The ball and socket joint uses a locking mechanism which can be engaged or released. Two ways of implementing this design are considered. A mechanism attached to a height-adjustable tray assembly facilitates the scooping of food by rotating the plate. The Linkage Figure 3 shows a solid model of the linkage assembly. The range of motion of the mechanism is constrained by the geometry of the 2 four-bar linkages.
Springs provide a damping force and stabilizes the linkages in any orientation that they are placed.
The degrees of motion of the linkages are shown in the figure. The Ball and Socket Joint in the feeding device is specially designed with a lock and release mechanism. This allows the user to control the degree of motion of the ball joint. This is accomplished by a miniature spring-cable system, similar to that of a bicycle breaking system. Figure 4 shows the schematic of the cable release mechanism.