Abstract: An improved retention mechanism for a bicycle helmet is provided. A helmet including a retention mechanism comprises a shell for protecting a head of a person and a fit system elastically coupled to the shell. The fit system comprises a bowl designed to fit an occipital region of the person's head and a hinge for coupling the fit system to the shell, the hinge permitting the fit system to move. The fit system further including a spring element for positioning the bowl against the occipital region of the person's head, to stabilize the helmet against the person's head.

Abstract: A sanitary washing device cleans a nozzle pipe thereof automatically. The sanitary washing device includes a changeover valve supplying a warm water to a nozzle pipe, a nozzle pipe selectively accommodated in a cylinder, and an ejecting outlet provided on the end portion of the nozzle pipe to spray warm water in order to wash a portion of the user sitting on a toilet bowl. The nozzle pipe is retracted in order to be accommodated in the cylinder again when the warm water supply through the changeover valve is stopped. A nozzle pipe washer is positioned to spray washing water onto the nozzle pipe. By controlling the changeover valve, a nozzle pipe washer ejecting outlet sprays the warm water onto the nozzle pipe in accordance with the movement of the nozzle pipe.

Abstract: A process for dry cleaning fabrics comprising the steps of: (i) placing one or more fabrics to be cleaned in a device which provides heat and agitation; (ii) placing one or more carrier sheets in the device wherein the carrier sheets have about 200 grams of a liquid cleaning/refreshment composition releasably absorbed therein; (iii) heating the air within the device to at least about 130° F. (55° C.); and (iv) agitating the fabrics and the carrier sheets until at least about 40% by weight of the liquid cleaning/refreshment composition from the carrier sheets has been evaporated and vented from the device. There is further provided a kit for dry cleaning fabrics comprising: one or more carrier sheets; and from about 200 grams to about 1,000 grams of a liquid cleaning/refreshment composition, wherein the one or more carrier sheets can absorb at least about 200 grams of the liquid cleaning/refreshment composition.

Abstract: A brush core and the method for making a brush core for use in substrate scrubbing are provided. The substrate can be any substrate that may need to undergo a scrubbing operation to complete a cleaning operation, etching operation, or other preparation. For instance, the substrate can be a semiconductor wafer, a disk, or any other type of work piece that will benefit from a brush core that can deliver uniform controlled amounts of fluid through the brush along an entire length of the brush core. The brush core is defined by a tubular core having a length that extends between a first end and a second end. The first end has an opening into a bore that is defined through a middle of the tubular core and extends along an inner length of the tubular core. A first plurality of holes are oriented along a plurality of first lines that extend in the direction of the length of the tubular core, and each of the first plurality of holes define paths to the bore of the tubular core.

Abstract: A vacuum cleaner installation has a unit with an outer housing installed within the thickness of an outside wall of a room. The housing contains a blower, a bag for waste material and a hose. The blower is connected to draw waste material along the hose and into the bag, the exhaust air venting externally of the room through a grille on the outside wall.

Abstract: A portable surface cleaning apparatus including a base module for movement along a surface, an upright handle pivotally attached to the base module, a liquid dispensing system including a fluid supply chamber in the form of a bladder for holding a supply of cleaning fluid, a fluid recovery system including a tank on the base module having a fluid recovery chamber for holding recovered fluid and housing the flexible bladder, wherein the recovery chamber is in fluid communication with the fluid supply chamber and the pressure in the flexible bladder is equalized with the pressure in the tank as the cleaning fluid is dispensed from the supply chamber and the dirty liquid is collected in the recovery chamber. The base module includes upper and lower housing portions and the upright handle is pivotably mounted to the base module through at least one bearing for rotatable reception in the housing.

Abstract: A door hinge for vehicles, incorporating:

Abstract: A composite hook and loop fastener in the form of an elongated strip has an elongated loop component, a hook component permanently affixed to the loop component, and a backing layer disposed on a face of the wrap tie in a discrete region. The backing layer is used for permanent attachment of the wrap tie to a supporting surface. One end of the loop component is available for encircling an object to be wrapped and engaging the fastener elements of the hook component. The loop component has a self-supporting web of entangled fibers, the fibers forming both a sheet-form body and hook-engageable, free-standing loops extending from at least one surface of the body, and the hook component has fastener elements extending from a common base. The backing layer may be a pressure sensitive adhesive or a synthetic resin.

Abstract: A belt lock includes a casing, the casing having a serrated engagement portion and a bearing portion respectively disposed at a bottom wall thereof at a top side, and two parallel upright side walls at two sides of the bottom wall, and a locking unit pivoted to the upright side walls of the casing and adapted to lock a belt being inserted through the casing, the locking unit including a handle pivoted to the casing and turned between a locking position and an unlocking position, and a sector-like swivel pressure block pivoted to the handle, the handle having two barrels bilaterally disposed at a front side thereof and respectively pivoted to the pivot holes of the upright side walls of the casing, the swivel pressure block having a serrated engagement portion adapted for pressing on the inserted belt against the bearing portion of the casing when the handle is turned to said locking position.

Abstract: A towel clip having a hollow elongated body with an opening running the length of the body wherein the body is made of a flexible memory material, preferably rubber or a plastic and most preferably polypropylene. The body is preferably circular and the opening preferably covers about 75° to about 105° of the diameter to slip over a towel draped over the bar of a chair.

Abstract: An electronically controlled sample warper having a yarn exchanging mechanism is provided which comprises a rotary creel supporting a plurality of bobbins around which different kinds and/or the same kind of yarns are wound and a bobbin station supporting a plurality of bobbins on which different kinds and/or the same kind of yarns are wound in a standby state. With this construction, it is possible to employ various kinds of yarns and perform yarn exchanging thereof unlimitedly, thus enabling various pattern warping to be freely performed with the reduced warping time.

Abstract: A feed head has a delivery path along which nuts are fed to a pressing station in the feed head, the pressing station having a pressing die which is reciprocated transversely to the delivery path under the action of a press to fasten a nut to a sheet metal member. A cam is provided to reciprocate the pressing die manually to facilitate clearance of blockages in the feed head, and also to hold the pressing die in its lowered position to allow operation of the press without operating the die. A sensor for detecting nuts at the pressing station is positioned on the end of the delivery path, enabling a narrower feed head design. A electrical coupling and nut delivery tube are integrated to facilitate connection in confined spaces.

Abstract: A drill-chuck jaw is made by first forming an elongated metal body with a toothed back face and a front face, then machining a longitudinally extending groove having sides and a floor in the front face, and forming inwardly projecting and longitudinally spaced retaining bumps on the groove sides. A hard-metal insert is fitted into the groove between the retaining bumps and then bonded to the body in the groove. the body is heat-treated, that is annealed, before machining the groove in it to reduce internal stresses. Then the body is cleaned and oiled to prepare it for machining and to eliminate any oxidation created by the heat treatment. After machining the body and before fitting the insert the body is deburred and cleaned again. Normally the insert is bonded to the body by soldering or brazing. In order to allow the insert to seat directly on the jaw and not be held off it by the solder a channel is formed between the insert and the body in the groove.

Abstract: A wiper blade includes a lever assembly that has several types of levers. The levers of each type are efficiently manufactured in the following manner. First, a lever unit, which has a frame bar and several levers integrated with the frame bar, is pressed. Each lever has a hole. Then, a wire is fed through the holes of the levers. The frame bar is separated from the levers to form a hanging unit, which includes the wire and the levers hanging from the wire. In this state, the lever is coated with paint. After the paint is dried, the wire is removed form the levers.

Abstract: The invention relates to an inductor comprising a plurality of interconnected conductive segments interwoven with a substrate. The inductance of the inductor is increased through the use of coatings and films of ferromagnetic materials such as magnetic metals, alloys, and oxides. The inductor is compatible with integrated circuit manufacturing techniques and eliminates the need in many systems and circuits for large off chip inductors. A sense and measurement coil, which is fabricated on the same substrate as the inductor, provides the capability to measure the magnetic field or flux produced by the inductor. This on chip measurement capability supplies information that permits circuit engineers to design and fabricate on chip inductors to very tight tolerances.

Abstract: In an exemplary embodiment, the apparatus includes a first station (32), a second station (34), and a third station (36). At the first station (32), raw magnetic material strip (24) is de-reeled from a stock reel (40) and a predetermined amount of the raw magnetic material strip (24) is fed and measured as the magnetic material strip (24) is transported to a winding mechanism (60). In the winding mechanism (60), the magnetic material strip (24) is continuously wound in and through an opening (22) formed in a bobbin (12) to form a wound transformer core. Preferably, a pair of bobbins (12,14) are used and the magnetic material strip (24) is continuously wound through openings (22) formed in each of the bobbins (12,14). After winding the predetermined amount of magnetic material strip (24) through the bobbins (12,14), the magnetic material strip (24) is cut at a predetermined measured location to produce a trailing edge (26) of material (24).

Abstract: A chip-type electronic device has a substrate with a vertically extending groove formed on each of its mutually opposite edges. A solder material fills these grooves partially to a height which is below the top surface of the substrate. Electrode patterns are formed on these edges of the substrate including the inner surfaces of these grooves. A semiconductor electronic element is attached onto the top surface of the substrate. A resin mold seals the entire top surface of the substrate inclusive of the semiconductor element, extending to positions of the edges of the substrate and protruding partially into the grooves so as to serve as hooks to securely attach to the substrate.

Abstract: A system for delivering fuel comprising a receiver coupled in liquid communication with a fuel tank of a vehicle, a nozzle coupled in liquid communication with a fuel source and interactive alignment structure for mating the nozzle with receiver in response to movement of the receiver and the nozzle.

Abstract: A method of manufacturing a gas turbine engine fan blade (10) comprises forming three metal workpieces (30, 32, 34). The metal workpieces (30, 32, 34) are assembled into a stack (36) so that the flat surfaces (38, 42, 46, 48) are in mating abutment. Heat and pressure is applied across the thickness of the metal workpieces (30, 32, 34) to diffusion bond the metal workpieces (30, 32, 34) together to form an integral structure (80). The integral structure (80) is upset forged at one end (58) to produce an increase in thickness (82) for forming the blade root (26). The upset forged integral structure (80) is then hot creep formed and superplastically formed to produce the required aerofoil shape and the thickened end (82) is machined to form the blade root (26). The method enables thinner metallic workpieces with better microstructure to be used and increases the yield of metallic workpieces.

Abstract: A nozzle for a liquid injection device, wherein a ceramic green sheet (11) used as a bottom part of a liquid injection device having a nozzle (12) disposed between a die (2) and a stripper (3) storing a punch (4) and the punch (4) is moved to form a hole part constituting the nozzle (12), the green sheet (11) is disposed between a die (2′) having a cavity wherein the outer shape of a projected part (12a) of the nozzle (12) is reversed and a stripper (3′) storing a punch (5) so that it is positioned in the direction opposite to that in the previous disposition and the punch (5) is moved to obtain the outer shape of the nozzle (12), and the green sheet (11) is baked, whereby, even in a drying device to which air is constantly applied vertically to the delivery direction of liquid, no injected liquid is deposited substantially at the tip part of the nozzle (12).

Abstract: A magnetic shaving system includes a pre-trimming solution containing particles having magnetic properties and a shaving apparatus having a magnet. The shaving apparatus may include only a magnet or may include a magnet in proximity of a typical razor blade. The pre-trimming solution is applied to the desired area and the magnetic shaving apparatus is applied over the solution. The magnetic solution surround the hairs and causes the hairs to be drawn toward the magnetic shaving apparatus and away from the skin, yielding a more comfortable and effective shave.

Abstract: The invention relates to a shaving apparatus comprising a first blade (1) and a second blade (3) having parallel cutting edges (5, 7) extending perpendicularly to a cutting direction X of the blades. The second blade follows the first blade, viewed in the cutting direction. According to the invention, the first blade comprises a blocking element (15) which is provided on a side surface (17) of the first blade at a distance (d) from the cutting edge (5) of the first blade, which distance (d) is much smaller than an average diameter of a hair (25) to be shaved by means of the apparatus, the first blade being periodically displaceable in the cutting direction by a displacing unit (11) of the apparatus from a first position, in which the cutting edge of the first blade is close to the cutting edge of the second blade, to a second position.

Abstract: A viewing window for covering an aperture in a hand-held circular saw includes an optically transmissive member adapted to be coupled with the guard. The member is movable between a closed position, wherein the member substantially covers the aperture, and the open position, wherein the member at least partially uncovers the aperture, to allow the cleaning of the member. A structure is provided for biasing the member to the closed position.

Abstract: The invention relates to scissors. Hitherto scissors have been formed with rigid and identical handles to allow use in either hand, but with some discomfort to the user, or with handles specifically shaped to suit a right-handed or a left-handed user, but not both. The object of the invention is to provide a pair of scissors able to be used in comfort by both right-handed and left-handed users, an objective met by a construction comprising blades and associated handles pivotally secured together, the handles forming respective finger and thumb bows that are symmetrical about the center plane at the mid-point through their thickness, at least one (thumb) bow being formed as a rigid structure from the forward end towards the pivot to a point along the length of that bow, from where the at least one (thumb) bow has a rearward part formed from a form-stable but resilient and/or flexible material.

Abstract: The invention relates to a device for cutting material such as metal rod. The device comprises a diaphragm type air brake chamber having a wedge mounted to an output shaft of the chamber, a cutting assembly mounted to the air brake chamber, the assembly comprising two pivotally mounted cutting members with opposed blades with the members biased to maintain an opening between the blades, and a handle for gripping the device rearwardly of the cutting assembly. The device is configured so that on actuation of the air brake chamber, the wedge is driven between ends of the cutting members distal the blades to cause the blades to pivot towards each other.

Abstract: An opener having a grip-like body in which at one end is integrated a cutting mechanism for cutting open tins. An oppositely-lying thickened end has a receiving groove in which a pull hook is pivotally mounted about a pivot pin over a predetermined angle. For opening tear-open lids, a pull-ring is captured within an attachment recess on a pull hook inner edge. When pivoting the grip-like body the pull hook rolls along a rolling back of the pull hook, on the can lid and pulls up.

Abstract: An apparatus and method for positioning packaged semiconductor devices having different rectangular shapes and sizes. A positioning apparatus includes an adjustable alignment guide releasably coupled to a base. The adjustable alignment guide may be positioned along a first axis to partially define a recess into which the packaged semiconductor devices are placed during positioning. The positioning apparatus may also include additional adjustable alignment guides that may be positioned along the first or a second axis to further define the recess into which the packaged semiconductor device is to placed during positioning. The adjustable alignment guides may have alignment surfaces against which the integrated circuit rests when placed into the recess that is partially defined by the alignment surfaces.

Abstract: A device for generating angles has a ruler-shaped basic rail having a first guide extending in a longitudinal direction of the basic rail. A stop rail is arranged in the first guide of the basic rail and is rotatable and slidable into different positions relative to the basic rail and securable in the different positions. The stop rail has an underside provided with depressions positioned at an acute angle to one another and forming a star-shaped arrangement. The basic rail has a projection that engages the depressions.

Abstract: A coordinate measuring machine including a support platform for supporting an object. Scanning means is supported by the support platform. The scanning means includes a probe assembly and a non-contact scanner. Drive means is connected to at least one of the probe assembly and the non-contact scanner for moving the probe assembly and non-contact scanner relative to each other. The probe assembly includes a probe movably disposed in a guide tube. The probe includes a shaft and a tip integrally formed from either a fiber-optic or non-fiber-optic material. The tip extends from the guide tube so as to be detectable by the non-contact scanner. The tip may include one or more stylus. During operation the tip contacts the object and the non-contact scanner detects the tip to determine the corresponding coordinates of the object. A light source illuminates the tip for improved detection of the tip. When the probe is formed of a fiber-optic material, light is emitted through the probe.

Abstract: A calibrating body consists at least in part of a carbon fiber composite body. The composite body is formed from a porous material from a carbon-containing matrix, into which carbon fibers are embedded, this matrix is thickened by fluid infiltration of Si, which is essentially converted by reaction with carbon to SiC. The overall portion of Si and SiC is a maximum of 60% by volume. The carbon fibers have a minimum length of 3 mm.

Abstract: A measuring device comprising a planar elongate member having a first or upper face and a second or lower face; the first face bearing a plurality of indicia markings thereon denoting longitudinal distances between the markings; and the second face having a layer of a self-adhesive composition. The adhesive coated measuring tape is user-friendly in providing a simple, fast and accurate method of maintaining a precise position on an object.

Abstract: A dial gauge (1A) has stem bush (20) having a fitting (21) fitted to an inner wall of a stem (5) and having a predetermined clearance between a spindle (3), a holder (22) for slidably holding the spindle (3) while securing a predetermined clearance against the inner wall of the stem (5), and an elastically deformable connector (23) for connecting the fitting (21) and the holder (22), whereby an influence of deformation of the stem (5) and the fitting (21) on the holder (22) during clamping can be minimized, so that the dial gauge (1A) can be fixed to a supporting stand without deteriorating slidability of the spindle (3).

Abstract: Apparatus (10) to transport and cool rolled products (11) such as bars, round pieces, rods or similar, able to be arranged downstream of a coil-forming head (12), comprising a plurality of transport rollers (20), at least partly motorized and arranged parallel to each other so as to define a substantially horizontal transport plane on which said rolled products (11) arranged in coils (16) are able to lie, ventilation means (22) arranged in correspondence with said transport rollers (20) to blow air towards said rolled products (11) and conveyor means to convey towards the lateral edges of said coils (16) a greater quantity of air than that conveyed towards the central zone of said coils (16), said conveyor means comprising a plurality of elements (23), arranged at intervals between said transport rollers (20), each of said elements (23) being shaped so as to define transit channels (27) having at least a first transverse section which is greater in correspondence with the ends of said transport rollers (20) a

Abstract: A moisture and temperature regulating insole for a shoe. The shoe includes a body having a cover and a base layer connected to the cover, and a sole having a base connected to the body and an expansive foam between the body and the base. The insole includes an absorbent layer, an elastic layer, and a closure layer. The insole is connected to the body and to the sole such that the insole absorbs the moist air within the shoe during an advance phase of the foot when the shoe is detached from the ground or floor and delivers the absorbed air with a lower content of moisture and temperature during the support phase of the foot when the shoe is supported on the ground or floor, in part to the environment and in part to the shoe body.

Abstract: A metatarsal protector for footwear consists of a body molded from resilient plastics material, thus facilitating walking and kneeling, the material being sufficiently flexible that it can be molded flat and bent to the required saddle shape when it is incorporated into the footwear close against the upper inner surface. The range of hardness required for the material is comparatively narrow, so that it is sufficiently flexible, but can still meet certification requirements, and as measured by a Durometer A test is between 35 and 50 Shore. The protector comprises a plurality of integral ridged projections protruding from one surface, forming between themselves a corresponding plurality of open-mouthed recesses, each of which is surrounded by a single projection (e.g. giving a circular recess) or by a plurality thereof intersecting one another (e.g. giving rectangular or triangular recesses). When an impact force is applied to the metatarsal region the resilient material deforms and absorbs the force.

Abstract: A shell, particularly for a ski boot, constituted by a box-like main body which is open in an upward region and is rigidly coupled to a sole. The shell has, at the foot instep region, two arc-like partially overlapping plates, each of which is rotatably pivoted to the shell by pivots arranged laterally to the shell on an axis which is approximately parallel to the resting plane of the sole. The rotation of the two plates is limited by a pivot and slot connection arranged in the region in front of the heel.

Abstract: An article of footwear includes a torsion system constructed of a material and configured to allow, in a pre-selected manner, rotation of a forefoot portion of the article of footwear relative to a rearfoot portion of the article of footwear about a longitudinal axis of the article while substantially precluding bending in an intermediate portion thereof.

Abstract: A snow thrower comprised of a snow chute and chute deflector includes a joystick controller that may be adjusted between first, second, third and fourth positions. Adjustment of the joystick into one of the four positions causes rotation of the chute in clockwise and counterclockwise direction or causes the deflector to pivot upward or downward respectively. Both, the chute and the deflector are actuated by electric motors.

Abstract: A mounting system for mounting a sign, such as a sheet or a panel to a generally horizontal shelf includes a display portion including an arm forming a portion of and defining a sign receiving region. The display portion includes a display hinge portion defining an axis of rotation. The display portion further includes a detent spaced from the axis of rotation, defining a radially distal-most portion. A shelf mounting bracket mounts the display portion to the shelf. The shelf mounting bracket includes a pivoting element cooperating with the display hinge portion for pivotally mounting the display portion to the shelf mounting bracket. The display portion is pivotal between a first position and a second position. The shelf mounting bracket includes a flexible tongue configured to engage the detent to maintain the display portion in the first or second position and to disengage from the detent to move the display portion to the other of the first or second position.

Abstract: A mounting apparatus is disclosed for attaching a sighting device onto a weapon. The mounting apparatus has a rail disposed on part of the weapon in a longitudinal direction. The rail has a pair of longitudinally extending opposed sides and a longitudinally extending first attachment element on each of the opposed sides. A removable mounting base has a pair of longitudinally extending side edges and a longitudinally extending second attachment element on each side edge. Each second attachment element is complimentary to a corresponding one of the first attachment elements. The mounting base is slidingly and longitudinally engaged with the rail via the complimentary first and second attachment elements. The mounting base is formed of at least two parts which are slidable against one another in a transverse direction. A spring mechanism produces a spring force and is arranged to bias the two parts of the mounting base into engagement with the rail.

Abstract: A fishing lure retriever having a teardrop-shaped weight of lead or similarly dense material. Clipping means are attached to the weight. The weight and clipping means are coated in a thin layer of vinyl or similar resilient material. Where a fishing lure has become entangled underwater, the retriever is attached to the fishing line and permitted to descend by gravity along the line to the point of entanglement. Motion of the fishing line with the retriever in place near the entangled lure results in controlled movement of the weight near the entangled lure effecting disengagement of the lure.

Abstract: A novel crosslinked emulsifier is employed to produce a stable aqueous hydrocarbon fuel emulsion.

Abstract: The present invention relates to horticultural products and a method for making gardening products which have a dye or fragrance added to the products.

Abstract: A biodegradable tray for raising seedlings is obtained by obtaining a pulp mold from pulp slurry by suction molding and hot pressing after the molding. Thus, there is provided a biodegradable tray for raising seedlings composed of a pulp mold that has superior mechanical strength and dimensional accuracy during use and can easily be degraded after raising seedlings.

Abstract: A power drive system is adapted for a sliding door mounted on at least one side of a vehicle for sliding movement forwardly and rearwardly of the vehicle. The system includes a reversible motor. A bracket is guided within a guide along a fixed path between the opened and closed positions of the door. An elongated drive member is slidably disposed within the guide and connected to the bracket at one end for driving the bracket along the fixed path. A translator mechanism operably engages with the drive member for powering movement of the door. The translator mechanism can include a rotatable hub, operably engageable with the drive member, a gear transmission for driving the hub, and a clutch mechanism for connecting the motor to the transmission. The translator mechanism preferably has sufficient power to pull the sliding door into a primary latch position with respect to the corresponding portions of a latch mechanism attached to the door and frame defining the door opening.

Abstract: An plug-in module for adjusting motors of electric-motor operated window openers to be used in a motor vehicle, the plug-in module has at least one plug insertable in a transmission housing of a window lifter along a mounting direction, a plug housing composed of a synthetic plastic material with partially injection molded contact elements and motor contacts, the motor contacts having freely located connection portions which have an end-side contact portion for contacting with an associated countercontact and also a spring portion which supports the contact portion and allows a position orientation of the contact portion to the countercontact.

Abstract: A door assemble for vehicles includes a space defined between a door inner panel and a door trimming, in which a door locking device for holding a vehicle door on a vehicle body is accommodated so as to be secured on the door inner panel.

Abstract: The present invention is an enclosed rain gutter for draining water from the surface of a sloped roof and conducting it to a down spout. The invention rain gutter includes a channel that is covered by collecting surface. The collecting surface has openings that divert water into the channel by using the surface tension property of water that causes water to adhere to a surface. While the collecting surface openings divert water into the channel, they also exclude debris from entering the channel and in particular they exclude debris that would be large enough to obstruct a down spout.

Abstract: A mounting assembly is provided for puncture-free attachment of a snow guard system to a roof seam. The assembly comprises a mounting block, at least one clamping member, and an actuation member. Once actuated, the clamping member prevents relative movement between the mounting block and the seam. At least one clamping member positioned adjacent a groove located in the base of the mounting block. The clamping member includes a first side having at least one primary contact surface outwardly protruding a first distance from the first side. The clamping member also includes at least one secondary contact surface protruding a second distance from the first side. In the preferred embodiment, the second distance is less than the first distance thereby making the primary contact surface(s) the first to engage the seam upon actuation of the member. Preferably, the clamping member includes a second side having at least one protrusion for engagement with a first end of the actuation member.

Abstract: A concrete step assembly includes risers with each having a longitudinal projection on its upper end for disposition in a longitudinal receptacle in a bottom surface of a tread resting on the riser. Each riser has a pair of slots in its bottom surface to receive a portion of a projection on a concrete block of each of two supports formed of concrete blocks. Each tread has a pair of transverse receptacles in its bottom surface to receive a portion of a projection on a concrete block of each of the two supports. The transverse receptacles communicate with the longitudinal receptacle in the bottom surface of the tread to enable the portions of the projections on the concrete blocks therein to abut the longitudinal projection on the riser in the longitudinal receptacle. When the concrete block has another of the concrete blocks thereabove, the projection on the lower of the two concrete blocks fits in a groove in the bottom surface of the upper concrete block.