Abstract: A tire repair patch having overlapping plies of reinforcing cords, a base cushion gum layer and an intermediate cushion gum layer positioned between at least two of the plies. The intermediate cushion gum layer has a thickness greater than the thickness of the plies and suspends some of the plies for distributing the forces transmitted through the patch at the injured portion of the tire.

Abstract: An adjustable vehicle screen utilizes a telescoping frame having a slot disposed in the innermost surface thereof so as to permit an elastic-like screen member to have the marginal edges thereof pass therein. The free edges of the screen are captured within the tubular telescoping frame. The frame may be dimentional so as to accommodate various window openings in motor vehicles by allowing the screen to expand or contract in size in conformity therewith. One embodiment of the invention utilizes a pair of hinges joining together a pair of U-shaped frame members so as to permit the screen element to be folded up when not used. Such U-shaped frame members each have telescoping components thereby permitting the apparatus to adjust in size for various window openings. A portion of the frame is provided having a protrusion extending outwardly therefrom so as to be installed within the groove located in the frame of the vehicle in which the uppermost edge and the side edges of the window may reside.

Abstract: An apparatus and method for removing tie bars from a die casting machine. The apparatus and method involves utilizing gearing attached to the tie bar nut whereby the nut is held captive, but is capable of being rotated by an auxiliary drive unit. Further, by utilizing the existing die casting machine functions, it is possible to remove the tie bar from the machine so that the die can be removed and a new die inserted into the die casting machine. By reversing the process the tie bar can now be reinserted into its operating position in the machine and the locking nut rotated to its proper position and locked up.

Abstract: A method of producing a heat exchanger in which a fin block of porous metal and fin plates connected to the fin block are unitarily secured to a serpentine heat-transmitting pipe. A plurality of fin molds produced with the use of plastic patterns formed therein with continuous, three-dimensional cavities are assembled with the heat-transmitting pipe shaped beforehand into a serpentine form in such a manner that the fin molds enclose the heat-transmitting pipe with suitable spacing intervals defined between the fin molds themselves and between the fin molds and the heat-transmitting pipe. Molten metal of high thermal conductivity is cast into continuous cavities in the fin molds and into the spacing intervals, and the material of the fin molds is removed after the molten metal has solidified.

Abstract: Defined shapes of thin metallic sheet are continuously formed by forcing molten metal onto the surface of a moving chill body under pressure through a slotted nozzle located in close proximity to the surface of the chill body. The surface of the chill body whereon the shaped parts are formed is provided with raised or lowered domains corresponding in outline to that of the desired defined shape. As the metal is cast, as a thin sheet against the chill surface, discontinuities arise in the sheet at the walls of the raised or lowered domains defining the desired shape so that sheet product of defined shape is obtained, as if punched out from a continuous strip of the metal.

Abstract: An electromagnetic casting process and apparatus utilizing an active transformer-driven copper shield. The shield is actively driven with a voltage out of phase with the voltage in the containment inductor with the result that a bucking current is produced in the shield which is out of phase with the current induced in the shield by the inductor. An active transformer-driven duplex variable impedance shield is also disclosed.

Abstract: An improved cooling system for continuous casting through means of a hollow cylindrical die through the top of which molten metal is poured and from the bottom of which emerges a continuously cast bar conforming to the internal configuration of the die. The cooling system includes a cooling sleeve surrounding and continuously engaging the external surface of the die to withdraw heat from the die. The external surface of the cooling sleeve is provided with a series of grooves arranged in a continuous spiral or helix to increase the surface contact with a coolant which is circulated from an inlet upwardly along the cooling sleeve, as well as downwardly along the cooling sleeve to also contact the bar which is cast as it emerges from the die. Surrounding the cooling sleeve is a jacket and the space between the cooling sleeve and the jacket is divided by a partition to direct cool water which may be used as the coolant.

Abstract: A thermal energy storage apparatus and method in which containers holding a salt hydrate heat storage material are rotated by convection currents created in a bath liquid surrounding the containers, thereby increasing the life of the heat storage material without having to supply energy for an externally located rotating means. More specifically, an enclosure for a bath liquid is provided, the enclosure containing two vertically-extending baffles which together define a column of bath liquid in which the heat storage containers are rotatably mounted. A heat transfer means is provided at the bottom of the column between the two baffles and a heat removal means is provided at the top. As heat is transferred to the bath liquid, a convection current is created which in turn rotates the containers while heat energy is being transferred from the bath liquid to the salt hydrate material.

Abstract: Fresh, outside air may be supplied to a first space, such as a dining area of a restaurant or the like, while air from the first space may be recirculated through an air conditioning unit for cooling or heating the air, which is returned to the first space. Also, air from the first space is transferred to a second space, such as a cooking room of a restaurant or the like, which contains heat producing cooking equipment, the latter resulting in the second space having additional cooling requirements. Such transfer air is passed through a chilling device, in which the air contacts water, as through sprays or a water bath, to cool the water to a temperature close to the dew point of the air, and also to correspondingly cool the air furnished to the second space. When cooling of air to the first space is required, either the recirculated air, but preferably the fresh air, is cooled by the chilled water produced by the chilling device.

Abstract: A food service device including a food-carrying cart which can be stored inside a refrigerator is provided with elements for heating the food before meals are served. The electrical system is comprised of switching devices which actuate the heating elements depending upon the presence and orientation of food trays on the shelf of the cart; a self-aligning coupling which can supply electrical power to the cart's heaters when the cart is placed in the refrigerator; and a timer which controls the duration of time the electrical heaters are energized to warm the food prior to service, and provide a keep-warm timing sequence for holding the heated food within a refrigerated environment.

Abstract: A building heating and cooling system which eliminates the need for a dual circuited condenser in a water to water heat pump. The system includes a cooling tower water circuit, a device for cleaning and treating the water in the cooling tower water circuit, and a hot water circuit in the building. A single circuit condenser and a refrigerant compressor are used to heat condenser water. Apparatus is provided to inject the heated condenser water either into the hot water circuit or to the cooling tower. The heat pump also includes a cooler to provide a source of low temperature heat from a chilled water circuit in the building.

Abstract: A U-tube heat exchanger for the heat transfer from a primary gas circuit to a secondary gas circuit in a high temperature reactor. At the high temperatures of approximately 950.degree. C., the additionally permissible stresses on the used materials are low. The cold gas collector is therefore flexibly attached at the housing. The arrangement permits complete and also remote-controlled testing from the secondary gas-side of all parts of the primary gas circuit which are stressed by pressure. The flexible elements are neither stressed by the weight of the heat exchanger nor endangered by high temperatures.

Abstract: A heat exchange apparatus is illustrated, which may be used as in a stream of solar heated air for heating flowing water, wherein an array of heat pipes is utilized in heat exchange relation with a manifold, wherein vapor medium is exchanged therebetween for conducting heat from one to the other.

Abstract: A structure of fluid condensing and heat conducting surface of the condenser characterized in that completely recessed grooves for collecting fluid are provided on said surface integrally therewith, wherein the distance between the centers of radii of rounded corners of said groove is made less than 3 mm.

Abstract: A system for supporting a bundle of tubes against lateral movement in a heat exchanger, such as a nuclear power plant steam generator, wherein spring collar devices positioned at intervals along the tubes permit lateral movement of the tubes but prevent any relative movement between the tube and its associated spring collar device. Any lateral movement is between adjacent spring collar devices. With this arrangement, fretting and corrosion between the outer surfaces of the tubes and their lateral support members are substantially eliminated.

Abstract: A heat-exchanger element of the type consisting of two sandwiched metal sheets, deformed so as to define between themselves a flow channel, has a number of apertures in the portion of the element not deformed. The one heat-exchanging fluid passes through the channel and the other through the apertures, generally in a direction perpendicular to the sandwich interface. In a preferred embodiment the apertures are formed by a punching operation in the way that tongue-like flaps are formed which affect the direction of flow, create turbulence and may serve as means spacing or supporting adjacent elements.

Abstract: A duct-forming device is disclosed for use in a well completion apparatus of the kind, wherein a bore hole casing is positioned in a bore hole and duct-forming devices of alkali- and acid-resistant metal--such as steel--are secured at spaced levels to the casing in alignment with holes machined in the casing wall. In accordance with the invention, a closure device is arranged within the duct-forming device which permits flow of predetermined amounts of liquid, such as acid, from the interior of the casing through the duct-forming device and into the producing formation, while gradually being moved by the liquid into a position in which such fluid flow is prevented.

Abstract: The invention provides an improved method and apparatus for effecting the setting of a whipstock in a desired angularly oriented position in a well conduit solely by the use of a wire line but can be set on tubing or drill pipe, if desired. A packer is provided which can be expanded into sealed engagement with the casing at a desired location. The packer is provided with a key element, either a key or a key slot, and orienting elements by which a conventional well bore survey can provide an accurate indication of the angular alignment of the anchor key element. A whipstock anchor is provided incorporating a socket portion in which the whipstock may be rigidly secured and a shaft portion which is insertable within the bore of the packer and has a key element cooperating with the keyway, or key, provided in the packer. After setting of the packer in the well conduit, a survey is made to provide an accurate indication of the angular position of the packer keyway or key.

Abstract: A well bore packer which is run into a well casing on a tubing has actuator means responsive to applied fluid pressure to set anchor slips and to force a packing into engagement with the casing. The setting force is locked into the packing by a pressure balanced piston element having locking engagement with an inner body mandrel by a shear ring. A releasing tool is insertable within the bore of the body mandrel and incorporates an atmospheric pressure chamber. An operating mandrel for the releasing tool is shiftable through an increase in tubing pressure to establish communication between one side of the locking piston of the packer and the atmospheric chamber of the releasing tool, thus permitting the locking piston to shear the locking ring and free the setting forces operating on the packing elements of the packer.

Abstract: A thermal recovery system for a subterranean well includes an electric heater located immediate the bottom of the well which cyclically receives electric power generated at the well surface. A pump directs a stream of pressurized fluid, such as water, through a conduit to a solenoid valve located at the bottom of the well. The solenoid valve senses electric power application relative to the heater and directs the stream of pressurized water to one of two fluid circuits. When electric power is supplied to the heater, the solenoid valve directs the fluid stream into the heater. The heater thermally stimulates the well and is cooled by the water which is heated and exhausted to thermally stimulate the well. When electric power is not supplied to the heater, the solenoid valve directs the pressurized water to a turbine for driving a production pump. In an alternate embodiment, both the heater and the production pump are operated continuously and the fluid stream is divided between the turbine and the heater.

Abstract: A system for cleaning perforations in a well bore where the perforations are located below a packer means on a production tubing. A tool on a string of pipe has packer means for sealing off the cross-section of the production tubing and the pressure in the annulus between the string of pipe and production tubing is reduced. The tool has a bypass passage across the packer means which opens upon the reaching of a predetermined pressure across the packer means and the high volume pressure from the earth formations suddenly flows through the tool and cleaning of the perforations is effected.

Abstract: A waterproofed explosive charge is suspended within a frangible, spherical shell containing an aqueous solution. The assembly is dropped from an airplane or helicopter towards a fire below. Either a shock-actuated percussion cap or a fuse-ignited detonation cap activates the explosive charge at the appropriate moment and the resultant explosion creates a vapor-like fog. A portion of the combustion-supporting oxygen is displaced by the fog droplets. The minute water droplets also absorb heat energy, thereby lowering surrounding air and fuel temperatures. These effects, coupled with the concussive shock wave, act to snuff the fire.

Abstract: A soil working machine, such as a cultivator, has a frame beam to which a working element is connected by a support. The support is resilient or resiliently mounted and can deflect when the working element meets an obstruction, or heavy ground resistance, but the working element maintains its orientation in the soil. A control rod coextends with the support and four pivot points enable the element to be displaced without loosing its orientation. The working element is pivotally connected to the support by a pivot pin and the control arm also can be pivoted to that element. In a variant, the control arm is eliminated and a V-shaped share is hinged to pivot up and down between stops.

Abstract: An oscillator for reciprocating tools or other devices. Driving sprockets are mounted for rotation on a frame or in a housing and a pair of driven sprockets are mounted on the frame, each to be driven by a respective driving sprocket. The driven sprockets are outwardly of the driving sprockets, all sprockets having their axes in the same plane. Eccentrically mounted masses are on the shafts of the driven sprockets which when rotated generate forces on the axes of the driven sprockets. These forces are transmitted to the frame through shafts of the driven sprockets. A couple is generated about the axis of the driving sprocket causing the frame to oscillate. A tool attached to the lower end of the frame is thereby reciprocated.

Abstract: A drilling head includes a tubular body with top, bottom and side openings.A top closure closes the annulus between a portion of the head above the side opening and a drive tube such as a kelly extending through the head. The top closure includes a rotor, adapted to form a non-rotating seal with the kelly, and a stator, with a rotating seal between the stator and rotor. The stator is supported on and releasably connected to the body. The rotor includes a seal tube rotatably supported by inboard bearings on the stator located above the rotating seal.The seal tube has a replaceable rubber stripper to seal with the kelly. An upwardly flaring medial flange on the stripper guides upwardly flowing annulus fluid toward the side opening and away from the rotating seal.The rotor includes an elastomer sandwich drive bushing, rising above the stator into the rotary table, splined to the seal tube and secured to the kelly by slips.

Abstract: For use in a drilling string, the preferred and illustrated embodiment depicts a drill collar to be placed in the lower parts of the drill string for straightening the hole. The preferred embodiment utilizes a generally square drill collar with a thick or heavy wall. It is square in cross section along the greater portion of its length, the four corners being slightly rounded to a specified diameter on rotation, and the four lengthwise corners of the regular cross section are all reinforced with hardfacing material to a specified depth, typically tungsten carbide. The four edges abrade the bore hole as the drill string penetrates the earth. In addition, the lower end of the tubular body includes lengthwise flutes in the form known on a stabilizer to guide the hole straightening device into the hole to be reamed by operation of the device.

Abstract: Device for use in the drill string used to drill an oil well. The device has a cylindrical body, four passageways located lengthwise through the cylindrical body, and a Y-shaped bottom member, which has a Y-shaped passageway therethrough. The two upper arms of the bottom device communicate with two oppositely-located passageways in the cylindrical body. Such Y-shaped passageways communicate with the bottom portion of the drill pipe. A top stem, which has a longitudinal passageway thereof and which has four side ports. Such longitudinal passageway communicates with the top portion of the drill pipe. A collar is rotatably positioned around the four ports of the top stem and is slidably removable from the top stem. The collar has two side L-shaped arms, with a passageway in each arm. Retainer means which is detachably positioned around the top of the top stem. The cylindrical body tightly and rotable fits within the well casing.

Abstract: A hybrid rock bit is disclosed which consists of a pair of cone cutters mounted to legs 120.degree. apart with an extended drag bit leg occupying the remaining 120.degree. segment. Several synthetic diamond stand-off type studs are strategically located and inserted in insert holes formed in the face of the drag bit leg. Nozzles are placed in front of the cutting face of the diamond studs to cool and clean the studs as the bit works in a borehole.

Abstract: An improved broach is disclosed incorporating, in the preferred and illustrated embodiment, an elongate tubular member constructed in the fashion of a drill collar having a raised external thread cut thereon in helical fashion, the thread having a top face. The thread tapers from the bottom to a maximum diameter at a very gradual rate. The top face includes a generally flat, exposed surface which is reinforced with particulate tungsten carbide. It additionally includes inserts of tungsten carbide at periodic locations as, for example, inserts located at ninety-degree intervals along the thread face. The inserts extend relatively deep and are constructed of a solid block of tungsten carbide in a supportive alloy. Another form has inserts made of cylindrical pellets.

Abstract: An electronic weighing apparatus comprises a load cell which provides an analog voltage associated with the weight of an article being placed on the apparatus. The analog voltage is converted into digital data responsive to each timing pulse by means of an analog/digital converter. The digital data is loaded in a digital display buffer responsive to each timing pulse and is then displayed in a digital manner by a display. On the other hand, a stable state detecting circuit compares the current digital data obtained from the analog/digital converter with the preceding digital data and determines the weighed value having reached a stable state upon coincidence of both the current and preceding pieces of the data. The timing pulse and thus the digital data is prevented from being loaded in the display buffer responsive to the output from the stable state detecting circuit, whereby the display buffer continues to maintain the digital data at the time point when the stable state is reached.

Abstract: Scale protected against ingress of dust and water in which elements of the scale which are always present in any scale are combined with extremely simple additional mechanical means in order to achieve the desired protection, comprising a measuring system, a frame, at least one foot supporting said frame, a load support, guiding means for parallel and vertical guiding of said load support, at least one opening having an inner edge in said load support for said foot, an annular diaphragm mounted between said foot and said inner edge, said load support enclosing completely said measuring system, said frame and said guiding means.

Abstract: The invention relates to a load receiver comprising an upper plate 10 and lower plate 11, and a weighing mechanism located between them.The weighing mechanism is made of two half-beams 12 and 13 supported on pieces 128 and 138 hinged on one side with respect to the upper plate 10 and on the other side with respect to the lower plate 11. Connected at their center by an elastic strip 14 having a constriction 140, these beams receive a flection related to the load. This flection is transferred by arms 15 and 16 to electrodes 151 and 161 forming a capacitor. By measuring the capacity of the capacitor, the weight of the load is obtained. The invention is of use notably for flat bathroom scales.

Abstract: A seal structure for an air cushion vessel includes an inflatable bag secd to the hull and a plurality of juxtaposed, interconnected planer members maintained in operative position beneath the bag by a plurality of support straps. Each planer member includes a transversely reinforced shell portion and a flexible, resilient membrane secured to the longitudinal edge portions of the shell portion to form a flexible planing surface for the seal structure. The planer members may have tapered aft end portions and curved planing surfaces to provide a gradual change of the interface between the planer members and the water.

Abstract: Apparatus for controlling a release of pressurized fluid, to generate an acoustic or shock wave impulse for use in underwater reflection seismic surveys. Compressed air is supplied to the acoustic impulse generator and is used both to provide the compressed air acoustic impulse and to retain two piston members in sealing engagement with each other to maintain the compressed air within the apparatus. The two internal pistons are hollow, open-ended cylindrical members, and are adapted to slide axially within a cylindrical chamber and abutt one another to preclude escape of compressed air. To fine the acoustic impulse generator, compressed air pressure holding the first piston member in position over a series of exhaust ports is suddenly reduced, causing that piston to shift within its chamber, exposing the ports to atmosphere and thereby emitting an acoustic impulse of compressed air.

Abstract: A wheelchair lift device located in the stepwell that includes foldable hinged members normally positioned through a linkage to form upper and lower steps with a riser therebetween, and rotatable outwardly relative to the stepwell during which time the steps are aligned along a horizontal plane to form a platform for supporting a wheelchair and the riser is tucked under the upper step.

Abstract: A caliper guide for a floating caliper disc brake comprising guide grooves and projecting parts with either the guide grooves or projecting parts being elastically deformable under the action of the braking force to thereby break loose particles of corrosion or dirt present on the guide surfaces.

Abstract: PCT No. PCT/US80/00017 Sec. 371 Date Jan. 7, 1980 Sec. 102(e) Date Jan. 7, 1980 PCT Filed Jan. 7, 1980.This invention relates to a control system (8) for moving a frictional coupling between an engaged (15) and disengaged (17) position. A power device (40) is provided for moving the frictional coupling (18) to the engaged position (15) in response to a control device (26) being at a first position (27) and the disengaged position (17) in response to the control device (26) being at the second position (29). A switch device (70) deactivates the power device (40) at the engaged (15) and disengaged (17) position of the coupling and a maintaining device (60) releasably maintains the coupling at the engaged (15) and disengaged (17) positions. Thus the brake is held in the engaged and disengaged positions in the absence of electrical power. The control system (8) is particularly useful on a lift truck (18) parking brake system.

Abstract: In a riding mower having a clutch controlled belt drive and foot brake, linkage between the brake and clutch having lost motion insures that the clutch is disengaged whenever the brake is applied.

Abstract: An electromagnetic clutch device for torque transmission from an input means to an output means which incorporates an air gap adjustment feature between the pole faces and the armature during assembly of the clutch. The air gap adjuster permits the armature to be responsive to magnetic flux formed by a predetermined electromagnetic coil voltage without having to tear down the assembly if the predetermined coil voltage is exceeded at initial try-out. Means are also incorporated to compensate for wear of the torque transmitting material.

Abstract: An electromagnetic clutch comprises a pair of cup-like sheet metal housing members facing each other and overlapping at their respective outer peripheries to form a radial air gap. The housings are spaced from each other to form a cavity for receiving an electromagnetic coil. One of the housing members is adapted for installation on a drive shaft while a bearing is affixed with respect to the other housing member such that the housing members may rotate relative to each other. First and second spacers are uniquely positioned in combination with the housing members together with the bearing and the shaft to provide an axial air gap and to control the flux transfer area of the radial air gap.

Abstract: A clutch and variable ratio torque multiplier having an input shaft upon which a housing having a power output device is coaxially journaled A plurality of balls carried in a disc are rotatably driven by the input shaft and are free to move radially due to centrifugal force, with such rotational and radial movement of the balls taking place in an opposed pair of special axially biased races that are carried in the housing for rotation therewith. At idle RPM of the input shaft, the balls roll freely in the races and zero rotational output of the housing results, and as shaft RPM increases, centrifugal force moves the balls radially and frictional engagement of the balls and the races increases for rotatably driving the housing at ratios which vary with the input shaft RPM. As the ratio approaches 1:1, the races engage friction clutches to lock the housing to the shaft to prevent slippage at higher RPM.

Abstract: In a clutch disc assembly, a hub disc extends outwardly from a hub and a cover disc is provided on each side of the hub disc. The cover discs are angularly movable about the axis of the hub between a neutral position and a pair of terminal positions each spaced on an opposite side of the neutral position. Groups of aligned windows are provided through the hub disc and the cover discs with the windows extending in the circumferential direction around the hub axis. A compression spring extends in the circumferential direction about the hub axis and is located within each group of aligned windows. The compression spring functions as a torsion spring operatively interconnecting the hub disc and the cover discs for resisting angular movement from the neutral to the terminal positions. A plurality of friction units are located between the hub disc and the cover discs and the friction units have different torque values.

Abstract: An adjusting device for a spring loaded friction type clutch is incorporated, as a sub-assembly, in the lever system of the clutch between an actuating collar and an axially movable adjusting ring so as to be operable to permit the manual advance of the adjusting ring as the friction surfaces of the clutch wear, lock the adjusting ring to compensate for the clutch wear. The improvement being a locking device having support means secured to the clutch cover and means to engage radially extending teeth of the adjusting ring to suitably lock the same against rotation after adjustment thereof to compensate for clutch wear.

Abstract: A storage bin for plural articles, such as citrus fruit, comprises a housing having an opening at the upper extremity thereof for gravity feeding the articles into the housing. The bin includes a downwardly sloped baffle in the housing for breaking the fall of the article to prevent damage to the articles, the baffle formed of plural, parallel steps, each step being spaced from adjacent steps a distance which permits the articles to pass there between in order to fill the void underneath the baffle.

Abstract: A redemption apparatus or system and process for accepting the return of selected types of non-refillable containers, and issuing to the customer a cash return or a coupon redeemable at a store for the face value printed thereon. In one embodiment of the invention the redemption system includes an open round carousel turntable having circumferentially separated compartments thereon in which a customer places a returned bottle or can. The returned container is placed on the carousel with a code thereon, which may be of UPC type, facing radially outwardly therefrom such that rotation of the carousel results in movement of the code past a code reader within the redemption apparatus which scans and detects the code markings.

Abstract: A shirt card, formed of a unitary blank of paperboard, for supporting a shirt during transport and display. The shirt is secured to the card without the necessity of pins. The shirt card is foldable and is self-locking in the folded position. The card comprises a main panel, a central fold line separating the main panel into top and bottom sections, a collar receiving extension at the top edge of the top section, a pair of slits receiving the sleeves of the shirt, a second set of slits receiving the sides of the shirt, and a tab and slit locking mechanism to lock the main panel in the folded position. The collar receiving extension can have a pair of opposed wing flaps for fully supporting the collar. A clothes hanger is received in the body portion of the shirt to support the shirt card with the shirt attached thereto.

Abstract: A folded biodegradable cardboard dispenser for razor cartridges. The dispenser has a series of compartments each provided with a tear strip for selectively uncovering the loading channel and one end of a disposable razor cartridge packaged therein.

Abstract: A tape cassette security container including a housing having an entry opening of slightly lesser dimension than the cassette, a plug member limiting the space within the housing to prevent removal of the cassette, and a key member for removing the plug member to permit removal of the cassette.

Abstract: A skin package wherein an article is enclosed between layers of thermoplastic film joined by heat sealing around the perimeter of the article and including at one side a strip, enclosed between the layers and projecting from them, which is heat sealed to one layer only and is non-adherent or only lightly adherent to the other layer.

Abstract: A double layer inflatable bag for protecting a blade of an aircraft. The includes a puncture proof outer layer and a flexible inner layer joined together at the extreme ends to form an elongated bag. Means for inflating various sections of the space in between two layers are provided. The bag is put on over the blade and is inflated. Inner layer of the bag is in contact with the blade to keep it in position and the outer layer thereof protects the blade from damage.