REBOUND CHECKS, devices attached to the running-gear of automobiles and designed to check the rapid reaction of a spring which has been suddenly compressed, and thus prevent the bouncing movement of a car, which is in duced by the extreme resiliency of modern springs. This reaction causes a bouncing move ment, which affects the steering, and by its lift ing action tends temporarily to diminish the grip of the driving wheels on the road. It is also calculated to produce side-slip, sets up a violent sway at corners and causes discomfort to passengers. Rebound checks are of varied types, one in very general favor consists of two arms, one attached to the frame and the other to the spring centre. These arms form an shaped link connected by a disc. The disc forms a friction-grip which tends to make the car spring drag when recovering, so that any vio lent reaction of the frame is absorbed by check. Another variety, often seen on light cars, consists of a circular box attached to the frame and containing a wound-up spiral spring of great strength, the outer end of which is at tached to the axle or spring clip. The action in
both varieties is the same, a too-great reaction of the frame being prevented in both cases. Another method consists in introducing friction in the working of the springs. This is some times done by clipping together the leaves of the springs. Check-leaves are also introduced above the long spring leaf and help to retard the action of the latter when it shoots its load upward on the rebound. Another device, a cam shaped piece with an arm, is set in a depression. When the arm is rotated — which only happens when the spring is suddenly compressed — the two rings are separated more and more from one another which action tends to squeeze to gether the parts of a minute clutch, one part of which is Ix R ed to the frame and the other to the movable cam and arm-piece. See SHOCK ABSORBERS.