The above figure shows how a four-bar linkage can be used in a rollerblade braking application. The first position is the skating (not engaged) position and the second, braking (from LINCAGES animation). The boot cuff, which is firmly clamped to the lower leg, acts as the input link. When braking is required, the in-line skater moves his or her toe forward, causing rotation of the lower leg about the ankle joint. The resulting relative rotation between the cuff and the boot moves the brake pad down into contact with the skating surface, thus slowing down the speed of the in-line skater.
This mechanism was designed by Rollerblade Inc. using LINCAGES software.
The above diagram shows the three positions of a pick-and-place mechanism designed by 3M using LINCAGES software. The linkage is used to feed diskettes automatically from a storage magazine and place them onto an assembly conveyor belt. Although the first and the last positions are of primary concern, the intermediate position is prescribed to help guide the diskettes in the correct direction. Although robots are often used in a pick-and-place application, a cost-effective four-bar linkage is sufficient here. The design constraints that were considered were: (1) the four-bar should be relatively compact, (2) the ground pivots should be located in reasonable locations, and (3) the rotating links should not interfere with the conveyor belt or the storage magazine as the four-bar performs its task.
The mechanism shown above was a redesign of a camera opening mechanism by Polaroid Inc. The first diagram shows the open position of the initial concept and the second, the closed position. The mechanism is a seven-bar with two degrees of freedom. Four highly constrained design positions were developed from camera size, optical, and mirror/ shutter housing interference constraints. LINCAGES was used in searching the solution and thus synthesizing the mechanism.