Abstract: An illuminated sign letter structure made up of an extruded plastic strip having a metal foil encased therein. One end of the strip is enlarged and has a ledge projecting outwardly from the strip. The opposite sides of the ledge are parallel and smooth for receiving the edges of a letter-form. The extruded plastic strip is formed into a letter shape and a letter-form of the letter shape is fixed in the frame to engage either the inner or the outer parallel, smooth ledge side. The metal foil may be straight or the end of the foil at the enlarged end of the extruded strip may be bent inwardly into the enlarged end.

Abstract: A magazine floor plate latch for releasing the hinged floor plate of a cartridge magazine in a bolt action firearm. A spring biased latch having two upper legs and one lower leg is positioned in a central aperture in the front face of a trigger guard. The latch is adapted to pivot about a pivot point at a line of contact between a pointed surface in the trigger guard extending upward and fitting into a notch formed in the lower leg of the latch. The latch is normally biased by a spring so that one of its upper legs blocks the floor plate to keep it from swinging open about its hinged end. The floor plate is released by applying pressure on the latch so that it pivots until this upper leg no longer blocks the plate. This upper leg has a curved locking surface with a center of curvature offset from the pivot point to enable the locking surface to relatch the floor plate tightly against the bottom of the magazine as the latch pivots to its normally spring biased position.

Abstract: The water fowl decoy includes a body comprised of a rigid plastic outer shell filled with buoyant foam plastic material and a depending weighted keel comprised of a rigid plastic shell filled with concrete and having throughbores at each end thereof for receiving anchor ropes or stakes.

Abstract: An improved landing net of the type having a handle supporting a frame having an opening at the end of the frame away from the handle and a "U"-shaped member pivotally secured by the ends of the "U"-shaped member to the frame at the opening for providing a slotted support for a net secured to the frame and "U"-shaped member, provides a position lock for one or both pivoted ends of the "U"-shaped member, converting it from a floppy, still-water landing net to a versatile landing net usable in high current flow situations for netting large fish head-first with fishing boat underway, for example, or for netting tail-first, if desired, and without sacrifice of folding compactly to a carriage position, from which position the invention is instantly deployable by a snap of the wrists.

Abstract: Fishing lure includes a one-piece body of generally torpedo shaped configuration with opposed end portions that each include a rod-like portion and a tapering portion. A propeller and sleeve of colored material are mounted along one of the rod-like portions.

Abstract: A bottom fishing lure consisting of a fishhook having a weighted, non-buoyant head adapted to be pulled head first along the bottom surface of a body of water by a fishing line, and adapted to carry a trailing bait, the hook being supported on the bottom on its bight portion and on an adjacent pair of a series of resilient legs carried by and extending radially from the head, each effective leg being movable during forward movement of the lure alternately to drag along the bottom, and to be resiliently flexed by the drag resistance, and then to free itself from the bottom and snap forwardly when the flexure force has built up to a sufficiently high level, the flexing and recovery pattern of the legs being such as to impart a forward "walking" motion, accompanied by a lateral waggling of the hook and bait. This creates an unusually lifelike "swimming" motion to the hook and bait which is highly attractive to feeding fish.

Abstract: A fishing device wherein more than one portion thereof may be selectively and quickly broken off to decrease the weight of the fishing device. The fishing device comprises a substantially spherical body with a neck and hook attached thereto. The fishing device also comprises a tail portion arranged at approximately a 45.degree. angle to the hook with the tail portion comprising at least two removable weights which when removed decreases the weight of the fishing device.

Abstract: A leech keeper including: a hollow wall container with threads positioned on the top exterior; a nested strainer including holes in the sides and bottom with a weight string hole affixed to the bottom and a lip at the top with interior threads; and a lid including a hollow portion for flotation, interior threads for screwing onto the container holding the strainer, and exterior threads for engaging with the interior threads of the strainer. The double-lined construction of the container keeps the water cool for extended periods of time and provides a watertight container for storage and flotation of the leeches. This provides an environment for the leeches to remain healthy and to live longer, ensuring better fishing.

Abstract: A rodent killing device is provided with a plurality of units of feeding and killing chambers, with each feeding chamber positioned directly above a killing chamber, so that the floor of the feeding chamber also forms the ceiling of the killing chamber. The feeding chamber attracts a rodent by bait, which then becomes entrapped within the feeding chamber, whence it is transmitted to the killing chamber by sliding the floor of the feeding chamber outwardly. The killing chamber destroys the rodent by a plurality of spikes impaling the rodent, and then the killed rodent is deposited in a container for subsequent removal. The killing of the rodent is done in a separate chamber so that no leftovers from the rodent or any ill smell is allowed to permeate into the feeding chamber, so that subsequent rodents approaching the feeding chamber are not discouraged from entering into the interior.

Abstract: A fly trap gun is provided with a fly trap carried on the end of a firing rod mounted for longitudinal movement within a barrel. The fly trap defines a trap chamber provided with a sticky area throughout a substantial portion thereof for catching flies or the like trapped therein. An actuating means causes the firing rod and the fly trap mounted thereon to move rapidly from a loaded position to a fired position for trapping a flying insect in the trap chamber and for subsequently catching the trapped insect on the sticky surface.

Abstract: An action play toy which includes a housing having a plurality of apertures therein and a plurality of action elements and three dimensional elements which are detachably received in the apertures. A gear assembly in the housing interconnects the action elements for simultaneous rotation and a bell assembly in the housing produces interesting sound in response to rotation of the gear assembly. The toy is adapted for assembly by a child with action and three dimensional elements of a variety of configurations, as desired.

Abstract: An interchangeable and stationary grinding wheel dressing structure mounted on a cantilevered base unit having the grinding wheel carried to it for dressing.

Abstract: A wafer workpiece polishing temperature control method and apparatus are provided wherein wafers are mounted upon a rotatable pressure plate assembly positioned in rotatable contact with a turntable assembly supported polishing pad, the turntable assembly having internal fluid cooling means, the wafer polishing temperature control being achieved through responsive closed loop electromechanical means activated by variation of polishing pressure upon the wafers and the polishing pad.

Abstract: A knife sharpener, comprising a sharpening rod mounted in a base, includes a first expandable position for storage as a compact unit.Wing members project laterally from a central member to provide stability during use, but are retractable into a cutout in the central member for compact storage. The wing members are drivingly connected to a support block for mounting the rod, so that when the wing members are positioned for use, the rod is rotated to an upright position. However, when the wing members are retracted, the rod rotates to a horizontal position, within a recess in the central member, for storage.The knife sharpener includes a rod mounting assembly comprising a sleeve, having a diameter larger than the rod, to permit the rod to be inclined, in any direction, at a predetermined angle relative to the sleeve. This predetermined angle is adjustable by rotating a plug, threadedly mounted in the sleeve.

Abstract: The present invention is a passive diversionary fluid collecting and debris separating apparatus consisting of a surface having an opening and the opening has a first and second downwardly extending fin disposed at an upper and lower edge respectively for channeling fluid for collection, downwardly extending intermediate fins for channeling fluid for collection disposed between and with means connected to said first and second fins and a membrane disposed across the opening for separating debris from the fluid.

Abstract: In combination, a vertically slotted panel wherein the vertical slots provide a constricted throat entrance and an internal enlarged pocket to captivatingly nest a keeper which is sized and arranged for limited rotation in the pocket into and out of locking engagement with the side walls of the pocket and which constitutes a clamp member by reason of a screw extending through it and through a force distribution plate sized to overlay the throat margins and from which a support arm extends perpendicularly to the panel so that it is adapted to be tightened into clamping relation in any of a wide variety of locations on the panel by means of screws.

Abstract: A suspended roof is described, which mainly consists of a cable rope structure (20-27; 31-33, 35-37; 39, 40) coverable with a stiff weatherproof material. By the special way according to which the cables are led, passing over fixed mountings (8, 9, 10, 11) and/or other points-of-change-of-direction (8, 9, 10, 11; 28, 30, 37, 38), equalizing the tension in different cable parts (20, 21; etc.), together with the use of a minimum of stiff compression members (31; 43; 47) to form stiff girders after having tensioned the cable ropes to the design tension, a suspended roof is obtainable which is as stiff as a conventional stiff-girder-roof-structure. As a result a classic stiff roof covering may be applied to it. The ground plan coverable may have any shape, and need not be symmetrical.The described roof structure is stiff in contrast to the generally adopted tent-type suspended roof structure built from cable rope which is basically flexible.

Abstract: A grain elevator utilizing pre-cast concrete elements includes a plurality of vertical zone rows of bins, which slope from front to back at an angle of approximately 30.degree., the front ends of the bins being located above office, receiving, grain cleaning or shipping and agro-product warehouse space; a tower or cowl at the front end of the elevator housing bucket elevator heads and distribution conveyors for loading the bins; a discharge manifold for removing the grain from the lower, rear ends of the bins, and conveyors for delivering the grain to trucks or to bins for feeding the grain into railway cars.

Abstract: A full height partition wall system is characterized by a unitary panel with a vertically movable head panel and a vertically movable foot panel secured thereto and forming a part thereof adapted to be moved upwardly and downwardly, respectively, to secure the panel to and directly against a ceiling and floor, respectively. The system has no posts, but rather a narrow vertical on each end of the panel which has an outwardly directed relatively shallow channel at the top in which is positioned a strut supporting the corresponding end of the head panel. A drive in the form of a small cog is operative vertically to move the strut and thus the head panel, with a spring detent member holding the strut in adjusted position. An adjustable foot is secured to the bottom of each vertical and the foot panel is spring loaded against the bottom of the foot for movement either with the bottom of the foot or movement independently against the spring loading.

Abstract: A horizontal force resisting building structure having a steel building framework, a bearing wall member being placed outside the building framework so as to face a suitable structure plane of the framework, and an attachment for attaching the wall member to the framework. The attachment has less resistance to plastic deformation than the wall member, and may include a bracket and a connector for connecting the bracket to the wall member.

Abstract: A thermal barrier is provided that includes a pair of sheets made of a material such as suitable plastic, and wherein the pair of sheets interfit to form a hollow panel. Compressible cellular foam material is mounted on the outer edges of the panel. Ambient air is adapted to be removed from the interior of the panel, and dry air or inert gas is adapted to be introduced into the hollow panel. Angle clips are provided for helping to maintain the barrier in its proper assembled position.

Abstract: A composite structure window belt has a roll of the lined reinforced plastic window frames set between honeycomb core and covered top and bottom with a reinforced plastic cover. The window frames have built-in reinforcements to accept fasteners for securing windows within the diamond-shaped openings.

Abstract: A modular beam/column construction having a tension member securing end caps to the opposite ends of the beams and columns which are placed in compression. In one embodiment, the end caps mounted to horizontally extending beams are in turn secured atop a base plate with a threaded fastener controlling the positioning of the beam ends relative to the base plate. In another embodiment, a cap mounted atop wooden beams is secured to a base plate by a tension member. The cap includes vertically movable adjustment members to horizontally level the cap although the columns are of different lengths.

Abstract: An insulative roof structure for application to a roof deck comprises a rigid foam panel having an upper surface and a longitudinal groove opening onto said upper surface. A rigid elongated strip having an upper surface is positioned within the groove with the strip upper surface being generally flush with the panel upper surface. A kraft board lamina including barrier means is bonded to the panel upper surface. A mechanical fastener extends through the lamina, the strip, the panel and into the deck for retaining the panel against the roof deck. A weather resistant membrane is adhesively bonded to the lamina.

Abstract: Tiles are mounted on a substrate by an adhesive strip of material having a backing member mounted thereon. The strip is first adhered to the substrate and subsequently, a facing tile member is affixed to the backing member. The means for joining the tile and backing member comprise an aperture in the middle of the backing member to receive a prong which projects from the back face of the decorative tile. A raised geometric configuration on the front of the backing member engages the mirror image geometric shape on the back face of the tile to prevent rotational misalignment.

Abstract: Elongated siding panels formed from plastic have integral joint portions along their side edges which are adapted to fit together and interlock when the panels are mounted on a building wall in overlapping relation. A flange adjacent the top edge of the panels extends outwardly and downwardly to define a channel open at its bottom, and an upwardly directed lip on the bottom edge of the panels is adapted to project into and interlock with the channel on a panel mounted therebelow on a building wall. A plurality of inwardly directed protrusions, or dimples, are formed on the upwardly directed lip to provide an interference fit with entrance to the channel.

Abstract: The specification describes a bricking ring for use in positioning and temporarily retaining bricks in a circular overhead configuration. The bricking ring intended for use in lining kilns comprises a plurality of arcuate segments forming a semi-circular configuration. The segments are pivotally interconnected, and are attached to a central rigid support by means of arms the length of which is adjustable. Thus, the radius of the semi-circular configuration may be adjusted so that the bricking ring may be used in different diameter kilns or when the kiln is lined with a double layer of bricks.

Abstract: A method and apparatus for rejuvenating worn or used balls, e.g. balls used in the game of racket ball by subjecting such worn or used balls to steam heat while confining such balls to a closed environment. The apparatus comprises a container, such as the can in which such balls are normally marketed and connecting thereto the outlet of a steam generating device whereby the balls normally stored in the container are subjected to steam heat generated with the steaming device.

Abstract: An automatic packaging machine comprises a slide vertically sliding along a stationary load bearing column and provided with horizontal rails wherealong a power driven carriage is movable carrying a packaging foil web supply device for laying a top horizontal sheet onto a parcel or pile to be packaged.

Abstract: A continuous packaging machine is comprised of two opposed pairs of conveyors arranged to define an elongated passage having a rectangular cross section for the passage of a hollow packaging tube. The four belts are synchronized and run in the same direction. A plurality of first forming devices and a plurality of complementary sealing and crimping devices are alternately disposed on a first pair of opposed conveyors and a plurality of second forming devices and a plurality of shaping plates are alternately disposed on a second pair of opposed conveyors. As the tube is fed downwardly through the passage, the tube is crimped and sealed, the first and second forming devices and the shaping plates engage the tube while it is being filled to define a rectilinear prismatic package and the tube is then crimped and sealed by the next pair of devices to define a closed filled package. Cutters may be provided with the sealing devices to separate the closed packages.

Abstract: A cutting tool for use in conjunction with the propeller assembly of a boat to prevent underwater foliage from fouling the drive mechanism of the boat. The shank end of the tool is secured to the motor housing and supports the cutting blade end thereof in close proximity with the propeller hub. As the hub rotates, underwater foliage encountered by the propeller assembly is swept into contact with the cutting edges of the blade whereupon the foliage is cut and the cutting thrown away from the motor.

Abstract: The header of a combine harvester comprises a conventional forward gathering portion and a feeder house portion which contains elements for processing crop material as well as transferring it from the gatherer to the body of the combine. A threshing cylinder and concave combination receives crop material from the discharge opening of the gatherer and delivers that portion passing between the cylinder and concave to a first separating conveyor extending downstream from the concave, within the feeder house. A simple conveyor underlies the concave and first separating conveyor, to receive grain and chaff passing through the concave and also that passing downwards from the first separating conveyor and delivers it to the body of the combine, for transfer to a cleaning shoe. Material carried on the upper surface of the first separating conveyor is transferred to a second separating conveyor (straw walkers) in the body of the combine.

Abstract: An improved mounting means is provided for the driven pulley of a power lawn rake. The driven pulley has a through axial bore. The rotor shaft is received in the bore and extends therethrough. A central tubular hub is formed on the inner face of the driven pulley and has a pair of diametrically-opposed openings formed therein. A transverse pin is carried by the rotor shaft and has radially-projecting end portions received in the openings in the hub, thereby keying the driven pulley to the rotor shaft. A self-locking retaining ring is received over the extending portion of the rotor shaft and resiliently bears against the outer face of the driven pulley, thereby retaining the pulley on the rotor shaft.

Abstract: A rotary mower has an engine supported by an engine platform secured to a frame having wheels and a handle, the engine has an output drive shaft which has a cutting blade rigidly secured at its end, a counter-rotating housing overlies the blade and is rotated in a direction opposite to the blade by a transmission means, the transmission means has a drive pulley rigidly secured to the output drive shaft, a pair of idler pulleys rotationally supported by the engine platform, a driven pulley rotationally supported by the drive shaft, and an endless belt trained from the drive pulley through the idler pulleys to the driven pulley, the counter-rotating housing is rigidly affixed to the driven pulley.

Abstract: A stranding machine, particularly for making telecommunication cable, having a cage with feed reels, a take-up reel, and a back-rotation device which includes two eccentric discs journalled eccentrically with respect to each other in a rotatable guide ring. The discs have a plurality of corresponding bores in identical patterns, each pair of corresponding bores having an eccentric shaft journalled in the two bores so that eccentric motion of the discs causes the eccentric shafts to rotate. Each eccentric shaft has a bore for feeding a wire strand through it and a clamping member which rotates with the eccentric shaft for imparting torque to the strand, by driving the guide ring independently of the discs, so that back-rotation can be varied.

Abstract: Method and apparatus for the production of fancy yarns from falsely twisted core and fancy threads. Staple fibers are drafted by a cylindrical drafter; the core and fancy threads are false twisted by a hollow spindle. At least one drafting of staple fibers are supplied upon the falsely twisted core and fancy threads by means of a pneumatic transporting channel. The speed of the fibers constituting the fancy threads is greater than the peripheral speed of the rollers delivering the core thread. If desired, two rovings of staple fibers may be used, the two rovings having different titre in a ratio of 1:10 and having different lengths of the fibers in a ratio of above 1:2, both rovings entering from one drafter, the two rovings after being drawn being supplied together to the combined false twisted core thread and fancy thread.

Abstract: An apparatus for stranding optical fiber cores while slackening the same in which optical fiber cores are pushed into core storing spaces which are to be twisted or twisted core storing spaces. A core delivering system has a passage for passing the optical fiber cores therethrough and a gas which flows from the back position of said passage towards the front position thereof functions to send out the optical fiber cores at the inlet side of said core storing spaces. The tensile forces of the optical fiber cores at the inlet sides of the core delivering system are decreased by a winding drum mechanism.

Abstract: A bearing rail is provided extending along each side of the draw frame and spaced laterally from the outer edges of the double upper rollers. At the end of the each rail, in the area when the thread exits from the exit rollers, each rail is provided with two carriers, one of which is provided with a light source and the other which with a light receiving photo-cell. The light source on one side of the drawing frame is arranged in association with the thread being drawn adjacent the photo-cell on the other side so that the light source causes this remote thread to cast a shadow on the photo-cell adjacent to it. Similarly the light source on the other side, the thread remote from it and the photo-cell opposite it are also aligned. The shadow on each photo-cell produces an alternating current which is then independently fed to a circuit and switch means, housed at the inlet end of the bearing rail.

Abstract: An air nozzle, suitable for producing a fasciated yarn, having at least one jet in each of narrow and wide passages along the traveling direction of the fiber bundle. Each jet is directed to generate a vortex whirling reversely from that of the other passage. The twist imparted to the fiber bundle by the vortex generated in the wide passage is restrained by the vortex whirling reversely thereto in the narrow passage. As a result, circumferential fibers of the fiber bundle are less twisted relative to the core portion thereof. During the untwisting operation of the vortex of the wide passage, the circumferential fibers are entangled around the core portion with a twist corresponding to the difference from the core portion, thereby obtaining a well-fasciated yarn.

Abstract: A device for controlling the flow cross sections of several channels for gas flow tubes which interconnect combustion chamber portions particularly of ram jet engines comprises a polygonal rotary valve which is rotatably mounted adjacent the passages and has corner portions which move through paths which cyclically cover and open these passages. The valve is actuated by a drive which includes a drive motor and shaft which are mounted in an insulation body between the combustion chamber portions.

Abstract: An air/fuel ratio control system for use with an internal combustion engine, which includes a three-way catalyst arranged in the exhaust system of the engine, an electrical circuit operatively connecting an O.sub.2 sensor with fuel quantity adjusting means in a manner effecting feedback control of the air/fuel ratio of a mixture produced by the fuel quantity adjusting means and being supplied to the engine, in response to an output signal produced by the O.sub.2 sensor, and secondary air supply means for supplying atmospheric air into the exhaust system at a zone upstream of the O.sub.2 sensor. The secondary air supply means is adapted to operate only during open loop control of the air/fuel ratio.

Abstract: A carbon particulates cleaning device comprises a carbon particulates catching means, a fuel injecting means, a fuel retaining means for retaining the fuel injected by the fuel injecting means near the carbon particulates catching means, a fuel igniting means for igniting the fuel retained by the fuel retaining means, and a gas blowing means which blows gas for maintaining the fuel burning and applying the heat of the burning fuel into the carbon particulates caught by the carbon particulates catching means. The carbon particulates caught by the carbon particulates catching means are effectively burnt and eliminated by supplying gas which is heated due to the burning heat of the fuel ignited by the fuel igniting means.

Abstract: A carbon particulates cleaning device for use in a diesel engine of an automobile or the like comprises an exhaust gas main pipe, an exhaust gas branch pipe diverged from the exhaust main pipe, a carbon particulates catching member which is provided within at least one of the exhaust gas main pipe and the exhaust gas branch pipe, a valve means by which exhaust gas is selectively supplied into the exhaust gas main pipe or the exhaust gas branch pipe, a heating means which heats the carbon particulates catching member, a gas supplying means which supplies gas into the carbon particulates catching member when the carbon particulates catching member is heated and a control means which controls each operation of the valve means, the heating means and the gas supplying means.

Abstract: An exhaust gas cleaning system for an internal combustion engine is provided which has an exhaust system including a TWC catalyst. The exhaust gas cleaning system comprises a secondary air supply passage coupled to the exhaust system on the upstream side of the ternary catalyst for supplying secondary air to the exhaust system. A secondary air control valve is positioned in the secondary air supply passage for regulating the flow of secondary air therethrough. The secondary air control valve comprises a unitary valve casing, a valve passage in the valve casing coupled to the secondary air supply passage, and first and second control valves for separately opening and closing the valve passages. The first control valve is closed when the engine is decelerating and the second control valve is closed when the engine is accelerating or operating at high speed, thereby maintaining the TWC catalyst as a reducing atmosphere.

Abstract: An exhaust gas cleaning system for an internal combustion engine having an exhaust system leading to an exhaust port of an engine body. The exhaust gas cleaning system comprises a TWC catalyst disposed in the exhaust system for simultaneously cleaning HC, CO and NO.sub.X in exhaust gas flowing through the exhaust system. A secondary-air supply passage is connected to the exhaust system on the upstream side of the TWC catalyst and coupled to the atmosphere.

Abstract: A compressor, pump, or alternator apparatus is designed for use with a resonant free piston Stirling engine so as to isolate apparatus fluid from the periodically pressurized working fluid of the Stirling engine. The apparatus housing has a first side closed by a power coupling flexible diaphragm (the engine working member) and a second side closed by a flexible diaphragm gas spring. A reciprocally movable piston is disposed in a transverse cylinder in the housing and moves substantially at right angles relative to the flexible diaphragms. An incompressible fluid fills the housing which is divided into two separate chambers by suitable ports. One chamber provides fluid coupling between the power diaphragm of the RFPSE and the piston and the second chamber provides fluid coupling between the gas spring diaphragm and the opposite side of the piston. The working members of a gas compressor, pump, or alternator are driven by the piston.

Abstract: A simple single wire nitinol engine including a pair of levers, one of which reciprocates with respect to the other and is connected to a crank shaft by a connecting rod to transmit rotational energy from the reciprocating motion of the lever. A spring wound single nitinol wire is connected to the ends of the levers and a means is provided for immersing the wire alternately in hot and cold temperature baths.

Abstract: The invention relates to a temperature responsive control assembly which uses the volumetric expansion of a substance having a high coefficient of expansion, to expel a piston from a cylinder, such movements of the piston relative to the cylinder being used to control relative movements between first and second load elements, such as for example a window and a window frame, with the cylinder being connected to the first load element and the piston being connected by way of a high leverage operating linkage with the second load element, and wherein the thermally expansive substance is located in the cylinder between end plugs and the piston passes through one of the end plugs there being shaft seal means carried by the end plug and sealing around the piston passing through it, the piston having its inboard end immersed in the thermally expansive substance.

Abstract: A brake booster for automotive vehicles comprises a low-pressure casing sealingly subdivided into a low-pressure chamber and a working chamber by an axially movable wall. The two transverse end walls of the low-pressure casing are interconnected by a central reinforcement tube integrally formed with a master cylinder. The actuating piston of the master cylinder is connected to a guide piston which is guided in the reinforcement tube and which receives a rubber-elastic reaction disc in an end thereof remote from the master cylinder. A control valve casing is axially movable in the reinforcement tube, bears axially against the reaction disc and is connected to the movable wall by radial ribs extending radially through longitudinal slots in the reinforcement tube. The radial ribs are connected to a ring which encompasses the reinforcement tube and which is secured in a bowl-shaped hub member of the movable wall.

Abstract: A power plant for exploitation of the temperature difference between different water layers in a pelagic area (2), comprising a closed system which is filled with ethane which is both in the liquid and vapor phases. The system comprises two heat exchanging apparatuses (13, 9) which are in fluid communication with each other, of which the first (13) supplies heat to the ethane by means of heat exchange with water from a relatively warmer water layer, while the other (9) removes heat from the ethane by means of heat exchange with water from a colder water layer, whereby a difference in pressure is created in the system which is utilized to take energy out of the system. In order to make the system large enough and the ethane pressure high enough to give a reasonable power yield, the heat exchanging apparatuses are placed in respective chambers (5, 4) which are comprised by cavities in solid or consolidated rock (1).