The present invention relates to a system for lifting loads in an automated guided
vehicle system. Particularly, the present invention relates to a lifting assembly for loading and
5 unloading a load/component utilizing a plurality of screw jacks to facilitate balanced lifting.
BACKGROUND OF THE INVENTION
[002] Automated guided vehicle system is used for transporting loads from one place to
10 another along a predetermined path. Presently, automated guided vehicles (AGVs) are widely
used in the industries requiring material handling. For instance, AGVs are used to transport
raw materials and finished products in nearly every type of industry associated with
manufacturing, logistics and storage of products Such industries include but are not limited
to pharmaceutical, chemical, paper, automotive, product manufacturing, food and beverage,
15 hospitals, warehouse and entertainment industry. An AGV is used in to perform various
functions, such as autonomously loading/unloading, transporting of components or load, or
moving of goods between the shelves or stacking of goods. There are different types of AGVs
depending upon function to be performed by the AGV, mode of load transport, type of the
load, load carrying capacity, type of industry and speed.
20
[003] AGVs are generally equipped with a power source, a guiding technology, a safety
mechanism and lifting/loading and unloading mechanism. There are different types of AGVs
depending upon the task to be performed and the type of industry where it is used. For
instance, unit load AGV are used to transport a single product over a distance. Forklift AGVs
25 are used to transport pallets and Tugger/Towing type AGVs are used to tow/ carry heavy
loads. AGV are also equipped with different types of mechanisms to lift, move, carry or
transfer loads.
[004] WO2020029505A1 discloses an AGV transport vehicle which uses lifting device,
30 where the lifting device includes four sets of screw mechanism provided on a base and a
jacking rotation driving mechanism for driving the screw to rotate. The rotatory shaft of
jacking gear is installed at the center of the four screw systems, drive system transfers lifting
3
motion directly to the base facilitates central lifting of component, Hence, the driving motion
is done through gears only and only has a center lifting mechanism.
[005] The patent application KR20140111785A discloses an AGV for autonomously
5 loading and unloading of component. The system includes a base frame, a traveling unit, a
lifting unit, and a control unit. The lifting unit comprising screw jack to lower and elevate the
base frame on various automation lines of various heights. Here the whole AGV is lifted for
loading and unloading in different height which limits it to transfer only when AGV is
stationary.
10
[006] There are various lifting mechanisms available for loading and unloading of the
load/components which are integrated with AGVs. However, the earlier approaches do not
provide a balance handling for heavier loads at different heights with higher efficiency and
higher flexibility by a moving AGV.
15
[007] Therefore, keeping in view of the problems associated with the state of the art and to
further improvise the efficiency of prior existing lifting mechanism in an AGV system, there
is a requirement of highly efficient lifting arrangement in an AGV system providing higher
load bearing capacity, increased vertical lifting height and higher up down speed.
20
OBJECTIVE OF THE INVENTION
[008] The primary objective of the present invention is to provide a lifting assembly for an
automated guided vehicle system (AGV) for the lifting or loading/unloading of a component.
25
[009] Another objective of the present invention is to provide an AGV with a lifting
mechanism that utilizes screw jack assembly for the vertical lifting or up down movement of
a component.
30 [0010] Yet another objective of the present invention is to provide a screw jack assembly
that utilizes four point lifting arrangement to facilitate balanced lifting.
[0011] Yet another objective of the present invention is to provide self-locking of gears to
make the lifting balanced and sturdy.
4
[0012] Yet another objective of the present invention is to provide an automated guided
vehicle system (AGV) which further improves load bearing capacity, increased lifting height
and higher up down speed.
5
[0013] Other objects and advantages of the present invention will become apparent from the
following description taken in connection with the accompanying drawings, wherein, by way
of illustration and example, the aspects of the present invention are disclosed.
10 SUMMARY OF THE INVENTION
[0014] The present invention relates to an automated guided vehicle system with screw jack
lifting mechanism to facilitate vertical lifting of load/components. The lifting device
comprises of a screw jack assembly that utilizes four point lifting arrangement to make a
15 balanced and sturdy lifting. A driving mechanism comprising a driving motor and a driving
shaft, whereby the driving motor is configured to transmit a lifting force to screw jack
assembly through a drive shaft for lifting the component up down. Further, the lifting device
facilitates self-locking of gears to make the lifting balanced and sturdy. The disclosed lifting
assembly has higher load bearing capacity, improved stroke/lifting height and increased up
20 down speed, thereby reducing takt time resulting higher productivity.
BRIEF DESCRIPTION OF DRAWINGS
[0015] A complete understanding of the present invention may be obtained by reference to
25 the accompanying drawings, when taken in conjunction with the detailed description thereof
and in which:
[0016] Figure 1 shows schematic prospective view of the lifting assembly comprising four
screw jacks mounted on four corners of a base frame and mechanically coupled to each other
30 through drive shaft.
[0017] Figure 2 shows schematic view of a screw jack assembly.
5
[0018] Figure 3 shows top view of the lifting assembly comprising four screw jacks
mechanically coupled to each other.
[0019] Figure 4 shows the side view of lifting assembly.
5
[0020] Figure 5 shows the front view of lifting assembly along with a gear box.
[0021] Figure 6 shows isometric view of complete AGV.
10 DETAILED DESCRIPTION OF THE INVENTION
[0022] The following description describes various features and functions of the disclosed
system and method with reference to the accompanying figure. In the figure, similar symbols
identify similar components, unless context dictates otherwise. The illustrative aspects
15 described herein are not meant to be limiting. It may be readily understood that certain aspects
of the disclosed system and method can be arranged and combined in a wide variety of
different configurations, all of which are contemplated herein.
[0023] Accordingly, those of ordinary skill in the art will recognize that various changes and
20 modifications of the embodiments described herein can be made without departing from the
scope of the invention. In addition, descriptions of well-known functions and constructions
are omitted for clarity and conciseness.
[0024] Features that are described and/or illustrated with respect to one embodiment may be
25 used in the same way or in a similar way in one or more other embodiments and/or in
combination with or instead of the features of the other embodiments.
[0025] The terms and words used in the following description and claims are not limited to
the bibliographical meanings, but, are merely used to enable a clear and consistent
30 understanding of the invention. Accordingly, it should be apparent to those skilled in the art
that the following description of exemplary embodiments of the present invention are
provided for illustration purpose only and not for the purpose of limiting the invention.
6
[0026] It is to be understood that the singular forms “a,” “an,” and “the” include plural
referents unless the context clearly dictates otherwise.
[0027] It should be emphasized that the term “comprises/comprising” when used in this
5 specification is taken to specify the presence of stated features, integers, steps or components
but does not preclude the presence or addition of one or more other features, integers, steps,
components or groups thereof. The equations used in the specification are only for
computation purpose.
10 [0028] The present invention is related to an automated guided vehicle system (AGV) for
autonomously lifting or loading/unloading of a load/component, transporting of components
or load, or moving of goods between the shelves or stacking of goods. AGVs are mobile
robots computer controlled wheel based load carriers that are normally powered by battery
and run on plant or warehouse or logistic transportation industry. The commonly used AGVs
15 are equipped with lifting assembly for material handling.
[0029] The present invention discloses an AGV system equipped with lifting assembly. The
lifting assembly according to the present invention comprises a base frame/chassis, a lifting
mechanism fixed to corners of the base frame and a driving means. The lifting mechanism
20 comprises a plurality of screw jacks configured for vertical lifting of a component. In
particular, the four post screw jack arrangement utilized to make a balanced lifting of the
load/component. Further, the self-locking of screw jack arrangement makes the lifting
balanced and sturdy. The lifting arrangement of the present invention has higher load bearing
capacity, improved stroke/lifting height and increased up down speed, thereby reducing takt
25 time resulting in higher productivity
[0030] In a preferred embodiment, the lifting assembly for an automated guided vehicle
(AGV) system is shown in Figure 1. The system (1) comprises a base frame/chassis (2)
configured to be mounted on an automated guided vehicle (3) and a load lifting assembly (4)
30 connected to the base frame. The load lifting assembly (4) comprises a plurality of screw
jacks (5), a driving means, a top frame (8) and a load supporting arrangement. The driving
means further comprises a drive shaft (6) and a driving motor (7) and a plurality of gear boxes
(11).
7
[0031] The plurality of screw jacks (5) are mounted on the corners of the base frame/chassis
(2). The screw jacks are mechanically coupled to each other and the driving means. All the
screw jacks are coupled to the motor (7) through the drive shaft (6) and gear box (11). The
top frame (8) is mounted on the plurality of screw jacks (5) and is mounted with an
5 arrangement configured to hold the load/ component on it.
[0032] The load supporting arrangement mounted on the top frame (8) further comprises a
skid frame (9) and a cup (10) configured to hold the component on AGV. To achieve vertical
lifting or loading or unloading of a component, the driving motor transmits lifting force to the
10 screw jacks through the driving shaft to lift the component up and down.
[0033] The screw jacks (5) are mechanically coupled to each other by a coupling member,
which herein is a drive shaft (6).As shown in Figure 4, a pair of screw jacks are coupled to
each other by a drive shaft (6) and a gearbox (11). A driving means comprising drive motor
15 (7) coupled to all the four screw jacks through drive shaft (6) and dual gearboxes (11) to
transfer motion. The motor draws power supply from a battery. The motor is connected to
gear box which transfer motion at 1:1 to the plurality of screw jacks through the driving shaft.
Thus, the screw jack basically converts the rotational motion into linear motion. .
20 [0034] The drive shaft (6) is rotatable and performs a synchronized function of raising and
lowering of all the four screw jacks simultaneously. Further, the motor is connected to bevel
gear to produce 1:1 motion transfer to the four screw jacks through the drive shaft. The lifting
system facilitates easy drive mechanism as the four screw jacks are using one common motor
connected at one end of system. As soon as the drive motor (7) actuates, the shaft starts to
25 rotate which further actuates the four screw jacks (5). The drive shaft transfer motion to all
the four lead screw of each screw jack. Thus, the four screw jacks are moved vertically or
raised/ lowered in a synchronized manner.
[0035] Figure 2 shows a schematic view of the screw jack assembly. The screw jack assembly
30 (5) facilitates vertical lifting or loading/unloading of a component. The screw jacks use screw
mechanism to raise or lower the load/component. A screw jack (5) comprises a gear housing
(12) and a lead screw (13). The gear housing (12) is arranged at the base of the screw jack. It
further comprises a rotating mechanism that includes a worm screw and a worm gear. The
8
worm screw of the screw jack assembly arranged in the gear housing is coupled to the driving
motor. As the motor actuates, the worm screw starts to rotate and further transfers the rotating
motion to the worm gear and with the rotation of worm gear the trapezoidal threaded lead
screw linearly moves in upwards or downwards direction.
5
[0036] The load/component is placed on the top frame (8) which is mounted above lead
screw nut (13). The vertical motion of lead screw results in lifting of the load/component
place above it in the vertical direction.
10 [0037] Yet another embodiment of the present invention is self-locking of gears. The lifting
mechanism provides self-locking for gears which lowers the event of system failure and
makes the system robust and more reliable. Self-locking prevents the system from back
driving which is useful in loading and/or holding the loads. Worm gears comprises a speed
reducer which transfers motion to nut, also nut & trapezoidal threaded screw ensures self15 lock during the event of sudden power failure.
[0038] Figure 3 shows top view of the lifting assembly showing four screw jacks
mechanically coupled to each other. Figure 4 shows the side view of lifting assembly. Figure
5 shows the front view of lifting assembly along with a gear box. Figure 6 shows isometric
20 view of complete AGV.
[0039] The screw jack lifting mechanism (5) greatly improves the lifting or
loading/unloading of the components. The four point lifting arrangement can have higher load
bearing capacity i.e. up to 1000 Kg and also, eliminates skidding while carrying large loads.
25 Thus it facilitates stable lifting and greatly improves loading of the component. Further, the
lifting system facilitates easy drive mechanism as the four screw jacks are using one motor at
one end of system.
[0040] Furthermore, the disclosed lifting mechanism is flexible. The shaft can be adjusted
30 freely to fit size and available space of application. The entire lifting mechanism can be fixed
to the chassis of the automated guided vehicle or portable robot or mobile robot. The lifting
mechanism provides self-locking for gears which lowers the event of system failure and
makes the system robust and more reliable.
9
[0041] The lifting mechanism has a large stroke height up to 100mm with up down speed of
1m/min. The lifting arrangement of the present invention can handle car bodies or truck chain
type components. Due to four point lifting the lifting operation is very balanced and sturdy.
AGV with screw jack lifting can be used in automobile industry such as in paint shops for
5 storage and transfer purpose.
[0042] While the present invention has been described with reference to one or more
preferred aspects, which aspects have been set forth in considerable detail for the purposes of
making a complete disclosure of the invention, such aspects are merely exemplary and are
10 not intended to be limiting or represent an exhaustive enumeration of all aspects of the
invention. The scope of the invention, therefore, shall be defined solely by the following
claims. Further, it will be apparent to those of skill in the art that numerous changes may be
made in such details without departing from the spirit and the principles of the invention.

WE CLAIM:
1. A lifting assembly in an automated guided vehicle system, comprising:
- a base frame/chassis (1);
- a plurality of screw jacks (5) mounted on the corners of the base frame/chassis (1)
5 and coupled to each other;
- a top frame (8) mounted on the plurality of screw jacks (5);
- a load supporting arrangement mounted on the top frame (8) configured to hold
the load/component; and
- a driving means comprising a drive shaft (6) and a driving motor (7) and a plurality
10 of gear boxes (11). ;
wherein,
the plurality of screw jacks (5) are coupled to each other by means of a plurality of
gear boxes and the drive shaft (6) and are configured for vertical lifting of a
component;
15 the driving motor (7) is configured to transmit a lifting force to screw jack assembly
(5).
2. The system as in claimed 1, wherein the lifting assembly (4) utilizes four point lifting
arrangement comprising four screw jacks (5) mounted on the four corners of the base
frame/chassis (1).
20
3. The system as in claimed 2, wherein the four screw jacks are mechanically coupled to
each other in a manner that vertical motion of each of the screw jacks are
synchronized.
25 4. The system as in claimed 1, wherein the each screw jack (5) comprises a gear housing
(12) and a lead screw (13).
5. The system as in claimed 1, wherein the screw jack (5) utilizes self-locking of gears
to make the lifting balanced and sturdy.
30
6. The system as in claimed 1, wherein the load supporting arrangement comprises a
skid frame (9) and a cup (10) configured to hold the load/component;
11
7. The system as in claimed 1, the system has load bearing capacity upto 1000 Kg and it
has improved stroke/lifting height of upto 100mm.
5 8. The system as in claimed 1, the system has higher up down speed of upto 1m/min,
thereby reducing takt time resulting higher productivity.