Abstract: A gripping assembly for a robot includes a body and a pair of jaw supports supported for slidable movement on the body toward and away from each. Each jaw support has a pair of spaced apart apertures for receiving spaced apart securing posts of a jaw. Each jaw support includes a support body and a pair of locking slides. Each locking slide has a first end configured to engage a securing post when the securing post is disposed in a corresponding aperture. At least one actuator is configured to drive the locking slides away from each other to engage the securing posts. A jaw support actuator is configured to drive the jaw supports toward and away from each other.

Abstract: A chuck-claw coupling mechanism includes a coupling member provided in a master jaw, a first resilient member, and an operation unit. The coupling member is movable between a coupling position at which the coupling member is coupled to the claw, and a separation position at which the coupling member is separated from the claw. The first resilient member urges the coupling member toward the coupling position. The operation unit moves the coupling member to the separation position.

Abstract: A workholding apparatus comprising a chuck body, first jaw members and second jaw members wherein the second jaw members are shaped to grip a workpiece of a particular geometry. The first and second jaw members are constructed to enable easy, quick and manual replacement of the second jaw members with other second jaw members having different grip shapes so as to enable gripping of workpieces with different geometries.

Abstract: A system, in certain embodiments, includes a wedge-lock coupling configured to connect a jaw to an actuator arm of a chuck. The wedge-lock coupling includes a wedge portion having a path of travel between a release position and a lock position, and a locking direction along the path of travel gradually wedges the wedge portion between the actuator arm and the jaw.

Abstract: A diaphragm chuck with an operating element inserted in a chuck body and axially movable in relation to the chuck body, a diaphragm attached to a free end of the operating element with the diaphragm secured to the chuck body by its outer circumference, three base jaws in driving connection with the diaphragm, on each of which a centering surface is disposed in a concentric alignment with the axis of the operating element, three clamping jaws attached to the corresponding base jaws, by which a gear to be machined can be clamped and which make contact with the centering surface, and clamping pins, each allocated to one of the clamping jaws, radially aligned and arranged between two teeth of the gear in the clamped condition, such that the diaphragm chucks reliably clamps differently sized gears and gears with different numbers of teeth between the three clamping jaws.

Abstract: A chuck-related arrangement having a main portion and chuck jaw portions coordinated with the main portion with associated clamping arrangements, wherein one surface of the main portion is provided with a plurality of tracks adapted to displaceably carry chuck jaw portions. Each one of, and/or a chosen number of, clamping arrangements, are individually to be secured to its element solidly secured to its basic chuck jaw portion exposing a rotational cooperation with an external chuck jaw portion over a central axis of rotation. Two or more of the external chuck jaw portions and their peripheral surfaces are formed as one or more recesses in order to cooperate opposed recesses to form clamping surfaces for a work piece and/or formed as one or more, the recesses intermediately oriented, radially extending elevations, causing cooperative elevations after a rotation to form direct clamping surfaces towards the work piece.

Abstract: A system, in certain embodiments, includes a wedge-lock coupling configured to connect a jaw to an actuator arm of a chuck. The wedge-lock coupling includes a wedge portion having a path of travel between a release position and a lock position, and a locking direction along the path of travel gradually wedges the wedge portion between the actuator arm and the jaw.

Abstract: A rotary chuck includes a housing for rotation about an axis, keyways in the housing which extend radially away from the axis, jaw assemblies slidably received in the keyways and an actuatuing mechanism as well as a speed ring for moving the jaw assemblies along the keyways in accordance with different gear ratios. Each jaw assembly includes an inner jaw keyed to the associated keyway adjacent to the bottom thereof and an outer jaw keyed to the associated keyway near a mouth thereof so that the jaws can slide independently along their respective keyways. Each jaw assembly also has a locking device for locking its jaws together when they are opposite one another to prevent their relative radial movement and means enabling release of the locking device from the outside to permit ready removal of the outer jaw from its keyway.

Abstract: A system, in certain embodiments, includes a wedge-lock coupling configured to connect a jaw to an actuator arm of a chuck. The wedge-lock coupling includes a wedge portion having a path of travel between a release position and a lock position, and a locking direction along the path of travel gradually wedges the wedge portion between the actuator arm and the jaw.

Abstract: A system comprises a machining device which comprises at least one chuck and at least one jaw detachably connected to said chuck, as well as a jaw exchanging device cooperating with said machining device. The chuck is provided with at least one locking element which can be moved in a locking direction and in an opposite direction, from a jaw releasing position to a jaw locking position, and vice versa, by means of the jaw exchanging device. The jaw exchanging device is provided with moving means for moving the jaw with respect to the chuck in said releasing position. The chuck is provided with a rotatable operating pin extending transversely to the locking direction, by means of which the locking element can be moved from the releasing position to the locking position and vice versa. The jaw exchanging device is provided with a connecting element to be connected to the operating pin, by means of which connecting element the operating pin can be rotated.

Abstract: A system, in certain embodiments, includes a wedge-lock coupling configured to connect a jaw to an actuator arm of a chuck. The wedge-lock coupling includes a wedge portion having a path of travel between a release position and a lock position, and a locking direction along the path of travel gradually wedges the wedge portion between the actuator arm and the jaw.

Abstract: A system, in certain embodiments, includes a cutting tool, a drive and a chuck rotatable by the drive. The chuck includes multiple actuator arms, multiple jaws and multiple spring-loaded lock pins coupling the respective jaws to the respective actuator arms.

Abstract: A quick change jaw system for chucks is provided. The quick change jaw assembly includes a master jaw including a first pair of coplanar abutment surfaces defining a first aperture; a clamping device including a dovetail portion being disposed in the first aperture of the master jaw, wherein the dovetail portion rests above the first pair of coplanar top surfaces of master jaw; a top jaw formed with a groove longitudinally extending along a length of the top jaw, the groove being complementary to the dovetail portion and configured for engaging the dovetail portion, the top jaw including a second pair of coplanar abutment surfaces extending along opposite sides of the groove; and a cam for actuating the clamping device for urging the second pair of coplanar abutment surfaces of the top jaw into coengagement with the first pair of coplanar abutment surfaces of the master jaw.

Abstract: A base jaw and a top jaw of an implement clamping system, which can be plugged into each other and which comprise engaging surfaces configured together into cuneal manner and limiting the depth of penetration between the two jaws. The wedge angle is at least 85° or more, but at most 140°, thereby substantially avoiding jamming the engaging surfaces while nevertheless the top jaws are held in place in all directions by the base jaws.

Abstract: A clamping device for fixing a machined part to a processing axis in a machine tool including the processing axis, a clamping head which is rotatable thereabout and with clamping elements floatably arranged thereon.

Abstract: A jaw and a related jaw assembly, the jaw assembly having a master jaw with a longitudinal axis and top and bottom surfaces, first and second side surfaces, a master jaw bore extending longitudinally therein between the top and bottom surfaces, and a channel extending from the first side surface to the second side surface generally transverse the longitudinal axis, and a top jaw adapted to be coupled to the master jaw and defining a top jaw bore positioned in substantial alignment with the master jaw bore.

Abstract: A diaphragm chuck (1) with clamping jaws (3) inserted in its chuck body (2) in a driven connection with a diaphragm (4) that can be deformed by an axially adjustable actuator (5) and is provided with clamping jaws (3) with contact pieces (22), in which counterweights (8) assigned to the clamping jaws (3) are inserted into recesses (7) of the chuck body (2) and the clamping jaws (3) can be clamped against the diaphragm (4) by means of quick-clamping devices (31) engaging in the contact pieces. The contact pieces (22) are each provided with an intermediate element (101) in the area between the clamping jaws (3) and the quick-clamping devices (31) by means of which the flexural moments and/or rotational torques created by the quick-clamping device (31) can be eliminated and it is possible to transmit exclusively axially vectored tensile forces onto the clamping jaws (3).

Abstract: A workholding chuck can use actuating members that pivot within a non-split unitary front bearing. The non-split unitary front bearing can include pockets in its central bore that can allow a spherical section of an actuator arm to be inserted into the bearing. The spherical section can include radially recessed areas to facilitate the insertion into the bearing. The jaws can be retained to the actuator arms through the use of a quick-release assembly. The quick-release assembly allows the jaws to easily and quickly be changed to allow the chuck to grasp different workpieces.

Abstract: A diaphragm chuck assembly having clamping jaws disposed in a chuck body and in driven connection with a diaphragm deformable by an axially adjustable actuator, the clamping jaws having contact pieces, in which counterweights are disposed in recesses of the chuck body and the clamping jaws are clamped against the diaphragm by means of quick-clamping devices engaging in the contact pieces, the contact pieces being arranged in the diaphragm and in the counterweights with radial play. The clamping jaws are supported against a first surface extending axially in parallel to the chuck body in the clamping position and against a second reference surface extending at right angles to the first reference surface and into the diaphragm. The clamping jaws can be changed in a short time and the clamping jaws can be replaced without having to be reground.

Abstract: A quick change jaw system for chucks is provided. The quick change jaw assembly includes a master jaw including a first pair of coplanar abutment surfaces defining a first aperture; a clamping device including a dovetail portion being disposed in the first aperture of the master jaw, wherein the dovetail portion rests above the first pair of coplanar top surfaces of master jaw; a top jaw formed with a groove longitudinally extending along a length of the top jaw, the groove being complementary to the dovetail portion and configured for engaging the dovetail portion, the top jaw including a second pair of coplanar abutment surfaces extending along opposite sides of the groove; and a cam for actuating the clamping device for urging the second pair of coplanar abutment surfaces of the top jaw into coengagement with the first pair of coplanar abutment surfaces of the master jaw.

Abstract: A system, in certain embodiments, includes a wedge-lock coupling configured to connect a jaw to an actuator arm of a chuck. The wedge-lock coupling includes a wedge portion having a path of travel between a release position and a lock position, and a locking direction along the path of travel gradually wedges the wedge portion between the actuator arm and the jaw.

Abstract: A workholding chuck can use actuating members that pivot within a non-split unitary front bearing. The non-split unitary front bearing can include pockets in its central bore that can allow a spherical section of an actuator arm to be inserted into the bearing. The spherical section can include radially recessed areas to facilitate the insertion into the bearing. The jaws can be retained to the actuator arms through the use of a quick-release assembly. The quick-release assembly allows the jaws to easily and quickly be changed to allow the chuck to grasp different workpieces.

Abstract: A workholding chuck can use actuating members that pivot within a non-split unitary front bearing. The non-split unitary front bearing can include pockets in its central bore that can allow a spherical section of an actuator arm to be inserted into the bearing. The spherical section can include radially recessed areas to facilitate the insertion into the bearing. The jaws can be retained to the actuator arms through the use of a quick-release assembly. The quick-release assembly allows the jaws to easily and quickly be changed to allow the chuck to grasp different workpieces.

Abstract: A system, in certain embodiments, includes a cutting tool, a drive and a chuck rotatable by the drive. The chuck includes multiple actuator arms, multiple jaws and multiple spring-loaded lock pins coupling the respective jaws to the respective actuator arms.

Abstract: In an automatic chuck jaw change system, a combined machining lathe capable of positioning with high precision and a robot with lower positioning precision than the combined machining lathe cooperate to automatically change a chuck jaw. The system includes a robot disposed in front of the combined machining lathe, and the robot can be selectively mounted on a front end of an arm thereof with a work hand for operating a work, a chuck jaw, and a nut runner hand for operating a drive mechanism of the chuck. The robot cooperates with a tool for jaw mounted on a tool spindle of the combined machining lathe to automatically change a chuck jaw of a main spindle.

Abstract: A clamping chuck for machine tools comprising a chuck body and a plurality of clamping jaws which can be displaced together radially by means of a drive comprising key rods is disclosed. An actuating mechanism comprising a releasing bolt is rotatably positioned in the chuck body, and a releasing key can be coupled to the releasing bolt, in order to displace the key rod between an upper working position and a lower jaw changing position. The key rod comprises locking means which enable the releasing bolt to rotate out of the rotary position corresponding to the lower jaw changing position of the key rod, into the rotary position corresponding to the upper working position of the key rod, when the toothing of the coupling yoke is engaged with the counter-toothing of an associated clamping jaw.

Abstract: A workholding chuck can use actuating members that pivot within a non-split unitary front bearing. The non-split unitary front bearing can include pockets in its central bore that can allow a spherical section of an actuator arm to be inserted into the bearing. The spherical section can include radially recessed areas to facilitate the insertion into the bearing. The jaws can be retained to the actuator arms through the use of a quick-release assembly. The quick-release assembly allows the jaws to easily and quickly be changed to allow the chuck to grasp different workpieces.

Abstract: A chuck has a chuck body rotatable about a chuck axis, a plurality of holders angularly spaced about and radially displaceable on the body and each formed with an outwardly flared seat centered on a respective seat axis, and an actuator for radially displacing the holders on the body. Respective jaws on the holders each have an inwardly tapered stem complementary to and engaged snugly in the respective seat. Respective locking elements in the holders are each displaceable into a locking position securing the respective stem in the respective seat.

Abstract: A chuck comprises: a chuck body attached to a spindle of a machine tool; master jaws attached to the chuck body along the normal of the chuck body and formed with T-shaped grooves extending along the length thereof; T nuts having tops and trunks, the tops being slidably fitted in the T-shaped grooves of the master jaws; gripping claws having work holding surfaces and grooves for engagement with the trunks of the T nuts; and eccentric shafts inserted into holes formed across the T nuts and the gripping claws and used for attaching the gripping claws to the T nuts. The holes extend across the T nuts and the gripping claws which are engaged with one another. The gripping claws have large reshaping margins at work holding surfaces thereof.

Abstract: A chuck has a chuck body adapted to be rotated about a chuck axis and a plurality of elongated jaw arms angularly spaced about the axis, pivotal in the chuck body about respective guide axes extending secantally of the chuck axis, and axially slidable in the body. Each jaw arm has a front outer end formed with a generally axially extending and radially inwardly directed outer face and an axially outwardly and forwardly directed inner face extending radially inward from an axially inner end of the outer face. Each outer face converges axially outward with the chuck axis and forms a small acute angle with the chuck axis. Respective jaw inserts each have a pair of faces complementary to and flatly engaging the respective jaw faces. These inserts are releasably secured to the jaw outer ends with the insert faces bearing on the jaw faces. The faces are planar. In addition each insert is formed with at least one throughgoing hole extending substantially parallel to the outer insert face.

Abstract: The jaw assembly includes a master jaw and an insert jaw. An engagement surface on the master jaw provides a mounting surface for the insert jaw. The master jaw is contoured to provide a minimum of mass opposite the mounting surface and opposite the engagement surface to minimize the total rotating mass when the jaw assembly is in operation. In operation, a force is applied substantially perpendicular to the engagement surfaces between the insert jaw and master jaw such that the engagement surface experiences the force rather than the insert fastener.

Abstract: A chuck comprises: a chuck body attached to a spindle of a machine tool; master jaws attached to the chuck body along the normal of the chuck body and formed with T-shaped grooves extending along the length thereof; T nuts having tops and trunks, the tops being slidably fitted in the T-shaped grooves of the master jaws; gripping claws having work holding surfaces and grooves for engagement with the trunks of the T nuts; and eccentric shafts inserted into holes formed across the T nuts and the gripping claws and used for attaching the gripping claws to the T nuts. The holes extend across the T nuts and the gripping claws which are engaged with one another. The gripping claws have large reshaping margins at work holding surfaces thereof.

Abstract: A jaw assembly for a jaw chuck for holding a workpiece to the spindle of a machine, such as a lathe, includes an intermediate coupling member that engages a master jaw slot formed in a master jaw which is disposed in a radial guide formed in the body of the chuck. A retaining mechanism secures the intermediate coupling member within the master jaw slot. A top jaw is configured to be connectively engaged with the intermediate coupling member by inserting the intermediate coupling member into a top jaw slot. The top jaw is held securely to the intermediate coupling member, and, accordingly, to the master jaw, when the retaining mechanism is tightened. During top jaw change-out the retaining mechanism is released, thereby permitting the top jaw to be disengaged from the intermediate coupling member while still loosely retaining the intermediate coupling member within the master jaw slot.

Abstract: In a chuck (1) with moveable base jaws (11) inserted in radial grooves (3) in a chuck body (2) with each base jaw (11) having a releasable top jaw (21) attached to it, a joining piece (12) protruding towards the top jaw (21) is formed onto each base jaw (11) and engages in an accommodation opening (22) in the top jaw (21). Furthermore, the top jaws (21) can be clamped onto the base jaws by means of quick clamping devices (31) arranged in the top jaws (21) and the joining pieces (12). This embodiment means that the top jaws (21) of the chuck (1) can be replaced very quickly and in a simple operation, whilst a secure attachment of the top jaws (21) onto the base jaws (11) is guaranteed at all times.

Abstract: In a diaphragm chuck (3) with clamping jaws (3) which are in a drivable connection with a deformable diaphragm (4) by means of jaw carriers (6) and in which counterweights (8) allocated to the clamping jaws (3) are inserted in the chuck body (2), the clamping jaws (3) are provided with axially aligned joining pieces (23) which are held in the counterweights (8). The clamping jaws (3) can be clamped together with the jaw carriers (4) and the diaphragm as well as with the counterweights (8) by means of quick clamping devices (31) which engage in the joining pieces (23).This embodiment achieves a situation in which the clamping jaws (3) can be changed rapidly and in a straightforward procedure by releasing the quick clamping devices (31) by means of a tool which can be inserted radially from the outside into the chuck body (2).

Abstract: A quick-change jaw assembly for use in machining operations. The assembly includes a top jaw which may be removed from a chuck and thereafter repositioned on the same or a different chuck without losing the accuracy previously established through machining of such jaws.

Abstract: An adjustable quick change chuck jaw apparatus for attachment to a master jaw in the front face of a rotary chuck allows a machinist to quickly change the chuck jaws from one diameter to another. A generally rectangular jaw body is connected to the master jaw of a rotary chuck and extends radially outward from the central rotational axis of the chuck. A jaw member is slidably mounted on one side of the jaw body to travel longitudinally relative thereto and has a workpiece gripping portion extending perpendicularly outward. A rotatable shaft mounted in the jaw body has a threaded segment configured to become engaged with mating threads on the jaw member when rotated to an engaged position and to become disengaged therefrom when rotated to a disengaged position. A spring biased locking pin in the jaw body allows selective engagement with the shaft to prevent rotation thereof in a locked position and to become disengaged therefrom to allow rotation in an unlocked position.

Abstract: A rotary chuck having a plurality of quick change jaw assemblies each including a master jaw carried by the chuck body and a top jaw releasably secured to the master jaw by a single retaining fastener having a shank including a frustoconical portion. A resilient roll pin carried by the top jaw bears upon and is compressed by the frustoconical portion. The compressed roll pin exerts a resilient biasing force which acts upon the top jaw to continuously urge an arcuate reference surface on the top jaw into coengagement with a complementary reference surface on the master jaw. A hardened locking pin carried by the jaw assembly bears against a frustoconical head on a locking fastener threadably engaged with the master jaw to prevent relaxation of the resilient biasing force provided by the roll pin when the jaws clampingly engage the I.D. of a tubular workpiece.

Abstract: A chuck jaw assembly for securing work material upon a machine tool, the assembly includes a jaw and replaceable inserts. The jaw provides a mounting means allowing jaw inserts to be quickly replaced by removing one screw, furthermore inserts are provided which allow both larger diameter and smaller diameter work pieces to be accomodated without replacing the jaws.

Abstract: A top jaw assembly for mounting upon the master jaw of a chuck for a lathe includes a mounting base and a top jaw. The mounting base contains two bores which facilitate securement to the master jaw, and a threaded hole. The top jaw is secured to the mounting base by way of a bolt that engages the threaded hole in the mounting base. Movement of the top jaw is prevented by slidably interengaged axial and transverse structure.

Abstract: A chuck jaw assembly includes a base and a removable jaw. A tongue and groove interconnection is provided between the base and the jaw in the form of a longitudinally tapering dovetail. As the tongue is pushed along the groove, its sides are tightly wedged within the groove. At the same time, the tongue is pulled downwardly into the groove so as to firmly seat the jaw on the base.

Abstract: A top jaw for attachment to a master jaw slidable radially in a front face of a rotary chuck toward and away from a central rotational axis of the chuck, the top jaw being suitable for alternate gripping of the inside and outside periphery of a tubular workpiece. When positioned for gripping the outside periphery of a workpiece the top jaw includes a base having a radial locating face and a second locating face directed centrally of a chuck and an insert having a radial locating surface and a transverse locating surface facing away from the chuck axis and cooperating with said base second locating face. One of the base and insert have a slot with side locating faces perpendicular to the radial locating face and the other of the base and insert have a projection with locating surfaces perpendicular to the radial locating face, each opposing an associated one of the side locating faces. A fastener connects the insert to the base.

Abstract: An independent jaw insert locks in a fixed location. Using a post, the post has a flat extending to a transverse groove. An inserted rod locks the post. In addition, a set screw having a point lands in a dimple on the post; two such set screws apply a pinching action for post clamping and registration.

Abstract: A locking jaw assembly having a workpiece clamping top jaw securely interconnectable to a master jaw by a key locator and a lock bolt wherein the top jaw may be readily removed from the master jaw by simply loosening the lock bolt and another top jaw may be readily interconnected to the master jaw with repeatable precision by retightening the loosened lock bolt. The secure interconnection of the top jaw to the master jaw by the key locator and lock bolt is augmented by a lip portion of the master jaw received in a complementary shaped groove disposed on a flange of the top jaw wherein forces exerted by the workpiece on the top jaw tend to move the top jaw into closer contact with the master jaw and relieve tensile stresses on the key locator.

Abstract: A jaw carrier arrangement is provided with a main jaw carrier which removably mounts a top jaw. The jaw carrier has a bore opening outwardly through a front face for receiving a rear support post provided on the top jaw. A clamping structure is provided on the jaw carrier to securely and rigidly hold the top jaw in snug engagement with the front face. The clamping arrangement includes radially inner and outer clamping members having opposed riblike wedges which project inwardly toward the post for engagement within wedgelike grooves which are formed on diametrically opposite sides of the post and extend perpendicularly thereacross.

Abstract: A power chuck includes a body, a plurality of work engaging jaws, a plurality of rocker arms carrying the jaws, and plurality of swivel mountings connecting the rocker arms to the body. The power chuck also includes a plurality of slide members connected to and matingly engaging the rocker arms and reciprocable actuator disposed centrally of the rocker arms and operatively cooperating with the elide members. Reciprocatory movement of the actuator along the slide members rocks the rocker arms in the swivel mountings and moves the jaws radially relative to each other.

Abstract: A top jaw system for securing a top jaw in position above a chuck on a milling machine, lathe or the like is provided. The system generally includes a base jaw, top jaw, master jaw, and a conventional jaw nut. The base jaw includes a bottom portion and a portion and a wedge portion. The top jaw is removably attached to the wedge portion by a pin while the bottom portion is removably attached to the jaw nut by removable mounting bolts. The jaw nut is disposed within a channel of the master jaw. The top jaw can be quickly replaced by the removable of the pin.

Abstract: A power chuck includes a body, a plurality of work engaging jaws, a plurality of rocker arms carrying the jaws, and a plurality of swivel mountings connecting the rocker arms to the body. The power chuck also includes a plurality of slide members connected to and matingly engaging the rocker arms and a reciprocable actuator disposed centrally of the rocker arms and operatively cooperating with the slide members. Reciprocatory movement of the actuator along the slide members rocks the rocker arms in the swivel mountings and moves the jaws radially relative to each other.

Abstract: A chuck with radially adjustable base jaws and exchangeable clamping jaws is provided. The toothings of the base jaws intermesh with respective toothings of the clamping jaws. The base jaws and the clamping jaws are coupled by respective keys which are adjustable relative to one another by an amount corresponding at least to the height of the intermeshing toothings. The adjustment is carried out by a clamp bolt which extends through the shaft of the key and which is provided with a conical clamping surface. The clamp bolt is supported at a rotatably mounted threaded elements or spindle such that the key may be adjusted in the axial direction of the key shaft by the rotation of the threaded element or spindle due to the cooperation of respective counter surfaces provided at the threaded element or spindle with the clamping surfaces of the clamp bolt. Due to this arrangement it is possible to connect and release respective clamping jaws from the base jaws in a very short period of time.

Abstract: A top jaw system for securing a top jaw in position above a chuck on a milling machine, lathe or the like is provided. A protrusion extends upward from the chuck and is preferably attached to the chuck by rigid attachment to a jaw nut which is positioned in a common master jaw on the chuck. The protrusion has a pair of flat faces which extends upward and over the jaw nut to form acute angles with the jaw nut. A top jaw having a slot sized to receive the protrusion is placed over the protrusion. The top jaw has a pin aperture extending through the top jaw through the slot at a right angle to the protrusion when the top jaw is placed on the protrusion. When the top jaw is placed on the protrusion, an elongated pin having a pair of flat surfaces extending along its elongated axis is placed in the pin aperture. One of the flat faces of the protrusion is pushed into contact with one of the flat surfaces of the pin.