Abstract: A setting cable retainer device for aligning and securing precast sections in an excavated shaft of a water well or the like, the device having a receiver guide unit secured to or cast in the section and a cable retaining strap which upon proper engagement with the guide unit with a cable therebetween locks thereto to provide an opening through which the cable can slide.

Abstract: A tool for the removal of lead wire boots from the spark plugs of internal combustion engines. The tool has an L-shaped steel hook adapted to engage the underside of a spark plug boot and permit its removal by an upward pulling of the tool. The tool has an elongated silicone elastomer handle molded integrally to the steel hook through openings in a shank thereof. The thick rubber-like silicone handle fully electrically insulates the user from the hook and thus also the high voltages carried by the spark plugs. The handle is sufficiently flexible to permit the user to insert the tool through the maze of appurtenances of the present day crowded engines into the area of the spark plugs. The flexible handle is endowed with sufficient strength to pull the spark plug boots and is equipped with a flat circular ring for easy gripping by the user and for conveniently hanging on a hook when the tool is not in use.

Abstract: A machine for manufacturing high strength flexure hinges having use in accelerometers. A source of metal material is splat-cooled after it has been heated to a molten state. An induction heater heats the metal material to the molten state and the molten metal is rapidly cooled while being pressed between two water cooled wheels. The wheels are provided with indentations and protuberances on their surfaces to produce flexure hinges and strengthening beams. A chute is provided to catch the flexures as they leave the wheels preventing damage to them.

Abstract: A curvilinear cradle for supporting an object such as a pipe has a durable polyurethane elastomer lining on its concave surface to thereby prevent wear due to movement of the supported object. The cradle also has at least one mounting bracket attached to its convex surface for securing the cradle to a base object such as a pipe H frame.A method for making the curvilinear support cradle primarily includes the steps of spinning a pipe along its longitudinal axis, bulk injecting a polyurethane elastomer into the spinning pipe to create a centrifugally spin casted coating on the inner surface of the pipe, and cutting the pipe lengthwise to obtain at least two lined cradles. Preferably one or more mounting brackets are attached to the pipe prior to the step of spinning, and the pipe is transversely divided on each side of the mounting brackets to provide a plurality of relatively shorter cradles.

Abstract: When constructing an electrical or electronic device or mechanical device such as a tape recorder, the framework therefor must be provided with various projections for installing various components to be contained therein, or something such as a spring for actuating the mechanism incorporated thereon must be previously provided on the framework. The present disclosure relates to such projections which are made of synthetic resin which can be integrally formed on a metallic plate during the step of molding and also to such molded projections which are not deformed by the shrinking of the synthetic resin when molded integrally with the plate to form the framework.

Abstract: A single automatic part insertion machine which can insert the leads of various electronic components such as resistors, IC chips, IF transformers, variable resistors, connectors and so on, into specified insertion or mounting holes of printed circuit boards. The boards are supported on a common set of conveyor rails in one row, and are displaced in X and Y coordinate directions while they are transferred from a feeding position to an unloading position. Specified lead insertion holes of specified printed circuit boards are thus aligned one at a time with selected units of a number of parts feeding means in a predetermined sequence, so that the leads of corresponding electronic components may be inserted into specified insertion holes of the printed circuit boards and clinched if required. An automatic unfinished printed circuit board loading device is provided, as well as an automatic finished printed circuit board stacking device.

Abstract: A low cost scraping implement has a wooden or plastic handle with a recess in one surface. A square of plate glass, metal or plastic is held in the recess by a wood retaining plate. A carriage bolt is received in aligned openings drilled through the handle member and the retaining plate. A wing nut threaded onto the shank of the carriage bolt draws the retaining plate towards the handle member to clamp the glass square in place. The glass square can be repositioned within the recess to present eight different scraping edges. A worn or broken glass plate can be readily replaced to renew the scraper.

Abstract: A grass cutting attachment for an electrically powered handyman's drill is disclosed. A length of flexible filament extends radially from a body rotatable by the drill. The rotating filament end is able to cut both edges of lawn and expanses of lawn. A handle attachment which prevents stooping and bending by an operator is also disclosed.

Abstract: A table knife in the form of a hockey stick providing a straight cutting edge which engages the food to be cut over its entire length when the handle is held at a normal angle. Cutting efficiency is increased.

Abstract: A portable chain saw having a drive-part assembly including an engine, saw chain and so forth, and a supporting assembly including a front and a rear handles and so on. These two assemblies are resiliently connected to each other through a plurality of tubular resilient connecting members. Each of the tubular resilient connecting members carries at its outer peripheral surface one of the two assemblies, and is connected to the other assembly through a screw or a bolt received by the bore thereof.

Abstract: A prosthetic element such as a dental prosthesis, is retained in position by a magnetic device which is attached to a seating or foundation structure which is permanently fixed, preferably by keying, in a cavity in the bone. The magnetic element may be releasable from the seating or foundation structure.

Abstract: A method of cushioning and retaining a dental plate that eliminates the need for adhesives and provides the wearer a choice of thicknesses that is for all practical purposes continuous. A denture cushion according to the present invention comprises one or more sheets of cellulose filter material. The sheet periphery is shaped to cover the gum and palate confronting portions of the plate, and fits in the region between the plate and the wearer's mouth. A cushion for the lower plate has a U-shaped configuration while a cushion for the upper plate has a generally rounded or oval configuration, preferably with a plurality of peripheral notches to make the cushion more easily conform to the contour of the wearer's palate. In use, the wearer places a number of such sheets in a stack to make a cushion of the appropriate thickness and moistens them.

Abstract: A rigid bar arranged to removably support an artificial denture is curved in the shape of the lower jaw bone and has front implant support means as well as rear ramus implant portions. Each of the ramus implant portions includes a tip end of the frame arranged to be inserted in a rearwardly extending opening cut in the jaw bone by the dentist. Such tip ends have laterally extending flattened portions which provide increased bearing support on the jaw bone. The front implant support comprises a depending extension arranged to be inserted in a recess cut in the top surface of the jaw bone, and such extension has a cross blade with one or more forwardly extending tabs arranged to seat on surface portions of the jaw bone. The cross blade may also have rearwardly extending tabs arranged also to seat on surface portions of the jaw bone.

Abstract: Force-transmitting means serve to exert a correcting force on at least one tooth of a patient and comprise an elongated first element and at least one second element. At least one clamping sleeve resiliently clamps itself on said first element and engages said second element and has a radially inwardly tapering longitudinal slot, which is adapted to receive an implement which is operable to widen said slot so that said clamping sleeve is slidable along said first element.

Abstract: A plastic shank holding a metal dental anchor therein is disclosed, wherein the dental anchor is for anchoring a superstructure to a tooth. The dental anchor includes at least one threaded section and one manipulating end section joined together by a frangible portion so that the sections can be severed. The shank includes an opening for receiving the manipulating end section of the dental anchor in a force-fit connection therebetween, where the manipulating end section includes torque transferring wing portions for permitting the shank to pivot relative to the dental anchor when the dental anchor is being threaded into a channel in a tooth. A plastic hand driver is provided for receiving the shank therein, where the hand driver includes an abutment portion for rotating the shank, and projections for providing a snapped-in connection between the shank and the hand driver to permit a pivotal relationship therebetween while releasably retaining the shank within the hand driver.

Abstract: A device of this invention for opening and closing a chuck for a dental handpiece comprises a housing and an output shaft rotatably journalled in the housing. A cylindrical hollow is formed axially from a top end portion into the output shaft and a plurality of openings are formed at equally spaced portions around said shaft near an innermost portion of the hollow. A truncated cone-shaped column having a conical surface is firmly inserted into the innermost hollow of the output shaft to define a space for a small metallic driving ball. The small driving ball is rotatably inserted into each opening of said output shaft, and a large metallic driven ball is rotatably inserted into the hollow to abut against these small driving balls. A ball control sleeve having a tapering inner periphery is slidably fitted on the output shaft to locate at the openings.

Abstract: A matrix band guide for use in simultaneously applying a matrix band to a plurality of teeth. The guide is a flexible elongated member having a plurality of slots. The elongated member is of sufficient length and of sufficient width to allow placement of the guide against the teeth and to guide the matrix band around the teeth. The slots are of a width, height and spacing sufficient to permit the looping of the matrix band through the slots to form a plurality of loops for binding engagement with the teeth. When the matrix band is drawn into binding engagement with the teeth, the elongated member and the matrix band substantially conform to the taper and curvature of the teeth.The guide, may have a mounting means for mounting the elongated member to a conventional matrix retainer in such a manner that the matrix band can be drawn into binding engagement with the teeth by the conventional matrix retainer.The elongated member may also be shaped to substantially conform to the alignment of the teeth.

Abstract: A chemical HCl or DCl laser is obtained by irradiating COCl.sub.2 +H.sub.2 D.sub.2 in admixture with the P.sub.54 line of a CO.sub.2 laser. The irradiation is accomplished in a laser cavity provided with appropriate Brewster windows, mirrors, and coupling means. The COCl.sub.2 is mixed with H.sub.2 or D.sub.2 in a properly conditioned system without reacting. The irradiating by the P.sub.54 line of a CO.sub.2 laser dissociates the COCl.sub.2 to form CO+2Cl* (Cl*-atom in an excited state). The Cl* atom then reacts with H.sub.2 /D.sub.2 present to produce HCl or DCl in an excited vibrational state. The halogen containing molecule then lases.

Abstract: A brush guide for guiding a brush to provide for the painting of a continuous line, the brush guide comprising an elongated body including a continuous edge and at least two support legs extending from the body, each leg defining a flat base portion, the legs defining an elongated space therebetween, the base portion of the legs being offset from a vertical projection of the edge to accommodate the brush during painting.

Abstract: The gauge has a plurality of laterally spaced pairs of hollowed frustrums. Each pair of frustrums is spaced in accordance with the distance between the lugs comprising standard lug patterns on existing hubs and wheels of automobiles. The hollowed frustrums may be placed over adjacent lugs on the hub of an automobile to determine the actual spacing therebetween. Furthermore, the frustrums may be inserted in adjacent openings in automobile wheels to determine that spacing and thereby enable the user to match a wheel to the hub upon which it fits.

Abstract: A member having an axis to be positioned in an opening whose axis may be displaced from the member axis is connected by three rods, wires or wire ropes equally spaced about the axis secured to a supporting plate and having a first portion generally perpendicular to the plate and a second portion extending downwardly from the first portion with the lower end closer to the member axis than the upper end with the first portions allowing translation of the member and the second portion allowing rotation of the member to enable the member to be aligned in the opening as the upper support member moves downward toward the opening. The rods, wires or wire ropes may be separated by a spreader and reside within an elastic body with damping and be preloaded in tension or compression.

Abstract: An apparatus and method for marking points and lines during building construction, includes a layout tool having a plurality of elongate members adjustably secured together for axial extension relative to one another to different lengths, the members defining a tubular body in which a pendulum or plumb rod is suspended for indicating when the tool is vertical in a first plane, and having a level thereon for indicating when the tool is vertical in a second plane perpendicular to the first plane, and pointers at the top and bottom ends of the tool, for alignment of one of the pointers with an existing line or point, whereby another line or point may be marked at the other pointer after the tool has been made vertical in both planes, the plumb rod being enclosed within the tubular body and thus being unaffected by wind. Chalk line holders are included for marking a line after the points have been determined. The method of marking points and lines using the apparatus is also disclosed.

Abstract: An attachment is slidably engaged with the blade of a caliper-type measuring device. The attachment carries a contact element which is sized to be inserted into the groove between adjacent threads and abut each thread. The pitch diameter of threads are measured by opposed attachments carried by the respective blades of the calipers. Axial alignment of the contact member within the thread groove is accommodated by sliding arrangement between the attachment and the blade.

Abstract: Azimuth and elevation adjustments in a geodetic instrument are provided by systems which include coaxial locking and two-speed adjustment control knobs. In each such system, the control knobs are accessible at both the front and rear of the instrument to facilitate operation in either of the forward- or back-sighting mode.

Abstract: A drafting aid comprising a flat board, the board having two straight parallel edges and guide surfaces at the parallel edges. A flexible member passes about the board and over the guide means. The flexible member includes resilient tension members extending between the end edges thereof to form a taut member about the board.

Abstract: Process for the uniform pre-drying of damp textile material webs, subsequent to a continuous wet treatment operation, including measuring the moisture content remaining on the textile material, wherein, in the course of the material run, immediately behind an infrared pre-drying tunnel for the continuously fed material, several measuring positions are arranged transversely to the transport direction of the material, and measurements of the residual moisture are made by means of a contactless method, determining measuring pulses in this manner and transmitting these to the control elements of the preceding pre-dryer and within the heating power is controlled of several separately controllable heating fields, distributed across the width of the drying tunnel, in agreement with the measured values of the moisture.

Abstract: A paper machine drying section and method for operating the same are provided for reliably maintaining a web in engagement with a drying fabric at locations where the fabric is situated between the web and drying cylinders. Those drying cylinders which are directly contacted by the drying fabric, so that the web is separated therefrom by the drying fabric, are formed with recessed outer surfaces having voids across which the fabric extends. The pressure in these voids is maintained at a magnitude less than the pressure at the outer surface of the web where it travels around those cylinders from which it is separated by the fabric, so that in this way the web is urged by the pressure differential toward the fabric so as to be incapable of becoming detached therefrom.

Abstract: A training device for teaching individuals the proper positioning of a sailboat's boom relative to the boat in a given wind. The device has three planar members, a front (base) member indicating wind position and having sailing terms printed therein, a second planar member representing the boat and a third planar member representing the boom of a sailboat. Three axis members interconnect the planar members for proper relative rotation. The first axis member secures the free end of the boom to the base member. The second axis member fixes the second planar (boat) member for rotation about the base member. The third axis member fastens the front end of the third planar (boom) member to the second planar (boat) member and allows some relative rotation.

Abstract: The apparatus comprises in combination with a support having a butt, a trigger and a device defining a line of sight, an image recording apparatus. A device forms the image of a cross-wires and a magnifying optical device whose optical axis is roughly parallel to the line of sight with a very small parallax is combined with the image recording apparatus to form an image therein. A connecting and actuating device actuates the release of the image recording device. The arrangement is such that the picture is taken by the image recording apparatus with a delay which is equivalent, in a real rifle, to the time that elapses between the actuation of the striker and the issue of the projectile from the barrel and it is completed by an interpreting device whereby it is possible to ascertain the precision of the aim and effect the necessary correction.

Abstract: A tread for a sport shoe which includes a sole having projections extending outwardly from a tread surface. The tread includes a one-piece, thin-walled, metal part with at least two separate, dimensionally reinforced surface sections bearing the integrally molded projections. The reinforced surface sections may include a plurality of embossed, smooth-surfaced and/or bevelled projections. The metal part is fixedly attached to an inner surface of the shoe sole by either a thin wire grid embedded in the synthetic resin sole or uniformly distributed perforations.

Abstract: A shoe, more particularly for toddlers, comprises at the back, from bottom to top, successive zones of decreasing rigidity and increasing flexibility, namely a first zone comprising, from inside to outside, a soft lining, a foam filling, an inner reinforcement, a flexible body and an upward extension of the outer sole; a second zone comprising, from inside to outside, the soft lining, the foam filling, the inner reinforcement and the flexible body; a third zone comprising, from inside to outside, the soft lining, the foam filling and the flexible body; and a fourth zone comprising a foam cushion surrounded by the soft lining. The sole preferably also comprises an upward extension at the front. The foot is perfectly protected and supported, very comfortably and softly.

Abstract: A snowmobile trail groomer, having a main cab for seating the driver, steering and control means for operating the groomer, a steerable ski at the front of the groomer, spaced from the main cab for steering and control purposes, an adjustable and tiltable blade disposed between the ski and cab, the drive means having an engine and track means comprising bogies and an endless track supported on either side of the cab, the bogies being secured within the track for driving the endless track, the track means being pivotally connected to the cab at a position on the cab for relative pivotal movement with respect to the cab, the engine for driving the bogies for driving the track, and substantial weight mounted on, and supported by, the steerable ski.

Abstract: A waterway cleaner comprising a hull supporting an extendable and swingable ladder mounted at one end, or bow, of the hull, a power driven endless chain of spaced scoops mounted on the ladder for scraping and excavating material from the bottom of a waterway and a belt conveyor on the deck of the hull extending beyond the stern of the hull for moving material dumped from the scoops to a dump scow. A pair of cables wound on power-driven winches, mounted one on each side of the hull, are used to displace the hull to a selected location on the waterway. A scraper is mounted vertically swingable around a pivot proximate the stern from a raised position to a submerged position in engagement with the waterway bottom. A pair of vertically movable legs positioned one on each side of the hull are adapted to engage the waterway bottom to stabilize the hull and maintain it in a fixed position. The scoops, conveyor and winches are operated by hydraulic motors.

Abstract: The invention is an identification card that displays a finger or thumbprint pattern to confirm the user's identity. The card contains a sliding transparent window that slides from a concealed, non-use position to a visible position where the user can place his fingerprint on the window. When the window slides from the visible position to the concealed position, a wiper in the card cleans the residual print from the window.

Abstract: A modular, graphic display and storage member provides for the attachment of photographs in a curved fashion for ease of viewing, attachment and removal. A number of fins are snap fitted to a central core member so that they may be easily removed by swinging the fin in an arc. Photographs are held in place between the outer end of pairs of fins with reversely positioned claws located at the end of each fin. The module, as assembled, may be used singularly or may be mounted in tandem on a spindle and allowed to rotate for ease of viewing and for decorative purposes.

Abstract: A self-supporting plate for holding photographic slides includes a unitary plate having a plurality of depressions spaced apart in lateral and longitudinal relationship and surrounded by two side partition walls and two end partition walls and having a substantially flat bottom wall. Each depression is adapted to receive a photographic slide therein. The self-supporting plate further comprises projections provided on and along part of the opposite side surfaces of the side partition walls, the projections being adjacent to one of the end partition walls in parallel spaced relation to the flat bottom and projecting inwardly of each depression. A groove is provided in the flat bottom of the depression between the mutually opposing projections of each depression, with its opposite side partition walls positioned on the opposite sides of a line on the bottom wall of the depression in parallel thereto.

Abstract: A relatively thin thermoplastic sheet material, vacuum molded to form a sign letter base including hollow wall members and hollow light-fixture supports upstanding from a single-thickness horizontal bottom member. The base inverted forms a mold itself for receiving a flexible plastic foam inserted to a suitable height and disposed within the vertical walls and fixture supports for providing compressible elasticity to the thin molded sheet in predetermined locations for enabling cooperative interaction of the same with retainer members used to secure a display sign face and gas filled lighting tube structures in proper location onto the base. A rigid polyester resin is cast as a ring encircling the letter walls, located and supported by the flexible foam to stabilize and support the thin nature of the base.

Abstract: An improved cartridge loader of the type having a generally star shaped latch that cooperates with cartridge bores positioned within a casing. A first novel feature is a semi-automatic rotation device for the star shaped latch, which device causes rotation of the latch from a cartridge capturing position to a cartridge releasing position in response to an external force directed axially against a knob when the casing is restrained against rotational motion, and which device will not induce rotation of the latch unless the casing is so restrained. The semi-automatic rotation device is also manually operable to set the latch from the releasing position to the capturing position, and to return the latch from the capturing position to the releasing position, simply by manually rotating the knob.

Abstract: A fishing rod holder comprising a bracket and a rod holding member pivoted on the bracket for movement about a generally horizontal axis. A pair of spaced electrical contacts are provided on the rod holding member and a tensioning arm forms a third contact adapted to be normally engaged by the rod holding member at a point intermediate the spaced first and second contacts. The tensioning arm is yieldingly mounted on the bracket and is connected electrically to a signal device which in turn is connected to the pair of contacts such that when the rod holding member is moved in one direction or another relative to the bracket, a predetermined distance, a circuit is completed through the tensioning arm to energize the signal means.

Abstract: A detecting apparatus that is mountable remote from a fishing rod for monitoring fish strikes. The detecting apparatus includes a rod and line engaging means that is attachable to a portion of the fishing line or rod that experiences movement upon a fish strike. Coupled to the engager means is an insulator which is normally positioned between contact pieces of an electrical indicator circuit, but is pulled from between the contact pieces to energize the circuit in response to movement of the engager means when the fishing line is struck. Upon a fish strike, the engager means further completely disengages from the fishing line or rod, permitting the rod to be used without the hindrance of the strike detector apparatus.

Abstract: A fishing lure having two bodies connected together such that the bodies rattle against each other as the lure moves through water. Each body comprises a metal plate bent to form a front portion and a back portion. The back portion has a longitudinal bend so that each side of the back portion extends slightly downwardly to the side edge thereof. The front portion is bent upwardly with respect to the back portion. The front portion has a longitudinal bend wherein each side extends upwardly to the side edge thereof. The front and rear portions of each metal plate have conforming shapes so that the top plate nests in the bottom plate. The front portion of the top plate is bent at a greater upward angle with respect to its rear portion than the upward angle of the bend of the front portion of the bottom plate with respect to its rear portion. Holes extend through each end of each plate.

Abstract: An adjustable float-sinker comprising a body having a specific gravity of the order of that of water and means for varying the volume of the body without changing its mass.

Abstract: An improved insect-combatting device (e.g., for use against houseflies, gnats and mosquitoes) is disclosed. The device comprises a shaped solid body having a porous surface capable of gradually and continually releasing naled insecticide in an amount sufficient to provide an insecticidally active concentration of said naled over a prolonged period of time and comprises a synthetic resinous matrix material, from about 15 to about 35 weight percent of naled and a minor amount effective to retard spewing of the insecticide of finely divided silica particles and at least one C.sub.14 to C.sub.20 saturated aliphatic carboxylic acid or a salt or ester thereof. The device is formed from a mixture of the said synthetic resin, naled, finely divided silica particles, C.sub.14 to C.sub.

Abstract: An amusement device for young children to be mounted on a safety belt in an automobile designed to occupy the child's attention during automobile trips, the device including knobs to be turned and buttons to be pushed. The device includes lights, and a switch that will permit operation of the lights when the device is properly mounted on the safety belt.

Abstract: A toy block unit having a central hub and at least three attachment arms extending outwardly along non-parallel axes projecting from the central hub. At least one of the axes projects out of the plane defined by the other axes. The attachment arms are dimensioned for interconnection with identical arms on adjacent block units, to allow the construction of three-dimensional structures.

Abstract: A hollow structural element has a hollow member having a circumferential wall and a side wall which closes one of the axial ends of the circumferential wall, a cover member arranged to close the other end of the circumferential wall of the hollow member and connecting elements for connecting the structural element with other structural elements. The connecting elements include an undercut projection provided in the cover member and arranged for inserting into an undercut groove of another structural element, and an undercut lateral slot provided in the side wall of the hollow member and arranged for engaging with an undercut projection of a further structural element. The lateral slot has a first enlarged portion through which the projection of the further structural element can pass, and a second reduced portion extending from the first portion toward the axis of the circumferential wall and dimensioned so that the projection of the further structural element engages in the reduced portion.

Abstract: A spinning top comprises a casing in which is located a gear including a vertical shaft extending downwardly from the casing, the uppermost portion of the said shaft being a Z-profiled bar, the sidewardly extending arms of which are in frictional contact with the ends of oppositely disposed horizontal axles turning in seats provided in the inner wall of the casing. On each of the said horizontal axles a crown wheel is keyed, both crown wheels being in mesh with a pinion, the central axle of which is fixedly connected with the uppermost part of the spinning top casing.

Abstract: A water toy for children comprises a plurality of puzzle pieces formed of lightweight, floatable material and each puzzle piece includes one or more contoured edge portions which are shaped to removably interlock with a contoured edge portion of an adjacent puzzle piece like a jigsaw puzzle. The assembled puzzle pieces form the outer profile of an animal or other creature such as a whale, or the like, when they are assembled together with their contoured edge portions interlocked in a proper selected assembled relation. Each puzzle piece is of sufficient thickness so that while the pieces may slide relative to one another due to the water action, they will not become disassembled. Each of the individual puzzle pieces also includes on at least one side, an individual animated face and is shaped to present a particular real or imaginary animal such as a turtle, shark, seal, serpent or other creature.

Abstract: A stuffed doll having a substantially rigid head and upper torso portion, legs hingedly connected at the lower end of the upper torso portion, lower finger receiving pockets at the rear of the legs and a common pouch extending across the open upper ends of the lower finger receiving pockets to form an upper finger receiving opening at the rear of the upper torso of the doll. Arms or other upper limb members are hingedly connected to the upper torso portion and with a leg, to move with the leg.

Abstract: A window structure is disclosed wherein the center portion includes sliding panels which have stiles in abutment in their closed positions, such stiles having plates or ribs extending from their inner surfaces which are captured and releasably held by a latch mechanism that is pivotal on one rib and slidable along it. On the exterior of the structure, one of the stiles carries a plate that spans equal areas of both abutting stiles. The latch is symmetrically contoured, whereby observation from either side of the structure does not clarify the edge portion and direction of movement of such portion of the latch that is required in order to operate the latch and permit the sashes to be moved apart. Further, the exterior plate prevents insertion of a tool between the abutting stiles when the sashes are in closed position and latched.