Abstract: A modular truss system (30) is disclosed that is especially suited for support of lighting, cameras and the like in association with a stage for performances thereon. The truss system includes cups (80) and alignment members (82) that aid in aligning the truss modules (62) for assembly thereof. The system also includes box shaped braces (78) to achieve longitudinal and transverse strength.

Abstract: In the case of a shaft coupling for bottom cylinders of drafting units on spinning machines, a shaft is provided on its end with an area of a reduced diameter which engages in a longitudinal bore at the end of the other shaft. In the area of the longitudinal bore, the two shafts are connected with one another by means of a screw thread. In addition to the screw thread, the area of the reduced diameter also comprises two centering surfaces with fits, one fit being a clearance fit and the other fit being a press fit. As a result, radial deviations of the shafts caused by the shaft coupling are to be avoided.

Abstract: An interior sleeve for a pair of telescoping tubular members, in which the sleeve is mounted in an outer tubular member. The sleeve has locking studs on its exterior surface which are aligned with locking apertures in the outer tubular member. The sleeve has an annular flange disposed on the outer end of the sleeve to abut to the outer end of the outer tubular member and a longitudinal slot to allow compression of the sleeve to fit into the tubular member.

Abstract: An oral hygiene device has a handle and an automatic stem insertion system and comprises a pair of keys on the motor driven shaft. A bore receives the shaft, and slots receive the keys. A pair of sleeves each having a ramp for receiving and engaging the keys. When coupling the stem to the handle and with a camming action of the keys on the ramp, the ramps guide the keys into the slots. A radially extending flange is on the base of the shaft; and a pair of flexible arms having a recess receive the flange. Upon coupling the stem to the handle, the flange engages the arms and flex the arms outwardly and further movement of the stem onto the handle causes the flange to enter the recesses with a snap action; and upon withdrawal of the stem from the handle, the flange causes the arm to flex outwardly to release the flanges from the recesses.

Abstract: A multi-piece tool bar assembly including a main support structure suited for connection to a frame of an agricultural implement and a second support structure selectively attachable in end-to-end abutting relation with the main support structure for extending the effective length of the tool bar assembly. A fastener assembly initially aligns support surfaces on the support structures relative to each other and thereafter maintains such alignment to facilitate movement of one or more row units onto the second support structure. The fastener assembly is arranged wholly within the exterior of the support structures and comprises a guide pin which extends beyond an abutting end of one of the support structures and is accommodated in a close sliding fit relationship within an opening defined at the abutting end of the other support structure. The guide pin and opening are precisely located on the respective support structures to ensure alignment of the support surfaces of the support structures.

Abstract: An article of manufacture is disclosed having a first part constructed or powdered metal and having a lip which extends outwardly from one end of the first part. A second part, for example a steel stamping, has a first side, a second side and an opening extending between its sides. The opening is dimensioned so that, with the second part positioned on the end of the first part, the lip extends through the opening and outwardly from the second or outer side of the second part. The first and second parts are then mechanically secured together by deforming the lip so that a portion of lip overlies and entraps an edge portion of the second part between the deformed lip and the end of the first part.

Abstract: A structure for mounting an air bag in an air bag system, comprises a retainer having an inflator mounting opening, an air bag having an inflator receiving opening aligned with the inflator mounting opening, a press ring cooperating with the retainer to sandwich the peripheral edge of the inflator receiving opening of the air bag, and means for securing the press ring to the retainer. The structure further includes a sheet made of synthetic resin and attached to the peripheral edge of the inflator receiving opening of the air bag.

Abstract: A device for fastening an article, disposed at an end of a cylindrical shaft, portion, to one coupling member of a coupling means whose other coupling member is anchored at a machine tool, especially a die sinking electric discharge machine. One coupling member includes a bore to receive the shaft portion. An intermediate piece consisting of a shaft portion and a fixing portion is made in one-piece, preferably by an aluminum casting process. The fixing portion is adapted for engagement with an interlocking means disposed at the wall of a take-up sleeve of the coupling member. Likewise provided is a one-piece bushing to take up a shank of an article the outer surface of the bushing at least in part being in engagement with the inner surface of the hollow end remote from the coupling member of the cylindrical shaft.

Abstract: A slope and skew hanger for connecting a rafter to a beam at a variety of slope and skew angles. The hanger includes a connection portion and an integrally attached seat portion which is connected with the connection portion along a bend line. The connection portion includes a central opening, a pair of side connecting brackets joined by connecting strips and adapted for connection to the beam, and a pair of centrally positioned connection flanges extending outwardly from the front face of the connection portion and adapted for connection with the sides of the rafter. A further feature of the present invention is the provision of a raised spherical portion and an offset nail receiving opening to facilitate the angled nailing of such a hanger or bracket to the beam or rafter.

Abstract: Method and apparatus for joining structures, an active structure (10) and a passive structure (12), and imposing a tensile pre-load on the joint by a remotely operable mechanism comprising a heat contractible joining element (15). The method and apparatus include mounting on the structure (10) a probe shaft (15) of material which is transformable from an expanded length to a contracted length when heated to a specific temperature range. The shaft (15) is provided with a probe head (21) which is receivable in a receptacle opening (41) formed in the passive structure (12) when the active structure (10) is moved into engagement therewith by an appropriate manipulator mechanism. A latching system (45) mounted on the structure (12) adjacent to the receptacle opening (41) captures the probe head (21) when the probe head (21) is inserted a predetermined amount.

Abstract: A first tube of rectangular cross section is joined to a second tube by notching the first tube on two sides to assure that the top and bottom walls of the first tube touch the rounded corner of the second tube at a central location to define a weld receiving groove and to eliminate the gap between the abutted tubes for repeatable, well defined welds. To avoid large fixtures and structural locators adjacent a weld location, a small tab is provided in the notched end of the first tube. An oversized laser-cut slot in the side of the second tube receives the tab and has one slot boundary precisely located with respect to a reference point on the second tube. The first tube is urged in the direction to force the tab against the boundary and positively locate the first tube with respect to the reference point.

Abstract: A connector sleeve device for connecting together first and second posts, comprises a sleeve having an outer surface dimensioned to be received within the interior surfaces of the first and second posts. A first flexible protrusion is formed in a mid-region of the sleeve and has an abutment surface adapted to abut an end surface of the first post when the sleeve is received therein. The contact between the abutment surface and the end surface prevents the sleeve from being moved further into the second post. A second flexible protrusion is formed in the mid-region of the sleeve and has a second abutment surface adapted to abut an end surface of the second post when the sleeve is inserted into the second post. The contact between the second abutment surface and end surface of the second post prevents the sleeve from being moved further into the second post.

Abstract: A coupler body 12 with a socket 44 therein is attached to nuclear stream generator tools to be mated with an arm 22 of a remotely controlled manipulator. A plug 16 for insertion in socket 44 is mounted with a ball detent lock actuating air cylinder 18 on L-shaped bracket 20 attached to the end of arm 22. Cam surfaces 62 on body 12 and 64 on bracket 20 align the plug 16 and socket 44 for insertion to mate and couple the tools and arm 22.

Abstract: An improved drum brake includes a brake drum rotating along with a wheel, a backing plate provided to a stationary portion of a vehicle, a pair of brake shoes that are movably supported on the backing plate and a wheel cylinder attached to the backing plate. The wheel cylinder is adapted to expand the brake shoes to an operating position whereby friction linings attached to the brake shoes are frictionally engaged with an inner peripheral surface of the brake drum. An adjustable strut is disposed between the brake shoes to maintain the spacing therebetween and a return spring is provided adjacent the strut for retracting the brake shoes away from the inner peripheral surface of the brake drum. An end portion of the strut is provided with a bend portion parallel to a web of one of the brake shoes, the bend portion being sandwiched between the web of the brake shoe and an end of the return spring.

Abstract: A dowel fastening support device for insertion into a bored hole of a structural element having a support member outside the bored opening and an elongated shank having pivotable triangular-shaped gripping members for insertion in said bored hole, said gripping members being so configured that the forward edge of each member is spaced from the adjacent interior surface of said bored hole, and the device is provided with a pointed element at the end of the shank remote from the support end portion for automatically centering the dowel device, when the latter is inserted in said bored opening.

Abstract: A self-aligning connecting system for connecting structural sections (10), the system having at least one pair of connector halves (20), each pair (20) comprising a male half (30) attached at one end of a truss section (10b) and a female half (70) attached at an opposing end of an adjoining truss section (10a). Male half (30) comprises a floating peg (42) within slot (39) which engages a bore (79) located on female half (70). Opposing ends of two truss sections (10a & 10b) are then joined together by inserting the peg (42) of each male half (30) into the corresponding bore (79) of each female half (70). Lock pin (97) then engages each peg (42) in chamber (50) to connect the truss sections. Truss sections (10a & 10b) are thereafter quickly and easily disassembled and reassembled by simply removing and replacing each lock pin (97).

Abstract: A device for securing a mechanical drive component to a drive shaft comprises a hub having an extended slotted member and a hub member. The hub member has a knurled surface for securing the hub to the drive component by pressed fit. A clamping collar is used for clamping the slotted member to the drive shaft. The slotted member of the hub includes a rib for aligning the slots in the slotted member relative to a split in the collar.

Abstract: A connecting rod assembly comprising a connecting rod having a rod lug, a connecting rod cap having a cap lug with the rod lug having a straight bore therein which coaxially aligns with a straight bore in said cap lug when the cap lug engages the rod lug. The connecting rod assembly further includes a bolt comprising a shank having an enlarged portion and a pilot portion. The enlarged portion has a cross section larger than each of the bores prior to insertion therein. The enlarged portion also has a tapered part, and is constructed of a sufficiently deformable material to enable insertion of said enlarged portion into each of the bores and fricitional retainment of the enlarged portion therein. The enlarged portion has a length sized so that it extends through a sufficient axial portion of each of the bores to hold the rod and cap lugs in abutting relation wherein the tapered part constitutes the entire part of the enlarged portion extending into one of the bores.

Abstract: A connector sleeve device for connecting together first and second posts comprises a sleeve having an outer surface dimensioned to be received within the interior surfaces of the first and second posts. A first flexible protrusion is formed in a mid-region of the sleeve and has an abutment surface adapted to abut an end surface of the first post when the sleeve is received therein. The contact between the abutment surface and the end surface prevents the sleeve from being moved further into the first post. A second flexible protrusion is formed in the mid-region of the sleeve and has a second abutment surface adapted to abut an end surface of the second post when the sleeve is inserted into the second post. The contact between the second abutment surface and the end surface of the second post prevents the sleeve from being moved further into the second post.

Abstract: An auxiliary equipment attachment adapter, to be used in pairs, semipermanently attaches to the customary mounting fixtures on a vehicle for commonly available equipment including snow plows. The adapter has open horizontally diverging jaws, upwardly inclined to direct the attachment plate of the equipment to be attached into a retaining slot of the adapter. The equipment is modified by having a retaining bar placed between its attachments plates to engage a latch that holds the attachments plates in their retaining slots. The rearward portion of the adapter is an I-beam that rigidly encompasses the mounting fixtures of the vehicle and is pinned thereto through the web of the I-beam. This adapter and method provides a safe and easy method for engaging and disengaging attachments by one person from within the cab of any vehicle with no manual positioning of the attachment from outside the vehicle.

Abstract: A mounting/dismounting system for mounting and dismounting a spray gun carried on an adapter on and from an arm of a robot comprises a base extending horizontally and having a flat top surface defined by a first side facing the robot and a second side opposing the first side for supporting the adapter when the spray gun is placed on the base. The flat top surface is further defined with a predetermined position on which the adapter is to be held when the spray gun carried by the adapter is waiting for mounting on the arm of the robot.

Abstract: A rotatable coupling having a male member (2) and a female member (4) each rotatable about central axes .alpha. and .beta.. The male member has lobes (16) and the female member cavities (50) for mutual engagement. The male lobes terminate in wedge-shaped portions (18), the edges of which lie in a common plane. The female terminates in a flat bottom surface (40).

Abstract: Apparatus for insertion of an object into a close clearance hole utilizing a double taper starter system. The apparatus includes a first taper to align the object radially; a narrow section of length such that with the object tilted to the angle of the first taper, clearance in the hole is maintained; a cut-back segment of either constant diameter or reverse taper geometry; and a second taper of approximately the same size and shape as the first taper to align the object angularly. The apparatus of the invention can be advantageously used in mechanized assembly processes, the assembly of shafts into bearings, and in thermally assembled or regular interference fits.

Abstract: The device comprises an integrated unit formed by a container element having an opening for the filler, a door hinged onto the container element and subject to the action of an opening spring and an electrically actuatable lock for the door. The container element with the door and the lock mounted thereon are fastened as a single unit to the metal sheet of the bodywork.

Abstract: A device for the correct positioning of the lower steering shaft on the steering-box pinion and on the upper steering shaft respectively comprises a bush with a reference tooth which, as well as ensuring the correct positioning of the clamping screw, also simultaneously ensures the secure clamping of the screw for the correct connection of the aforementioned members. The reference tooth on the bush may be replaced by a bracket welded to the fork of the universal joint of the lower steering shaft.

Abstract: A connecting mechanism is formed by providing grooves having angularly disposed slopes in a rotary member in a position facing the outside of guide grooves provided in a housing for engaging endoscope fitting pins and providing an energizing device biasing the rotary member for rotation in one direction so that the endoscope may be locked and fitted by the simple operation of pushing in the endoscope forward through an open end of the housing.

Abstract: A quick connect-disconnect coupling for joining two drive shafts on a common axis for simultaneous movement where one drive shaft extends from a prime mover and the other from a piece of equipment. The coupling includes a first mating member mounted on one of the drive shafts that has socket means and drive pin means, and a second mating member on the other of said drive shafts that has a ball member matable with said socket and pin engaging means to receive said pins which when said pins are rotated will impart rotation to the first mating member for simultaneous rotation.

Abstract: A coupler assembly having male and female coupler members, the female coupler member having at least one linear open ended slot therein adapted to receive a drive pin on the male coupler member, the female coupler member also having an annular opening angularly displaced with respect to the linear slot, the male coupler member also having a depressible locking pin adapted to be depressed by the female coupler member as the drive pin is inserted into the linear slot, the locking pin being positioned to enter the annular opening in the female coupler member when the projection reaches the inner end of the slot, thereby locking together the coupler members.

Abstract: Conventionally, substantially rigid parts such as panels and the like, are joined by mechanical fitments or couplers which not only require tools to assemble and disassemble but also create concentrated stress points at the junctions where the fitments or couplers are located. The present device utilizes hook and loop coupling material to detachably secure the parts together and incorporate mechanical location and aligning means between the two parts just prior to the engagement of the hook and loop fastener portions with one another thus facilitating the accurate assembly of the parts. Although designed primarily for use in various types of knock-down furniture and the like, it can of course be adapted for use with other substantially rigid parts.

Abstract: A locking system is described for detachably securing two workpieces together (e.g., two housing sections). Elongated arms are carried by one workpiece and a corresponding opening(s) is present in the other workpiece. The outer end of each elongated arm is resiliently deflectable so that it is deflected when being inserted into the opening in the one workpiece; then the arm springs back. A locking arm on the second workpiece is then able to move behind the end of the elongated arm to restrict deflection of the arm, thus preventing any unintentional unlocking of the two workpieces.

Abstract: A main frame of a passenger conveyor has a plurality of frame sections divided along the length thereof. Each adjacent pair of frame sections have opposed joint members provided at joint portions of the frame sections. When the frame sections are provisionally assembled, one of the joint members is formed therein with a positioning hole whereas the other joint member is fixedly connected with a positioning pin which, when the frame sections are re-assembled at an installation site, is engaged with the positioning hole to facilitate easy and quick re-assembly of the frame sections.

Abstract: A three-stage system movable in three orthogonal directions includes a pair of cam rods and a screw insertion device secured to one of the stages for displacement in three orthogonal directions. A cabinet has a screw receiving aperture pedestal with aperture locating cam surfaces in a given orientation and spacing. The cam rods are in the same orientation and spacing as the cam surfaces and when engaged align the screw insertion device with the screw aperture. After alignment, a screwdriver attached to the three-stage system drives the screw into the aperture. An automatic feed system feeds screws to the insertion device. A plurality of such three-stage systems are used for automatically attaching an apparatus to the cabinet.

Abstract: A fastener assembly adapted for use in connection with a first and second apertured workpiece, said fastener assembly comprising a fastener, washer and rubber grommet, said fastener having a head, and a shank; said shank including an upper shank portion, a lower threaded shank portion and a pair of wings spaced between said upper unthreaded shank portion and lower threaded shank portion; said washer and rubber grommet being telescopically associated with said fastener.

Abstract: The coupling piece for connecting two container corner fittings has a housing (10) with an upper and a lower middle piece (21/22), a locking bolt (15) and two crossbars (16 and 17) fastened to its free ends projecting from the housing (10). The lower middle piece (22) only partially matches the contour of an orifice in a container corner fitting, so that the lower crossbar (17) projects laterally beyond it. In the released position, the upper and lower crossbars (16 and 17) are rotated through an angle relative to one another, so that the lower crossbar (17) has to be introduced into the container corner fitting first and then the entire housing has to be rotated through this angle, before the upper crossbar (16) is correctly aligned opposite the orifice in the container corner fitting of the upper container.

Abstract: A bearing assembly comprising inner and outer rings provided with cooperating axially outwardly and inwardly facing bearing races in which the ring having axially inwardly facing races is split into two portions which are secured to one another to retain bearing races and which are radially and circumferentially positioned and secured to one another. A method of forming a precision bearing assembly as described.

Abstract: A carrying device for a storage battery is disclosed. In one embodiment, the carrying device comprises two retractable handles attached to the storage battery and guidance members associated with said handles for guiding the movement of the handles. Each of the handles has a crosspiece and arms extending along the sides of the storage battery. The arms contain elongated slits which receive the guidance members and thereby ensure accurate guidance of the handles.

Abstract: An attachment for a snow plow having a normally vertically-oriented snow plow blade. The attachment is composed of a side plate which is installed at an end of the blade. A brace is installed between the blade and the side plate for preventing lateral displacement of the plate, and the plate is immobily secured in place and aligned with the plow blade to assure proper orientation during use.

Abstract: A mounting bracket, especially suitable for supporting a green tire holder, comprises, in series, a fixed bracket secured to a tire mold press, a hollow rectangular housing, and an adjustable arm for supporting a green tire holder on a vertical shaft. The adjustable arm is axially movable, and is also horizontally, vertically, and rotatably adjustable with respect to the hollow housing, so that the shaft can be precisely positioned with respect to the axis of the tire mold. The hollow rectangular housing is secured to the fixed bracket by means of a pivot screw and a removable pin. The housing is fixedly secured to the fixed bracket when the removable pin is in place, and is capable of being swung, so as to permit access to the tire mold, when the pin is removed.

Abstract: In the case of a plug connection for drilling or boring tubes, rods and worms for earth boring equipment with a male part and a female part, with a radial coupling for torque transfer and with an axial coupling having in the overlap zone of the male and female parts a locking device which can be introduced into an annulus for transferring axial forces, it is provided that the locking device is constructed as a multilink chain, which essentially extends around the entire annulus and which is introduced through the female part into the annulus via a single opening. This device provides a plug connection, which has a very simple construction and after extremely rapid installation is suitable for transferring very high forces.

Abstract: A joint for reinforcing bars includes a joint main body having a pair of substantially parallel side walls and at least one curved wall which connects together the end edges of both side walls, together and a wedge inserted into wedge bores which are respectively provided in the side walls in such a manner so as to be aligned with each other. The end portion of each of the reinforcing bars which are to be connected together are set in such a manner so as to contact the inside of the curved wall, and the wedge is press-fitted into the wedge bores. Thus the end portion of each reinforcing bar is clamped and thereby rigidly secured between the wedge and the curved wall. The curved portion is formed so as to have a substantially V-shaped inner wall surface including a pair of slanting surfaces. Thus, the end portion of each of the reinforcing bars which is pressed by the wedge is pressed against the pair of slanting surfaces and allowed to bite into the area defined therebetween.

Abstract: Coupling of two flanged shafts end-to-end by means of taper pin bolts and expansion sleeves cooperating with the pin bolts and having the same conicity, said sleeves extending into bores provided in said flanges and said pin bolts having external threads on both ends, a first end being located on the small side of the taper cone and a second end on the large side of the cone, is accomplished by:(a) inserting each pin bolt together with its sleeve into the corresponding bores,(b) screwing a nut onto the first end of the pin,(c) exerting a tractive force on the second end by means of a cylinder, the nut of the first end bearing against the corresponding flange,(d) while maintaining the tractive force on the second end, applying a nut against the second corresponding flange by screwing the nut up on the second end of the pin bolt,(e) and pushing back the sleeve toward said second end and cancelling the action of the cylinder.

Abstract: A coupling device for connecting a work tool to a support that provides a quick disconnect for electrical and fluid connections and is characterized by the use of two separable members which can be locked together through a ball cage and lock ring arrangement.

Abstract: A connector has juxtaposed modular blocks bearing either sockets or pins. The modules are removably mounted, side-by-side, in adjoining recesses of a generally flat, rectangular housing. The adjoining recesses are provided with a number of notches which are initially closed off during manfacturing. The insertable modules are provided with one or more protruding tabs which cooperatively fit into the corresponding notches in the housing, provided that the notches have been selectively opened in order to receive the tabs of the particular module. Furthermore, the mating connector portions may similarly be provided with corresponding tabs and notches, the latter being initially closed during manufacture and later selectively opened to receive a particular connector having certain tabs thereon.

Abstract: A connecting fitting for detachable connection of furniture parts is provided with a spring mounted tongue on one fitting part engageable behind a protrusion on another fitting part and with the tongue being movable by an eccentric bolt with a protruding cam engageable with a protrusion on the tongue to disengage the tongue from the protrusion.

Abstract: A tube coupler consisting of a tube piece cut longitudinally and provided internally with two pairs of double-acting hydraulic cylinder-piston units hinged to the wall of the tube piece and each acting on two connecting rods which are hinged to said wall on opposite sides of the longitudinal cut. The tube piece is also provided with two sets of longitudinal spacer members on its outer surface and with frusto-conical endpieces at its extremities.

Abstract: A positioning member is installed on a pinion of a steering gear in such a manner that its U-shaped bend forms an alignment mark. A yoke of a steering shaft joint has a slit which forms an alignment mark. The U-shaped bend is insertable into the slit only when the pinion and the steering shaft are properly aligned.

Abstract: A bolt type, split ring clench clamp as used to apply a clamp-up force to the slotted end of a turnbuckle has an orientation washer supported by the clench bolt between the terminal lugs of the clamp so that one end portion of the orientation washer loosely extends into the slot whereby to effect radial orientation of the clamp relative to the slot, the orientation washer also including means to abut either against the end of the turnbuckle or the blind end of the slot whereby to effect longitudinal orientation of the clamp on the turnbuckle so that a desired clamp-up force can be applied to the slotted end of the turnbuckle.

Abstract: An aeroplane propeller assembly comprising a pair of hub members made of nylon with glass fibers interspersed therein forming an undulant gripping surface for clamping the root ends of wooden propeller blades and embedding the raised areas of the hub surfaces into the wood to obtain a firm and shakeproof purchase thereon as the hub members are bolted to each other and to the blades. The hub members are in the form of discs and have root-end-confining pockets formed to clamp the end portions and hold them under compression tightly within the pockets, each pocket having sharp pins molded therein and strategically located not only to pierce into the wood but also to swell the wood and contour it against the enclosing surfaces of the pocket. The propeller blade root ends are adapted to be cut at different angles to obtain different pitch upon being fitted into the same pockets.

Abstract: A cross country ski binding (10) includes a base plate (16), a pivot plate (18) hinged to the base plate, an upstanding transverse lug (36) on the pivot plate for receiving a slotted toe plate (38) on the ski boot, and a wire clamp (54) for releasbly securing the toe plate and ski boot to the pivot plate. A vertical tongue-and-slot arrangement together with abutting engagement between the pivot plate (18) and toe plate (38), in combination with the releasable wire clamp (54), provide a more positive connection while at the same time allowing free pivotal movement of the boot relative to the ski. In a second embodiment, the ski binding (70) includes a horizontal tongue-and-slot arrangement (74, 76 and 78) together with a latch (84) resiliently urged into engagement with a slot (86) in the toe plate (38').

Abstract: The invention relates to a coupling for making a connection secured against relative rotational and axial displacement between a hub member and a shaft member. The shaft and hub members have engaging keys and grooves at the internal and external circumferences thereof. The hub member has a circumferential groove undercutting the keys thereof and an insert member having the same key and groove configuration as the shaft member is disposed therein. The insert member is circumferentially offset relative to the hub member so that the respective keys and grooves thereof are out of alignment. The keys of the insert and hub members are then in axially abutting engagement with the insert member serving as an anchor so that a screw connection between the shaft and the insert members allows the shaft and hub members to be drawn towards each other to form a firm and secure connection.