Locking Spring Hinge

Abstract

A resiliently biased locking element travels in free sliding relation over an arcuate surface throughout the major extent of oscillatory movement of a rocking lever associated with a linked lever system of a door hinge especially useful for pieces of furniture, whereby the door is freely movable between a fully open position and a fully closed position, the resiliently biased locking element engaging a detent surface leading from the arcuate surface close to the fully closed position of the door, avoiding terminal slamming of the door, but obtaining a satisfactory locked door relationship. By having either the locking element or the surfaces on which it runs formed of or treated with a self-lubricating material such as a suitable plastic, wear-free operation is effected.

Description

BACKGROUND OF THE INVENTION

This invention relates to locking spring hinges, and in particular to hinges of this type especially useful in furniture such as cabinets and the like.

There has been considerable development in hinges for furniture doors provided with means for automatically locking and retaining a fully closed position of the door until the door is deliberately opened manually. Hinges of this type are provided with parts that are respectively attached to the door and to a stationary part of the associated piece of furniture, with a suitable connecting lever system, with a locking spring and detent arrangement such that when the door is at approximately half-open position, the locking spring causes the door to be urged into its complete closing position and then to maintain it closed. In most cases the dead center is close to the open position. Therefore, shortly after start of closing a completely opened door, the spring will begin exerting a closing force so that if the door is released from restraint, the spring acts in a manner to accelerate movement of the door to closing position in spite of decreasing spring tension. This results in often undesirable slamming of the door, and can have a dangerous smashing effect on a person's hand or finger.

It is, accordingly, an important object of the present invention to overcome the foregoing and other disadvantages, deficiencies, inefficiencies, shortcomings and problems in prior self-locking hinges of the character indicated, and to attain important improvements and advantages and new and improved results in a novel locking spring hinge as will hereinafter become apparent.

Another object of the invention is to provide a new and improved locking spring hinge in which the locking effect is attained efficiently and with adequate resilient bias force, but without effecting a closing force on the door until the door is almost fully closed.

A further object of the invention is to provide a new and improved locking spring hinge which has an excellent door locking function, but is free from undesirable door closing acceleration.

Still another object of the invention is to provide a new and improved door hinge especially suitable for furniture doors and which has a new and improved self-locking device free from undesirable terminal closing acceleration effects.

Other objects, features and advantages of the invention will be readily apparent from the following description of certain preferred embodiments thereof, taken in conjunction with the accompanying drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts embodied in the disclosure, and in which:

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional plan view of a hinge construction embodying features of the invention, showing the relationship of parts in a partially open position of a door with which associated;

FIG. 2 is an enlarged, fragmentary, generally schematic illustrative section plan view demonstrating the relationship of the resiliently biased locking element and the fixed locking and control element of the hinge assembly in fully door open and fully door closed relationships;

FIG. 3 is an outer end elevational view of the door-mounted hinge-anchoring socket member of the hinge assembly;

FIG. 4 is a view similar to FIG. 2, but showing a slight modification;

FIG. 5 is a view similar to FIG. 2, but showing another modification; and

FIG. 6 is a similar view showing a further modification.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

By way of illustration, a typical knuckle hinge joint embodying features of the invention is shown in FIG. 1 wherein a supporting wall 1 alongside an opening in, for example, a piece of furniture such as a cabinet, has associated therewith a door 2 for closing the opening. Supporting and connecting the door 2 for opening and closing movements relative to the wall 1, is a knuckle joint hinge assembly comprising a linked lever system including hinge arms and rocking levers connected to and between a wall supported stop bracket comprising an anchoring member 3 suitably attached by means of a mounting plate 4 to the wall 1. Mounted in the customary manner recessed within the inner face of the door 2 adjacent to its edge nearest the supporting wall 1 is a hinge socket 5 which may be made as an injection molded plastic part. Connected to and between the stop bracket member 3 and the stop socket 5 is a linked lever system including a hinge arm 6 and a hinge arm 7 connected together in relatively pivotal relation by a pivot pin 8. In this instance the hinge arm 7 comprises twin coextensive spaced arm portions 7a connected by an integral web 7b, with the arm 6 extending from its pivotal connection 8 in generally crosswise direction relative to the arm 7 and having one end pivotally attached by means such as a hinge pin 9 to an end portion of the bracket member 3 located adjacent to the door 2 and in the fully closed position of the door received in the door mounted stop member 5 which is of generally dished shape, as shown, for this purpose. Pivotal connection of the arm 7 to the member 5 is by means of a hinge pin 10. Connection of an opposite end of the arm 6 with the member 5 is through the medium of a rocking lever 11, and connection of an opposite end of the arm 7 with the bracket member 3 is through the medium of a rocking lever 12. Pivotal connection of the lever 11 with the member 5 is by means of a hinge pin 13 while a hinge pin 15 connects the lever 11 with the arm 6. Connection of the rocking lever 12 with the member 3 is by means of a hinge pin 14 and connection of the rocking lever 12 with the arm 7 is effected by means of a hinge pin 16. Through this arrangement, the door 2 is guided by the linked lever system between a fully open and a fully closed position, the position of the door 2 in FIG. 1 being at about a 45.degree. open position.

According to the present invention, new and improved self-locking means are provided in the hinge structure which will function efficiently to hold the door against unintentional opening, which will release with moderate manual door-opening force, which will permit the door to be swung easily and without restraint between fully open and almost fully closed positions, unless additional locking or semi-locking positions are desired at intervals in the opening of the door, and which will act with only minimal terminal closing effect upon the door after the door reaches nearly the fully closed position so that accelerated closing or slamming of the door are avoided. To this end, the hinge assembly is provided with a resiliently biased locking element and a control locking cam element cooperatively related thereto. Although it will be apparent that these cooperating locking elements may take various forms and may be located in their cooperative relation at various places in the assembly, and in association with the linked lever system and either the door 2 or the wall 1, a preferred arrangement comprises mounting the locking elements in association with the rocking lever 12 and the bracket member 3, substantially as shown in FIGS. 1 and 2. For this purpose, one of the rocking levers 11 or 12, and in the illustrated instance the rocking lever 12 carries as a resiliently biased locking element an integral finger portion 17 swingably located in a slot 18 provided within the body of the lever 12 in a plane normal to the axes of the pivots 14 and 16 and with the finger 17 attached as by means of an integral connection 19 to the body of the lever 12 which for this purpose may be formed from suitable plastic material as by an injection molding process, or any other preferred process wherein the body of the lever 12 and the finger 17 comprise a one piece structure. At its free end, the swingably supported locking element finger 17 cooperates with a fixed locking and control element 20 carried by the adjacent end portion of the mounting bracket member 3 and desirably comprising an integral ear-like projection thereon of a width to be received freely in the slot 18 and serving as support for the pin 14 on which the adjacent end portions bifurcated by the slot 18 of the lever 12 are mounted. In a desirable construction, the bracket member 3 with the ear-like element 20 may be a metal piece which can be readily mass produced as a die casting.

A cooperative relationship between the locking element 17 and the locking element 20 attaining the desirable objects of the present invention results from riding of a detent tip formation 21 on the free end of the element on a cam edge surface 22 on the element 20. For this purpose, a cam surface 22 is of a segmental arcuate shape and throughout the major extent of its length concentric with the axis of the pin 14 and thereby concentric with the arc of movement of the pivot pin 16, except for a short distance at its end remote from the door 2 and facing generally away from the lever system and which provides a locking shoulder 23 desirably formed on a rapidly diminishing radius relative to the axis 14. Through this arrangement, when the lever 12 is in the position assumed in the fully closed position of the door 2, the locking element detent 21 will lockingly engage the locking shoulder 23 and resist opening of the door to the extent of resilient bias of the locking element 17. The locking cooperation of the detent 21 and the shoulder 23 is enhanced by complementary shape of the opposed locking surfaces whereby the locking surface of the detent 21 engages substantially throughout the length of the shoulder 23 which may be formed on a radius of curvature substantially the same as the radius of curvature of the major extent of the cam edge 22 and joining the same on a curved transition surface area 24 at a lobe projection of the element 20 and over which the detent 23 travels in movement as the rocking lever 12 moves to and between the door closed position thereof as shown in FIG. 2 and the door open position thereof as shown in dot-dash outline in FIG. 2. Because the smoothly rounded shape of the cam edge surfaces 22, 23 and 24 and the complementary contacting locking edge of the detent 21 of substantial length, an exceedingly smooth riding of the detent on the cam surfaces assures ease and smoothness of operation. Furthermore, as the detent surface rides over the transition surface 24 of the cam, bias of the element 17 toward the cam will have minimal door closing effect so that not until the rocking lever 12 has reached very close to the fully door closed position will the detent 21 attain its locking effect and draw the door completely closed and hold the door in such closed position. Likewise, in opening the door after only a short opening swinging of the rock lever 12 with the opening door, the detent 21 leaves the shoulder 23 due to the substantial differential in center of radius between the shoulder surface 23 and the main surface 22 of the cam edge and the detent 21 rides smoothly on the transition surface 24 toward the main extent of the surface 22 smoothly for easy continuing opening of the door.

Although the locking or detent finger element 17 may through its integral attachment 19 with the body of the lever 12 be possessed of adequate resilient bias toward the locking element, in the interests of compactness and ease and uniformity of operation, the connection 19 may, as shown, be relatively flexible and mechanical biasing means in the form of a spring 25 supplied to provide a desired resilient bias for the element 17. While the spring 25 may take any desired form such as coiled compression, hairpin wire torsion, and the like, a preferred, economical, simple and efficient form comprises a generally U-shaped leaf spring structure the bight of which is engaged on the pivot pin 16 within the slot 18. A biasing leg 26 of the spring bears against the inner side of the finger 17 to thrust it outwardly toward the element 20, while a backup leg 27 of the spring engages an abutment 28 provided on the lever 12, maintaining the spring under tension for thrusting of the leg 26 toward the element 17. To prevent the spring 25 from accidentally displacing out of the slot 18 and away from its bight engagement with the pin 16, interlock means are provided on the spring leg 27 comprising a return bent or hooked interlock shoulder terminal 29 engaging interlockingly with an oppositely facing interlock shoulder 30 at the adjacent end of the thrust shoulder formation 28. Through this arrangement, the spring 25 moves with the rocking lever 12 and the locking shoe element 17 and maintains a constant resilient bias on the locking element 17 toward the locking element 20. Assembly of the spring 25 into the hollow slot space 18 within the rocking lever 12 is easily effected by inserting the legs 26 and 27 into the outer open end of the hollow slot space 18 and pushing the spring inwardly until its bight engages the pin 16 and the interlocking shoulder terminal 29 snaps behind the innerlock shoulder 30. In the assembled relationship with the finger locking element 17, ample space is provided between the spring legs 26 and 27 for full range of resilient flexing movements of the leg 26 with the locking detent finger element 17 between the relatively expanded locking relationship in the closed door position of the rock lever 12 as shown in full in FIG. 2 and the relatively compressed relationship of the spring in the open position of the lever 12 shown in dot-dash position in FIG. 2.

For some purposes, it may be desirable to have, in addition to the door closed locking position at least one intermediate door locking position and alternatively, or in addition, a fully door open locking position and in which additional locking positions an equally firm retention of the door as in the closed door position may be provided for, although the additional locking position or positions may be of lesser locking or door arresting retention magnitude. As shown in FIG. 4, wherein all features of the device are the same as in FIG. 2 except for the additional locking positions, the detent 21' of the locking shoe element 17' may be accentuated as a small radius projection. Not only is the detent projection 21' engageable in locking relation with the shoulder 23, but also in any one or more desired locking positions along the otherwise free riding or gliding control cam profile edge surface 22. For example, an intermediate door open position may be determined by a detent receiving interlock shoulder recess 31 in the surface 22. Alternatively, or in addition thereto, an open door interlock recess 32 may be provided in the surface 22 receptive of the detent 23 in the fully open position of the door.

As previously stated, the door mounting member 5 of the hinge assembly may be in the form a cast or injection molded plastic member of generally dish shape. For a better understanding of this part, attention is directed to FIG. 3 showing a plan view looking into the member which is provided at opposite sides with means such as screw hole bores 33 to facilitate securing the member as set into the door with which associated. In order to withstand the unlocking and other operating forces to which the hinge assembly is subjected in use, and for efficient and reliable supporting of the associated members of the hinge lever system and to preclude looseness or shifting in the direction of the axis of rotation, special attachment provisions are made for the knuckle joint arm 7. For this purpose, the member 5 is provided with sturdy land body portions at the opposite sides through which the respective pivot pins 10 and 13 are engaged, and respective slot recesses 34 are provided for sliding guiding reception of the terminal portions of the arm side plate parts 7a. Thus, by supporting these two terminal portions of the arm 7 from both sides thorough resistance is provided for against the weight of the door causing a shifting relative to the arm 7. Furthermore, continuations of the two slot recesses 34 comprising elongated grooves 35 receive shoulder portions 36 of the arm parts 7a. By having the shoulder portions 36 slightly extended as shown in FIG. 1 and engaging closely within the shallow slots 35 in the closed position of the door, increased mechanical stability is attained.

Although the arrangement of FIGS. 1 and 4 provides effective results with the provision of the fixed locking element of metal and the resiliently biased locking element of plastic and thus provided with a plastic detent sliding shoe in engagement with the control surface of the fixed element, for situations where an even more wear-resistant relationship and to extend the life expectancy attainable where one of the elements has a plastic rubbing or shoe surface, the exemplary embodiments of FIGS. 5 and 6 may be employed. In these forms of the invention, the fixed locking and control element 20' comprises a metal core 37 which may be similarly as in the case of the previously described element 20 formed integrally with the mounting bracket member 3' and serve as pivot anchorage through the pivot pin 14' for the rocking lever 12' which carries the pivot pin 16' by which the lever is operatively connected with the hinge lever system. To provide a lobed control cam surface a plastic cover 38 is permanently mounted on the core 37. If preferred for proper conditions, the entire element 20' may be made from plastic either integral with the bracket member 3' or secured thereto. Through this arrangement, a continuous plastic control and locking surface structure is provided including a semicircular segmental free riding surface length 22' (FIG. 5) a locking surface 23' and a transition arcuate surface 24' between the surface portions 22' and 23'. Thereby a long plastic path is provided for engagement by the resiliently biased locking element which in this instance comprises the spring 25' directly having on its tensioned leg 26' a locking interlock shoe 39 functioning to engage in locking relation with the locking shoulder surface 23' in the closed door position of the lever 12' and gliding with limited contact over the surfaces 22' and 24' in the opening and closing movements of the door whereby wear per unit area is diminished to a minimal fraction. In this instance, of course, the hollow space provided by the slot 18' within the lever 12' is fully open toward the fixed element 20' for thrusting of the spring leg 26' thereagainst as maintained under tension by backing of the leg 27' of this U-shaped spring 25' against the shoulder surface 28' within the lever. Interlocking of the spring leg 27' against displacement of the spring 25' from the hollow lever 12', in cooperation with the pivot pin 16' about which the bight of the spring is engaged, is provided for by an interlock lug 40 projecting inwardly from the thrust shoulder surface 27' into an interlock aperture 41 formed in the leg 27'. In this construction, similarly as in the previously described construction, the spring 25' is adapted to be assembled by thrusting its legs into the hollow 18' within the lever 12' until the spring bight engages about the pivot pin 16' and the interlock aperture 41 receives the interlock lug 40 and at which time the turned detent shoe 39 of the spring leg 26' will engage tensionably with the fixed locking member 20'.

Another feature which may be noted in the form of FIG. 5 resides in that the dead center position between the resiliently biased and fixed locking elements, as represented by the transition surface 24' between the free riding surface 22' and the locking surface 23' is extended in the door closing direction as compared, for example, with the position of the intermediate or dead center surface 24 in FIG. 2. Thereby, on closing of the door, a slightly greater closing push force must be exerted in order to overcome the slightly increased tensioning of the locking spring to move it beyond dead center to the closing position. In addition, of course, the closing effect is improved in the last short interval of movement to the fully closed position, and the resiliently biased locking element attains a particularly advantageous locking tension with the locking surface 23'.

If it is desired to shorten the interval at closing of the door during which the resiliently biased locking element assumes locking control, the dead center position may be correspondingly lengthened in the direction of the door closing movement, as represented in FIG. 6. Therein all parts of the disclosure are the same as in FIG. 5, except that the plastic cam surface part 38' has an extended lobe 42 which thereby effects an extension in length of the free glide surface 22" whereby the spring leg 26' is placed under substantial increased tension as it approaches the transition surface 24" and the locking engagement of the spring leg 26' occurs in the final very close to door closed position with the locking engagement of the leg with the locking surface 23" occurring close to the surface 24" in an extremely small interval of travel. However, by reason of the substantially increased tensioning of the locking spring, immediately upon leaving the dead center position to the locking position, an extremely reliable tension locking relationship is attained, the locking tension being greater than in either of the forms of FIG. 2 or 5. Because the locking engagement of the spring with the fixed locking element is so close to the arcuate transition surface 24", a smooth opening of the door can be readily effected when desired. Moreover, due to the substantial tension of the locking spring element leg 26' thrusting against the beginning reach of the glide surface 22' after leaving the transition surface 24", a desirable door opening bias is provided to facilitate opening of the associated door, with the tension diminishing as the rocking lever 12' advances toward the fully open door position.

It will thus be apparent that the embodiments of FIGS. 5 and 6 provide for a wide selective range of locking spring action to meet numerous and varied requirements. Such variations can be attained in a particularly simple and inexpensive manner in that it is not necessary to produce a special hinge construction for each requirement, but the desired result can be attained by varying the cam surface profile of the plastic control portion 38, 38' of the fixed locking element 20'. Thereby the core part 37 and other parts of the hinge assembly can be standardized in construction, and any selected form of the plastic portion, of which a range of sizes may be stocked in inventory, can be applied to the standard core. Product costs and inventory problems are thus reduced while enabling inexpensive attainment of a large range of cam surface profiles to meet numerous requirements speedily.

Although various minor modifications might be suggested by those versed in the art, it should be understood that we wish to embody within the scope of the patent warranted hereon all such embodiments as reasonably and properly come within the scope of our contribution to the art.

Claims

We claim as our invention:

1. A locking spring hinge having means for fixed mounting on a wall adjacent an access opening in a piece of furniture, means for mounting to a door adapted to close the opening, and articulating lever arm structure pivotally connected to and between said means and operable to support the door and control movement of the door between open and closed positions relative to the opening, comprising:

an oscillatable rocking lever pivotally connected at one end to a lever arm of said lever arm structure and pivotally connected at an opposite end to one of said means;

a locking element carried by and movable with said rocking lever;

a locking element carried by said one means;

one of said locking elements being resiliently biased toward the other of said locking elements;

said other locking element having a glide surface along which said biased locking element rides and maintaining said one element against bias thrust effect in a closed door direction throughout a major extent of rocking oscillations of said rocking lever between the open door and closed door positions;

said other locking element having a locking shoulder surface leading from said glide surface and with which shoulder surface said biased locking element engages in the closed door position of said rocking lever for thereby maintaining the closed door position by resilient thrust of the biased locking element against said locking shoulder surface;

said other of said locking elements comprising a mounting ear rigid with said one of said means;

said rocking lever having a slot within which said ear is received;

pivot means connecting the rocking lever to said ear;

said ear having said glide and locking shoulder surfaces thereon in cam profile; and

said resiliently biased locking element being carried by said rocking lever within said slot.

2. A hinge according to claim 1, said rocking lever having a pivot pin extending across said slot spaced from said fixed locking element, and said resiliently biased locking element including a generally U-shaped spring having its bight engaged over said pivot pin, shoulder means on said lever and providing a thrust backing for one leg of said spring, and another leg of said spring being thereby maintained in tensioned bias toward said fixed locking element.

3. A hinge according to claim 1, wherein said other locking element comprises a metal core having fixedly thereon a plastic portion providing said surfaces.

4. A hinge according to claim 1, wherein said other locking element has a lobed cam profile providing said surfaces and including a lobe extension of said glide surface in the direction of closing movement of said resiliently biased element along the glide surface effecting an increase of tension of the biased element as it approaches a dead center position adjacent to said locking shoulder surface, and movement of said resiliently biased element from dead center to said locking surface being within a small incremental remaining movement of said rocking lever into the closed door position, whereby to avoid acceleration in the door closing movement.

5. A locking spring hinge having first means for fixed mounting on a wall adjacent an access opening in a piece of furniture, second means for mounting to a door adapted to close the opening, and articulating lever arm structure pivotally connected to and between said means and operable to support the door and control movement of the door between open and closed positions relative to the opening, comprising:

an oscillatable rocking lever pivotally connected at one end to a lever arm of said lever arm structure and pivotally connected at an opposite end to said first means;

a locking element carried fixedly by said one means adjacent to said rocking lever and having a glide surface and a locking shoulder surface leading from said glide surface;

a resiliently biased locking element comprising a generally U-shaped spring carried by and movable with said oscillatable rocking lever and having one leg biased toward said glide and locking surfaces; and

said rocking lever being made from plastic material and having a low-friction detent shoe comprising a finger element integrally connected flexibly with the rocking lever and interposed between said spring leg and said surfaces and functioning in oscillating movements of the rocking lever to ride along said surfaces, maintaining the elements free from door closing bias effect of the spring while the detent shoe rides said glide surface and effecting a door closing engagement with said locking shoulder in the closed door position of the elements.

6. A locking spring hinge having means for fixed mounting on a wall adjacent an access opening in a piece of furniture, means for mounting to a door adapted to close the opening, and articulating lever arm structure pivotally connected to and between said means and operable to support the door and control movement of the door between open and closed positions relative to the opening, comprising:

an oscillatable rocking lever pivotally connected at one end to a lever arm of said lever arm structure and pivotally connected at an opposite end to one of said means;

a locking element carried by and movable with said rocking lever;

a locking element carried by said one means;

one of said locking elements being resiliently biased toward the other of said locking elements;

said other locking element having a glide surface along which said biased locking element rides and maintaining said one element against bias thrust effect in a closed door direction throughout a major extent of rocking oscillations of said rocking lever between the open door and closed door positions;

said other locking element having a locking shoulder surface leading from said glide surface and with which shoulder surface said biased locking element engages in the closed door position of said rocking lever for thereby maintaining the closed door position by resilient thrust of the biased locking element against said locking shoulder surface;

a lever arm pivotally attached at one end to said rocking lever and having an opposite end comprising a pair of spaced co-extensive parallel side portions;

the remaining of said mounting means comprising a member having parallel slots therein within which said parallel side portions are pivotally engaged; and

a pivot pin securing said parallel side portions pivotally to said mounting member and in said slots.

7. A knuckle joint hinge assembly including a first member adapted to be mounted on a wall adjacent to an opening adapted to be closed by a door and a second member adapted to be mounted on the door, comprising:

a hinge arm connected to the second member;

a rocking lever for at least controllably connecting the rocking lever with said one member, including means pivotally connecting the rocking lever to said one member and a hinge pin connecting the rocking lever to said hinge arm;

a U-shaped locking spring having a closed end engaged about said hinge pin with one leg of the spring bearing against a fixed abutment on said rocking lever;

a guide surface fixedly on said one member and toward which a second arm of the spring thrusts with spring bias;

said guide surface having a portion thereof which is arcuate substantially concentric with an arc of movement of said hinge pin in movements of the hinge arm and rocking lever during opening and closing movements of the door such that bias of said second spring leg toward the arcuate surface avoids influencing the door in closing direction; and

said guide surface having an end portion of substantially decreased radius and leading to a locking surface such that the second spring leg can act with an easy transition from the open door bias toward said arcuate portion of the surface to the locking portion of the surface wherein bias of the second leg maintains the closed door position releasably.

8. A knuckle joint hinge assembly according to claim 7, wherein said surface comprises a low friction plastic material.

9. A knuckle joint hinge assembly according to claim 7, wherein said surface comprises a lobed cam profile including a lobe extension of said arcuate surface portion in the direction of closing movement of the second spring leg along the surface and effecting an increase of tension of the second leg as it approaches a dead center position adjacent to said locking portion of the surface, and movement of said second leg from the dead center position to the locking portion of the surface being within a small incremental remaining movement of the rocking lever into its closed door position, whereby to avoid acceleration in the door closing movement.

10. A knuckle joint hinge assembly according to claim 7, wherein said surface is provided on a mounting ear rigid with said first member, said rocking lever having a slot within which said ear is received, pivot means connecting the rocking lever to said ear, and said spring being located within said slot.

11. A knuckel joint hinge assembly according to claim 10, including a low-friction detent shoe comprising a finger element flexibly connected to the rocking lever within said slot and interposed between said second spring leg and said surface.

12. A knuckle joint hinge assembly according to claim 7, wherein said second spring leg engages directly with said surface.

13. A knuckle joint hinge assembly according to claim 7, including complementary interlocked interlock means on said first spring leg and on said rocking lever.

14. A knuckle joint hinge assembly according to claim 7, wherein said hinge arm has one end thereof pivotally connected to said rocking lever by said hinge pin and has in the opposite end thereof a pair of spaced coextensive parallel side portions, said second mounting member having parallel slots therein within which said parallel side portions are pivotally engaged, and a pivot pin traversing said slots and extending through said side portions.