# US 4,676,185 A · Free fall escape vehicle and launch > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,676,185 A - Document ID: US4676185A - Status: Granted - Kind: A - Application number: 06/774,857 - Filed: 1985-09-10 - Granted: 1987-06-30 - Earliest claimed: 1983-11-10 - Assignees: Seatek Corporation - Inventors: Gunnar Bergman - Web page: https://patentgrep.com/patent/US4676185A ## CPC - B63C 9/06: Floatable closed containers with accommodation for one or more persons inside (B63C9/01 takes precedence) - B63B 23/28: Devices for projecting or releasing boats for free fall - B63C: LAUNCHING, HAULING-OUT, OR DRY-DOCKING OF VESSELS; LIFE-SAVING IN WATER; EQUIPMENT FOR DWELLING OR WORKING UNDER WATER; MEANS FOR SALVAGING OR SEARCHING FOR UNDERWATER OBJECTS (floating nets, floating slipways, or the like for recovering aircraft from the water B63B35/52) - B63B: SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING (arrangements of vessel ventilation, heating, cooling, or air-conditioning B63J2/00; floating substructures as supports of dredgers or soil-shifting machines E02F9/06) ## Abstract A free fall escape vehicle has surfaces of a deceleration structure that decelerate the vehicle upon entry into the water at a rate no greater than 4 g to 10 g by progressively increasing in area towards an escape vessel of the vehicle. In one form, the deceleration structure is circularly symmetrical normal to its axis, which can be approximated by a series of spaced-apart shells, each shell being a zone of a sphere the center of curvature of which is at or above the center of gravity of the escape vehicle; the condition can also be approximated by truncated sections of right circular cones. An escape vehicle similar to a lifeboat has a wedge-shaped deceleration structure with the sides of the wedge paralleling the fore-and-aft axis of the vessel, the structure can be approximated by a series of right circularly cylindrical shells or flat plates both having an effective center of curvature at or above the center of gravity of the vehicle. A double-wedge escape vehicle easily stores and has good control over transverse decelerations. A launch apparatus forces the vehicle to swing by gravity away from the stricken platform or vessel and releases it with the vehicle' s vertical axis as nearly parallel as possible to the velocity vector at water entry. ## Claims ### Claim 1 A launch and an escape vehicle for use on ships and off-shore platforms in evacuating personnel from them in emergencies comprising: a. an escape vessel for the personnel; b. a non-buoyant deceleration structure depending downward from the escape vessel and defining an envelope of progressively increasing impact area for impacting the water after free fall, the area increasing from an end remote from the vessel towards the vessel, the change of area with distance of the envelope from the end of the envelope remote from the escape vessel being such that the vehicle decelerates from the resistance of water after entrance into the water after falling from a predetermined free fall height above the water, the deceleration being at a rate no greater than from about 4 g to about 10 g, the deceleration structure having a hollow interior and passage means through the envelope for rapid flooding of the interior, the curvature of the envelope being such that substantially all of the impact forces on the envelope from impacting the water are directed at or above the center of gravity of the vehicle; c. a carriage above the vessel having fore and aft guide means; d. sling means supporting the carriage from the ship or platform to develop pendulous movement of the vehicle upon release from the stored position and a horizontal component of motion of the vehicle at launch; and e. fore and aft tracks of the vessel engaging the guide means to vertically support the vessel from the carriage in a stored position, the forward track being inclined at an angle with respect to the aft track such that with travel of the tracks on the guides an angular velocity is imparted to the vessel sufficient to rotate the vessel so that its vertical axis as viewed at rest in a calm sea approaches parallelism with the velocity vector when the vehicle impacts the water. ### Claim 2 (depends on 1) The launch and escape vehicle claimed in claim 1 wherein the deceleration structure includes a plurality of stacked and spaced apart members with each member having a surface to impact the water, the members extending inwardly toward the center of the structure and terminating with lateral spacing between transversely adjacent members so that the center of the structure is open, and frame means for connecting the members to the vessel. ### Claim 3 (depends on 2) The launch and escape vehicle claimed in claim 2 wherein the envelope is shaped like an inverted bell. ### Claim 4 (depends on 3) The launch and escape vehicle claimed in claim 3 wherein the escape vessel and the deceleration structure are circularly symmetrical about an axis corresponding to the vertical axis of the vehicle when it is at rest in a calm sea. ### Claim 5 (depends on 4) The launch and escape vehicle claimed in claim 4 wherein the members are spherically curved. ### Claim 6 (depends on 4) The launch and escape vehicle claimed in claim 4 wherein the members are conical frustrums. ### Claim 7 (depends on 2) The launch and escape vehicle claimed in claim 2 wherein the escape vessel and the deceleration structure have a fore-and-aft length greater than their beam, and the envelope is shaped like a wedge with the outer sides of the wedge paralleling the fore-and-aft axis of the vehicle. ### Claim 8 (depends on 7) the launch and escape vehicle claimed in claim 7 wherein the members are right circular cylindrically curved. ### Claim 9 (depends on 7) The launch and escape vehicle claimed in claim 7 wherein there are two of the deceleration structures of the defined wedge shape arrayed in an inverted "V". ### Claim 10 A free fall escape vehicle for use on ships and offshore platforms comprising: a. an escape vessel for occupants of the vehicle; b. a non-bouyant deceleration structure depending downward from the escape vessel and defining a wedged shape envelope having an impact area for impacting the water that progressively increases from an end remote from the escape vessel to the escape vessel, the deceleration structure having a hollow interior and passage means through the envelope for rapid flooding of the interior while the structure enters the water; c. the change of area of the envelope with distance from the end of the envelope remote from the escape vessel being such that the vehicle decelerates from the resistance of water after entrance of the deceleration structure into the water after the vehicle falls from a predetermined free fall height above the water, the deceleration being no more than about 4 g to about 10 g; and d. the center of curvature of the envelope being such that substantially all of the impact forces on the envelope from impacting the water are directed at or above the center of gravity of the vehicle. ### Claim 11 (depends on 10) The escape vehicle claimed in claim 10 wherein the impact area of the deceleration structure includes a plurality of stacked, concentric members spaced apart from each other. ### Claim 12 (depends on 11) The escape vehicle claimed in claim 11 wherein the center of curvature in transverse cross-section of the members is at or above the center of gravity of the vehicle. ### Claim 13 (depends on 11) The escape vehicle claimed in claim 11 wherein the members have right circular cylindrical curvature. ### Claim 14 (depends on 11) The escape vehicle claimed in claim 11 wherein the escape vessel and the deceleration structure have a fore-to-aft length greater than their beam and the deceleration structure envelope is wedge shaped with the outer sides of the wedge paralleling the fore-and-aft axis of the vehicle. ### Claim 15 (depends on 14) The escape vehicle claimed in claim 14 wherein there are two of the deceleration structures of the defined wedge shape arrayed in an inverted "V". ### Claim 16 A free fall escape vehicle for use in evacuating ships and off-shore platforms comprising: a. an escape vessel for occupants of the vehicle; b. a non-buoyant deceleration structure depending downward from the escape vessel, the decleration structure (i) defining an envelope of progressively increasing impact area for impacting the water after free fall, the impact area increasing from an end remote from the vessel towards the vessel; (ii) including a plurality of stacked and spaced apart members with each member having a surface to impact the water and with spacing between members providing a passage for water to rapidly flood the interior of the deceleration structure, the members extending inwardly toward the center of the deceleration structure to termini spaced from the center so that the central volume of the deceleration structure is open, and (iii) having frame means for connecting the members to the escape vessel; c. the rate of increase of impact area from an end remote from the vessel towards the vessel being such that from a predetermined free fall height the rate of deceleration of the vehicle is no more than from about 4 g to about 10 g; and d. the curvature of the members being such that substantially all the impact forces on the envelope from impacting the water are directed at or above the center of gravity of the vehicle. ### Claim 17 (depends on 16) The free fall escape vehicle claimed in claim 16 wherein the envelope is shaped like an inverted bell. ### Claim 18 (depends on 17) The free fall escape vessel claimed in claim 17 wherein the escape vessel and the deceleration structure are circularly symmetrical about an axis corresponding to the vertical axiss of the vehicle when it is at rest in a calm sea. ### Claim 19 (depends on 18) The free fall escape vehicle claimed in claim 18 wherein the members are spherically curved. ### Claim 20 (depends on 18) The free fall escape vehicle claimed in claim 18 wherein the members are conical frustrums. ### Claim 21 (depends on 16) The free fall escape vehicle claimed in claim 16 wherein the escape vessel and the deceleration structure have a fore-to-aft length greater than their beam, and the envelope is shaped like a wedge with the outer sides of the wedge paralleling the fore-and-aft axis of the vehicle. ### Claim 22 (depends on 21) The free fall escape vessel claimed in claim 21 wherein the members are right circular cylindrically curved. ### Claim 23 (depends on 21) The free fall escape vessel claimed in claim 21 wherein the members are flat. ### Claim 24 A free fall escape vehicle for use on ships and off-shore platforms comprising: a. an escape vessel for occupants of the vehicle; a non-bouyant deceleration structure depending downward from the escape vessel and defining an inverted, bell shaped envelope having an impact area increasing from an end remote from the escape vessel to the escape vessel, the deceleration structure having a hollow interior and passage means through the envelope for rapid flooding of the interior while the structure enters the water; c. the change of area of the envelope with distance from the end of the envelope remote from the escape vessel being such that the vehicle decelerates from the resistance of water after entrance of the deceleration structure into the water after the vehicle falls from a predetermined free fall height above the water, the deceleration being no more than about 4 g to about 10 g; and d. the curvature of the envelope being such that substantially all of the impact forces on the envelope from impacting the water are directed at or above the center of gravity of the vehicle. ### Claim 25 (depends on 24) The escape vehicle claimed in claim 24 wherein the impact area of the deceleration structure includes a plurality of stacked, concentric members spaced apart from each other. ### Claim 26 (depends on 25) The escape vehicle claimed in claim 25 wherein the members have spherical curvature. ### Claim 27 (depends on 25) The escape vehicle claimed in claim 25 wherein the impact area of the members has the curvature of a conical frustrum. ### Claim 28 (depends on 25) The escape vehicle claimed in claim 25 wherein the escape vessel and the deceleration structure are circularly symmetrical about an axis corresponding to the vertical axis of the vehicle when at rest in a calm sea.