US3854166A - Cast hinge - Google Patents

Abstract

A cast hinged article and the method and apparatus for simultaneously casting both parts of the article. A first part of the article is formed with inner projections, and a second part of the article is formed thereover to enclose the projections to provide a hinged pivot. A staking unit which includes a punch then distorts the material in the first part adjacent the projections so that the pivot will be freely movable.

Description

United States Patent 11 1 Hannes i 1 CAST HINGE [75] lnventor: Ka rl Hannes, White Plains, NY. [56] References cued 73 A C Cl I N Y k UNITED STATES PATENTS sslgnee' 6W 3.497908 3/1970 Zamarra 1. 16.4 1

[ Notice: The portion of the term of this Primary Examiner-Paul- R. Gilliam patent subsequent to July 30, 1990, Assistant ExaminerDo'ris L. Troutman has been disclaimed. 221 Filed: May 30, 1973 [57] 1 ABSTRACT A cast hmged art1cle and the method and apparatus PP 365,269 for simultaneously casting both parts of the article. A

Re'ated s Application Data first part of the article is formed with inner projec- [63] bummumiomim a" of Ser No 187 427 0c 7 tions, and a second part of the article is formed there- 1971 Pat NO 3p742 555 1 over to enclose the projections to provide a hinged 1 f 1 1 pivot. A staking unit which includes a punch then dis- [52] CL 16/171 torts the material in the first part adjacent the projec- [51] Int. Cl 1 1/06 tions so that the pivot will be freely movable [58] Field of Search 16/171 8 Claims, 18 Drawing Figures ll 1 I 1 24 1' l 1' 361 38" :j. "#38 3O I ,1! 50 li l 1. 26 1 40 PAIENTEU sac x 11974 SHEET '2 OF 4 PATENTEL 35B 1 3,854,166

SHEET l 0F 4 f 1 CAST HINGE This application is a continuation-in-part of my copending application Serial No. 187,427, filed October 7, 1971 now Patent No. 3,742,555.

BROAD STATEMENT OF INVENTION The present invention relates to a cast hinged article made by casting the parts of the article simultaneously to be pivotal on each other with the hinged pivot being treated to be freely movable.

DESCRIPTION OF THE PRIOR ART It is known in the prior art to east pivotal or hinged I elements to form an integral unit. An example of such casting is shown in US Pat. No. 2,819,494 issued on Jan. 14, 1958 to Louis H. Morin. In such prior art casting a pivot was provided that would allow one element to be rotated with respect to the other. However, in this type .of casting where a second element is formed over a prior formed element, a degree of binding is present so that the relative movement of the two elements is not freely rotatable. In the aforementioned patent this is not necessarily a disadvantage since a belt buckle is the product involved. However, for other elements,

- such as a hinge; where this type of casting process is utilized, movement of the pivot free of binding is desired.

DESCRIPTION OF THE INVENTION with the first element being distorted so that the pivot is freely movable.

A further provision of the-subject invention is the provision of connected elements forming a hinge wherein a first one of the elements is formed withprosion of the depression means provides a freely movable pivot area.

The nature of the present invention will become more clearly apparent and better understood from the jections and the other element is formed thereover to provide a pivot for thehinge, and depression means are formed in the first element to spread the projections to free the pivot.

A still further provision of the present invention is to I provide an articulated element formed between movable dies wherein one element is cast over another element to form a hinged area, and the connected ele ments are positioned between staking means that in- In a preferred embodiment of the invention an article is provided comprising articulated elements of which following description and accompanying drawings, in which:

FIG. 1 is an elevational view of the one side of the hinged article of the present invention showing the decorative formation thereon;

FIG. 2 is an elevational view of the other side of the hinged product showing the flat-sided formation and depressions formed therein;

FIG. 3 is a side view of the hinged product shown in FIGS. 1 and 2;

FIG. 4 illustrates the installation of the article shown in FIGS. 1-3;

FIG.'5 is a view similar to FIG. 2 showing a lower element of the formed article in enlarged form;

FIG. 6 is a perspective view of an upper element of the formed article;

FIG. 7 is a diagrammatic view illustrating the apparatus and method for forming the article shown in FIGS. 1-3;

FIG. 8 is an exploded perspective view of one opposed means that provides the distortion of the element shown in FIG. 5;

FIG. 9 is an exploded perspective view of another opposed means that provides the distortion of the lower element shown in FIG. 5;

FIG. 10 is a view of the opposed means shown in FIGS. 8 and 9 in assembled condition prior to contacting the formed article fora distortion step;

FIG. 11 is an elevational view of punch means located in the opposed means;

FIG. 12 is an end view of the punch means shown in FIG. 11; g

FIG. 13 is a plan view of shown in FIG. 11;

FIG. 14 is a perspective view of part of the end of the punch means showing raised areas thereon;

FIG. 15 is an elevational view of a modification of the embodiment of FIG. 2;

FIG. 16 is an elevational view of a modification of the embodiment of FIG. 5;

FIg. 17 is an elevational view of a further modificapart of the punch means tion of the embodiment of FIG. 5; and

. 22 as shown in FIG. 1 and a rear flat side 24 as shown in FIG. 2. The article illustrated is a decorative hinge although it is to be understood that the invention is not the first element isformed with projections around which the second element has been formed to provide a pivotal joint. The first element includes depression means formed therein which distort and spread the material in the area of the projections. In the embodiment illustrated a pair of spaced parallel depressions are formed in the first element to provide for the movement of the projections which releases any binding be tween the first and second elements. The article can be made in the form of a decorative hinge, and the incluto be so limited since the invention is considered to encompass any articulated element to be provided with a freely movable pivot. Front surface 27 of the hinge in cludes a decorative surface such as the illustrated embodiment of a fleur de lis pattern which includes part of the pattern formed as raised surfaces to provide the decorative effect which can be enhanced by polishing and finishing. Article20 includes a first cast hinge element or lower section 26 and a second cast hinge element or upper section 28. Element'26 is connected tions-similar to the projections 36.

with element 28 by a pivot or hinge means 30. As mentioned above, front surface 22 includes raised areas surfaces 36 formed on the facing surfaces of the extensions, as shown in FIG. 5, the projections extending inwardly toward each other in opposed relation. Each projection 36 is tapered (e.g., with frustoconical surfaces) so that its cross-section is smallest at its remote end. Upper element 24 is formed with an extension depending from the base or body of this member, the extension having a-pair of aligned recesses or enclosure areas 38 (e.g., with frusto-conicalsurfaces) on opposite edges as shown in FIG. 6, formed to fit respectively around the projections 36 to complete the hinge. The frusto-conical surfaces thus form bearing surfaces. FIG. 3 shows the upper element 28 in solid lines where it is aligned with lower element 26 so that the entire hinged 44 while the lower or smaller element 26 would be attached to the back side 48 of the box 44. It is important that the pivot 30 provide a freely movable relationship 1 between the elements so that top lid 46 does not bind and is easlily rotated foropening and closing, The novel decorative hinge of the invention could also be-used on louvered doors or cabinets or similar structures, andit is understood that the size and thickness of the hinge could be varied depending upon the strength required and the size of the structure involved. Similarly, the

decoration could be changed and other designs utilized article 20 is flat while the dotted line position of element 28 in FIG. 3 illustrates a pivoted position around hinge means 30. As will be apparent in the following disclosure,'each of the elements 24 and26 are cast elements, with one of these elements being initially-cast and forming a portion of the mold surface for the second element, i.e., in the region of the bearing surfaces- In this manner of forming the article, a tight fitcan ,occur between the elements on their adjoining surfaces, which may interfere with free pivotal movement at the pivot joints. The article, formed in this manner, thus does not require any further assembly of the elements. The projections 36 extend into the enclosure areas 38 a sufficient distance that, this being a cast article, the elements cannot be separated without destruction of the article. Similarly, it'is apparent that separate first and second elements cannot be assembled without destruction of the article. It is further to be pointed out that, while it is preferred that the projections 36 and enclosure areas 38 be provided on the respective elements 26 and 28 as illustrated in FIGS. 5 and 6, it is apparent that the respective positions of the projections 36 and enclosure areas 38 may be reversed. In other words, the element 26 may be provided with enclosure areas, and the element 28 may be provided with projec- A pair of spaced holes 40 are formed in lower element 26. The particular spacing, number and location of holes 40 is not a critical feature of the invention as long as these holes are sufficiently spaced apart to re ceive screws, nails or other fastening means for holding the article in place when installed. Similarly, a pair of spaced holes 42 are. provided in the upper element 28 for the same purpose of receiving similar fastening means for installation. Although four holes are illustrated, it is to be understood that more orless than four holes could be utilized for fastening an article such as the decorative hinge illustrated to the structure where it is utilized.

FIG. 4 illustrates a typical installation of article 20 as a hinge for a container such as ajewelry box 44. A typical decorative hinge for this purpose would be approximately l-2 inches in length and'the upper or larger element 28 would be attached to the top lid 46 of the box as long as the freely movable pivot feature is present.

The freely movable feature of the pivot is provided by a compressed region or depression means 50 formed in the first element 26. As most clearly seen in FIG. 5, depression means 50 comprises a pair of spaced, parallel, elongated depressions 52'and 54 that extend longitudinally in element 26 with each depression respectively aligned generally with a projection 36 and preferably normal to the pivotalaxis, as illustrated. Depressions 52 and 54 are formed by a punch orsimilar device being forced into element 26 to thereby spread the material in the area around each projection 36. Accordingly, it will be appreciated from a consideration of FIG. 5 that depressions 52 and 54 provide a distortion of the material around each of projections 36 so that they will pivot freely within enclosures 38 of pivot hinge 30. In other words the material of the element is distorted in a direction'tending to separate the extensions on member 26 from their cast positions, and hence to loosen the pivot joint.

While the hinge member 26 as illustrated in FIGS. 2 and 5 is shown as being provided with two parallel depression means 50, it will be apparent that the number, type and size of such depression means can be varied depending, for example, on the form of the hinge itself and the material of which the hinge is made. Thus, in

.the dimensions of the article are such that it would be more difficult to provide two such depressions aligned as shown in FIGS. 2 and 5. Furthermore, it is apparent that more than two parallel depression means may be provided if desired, for example, with larger size hinges, and also when the metallurgical characteristics or shape of the hinge structure limit the spreading that can be effected in a practical manner only by two such depressions.

In addition, while the depressions illustrated in FIGS. 2 and 5 are shown as being spaced from the pe= rimeter of the hinge member 26, this depiction of the depression means is not intended to be limiting, since if desired, the depression means may extend to the pe rimeter of the hinge member 26 as shown in FIG. 15,

in exaggerated form, and thus in an actual structure the depression may be only barely visible. For example, a large punch may be employed to effect the general spreading of the material in the central portion of the hinge member coextensive with the region aligned with the projections 36 and the region therebetween. A die member for effecting such'spreading may, if desired, be smoothly rounded whereby-a general concavity is produced in the hinge member 26 instead of the discreet linear depression means as illustrated in FIGS. 2 and 5,

The casting apparatus of the invention is shown scheulated relation therewith is shown in aforementioned U.S. Pat. No. 2,819,494. This is provided by having die 60 and a mating die relatively movable toward and away from each other to allow the vertical movement of the elements being formed in sequential steps. During the formation heated material from an injection nozzle (not shown) flows into a gate 62 in the direction shown by arrow A. The heated material flows around a transfer core pin 64 to form a ring-like upper gate portion 66 and a lower gate portion 68. It is to be appreciated that this is a known feature to flow the heated metal into molds formed in mating diesto simultaneously form upper and lower elements in articulated form. In the upper part of the die60 the gate 66isseen to include paths 70 and 72 arranged todirect separate flows obliquely with respect to each other to completely form one lower element 26. Simultaneously with the flow into gate 66 there is also a flow intolower gate 68 to form the upper or second element 28 in articulated condition with a previously formed lower element that hasbeen transposeddownwardly. This is provided by flow paths 74 and 76 located obliquely with respect to each other to disperse the heated material throughout the mold in forming element 28. The articulated formation is correlated with openingand closing of the dies so that just prior tothe material flowing step, the movable dies had been separated and the transfer core pin 64 had moved the previously formedelement 26 down to the lower position where it is shown in'FlG. 7 as element 26. Accordingly, it isto be understood that each time the heated material flows into gate 62 and through portions 66 and 68 into the molds, a first or lower element 26is formedin theupper position and The staking step is an important feature of the present invention, and the staking location is located directly below movable die so that the articulated elements 26, 28 in solid form that form a completed hinged article are moved downwardly thereto by the intermittent vertical movement of the transfer core pin 64. The staking step is for the purpose of treating the first or lower element now indicated as element 26" so that its projections 36 will be freed from binding within the enclosures 38 located in element 28'. It is in this staking location that element 26" is subjected to a staking or punching deformation of the material in the central area of the element toform the depression means 50. The type of material that is supplied in the heated form to be solidified isa zinc alloy which is known as Zamak No. 3. However, the invention is not to be con sidered to" be limited to a zinc alloy. as any material of similar nature can be used which is capable of being melted and injected in the flowable form to be solidified in the mating molds.

The staking or punch operationwill now be described, and it is to be noted that the staking location is just below and closely adjacent to the forming molds so that the solidified elements 26" and 28' are still in a heated condition allowing the depressions and spreading of the metal to be easily performed.

FIGS. 8 and 9 illustrate the elements that form the staking unit which arepositioned in opposed relation as shown in FIG. 10'. The hinged article shown as elements 26 and 28' that is to be staked or punched is moved intothe lower position as shown in FIG. 10 between opposed units 80 and 82 that are movable toward each clud'es the decorative ornamentation. For this purpose opposed unit 80' includes an outer cover or housing 84 which includes horizontally spaced parallel bores 86 and 88 for including therein stiff compression springs 90 and 92. respectively. The right-hand surface of a completed hinged article is formed in the lower posi- 1 tion by element 28 being cast with itslower enclosure portions 38 molded around solidified projections 36-.

It will also be seen in FIG. 7 that when first element 26 representingthe lower half of the hinged article has moved downward to where it appears as a solidified element 26, then gate'elements 62, 66 and-"68appear as solidifiedgate elements 62 66 and-68. t

It will further be appreciated from an examination of FIG. 7 that when element 26 moves-to its first-lower position wherelit appears as solidified element 26" that an element 28 that had beenpreviously formed then 'moves to a further lower or staking position where it appears as solidified element- 28 where it is seen to be in articulated connection with a solidified first-element 26' that had been previously. formed an'dmoved downwardly to the staking position.

housing 80 that includesthe bore openings 86 and 88 is formed with a notched or depressed area 94 that is oblong in shape as shown in FIG. 7'to include the open-' ings of bores 86 and 88 and be substantially of the same size as the hinged article 20. Within the notched area 94* is fitted one end 96 of a trim punch 100 which includes a raised portion 10-2 on its other end that issubstantially of the same size and shape as the front surface of hinged element 20. From a consideration of FIG. 8 it willbe seen that trim punch 100 includes the oblong shaped end portion 96 that fits within slot 94, a section 104 that extends from end- 96- and has a similar but slightly smaller oblong shape with its top surface aligned with the top surface of end portion 96', the

raised portion 102 which includes upper and lower parts 106 and 108 of generally the same configuration as the entire front surface 22, and a recessed groove around so that part of a backsurface of cover 112 is pressed against a-flat-surface l 03 'whichis the frontsurface of end 96 that contacts extended portion 104. Cover 112 and housing 84 have a generally rectangular shape although this is not an essential feature of the invention. Cover 112 further includes a depressed area i 116 in the form of three connected legs shaped to receive the solidified gates 62', 66 and 68 when they have been moved into the staking location. Accordingly, depression 116 has generally the same shape as the gate portions shown in FIG. 7 and the trimming of the gate portions from the hinged product 26", 28 is provided at this position.

Opposed means 82 includes housing 120 which is shaped similarly to housing 84 and includes horizontally spaced parallel bores 122 and 124 terminating in openings 126 and .128 within which stiff compression springs 130 and 132 are respectively located. On the surface of housing lfacing hinged product 26", 28' a recessed area 134 is formed which is oblong in shape and substantially'of the same size as the hinged product 26", 28 and further includes the openings 126 and 128 as shown in FIG. 9.

A second contacting part of trim pad 140 is provided which includes an end 142 of such oblong size that fits within recessed area 134. Trim pad 140 is seen in FIG. 9 to include the oblong end section 142, and a raised portion 144 is-formed thereon in a shape of generally the same size and corresponding to the shape of the hinged product. The surface of portion 144 is positioned to contact the back surface of the hinged product and is generally flat to correspond with surface 24 as shown in FIG. 2. It will be noticed in FIG. 9 that the top surface of raised area 144 is generally in line with the top surface of end 142, but end 142 extends further .downwardly than area 144 in order to receive a cover on a flat surface 146 that is formed on a front side of end 1'42.v

- A cover 150 fits around trim pad 140 and against the inner surface of housing 120. Cover 150 includes a centrally located cut-out portion 152 which is generally of the same shape as raised portion 144 so as to fit thereabout with the rear surface of cover 150 abutting flat surface 146 as well as the inner surface 129 of housing 120. It will be seen in FIG. 9 that cover 150 includes a cut-out portion 152 that extends into the upper surface of cover 150 to form a notched opening 156 to accommodate the upper tip of hinged product 26", 28' in the position shown in FIG. 9. Cover 150 also includes a depression 154 that is in the general shape of the gate portions 62', 66 and 68. It is to be understood that depression 154 corresponds in opposing location and shape with depression 116 to enclose the gate portions to provide for trimming and removal thereof from the cast product.

It will be noted in FIGS. 9 and 10 that an opening 146 is provided in the lower part of trim pad 140. A corresponding opening 158 is formed in the rear of housing 120 so that a punch 160 can be slidably positioned therein as shown in FIG. 10. It will be noted that punch 160 as well as housing 120 and cover 150 have a generally rectangular shape, but this is not a critical feature of the invention.

The function of punch 160 is to provide the staking operation wherein the punch is acted upon at one end by means not shown which would pass opening 158. The other end of punch 160 is thereby driven into the back of element26" to form. depressions 50 as described hereinbefore to spread the material and free the pivot. I

As seen in FIGS. 11-14 punch 160 is an elongated member with a generally square shape in cross section and includes chamfered edges 162 along its elongated edges. Punch 160.has an end 164 that is forced into the lower element of product 20. End 164 includes a pair of parallel raised areas 166, and the punch and raised areas are formed of a material sufficiently hard,- such as hardened tool steel, to press into the lower element 26" without deformation of the punch or raised areas. As mentioned previously, the forcing of raised areas 166 into the lower element is facilitated since the product is still in the heated condition from the molding operation.

} Each raised area 166 has a particular configuration to facilitate entry and spreading of the material in order to free projections 36 from enclosures 38. As most clearly seen in FIG. 14, each raised area 166 includes an inner surface 168 projecting perpendicularly from the end 164 of punch 160. Surface 168 extends on the order of 0.02 inches and then is curved outwardly to form a curved surface 170 terminating adjacent the respective chamfered edges and outer side of the punch.

The radius of the curved surface 170 is approximately 0.05 inches measured from the outer edge of surface 168. It is an important feature of the invention to have curved surface 170 so that the penetration by raised areas 166 is first achieved along the outer edges 172, and the continued penetrating movement of the punch causes the material to spread outwardly because of the curved surface 170. The spacing of each raised area 166 from each other is not a cirtical feature of the invention as long as such spacing is in general alignment with the particular location of the projections 36 so that the spreading of the alloy material is effective to move the projections into freely pivotal movement with respect to enclosures 38. The actual spread or deformation of the material is about 7- 10 mils.

When the contact is made by opposed units '80 and 82 being pressed against the opposite side of hinged product 26", 28, punch 160 is driven by the means not shown so that the raised areas 166 are forced into the back of lower element 26" to spread the material and provide the free pivotal motion. With this driving or staking step the springs 90, 92 and 130, 132 provide a resilient support for the contacting parts and so that a small amount of movement of "give" is permitted with respect to parts 100' and 140.

While the punch as illustrated in FIGS. ll-l4 is provided with two raised areas 166 for spreading of the material in the hinge member, it will be apparent that the punch may be provided with any number of projections depending upon the design of the hinge as above discussed. For example, when a single depression means is to be provided in the hinge member 26 as shown in FIG. 16, the punch will of course be provided with a single projection, the sides of the projection being shaped to effect the spreadingof the material in opposite directions, for example with curved surfaces I as illustrated in the outward sides of the projections 166 in FIGS. 13 and 14. Similarly, when the spreading of the projections 36 is to be effected by a larger area punch, to provide the modification of FIGS. 17 and 18, the punch may have a generally convex cross section to effect the general movement of the material from the center of the hinge member without forming the discreet depression mark. The invention thus contemplates the compression or punching of the central portion of the hinge member whereby material in the central portion or bridge area of the hinge member 26 is outwardly forced to effect the spreading of the projections 36. It will further be apparent that the invention also encompasses spreading of the hinge member in the event that the hinge is formed with the projections and enclosure areas in opposite relative positions as compared with the hinge shown in FIGS. 2, and 6, i.e., with outwardly extending projections on the hinge member 28 replacing the enclosure areas 38 and adapted to mate with enclosure areas on the hinge member 26 replacing the projections 36.

From the above description it is clear that the present invention discloses a novel articulated or hinged element wherein one element has depressions formed therein to spread the projections forming the hinge for free movement.

Another feature of the present invention is the provision of the casting apparatus for the articulated elements which includes staking or punch means that provides opposed units for contacting the articulated elements so that the punch can cause the distortion or spreading of the material for the freeing of the pivot.

A further feature of the present invention is the method of casting the article whereby the articulated elements are moved into the staking position, and the punch means are driven into one of the elements to spread the material for the loosening and freemovement of the pivot.

It will be understood that various modifications and changes may be made by those skilled in the art in the particular features of the article, apparatus and method which has been described above for illustrative purposes without departing'from the scope of the invention as defined by the following claims.

What is claimed is: e i

1. An article having a first element, first and second parallel extensions depending from an edge of said first element, first and second bearing means on said first and second extensions, the bearing means being aligned and directed toward each other,

a second cast element, extensionmeans depending from an edge of said second cast element, third and fourth aligned bearing means on said extension means and being directed away from each other, and engaging said first and second bearing means respectively to form an articulated joint,

the respective bearing means being sufficiently overlapped to prevent non-destructive assembly and disassembly of said first and second elements,

saidfirst element having a compressed region between said first and second extensions in which the material of the first element is distorted'in a direction tending to separate said first and second extensions. 2. A hinge having first and second hinge elements, said first element having a first base with a flat side,

a pair of first parallel spaced apart extensions depending from an edge of said base, and aligned first bearing surfaces on said extensions and integral therewith, the first bearing surfaces being on facin sides of said first extensions,

said second element having a second base with a second extension depending from an edge thereof, and a pair of aligned second bearing surfaces on opposite edges of said second extension and cast integrally therewith,

said elements being assembled with each first bearing surface engaging a second bearing surface, to form pivot joints, one bearing surface at each joint being in the form of a recess and the other bearing surface at each respective joint being in the form of a bearing projection extending into the respective recess a distance sufficient to prevent nondestructive assembly and disassembly of the first and second elements,

said first element further having a punch formed depression in said flat side between said first extensions which distorts the shape of said first element,

said depression being positioned to relatively displace said tirst bearing surfaces in opposite direc- I tions, whereby the pivot joints are loosened.

3. The hinge of claim 2 wherein said bearing surfaces are frusto-conical.

4. The hinge of claim 2 wherein said punch, formed depression is a slot in said flat side extending in a direction normal to the pivot axis of said hinge elements.

5. The hinge of claim 2 wherein said punch formed depression comprises a pair of parallel slots extending in said flat side in a direction normal to said pivot axis, said slots being generally aligned with separate pivot joints.

6. The hinge of claim 2 wherein said punch formed depression comprises a single depression extending substantially the distance between said first projections in said first base.

7. The hinge of claim 6 wherein said depression is formed substantially without discreet edges on the adjoining undistorted surfaces of said flat side.

extensions.

Claims (8)

1. An article having a first element, first and second parallel extensions depending from an edge of said first element, first and second bearing means on said first and second extensions, the bearing means being aligned and directed toward each other, a second cast element, extension means depending from an edge of said second cast element, third and fourth aligned bearing means on said extension means and being directed away from each other, and engaging said first and second bearing means respectively to form an articulated joint, the respective bearing means being sufficiently overlapped to prevent non-destructive assembly and disassembly of said first and second elements, said first element having a compressed region between said first and second extensions in which the material of the first element is distorted in a direction tending to separate said first and second extensions.

2. A hinge having first and second hinge elements, said first element having a first base with a flat side, a pair of first parallel spaced apart extensions depending from an edge of said base, and aligned first bearing surfaces on said extensions and integral therewith, the first bearing surfaces being on facing sides of said first extensions, said second element having a second base with a second extension depending from an edge thereof, and a pair of aligned second bearing surfaces on opposite edges of said second extension and cast integrally therewith, said elements being assembled with each first bearing surface engaging a second bearing surface, to form pivot joints, one bearing surface at each joint being in the form of a recess and the other bearing surface at each respective joint being in the form of a bearing projection extending into the respective recess a distance sufficient to prevent non-destructive assembly and disassembly of the first and second elements, said first element further having a punch formed depression in said flat side between said first extensions which distorts the shape of said first element, said depression being positioned to relatively displace said first bearing surfaces in opposite directions, whereby the pivot joints are loosened.

3. The hinge of claim 2 wherein said bearing surfaces are frusto-conical.

4. The hinge of claim 2 wherein said punch formed depression is a slot in said flat side extending in a direction normal to the pivot axis of said hinge elements.

5. The hinge of claim 2 wherein said punch formed depression comprises a pair of parallel slots extending in said flat side in a direction normal to said pivot axis, said slots being generally aligned with separate pivot joints.

6. The hinge of claim 2 wherein said punch formed depression comprises a single depression extending substantially the distance between said first projections in said first base.

7. The hinge of claim 6 wherein said depression is formed substantially without discreet edges on the adjoining undistorted surfaces of said flat side.

8. The hinge of claim 6 wherein said depression extends to the edge of said first element between said first extensions.

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