U.S. patent number 3,672,526 [Application Number 05/061,672] was granted by the patent office on 1972-06-27 for front and side loading attachment for lifting trucks.
This patent grant is currently assigned to Clark Equipment Company. Invention is credited to Howard C. Hansen.
United States Patent |
3,672,526 |
Hansen |
June 27, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
FRONT AND SIDE LOADING ATTACHMENT FOR LIFTING TRUCKS
Abstract
A front and side loader attachment for lift trucks with an
upright in which the fork section is connected to the upright by a
member movable angularly in a horizontal plane from one side of the
carriage to the other side. The member is pivoted at one end on a
line substantially in the longitudinal center of the carriage, and
the fork section is movable to and from lateral positions on a line
perpendicular to the longitudinal center line and is adapted to be
skewed to various angles between the two lateral positions. A load
distributing system is preferably incorporated in the carriage
consisting generally of spaced racks mounted on the upright and one
or more shafts with pinions meshing with the racks.
Inventors: |
Hansen; Howard C. (Battle
Creek, MI) |
Assignee: |
Clark Equipment Company
(N/A)
|
Family
ID: |
22037340 |
Appl.
No.: |
05/061,672 |
Filed: |
August 6, 1970 |
Current U.S.
Class: |
414/666 |
Current CPC
Class: |
B66F
9/147 (20130101) |
Current International
Class: |
B66F
9/12 (20060101); B66F 9/14 (20060101); B66f
009/14 () |
Field of
Search: |
;214/660,730,731,83.24
;187/19 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Sheridan; Robert G.
Assistant Examiner: Oresky; Lawrence J.
Claims
I claim:
1. A front and side loading attachment for a lift truck having an
upright, comprising a carriage having a vertical section connected
to the upright and a horizontal section connected to said vertical
section and projecting forwardly therefrom, a means on said
horizontal section having right angle intersecting X and Y axes
with the Y axis positioned longitudinally with the truck, a
straight track means on one of said axes, an arcuate track means
having a radius the center of which is at the intersection of said
axes, a crosshead on the straight track means of said one axis, a
crosshead on said arcuate track means, an elongated link having a
forward end and being connected at its rearward end to said first
crosshead and connected at its longitudinal center to the second
crosshead, means for moving said second crosshead along said
arcuate track means and indirectly moving said first crosshead
along said straight track means, a fork section pivotally connected
on a vertical axis to the forward end of said link, and means for
skewing the fork section on said vertical axis from one side of the
carriage to the other side thereof.
2. A front and side loader attachment for a lift truck as defined
in claim 1 in which said straight track means is on said Y
axis.
3. A front and side loader attachment for a lift truck as defined
in claim 1 in which a motor mounted on said horizontal section
drives said second crosshead along said arcuate track to move the
forward end of said link from one side of the carriage to the
other.
4. A front and side loader attachment for a lift truck as defined
in claim 3 in which said motor means and said second crosshead are
interconnected by a chain to drive said crosshead in either
direction in said arcuate track means.
5. A front and side loader attachment for a lift truck as defined
in claim 4 in which the vertical axis on the link on which said
fork section is pivotally connected is a vertical shaft and a chain
is mounted on said link for retaining said shaft in a fixed
position relative to the carriage.
6. A front and side loader attachment for a lift truck as defined
in claim 1 in which said straight track means and said arcuate
track means consist of slots in said horizontal section, and in
which said crossheads are disposed in the respective slots, and a
motor mounted on said horizontal section drives the crosshead in
said arcuate track means, and in which a chain interconnects said
motor and the crosshead in said arcuate track means and moves in
said arcuate slot.
7. A front and side loader attachment for a lift truck as defined
in claim 1 in which said carriage has a load distributing system
including a pair of laterally spaced racks mounted on said upright
and interconnecting shaft and pinions meshing with said racks.
8. A front and side loader attachment for a lift truck as defined
in claim 6 in which said carriage includes a load distributing
system having a pair of laterally spaced racks mounted on said
upright and a plurality of interconnecting shafts and pinions
meshing with said racks.
9. A front and side loader attachment for a lift truck as defined
in claim 1 in which said fork section includes a fork frame and a
motor means for raising and lowering said fork frame relative to
said fork section and the horizontal section.
10. A front and side loading attachment for lift trucks having an
upright, comprising a carriage having a vertical section connected
to the upright and a forwardly extending, laterally movable
horizontal section, a means connected to said vertical section and
supporting said horizontal section and having a slidable pivot
means retained substantially on the longitudinal center line of
said carriage, a pivot means mounted on said forward end of said
horizontal section, and a load supporting section journalled on
said pivot means and being movable angularly to face to the front
and to either side of the carriage.
11. A front and side loader attachment for lift trucks as defined
in claim 10 in which the forward end of said horizontal section
moves on a straight line perpendicular to the center line of the
lift truck.
12. A front and side loader attachment for lift trucks as defined
in claim 10 in which said pivot means consists of a shaft mounted
on the forward end of said horizontal section, and a motor is
connected to said shaft for skewing the fork section about said
pivot means.
13. A front and side loader attachment for a lift truck as defined
in claim 10 in which said carriage includes a load distributing
system having a pair of laterally spaced racks mounted on said
upright and interconnecting shaft and pinions meshing with said
racks.
14. A front and side loader attachment for a lift truck as defined
in claim 12 in which said carriage includes a load distributing
system having a pair of laterally spaced racks mounted on said
upright and including a plurality of interconnecting shafts and
pinions meshing with said racks.
15. A front and side loading attachment for lift trucks, comprising
a carriage, a member mounted on said carriage and having at one end
a slidable pivot means movable on a line substantially on the
longitudinal center of said carriage, the other end of said member
being movable from side to side substantially the full width of
said carriage and on a line perpendicular to said first mentioned
line, a fork section pivoted to the member at said other end and
being movable with said member on said perpendicular line and
movable angularly in a horizontal plane from one side of the
carriage to the other side.
16. A front and side loader attachment for lift trucks as defined
in claim 15 in which a motor means is mounted on said carriage for
moving said other end from one side of said carriage to the other
side thereof and thereby moving said fork section from one side of
the carriage to the other side thereof.
17. A front and side loader attachment for lift trucks as defined
in claim 15 in which a motor means is connected to the pivot of
said fork section for moving said fork section between forward
position and to either lateral side position.
18. A front and side loader attachment for a lift truck as defined
in claim 15 in which said carriage includes a load distributing
system having a pair of laterally spaced racks mounted on said
upright and interconnecting shaft and pinions meshing with said
racks.
19. A front and side loader attachment for a lift truck as defined
in claim 17 in which said carriage includes a load distributing
system having a pair of laterally spaced racks mounted on said
upright and including a plurality of interconnecting shaft and
pinions meshing with said racks.
Description
Materials and products are often stored in warehouses,
manufacturing plants, and shipping terminals in large storage rack
structures spaced from one another by aisles used for transporting,
depositing and retrieving loads of material or products in the rack
structures on either side of the aisle. The loading and unloading
of the racks involve the operations of moving the loads
longitudinally in either direction along the aisle and moving the
loads laterally into and from the racks on either side of the
aisle. Sideloading devices require a reach mechanism capable of
moving the load from a central carry position to a laterally
extended position beyond the side of the vehicle. The minimum
travel distance or stroke requirement of the mechanism is equal to
the lateral dimension of the pallet and/or load, plus an additional
several inches of aisle clearance required within the aisle between
the traveling truck and the storage rack structure. Most mechanisms
used in transporting loads do not lend themselves conveniently to
this requirement. For instance, if a conventional pantograph
mechanism is used for such long strokes, its collapsed height is so
great as to severely limit the ability of the device to place loads
in a top storage rack shelf near the ceiling. If a single stage
telescoping arrangement is used for the large stroke required, the
collapsed dimension of the telescope is much greater than the width
of the truck, and a two-stage telescoping arrangement becomes
excessively complex and costly. One known device employs a
combination of two basic mechanisms, consisting of a single-stage
telescope device and a pantograph mechanism, the first device
achieving a portion of the stroke requirement and the pantograph
mechanism extending to acheive the balance of the stroke. Such
arrangements have been inherently unsatisfactory.
Further, in order to perform the two longitudinal and lateral
operations with lift trucks, the aisles between the rack structures
have been relatively wide to permit some lateral maneuvering of the
trucks when a load is being deposited in or removed from the racks,
thus limiting the amount of storage space available for any given
area. The prior lift trucks also have not had the ability to handle
loads on more than one side or to transfer a load from one side to
the other in addition to picking up and depositing a load straight
ahead and directly on the floor, and have often been of limited
capacity and required precise positioning of the truck and the use
of special rack structures rather than conventional shelf type
storage racks.
It is, therefore, one of the principal objects of the present
invention to provide a side loading attachment for fork lift
trucks, which will enable the truck to handle full size pallet
loads in relatively narrow aisles and perform the operations of
loading and unloading directly ahead and on either side of the
truck, and which will pick up and deposit loads and transfer them
from one side to the other near floor level or in any elevated
position.
Another object of the invention is to provide a fork lift truck
attachment which can be mounted on a conventional lift truck with
little or no substantial change in the structure or operating
mechanism of the truck, and which is relatively simple in
construction and design and capable of effectively utilizing
standard, shelf-type rack structures.
Still another object of the invention is to provide a lift truck
which is capable of handling loads to either side and in front
without any lateral supporting means apart from the truck itself,
and which will pick up a pallet load squarely and accurately
without precise positioning of the truck and will move the load
into and from the rack on a straight line at right angles to the
longitudinal center line of the truck.
A further object is to provide a lift truck or the like with a
mechanism which will skew pallet loads to either side of the truck
and move the loads laterally to and from storage spaces, and which
will retract laterally sufficiently to permit the truck to be moved
in narrow aisles while the loads are held in their skewed positions
and also to skew the loads while the truck is in the aisle.
Additional objects and advantages of the invention will become
apparent from the following description and accompanying drawings,
wherein:
FIG. 1 is a side elevational view of a lift truck having the
present attachment or carriage assembly mounted thereon;
FIG. 2 is a top plan view of the lift truck shown in FIG. 1
including the present attachment;
FIG. 3 is a fragmentary top plan view of the present attachment,
showing the attachment in two different positions in an aisle
between two shelf racks;
FIG. 4 is a side elevational view of the present attachment removed
from the truck upright;
FIG. 5 is a front elevational view of the attachment shown in the
preceding figures;
FIG. 6 is an enlarged top plan view of the present attachment,
showing it mounted on an upright of the lift truck;
FIG. 7 is a top plan view of a portion of the attachment operating
mechanism, showing the construction thereof in greater detail;
and
FIG. 8 is a side elevational view of the mechanism illustrated in
FIG. 7.
Referring more specifically to the drawings and to FIG. 1 in
particular, numeral 10 designates generally a lift truck having a
body 12, front and rear wheels 14 and 16, steering wheel 18, seat
20, and an upright 22 on the front of the truck having mounted
thereon a carriage 24 and the present attachment indicated
generally by numeral 26. The lift truck shown in the drawings on
which the present attachment may be used is considered
conventional, for the purpose of the present description, and may
be of any one of a number of well known types including those
powered by a battery driven electric motor or by a gasoline engine.
Hence the details of the lift truck will not be described in detail
herein.
The upright 22 and the carriage 24 mounted on the front of the
truck likewise may be considered conventional for the purpose of
the present description, the one shown briefly consisting of an
outer mast section 30 and inner mast section 32, telescopically
arranged with respect to one another, and a hydraulic cylinder 34
for operating the inner mast section and the carriage mounted on
the front of the upright. The inner and outer sections are each
constructed of lateral channel members and the upright shown in the
drawing embodies a two stage lift system, although the present
attachment could be used with other types of systems. The carriage
24 is mounted for vertical travel with respect to the rails of the
inner section by conventional carriage rollers. Hydraulic fluid is
transmitted to and from the upright and carriage and to and from
the hydraulic actuating mechanisms on the attachment by a plurality
of hydraulic hose (not shown) connected to the hydraulic system of
the truck. The operating mechanisms of the upright and of the
attachment are controlled from the operator's compartment by
control valves in the hydraulic system.
Carriage 24 includes a vertical rear section 40 and a forwardly
projecting horizontal section 42 attached integrally and forming a
rigid structure with vertical section 40, the structure being
reinforced by angularly projecting reinforcing members 44 joined at
their inner end to vertical section 40 and to the upper surface of
horizontal section 42. The carriage is elevated to various loading
and unloading levels by the upright operating mechanism and is so
designed and constructed that it will seat on and operate from the
floor as illustrated in FIG. 1. The attachment which is mounted on
and operated from horizontal section 42 has a link 50 movable over
the upper surface of section 42 and supporting section 60 on which
the two lift forks 62 and 64 are mounted. The forks have a
horizontal pick-up portion 66 and a vertical portion 68 connected
to upper and lower fork bars 70 and 72 and are preferably
adjustable laterally in order to accommodate a wide range of load
sizes. The two fork bars are rigidly connected to a cylinder 74
which in turn is mounted on a post 76 the lower end of which is
rotatably connected to the forward end of link 50.
The link is mounted on the upper surface of horizontal carriage
section 40 in sliding contact therewith, and operates in a manner
to move fork section 60 from a forward position such as that shown
in FIG. 2 into a lateral position shown in FIG. 3 with the forks
projecting to the right side of the truck, and to a lateral
position with the forks projecting to the left side of the truck.
The link also moves the fork section outwardly to the position
shown in the left hand view of FIG. 3, and to an extended position
or to a withdrawn position illustrated in the right hand view of
FIG. 3. The movement of link 50 is controlled by a guide or track
system consisting of a straight slot 80 forming a track means on
the Y axis and an arcuate slot 82 forming a track means with a
radius having its center at the point of intersection 84 of the Y
axis and the X axis, as seen in FIG. 3. The inner end of link 50 is
rotatably connected to a crosshead 90 retained in slot 80 and
adapted to reciprocate therein, and the center of the link is
rotatably connected to crosshead 92 retained in arcuate slot 82 and
adapted to reciprocate therein. The crosshead 92 is driven
throughout the length of the arcuate slot by a chain 94 disposed in
the slot and in a peripheral slot 96 extending along the two
lateral and rear sides of horizontal section 40. The chain is a
roller link type chain and the inner sides of the peripheral and
arcuate slots form a track for the chain rollers. The chain is
driven in either direction by a hydraulic motor 100 mounted on the
inner left hand edge of horizontal section 40, the motor rotating a
motor sprocket 101 which in turn drives the chain. Crosshead 92,
which is connected to the chain, moves along slot 82, and crosshead
90 is moved by means of link 50 along slot 80, i.e. on the Y axis.
As the two crossheads move in their respective slots, the forward
end of link 50 on which post 76 is rotatably mounted moves on the X
axis from right to left. Thus, as the rear end of link 50 is moved
forwardly and rearwardly in slot 80 and the center of the link is
moved on the arcuate path determined by slot 82, the fork section
60 is extended to and withdrawn on a straight line perpendicular to
the longitudinal center line of the truck, from one side or the
other depending upon the initial position of the fork section with
respect to the link.
As previously mentioned, the center for the radius of slot 82 is
the point of intersection 102 of the X and Y axes which intersect
one another at right angles near the forward end of horizontal
section 40. In order for this system to operate in the manner
described, the pivot connection between crosshead 92 and the link
must be equally spaced from between post 76 and the pivoted
connection of the link to crosshead 90. While a crosshead could be
used at the base of post 76 in addition to, or as a substitution
for, crosshead 90, only one crosshead in combination with crosshead
92 is required in order to perform the extending and withdrawing
operation of the fork carriage along the X axis. In either
arrangement, the link would be driven by the chain connected to
crosshead 92 in slot 82.
A chain 110 similar to chain 94 is seated in a groove in the
periphery of link 50 and is trained on a sprocket 114 at the
forward end of the link connected to the bottom of post 76 and at
the rear of the link on a sprocket 116 connected to crosshead 90.
Thus when the forward end of the link moves from one side of
horizontal section 40 to the other side, the post maintains a fixed
radial position relative to the X axis, for reasons which will
hereinafter be more fully explained.
Fork section 60 is slewed to various angular positions with respect
to carriage section 40 by a hydraulic motor 120 which rotates
cylinder 74 through sprockets 122 on the motor and 124 on the
cylinder, and by a chain 126 trained on the two sprockets. The
motor 120 is rigidly connected to post 76 and supported thereon by
bracket 127 at the upper end thereof. The lower section 128 of
cylinder 74 is also moved telescopically with respect to the upper
section 129 by two cylinders 130 and 132 mounted on the lower
section of the cylinder by brackets 134 and 136, respectively, and
connected to cross bar 70 by piston rods 138 and 140. This
auxiliary lift is essential, in that, in lifting a pallet from the
floor, the bottom board of the pallet must be raised above the
upper surface of the link before the fork section is slewed or
moved to any position above horizontal section 40 of the carriage.
The movement of the lift forks upwardly as the lower section of
cylinder 74 is elevated by hydraulic cylinders 130 and 132, tilts
the forks upwardly as illustrated by the broken lines, as a result
of one or more wedge shaped cams 142 engaging a lug 144 on the side
of the cylinders. The tilted position of the lift forks restrains
the load as the load is being further elevated by the carriage 26
and is being transported by the truck. Since shaft 76 is
constrained by chain 110 in any fixed position of link 50,
energization of motor 120 causes cylinder 74 to rotate in the right
or left hand direction about post 76, which in turn causes the
forks to slew right or left in orientation. The arrangement is such
that forks 62 and 64 may be slewed 100.degree. to the left and
100.degree. to the right from straight forward orientation with
respect to the truck.
Carriage 24 is mounted for vertical movement on upright 22 by a
plurality of conventional carriage rollers and the upright lift
cylinder furnishing the upward force for lifting the load; however,
a torque force of substantial magnitude exists when fork section 60
is in one of its lateral positions, such as that illustrated in
FIG. 3. In order to obtain satisfactory performance of carriage 24
on upright 22, the torque force must be distributed or counteracted
to prevent an excessive strain on the upright and to facilitate
easy movement of the carriage on the upright. In the embodiment of
the invention illustrated in the drawings, the torque forces are
transmitted equally to both sides of the outer section of the
upright by a system of squaring shafts and gears, indicated
generally by numeral 150. Each squaring shaft includes a shaft 152,
gears 154 and 155 mounted on opposite ends thereof, and racks 156
and 157 secured to and running the full length of the vertical
members forming the outer section of the upright. The gears 154 and
155 are keyed to the ends of the shaft so that the two gears and
shaft rotate in unison, and the shaft is journalled in vertical
section 40 of carriage 24. The gears of each respective shaft
travel on the two racks 156 and 157 as the carriage is moved
upwardly and downwardly on the upright and carrying a lateral load,
thus distributing the torque uniformly between the two sides of the
upright. The use of the squaring shaft system, in combination with
the fork lift upright frame, serves to rotate the opposing forces
so that the forces are aligned and parallel to the upright members
which can then readily withstand additional in line forces, but
which they might otherwise not be capable of supporting as torque
resulting from a laterally offset load. While only three sets of
shafts and gears are shown in the drawings, a greater or smaller
number of shafts and gears may be used as required.
In the operation of the present side loader attachment for lift
trucks, starting with the truck and attachment in the position
illustrated in FIG. 1, and with a load on pallet P, the truck moves
forwardly, inserting forks 62 and 64 into the pallet slots.
Cylinders 130 and 132 are then actuated to lift the load until the
forks are in the position shown in broken lines. In this position
the load can be moved to any angular position without interference
from link 50 or from horizontal section 42 of the carriage. The
upright power cylinder is then operated to lift carriage 24 from
the floor. With the carriage in the foregoing position, the truck
is maneuvered along an aisle between two sections of shelf racks,
for example, until it reaches the location where the load is to be
deposited. Assuming the load is to be deposited on one of the upper
shelves, the carriage is elevated by the upright to approximately
the level of the shelf and motor 100 is operated to move fork
section 60 laterally, for example, to the right, and simultaneously
motor 120 is operated to slew the fork section to the left, thus
placing the load in position to insert it into the shelf section.
With the forks at the right angle position to the forward direction
of the truck and with the link in its fully right hand position,
for example, the motor 100 is again actuated to move the forward
end of the link along the X axis, thereby moving fork section 60
and the load directly laterally in a straight line into the shelf
section. After the load has been inserted in the shelving, either
cylinders 130 and 132 are operated, or the carriage is lowered to
lower the forks and disengage them from the pallet. The foregoing
operation is then reversed to withdraw the forks from the pallet by
moving link 50 to its right hand position. Thereafter the carriage
can be again lowered and the truck withdrawn from the aisle between
the shelf racks.
As an alternative to the foregoing operational procedure, the
lateral positioning of the load may be performed before the truck
enters the aisle so that the only operations to be performed in the
aisle are the elevation of the load and the lateral movement of
inserting or withdrawing the load. The same operation is performed
to load and unload the shelving on the opposite side of the aisle,
and the attachment can be operated in essentially the foregoing
manner to shift the load from one extended side position to the
other extended side position without withdrawing the truck from the
aisle.
The foregoing operation can be performed in an area only slightly
larger than the width of the truck and attachment, and without the
need of any lateral supporting structure or outriggers to stablize
the truck and/or attachment thereon. The squaring shaft system 150
operates to distribute the load evenly on the upright so that no
undue strain is placed on the upright.
While only one embodiment of the front and side loader attachment
has been described in detail herein, various changes and
modifications may be made without departing from the scope of the
invention.
* * * * *