Saluki Engineering Company
Literature Review For:
Belly Pan Jack
Project: F10-56-BELLYPAN
Members:
Alex Gibbs
Ross Heern
Brad Wilson
Blake Thurston
Jason Weber
Matt Lane
Table of Contents
Abstract…………………………………………………………………………...........................3
Introduction………………………………………………………………………………………..3
Chassis and Drive System………………………………………………………………………4-6
Figure 1……………………………………………………………………………………5
Figure 2……………………………………………………………………………………6
Lifting Mechanisms……………………………………………………………………………6-8
Figure 3……………………………………………………………………………………7
Figure 4……………………………………………………………………………………8
Figure 5……………………………………………………………………………………9
Platform Fixture System……………………………………………………………………….9-13
Figure 6…………………………………………………………………………………..10
Figure 7…………………………………………………………………………………..10
Figure 8…………………………………………………………………………………..11
Figure 9…………………………………………………………………………………..12
Figure 10…………………………………………………………………………………12
Figure 11…………………………………………………………………………………13
Current State of Art…………………………………………………………………………..14-16
Figure 12…………………………………………………………………………………14
Figure 13…………………………………………………………………………………15
Figure 14……………………………………………………………………………........16
Conclusion……………………………………………………………………………………….16
References………………………………………………………………………………………..17
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Abstract:
This document includes research information pertaining to portable and stationary lifting
devices that could be found in most mechanic shops. The purpose of this research is to gain
information related to the development of a belly pan jack to aid in the removal and installation
of belly pans on large excavating equipment. This research includes information on current state
of the art developments in this field as well as related patents and subsystems thereof. The areas
covered give a good base of information on which to develop new ideas.
Introduction
The objective of this project is to design and build a jack to assist in removing and
installing belly pans on heavy construction equipment. The jack could be used on bulldozers,
excavators, and haul trucks as well as many other pieces of equipment. This research document
contains a review of the current state of the art designs in this area as well as the subsystems of
the designs. The subsystems include: chassis systems, drive systems, lifting mechanisms, and
platform fixture systems. Current patents pertaining to these systems are integrated into the
body. Despite the fact that development of the proposed project has a relatively specific field
there have been numerous developments in similar ideas, which will be explored in this
document.
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Chassis and Drive System
Most small lifting devices are portable and therefore they are not anchored to the ground.
This means that they must have a base or chassis to support the lifting mechanism. The chassis
can be as simple as a base or foot mounted to one end of the lifting device as seen in Figures 3
and 4. This is the most basic chassis which provides a common mounting base for the
components as well as providing a larger footprint to make lifting the device more stable and
reduce its overall ground pressure. In many lifting devices, the chassis may be a more complex
part of the lifting mechanism. This is displayed in Figure 5 where the base is a link in a four bar
mechanism that allows the lifting surface to be maintained at a desired angle with respect to the
ground [1]. Some hydraulic lifting systems also use the chassis as a fluid reservoir which allows
for less overall components and simplifies the product, such as the bottle jack shown in Figure 1.
Another common component of a portable lifting device chassis is a sub-system that allows the
device to be easily maneuvered on the ground plane. These sub-systems vary greatly in type and
complexity. To allow for movement simple wheels are commonly attached on the extremities of
the chassis. Caster wheels are commonly used in situations where maneuverability and
durability are priorities. A caster wheel is a wheel that pivots around an axis that is off set to the
wheels contact point with the ground, this allows the wheel to track straight when pushed in a
straight line however it can still pivot freely when a lateral force is applied [2]. Figure 1 is an
example of a caster wheel.
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Figure 1: Locking Caster Wheel
Caster wheels are the standard solution to making a small lifting device portable while
supporting a load. The drawback to this system is that the operator must manually move the
device. Therefore if the lifting system is designed to support a mass that is not easily moved by
the operator, a drive system may be incorporated into the chassis. Drive systems can be as
complex as an internal combustion engine coupled with a multi-speed transmission or as simple
as a direct drive electric motor. However, since most lifting devices that require a drive system
use hydraulically powered lifting systems, the most common drive system is a direct drive
hydraulic motor as seen in Figure 2.
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Figure 2: Hydraulic Drive Motor
A hydraulic drive motor works by using hydraulic fluid to spin a turbine inside the motor
which is attached to the drive shaft which protrudes from one end of the motor [3]. A common
way of using a hydraulic drive system on a lifting device is to mount the hydraulic motor directly
to a single wheel and the chassis. By using a single driven wheel along with two caster wheels
the chassis can pivot around the drive wheel which allows the lifting device to not only move
under its own power but also be easily steered by the operator.
Lifting Mechanisms
There are numerous kinds of lifting devices available for many types of applications. One
of the most common types of lifting devices is the hydraulic jack. Like most lifting devices the
hydraulic jack utilizes mechanical advantage to apply a force to an object that is greater than the
jacking force, in order to move an object. Hydraulic jacks are very reliable and can be operated
in several ways. Fig. 3 is a picture of one of the most common ways to operate the hydraulic
jack, by manually manipulating a lever up and down in order to pump fluid from the reservoir to
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the cylinder [1]. An alternative way to operate the jack is by an electrical or mechanical pump, or
by compressed air, which simply takes the place of the manual lever.
Fig. 3: A simple manual hydraulic jack.
Along with the manually operated hydraulic jack, there are also jacks that utilize
compressed air as the working fluid. A pneumatic jack fundamentally operates in the same
fashion as the hydraulic jack, using compressed air instead of oil as the working fluid. Another
type of pneumatic jack is the air bag. The air bag is much simpler than the pneumatic and
hydraulic cylinder jacks. An air bag consists of two plates attached to both ends of a strong bag
usually made of rubber. Compressed air is forced into the bag through a valve, which inflates the
bag and lifts the object. To lower the object, the air is simply released from the air bag. The air
bag is very useful in low clearance areas because the bag can be deflated and compressed to only
a few inches in height. There are also lifting devices that incorporate a simple screw design. The
screw design uses a course threaded rod that goes through a threaded hole on each end of the
mechanism. As the threaded rod is turned, it pulls opposite ends of the lifting mechanism toward
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each other which pushes the top and bottom of the mechanism apart. Fig. 4 below shows the
mentioned mechanism [4].
Fig. 4: Screw design for a scissor jack.
Often times the lifting device is placed in a structural mechanism such as the screw design. The
purpose of the structural mechanism is usually to increase the lifting height or the lifting capacity
of the device. Fig. 4 shows a basic structure mechanism called a scissor jack [4]. Usually a
scissor jack mechanism has more members or longer members than the four shown in Fig. 4 [4].
Multiple linkages can be added to a scissor lift to reach a desired height while only one lifting
device is required. Another type of structural mechanism that is utilized in most floor jacks is the
parallel linkage mechanism. A parallel linkage mechanism is used to keep the lifting surface at a
desired angle, usually horizontal with respect to the ground, while lifting an object. Fig. 5 shows
a parallel linkage mechanism used in a common hydraulic floor jack [1].
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Fig. 5: Floor jack that utilizes a parallel linkage
Platform Fixture System
The platform of most equipment lifts consist of two primary subsystems. The subsystems
include a method of aligning the platform to the object being lifted, as well as, a method of fixing
the platform to the object. The platform can be aligned by using a tilting platform and adjusting it
to fit the object. Individual fixtures can also be used to fit a certain object. Commonly these two
methods can be used in conjunction to form a more custom fit to a particular object.
Several types of tilting platforms are commonly used on lifting mechanisms. Figure 6
shows a transmission jack [5]. This jack uses a two axis pivot. The lift arms support a square
frame that has a pivot attached to the center. This pivot is attached to an adjustable link allowing
the entire lower platform to pivot with the adjustment (50).
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Figure 6: Transmission Jack
This platform also has a pivot located in the center. The two pivoting platforms used in
conjunction with the caster wheels and lift give the ability to adjust to almost any object.
However, if the load is off center of the pivot, a great deal of torque is put on the adjusting link
making it less than ideal for very heavy objects. Figure 7 shows another tilting platform [6].
Figure 7: Belly Pan Hoist with tilting platform
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This platform has a tilting axis on one end of the platform and the adjustment mechanism on the
other. This setup is more stable because most of the elements involved in the adjustment remain
only in compression no matter where the load is centered. However, this lift only tilts in one
direction reducing the versatility of the lift in unlevel situations.
Figure 8: Belly Pan Hoist
Using fixtures allows another method of adjustment for the lift. Figure 8 shows a
platform that allows a threaded rod (26) to be inserted [7]. This rod can be used to adjust the
contact point location between the lift and the object. The screw, however, is limited to only
three locations. The platform also has sliding arms (82) that allow the lift to encompass a wider
load.
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Figure 9: Rubber Inserts
Figure 9 shows another method of fitting the lift to the object. These rubber inserts are
inserted into the platform. The flexibility and variety of these inserts allows for a large range of
applications [8]. The inserts, however, are limited in height due to rubber buckling easily. This
limits there use for shapes that vary greatly in height. The rubber inserts shown in figure 9 could
simply be inserted into a hole in the platform. Using a hole means that the fixture is only held in
place by gravity and is not completely secure in all situations. The threaded hole used in figure 8
Figure 10: T-slot Table
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does give complete security; however, the number of threaded holes limits fixture location. The
slots used to hold the sliding arms in figure 6 and 8 offer a durable and adjustable means of
attaching fixtures, but they only allow adjustability in one direction. Figure 10 shows a T-slot
table. The slots use a t-shaped insert that slide in. The insert is then attached to the fixture with a
bolt which fastens the fixture to the table [9]. This option gives a great deal of flexibility because
the fixture can be slid exactly where it is needed. Methods of securing objects to the platform
vary by application. Figure 6 shows chains being used which are very strong, but the links do not
provide a method of actually tightening the object to the lift. They are used loosely to prevent the
object from sliding. Figure 8 shows arms that extend up and hold the object securely in place.
These are fairly secure because the bolts run through the object being held. This method only
works when designed for a unique object. Ratchet straps provide another method of securing an
object to a platform. The elasticity of the strap and the ratchet action make it possible to secure
almost anything, in addition the straps work well with limited space.
Figure 11 shows the type of ratchet securing device typically shown on semi-trailers for
securing cargo [10]. The disadvantage of using ratchet straps is that all extremities of the object
must be exposed in order to be completely secured.
Figure 11: Ratchet Securing Device
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CURRENT STATE OF THE ART
Currently there are very few devices made for the sole purpose of aiding in the removal
of belly pans. The Belly Pan Hoist made by Hedweld is one of the few designed for this purpose.
Hedweld’s design utilizes two hydraulic jacks that are connected to a scissor lift mechanism
which provides all of the lifting power for the hoist. The maximum safe lifting load of the hoist
is 700kg (1543lb). Also, the hoist has a very wide range of motion, 245mm fully compressed to
1.1m fully expanded. The large front wheel of the hoist is powered by a hydraulic motor. There
are two large caster wheels on the back which, along with the motorized front wheel, make it
easy to maneuver itself and the belly pan once it is removed from the machine. The upper
platform of the hoist is a solid piece of steel with a 360 degree turn table for easy placement of
the belly pan. There is also an angle attachment that attaches to the upper platform which allows
for the removal of angled belly pans. All of the hydraulics on the hoist are powered by
compressed air and all of the controls for the hydraulics are located on the handle of the hoist
[11].
Figure 12: Belly Pan Hoist [11]
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Although there are not many specialized tools built specifically for the removal of belly
pans there are many that perform similar tasks. Patent Number 5,372,353 (figure 13) displays a
truck transmission jack. The jack employs many of the same devices that the Belly Pan Hoist
does. It uses a hydraulic bottle jack that is manually operated and a parallelogram lifting style to
raise the object. On the top of the jack there are two bars that can be adjusted with screws in
order to hold objects that have sloped bottoms. The design of the chassis allows the jack to fully
compress. This gives the jack a very low profile and allows it to fit under trucks that have low
ground clearance. Also, the design of the chassis allows for large caster wheels which make the
jack easy to maneuver on shop floors [12].
Figure 13: Truck Transmission Jack [12]
Patent number 5,833,198 (figure 14) displays a lift table which uses a scissor mechanism
and a lift spring to provide the lift. The lift table is very mobile because it does not rely on
hydraulics or compressed air to power it. As the table is loaded the spring compresses by an
amount that is proportional to the load that is applied which keeps the overall height of the items
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and the table relatively low. There are four wheels on the lift table so that it can be moved easily
once it is fully loaded [13].
Figure 14: Mechanically Operated Lift table [13]
Conclusion:
The research information gained from this document will provide a foundation whereas
to start the design process of the development of the belly pan jack. All related areas of the
proposed jack have been covered including: chassis systems, drive systems, lifting mechanisms,
platform fixture systems, current state of the art devices, and related patents. Undoubtedly this
document alone is not enough information to ensure a successful design however, it has
efficiently provided factual knowledge on which to develop new ideas.
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References
[1] T. H. Ha, “Hydraulic Jack,” U.S. Patent 7 100 897 B2, Sep., 5, 2006.
[2] U. Finkeldey, “Caster Wheel” U.S. Patent 343,787, Feb. 1, 1994
[3] W. Friedrichsen, “Hydraulic Motor”, U.S. Patent 424,516, May 9, 2000
[4] D. L. Engel, “Screw Designs for a Scissors Jacks,” U.S. Patent 5 364 072, Nov., 15, 1994.
[5] J. Garante, “Transmission Jack,” U.S. Patent 3,958,793, May, 26, 1976
[6] "Belly Pan Hoist." Hedweld Engineering Pty Ltd. Hedweld Engineering. Web. 06 Oct. 2010.
<http://www.hedweld.com.au/index.php?Module=Products&Category=4&Product=5>.
[7] V. R. C. Durgan, “Crankcase Guard Jack Utilizing Double Parallelogram,” U.S. Patent
3,937,443, Feb., 10, 1976
[8] “Jack Pad Adapter.” ECS Tuning. Web. 05 Oct. 2010.
<http://www.ecstuning.com/Volkswagen-Golf_IV-TDI/Search/ES251745%2C_ES251835/?utm_campaign=ecsvagjackpad&utm_source=tdiclub&u
tm_medium=forum&utm_content=20th>.
[9] “T-Slot Table.” CFM ITBNA LLC Engineering Design Manufacturing. Web 06 Oct. 2010.
<http://www.itbona.com/ITBONA/STOLLE/stollehome.htm>.
[10] “Winch Construction for Cargo Tie-Down Straps.” U.S. Patent 5,490,749, Feb., 13, 1996
[11] "Belly Pan Hoist." Hedweld Engineering Pty Ltd. Hedweld Engineering. Web. 06 Oct.
2010. <http://www.hedweld.com.au/index.php?Module=Products&Category=4&Product=5>.
[12]West, “Truck Transmission Jack,” U.S. Patent 5,372,353, Dec. 13, 1994.
[13]Graetz, “Mechanically Operated Lift Table,” U.S. Patent 5,833,198, Nov. 10, 1998.
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