Abstract: A seat cushion features an inner core of an open-celled compressible foam material hermetically sealed within a first inner cover which is of a size to fit loosely about the inner core. An outer cover is of a size and shape substantially as that of the inner core and is nominally larger to allow the material of the inner cover to shift within the space between the inner core and the outer cover. A tube incorporating a valve leads from the space within the inner cover through the covers to the atmosphere. The cushion is naturally self-inflating when the valve is open so need not be blown up by the user with this or her lungs or other air source. A sitter on the cushion can adjust its compressibility by opening the valve, or deflate the cushion entirely for storage or for portability, then close the valve to maintain the cushion deflated.

Abstract: A pair of cushions are hinged to each other and also hingedly attachable to retractable bleachers such that the cushions hang down to form a wall of protective padding over the front of the bleachers when retracted, but when the bleachers are extended the cushions can be flipped-up on top of the seats for spectators to sit on.

Abstract: A weight lifting machine substitutes a noncumulative force or constant tension type spring for some of the individual weights with which the machine would otherwise be equipped, the tension required to unwind the spring being equal to the sum of the omitted weights. The remaining individual weights function as before but when additional resistance, greater than their sum, is wanted, the spring is connected into the lifting mechanism.

Abstract: The typical helical springs used to support the bed within the frame of a trampoline or the like are modified to incorporate adjustable hooks threadedly anchored within the springs at one end so that their overall length, and thus the tension on the bed, can be varied and overstretching accommodated. Two principal versions are disclosed, the more preferred one including an additional inner spring biasing the adjustable hook to a retracted position.

Abstract: A form of trampoline apparatus for use in connection with tumbling and the like employs a relatively long-narrow bed resiliently suspended between a pair of side rails only so that the two opposite ends of the bed are unobstructed by any cross rails or other structure. The two rails are supported above the floor by a substructure which interconnects them and holds the rails apart against the tension of the bed. One end of the bed inclines upwardly toward the remainder of the bed which is horizontal with respect to the floor. The trampoline is narrower relative to its length and having dimensions such that the length is substantially three times or more its width to provide directional rebound characteristics.

Abstract: A runner traverses a long distance by running back and forth over a short pathway or lane laid out on a floor and at each end of the lane reverses his direction by partially turning just before striking one of a pair of resilient backstops, each pair having an inverted U-shaped frame, placed at the ends of the lane. In other cases a backstop may be used at one end only of the lane, the runner thus traversing the lane only twice. Each backstop, due to its angle with the floor, rebounds the runner back in the opposite direction at substantially the same speed at which he struck the backstop. In these manners and with such apparatus not only can longer distances be effectively run over relatively short lengths of gymnasium floor, for instance, but various types of foot races can also be conducted indoors.

Abstract: The hooked ends of the springs or like members by which the bed of a trampoline or similar apparatus is suspended from its frame are equipped with protective sleeves of flexible material. The sleeves are split at their outer ends to form two flaps, one of which covers the exposed ends of the hooks to prevent injury to a performer inadvertently striking them, while the two flaps together are foldable back onto the sleeve to assist hooking and unhooking of the springs to and from the bed and the frame.