be deformed radially outwardly of the upstanding central portion
204
in a resilient manner so as to allow for entry of a drive member having a drive head with a hexagonal cross section similar in dimensions to the hexagonal cross section of the blind bore
206
. Once the hexagonal drive head of the drive member has passed into the blind bore however, the portions
214
A,
214
B of the spring clip
214
return to the position shown in
FIG. 14
so as to prevent movement of the hexagonal drive head of the drive member until required. When such removal is required, the regions
214
A,
214
B of the spring retaining clip
214
can be deformed radially outwardly of the upstanding portion
204
so as to allow for removal of the hexagonal head of the drive member.
One such drive member
216
is illustrated by way of
FIGS. 15 and 16
and comprises a central cylindrical shaft
218
having a hexagonal drive head
220
formed at the lower end thereof.
The undersurface of the drive head
222
is provided with a gently convex profile. Such a gently convex surface
222
can advantageously cooperate with the gently concave surface
208
of the blind bore
206
as shown in
FIG. 13
so as to allow for a slight gimballing effect between the drive shaft
216
and the attachment
200
.
Turning finally to
FIG. 17
, there is shown an exploded perspective view of various features of
FIGS. 12-16
when arranged for assembly.
As can be appreciated, the mounting plate
213
is arranged to be secured by screws
232
to the upper surface of the upstanding central cylindrical portion
204
so as to sandwich the spring retaining clip
214
therebetween.
The recess
206
is then ready to receive the head
220
of the driving member
216
and which is retained therein by means of the spring retaining clip
214
.
However, prior to insertion of the driver member
216
into the blind bore
206
, a compression spring
226
is located coaxially within the blind bore
206
and so as to have its lower region received in the smaller blind bore
212
illustrated in FIG.
13
.
An engagement plate
224
is located above the spring
226
once received in the smaller blind bore
212
and the plate
224
is itself then arranged to be sandwiched between the upper region of the spring
226
and the undersurface of the hexagonal head of the driving member
216
.
The depth of the smaller blind bore
212
is advantageously chosen so as to determine the maximum compression that the spring
226
will have to suffer and is a particularly advantageous example of a spring-engagement formation to be provided within the blind bore of the central region of the support plate for the surface working element.
FIG. 17
further illustrates the nature of such a surface working element such as a brush
228
which is arranged to depend downwardly from the support plate
202
and which can be secured to the small plate by means of mounting screws
230
.
The further aspect of the invention as illustrated in
FIGS. 12-17
is not restricted to the particular details shown since it should be appreciated that any appropriate recess can be provided for receiving the driving member and which itself can be provided with any appropriate formation for receiving part of a resilient member which of course may be in any appropriate form.
For example, in
FIG. 17
the mounting plate
213
can be arranged for rotation between positions allowing for the securing or release of the driving member
216
. Also, while the dimensions of the illustrated elements can be determined as required, the height of the upstanding central portion
204
is preferably greater than {fraction (1/2+L )} inch (1.27 cm).
However, it will be appreciated that, in common with the embodiment of
FIGS. 12-17
, the further aspect of the present invention is advantageous in providing for a readily reasonably securable surface working device that can nevertheless exhibit appropriate resilient mounting so as to independently follow any undulations in the surface being worked independently of the movement of any other surface working devices that might be attached to one of the same surface working machine.
It should be appreciated that the surface working head arrangement of the present invention can be embodied in any appropriate surface working apparatus other than the combined burnishing/scrubbing apparatus illustrated herein.
Claims
- 1. Surface working apparatus with a surface working head arrangement comprising:a frame member; a plurality of surface working members arranged to depend from said frame member in a direction of the surface to be worked, each of said plurality of surface working members being mounted resiliently relative to said frame member by one of a plurality of respective resilient mounting arrangements having a resilient member; an actuator arranged to act downwardly on the frame member, said actuator comprising a spring suspension means for biasing the frame member, the spring suspension means commonly biasing the plurality of surface working members towards the surface to be worked through the biasing of the frame member, a tensioning means for tensioning the spring suspension means so as to commonly set a pressure of the plurality of surface working members, the spring means being selectively adjustable by the tensioning means over a continuous range to provide a required common bias towards the surface through the frame member; drive means mounted to said frame member with said surface working members being resiliently mounted to said drive means; each of said drive means comprising a drive shaft, said resilient member being located between said drive shaft of one of said drive means and a surface working member drive adaptor means such that each said resilient member is operatively coupled in series with said spring suspension means so that the force to be exerted on the surface by operation of the actuator can be delivered via both the spring suspension means and each of said resilient members providing self-leveling of the corresponding working member; said surface working means comprising a drive motor shaft adaptor, said drive motor shaft adaptor being drivingly located between said drive shaft and said resilient member, said surface working drive adaptor comprising a hollow cylindrical housing recess portion for receiving one end of said drive motor shaft adaptor, wherein said resilient member is located within a cylindrical housing recess portion for contact between a lower surface thereof and an undersurface of said drive motor shaft adaptor, said cylindrical housing recess portion within which the resilient member is located comprising a further recess formed coaxially with said cylindrical housing recess portion, and the further recess serving to determine the maximum deformation of the resilient member.
- 2. Apparatus as claimed in claim 1, wherein each resilient mounting arrangement includes a compression spring.
- 3. Apparatus as claimed in claim 2, wherein the compression spring is arranged to be compressed to substantially half its length when a surface working head of said surface working head arrangement is arranged to exhibit a force relevant to the surface to be worked.
- 4. Apparatus as claimed in claim 1, wherein a resilient mounting arrangement is arranged to be selectively operative dependent upon the pressure to be exerted through the surface working head arrangement to the surface to be worked.
- 5. Apparatus as claimed in claim 4, wherein the selective operation is achieved through movement of the resilient member within the mounting arrangement and into, and out of, a position in which it can be influenced by increases and decreases in the pressure to be applied by way of the surface working head arrangement.
- 6. Apparatus as claimed in claim 5, and arranged such that the resilient member moves out of an operative position in which it can be deformed once the pressure applied through the surface working head arrangement exceeds a threshold level.
- 7. Apparatus as claimed in claim 6, wherein the resilient mounting arrangement includes a housing provided with an engagement formation arranged to be engaged so as to prevent further biasing of the resilient member as the surface working head arrangement serves to increase the pressure to be applied to the surface being worked.
- 8. Apparatus as claimed in claim 7, wherein the engagement formation comprises a shoulder portion arranged adjacent the resilient member.
- 9. Apparatus as claimed in claim 8, wherein the engagement formation comprises an annular shoulder member disposed around a bore for receiving the resilient member.
- 10. Apparatus as claimed in claim 9, wherein the resilient member is operatively associated with a contact plate for contacting the undersurface of the drive motor shaft adaptor.
- 11. Apparatus as claimed in claim 10, wherein the undersurface of the drive motor shaft arranged to contact the resilient member by way of the contact plate is provided with a chamferred, partially convex, or part spherical surface which serves to assist with a gimbal-like movement of the housing member relative to the drive motor shaft adapter.
- 12. Apparatus as claimed in claim 1, and including a resilient clip means serving to retain the drive motor shaft adapter within the housing.
- 13. Apparatus as claimed in claim 12, wherein the drive motor shaft adapter has an engagement formation arranged to receive the clip means and the transverse cross-section of the drive motor shaft adaptor exhibits corner regions at which the engagement formations are located.
- 14. Apparatus as claimed in claim 13, wherein at least one aperture is formed in a side wall of the cylindrical housing recess/portion and serves to guide the clip means in the region of the shoulder portion of the drive motor shaft adapter.
- 15. Apparatus as claimed in claim 14, and arranged such that outer surfaces of the side walls defining the cylindrical housing recess portion serve as ramp means for at least a portion of the clip means so that as the said portion of the clip means is moved along the ramp means, the clip means is deformed outwardly relative the centre of the drive motor shaft adaptor so as to allow for its removal from the cylindrical housing recess portion.
- 16. Apparatus as claimed in claim 1, and adapted for the releasable mounting of a variety of surface working elements each having different surface working characteristics.
- 17. Apparatus as claimed in claim 16, and including means for selectively varying the pressure exerted by the surface working head and arranged to alter said pressure in response to the working characteristics of the surface working head arrangement.
- 18. Apparatus as claimed in claim 16, and including means for selectively varying the speed at which said head arrangement is driven by said motor in response to the working characteristics.
- 19. Apparatus as claimed in claim 18, wherein the means for selectively varying the speed at which the head arrangement is driven comprises a selective plurality of gear arrangements having gear ratios determined on the basis of the working operations required.
- 20. Apparatus as claimed in claim 19, wherein the gearing arrangement comprises respective pairs of gears in constant mesh and means for selecting one of said pairs for delivering a drive from a gearbox comprising said selectively plurality of gear arrangements.
- 21. Apparatus as claimed in claim 20, wherein the means for selecting the said one of said pairs comprises dog-clutch means.
- 22. Apparatus as claimed in claim 21, and including means for controlling switching in the gearbox and which is associated with means for selecting the pressure applied by way of the surface working head arrangement and arranged such that the switching of the gearbox is achieved in response to the selection of particular pressure values either above or below one or more threshold values or the selection of specific values.
- 23. Apparatus as claimed in claims 1, and including an actuator arrangement for raising and lowering the surface working head arrangement and mounted between the frame and the surface working head arrangement, and means operatively connected to the surface working head arrangement and arranged to at least partially counteract the force to be exerted via the surface working head arrangement on the surface, and so as to control the pressure exerted by the surface working head arrangement on the surface to a range which includes zero pressure to a pressure corresponding to the weight of the surface working head arrangement.
- 24. A surface working device comprising:a support plate with a horizontal lower surface; and a surface working element with a horizontal upper surface, the upper horizontal surface of the surface working element being mounted to the horizontal lower surface of the support plate to depend from and be located below the horizontal lower surface of the support plate, said support plate including an upper surface, which upper surface has a central region with a recess provided therein for the receipt of, and engagement by, a drive member for rotating the device, wherein the recess includes a formation for receiving a resilient member intended for engagement by the drive member, wherein said formation for receiving the resilient member comprises a further recess formed coaxially with said recess provided at the central region of the support plate, and the further recess serves to determine the maximum deformation of the resilient member.
- 25. A device as claimed in claim 24, wherein the said central region comprises an upstanding region for at least part defining the recess and wherein the depth of the recess is independent of the thickness of the support plate.
- 26. A device as claimed in claim 24, wherein the resilient member comprises a compression spring and is arranged to extend coaxially with the said further recess.
- 27. A device as claimed in claim 24, wherein the recess provided in the central region of the support plate has a substantially hexagonal transverse cross-section and is arranged for receiving a substantially hexagonal head of the drive member.
- 28. A device as claimed in claim 27, wherein the depth of the recess formed in the said central region is at least slightly greater than the height of the hexagonal head of the drive member.
- 29. A device as claimed in claim 28, wherein the said central region of the support plate is arranged to operatively receive a spring retaining clip means which requires deformation to allow the drive head into, or out of, the recess formed within said central region.
- 30. A device as claimed in claim 24, wherein the resilient member is associated with a abutment member for contacting the drive member.
Priority Claims (2)
Number |
Date |
Country |
Kind |
9706074 |
Mar 1997 |
GB |
|
9726030 |
Dec 1997 |
GB |
|
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