Abstract: A wheelchair or a vehicle for sand or loose soil comprises one or more skids, each equipped with a spring-loaded roller or roller plate. Examples of the vehicle include a wheelchair and a planetary rover. Preferably, a beach, shower or pool wheelchair comprises two front skids in place of front wheels. The skids provide a resistance-free, broad footprint in the sand and a low-resistance narrow footprint when used on hard, e.g. boardwalk, surfaces. A wheelchair may further comprise a lightweight, easy to fold frame, which closes like a pair of eyeglasses. Still further, a wheelchair may provide a removable and reclining lounge chair seat to allow the user to exit the wheelchair to enter the water or sit and recline on the sand. In addition, dog bone or dumbbell shaped wheels provide the wheelchair strong, lightweight support and a wide footprint and can be equipped with grip notches for user self-propulsion.

Abstract: A wheelchair or a vehicle for sand or loose soil comprises one or more skids, each equipped with a spring-loaded roller or roller plate. Examples of the vehicle include a wheelchair and a planetary rover. Preferably, a beach, shower or pool wheelchair comprises two front skids in place of front wheels. The skids provide a resistance-free, broad footprint in the sand and a low-resistance narrow footprint when used on hard, e.g. boardwalk, surfaces. A wheelchair may further comprise a lightweight, easy to fold frame, which closes like a pair of eyeglasses. Still further, a wheelchair may provide a removable and reclining lounge chair seat to allow the user to exit the wheelchair to enter the water or sit and recline on the sand. In addition, dog bone or dumbbell shaped wheels provide the wheelchair strong, lightweight support and a wide footprint and can be equipped with grip notches for user self-propulsion.

Abstract: Disclosed is a high-pressure mixing head for the mixing of at least two reactive plastics material components and the foaming of these components, the mixing head comprises a mixing chamber (18) which has opening thereinto nozzle orifices (22; 24; 41) for the plastics material components and a blowing agent, and in which a metering plunger (20) is mounted for reciprocating movement. The mixing chamber (18) opens into a discharge section (16) of greater dimensions which, thus, acts as a stabilizing zone. On the mixing chamber outlet (26), a variable damper element (purging plunger 12; damping plunger 40) is provided which provides for variable restriction of the mixing chamber outlet (26). The damper element greatly reduces the mixing turbulence within the mixing chamber, such that, in combination with the discharge section of greater dimensions, the plastic foam mixture flows out from the mixing head so smoothly that spatter-free foaming even in open molds becomes possible.

Abstract: Disclosed is a high-pressure mixing head for the mixing of at least two reactive plastics material components and the foaming of these components, the mixing head comprising a mixing chamber (18) which has opening thereinto nozzle orifices (22; 24; 41) associated with said plastics material components and a blowing agent, and in which a metering plunger (20) is mounted for reciprocating movement. The mixing chamber (18) opens into a discharge section (16) of greater dimensions which, thus, acts as a stabilizing zone. On the mixing chamber outlet (26), a variable damper element (purging plunger 12; damping plunger 40) is provided which provides for variable restriction of the mixing chamber outlet (26). The damper element greatly reduces the mixing turbulence within the mixing chamber, such that, in combination with the discharge section of greater dimensions, the plastic foam mixture flows out from the mixing head so smoothly that spatter-free foaming even in open molds becomes possible.