This document presents the design of a universal door position device for a heavy duty portal carriage and wagon wheel lathe. The device uses electronic circuits and sensors to ensure the lathe door is closed before cutting operations begin for safety. It describes the existing unsafe conditions, proposed safety system components like input sensors, logic circuits, output signals and a buzzer, and applications for the design in improving lathe safety and preventing injuries. PCB design and circuit diagrams are provided, along with potential other uses of similar safety systems.

1. By: Thobekile Ndabeni
Supervisor : V.S. Malaza
Transnet Engineering
coordinator : Mr. PR Tjale
Cape Peninsula University of Technology
13 October 2014
Heavy Duty Portal Carriage and Wagon
Wheel Lathe
Universal Door Position device of a :
Practical Training 2 Technical presentation

2.  Introduction
 Purpose of Presentation
 Unsafe Environment
 Portal after Operation
 Injuries associated with the Lathe machine
 Standard Operating Procedure
 System flow diagram
 Logic circuit
 Main switch /Start Button (Input signal)
 Door switch (Input signal)
 Timer circuit
 Protection Device
 Voltage rectification
 DC Voltage regulation
 Output signal LED lights(Output signals)
 Buzzer
 Complete Circuit Diagram
 PCB Design
 Other uses
 Motion and Light sensitive switches
 Conclusion
 References
 Questions?
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Topics to be discussed

3.  One of the important factors we always discuss is the
safety factor .It is very important to invests to safety
devices as they may help to save lives, loss of limbs,
eye sight , hearing and money.
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Introduction

4.  To provide safer working environment
 To introduce effective methods using safety electronic devices.
 To develop standard, policies, procedures and guidelines for the
implementation of Safety management systems.
 To motivate investment in Safety training and on-going awareness for
all employees , contractors and visitors.
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Purpose of the design

5.  The Machine was Manufactured in 1976.
 It lacks the installation of safety devices.
 Under operation small particles that are cut from the wheel, find a way to fly
out of proportion.
 Proper PPE is required for this machine.
 Copying slides are provided which will act as a bearer.
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Unsafe Environment
Pictures Curtsey of Willison & O'Regan 2006)

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Portal after operation

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Injuries associated with the lathe
machine

8. 1. Wheel set to be rolled into the machine.
2. Drivers to be set to the chucking diameter
3. The suitable profile template to be set.
4. All selector switches to be set to “Automatic sequence”.
5. The keys of the keyboard to be actuated according to the figures of the
measuring sheet for diameter and lateral correction.
6. Starting Push Button to the Actuated
The following steps are represented by the flow diagram below.
a) The tool blocks to be positioned (Automatically)
b) The tool block to be laterally positioned(Manually)
c) The copying slides to be traversed
d) The main driving system and the feeder mechanism to be switched on.
e) tool block return to their initial position.
f) The wheel set to be unchecked to be lowered to rest on the rail
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Standard operating Procedures

9. Transnet Rail Engineering ,a Business Unit of Transnet Limited 9
System Flow Diagram Start
Machine
ON?
Green Light
ON
copying
slides
Closed?
Orange Light
ON
Start
Cutting?
Red Light ON
END
Green Light ON
Start
Cutting?
Flashing Red Light ON
YES
YES
YES
NO
NO
NO
NO
YES
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10.  LOGIC TABLE
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Logic Circuit Design
INPUTS OUTPUTS
Slides Machine Cutting G R O FR
0 0 0 0 0 0 0
0 0 1 0 0 0 0
0 1 0 1 0 0 0
0 1 1 0 0 0 1
1 0 0 0 0 0 0
1 0 1 0 0 0 0
1 1 0 0 0 1 0
1 1 1 0 1 0 0
Cont….
 KEYS: INPUTS
slides : Closed =‘1
Machine: ON=‘1’
Cutting : Start =‘1’
Logic ‘1’ = 5 v, Logic ‘0’ = 0 v
 KEYS:OUTPUTS
G-green light signal
R-Red light signal
O-Orange light signal
FR-Flashing Rd light signal

11.  This switch is to switch the device ON/OFF
 STDP switch Is employed
 It is coupled to the Machines Main switch.
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Main switch of the device
Cont….
220Vac
STDP
Switch
Machine
ON/OFF
Device
ON/OFF

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……END
Pictures Curtsey of Composites/Nano Engineering ,2004)

13.  The duty cycle = 75 %.
 Frequency =0.7 Hz
 Vout =9 V
Components Calculations
t1=D*T=0.75*1.33= 1s
t2=T-t1=1.33-1 =0.33s
R2=t2/(0.693*C1)=0.33/(0.693*1µ)=476KΩ
R1=(t1/(0.693*C1))-R2 =(1/(0.693*1µ))- 476K=967KΩ
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Timer Circuit
Cont….

14. Fuse Selection
 Power(heat)Dissipation fuse
 normal operating Current : 2A
 Break Down Current :2.7 A(135% of 2A)
 operating voltage :220-240Vac,50Hz
 Ambient Temperature: -15°C to 30°C
 PCB Considerations : thru-hole mounted
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Protection Device
Pictures Curtsey of Hans & Jos. Kronenberg ,2004)

15. Friday, August 12, 2016Transnet Rail Engineering ,a Business Unit of Transnet Limited 15
Voltage Rectification
……END
 We will utilise the 220Vac.
 Internal power supply
 Follow SABS standards :SANS 10142-1:2008
 Used Full bridge Rectification.
 Rectify 220Vac to14VDC

16.  A 12VDc voltage source is utilized in this entire circuit.
 The voltage is regulated so it provides a fixed output
voltage
 Model RG178L12 ;14VDC to 12VDC (100mA max)
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DC Voltage Regulation
INPUT:14VDc.
From Rectifier
OUTPUT:12VDC(100mA)
To Circuit
Cont….

17.  affordable
 energy saving properties
 Operates at low DC voltages
 Easy to install and maintain
 Has adequate output wattage as per job required.
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Low voltage LED lights
Cont….

18. Friday, August 12, 2016Transnet Rail Engineering ,a Business Unit of Transnet Limited 18
Low voltage LED lights
….END
Pictures Curtsey of Hans & Jos. Kronenberg ,2004)

19.  Operates at a range of 8m in radius
 operates only when the wheels are being cut ,with the
door being opened .
 A 500 ohms pull-up Resistor is employed.
 Ratings: 12Vdc,80Db,20mA
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Buzzer Circuit
Pictures Curtsey of Williams JD, Wahab M, Wang W,2001;Pg102)

20. Friday, August 12, 2016Transnet Rail Engineering ,a Business Unit of Transnet Limited 20
Complete Circuit Diagram

21.  PCB wizard 3
 Physical dimensions: 80x80 mm
 Grid : 0.100 mm grid with 0.060 mm track
 Minimum spacing: 3 mm
 Isolation Gap : 2 mm
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PCB Design
Power Rectification PCB Logic PCB

22.  Car doors
 Industrial and household fridges
 Earth switches
 Automated Lighting systems
 Alarm system
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Other uses

23.  operates at 11 to 16 Vdc
 Range : 0.2m to 3.5m
 Speed:0.18 m/s to 3.4m/s walking speed
 Operating Temperature :-20°C to +50°C
 maximum current consumption 15mA
 Installation Heights: 2.1m to 2.7m
 Output: Relay type 100mA/28Vdc, N.C.
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Motion Sensors
Pictures Curtsey of Williams JD, Wahab M, Wang W,2001;Pg111)

24.  SPECIFICATION
Power source: 220V-240V/AC Power Frequency: 50Hz
Rated Current: 10A Ambient Light: <<5-50LUX(adjustable)
Working Temperature: -20~+40° C Working Humidity: <93%RH
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Light sensitive switches
Pictures Curtsey of Baton Rouge, LA,2001, Pg 99 )

25. The use of safety electronic equipment is of great
essence ,as it maximises the safety aspects and
enforces the implementation of safety operating
procedures in the working environment.
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Conclusion

26.  Subject to technical alterations ,Hans & Jos. Kronenberg GmbH,pge111
 Microstructures: Concepts of Fatigue and Fracture Parameters,” To be presented
at the
 Eleventh International Conference on Composites/Nano Engineering (ICCE-11), Hilton
Head, SC (2004).
 780 Industrial Blvd., St-Eustache (Quebec) J7R 5V3 South Africa
 Williams JD, Wahab M, Wang W, “Fracture Mechanics Aspects of LIGA
 Relays,” Proceedings of the International Symposium on Test and Measurement, 1:
1-9 (2001).
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References

27. Friday, August 12, 2016Transnet Rail Engineering ,a Business Unit of Transnet Limited 27
Questions