U.S. patent application number 10/239519 was filed with the patent office on 2003-08-21 for snow groomer with a variable snowchamber tiller assembly.
Invention is credited to Lassonde, Jean-Philippe.
Application Number | 20030154633 10/239519 |
Document ID | / |
Family ID | 27737038 |
Filed Date | 2003-08-21 |
United States Patent
Application |
20030154633 |
Kind Code |
A1 |
Lassonde, Jean-Philippe |
August 21, 2003 |
Snow groomer with a variable snowchamber tiller assembly
Abstract
A snow tiller (10) suitable for grooming ski hills, trails, or
other areas, provides an adjustable snow housing assembly. A snow
chamber (70) is formed between a ground shaping element (48) that
has a rotatable drum (50) and a trailing finishing element (62)
that is supported by a trailing bar bracket (84, 110, 130). The
shape and/or volume of the snow chamber (70) can be adjusted by
activating a finisher positioning mechanism (72), such as a
hydraulic cylinder, to pivot the trailing bar bracket (84, 110,
130). A pair of connecting bars (98 and 100) from a pivot point
about which the trailing bar bracket (84, 110, 130) pivots in an
arc with respect to the snow surface, thus providing for precise
positional control of the snow chamber (70).
Inventors: |
Lassonde, Jean-Philippe;
(Quebec, CA) |
Correspondence
Address: |
PILLSBURY WINTHROP, LLP
P.O. BOX 10500
MCLEAN
VA
22102
US
|
Family ID: |
27737038 |
Appl. No.: |
10/239519 |
Filed: |
March 3, 2003 |
PCT Filed: |
March 21, 2001 |
PCT NO: |
PCT/CA01/00380 |
Current U.S.
Class: |
37/219 |
Current CPC
Class: |
E01H 4/02 20130101 |
Class at
Publication: |
37/219 |
International
Class: |
E01H 004/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 22, 2000 |
US |
60191114 |
Claims
What is claimed is:
1. A tiller assembly for shaping a surface, comprising: a main
frame; a ground shaping element carried by the main frame; a
finishing element supported by the main frame and arranged to trail
behind the ground shaping element over the surface, wherein a
chamber having a volume is formed between the ground shaping
element and the finishing element; a bracket secured to the
finishing element; and a driven member connected between the main
frame and the bracket that moves the bracket in an arc with respect
to the surface to thereby change the volume of the chamber.
2. The tiller assembly of claim 1, wherein the driven member causes
the bracket to pivot about a point spaced from the bracket.
3. The tiller assembly of claim 1, further comprising a pivot arm
supported by the main frame, wherein the bracket is connected to
the pivot arm and pivots with respect to the pivot arm.
4. The tiller assembly of claim 3, further comprising a connector
having one end pivotally connected to the bracket and another end
pivotally connected to the pivot arm.
5. The tiller assembly of claim 4, wherein the driven member is
movable between a first position and a second position thereby
swinging the bracket with respect to the pivot arm.
6. The tiller assembly of claim 4, wherein the connector includes a
pair of connecting rods both arranged to pivot about pivot axes
substantially parallel to the ground shaping element.
7. The tiller assembly of claim 4, wherein the connector includes a
pair of connecting rods aligned with the driven member.
8. The tiller assembly of claim 4, wherein the connector includes a
pair of connecting rods connected between the bracket and the pivot
arm with four pivot points arranged to define a trapezoid.
9. The tiller assembly of claim 1, wherein the bracket includes an
arch shaped rod.
10. The tiller assembly of claim 1, wherein the bracket includes a
bar spaced from and substantially parallel to a top surface of the
finishing element.
11. The tiller assembly of claim 1, further comprising a connector
disposed between the bracket and the driven member.
12. The tiller assembly of claim 1, wherein the bracket includes a
pair of side walls and a pivot member extending therebetween,
wherein the driven member is pivotally attached to the pivot
member.
13. The tiller assembly of claim 12, further comprising a connector
disposed between the pivot member of the bracket and the driven
member.
14. The tiller assembly of claim 13, wherein the connector includes
a pair of connecting rods and the pivot member includes a pair of
pivot pins, each connecting rod pivotally connected between a pivot
pin and the driven member.
15. The tiller assembly of claim 14, wherein each connecting rod
has opposed ends, the ends arranged to define a trapezoid.
16. The tiller assembly of claim 1, further comprising a trailing
bar connected to the finishing element, wherein the bracket is
coupled to the trailing bar.
17. The tiller assembly of claim 1, further comprising a plurality
of brackets and a plurality of driven members.
18. The tiller assembly of claim 1, further comprising a power
connection on the frame for connection to a power source, the power
connection attached to the driven member.
19. The tiller assembly of claim 1, wherein the driven member is a
hydraulic cylinder.
20. The tiller assembly of claim 1, further comprising a controller
in communication with the driven member that controls movement of
the driven member and thereby controls the volume of the
chamber.
21. The tiller assembly of claim 20, wherein the controller
includes a hydraulic system connected to the driven member.
22. The tiller assembly of claim 1, wherein the ground shaping
element includes a rotatable drum with cutting teeth.
23. The tiller assembly of claim 1, wherein the tiller assembly is
a snow tiller and the ground shaping element is a rotatable drum
with a cover.
24. The tiller assembly of claim 1, wherein the finishing element
is a flexible mat with finishing formations that create a texture
in the surface.
25. The tiller assembly of claim 1, in combination with a
vehicle.
26. The tiller assembly of claim 25, wherein the vehicle is a
tracked vehicle and the tiller is a snow tiller.
27. A tiller assembly for shaping a surface, comprising a main
frame; a ground shaping element carried by the main frame, wherein
the ground shaping element has a longitudinal axis; a finishing
element supported by the main frame and arranged to trail behind
the ground shaping element over the surface, wherein a chamber
having a volume is formed between the ground shaping element and
the finishing element; a pivot arm extending outward from the
ground shaping element; a bracket secured to the finishing element;
a pivoting connector pivotally attached between the bracket and the
pivot arm; and a driven member connected between the main frame and
the bracket that causes the bracket to pivot with respect to the
pivot arm to thereby change the volume of the chamber.
28. The tiller assembly of claim 27, wherein the pivoting connector
includes a pair of connecting rods.
29. The tiller assembly of claim 28, wherein the connecting rods
are aligned in a direction substantially perpendicular to the
longitudinal axis.
30. The tiller assembly of claim 28, wherein each connecting rod
has a first end and a second end, wherein the first ends of
adjacent connecting rods are spaced apart at a first distance and
the second ends of adjacent connecting rods are spaced apart at a
second distance different from the first distance.
31. The tiller assembly of claim 27, wherein the bracket includes
an arch shaped rod.
32. The tiller assembly of claim 27, wherein the bracket includes a
generally horizontal bar and a pair of support legs that space the
bar from the finishing element, the driven member being attached to
the bar.
33. The tiller assembly of claim 27, further comprising a trailing
bar connected to the finishing element, wherein the bracket is
coupled to the trailing bar.
34. The tiller assembly of claim 27, further comprising a power
connection on the frame for connection to a power source, the power
connection attached to the driven member.
35. The tiller assembly of claim 27, wherein the driven member is a
hydraulic cylinder.
36. The tiller assembly of claim 27, further comprising a
controller in communication with the driven member that controls
movement of the driven member and controls the volume of the
chamber.
37. The tiller assembly of claim 27, wherein the finishing element
is a flexible mat with finishing formations that create a texture
in the surface.
38. The tiller assembly of claim 27, further comprising a plurality
of brackets and a plurality of driven members.
39. The tiller assembly of claim 27, wherein the tiller assembly is
a snow tiller and the ground shaping element is a rotatable drum
with a cover.
40. The tiller assembly of claim 27, in combination with a
vehicle.
41. The tiller assembly of claim 40, wherein the vehicle is a
tracked vehicle and the tiller is a snow tiller.
42. A method of working the surface of the ground, comprising:
providing a tiller assembly having a ground shaping element and a
finishing element with a chamber defined therebetween, wherein the
finishing element is supported by a bracket; tilting the finishing
element to change the volume of the chamber by moving the bracket
in an arc with respect to the surface of the ground; operating the
ground shaping element to grind the surface; and driving the tiller
assembly across the surface to drag the finishing element over the
surface and provide a finished texture to the ground.
43. The method of claim 42, wherein tilting the finishing element
includes driving a hydraulic cylinder by selectively energizing a
hydraulic fluid in the hydraulic cylinder.
44. The method of claim 42, wherein tilting the finishing element
includes moving the bracket about a pivot point spaced from the
bracket.
45. The method of claim 42, wherein driving the tiller includes
towing the tiller assembly from a vehicle.
Description
[0001] This application is a continuation-in-part application of
International application No. PCT/CA00/01501 filed Dec. 15, 2000,
the contents of which are hereby incorporated by reference.
FIELD OF INVENTION
[0002] This invention relates to ground working devices,
particularly snow grooming devices. More specifically, this
invention relates to tillers for use with snow grooming vehicles
for ski slopes.
BACKGROUND OF THE INVENTION
[0003] Ground working devices have long been used in agriculture to
break up and till earth. Such devices, known as tillers, typically
include a trailing assembly that has a rotating ground loosening
unit and a smoothing or leveling board. The loosening unit can be
subdivided into subassemblies connected by joint(s) to accommodate
the changing contours of the ground.
[0004] This general concept has been adopted and modified to groom
snow, especially ski slopes. Snow making and snow grooming has
become an essential part of any successful ski center due to
increased skier traffic, longer ski seasons, and variable weather
conditions. As a result, snow groomers are becoming more
sophisticated. Typical snow grooming vehicles are tracked vehicles,
which provide traction across the snow and up and down hills. These
vehicles are equipped with a number of attachments or devices to
help in the snow grooming process.
[0005] Generally, a tracked snow vehicle has an inverted V-shaped
or U-shaped plow on the front of the vehicle that collects snow
from areas where there is too much and moves it to areas which are
worn. The front implement can also rip up icy and encrusted slopes
to create or renew trails and remove glacier surface ice. The front
implement can include a toothed bar that is lowered by a pivoting
ram to break up hard, icy slopes into large lumps. The tracks of
the vehicle assist in breaking up the lumps. Attached to the rear
of the vehicle is a snow tiller that grinds the lumps and surface
and then smoothes the surface of the snow to restore it to skiing
condition.
[0006] Snow tillers are frequently equipped with a drum formed as a
rotating blade and a finishing member that trails behind the rotor.
A snow chamber or housing is formed immediately behind the drum and
under and in front of the finishing member to hold a volume of snow
so that it can be worked more extensively by the tiller. The
finishing member is usually a flexible mat or mats having grooved
finishing elements provided at the rear of the tiller assembly to
provide the final snow surface conditioning by smoothing or,
alternatively, to provide a "corduroy" texture to the surface of
the tilled snow.
[0007] By controlling the angle at which the finishing member is
supported, the volume of the snow chamber can be changed.
Accordingly, the amount of snow held in the snow chamber during
tilling can be controlled and varied based on current snow
conditions. For example, if the snow chamber is enlarged, snow held
within the chamber can be worked by the tiller for a longer period
of time. An example of a variable snow chamber is disclosed in U.S.
Pat. No. 5,067,263, in which the angle of the trailing bar mounted
on the flexible membrane that forms the outer bounds of the snow
chamber is varied to retain more or less snow within the snow
chamber. The disclosure of U.S. Pat. No. 5,067,263 is incorporated
into this application by reference.
[0008] A prior art assembly similar to U.S. Pat. No. 5,067,263 is
shown in FIGS. 11 and 12. A tiller 200 is typically driven by a
vehicle such as a snow groomer (not shown). Tiller 200 includes a
main frame 238 that is supported by the vehicle. Main frame
supports a pair of cross beams 244 that hold a ground shaping
element 248 that has a cutting drum 250 and a cover 252. Cutting
drum 250 is driven to rotate thereby breaking up ice chunks, hard
pack and other lumps of snow or ice to produce a softer, more
desirable and uniform surface. A finishing element 262 extends from
ground shaping element 248 and is formed as a flexible mat that
smoothes out the ground ice and snow. A snow chamber 270 is formed
between the ground shaping element 248 and the finishing element
262 in which snow and ice is held while the cutting drum 250 works
the ice and snow. Finishing element 262 has a trailing bar 280 that
is supported by a positioning mechanism 272 that includes a
hydraulic cylinder 278 and a support bar 276. As seen in FIGS. 11
and 12, trailing bar 280 can be tilted backward and forward by
actuating hydraulic cylinder 278 within a limited range of
movement.
[0009] Known variable geometry snow tillers produce acceptable, and
at times even outstanding, snow surface finishes over a wide range
of snow conditions. However, moist to wet snow conditions pose
special considerations and handling requirements. In particular, it
is difficult to process wet or moist snow effectively once it has
been through the cutting drum, resulting in an unacceptable snow
surface finish.
[0010] The inventor of this application believes that the poor
performance results when snow is held too long in the variable
geometry snow chamber. Since moist to wet snow is the ideal type of
snow to make snowballs, snow tumbling in the snow chamber, defined
as the area between the cutting drum and trailing bar, begins to
agglomerate into lumps. These lumps continue to increase rapidly in
size until the entire chamber section is filled with lumps. After
initially filling the snow chamber, the lumps continue to become
more and more compacted and correspondingly harder. The trailing
bar tends to retain the lumps until they reach a high degree of
compaction, producing lumps of almost rock-like hardness. The
growing volume of these hard lumps of compacted snow eventually
forces the lumps to pass under the trailing bar and be pressed into
the groomed snow surface. The presence of these hard lumps, which
may be of substantial size, results in a groomed snow surface that
is not satisfactory for most snow sports. Therefore, there is a
need to better control the assembly under such snow conditions to
address the problem of forming hard lumps during snow
conditioning.
SUMMARY OF THE INVENTION
[0011] An aspect of this invention is to provide a tiller that can
be modified in response to snow conditions.
[0012] Another aspect of this invention provides a tiller having a
snow chamber in which the volume and/or geometry can be varied.
[0013] A further aspect of this invention provides a snow chamber
that can be finely adjusted.
[0014] An additional aspect of this invention comprises providing a
controller that allows an operator to selectively change the
chamber shape for grooming.
[0015] Embodiments of this invention provide a tiller assembly for
shaping a surface, comprising a main frame, a ground shaping
element carried by the main frame, and a finishing element
supported by the main frame and arranged to trail behind the ground
shaping element over the surface. A chamber having a volume is
formed between the ground shaping element and the finishing
element. A bracket is secured to the finishing element, and a
driven member connected between the main frame and the bracket that
moves the bracket in an arc with respect to the surface to thereby
change the volume of the chamber.
[0016] This invention also provides a tiller assembly for shaping a
surface, comprising a main frame, a ground shaping element carried
by the main frame, and a finishing element supported by the main
frame and arranged to trail behind the ground shaping element over
the surface. A chamber having a volume is formed between the ground
shaping element and the finishing element A pivot arm extends
outwardly from the ground shaping element, and a bracket is secured
to the finishing element. A pivoting connector is pivotally
attached between the bracket and the pivot arm. A driven member is
connected between the main frame and the bracket that causes the
bracket to pivot with respect to the pivot arm.
[0017] This invention additionally provides a tiller assembly for
shaping a surface, comprising a main frame, a ground shaping
element carried by the main frame, and a finishing element
supported by the main frame and arranged to trail behind the ground
shaping element over the surface. A chamber having a volume is
formed between the ground shaping element and the finishing
element. A bracket is secured to the finishing element. A pivoting
connector has two ends with one end pivotally attached to the
bracket. A driven member is connected between the main frame and
the other end of the pivoting connector that causes both ends of
the pivoting connector to pivot and swing the bracket, thereby
changing the volume of the chamber.
[0018] The invention further relates to a method of working the
surface of the ground, comprising providing a tiller assembly
having a ground shaping element and a finishing element with a
chamber defined therebetween, wherein the finishing element is
supported by a bracket. The method includes tilting the finishing
element to change the volume of the chamber by moving the bracket
in an arc with respect to the surface of the ground. The ground
shaping element is operated to grind the surface, and the tiller
assembly is driven across the surface to drag the finishing element
over the surface and provide a finished texture to the ground.
[0019] It is to be understood that the invention described herein
can be varied in a number of ways and is not restricted to the
particular embodiments described herein. The invention is intended
to generally include a variety of equipment arrangements wherein
the volume and shape of the snow housing can be selectively set and
controlled.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The invention will be described in greater detail in
conjunction with the following drawings wherein:
[0021] FIG. 1 is a side view of a tracked vehicle with a tiller in
accordance with an embodiment of the invention attached
thereto;
[0022] FIG. 2 is an enlarged partial side view of the tiller shown
in a first position in accordance with an embodiment of the
invention;
[0023] FIG. 3 is an enlarged partial side view of the tiller of
FIG. 2 shown in a second position;
[0024] FIG. 4 is a schematic view of the tiller of FIG. 2 showing
the change between the first and second positions;
[0025] FIG. 5 is a partial perspective view of a support assembly
for the tiller in accordance with an embodiment of the
invention;
[0026] FIG. 6 is a partial perspective view of another support
assembly for the tiller in accordance with an embodiment of the
invention;
[0027] FIG. 7 is a partial perspective view of the preferred
support assembly for the tiller in accordance with another
embodiment of the invention;
[0028] FIG. 8 is a side view of the tiller in the first position
according to the embodiment shown in FIG. 7;
[0029] FIG. 9 is a side view of the tiller in the second position
according to the embodiment shown in FIG. 7;
[0030] FIG. 10 is schematic side view of the tiller moving between
the first and second positions in accordance with the preferred
embodiment of FIG. 7;
[0031] FIG. 11 is a partial side view of a tiller in accordance
with the prior art in which the tiller is in a first position;
and
[0032] FIG. 12 is a partial side view of the prior art tiller of
FIG. 7 in a second position.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
[0033] The invention is described with particular reference to a
snow groomer including a snow tiller. The detailed description of
the snow groomer as the vehicle with which the tiller is used is
provided for purposes of illustration only and is not intended to
be a limiting embodiment.
[0034] FIG. 1 shows an assembly 1 including a ground working
vehicle 12 with a tiller 10 attached thereto in accordance with an
embodiment of the invention. Ground working vehicle 12 in this case
is a tracked vehicle, commonly called a snow groomer, that
functions as the power source for tiller 10.
[0035] Vehicle 12 has a cab 14, in which an operator can sit and
drive the vehicle and operate the controls for the various
implements connected to the vehicle. The drive mechanism for
vehicle 12 is a pair of rotatable tracks 16 with one track 16
disposed on each side of the vehicle body. Vehicle 12 has a front
implement 18, in this case a hydraulically controlled plow 20, and
a rear implement, which in this case is tiller 10. Vehicle 12 is
especially adapted for driving on snow, but of course could be any
type of vehicle. Additionally, a variety of accessories and
attachments may be used with the vehicle either on the front or
rear, including for example a front digger rather than a front
plow. Further, if desired, only a rear implement could be used.
[0036] Vehicle 12 is equipped with appropriate attachment
mechanisms 22 and 24 on the front and/or back of the vehicle,
respectively, to provide power and structural connections to such
front and/or rear implements. Cab 14 includes a control panel 26
connected to a controller, shown schematically in FIG. 1, to
control operations of the vehicle and its implements. Of course, if
desired or if a different type of vehicle is used, control panel 26
could be provided elsewhere on the vehicle, on the tiller itself,
and/or at multiple locations. The control panel 26 can be of any
known form suitable for actuating the implements and selecting
various functions for the implements. The controller can be
implemented in any known type of operating control system. For
example, the control logic could be hard wired into the central
logic system of the vehicle or implemented as a plug-in or through
software installation.
[0037] Attachment mechanism 24 is an articulated joint for
connecting tiller 10 to a power source, in this case vehicle 12,
and can be a three point hitch 26 and a hydraulically controlled
lifting mechanism 28. The hydraulic lifting mechanism 28 includes a
main tow bar 30 and a driven hydraulic cylinder 32 that can be
controlled to raise tiller 10 from the surface of the ground. A
hydraulic tilt cylinder 34 is provided to change the depth at which
tiller 10 works the surface. Any other suitable connecting
mechanism could also be employed and could optionally include the
lifting mechanism, if desired. Other desired connections could be
used including electric, pneumatic, optical or communication
connections to control and operate different operating functions of
the tiller.
[0038] Tiller 10 includes a support frame 36 connected to the
lifting mechanism 28. The support frame 36 has a main horizontal
frame 38 in the form of a box beam, I beam, channel beam or any
strong structural beam type member. An upper snow guard 40,
typically two separate panels, is attached to main frame 38 to
prevent snow from blowing from the tracks 16 over the tiller
assembly 10 onto the finished snow surface. A pair of cross beams,
of which only one beam 44 is shown, extend rearwardly from main
frame 38 and support a ground shaping element 48.
[0039] Ground shaping element 48 includes a rotatable drum 50 with
cutting teeth and a cover 52. Cover 52 creates a housing for
rotatable cutting drum 50 and includes end caps 51. Cover 52, which
is best seen in FIG. 7, can form a single housing or a series of
housings along the length of ground shaping element 48. Ground
shaping element 48 has a longitudinal axis about which drum 50
rotates and is oriented perpendicular to a direction in which
tiller 10 is driven. A drive train, in this case in the form of a
gear box, is connected to rotatable drum 50 to selectively rotate
drum 50 to grind or otherwise shape the ground or material beneath
drum 50. Drum 50 rotates to break up ice chunks, hard pack, or
other undesirable types of snow, or ice as the case may be, to
produce a softer, more desirable surface.
[0040] Extending from cover 52 of ground shaping element 48 is a
finishing element 62. Finishing element 62 includes a flexible mat,
for example a rubber or heavy polymeric sheet, that is positioned
to drag behind ground shaping element 48. The design, surface, and
weight of the mat as it being drawn across the surface, smoothes
the ground out behind ground shaping element 48 after the ground
has been cut or shaped. It is preferred that the trailing mat be
flexible at anticipated operating temperatures so that it may more
closely follow the contour of the surface of the ground.
[0041] The outer edge of finishing element 62 can be shaped, for
example with serration, and/or can include finishing formations 66,
which are blocks or strips attached to the lower surface of or
molded into the flexible mat, both of which create texture in the
finished surface when tiller 10 is driven across the surface of the
ground. Finishing element 62 may also be formed as a board or
membrane that optionally has rows of finishing elements, preferably
formed of polyethylene or plastics but may also be formed of steel,
fiberglass, or other suitable materials in a variety of profiles.
The texture formed in the snow surface by finishing element 62 is
known as a "corduroy" surface, especially in the snow grooming
field, and includes a series of striations formed on the surface of
the snow. The texture can be varied, of course, by varying the type
and/or shape of edge 64 of finishing element 62 and/or the shape,
type and size of finishing formations 66.
[0042] A snow chamber 70 is defined beneath cover 52 and between
rotating drum 50 and finishing element 62. Snow is retained within
snow chamber 70 and worked by rotating drum 50 before being
smoothed by finishing element 62. As described below, the shape,
and hence the volume, of the snow chamber 70 can be varied in
accordance with this invention.
[0043] A finisher positioning mechanism 72 is provided to rotate
finishing element 62 relative to the ground and to adjust the shape
of finishing element 62 so as to control the volume of the snow
chamber 70. Preferably, two finisher positioning mechanisms 72 are
provided on each side of tiller 10. However, there is no specific
number of mechanisms required, and any number from one or more than
two is possible. Finisher positioning mechanism 72 extends from
cover 52, or as an extension of cross beams 44, and is secured to
finishing element 62 by a trailing bar 80, which is preferably
semi-rigid so as to conform to the terrain over which the tiller
passes.
[0044] As described in detail below, finisher positioning mechanism
72 includes a driven member 78, such as a hydraulic cylinder, and a
trailing bar bracket 84 that is pivotally attached to an extension
of main frame 38 so as to allow trailing bar 80 to pivot with
respect to main frame 38. As described herein, trailing bar bracket
84 is preferably supported by a pivot arm 76, which is attached to
housing or cover 52, and adjusted by finisher positioning mechanism
72.
[0045] As seen in FIGS. 2 and 3, trailing bar 80 is secured to
finishing element 62 on one side of the mat with a smoothing board
82 secured to the other side of the mat. It is possible to use only
the trailing bar 80 without smoothing board 82. It is also possible
to use only smoothing board 82 as the attachment point through the
mat for finisher positioning mechanism 72.
[0046] In this embodiment, trailing bar 80 is supported by trailing
bar bracket 84. As seen in FIG. 5, bracket 84 preferably includes a
generally horizontal bracket bar 86 and a pair of angled support
legs 88 and 90, respectively. Bracket bar 86 can be formed as a box
beam for strength or can have any conventional structural shape,
including an I-beam or plate. Similarly, support legs 88 and 90 are
shown as plate-like brackets, but can be formed of any known
structural shape. As seen in FIGS. 2 and 3, finisher positioning
mechanism 72 is secured to bracket bar 86. (In FIG. 5, finisher
positioning mechanism 72 is removed to more clearly show the
trailing bar 80 support structure.)
[0047] As noted above, bracket bar 86 is also secured to pivot arm
76 that extends outwardly from ground shaping element 48. In this
case, pivot arm 76 extends from cover 52 and is secured to cross
beam 44, which is supported by main frame 38. As seen in FIGS. 2
and 3, pivot arm 76 is secured at two fastening points 92 and 94 to
cross beam 44 so that pivot arm 76 extends rigidly outward and
cannot move. Pivot arm 76 is coupled to bracket bar 86 with a
support bracket 96 that extends from below bracket bar 86, as seen
in FIG. 5, and rotatably supports a pair of rigid connecting rods
98 and 100.
[0048] Connecting rods 98 and 100 are arranged in longitudinal
alignment with respect to the front to back direction of the
tiller. Connecting rods 98 and 100 are rotatably supported at each
end. For example, connecting rod 98 is rotatably supported by
support bracket 96 at one end and by pivot arm 76 at the other end.
Connecting rod 100 is similarly supported. Pivot arm 76 is
configured with a pair of spaced, parallel support fingers 102 and
104 at its outwardly extending end to support the ends of
connecting rods 98 and 100 therebetween. Of course, any secure form
of attachment can be provided at any point on trailing bar bracket
84 that allows relative pivotal movement between pivot arm 76 and
trailing bar bracket 84.
[0049] As seen in FIGS. 2-4, the lower ends of connecting rods 98
and 100 are secured to pivot arm 76 adjacent to each other while
the upper ends of connecting rods 98 and 100 are secured to support
bracket 96 spaced from each other. By this, connecting rods are not
arranged parallel to each other along their length. As seen in FIG.
2, connecting rod 98 is also longer than connecting rod 100.
However, the connecting rods could be the same length or connecting
rod 100 could be longer than connecting rod 98. By any of these
arrangements, the four ends of the connecting rods 98 and 100
define the corners of a trapezoid. Ideally, the trapezoid is shaped
to minimize the amplitude experienced by the trailing bar 80 when
it is adjusted.
[0050] Alternatively, as seen in FIG. 6, the trailing bar 80
support structure can be a U-shaped bracket 110 with upstanding
side walls 112 and 114 and a connecting web 116 that is directly
secured to trailing bar 80. In this case, pivot pins 118 and 120
are provided to support the upper ends of connecting rods 98 and
100. The lower ends of connecting rods 98 and 100 are secured at
pivot points to a channel bracket 122. Channel bracket 122 is used
in place of pivot arm 76 and is directly secured to finisher
positioning element 72. The relative relationship between
connecting rods 98 and 100, as described above with respect to FIG.
5, remains the same. Bracket 110 can be used alone or in
combination with bracket 84. When used in combination, bracket 110
can be used as a stabilizer. In this case, for example, a pair of
brackets 84 can be secured to trailing bar 80 along with three
brackets 110 alternated at each side of bracket 84 to provide a
consistent shape to snow chamber 70.
[0051] In operation, finisher positioning mechanism 72 is operated
to selectively move trailing bar 80 with respect to the main frame
38 of tiller 10. First, driven member 78 is actuated. Any driving
force member is suitable for use in this invention, for example a
gear driven rod or ratchet assembly, pneumatic cylinders, motor
driven devices or rotating devices, used singly or in combination.
However, in this embodiment, a hydraulic cylinder is used as the
driven member 78. So, hydraulic cylinder 78 is actuated using any
suitable control system and hydraulic assembly. Cylinder 78 can be
driven using a separate hydraulic system or can be driven using the
hydraulic system in place in the snow groomer. For example, parent
PCT application PCT/CA00/01501 describes several suitable hydraulic
control schemes that vary from manual to automatic.
[0052] To change the volume and/or shape of the snow chamber 70,
the operator of the vehicle 12 actuates hydraulic cylinder 78 to
move between a first position, shown in FIG. 2, and a second
position, shown in FIG. 3, and vice versa The terms first and
second are used only as relative terms and do not imply a
particular order. The first position is the open or fully extended
position in which the rod of the hydraulic cylinder 78 is fully
extended The second position is the closed or filly retracted
position in which the rod of the hydraulic cylinder 78 is full
retracted.
[0053] Referring to FIG. 4, the finisher positioning mechanism is
shown moving from the first position (in dotted lines) to the
second position. As can be seen in FIG. 4, because of the
arrangement of connecting rods 98 and 100, with the trapezoidal
configuration and four pivot points, retracting hydraulic cylinder
78 causes bracket bar 86 (to which the end of hydraulic cylinder is
connected) to move in an arc .alpha.. This causes trailing bar 80
to also move in an arc with respect to the surface of the ground,
in this case snow. Moving trailing bar 80 causes finishing element
62 to change shape. As seen in FIG. 4, finishing element 62 changes
from a relative straightened profile to a convex profile with
respect to the snow surface, thus reducing the volume of snow
chamber 70. Pivoting trailing bar 80 in an arc allows a greater
scope of control in controlling the volume of snow chamber 70. By
the arrangement described above, trailing bar 80 in effect swings
around pivot bar 76 in response to movement of hydraulic cylinder
78.
[0054] The embodiment shown in FIG. 6 works in the same way in that
trailing bar 80 swings from bracket 110 in response to movement of
hydraulic cylinder 78.
[0055] Referring to FIGS. 7-10, which show the preferred embodiment
of this invention, trailing bar 80 is supported by an arch shaped
rigid bracket 130. Bracket 130 is formed of a metal rod or tube,
for example, bent into an arch shape with each end of the arch
secured to a channel bracket 132 and 134, respectively. Any number
of brackets 130 may be used along the length of trailing bar 80.
For example two to four brackets may be used. At the apex of the
arch bracket 130, a support bracket 136, similar to support bracket
96 in the embodiment shown in FIG. 3, is provided that connects
arch 130 to driven member 78 and pivot arm 76. Between pivot arm 76
and support bracket 136, connecting rods 98 and 100 extend. As
described above, each connecting rod 98 and 100 is rotatably
supported at its respective ends, which are arranged to define a
trapezoid.
[0056] FIG. 8 shows the driven member 78 in the fully extended
position, which moves the finisher positioning mechanism 72 into
the first position. Due to the trapezoidal arrangement of
connecting rods 98 and 100, trailing bar 80 is tilted with respect
to the snow surface. FIG. 9 shows the driven member 78 in the fully
retracted position, which moves the finisher positioning mechanism
72 into the second position. As seen in FIG. 10, actuation of
driven member 78 swings support bracket 136 in an arc, pivoting
driven member 78 with respect to cross beam 44 and causing
connecting rods 98 and 100 to rotate with respect to pivot arm 76.
As a result, bracket 130 swings and tilts trailing bar 80.
[0057] To help maintain the shape of snow chamber 70, a pressure
plate 140 is used in this embodiment to press the end of finishing
element 62 down and reduce bulging in the snow chamber 70. Snow
chamber 70 is shown with a relatively flat upper surface in FIG. 8,
which is an ideal shape. However, in practice, chamber 70 typically
has an upper concave shape that bulges upwardly due to snow
accumulation within chamber 70. Pressure plate 140 extends from
housing or cover 52 and can optionally be biased downwardly as seen
in FIG. 9. A conventional biasing mechanism can be used, such as a
spring hinge, that allows pressure plate 140 to pivot upwardly when
trailing bar 80 is tilted upward and snow chamber 70 is enlarged
and then return to a downward oriented position. Of course,
pressure plate 140 can be used with any of the embodiments
disclosed herein.
[0058] A tiller designed and controlled in accordance with any of
the above schemes can be used to groom surfaces, for example ski
trails, in controlled profiles and be responsive to variable snow
and weather conditions. The degree of work that the tiller does on
the snow can be controlled by controlling the shape and volume of
the snow housing. By this, snow grooming can be controlled in
different areas of the trail and at different times by the operator
during grooming.
[0059] In addition to the snow housing adjustments, the tiller may
be provided with a range of other adjustments to address differing
snow conditions on the same hill on the same day in different
areas. Preferably, the operator would be able to activate all of
the controls to move the various cylinders or make other
adjustments to the operation of the tiller from the security of the
cab. It is possible to arrange the system so that an operator would
only need to glance in the rear view mirror to discern if the
correct quantity and quality of snow is being left behind.
[0060] Further, this invention can be used in combination with the
profile adjustment system disclosed in parent PCT application
PCT/CA00/01501 by using the same or a different control scheme.
[0061] It is to be understood that the essence of the present
invention is not confined to the particular embodiments described
herein but extends to other similar devices that employ a variable
snow housing assembly to control snow conditioning
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