Note: Descriptions are shown in the official language in which they were submitted.
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Title: SNOWPLOW WITH PIVOTING 5IAEHLAoES
(001] This invention relates to the provision of hinged sideblades
on snowplows, and to the manner zn which sideblades are mounted and
actuated for pivoting. Often, it is desired that the sideblades can be
rotated through 180 degrees, from full forward to full back, and to any
angle therebetween. It is a].mo desired that the left and right
sideblades can be rotated independently.
[0021 Traditionally, such sideblAdes have been actuated by
conventional linear hydraulic rams and associated levers. However, it
is difficult to provide a full 180 degrees of arcuate travel by means
of linear rams and levers. Some designers have resorted to double
ram/lever arrangemento, which are expensive and intricate,
[003] Instead of an arrangement of rams and levers, in the designs
as depicted herein a rotary actuator is employed for the purpose of
rotating the sideblade. A rotary actuator is a standard proprietary
item; in the typical hydraulic version, a rotary actuator contains a
hydraulic ram, which drives a piston having helical aplines. A
complementarily-qrooved rotor sleeve fits withira the piston, whereby
the sleeve rotates when the ram is pressurised. The machine component
to be rotated is bolted to the rotor sleeve.
[004] Rotary aotuators are sold for use in hydraulic equipment.
Typically, the rotary actuator includes a housing or casing that is
bolted to the fixed frame of the equipment. The component to be
rotated rotates with the rotor Bleeve about an axis defined by bearings
housed inside the aatuator unit, the axis of the bearings being
(usually) the same as the operational axis of the ram.
[0051 A rotary actuator -- as that expression is used herein --
should be contrasted with a motor. A motor is capable of spinning
continuously at so many revolutions per minute, whereas a rotary
actuator is capable only of a limited arcuate movement about its rotary
axis. The rotor sleeve of a rotary actuator (to which the component to
be rotated is attached) cannot move beyond that arc, i.e cannot spin
conta.nuous ly .
[006) A conventional rotary actuator hps it$ own bearings, inside
the h.ousing of the actuator. In the conventional applications of the
rotary actuator, it has been traditional to use the bearings already
provided in the rotary actuator as the only bearings needed to support
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the rotary component. This is fine, if the loading on the rotating
component is more or less a pure torque, without heavy jouxnal loading.
Thus, the use of rotary actuators, though not confined to pure-torque,
or almost pure-torque, applications (in which the journal or radial
loading is small), have been used therein. on the other hand, the
bearings inside the aotuator housing are (or could be) robust enough,
and design applications in which the bearings are called upon to
support substantial journal loading are not unknown.
[007] Typically, in a snowplow sideblade application, the
sideblade rotates about a vertical axis. The expression "vertical
axis" should be understood as including cases where the rotary axis is
actually at a measurable angle relative to the vertioal, but where the
rotary axis has a predominating vertical component.
[008] The sideblade, like any anowplow blade, is inevitably
subjected to occasional very large abusive impacts. These can occur
when the sideblade strikes a kerb, or a manhole-cover, etc. These
impacts do indeed transmit heavy journal loading into the (vertical)
sideblade bearings.
[009] It is recognised that such violent abusive loads occur often
enough that, if a hydraulic rotary actuator were subject.ed to the brunt
af the violence, the length of the service life of the rotary actuator
might not be satisfactory. It was an aim, in the deaigns as depicted
herein, to isolate and protect the rotary actuator from the violent
impacts that are inflicted upon the sideblade.
[0010] By way of further explanation, examples will now be
described with referenCe to the accompanying drawings, in whiche
Fig 1 is a (diagrammatic) plan view of a truck pushing a snowplow
assembly, with sideblades.
Fig 2 is a pictorxal view of the rear of the mainblade of a snowplow,
illustrating how sideblades are attached thereto.
Fig 3 is a view of the hinge area between the mainblade of Fig 2 and
the sideblade, when the sideblade is in line with the mainblade,
viewed from the rear of the snowplow.
Fig 4 is a sectional view of part of the hinge area shown in Fig 3.
Fig 5.is a cross-section of a rotary actuator.
Fig 6 is a diagrammatic p[an view of a snowplow assembly which incorporates a
safety
feature.
Fig 6a is a close-up of a portion of Fig.6.
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Fig.7 is the same view as Fig.6, but shows the components of the assembly In a
position of
possible danger.
Fig 8 is a detailed plctorlal view of the snowplow assembly of Fig.6.
[0011] The apparatuses shown in the accompanying drawings and
described herein are examples. The scope of the patent protection
sought is defined by the accompanying claims, and not necessarily by
specific features of the examples.
[0012] As shown in Fig 1, a truck 23 is pushing a snowplow unit 25
forwards, in the direction of the arrow. A mainblade 29 is angled so
that snow is being defleated off to the right side. As usual, the
truck driver actuates hydraulic rams 26 to set the deflection angle of
the main blade.
[0013] Sometimes, it is desired to increase the effective width of
a snowplow, especially rightwards, and a right sideblade 27 is shown
extending from the mainblade 29, in order to increase the width or
reach of the snowplow, in that direction.
[0014] Sometittles, also, it can be a problem that some snow might
spill off to the left of the mainblade 29. To inhibit this, in Fig 1 a
left sideblade 30 has been extended forwards. Both sideblades 27,30
are pivoted or hinged at the respective left and right ends of the
mainblade 29. The hinging structure permits the sideblades to have a
full one-eighty degrees range of arcuate movement relative to the
mainblade, from perpendicular leading the mainblade to perpendicular
trailing the mainbiade.
[0015] Other orientations of the left and right sideblades can be
required in other circumetances, and the sidablades 27,30 are rotatable
each through 180R, as indicated by the arcuate arrows, relative to the
mainblade 29. The orientations of the left and right sideblades are
controllable by the driver, using appropriate hydraulic flow control
valves (not shown). The valves control flow to the ports of right and
left rotary actuators, which are described below.
(0016] AS shown in Fig 2, the mainblade 29, as a unit, includes an
underblade 29U. An underblade is conventionally included in a
snowplow, in oase it should strike a road-object such as a manhole
cover, a kerb, an embedded lane-indicator, etc. The underblade 29U is
hinged, being mounted for pivoting movement about an axis 29A running
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left-right (i.e widthwise) across the mainblade 29, whereby the top
edge of the underblade 29U is hinged to the bottom edge of the curved
blade 29B. The underblade 29U is held in its normal working position
relative to the blade 29B by means of heavy springs. When an impact
happens, the springs allow the underblade 29U to pivot rearwards, thus
protecting the mainblade 29 from the full violence of the impact. As
mentioned, the provision of a hinged, sprung, underbiade is
conventional. The sidebladea 27,30 also have hinged, sprung,
underblades 27U,30U (described later), corresponding to the main
underblade 29U.
[0017] The right sideblade 27 can be considered to be at least
partially protected by its hinged, sprung, underblade, against violent
impacts due to road-objects striking that underblade. However, the
left sideblade 30 is not protected, or not so well-protected, by ita
hinged, sprung, underblade 30V, because an impaot would strike end-on
against the leading edge of that left unde=rblade. It is impacts like
that that can cause the bearings in a rotary actuator to deteriorate,
if those impacts were felt by the actuator.
[0018] The violent impact is felt mainly by the bottom regions of
the sideblade hinge atructure. In the designs depicted herein, the
vertical axis 32 about which the sideblade pivots is defined by two
spaced bearings, i.e an upper hinge bearing 43 and a low r hinge
bearing 45. The lower hinge bearing 45 ia the subject of Fig 4. The
upper hinge bearing 43 is the bearing inside the rotary actuator 47,
the subject of Fig 5.
[0019] The lower hinge bearing 45 includes a main hinge leaf 45M,
attached to the main blade 29B, and a side hinge leaf 45s, attached to
the left side blade 308. A hinge-pin 49 connects the two hinge leaves.
[0020] The main leaf 45M of the lower hinge 45 includes a main
bracket 50. The main bracket 50 ia welded to an endplate 52 of the
mainblade 29. The bracket 50 is also welded to a bol$ter 54, which
runs the width of the mainbiade (and on which are mounted the bearings
that define the pivot axis 29A). The main bracket 50 carries upper and
lower cylindrical tubes 56,57, into which have been pressed cylindrical
bearing-rings 58,59. The bearing-rings are a running fit over the
hinge-pin 49.
[0021] The side leaf 455 of the lower hinge includes a side bracket
60. The side bracket 60 is welded to the blade 30B of the left
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sideblade 30. The side bracket 60 is also welded to a reinforcing
strut 63 of the blade 30B. The side bracket 60 carries upper and lower
cylindrical tubes 64,65, into which have been pressed cylindrical
bearing-ringe 67,68. Again, these bearing-rings are a running fit over
the hinge-pin 49. The bearing rings 58,59,67,68 are of suitable
bearing material, preferably a metal such as a bronze-based bearing
metal, although a plastic material such as (filled) PTFE may be
considered.
[0022] Collars 70 are clamped to the hinge-pin 49, and serve to
locate the hinge-pin 49 in a vertical sense in the lower hinge 45.
[0023] The function of the main bracket 50 is to ensure that the
bearing-rings 58,59 are functionally unitary with the main blade 29B.
The designer should see to it that the cylindrical tubes 56,57 are
supported solidly and rigidly with respect to the blade 29B, and ehould
provide such brackets, struts, reinforcements, etc, as are zequired to
ensure that this is so. The extent to which the tubes and the blade
should be solid and rigid with respect to each other is such that the
tubes and blade remain mutually solid and rigid, even when subjected to
the largest abunive forces that the snowplow as a whole is designed to
encounter. The same applies to the solidity and rigidity with which
the cylindrical tubes 64,65 are supported with respect to the side
blade 29B,
[0024] The main bracket 50 carries two spaced tubes 56,57, and the
side bracket 60 carries two apaced tubes 64,65. These four tubes are
arranged geometrically so as to intercalate, one above another, as
shown. This arrangement gives the best support for the pin 49, and for
the lower hinge 45 as a whole. The bending stresses on the pin would
be higher if only one tube per leaf were provided, or if one leaf had
two tubes and the other leaf had only one. The higher the bending
stresses on the hinge-pin, the thicker the hinge-pin would have to be,
and the more robust the supporting tubes and brackets would hava to be.
More than two cylindrical tubes per leaf of the hinge would be
incrementally better still, from the stress standpoint, but the
increment would be amall.
[0025] The upper hinge bearing 43 comprises the bearings inside the
rotary actuator 47. The presence of the lower hinge 45 is a preferred
feature of the designs as depicted herein, in that the presence of the
highly-robust lower hinge 45 means that the bearings inside the rotary
actuator 47 are protected from the violent impacts and abusive loads
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that the snowplow will inevitably encounter.
[0026J it is also preferred that the rotary actuator 47 be provided
as the upper hinge, not the lower hinge. If the rotary actuator were
to form the lower hinge, the bearings in the rotary actuator would not
be isolated and protected nearly so effectively from the violent
impacts against the bottom regions of the sideblade.
[0027] The hQusing of the rotary actuator is bolted to the endplate
52 0f the mainblade 29, using the prepared bolt-holes 72 as shown in
Fig 2. The designer should arrange for appropriate struts, gussets,
and other reinforcing provisions, as required. In Fig.2, it can be
seen that the major stiffening and reinforcing Btructures are provided
in respect of the lower hinge 45, rather than in respeet of the rotary
actuator / upper hinge 43; again, this is in keeping with the fact that
it is the lower hinge 45 that suffers the brunt of the violent impacts.
[0028] In Fig.3, a top strip 74 of the sideblade 27 is bolted, at
76, to the rotor sleeve 78 of the rotary actuator 47. A bottom strip
80 is part of the structure of the sideblade 27, and ig clamped also to
the rotor sleeve 78. A longbolt 83 passes lengthwise through the
hollow interior of the rotor sleeve 78, clamping the bottom strip 80
also to the rotoz sleeve 78.
[0029] The structure and operation of the rotary aCtuator 47 will
now be described with reference to Fig 5. A rotary actuator is a
proprietary item, and designs other than the example now described may
be employed. It is preferred that the actuator be of a design in which
the rotor sleeve 78, to whiGh the item to be rotated is bolted, should
swivel in a single-plane circle, the plane of the circle being
perpendicular to the axis of rotation of the actuator. This prQferenoe
is followed in the design as shown In Fig.5. It would not be preferred
if the actuator were of a design in which the rotor sleeve follows e.g
a helical path.
[0030] The actuator includes a hydraulic piston 85, which
reciprocates in a cylinder 87. On the left of Fig 5, the piston is
shown in its uppermost position, and is shown on the right in its
lowermost position. Ports 89,90 (Fig 3) transfor hydraulic fluid into
and out of the cylinder 87, above and below the piston 85. Attached to
the piston 85 is a skirt 92. The skirt. 92 is formed with internal 94
and external 96 helical splines. The helical splines may be regarded
equala,y as a multi-start screw thread, having a steep helical lead
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angle. When the piston 85 moves downwards, the engagement of the male
splines 96 with the corresponding female splznes 98 in the actuator
housing 100 causes the piston to rotate. Thus, the piSton 85, with its
skirt 92, undergoes a helical movement, i.e undergoes rotation with a
simultaneous axial movement.
[0031] The internal female splines 94 on the skirt 92 engage the
male splines 103 on the rotor sleeve 78. The internal and external
splines 94,96 are of opposite hand, whereby the sleeve 78 rotates
through an overall angle of arc that is determined by the sum of the
respective helical lead anglee of the two splines. The rotor sleeve 78
cannot move axially with respect to the housing 100, being confined
between thrust bearings 105,106. The rotor sleeve 78 is guided for
rotation in the housing 100 in journal bearings 108,109. Thus, the
structure of the hydraulic rotary actuator 47 is such that the sleeve
78 rotates in a single-plane circle when relatively prassurised
hydraulic fluid is applied to one of the ports 89,90,
[0032] As shown in Fig 4, the bearing rings 58,59,67,68 are
arranged to perform thrust duties, in addition to their journal duties.
However, this requires careful vertical alignment of the rings in
relation to the rotary actuator -- which also includes thrust bearings
-- and the designer might prefer to arrange the bearing rings no that
they cannot touch each other in the thrust sense, whereby all the
thrust loading falls on the bearings 105,106 in the hydraulic rotary
actuator 47. (The abusive impaCt shocks that a snowplow blade
encounters generally have only a small thrust component.)
[0033] The extent of the arcuate travel of the rotor sleeve 78 is
determined by the geometry of the actuator. In the particular example,
the axial lenqth of travel of the piston 85, and the lead angles of the
two helical splines, is such that the rotor sleeve is designed to
undergo a maximum arcuate travel of 1802, as the piston is driven from
top to bottom of its available travel within the cylinder 87.
[0034] It will be understood that the bearings 105,106,108,109 in
the rotary actuator are not intended or designed to cope with violent
abusive loadings. The bearings can be plain, as shown, and of nylon,
bronze, etc, as required. The bearings 105,106,108,109 are designed to
cope with the axial and radial loads that are applied to the bearings
as a result of the torque that is generated in the sleeve due to the
applied hydraulic pressure. Of course, the prudent designer of the
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actuator provides a margin of tolerance, by which the bearing capacity
is sufficient to provide a long service life, but it is recognised that
the kind and size of the bearings normally encvuntered in a hydraulic
rotary actuator, by themselves, fall well short of the robustness
needed to support a hinging eideblade of a anowplow.
[0035) The radially-projected bearing area of the journal bearings
108,109 in the rotary actuator Ji.e in the upper hinge 43) may be
compared with the radially-projected bearing area of the bearing rings
67,68 in the lower hinge 45. It is appar8nt, from the difference in
size, that the load capacity of the lower hinge is an order of
magnitude greater than the load capacity of the bearings 108,109 in the
actuator. It might be possible for a rotary actuator to be designed in
which the load capacity of the journal bearings was the equal of the
load capacity of the lower hinge 45; however, it can easily be seen how
such an increased load capacity would enta,iJ, some very radical changes
to the structure (and to the cost) of the rotary actuator. Providing a
lower hinge 45 of hugely increased load capacity, as compared with the
actuator, means that the standard conventional rotary actuators can be
used in the snowplow blade application as described herein, without
modification and without damage.
[0036] Because of the new arrangement as described herein, only the
lower hinge 45 suffers the effects of the impacts on the snowplow
sideblade. The relatively puny bearings 108,109 in the rotary actuator
47 are substantially protected from impacts by the provision of the
relatively huge bearings in the lower hinge 45. It is a simple matter
to design the bearings of the lower hinge to be robust enough to take
the heavy impacts. Thus it is recognised that, in the snowplow
application, it would be much less preferred to provide just the rotary
actuator as the sole hinge bearing, with no supplementary hinge
bearing.
[0037] It will be recognised from the drawings that pXOviding the
hinge bearings with the high degree of robustness as described is
achieved without resorting to hydraulic rams and linkages. The rotary
actuator has a neat, compact form, and is much less likely to be
damaged, in the abusive snowplow environment, than an equivalent rams-
and-linkage type of rotation-producing mechanism. Also, the rotary
actuator being fixed to the mainblade, the hydraulic hose and lines to
the rotary actuator do not move, relative to the mainblade, during
operation -- which means that flexible hoses -- which are expensive and
vulnerable to damage -- can be reduced or even eliminated.
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[0036] The proprietary rotary aotuatoz, though an expensive item in
itself, actually can work out oheaper, in overall money terms, than the
equivalent linear ram(s) and associated linkage. Also, the rotary
actuator is small and neat -- being hugely different, in that respect,
from the ram-and-linkage equivalent.
[0039] As shown, preferably the snowplow includes both left and
right sidebladea, of which both can pivot through 1801. However, the
rotary actuator can be used in the manner deacribed herein in a
snowplow that has only one s,iideblade.
[0040] The paracular rotary actuators shown in Fig 1 have a range of 780 . As
far as the
rotary actuators 47 are concemed, the sideblades can lie at 90 to the
mainblade, either
forwards or rearwards, or anywhere between, as shown in Fig 1.
10041] It s recognised that the following dangerous condition might arise. If
the mainblade 29
is pivoted clockwise relative to the frame, and the sideblade 27 is pivoted
clockwise relative to
the mainblade 29, possibly the sideblade 27 might strike the wheel or tire of
the vehicle. That
is to say: If the two pivoting movements were allowed to go, together, to
their full clockwise
limits, the right sidebiade would strike the right wheel. (The same condition
might arise In
respect of the left side wheel, but that is less likely, in practice.)
[00421 In Fig 6, the mainblade 29 Is In the flat or straight-ahead position,
and it can be seen
that the sideblades 27,30 can now be allowed their full range of pivoting
movement, without
any danger of their striking the wheels. But in Fig 7, the combination of the
two pivoting
movements has almost reached the danger condition, whereby further clockwise
pivoting
might be dangerous.
[0043] To alleviate this possible danger, a wheel-protection link 120 has been
incorporated
into the design. The function of the wheel-protection link 120 is to block any
further movement
of the sidebiade 27 towards the wheel 121. Similarly, the left side wheel-
protection link 134
protects the left wheel from being contacted by the left side-blade 30.
[0044] The wheel-protection link 120 incorporates a sliding lost-motlon
connection 122, in
which a rod 123 slides In a sleeve 125 of the link. The end 129 of the rod
forms an
abutment, and the deep end 130 of the sleeve forms a stop. If the abutment 129
were to
strike the stop 130, further movement of the sidebtade 27 in the clockwise
direction would then
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be blocked.
[0045] In Fig.7, the abutment 129 has almost reached the stop 130. If the
operator were now
to attempt to move either the mainblade or the sideblade further, in the
clockwise direction, the
abutment would bottom out - thus blocking that further movement.
[0048] It will be understood that further clockwise movement of the mainblade
29, from the
condition shown in Fig.7, is permitted; but if such further ciockwise pivoting
of the mainblade
were to take place, the bottoming out of the wheel-protection link 120 would
not just block the
sideblade 27, but would cause the sideblade 27 then actually to rotate counter-
clockwise
relative to the mainblade 29, so as not to approach any closer to the wheel.
[0047] Fig.8 shows a more detailed view of the mainblade 29, now lying
straight (i.e parallel
to the width of the vehicle), and the right side-blade 27 lies angled
backwards (towards the
vehicle) at 90 to the main-blade. The apparatus in Fig.8 includes the left-
side wheel-
protection link 134, and the right-side wheel-protection link 120.
[0048] The mainblade 29 pivots relative to the vehicle on its main pivot, at
136, located on the
frame 132, which Is solidly attached to the vehicle. The wheel-protection link
120 Is pivoted,
at link-frame pivot 138, to the frame. The link-frame pivot 138 is located a
distance D to the
rear of the mainblade-frame pivot 136. The other end of the wheel-protection
link is pivoted,
at 140, to an arm 141, which is solid with the side-blade 27.
[0049] The effect of this configuration is that, as the maln-blade 29 angles
clockwise, the
wheel-protection link 120, as a whole, follows that clockwise movement. As a
result of the
spacing D of the two pivots 136,138, the link-sideblade pivot 140 moves to the
right, relative to
the mainblade, as the main-blade rotates clockwise about the mainblade-frame
pivot 136.
[0050] As described, the angle of the side-blade 27 relative to the main-blade
29 is controlled
by the hydraulic rotary actuator 47. Incorporated into the hydraulic circuit
associated with the
actuator 47 is a pressure-sensing cross-over valve. This (conventional) valve
has the ability to
allow fluid to pass from the upper chamber 145 of the actuator 47 into the
lower chamber 147,
or vice versa, when the pressure between the two chambers exceeds a pre-
determined
maximum. If the side-blade 27 should start to approach too closely to the
wheel 121, and the
lost-motion connection 122 bottoms out, the force transmitted through the
wheel-protection link
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120 to the side-blade 27 does give rise to such a pressure differential
between the two
chambers. Therefore, the side-blade 27 can and does rotate away from the wheel
121.
[0051] The pressure-sensing crossover-valve +s providad In any case, in the
system, to allow
the sideblade 27 to break back from the mainbiade 29 without incurring damage -
if the
sidebiade 27 should strike a kerb, for example.
[0052] It might, of course, be possible to trust the driver of the vehicle to
control the angles of
the mainblade 29 and of the sideblade 27 so carefully and competently that the
sideblade 27
never would touch the wheel 121 _ On the other hand, without the wheel-
protection link 120, it
would always be possible for the driver to touch the side-blade against the
wheel accidentally,
perhaps due to the driver momentarily not paying attention, or lacking the
proper skill, etc.
The presence of the wheel-protection links 120,134 makes it impossible for the
driver to move
the blades to a position where touching the wheel might arise.
[0053] The wheel-protection link 120, when bottomed out, forms a solid rod,
between the link-
frame pivot 138 and the link-sideblade pivot 140, when the blades 29,27 are
in, or are
approaching, the danger position. In order to allow free rotation of the side-
blade 27 at other
orientations of the blades, when the danger of touching the wheels is not
present, the wheel-
protection link 120 has to be capable of being elongated. The lost motion
connection 122
provides this facility. The link 120 can be elongated by the rod 123 sliding
out of the sleeve
125. In the Fig.8 unit, a peg 148 (Fig.BA) that is solid with the rod 123 runs
in a slot 149
formed in the sleeve 125. When the wheef-protectian fink 120 needs to
elongate, the peg 148
of the rod 123 can slide in the slot 149 of the sleeve 125.
[0054] If the designer designs the wheel-protection link to be suitable for a
particular size and
configuration of snowplow, It Is likely that the wheel-protection link will
protect the wheels of
every type of vehicle upon which that size and type of snowplow can be used_
However, the
wheel-protection link could be made adjustable, In the hands of the operator,
to meet special
situations. Thus, in the adjustable version, the peg 147 could be made to be
adjustable as to
its position along the length of the rod 123.
[0055] The wheel-protection link, as shown, might, in some cases, be
drff'icult to
accommodate in what is a premium space, between the mainbiade and the vehicle;
and of
course there is the expense of the Ifnk itself. Alternatively, blocking the
sideblade from
approaching too closely to the tire can be done by other means. For example,
sensors may
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12
be included, which signal the extensions of the mainblade rams 26, and the
positions of the
rotary actuators 47. From these signals, a simple sum of the angles indicates
the approach of
the danger condition, This Indication can be used to trigger a hydraulic
blocking valve, which
prevents further movement of the rotary actuator in the direction of
increasing danger.
(0056] The designer must of course see to It that the point at which the
sideblade is blocked
from moving closer towards the wheel is appropriate to the situation_ This may
be done
geometrically, by laying out in a drawing, or by calculating, the positions of
the pivots and the
distances between them, such that the movements thereof block the sidebtade
appropriately.
[0057] Preferably, the geometrical layout should include the feature that the
link-frame pivot
138 Iles closer to the vehicle than does the mainblade pivot 136, and that the
link-sideblade
pivot 140 Iles closer to the vehicle than does the sideblade pivot axis 32.
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Reference wumerals
23 truck
25 snowplow unit
27 right sideblade ( unit )
27U underblade foX . .
29 mainblade (unit)
29U underblade of 29
29B blade of 29
29A pivoting axis of 29t7 (horizontal)
30 left sideblade
32 hinge axie of 30
43 upper hinge bearing
45 lower hinge beering
45H main hinge leaf
45S side hinge leaf
47 rotary actuator
49 hinge pin
50 main braoket of main leaf 45M
52 endplate of mainbla.de
54 bolster at foot of mainblade
56 upper cylindrical tube of main leaf
57 lower cylindrical tube of main leaf
58 upper bearing ring in 56
59 lower bearing ring in 57
60 side bracket of side leaf 45S
63 reinforcing strut in sideblade 27
64 upper cylindrical tube of side leaf
65 lower cylindrical tube of side leaf
67 upper bearing ring in 64
68 lower bearing ring in 65
70 collars
72 bolt-holes in endplate 52 for 47
74 top strip of sideblade
76 ring of bolts to
78 rotor sleeve
80 bottom strip
83 longbolt
85 piston
87 cylinder
89 upper hydr port
90 lower hydr port
92 skirt
94 internal splines on skirt
96 external splines on skirt
98 female splines in
100 actuator housing
103 male epl.znes on rotor sleeve 78
105 upper thrust bearing
106 lower thzust bearing
108 upper journal bearing
109 lower journal bearing
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120 wheel-protection link
121 link
122 sliding lost-motlon connection
123 rod
125 sleeve
129 end of rod = abutment
130 deep end of sleeve = stop
132 flxed frame of snowplow unit
134 wheel-protection link (left side)
136 maioblade pivot
138 link-frame pivot
140 link-sideblade pivot
141 arm of slideblade
145 upper chamber of rotary actuator
147 lower chamber of rotary actuator
148 peg
149 slot
