In various embodiments an apparatus is presented for securing a structure such as a door, window, hatch, or gate that moves between an open and a closed position relative to a fixed structure to provide or deny access to a compartment, a room, an outdoor area, or a facility. Various embodiments provide a delay in opening the closure of sufficient duration to frustrate a rapid activation that might be desired by a person who is attempting to pass through the closure for some illicit purpose. Typically, hydraulics are used to activate the apparatus and no electrical energy or electronic signals are employed. In one embodiment, a plurality of actuations of a hand lever operates a hydraulic pump that moves a locking bolt from a first position in which a locking bolt is engaged with a recess in the fixed structure (preventing opening of a gate) to a second position in which the locking bolt is disengaged from the recess to permit opening of the gate.

A magnetic latch for industrial environments includes fixed magnetic pole pieces that may be sealed within a housing to resist environmental contamination and which provide for perpendicular engagement faces for use with gates having a rolling or swinging configuration. An RFID tag reader may be incorporated into the magnet assembly of the latch for reading a specially encoded RFID tag in a keeper portion of the magnetic latch.

A door handle device for a vehicle includes a door handle configured to be supported by a door panel, the door handle including a first handle case arranged to have a void relative to the door panel, a second handle case fixed to the first handle case at a side opposite from the door panel, and a lock command detection sensor including a lock detection signal processing circuit fixed to an inner side of the first handle case, a circuit connection portion electrically connected to the lock detection signal processing circuit, and a lock detection electrode assembled on the second handle case in a state to be arranged along an inner surface of the second handle case, the lock detection electrode being electrically connected to the circuit connection portion in a state where the second handle case is fixed to the first handle case.

A door opening preventing apparatus for a vehicle includes an outer door handle mounted on an outer surface of a door panel, a door opening lever mounted on an interior of the door panel to angularly rotate and interlocking with the outer door handle when the outer door handle is opened, and a latch cable connected to the door opening lever, wherein a separate balance weight is disposed at an upper end of the door opening lever to contact the door opening lever, and the door opening lever is pushed by the balance weight outward due to a forward inertial force during a side collision of a vehicle, and only the balance weight is angularly rotated inward by a reverse inertial force.

A locking mechanism (1) for a vehicle seat, particularly for a motor vehicle seat, includes a latch that is to be interlocked with an opposite element (B) and is mounted to be pivotable about a first bearing bolt (13), at least one securing element (25, 31) that secures the latch (11) in the locked state, and a lock housing (5) which supports the latch (11) and the securing element (25, 31). The lock housing (5) has an integrated first stop (5a) for the opposite element (B). The stop (5a) has a damping effect when the opposite element (B) rests against the lock housing (5).

A bracket is provided for anchoring a flexible member such as a chain to a surface in such a way as to allow such member to be repositioned over a range of locations along the bracket, once the bracket has been fastened to the surface. The bracket includes an elongated slot along which the terminal end of the flexible member may slide, thereby permitting the anchoring end of the flexible member to be positioned over a range of positions along the bracket.

A push/pull operating device includes first and second operational devices mounted to two sides of a door. The first operating device includes a first bracket having a plurality of non-circular mounting holes. Two engaging rods extend through two of the mounting holes of the first bracket, the door, and a latch device mounted in the door. Each engaging rod has a limiting portion fixedly received in one of the mounting holes. A head of each engaging rod presses against the first bracket. The second operational device includes a second bracket having a plurality of non-circular mounting holes. A bolt is extended through one of the mounting holes of the second bracket and the door and engaged with one of the engaging rods. A head of each bolt presses against the second bracket. Thus, the first and second brackets are securely fixed to the sides of the door.

A latch assembly includes a chassis, a latch bolt movably mounted on the chassis and having a closed position for retaining a striker and an open position for releasing the striker, and a pawl having an engaged position at which the pawl is engaged with the latch bolt to hold the latch bolt in the closed position and a disengaged position at which the pawl is disengaged from the latch bolt thereby allowing the latch bolt to move to the open position. The pawl is rotatably mounted via a pawl pivot pin about a pawl axis, and the pawl pivot pin includes a first arcuate portion having a first radius about the pawl axis. A cross-sectional area of the pawl pivot pin, taken perpendicular to the pawl axis, is greater than an area of a circle having the first radius.

Embodiments of the present invention comprise a platform attachment for use with a power hand tool which has a housing with a front nose portion with a rotary output shaft extending therefrom, and a tool holding mechanism on the output shaft for holding a tool, the attachment comprising a mounting component having an opening generally aligned with the output shaft through which a tool can extend, a platform component having a base portion and a platform portion, the base portion being adjustably attached to the mounting component, the platform portion having an outer generally planar main surface that is perpendicular to the axis and having an opening through which a tool can extend, and a generally planar secondary surface that extends downwardly from the main surface at a predetermined angle relative to the axis, and a mechanism for releasably locking the platform component on the mounting component.

A method of determining an optimized face cone element for spiral bevel and hypoid gears. The form of the root fillet of one member of a gear pair is determined and that from is transferred to the tip of the other member of the gear pair. With the inventive method, tooth root-tip clearance is optimized and the contact ratio is maximized while avoiding root-tip interference between mating gear members.

A machine tool re-machines a workpiece after positioning drive motors, a hob and the workpiece by stopping the drive motors with the rotational positions of the drive motors, the hob and the workpiece corresponding to their respective zero positions. For this purpose, a drive control section recognizes, based on the rotational-speed ratio of the drive motor corresponding to the hob and the hob and/or the rotational-speed ratio of the drive motor corresponding to the workpiece to the workpiece, and detection signals from detection sensors detecting that the rotational positions of the drive motors are at their respective zero positions, detections signals when the rotational positions of the drive motors and the rotational positions of the hob and the workpiece correspond to their respective zero positions, and stops the drive motors with the rotational positions of the drive motors, the hob and the workpiece corresponding to their respective zero positions.

A method of manufacturing bevel gears with a tool, such as a tapered milling tool (16), wherein the tool is located at a position offset (Rw) from the center position of a conventional face milling cutter and the tool follows a path, such as a circular arc path, during machining.

The table on which a workpiece is put can travel on a guide rail mechanism relative to a working head with a cutting tool mounted thereon. The table is connected through a nut to a ball screw part to move in an axial direction thereof as the ball screw part rotates. One end of the ball screw part is supported by a bearing and the other end is connected to a servomotor to be rotationally driven. A hollow part is provided in the table to receive therein a damper mechanism part, which comprises a spring, a damper, and a weight, the table and the weight being arranged to enable traveling separately on guide rails. Thereby, even when the workpiece is heavy, the weight can move relative to the table to effectively damp vibrations of the table in a feed direction.

An interface element between a first tool element and a second tool element includes a projection on one of the first and second tool elements and a cavity that receives the projection on the other of the first and second tool element. The cavity includes inner contours which are designed to receive polygonal and/or stellate projections.

A path display apparatus includes a first position command acquiring unit that acquires first position command for motors, a first position feedback acquiring unit that acquires first position feedback of each of the motors, a correction data acquiring unit that acquires correction data generated for each of the motors, a second position command calculating unit that subtracts the correction data from the first position command to calculate a second position command, a second position feedback calculating unit that subtracts the correction data from the first position feedback to calculate second position feedback, a command path display unit that displays a command path of the tip point of the tool, based on the second position command; and a feedback path display unit that displays a feedback path of the tip point of the tool, based on the second position feedback.

Methods and devices for milling a channel-shaped cavity by a five-axis computer numerical control (CNC) machine by selecting a workpiece to be machined, determining cutting tool flow along the channel-shaped cavity, determining cutting tool in-depth penetration, determining a trochoid path, and determining auxiliary movements.

A pallet changing device (40) for changing pallets on a machine tool comprises a changing device (15) including connecting elements (26, 28) for releasably connecting the pallet changing device (40) to pallets (7, 8), a rotational drive (19) for rotating the changing device (15) in a working plane (18), and a lifting device (20) for raising and lowering the changing device (15) and thus the working plane (18) within a workspace (21). The rotational drive (19) is arranged outside the workspace (21).

A system and method for modifying a gas turbine engine in the field to drill a series of cooling holes in a turbine rotor disk made of a superalloy. A portable field repair system includes a stand configured to receive, support, and position a turbine rotor disk, a drill having a self-feeding spindle and configured to automatically drill a predetermined depth through a superalloy and to automatically stop upon completion, a drill guide configured to coordinate the drill with a plurality of radial axes associated with a precise hole pattern to be cut and a drill mount configured to mechanically couple the drill to the drill guide and to position the drill during the modification of the gas turbine engine turbine rotor disk.

A self-service, fully-automatic kiosk for duplicating keys includes a kiosk housing having a customer interface for receiving payment from a customer for the purchase of at least one duplicate of the customer's key. A key-receiving entry in the housing receives at least a portion of the customer's key to be duplicated, and a key analysis system within the housing analyzes the blade of a key inserted in the key-receiving entry to determine whether the inserted key matches one of a group of preselected key types and, if so, which preselected key type is matched. A key blank magazine within the housing stores key blanks for each of the preselected key types. A key blank extraction system extracts from the magazine a key blank for the preselected key type matched by the blade of the key inserted in the key-receiving entry. Then a key duplicating system within the kiosk replicates the tooth pattern of the blade of the key inserted in the key-receiving entry, on the blade of the extracted key blank.

The face miller is equipped with a plurality of plate-shaped hard material cutting inserts that are distributed over the circumference. The hard material cutting inserts are located on a graduated circle in pockets of a blade carrier and have a main cutting edge, which is adjusted at a cutting edge angle smaller than 90° relative to the working plane of the miller. In order to ensure maximum machining performance at a good service life, the cutting edge angle is selected to range between 10° and 30°, wherein the main cutting edge at the same time has a slightly convex design. The main cutting edge transitions into the secondary cutting edge via a transition radius having a value that ranges between 0.5 and 1.5 mm. The axial rake angle ranges between 20 and 30°. According to an advantageous further development, the radial rake angle ranges between −6° and −10°.

A cutting machine for gear shaping or the like is provided. The cutting machine includes a gear shaping head. The gear shaping head has a ram that is guided by and reciprocates along a linear guide mounted between a saddle of the gear shaping head and the ram. At least one linear motor reciprocates the ram along a stroke axis relative to the saddle. The ram also carries a rotary drive and a spindle that reciprocate in unison with the ram. The rotary drive directly drives the spindle to journal the spindle through incremental angular positions during gear shaping.

Apparatus, methods, and other embodiments associated with a key duplication machine are described. In one embodiment, an assembly for duplicating a master key includes an optical imaging device, a logic, a clamping assembly, and a cutting member. The optical imaging device is capable of capturing an optical image of at least a portion of the master key. The logic is capable of determining a key pattern of the master key from the optical image of the master key. The clamping assembly is capable of clamping a key blank and the cutting member is capable of cutting a key pattern into said key blank.

A method, network device and system for remote direct memory access (RDMA) over Converged Ethernet (RoCE) packet sequence acceleration are disclosed. The network device comprises one or more functionality components for communicating with a host system. The host system is configured for implementing a first set of functionalities of a network communication protocol, such as RoCE. The one or more functionality components are also operable to implement a second set of functionalities of the network communication protocol.

The machine tool system includes a machine tool, a loader and a support frame structure. The machine tool includes a bed and a processing equipment disposed above the bed to process a work. The loader includes a guide unit disposed above the machine tool and a movable body movable along the guide unit to load and unload the work relative to the processing equipment. The support frame structure includes left and right stands installed on a floor surface at left and right sides of the bed to support the guide unit from below and a reinforcement member inserted in a throughhole, which is provided in the bed so as to extend in a leftward and rightward direction, in a non-contact fashion without contacting an inner face of the throughhole, with left and right ends thereof connected to vertically halfway portions of the associated stands.

A method of chip-removal machining a tooth gap of a work piece includes executing a first substantially linear plunging movement of the cutting tool along a first plunge vector and machining a region of the work piece near a tooth head of a first tooth flank of the tooth. A substantially transverse movement of the tool along a transverse vector is then executed to machine a region of the work piece near a tooth head of the second tooth flank of the tooth. A second plunging movement of the cutting tool along a vector path is then executed, to an end point of the second plunging movement that lies at a position of the work piece corresponding to the slot depth of the tooth gap to be fabricated. The cutting tool is rotated about an axis of rotation thereof during execution of these steps.

A key duplication system comprising a key duplication housing wherein at least one key receiving aperture on a first side of the housing sized to receive a key blade and at least one key clamp adjacent to the at least one key receiving aperture, the clamp comprising a first clamp arm with a surface topography corresponding to a first key blade surface topography and a second clamp arm with a surface topography corresponding to a second key blade different from the first key blade.

According to one embodiment, an apparatus comprises an interface and one or more processors. The interface receives a request for a web page from a web browser. The one or more processors select a subset of web servers from a resource pool according to a load balancing determination. The one or more processors send the request to at least two of the web servers of the subset before receiving any response from the other web servers. Upon receiving one or more responses from distinct web servers, the one or more processors selects a response to communicate to the web browser.

A retention knob for use with a tool holder that is less prone to distorting a tapered tool holder surface, especially if it is over-tightened. The retention knob includes a knob head, a flange engageable with an end of a tool holder shank, a pilot segment receivable by the counter bore defined by said tool holder shank and a threaded segment spaced from said flange by an undercut segment. The threaded segment is configured so that it has a length that is substantially the minimum length required to achieve maximum thread holding strength. The undercut segment is configured to space the threaded segment from its head so that a distal end of the threaded segment is substantially near the bottom of the tapered bore forming part of the tool holder.

The invention relates to a method for producing a bevel gear wheel, in particular for rudder propellers, the teeth of which have a macro geometry specific to the gear wheels, the teeth of which can be described by flank and profile lines, the flanks of which have a tooth flank micro topography and the bearing surface of which represents the contact region of the inter-meshing teeth. The crown of a tooth flank corresponds to the elevation of the tooth flank center with respect to the tooth flank edge, wherein the course of the height and width crowns of the flank surface is substantially shaped like a circular arc. By means of precise material removal, the micro topography of the tooth flank and thus the bearing surface is optimized firstly in that the material removal is carried out such that the end relief on the tooth flank surface is reduced toward the tooth heel side and the tooth toe side, an area having a greater length and width comes into engagement on the flank and thus an enlarged bearing surface is present, and secondly in that the course of the crown the crown of a tooth flank follows an approximately logarithmic, elliptical and/or an exponential curve shape, which runs through the point of contact, when the ease-off is viewed with no load, in a longitudinal section in the flank sectional surface and/or in a profile section in the profile sectional surface.

Methods of fly-cutting a workpiece are disclosed, and in methods in which the position of a fly-cutting head or its associated cutting element is known as a function of time. Also disclosed are methods of forming features, such as grooves or groove segments, in a workpiece such as a cylindrical roll. The features may be provided according to one or more disclosed patterns. Articles made using tools machined in the manner described are also provided, such as polymeric film or sheeting that exhibit certain beneficial properties.

A stroke controller is mounted on a key duplicator and has a base, a drive shaft, a knob and a driven shaft. The base has a longitudinal shaft hole and a transverse shaft hole. The drive shaft is mounted rotatably through the transverse shaft hole. The knob is mounted on the drive shaft and has a drive gear. The driven shaft is mounted slidably through the longitudinal shaft hole and has a rack section engaging the drive shaft so that rotating the knob drives the driven shaft to slide relative to the base. The stroke controller precisely controls the movement of an original key and a key workpiece clamped on the key duplicator to manufacture a fine key duplicate.

A chip and shaving collection system for a key cutting machine has a trough with a linear first trough drawer rail located on a trough first side and a linear second trough drawer rail located on a trough second side. The trough further has a linear first trough support rail having a general shape of a triangular prism located on a trough first side and a linear second trough support rail having a general shape of a triangular prism located on a trough second side. The system has a plurality of linear support beams located on the support rails. The system has a rigid planar grid member spanning the trough top located on the linear support beams. The system has a drawer that is fluidly sealed located in the trough. The system has a key cutting machine located on the grid member.

A rotary joint device includes attachment grooves formed at positions in an outer peripheral surface of an outer cylinder, each attachment groove being formed so as to straddle a pair of adjacent cylindrical blocks and so as to be exposed from the outer peripheral surface of the outer cylinder, each attachment groove having a bottom surface that is machined to form a flat surface in a state in which the cylindrical blocks are combined, and positioning blocks corresponding to the attachment grooves on a one-to-one basis and each having an attachment phase that is uniquely set to a corresponding one of the attachment grooves in the axial direction and in a circumferential direction of the outer cylinder, each positioning block having an attachment surface corresponding to the bottom surface of a corresponding one of the attachment grooves, the attachment surface being machined so as to form a flat surface.

A machine tool having a motor-driven machine spindle which can be rotated about a spindle axis. The machine spindle has a tool holder arranged at the face. A tool is exchangeably arranged on the machine spindle. The tool has a coupling element which is compatible with the tool holder of the machine spindle. The coupling element has a rear surface pointing toward the machine spindle. The machine tool has at least one galvanic contact point for the electric current or data transmission, the point being arranged between the machine spindle and the tool and rotating together with the machine spindle. The galvanic contact point has a contact element which is arranged at the face of the tool holder on the spindle side, and a contact element which is arranged on the rear surface of the coupling element on the tool side.

A machining apparatus for grinding, milling, polishing or the like of a dental workpiece. The machining apparatus contains a machining tool, a housing to which the machining tool is mounted rotatably about an axis of rotation relative to the housing, and a holding device to which the housing is fixed. The housing is mounted yieldingly movably to the holding device in dependence on forces exerted on the machining tool.

A milling apparatus is provided for cutting desired contours into a workpiece. The apparatus comprises a head that moves relative to a workpiece in a direction of cut. Spindles are supported on the head for rotation about parallel spaced-apart spindle z axes and comprise respective rotary cutters adapted for use in machining operations. A rotary head positioner is configured to be operatively connected between the head and a milling machine and to rotate the head about a head axis. A stagger controller is connected to the rotary head positioner and is configured to provide a desired swath of a cut to be formed in a workpiece by rotating the head to set a corresponding spindle stagger angle value.

In a machine tool having a rotary shaft for use in rotating a tool or a workpiece, a plurality of stable rotation speeds at which the chatter vibrations are expected to be suppressed, and at least one switching rotation speed across which a dynamic characteristic of a rotary shaft system changes are stored. The plurality of stable rotation speeds may be determined from chatter vibrations detected using a vibration detection unit. Optimum rotation speed that is a rotation speed to which a rotation speed of the rotary shaft is changeable without crossing the switching rotation speed is selected from the plurality of stable rotation speeds, and the rotation speed of the rotary shaft is changed to the optimum rotation speed. Thus, chatter vibrations generated during rotation of the rotary shaft can be suppressed effectively.

A ram guiding apparatus 1 of a machine tool is incorporated in a portal type machine tool 2 and provided with a cross saddle 5 that is cross-like in shape, as seen in a side view of the machine tool 2, provided so as to be freely movable in the horizontal direction along a horizontal cross beam 4. The cross saddle 5 has a box 18, both upper and lower faces thereof being open, in a front side of a horizontal part, wherein a first linear guide 21, a second linear guide 22, and a third linear guide 23, respectively serving as linear guides in the box 18 for a ram vertical movement, guide the ram 9 so as to be freely movable only in the vertical direction.

An apparatus for forming a bend in a composite panel is provided. An angle and a radius bend are identified for a bend. A location of the bend in the composite panel is identified. A slot is cut having a curved flange in the composite panel at the identified location in a single pass through the composite panel with a tool, wherein the curved flange has a shape with a bend allowance width and a bend slot width. The bend allowance width is BA=2π*A/360, wherein BA is the bend allowance width, R is a corner radius, and A is a bend angle. The bend slot width is BS=BA−2K(R−T), wherein K is Tan(A/2) and T is a thickness of the composite panel.

A translocation-simulating loading apparatus for the gear grinding machine with the shaped grinding wheel is provided. The apparatus includes a load-receiving test piece disposed on the gear grinding machine with the shaped grinding wheel and a load-exerting component for use in loading simulation. The gear grinding machine enables linear movements along the X, Y, and Z axes, a rotary movement around the Y axis, a rotary movement C around the Z axis, and a rotary movement A around the X axis. An angle α is formed between the axis L of a ball seat of the load-exerting component and the X axis direction of a Y axis component and an angle formed between the normal line of a load receiving face a and the X direction of the coordinate system of the machine tool is α. A detection method for static stiffness distribution is provided.

In a pilot hole of a workpiece made of a difficult-to-cut cast iron, a cutting tool having a leading end to which a cutting insert is attached is inserted to cut the surface of the wall of the pilot hole. At this time, the cutting tool rotates about an axis (α) and also revolves about another axis (β), so that contouring is performed on the workpiece by the tool. The cutting insert is formed of a sintered body having a CBN content of not less than 85% by volume, and the cutting insert has a thermal conductivity of not less than 100 W/(mK).

To provide a tool holder that is capable of exerting a vibration-minimizing effect in a reliable manner using a simple configuration and that is extremely useful for practical application. A tool holder comprising a vibration-minimizing part for minimizing vibration generated in a tool (1) when the tool (1) is used to perform machining, the vibration-minimizing part being provided, on a distal-end side, with tool-holding means for detachably securing the tool (1) and provided, on a proximal-end side, with a shank part (2) to be mounted on a spindle of a machine tool; wherein a plurality of reinforcing parts (4) extending in an axial direction of the tool holder (3) are provided to a peripheral section of the tool holder (3) in a radial direction; accommodating recesses (6) for accommodating a vibration-damping material (5) are provided between the reinforcing parts (4); the vibration-damping material (5) is accommodated in the accommodating recesses (6); and the vibration-damping material (5) and the reinforcing parts (4) form the vibration-minimizing part.

A case mouth chamfer tool utilizes an easily adjustable cutter holder member. The adjustable cutter holder member slides in a dovetail, is adjusted by advancing and retreating a screw, and is held in place by a set screw. The case mouth chamfer tool may be fixed to a micrometer dial threadedly engaging a barrel. A case adapter bearing is fixed to the barrel. The case mouth chamfer tool is adjusted to cut an inside chamfer and the micrometer dial is rotated to adjust the position of the case mouth chamfer tool with respect to the case adapter bearing to precisely adjust the amount of material cut from the case. The case adapter bearing is easily changed to chamfer different cases.

A method of machining bevel gears whereby machining of both flanks of a tooth slot and crowning of the tooth surfaces in the lengthwise direction are realized without an active pivot axis and by a modification of the conventional relationship between the radial and swivel basic settings during gear generating.

A cooling assembly for a machine tool including at least first and second nozzle rings mounted on the spindle housing, respectively defining first and second coolant conduits and respectively including first and second pluralities of nozzles in fluid communication with the respective conduit. Each first nozzle is oriented with an outlet thereof directed toward a first machining zone containing cutting edges of at last one tool having a first length. Each second nozzle is oriented with an outlet thereof directed toward a second machining zone different from the first machining zone and containing the cutting edges of at least one tool having a second length.

The present invention relates to a compensation system for compensating for the drop of the ram in a machine tool, comprising a vertical translation carriage (1) incorporating the application ram, at least one and preferably two perforated plates (2) being arranged on said carriage (1), on each of which there is incorporated a fixed sliding block (3) and movable sliding blocks (4), which blocks are linked with a guide for the transverse movement of the ram, such that the drop of the ram is compensated for by means of the controlled bending of the plates (2).

A master servo motor and a slave servo motor that synchronously drive for rotation a master main spindle provided with a center that supports one end of a work piece and a slave main spindle provided with a center that supports the other end of the work piece are included. Before grinding, a slip detection cycle that detects a limit current value for the servo motors, at which the work piece and the centers slip, is executed and, during grinding, a grinding condition is changed to prevent a slip between the work piece and the centers in advance at the time when any one of current values of the servo motors has reached a slip threshold value set on the basis of the limit current value.

A tool adapter includes an adaptor body having a connection portion structured to be attached to a machine tool and a holder portion disposed opposite the connection portion and a tool receiver structured to receive and couple a portion of a rotary cutting tool therein. The tool receiver is mounted in the holder portion so as to be rotatable to a limited extent. The tool receiver is mounted in the holder so as to be elastically resilient in both the axial and circumferential directions.

Apparatus, systems and methods of 50 CFM exhaust and ventilation fans for bathrooms with grill covers having removable light lens covers, and flaps/ears that allow the housings to mount directly to joists and/or other structural members inside of a ceiling or inside of a wall. The housing can include a mounting plate having a motor with attached impeller thereon, wherein the mounting plate with motor and attached impeller and electrical connectors can be removed as a single unit from the housing for accessing and inspecting interior wire connections during inspection and for ease in replacing parts such as burned out motors overtime.

There is provided a culinary whisk comprising a body including a handle portion and a utility portion connected to the handle portion. The utility portion has a number of loops formed from a plurality of wires, wherein at least one of the wires is provided with a first portion having a non-circular cross section.