Custom Ramp Design Case Study - London Underground (TFL)
Posted on August 24, 2016
To design a ramp to enable cleaning staff to transfer their cleaning trolleys from an elevated station platform, down into a train carriage.
The ramp needed to be between <1600mm in width, needed to weigh no more than 15kg, had to have a weight capacity (SWL) of 250kg, require minimal maintenance and most importantly, be easy to deploy and use.
- The ramp needed to fill the door aperture and needed to be 1500 - 1550mm in width
- The ramp needed to be 1200mm -1350mm in length
- The ramp had to have a safe working load of at least 250kg
- The guard edges had to be cut back at the base of the ramp to eliminate trip hazards for the cleaners.
- The ramp had to be easy to deploy and easy to use
- The ramp had to be portable, with a total weight of no more than 15kg.
The issues to overcome:
- How to design a ramp that could maintain a SWL of 250kg across a width of 1500mm, the normal width being 934mm
- How to make a ramp of that width that is easy to deploy and manageable by one person
- How to keep that ramp under a total weight of 15kg
- How to cut back the guard edges, which are normally an integral part of the strengthening of any ramp, whilst allowing the weight capacity to be maintained
We decided to design the ramp as a two piece ramp that would lock securely together to form a single piece ramp. The locking mechanism was pretty simple, fixing two locator pins on one half that would drop into two locator holes on the opposing half, these would allow the ramp to be connected and disconnected in a matter of seconds using specially sourced recessed handles.
Once we'd established what the basic design would be, it was then an issue of ensuring that the other requirements were met. One of the main issues we were concerned with was how to maintain the weight capacity across an increased width, on a ramp with shortened guard edges, fortunately it was the latter issue that helped us come up with a solution. By cutting the guard edges back and by cutting two recessed 'carry handles into the remaining guard edge, this reduced the weight of the ramp significantly, allowing us scope to manufacture the ramp with an increased number of laminates and with integral strengthening rods. This resulted in the ramp exceeded the required weight limit, whilst not compromising on the overall weight limit.
We completed the ramp in a highly visible yellow finish, with a hard wearing no slip grip finish.