Street FurnitureMaterials and Structures 2DES08118TRI 2 – 2013Jack Lennie

Street FurnitureIndex - Introduction - Research - Initial Concepts - Chosen Concepts - Design Development - Design Review - Structural Analysis - Material Selection - Sustainability - Ergonomics - Design Detail - Design Outcome - Company Policy - References

Introduction

This design proposal in response to the request for tender by the city of Milan to provide lockers for the Milan design week festival. These lockers have been commissioned for the use not only in Milan but all of the design festivals around the world. The reason I have chosen lockers is it is common to see pieces of street furniture such as chairs, benches, shelters, and billboards, However it is irregular to see lockers at these events. I think having lockers at these events would dramatically increase how enjoyable the event was for someone as they would not have to carry any unneeded jackets or bags around with them. This concept coupled with the unpredictable Scottish weather I think makes the idea of lockers at a festival very viable.

Research

First of for my research I looked into an array of festivals and what is already out there with regards to street furniture at these festivals. One of the first things that was very apparent was the exceptionally wide array or festivals and genres. The duration is also a variable factor in all of the festivals around the world. Location of the festivals also proved a valuable piece of research as my product will have to take this heavily into consideration with regards to weather, temperature and whether or not it is located indoors or outdoors. Another consideration for the product with regards to location is the language, If this product is to be used worldwide at festivals all annotations and decals should be understandable in a variety of languages.

ResearchI researched “Links Lockers” to enhance my design by looking at what could be improved with there lockers and how to make them viable for outdoor use.

Links lockers are commonly used in the work place and in leisure centres. Like mine they are designed for short stay.

The first problem I found with these lockers if they were to be used for outdoor use is the need to be bolted together then harnessed to a wall or similar structure.

They are made from sheet steel that is cut, punched and folded to shape then all the parts art riveted together. Links tries to keep all the seems to the inside of the locker to increase the security. The sheet steel is powder coated for a tough hard wearing finish however if this were to come off and the lockers where to be used in an outdoor environment they would soon rust and weaken as a result.

The hinges on these lockers also beg to question how secure they are as the hinge barrel is external meaning if someone wanted to break into them they could knock the hinge out of place or possible break it off completely with relative ease if the lockers where not monitored

Research

Initial ideas My Idea is for short too medium stay lockers where people can leave there belongings so that they do not have to carry them around and can enjoy the event more freely,The lockers will be combination lock to prevent the loss of keys.

Initial ConceptsInitial ideas

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Initial ConceptsInitial ideas

Initial ConceptsInitial ideas

Chosen ConceptChosen design

Design DevelopmentAlthough these lockers have been designed for the London Design festival they have not been designed solely for this. I have chosen a product that will serve many festivals around the world, indoors or out. This array of festivals, in particular short one day festivals or festivals where attendees do not stay over at the event. Festivals such as the Edinburgh fringe, Amstel beer festival, or Milan Design week. The lockers allow for people to leave objects such as jackets and bags that they would otherwise have to carry around for the duration of the event in a secure location allowing them to enjoy the event as fully as possible.

Having a design that is not based solely on one festival is also far more sustainable as these lockers are not discarded or kept in storage for the majority of the year after the festival has concluded. In fact they are transported around the globe to any festival that wishes to use them. However due to the amount of transportation they may undertake it is vital that they are as efficient as possible to do so with. Meaning they must maximise the space within the chosen transport method.

Design Development

Design ReviewThe initial problem with this design is the danger of it being tipped over, Although there is a great weight of water/ sand mass in the bottom of the lockers it can not be certain that the lockers will be able to be put against a wall or solid object to prevent tipping over onto there backs. To combat this problem I propose to make the lockers on both side so that the design sits back to back, this means the lockers would still be one sided as pictured above but will have the option to be bolted back to back. This means if there is not a solid object for the lockers to sit against to prevent tipping they will be able to be bolted together back to back supporting each other.

Design Development

Design ReviewHaving the two lockers back to back resolves the stability problem and makes the overall structure much safer. For shipping and transport to be as efficient as possible and the C02 footprint to be as low as possible the lockers need to not leave any free space in the back of a truck ( or however they are transported). To rectify this I propose for the protruding lockers to be symmetrical along the x axis to allow for the lockers to sit and push into each other eradicating that free space and maximizing efficiency when transporting. For example if the top left corner is protruding 50mm from the face of the main body then the bottom left corner is set back 50mm from the face of the body. This in turn will decrease the carbon footprint. Also for this to work as well as possible the depth of the seat must be equal to the depth of the body that houses the lockers.

Design Development

Looking at the configuration of the lockers having only three rows high would mean that for the lockers to fit together as described in the previous page would mean the middle row of lockers would have to all be the same depth, this would cause one flat row in the middle ruining the aesthetic. To combat this I have chosen to make the lockers 4 rows high. This allows the staggered aesthetic of the lockers to work with best with the stacking method. The lockers size will be decreased by this new configuration but as the lockers have been designed for only short stays I dont think this change will be at the cost of the lockers functionality.

Design Development Also for this to work as well as possible the depth of the seat must be equal to the depth of the body that houses the lockers. Meaning when the two lockers are fitted together the will equal the width of one of the locker units, The depth of one unit and the height of one unit plus the height of the seat part of the unit.

Structural Analysis

One of the lockers stress hotspots would be the locker hinge as there would be a high shear stress on these areas if someone where to hang from the lockers or swing on them,The load is indicated by the purple arrow where as the stress is indicated by the green arrows above. This shear strength would be directed onto the steal pin hinge (indicated in red above) between the locker door and the locker itself. Due to the Steel being stronger than the rotationally moulded locker door a small machined aluminium alloy washer will be placed into the holes on the top and bottom of the locker door and the locker itself where the steel pin runs through to better disperse the load.

Locker

Locker Door

Hinge Pin

Structural AnalysisAnother of the lockers major loads that must be taken into account is the compressive load exerted on the seat at the bottom. Due to the hollow polypropylene structure the compressive load may be to much for the empty structure. However there are two major features to combat this compressive load and help the structure negate the load. Firstly as the seat is positions along the edges of the structure these edges will act as a strut to support the users weight, also the air inside the hollow structure will be displaced with water or sand to add ballast to the lockers. This ballast will also displace the air inside lockers creating a stronger force to act against the compressive load of people sat on the lockers as water/sand is not as compressive as air.

Material Selection

The main construction of the lockers will be rotationally moulded polypropylene with alloy and steel part to construct the locking mechanism and steel lock pin. The locker doors will also be made from rotationally moulded polypropylene, these will all be uniform in size and shape so that only one mould is needed for this part cutting costs dramatically.The hinge mechanism between the locker doors and the main body of the product will be a stainless steel pin to prevent from rust and corrosion and elongate the life of the lockers. The steel is also stronger than alloy so that the lockers are far more secure.

Material SelectionWith regards to finishes

The main body of the lockers will all be coloured polypropylene, this colouring is done when the plastic is being injected into the mould meaning if the locker wear or are scratched and damaged in any way the colour will not lift off. One major factor with colour choice is what colours will last as this product will serve many festivals over its lifetime. Through my research I have noted that red is not a colour that is suitable for this design as the pigment in red fades rapidly with exposure to direct sunlight. The locker doors will also be coloured separately in the same way as the body of the design, this is not only for aesthetics but it will help to differentiate the lockers, the colour couples with the locker number that will be applied through a decal that is melted onto the part whilst it is being rotationally moulded will minimalise the chances of people forgetting or getting confused as to which locker is theirs.

Sustainability

The main body of the lockers in constructed wholly of poly propylene which has a recycling grade of “5”. by not combining any other materials to the main body through melting or fixings it makes the break down for recycling very simple. This same ethos is repeated in the locker doors hinge pin and spacers, This tool free construction and deconstruction makes for an easily recycled product that requires minimal man hours, tooling and provides maximum ease of recycling.

However the actual locking mechanism is an off the shelf combination lock with latch, although to break down for recycling the locking mechanism would need more man hours and be more complicated by using an off the shelf product you not only save time in developing but money as you do not have massive setup costs to manufacture them.

Ergonomics

The ergonomics I have considered are the seat height and the locker handle usability With this in mind the seat position will need to be 430 mm in height and 420 in depth. This means that the bottom ballast will not be to far out to restrict reach to the upper row of lockers.The reach of the upper most lockers must also be taken into consideration so that they are accessible to people. For this reason the upper edge of the lockers will stand at 2 meters from the ground. As all the handles located at the bottom corner of the lockers the top handle would side at 1.7 meters from the ground again making even the upper lockers accessible to the 95%ile of peoples reach. I have also incorporated the fact that the reach will be slightly impaired due to the seat at the base of the lockers jutting out slightly.

Design Detail -Parts, Locker Door

Design Detail- Parts, Hinge Pin

Design Detail- Parts, Locker Door

Design Detail- Parts, Main body

Design Outcome

Company Policy

As a company we are devoted to sourcing our materials and manufacture as close to home as possible. We aim to find manufacturers within the UK, this not only allows us to boost our economy it massively reduces our carbon footprint and allows us to meet with everyone involved in all our projects face to face. In turn delivering a better more environmentally friendly product to our consumers.

References

Links Lockers http://www.linklockers.co.uk/

Matrix Polymershttp://www.matrixpolymers.com/

Polypropylene Datahttp://www.icis.com/