Stair climbing trolley is an extension of general trolleys. These are used to transport loads on stairs and uneven surfaces like holes, speed breakers etc. It is operated by a single operator and with less effort.

1. Design Thinking
Project
Under the guidelines of
Dr. K. KRISHNA
BHASKAR
Stair Climbing Trolly
P Santosh Kumar (19021A0328)
S Mohan Sainath (19021A0330)
M Bharathi (20025A0355)

2. Introduction
 A hand trolley is a small
transport device used to move
heavy loads from one place to
another.
 It is a very common tool used by
a large number of industries that
transport physical products. Also
called a hand truck or a dolly.
 Often used by stock persons who
arrange and restock merchandise
in retail stores. Types of trolleys

3. Stair Climbing
Trolly
Stair climbing trolley is an
extension of general
trolleys. These are used to
transport loads on stairs and
uneven surfaces like holes,
speed breakers etc. It is
operated by a single
operator and with less
effort.

4. Working of Stair
Climbing Trolly
 It consists of three wheels at
three corners of an equilateral
triangle while moving on flat
surfaces two wheels on either
side will slide on ground.
 Because of two wheels on
either side will slide, it can
carry more loads compared to
conventional trolleys.

5. While, climbing stairs
each wheel with respect
to center of triangle gets
rolled.
Control of this trolley is
made easier by using a
flexible handle. Load is
carried out which is
supported by a iron
frame.
Working of tri star wheel

6. Isometric view Side view Top view
DESIGN AND ANALYSIS

7. Tri-Star wheel
Mechanism
The wheels are arranged in
a triangular array such that
centres of each of the
wheels coincide with the
vertices of an equilateral
triangle. Now the side of
an equilateral triangle (R)
and radius of the wheel (r). Formation of Tri-Star wheel

8. Radius of Tri
Star
𝑅 =
𝑎2 + 𝑏2
3
Where, R is the radius of tri
star.
Radius of Tri Star

9. Radius of the Wheel
The minimum radius of regular wheel (𝑟𝑚𝑖𝑛) is expressed as
𝑟𝑚𝑖𝑛 =
6𝑅𝑡 + 𝑎 3𝑏 − 3𝑎
3 − 3 𝑎 + 3 − 3 𝑏
The maximum radius of regular wheel (𝑟𝑚𝑎𝑥) to prevent collision of the wheels
together is expressed as
𝑟𝑚𝑎𝑥 =
𝑎2 + 𝑏2
3

10. Force Necessary to
Pull the Trolly
F. 𝑥 = 𝑊. 𝑦
𝐹 =
𝑦
𝑥
. 𝑊
Maximum load determination

11. Analysis of Axle Load
The bending stress of the axle can be calculated by using the bending equation
𝑀
𝐼
=
𝜎
𝑦
=
𝐸
𝑅
∴
𝑀
𝐼
=
𝜎
𝑦
𝜎 =
𝑀
𝐼
× 𝑦

12. Machining Process
Cutting The cutting technique used for extra metal removal.
Welding The frame of the trolly is formed through the welding process.
Drilling Drilling used to drill the holes at the tri star frame.
Pipe Bending Pipe bending is used to bent the pipes at varying angles.
Machining process involves

13. Cost of
Estimation of The
Project
S. No Item Rate Quantity Price (₹)
1 Rubber Wheels
(OD=150mm)
250 each 6 pcs 1500
2 Ball Bearing
(Deep groove)
60 each 4 pcs 240
3 S.S. grade304
(250mmx900mm)
200/kg 3.5kg 700
4 M.S. hollow pipe
(OD=30, ID=26)
- 4m long 200
5 Pipe Bending Costs
(Handle Pipes)
20 each 2 40
6 M.S. plate
(300mmx400mm)
55/kg 1.7kg 90
7 Pipe and plate cutting costs 10 per cut 15 150
8 Plasma arc Cutting 50 each 4 200
9 M.S. L angle - 1 120
10 Material for Shaft & Bearing housings - - 170
11 Turning & Facing for Bearings
housings & shaft
- - 350
12 Washer and Cotter pin - - 20
13 Welding and Finishing costs - - 1120
4900/-
Material selection may be a
step within the process of
designing any object. In the
context of product design,
the goal of material
selection is to attenuate the
cost while meeting product
performance goals.

14. Fabrication
Since, for the fabrication different machining processes are required
which are becoming difficult in the current situation. Therefore, the
fabrication of the model is not done yet but design analysis and
estimated cost of the model is done.

15. Thank You