Abstract: A suspension joining structure includes: a lower arm having one end fastened to a vehicle body; an assist knuckle having a strut thereon; a fastening unit configured to connect one end of the lower arm and a lower end of the assist knuckle to each other; a suspension fastened to the assist knuckle and rotating independently of the assist knuckle for steering of a wheel; a steering input part connected to the assist knuckle, and configured such that a steering force is applied to the suspension upon steering; and a rotation transfer unit arranged between the suspension and the steering input part.

Abstract: An awning system having miter connectors suitable for attaching to portions of T-slot tubing members is disclosed. The awning system can be shipped by conventional shipping mechanisms, does not require welding, and does not require a flat-bed truck for transport. Also, the awning system can then be assembled and installed on-site, rather than being shipped in a fully pre-assembled state. The awning system uses proprietary tubing members and (in most embodiments) a miter connector to form an awning frame.

Abstract: In various representative aspects, an assembly for securing a solar panel rail support structure to a tile roof. More specifically, the apparatus includes a base plate that is secured to the roof beneath various shapes of tiles on the tile roof and a generally L-shaped bracket that is then coupled to a rail support guide. The bracket is then capable of being adjusted in various locations along the base plate by utilizing a spring lock mechanism.

Abstract: The present invention is a turbo machine that is provided with an impeller that is rotated, and with a shaft that transmits rotation power to this impeller, wherein there is provided a differential screw having an impeller screw portion that is provided at one end thereof and that is screwed into the impeller, and having a shaft screw portion that is provided at another end thereof and that is screwed into the shaft, and that fastens the impeller and the shaft together, and wherein, in the differential screw, a thread diameter of thread ridges that are formed on the impeller screw portion is formed the same as a thread diameter of thread ridges that are formed on the shaft screw portion, and a screwing direction of the thread ridges that are formed on the impeller screw portion is formed as the same direction as a screwing direction of the thread ridges that are formed on the shaft screw portion, and a pitch between the thread ridges that are formed on the impeller screw portion is formed smaller than a pitch

Abstract: A securing member includes a flat base portion, a flat top board portion which is supported by a pair of top board supporting portions erected on the base portion, a long hole which penetrates through the top board portion and of which both ends are closed, a bolt having a head which does not pass through the long hole, and of which shaft is inserted through the long hole in a state where the head is located lower than the top board portion and is to be inserted through a supporting hole provided on a supporting member of a solar battery module, a head insertion hole through which the head of the bolt passes, penetrates through the top board portion, and communicates with the long hole, securing holes which are located on a line obtained by projecting a center line of the long hole, and penetrate through the base portion.

Abstract: A clamp (10) for holding two members together. The first member includes a recess into which a fastener is located. A bore is provided to the recess to allow a tool to be used to operate the fastener. The second member is arranged to accept the fastener and so join the members. The recess and bore are sized to prevent release of the fastener through the bore. In this way, the fastener cannot easily be removed or lost when the clamp is in use and is tamperproof. Embodiments of a downhole tool are described where the clamp is used to hold portions of a sleeve around a body of the tool, and to hold scraper blades and/or brushes to the body.

Abstract: A securing member includes a flat base portion, a flat top board portion which is supported by a pair of top board supporting portions erected on the base portion, a long hole which penetrates through the top board portion and of which both ends are closed, a bolt having a head which does not pass through the long hole, and of which shaft is inserted through the long hole in a state where the head is located lower than the top board portion and is to be inserted through a supporting hole provided on a supporting member of a solar battery module, a head insertion hole through which the head of the bolt passes, penetrates through the top board portion, and communicates with the long hole, securing holes which are located on a line obtained by projecting a center line of the long hole, and penetrate through the base portion.

Abstract: A connector for a container, particularly a cask, comprises a bush (14), intended to be received in an opening (11) in the container through which liquid is discharged, in use. The bush has a closed end (17) with a weakened portion (18), an inner thread (20) and an inner deformable portion (21). Sealing means (23) are intended to be disposed between the exterior of the bush and the interior of the opening at the position of the deformable portion. An insert (15) is screw-threadedly engageable within the bush so as to deform the deformable portion, thereby effecting compression, and thus sealing, of the sealing means between the bush and the container.

Abstract: Actuator stem and rod end bearings having locking mechanisms are described. An example apparatus for use with a control valve actuator includes a rod end bearing having a bearing retainer and a shaft portion extending from the bearing retainer. The apparatus also includes an actuator stem having a first end to be operatively coupled to a diaphragm plate of the control valve actuator and a second end to be coupled to the rod end bearing. A locking mechanism coupled to the actuator stem or the rod end bearing prevents the actuator stem and the rod end bearing from decoupling when the actuator stem is coupled or de-coupled to the diaphragm plate.

Abstract: A rigging for moving an aircraft panel relative to an aircraft substructure includes a retaining base attached to a panel interior, and a slider rod held in contact with the substructure and adjustably engaged with the retaining base. The slider rod is manipulable from the panel exterior to adjustably engage the panel in a rigging position along a fair axis. The slider rod may include a tool appurtenance captively positioned within the riser bore that is exteriorly manipulable through a panel access port. Tool appurtenance manipulation may actuate the slider rod to adjustably engage the support hub and to move the panel into the fair position. A fit plate may be attached to the aircraft panel disposed intermediate to the retaining base, and may be adjustably attached to the aircraft panel for moving the aircraft panel into a fit position in a rigging plane.

Abstract: A fabrication method for providing a relatively smooth surface associated with lightning strike protection for composite materials joined with fasteners recessed below the surface is described. The method includes coating at least one of a head of the fastener and a preformed dielectric insert with an adhesive, inserting the preformed dielectric insert into the recess such that the adhesive engages both contours of the recess and the preformed dielectric insert, and removing any excess adhesive from the surface area of the composite material and a top surface of the insert.

Abstract: A fastening device adapted in particular to be fastened on members having a grooved profile. The device has a main body, a control pin housed in engagement in this main body in an axial direction and moving with respect to this main body in order selectively to control the fastening or disengagement of this device, and a pressure member housed in the main body and moving with respect to the latter in a transverse direction. The pressure member is associated with the control pin such that, following the movement of the control pin with respect to the main body, the pressure member is moved in the transverse direction from and towards an operating position in which it projects from the main body.

Abstract: The present invention provides a fastening structure having two members that can prevent an axial force from decreasing due to thread loosening even at a temperature that is higher than that during tightening, and that always maintains a firmly fastened state. The fastening structure having two members comprises a first member that has a high thermal expansion rate is provided with an abutting portion on the distal end side of a threaded portion thereof, and a second member that has a low thermal expansion rate is provided with an abutted portion that is abutted by the abutting portion on the proximal end side of a thread-receiving portion. In such a fastening structure, as the temperature becomes higher, the threaded portion is more tightly clasped and compressed by the thread-receiving portion and the abutted portion. As a result, the fastening force between two members increases, and the axial force becomes large.

Abstract: Disclosed herein is a connection structure including, a first spherical member, a second spherical member, first and second clamping plates, a single external thread member, and first, second, third and forth clamping recessed portions.

Abstract: A connection system includes a float assembly and a locking assembly. The float assembly includes a floating ring and a float retainer disposed against the floating ring. The float retainer is adapted to be secured to a first object. The locking assembly includes a locking collar and a base retainer. The base retainer is coupled to the locking collar and adapted to be attached to a second object. The base retainer includes an engagement member engaging the floating ring, with the float retainer disposed between the floating ring and the locking assembly. The locking assembly is moveable between a first configuration wherein the float retainer is moveable relative to the locking assembly and a second configuration wherein the float retainer is fixed relative to the locking assembly.

Abstract: A clamp (10) for holding two members (12, 14) together. The first member includes a recess (30) into which a fastener (38) is located. A further access port (42) is provided to the recess to allow a tool (44) to be used to operate the fastener. The second member is arranged to accept the fastener and so join the members. The recess and port are sized to prevent release of the fastener through the port. In this way, the fastener cannot easily be removed or lost when the clamp is in use and is tamperproof. Embodiments of a downhole tool are described where the clamp is used to hold portions of a sleeve around a body of the tool, and to hold scraper blades (384) and/or brushes (394) to the body.

Abstract: A vehicle tie down rail conjoinment structure comprised of a first connector and a second connector each having a mounting surface at one extremity and an oblique slip-thrust surface formed at the opposite extremity. A threaded fastening component is utilized to conjoin the first connector and the second connector into a single physical entity, wherein the first connector is inserted into the inner diameter at the end section of the curved anchor footing of a vehicle tie down rail and the second coupling section is inserted into the inner diameter of the straight, thin long pipe member at the end section of the vehicle tie down rail.

Abstract: A ball socket for connection with a ball stud resists accidental pull-out of the ball stud. The ball socket includes arms that form a socket cup for retaining the ball stud. The arms allow relatively easy insertion of the stud head, yet greatly resist accidental pull-out. The ball socket may be used in connection with disengageable or conventional ball studs. The ball socket may be an in-line design, peanut-style, or some other design. One known effective application of the present invention is in automotive lamp assemblies. The in-line socket may include a centrally located mounting hole and an undercut which forms a chamber for trapping the head of a mounting screw to facilitate assembly to the reflector.

Abstract: A system for securing interlocking tubular components comprises first and second tubular. components to be secured and a locking apparatus located within the first tubular component. The first tubular component has a smaller diameter than the second component and contains slits that permit expansion of the outer diameter of the first tubular component under the action of the locking apparatus. Each of the first and second tubular components has an aperture therein, the locking apparatus having a spring-loaded button member that protrudes from the aperture of the first component. When the first component is inserted into the end of the second component,, the apertures are aligned and the button rises through the second aperture, thus holding the components together. An adjustment tool is then inserted through a bore in the button into the locking apparatus.

Abstract: A fastener system for joining structural members to other structural members or to supporting structures is disclosed. The fastener system includes three types of fasteners. The first type of fastener is designed for placement between adjacent planks. The second and third types of fastener are designed for placement at the ends or sides of planks which are not adjacent other planks. The first type of fastener is in the form of two rectangular, spaced apart plates which are fixed relative to one another by a rectangular plate extending perpendicularly between the two rectangular plates. The second and third types of fasteners are in the form of a rectangular plate having two rectangular, spaced apart plates projecting perpendicularly therefrom.

Abstract: A novel captivated jackscrew structure is characterized by the formation of both an internal cavity (15) within one of the two bodies that are to be connected together and an access passage (17). One end of the cavity, located at one end of the body is open. The small diameter access passage extends through the other end of the body into the cavity's other end. A standard machine screw (1) is installed head (3) first and captured within the cavity, with the screw shaft (5) protruding from the end of the body (20). A barrier (7) is provided to prevent withdrawal of the machine screw head, but permit the screw head and shaft to move a limited distance axially within the cavity. A backstop (9), resembling an inverted cup with a hole in the bottom lies in inverted position in the cavity over the screw's head.

Abstract: In accordance with the present invention, there is provided a low observable fastener for use with a panel structure having a panel bore formed therein. The panel structure has a RAM panel layer formed thereon. The RAM panel layer has a RAM panel layer bore formed therethrough aligned with the panel bore. The RAM panel layer bore defines an inner surface. The fastener is provided with a fastener head disposable within the panel bore. The fastener head has a tool engagement recess formed therein. The fastener is further provided with a RAM treatment layer disposed upon the fastener head. The RAM treatment layer has a fastener access bore aligned with the tool engagement recess of the fastener head. The RAM treatment layer further has a cylindrical outer surface sized and configured to be concentrically received by the inner surface of the RAM panel layer.

Abstract: A fastening assembly for fastening a first member to a second member comprising at least one threaded fastener having a head at one end thereof, the head having engagement surfaces for a tool, a threaded shank, the other end of the shank having engagement surfaces for a tool, at least one receiving bore in the first member into which the threaded shank is threaded in a pre-mounted state from one end thereof, with the head being spaced from the associated surface of the first member, the second member being preferably of thin sheet material and having at least one elongated opening, the opening having a first portion adapted to allow the entrance of head and a smaller portion adapted to accommodate the shank while the head grips behind the edge of the opening.

Abstract: A device (1) for holding two structural parts in a spaced relationship with respect to each other, having a spacer for filling the distance between the two structural parts, which spacer has a support part (2) which can be brought into a position fixed in rotation with respect to the second structural part (7) and a rotary drive part (3) which can be displaced axially with respect to the support part (2) by rotation. The support part (2) and rotary drive part (3) rest on a helical engagement surface (14, 17) which has a slope which is opposite the slope of a thread of a screw (11) which, upon being screwed into an axial opening (15) in the rotary drive part (3) carries the latter therealong.

Abstract: A coupling for parallelepiped-shaped or block-shaped mounting components for chucking workpieces in defined and reproducible positions, wherein the mounting components are provided with fitting bores and transverse bores having the same cross-sections and being arranged in regular coordinate intervals. The coupling includes a coupling member having a projection which can be inserted with precise fit into a hollow space provided at the end face of a mounting component to be connected. A plurality of hook elements are arranged in the projection, wherein the hook elements can be pivoted so as to produce a positively locking engagement with the wall surface of an adjacent fitting bore or transverse bore.

Abstract: A frame construction with several rod elements, which are connected at a node point by a node element (1) that has several holes (2.1, 2.3, . . . , 2.6) which are arranged on principal axes orthogonal to one another in pairs, distinguished in that a hole (2.2) is provided whose axis (s)--located in a plane defined by two principal axes (y, z)--is offset by preferably 15.degree., at most 20.5.degree., with respect to one of the two last-mentioned principal axes (y, z).

Abstract: A motor vehicle steering wheel including a hub, a longitudinal bore in the hub which receives a distal end of a steering shaft, a lateral bore in the hub which intersects the longitudinal bore, a cross bolt, and a plastic sleeve on a plastic shroud on the steering wheel which secures the cross bolt in a temporary position to the steering wheel. The plastic sleeve resiliently grips a screw-threaded barrel of the cross bolt and a pilot of the cross bolt partially obstructs the longitudinal bore in hub. The distal end of the steering shaft cams aside the pilot when the distal end is inserted in the longitudinal bore. The connection of the plastic sleeve to the shroud snaps the pilot of the cross bolt into a lateral notch in the distal end of the steering shaft to signal complete penetration of the distal end into the longitudinal bore in the hub.

Abstract: A connector structure for connecting together a plurality of elongated frame bars at their ends includes a main part having three side walls with mutually perpendicular quadrangular outer surfaces and a cover piece also having three side walls with mutually perpendicular outer surfaces such that they together assume a cubic form when they are attached to each other in a closed relationship with an engagement member on the inner surfaces of the three walls of the main part and a protrusion on the cover piece engaged to each other. Each side wall of the main part is provided with a throughhole for passing a screw through such that it can be attached to end surface of a frame bar. Such main part is produced by using only two mold pieces, an upper molding piece with a convex part and a lower molding piece with an indentation. The indentation has three inner surfaces, each making a same angle to the vertical direction.

Abstract: A fastening arrangement for connecting two items comprises a stud 16 secured to one item 14 and a captive fastener 18 located in a fastener body 20 secured to the other item. The captive fastener 18 is made up of a nut 32, a washer 34 and an outer clip 36 for securing the nut to the clip. The nut, washer and clip 36 may all be passed though the access opening 30 in the fastener body when separate, but when assembled, they resist withdrawal.

Abstract: A clamp-on aero bar for mounting on top portions of the handles of a road-type bicycle handlebar includes a pair of elongated curved hollow handle adapter portions and a pair of internally-adjustable clamping mechanisms. The internally-adjustable clamping mechanism are connected to the hollow handle adapter portions and are disposed substantially internally thereof such that a tool must first be extended through an opening in each of the handle adapter portions in order to reach and respectively tighten or untighten the internal clamping mechanism.

Abstract: Disclosed herein is an apparatus for providing a comfortable and esthetically pleasing seat in a whirlpool tub enclosure in which the seat doubles as a removable cover to allow access to the pump. The invention lies in the structure of the seat in which an indentation in the seat's side edge permits a bolt to be retained by a nut. The attachment can be secured below the surface of the seat to provide a comfortable sitting surface, while allowing access to the whirlpool mechanism when needed.

Abstract: A quick-connect fastener of a relatively-simple straightforward design is arranged with a tubular body adapted to be engaged against an attachment fitting in coincidental alignment with an opening in that fitting. A tubular collet having flexible fingers projecting from its forward end is arranged in the fastener body to be shifted forwardly by an elongated expander member coaxially arranged within the tubular collet for advancing the collet fingers into the opening in the attachment fitting. Biasing means are arranged between the elongated expander member and a rotatable actuator which is threadedly mounted within the tubular collet so as to be rotated for urging the expander member into engagement with the collet fingers.

Abstract: A part mounting device including a fixing metal member which is, in the inside of a synthetic-resin member, fixed to the other periphery of a metal member by the clamping force of a clamp screw. Inward protrusions are integrally formed on the synthetic-resin member, protruding radially inward. Engagement holes are formed in the fixing metal member for receiving the inward projections fitted into and engaged with the engagement holes. A bore is formed in the synthetic-resin member for inserting the clamp screw into the inside of the synthetic resin member.

Abstract: A captive ball and socket joint where the socket is made from bearing material which is encased in a metal shell, thereby forming a socket around the ball head on the end of a ball stud. The metal shell is cup-shaped and has its base wall apertured so that the ball formed with internal wrenching socket is accessible through the aperture when the ball and the bearing socket are placed into the cup-shaped shell. A flat steel connector lug is pierced with an opening and the wall of the metal cup-shaped shell is secured within the opening by welding. The edge portion of the shell is deformed to render the ball and socket captive in assembly with the lug. The hole in the base wall of the shell permits access for insertion of a rotary drive tool to engage a formation in the ball component to rotate the ball component and secure it to a machine element such as a brace or bracket. The bearing socket can be one or two pieces and can be made from metal bearing material or a plastic bearing material.

Abstract: A ball joint comprises companion inner and outer hollow ball sections each comprising a major segment of a sphere. Spring means within the ball sections urges a friction pad into engagement with the interior surface of one of the sections. Screws within the ball sections adjusts the spring force, the screws being accessible for movement through a series of openings in one of the ball sections.

Abstract: A locking screw is disclosed having a shank and a frustoconical head with a cavity therein and a knurled annular end surface portion encircling the cavity. The locking screw is disposed within the arm of a joint connecting member which arm is inserted in a tubular structural member. The screw is turned out from the arm into engagement with the structural member holding the joint and structural member securely together.

Abstract: A joint for a knock-down furniture assembly including a rod which has a slip fitting engagement with a bushing. The rod is affixed to one component of the furniture and the bushing to another component. In one embodiment, the rod has a head which fits within a hole in a first wood component and is captured by means of cured epoxy resin introduced into the hole or on an immediate adjacent portion of the rod shank. Set screws are threaded into tapped holes in the side wall of the bushing and are accessible through aligned holes in the second wood component for actuation by polygonally shaped wrench engaging similarly shaped sockets in the ends of the set screws for tightening against the inserted rod shank thereby to lock the two components in assembly and for loosening to unlock them. In another embodiment, the rod is an octagonal rod which slip fits into a square tube. The octagonal rod includes a transverse threaded bore into which a set screw is inserted.

Abstract: A blade positioner for a scroll saw is disclosed which permits adjustment of the saw blade relative to the pivoting beams or arms of the scroll saw so that the plane movement of the blade is coincident with the blade direction, particularly in the event that the ends of the arms are somewhat misaligned with respect to the plane of travel of the arms due to inaccuracies of the arm pivot bearing locations. Also disclosed is an anti-rattle spring interposed between the work table and work table support so as to minimize rattle of the work table relative to the support in all directions.

Abstract: A support for a rolling bearing is provided with an essentially annular transition region between sleeve-shaped portion and a flange connected thereto, the flange having a plurality of circumferentially distributed, axially extending mounting holes. The transition region has a concavely curved or linearly inclined profile. A substantially spherical base surface is provided axially of each mounting hole, the base surface connecting the rim of the hole with the inner surface of a substantially part-cylindrical recess in the transition region, the recess having a diameter greater than the hole diameter.

Abstract: A picker spindle assembly for cotton pickers includes a plurality of vertically extending picker bars each mounted to a pedestal flange via a bar pivot, each bar pivot carrying a plurality of horizontally extending spindle pickers. Each of the bar pivots is threadedly mounted to a mounting plate secured to the pedestal flange to permit vertical adjustment of the spindle pickers.

Abstract: This invention relates to an improved structure for tee joint comprising a first tube provided at one end with a saddle shaped recess. A second tube is furnished at its periphery with a pair of aligned holes and can be disposed on the recess of the first tube. A housing provided at its center with tapered recess is received in and secured to the interior of the first tube near the recess thereof. A tapered plug is received in and secured to the tapered recess of the housing. A threaded member is passed through the aligned holes of the second tube and engaged with the tapered plug received in the first tube to make the second tube fixedly secured to the first tube.

Abstract: A clamping device with an improved attachment of a component (3) inserted in a hole (2) has a casing (5) of a deformable material arranged in a recess (4) in the end of the component and a V-shaped notch open towards the end of the component, a wedge (10) inserted in the notch with its longitudinal direction parallel to the end surface of the component, a screw (12) engaging in a threaded hole (11) through the wedge and extending through a hole (13) through the casing, the wedge being pressed down into the notch of the casing by the screw thereby displacing parts of the casing located around the notch towards parts of the component located on both sides of the recess (4) so that the latter parts are pressed towards the wall of the hole at right angles to the longitudinal direction of the wedge.

Abstract: In order to obtain a high initial stress force of the screw, in particular cap screw, in a framework made of hollow sections used as bar elements, joined at separate junction members, having connecting parts for the bar elements, whereby threaded holes are provided at the exposed ends of the connecting parts and plates with central bores are provided at the end of the bar elements, on each of the plates a cap screw with its head positioned within the bar element being inserted and screwable into the threaded bore on the side of the connecting part, whereby finally the bar elements, the plates and the connecting parts reach a smooth exterior profiling, achieving a framework free of recesses and projections it is proposed that a tubular guiding piece (6) be supported by the plate (4) inside the bar element (2) forming a sliding duct for the cap screw (7) and running slightly curved with respect to the wall of the corresponding bar element (2) and abutting in an opening (8) for the passage of the screw provided

Abstract: Sections of hollow tubular pipe are joined together by one or more differentially threaded, axially mounted screw which threadedly engages internal radial flanges at the end portions of the adjacent pipes, an extension socket rotates the internal screw or screws.

Abstract: A hub for a clutch having a bore and an apparatus for connecting the bore of the hub to a shaft end having a threaded axial hole and disconnecting the hub from the shaft, the improvement in the apparatus for connection and disconnection of the hub from the shaft including the hub having a stop shoulder formed in the bore and a bolt having a recess in the head thereof together with a mounting washer positioned against the stop shoulder. A bolt is positioned through the washer with the head of the bolt in rotational contact with the mounting washer. A containment ring is secured to the mounting washer to prevent displacement of the bolt head from the mounting washer. A bolt containment ring is secured in the bore of the hub adjacent the containment ring to prevent displacement of the bolt, mounting washer and containment ring from the bore whereby the bolt may be engaged with the threaded hole of the shaft to thereby removeably mount the hub on the shaft end.

Abstract: A tubing connector for connecting lengths of round or square tubing includes a base block with an integrally molded connecting arm. Additional connecting arms are connected to the base block by screws which extend through a hollow bore in the connecting arm and an aperture in an end face of the connecting arm. The screws are threadably received in the base block.

Abstract: A fixing device for fixing a handle stem to a front fork at a bicycle. A screw thread is provided at the inner periphery of the hollow handle, with which is screwed a handle expander bolt having a rotary control and carrying an expander cone, so that the expander bolt is screwed forward and backward with the thread, thereby moving the expander cone with respect to the handle stem.

Abstract: A fastening arrangement for a bumper, especially for a bumper drawn down relatively far on the end of the body at the subframe of a motor vehicle, in which the bumper part to be fastened to the subframe is supported at a cross bearer connecting two vehicle longitudinal bearers with each other. Free ends of the bumper project into the associated longitudinal bearers; each of the free ends being also supported at the frame connection formed by the cross and longitudinal bearers.

Abstract: A connector for an elongate member in frame structures such as seating, scaffolding and the like, in which an elongate member is removably secured to another member to extend therefrom in selected angular relation. The connector includes a lug on one member and extending therefrom and shaped to be received inside of a tubular end of a second member with the lug and a partition in the second member having facing surfaces at an angle to a line on which the second member extends from the first member with fastening means drawing the partition toward the lug to clamp the adjacent end of the second member to the first member, the tubular portion of the second member having an opening adjacent the fastening member for access thereto, the engagement of the second member with the lug and first member and the relation of the partition to the lug cooperating to orient and fix the second member relative to the first member.

Abstract: Tubular frame structures such as for furniture, cabinets, display stands or the like comprise square tubular metal elements held together by a series of right angle connector structures. The improved connector comprises a channel having one end fixedly attached to a first frame element. A second frame element telescopes over the channel. A jack screw, accessible through a hole in the second frame element, engages a bowed toggle spring to force the sides of the channel apart. Engagement is established at two corners at the ends of one side of the frame while the reaction is sustained by the base of the channel.