Adjustable Lug Wrench
Content
ADJUSTABLE LUG WRENCH
Aying, Abjie S ; Batuto, Marson Renzel C ; Ochea, Eden S
ABSTRACT
Unlocking lug nuts with initial axial tension present in it
provides a problem especially in users that are not physically fit
as others. Common tool that is used to handle such problem is
either a cross wrench or an L-type wrench which offers minimal
length that will serve as a force multiplier applied. In designing,
Human centered approach was used in order for the users to
have a lug wrench that is efficient yet safe and ergonomic. The
design includes a sliding/adjustable handle that is longer than
usual thus making the task in standing posture rather than
sitting. Minimum dimension of the tool was calculated and
simulated through NX 6 to see critical areas that needs changes.
1. INTRODUCTION
Owning a car, it is important to have the necessary tools in performing
basic maintenance operations. One of the problems in changing tires is
achieving the initial axial tension force needed in loosening the nut by the
use of a lug wrench. Existing designs uses longer handles to address this
problem but longer handles turns to be a hindrance in fully loosening the nut
due to its length. This paper intends to design a tool (lug wrench) that
requires minimal effort from the user and to lessen the time in
loosening/tightening of a Nut.
As old as problem existed, many tools
are invented. One of the new patented to handle such problem to loosen
and tighten a nut of a car tire is A cross-bar socket wrench with a rotatable
gripping handle at one end and a socket-engaging tip at the other. The said
tool was to effectively elongate the working disposition of the device and to
assist in retention during high torque operation (Lucy, 2002). While there are
innovations in performing the task, The L-type and the cross wrench are still
commonly used. The L-type wrench uses longer handles as force multiplier
while the traditional cross wrench has shorter handle compared to an L-type
wrench but has more sizes of bolts that it can loosen (Collins, 2014).
From the current lug wrench tools that is mentioned above, the
common thing is that it focuses only on one aspect of the work which is
either achieving the initial axial tension force needed to loosen the nut or
only to loosen it faster when the nuts are already loosened and simple
turning of the nuts with less force is needed. The gaps of the existing design
is important especially for car users which is not physically fit as others
which needs a tool that will do the task faster and by only using single tool
for both on applying the force needed and faster loosening of the nut.
With the following concepts and considerations, a tool was intended to
be designed. Human centered approach was used to make a design that
aims to make a lug wrench that will maximize the capacity of the material to
be used at the same time making it safe and ergonomic. The design is also
envisioned to simultaneously use only a single tool that can do the task of
achieving the initial axial tension force needed and eliminate the hindrance
of using longer handles in fully getting the nut out of the rim.
2.
LITERATURE REVIEW
2.1 Standards for car wheels installation for bolts/lug nuts
Lug nut is an essential part of a wheel. it is usually made of alloy steels,
aluminum and even titanium. The main purpose of a lug nut is to attach the
wheel to the axle of a car. In order to perform efficiently, it requires proper
torque which is given by the manufacturer. Commonly, car manufacturer
requires 80-100 lb-ft of torque. Failure to acquire these standards may result
to in efficiency, damage to the wheel and car (reinalt , 2015).
Model
Year
Torque requirement
Ford
Aspire
1994-97
85 ft-lbs
Contour
1994-97
85 ft-lbs
Probe
1989-97
85 ft-lbs
All other models
Honda ( all models)
1984-99
1984-04
100 ft-lbs
80 ft-lbs
Hyundai ( all models)
1986-05
80 ft-lbs
1996-00
175 ft-lbs
Chevrolet / GMC
C30 HD (DRW) 5/8-18
Silverado/Sierra HD(DRW)
5/8-18
175 ft-lbs
1999-05
Table 1. car manufacturers standard torque requirement in wheels
2.2 Current Practice, Body Strains, Posture.
Current practice in changing tires involves using hydraulic jack to partially lift
the car, chock (Fig2.2.1) to secure the vehicle from moving forward or backward
before using a wrench in loosening the lug nut. Lastly, the tires will be changed
by new ones and the lug nuts wheel be screwed back again to connect the wheel
to the axle of the car. All of this operation is being done simultaneously in a
sitting posture (fig2.2.2)
2.3 Handle/ Grips
Fig 1. (Choking of wheel)
changing tires
Fig 2. Common posture in
2.3 Grips/ handles
The handle of a tool is necessary in performance of the operation. It serves as the
point of input force by the user to perform the intended work. According to Drury
that said for maximum strength to be applied to the handle and for it to be more
ergonomic, the diameter of it should at least be 3-4 cm (1.1"-1.57") (Dreyfus, H
1972 and Drury, C.G 1980). Grip strength on the other hand will be the basis on
how does or how well the user will hold properly the handle as well as the work
piece. It is also been find out that greatest grip is experienced in the standing
position (Teraoka, 1979). Grip strength was moderately correlated. With overall
body strength in every old and oldest population (Smith, T et al).
2.4 Existing Design
A lug wrench was invented a long time ago; one of the earliest patents was
published by Falk Charles R. in the year 1959. Since then, many innovations have
been made to handle such problem of loosening /tightening a lug nut. commonly,
car owners uses a cross wrench (Fig 3) or an L-type (Fig 4) while some uses new
innovations such as Pneumatic torque wrench (Fig 5) which is an electric
pneumatic wrench with interchangeable tool head attachments, used for
installing and removing nuts (thesaurus.com) next would be a Ratchet wrench
(Fig 6) this tool has a mechanism that consist a bar or a wheel having inclined
teeth into which a pawl drops so that the motion be imparted to the bar only be in
one direction or rotation.
Fig 3. Cross wrench
Fig 4. L-Type Wrench
Fig 5. Pneumatic torque wrench
Wrench
Fig 6. Ratchet
3. DESIGN AND METHODOLOGY
The design of the lug wrench was focused to achieve a human centered tool
that will enable the intended users to perform the task efficiently and safely.
It is an approach to design and develop something that aims to make things
more usable and ergonomic. Sometimes human centered approach tries to
go extra mile and seek new factors like psychology and sociology just to
satisfy users (berg 2001). In getting the dimensions needed for the
adjustable lug wrench, the first step was to get the necessary factors that
will be the basis of the design. These factors are torque requirement, safe
pushing/pulling force of a user, and the material to be used. When
information is gathered, the length and thickness of the material to be used
was calculated by the use of Bending stress and torsional stress formulas.
Lastly, calculated dimension was simulated through Nastran NX6 to see
critical parts that needs minor modification.
4. DESIGN CALCULATIONS
Seen below is the design of a lug wrench that is longer than usual since it will
be used in a STANDING posture. Fig 4.1 is the position in unlocking the nut
from its initial tension. When initial tension is already eliminated, the lug
wrench (fig 4.2) will be adjusted in terms the angle of the Part B. This setup
will allow users to fully loosen a nut while standing with the use of universal
joint connected between part A and B. To better understand the new
dimensions of the wrench, a wheel and average Filipino men having 5’ 3.7”
height(lozada, 2014)was used.
B=3.45
feet
Should
er
level
Elbo
w
level
Figure 4.A Unlocking from initial tension
loosening the nut
Figure 4.B fully
Figure 4.C Kinematic analysis of 4A
analysis of 4B
Figure 4.D Kinematic
Materials: ASISI 148-58 (Sys=60 ksi)
Safe Force to be exerted by the user = 50.6 lbs
( CCOHS, 2009)
Torque requirement (based on table) for SUV & minivans
=175 lb-ft = 2100 lb-in.
Chevrolet(Silverado)
Factor of safety = Nsy 1.5 ( for universal joint = 4 )
Table2. Variables to be used to find the dimensions
For solving the length of B:
The first step is to calculate the length of B as this serves as the force
multiplier to loosen the nut. (The initial tension used in the equation
was
Figure5.
Parts of the
based on torque requirement of Chevrolet Silverado having 175Wrench
lb-ft since it
has the biggest torque requirement among private cars)
Torque = Force x Distance
where: distance is the length of B
T=FxL
L=
T
F
175 lb−ft
= 50.6 lbs
=3.458 ft
For solving the inner diameter (di) of part "A"
Part A of the Wrench is analyzed to have a combination stress. The two
stresses are torsional stress bending stress. With these two stresses, Inner
diameter was calculated to be 0.919inch.
Sds
Nsy
=Sb +Ts
Assumed dimensions:
outer diameter = 1 in
Sds
Mc
Tr
+ J
Nsy =
I
Where:
The cross
sectional area is hollow
cylindrical and the factor of
∴ di=0.919587 in.
safety is 1.5
Figure6. FBD of part A
For solving the inner of diameter of
B1
The hollow cylindrical tube used in part B is analyzed to have bending and
torsional stress. With the two stresses, Inner diameter at a minimum was
calculated to be 0.9881 inch.
Sds
Nsy
=Sb +Ts
outer
diameter = 1.125 in
Sds
Nsy
Mc
I
+
∴ di=0.9881
in.
=
Tr
J
Figure7. FBD of part B (hollow)
For solving the diameter of
B2
(solid part of B for the adjustable handle)
The same from the hollow cylindrical tube in part B, this part still experiences
same type of stress. The only different is that this part is solid. After
calculating, a diameter of 0.7898 inch was found.
Sds
outer diameter = 1.125 in
Nsy =Sb +Ts
Where: The cross sectional area is solid, C =
D
2
Sds
Nsy
,I=
=
πD
64
Mc
I
4
+
Tr
J
∴ di=0.7898
in.
For solving the diameter of universal joint
The universal joint consists of 4 connecting point. A special material of
chrome steel was used. This material has yield strength of 295000 psi. Two
calculate its diameter, the figure from a cross bearing was transferred into a
single cantilever beam type (Figure8). With this, simple bending stress
formula was used thus attaining a diameter of 0.4169inch
0.5”
Figure8. FBD of universal joint
Sds
Nsy
D
where: C = 2
=Sb
,I=
π D4
64
, Sb =295000 psi
, Nsy = 4
Sds
Nsy
=
Mc
I
∴ D=0.41699
in.
For solving the thickness of the YOKE
From the torque requirement based on table 2, a force was applied in the
length of the yoke which is .75 inch. With that, a force of 2800 was
calculated. To simplify the part, it is analyzed like a cantilever beam (Fig9.)
and a force of 1400 was applied since there are two supports in a yoke.
Lastly, it was calculated through bending stress and the thickness of
0.1448inch is the result.
Figure9. FBD of the Yoke
Sb =
Mc
I
Sb rectangle =
b h2
6
Where
Yield strength =Sb=295000psi
0.75inch(t 2)
295000 =
6
∴t=0.1448
in.
Stress analysis.
Seen below is the Stress analysis of the Yoke and universal joint. From figure
10, it is observed that the max stress experienced by the yoke is not near
the design stress. The difference in two values was just taken as a factor of
safety. From figure 11, the design stress was near the max stress
experienced given by NX6. It is due to minor modification done to improve
the diameter of the cross bearing from .0417inch to 0.5169inches at the
critical area near the four corners of the bearing. With the simulated parts, it
is safe to expect that the following dimension of the two parts will handle the
stresses along the operation of loosening a nut.
Figure10. Yoke stress analysis
Joint Stress analysis
Figure11. Universal
Stress analysis.
From figure 12, it is seen that the max stress (33650 psi) was near the design
stress 0f 40000 pounds per square inch. It is also seen in figure 13 to have a
max stress of 43000 psi. Observing from the two figures, it is evident that
the critical parts are those that are connected to the universal joint rather
than the input point which is the handle. From the results in the simulation, it
assures that the following dimension was calculated correctly thus making
the part uses minimal material possible and performs the task without
breaking the material given the results and the factor of safety being done.
Lastly, parts can still be maximized. Looking at Figure 12, it is seen that the
solid part used for sliding the handle experiences little stress compared to
the other parts. With that observation, it is possible to taper the part which
only experiences a stress ranging from 1040 psi-7560psi.
Figure12. Universal joint stress analysis
Part A stress analysis
Figure13.
5. SUMMARY OF DESIGN
The adjustable lug wrench is divided into parts. (1) Is the part that secures
the tool to the wheel. It locks the two parts (Lug nut and wrench) in order for
the lug nut to be loosened. (2) Is a Yoke. This part is connected to the
universal joint to transmit rotation from B to A. (3) is a universal Joint. This
specific part allows motion or rotation from one distinct body to another at
an angle. (4) Is a hollow cylindrical tube. This part is intended to be hollow
for storage purposes due to the length of the wrench. The space inside the
cylinder will be allotted to the sliding rod above it. (5) Solid sliding rod. This
serves as to be an extension as force multiplier for the user to do the task
with minimal force and in a standing posture. (6) Is the handle, the handle
will be 3 inch due to the palm width that is common with most of the people.
The diameter will be 1 inch. This diameter is within the recommended
diameter of the handles based on Dreyfus and Drury said in their study about
handles.
Figure14. Summary of design (PARTS)
References
Lucy, P. C. (2002). U.S. Patent No. 6,343,532. Washington, DC: U.S. Patent and Trademark
reinalt . (2015, jan 1). www.discountire.com. Retrieved march 16, 2016, from
www.discountire.com:
http://www.discounttire.com/infoCenter/infoWheelTorque.html
Teraoke, T.1979. Posture effects on grip strength.Archv. phys. med. rehab.,
78: 154-1156.
Berg, B.L. 2001, Qualitative research methods for the social sciences, Allyn &
Bacon Publishers, Boston, Massachusetts, USA.
Dreyfus, H. (1972), Symbol Sourcebook, McGraw Hill, New York. Drury,
C.G. (1980),' Handles for manual material handling' , Applied
Ergonomics, 11.1, 35-42.
Smith, T , S Smith, M Martin, R Henry, S Weeks, and A Bryant. Grip
strength in Relation to overall strength and Functional Capacity in very
old and oldest old females. The Haworth Press inc. (2006) pp 63-78.
lug wrench. (n.d.) Collins English Dictionary – Complete and
Unabridged, 12th Edition 2014. (1991, 1994, 1998, 2000, 2003, 2006,
2007, 2009, 2011, 2014). Retrieved March 25 2016 from
http://www.thefreedictionary.com/lug+wrench
lozada, B. (april 25, 2014). Filipinos 2nd shortes at South east asia. visited
march 22, 2016, http://globalnation.inquirer.net/102688/filipinos-secondshortest-in-southeast-asia
Aying, Abjie S ; Batuto, Marson Renzel C ; Ochea, Eden S
ABSTRACT
Unlocking lug nuts with initial axial tension present in it
provides a problem especially in users that are not physically fit
as others. Common tool that is used to handle such problem is
either a cross wrench or an L-type wrench which offers minimal
length that will serve as a force multiplier applied. In designing,
Human centered approach was used in order for the users to
have a lug wrench that is efficient yet safe and ergonomic. The
design includes a sliding/adjustable handle that is longer than
usual thus making the task in standing posture rather than
sitting. Minimum dimension of the tool was calculated and
simulated through NX 6 to see critical areas that needs changes.
1. INTRODUCTION
Owning a car, it is important to have the necessary tools in performing
basic maintenance operations. One of the problems in changing tires is
achieving the initial axial tension force needed in loosening the nut by the
use of a lug wrench. Existing designs uses longer handles to address this
problem but longer handles turns to be a hindrance in fully loosening the nut
due to its length. This paper intends to design a tool (lug wrench) that
requires minimal effort from the user and to lessen the time in
loosening/tightening of a Nut.
As old as problem existed, many tools
are invented. One of the new patented to handle such problem to loosen
and tighten a nut of a car tire is A cross-bar socket wrench with a rotatable
gripping handle at one end and a socket-engaging tip at the other. The said
tool was to effectively elongate the working disposition of the device and to
assist in retention during high torque operation (Lucy, 2002). While there are
innovations in performing the task, The L-type and the cross wrench are still
commonly used. The L-type wrench uses longer handles as force multiplier
while the traditional cross wrench has shorter handle compared to an L-type
wrench but has more sizes of bolts that it can loosen (Collins, 2014).
From the current lug wrench tools that is mentioned above, the
common thing is that it focuses only on one aspect of the work which is
either achieving the initial axial tension force needed to loosen the nut or
only to loosen it faster when the nuts are already loosened and simple
turning of the nuts with less force is needed. The gaps of the existing design
is important especially for car users which is not physically fit as others
which needs a tool that will do the task faster and by only using single tool
for both on applying the force needed and faster loosening of the nut.
With the following concepts and considerations, a tool was intended to
be designed. Human centered approach was used to make a design that
aims to make a lug wrench that will maximize the capacity of the material to
be used at the same time making it safe and ergonomic. The design is also
envisioned to simultaneously use only a single tool that can do the task of
achieving the initial axial tension force needed and eliminate the hindrance
of using longer handles in fully getting the nut out of the rim.
2.
LITERATURE REVIEW
2.1 Standards for car wheels installation for bolts/lug nuts
Lug nut is an essential part of a wheel. it is usually made of alloy steels,
aluminum and even titanium. The main purpose of a lug nut is to attach the
wheel to the axle of a car. In order to perform efficiently, it requires proper
torque which is given by the manufacturer. Commonly, car manufacturer
requires 80-100 lb-ft of torque. Failure to acquire these standards may result
to in efficiency, damage to the wheel and car (reinalt , 2015).
Model
Year
Torque requirement
Ford
Aspire
1994-97
85 ft-lbs
Contour
1994-97
85 ft-lbs
Probe
1989-97
85 ft-lbs
All other models
Honda ( all models)
1984-99
1984-04
100 ft-lbs
80 ft-lbs
Hyundai ( all models)
1986-05
80 ft-lbs
1996-00
175 ft-lbs
Chevrolet / GMC
C30 HD (DRW) 5/8-18
Silverado/Sierra HD(DRW)
5/8-18
175 ft-lbs
1999-05
Table 1. car manufacturers standard torque requirement in wheels
2.2 Current Practice, Body Strains, Posture.
Current practice in changing tires involves using hydraulic jack to partially lift
the car, chock (Fig2.2.1) to secure the vehicle from moving forward or backward
before using a wrench in loosening the lug nut. Lastly, the tires will be changed
by new ones and the lug nuts wheel be screwed back again to connect the wheel
to the axle of the car. All of this operation is being done simultaneously in a
sitting posture (fig2.2.2)
2.3 Handle/ Grips
Fig 1. (Choking of wheel)
changing tires
Fig 2. Common posture in
2.3 Grips/ handles
The handle of a tool is necessary in performance of the operation. It serves as the
point of input force by the user to perform the intended work. According to Drury
that said for maximum strength to be applied to the handle and for it to be more
ergonomic, the diameter of it should at least be 3-4 cm (1.1"-1.57") (Dreyfus, H
1972 and Drury, C.G 1980). Grip strength on the other hand will be the basis on
how does or how well the user will hold properly the handle as well as the work
piece. It is also been find out that greatest grip is experienced in the standing
position (Teraoka, 1979). Grip strength was moderately correlated. With overall
body strength in every old and oldest population (Smith, T et al).
2.4 Existing Design
A lug wrench was invented a long time ago; one of the earliest patents was
published by Falk Charles R. in the year 1959. Since then, many innovations have
been made to handle such problem of loosening /tightening a lug nut. commonly,
car owners uses a cross wrench (Fig 3) or an L-type (Fig 4) while some uses new
innovations such as Pneumatic torque wrench (Fig 5) which is an electric
pneumatic wrench with interchangeable tool head attachments, used for
installing and removing nuts (thesaurus.com) next would be a Ratchet wrench
(Fig 6) this tool has a mechanism that consist a bar or a wheel having inclined
teeth into which a pawl drops so that the motion be imparted to the bar only be in
one direction or rotation.
Fig 3. Cross wrench
Fig 4. L-Type Wrench
Fig 5. Pneumatic torque wrench
Wrench
Fig 6. Ratchet
3. DESIGN AND METHODOLOGY
The design of the lug wrench was focused to achieve a human centered tool
that will enable the intended users to perform the task efficiently and safely.
It is an approach to design and develop something that aims to make things
more usable and ergonomic. Sometimes human centered approach tries to
go extra mile and seek new factors like psychology and sociology just to
satisfy users (berg 2001). In getting the dimensions needed for the
adjustable lug wrench, the first step was to get the necessary factors that
will be the basis of the design. These factors are torque requirement, safe
pushing/pulling force of a user, and the material to be used. When
information is gathered, the length and thickness of the material to be used
was calculated by the use of Bending stress and torsional stress formulas.
Lastly, calculated dimension was simulated through Nastran NX6 to see
critical parts that needs minor modification.
4. DESIGN CALCULATIONS
Seen below is the design of a lug wrench that is longer than usual since it will
be used in a STANDING posture. Fig 4.1 is the position in unlocking the nut
from its initial tension. When initial tension is already eliminated, the lug
wrench (fig 4.2) will be adjusted in terms the angle of the Part B. This setup
will allow users to fully loosen a nut while standing with the use of universal
joint connected between part A and B. To better understand the new
dimensions of the wrench, a wheel and average Filipino men having 5’ 3.7”
height(lozada, 2014)was used.
B=3.45
feet
Should
er
level
Elbo
w
level
Figure 4.A Unlocking from initial tension
loosening the nut
Figure 4.B fully
Figure 4.C Kinematic analysis of 4A
analysis of 4B
Figure 4.D Kinematic
Materials: ASISI 148-58 (Sys=60 ksi)
Safe Force to be exerted by the user = 50.6 lbs
( CCOHS, 2009)
Torque requirement (based on table) for SUV & minivans
=175 lb-ft = 2100 lb-in.
Chevrolet(Silverado)
Factor of safety = Nsy 1.5 ( for universal joint = 4 )
Table2. Variables to be used to find the dimensions
For solving the length of B:
The first step is to calculate the length of B as this serves as the force
multiplier to loosen the nut. (The initial tension used in the equation
was
Figure5.
Parts of the
based on torque requirement of Chevrolet Silverado having 175Wrench
lb-ft since it
has the biggest torque requirement among private cars)
Torque = Force x Distance
where: distance is the length of B
T=FxL
L=
T
F
175 lb−ft
= 50.6 lbs
=3.458 ft
For solving the inner diameter (di) of part "A"
Part A of the Wrench is analyzed to have a combination stress. The two
stresses are torsional stress bending stress. With these two stresses, Inner
diameter was calculated to be 0.919inch.
Sds
Nsy
=Sb +Ts
Assumed dimensions:
outer diameter = 1 in
Sds
Mc
Tr
+ J
Nsy =
I
Where:
The cross
sectional area is hollow
cylindrical and the factor of
∴ di=0.919587 in.
safety is 1.5
Figure6. FBD of part A
For solving the inner of diameter of
B1
The hollow cylindrical tube used in part B is analyzed to have bending and
torsional stress. With the two stresses, Inner diameter at a minimum was
calculated to be 0.9881 inch.
Sds
Nsy
=Sb +Ts
outer
diameter = 1.125 in
Sds
Nsy
Mc
I
+
∴ di=0.9881
in.
=
Tr
J
Figure7. FBD of part B (hollow)
For solving the diameter of
B2
(solid part of B for the adjustable handle)
The same from the hollow cylindrical tube in part B, this part still experiences
same type of stress. The only different is that this part is solid. After
calculating, a diameter of 0.7898 inch was found.
Sds
outer diameter = 1.125 in
Nsy =Sb +Ts
Where: The cross sectional area is solid, C =
D
2
Sds
Nsy
,I=
=
πD
64
Mc
I
4
+
Tr
J
∴ di=0.7898
in.
For solving the diameter of universal joint
The universal joint consists of 4 connecting point. A special material of
chrome steel was used. This material has yield strength of 295000 psi. Two
calculate its diameter, the figure from a cross bearing was transferred into a
single cantilever beam type (Figure8). With this, simple bending stress
formula was used thus attaining a diameter of 0.4169inch
0.5”
Figure8. FBD of universal joint
Sds
Nsy
D
where: C = 2
=Sb
,I=
π D4
64
, Sb =295000 psi
, Nsy = 4
Sds
Nsy
=
Mc
I
∴ D=0.41699
in.
For solving the thickness of the YOKE
From the torque requirement based on table 2, a force was applied in the
length of the yoke which is .75 inch. With that, a force of 2800 was
calculated. To simplify the part, it is analyzed like a cantilever beam (Fig9.)
and a force of 1400 was applied since there are two supports in a yoke.
Lastly, it was calculated through bending stress and the thickness of
0.1448inch is the result.
Figure9. FBD of the Yoke
Sb =
Mc
I
Sb rectangle =
b h2
6
Where
Yield strength =Sb=295000psi
0.75inch(t 2)
295000 =
6
∴t=0.1448
in.
Stress analysis.
Seen below is the Stress analysis of the Yoke and universal joint. From figure
10, it is observed that the max stress experienced by the yoke is not near
the design stress. The difference in two values was just taken as a factor of
safety. From figure 11, the design stress was near the max stress
experienced given by NX6. It is due to minor modification done to improve
the diameter of the cross bearing from .0417inch to 0.5169inches at the
critical area near the four corners of the bearing. With the simulated parts, it
is safe to expect that the following dimension of the two parts will handle the
stresses along the operation of loosening a nut.
Figure10. Yoke stress analysis
Joint Stress analysis
Figure11. Universal
Stress analysis.
From figure 12, it is seen that the max stress (33650 psi) was near the design
stress 0f 40000 pounds per square inch. It is also seen in figure 13 to have a
max stress of 43000 psi. Observing from the two figures, it is evident that
the critical parts are those that are connected to the universal joint rather
than the input point which is the handle. From the results in the simulation, it
assures that the following dimension was calculated correctly thus making
the part uses minimal material possible and performs the task without
breaking the material given the results and the factor of safety being done.
Lastly, parts can still be maximized. Looking at Figure 12, it is seen that the
solid part used for sliding the handle experiences little stress compared to
the other parts. With that observation, it is possible to taper the part which
only experiences a stress ranging from 1040 psi-7560psi.
Figure12. Universal joint stress analysis
Part A stress analysis
Figure13.
5. SUMMARY OF DESIGN
The adjustable lug wrench is divided into parts. (1) Is the part that secures
the tool to the wheel. It locks the two parts (Lug nut and wrench) in order for
the lug nut to be loosened. (2) Is a Yoke. This part is connected to the
universal joint to transmit rotation from B to A. (3) is a universal Joint. This
specific part allows motion or rotation from one distinct body to another at
an angle. (4) Is a hollow cylindrical tube. This part is intended to be hollow
for storage purposes due to the length of the wrench. The space inside the
cylinder will be allotted to the sliding rod above it. (5) Solid sliding rod. This
serves as to be an extension as force multiplier for the user to do the task
with minimal force and in a standing posture. (6) Is the handle, the handle
will be 3 inch due to the palm width that is common with most of the people.
The diameter will be 1 inch. This diameter is within the recommended
diameter of the handles based on Dreyfus and Drury said in their study about
handles.
Figure14. Summary of design (PARTS)
References
Lucy, P. C. (2002). U.S. Patent No. 6,343,532. Washington, DC: U.S. Patent and Trademark
reinalt . (2015, jan 1). www.discountire.com. Retrieved march 16, 2016, from
www.discountire.com:
http://www.discounttire.com/infoCenter/infoWheelTorque.html
Teraoke, T.1979. Posture effects on grip strength.Archv. phys. med. rehab.,
78: 154-1156.
Berg, B.L. 2001, Qualitative research methods for the social sciences, Allyn &
Bacon Publishers, Boston, Massachusetts, USA.
Dreyfus, H. (1972), Symbol Sourcebook, McGraw Hill, New York. Drury,
C.G. (1980),' Handles for manual material handling' , Applied
Ergonomics, 11.1, 35-42.
Smith, T , S Smith, M Martin, R Henry, S Weeks, and A Bryant. Grip
strength in Relation to overall strength and Functional Capacity in very
old and oldest old females. The Haworth Press inc. (2006) pp 63-78.
lug wrench. (n.d.) Collins English Dictionary – Complete and
Unabridged, 12th Edition 2014. (1991, 1994, 1998, 2000, 2003, 2006,
2007, 2009, 2011, 2014). Retrieved March 25 2016 from
http://www.thefreedictionary.com/lug+wrench
lozada, B. (april 25, 2014). Filipinos 2nd shortes at South east asia. visited
march 22, 2016, http://globalnation.inquirer.net/102688/filipinos-secondshortest-in-southeast-asia
