Hinge assembly for rotatably mounting a display to a surface

The present invention relates to an assembly for rotatably mounting a display unit to a surface for movement between a first angular position adjacent the surface, a second angular position spaced from the surface and a range of third angular positions spaced from the second angular position. A first pintle secured to a first hinge mount is rotatably connected to a first hinge bracket. A first friction element secured to the first hinge bracket imparts a first resistive friction to the first pintle. A first detent mechanism secured to the first hinge bracket releasably secures the first pintle in the second angular position and imparts a second resistive friction to the first pintle when the first pintle is rotated through the range of third angular positions. The display unit rotates in a controlled manner from the first angular position to the second angular position due to a gravitational force.

BACKGROUND OF THE INVENTION

The present invention is directed towards a hinge assembly for rotatably mounting a display unit to a surface, and more particularly, to the interior facing side of the roof of a vehicle. Even more particularly, the present invention relates to a hinge assembly for the controlled rotation of a liquid crystal display monitor releasably secured to the roof of a vehicle from a first angular position adjacent to the roof to a second angular position spaced from the roof and thereafter, for the additional rotation of the monitor to any desired positioning within a range of third angular positions, all spaced from the roof.

The efficient utilization of limited space in the interior of a vehicle is highly desirable. The recent availability and acceptance of video systems for in-vehicle use has placed an additional requirement on the competition for the limited space. A monitor that can be variably positioned for optimal viewing when in use and unobtrusively stored when not in use provides the designer of vehicle interiors with enhanced flexibility in designing the interior layout of vehicles having a video system.

One approach to providing in-vehicle video capability while still conserving interior vehicle space is to releasably secure the monitor to the roof of the vehicle. Such an approach generally requires a hinge that allows the rotation of the monitor from a closed or storage position adjacent to the roof to an open position spaced from the roof for use. The hinge should include a friction mechanism that provides sufficient restraint of unwanted movement of the monitor while still allowing the monitor to be easily positioned for optimal viewing.

In addition to video systems for in vehicle use, another common application for such a hinge is in the computer display field. Conventional pivotable computer displays are found in laptop, notebook and palm computers. It is often necessary to control the angular position of a first member such as a laptop screen, which is rotatably coupled to a second member such as a base by a hinge.

Known hinges use a torsion spring, wrap spring, coil spring or similar device to impart a resistive friction to a shaft of the hinge that is greater when the shaft is rotated in one direction than when the shaft is rotated in the opposite direction. Such a hinge is used in a laptop computer, for example, to provide a greater closing force than an opening force so that the laptop screen cannot be slammed close and thus be damaged.

Accordingly, a hinge assembly that provides for controlled rotation and angular positioning of a first member which is rotatably coupled to a second member by a hinge is highly desirable.

BRIEF SUMMARY OF THE INVENTION

One aspect of the present invention is an assembly for rotatably mounting a display unit to a surface for movement between a first angular position adjacent the surface, a second angular position spaced from the surface and a range of third angular positions spaced from the second angular position. The display unit has a display backing panel for supporting the display unit. The assembly has a first hinge bracket for being connected to the surface and a first hinge mount for being connected to the display backing panel for rotation therewith. A first pintle is secured to the first hinge mount for rotation therewith and is rotatably connected to the first hinge bracket. A first friction element is secured to the first hinge bracket and is rotatably engaged with the first pintle. The first friction element imparts a first resistive friction to the first pintle when the first pintle is rotated. A first detent mechanism is secured to the first hinge bracket and is rotatably engaged with the first pintle. The first detent mechanism releasably secures the first pintle in the second angular position and imparts a second resistive friction to the first pintle when the first pintle is rotated through the range of third angular positions. The display unit rotates in a controlled manner from the first angular position to the second angular position due to a gravitational force.

Another aspect of the invention is an assembly for rotatably mounting a display unit to a surface for movement between a first angular position adjacent the surface, a second angular position spaced from the surface and a range of third angular positions spaced from the second angular position. The display unit has a display backing panel for supporting the display unit. The assembly has a first hinge bracket for being connected to the surface. The first hinge bracket has a first arm, a second arm spaced apart from the first arm and a first stop. The assembly additionally has a first hinge mount for being connected to the display backing panel for rotation therewith. The first hinge mount has a first step cooperating with the first stop to limit the range of third angular positions. A first pintle is secured to the first hinge mount for rotation therewith. The first pintle is journaled within the first and second arms and has a first section extending from the first arm. The first section connects the first pintle to the first hinge mount. A first friction element is secured to the first hinge bracket for rotation therewith and is rotatably engaged with the first pintle. The first friction element imparts a first resistive friction to the first pintle when the first pintle is rotated. A first detent mechanism is provided. The detent mechanism includes a generally cylindrical-shaped first rocker secured to the first pintle for rotation therewith. The first rocker has a first circumferential surface having a first pair of generally opposing offset flats and a second pair of generally opposing offset arcuate surfaces. The detent mechanism additionally includes a generally U-shaped first detent spring secured between the first and second arms of the first hinge bracket for rotation therewith. The first detent spring has a first pair of lever arms engaging the first circumferential surface of the first rocker. The first pair of lever arms cooperate with the first pair of generally opposing offset flats to releasably secure the first pintle in the second angular position and further cooperate with the second pair of generally opposing offset arcuate surfaces to impart the second resistive friction to the first rocker when the first pintle is rotated through the range of third angular positions. The display unit rotates in a controlled manner from the first angular position to the second angular position due to a gravitational force, and thereafter, is further rotatable through the range of third angular positions in response to an applied force.

Still another aspect of the invention is a hinge assembly for rotatably coupling a first member to a second member for movement between a first angular position and a range of second angular positions. The hinge assembly includes a first hinge bracket for being connected to the second member and a first hinge mount for being connected to the first member for rotation therewith. A first pintle secured to and extending from the first hinge mount for rotation therewith is rotatably connected to the first hinge bracket. A first friction element is secured to the first hinge bracket. The first friction element rotatably engages the first pintle and imparts a first resistive friction to the first pintle when the first pintle is rotated in a first direction. The first friction element imparts a second resistive friction to the first pintle when the first pintle is rotated in a second direction. The second resistive friction is less than the first resistive friction. A first detent mechanism is secured to the first hinge bracket and rotatably engages the first pintle. The first detent mechanism releasably secures the first pintle in the first angular position and imparts a third resistive friction to the first pintle when the first pintle is rotated through the range of second angular positions.

DETAILED DESCRIPTION OF THE INVENTION

Certain terminology is used in the following description for convenience only and is not limiting. The words “right,” “left”, “lower” and “upper” designate directions in the drawings to which reference is made. The words “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the hinge assembly and designated parts thereof. The words “positive angular rotation” designate a rotation that increases the included angle between the display unit (or first member) and the roof of the vehicle (or second member), the included angle being zero when the display unit is in a first angular position adjacent to the roof. The words “negative angular rotation” designate a rotation that decreases the included angle between the display unit (or first member) and the roof of the vehicle (or second member). The terminology includes the words above specifically mentioned, derivatives thereof and words of similar import.

The present invention is directed to a hinge assembly for rotatably mounting a display unit to a surface. The surface can be any surface having a generally horizontal orientation, such as the interior facing surface of the roof of a vehicle, the underside of a shelf in a bookcase or a kitchen cabinet, a generally horizontally extending portion of a wall or the like. For the purpose of disclosing a detailed description of the invention, the interior facing surface of the roof of a vehicle will be used as representative of the surfaces to which the invention pertains. However, those having ordinary skill in the art will understand from this disclosure that the present invention is not limited to the mounting of a display unit to the roof of a vehicle and that the hinge assembly of the present invention is suitable for mounting a display unit to any surface having a generally horizontal orientation. Even more broadly, an artisan will understand that the hinge assembly of the present invention is suitable for rotatably coupling a first member to a second member for relative angular movement therebetween.

Referring to the drawings in detail, where like numerals indicate like elements throughout, there is shown inFIGS. 1-3a first preferred embodiment of a hinge assembly for an in-vehicle video system according to the present invention. More specifically, referring toFIG. 2, the first preferred embodiment is directed to a hinge assembly, generally designated10(hereinafter the “hinge assembly”) for rotatably mounting a display unit (not shown) having a display backing panel18in an interior of a vehicle having a roof (not shown). The hinge assembly10provides for movement of the display unit about an axis of rotation11between a first angular position12adjacent the roof, a second angular position14spaced from the roof and a range of third angular positions16spaced from the second angular position14. The second angular position14preferably is spaced an angular displacement of approximately twenty degrees from the first angular position12and the maximum range of the third angular positions16is preferably approximately one-hundred fifty degrees from the first angular position12. Those having ordinary skill in the hinge art will understand from the present disclosure that the second angular position14could be greater or less than twenty degrees without departing from the spirit and scope of the present invention. Similarly, the range of third angular positions could be greater or less than one-hundred fifty degrees.

Referring toFIGS. 1 and 2, the hinge assembly10has a first hinge bracket20for connecting the hinge assembly10to the roof. In a preferred embodiment, the first hinge bracket20preferably is die cast from a material such as zinc and preferably has an upper body19having a generally rectangular cross sectional shape. The upper body19has holes17extending therethrough for receiving threaded fasteners (not shown) and an upper surface21with a rib23projecting upwardly therefrom. The rib23is insertable in a slot25in a first roof mount22that is preferably attachable to the roof by bushing spacers24having a bore therethrough for receiving a threaded fastener (not shown) for securing the bushing spacer24to the roof. The first roof mount22is a generally elongated member, preferably fabricated from sheet metal, and has a pair of opposed, spaced apart, downwardly extending flanges27having holes15corresponding to the holes17in the upper body19of the first hinge bracket20. The first hinge bracket20is removably securable to the first roof mount22by threaded fasteners (not shown) insertable in the holes15,17in the first roof mount22and the first hinge bracket20, respectively.

The first hinge bracket20additionally has a first arm26, a second arm28spaced apart from the first arm28and a first stop30projecting from the first arm28. The first stop30is generally arcuate in shape and has a radially downwardly extending surface (not shown) parallel to the axis of rotation11of the hinge assembly10. Those having ordinary skill in the hinge art will understand from the present disclosure that the first roof mount22is not required to connect the first hinge bracket20to the roof and that there are numerous well known devices by which the first hinge bracket20could be connected to the roof, including the use of a variety of fasteners to directly attach the first hinge bracket20to the roof.

In the first preferred embodiment, the hinge assembly10has a first hinge mount32, preferably an aluminum die cast structure, for being connected by screw type fasteners (not shown) to the display backing panel18for rotation therewith. Preferably, the hinge assembly10further includes a latch (not shown) for being connected to the roof and for being operatively engagable with the display backing panel18for releasably securing the display unit in the first angular position12.

The first hinge mount32has a first step34projecting therefrom. The first step34is generally arcuate in shape and has a radially downwardly extending surface (not shown) parallel to the axis of rotation11of the hinge assembly10. The included angle between the radially downwardly extending surfaces of the first stop30and the first step34approaches zero when the angular displacement of the first hinge mount32approaches the limit the range of third angular positions16. Upon contact between the first stop30and the first step34, the limit of the range of third angular positions16has been reached and further rotation is prevented. Those having ordinary skill in the hinge art will understand from the present disclosure that the first step34and the first stop30are not required and that the range of third angular positions16could extend until the roof prevents further rotation.

A first pintle36, preferably constructed from steel, is secured to the first hinge mount32for rotation therewith, is rotatably connected to the first hinge bracket20and has an axis of rotation that is coincident with the axis of rotation11of the hinge assembly10. In the first preferred embodiment, the first pintle36is journaled for rotation within the first and second arms26,28of the first hinge bracket20. Additionally, the first pintle36has a first section38that extends beyond the first arm26. The first section38has a splined surface and is secured to the first hinge mount32by an interference fit in which the first section38of the first pintle36is inserted into a correspondingly splined bore in the first hinge mount32.

A first friction element40, preferably constructed from steel and preferably generally shaped in the form of a question mark in cross section, is secured by a knuckle41to the first hinge bracket20and rotatably engaged with the first pintle36. The first friction element40has an internal surface defining a generally cylindrical cavity. The diameter of the internal surface of the first friction element40is smaller than or equal to the diameter of the external surface of the first pintle36. The first friction element40receives the first pintle36within the cylindrical cavity with an interference fit, frictionally engages the external surface of the first pintle36and imparts a first resistive friction to the first pintle36when the first pintle36is rotated.

In the first preferred embodiment, the first friction element40imparts the first resistive friction to the first pintle36when the first pintle36is rotated in a first direction and imparts a third resistive friction to the first pintle36when the first pintle36is rotated in a second direction. A rotation in the first direction is a positive angular rotation that corresponds to a rotation of the display unit from the first angular position12in which the display unit is releasably secured to the roof toward the second angular position14. A rotation in the second direction is a negative angular rotation and is opposite to the first direction. The difference in the magnitude of the first and third resistive frictions arises due to a change in contact stresses between the internal surface of the first friction element40and the external surface of the first pintle36. The change in contact stresses is caused by a change in bending moment applied to the first friction element40and occurs when the direction of rotation changes.

The first resistive friction preferably has a magnitude that allows the display unit to freely fall in a controlled manner solely due to the weight of the display unit and gravity from the first angular position12to the second angular position14upon release of the latch securing the display unit in the first angular position12. The magnitude of the third resistive force preferably is greater than the magnitude of the first resistive force.

Those having ordinary skill in the hinge art will understand from the present disclosure that the magnitude of the first resistive force could be greater or less than the magnitude required to permit a controlled free fall of the display unit without departing from the spirit and scope of the present invention. Similarly, the artisan will also understand that the third resistive force could be greater or less than the magnitude of the first resistive force.

Referring toFIG. 3, a first detent mechanism42is secured to the first hinge bracket20and is rotatably engaged with the first pintle36. In the preferred embodiment, the first detent mechanism42includes a generally cylindrical-shaped first rocker44, preferably fabricated from a polymeric material, corresponding in length to the space between the first and second arms26,28of the first hinge bracket20. The first rocker44has a splined bore therethrough and is secured by an interference fit to a correspondingly splined circumferential surface35of the first pintle36for rotation therewith.

The first rocker44has a first or outer circumferential surface46having a first pair of generally opposing offset flats48that lie in spaced apart planes parallel to each other and to the axis of rotation11, a second pair of generally opposing offset arcuate surfaces50having a first radius and a fifth pair of generally arcuate surfaces51spaced from the axis of rotation11a distance less than half the distance between the spaced apart planes in which the first pair of generally opposing offset flats48lie. Those having ordinary skill in the art will understand from the discussion below that the fifth pair of generally arcuate surfaces51could have a arbitrary shape provided that the fifth pair of generally arcuate surfaces51does not contact the first detent spring52.

The first detent mechanism42has a generally U-shaped first detent spring52, preferably constructed from spring steel, that is secured, preferably by a rivet53, between the first and second arms26,28of the first hinge bracket20. The first detent spring52has integral thereto a first pair of lever arms54that are biased toward each other or inwardly biased. A first pair of bosses55integral to the first and second arms26,28of the first hinge bracket20preload the first pair of lever arms54with an inwardly directed spring force sufficient to restrain gravity induced rotation of the display unit by outwardly spacing apart the first pair of lever arms54to a distance approximately equal to the distance separating the spaced apart planes in which the first pair of generally opposing offset flats48lie.

The first detent mechanism42releasably secures the first pintle36in the second angular position14. In a preferred embodiment, when the first pintle36, and thus the display unit, is in the second angular position14, the first pair of lever arms54cooperates with and engages the first pair of generally opposing offset flats48. The first pair of lever arms54applies to the first pair of generally opposing offset flats48an inwardly directed spring force sufficient to restrain gravity induced rotation of the display unit thereby releasably securing the display unit in the second position14.

The first detent mechanism42additionally imparts a second resistive friction to the first pintle36when the first pintle36is rotated through the range of third angular positions16. In the preferred embodiment, when the first pintle36, and thus the display unit, is rotated through the range of third angular positions16, the first pair of lever arms54further cooperates with and engages the second pair of opposing offset arcuate surfaces50of the first rocker44. The first pair of lever arms54applies to the second pair of opposing offset arcuate surfaces50an inwardly directed spring force that imparts the second resistive friction to the first rocker44when the first pintle36is rotated through the range of third angular positions16.

Those having ordinary skill in the art of hinge design will understand that the present invention is not limited to construction from the preferred materials disclosed above or to any particular material. For instance, all the disclosed components of the hinge assembly10could be constructed from aluminum or stainless steel or a zinc alloy or engineered from polymeric materials without departing from the spirit and scope of the invention.

Referring toFIG. 1, the hinge assembly10additionally includes a second hinge bracket56, second pintle70, second friction element74and second detent mechanism76, all of which have substantially the same structure, in mirror image orientation, as the structure disclosed above. Accordingly, for brevity, the following disclosure incorporates therein the features of the corresponding structure disclosed above as if set forth in full.

The second hinge bracket56is spaced apart from the first hinge bracket20. The second hinge bracket56is connected to a second roof mount58which is also attached to the roof by bushing spacers24. The second hinge bracket56has a third arm60, a fourth arm62spaced apart from the third arm60and a second stop64. A second hinge mount66is spaced apart from and is generally parallel to the first hinge mount32. The second hinge mount66is for being connected by screw type fasteners (not shown) to the display backing panel18for rotation therewith. The second hinge mount66has a second step68cooperating with the second stop64to limit the range of third angular positions16.

A second pintle70is secured to the second hinge mount66for rotation therewith and has an axis of rotation that is coincident with the axis of rotation11of the hinge assembly10. The second pintle70is journaled within the third and fourth arms60,62of the second hinge bracket56and has a third section72extending from the third arm60of the second hinge bracket56. The third section72of the second pintle70connects the second pintle70to the second hinge mount66.

A second friction element74is secured to the second hinge bracket56for rotation therewith and is rotatably engaged with the second pintle70. The second friction element74imparts a fourth resistive friction, preferably having approximately the same magnitude as the first resistive friction, to the second pintle70when the second pintle70is rotated in the first direction and imparts a fifth resistive friction, preferably having approximately the same magnitude as the third resistive friction, to the second pintle70when the second pintle70is rotated in the second direction.

A second detent mechanism76also is provided. The second detent mechanism76has a generally cylindrical-shaped second rocker78secured to the second pintle70for rotation therewith. The second rocker78is substantially the same as the first rocker44and has a second or outer circumferential surface having a third pair of generally opposing offset flats, a fourth pair of generally opposing offset arcuate surfaces, and a sixth pair of generally opposing offset arcuate surfaces corresponding to the first pair of generally opposing offset flats48, the second pair of generally opposing offset arcuate surfaces50, and the fifth pair of generally opposing offset arcuate surfaces51of the first rocker44, respectively. The first or outer circumferential surface46of the first rocker44and the second or outer circumferential surface of the second rocker78are aligned on the first pintle36and the second pintle70, respectively, to act in unison. A generally U-shaped second detent spring86, substantially the same as the first detent spring52, is secured between the third and fourth arms60,62of the second hinge bracket56for rotation therewith.

The second detent spring86has a second pair of lever arms88that engages the second circumferential surface of the second rocker78. The second pair of lever arms88cooperates with the third pair of generally opposing offset flats to releasably secure the second pintle70in the second angular position14. The second pair of lever arms88further cooperates with the fourth pair of generally opposing offset arcuate surfaces to impart the sixth resistive friction, preferably having approximately the same magnitude as the second resistive friction, to the second rocker78when the second pintle70is rotated through the range of third angular positions16.

A spacer90having the general shape of a tube with a generally annular cross section is provided. The spacer has a first end92for receiving the second section96of the first pintle36and a second end94for receiving a portion of the fourth section98of the second pintle70. The spacer90is positioned between the second arm28of the first hinge bracket20and the fourth arm62of the second hinge bracket56. The first end92of the spacer90is connected by an interference fit to a second section96of the first pintle36. The second section96extends from the second arm28of the first hinge bracket20. The second end94of the spacer90is connected by an interference fit to a fourth section98of the second pintle70. The fourth section98of the second pintle70extends from the fourth arm62of the second hinge bracket56.

The hinge assembly10further includes an optical switch actuator assembly100for turning the display unit on and off. The optical switch actuator assembly100includes a rocker cam102with a splined bore for receiving a portion of the fourth section98of the second pintle70having an outer circumferential surface with splines corresponding to the splines in the bore of the rocker cam102. The rocker cam102is secured by an interference fit to the splined portion of the fourth section98of the second pintle70for rotation therewith. The optical switch actuator assembly100also includes a spring biased vane104keyed to a pivot pin106extending from the fourth arm62of the second hinge bracket56. The vane104has a lower portion110in follower contact with a boss112protruding from the rocker cam102and an upper arcuate portion108for interfering with a light beam (not shown), the obstruction of which causes an electronic circuit (not shown) to turn off the display unit. The vane104is aligned on the pivot pin106such that the light beam is obstructed and the display unit is off when the display unit is in the first position12and the light beam is unobstructed and the display unit is on when the display unit is rotated from the first position12. Those skilled in the art will understand from the present disclosure that there are numerous well known devices for turning the display unit on and off based upon the angular position of the display, including rotary mechanical switches, and that the use of an optical switch assembly is not limiting.

In use, the hinge assembly10is installed in the interior of a vehicle by securing the first and second hinge brackets20,56to the first and second roof mounts22,58which have been previously attached to the roof by bushing spacers24. This is accomplished by inserting the rib23of the first hinge bracket20in to the slot25in the first roof mount22and then inserting threaded fasteners into the holes15,17in the first roof mount22and the first hinge bracket20, respectively. The second hinge bracket56is similarly secured to the second roof mount58. Next, the display backing panel18supporting the display unit is secured to the first and second hinge mounts32,66by threaded fasteners. Finally, the display unit is releasable secured in the first angular position12to the roof by operatively engaging the latch with the display backing panel18.

To activate and view the display, a user of the display disengages the latch releasing the display unit. Under the force of gravity opposed by the combined first and fourth resistive frictions imparted to the first and second pintles36,70by the first and second friction elements40,74, the display unit rotates in the positive direction in a controlled manner approximately twenty degrees from the first angular position12to the second angular position14. As the display unit rotates, the rocker cam102secured to the fourth section98of the second pintle70rotates the vane104out of the path of the light beam, thereby activating the electrical circuitry that turns the display unit on. When the display unit rotates to the second angular position14, the display unit is releasable secured in the second angular position14by the first and second detent mechanisms42,76.

The occupant of the vehicle may position the display unit for optimal viewing within the range of third angular positions16by grasping and further rotating the display unit through a positive angular rotation, thereby increasing the included angle between the display unit and the roof. This is achieved by applying to the display unit a force necessary to overcome the combined first and fourth resistive frictions imparted by the first and second friction elements40,74and the second and sixth resistive frictions imparted by the first and second detent mechanisms42,76to the first and second pintles36,70. The occupant is prevented from rotating the display unit beyond the range of permissible third angular positions16by the first and second stops30,64and first and second steps34,68.

When the occupant has finished viewing the display unit, by a negative angular rotation, the display unit may be returned to the second angular position14and then to the first angular position12. This is achieved by first applying to the display unit the force necessary to overcome the combined third and fifth resistive frictions imparted by the first and second friction elements40,74and the second and sixth resistive frictions imparted by the first and second detent mechanisms42,76to the first and second pintles36,70and then the force necessary to overcome only the third and fifth resistive frictions. Upon reaching the first angular position12, the optical switch assembly100turns the display unit off and the display unit is securable to the roof by the releasable latch.

Referring toFIGS. 4-10, there is shown a second preferred embodiment of a hinge assembly according to the present invention. More specifically, referring toFIG. 4, there is shown a second preferred embodiment of a hinge assembly, generally designated210(hereinafter the “latchless hinge assembly”), for rotatably coupling a first member (not shown) to a second member (not shown). The latchless hinge assembly210provides for movement of the first member about an axis of rotation211between a first angular position212relative to the second member and a range of second angular positions214spaced from the first angular position214. Preferably, the first member is a display unit and the second member is a generally horizontal surface. However, those having ordinary skill in the art will understand from this disclosure that the first and second members can be any couplable structures between which relative rotational movement is desired. Preferably, in the first angular position212, the first member is adjacent to and spaced from the second member. The range of second angular positions214is preferably approximately one hundred thirty-five degrees from the first angular position212. Those having ordinary skill in the art will understand from this disclosure that the first angular position212could be an arbitrary angular displacement from the second member and that the range of second angular positions214could be greater or less than one hundred thirty-five degrees without departing from the spirit and scope of the present invention.

Generally, the materials from which the components of the latchless hinge assembly210are formed are substantially the same as the materials discussed above for the hinge assembly10and, for brevity, will not be further discussed.

Referring toFIGS. 4-6and8-9, the latchless hinge assembly210has a first hinge bracket220for connecting the latchless hinge assembly210to the second member. In the preferred embodiment, the first hinge bracket220is generally L-shaped and has an upper body219that is integral with and generally perpendicular to a lower body221. The upper body219has a generally rectangular cross-sectional shape. Holes217extend through the upper body219and are for receiving threaded fasteners (not shown) for removably securing the first hinge bracket220to the second member. The lower body221has a first rib222and a second rib223spaced from the first rib222.

The latchless hinge assembly210also has a first hinge mount232for connecting the latchless hinge assembly210to the first member. In the preferred embodiment, the first hinge mount232has a backing panel218integral thereto for being connected by screw type fasteners (not shown) to the first member.

A first pintle236is secured to the first hinge mount232for rotation therewith, is rotatably connected to the first hinge bracket220and has an axis of rotation that is coincident with the axis of rotation211of the latchless hinge assembly210. In the preferred embodiment, the first pintle236is journaled for rotation within the lower body221of the first hinge bracket220. Additionally, the first pintle236has a first section238that extends beyond the second rib223of the lower body221of the first hinge bracket220. The first section238has a splined surface and is secured to the first hinge mount232by an interference fit in which the first section238of the first pintle236is inserted into a correspondingly splined bore in the first hinge mount232.

A first friction element240is secured to the first hinge bracket220and rotatably engaged with a center section237of the first pintle236. The first friction element240preferably is generally shaped in the form of a question mark in cross section. Those having ordinary skill in the art will understand from the present disclosure that the first friction element240may have other forms including an open friction collar or wrap spring that substantially circumferentially surrounds a portion of a length of the first pintle236and that the first friction element240may be integral with the first hinge bracket220without departing from the spirit and scope of the present invention.

The first friction element240preferably is disposed in a bore224in the lower body221of the first hinge bracket220and is secured to the first hinge bracket220by a knuckle241that extends from the friction element240into a channel225in the bore240. The first friction element240has an internal surface defining a generally cylindrical cavity. The diameter of the internal surface of the first friction element240is smaller than or equal to the diameter of the external surface of the center section237of the first pintle236. The first friction element240receives the first pintle236within the cylindrical cavity with an interference fit, frictionally engages the external surface of the first pintle236and imparts a first resistive friction to the first pintle236when the first pintle236is rotated.

In the first preferred embodiment, the first friction element240imparts the first resistive friction to the first pintle236when the first pintle236is rotated through a positive angular rotation and imparts a second resistive friction to the first pintle236when the first pintle236is rotated through a negative angular rotation. The difference in the magnitude of the first and second resistive frictions arises due to a change in contact stresses between the internal surface of the first friction element240and the external surface of the first pintle236. The change in contact stresses is caused by a change in bending moment applied to the first friction element240and occurs when the direction of rotation changes. The magnitude of the second resistive force preferably is greater than the magnitude of the first resistive force. However, those having ordinary skill in the hinge art will understand from the present disclosure that the magnitude of the first resistive force could be greater or less than the magnitude of the second resistive force without departing from the spirit and scope of the present invention.

Referring toFIGS. 4-6and8, a first detent mechanism242is secured to the first hinge bracket220and is rotatably engaged with the first pintle236. In the preferred embodiment, the first detent mechanism242includes a generally cylindrical-shaped first rocker244corresponding in length to the distance between the first and second ribs222,223of the first hinge bracket220. The first rocker244has a splined bore therethrough and is secured by an interference fit to a correspondingly splined circumferential surface235of the second section239first pintle236for rotation therewith.

The first rocker244has a first or outer circumferential surface246having a first pair of generally opposing offset flats248that lie in spaced apart planes parallel to each other and to the axis of rotation211and a first pair of generally opposing arcuate surfaces250. Preferably, the first pair of offset flats248and the first pair of arcuate surfaces250extend the entire length of the first rocker244. However, those of ordinary skill in the art will understand from the present disclosure that the first pair of offset flats248and the first pair of arcuate surfaces250extend over only a portion of the first rocker244without departing from the spirit and scope of the present invention.

The first detent mechanism242preferably has a generally U-shaped first detent spring252that is secured to the first rib222of the first hinge bracket220by a peg251having a hole253through which a stud255projecting from the first rib is inserted. The first detent spring252has integral thereto a first pair of lever arms254that are biased toward each other or inwardly biased.

The first detent mechanism242releasably secures the first pintle236in the first angular position212. In the preferred embodiment, when the first pintle236, and thus the first member, is in the first angular position212, the first pair of lever arms254cooperates with and engages the first pair of generally opposing offset flats248. The first pair of lever arms254applies to the first pair of generally opposing offset flats248an inwardly directed spring force sufficient to restrain rotation of the first member thereby releasably securing the first member in the first angular position212.

The first detent mechanism242additionally imparts a third resistive friction to the first pintle236when the first pintle236is rotated through the range of second angular positions214. Preferably, when the first pintle236, and thus the first member, is rotated through the range of second angular positions214, the first pair of lever arms254further cooperates with and engages the first pair of opposing offset arcuate surfaces250of the first rocker244. The first pair of lever arms254applies to the first pair of opposing offset arcuate surfaces250an inwardly directed spring force that imparts the third resistive friction to the first rocker244when the first pintle236is rotated through the range of second angular positions214.

Referring toFIGS. 5 and 6, the extent of the range of second angular positions of the first member about the axis of rotation211is limited, preferably to approximately one hundred thirty-five degrees, by a step230that prevents further rotation of a stopper228secured to the first pintle236. In the preferred embodiment, the step230is formed by a cutout in the edge of one arm of the pair of lever arms254of the first detent spring252. The stopper228preferably is an annular ring with a generally D-shaped bore and is secured by an interference fit to a correspondingly D-shaped circumferential surface of a portion of the first pintle236between the center section236and second section239of the first pintle236. The stopper228has a radially outwardly projecting tongue229positioned for contact with the step230when the first member approaches the limit of the range of second angular positions214.

Referring toFIGS. 4,7and10, the latchless hinge assembly210additionally includes a second detent mechanism276secured to a second hinge bracket256. The second detent mechanism276rotatably engages a second pintle270secured to and extending from the first hinge mount232. The second pintle270has an axis of rotation that is coincident with the axis of rotation211of the hinge mount210. Those having ordinary skill in the art will understand from this disclosure that the second pintle270may be integral with and an extension of the first pintle236without departing from the spirit and scope of the present invention. The second detent mechanism releasably secures the second pintle270in the first angular position and imparts a fourth resistive friction to the second pintle270when the second pintle270is rotated through the second range of angular positions214.

The second hinge bracket256has an upper body258that is substantially similar to the upper body219of the first hinge bracket220. The lower body260has a first arm261and a second arm262spaced from the first arm261. The second pintle270is journaled for rotation within the first and second arms261,262.

In the preferred embodiment, a generally cylindrical-shaped second rocker278, substantially the same as the first rocker244discussed above, is located between the first and second arms261,262of the lower body260of the second hinge bracket256and is secured to the second pintle270for rotation therewith. The second rocker278includes a second circumferential surface280having a second pair of generally opposing flats282and a second pair of generally opposing arcuate surfaces284.

The second detent mechanism276preferably has a generally U-shaped second detent spring286substantially the same as the first detent spring252discussed above. The second detent spring286has a second pair of lever arms288that is integral with and spaced apart by an upper member290. The second pair of lever arms288is biased toward each other or inwardly biased. The upper member290of the second detent mechanism276has extending from opposed sides thereof a pair of tabs291that are received with an interference fit within a pair of slots294in the first and second arms261,262of the lower body260of the second hinge bracket256to secure the second detent spring286to the second hinge bracket256.

The second pair of lever arms288engages the second circumferential surface280of the second rocker278. More specifically, in the preferred embodiment, the second pair of lever arms288cooperate with the second pair of generally opposing offset flats282to releasably secure the second pintle270in the first angular position212and further cooperate with the second pair of opposing arcuate surfaces284to impart the fourth resistive friction to the second rocker278when the second pintle270is rotated through the range of second angular positions214.

The latchless hinge assembly210is used in a manner similar to the manner disclosed above for the hinge assembly10. The salient difference is that the latchless hinge assembly210does not require a latch and accordingly does not provide as a feature controlled rotation under the force of gravity from a first position to a second position. More specifically, a display unit mounted to the first hinge mount232is releasably secured in the first position212adjacent to and spaced from a horizontal surface, to which the first hinge bracket220is attached by the spring force imparted to the first and second pintles236,270by the first and second detent mechanisms242,276. The display unit will remain in the first position until a force necessary to overcome the spring force is applied. Subsequent application of a first force necessary to overcome the combined first resistive friction of the first friction element240and the third and fourth resistive frictions of the first and second detent mechanisms242,276rotates the display unit through a positive angular displacement within the range of second angular positions214. Rotation beyond the range of permissible second angular positions214is prevented by the stopper228and the step230. Application of a second force necessary to overcome the combined second resistive friction of the first friction element240and the third and fourth resistive frictions of the first and second detent mechanisms242,276rotates the display unit through a negative angular displacement until the display unit is returned to the first angular position212and releasable secured in that position by the spring force applied by the first and second detent mechanisms242,276.

Those skilled in the art will appreciate that changes could be made to the embodiment described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.