In order to hold my my drip tray up when in use i need a support mechanism, preferably something which is quick and easy to use, like that of a pram hood. These are a number of mechanisms which I considered
Ratchet and Pawl
A ratchet allows continuous linear or rotary motion, It’s teeth are made up of a steep side and a gently sloping side. As the Ratchet turns the pivoting, spring-loaded pawl sides over the sloping side of the gear and snaps closed over the steep edge locking it into place. The ratchet is able to move in a continuous forward motion, however without a release level (seen above), it only works in one direction. “Ratchets can only stop backward motion at discrete locations (i.e. at each successive gear). As a consequence ratchets can allow a limited amount of backward motion called backlash or “play.”” (Creative Mechanisms, 2017) This would work well for pulled the tray open but could make it more fiddly to close.
I felt the mechanism in a pram hood may be more appropriate as it seemed work in both directions with ease. I visited the pram department in my local Toys R Us and discovered most pram hoods use 2 way Ratchet system which can be pulled up into place and simply pushed back down after use. Also in contemporary prams most used plastic mechanism which would be lighter and cheaper to produce. However these mechanisms didn’t seem strong enough to support the size of the drip tray which would need to be 2m wide to accommodate an average bicycle.
Finally for my piece I feel the most appropriate mechanism to use would be a simple friction stay. This was something I noticed on the hood of a cheaper buggy my sister owns. Although plastic may not be strong enough to hold up a large drip tray they are widely produced in pressed aluminium. Also they are extremely simple to use so customers should have no difficulty opening and closing the piece.
As my drip tray is large in scale I could use a sturdier version of this mechanism as seen on PVC windows. As pressure is applied the hinge snaps into position and tension holds the mechanism open. To close, the hinge is simply knocked and falls apart as the tension is released.
- Creative mechanisms (2017) Ratchets[Online] [Date Accessed 6th May 2017] https://www.creativemechanisms.com/ratchets