Note: Descriptions are shown in the official language in which they were submitted.
1
Folding blade for a clearing apparatus with a blade
Technical area
The invention relates to a folding blade for a clearing apparatus with a
clearing blade,
comprising a folding bar, a lever mechanism for pivotally mounting the folding
bar on a base
part of the clearing blade, and a spring element for arrangement between the
base part and
the lever mechanism, for returning the folding bar to an initial position in
which the folding
bar forms an extension of a blade plate of the clearing blade. The lever
mechanism is
designed in such a way that the folding bar is pivotable from the initial
position to a retracted
position along a first pivoting path by overcoming a spring force of the
spring element, and
the folding bar is pivotable from the retracted position to the initial
position along a second
pivoting path due to the spring force. The invention further relates to a
clearing blade having
such a folding blade.
State of the art
Folding blades of this type are known. They are used in particular for
clearing equipment of
snow clearing machines. However, they are also used for clearing equipment of
municipal
vehicles, rail vehicles or tractors, whereby the clearing equipment can be
designed as
integrated components of the respective vehicles or as exchangeable
attachments.
Originally, there are two types of rotating snow clearing machines, the snow
blower and the
snow tiller. The snow blower has a large paddle wheel, the axis of which is
oriented in the
direction of travel. The diameter of the paddle wheel determines the clearing
width. The
rotating blades of the paddle wheel carry away the snow at the front and
transport it to the
outside with the help of centrifugal force. There, the snow is then ejected
through an
opening. The snow tiller has rollers whose axes are oriented at a right angle
to the direction
Date recue/Date received 2023-05-08
2
of travel. The rollers have reels that are arranged in a spiral around the
rollers and run
inwards as a result of the rotary motion. The rotating reels now carry away
the snow and
transport it to the center of the machine. There it is in turn ejected through
an opening.
The dual-stage snow blower combines these two systems in one machine. The
cutting reels
are mounted in front, and the blower wheel is located behind them. The cutting
reels and
blower wheel are optimally matched to each other by gears and ratios in order
to be able to
work efficiently. This system combines the advantages of the cutting reels,
which can
remove the snow better and allow a greater width with a lower overall height,
with those of
the blower wheel, which allows a further ejection with increased snow mass.
In order to cushion the impact when the clearing blade hits an obstacle on the
ground and
to make it easier to drive over the obstacle, the clearing blade is equipped
with a folding
blade. This is often referred to as a "collision safety device". Folding
blades have one or more
folding bars that are pivotably mounted on a base part of the clearing blade.
The folding
blades are usually designed as wear parts, so-called clearing blades. Because
they are in
constant contact with the ground surface to be cleared during operation, they
wear out and
have to be replaced when a certain degree of wear is reached.
Such a folding blade is available, for example, on dual-stage snow blowers
from the applicant
Zaugg AG Eggiwil, Eggiwil, Switzerland, e.g. the model SF 7270 KS. The folding
bar is split in
the middle so that the two elements can trigger separately on the left or
right, depending on
the point of impact of the obstacle. Both elements are pivoted on a base part
of the clearing
blade via a horizontal hinge axis running transverse to the direction of
travel. When they hit
an obstacle, they are pressed backwards. The restoring force is provided by a
hollow rubber
spring, which is installed between the base part and the folding bar and is
compressed when
folded back. Other suppliers also offer snow removal vehicles with similarly
designed
collision guards, e.g. Westa GmbH, Weitnau, Germany for their 6570, 7370 and
750 snow
blowers.
Folding blade systems are also known for snow plows. The folding blade forms
the lowest
section of the snow plow blade. Typically, part of the folding assembly
deflects forward, i.e.
in the direction of travel. This is not a problem in the case of a snow plow,
but corresponding
Date recue/Date received 2023-05-08
3
solutions cannot be transferred to snow blowers because the rotating cutting
reels are
located in front of the blade and the foldable element would collide with
them.
Conventional folding blades improve the clearing result, operating safety and
protect the
cutter and the carrier vehicle when driving over obstacles. However, when the
folding blade
system is triggered, the snow blower can be pushed upwards, causing the cutter
to
"bounce". This causes strong vibrations in the carrier vehicle and impairs the
clearing result
in the area of the obstacle. Furthermore, it can happen that the folding bar
gets stuck in its
retracted position after being released and does not return to its initial
position. In such
cases, the clearing operation must be interrupted. The clearing blade with the
folding blade
is then raised briefly with the aid of the corresponding lifting device of the
carrier vehicle to
allow the folding blade to return to its initial position.
DE 10 256 541 Al (Fritz Sperber GmbH) proposes a mechanism to prevent the
folding blade
from bouncing. The corresponding folding bar is guided in such a way that it
does not take
up any additional space below the base part of the clearing blade when it is
pivoted back.
The mechanism creates a virtual pivot axis for the folding bar, which is
located in front of
the clearing blade. It includes a linkage with two arms or levers that are not
parallel to each
other and, if necessary, a cam track that serves as a guide during the
pivoting movement
and can be arranged in a rib or a stiffening plate. The mechanism is designed
to swing back
after hitting an obstacle and return to the initial position along the same
predetermined
pivoting path.
This mechanism improves the pivoting back of the folding bar after hitting an
obstacle.
However, problems can still arise, particularly when returning to the initial
position,
especially if the folding bar comes into contact with the material to be
cleared again during
return, which can lead to complete return being prevented for a longer period
of time. This
in turn leads to a deteriorated clearing result.
Date recue/Date received 2023-05-08
4
Summary of the invention
It is the problem of the invention to create a folding blade belonging to the
technical field
initially mentioned, which enables an improved return of the folding bar and
thus a better
clearing result.
The solution to the problem is defined by the features of claim 1. According
to the invention,
the lever mechanism is designed in such a way that the second pivoting path is
different
from the first pivoting path.
This means that the lever mechanism offers at least two degrees of freedom in
at least one
or more partial sections of the path between the initial position and the
retracted position.
The partial sections can extend along the path or be very short in the manner
of a switch or
branch. In particular, due to the different triggering of the first pivoting
path - by contact with
an obstacle that must be overcome by the folding bar- and the second pivoting
path - by the
spring force of the spring element -, in practice there are also actually
different movements
when pivoting back on the one hand and when resetting on the other. As a
result, during a
complete cycle, each point of the folding bar moves from the initial position
to the retracted
position and back to the initial position along a closed curve that includes a
non-zero area.
In particular, in the vicinity of one or both end positions, the two pivoting
paths may coincide,
i.e., in such a section of the pivoting paths there is only one degree of
freedom.
The initial position is characterized in that the folding bar forms an
extension of the blade
plate of the clearing blade. In particular, the front main surface of the
folding bar in this
position lies essentially in the same plane as the front surface of the blade
plate along the
contact line between the clearing blade and the folding bar. Generally, the
folding bar in this
position has a positive pivot angle, i.e., its lower free end is located
forward in the direction
of travel.
The retracted position can be defined by an end stop. In practice, however,
the folding bar
does not have to be pivoted back to this stop every time an obstacle is
overcome. In the
case of smaller obstacles, resetting can already take place before the end
stop has been
reached. Nevertheless, the lever mechanism should preferably be designed in
such a way
Date recue/Date received 2023-05-08
5
that different pivoting paths are also provided in this case. This is
particularly the case if the
first pivoting path and the second pivoting path differ from each other in an
area in the
neighborhood of the initial position. In particular, it is preferred that the
first pivoting path
and the second pivoting path also differ at least in a region in which the
folding bar assumes
a positive pivoting angle.
A single spring element or several spring elements arranged in series and/or
parallel can be
used in the folding blade according to the invention. The spring elements are
preferably
hollow rubber springs. These are insensitive to external influences such as
dirt or ice
formation, have a long service life and relatively low costs. However, other
types of tension
or compression springs, e.g. helical springs, torsion springs or gas springs,
can also be used.
In principle, suitably (actively or passively) controlled hydraulic or
pneumatic cylinders can
also be used as spring elements. The spring element or elements do not have to
be mounted
directly on the base part or on the lever mechanism. In particular, the spring
element can
also interact with the lever mechanism via transmission means, e.g. rods or
cables.
The lever mechanism comprises pivoted levers. In addition, it can also include
elements
such as guides, stops or cable pulls to control or restrict the movement of
the levers.
The base part of the clearing blade comprises the blade plate (the scraper
plate) itself and
any elements permanently connected to the clearing blade, such as stiffening
plates or
profiles, base frames, fastening profiles, etc. Accordingly, the lever
mechanism may engage
one or more of these elements.
The folding blade according to the invention can follow a different pivoting
path when
returning to the initial position than before when overcoming an obstacle.
This means that
the pivoting path can be optimally adapted to the requirements: When pivoting
away from
the initial position, the folding bar should move back so that the obstacle
can be passed
without vertical forces on the clearing blade and without lifting it, if
possible. The return to
the initial position should be as fast and unhindered as possible once the
obstacle has been
passed. The lever mechanism is therefore preferably designed in such a way
that the folding
blade first folds forwards (i.e. in the direction of travel, in particular
until it assumes a positive
pivoting angle) when returning from the retracted position before it is
lowered to the initial
Date recue/Date received 2023-05-08
6
position. Obstacles up to a certain maximum height can thus be overcome
without the
clearing blade bouncing and without interrupting the clearing operation, and
it is ensured
that the folding bar returns to its initial position as quickly as possible
after overcoming the
obstacle and independently during travel, without being prevented from this
return by
external influences, such as contact with the material being cleared.
Taking into account the above-mentioned requirements, the folding blade
according to the
invention can also be designed in such a way that all elements of the folding
blade are
arranged above a lower edge of the clearing blade and at the same time
completely behind
this clearing blade.
The lever mechanism and the spring element of the folding blade according to
the invention
can be designed to save space so that conflicts with other elements of the
clearing
apparatus, e.g. a blower wheel, a suspension of the clearing blade or the
like, are reliably
avoided. Likewise, a lever mechanism can be designed to minimize vibrations
after hitting
an obstacle.
Typically, in the initial position, the folding bar forms a first positive
angle with a vertical line.
This is in particular in the range 30-60 , especially 40-50 . In the retracted
position, on the
other hand, the folding bar assumes a negative angular position so that the
obstacle can be
passed.
Advantageously, therefore, the second pivoting path comprises a first path
region, adjacent
to the retracted position, in which the pivoting path corresponds to a pure
pivoting
movement about a single axis of rotation, and a second path region in which
the pivoting
path corresponds to a superimposition of two pivoting movements about two
spaced axes
of rotation. The second travel range can be directly adjacent to the first
travel range and
extend to the initial position, or there is a further travel range between the
first travel range
and the second travel range and/or the second travel range and the initial
position.
With such a design of the lever mechanism, which allows such a second pivoting
path, it can
thus be achieved that the folding bar is only lowered again during the return
to the initial
position when its pivoting position has reached such a positive value, which
allows further
clearing of the ground and/or allows a deflection of the material to be
cleared onto the
Date recue/Date received 2023-05-08
7
clearing blade. This prevents the folding bar from coming into contact with
the material to
be cleared at an early stage during the return movement and thus pivoting back
again
immediately, which can ultimately prevent resetting for some time.
In preferred embodiments of the invention, the lever mechanism comprises an
elbow lever,
having a first elbow lever element pivotally connected to the base part of the
clearing blade
and having a second elbow lever element connected to the folding bar in a
rotationally fixed
manner, wherein the second elbow lever element and the first elbow lever
element are
hingedly connected to each other and wherein the spring element acts on the
second elbow
lever element.
Both the first elbow lever element and the second elbow lever element can be
connected
directly or indirectly to the base part or the folding bar. The spring element
can act directly
or indirectly on the second elbow lever element. In particular, the folding
blade can comprise
a number of elbow levers which are arranged parallel to one another and
pivotably mount
the folding bar on the base part at positions spaced apart in the transverse
direction.
An elbow lever can be designed to be mechanically very robust, it is
inexpensive and its
function is little susceptible to external influences such as contamination or
icing. The elbow
lever requires comparatively little force deflection, so the mechanical loads
are low. The
deflection takes place smoothly during the pivoting of the folding bar mounted
on the elbow
lever, so that impact effects on the bearing or mounted elements are avoided.
Advantageously, the spring element acts on the second elbow lever element via
a deflection
mechanism. In particular, this means that the spring element can be arranged
directly
behind the clearing blade in a space-saving manner without having to select
the direction of
the force acting on the lever mechanism in an unfavorable manner.
Preferably, the deflection mechanism comprises a deflection lever rotatably
mounted on the
base part and a coupling rod, wherein the spring element and the coupling rod
are mounted
on the deflection lever at spaced pivot points and wherein the coupling rod is
pivotally
connected to the second elbow lever element. A deflection lever of this type
enables the
approximately vertical spring force of a spring element arranged in a space-
saving manner
behind the clearing blade to be deflected into a force acting virtually
horizontally on the
Date recue/Date received 2023-05-08
8
second elbow lever element. This enables reliable resetting of the folding bar
without the
risk of the elbow lever blocking after passing the obstacle due to an
unfavorably acting
spring force.
Instead of or in addition to a deflection lever, the deflection mechanism can
also comprise
a cable pull for deflecting the spring force. A combination of spaced
compression and
tension springs can also be used, for example. Blocking in the retracted
position can also be
prevented by suitable stops, e.g. at the middle joint of the elbow lever.
Compared with these
alternatives, however, the solution with a deflection lever is mechanically
more resilient and
less susceptible to contamination or icing.
Preferably, the deflection lever, the coupling rod and the spring element are
designed in
such a way that a restoring force on the folding bar in the retracted position
is less than in
the initial position. This prevents the folding bar from being pivoted back
from the initial
position due to the force exerted by the material to be cleared, while
preventing unnecessary
resistance when passing an obstacle, i.e. after the pivoting movement has been
"triggered".
A preferred embodiment of the invention comprises a first stop for the first
elbow lever
element arranged on the base part, wherein in the retracted position the first
elbow lever
element rests against the first stop. As long as this contact exists, the
elbow lever has only
one degree of freedom. If the contact is released, after a certain pivoting
movement in the
direction of the initial position, two degrees of freedom result.
Preferably, the folding blade comprises a second stop for the second elbow
lever element
arranged on the base part, the second stop being designed in such a way that
in a section
of the second pivoting path the second elbow lever element is guided by an
outer contour
of the second stop.
For this purpose, the second elbow lever element can in turn have a
specifically shaped
outer contour for interacting with the outer contour of the second stop, e.g.
an outer contour
which, depending on the rotational position of the second elbow lever element,
causes an
alternating distance between the second stop and the articulation of the
spring element
and/or the elbow lever joint, i.e. acts as an eccentric. The specifically
shaped outer contour
Date recue/Date received 2023-05-08
9
of the second elbow lever element is in particular convex in shape and is
formed on the side
of the second elbow lever element facing the second stop.
Particularly preferably, both the first stop and the second stop are present,
and the first stop
limits the second pivoting path in the first path section, adjacent to the
retracted position,
to a pure pivoting movement, while the second stop in the second path section,
adjacent to
the initial position, guides the elbow lever in such a way that two pivoting
movements are
superimposed. The superposition is in particular such that a lowering of the
folding bar in
the direction of the initial position results, in particular while largely
maintaining the pivot
angle of the folding bar. The pivoting angle according to the initial position
is thus essentially
already achieved before the return is completed. Preferably, at least one
third of the lowering
is carried out at least in a travel range adjacent to the initial position,
while the pivot angle
is changed by a maximum of 50 in this range.
The deflection mechanism and the two stops thus ensure overall that the
folding bar swings
back from the retracted position and first folds forward again (to a positive
angular position)
before it sinks again.
Advantageously, in the initial position, the second stop cooperates with the
second elbow
lever element to prevent movement of the folding bar along the first pivoting
path upon a
force acting on the folding bar from a rear side of a main plane of the
folding bar. In
particular, this prevents substantially vertical forces that cannot be caused
by an obstacle
in the direction of travel from triggering the pivoting movement.
In a clearing blade according to the invention, the folding blade is pivotably
arranged on the
clearing blade such that it is pivotable from an initial position, in which
the folding bar of the
folding blade forms an extension of a blade plate of the clearing blade, to a
retracted
position, wherein the folding bar does not enter a path space defined by the
clearing blade
with the folding blade either during pivoting from the initial position to the
retracted position
along the first pivoting path, or during pivoting from the retracted position
to the initial
position along the second pivoting path.
This travel space corresponds to a space below a plane defined by the lower
edge of the
folding bar in the initial position when the blade is mounted on the vehicle
and ready for
Date recue/Date received 2023-05-08
10
operation. This prevents the clearing blade from lifting due to vertical
forces acting on the
folding bar from the ground or obstacle.
In a dual-stage snow blower, the blade preferably has a central receiving
opening for a
blower wheel, and a first folding blade is arranged on a first side of the
receiving opening
and a second folding blade is arranged on a second side of the receiving
opening. In this
case, the folding bars of the first folding blade and the second folding blade
extend into an
area below the receiving opening. The distance between the folding bars in the
transverse
direction is advantageously so small that material to be cleared cannot pass
between the
folding bars in substantial quantities when they are in their initial
position. In particular, the
distance is 5 cm or less.
Further advantageous embodiments and combinations of features of the invention
result
from the following detailed description and the totality of the patent claims.
Brief description of the drawings
The drawings used to explain the embodiment show:
Fig. 1 an oblique view of an embodiment of the folding blade according to
the
invention;
Fig. 2 an exploded view of the lever mechanism of the folding
blade;
Fig. 3A, B a side view of the folding blade in the initial position
and in the retracted
position;
Fig. 4A-E the motion sequence of the folding blade when it pivots back
after hitting an
obstacle; and
Fig. 5A-E the motion sequence of the folding blade during return to
the initial position.
In principle, the same parts are given the same reference signs in the
figures.
Date recue/Date received 2023-05-08
11
Ways to carry out the invention
Figure 1 shows an oblique view of an example of the folding blade according to
the invention,
viewed laterally from the rear. The example relates to a clearing apparatus
with a clearing
blade width of 220 cm, but the folding blade shown can also be used for larger
and smaller
clearing blade widths. The folding blade 1 is arranged on the clearing blade 2
and comprises
two folding bars 6 made of steel. Visible in Figure 1 is the right half of the
clearing blade up
to a central blower wheel housing 3. The left side is essentially symmetrical
to the right side
and comprises its own folding bar 6, whereby in the initial position shown,
the two folding
bars 6 meet in the center up to a distance of approx. 5-10 mm.
The folding blade 1 comprises a base part 5, the folding bar 6 and a lever
mechanism 10, via
which the folding bar 6 is connected to the base part 5 or the clearing blade
2, respectively.
For this purpose, two bearing plates 7, 8 in particular are welded to the
clearing blade 2.
Further bearing points are formed on the base part 5. The lever mechanism 10,
which is
described in more detail below in connection with Figure 2, is acted upon by a
hollow rubber
spring 30 acting as a compression spring and being pivotably mounted on the
clearing blade
2 via a spring guide rod 31. The spring guide rod 31 presses on a contact
roller 41, which is
mounted at one end of a deflection lever 40. The deflection lever 40 is
pivotably mounted
on the clearing blade 2 between the bearing plates 7, 8 and comprises two
parallel,
essentially triangular lever plates 40a, 40b, which are connected to one
another in the region
of the three corners via axles; the contact roller 41 is mounted on one of
these axles. At the
end opposite the contact roller 41, the deflection lever 40 is pivotably
connected to a
coupling rod 45 via an axle 42. This is designed as a steel profile with two
bearing tubes
welded to each end and acts on the lever mechanism 10, as described in detail
below.
The lever mechanism 10 is described in more detail with reference to the
exploded view in
Fig. 2. It consists largely of steel components. It comprises two lever
elements 11, each
comprising two lateral lever arms 11a, 11 b which are connected to each other
by a
connecting plate 11c. The connecting plates 11 c are screwed by means of
several screws
to one each of two fastening plates 6a welded to the folding bar 6 The folding
bars 6 can
thus be easily replaced as soon as they are worn out.
Date recue/Date received 2023-05-08
12
An axle 12 is mounted at the free ends of the lever arms 1 la, 1 lb of each
lever element 11.
Via this, a rotary arm 13 is pivotably mounted at its first end on the lever
element 11. The
rotary arm 13 comprises a bearing tube 13a and two lever arms 13b, 13c
arranged non-
rotatably on the bearing tube 13a. The bearing tube 13a accommodates the axle
12. The
lever element 11 and the rotary arm 13 thus form an elbow lever, and the axle
12 forms the
axis of rotation of the elbow lever. At the second end of the rotary arm 13,
an axle 14 is
mounted on the lever arms 13b, 13c. Via this, the rotary arm 13 is pivotably
mounted on the
base part 5 of the folding blade 1 (see Fig. 3A, 3B).
A further axle 46 is mounted between the two lever elements 11, on which the
coupling rod
45 is pivotably mounted. The various axles are each accommodated in plain
bearings formed
by bearing bushes made of a polyoxymethylene copolymer (POM-C).
Figures 3A, 3B show a side view of the folding blade in the initial position
and in the retracted
position, respectively. The direction of travel points to the right. In the
initial position shown
in Figure 3A, both the front main surface of the base part 5 and the front
main surface of the
folding bar 6 lie in the extension of the clearing blade 2. They enclose an
angle of 450 with
the vertical. In the context of the present documents, this angle is defined
as "positive".
In the initial position, the hollow rubber spring 30 is in the maximum relaxed
position. It
pushes the deflection lever 40 obliquely downward, counterclockwise to its end
position,
which is defined by the stop 55 that interacts with the lever plates of the
deflection lever 40.
The stop 55 is adjustable by means of a set screw, so that the end position of
the lever
mechanism 10 and thus the end position of the folding bar 6 in the initial
position can be
adjusted. The coupling rod 45 acts on the lever element 11, which is firmly
connected to the
folding bar 6 (cf. also Figure 5E, where the corresponding linkage can be
seen), and pushes
it together with the folding bar 6 in the direction of travel. In the initial
position, the lever
element 11 is oriented practically horizontally, while the second element of
the elbow lever,
the pivoting arm 13 mounted on the base part 5, forms an angle of slightly
more than 90
with the lever element 11 and points practically vertically upwards.
In the retracted position shown in Figure 3B, the front main surface of the
folding bar 6
encloses an angle of -70 with the vertical. It is thus pivoted by 115 with
respect to the
Date recue/Date received 2023-05-08
13
initial position. Accordingly, the hollow rubber spring 30 is in a compressed
position and the
deflection lever 40 is pivoted clockwise with respect to the initial position.
The axis 12, which
forms the axis of rotation of the elbow lever, has moved upwards between the
initial position
and the retracted position together with the folding bar 6 and it is in
contact with the stop
51. The angle between the elements of the elbow lever, i.e. the lever element
11 and the
rotating arm 13, is again approximately 900
.
Figures 4A-4E illustrate the movement sequence of the folding blade when it
pivots back
after hitting an obstacle. The folding blade 1 typically contacts the obstacle
9 with the lower
end of the folding bar 6 (Figure 4A). As long as the obstacle 9 does not
exceed a certain
height, 30 mm in the example shown, it can be driven over without raising the
clearing blade:
The folding bar 6 folds back, and the obstacle 9 passes under the base part 5
of the folding
blade 1, which is firmly connected to the clearing blade 2. The folding back
is triggered by
the action of the obstacle 9, which initially causes the folding bar 6 to
pivot in a clockwise
direction (Figure 4B). This also causes the lever element 11, which is fixed
to the folding bar
6, to rotate clockwise around the axis 12. Due to the elbow lever, the
rotating arm 13 thereby
moves clockwise around the axis 14, which is fixed to the base part 5, so that
the axis of
rotation of the elbow lever, the axis 12, and thus the folding bar 6 are moved
upwards. This
superimposed movement takes place until the rotating arm 13 stops against the
corresponding stop 51 (Figure 40). Subsequently, a pure rotary movement takes
place
around the axis 12 of the elbow lever until a sufficient negative pivot angle
is reached that
the obstacle 9 can be passed (Figures 4D, 4E).
During pivoting-back, the lever element 11 acts on the hollow rubber spring 30
via the
coupling rod 45 and the deflection lever 40, compressing the spring.
Figs. 5A-5E show the movement sequence of the folding blade when it is
returned to the
initial position. The return movement takes place due to the spring force of
the compressed
hollow rubber spring 30. It starts as soon as the force of the obstacle is
removed. The hollow
rubber spring 30 acts on the deflection lever 40 via the spring guide rod 31
and moves it
counterclockwise. This results in a substantially linear compressive force of
the coupling rod
45 on the lever element 11, which is fixedly connected to the folding bar 6
(Figure 5A). Due
to the fact that the rotating arm 13 rests against the stop 51, this initially
results in a purely
Date recue/Date received 2023-05-08
14
rotational movement about the axis 12, so that the folding bar is pivoted in a
counterclockwise direction in the direction of the initial position. As soon
as the lever
element 11 contacts the stop 53 arranged on the base part 5 of the folding
blade 1 (Figure
5B), the elbow lever is also pivoted about the axis 14 via which the rotary
arm 13 is mounted
on the base part 5. This results in a superposition of the two pivoting
movements, controlled
by the downward sliding of the lever element 11 along the stop 53 (Figure 50).
In contrast to the pivoting back as described in connection with Fig. 4, an
intermediate
position is now reached (Fig. 5D), in which the folding bar 6 has already
largely assumed its
original pivoting position, but is still in a raised position, above the
ground. Finally, the folding
bar 6, further guided by the interaction between the lever element 11 and the
stop 53, is
moved downward in a practically linear movement until it reaches the initial
position (Fig.
SE).
The invention is not limited to the illustrated embodiment. In particular, the
folding blade
can have further movable and/or immovable elements. The geometry of the
levers, the
bearings and the spring element may be chosen differently. As described above,
in particular
the lever elements interacting with stops can have a specific outer contour in
order to
control or influence this interaction.
In summary, the invention creates a folding blade that provides improved
folding bar return
and thus better clearing results
Date recue/Date received 2023-05-08
15
Reference list
(not submitted)
1 Folding blade
2 Clearing blade
3 Blast wheel housing
Base part
6 Folding bar
6a Mounting plate
7 Bearing plate
8 Bearing plate
Lever mechanism
11 Lever element
11a, 11b Lever arm
11c Connecting plate
12 Axis
13 Rotary arm
13a Bearing tube
13b, 13c Lever arm
14 Axis
30 Hollow rubber spring
31 Spring guide rod
40 Deflection lever
40a, 40b Lever plate
41 Contact roller
42 Axis
Date recue/Date received 2023-05-08
16
45 Coupling rod
46 Axis
51 Stop
52 Stop
53 Stop
54 Stop
55 Stop
Date recue/Date received 2023-05-08
