Abstract: In a method for making a self-propelled impact boring tool, the tool body is formed by swaging a steel tube to form the tapered nose of the tool. This results in less wasted steel as compared to conventional machining of a solid steel bar to form the body, which is the largest single part of the tool. The tool body may then be fitted with a tool anvil of slightly different dimensions than the forming anvil used during swaging to provide an interference fit.

Abstract: A knob and skirt assembly having a dial which can be calibrated relative to a control shaft and easily assembled in the proper position of alignment. The assembly includes a knob having a handle portion and hub portion. The knob portion has a control shaft receiving socket at the outer end thereof. The handle portion has an axially facing annular rim. At least one arcuate segment of teeth is formed on the annular rim. A disk shaped skirt has a central opening which fits over and receives the hub of the knob. A shallow well is formed in the skirt surrounding the central opening. Teeth formed in at least one arcuate segment are positioned in the well to mesh with the teeth on the annular rim. Ribs on the knob are heated and bent over against the skirt to fasten the knob to the skirt and to frictionally resist rotation of the hub and the skirt relative to each other until a predetermined rotational force is applied. An indexing notch is formed in the central opening of the skirt at the peripheral edge thereof.

Abstract: A pair of truss brackets are secured to the roof of an underground passage adjacent to opposing ribs of the passage. The truss brackets each include a roof engaging surface and a truss supporting arm member extending from the roof engaging surface. A pair of U-bolts are supported by the arm members of the truss brackets. Each arm member extends horizontally from the truss bracket to an enlarged end portion of the arm member. The U-bolt is horizontally movable in a vertically hanging position on the arm member and is restrained by the enlarged end portion from disengagement from the arm member. The U-bolts are pivoted on the truss brackets to a horizontal position for connection to truss members which are connected to each other and tensioned to apply an uplifting force to the roof. As the truss members are connected and tensioned, the U-bolts are retained for a range of horizontal movement on the arm members to facilitate adjustments in the position of the U-bolts on the truss brackets.

Abstract: In a method for making a self-propelled impact boring tool, the tool body is formed by swaging a steel tube to form the tapered nose of the tool. This results in less wasted steel as compared to conventional machining of a solid steel bar to form the body, which is the largest single part of the tool. The tool body may then be fitted with a tool anvil of slightly different dimensions than the forming anvil used during swaging to provide an interference fit.

Abstract: A method of manufacturing a wiper blade for a windshield wiper system of a motor vehicle is described, in which wiper blade a pivot pin, that is cylindrical all along its length, is non-rotatably fixed onto a secondary yoke and engages into bearing bushes by way of its ends, which bearing bushes are non-rotatably fixed into the side walls of a primary yoke. This articulated connection is advantageous with respect to corrosional behaviour and thus with respect to the lifetime in comparison to known articulated connections with an articulated rivet that is non-rotatably connected with the primary yoke.

Abstract: A method is for selectively locking two frame members of a window or door to prevent sliding movement of one frame relative to the other. The method involves providing an aperture in one frame, securing a sleeve to the other frame in alignment with the aperture, inserting a bolt through the sleeve and into the aperture. The bolt includes two lengths which are pivotably connected together. When the bolt is in retracted position, one portion of the bolt can be pivoted relative to the other portion of the bolt and then moved along a line perpendicular to the axis of the first portion of the bolt.

Abstract: A self-captivating screw becomes captive in a metal sheet, yet is freely rotatable after a simple pressing of the two parts. The screw is applied to the sheet by pressing against an anvil having a circular cavity in alignment with the panel aperture. The screw has an elongate shank with a head at one end and a threaded portion at the opposite end. The head and threaded portion are greater in diameter than the shank. The screw includes a displacer collar just beneath the head which, under pressure, deforms the metal sheet causing the cold flow of panel metal inward about the screw shank without gripping it tightly. The anvil cavity has a diameter greater than the major diameter of the screw threads, but less than the diameter of either the displacer collar or the minor diameter of the threads.

Abstract: A modular brake system having a housing and cables connecting a foot or hand brake lever and wheel brakes. The first cable passes through the housing and a reactive slide member therein which simultaneously imports tension to two or more cables to actuate the braking mechanism of one or more wheels.

Abstract: A fastening device for attaching a temple to an eyewire of an eyeglass frame, a method of fastening using the fastening device and apparatus for impelling an elongated pin forming part of the fastening device. The fastening device is so constructed and arranged to insert an elongated pin through aligned hinge barrels of a hinge to be connected with its pointed end received unit a backing member. A gun-like member is used for inserting an elongated pin having a head at one end and a pointed tip portion at its other end and a circumferential groove adjacent the pointed tip portion. The elongated pin is so constructed and arranged the backing member that receives the pointed tip portion and the circumferential groove of the elongated pin therewithin when the enlarged head of the elongated pin is fully inserted through aligned hinge barrels and into the backing member.

Abstract: An arm connectible to a seat back and having teeth formed at one end is pivotally mounted to a seat bottom frame formed of first and second spaced, fixedly connected plates. A toothed drive gear mounted between the first and second plates and rotated by a drive unit meshingly engages the teeth on the arm to rotate the arm between infinitely adjustable positions. Aligned slots are formed in the first and second plates and receive opposed tenons of a rivet having the arm rotatably mounted about a central body portion.

Abstract: A finger stick device for making a skin incision includes a blade pivot arm having a first end pivotally coupled to a housing and a second end having an upper sloped surface and a lower surface. A blade is affixed to the second end such that its cutting edge extends away from the lower surface. A resilient bias member when actuated traverses the upper surface and depresses the second end of the blade pivot arm, such that the blade exits the housing and incises the skin. The incising operation is complete upon the bias member traversing the sloped upper surface of the blade pivot arm. Also disclosed herein is a method for manufacturing the finger stick device, in which the bias member and blade pivot arm are molded as a monolithic unit. A blade is attached to the blade pivot arm, and the blade and monolithic unit are inserted into the housing. Further disclosed is an embodiment in which the housing is formed of two uniformly shaped halves, which when joined, provide an internal space for the monolithic unit.

Abstract: The present invention relates to a method for assembling a modular brake system on a vehicle by the steps of preparing a reactive slide member having pins to facilitate reciprocal movement and a bore therein for receiving a cable strand; operatively associating a first cable conduit having a first cable strand disposed therein with the reactive slide member such that the first cable strand can slidably move through the conduit and reactive slide member; preparing a housing having inner walls which define a cavity, an opening for receiving the slide member, openings for allowing cable strands to enter or exit the cavity and channels on the inner walls for receiving the pins of the reactive slide member; affixing a second cable conduit to one of the openings of the housing for receiving a cable strand which exits the housing cavity through that opening; preparing a third cable conduit having a third cable strand slidably disposed therein; placing the reactive slide member into the housing through its respective

Abstract: In a method for making a self-propelled impact boring tool, the tool body is formed by swaging a steel tube to form the tapered nose of the tool. This results in less wasted steel as compared to conventional machining of a solid steel bar to form the body, which is the largest single part of the tool. The tool body may then be fitted with a tool anvil of slightly different dimensions than the forming anvil used during swaging to provide an interference fit.

Abstract: A mechanical lock where a rod axially translatable through a lock housing is normally gripped by a clutch spring axially fixed to the housing, and a lever is actuated for unwinding the spring to release the rod. The lock housing is formed in a single piece by die cutting and stamping from flat sheet stock in a sequence which can be carried out in a single progressive die, to minimize the parts count and simplify assembly of the lock.

Abstract: An inside door handle assembly is comprised of a bezel secured to a door of a vehicle and a handle pivotally mounted on the bezel for opening the door. The bezel and/or door has a main portion of a hard rigid material and an outer surface portion of a resilient material.

Abstract: An adjustable door strike having a striker plate (2), a main body (10) and a slider plate (16, 26, 32). The main body (10) is affixed to a door jamb with the slider plate (16, 26, 32) between the door jamb and the main body (10) and adjustably mounted for receiving a standard striker plate (2). The main body (10) is provided with an elongated aperture (12) in the vertical direction which permits the striker plate (2) to have a continuous range of adjustments in the vertical direction. Also described is a mounting template (50) for facilitating the installation of a door strike. This invention allows for mounting a door lock with either or both a latch and a deadbolt without adversely affecting the door jamb in any way.

Abstract: Disclosed is an improved fastening system for attaching a wheel to the frame of an in-line roller skate. The system includes a fastening plug insertable into the axis aperture in the side rail of an in-line roller skate frame. The system further includes a snap cover assembly including an anchor insertable into the axle aperture of the side rail from the other side thereof, a nut insertable into a receptacle disposed in the anchor, and a snap cover for enclosing and covering the nut.

Abstract: A flap is inserted in a similarly shaped and sized tubular opening with the aid of a tool, slots in the flap being engaged by hooks on the tool and being entrained thereby. The tool is inserted into the opening with the flap, and upon withdrawal of the tool, the hooks automatically disengage from the slots so that flap remains within opening. The flap and the tubular opening constitute opposite ends of part of a disposable paper hat.

Abstract: A cage and roller assembly in a hardened thrust bearing race is restrained within the race by heating a plurality of circumferentially widely separated parts of the race lip to soften the lip parts and bending the softened parts over the cage of the cage and roller assembly. An apparatus for assembling the thrust bearing includes a pair of electrodes located to apply a current through the lip to soften the lip and a form punch which is constructed to bend the softened part of the lip over a cage and roller assembly to an acute angle with respect to the rest of the lip.

Abstract: Herein disclosed is a method of assembling a seat slide device which comprises a lower rail, an upper rail slidably disposed on the lower rail and rotating members disposed between the lower and upper rails. The method comprises by steps: (a) temporarily assembling the lower and upper rails; (b) disposing the rotating members between a space defined between the temporarily assembled lower and upper rails; (c) pressing the temporarily assembled lower and upper rails against each other with a given pressing force; (d) making a relative longitudinal movement between the temporarily assembled lower and upper rails with the pressing force kept applied thereto; and (e) removing the pressing force when the relative longitudinal movement counts a given number.

Abstract: A window operator has a base with an upstanding pivot pin having a bushing thereon and at least one component pivotally mounted on the bushing. The components are held in assembled relation by a captured washer and the washer has an outer annular portion formed to provide a controlled clearance. A method of forming the window operator comprises assembly of the pivot pin, bushing and pivotal component to a mounting base and the capturing of a washer beneath the head of the pivot pin and with an inner annular part of the washer engaging an upper edge of the bushing which extends beyond the upper surface of the pivotal component, followed by a deformation of the outer annular part of the washer to compress the pivotal component between the washer and the base followed by release of the compressive force to permit spring-back of the outer annular part of the washer to provide the controlled clearance.

Abstract: A portable sheet metal joining apparatus is disclosed including a releasable tool carrying cartridge carried by a piston in a hand held gun which is powered by a booster of very compact design which uses standard compressed air to create high pressure hydraulic fluid to activate the gun.

Abstract: A fastening system including a two piece swage type fastener including a pin and a collar adapted to be swaged into lock grooves in the pin and in which the lock grooves are helical and with the collar having a limited female thread which is threadably engageable with the helical lock grooves for variably clamping work pieces to be secured prior to swage, with the collar thread being deformable in response to a relative axial load between the pin and collar at the initiation of the swage operation but prior to swaging and in which the lock grooves are shallow and have a ratio of (h/Du).times.10.sup.2 of four (4) or less and in which the lock grooves have a simulated streamlined root contour, with the collar having a wall thickness defining a volume of material sufficient to provide overpacking of the shallow grooves of around 16%, and with the pin and collar materials having ultimate shear strengths in a ratio of around 1.8:1 to 2.

Abstract: A rotatable cutting bit shield and method and apparatus for attaching the shield onto cylindrical cutting bit shafts uses an annular metal ring having the shape of an inverted dish, and a centrally located hole through the ring. The diameter of the hole is initially larger than the diameter of the cutting bit shank. Compressive pressure exerted on the annular upper and lower faces of the ring by the apparatus according to the method causes the ring to deform into a flatter, more disc-shaped structure. This deformation causes the diameter of the central hole in the ring to shrink, captivating the ring axially between larger diameter annular flanges on the cutting bit shank.

Abstract: A load binder includes a lever and a clevis each being connected to respective securing members for securing to a load or a tie member such as a chain or a rope. Each of the securing members includes a retaining member for retaining a swivel bolt. The swivel bolts are cast in one piece with a head and a shaft. The retaining members are also cast with an opening of suitable size and shape to receive the heads of their respective swivel bolts. While the retaining members are still at an elevated temperature from the casting process, the head of the swivel bolt is inserted through the respective openings and the retaining members are then deformed while at an elevated temperature to capture the respective heads of the swivel bolts.

Abstract: A method of fabricating a spline drive including the steps of providing an elongated rod of indeterminate length having axially extending splines thereon, cutting a cylindrical member of predetermined length from the elongated rod, turning the cylindrical member at its end to provide splines of reduced height and shoulders at the junctions of the reduced splines and the original splines, broaching a washer to provide an internal surface of complementary mating relationship to the turned end of the cylindrical member, mounting the washer on the turned end with the side of the washer abutting the shoulders, laser-welding the washer to the cylindrical member, and brazing a drum to the washer.

Abstract: An adjustable ironing table (10) includes a top board (12) and collapsible legs (22,24). A housing (46) has a vertical wall (48) extending perpendicularly relative to the top board (12) and a horizontal wall (50). The vertical wall (48) includes an opening (52) for guiding a control element (36) through the housing (46). The horizontal wall (50) includes a slot (54). A plate (44) extends through the slot (54). A compression spring (42) is retained by the control element (36) between the vertical wall (48) and the plate (44), the spring (42) pivoting the plate (44) relative to the slot (54) to engage the control element (36). The top board (12) includes a peripheral flange (20) having an outwardly curled periphery (78). The top board (12) further includes flat stretched portions (16) extending along the length of the top board (12). One of the legs (22) is connected by a base member (92) to guide rails (74), the base member (92) having four point containment of the guide rails (74).

Abstract: A self-locking nut is provided having, at its periphery, a number of longitudinal channels (3) with semi-circular section intended to cooperate with drive balls carried by an appropriate tightening tool, said balls causing, at the end of tightening, the formation of a circular groove (10) by forcing back the metal situated between the channels (3), which results in radial deformation of the inner threads of the nut (1) at the level of said groove (10).

Abstract: An improved shoe for a structural support and an improved method of forming the same wherein rigid angular parts have the base members positioned in cooperative reinforcing relation and joined together with the side members extending in opposed faced and spaced relation to each other to form the structural shoe.

Abstract: A blind fastener of the type having a fastener body, a threaded stem and a sleeve is provided with a deformable drive nut in abutting contact with the fastener body to provide a positive mechanical engagement between the abutting surfaces of the two elements. The underside of the drive nut has an annular ridge made of a deformable material adapted to deform into indentations in the outer surface of the fastener body. The positive mechanical engagement between the two elements minimizes the build-up of tensile load applied to the stem during setting of the fastener.

Abstract: Method for securing a wire in its tensioned condition in a wire driving type window regulator comprising a carrier plate to which a window glass is secured mounted on a pair of guide rails, a raising and a lowering wires each one end of which is secured to the carrier plate and each intermediate portion of which is inserted into an outer tube, said wires being moved up and down directions along a reciprocal passage running partially along the guide rails by a driving means, is carried out by boring a guide hole on either of supporting plates which support the guide rails into which a tube end plug is slidably inserted, and after then the tube end plug is pressed in the tensioned direction of the wire, and an edge of an opening of the guide hole being cut to make a cut piece which is erected so as to maintain the tensioned condition of the wire.

Abstract: A chain net comprises a plurality of warp strands (1.1) with mutually equal links (1.2) which at intersections lock round links (1.5) of weft strands (1.4) having mutually equal links. The links of the warp strands have dimensions such that they first allow the insertion of weft strands and, after plastic or elastic deformation, lock links of the weft strands. The plastic deformation is provided by elongating the warp strands. The elastic deformation is provided by the warp strand links being first expanded to allow the insertion of weft strands, after which the warp links are elastically re-deformed for locking round weft links.

Abstract: A paper perforating device for creating a series of linearly aligned perforations the length of a sheet of paper. The invention includes a lower member with a series of linearly aligned openings and an upper member with a corresponding number of linearly aligned teeth. Upon engagement, the teeth travel through the openings thereby piercing the paper. The invention also includes a pair of slot-engaging tabs which limit the distance the upper and lower members may travel relative to one another.

Abstract: An improved surgical device and method for manufacturing the device are provided. The device is a high rotating speed arthroscopic probe shaver with bearing means that give superior longitudinal and radial support. Further, the outer tube of the probe shaver is swaged to fit very closely over the inner tube.

Abstract: A captive panel fastener includes a head, a shank and a threaded outer end, with slots extending longitudinally down through the threads towad the outer end of the fastener. A relatively rigid and inflexible retention washer is provided and this washer has inwardly extending prongs which fit into the longitudinally extending slots on the fastener. The outer end of the fastener has a hole in it, and, after the washer is in place, a forming tool is employed to deform the outer end wall of the opening, so that the wall is pushed outwardly to block the outer ends of the longitudinally extending slots, thereby holding the washer onto the fastener, and retaining it extending through a hole in a panel or the like through which it may have been inserted. A small washer may be employed at the end of the fastener between the ends of the slots and the deformed extreme outer end of the fastener.

Abstract: The present invention relates to a plug-containing type internally threaded anchor to be set in concrete which is used to optionally and firmly fix hardware, such as ceiling members, floor members and wall members, to the surface of a concrete structure and it also relates to a method of producing the same which promises mass-production effect. The invention is characterized in that as a means for preventing the plug contained in the anchor body from accidentally slipping off owing to vibration, shock or other external forces exerted during transport or laying operation, the anchor body is formed with an internal thread by rolling whose internal diameter is smaller than the outer diameter of the plug, so that the crest portion of the internal thread bulging by a predetermined amount above the anchor body holds the plug in slip-off preventing condition.

Abstract: The specification discloses a self-contained ball bearing for use in drawer rails. The bearing includes balls axially retained between a flared end of an inner race member and a washer retained on a stem of the inner race member. The bearing further includes a polymeric outer race member having a thrust shoulder extending radially inwardly closely proximate the flared end of the inner race member to form a dirt shield therewith and to provide an improved thrust bearing surface.

Abstract: An anti-static switch lock wherein a terminal assembly having the desired configuration of rotor and contacts is secured to one end of a hub. The other end of the hub has an inboard lipped boss forming, in cooperation with the hub end, a circumscribed radial groove. A keylock assembly includes a barrel, one end of which has a chamber to receive the boss of the hub, and a key operated, rotatable plug. The hub, having the terminal assembly attached to one end, is positioned such that the groove is disposed within the chamber of the barrel. A number of stakes are formed in the barrel, the stakes engaging the groove to firmly secure the hub to the barrel. The plug is inserted into the barrel, the end of the plug interlocking with the shaft of the terminal assembly rotor to effectuate switching of contacts.

Abstract: Method for forming roller bearing cage lugs into roller retainers. Portions of the lugs provided on bearing cage webs are staked to a preselected depth and a desired retainer conformation in an overlying relationship with adjacent roller receiving pockets in the cage. A punch assembly which accommodates a pair of simultaneous staking operations is employed. The assembly includes a staking punch configured to stake portions of the same lug in opposite directions from each other overlying portions of adjacent receiving pockets or to stake portions of adjacent lugs in opposite directions toward each other overlying opposed sides of the same receiving pocket.

Abstract: A hip prosthesis comprises a one piece element including a head, a plate portion, a neck interconnecting the head and plate portion, and a flexible femoral rod which includes thin longitudinal elements extending away from the head in opposition to one another. The longitudinal elements are obtained by providing at least a longitudinal cutting in the rod which extends to its end opposite the head. A slot in each end coincident with the cutting houses a linking part for holding the elements together in one plane while permitting their relative movements in a second substantially orthogonal plane. The elements are made in one piece with the head, the neck and the plate of the prosthesis, with the rod itself being forged from a single piece.

Abstract: A collapsible steering shaft assembly incorporating a slide with deforming balls that roll tracks in telescopic shaft members so that the shafts are positively interconnected in a rotational sense and which roll in said tracks to permit relative sliding of said shaft on application of low axial load.

Abstract: A scheme for accurately and quickly axially positioning a rotatable member such as the axles of a differential or a shaft supported impeller of a centrifugal pump within a housing or similar support for rotation therein with predetermined axial bearing clearance which is independent of the dimensional variations of the member and support is disclosed wherein a deformable spacing element is associated with each thrust carrying bearing with the adjacent bearing and spacing element being held axially captive between the shaft and a corresponding disc which is slidable relative to the housing and with one disc axially aligned and limited in sliding movement on one common direction opposite the direction from which the rotatable member is positioned by engagement with the housing. Typically there are two discs, one limited in movement toward the interior of the housing and the other limited in movement by the means of encapturing the rotating assembly.

Abstract: In a shock absorber unit for vehicles of the double-tube type a piston rod guiding member is provided at respective first ends of a cylinder and a container surrounding the cylinder. The first end of the container engagingly surrounds a radially outer face of the piston rod guide member. The container is tube-shaped and has substantially constant wall thickness along its total length. The radially outer surface of the piston rod guiding member is provided with at least one radially inward directed recess or at least one radially outward directed projection. The first end of the container is deformed such as to engage this projection or recess respectively. A sleeve member engagingly surrounds the first end of the container. This sleeve member is also provided with a deformation which deformation is in engagement with the deformation of the container.

Abstract: There is provided a method of assembling an anti-sweat heater in a refrigerator cabinet that includes forming the outer case of the cabinet with a sidewall and front face having a right angle corner therebetween and a flange spaced from the corner and inwardly turned from the front face with a depending lip extending towards and spaced from the cabinet sidewall. A heater retainer member is formed and has a portion thereof in cross section view with a front end shaped to receive the heater, a straight center section and two flexible wings, one on each side of the center section and diverging from the center section away from the front end, and also a rear end. The anti-sweat heater is placed in the front end of the retainer member and the heater and front end and center section including the wings of the retainer member are inserted through the space between the depending lip of the flange and the cabinet sidewall.

Abstract: Therein is disclosed a method for assembling a uniform-speed joint having an inner rotary body and an outer rotary body which transmits a rotational force from one to the other through a plurality of small spheres in receiving holes on the disposed outer peripheral surface of said inner rotary body and including a pair of small spheres diametrically facing each other where the intersecting angle between the rotation axes of said inner rotary body and said outer rotary body is variable and the rotational speed is not changed.

Abstract: This invention pertains to bail applying mechanism particularly for plastic containers with molded-on ears with access openings to the interior of the ear. These plastic containers are usually provided with wire bails when the container is empty. These plastic containers may have their body formed with a taper. "Shingling" of tapered containers is prevented by a guide rail disposed immediately above the transported containers. This guide rail extends through the bail applying station. A backup is also provided when and where the plastic container is provided with molded-on ears having an access opening. This bail applying mechanism may also be used with metal containers with attached sheet metal ears which may be absent apertures for the wire bail or the apertures may be mispositioned if present.

Abstract: A pneumatic spring counterbalance extensible link including a closed end cylinder with an end connector a piston and rod assembly within the cylinder and maintained therein by the crimped over end portion of the cylinder retaining a rod bushing and rod to cylinder seal. The cylinder is pressurized prior to assembly of the complete piston and rod into the cylinder. The piston assembly includes orifice by-pass means either in the piston periphery or in a piston ring, and the piston may include a fail-safe provision in the event the orifice is clogged. A crimping die assembly is used in assembling and completing final assembly of the counterbalance components while simultaneously maintaining the link in a pressurized environment, utilizing sealed arrangement between the crimping dies to maintain pressurization of the interior of the dies and the counterbalance components prior to assembly of the components.

Abstract: A method of fabricating a hand calculator utilizing die press punching to form its three parts. A circular stationary base plate is punched with a central, circular, raised, beveled portion which is then rigidly fixed to a circular stationary top plate by means of flared eyelets. Between these two parts a circular movable scale plate is movably inserted. The scale is etched with scales, and punched with a plurality of holes about its periphery to allow for pencil point movement.

Abstract: The self-locking threaded bearing is an externally threaded tubular member having a discontinuous thread to form thread sections which are spaced-apart axially on the bearing. In the bearing assembly, the thread sections engage portions of an internal thread in a bore of a housing for the bearing and, with the internal thread being more ductile than the thread sections of the bearing, portions of the internal thread are stripped to pack into the space between the thread sections and assist in locking the bearing into the housing.In the method of making the self-locking threaded bearing assembly, a tubular bearing is provided with a discontinuous external thread and a housing is formed with a bore having an internal thread of the same pitch as the external thread of the bearing and of material more ductile than that of the external thread.

Abstract: An adjustable ironing table (10) includes a top board (12) and collapsible legs (22,24). A housing (46) has a vertical wall (48) extending perpendicularly relative to the top board (12) and a horizontal wall (50). The vertical wall (48) includes an opening (52) for guiding a control element (36) through the housing (46). The horizontal wall (50) includes a slot (54). A plate (44) extends through the slot (54). A compression spring (42) is retained by the control element (36) between the vertical wall (48) and the plate (44), the spring (42) pivoting the plate (44) relative to the slot (54) to engage the control element (36). The top board (12) includes a peripheral flange (20) having an outwardly curled periphery (78). The top board (12) further includes a flat stretched portions (16) extending along the length of the top board ( 12). One of the legs (22) is connected by a base member (92) to guide rails (74), the base member (92) having four point containment of the guide rails (74).