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BACKGROUND OF THE INVENTION
1. Field Of The Invention
The present invention relates generally to blender apparatus, and more
particularly to a blender apparatus including an automatic level control
device.
2. Description Of The Prior Art
Many activities conducted in connection with the servicing of oil or gas
wells involve the blending of one or more solid particulate materials with
a liquid which is to be pumped down into a well.
A relatively recent development by the assignee of the present invention is
the constant level additive mixing system disclosed in U.S. Pat. No.
4,490,047 to Stegemoeller et al. The Stegemoeller et al., U.S. Pat. No.
4,490,047 system provides a blender tub which is resiliently supported
from a base by a torsion bar extending through the tub. As the fluid level
in the tub changes the tub resiliently moves relative to the base. This
movement is transmitted to a control valve which then responds by
directing more or less fluid to the blender tub, thus controlling the
fluid level within the tub.
The purpose of this system provided in the Stegemoeller et al., U.S. Pat.
No. 4,490,047 is to provide a blender typically of relatively low capacity
which does not need to be constantly monitored by a human operator.
One particular problem encountered with the system of the Stegemoeller et
al., U.S. Pat. No. 4,490,047 involves the placement of the torsion bar.
The torsion bar utilized to suspend the blender tub in the U.S. Pat. No.
4,490,047 extends through the body of the blender tub itself thus
interfering with the flow of fluid in the blender tub and preventing the
use of some forms of mechanical agitation which would extend down to the
bottom of the blender tub. This arrangement utilized a mixing tub having a
shape that was not ideal for many mechanical mixers. Also the placement of
the torsion bar prevented the effective use of mechanical mixers.
SUMMARY OF THE INVENTION
The present invention provides an improved shape for a blender tub as
compared to the Stegemoeller et al., U.S. Pat. No. 4,490,047 device. This
shape has been made possible by relocating the supporting torsion bar so
that it no longer extends through the tub. The blender tub is now shaped
in a generally downward tapered, preferably conical configuration.
This is very compatible with the use of a rotating mechanical mixing means
disposed in the tub.
The rotating mechanical mixing means induces and aids a vortex-type flow in
the generally tapered, conically shaped tub. It also aids in the expulsion
of that material out a tangential outlet in the bottom of the blender tub.
The mechanical agitator preferably includes a top rotating agitator, and a
reversing helical screw flight located below the top agitator for breaking
up the vortex immediately adjacent a rotating shaft of the agitator and
for causing fluid to flow upwards in that vicinity. The mechanical
agitator preferably also includes a bottom rotating agitator means located
near the bottom of the blender tub for sweeping the bottom of the blender
tub and again directing particulate material out the tangential outlet of
the blender tub.
Numerous objects, features and advantages of the present invention will be
readily apparent to those skilled in the art upon a reading of the
following disclosure when taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a truck-mounted blender system with associated
power source, liquid additive storage, work station, and lifting
apparatus.
FIG. 2 is an elevation view of the apparatus of FIG. 1.
FIG. 3 is a plan view of the mounting rack for the liquid additive tanks.
FIG. 4 is a side elevation view of the mounting rack of FIG. 3.
FIG. 5 is an end elevation view of the mounting rack of FIG. 3.
FIG. 6 is an enlarged sectioned view taken along line 6--6 of FIG. 3
showing the details of the connecting pin and retainer pin as assembled
with the mounting rack and a container.
FIG. 7 is a right end view of the structure of FIG. 6, with the container
not shown in this view.
FIG. 8 is a plan view of the lifting apparatus mounted on a truck bed
showing the apparatus in the DOWN position.
FIG. 9 is a side elevation view of the lifting apparatus of FIG. 8 showing
the apparatus in the UP position.
FIG. 10 is a side elevation view similar to FIG. 9 but showing the lifting
apparatus in the DOWN position.
FIG. 11 is a plan view similar to FIG. 8 showing the latch assembly for
locking the lifting apparatus in its UP position.
FIG. 12 is a schematic flow diagram of the blender system.
FIG. 13 is a schematic flow diagram similar to FIG. 12, showing the
addition of a concentrator downstream of the low pressure pump.
FIG. 14 is a rear elevation view of the blender assembly of FIG. 1, which
has been modified by the addition of a concentrator downstream of the low
pressure pump. The blender assembly of FIG. 14 utilizes a steel blender
tub. It is noted that this rear elevation view is taken as it would be
seen standing behind the rear of the truck 10 and looking toward the
blender apparatus 38.
FIG. 15 is a right end elevation view of the apparatus of FIG. 14.
FIG. 16 is a plan view of the apparatus of FIG. 14.
FIG. 17 is a left end elevation view of the apparatus of FIG. 14.
FIG. 18 is an enlarged view of the blender tub showing in dashed lines the
location of a mechanical agitator located therein.
FIG. 19 is a plan view of the top rotating agitator means of the mechanical
agitator.
FIG. 20 is an elevation view of the top rotating agitator means of FIG. 19.
FIG. 21 is a plan view of a bottom rotating agitator means of the
mechanical agitator.
FIG. 22 is an elevation view of the bottom rotating agitator means of FIG.
21.
FIG. 23 is a plan view of a steel blender tub.
FIG. 24 is a rear elevation view of a steel blender tub.
FIG. 25 is a right end elevation view of the blender tub of FIG. 24.
FIG. 26 is an enlarged sectioned view of the upper perimeter of the blender
tub of FIG. 24.
FIG. 27 is a plan view of an non-metallic blender tub liner of the type
utilized with a tub support framework.
FIG. 28 is a rear elevation view of the tub liner of FIG. 27.
FIG. 29 is a right end elevation view of the tub liner of FIG. 28.
FIG. 30 is a plan view of an alternative embodiment of the blender
assembly, wherein the tub and its self-leveling control apparatus are
contained on a skid which does not contain a pump. Connections are
provided for connecting the blender tub of FIG. 30 to an external pump.
The blender tub of FIG. 30 utilizes a non-metallic liner contained within
a supporting framework.
FIG. 31 is a rear elevation view of the apparatus of FIG. 30.
FIG. 32 is a left end elevation view of the apparatus of FIG. 31.
FIG. 33 is a right end elevation view of the apparatus of FIG. 31.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
General Description Of The Layout Of The Vehicle
Turning now to the drawings, and particularly to FIGS. 1 and 2, a blender
vehicle apparatus is thereshown and generally designated by the numeral
10. In the particular embodiment shown, the vehicle 10 is a motor truck
having a vehicle frame 12 with a driver's cab 14 mounted thereon.
Behind the cab 14 there is located an internal combustion engine driven
hydraulic power package generally designated by the numeral 16. The power
package 16 includes an internal combustion engine 18 which drives three
hydraulic power pumps 20, 22 and 24 which provide hydraulic power fluid to
the various other systems located upon the frame 12 of the vehicle 10.
The various systems mounted on the vehicle 10 have a power requirement
which can be supplied by only two of the three hydraulic power pumps 20,
22 and 24, thus providing a safety feature in that if one of the pumps 20,
22 and 24 fails, there will he sufficient hydraulic power provided by the
two remaining pumps to complete a well service job which is under way.
Adjacent and to the rear of the power package 16, a plurality of liquid
additive storage tanks 26, 28, 30 and 32 are mounted upon the frame 12.
An operator's work platform 34, which includes a control station 36 is
mounted on the vehicle frame 12 to the rear of and adjacent the storage
tanks 26-32.
To the rear of the work platform 34 there is located a hydraulically
powered blender assembly generally designated by the numeral 38.
A hydraulically powered lifting means generally designated by the numeral
40, is mounted on the vehicle frame 12 for moving the blender assembly 38
between a lowered or DOWN position as illustrated in FIGS. 1, 8 and 10 and
a raised position as illustrated in FIGS. 2 and 9. The raised position of
blender assembly 38, as seen in FIGS. 2 and 9, has the blender assembly 38
located above the vehicle frame 12 and relatively closely adjacent the
work platform 34 on the side thereof opposite the storage tanks 26-32.
The lifting means 40 is further characterized in that when the blender
assembly 38 is in its raised position as shown in FIG. 2, the blender
assembly 38 is located at least in part directly above the vehicle frame
12. When the lifting means 40 moves the blender assembly 38 from its
raised position to its lowered position as seen in FIGS. 1 and 10, the
blender assembly 38 is moved in a generally horizontal direction rearward
away from the work platform 34 and then is moved downward to an elevation
as seen in FIG. 10 which is lower than the vehicle frame 12.
The importance of this is that regulations for loads pulled on the public
highways prevent the extension of a load more than two feet behind the end
of the vehicle frame. The construction of lifting means 40 allows
compliance with such regulations while at the same time providing a means
for easily moving the load to the rear of the vehicle frame 12 and then
downward to a ground level position.
A fold-up walkway means generally designated by the numeral 42 includes a
walkway 44 having one end thereof pivotally mounted at 46 adjacent the
work platform 34. The walkway 44 extends generally horizontally from the
work platform 34 to the blender assembly 38 when the blender assembly 38
is in its lowered position as is best in FIG. 1.
The fold-up walkway means 42 includes a walkway linkage 48, best seen in
FIG. 2, constructed to swing the walkway 44 up towards the work platform
34 when the blender assembly 38 is moved from its said lowered position to
its said raised position as illustrated in FIG. 2.
The details of the blender assembly 38 are best shown in FIGS. 14-17. It is
noted that the blender assembly shown in FIGS. 14-18 is slightly modified
as compared to that shown in FIGS. 1 and 2, in that a concentrator means
48 has been added to the blender assembly. To designate this modification,
the blender assembly of FIGS. 14-17 is designated by the numeral 38A.
Aside from the differences associated with the addition of the
concentrator means 48, however, the blender assembly 38A is generally the
same as and is representative of the blender assembly 38 of FIGS. 1 and 2.
In the following description any reference to blender assembly 38 or
blender assembly 38A may be taken as referring to either unless the
context of the reference deals with the concentrator 48 or associated
apparatus which are found only on the embodiment 38A.
Turning attention now to the general arrangement of the apparatus contained
in the blender assembly 38, with particular reference to FIG. 14, the
blender assembly includes a blender assembly base 50. A blender tub 52 is
supported from the base 50 by first and second spaced parallel support
arms 54 and 56. In a manner further described below, the support arms 54
and 56 are pivotally connected to the base 50, and the blender tub 52 is
pivotally suspended from the support arms 54 and 56.
The blender assembly base 50 may also be generally described as a blender
pallet base 50 having a pair of fork openings 53 and 55 defined therein.
The lifting means 40 includes a load fork 57 having a pair of tines 59 and
61 which are received in the fork openings 53 and 55 of pallet base 50.
The blender assembly 38 further includes one and only one blender pump
means 58, supported from the base 50, for drawing base fluid or "clean"
fluid through a fluid supply conduit 304, 306 from a fluid supply (not
shown) and for drawing blended fluid from the blender tub 52. The pump
means 58 recirculates a portion of the combined base fluid and blended
fluid back to the blender tub 52, and discharges another portion of the
combined base fluid and blended fluid away from the blender assembly 38.
The base fluid is often referred to as "clean" fluid, but it should be
noted that the base fluid is often clean only in the sense that it has not
yet been blended with sand. This "clean" base fluid may in fact be very
muddy, oily or the like.
An automatic level control means generally designated by the numeral 62 is
operably associated with the blender tub 52 and the blender pump means 58
for controlling a fluid level within the blender tub 52.
The lifting means 40 which moves the blender assembly 38 between its upper
and lower positions can be further characterized as a means for placing
the blender assembly 38 at ground level as illustrated in FIG. 10 to
thereby minimize an elevation of a suction inlet 64 of blender pump means
58. All of this operation is further described in considerable detail
below.
One important reason, however, for providing the lifting means 40 whereby
the blender assembly 38 can be lowered to ground level, is that the
blender assembly 38 uses one and only one pump means 58 for both drawing
base fluid from a fluid supply and for drawing blended fluid including
sand or the like from the blender tub 52, and then discharging the
combined materials to a point of usage such as a high pressure pump for
injecting the material into an oil well, and for also recirculating a
portion of the fluid back to the blender tub 52. Since one and only one
pump is utilized to accomplish all of these duties, its performance is
sometimes limited by its ability to draw base liquid from whatever liquid
supply is available, particularly if that liquid supply is at a relatively
low elevation. This drawback of such a single pump system is to a
significant extent alleviated by the placement of the blender assembly 38
at ground level, rather than having it remain on the vehicle frame 12.
This provides several additional feet of suction head to the suction inlet
64 of the pump means 58.
It is further noted that the lifting means 40 may place the blender
assembly 38 at an elevation somewhat lower than the ground elevation on
which the truck 10 rests. That is, the blender assembly 38 may actually be
lowered into a relatively shallow depression.
It is also noted that it is much easier to add dry additives such as sand
when the blender apparatus 38 is sitting at ground level.
As seen in FIGS. 14 and 16, the blender assembly 38 includes a dry or
particulate materials hopper generally designated by the numeral 66
located above the blender tub 52 and having an adjustable lower outlet 68
for controlling a flow of dry materials such as sand into the blender tub
52. The adjustable outlet 68 has a sliding gate 70 (see FIG. 16)
controlled by a hydraulic ram 72 (see FIG. 14) for controlling the size of
the opening of the adjustable outlet 68.
Also, the dry materials may sometimes be introduced into tub 52 through an
eductor 67 (see FIG. 1). The eductor 67 directs the dry material through a
central opening, while directing a recirculating stream 320 (see FIG. 12)
through an annular opening surrounding the central opening so as to
impinge the recirculating stream 320 upon the incoming dry materials to
thoroughly wet them.
Liquid Additive Tanks And Mounting Rack
Referring to FIGS. 1 and 2, the liquid additive storage tanks 26, 28, 30
and 32 are mounted upon a mounting rack 74 which is supported from the
vehicle frame 12.
The mounting rack 74 is shown in detail in FIGS. 3, 4 and 5. FIG. 3 is a
plan view of the mounting rack 54, the length of which lies crossways
across the width of vehicle frame 12.
The right end view of mounting rack 74 as seen in FIG. 2 is the same as and
corresponds to the right end view of mounting rack 74 shown in enlarged
view in FIG. 5.
The mounting rack 74 has two full-size tank base locations defined thereon.
One of those full-size tank base locations has been outlined in phantom
lines and designated by the numeral 76 in FIG. 3.
The mounting rack 74 has eight mounting means 78-92 for mounting either one
full-size tank base, two half-size tank bases, four quarter-size tank
bases, or one-half size and two quarter-size tank bases, within the
full-size tank base location 76. Four of the mounting means 78, 80, 82 and
84 are located along a front side of the full-size tank base location 76,
and the other four mounting means 86, 88, 90 and 92 are located along the
opposite rear side of the full-size tank base location 76.
As is apparent in FIG. 3, the full-size tank base location 76 is generally
rectangular in shape. The eight mounting means 78-92 include four corner
mounting means 78, 84, 86 and 92 located generally in the four corners of
the generally rectangular-shaped full-size tank base location 76. Also
included are four intermediate mounting means 80, 82, 88 and 90.
A full-size tank such as tank 26 is mounted in the full-size tank base
location 76 as follows. The full-size tank 76 includes four angular-shaped
legs 94, 96, 98 and 100. When the full-size tank 26 is set in place within
the full-size tank base location 76 as shown in FIG. 1, the four legs 94,
96, 98 and 100 will then be releasably connected, in a manner described
below, to the corner mounting means 86, 78, 84 and 92, respectively.
Two half-size tanks such as tank 28 would be located within the full-size
tank base location 76 as follows.
The half-size tank 28 includes four right-angle shaped legs 102, 104, 106
and 108. A first half-size tank 28 would be located on the left-hand side
of the full-size tank base location 76 by releasably connecting its legs
102, 104, 106 and 108 with mounting means 86, 78, 80 and 88, respectively.
A second half-size tank 28 would be located on the right-hand side of
full-size tank base location 76 with its legs 102, 104, 106 and 108
releasably connected to mounting means 90, 82, 84 and 92, respectively.
One half-size tank 28 and two quarter-size tanks such as 30 and 32 can be
mounted in the full-size tank base location 76 in a manner like the
arrangement of tanks 28, 30 and 32 illustrated in FIG. 1. The half-size
tank 28 would be mounted as previously described and connected to mounting
means 86, 78, 80 and 88.
The two quarter-size tanks 30 and 32 would be mounted as follows. The
quarter-size tank 30 has a quarter-size tank base including four legs 110,
112, 114 and 116. Similarly, quarter-size tank 32 has legs 118, 120, 122
and 124.
The legs 112 and 114 of tank 30 are fixedly connected to the legs 118 and
124, respectively, of the tank 32 such as by bolting the same together
with a spacer (not shown) sandwiched therebetween, so that the
bolted-together quarter-size tanks 30 and 32 occupy the same space as a
single half-size tank 28.
Then this bolted-together combination of two quarter-size tanks 30 and 32
could be mounted within the right-hand side of full-size tank base
location 76 by releasably connecting legs 110, 120, 122 and 116 to
mounting means 90, 82, 84 and 92, respectively.
It will also be apparent from the above that four quarter-size tanks could
be mounted within the full-size tank base location 76 by assembling two
pairs of quarter-size tanks and then mounting each of the pairs in the
manner just described.
The legs of the tanks are connected to the mounting means by a plurality of
releasable connecting means 118 as best shown in FIGS. 6 and 7. FIG. 6 is
an enlarged view of the left end of FIG. 5 showing the details of
construction of one of the mounting means 120 as connected to the leg 116
of quarter-size tank 30 by one of the releasable connecting means 118. The
view of FIG. 6 is taken along line 6-6 of FIG. 3.
Each of the mounting means such as 120 includes a first pin receiving hole
such as 122 disposed through a substantially vertical wall 124 of rack 74.
Each of the releasable connecting means such as 118 includes a cylindrical
connecting pin 126 constructed to be received through said first pin
receiving hole 122 of said mounting means 120 and an aligned second pin
receiving hole 128 defined in the leg 116 of the base of quarter-size tank
30.
The releasable connecting means 118 further includes a pin retainer means
130 for retaining the connecting pin 126 in the first and second pin
receiving holes 122 and 128.
The connecting pin 126 has an enlarged generally circular head 132 defined
on one end thereof, and includes a radially extending locking bar 134
fixedly attached to head 132 such as by welding. The locking bar 134
extends radially from the connecting pin 118.
The mounting means 120 includes a notch means 136 defined in the mounting
rack 74 for receiving an end 138 of the locking bar 134 as best seen in
FIGS. 6 and 7.
The mounting means 120 includes a tubular member 140 fixedly attached
thereto as by welding, which lies adjacent the notch means 136. The
tubular member 140 has a pair of transverse retaining pin receiving holes
142 disposed therethrough.
The pin retainer means 130 includes a pin 146 having a head 148 defined
thereon with a loop-shaped retainer clip 150 attached to the head 148.
When the connecting pin 126 is placed through the first and second pin
receiving holes 122 and 128, the enlarged head 132 abuts the wall 124. The
connecting pin 126 will then rotate due to the action of gravity upon the
radially extending locking bar 134 until the end 138 of locking bar 134 is
received within the notch 136 and rests against the inner extremity
thereof. Then, the pin retainer means 130 is utilized to retain the end
138 of locking bar 134 in the notch 136. This is accomplished by sliding
the retainer pin 146 thereof through the holes 142 in tubular member 140
so that the retainer pin 146 extends across the notch means 136 so as to
prevent the end 138 of locking bar 134 from rotating out of notch means
136. This holds the connecting pin 126 in place so that the container 30
is held in place relative to the rack 74.
As can best be seen in FIGS. 3 and 6, the mounting means 120 includes a
second notch means 152 on an opposite side of the vertical wall 124 from
the first notch means 136, with an associated second tubular member 154
similar to the tubular member 140. This permits the connecting pin 126 to
be inserted through the first and second pin receiving holes 122 and 128
in either direction. If the connecting pin 126 is reversed from the
position shown in FIG. 6, the locking bar 134 will be received in the
second notch means 152 and the pin retainer means 130 will be connected to
the second tubular structure 154 to retain the locking bar 134 within the
second notch means 152. This feature is particularly advantageous when the
rack 74 is mounted with associated structures so that it is difficult if
not impossible to insert the connecting pin 126 from one direction or the
other.
As can best be seen in FIG. 3, the mounting rack 74 has a length 156 and a
width 158. The mounting rack 74 has a central raised portion 160 best seen
in FIG. 5 which extends generally parallel to the length 156 of rack 74.
As best seen in FIGS. 1 and 6, when the base of one of the tanks 26 or 28,
or an assembled pair of quarter-size tanks 30 and 32 is received on the
rack 74. the raised portion 160 is relatively closely straddled by the
legs such as 116 and 122 of the tanks or assembled pairs of quarter-size
tanks. This aids in positioning the tanks on the rack 74 prior to the time
that the connecting pins 126 are inserted.
Referring now to FIG. 2, it is seen that a second rack means 162,
substantially identical to first rack means 74, is attached to the vehicle
frame 12 adjacent the tank mounting rack means 74. This second rack means
is shown in FIGS. 1 and 2 as being used to mount a portion of the work
platform 34, which as seen in FIG. 2 comes in two substantially square
sections 164 and 166. The work platform sections 164 and 166 each have a
base construction substantially identical to the construction of the base
of a full-size tank such as tank 26, whereby one of the work platform
sections 164 or 166 may be connected to a full-size tank base location on
the second rack means 62. Referring to FIG. 2, an end view is there seen
of the base of second platform section 166 and two legs 168 and 170
thereof are visible. The legs 168 and 170 are constructed substantially
identical to the legs of the tanks and are similarly connected to mounting
means on the second rack means 162.
The platform sections 164 and 166 may also be generally referred to as
pallets having a pallet base including the legs 168 and 170, which pallet
base is interchangeable with the base of one of the full-size tanks such
as 26. Thus, the platform sections 164 and 166 may be utilized as pallets
to load, for example, a stack of bags of dry material or the like thereon
at ground level, and the pallet may then be lifted into place and
connected to the second mounting rack 162. The dry material, such as sand,
would then be readily usable by an operator working on the work platform
34.
The Lifting Apparatus
The details of construction of the lift means 40 will now be described with
particular reference to FIGS. 8-11.
The lifting means or lifting apparatus 40 is physically attached to and
includes as a functional part thereof a portion of the vehicle frame 12,
which may be referred to generally as a base of the lifting apparatus 40.
The lifting apparatus 40, as previously mentioned, includes the load fork
57 having tines 59 and 61 which are received within fork openings 53 and
55 of the pallet base 50 of blender assembly 38. The load fork 57 may also
be generally referred to as a load support means 57 for engaging and
supporting a load as said load support means 57 and said load are moved
between a lowered position as shown in FIG. 10 and a raised position as
shown in FIG. 9 relative to said vehicle frame or base 12. The load
referred to may be the blender assembly 38.
The lifting apparatus 40 further includes lifting arm means 200 connected
at a first pivotal connection 202 to frame 12 and at a second pivotal
connection 204 to load support means 57, for moving the load support means
57 between its said lowered and raised positions.
Lifting apparatus 40 further includes a stabilizer arm means 206 connected
at a third pivotal connection 208 to said load support means 57, and
connected at a fourth pivotal connection 210 to frame 12, for controlling
a rotational orientation of said load support means 57 about an axis 212
(see FIG. 8) of said second pivotal connection 204 relative to said frame
12.
The lifting apparatus 40 further includes sprocket means 214 rigidly
attached to said lifting arm means 200 substantially coaxial with said
first pivotal connection 202.
The lifting apparatus 40 further includes chain means 216 (see FIG. 9)
operably engaged with sprocket means 214, and power drive means 218
mounted on the frame 12 and operably connected to the chain means 216 for
moving the chain means 216 to rotate said sprocket means 214 and to
thereby move said load support means 57 between its said lowered and
raised positions.
The lifting arm means 200 preferably includes first and second
substantially parallel spaced lifting arms 220 and 222 as seen in FIG. 8.
The sprocket means 214 preferably includes first and second sprockets 224
and 226 rigidly attached to said first and second lifting arms 220 and
222, respectively.
The chain means 216 includes first and second chains 228 and 230 operably
engaged with said first and second sprockets 224 and 226, respectively.
The power drive means 218 includes first and second separate power drive
means 232 and 234 operably connected to said first and second chains 228
and 230, respectively.
Each of the first and second power drive means 232 and 234 is a hydraulic
ram having a cylinder 236 thereof mounted on frame 12 and having a
reciprocal rod 238 thereof attached to its respective chain 228 or 230.
Each of the first and second rams 232 and 234 is sized such that it is
capable, in the absence of the other, of lifting a maximum design load of
the load support means 57, thus providing a redundancy safety feature in
the event of failure of one of the rams.
The tines 59 and 61 of the load fork 57 are rigidly attached to a
cylindrical rod 240 best seen in FIG. 8. The rod 240 is rotatingly
journaled in the outer ends of the first and second lifting arms 220 and
222 to define the second pivotal connection 204 previously mentioned.
Rigidly attached to the cylindrical beam 240 of load fork 57 are two
upwardly extending forwardly tilted ears 242 and 244 between which is
received an outer end of the stabilizer arm 206.
A connecting pin 246 is journaled through the upper ends of ears 242 and
244 and through the outer end of stabilizer arm 206 to define the third
pivotal connection 208 previously mentioned.
As is best seen in FIGS. 9 and 10, the first, second, third and fourth
pivotal connections 202, 204, 208 and 210, respectively, define a
parallelogram four-bar linkage. The distance between second pivotal
connection 204 and third pivotal connection 208 is equal to the distance
between first pivotal connection 202 and fourth pivotal connection 210.
Also, the distance between first and second pivotal connections 202 and
204 is equal to the distance between third and fourth pivotal connections
208 and 210.
This parallelogram linkage results in the load fork 57 being maintained
with tines 59 and 61 horizontal throughout the movement of the lifting
means 40.
As is further explained below, the lifting apparatus 40 and any load
carried by load fork 57 can be lowered from its upper position of FIG. 9
to its lower position of FIG. 10 by extending the rods 238 of rams 232 and
234 thus allowing the weight carried by the load fork 57 to rotate the
lifting arms 220 and 222 and stabilizer arm 206 counterclockwise as viewed
in FIG. 9 downward to the position shown in FIG. 10. Similarly, the load
may then be lifted upward from the position of FIG. 9 to the position of
FIG. 10 by retracting the rods 238 of rams 232 and 234.
An upper limit means 248 (see FIG. 11) is provided for limiting upward
pivotal motion of the lifting arm means 200 to define the upwardmost
position of the lifting arm means 200 and the corresponding raised
position of the load fork 57.
As seen in FIG. 11, the upper limit means comprises an adjustable bolt and
locking nut arrangement threaded into a portion of the vehicle frame 12
and arranged to abut the first lifting arm 220 to limit upward motion
thereof at the position shown in FIG. 9. The upper limit means 248 is
adjusted to limit the upward pivotal motion of first lifting arm 220 at a
position slightly short of a vertical position thereof, as indicated in
FIG. 9. This permits the weight of the apparatus and of the load carried
by load fork 57 to rotate the lifting apparatus 40 counterclockwise back
down to the lowered position of FIG. 10 once the lifting force of the rams
232 and 234 is released. Of course, the force exerted by rams 232 and 234
will be gradually reduced so as to slowly lower the load fork 57 and the
blender assembly 38 carried thereby.
As is further shown in FIG. 11, the lifting apparatus 40 includes a latch
means 250 operably associated with the first lifting arm 220 for
releasably latching the first lifting arm 220 in its said upwardmost
position.
With the lifting apparatus 40 latched in its upper position, the load may
be released from rams 232 and 234.
The latch means 250 includes a latch arm 252 pivotally connected to vehicle
frame 12 at pivot point 254. A resilient spring 256 biases the latch arm
252 toward the latched position as shown in FIG. 11.
The latch arm 252 includes a handle 256 which may be grasped by a human
operator to pull the latch arm 252 out of the way of first lifting arm 220
so as to allow first lifting arm 220 to move downward from the position of
FIG. 9 toward the position of FIG. 10. A safety release handle 258 is
pivotally connected to vehicle frame 12 at pivotal connection 260 and is
operably attached to a release pin 262 which extends upward through the
handle 256 so that in order to open the latch means 250, it is necessary
for the human operator first to raise the safety release handle 258
upwards thus moving the release pin 262 downwards out of the way of the
lifting arm 252, and simultaneously the human operator can pull on the
handle 256 to rotate the latch arm 252 counterclockwise as seen in FIG. 11
out of the way of first lifting arm 220.
The latch arm 252 further includes a cam surface 264 constructed on its
rearward end which is engaged by the first lifting arm 220 when the first
lifting arm 220 moves upward from its down position toward its up
position, to cam the latch arm 252 out of the way.
The first and second lifting arms 220 and 222 each include a clamping shelf
means 266, attached thereto, for clamping the pallet base 50 (see FIG. 14)
of blender assembly 38 between the tines 59, 61 and the clamping shelf
means 266 when the blender assembly 38 is in a raised position as
illustrated in FIG. 2. This clamping of the pallet base 50 between the
clamping shelf means 266 and the tines 59, 61 stabilizes the blender
assembly 38 in its raised position for transport by the vehicle 10. This
clamping arrangement causes the blender assembly 38 and the entire lifting
means 40 to be relatively rigidly connected together when the blender
apparatus 38 is in the raised position of FIG. 2.
The lift system 40 provides the capability of supporting the blender
apparatus 38 during transportation. This is contrasted to many prior art
forklift type lifts or tailgate type lifts utilized on other trucks which
can lift structures but cannot support them during transportation. This is
very significant since the blender 38 weighs on the order of three
thousand pounds.
The lifting means 40 further includes a lower limit means for limiting
downward pivotal motion of the lifting arm means 200 to define a
downwardmost position of the lifting arm means 200 short of a position
wherein said second pivotal connection 204 is aligned with said first and
fourth pivotal connections 202 and 210. This lower limit means is provided
by abutment of a lower surface 268 (see FIG. 9) of stabilizer arm 206 with
a cylindrical bushing lower limit means 272 journaled on a frame shaft 270
which defines the first pivotal connection 202.
The frame shaft 270 may be considered a portion of the vehicle frame 12,
and as is best seen in FIG. 8, the lower ends of the lifting arms 220 and
222, along with the sprockets 224 and 226 are all journaled on the frame
shaft 270.
The construction of the lower limit means so as to prevent alignment of
pivotal connections 204, 202 and 210 prevents the four-bar linkage from
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