Lightweight rugged suspension chair: The art of Widmer's shock mitigating design.

Staples, MN – A Minnesota company is exploring an innovative and patent pending design for rotationally molding a lightweight and rugged suspension chair suitable for marine use such as in the 23 foot Flex-Ride Night Raider boat made by Widmer.
By: Andy Stone
July 7, 2011 - PRLog -- The "Lightweight Seat", (patent pending - Widmer) is designed for harsh environments where the occupant is subjected to substantial random and/or sudden dynamic forces, e.g. buffeting, pounding, bouncing and the like caused by high G-loads resulting from sudden impacts, shocks, or jarring.  Examples include the seats suitable for high-speed, rugged marine craft and employ the term “shock mitigating seats”.  The occupants of such seats must withstand extreme amounts of applied force while impacting waves at high speeds.  At the same time, weight is always a concern in high-performance vehicles and, of course, the seat must be comfortable (and, typically, rotatable and/or adjustable vertically and/or horizontally).  The seat proper is mounted on a pedestal and base which has a permanently or temporarily inflated air bag to provide cushioning and, in the preferred embodiment, approximately 4 inches of vertical clearance to absorb forces. The seat pivots around the vertical axis. Two rings help maintain the performance of the air bag.

In general, the components of the base and seat are rotationally molded polymers and marine environment suitable metals, or flexible polymers in the case of the air bag.  Materials are selected based on a sufficient balance of cost, strength, weight, ease of handling, and the like. Preferred molding materials for high performance watercraft and similar applications are high density cross-linked polyethylene (HDXLPE), which are commercially available.  Other materials known to be suitable for rotational molding may also be used, including the less costly (and less strong) high density polyethylene (HDPE) which is also commercially available.  The air bag is generally similar to that described in U.S. Patent 4,560,145 (Widmer).  In general, the air bag is an inflatable member made of a flexible material, having a uniform thickness and comprising a plurality of annular sections.  The sections sequentially taper in diameter to form a generally pyramidal shape.  There is also a ring, one between each pair of adjacent sections, extending around the outside of the air bag to provide annular support between the sections and to control bulges and stretching.  The rings provide support without the danger of the inflatable member “thinning” in the ring area when inflated. “Thinning” of the inflatable member could result in a rupture or bulge. Each ring has a circular cross section.  The air bag is inflated by conventional means.  In terms of materials, the air bag is constructed from polymer such as a suitable elastomer, e.g., a vinyl plastic of about durometer on the A scale.  The rings are made of elastic or elastomeric material, such as neoprene rubber, for example in the range of 35 to 50 durometer.  In the preferred embodiment illustrated in the Figure, the air bag provides 4 inches of cushioned vertical travel.  The seat is attached by way of the pedestal to the hull or other structure using holes or other features supporting connection.  

The lightweight seat is particularly suitable for use with the Widmer Flex-Ride Night Raider, a boat having a plastic hull which flexes and absorbs impacts produced at high speeds in rough water because the impact G-forces are absorbed by the hull instead of directly translated to the occupants. The lightweight seat disclosed here further absorbs such forces instead of translating them to the occupants, and it does so at a substantial reduction in weight, which is a critical parameter in the design of an effective boat of this type and for this application.  Visit for details.

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About Stanley Widmer Associates, Inc. We Design, Engineer & Manufacture with Advanced Methods and Materials. Stanley Widmer Associates, Inc., founded in 1971, has offices in Staples, MN and is a leader in the Rotational Molding and Marine markets. More information about Stanley Widmer Associates, Inc. can be found at .
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Tags:Widmer, Chair, Marine, Shock Mitigation, G-load
Industry:Transportation, Engineering, Business
Location:Staples - Minnesota - United States
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