Paval Marius Catalin IMEN 1531: An Example of Peculiar Press Structure: Shop Press

Paval Marius Catalin
IMEN 1531
PROJECT
I. Design and analysis of a press mechanism
For the given press mechanism nr :2
The length of the links are: Crank r=60, Coupler l=220
Design the mechanism for Slider displacement of h=80.
1. Make a through investigation of the press mechanisms
Press
A forming press, commonly shortened to press, is a machine tool that changes the shape of a
workpiece by the application of pressure.[1] Presses can be classified according to
 their mechanism: hydraulic, mechanical, pneumatic;

 their function: forging presses, stamping presses, press
brakes, punch press, etc.
 their structure, e.g. Knuckle-joint press, screw press
 their controllability: conventional vs. servo-presses
An example of peculiar press structure:

shop press
A simple frame, fabricated from steel, containing a bottle jack or simple
hydraulic cylinder. Good for general-purpose work in the auto mechanic
shop, machine shop, garage or basement shops, etc. Typically 1 to 30 tons of pressure, depending
on size and expense. Classed with engine hoists and engine stands in many tool catalogs.
Some examples of presses by application
1
 A press brake is a special type of machine press that bends sheet metal into shape. A good
example of the type of work a press brake can do is the backplate of a computer case. Other
examples include brackets, frame pieces and electronic enclosures just to name a few. Some
press brakes have CNC controls and can form parts with accuracy to a fraction of a millimetre.
Bending forces can range up to 3,000 tons.[2][3][4]
 A punch press is used to form holes.
 A screw press is also known as a fly press.
 A stamping press is a machine press used to shape or cut metal by deforming it with a die. It
generally consists of a press frame, a bolster plate, and a ram.[5]
 Capping presses form caps from rolls of aluminium foil at up to 660 per minute.
2. Make the structural representation

.
2
3. Identify links and pair, kinematic groups, loops, compute DOF.
A: R1-2 f=1;
B: R2-3 f=1;
C: R3-4 f=1;
D: R3-5 f=1;
E: R1-4 f=1;
F: R5-6 f=1;
G: T1-6 f=1;
DOF=3(4-1)-2*4=1
4. Propose a first kinematic analysis and choose the appropriate length of the
links.
AB=60;
BC=220;
CE=100;
AE=230;
CF=230;
AB+AE<BC+CE
5. Perform a first kinematic analysis by the graphical method. Extract

numerical results and discuss those using tables and curves you may find
appropriate.
F2 -40 20 80 140 200 260 320

F4 14 45 54 31 -4 -19 14
S -138 -114 -112 -121 -166 -197 -138
3
4
6. Write and solve the loop closure equation. Present numerical results for 6
positions of crank.
i) AB+BC+CE+EA=0
AB=l2u2=l2(icosF2+jsinF2)
BC=l3u3=l3(icosF3+jsinF3)
CE=l4u4=l4(icosF4+jsinF4)
EA=l1u1=l1(icosF1+jsinF1)
ii)
CE+EF+FC =0
CE= l4u4=l4(icosF4+jsinF4)
EF=l5u5=l5(icosF5+jsinF5)
FC=l6u6=l6(icosF6+jsinF6)
5
AB+BC+CE+EA=0
l2u2+l3u3+l4u4+l1u1=0
l2(icosF2+jsinF2)+l3(icosF3+jsinF3)+l4(icosF4+jsinF4)+l1(icosF1+jsinF1)=0
-l4(icosF4+jsinF4)=l2(icosF2+jsinF2)+l3(icosF3+jsinF3)+l1(icosF1+jsinF1)/2
l42=l22 +l32+l12+2l2l3(cosF2cosF3+sinF2sinF3)+2l2l1(cosF2cosF1+sinF2sinF1)+
+2l3l1(cosF3cosF1+sinF3sinF1)
A=2l2l3sinF2+2l3l1sinF1
B=2l2l3cosF2+2l3l1cosF1
C=l22+l32+l12+2l2l1(cosF2cosF1+sinF2sinF1)-l42
−𝐴−√𝐴2 +𝐵2 −𝐶 2
F3=2atan( )
𝐵−𝐶
F3=130.53°
l32=l22+l42+l12+2l2l4(cosF2cosF4+sinF2sinF4)+2l2l1(cosF2cosF1+sinF2sinF1)+
+l4l1(cosF4cosF1+sinF4sinF1)
A=2l2l4sinF2+2l4l1sinF1
B=2l2l4cosF2+2l4l1cosF1
C= l22+l42+l12-l32+2l2l1(cosF2cosF1+sinF2sinF1)
−𝐴−√𝐴2 +𝐵2 −𝐶 2
F4=2atan( ) F4=14°
𝐵−𝐶
CE+EF+FC =0
l6u6+l4u4+l5u5 =0
l6(icosF6+jsinF6)+l4(icosF4+jsinF4)-l5’i-sj=0
-l6(icosF6+jsinF6)=l4(icosF4+jsinF4)- l5’i-sj/2
L62=l42+l5’2+s2 -2l4l5’sinF4-2l4scosF4
A=1
B=-2l4sinF4
C= l42+l5’2 -l62-2l4l5’cosF4
D=B2-4AC
−𝐵±√𝐷
s= 2𝐴
s=138.4025
F3C 130.53 125.24 108.49 100.31 101.38 112.50

F4C 14.0236 45.1113 53.5684 31.4131 -3.5504 -18.865
SC -138.40 -114.49 -112.60 -121.40 -165.99 -197.32
6
7
7. Choose the proper dimensions to obtain the imposed slider displacement.
For finding of the length h we must

firstly to find the minimum and
maximum position of the
mechanism after this, we must
measure the length between them.
Through changing of slope
inclination of base we obtain the
final h the imposed one.
We will approximate the length

h=287.5829 to h=280
8. Conclusions, final dimensions and

recommendations for the detailed
design.
8
In this last figure we can observe that the value of h is the imposed one.
A recommendation for finding the length of h is to draw two circles: one
from the point of minimum position of the slider with the radius h and the
another one with radius equal with the length of the final segment by the
slider from the last articulation (in this case in point E with length 130).
9
II. Design and analysis of a gear train with gear pair and a
planetary gear with a gear ratio of 13+n/3
14
𝑖 = 13 + = 17.66
3
10
1. Choose the appropriate type the gear train.
2. Choose the number of teeth and module
11
z3 = z1 + 2 ∙ z2
z1 = 19
z2 = 21
z3 = 19 + 2 ∙ 21 = 61
61 z5
17.66 = (1 + )∙( )
19 z4
z5 1
= 17.66 ∙ = 4.19
z4 4.21
z5 = 4.19 ∙ z4
If z4 = 19
→ z5 = 79.61
3. Compute the gear ratio.

ω1 ω1 ωh ω4 ω1 ω4 z3 z5
i= = ∙ ∙ = ∙ = (1 + ) ∙ ( )
ω5 ω h ω 4 ω 5 ω h ω 5 z1 z4
61 80
i = (1 + )∙ = 17.72
19 19
12
4. Compute the gears’ geometry.
We adopt the module [mm] from STAS 822-82:
m=1.25
We calculate the geometric elements of gear wheels :
-the height of tooth:
13
-The head of tooth:
-The foot of tooth:
-Head circle:
-Foot circle:
-Base circle:
-Rolling circle / division:
Number of Number
Modulus h ha hf da df db d
gear of teeth
1 19 3,125 1,25 1,5625 26.25 20,625 22,3177 23,75
2 21 3,125 1,25 1,5625 28.75 23.125 24.6669 26.25
1,25 3 61 3,125 1,25 1,5625 78.75 73.125 71.6515 76.25
4 19 3,125 1,25 1,5625 26.25 20,625 22,3177 23,75
5 80 3,125 1,25 1,5625 102.5 96.875 93.9692 100
14

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Paval Marius Catalin

1. Make a through investigation of the press mechanisms

 their mechanism: hydraulic, mechanical, pneumatic;

An example of peculiar press structure:

Some examples of presses by application

2. Make the structural representation

5. Perform a first kinematic analysis by the graphical method. Extract

F2 -40 20 80 140 200 260 320

F3C 130.53 125.24 108.49 100.31 101.38 112.50

For finding of the length h we must

We will approximate the length

8. Conclusions, final dimensions and

2. Choose the number of teeth and module

3. Compute the gear ratio.

We adopt the module [mm] from STAS 822-82:

-The foot of tooth:

-Rolling circle / division:

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