A bit of a rethink of trailer uses

A new way of thinking about the trailer, not chiefly for a bike. It's all below.

Target Consumers

Meet: Charlie & Lisa

Age: 32, 31

Physical Therapist, Photographer

Married w/ one on the way

Dog owners

Hobbyist gardeners

Urban apartment dwellers

Charlie bicycle commutes

Lisa loves walking

Charlie is a happy man. He’s married to his college sweetheart Lisa and they’re soon expecting their first child. He enjoys his job as a physical therapist and is experimenting integrating their dog, Lola, into therapy. His life is a busy one filled with baby proofing, dog food, gardening supplies and groceries.

Charlie only lives a few miles from his job, grocery stores and local shops and would love to bicycle commute more often, but always finds that his old messenger bag doesn’t comfortably hold much more than his change of clothes and laptop. There always seems to be something extra he needs to bring to work with him or something to pick up on the way home, and while he would love to ditch the car and the parking meters more often, Charlie ends up using it more often than he would like.

Lisa never caught the bike commuting bug that Charlie caught, but loves to walk the 7 blocks to the grocery and shops close to their apartment. She can never pick up to many items on her trips though because she has to then carry them home and it can be a strain.

Charlie Needs: A viable alternative to his car for in town errands and commuting.

Lisa Needs: An easy way to carry items to and from local shops.

Project Brief

For my integrative project I am designing and building an urban trailer for the urban commuter. My aims for the design is a product that is stable and maneuverable, both fully loaded and empty, light weight, and versatile in use. Pivotal to the success of an urban use trailer is its versatility; both in the size and weight of cargo being carried and in the way the trailer can be utilized. My trailer is designed to be used both as a bicycle trailer, hitched and pulled behind the bicycle, and as a push cart for use when walking. I see the trailer not as two separate uses, bicycle pulling and walking pushing, but as a trailer that is adept at both situations and could be used in either form as its primary state of use.

Initial work on the trailer was primarily shaping how to carry cargo most adeptly in a bicycle trailer situation as the initial scope of the design was bike trailer first, walking cart second. A series of fits and starts struggling to overcome and move my project beyond established designs in the bike trailer market ensued and ate a considerable amount of time. Distracted by the Burley Travoy bicycle trailer, I was ignoring a potential use of my trailer, the walking side. Personal shopping carts are quite popular in Europe and large American cities, but few take advantage of bicycles. This is where I decided I wanted my trailer to reside, straddling the bicycle trailer and walking cart worlds, with out gaining usability in one area to the serious detriment to the other.

After 4 months of ideation and models on the trailer I have a clear problem statement and am quickly moving forward. The trailer is a frame and bag integrated together with two internal compartments for organizing cargo safely. In its bicycle state, the two main wheels rest on the ground and an arm folds up to attach to the bicycle seatpost. When used as a walking cart, the attachment arm folds down and it can be used either as a pull cart or with a castored third wheel folded down, as stable pushcart.

Trailer Design

It's nice to now think only about bike trailers and not pooper scoopers, but anyway...

So, after totally being called on just emulating (a nice way to say, knocked off) the Burley Travoy, I'm back to the drawing board on the frame design. I'm still aiming for the same set of parameters for the trailer when I initially set out on this project,

• walkable and bikeable
• lightweight
• stable w/ load (riding or walking)
• customizable bag options

So initial ideas all followed the Travoy model of flat bed, foldable, support structure around the bed. I played with ideas for adding a third wheel for walking as I perceived the Travoy to be a bit tippy when standing upright (especially when loaded) as it stood on two wheels and a small leg. My goal was when walking to have at least 3 wheels on the ground for stability.

My methodology for joining the metal tubes (plastic housings basically) also was derived from the Travoy. In my trailers new form, I'll mostly likely use a similar joint as this seems to be the best and most elegant method. Also, this drawing came out well.

In sketching for the new frame I decided to work off of a single main tube as the backbone of the trailer with the main support wheels moving in towards the frame for riding and out to create a tripod with a castored wheel for walking. Walking stability was a high point with this iteration.

A guide slid up and down the main tube, keeping the wheels lined up.

The sliding guide however took up quite a bit of space on the tube that could other wise be used for mounting a frame for cargo. Thus only the top and bottom of the tube could be used for mounting, with a aimed cargo weight of 60 lbs, this would create quite a bit of stress and would need large amounts of reinforcement at the junctures adding complexity and weight.

To combat the sliding ring, a grooved guide was added to the side of the main tube, keeping the wheel struts in alignment and clearing room for more cargo supports. The raising and lowering of the legs would be accomplished by a lever on the top of the main tube connecting via cables and pulleys inside the tube to the wheel struts. Pull the cable up and it would pull the wheels in to the frame for riding. An issue with this was locking the wheels in place and the extra complexity of the pulleys and guide wheels. The more moving parts mean the more to go wrong. I realized I was moving away from Dieter Rams 10 principles, and was making the trailer more and more complex. The more complex, the greater the possibly of a mechanical failure.

So, in this vein of simplicity with stability, I'm working on elimination of as many moving parts as possible. Goodbye cables and pulleys.

This is the latest scanned sketch I have (I know, its super rough), moving the two main support wheels to be stationary (to eliminate as much stress on a joint as possible) and moving the castored wheel to the fold down third wheel. This is the direction I'm currently moving the trailer in, presently in Rhino, with the aim to be making a physical model out of pvc pipe starting the 8th.

Thanks for reading.

Just a few things,

I'm designing a bicycle trailer for urban based commuters for anyone who doesn't know. I've been sketching and surveying users (thanks to all who have given me responses!). Below are a few bag sketches. The bags will attach to a blank trailer and will accept up to several bags at once (one bag dosen't fill the entire thing). There will be three bag sizes, small, medium, large and each size will be customized for certain types of objects or tasks. For example, the small bags would be placed so they are easily reached and hold small, more valuable objects (wallets, keys, phone, iPod, babies). So far, I've just worked on the outer forms of the bags and haven't delved into the interiors yet.

A few small, upper bag ideas are what I present here.

This bag is more in the vein of the large bag, designed as a large cargo volume bag for carrying groceries for example. Basically anything big goes in here.

A few sketches on the over all form, these sketches in particular are only with two bags. The trailer would accept up to three small bags is my thinking for now.

After a tip from Shaun to check out push/pull golf bag carts I visited Miles of Golf and got the low down from the sales guy. Interesting things, pretty impressive how small they can fold up. I don't think I'll take allot from the carts in terms of holding the bags, but more from the structure and how they fold.