Abstract: A differential housing is configured to support a plurality of bearings. The differential housing includes a first bearing surrounding member provided to surround a first bearing included in the plurality of bearings. The differential housing includes a second bearing surrounding member provided to surround a second bearing included in the plurality of bearings; and a connecting member that connects the first bearing surrounding member and the second bearing surrounding member, at least a part of the connecting member being embedded in a wall that is made of a base material of the differential housing. Each of the first bearing surrounding member, the second bearing surrounding member, and the connecting member is constructed of a material having a smaller linear expansion coefficient than that of the base material of the differential housing.

Abstract: A cruise control system of a motor vehicle includes additional functionality to address increasing vehicle speed on a down gradient. A downshift is commanded upon detection of repeated or prolonged activation of a speed-down control, the additional engine braking reducing vehicle speed to cruise speed in a manner which is within driver expectation.

Abstract: A method is provided for shifting a transmission, more particularly an automatic planetary transmission, having multiple non-positive shift elements and at least one positive shift element. The transmission can assume particular transmission states according to current shifting states of the shift elements, each transmission state having a particular transmission ratio between a transmission input and a transmission output. At least two transmission states have identical transmission ratios. To shift into a first of the at least two transmission states that have identical transmission ratios, only non-positive shift elements are engaged. By contrast, to shift into a second of the at least two transmission states that have identical transmission ratios, at least one positive shift element is engaged.

Abstract: A hydraulic pressure control device of a vehicle driving device, the hydraulic pressure control device includes a range switcher having a first signal solenoid valve capable of supplying a first signal pressure and a spool switchable between a first position reached via the first signal pressure and a second position reached via a biasing force of a biasing member.

Abstract: The present disclosure relates to a method for controlling a lock-up clutch of an automatic transmission. The method includes: a detecting step of detecting, by a controller, a current signal applied to a solenoid valve of an engaging element when a gear change operation begins; and a first increasing control step of controlling, by the controller, an amount of current that is applied to a solenoid valve of a lock-up clutch during an initial fill time period when it is determined that the current signal is applied to the solenoid valve of the engaging element. In particular, the solenoid valve of the engaging element is used to form a gear stage, and the controller increases the amount of current to a predetermined level for a predetermined period of time.

Abstract: A braking reduction and transmission control system is implemented in a vehicle or machine having a power source and an automatic transmission connected by a torque converter providing a fluid coupling between a power source output shaft and a transmission input shaft. A lock-up clutch operatively connect to the torque converter is locked when the shafts are rotating at approximately the same speed. The braking reduction and transmission control system unlocks the lock-up clutch when operating conditions of the machine indicate that a transmission downshift will occur, such as when a combination of a brake input device displacement and a machine ground speed compared to a transmission downshift schedule indicate that the downshift will occur. Prior to downshifting the transmission and unlocking the torque converter, the drivetrain assists the service brakes in slowing the machine.

Abstract: A multi-speed automatic vehicle transmission has an electronic control unit which permits multiple downshifts if certain conditions are satisfied. Such downshifts are direct and omit engagement and disengagement of one or more intermediate speed ratios. Multiple downshifting may allow the actual speed ratio to better match the ideal speed ratio, for example under heavy braking.

Abstract: A transmission external bump stimulation system includes a transmission of an automobile vehicle selectively operating in a mode allowing direct vehicle operator transmission gear shifts. At least one vehicle seat is positioned in the automobile vehicle supporting a vehicle operator during operation of the automobile vehicle. A shaker device is positioned in direct contact with the seat. The shaker device produces a shock wave defining an individual pulse of mechanical energy during a gear shift of the transmission initiated by the operator during operation in the mode. The shock wave is directed toward the operator.

Abstract: A transmission arrangement includes a hydrostatic transmission in which a hydrostatic unit functioning as a pump is hydraulically connected to a hydrostatic unit functioning as a motor in order to transfer drive power. The arrangement is configured with structure for damping hydraulic pressure fluctuations. The structure is assigned to a hydraulic line connecting at least one of the hydrostatic units.

Abstract: A method and system for controlling a ratio of a continuously variable transmission coupling a prime mover to a driven member in a vehicle. The method includes determining a current ratio of the continuously variable transmission, determining a projected ratio from a first ratio path of a predetermined ratio map, calculating a gradient between the current ratio and the projected ratio, determining whether the calculated gradient satisfies a gradient constraint, setting a control ratio to the projected ratio if the calculated gradient satisfies the gradient constraint, setting a control ratio to a modified ratio if the calculated gradient does not satisfy the gradient constraint, the modified ratio being based upon a ratio that satisfies the gradient constraint, and controlling the ratio of the continuously variable transmission to the control ratio.

Abstract: A hydraulic control device includes an oil pump for generating a hydraulic pressure by being rotated by power of a driving force source, a driving force source stopping unit that stops rotation of the driving force source when a predetermined condition holds, and a cut-off unit that cuts off transmission of the power from the driving force source to the oil pump when the driving force source rotates in a reverse direction as the rotation of the driving force source is stopped by the driving force source stopping unit.

Abstract: An automatic transmission including a clutch that can engage rotation transmission of two rotary members by supplying an engagement pressure to an engagement hydraulic oil chamber disposed on an outer peripheral side of a central shaft to press and move a piston member to one axial side, and disengage the rotation transmission of the two rotary members with an other-side pressing mechanism that presses and drives the piston member to the other axial side.

Abstract: A park lock apparatus and control unit for a vehicle, the apparatus comprising: a locking member (28, 30; 50) having: a first state arranged to permit independent rotational movement of front and rear drive shafts (20, 22) of the vehicle relative to a fixed position on the vehicle; a second state arranged to prevent independent rotational movement of the front and rear drive shafts of the vehicle relative to the fixed position on the vehicle; and a third state arranged to prevent rotational movement of the front and rear drive shafts of the vehicle relative to the fixed position on the vehicle, and an actuation member (36; 64) for moving the locking member between the first, second and third states.

Abstract: This control device for a vehicle switches a shift range of an automatic transmission through the use of an actuator, wherein the control device for a vehicle is characterized in being provided with a shift selection unit for receiving a shift position selection from a driver and a control unit for switching the shift range to a parking range through the use of an actuator when a vehicle power source turns off or when a drive power source stops, the control unit maintaining a neutral range, when the vehicle power source turns off or when the drive power source stops, until the elapse of a first prescribed time after the shift selection unit receives a neutral position selection while the vehicle power source is on or while the drive power source is driving.

Abstract: A sensor system, for sensing at least one property of a measured gas in a measured-gas space, includes a probe for sensing the property of the measured gas. The probe has at least one sensor element and at least one housing surrounding the sensor element. The housing is configured so that the sensor element in the housing is capable of being impinged upon with the measured gas. The sensor system also includes a receiving element connectable to a wall of the measured-gas space. The probe is introducible along an insertion axis into the receiving element and securable in the receiving element. The probe is capable of being sealed off from the measured-gas space by at least one seal. The seal encompasses at least one linear seal.

Abstract: A crankshaft seal flange has a support made at least partially of a plastic material. The support has a passage with an inner wall. The support has at least one dynamic seal that extends about a circumference of the inner wall of the passage. At least one sensor is provided that detects crankshaft rotary speed and crankshaft position. The at least one sensor encompasses an electronic component group that is integrated into the plastic material of the support.

Abstract: A rotary machine (100) includes a rotor (5) that rotates about an axis, a seal housing (30) that is disposed so as to face an outer peripheral surface of the rotor (5), and a seal body (10) that includes a plurality of thin plates (20) extending inward from the seal housing (30) in a radial direction and laminated in a circumferential direction. One thin plate (20) of the plurality of thin plates (20) has a shape in which the thin plate comes into contact with the other thin plates (20) provided on front and rear sides in a rotational direction in a state in which the thin plate does not come into contact with the rotor (5).

Abstract: A seal assembly includes first and second generally annular seals disposable about the shaft so as to be spaced apart axially along the shaft central axis. Each seal has an inner circumferential sealing surface and inner and outer axial sides, each inner axial side facing the other seal inner axial side. The first seal has at one or more coupling pockets extending inwardly from the first seal inner axial side and the second seal has one or more retaining pockets extending inwardly from the second seal inner axial side, each retaining pocket being aligned with one coupling pocket. One or more biasing members each have a first end disposed within one coupling pocket and an opposing, second end disposed within one retaining pocket, the biasing member being configured to exert an axial biasing force on each one of the first and second seals.

Abstract: In an embodiment, a mechanical seal includes: a bellows 10 sealing between a rotating-side seal ring 5 biased in the axial direction, and an outer periphery face of a rotational shaft 2; a case 11 fitted to the ring 5 and the outer periphery of the bellows 10; and a drive ring 12 tightening the bellows 10 to the shaft 2, wherein cutout grooves 5b running through in the axial direction are provided on the outer periphery area of the ring 5; detent cutout areas 5d are provided on the side face of the ring 5 on a sealing face S side in a manner extending in the circumferential direction from the cutout grooves 5b; and detent convex areas 11e are provided at the edge area of the case 11 on the ring 5 side in a manner facing the cutout grooves 5b and bulging in the inner-diameter direction.

Abstract: In an assembly method of a magnetic fluid seal (100) that includes a magnetic field forming member (130) divided in a circumferential direction, a magnetic pole member (120) including a pair of magnetic fluid retaining portions (121, 122) and a coupling portion (123) that couples them, a first bearing (160) and a second bearing (170), a step of fixing the first bearing (160) to a shaft (400) in a state in which the shaft (400) is directed in a vertical direction, a step of attaching the magnetic pole member (120) from above the first bearing (160), a step of fixing the second bearing (170) to the shaft (400) from above the magnetic pole member (120) to thereby fix the magnetic pole member (120) in a state in which the magnetic pole member (120) is positioned with respect to the shaft (400); and a step of attaching the magnetic field forming member (130) between the pair of magnetic fluid retaining portions (121, 122) are performed in order.

Abstract: A double eccentric valve includes: a drive mechanism which produces drive force for rotating a rotary shaft in a direction to open the valve; a drive force receiving unit provided integrally with the rotary shaft to receive the drive force; a bearing located between a valve element and the drive force receiving unit along the center axis of the rotary shaft to support the rotary shaft; and a return spring which produces return spring force for rotating the rotary shaft in a valve closing direction. The double eccentric valve is configured to generate a separating-direction biasing force which inclines the rotary shaft with the bearing at a fulcrum to bias the valve assembly away from a valve seat, the force being caused by the return spring force when the drive mechanism is not operated and acting in a direction perpendicular to the center axis of the bearing.

Abstract: A valve having an over-travel spring that does not necessarily need an excessively additional force to further close the valve once its valve seal comes into contact with a valve seat. The feature may be achieved by inserting an over-travel spring between a plate or stop attached to a valve stem, and a valve seal. The valve seal may come in contact with a valve seat when the valve is closed with movement of the valve stem. The valve stem may continue to travel after contact between the valve seal and the valve seat without additional force, other than that added by compressing the over-travel spring, and with a proof-of-closure sensor indicating valve closure. The valve stem may be moved in either direction for closing and opening the valve with an assist, such as a solenoid or other mechanism.

Abstract: There is disclosed a fuel tank valve assembly 24 for a fuel tank 4. The fuel tank valve assembly comprises a discharge valve 30 which in normal operation is closed, and which can be opened to discharge fluid from the fuel tank; and a water passageway 56 across which extends a membrane 60 which is permeable to water but impermeable to fuel. There is also disclosed a fuel tank 4 comprising a fuel tank valve assembly 24.

Abstract: Provided is a refrigeration valve having a valve body having an inlet, an outlet, and a flow passage defined therebetween, an expansion valve in the flow passage, a first hand valve between the inlet and the expansion valve, and a second hand valve between the outlet and the expansion valve. The first and second hand valves are provided at a top of the valve body and are movable in a first direction for preventing fluid flow through the flow passage. By providing the first and second hand valves at the top of the valve body rather than at a bottom of the valve body, valve life is increased and the valves are not prevented from operating due to particulate build up in the valves.

Abstract: A pressure compensation valve for a dialysis machine is disclosed. The pressure compensation valve has a valve housing, in which a flow path with fresh dialysate is separated from a flow path with exhausted dialysate by a diaphragm. The diaphragm and the valve housing are configured such that pressure compensation is possible. In addition, the diaphragm is configured such that no vibrations or a reduced amount of vibrations and/or no noise emission or a reduced amount of noise emission will occur during operation. Furthermore, a dialysis machine comprising such a pressure compensation valve is disclosed. The dialysis machine comprises a balancing unit, and the pressure compensation valve is arranged on the outlet side of the balancing unit.

Abstract: Arrangements of a flow path to achieve a series circuit, a regeneration circuit and a float/passive regeneration circuit. For example, a valve body having a spool bore, a valve inlet, a plurality of cavities opening into the spool bore and a spool disposed in the spool bore. A first cavity fluidly connected to a tank passage, a second cavity fluidly connected to a first work port, a third cavity fluidly connected to an inlet of another valve, a fourth cavity fluidly connected to a second work port, a fifth cavity fluidly connected to the valve inlet, a sixth cavity fluidly connected to the first work port, a seventh cavity, an eighth cavity fluidly connected to the valve inlet, a ninth cavity fluidly connected to the inlet of the other valve and a tenth cavity fluidly connected to the valve inlet.

Abstract: The improved servovalve broadly (20) includes: a body (21) having an axis of elongation (y-y), a portion of the body defining a cylinder (43) having an axis (x-x) substantially perpendicular to the body axis; a valve member (44) movably mounted in the cylinder, and adapted to be moved off-null in either direction along the cylinder axis to selectively meter the flows of fluid between a plurality of ports defined between the spool and cylinder; a rotor (58) mounted on the body for rotation about the body axis; a motor (69) acting between the body and rotor, and selectively operable to cause the rotor to rotate in a desired angular direction relative to the body; and a quill-like transfer member (64) acting between the rotor and valve spool.

Abstract: A valve assembly includes a valve body having at least a first bore and a second bore, a flow passage connecting the first bore to the second bore, a plurality of ports opening to each bore respectively, the first bore being upstream of the second bore. First and second spools are disposed in the first and second bores, respectively, for controlling the flow of fluid to and from the respective ports. A check valve is disposed in the flow passage and configured to prevent fluid flow from the second spool towards the first spool through the flow passage while allowing fluid flow from one of the ports in the first bore towards the second spool through the flow passage.

Abstract: A multi-way valve includes an outer casing provided with an internal cavity, at least one input to the cavity, at least one output from the cavity, the at least one input having sealing means, and an actuator adapted to cause the opening of the sealing means of the inputs. A cross-section of the actuator is smaller than a cross-section of the inner cavity.

Abstract: A modular manifold assembly is configured to connect to a manifold block of an auto cascade system used to fill an individual fluid tank. The modular manifold assembly may include a main housing that contains one or more sequence valves and fluid conduits. The sequence valve(s) are configured to allow fluid to be sequentially drawn from a plurality of fluid storage cylinders.

Abstract: A flat spring (70) of a solenoid valve has: an engaging claw (75) which is engaged with an engaging protrusion provided on a movable iron core, and a supporting portion (71) which is installed and fixed between a valve housing and a bobbin. The supporting portion (71) is provided with an attaching claw (72); the attaching claw (72) is attached to an attaching claw holder provided on the bobbin. The engaging claw (75) is provided on a leading end of a pulling portion (73), and a connected portion (74) connects a base end of the pulling portion (73) with the supporting portion (71).

Abstract: A setting/operating device for operating a valve stem of a regulating valve, including: a sun gear that rotates upon reception of a rotational force from a drive motor; a fixed internal gear fixedly disposed to surround the sun gear and having teeth on an inner peripheral surface; a plurality of planetary gears disposed between the sun gear and the fixed internal gear that rotate in engagement with the sun gear and the fixed internal gear while revolving around the sun gear; a movable internal gear rotatably disposed coaxially with the fixed internal gear, having teeth that engage the planetary gear on an inner peripheral surface; and an output shaft coupled to the movable internal gear and configured to rotate the valve stem of the regulating valve, wherein the planetary gears have a torque limit structure that restricts power transmission when a torque exceeding a certain level is applied.

Abstract: A high speed, fail-safe device for an electric actuator that can be independently triggered in the event of an emergency shutdown is provided. An electromagnetic brake is attached to the roller nut of the screw actuator. When actuated, the brake prevents rotation of the roller nut, and therefore enables linear movement of the roller nut upon rotation of the lead screw to linearly move an output shaft to actuate the valve. During actuation a return spring is compressed to enable retraction of the output shaft upon system failure. During such failure, the electric break is de-energized, which allows the roller nut to rotate and linearly move under force of the return spring to retract the output shaft to its fail-safe condition. A soft-stop/over-travel system is provided to limit the impact loads on the lead screw.

Abstract: The solenoid valve (10) has a poppet valve (41) which is operated to move between a position to close a port and a position to open the port. A fixed iron core (50) having a supporting leg (52) and a driving leg (51) is installed in a valve housing (11), and a movable iron core (60) which drives the poppet valve (41) is disposed between a valve driving member (42) and the fixed iron core (50). An arcuate sliding contact surface (61) is provided on one end portion of the movable iron core (60), and a sliding-abutting surface (62) which abuts on the sliding contact surface (61) is provided on a leading end portion of the supporting leg (52). When a coil (56) is de-energized, the sliding-contacting surface (61) is pressed onto the sliding-abutting surface (62) by a flat spring (70), with an abutting portion of the valve driving member (42) serving as a fulcrum of a tensile force applied to the movable iron core (60).

Abstract: A solenoid valve (10) has a U-shaped fixed iron core (50) with a driving leg (51), a supporting leg (52), and a yoke portion (53) integrally formed. One end portion of a movable iron core (60) which drives a poppet valve (41) abuts on the supporting leg (52), and the other end portion of the movable iron core (60) abuts on the driving leg (51). A sealing member (81) is disposed between and a valve housing (11) and a fixed flange (58) of a bobbin (54) attached to the fixed iron core (50). A sealing member (83) is disposed between an abutting flange (57) of the bobbin (54) and the yoke portion (53).

Abstract: An dual acting solenoid valve (DASV) is a device for controlling mediums as gases or fluids through two valves simultaneously using a dual position latching solenoid operated with a bi-stable permanent magnet activation system (BSPMAS) to allow the DASV to be electrically energy efficient and power versatile.

Abstract: An actuator includes a housing with a first end, a second end opposite the first end, and a bore disposed therein. The bore defines a poppet movement axis and extends between the first end and second end of the housing. A solenoid is disposed within the bore and extends about the poppet movement axis. An armature is disposed within the bore and is movable along the poppet movement axis between a disengaged position and an engaged position, the engaged position proximate the solenoid and the disengaged position spaced apart from the solenoid. A magnet is disposed within the bore between the first end of the housing and the armature, the magnet magnetically coupled to the armature to bias the armature towards the disengaged position.

Abstract: A control device (1) for a stopper (3) comprises: —an outer casing (10), —a control rod (6) sliding through the casing (10), rigidly attachable to the stopper (3), —a hydraulic circuit (20) including a double-acting hydraulic cylinder (21) and a reversible hydraulic pump (9), the hydraulic cylinder (21) having a first and a second chamber (21a, b) between which a piston (22) slides, the hydraulic pump (9) being connected directly to the first and second chamber (21a, b) by means of a first branch and a second branch (20a, b) of said hydraulic circuit (20, respectively, the piston being rigidly attached to the control rod (6), the hydraulic circuit (20) being entirely housed in the outer casing (10), —a control circuit (30) connected to the hydraulic circuit (20) to control the position of the piston (22).

Abstract: An adjustment system for a rotary valve having a drive wheel with drive wheel teeth that can turn about a first axis of rotation to drive a driven wheel with driven wheel teeth that can turn about a second axis of rotation that is substantially parallel to the first axis of rotation. The teeth extend in each case around only part of the circumference of the respective wheel. The driven wheel can be adjusted by the turning of the drive wheel from a first rotational position, in which the teeth are mutually engaged, into a locking position, in which the driven wheel is held in place when the drive wheel turns further. A rotary valve with such an adjustment system is also described.

Abstract: A throttle valve 10 continuously increases/decreases the flow rate of air flowing through a communication hole 17 through which a first port 11 and a second port 12 are communicated with each other, by using a throttle valve element 22. A valve seat member 15 having the communication hole 17 is attached to a housing 13. An electric motor 25 is attached to a motor housing hole 24 formed in the housing 13. The throttle valve element 22 is driven in an axial direction by a motor shaft 28 of the electric motor 25. A gap between the motor housing hole 24 and the electric motor 25 is sealed by a fixed sealing member 41 having a large diameter, and the motor shaft 28 is sealed by a rotary sealing member 42 having a small diameter, whereby the throttle valve element can be driven by the electric motor having a small output.

Abstract: Bypass check valves, suitable for bypassing a Venturi gap, are disclosed and include a housing defining an internal cavity having a first seat and a second seat, and a seal member within the internal cavity translatable between a closed position against the first seat and an open position against the second seat. The second seat defines a support structure having a middle region of a predetermine height and a downstream side having a height that is shorter than the predetermined height of the middle region. The seal member is seatable against the second seat with a downstream portion thereof a further distance from the first seat than an upstream portion thereof.

Abstract: Methods, apparatus, and systems providing enhanced feed rate control of tubing and conduit feeds by a powered feeder to an in-ground placement device moved across the ground by a steerable vehicle. In one aspect, ground speed of the vehicle is sensed. Feed motor speed is correlated to length of tubing or conduit estimated to be fed per feed wheel revolution by the feed motor. A controller adjusts feed motor speed to match ground speed to feed rate. In another aspect, instead of estimating feed rate by feed wheel rotation, actual speed of movement of the tubing or conduit is sensed. Feed motor speed is automatically and dynamically adjusted to match ground speed to tubing or conduit speed. In either embodiment, sensing of ground speed can be used to sense starting and stopping of the vehicle. This can be used to turn the feed motor on or off. In either embodiment, integration with a precision agriculture intelligent controller can allow operator control right from the precision ag display.

Abstract: In general, a conductor removal system 1 comprises a conductor sectioning tower which can be used to automate lifting and landing of various conductor sections. In most embodiments, the conductor sectioning tower can selectively and controllably go between an initially compact position to a raised, substantially vertical position with respect to the conductor removal system's transport frame. Conductors are cut creating a severed conductor section which can be positioned onto a conductor landing cart for further removal processing.

Abstract: A system configured to handle reels for laying elongated members on the bed of a body of water, and in particular for transferring reels between an auxiliary structure and a laying vessel, has a bridge configured to connect the auxiliary structure and the laying vessel; and actuators configured to move a reel along and resting on the bridge.

Abstract: The present disclosure relates to an arrangement for fastening a flexible tube, in particular a corrugated tube, to an article, in particular to a component of a vehicle. The arrangement comprises a flexible tube, which is placed on the article; a covering element, as anti-squeeze protection for the flexible tube, the covering element being supported on the article on both sides of the flexible tube and covering at least a portion of the flexible tube in an arcuate manner; and a band clamp, which is guided around an outer side of the covering element and around a side of the article that faces away from the flexible tube.

Abstract: Disclosed is roller assembly comprising: a base; a shaft mounted on the base, the shaft defining an axis; a pedestal comprising a first arm and a second arm, the first arm and the second arm positioned on the shaft, the pedestal movable axially relative to the shaft; and a roller rotatably positioned on the shaft between the first arm and the second arm of the pedestal, the roller movable axially relative to the shaft.

Abstract: A high-pressure tube comprises several co-extruded layers which include a reinforcing inner layer. Said reinforcing inner layer exhibits a mixture of a block copolymer and a homopolymer. As a result, a high-pressure tube is obtained the bending stiffness of which is reduced.

Abstract: A hose monitoring system and a method of monitoring a hose are disclosed. A system includes a hose assembly including a hose having a first conductive layer and a second conductive layer, and a monitoring circuit in electrical communication with the first and second conductive layers. The system also includes an energy harvesting unit in electrical communication with the monitoring circuit, the energy harvesting unit including one or more energy harvesters for providing electrical energy to the monitoring circuit.

Abstract: A pipe element is formed of a metal pipe and at least one metal connector, fastened to an end of the metal pipe such that torques and axial forces can be transmitted between the metal pipe and the metal connector. The metal connector has thread, in particular a conical thread, or a flange, by way of which the metal connector can be screwed to another metal connector of an additional pipe element in order to connect two pipe elements. The metal connector is screwed to an inner sleeve by way of a cylindrical thread so that the metal pipe is a really clamped between the metal connector on the outside and the inner sleeve on the inside in a connection region. The connection region is conically tapered toward the pipe end.

Abstract: Fittings, including elbow fittings and Tee fittings have bodies that surround a central space and define openings to receive pipe elements. Ribs surround the openings, and gaps are positioned between the ribs to permit deformation of the body when ends of the body in facing relation are brought together. The body may be formed of two housings or unitary in construction. The ribs may be grooved to accommodate toothed retainer rings providing mechanical engagement with pipe elements. The ribs have surfaces with radii of curvature that, when the ribs are undeformed, are substantially equal to the radii of curvature of the pipe elements they engage.