Abstract: An elongated approximately C-shaped frame with a handle portion above an elongated hand hole has downwardly-projecting arms depending from its forward and rearward ends. The forward arm is bifurcated by being keyhole-slotted vertically into a pair of laterally-spaced L-shaped fingers which straddle the spike and the tubular spacer surrounding it within the gutter. The rearward depending arm is provided with an impact abutment for receiving hammer blows during use. A strengthening rib extending along the body between the depending portions imparts rigidity to the frame. In the first stage of its use, the forward depending arm is moved over the top of the gutter and dropped around the tubular spacer, then pulled toward the user until the flat ends of the fingers engage the inner surface of the outer gutter wall directly beneath the spike. A hammer blow on the abutment on the rearward arm pulls spike, spacer and gutter bodily a short distance away from the building wall to which they are attached.

Abstract: A method and apparatus for terminating optical fibres. In the method, the fibre is threaded through a tubular ferrule so that the end of the fibre projects from an end face of the ferrule, and a heated cutting edge is swept across the end face of the ferrule at a predetermined rate. This produces a cut end for the fibre with a minimum of scratches, roughness, distortion, stress or discoloration without the need for subsequent grinding or polishing. The apparatus disclosed is particularly intended for performing the above method and comprises a jig adapted to receive the tubular ferrule and a fixed heated blade. The jig is arranged to be movable freely under the action of gravity with the end face of the ferrule maintained in sliding engagement with the blade whereby the cutting edge thereof is swept across the end face at the predetermined rate.

Abstract: A cylindrical pressure vessel is placed under an inward prestress to resist outward forces by the application of outwardly spread annular stressing means which are then permitted to bear inwardly upon the vessel. The device includes fluid-pressure means for relieving the inward force during the application of the annular means so that at least one ring of the latter can expand outwardly and then contracted on the periphery of the vessel.

Abstract: The method of manufacturing an improved collapse-resistant corrugated hose of flexible elastomeric material including a tubular structure which preferably includes a single layer of textile reinforcement which may be of a knit construction. The tubular structure is formed to an outside diameter essentially that of the maximum diameter of the mold cavity then placed therein and vulcanized under heat and pressure to mold form cylindrical end portions and a corrugated central portion. A preformed wire insert is then placed in the troughs of the internal corrugations to provide resistance against collapsing when the hose is subjected to a vacuum or bending. The hose is particularly useful in automotive vehicle cooling systems.This application is a continuation of Ser. No. 504,228; Sept. 9, 1974, abandoned; which is a continuation of Ser. No. 353,151; Apr. 20, 1973, abandoned; which is a continuation of Ser. No. 166,138; July 26, 1971, abandoned.

Abstract: A watch case containing at least one opening, in combination with means for sealing said opening comprising a plate of circular material containing on one surface thereof a resilient disc shaped material with an edge having a concave outward shape. In a preferred embodiment the plate compresses a stainless disc and the resilient material comprises neoprene rubber.

Abstract: A tool magazine is provided wherein an endless chain carrying a plurality of tool sockets is guided on a magazine frame and is indexable to present to a removal station one of the tool sockets receiving a desired tool. An operating arm mechanism carrying a push rod is pivotably supported on the magazine frame. A foot-operated lever, pivotably carried on the magazine frame, is linked with the operating arm mechanism and, when trodden, causes the push rod to push out the desired tool from the one of the tool sockets. A locking device is further provided on the magazine frame for locking the operating arm mechanism each time the same is retracted to its original angular position after pushing-out of the desired tool. Thus, the foot-operated lever is prevented from operation unless the locking device is manipulated to release the operating arm from thereby locking.

Abstract: Apparatus for changing tools in a punching machine comprises concentric upper and lower turret magazines carrying tools disposed with their axes on concentric pitch circles. Guide means for successively moving the tools from the magazines to an operating position comprises fixed and movable guide portions having complementary guide surfaces for the tools. The fixed guide portion is outside the pitch circles of the magazines and the movable guide portion is movable between a first operating position in engagement with the fixed guide portion, a second changing positions in which the axis of its guide surface intersects the pitch circles of said magazines and a third neutral position inside the pitch circles so that the tools can pass between the fixed and movable guide portions when the magazines are indexed.

Abstract: A method of manufacturing a silicon gate MIS device providing automatic formation and alignment of the gate structure during formation of adjacent impurity regions. In a preferred embodiment, the process is for the gate structure and source and drain of silicon gate FETs. The layered gate constituents-- typically oxide and silicon-- are formed on a semiconductor wafer. A photoresist mask which is larger than the desired gate size is formed on the silicon and the silicon is etched to a predetermined size beneath the overhanging mask. A deposition mask in the form of the photoresist mask or the gate silicon oxide and which is of the same size as the photoresist mask, is used to control the deposition of impurities within predetermined surface areas of the substrate which are spaced a predetermined distance from the silicon gate boundaries.

Abstract: In a monolithic integrated circuit having a combination of bipolar and junction field effect transistors, a pulsed laser is employed to trim the transistors to achieve balanced circuit performance. The laser is applied to individual circuits in wafer form using a step and repeat operation. Each circuit is measured, the transistor to be trimmed determined and a first trim performed. The circuit is remeasured and, if still out of specification, retrimmed. The process is repeated until a desired degree of balance is achieved.

Abstract: In the manufacture of a monolithic light-emitting diode array, electrical isolation between the n-type regions of portions of the array, for example the columns of a matrix array, is effected by mechanically cutting channels between the portions, through the n-type region and the common electrode. This method of forming the isolation channels makes it possible to produce much narrower channels than can be achieved by chemical etching, thus providing a high resolution array.

Abstract: The invention provides a new method of making electric motor stator assemblies of the type comprising a magnetic stator body with a plurality of discrete poles and a coil wound on each pole. Preferably each stator assembly is made by (a) providing a flexible chain of hollow bobbins with terminal pins for each bobbin; (b) inserting a magnetic pole piece in each bobbin in turn; (c) winding a coil on each bobbin and attaching the ends of each coil to the terminal pins of the bobbin on which the coil is wound; and (d) inserting at least a portion of the bobbin chain in a casing which engages and provides a low reluctance magnetic connection between the several pole pieces, whereby a stator assembly is formed which is characterized by (1) a stator in which the casing acts as the stator body and the pole pieces act as individual stator poles, and (2) individual coils each associated with one of the stator poles.

Abstract: A magneto rotor is formed of a hollow cup-shaped cylindrical drum adapted to be mounted on the flywheel of a combustion engine. A plurality of discrete cylindrically segmental permanent magnets are angularly equispaced about the interior of the drum and radially overlying the inner surface of each of these magnets is a magnetically permeable pole piece also of cylindrical segmental shape. The gaps between each of the inductors formed by a respective magnet and pole piece are filled by nonmagnetic holding blocks having lateral flanks tightly engaging the magnets and pole pieces. An adhesive tightly secures the magnets, pole pieces and blocks in the drum. The arrangement is assembled by fitting in the holding blocks and magnets and thereafter driving the pole pieces tightly in place between the holding blocks.

Abstract: An ultra-thin hermetically sealed button-type electrochemical cell is disclosed comprising a pair of mating metallic housing members, at least one of which is generally dish shaped to define an enclosed space therebetween. A peripheral opening defining a fill port is formed in one of the housing members, preferably at the junction formed by the mating surfaces. The interfacing surfaces of the cell housing members are welded together subsequent to the insertion of the internal cell components and prior to the addition of the electrolyte to form a hermetic seal. The electrolyte may then be added and the fill port hermetically sealed by welding. Owing to its relatively small size, the fill port may be quickly sealed so that the heat generated during the weld process is insufficient to volatilize the electrolyte.

Abstract: An apparatus is disclosed for simultaneously terminating a plurality of insulated metallic conductors in the insulation-piercing contact members of a multi-contact connector. The apparatus includes a base which supports the connector in conductor-receiving position and a carriage which carries a reciprocating insertion tool. The carriage is pivotally attached to the base and moves between an open position and an operating position wherein the insertion tool is aligned with the connector. Locating means are mounted on the carriage in fixed spatial relation to the insertion tool to align the connector for the termination operation as the carriage moves to the operating position. Self-actuated latch means retains the carriage in the operating position and includes a release means which may be actuated while returning the carriage to the open position, all in a single operation.

Abstract: Apparatus for serially feeding and crimping a plurality of electrical contacts of the type having an open-ended, ferrule head portion adapted to receive an uninsulated end of an electrical wire and to be crimped into electrically conductive contact therewith. The contacts are serially discharged from an annular hopper and caused to attain an upright position. First and second tracks, mutually aligned and vertically spaced one from the other, are provided for transporting the electrical contacts, while in the upright position, from the hopper to a mechanism for feeding the contacts into a crimping chamber. The tracks have a downward inclination from the hopper which is insufficient to permit sliding movement of the contacts absent vibratory movement of the tracks, which movement is derived from a vibratory device connected to the hopper.

Abstract: The razor is of the type which has on its head a generally T-shaped fitting on which a conventional razor blade unit can be releasably mounted by urging the fitting into a correspondingly shaped channel or recess formed in the back of the blade unit. The blade unit can be removed from the head and stored in a generally rectangularly-shaped aperture formed through the razor handle intermediate its ends. An elongate rib is formed on one side wall of the aperture, and a cam lug is formed on the other side wall so that when the blade unit is forced into the opening the cam lug urges the channel of the blade unit releasably over the rib, thereby positively to hold the blade unit in the handle until forced therefrom by finger pressure or the like.

Abstract: A fork having a finger operated assist blade pivotally attached thereto such that it is movable sideways against the outer tine of the fork in a lateral direction. The assist blade, which is spring biased outwardly, is higher than the fork tines so that food will be pushed on the fork as it moves inwardly.

Abstract: A scraper assembly comprising a housing having a head portion adapted to receive and retain a blade unit, and a cover member adapted to cover the blade retained by the head portion, the cover member being releasably retained by engagement with the head portion and completely separable therefrom, the cover member being further adapted to cover portions of the housing remote from the head portion, the cover member being releasably retained by engagement with a second portion of the housing and completely separable therefrom, whereby the cover member may be selectively positioned to cover the blade unit and may be removed therefrom and positioned on the housing at an end remote from the blade unit to expose the blade unit for scraping operations, and may be completely removed from the remainder of said assembly.

Abstract: Following the making of a dental impression and the subsequent making of a denture plate, upper plate, lower plate or both, the remaining natural teeth are extracted and the gum or gums are incised along the dental arch. The skirt portions of the plate are placed in the incisions and the plate may be firmly anchored to the jaw bone with screws or the like. The gum flaps formed by the incisions are then sutured to the skirt portions of the denture plate with dissolvable denture material. The suture passes transversely through the gum tissue and gum flaps above the jaw bone and through receiver apertures provided in the skirt portions of the denture plate. The invention is adaptable to complete or partial plates, upper and lower.

Abstract: An adhesive composition is provided for the hard tissues of the human body which comprises (1) a radical-polymerizable monomer and a curing system comprising (2) a peroxide, (3) an amine (or its salt) and (4) a salt of a sulfinic acid. The composition is available in two independent packages, one of which contains (1) and (2) the other package (3) and (4). Alternatively, one package contains (1) and (3) the other package (2) and (4).

Abstract: This invention discloses an orthodontic unit disposition structure wherein a clinical area and a consultation area are provided in an adjacent relation with each other so as to carry out systematic and rational treatment and instruction from first to last whereby a patient can have his case initially diagnosed and then receive treatment and instruction, thus being enabled to undergo an effective operation.

Abstract: A honing stone attachment for a low-speed dental handpiece is described. The lock rod for the handpiece, which is used to close and open the chuck for receiving burs, is provided at its rear with a honing stone. Operation of the handpiece causes the honing stone to rotate, which makes readily available for the dentist a sharpening instrument for his tools.

Abstract: A dental handpiece which has a connecting fitting for attachment to a supply hose having at least one agent supply line, a head section having a compressed air drive motor, a grip portion extending between the fitting and head section and a passage in each of said head section, grip portion and fitting for compressed air and a separate passage in each of these for any additional desired agents, characterized by the grip portion having a tubular sleeve portion, which is connected to the head section and receives the passage for compressed air and any other passages for agents, if present, and means detachably connecting the grip portion to the connecting fitting and includes means enabling relative rotation of the sleeve portion to the fitting so that the sleeve portion and each passage of the head section are rotatable relative to the fitting and each passage therein.

Abstract: Procedure and device, through which it is possible to realize a three-dimensional and transparent representation of the crest of each plater mold, and then to displace this representation, while keeping it parallel to its original position, in a direction at least approximately perpendicular to the occlusal plane, thus translating to an occlusal level under a three-dimensional form, the characteristics of the anatomic conformation of the underlying alveolar crests. Therefore, even after the application of a wax mask over the plaster mold, we still dispose of a representation of the crest, so displaced by perpendicular translation as to leave free the space needed for the fitting of the teeth, and this representation will allow in every moment to select the position of the different teeth and to control the position assigned, singularly and collectively, to the teeth themselves.

Abstract: Endodontic files extend freely through openings in a gauge plate supported through a central threaded opening by an elongated, rotatable screw extending upwardly from a base. A post extends upwardly from the base and slidably engages the gauge plate to prevent rotation of the plate while allowing it to move vertically relative to the base upon rotation of the screw, whereby to afford adjustment of the vertical distance between the base and gauge plate to correspond with the depth of radicular pulp to be removed from the root canal of a tooth. Depth stoppers on the files are adjusted along the length of the files to bring them into abutment with the upper surface of the gauge plate, thereby establishing the depth to which the files are to penetrate the root canal. A cover fits removably over the gauge plate and base to retain the files on the gauge plate during transport and to accommodate autoclaving and sterile storage.

Abstract: The dental prophylactic right angle hand piece of the knob type includes conventional driving and driven members, with the driven member including an integral collar and an integral serrated knob to which the dental application or cup is releasably secured for preventing the cup from slipping under pressure. The collar forms an effective seal between the head of the hand piece and the cup to prevent bacteria from entering the interior of the hand piece. With such a construction the hand piece can be operated forwardly or backwardly without the cup slipping or falling out of the hand piece.

Abstract: A marking device is described which includes a guide post having a guide surface and inclined to the vertical plane, a horizontal arm carried by the guide post and movable up and down along said guide surface, a detector for detecting the material on which the marking is to be effected and carried by the horizontal arm, movable back and forth in the direction perpendicular to the material, a crosshead movable along the length of the horizontal arm, a marking head carried by the crosshead movable in the direction perpendicular to the direction in which the crosshead, is moved and a marking member carried by the marking head, movable in the direction perpendicular to the directions in which the crosshead and the marking head are moved, respectively.

Abstract: A drawing instrument for drawing an ellipse having two arms extending to left and right associated with operating mechanisms, so that when the arms are opened by a turning force of a first arm, a center moves along the straight line C, C' at a right angle to a straight line B, B' while maintaining two angles .theta. and .theta.', which are formed between the straight lines B, B' extending between centers of the bed seats or supports and left and right arms about the center, equal to each other.

Abstract: A gauging device for gauging tapered rollers or the like, comprising feeding means for feeding each roller to a gauging station, first and second lower knife edges or the like projecting upwardly at the gauging station for supporting each roller, an end knife edge or the like at the gauging station for engaging one end of the roller, and a gauging head having an upper knife edge or the like projecting downwardly at the gauging station for engaging an upper portion of the roller, the gauging head having biasing means for biasing the upper knife edge downwardly against the roller, and output or indicating means for producing an output corresponding precisely with the position of the upper knife edge. The feeding means may comprise a rotatable wheel having pockets therein for carrying the rollers to the gauging station. A chute may be provided to feed the rollers into the pockets in the wheel. The gauging device is preferably inclined so that each roller is biased by gravity against the end knife edge.

Abstract: A device for checking involutes and helix angles of cylindrical gears by electronically compensating for mechanical errors, which includes a mechanically operating transmission chain, especially a rolling transmission, a sine bar, a sliding block linkage and/or a lever transmission, which transmission chain guides a measuring feeler relative to a gear to be checked on the required reference curve. The device furthermore includes one length pick-up each at both ends of the transmission chain for measuring their respective motions, a computer unit for multiplying the signal of one of the length pick-ups with the put-in rated transmission ratio of the transmission chain and for subtracting the multiplied signal from the signal of the other length pick-up, and also includes a device for subtracting with the proper prefix + or - the thus formed difference signal as correction value from the measured value of the measuring feeler.

Abstract: An electrically responsive level of the type used for determining inclination with respect to a gravity field is described. The instrument relies for its operation on a bubble-within-a-vial type of inclination sensor. The vial is generally rectangular in cross-section, and its dimensions and the size of the bubble therewithin are selected to assure that the instrument can be used reliably in the field without false readings and the like. The specific leveling instrument described is of the so-called carpenter's type and is usable not only to provide a visual and/or audio indication of a level condition, but also to measure or establish any inclination between the horizontal and vertical.

Abstract: An irradiation unit, especially adapted to use as a printer's ink drier, having means for mounting an elongate irradiator in an enclosure. In one embodiment, the irradiator is arranged for pivotal movement to and from a work position within the enclosure by being supported in one or more sleeve bearings. In another embodiment, provision is made for a ventilation hood to guide cooling air flow predominantly across and/or about the end contacts for the irradiator tube and the ends of the tube.

Abstract: Lumber within a kiln is subjected to a multi-step process including initial dehumidification drying to a moisture content of approximately 12 to 20 percent followed by drying at a substantially higher temperature without dehumidification. The higher temperature drying step is continued until a moisture content of approximately 6 percent is reached, after which high humidity conditions are preferably introduced into the kiln for equalization and/or conditioning of the lumber.

Abstract: This application relates to a method for conditioning products that are stacked in containers which are partially open and in which there is disposed between two containers stacked one on top of the other and close to a side wall of these containers a ventilator unit to produce an air current in the gap between the containers and which extends into the partially open containers. The ventilator may be attached removably to the containers by suitable means and is provided with an inlet or outlet nozzle that has a height which corresponds to the gap between the containers.

Abstract: A washing machine having an outer tub, a perforate rotatable drum housed in the tub, and a timer for cycling the machine through a series of operating phases. The tub has an opening and a housing affixed to the outer surface of the tub such that a space adjacent the tub opening and communicating with the tub is provided. Ultraviolet lamps are positioned in the housing, a door is located on the housing for sealingly closing the tub opening, and the door is controllable between open and closed positions. The timer controls opening and closing of the door so that items in the drum may be irradiated.

Abstract: An entertainment and/or educational device is proposed which comprises a housing having oppositely facing windows therein and a display element within the housing having related markings thereon, the individual ones of the said related markings being simultaneously visible through a respective one of the windows and the windows being provided in such disposition on the housing that the respective markings visible thereat can be viewed only from opposite sides of the housing.

Abstract: An educational toy comprises a base provided with a plurality of passages having a V-shaped cross-section, a lid having a plurality of openings corresponding to each said passage, and a series of replaceable question and answer combination cards having one opening at each question and answer illustration section. The quiz results are indicated by the rolling of at least one bead.

Abstract: A plurality of signals are generated to represent different simulated picture elements, such as markers, road lines, obstacles, etc., which might be encountered along the pathway of a vehicle such as an automobile or an aircraft. These signals are separated into groups representing height, longitudinal and lateral dimensions in three-dimensional space and corresponding intensity levels for each of various picture elements to be displayed, and the signals in each group are multiplexed together to form a composite signal for each of these signal components. The height, longitudinal and lateral groups of multiplexed signals are transformed to perspective form in accordance with a "perspective" transformation. Curvature may be given to the simulated pathway by transforming the composite perspective lateral signal in response to a curve signal generator. The composite horizontal signal modified in accordance with vehicle heading is fed to the horizontal control circuits of the display device.

Abstract: Apparatus to artificially simulate arteries of a limb for training medical personnel to puncture arteries and veins. The device comprises a hollow arm shaped member constructed of a resilient material having two grooves formed on the exterior thereof in the area of the elbow and wrist simulating the brachial artery and radial artery area. A resilient artery is formed of tubing which is positioned through the hollow bore of the arm and through the grooves in the elbow and wrist area. A latex skin is positioned over the arm to cover the tubing and grooves to simulate the skin. The tubing is attached to a liquid container above the arm to simulate blood and cause a arterial or venous pressure for a lifelike back flow of liquid into the syringe.

Abstract: A shoe construction including a pre-formed unitary sole member made from a flexible, resilient material and including a concave top face pre-shaped to fit the bottom of the wearer's foot. The outer marginal portion of the bottom face of the sole member is recessed to form a stitching land for securing the sole member directly to the forepart lower marginal portion of the shoe upper. A soft, resilient sole filler member may be secured to the top face of the sole member, with the rear portion of the sole filler member being secured to the front portion of the shank tuck.

Abstract: A pliable inner boot for insertion within a rigid outer shell of a ski boot is formed of resinous foam material. The inner boot is bifurcated at the front, and is provided with recesses in the vicinity of the shin region and preferably at the heel pocket. These rcesses soften the feel of the inner boot at the shin and ankle regions when it is compressed by closure of the rigid outer shell.A pliable custom fitting reservoir (fit pack) is interposed between the rigid outer shell and the inner surface of the inner boot in the vicinity of the heel pocket and the instep portions of the inner boot. This reservoir may be either integral with or separate from the inner boot. It may include a conduit adapted to receive a liquid resin reaction mixture from a source remote from the ski boot. Alternatively, the fit pack may contain isolated components of a reaction mixture which are mixed by kneading just prior to use.

Abstract: An earthmoving implement (10) has a sidewall member (12) and a cutting edge (14), and an adapter (26) is releasably secured thereto. The sidewall member (12) has a step (20), and the adapter (26) has a pair of outer and inner mounting portions (35, 36) defining a first slot (38) therebetween. The adapter (26) also has a bottom portion (40) connected to the outer mounting portion (35) and defining a second slot (42) with the inner mounting portion (36) so that the first slot (38) straddles the sidewall member (12) and the second slot (42) straddles the cutting edge (14). A projection (80) is defined on the adapter (26) forwardly of the first slot (38) for transmitting a portion of a working force on the adapter into the step (20), and a fastening device (28) releasably connects the adapter (26) to the implement (10) and transmits another portion of the working force into the sidewall member (12).

Abstract: A device is provided for attaching a hollow tooth to the nose of a fixed support, for example a support forming part of the bucket of a mechanical shovel. The nose has a curved bore and a resilient steel cotter passes through the bore and through orifices in the walls of the tooth. One end of the cotter cooperates with an inclined plane of one orifice and the other end having a shoulder cooperates with a projecting portion of a wall of the other orifice.

Abstract: A rotary index device which is particularly adapted to be mounted on the dashboard of a motor vehicle. The device includes a cylindrical inner member which is rotatingly mounted within an outer cylindrical casing. The inner member has one of a plurality of different information-bearing code sheets secured to the peripheral surface thereof, and the outer casing has a through aperture extending longitudinally along the entire length thereof through which at least one line of the information may be viewed. A magnifying lens is selectively positionable over the through aperture for magnifying the information and facilitating viewing thereof by, for example, the driver of the vehicle. The outer casing may be angularly adjustable with respect to the viewer by a pivotal connection to a mounting bracket which preferably includes an adhesive on the undersurface for securing same to the dashboard of the vehicle.

Abstract: A greeting card having a front leaf, a center leaf and a rear leaf is formed of a single piece of paper folded into quarters and cut at the upper edge of the center leaf, enabling the center leaf to move from a position where it overlies the rear leaf to a position where it overlies the front leaf. Pictorial material on the center leaf has the same shape and location as pictorial material on the underlying leaves; and, the center leaf has transparent cutouts which expose textual or pictorial material on the underlying leaves.

Abstract: The display frame includes at least two different display areas within the same frame for exhibiting in one area a two-dimensional object and in another area a three-dimensional object. A special display tray is used to cradle the three-dimensional object so that the object can be exhibited through the display frame.

Abstract: A license plate lock box assembly which is adapted to be secured about, preferably, the rear license plate of a motor vehicle. The assembly comprises a holding means adapted to be secured to the motor vehicle, a transparent cover plate adapted to cover and enclose the license plate, and a locking means adapted to releasably lock the cover plate to the holding means. The cover plate includes a horizontal slot through which notices of traffic violations may be inserted and retained in the assembly.

Abstract: A sign assembly for motorist comprises an accordion folded sign element with each fold having a given message and which may be folded to expose the desired message with the sign element being mounted within a similar foldable holder so that the sign assembly is foldable as a unit from an inoperative or folded condition to an operative or extended condition and vice versa.

Abstract: An over-under firearm having a breech block, a barrel block, at least one shot barrel mounted in the barrel block and a rifle barrel superimposed on the shot barrel at a small angle relative thereto, and a hinge mounting the barrel block to the breech block to afford pivoting about a vertical axis for loading and unloading.

Abstract: An over-under firearm having at least one shot barrel and a rifle barrel superimposed relative to one another and mounted in a barrel block designed to pivot relative to a breech frame so that the rear ends of the barrels are disposed laterally for loading. The breech frame surrounds the top, bottom and one side of the barrel block, and arcuate ribs and grooves are provided between the top and bottom of the barrel block and the breech frame. A breaking mechanism is provided to displace the barrel block laterally after the barrel block has been unlocked from its operating position in the breech frame. A mechanism is provided for withdrawing the firing pin and cocking the hammers in response to further movement of the barrel block relative to the breech frame.