Abstract: A forward facing rear door assembly for a motor vehicle includes a forward facing rear door having a forward end and a rear end. The forward facing rear door assembly also includes a single hinge connected to the rear end of the forward facing rear door and for connection to a “C” pillar of a vehicle body to allow a forward end of the rear door to open and close a door opening in the vehicle body.

Abstract: A door hinge mounting structure for vehicles comprises a bracket having a closed cross-section. A coupling nut is coupled to the bracket via a plurality of flanges and a coupling bolt. The coupling bolt also has a guide portion, such that an easy assembly allows a door hinge to be securely and stably coupled to a door, thereby reducing maintenance of the door hinge assembly and providing a firm support for the door to the vehicle body.

Abstract: An automotive closure panel which is rotatable about a pivot axis has an axial locator insert situated within a pivot bearing insert bore to set a margin extending between the closure panel and a vehicle body. This system is particularly useful for closure panels such as tailgates having torsion bar or motorized lift assist, because such systems are not easily disassembled for the purpose of setting the closure panel margins.

Abstract: An automotive vehicle has a door adapted to pivot about a generally horizontal pivot axis, with the door including a shell defining a space surrounded by the shell. The door is pivoted upon bearings located at each end of the door. A full floating torsion bar is provided and includes a first end rotationally grounded to the door shell and a second end engaged with and rotationally locked with a bearing inserts so that the torsion bar will be subjected to torsional loading as the door is pivoted. At least a portion of the torsion bar extends along an external recess defined by the door's inner and outer panels.

Abstract: A method and motor vehicle door attachment system that automatically disengages the hinges on the doors on a motor vehicle, in order to provide immediate access to occupants by medical and rescue personnel, that also provides extra room for rescue efforts by the medical personnel. System includes electronic sensor that unlocks an intermediate member onto which the hinges on a door are attached. During an accident the intermediate members are unlocked from the motor vehicle and thereby allow the doors along with the hinges to be removed from the vehicle. A system that enables immediate and secure removal of the doors along with the hinges from a motor vehicle is presented as what is new in the art.

Abstract: An apparatus for. A slide mechanism for a door and structural member assembly, the slide mechanism including a frame, a door carrier movably secured to the frame, a door and structural member such as a B-pillar at least partially supported by the door carrier, a slide mechanism that permits the B-pillar and the door to be moved along the door carrier without detaching from the vehicle frame.

Abstract: An automotive vehicle has a door adapted to pivot about a generally horizontal pivot axis, with the door including a shell defining a space surrounded by the shell. The door is pivoted upon bearings located at each end of the door. A torsion bar lift assist is provided with a vibration and noise isolator and damper, which is engaged about a central portion of the torsion bar. The damper prevents objectionable noise which could otherwise result in the event that the torsion bar strikes the shell of the door because of road-induced vibration.

Abstract: A hinge mechanism having first and second pivot shafts held by first and second hinge base members, respectively, which also connect to ends of a hinge arm member. First and second cams on the first and second hinge base members engage first and second control levers on the ends of the hinge arm members. First and second cam portions are provided by the opposed ends of the hinge arm member respectively and engage first and second pivotable check plates. First and second follower members are mounted on the first and second check plates respectively and contactable with the first and second cam portions respectively. First and second springs bias the first and second check plates in a direction to press the first and second follower members on the first and second cam portions respectively. A third spring biases a link member toward the first hinge base member.

Abstract: An automotive vehicle has a door adapted to pivot about a generally horizontal pivot axis, with the door including a shell defining a space surrounded by the shell. The door is pivoted upon bearings located at each end of the door. A torsion bar lift assist is provided with a vibration and noise isolator and damper, which is engaged about a central portion of the torsion bar. The damper prevents objectionable noise which could otherwise result in the event that the torsion bar strikes the shell of the door because of road-induced vibration.

Abstract: An apparatus for attaching a door to a passenger vehicle body having a lift arm and a hinge assembly. The lift arm rotatably connects the door to the vehicle body. The lift arm imparts upward rotational movement to the door relative to the vehicle body as upward pressure is applied to the arm. The hinge assembly allows the door to open horizontally about a pair of hinges connected to the hinge assembly. A stop pin assembly dictates whether the door can be opened vertically or horizontally.

Abstract: A C-pillar assembly for a vehicle that lacks a B-pillar, the C-pillar assembly including an inner reinforcement member, an outer reinforcement member, upper and lower hinge assemblies, and an outer garnish member. The outer reinforcement member is disposed over the inner reinforcement member. The inner and outer reinforcement members are secured to one another so as to define a C-pillar having, in cross section, a generally box-like shape. The outer reinforcement has an upper mounting location to which the upper hinge assembly is secured and a lower mounting location to which the lower hinge assembly is secured. A portion of the lower hinge assembly is disposed within a hinge pocket formed in the outer reinforcement member. The outer garnish member is secured to the outer reinforcement member and defines a slotted opening through which the lower hinge assembly extends.

Abstract: A motor vehicle has an opening which can be closed by a swivellable component, particularly a tail gate, the component being mounted by at least one hinge on a vehicle body part and the hinge having a first hinge half fastened to the vehicle body part and a second hinge half fastened to the swivellable component. An adjusting device for aligning the swivellable component with respect to the adjoining vehicle body contour is provided. So that the aligning of the swivellable component can be carried out from the direction of the exterior side of the vehicle when the component is closed, the adjusting device is arranged on the exterior side on the end area of the second hinge half facing the swivellable component.

Abstract: A retrofit vehicle door lift conversion kit adapted for lifting a vehicle door vertically that fits as a conversion kit replacing factory door hinges on a variety of different types of existing vehicles. A door attaching arm is mounted to a fixed chassis plate by a double axis connector for horizontal and vertical motion. A lift assisting actuator, which may be a vehicle specific pressure adjustable gas pressure spring, pivotally mounted between the plate and the arm, assists in lifting the door vertically. Replaceable vehicle specific plates mount to the fixed chassis plate. A replaceable vehicle specific arm and door attaching brackets mount to the door attaching arm. A horizontal limiter, a mechanical vertical height limit adjustment device, a vertical lift adjustment, and a safety lock for maintaining the door in the up position are adjustable for specific vehicles.

Abstract: A door for the operator's cab on an agricultural tractor is formed from a frameless single pane of transparent material pivoted at one edge on a pillar of the tractor. The pivot is formed of two hinges affixed to the pane and a reinforcing member extending generally parallel to the pivot axis and interconnecting the wings of the hinges that are affixed to the pane. The reinforcing member is arranged in line with the pillar on which the door is mounted, when viewed from the position of the driver of the vehicle, so as to minimize obstruction of the field of view of the driver. In another aspect of the invention, the surfaces on the hinges that mate with the pane are machined to match the contours of the pane while the reinforcing member and the hinges are in one piece.

Abstract: A rear closure assembly for use with a vehicle includes a door having first and second handles for pivoting the door about first and second vertical pivot axes. Latches on the door are engageable with strikers on the vehicle. The latches and strikers form the first and second vertical pivot axes. The latches are disengageable by the handles to selectively pivot the door about one of the vertical pivot axes.

Abstract: A cabin equipped with link type door comprises two links provided on at least upper parts of both a cabin and an opening and closing door at the side of the cabin, one-side ends thereof being pivotally supported on the door and the other ends on the cabin, so that the door is retained on the cabin by the links; a movable supporter for supporting the door weight, which is provided in the middle part of the link for mainly supporting the door weight of the links; and a support member for placing the movable supporter to support the door weight and making the movable supporter travel in the opening and closing movement of the door, which is provided on the cabin, whereby the sagging of the links can be prevented to keep the link pivotal support part from shaking.

Abstract: A vehicle power window and power door lock system includes a vehicle pillar adapted for use between openable and closable vehicle doors and a single lock actuation assembly in the pillar adapted for engagement with a front door lock latch assembly on a front door and a rear door lock latch assembly on a rear door for locking and unlocking the doors. The vehicle power window and power door lock system further includes a single reversible electric motor in the pillar adapted for selective engagement with a front window on an adjacent front door and a rear window on an adjacent rear door for driving the windows up and down. A vehicle side door assembly includes a door lock latch assembly, a latch rod operatively connected to the latch assembly, a window, and a driven gear operatively connected to the window. The latch rod is operably connectable to a lock actuation assembly located in a body pillar adjacent to the door when the door is positioned against the body pillar.

Abstract: The invention provides a vehicle door assembly including two entrances. Both entrances are surrounded by a frame assembly for mounting on the vehicle. One of the entrances is at about the height of the vehicle floor, while the other is lower than the vehicle floor and opens into a stairwell that leads up and into the vehicle. The floor-level door may be suitable for use with an appliance for assisting passengers to enter the vehicle, such as a lift or a ramp. The door assembly includes doors for closing the entrances. The door assembly may be mass-produced as a modular component and mounted on a conventional vehicle that has been specially modified to accept the door assembly.

Abstract: An automotive vehicle, such as a pickup truck, has a tailgate including a door adapted to pivot about a generally horizontal pivot axis, with the door including a shell defining a space surrounded by the shell. The door is pivoted upon bearings mounted upon bearing retainers located at each end of the door. A full floating torsion bar is provided and includes a first end rotationally grounded within the interior space of the door shell and a second end engaged with and rotationally locked with one of the bearing inserts so that the torsion bar will be subjected to torsional loading as the door is pivoted. Because of the full floating feature, the hinge function of the tailgate will not be impaired in the event that the torsion bar becomes fractured.

Abstract: The invention provides a door assembly for a motor vehicle. The motor vehicle includes a body portion including at least one aperture formed therein. The door assembly includes a door moveable between a closed position substantially covering the aperture and an open position substantially clearing the aperture. At least one hinge assembly is provided including a substantially elongated lever with first and second pivots. The first pivot is operably attached to the door and the second pivot is operably attached to the vehicle. The lever and the first and second pivots provide an arcuate path movement of the door lengthwise of the vehicle.

Abstract: A hinge assembly for truck utility bodies. The hinge assembly comprising three female hinges, a male hinge, and a hinge pin aligned along the pivot axis of door of the truck utility body. The hinge assembly is mounted inside the utility body of the truck, thereby eliminating the problems associated with externally mounted hinge assemblies.

Abstract: One large opening (1) formed in a car body side portion and continuous in a back-and-forth direction is opened and closed by front and rear side doors (11, 12). When the side doors (11, 12) are closed, a lap portion (15) is formed where a rear end of the front side door (11) overlaps a front end of the rear side door (12) externally in a direction of car width. A reinforcing member (25) extending in a vertical direction is disposed on the rear side door (12) in the vicinity of the lap portion (15). The rear end of a front impact bar (27) disposed in the front side door (11) extends to the lap portion (15). The front end of a rear impact bar (26) disposed in the rear side door (12) is connected to the reinforcing member (25).

Abstract: An automotive tailgate includes a door adapted to pivot about a generally horizontal pivot axis, with the door including a shell defining an interior space. The door is pivoted upon bearings mounted upon bearing retainers located at each end of the door. A full floating torsion bar is provided and includes a first end rotationally grounded within the interior of the door shell and a second end engaged with and rotationally locked with one of the bearing inserts so that the torsion bar will be subjected to torsional loading as the door is pivoted. Because the torsion bar is full floating, the operation of the tailgate hinges will not be impaired even if the torsion bar were to become fractured.

Abstract: A hinge cup is adapted to be installed on an outer surface of a vehicle end gate. The hinge cup includes a hinge cup body constructed of a polymer material. The hinge cup body is attached to a surface of the vehicle end gate and has an outer surface that is operable to cooperate with a trunnion member extending outwardly from an end gate mounting location on a vehicle body. The hinge cup body cooperates with the trunnion member when the end gate is placed adjacent the end gate mounting location on the vehicle body.

Abstract: A decklid hinge is provided for a rear compartment of a vehicle. The decklid hinge includes a body side strap adapted to be connected to a vehicle body of the vehicle. The decklid hinge also includes a decklid side strap adapted to be connected to a decklid for closing a recess of the rear compartment. The decklid hinge includes a first link interconnecting the body side strap and the decklid strap for allowing rotation therebetween. The decklid hinge further includes a second link interconnecting the body side strap and the decklid strap for guiding pivoting action of the hinge along a predefined path. The decklid hinge includes a primary spring interconnecting the body side strap and the decklid strap to counterbalance a weight of the decklid when opening. The decklid hinge further includes a free-rise mechanism to allow the decklid to free-rise from a partial open position to a full open position.

Abstract: A hinge for pivotally mounting a first door to a door pillar of a vehicle body of a vehicle. The hinge having been provided thereon one portion of a co-operating latching arrangement for releasably securing in a closed position a second door.

Abstract: In a check plate supporting structure, a check plate of a door checker interposed between a door support and a door supported on the door support is turnably supported on a bracket mounted to the door support. A pivot secured to the bracket is relatively turnably press-fitted into a polygonal bearing bore defined in the check plate. Large numbers of pressure-contact portions and gaps are alternately arranged between an inner peripheral surface of the bearing bore and an outer peripheral surface of the pivot in circumferential directions thereof. Thus, the looseness between the pivot secured to the bracket and the bearing bore in the check plate can be eliminated without excessive increase in turning torque of the check plate relative to the bracket, thereby preventing generation of an abnormal sound during opening and closing of the door and facilitating manual mounting of the door checker to the door support.

Abstract: The vehicular door hinge of the present invention facilitates both forward and rearward swinging door motion. The present invention achieves this objective by reversing the orientation of the door component portion of the hinge within the body component portion of the hinge. An integrated door stop is incorporated into the body component. The integrated door stop further includes non-parallel stop surfaces that abut the door component's geometry in both the conventional and reversed configurations to give the desired opening angles. As a result, the present invention allows for different uses from the same components where a first predetermined angle may be achieved or a second predetermined angle may be achieved with different swing directions.

Abstract: An automotive hinge facilitates substantially rotary motion of a closure panel relative to a fixed body structure by means of a single resilient member configured to carry all required structural and operational loadings.

Abstract: A seat belt system for a vehicle, for restraining an occupant in a seat disposed in a compartment of the vehicle. The vehicle comprises an opening formed on at least one side of the vehicular body, and a first door moving between a first state where the first door closes at least a part of the opening and a second state where the first door opens the opening. The seat belt system includes a belt webbing, a retractor disposed in the first door for retracting the proximal end of the belt webbing, and a sliding device fixed on a lower edge of the opening, to which the distal end of the belt webbing is attached. The sliding device permits the distal end of the belt webbing to slide along the lower edge of the opening between a forward position and a rearward position. The distal end of the belt webbing is located at the rearward position when the first door is in the second state.

Abstract: A vehicle having an occupant space within a cab is disclosed. The cab has an access door providing access to the space. The door includes a novel hinge mounting construction including a hinge mounting plate. The plate is moveable over a limited adjustment range. A hinge plate locator sized to mate with complemental surfaces of a hinge leaf is provided. The locator is connected to the plate and moveable with the plate as the plate is moved within its adjustment range. A fastener is provided to fix the locator and plate in an adjusted position such that the door may be removed and remounted without repeating an initial locating adjustment.

Abstract: Connection for a grill panel (10) of a motor vehicle, incorporating a pair of mountings for the grill panel. To provide a safe and dimensionally stable connection for the grill panel, it is proposed, inter alia, that each mounting be associated with a hinge (20; 30) for a side door of the vehicle.

Abstract: A vehicle has a chassis providing a drier compartment and includes a door frame about an opening into the driver compartment. A door is cooperatively dimensioned and configured to close the opening, and is pivotably mounted on the door on the forward portion of the door frame by a hinge. The hinge includes a pivot pin having a pivot axis angled rearwardly and outwardly. The door pivots upwardly and forwardly about the pivot pin during opening movement. Upward opening of the door is facilitated by the inclusion of a spring arragement biasing the door into an open position.

Abstract: The invention provides a vehicle door assembly including two entrances. Both entrances are surrounded by a frame assembly for mounting on the vehicle. One of the entrances is at about the height of the vehicle floor, while the other is lower than the vehicle floor and opens into a stairwell that leads up and into the vehicle. The floor-level door may be suitable for use with an appliance for assisting passengers to enter the vehicle, such as a lift or a ramp. The door assembly includes doors for closing the entrances. The door assembly may be mass-produced as a modular component and mounted on a conventional vehicle that has been specially modified to accept the door assembly.

Abstract: In a door hinge mounting structure, a retaining member having a threaded hole formed therein is provided in the interior of a door panel or a door mounting portion on a vehicle body. A positioning bolt is screwed into the threaded hole via a positioning bolt passable hole formed in the door panel or the door mounting portion. A door hinge is positioned based on the position of the positioning bolt so mounted. In the door hinge mounting structure, the positioning bolt passable hole is formed larger in diameter than the threaded hole in the retaining member. Restrictive wall portions are provided in the interior of the door panel or the door mounting portion for restricting the movement of the retaining member within a range in which the positioning bolt passable hole and the threaded hole in the retaining member substantially coincide in position with each other.

Abstract: A forward facing rear door assembly for a motor vehicle includes a forward facing rear door having a forward end and a rear end. The forward facing rear door assembly also includes a single hinge connected to the rear end of the forward facing rear door and for connection to a “C” pillar of a vehicle body to allow a forward end of the rear door to open and close a door opening in the vehicle body.

Abstract: A hatchback for an automobile has an essentially peripheral supporting frame (1) designed as a hollow metal section, with a windshield area and a wall area, with a connecting section (2) arranged transversely in the supporting frame (1) at the transition of the windshield area and wall area, with a windshield (3) mounted on the supporting frame (1) in the windshield area and with an outside door panel (4) mounted on the supporting frame (1) in the wall area, whereby hinge brackets (5) that are movable with the supporting frame (1) are mounted on the upper edge of the supporting frame (1) in the windshield area and are pivotably connectable by at least one hinge element (8) each to stationary hinge blocks (7) mounted on a stationary body part (6) when the automobile hatchback is installed.

Abstract: A method and apparatus for coupling a vehicle body panel partition for pivotal movement between an upright and a retracted position. A mounting includes hinge sets formed from two hinge leafs, each hinge leaf being used to retain one of the alternate ends of the torsion rod pin extending through aligned pivot portions on each pin leaf. Preferably, each hinge set is integrally formed with the torsion pin by retainers holding ends of the torsion pin with respect to each of the leafs. In the preferred embodiment, a return bent end of the torsion pin is received in an extended support member while the other end is retained in a returned bent portion of the second leaf, each end extending in a radial direction aligned at an angle to the direction of the other end.

Abstract: A hinge assembly is provided including a first hinge member including a first mounting structure to mount the first hinge member to one of a vehicle closure member and a vehicle body. The first hinge member includes a rotatable member. The rotatable member and the first mounting structure may be integrally formed together from a single piece of metal. The hinge assembly includes a second hinge member including a second mounting structure to mount the second hinge member to the other of the vehicle closure member and the vehicle body. The second hinge member includes a wall portion to define a rotatable member receiving space. The rotatable member receiving space is configured to rotatably receive the rotatable member for enabling the first and second hinge members to pivot relative to one another. The wall portion and the second mounting structure may be integrally formed together from a single piece of metal.

Abstract: A method and apparatus for coupling a vehicle body panel partition for pivotal movement between an upright and a retracted position. A mounting includes hinge sets formed from two hinge leafs, a hinge leaf being used to retain one of the ends of the torsion rod pin extending through aligned pivot portions on each hinge set. Preferably, each hinge set is integrally formed with the torsion pin by retainers holding ends of the torsion pin with respect to one leaf of each of the hinge sets. In the preferred embodiment, a return bent end of a common torsion pin is received in a first leaf of one of at least two hinge sets, while the other end of the rod is bent and retained in a second leaf of a second hinge set.

Abstract: A forward facing rear door assembly for a motor vehicle includes a forward facing rear door having a forward end and a rear end. The forward facing rear door assembly also includes a single hinge connected to the rear end of the forward facing rear door and for connection to a “C” pillar of a vehicle body to allow a forward end of the rear door to open and close a door opening in the vehicle body.

Abstract: A door support system for supporting a vehicle door on a vehicle body for movement in opening and closing directions includes a door hinge system and an infinite door check system. The door hinge system includes a pair of first mounting structures and a pair of second mounting structures pivotally coupled to provide for movement of the vehicle door relative to the vehicle body. The infinite door check system includes first and second one-way check devices. The first one way check device applies a biasing force to resist movement of the vehicle door in the closing direction, and the second one way check device applies a biasing force to resist movement of the vehicle door in the opening direction. Each of the check devices includes a biasing structure that provide the biasing force and a clutch that enables or disables the application of the biasing force to the vehicle door.

Abstract: A hinge assembly for a motor vehicle door with a built-in door stop includes a fixed knuckle having a first part which has a drilling allowing the fixed knuckle to be attached to the bodywork of the vehicle, and a second part perpendicular to the first part having a drilling to accommodate a pin about which the hinge pivots. The hinge assembly also includes a moving knuckle having a drilling allowing the moving knuckle to be attached to the door and having two approximately horizontal flat zones, each provided with a drilling to take the pin and each having a notched cam. The hinge assembly further includes two pressing rollers kept in contact with a cam of the moving knuckle and a spring held in the fixed knuckle and having two vertical branches inserted in the rollers and working in bending, causing the rollers to exert pressure on the cams. The pin articulates the moving knuckle to the fixed knuckle.

Abstract: The invention relates to a coupling device for joining a door stop (17) to the hinge (1, 2) of a door of a motor vehicle, especially a door stop (17) consisting of a brake element and a retaining element that is rotationally fixed to one half (1) of the hinge and a retaining housing (18) that is rotationally fixed to the other half (2) of the hinge, whereby the brake element and retaining element is formed by an engaging element with an external peripheral contour that deviates from a pure circular shape and the retaining housing (18) is formed by a hollow profiled section with at least one inner peripheral contour that marks at least one braking or retaining position. The aim of the invention is to provide a coupling device that simplifies the production of and enables the production cost of the semi-hinge and the retaining housing to be reduced, in addition to facilitating assembly of the door stop with one half of the hinge of the door of a motor vehicle.

Abstract: Door stop for motor vehicles comprising:

Abstract: In a convertible vehicle including a roof which is movable between a closed position, in which the roof covers an interior vehicle space, and an open position, in which the roof is deposited in a storage compartment behind the passenger compartment of the vehicle, that is covered by a rear lid, an operating mechanism for opening and closing the rear lid is provided which includes front and rear pivot arms pivotally mounted to the vehicle body, a coupling arm pivotally connected to the pivot arms and first and second links, each of which has one end pivotally connected to the rear lid and the first link is pivotally connected with its other end to the coupling arm while the second link forms an extension of the rear pivot arm.

Abstract: An automotive body structure includes a body (14) having a front body section (14a) defining a passenger compartment (2) and a rearbody section (14b) defining a cargo bed (4), and a division panel (6) dividing the passenger compartment (2) and the cargo bed (4) from each other. A ridge (20) prevents the direct collision of a cargo (X) accommodated in the cargo bed (4) against the division panel (6). A reinforcing member (32) restrains the division panel (6) from being bent by a moment of force applied thereto by the collision of the cargo (X) against the division panel (6). Support means (34) resiliently controls the forward movement of a predetermined part of a pivotal shaft (12) when the cargo (X) strikes against the division panel (6). The ridge (20), the reinforcing member (32) or the support means (34) of the automotive body structure protects the division panel (6) from damage.

Abstract: A door support system for supporting a vehicle door on a vehicle body for movement in opening and closing directions includes a door hinge system and an infinite door check system. The door hinge system includes a pair of first mounting structures and a pair of second mounting structures pivotally coupled to provide for movement of the vehicle door relative to the vehicle body. The infinite door check system includes first and second one-way check devices. The first one way check device applies a biasing force to resist movement of the vehicle door in the closing direction, and the second one way check device applies a biasing force to resist movement of the vehicle door in the opening direction. Each of the check devices includes a biasing structure that provide the biasing force and a clutch that enables or disables the application of the biasing force to the vehicle door.

Abstract: A door hinge is provided for a door of a vehicle. The door hinge includes a body side hinge strap adapted to be connected to a vehicle body of the vehicle. The door hinge also includes a door side hinge strap adapted to be connected to the door for closing an opening in the vehicle body. The door hinge includes a roller assembly connected to the door side hinge strap. The door hinge further includes a cam pivotally connected to the body side hinge strap and cooperable with the roller assembly, and a spring interconnecting the body side hinge strap and the door side hinge strap to act as an integral check and urge the cam into contact with the roller assembly.

Abstract: A door-stop device for vehicles having a base structure with a pair of rollers that are parallel to each other and pushed against one another. The door-stop device also includes a metal tie rod with a pair of rolling surfaces set opposite to one another where the rollers act. The rolling surfaces have a positioning notch designed to engage one of the rollers and define a position of stable retention of the door. The positioning notch includes an arched central portion with an extension extending in the direction of the longitudinal axis of the tie rod and a pair of arched lateral portions with a radius of curvature.