US3338586A

US3338586A - Portable hydraulic lift truck

Info

Publication number: US3338586A
Application number: US514970A
Authority: US
Inventors: Albert D Kirlin
Original assignee: Ind Mfg Company
Current assignee: Industrial Manufacturing Co
Priority date: 1965-12-20
Filing date: 1965-12-20
Publication date: 1967-08-29
Anticipated expiration: 1984-08-29

Description

Aug. 29, 1967 A. D. KlRLl-N 'PORTABLE HYDRAULIC LIFTTRUCK 2 Sheets-Sheet l Filed Dec. 20, 1965 w f. /Z m J2 la@ i /J w Aug. 29, 1967 Filed Dec. 20, 1965 A. D. KIRLIN PORTABLE HYDRAULIC LIFT TRUCK 2 Sheets-Sheet 2 United States Patent O 3,338,586 PQRTABLE HYDRAULIC LIFT TRUCK Albert D. Kil-lin, Pocatello, Idaho, assignor to Industrial Manufacturing Company, Pocatello, Idaho, a corporation of Idaho Filed Dec. 20, 1965, Ser. No. 514,970 9 Claims. (Cl. 280-5.3)

This invention relates to a lift truck and more specifically to a portable hydraulic lift truck.

Portable lift trucks are commonly utilized to move heavy articles, such as appliances, barrels of bulk products, and pallets of materials, from one location to another. It is frequently necessary to raise or lower the article being transported from one level to another. Most portable lift trucks, While being well adapted to facilitate the moving of an object on one plane, are not suited for moving a heavy object from one level to another.

With known portable lift trucks it is necessary, when moving a load from one level to another, to disconnect the load from the truck and to raise or lower the load to the desired level. The process of raising or lowering the heavy load usually requires the combined efforts of several men or the use of hoists, jacks, and similar devices. Once the load has been raised or lowered, it is often necessary to again connect the loa-d to the hand truck for additional movement. The time and effort which are wasted by disconnecting the load from a hand truck, raising the load manually or with separate hoisting equipment, and reconnecting the load to the hand truck, will be readily apparent.

Therefore, one of the objects of this invention is to provide a portable lift truck which is well adapted for moving a load between two levels and for moving the load on a given level.

Another object of this invention is to provide a portable lift truck which eliminates the necessity of disconnecting the truck from the load when moving the load between two levels.

Another object of this invention is to provide a portable lift truck which eliminates the use of separate lifting machinery or manual effort to raise or lower a load.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following description, taken in connection with the accompanying drawings wherein:

FIG. l is an elevational view of the portable hydraulic lift truck;

FIG. 2 is a detail sectional view along the line 2-2 of FIG. 1;

FIG. 3 is a perspective view of the hydraulic lift truck being used to raise a load;

FIG. 4 is a perspective View of the portable hydraulic lift truck immediately after raising the load; and

FIG. 5 is a schematic drawing of the hydraulic system utilized in the lift truck.

Referring now to the drawings in greater detail, the construction of hydraulic lift truck is shown in FIGS. 1 and 2. The hydraulic lift truck 10 has a load frame 12, an extension frame 14, and a hydraulic pump means 16 to move the extension frame 14 relative to the load frame 12. When the hydraulic pump means 16 is actuated, the frame 14 will move relative to the load frame 12 to raise or lower a load on frame 12.

Considering the load frame 12 in greater detail, two

side members

18 and 20 are connected at their lower end to a load engaging plate or bar 22. The two

side members

18 and 20 are substantially parallel to each other and, at the end of the side members opposite from the load plate or bar 22, have handles 24 and 26 connected integrally with the side members.

Bottom rail members

28 and 30 are connected to the upper end of the

side members

18 and 20 adjacent to the handles 24 and 26 (see FIG. 2). The

bottom rail members

28 and 30 are also connected to the

side members

18 and 20 by means of

support members

32, 34, 36, 38, 40 and 42. The support members 32 to 42 may be utilized as hand grips when moving the hydraulic lift truck from one position to another.

The hydarulic lift truck is supported by

main wheels

44 and 46 which are connected to a main axle 48. The main axle 48 is substantially parallel to the load plate or bar 22 and is supported from the

side members

18 and 20. When the lift truck is moved from one location to another, on a given plane, the load is positioned on the load plate or bar 22 in the usual manner (see FIGS. 3 and 4) and the

main wheels

44 and 46 are rolled along the surface while supporting the load carried by the lift truck. When the lift truck is utilized to move a load along a single horizontal plane, the lift truck functions in the same manner as other lift trucks presently in use. It should 'be noted that the load plate or bar 22 could, as will be apparent to those skilled in the art, be replaced by a lift fork or other known load engaging devices. The load itself is cradled between the two '

side members

18 and 20 and retained there by the strap 49 in a known manner. The load will rest against two

cross members

50 and 152 which are connected between the two

side members

18 and 20 of the hydraulic lift truck.

The extension frame 14 includes a support bar 54 which is normally positioned directly behind and substantially parallel to the load plate or bar 22 (see FIG. 2). Two

parallel stabilizer bars

56 and 58 are connected to opposite end portions of the support bar 54. The two

stabilizer bars

56 and 58 slide telescopically in the hollow tubular side members 18 and 20 (see FIG. l). The suppo'rt bar 54 and the two

stabilizer bars

56 and 58 are extended by the hydraulic means 16, from the position shown in FIG. 2 to the position shown in FIG. 3. The

side members

18 and 20 guide the movement of the stabilizer bars relative to the load frame 12. The

stabilizer bars

56 and 58 may be retracted telescopically into the Side members 18 and Z0 by hydraulic means, which will be explained in greater detail later, to the position shown in FIG. 2.

The hydraulic means 16 includes a pump 62 which is supported between the two

side members

18 and 20 on a cross plate 60 near the upper portion of the lift truck. The cylinder member 64 is connected to the hydraulic pump 62 and is supported in a position intermediate, and parallel to, the side members 18 and 2li by the

cross members

50 and 52. The ram member `65 is slidably positioned in the cylinder 64 and is connected to the support bar 54 at connection 66 (see FIG. 1) between the two

stabilizer bars

56 and 58.

The pump `62 is actuated by oscillating pump handle 68. Torsion bar 70 transmits the oscillations of the pump handle 68 to a lever 72 and link 74. The

linkage

72 and 74 is connected to the pump piston by the connection member 76. When the pump handle 68 is oscillated, the oscillation will cause the pump piston to pump hydraulic lluid under pressure into the cylinder 64. When the high pressure lluid enters into the cylinder 64, the ram member 65 will be displaced outwardly from the cylinder 64 to extend the frame 14 relativemto the load frame 12. It should be noted that when the extension frame 14 is being moved relative to the load frame 12 that the

stabilizer bars

56 and 58 will maintain the support bar 54 in a position which is substantially parallel to the load plate or bar 22.

The pump 62 has a Irelief or exhaust valve 78 to eX- haust the high pressure il'uid in the cylinder 64 to a relatively low pressure reservoir `80 (see FIG. 5) and to thereby permit the extension fra-me 14 to be retracted back to the position shown in FIGS. 1 and 2. The extension frame 14 is retracted back to the position shown in FIGS. 1 and 2 by the action of two

spring members

82 and 84 which are located within the

stabilizer bars

56 and 58 and are connected to the support bar 54 at

connection points

86 and 88. The two

springs

82 and 84 extend the length of the stabilizer ba-

rs

56 and 58 and are connected to the

side members

18 and 20 at

connection plugs

90 and 92 in the upper ends of the

side members

18 and 20. It will be apparent that the spring members `82 and 84 will cause the extension frame 14 to be retracted telescopically back into the

side members

18 and 20 whenever the relief or exhaust valve 78 is positioned to exhaust the high pressure fluid within the cylinder 64 to the relatively low pressure reservoir 80.

The schematic drawing of the hydraulic circuit means for the lift truck is shown in FIG. 5 The exhaust or relief valve 78 connects the reservoir 80, through

hydraulic lines

94, 9S and 96, to the pump 62, and to the cylinder 64. The pump 62 is connected to the cylinder 64 by the hydraulic line 98.

The pump 62 can draw hydraulic fluid, from the reservoir 80, through the hydraulic line 94, valve 78 and line 96. When the valve 78 is in a rst position high pressure hydraulic fluid, from the pump 62, will force the ram member 65 to move the extension frame 14 outwardly relative to the load frame 12. When the relief or exhaust valve 78 is rotated to a second or relief position, the reservoir `80 is connected to the cylinder 64 and the cylinder 64 will be in uid connection, through

lines

94 and 95, with the reservoir 80. With the valve 78 in the relief position the ram `member `65 will be forced telescopically into the cylinder 64, under the influence of the two

spring members

82 and 84 to exhaust the hydraulic -uid from the cylinder to the reservoir 80.

In addition to the extension frame and hydraulic means, the load frame 12 has connected thereto a pair of

auxiliary wheels

100 and 102 which are supported on an auxiliary wheel axle 104. The auxiliary wheel axle 104 is connected to the main axle 48 for the

main wheels

44 and 46 by `

suspension bars

106 and 108. The suspension bars pivot about the main axle 48, as shown in FIG. 2. The

auxiliary wheels

100 and 102 can pivot from a storage position, shown in dotted lines in FIG. 2, between the two

side members

18 and 20 to a support position extending rearwardly from the load frame, shown in solid lines in FIG. 2. The auxiliary wheels are normally held in the storage position by spring member 110 which is coaxial with the main axle 48. The spring member 110 is connected to the side member 20 at one end and to the suspension bar 108 at the other end. While only one spring member 110 has been shown, it will be apparent that a similar spring member could be connected to the suspension bar 106 and the side member 18.

When the auxiliary wheels are pivoted from the storage position, shown in dotted lines in FIG. 2, to the stupport position, shown in solid lines in FIG. 2, a latch means 112 engages the end of the suspension bars 106 and 108 to retain the auxiliary wheel in the support position. The latch means 112 includes a latch pawl 114 (and a similar latch pawl not shown for the other suspension bar 108) which is supported on the axle 116 for pivotal movement relative to the

side members

18 and 20. The latch pawl 114 is normally pivoted forward to the position shown in FIG. 2 under the iniluence of spring 118.

When the auxiliary wheels are moved from the storage position to the support position, the rounded or cam surface 120 will cam the nose 122 of the latch pawl 114 to the left of the position shown in FIG. 2 until the nose 122 of the latch pawl 114 clears the end of the suspension bar 106. The nose 122 of the latch pawl 114 will then engage a notch 124 in the suspension bar'106. When the 4 suspension bar 106 is engaged by the latch pawl 114i, as shown in FIG. 2, the

auxiliary wheels

100 and 102 will be locked `against movement back to the storage position land will provide support for the lift truck (see FIG. 4).

When the auxiliary wheels are to be returned to the storage position, the operator of the lift truck will actuate a latch release lever 126 by pressing on pad 12S at the end of the latch release lever 126. When the latch release lever 126 is depressed, the lever will cause the pawl 114 to swing to the left of the position shown in FIG. 2 and thereby release the suspension bar 106. The two latch pawls, for the suspension bars 106 and 108 are interconnected -by connector bar 127. Thus the depression of the latch release lever 126 will release both latch pawls. The suspension bar 106 and the

auxiliary wheels

100 and 102 will pivot when the latch release lever 126 is depressed, to the storage position under the iniuence of the spring member 110. It will be apparent from FIG. 2 that the latch release lever 126 and the pad 128 are positioned between the two

side members

18 and 20 where the latch release lever will not be accidentally engaged while using the auxiliary support wheels to support the lift truck.

From the foregoing description of the auxiliary wheels, it will be apparent that the

auxiliary wheels

100 and 102 may be utilized to support the lift truck in the upright position shown in FIG. 4. When it is desired to use the lift truck without the support of the auxiliary wheels, it is merely necessary to press the latch release lever and the auxiliary wheels will pivot to the storage position intermediate the two

side members

18 and 20. When the auxiliary wheels are in their storage position the lift truck may be utilized in the normal manner. The auxiliary wheels, in the storage position, will be out of the way and will not interfere with the normal use of the lift truck. The

main wheels

44 and 46 provide the support for the lift truck when it is being rolled along a horizontal surface. The

auxiliary wheels

100 and 102 are utilized primarily to support the lift truck in an upright position, or to pivot the lift truck, when moving between levels, in a manner to be explained more fully subsequently.

For the purpose of affording a more complete understanding of the invention, it is advantageous to now provide a functional description 0f the mode in which the component parts thus far identified cooperate. It is apparent that with the auxiliary wheels in their storage position and the extension frame retracted that the lift truck may be utilized in the same manner in which prior art lift trucks are commonly used. When it is desired to raise a load from a lower level, such as level 130 of FIG. 3 to a higher level 132, the lift truck is irst positioned with the

bottom rail members

28 and 30 contacting a corner 134l of the upper surface 132. In this position the side members should be at approximately a ifteen degree angle with the vertical. The relief or exhaust valve 78 is positioned so that the uid from the reservoir 80 may be passed through the line 94, the valve 78, and the line 96 to the pump 62. The pump handle 68 is oscillated to cause the pump to force the hydraulic iiuid under pressure into the line 98 and the cylinder `64. The ram member 65 will then force the load frame 12 and the load to move vertically upward relative to the support bar 54.

It should be noted that the support bar 54 is positioned with the angled lip 136 flat against the surface 130 (see FIG. 3). The continued oscillation of the pump handle 68 will cause the load `frame to be displaced upward relative to the support bar 54 and ram `65. When the load frame has reached the position shown in FIG. 3, with the

main wheels

44 and 46 contacting the corner-134 of the upper surface 132, the

auxiliary wheels

100 and 102 are pivoted, from the storage position, to the support position, shown in solid lines in FIG. 2. The lift truck is then rotated or pivoted around the axle 104 and the

auxiliary wheels

100 and 102. In this position the entire load of the lift truck is taken by the

auxiliary wheels

100 and 102. The truck is then pulled slightly back from the edge 134 of the surfacey 132 with the main wheels 44 and '46 just above the surface 132. The lift truck is then rocked or pivoted forward to the position shown in FIG. 4. It should be remembered that the extension frame 14 is still extended and the lift truck cannot, therefore, 4be moved for a relatively large distance back from the corner 134 of the surface 132. y

-Once the lift truck has been positioned as shown in FIG. 4, the relief valve 78 may be rotated to the relief position to connect thecylinder 64 directly with the reservoir `80. The force of the two

spring members

82 and 84 on the support bar 54 will cause the extension frame to be retracted to the position adjacent the load engaging member 22 (shown in solid lines in FIG. 4). The lift truck may then be moved slightly further back from the corner 134, and the

auxiliary wheels

100 and 102 retracted to their storage position intermediate the two

side members

18 and 20.

The procedure for lowering a load from the upper surface 132 to the lower surface 130 is merely a reversal of the previously set forth operation for raising a load. Thus, when a load is to be lowered, the lift truck is moved to the edge of the surface with the

auxiliary wheels

100 and 102 locked in a supporting position. The lift truck is then moved slightly forward, supported by both the

auxiliary wheels

100 and 102 and the

main wheels

44 and 46, so that the main wheels are adjacent the edge' of the surface 132. The pump valve 78 is then positioned so that the pump 62 is connected directly to the reservoir 80, so that the high pressure uid from the pump may be transmitted to the cylinder 64. The pump handle 68 is then rotated to cause the pump to move the ram member 65 downward relative to the load frame 12. It should be noted that the extension frame 14 will just clear the corner 134 of the surface 132.

When the support bar 54 has been placed with t-he angled lip 136 flat against the surface 130 (as shown in FIG. 3), the lift truck is then tilted slightly forward to take the weight of the load frame off both the auxiliary wheels and the main wheels, and to place the weight onto the support 'bar 54. The auxiliary Wheel members are then returned to the storage position by actuating the latch release lever 126. The lift truck will now appear substantially as shown in FIG. 3, with the exception :of the fact that the

main wheels

44, 46 will be positioned slightly higher relative to the surface 132. rI'he relief or exhaust valve 78 is then turned to exhaust the fluid from t-he cylinder 64 to the reservoir 80. The weight of the load on the load frame of the lift truck will cause the load to sink slowly to .the ground. The rate of descent of the load may be controlled by the gradual opening of the relief valve 78. The

bottom rail members

28 and 30 will slide against the corner 134 while the load is descending. Thus the lift truck operator will merely have to hold the upper end of the frame.

The lift truck may be easily manipulated when the load frame is being tilted as the

main wheels

44, 46 are moved to clear the corner 134 during both the lifting and lowering operations. The manipulation of the load frame, while raising and lowering the load, is facilitated by the fact that the center of gravity of the load will be to the right (as seen in FIG. 3) of the support bar 54 and will thereby tend to stabilize the Ilift truck when it is being manipulated. Thur, the weight of the lift truck and load will be supported in a -relatively stable position by the

bottom rail members

28 and 30 which will bear against the corner 134 while the l-oad is being moved from one level to another.

From the foregoing description, it will be apparent that my novel lift truck permits a single man to raise and lower a relatively 'heavy load from one level to another without disconnecting the load from the lift truck. The lift truck may be utilized as a standard lift truck with the auxiliary wheel members retracted to their storage position. The auxiliary wheel members may also be placed in the support position to retain the lift truck in an upright position. In addition, the auxiliary wheels provide a fulcru-m around which the lift truck may be pivoted when positioning the lift truck relative to the edge of a surface for raising or lowering ra load. Since both the pump handle 68 and the auxiliary wheels may be placed in an unobtrusive storage position, the normal hand operation of the lift truck is not in any way impeded 'by the hydraulic lift means. The hydraulic lift means .is an integral part of the lift truck, and t'he necessity of positioning and maintaining auxiliary lifting equipment is eliminated when my portable hydraulic lift truck is utilized for moving load-s.

The specic example herein shown and described is considered to be primarily illustrative. Various changes in the structure of the load frame, extension frame and hydraulic means will, no doubt, occur to those skilled in the art; and these changes are to be understood as forming a part of this invention insofar as they fall within the spirit and scope of the appended claims.

What is claimed is:

1. A portable lift truckV comprising a frame means for supporting a load, said frame means including a rst side member, a second side member spaced apart from and substantially parallel to said first side member, a load engaging means, a lirst end portion of said load engaging means connected to an end portion of said rst side member, a second end portion of said load engaging means connected to an end portion of said second side member, main wheel means mounted adjacent to said load engaging means, auxiliary wheel means pivotally mounted adjacent said m-ain wheel means, said auxiliary wheel means being pivotable from a rst storage position Ito a second position for supporting said frame means, and latch means to retain said auxiliary wheel means in said second position supporting said frame means; an extension means slidably connected to said frame means and movable relative to said frame means; and a hydraulic means mounted on said frame means and connected to said extension means to move said frame means relative to said extension means.

2. A lift tnuck as set forth in claim 1, wherein said main wheel means includes a main axle mounted adjacent said load engaging means, a iirst main wheel mounted on a first end portion of said main axle, and a second main wheel mounted on a second end portion of said axle; and said auxiliary wheel means includes a first suspension -bar pivotably mounted on sai-d main axle, a second suspension ybar pivotally mounted on said main axle and spaced apart from and substantially parallel to said first suspension bar, a irst auxiliary wheel mounted adjacent an end portion of said iirst suspension bar, and a second auxiliary wheel mounted adjacent an end portion of said second suspension bar.

3. A lift truck as set forth in claim 2, whe-rein said latch means includes a rst latch pawl pivotally mounted adjacent said first suspension bar, a second latch pawl pivotably mounted adjacent said second suspension bar and a latch pawl release means mounted adjacent to said rst land second latch pawls, said latch pawls being positioned to engage the adjacent suspension bar when said auxiliary wheel means is pivoted to said second supporting position and said latch pawl release means 'being adapted to move said rst and second latch pawls to release said suspension bars when said latch pawl release means is actuated to enable said auxiliary wheel means to pivot to said first storage position.

4. A portable lift truck comprising a frame means for supporting a load, an extension means slidably connected to said frame means and movable relative to said frame means, said extension means including a support bar, a iirst stabilizer member connected to said support ybar and guided by said fra-me means for sliding movement relative to said frame means, :a second stabilizer member connected to said support bar spaced apart from and substantially parallel to said first stabilizer member, said second stabilizer member being guided by said frame means for sliding movement relative to said frame means; and a hydraulic means mounted on said frame means and connected to said extension -means to move said frame means relative to said extension means, said hydraulic means including a fluid reservoir, pump means mounted on said frame means and connected to said fluid reservoir, cylinder means connected to said pump means and spaced apart from and substantially parallel to said first and second stabilizer members, valve means connected to said pump means and said fluid reservoir to control the flow of Ihigh pressure fiuid from sa-id pump means to said cylinder means, said valve means being movable to a first position to conduct fluid from Isaid pump means to said cylinder means and to a second position to conduct diuid Ifrom said cylinder means to said rese-rvoir, and ram means, a first end portion of said ram means being connected to said support bar, and the second end portion of said ram means being positioned in said cylinder means :and guided by said cylinder means for sliding movement relative to said cylinder means, said hydraulic pump means supplying fluid to said cylinder means to displace said ram means relative to said cylinder means.

5. A lift truck as set forth in claim 4, wherein said extension means includes spring means connected to said support bar and said frame means to move said support bar to a position adjacent said frame means when said valve means is in said second position.

6. A portable lift truck comprising a frame means for supporting la load, said frame means including a first side member, a second side member spaced apart from and substantially parallel to said first side member, a load engaging means, a first end portion of said load engaging means connected to said first first side member, and a second end portion of said load engaging means connected to said second side member; said extension means includes a support bar positioned substantially parallel to said load engaging means, a first stabilizer member connected to said support bar and guided by said first side member for sliding movement relative to said frame means, and a second stabilizer member connected to said support bar and guided by said second side member for sliding movement relative to said frame means; an extension means slidably connected to said frame means and movable relative to said frame means; and a hydraulic means mounted on said frame means and connected to said extension means to move said frame means relative to said extension means, said hydraulic means including a iiuid reservoir, pump means mounted on said frame means and connected to said fiuid reservoir, cylinder means connected to said pump :means and spaced apart from and substantially parallel to said` first and second side members, valve means connected to said pump means and said fiuid reservoir to control the fiow of fluid from said pump means to said cylinder means, said valve means being movable to a fi-rst position to conduct fiuid from said pump means to said cylinder means and to a second position to conduct fluid from said cylinder means to said reservoir, and ram means, a first end portion of said ram means being connected to said support bar and a second end portion of said ram means being positioned `within said cylinder means and guided by said cylinder means for sliding movement relative to said cylinder means, said ram means being displaced relative to said cylinder means by fluid from said pump means when said valve means is in said first position.

7. A lift truck as set forth in claim 6, wherein said extension means further includes spring means connected to said support bar and said frame means to move said support -bar to a position adjacent said spring means when said valve means is in said second position.

8. A lift truck as set forth in claim 6, wherein said frame means further includes main wheel means mounted adjacent to said load engaging means, auxiliary wheel means pivot-ally mounted adjacent said main wheel means, said auxiliary wheel means being pivotal from a first storage position intermediate said first and second side lmembers to a second position for supporting said frame means, and latch means to retain said auxiliary wheel means in said second position.

9. A lift truck as set forth in claim S, wherein said main wheel means includes a main axle mounted adjacent said load engaging means, a first main wheel mounted on a first end portion of said main axle, and a' second main wheel mounted on a second end portion of said main axle; and said auxiliary wheel means inculdes a first suspension bar pivotally mounted on said main axle, a second suspension bar pivotally mounted on said main axle spaced apart from and substantially parallel to said first suspension bar, a first auxiliary wheel mounted adjacent an end portion of said first suspension bar, and a second auxiliary wheel mounted adjacent said second suspension bar; and said latch means includes a first latch pawl pivotally mounted adjacent said first suspension bar, a second latch pawl pivotally mounted adjacent said second suspension bar, and a latch paw! release means mounted adjacent' to said first and second latch pawls, said latch pawls being positioned to lock the adjacent suspension bar when said auxiliary wheel means is pivoted to said second position and to release said adjacent suspension bar when said latch pawl release means is actuated to enable said auxiliary wheel means to pivot to said first storage position.

References Cited UNITED ST ATES PATENTS 2,192,396 3/ 1940 Burch.

2,608,258 8/1952V Jenkins 280-5.3 X 2,616,720 11/1952 Knoth 280--5-3 X 2,740,637 4/1956 Cononelos ZBO-5.3 2,834,602 5/1958 Hanson 28o- 5.3 3,053,546 9/1962 Muirhead 280-5,3

LEO FRIAGLIA,A Primary Examiner.

Claims

1. A PORTABLE LIFT TRUCK COMPRISING A FRAME MEANS FOR SUPPORTING A LOAD, SAID FRAME MEANS INCLUDING A FIRST SIDE MEMBER, A SECOND SIDE MEMBER SPACED APART FROM AND SUBSTANTIALLY PARALLEL TO SAID FIRST SIDE MEMBER, A LOAD ENGAGING MEANS, A FIRST END PORTION OF SAID LOAD ENGAGING MEANS CONNECTED TO AN END PORTION OF SAID FIRST SIDE MEMBER, A SECOND END PORTION OF SAID LOAD ENGAGING MEANS CONNECTED TO AN END PORTION OF SAID SECOND SIDE MEMBER, MAIN WHEEL MEANS MOUNTED ADJACENT TO SAID LOAD ENGAGING MEANS, AUXILIARY WHEEL MEANS PIVOTALLY MOUNTED ADJACENT SAID MAIN WHEEL MEANS, SAID AUXILIARY WHEEL MEANS BEING PIVOTABLE FROM A FIRST STORAGE POSITION TO A SECOND POSITION FOR SUPPORTING SAID FRAME MEANS, AND LATCH MEANS TO RETAIN SAID AUXILIARY WHEEL MEANS IN SAID SECOND POSITION SUPPORTING SAID FRAME MEANS; AN EXTENSION MEANS SLIDABLY CONNECTED TO SAID FRAME MEANS AND MOVABLE RELATIVE TO SAID FRAME MEANS; AND A HYDRAULIC MEANS MOUNTED ON SAID FRAME MEANS AND CONNECTED TO SAID EXTENSION MEANS TO MOVE SAID FRAME MEANS RELATIVE TO SAID EXTENSION MEANS.