[0001] This invention relates to an apparatus for transferring pipe between a pipe rack
and a pipe handling apparatus.
[0002] In the prior art there are various methods and devices for lifting tubulars to and
from a drilling rig floor. One of such methods simply attaches a wire cable to the
pipe and then the cable is lifted by a hydraulic winch which is typically mounted
on a truck parked near the rig.
[0003] Cranes have also been used to lift the pipe. Hydraulic driven chains have been successfully
used too. Pipe transferred by these methods can be dropped on personnel or equipment
below causing severe injury and damage inasmuch as they can weigh thousands of pounds.
Often the pipe must be lifted to heights of forty feet or more. These dangers are
more intense when the apparatus and rig are positioned offshore and subjected to wave,
tidal and wind forces.
[0004] If the pipe is dropped or banged against other structure the threaded ends can be
easily damaged or the pipe bent.
[0005] An apparatus is known from US Patent No." 3.810.553 which enables to transfer tubes
from two magazines or racks, situated on either side of the device, towards a drilling
platform.
[0006] This apparatus comprises :
an elongated main support frame adapted to be positioned in proximity to a pipe rack,
- a first trough positioned on said support frame and located along the pipe rack
- a pipe transferring lift assembly positioned on opposite sides of said support frame,
- a second trough located between the first trough and the floor the drilling rig
to provide a continuous path for the pipe,
- a supporting member to support the first end of second trough,
- a carriage operatively connected to said first trough moving pipe along its length.
[0007] In the cited document, the tube are moved from the magazine or rack, by means of
bars, along an inclined plane as for as the trough which is designed to transport
them to the platform.
[0008] This action often causes excessive wear on pipe especially the threaded ends which
must be protected from such wear.
[0009] This necessary care of the threads and pipe ends creates an extra step in the installation
fo the pipe or other tubular in the hole resulting in a longer cycle time.
[0010] According to the present invention, the apparatus comprises :
- an elongated main support frame adapted to be located close to the pipe rack means,
- an elongated pivotal trough means having one end pivotally coupled to said main
support frame such that said pivotal trough means can be pivoted upward to an inclined
position relative to said main support frame and toward said drilling rig floor and
downward to a generally horizontal position,
- a portion of said pivotal trough means adjacent said pipe rack means comprises a
dump trough means, said dump trough means being adapted to support a lenght of pipe,
- a tilting means for tilting said dump trough means when said pivotal trough means
is in a generally horizontal position, whereby pipe can move laterally between said
pivotal trough means and said pipe rack means when in a tilted position and said dump
trough means is generally flush with the rest of said pivotal trough means when in
an utilted position,
- a pivoting means for pivoting said pivotal trough means between said inclined position
and said generally horizontal position,
- a movable elongated structure adapted to receive and carry pipe and supported for
lenghtwise sliding movement in said pivotal trough means,
- a moving means for moving said movable elongated structure along the length of said
pivotal trough means,
- a coupling means for coupling said elongated structure to said moving means, and
- a holding means for holding said elongated structure to said dump trough means to
allow said elongated structure to tilt with said dump trough means.
OBJECTS OF THE INVENTION
[0011] Accordingly, it is the principal object of the present invention to provide an apparatus
for transferring pipe rack and a pipe handling apparatus.
[0012] Another object of the present invention is to provide an improved tubular handling
apparatus which can be used effectively and safely under varying weather conditions
on offshore units with tubulars of various diameters and lengths.
[0013] A further object of the present invention is to provide a tubular handling apparatus
that has an automatic pipe feeder to attain a pipe transferring cycle time shorter
than that of the drilling crew.
[0014] A further object is to provide an improved pipe handling apparatus that can be easily
moved to different locations on a drilling rig.
[0015] A still further object is to provide a pipe handling apparatus that can transfer
pipe from racks on one side of the apparatus to the other side without necessitating
the use of additional equipment, e.g. a crane.
[0016] Another object is to provide an apparatus that can handle pipe without damaging the
pin ends thereof and that does not require that protective caps remain or be placed
on the pipe ends.
[0017] Other objects and advantages of the present invention will become more apparent to
those persons having ordinary skill in the art to which the present invention pertains
from the following description taken in conjunction with the accompanying drawings.
Figure 1 is a perspective view of a pipe handling apparatus with the pipe transfer
system of the present invention located on one side of the apparatus next to a pipe
rack.
Figure 2 is a side view of the pipe transfer system of Figure 1.
Figure 3 is an enlarged end view of the tilting mechanism for the stacking and unstacking
trough of the pipe transfer system of Figures 1 and 2.
Figure 4 is an enlarged side view of the tilting mechanism for the stacking and unstacking
trough of the pipe transfer system of Figure 1 and 2.
Figure 5 is an end view of the pipe transfer system of Figure 1 and 2 with its stacking
and unstacking trough shown at different elevations and positions.
Figure 6 illustrates a hydraulic system for operating the pipe transfer system of
Figures 1-5.
Figure 7 is a top view of the vertical, pivoted trough of the pipe handling apparatus
of Figure 1.
Figure 8 is a side view of the vertically pivoted trough of the pipe handling apparatus
of Figure 1.
Figure 9 is a side view of the vertically pivoted trough of the pipe handling apparatus
of Figure 1 showing the trough pivoted to an inclined position by hydraulic cylinders.
Figure 10 is a cross-section of Figure 8 taken along the lines 10-10 thereof.
Figure 11 is a cross-section of Figure 8 taken along the lines 11-11 thereof.
Figure 12 is a cross-section of Figure 8 taken along the lines 12-12 thereof.
Figure 13 is a cross-section of Figure 8 taken along the lines 13-13 thereof.
Figure 14 is a top view of a slidable apron attachable to the pipe moving device of
the pipe handling apparatus of Figure 1.
Figure 15 is a side view of the apron and pipe moving device of Figure 14.
Figure 16 is an end view of the pipe moving device of Figures 14 and 15.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] Referring to the drawings, there will be described first the pipe handling apparatus
21 for raising pipe P such as casing, drill pipe, collars, or tubing up to a derrick
floor 25 of a drilling rig (not shown) and for removing the pipe P from the derrick
floor 25. The pipe P is stored in racks 27 on both sides of the apparatus 21. The
apparatus 21 comprises an elongated frame 29 which supports a trough 31 which may
be pivoted upward to an inclined position in alignment with a fixed trough 33 as shown
in Figures 1 and 9 or downward to a horizontal position as shown in Figures 5 and
10-13. Hydraulic cylinders 34 are provided for pivoting the trough 31 upward or downward.
The cylinders are pivotally attached to the frame 29 and their pistons are pivotally
attached to the trough 31. The rear end of the trough 31 is pivotally coupled to the
frame 29 at 35. The fixed trough 33 is supported in an inclined position by the derrick
floor 25 and support structure 36. The trough 31 comprises elongated frame members
37A-37D which support a V-shaped floor 39 along which the pipe P slides. An intermediate
portion 39A of the V-shaped floor 39 is tiltable laterally in either direction when
the trough 31 is horizontal, to dump pipe on either side of the apparatus 21 for storage
in the racks 27. The intermediate position 39A is tiltable by hydraulic cylinders
41. The cylinders 41 have their lower ends pivotally coupled to structure 43 which
is connected to frame members 37A and 37B and their pistons 41A pivotally coupled
to the intermediate portion 39A. Figure 12 illustrates the intermediate portion 39A
being tilted laterally to the left. The cylinders 49 move up and down with the trough
31 as it is pivoted up and down.
[0019] Also provided is a movable member 49 driven by an endless chain 51 for movement along
trough 31 in either direction between its ends 31A and 31B. The bottom 53 of the movable
member 49 is V-shaped and slides along the floor 39. The bottom of the floor 39 has
an elongated slot 53 formed therethrough. A lug 55 having a thin neck 56 extends from
the bottom of the movable member 49. The neck 56 extends through the slot 53 and the
lug 55 is connected to the chain 51 below the floor 39. Means, not shown, is provided
for driving the chain 51 in either direction.
[0020] When it is desired to move pipe from either of the racks 27 upward to the derrick
floor, the following operations take place. The trough 31 is located in its horizontal
position and the movable member 49 is located at the rear end 31A of the trough 31.
A length of pipe is transferred from one of the racks 27 into the trough 31 where
it rests on the V-shaped floor 39. Trough 31 next is pivoted upward to be in alignment
with the fixed trough 33. The endless chain 51 is driven to move member 49 up the
trough 31 to its end 31B. The front end 49A of member 49 engages the lower end of
the pipe P and pushes the pipe P upward in the troughs 31 and 33 until the pipe overlies
the derrick floor. The pipe then is lifted into the derrick by cable hoists and or
elevators. The member 49 is retracted to the rear end 31A or the trough 31; the trough
31 is lowered to a horizontal position; and the process is repeated.
[0021] In moving pipe downward from the derrick floor 25, the trough 31 is raised to be
in alignment with the fixed trough 33 and member 49 moved to an upward position along
trough 31. The cable hoist locates a length of pipe in troughs 33 and 31 and member
49 is moved downward to the lower end of trough 31 to allow the pipe to slide downward
in the trough 31 to position the pipe on the intermediate portion 39A of the floor
39. The trough 31 then is lowered to a horizontal position and intermediate position
39A is tilted laterally to dump the pipe on either side of the apparatus 21 for storage
in one of the racks 27.
[0022] The pipe transfer system for transferring pipe between the racks 27 and the pipe
handling apparatus 21 comprises a pair of aligned arms 61 and 63 located on the side
of the pipe handling apparatus 21 and next to one of the pipe racks 27. In Figure
1, one pair of arms 61 and 63 are shown on the right of the apparatus 21 next to the
right rack 27. The ends 61A and 63A of arms 61 and 63 are pivotally coupled to the
frame 29 at 65 and 67. The opposite ends 61B and 63B of arms 61 and 63 may move to
an upper position above the catwalk 69 and to a lower position below the catwalk 69
as shown in Figures 1, 2 and 5. In Figure 2 the arms 61 and_,63 are shown in dashed
form in their upper positions.
[0023] A hydraulic system is employed for moving the ends 61B and 63B of arms 61 and 63
together to upward or downward positions or to any level in between. The hydraulic
system comprises a pair of cylinders 71 and 73 having their ends pivotally coupled
to the frame 29 at 75 and 77. The pistons 81 and 83 of the cylinders 71 and 73 are
pivotally coupled to arms 61 and 63. In Figure 2, the pistons 81 and 83 are shown
pivotally coupled at 85 and 87 to ears 89 and 91 which are connected to arms 61 and
63 respectively. When the pistons 81 and 83 are forced outward of their cylinders,
the ends 61B and 63B of arms 61 and 63 are moved upward and when the pistons 81 and
83 are moved inside of their cylinders, the ends 61B and 63B of arms 61 and 63 are
moved downward. Referring to Figure 6, the hydraulic system for operating the cylinders
71 and 73 comprises an oil reservoir 93, a pump 95, a four-way directional control
valve 97 and appropriate flow lines.
[0024] Pivotally coupled to the ends 61B and 63B of arms 61 and 63 is a stacking and unstacking
trough 101 for carrying pipe between the rack 21 and the pipe handling apparatus 21.
The trough 101 can be pivoted laterally in either direction to allow pipe to be loaded
onto and from the trough 101. Referring to Figures 2-6, the mechanisms for coupling
the trough 101 to the ends 61B and 63B of the arms 61 and 63 and for tilting the trough
101 will be described. Tilting mechanisms 103 and 105 are provided at each end of
the trough 101. The ends 61B and 63B of arms 61 and 63 have lugs 107 and 108 secured
thereto respectively and which extend laterally outward. The lugs 107 and 108 are
rotatably coupled to tilting mechanisms 103 and 105 respectively allowing the arms
61 and 63 to move up or down together carrying the length of the trough 101 in a horizontal
position. Each of tilting mechanisms 103 and l05 is the same. Tilting mechanism 103
will be described in detail. The lug 107 is rotatably located in an aperture l09 formed
through a bearing member 111. Member 111 is rotatably mounted on an upper shaft l13
which is supported by two mounts 115 and 117 fixedly secured to the trough 101. The
shaft 113 freely extends trough apertures 115A and 117A formed through mounts 115
and 117 and through aperture 111A formed through member 111 whereby the mounts 115
and 117 can rotate about the shaft 113 and the shaft 113 can rotate relative to member
111. A rotary actuator 121 is fixedly secured to the trough 191 by way of a plate
123 which is secured to the actuator 121 and to the trough 101. The actuator 121 has
a lower shaft 125 which can be rotated in opposite directions. The lower shaft 125
is fixedly secured to a linkage 127 which is coupled to the shaft 113. The linkage
127 has an aperture 127A which freely receives the shaft 113 whereby the linkage can
rotate about the shaft 113. When the actuator 121 rotates its shaft 125 in one direction,
the linkage 127 is rotated causing the linkage to turn about the shaft 113 and hence
tilt the actuator 121 and the trough 101. In Figure 3, the trough 101 is shown in
dottedlines tilted laterally in opposite directions. In Figure 3, the actuator 121
is not shown tilting with the trough for purposes of clarity.
[0025] The rotary actuator 12 is a commercially available actuator hydraulically actuated.
Referring to Figure 6, it comprises a cylinder 129 having two pistons 131 and 133,
with a rack 135 connected between the pistons. The rack 133 engages a pinion 139.
The shaft 125 is an extension of the pinion 139. When pressure is imposed on one side
of the cylinder 129 it drives the piston and the rack in one direction to rotate the
pinion 139 and hence the shaft 125. On the opposite side of the cylinder the pressure
is released. In Figure 6, member 140 is the cylinder for the rotary actuator 141 for
the tilting mechanism 105. Actuator 141 is the same as actuator 121. The cylinder
140 has two pistons 142 and 143 and a rack 145 connected between the pistons for rotating
a pinion 146 from which extends a shaft similar to shaft 107. Both actuators of mechanisms
103 and 105 are operated simultaneously by hydraulic fluid from reservoir 93 and pump
95 for driving their shafts in the same direction for tilting the trough 101. Four
way valve 143 is employed for controlling the direction in which the two actuators
121 and 141 rotate their shafts and hence the direction in which the trough 121 is
tilted.
[0026] The arms 61 and 63 and trough 101 operate in the following manner to transfer pipe
between the rack 27 and the pipe handling apparatus 21. Assume that pipe is to be
transferred from apparatus 21 upward to the rack 27. The arms 61 and 63 will be located
such that the trough 101 will be just below the catwalk 69 in a non-tilted position
whereby the V of the trough 101 will be straight up. In this position, the upper edge
of the trough 101 is located close to the catwalk 69 with very little space between
the trough edge and the catwalk 69 such that pipe rolling outward on the catwalk 69
will roll into the trough 101. The intermediate position 39A of the floor 39 of the
trough 31 is tilted laterally to dump a length of pipe onto the catwalk 69. From the
catwalk, the pipe will roll into the trough 101. The arms 61 and 63 then are raised
simultaneously to raise the trough 1
01 with the trough held in a non-tilted position. As the trough is raised, its length
will be held horizontal. The trough thus will cradle and carry the pipe upward with
no longitudinal movement of the pipe in the trough 1
01. Thus the pipe cannot roll off of the trough, nor can it slide off of the trough
longitudinally. When the trough 101 reaches the top of the rack 27, upward movement
of the arms 61 and 63 will be terminated and the trough 101 will be tilted laterally
in a direction to dump the length of pipe onto the top of the rack 27. The trough
101 will be moved to a non-tilted position and the arms 61 and 63 and trough 101 moved
downward to repeat the process.
[0027] For transferring pipe from the rack 27 to the pipe handling apparatus 21, the arms
61 and 63 and trough 101 operate in the following manner. Assume that pipe is to be
transferred from an upper row of pipe on the rack 27 to the pipe handling apparatus
21. The arms 61 and 63 will be located such that the trough 101 will be just below
the top row of the pipe on the rack 27 with the trough 101 in a non-tilted position
whereby the V of the trough 101 will be straight up. A length of pipe will be pushed
into the trough 101. The arms 61 and 63 will then be lowered simultaneously with the
trough 101 carrying the length of pipe downward in a horizontal position. When the
trough 101 reaches the level of the catwalk 69, downward movement of the arms 61 and
63 will be terminated and the trough 101 will be tilted laterally in a direction to
dump the length of pipe into the catwalk 69 where it will roll into the trough 31.
The trough 101 will be moved to a non-tilted position and the"arms 61 and 63 and trough
101 moved upward to repeat the process.
[0028] A pair of arms 61 and 63 and a laterally tiltable trough 101 as described above will
be located on both sides of the apparatus 21 for transferring pipe between either
rack 27 and the apparatus 21.
[0029] When the incline of the troughs 31 and 33 is small, the pipe may not slide down the
trough from the .-derrick floor by gravity. Referring now to Figures 1, 7, 8, 11,
12 and 14-16, there will be described in slidable apron 151 removably attachable to
the pipe moving device 49 of the pipe handling apparatus 21 for carrying pipe from
the derrick floor 25 down the troughs 33 and 31 when there is little or no height
differential between the derrick floor 25 and the frame 29 of the pipe handling apparatus
21. The apron 151 comprises a V-shaped member slidable on the floor 39 of the trough
31. An aperture 153 is formed close to the rear end 151A of the apron 151 into which
is fitted a triangular shaped securing member 155 which projects upward from a forward
extension of the neck 56 of member 49. The aperture 153 does not extend all of the
way to the rear end 151A of the apron 151 but is spaced therefrom a short distance.
The member 153 slants downward toward its forward end whereby the member 155 may be
inserted into the aperture 153 by moving the member 49 forward while the apron 151
will ride upward on the member 155 as it moves forward until it reaches full length
of the aperture 153 at which time the apron will drop down the the member 155 located
in the aperture 153. When the member 49 is moved forward by the chain, its front end
49A will engage the rear end 151A of the apron and push the apron 151 forward along
the trough 31. For drawing pipe from the derrick floor, the apron 151 will be pushed
onto the fixed trough 33. A length of pipe will be loaded onto the apron 151 and the
member 49 will be moved backward by the chain 51 pulling the apron 151 and hence the
pipe backward whereby the pipe may be loaded onto the rack 27. When the member 49
moves backward the rear end 155A of the member 155 engages the rear end 153B of the
aperture 153, pulling the apron 151 backward. As seen in Figures 7, 11, and 12, the
intermediate or dump portion 39A of the floor 39 of the trough 31 has two elongated
apron holding strips 161 and 163 formed along its top outer-edges. When the -apron
151 is pulled onto the intermediate portion 39A, the outer edges 151B and 151C of
the apron slide under the strips 161 and 163 whereby the apron is held to the intermediate
or dump portion 39A. Thus when the trough 31 is lowered to a horizontal position and
the dump portion 39A is pivoted laterally, the apron 151 also will be tilted laterally
allowing the pipe to be dumped onto the catwalk 69 for loading onto a rack 27 next
to the apparatus 21. During dumping operations by the dump portion 39A, member 49
will not be located above the dump portion 39A. When the apron 151 is tilted laterally
by the dump portion 39A, its aperture 153 is moved above the member 155. However,
when the apron is moved back in place by the dump portion 39A, the aperture 153 will
fit around the member 155 whereby the movable member 49 may push the apron along the
trough 31 to the fixed trough 33.
[0030] Although the apron 151 is used primarily for drawing pipe from the derrick floor
for loading on the rack, it is to be understood that it would be used for moving pipe
from the rack 27 to the derrick floor. The apron 151 also has advantages in that it
protects the main troughs 31 and 33 from wear. A teflon like coating may be applied
to the underside of the apron 151 to minimize friction.
[0031] When the height differential between the derrick floor 25 and the frame 29 is sufficient
such that the pipe will slide down troughs 33 and 31 by gravity, the apron 151 may
be removed as well as the securing member 155. Member 155 may be removably secured
to the forward extension of the neck 56 of member 49 by bolts.
[0032] Instead of employing the strips 61 and 63 to hold the apron 151 to the dump portion
39A, the apron 151 may have a thin neck extending down from its bottom with an enlarged
lug attached to the thin neck. The thin neck will extend trough the slot 53 with the
enlarged lug located below the floor 39. This arrangement allows the apron 151 to
slide on the floor 39 yet holds the apron 151 to the dump portion when it is tilted
for dumping purposes. In this embodiment, the apron 151 may be coupled to the member
49 by securing member 155 to the forward extension of the neck 56 of member 49 through
the aperture 153 of the apron 151 when the aperture 153 of the apron 151 is over the
forward extension of the neck. The apron 151 may be removed by removing member 155
and by sliding the apron forward when the trough 31 is at a slightly inclined position
to remove the lower thin neck of the apron from the slot 53 at the forward end of
the trough 31.
[0033] Preferably the apron 151 will be longer than the length of pipe it will carry.
1. An apparatus (31) for transferring pipe (P) or the like between the floor (25)
of a drilling rig and a pipe rack means (27) characterized by :
- an elongated main support frame (29) adapted to be located close to the pipe rack
means,
- an elongated pivotal trough means (31) having one end pivotally coupled to said
main support frame such that said pivotal trough means can be pivoted upward to an
inclined position relative to said main support frame and toward said drilling rig
floor and downward to a generally horizontal position,
- a portion (39A) of said pivotal trough means adjacent said pipe rack means comprises
a dump trough means, said dump trough means being adapted to support a length of pipe
,
- a tilting means (41) for tilting said dump trough means when said pivotal trough
means 16 in a generally horizontal position, whereby pipe can move laterally between
said pivotal trough means and said pipe rack means when in a tilted position and said
dump trough means is generally flush with the rest of said pivotal trough means when
in an untilted position,
- a pivoting means (34) for pivoting said pivotal trough means between said inclined
position and said generally horizontal position,
- a movable elongated structure (151) adapted to receive and carry pipe and supported
for lengthwise sliding movement in said pivotal trough means,
- a moving means (51) for moving said movable elongated structure along the length
of said pivotal trough means,
- a coupling means (155) for coupling said elongated structure to said moving means,
and
- a holding means (161,163) for holding said elongated structure to said dump trough
means to allow said elongated structure to tilt with said dump trough means.
2. The apparatus according to claim 1, characterized by said tilting means (41) is
mounted to said pivotal trough means.
3. The apparatus according to claim 1, characterized by said holding means (161, 163)
allows said elongated structure to slide lengthwise relative to said dump trough means.
4. The apparatus according to claim 1, characterized by said coupling means (155)
includes a removable coupling means (155) for incoupling said moving means from said
elongated structure when said elongated structure is positioned on said dump trough
means and said tilting means tilts said dump trough means.
5. The apparatus according to claim 4, characterized by said removable coupling means
(155) includes an aperture means (153) formed through the bottom of said movable elongated
structure near one end thereof, and a securing means (49) connected to said moving
means and extending upwards, said securing means being adapted to be removably fitted
into said aperture means from below the bottom of said movable elongated structure.
6. The apparatus according to claim 1, - characterized by said elongated structure
(151) includes a forwardmost portion adapted to extend beyond the end of said pivotal
trough means (31) adjacent said drilling rig when said moving means has moved said
elongated structure to the end of said pivotal trough means.
7. The apparatus according to claim 6, further characterized by a trough (33) fixed
to said drilling rig floor and in alignment with said pivotal trough means when said
pivotal trough means is in said pivoted position, A said forwardmost portion (151)
being adapted to slide onto said fixed trough.
8. The apparatus according to claim 1, characterized by said elongated structure (151)
is adapted to support the entire length of a length of pipe.
9. The apparatus of claim 1, characterized by said dump trough means (39A) including
an elongated tilting tray (39) adapted to support a length of pipe, and said tilting
means (41) is mounted to said pivotal trough means.
10. The apparatus of claiml, characterized by said pivotal trough means (31) includes
a V-shaped pipe support floor (39),
said elongated structure is supported by and sliding on said pipe support floor, and
said holding means (161, 163) holds said elongated structure to said pipe support
floor when said elongated structure is positioned on said dump trough means.
11. The apparatus of claim 10, characterized by said holding means includes a holding
strip means (161, 163) attached to said pipe support floor on said dump trough means.
12. The apparatus of claim 1, characterized by said holding strip means (161, 163)
comprises a pair of opposed guide members positioned to engage the outer edges of
said elongated structure.
13. The apparatus of claim 1, characterized by said holding means includes, said pivotal
trough means (31) including a pipe support floor (39) on which said elongated structure
(151) slides, a neck member attached to and depending from said elongated structure,
said neck member passing.through an opening (53) in said pipe support floor, and a
lug means attached to the outer end of said neck member and positioned to engage a
lower surface of said pipe support floor (39).
14. The apparatus of claim 1, characterized by said tilting means (41) including an
extendable means (41) connected at one end to said pivotal trough means and at the
other end (41A) to said dump trough means for tilting said dump trough means selectively
to either side of said pivotal trough means,
said pivotal trough means (31) including at least two spaced longitudinally frame
members(37A, 37B),
said extendable means (41) being connected to pivotal trough means at a location inside
said frame members and to said dump trough means at a location between said frame
members,
said extendable means including a pair of cylinder means (41) attached on opposite
sides of said dump trough means,
a cylinder connection means (41A) attached to and positioned below said dump trough
means and between said frame members,
said pair of cylinder means including a first cylinder (41) pivotally coupled at one
end to said pivotal trough means and a second end pivotally coupled to said cylinder
connection means and a second cylinder (41) pivotally coupled at one end to said pivotal
trough means and a second end pivotally coupled to said cylinder connection means,
and
said cylinder means (41) being adapted so that when said first cylinder second end
extends relative to said first cylinder first end to cause dump trough means to tilt
said second cylinder second end extends relative to said second cylinder first end
but a lesser extension distance than said first cylinder second end extends.
15. The apparatus of claim 14, characterized by said cylinder connection means (41A)
includes a horizontal plate means.