Podium Pressure Locking Safety System Richard Cavanagh, Piragash - - PowerPoint PPT Presentation

Podium Pressure Locking Safety System

Richard Cavanagh, Piragash Selvakumar, Ricky Eatough & Mohit Miyanger Queen Elizabeth’s Boys School, Barnet

The Issue

 Working at height is the biggest killer in the construction industry.  In 2016/17, 30 fatal injuries occurred concerning construction.  In 2016/17, 25 fatal injuries occurred relating to working at height.  The main reason for this was that workers were failing to lock their wheels.

The Problem

 When needing to work on ceilings and high walls in a construction project, workers are required to use a podium steps and require the brakes of the podiums to be applied before entering.  Workers fail to lock the wheels due to many psychological factors such as trying to complete as many tasks as possible.  Main Question: Can the human aspect of applying the brakes be removed?

Brief

To design an attachment or alteration to PAS 250 compliant podium steps that:

• Removes the need for workers to apply the brakes consciously
• Should be intrinsic and automatic
• Must require the worker to get off the podium to remove the brakes and to move the

podium again

• Stops podium steps from toppling when wheels/feet are directly over floor boxes
• Stops operatives from skating

Platform Step

PAS 250 Regulated Podium Wheel locking mechanisms

Scissor lift Raised false floor

Research

Two sites visited in Canary Wharf:

• 1. Deutsche Bank Project
• 2. Barclays Bank

Power towers Pecolift PAS 250 1000 Podium unit

• Standards legislation
• Unlocked by deliberate

actions

• Corrosion protection

according to BS 8620

• Percentage elongation after

fracture of load-bearing components

• Materials
• Aluminium
• Mild Steel
• Dimensions of floor boxes

70-130mm (standard 85mm)

Site Visit Questionnaire

Why do injuries occur? How many & How serious are they?

• Podium ‘surfers’ and ‘skaters’ – ‘laziness’.
• Walk off without locking wheels.
• Several serious injuries.

How are workers alerted to the need to lock the wheels? (both groups)

• Safety managers walk round the site.
• Notices at the site informed workers using podiums that ‘brakes to be used at all times when in use’.
• Stabilisers not mandatory – trip hazards.

Variation of working platforms:

• A large variety of platforms were in use such as:
• Delta deck.
• PECO lift - Preferred method
• Locks automatically
• Easy to adjust height
• Large – fitting through doorways
• Heavy – hard to take up stairs
• Expensive
• ECO lift.
• MEWPs (mobile elevating work platforms).
• Scaffold towers.
• Podium steps.
• Standard stepladders.

Product analysis – Kick stool

• Generic kick stool as found in shops:
• 3 Spring loaded castors
• Auto locking handle
• Rubber seal
• Difficult to topple

Specification

• The specification had to be adjusted due to the different types of research, such as the British Standards legislation.
• This can be seen with specification point F3 that requires the worker to manually remove the brakes of the podium

steps.

• The performance section of the specification has been directly influenced by how we saw the podium steps being used

during our site visits to the Clifford Chance and Barclays Bank buildings.

• The ergonomics section has been deduced by using anthropometric data to work out what sizes we needed to make

certain parts of the product in order to make sure they were not uncomfortable for the user or were too small for the user to use.

• The safety of the workers was of the utmost importance when creating the specification as it was the main problem that

arose in the situation.

Conceptual Ideas

Before Pressure Applied After Pressure Applied

Idea 1:

Positive: Easily locks wheels. Negative: Not collapsible, easy to break Can still go through floor boxes. A large block locks the wheel and comes into contact with the ground after the user releases the handle The block is pivoted through attachment to the main frame.

Idea 2:

Positive: Prevents surfing, skating and floor box dangers. Negative: Large and not collapsible.

Conceptual Ideas

Idea 3:

Positive: Prevents surfing as the wheels will lock. Negative: No safety mechanism: Roll in other direction when worker steps off. Weight of operative causes podium to lower. Bar rests on the ground - Large surface area on the ground – prevents toppling.

Idea 4:

Final Idea based off this design Positive: Auto-locks wheels. Floor box fall protection. Negative: Large to carry through doorways and hard to transport.

Spring-loaded mechanism in wheels allow free 360 degree motion. A large surface area on the bottom means that it will not damage the floor and will provide even pressure. A spring loaded mechanism is used in each

• f the four legs which can

be easily attached on and

• ff.

The adaptations can clip on, meaning that it will be easy to transport and carry.

First Development

 Developed from concept 4  Trapezoidal prism for surface area

Positives

 Large surface area  Removeable  Simple

Negatives

 Too much material  Difficult to transport

Two points of contact

The Solution

▶

Developed in UCL

▶

Trapeziums to shrouds

▶

Spring Loaded Wheel Mechanism

▶

Small amount of material used

▶

Lightweight

▶

Can be retrofitted

▶

Intrinsic design

▶

Automatically Locks wheels

▶

Large shroud size

▶

Prevents podium toppling in Gromit & Floor boxes

▶

Pin mechanism

▶

Manageable height

▶

Width right for hands

Complete Mechanism

Mechanism Animations

Close Up Complementary Shapes Close-up

CAD

Outer tube Inner tube Shroud Cap Shroud Main compression spring Variable Spring Tension Crutch Mechanism Two points of contact

Manufacture

1 3 4 5 6 7 8 9 10 2 11

• Testing was carried out on the prototypes we manufactured and not on a full scale working

platform, so the scale of our tests had to be reduced to suit the prototypes.

• The prototypes were assessed via 3 different tests.
• Test 1 : Activation of Brakes. Required 45.5 kg to activate the pin mechanism.
• Test 2 : Deactivation of Brakes.
• Test 3 : Movement of Prototype. 19.8 seconds to walk in a circle with a radius of 2 metres and

was successfully moved 20 metres forward.

• These tests allowed us to find out how well the prototype followed the specification.

Testing

Test 1 Test 2 Test 3

Costing

Prototype Industrial Manufacture

Element Quantity & Dimensions (mm) Component Cost (£) Source Steel tube 50.8 diameter 1.5 thickness 1200 Outer steel tubes 25.91 Steel Tubes Direct Steel rod 10 diameter 1000 Inner rods 5.88 B&Q Steel tube 30 diameter 1.5 thickness 800 Inner steel tubes 14.71 Steel Tubes Direct Foam 50 600 1250 Shroud mould 26.75 4D Model Making Materials Steel spring 5 20 Crutch springs 6.99 Screwfix Steel spring 20 diameter 25 Springs 4.46 Cromwell Sheet steel 3 60 110 Discs 0.66 The Metal Store Aluminium ingot 12.7 1000 Shroud 21.07 Metals4U Sheet steel 240 240 Discs 4.34 The Metal Store Nuts M10 Nuts 0.26 Cromwell Washers M10 Washers 0.46 Tool Station TOTAL

111.49

Element Quantity Dimensions (mm) Component Cost (£) Source Steel rod 4 10 diameter 1000 Inner rods 8.41 Metals4U Steel tube 4 30 diameter 1.5 thickness 800 Inner steel tubes 13.69 Metals4U Steel square 8 10 Crutch pins 0.21 Metals4U Steel spring 8 6 7.5 Crutch springs 2.37 Thespringstore Steel spring 4 20 84 Springs 7.66 Thespringstore Sheet steel 1 thickness 120 110 Discs 0.18 Metals4U Aluminium ingot 4 100 Shroud 32.74 Metals4U TOTAL

65.26

Future Developments

5 6 1 2

Hinge Mechanism

4 3

Reduced Shroud Width  Reduced shroud width  Thinner sides  Cast as one piece Shroud Cap

Implementation & Future manufacture

▶ Retrofit to existing podiums:

▶ BS 8620 certification required for LLWP ▶ Meet PAS 250 specification

▶ Manufacture into new podiums:

▶ Pass all testing, as detailed in BS 8620

▶ Developed in conjunction with Overbury

▶ Interest in immediate site implementation when available ▶ Utilising large network of suppliers and manufacturers

▶ Less Material – thinner, lighter ▶ Different shrouds for different trades

▶ Different quality/strength

▶ Adjustable tension springs for a longer life span

Podium Pressure Locking Safety System