Abstract: A system for holding a multiple welled plate during processing comprised of a multiple welled plate, typically containing 96, 384 or more individual wells, each having an open bottom closed by a membrane and a holder for such a plate. The holder is formed with a filter support portion that supports the lower surface of the filter during processing. The holder may optionally be thermally conductive or if not thermally conductive, may include an additional thermally conductive layer between the lowermost surface of the filter and the filter support portion to provide for thermal cycling applications.

Abstract: An apparatus for clamping an object includes a clamp with a first gripping element and a second gripping element that is connected by a pivot rod and includes a resilient element to maintain the clamp in closed position in the absence of applied pressure, and a release mechanism. An arm with a cable encased by a plurality of tubular, cone shaped segments is attached to the release mechanism, which is in turn attached to the clamp and includes either coil springs or bow springs for maintaining tension in the cable when the clamp is in a closed position, and for releasing tension in the cable when the clamp is opened.

Abstract: A hobbyist's tool comprised of a grid-like base member containing a plurality of uniformly shaped and uniformly spaced apart peg openings into which adjustable, flexible arms may be attached. Formed on the lower end of each flexible arm is an elastic bushing designed to fit snugly into one of the peg openings on the base member. Attached to the opposite, upper ends of the flexible arms are clamp, vise, or other retaining members which temporarily hold parts needed to be glued, painted, or otherwise held suspended. The flexible arms are made of a plurality of ball-and-socket joints that enable the part holders to be posed in various orientations and elevations. The flexible arms may be selectively removed and replaced in any of the peg openings on the primary base member to hold different parts. An optional secondary base member is also provided that may be perpendicularly aligned and selectively attached to different locations on the primary base member.

Abstract: A work holder support arm for supporting a work article at a desired orientation with respect to a support structure is provided with a first clamp (12) having clamped and unclamped states for coupling with the support structure. The first clamp (12) has an opening therethrough for accommodating the support structure, and there may be provided a through-hole arranged transverse to the opening. A shaft portion (27) is coupled to the first clamp (12), the shaft portion (27) having a longitudinal bore therethrough arranged to be axial in registration with the through-hole of the first clamp. Additionally, a second clamp (11) couples with the work article and has clamped and unclamped states. A tube portion (14) is coupled to the second clamp (11) for accommodating telescopically therewithin the first shaft portion (27). An expansion portion (30) is arranged coaxially with the shaft portion (27) within the tube portion (14) and is provided with a threaded section.

Abstract: In a multi-table lithographic apparatus in which substrate tables may be exchanged between a first working zone where substrates are loaded onto and removed from the table and a second working zones where wafers are exposed, collision prevention means are provided to prevent collisions between tables in the exchange process. The collision prevention means may be formed of a labyrinth or a revolving door. The exchange process may be controlled by shuttles, optionally including drive means, that are interlinked so that the tables can only be exchanged between zones together.

Abstract: A workpiece support assembly includes an elongated workpiece support structure and a pair of support members pivotally connected to one another towards upper ends thereof. The support members are pivotally movable between an open position and a folded position. The workpiece support structure has a workpiece support surface constructed and arranged to support a portion of a workpiece. The workpiece support assembly further includes a tabletop assembly. The tabletop assembly is movable into a deployed position in which the tabletop is disposed substantially horizontally in overlying relation to the workpiece support structure, with the pair of support members in their open operative position. The deployed tabletop presents an upper tabletop surface to support a workpiece. The tabletop assembly is movable, with the pair of support members in their open operative position, into a storage position which exposes the elongated workpiece support surface.

Abstract: A pipe fitting apparatus includes first and second connector units for releasable connection to respective first and second pipe sections adjacent pipe ends to be coupled, so as to hold the pipe sections relative to one another in the desired relative orientations during welding. Each connector unit has a groove on one face for location against the outside of a pipe, with the longitudinal groove axis extending parallel to the axis of a pipe to which it is secured. The units are adjustably secured together by a pivot coupling having a pivot axis extending transverse to the groove axis for pivotal adjustment of the orientation of the second connector unit relative to the first connector unit, whereby the relative orientation of the first and second pipes to be coupled can be adjusted. A releasable locking device releasably secures the second connector unit at a selected orientation relative to the first connector unit.

Abstract: The present invention relates generally to a pipe fitting table used to temporally support a plurality of pipes being connected. More particularly, the present invention relates to providing welding, cutting and clamping devices on the pipe fitting table to assist an assembler in positioning and joining a plurality of pipes.

Abstract: A mutlilevel clamp device for holding a plurality of frames during gluing procedures. The mutlilevel clamp device includes a plurality of clamps. Each of the clamps comprises a first end wall and a second end wall. A bar extends between and is attached to the end walls. The bar has a channel therein extending between the end walls. A rod is positioned in the channel and extends between the end walls. The rod is rotatably coupled to the end walls and has a free end extending through the first end wall. The rod is threaded. A block is positioned in the channel and extends upwardly out of the channel. The rod extends through the block and threadably engages the block. The block is moved along the channel by rotation of the rod.

Abstract: An implement capable of being mounted for limited articulation on a pole for installation of a guard on an elevated transformer from ground level in which the implement comprises a jaws biased toward one another to grippingly engage a guard of the type having a tongue in a fixed position in said implement for hoisting on the pole to the transformer.

Abstract: A base plate for building devices for clamping workpieces in a defined and reproducible position has first grid points arranged in a uniform grid pattern defined by perpendicularly crossing center lines spaced from one another by a uniform grid pattern spacing. The first grid points describe an ideal surface of the base plate. Each first grid point is a first concave spherical depression having a center point. Each center point is located on a point of interception of the perpendicularly crossing center lines.

Abstract: A workpiece support apparatus includes an elongate primary body having several height adjustable primary support columns which extend vertically from the primary body. One or more arms extend radially from and are pivotally secured to the primary body. The arms pivot about a substantially vertical axis for angular adjustment on a substantially horizontal plane. At least two height adjustable secondary support columns extend vertically from each arm. The workpiece support apparatus is particular adapted for use by welders when welding pipe to form complex branch structures.

Abstract: A plurality of blocks are chained together in alignment over at least one rod, each with a recess for receiving a work piece between adjacent blocks. A second chain of holders may be employed to receive a different portion of the work pieces so the work pieces extend between the chains of blocks, forming a set of chains that may be presented as a unit before a cutting tool to make a cutting process efficient and uniform among work pieces. Further chains or sets of chains may be employed to hold a larger number of work pieces together. Chains of blocks are advanteously mounted on vise plates in plate holes spaced apart from centers of vertical and horizontal neighboring plate holes a same distance, d. Thus, two rods of a set of work piece holders may be positioned at preferred positions on the plate with recesses aligned vertically or horizontally.

Abstract: A clamping device (1) is disclosed for one or several workpieces (2), especially bodywork parts. The clamping device (1) includes one or several clamps (4) which can be positioned on a clamping table. Several parts can be displaced along at least one axis. The clamps (4) comprise a positioning device (13) and a fixing device (10). The positioning device (13) has a height adjustment system (21) and/or angle adjustment system (22) and/or lateral adjustment system (4b). To allow for stepless adjustment over a wide range the positioning device (13) has a coarse adjustment system (43) and a fine adjustment system (44). The fixing device (10) can be configured as a clamping device (35) and simultaneously include the lateral adjustment system (4b).

Abstract: Double end and single end jig apparatus is disclosed having a channel and guide edges for marking window/door trim held in the channel, for subsequent miter cut of corners for mounting the trim around window/door opening, and a set back or margin between the window/door opening and the trim.

Abstract: A stand for supporting and securing an item such as a portable computer comprises a hinged leaf assembly with adjustably positionable clamping members. The clamping members are slidingly secured along outer edges of hingedly connected leaves of the leaf assembly to permit sliding advancement of the clamping members relative to and along the edges of the leaves to which they are attached. An articulated arm is secured at an upper end to the underside of the leaf assembly and at a lower end to the surface relative to which the item is to be supported such as the floor of a vehicle.

Abstract: A race car seat is fabricated of four seat quadrants temporarily secured on seat fitments and welded together. The seat fitments are adjustably positioned on a jig in an optimum position for a race car driver. The jig includes adjustment plates for setting the width, tilt, and height of the seat fitments. The seat quadrants are then removably secured to the fitments and welded together to form a seat corresponding to the optimum configuration set by the position of the fitments on the jig.

Abstract: A corner clamp joining a pair of generally orthogonal elongated members is formed by slicing a generally C-shaped frame form an aluminum alloy extrusion so that the frame includes a member spanning opening with a pressure pad defining one extremity of the opening and an opposite opening extremity face including a threaded hole and a threaded shaft passing through the threaded hole and helically movable therein toward and away from the pressure pad. The members are joined by clamping them together between the pressure pad and the end of the movable shaft. One elongated member may be an I-beam and the other a U-shaped channel with the U opening away from the I-beam. The slice is taken obliquely to the direction of elongation of the extrusion so that the pressure pad has a non-rectangular generally parallelogram shaped face. When assembled, one edge of the pressure pad face extends generally parallel and adjacent to an inner U surface.

Abstract: A work holder support arm for supporting a work article at a desired orientation with respect to a support structure is provided with a first clamp having clamped and unclamped states for coupling with the support structure. The first clamp has an opening therethrough for accommodating the support structure, and there may be provided a through-hole arranged transverse to the opening. A shaft portion is coupled to the first clamp, the shaft portion having a longitudinal bore therethrough arranged to be axially in registration with the through-hole of the first clamp. Additionally, a second clamp couples with the work article and has clamped and unclamped states. A tube portion is coupled to the second clamp for accommodating telescopically therewithin the first shaft portion. An expansion portion is arranged coaxially with the shaft portion within the tube portion, and is provided with a threaded section.

Abstract: A stand for supporting and securing an item such as a portable computer comprises a hinged leaf assembly with adjustably positionable clamping members. The clamping members are slidingly secured along outer edges of hingedly connected leaves of the leaf assembly to permit sliding advancement of the clamping members relative to and along the edges of the leaves to which they are attached. An articulated arm is secured at an upper end to the underside of the leaf assembly and at a lower end to the surface relative to which the item is to be supported such as the floor of a vehicle.

Abstract: A telephone cable splicing tool including a splicing tray, a rod having two ends, with one end engaged with the splicing tray, and vise grip pliers engaged with the other end of the rod.

Abstract: A device for clamping parts, in particular metal sheets, in a motor vehicle mounting line, has a console, a support for the parts that may be secured on a top stop of the console, and a pneumatic clamping device that actuates a pressure piece that can be clamped against the parts mounted on the support. In order to obtain a console made of a few components with various spatial positions of the clamping point between the support and the pressure piece, at its base the console has a clamping block and a centering piece for a stay that can be secured thereon, and the top stop acts with its bottom side as a centering element for the stay that can be secured thereon.

Abstract: An adjustable magnetic jig 20 includes a first magnetic holder 22, and a second magnetic holder 26. A pivoting joint 30 connects the first 22 and second 26 magnetic holders, so that the angle A between the holders may be selectively adjusted. Pivoting joint 30 is also selectively lockable so that angle A can be fixedly maintained. Jig 20 is particularly useful in holding magnetic workpieces 500 in a desired physical relationship so that the two workpieces 500 can be welded together.

Abstract: A fixture for controllably holding a blade and particularly a scissor or scissor element for precise sharpening and shaping including hollow grind and clamshell (convex) sharpening. The fixture comprises an articulable holding arm with at least two movable joints and an extension portion swivelly attached to one of the joints. The extension portion terminates in a holding member for the scissor or scissor element which holding member is freely concentrically rotatable relative to the longitudinal extension axis of the extension portion. The holding member comprises a clamping element for holding the scissor element parallel to the longitudinal extension axis. The extension portion further comprises a position adjustable stop to limit rotation of the holding member to provide a precise angular holding of the scissor element relative to an adjacent sharpening element.

Abstract: A mounting bracket for a workpiece holder which includes a pair of plates which can be coupled together so as to define two openings at their coupled surfaces. The plates are coupled together by threaded members which are located on either side of each of the two openings. One of the openings is cylindrical and designed to receive a workpiece holder. The other opening has a partial spherical bore and is provided with a spherical collar that can receive a support structure. The threaded members can be selectively loosened to allow either or both of the openings to expand.

Abstract: A retaining tool for grasping ends of a broken wire in a wire bundle and maintaining them in fixed relationship, including a thin generally U-shaped body with legs having alligator clips at each end thereof. Spurs are formed along each leg, each spur depending generally perpendicularly from a leg. An optional handle may be formed on the body to extend therefrom. The body may be coated with an electrical insulator or portions thereof may be enclosed by a non-conductive sleeve.

Abstract: A fabrication assembly (10, 18, 24, 30, 38, 44, etc.) for the manufacture of prosthetic and orthotic devices allows various components of these devices to be aligned on a common mast with respect to height, distance, flexion/extension, abduction/adduction and rotation alignment criteria, and each of these criteria can be adjusted apart from the other criteria. There are planar translation components (62, 62') that permit true planar, medial-lateral movement relative to a mast (10) without imposing rotation or angular deflection to a component mounted thereon. Accordingly, the assembly of a prosthetic or orthotic device according to physiological alignment criteria is an efficient step-by-step process, whereas prior art devices required that at least two criteria be adjusted and checked simultaneously. Among the features of the fabricating system are an angular/rotational fixture (38) that allows for separate settings of angular and rotational orientations for a given component.

Abstract: A support structure to aid in the creation of a corner joint between two planar perpendicularly-situated workpieces. The support structure of the invention consists primarily of a horizontal and vertical support surface, with the vertical support surface displaced from the horizontal surface and separated therefrom by a clearance area, such clearance area designed to accommodate excess material present at the formation of the corner joint between the two workpieces. The support structure of the invention may be used to create a single corner joint, or a second support structure may be implemented in conjunction with the first support structure to simultaneously create multiple corner joints. A variety of clamping and fastening implements are disclosed to maintain the workpieces attached to the support structure.

Abstract: Methods and apparatus are provided for developing a complete set of all admissible Type I and Type II fixture designs for a workpiece. The fixture processor generates the set of all admissible designs based on geometric access constraints and expected applied forces on the workpiece. For instance, the fixture processor may generate a set of admissible fixture designs for first, second and third locators placed in an array of holes on a fixture plate and a translating clamp attached to the fixture plate for contacting the workpiece. In another instance, a fixture vise is used in which first, second, third and fourth locators are used and first and second fixture jaws are tightened to secure the workpiece. The fixture process also ranks the set of admissible fixture designs according to a predetermined quality metric so that the optimal fixture design for the desired purpose may be identified from the set of all admissible fixture designs.

Abstract: A device is provided which supports plate-like objects and, while supporting the objects, changes the distance between the objects. The device comprises at least one elongated carrier having movable interconnected spacers. The spacers support the plate-like objects substantially parallel with respect to each other. The spacers can be shifted axially on the carrier between positions between positions of minimum and maximum distance.

Abstract: A welding jig comprising a weld head support mounted on a support surface and one or more tube support pedestals having a top groove for supporting a tube in alignment within the weld head. The pedestals may be threaded to provide a height adjustment of the pedestals.

Abstract: A portable chain type pipe vise that includes a frame, at least two clamping main assemblies, and a clamping sub-assembly. The frame is stably restable on a work surface. The at least two clamping main assemblies are longitudinally movable on the frame, so that at least two pipes can be rested in longitudinal alignment with each other. The clamping sub-assembly is disposed at each of the at least two clamping main assemblies, so that the at least two pipes can be retained in longitudinal alignment with each other.

Abstract: A workpiece holder, particularly adapted for holding eyeglasses lenses (L), comprises a support (12) on which there are arranged two clamps (14, 17, 117) for clamping each a portion of a lense. Each clamp defines an axis (A) which is substantially perpendicular to the portion of lense clamped thereby. Each clamp is positionable and lockable with said axis (A) oriented in any direction at the interior of an ideal cone (A1 - A2) having a vertex through which the said axis (A) is passing. Positioning means (3, 4, 40) are provided for displacing the said support (12) along a horizontal plane with respect to a fixed tool (28).

Abstract: A device for use in assisting a person in folding a flag. The device comprises a band having an internal diameter, a first end and a second end and an intermediate extent therebetween. The band is formed into a circular configuration with first and second ends in alignment. A plate is positioned upon the band opposite the first and second ends. A threaded aperture is formed within the plate. A clipping arm is included and has a first end and a second end and an intermediate extent therebetween. A hole is formed within the first end of the arm. A clip is positioned upon the second end of the arm. A hook arm has a first end and a second end and an intermediate extent therebetween. A hole is formed within the first end of the arm. A hook is positioned upon the second end of the arm. A screw is positioned through the hole within the first end of the clipping arm and within the hole within the first end of the hook arm. The screw is threadably secured within the aperture of the plate.

Abstract: A support structure for laterally supporting a workpiece in a vertical lathe so as to hold the axis of the workpiece aligned with the vertical support axis of the lathe. The support structure includes a rod which is vertically supported on the lathe. The rod supports a movable locator rest assembly. The locator rest assembly includes a horizontally extending rod which terminates in a part rest which can be positioned so as to engage and support the workpiece in a precisely vertical manner.

Abstract: A system for fast, efficient assembly of mechanical component support infrastructures based on a set of interlocking rods and/or tubes and supporting blocks, each block supporting at least two rods/tubes in a precision configuration. The blocks and rods are formed in a particular relative size and shape to allow them to be assembled quickly and easily into a wide variety of configurations, all capable of providing a highly stable and precision infrastructure for supporting equipment in lab and bench setups.

Abstract: A workpiece clamping apparatus for securing a workpiece relative to a planar support surface has a pair of saddle clamp members each provided with a plurality of threaded apertures. A mounting member associated with selected ones of the plurality of threaded apertures is provided for operably attaching saddle clamp members to the planar support surface in a variety of orientations. Each saddle clamp member can engage a portion of a bar clamp. Each saddle clamp member can also engage a portion of a length of pipe which can have pipe clamps thereon.

Abstract: A method for reconfiguring a jig for supporting an elongated workpiece to enable the jig to support two different configurations of the workpiece. The jig has a multiplicity of clamps for holding the workpiece, each clamp mounted at the top of a clamp post and each clamp post supported on a pillar mounted on a fixed solid base. The jig is configured by sliding the posts along slides on the pillars to a first position at which the posts can be placed to position the clamps at the correct elevation to support the workpiece at a first configuration position, and inserting a pin through aligned pairs of holes in each of the clamp post and the pillar to prevent the post from sliding from the first position relative to the pillar. The weight of the clamp post and clamp are counterbalanced with a fluid cylinder connected at one end to the clamp post, and connected at the other end to the pillar.

Abstract: Mandibular distraction osteogenesis can take place by performing corticotomy surgery at two points on opposite sides of the mandible and at the same time attaching an expansible distraction device to the teeth of the mandible on opposite sides of the two points of the corticotomy surgery. The device is then periodically expanded until a desired mandibular length is obtained. The device includes a plurality of bands that are fitted onto the teeth of the mandible and a number of universal expansion screws that are connected to the bands for purposes of distracting the mandible. This device can be assembled with an appropriate appliance assembly tool that precisely positions and aligns the universal expansion screws relative to the bands during assembly thereof.

Abstract: A clamping jaw (10) for a clamping device, adapted to be mounted on a profile member (31) is formed by two separate jaw members (11) and a common rear counter support (12) for said members, which is arranged to transmit clamping forces produced by means of clamping bolts (32) to the two jaw members (11). The jaw members (11) and the counter support (12) have cooperating engagement means (13, 15) for placing and holding the jaw members (11) in predetermined positions in relation to the counter support (12). In order to make it possible to adapt the clamping jaw (10) to profile members of different shape and size, the engagement means (13, 15) are arranged to permit each jaw member (11) to be placed and held in a plurality of different positions in relation to the counter support (12).

Abstract: A workpiece clamping apparatus for securing a workpiece relative to a planar support surface including a pair of contoured block members, each provided with a plurality of slots and apertures and having a base provided with structure for operatively attaching the block members to the planar support surface. A bar clamp has structure for securing a workpiece and further has opposite ends wherein each end of the bar clamp is operably associated with one of the pair of block members. The plurality of slots and apertures are axially aligned in both the vertical and horizontal planes. Each slot is operatively associated with a selected one of the plurality of apertures and is further dimensioned to receive one of the ends of the bar clamp. The plurality of apertures further include at least one aperture formed in the base of each contoured block wherein the at least one aperture is provided with structure for operably connecting the block member to the planar support surface.

Abstract: A clamp structure for holding a workpiece in a vertical position, and which is reconfigurable to enable manufacture of an opposite hand version of the workpiece, includes a plurality of pillars mounted on a fixed solid base and a clamp post on each of the pillars having a top end on which is mounted a clamp. An air cylinder has one end connected to the pillar and an opposite end connected to the clamp post. The air cylinder is connected to a source of air pressure for pressurizing the air cylinder to a pressure sufficient to substantially counterbalance the weight of the clamp post and clamp. A pair of holes in structure mounted on the pillar, and a pair of holes in structure mounted on the clamp post are alignable in pairs for two heights of the clamp for two different configurations of the workpiece, so the clamp structure can be used to clamp two different configurations of the workpiece.

Abstract: A clamping device operable to clamp work pieces together at an obtuse angle. The device includes an elongate support bar having an angle element attached thereto and projecting outwardly at the obtuse angle from the support member. A clamping projection is mounted on a sleeve that is shiftable longitudinally along the support member toward and away from the angle element. A locking mechanism is attached to the sleeve for securing the clamping projection in a selected position on the support member.

Abstract: A releasable screed handle for being operatively secured to a selected screeding member to manipulate the screeding member through the various spreading and smoothing motions requisite in working concrete. The screed handle consists of an elongated handle that is pivotally affixed, at an angle of about 105.degree. from the vertical, to a lockable clamping plier that is capable of receiving and clamping a screed member of selected size and thickness.

Abstract: In order to provide a C-shaped clamp for clamping workpieces, comprising a C-shaped clamp bow, a spindle nut arranged at one end of the clamp bow, a clamping spindle mounted in the spindle nut and a support arranged at the other end of the clamp bow, which can be used in conjunction with auxiliary elements for clamping a workpiece, it is proposed that the clamp bow have a guide section with guide surfaces for guiding infinitely adjustable, auxiliary elements for the C-shaped clamp.

Abstract: A modular device for assembling, wiring harnesses, cables and the like includes a number of elongate elements, a number of cable guiding means, each of the cable guiding means being selectively positionable along different points along the length of one of the elongate elements, and a number of securement means for removably securing the elongate elements in a fixed relationship.

Abstract: A work holder is provided which comprises a work surface having a pattern of apertures across its entire surface. The apertures allow a conventional clamp to secure any work piece to the work surface at any point on the surface. The apertures are circular in shape and of a dimension such that a conventional clamp will not slip from the board. Radially extended flutes are connected to the circular apertures to allow the clamps to be fully extended across a work piece and be essentially locked to the work surface. Half apertures at the edges of the work surface allow the work surfaces to interlock with one another. The interlocking half apertures in combination with their radial flutes allow the work surface to be set up in a wide variety of configurations.

Abstract: A jig for assembling a rebar pier cage wherein certain of the individual jig elements are laterally and longitudinally adjustable to provide a jig capable of assembling rebar pier cages of various sizes and shapes. The jig elements comprise a plurality of rebar stirrup retaining elements removably secured within longitudinal openings in first and second, elongated channel bars which traverse a rectangular work surface in parallel relationship. Opposite ends of the first and second channel bars are slidingly secured within longitudinal openings of third and fourth channel bars which laterally span the opposite, shorter edges of the work surface. Means are provided to adjust the longitudinal spacing between each stirrup retaining element in the first and second channel bars, and also the lateral spacing between the first and second channel bars.

Abstract: A wall-mounted pipe clamp installation and a mounting kit therefor. The kit comprises an elongated wall bracket having its upper and bottom edges in the form of downwardly and upwardly facing and opposing channels respectively and a pair of pipe end receiving sockets slidably mountable in the bracket. Each socket has a base with exposed upper and lower edges spaced to fit in bracket supported relationship in the channels and a projecting socket formation for receiving a pipe end therein. Each socket formation is preferably provided with a set screw to secure therein the free pipe end of each pipe clamp of a pipe clamp installation.

Abstract: An apparatus for holding the stator of a vessel rotatable about an axis of rotation, includes a pivotable swing arm having a first end and a second end, the second end having an engagement portion for contacting the stator of a rotating vessel. A support is connected to the first end of the swing arm and has an axis spaced from and substantially parallel to the axis of rotation. The support cooperates with the swing arm to permit the swing arm to pivot toward and away from the stator. A detent finger, located in the swing arm cooperates with the stator to hold the stator against rotation when the swing arm is in a predetermined angular position, and maintains the stator in a fixed position relative to the swing arm during a centrifuge operation. Finally, a detent cam assembly resists pivotal movement of the swing arm when the swing arm is in the predetermined angular position.