This document discusses the design of a manually and automatically operated screw jack that can lift up to 3 tonnes. It aims to design a lightweight screw jack. The jack can be operated easily by all without consideration of age or gender. It has both manual and automatic options to allow operation in situations where power is not available. The key components are a screw, bearings, gears, frames, and nut. Materials and dimensions are selected to support the 3 tonne load safely with a factor of safety of 5. Motion, stress, displacement, and strain analyses are performed to validate the design.

1. DESIGNING OF A MANUALLY & AUTOMATIC
OPERATED SCREW JACK
In this current presentation we are going to discuss the design a screw jack which can be operated
manually and automatic as well.
Our main goal to achieve is, to design a light weight screw jack which can uplift a Weight upto 3
tonnes.
Why we considered it to be lightweight &automatic?
The jack could be operated easily without AGE & GENDER consideration.
Why the need of adding manual option?
The difficulty in providing a power source at each circumstances let us to add the manual option
Innovation: Automatic(era) & Internal and External threaded Screw

2. SCREW JACK
A screw jack is a portable device consisting of a screw
mechanism used to raise or lower the load.
Principle: The screw jack works is similar to that of an inclined plane.
Dc working principle: d.c motor is coupled with the screw jack by gear arrangement.
The screw jack shaft‟s rotation depends upon the rotation of D.C motor.
The D.Cmotor shaft is connected to the spur gear. If power is given to the D.C motor,
it will run so that the spur gear also runs to slow down the speed of the D.C motor.
Types of jacks-
A hydraulic jack consists of a cylinder and piston mechanism. The movement of the
piston rod is used to raise or lower the load. Mechanical jacks can be either hand
operated or power driven.
Screw jack
Mechanical
Scissor Jacks
Bottle Jacks
Hydraulic

3. MATERIAL PROPERTIES
S. NO. PARTS MATERIAL SPECIFICATION
1) Screw Plain carbon steel 30C8
Syt =400MPa Sut
=550MPa
d=36mm dc=30mm p=6mm
2) Bearing Chrome stainless steel
Syt =300MPa Sut
=445MPa
ISO104-113352
3) Gear AISI 4340 normalised
steel
t=12 module=2.5 T=50
4) Lower Frame Hard cast steel
5) Upper Frame Syt =485MPa Sut
=275MPa
ASTM A27 grade 70

4. SCREW
Plain carbon steel 30C8 Syt =400MPa Sut =550MPa
Single threaded screw(l=p)
load=W=3 tonnes=3000*9.8=2940 N
Factor of safety=5
Calculation= Syt =
𝑊∗𝑓
𝑝𝑖∗𝑑𝑐2
dc=21.63mm≈30mm(after allowance)
let p=6mm
d=nominal diameter=dc+p=36mm
dm=mean diameter=
𝑑+𝑑𝑐
2
=33mm
µ=0.149 ϕ=tan-1µ
α=tan-1(
𝑝
𝑝𝑖∗𝑑𝑚
) α=3.31 deg
Self locking
ϕ>µ i.e 8.5 deg >3.31deg
Torque subjected to screw Mt=
𝑊∗𝑑𝑚∗tan(α+µ)
2
=101431.03 Nmm
Shear stress ¢=
𝑝
𝑝𝑖∗𝑑 𝑐
3=19.13Nmm-2
Ϭ(sigma)=
𝑊
𝑝𝑖∗𝑑𝑐2=41.59 Nmm-2
Fs=syt/sigmac=400/41059=9.61

5. l=length of screw l=130mm P=effort=250N
Mb=250*130=32500 Nmm
Sigmab=bending stress associated with bending moment
Sigmab=32Mb/(pi*dc
3=12.26 Nmm-2
ζmax=
𝜎 𝑏
2
2
+ 𝑇2=
12.2𝜎
2
2
+ 19.13 2=20.18Nmm-2
𝑓𝑠 =
0.5∗ 400
ζmax
=10
Buckling consideration
L=300mm 𝑘 =
𝑇
𝐴
=dc/4=7.5
Slenderness ratio=l/k
For given situation
l/k=130/7.5=17.33
E=207000Nmm-2
𝑝𝑐𝑟 = 𝑆 𝑔 ∗
𝜋
4
∗ 30*30*(1 −
400𝑥 17.33 2
4𝑥
1
4
𝑥𝜋2 𝑥 207000
)=266117.6N
Fs=Pcr/W=266117.6/29400=9

6. DESIGNING OF NUT
For the material of nut
ASTM A27 grade 70-40
Sb=permissible bearing pressure
Sb=10Nmm-2
z=no. of thread required
z=
4∗𝑊
𝜋𝑠 𝑏 𝑑2−𝑑 𝑐
2 =9.45
H=z*p=60mm
ζn=
𝑤
𝜋𝑑𝑡𝑍
=8.66Nmm-2
𝑓𝑠 =
𝑠 𝑠𝑦
𝜏 𝑛
=200/8.66=23.08

7. SPECIFICATION
OF BEARING
SPECIFICATION
OF GEAR
Ball Bearing(axial-loading)
Chrome stainless steel
Syt =300MPa Sut =445MPa
Total height=12.5mm
Internal dia=36mm
External di=50mm
Spur gear-Trapezoidal profile
Total no. of teeth=46
Addendum dia=115mm
Clearance=1mm
Dedundum dia=105mm

8. HANDLE
Mt=1014314.03Nmm
p=effort=250N
Mt=p*lh
1014314.03=250*lh
lh=405mm
𝜎 𝑏=
32𝑀𝑡
𝜋𝑑ℎ
3
400
5
=
32 × 101431.03
𝜋𝑑ℎ
3
dh=23.46≈24mm

9. ANALYSIS OF BEARING
Chrome stainless steel
Syt =300MPa Sut =445MPa
Total height=12.5mm
Internal dia=36mm
External di=50mm
Maximum compressive allowable stress on bearing=
𝑊
Π
4
∗(502−362)
=31.09Nmm-2
fs=
300
31.09
=9.64≈10

10. POWER CALCULATION FOR AUTOMATIC
Let N be the rpm of the nut containing gear
N=15rpm(consider)
𝜔 = 1.57𝑟𝑎𝑑/𝑠𝑒𝑐
P= 𝜔*Mt
P=1.57*101431.03*10-3watt
P=159.2watt
Neglecting collar friction as well as moment associated with it

11. PARTSOF THE LIFTINGJACKIN EXPLODEDVIEW

12. MOTIONANALYSISOFTHELIFTINGJACK

13. MAGNITUDEOFSTRESSESINDUCED

14. DISPLACEMENTOFDIFFERENTPARTS

15. EQUIVALENTSTRAIN

16. UNDER THE GUIDANCE OF
DR KALYAN KUMAR SINGH
GROUP MEMBERS
• Abhishek Kumar 15JE001459
• Akshay Mandwale 15JE000968
• Sachin Kumar 15JE001463
• K Bharat Kumar 15JE001160
• Raghvendra Singh 15JE001431