Collapsibility
Collapsibility, the first and most important concept of this redesign, was established due to the awkward width of the frame with respect to a normal doorjamb. With most doorjambs having a max width of 30 inches, the frame track width (distance between the center-points of each rear axle) is currently sized too large to fit through. If the previous two frames were ever actually put on the market, the jogger would have to have the tires removed, and the frame would have to be carried through any doorways. Obviously, since the target consumer audience for this product consists of those with some sort of disability or handicap, lifting the frame and trying to carry it through a doorway would be next to impossible for many consumers. This obstacle, coupled with the limited transportation ability due to the sheer size of the jogger, led to the exploration of the concept of collapsibility.
The first key to understanding what is needed for collapsibility lies in the head mounting tube at the front of the jogger. In previous models, this mount has been a fixed tube welded rigidly to the frame, which is not conducive to a collapsible design. The new model requires a hinge in place of the solid tube that will allow the frame to collapse, while at the same time not allowing the frame to flex outward. Outward extension of the frame in this case would cause some degree of unpredictability, destroying the structural integrity of the frame. For this reason, a custom hinge has been designed to meet these requirements.
Inspired by both a simple door hinge and a break-action firearm hinge, the initial hinge design for the head tube of the jogger consists of two separate halves which operate much like that of a door hinge. Each half has multiple cylindrical tubes, as shown in the figure below:
The first key to understanding what is needed for collapsibility lies in the head mounting tube at the front of the jogger. In previous models, this mount has been a fixed tube welded rigidly to the frame, which is not conducive to a collapsible design. The new model requires a hinge in place of the solid tube that will allow the frame to collapse, while at the same time not allowing the frame to flex outward. Outward extension of the frame in this case would cause some degree of unpredictability, destroying the structural integrity of the frame. For this reason, a custom hinge has been designed to meet these requirements.
Inspired by both a simple door hinge and a break-action firearm hinge, the initial hinge design for the head tube of the jogger consists of two separate halves which operate much like that of a door hinge. Each half has multiple cylindrical tubes, as shown in the figure below:
The two halves of the hinge line up when the hinge is fully assembled so that the front fork’s mounting tube can be run through the center of the assembly. The initial conceptual design of the assembled hinge design is shown in the figure below:
The next two figures below show the new frame in its open, ready to use position, and in its collapsed position