Background and Field of the Invention This invention relates to a pinless hinge mechanism.

A traditional hinge includes a pair of hinge halves with each hinge half including a wing section and a half channel coupled to the wing section. When the half channels of the hinge halves are aligned, the half channels forms a pivot channel for receiving a separate pivoting pin. When the wing sections are attached to respective objects or structures, such as a door and a door frame, this enables the structures to move pivotably with respect to each other about the pivoting pin.

However, such traditional hinges have a number of separate parts resulting in more costs and assembly time.

Further, in the field of electrical science, traditional hinges are not suitable for use with enclosures for storage of electronic components because traditional hinges are unlikely to meet Electromagnetic Compatibility (EMC) requirements.

It is an object of the present invention to provide a pinless hinge mechanism, which alleviates at least one of the disadvantages of the prior art and/or to provide the public with a useful choice. Summary of the Invention

In accordance with a first aspect of the present invention, there is provided a pinless hinge mechanism comprising an engagement member; and a leadthrough integrally formed with a support member, the leadthrough comprising protrusion member having a closed end, the protrusion member with its closed end being insertabie into the engagement member for creating a pivotal connection therebetween. 4

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"Pinless" in this application means the pivotal connection between Jhe door and body is formed without a separate pin. Since the "pin" function is performed by the protrusion element of the lead-through which is integrally formed with the support member, this obviates a separate pin or barrel to create the pivotal movement. In this way, the pivotal connection is created without additional component and a separate pin is not needed. The hinge mechanism may thus be considered "pinless".

By having a "closed end" protrusion member, this may provide more rigidity to the pivotal connection and helps the leadthrough meet EMC requirements, especially when the pinless hinge mechanism is used in an enclosure for storing electronic components.

Preferably, the engagement member is formed with a connection member, which is connectable to a first article. The support member may be connectable to a second article.

In the alternative, the engagement member may form part of a first article; and the support member forms part of a second article.

Preferably, the lead-through further includes an embossed base for supporting the protrusion member. In the alternative, the engagement member may include an embossed portion surrounding an extruded hole for receiving the protrusion member.

The engagement member may include a support plate having an extruded hole arranged to allow the protrusion member of the lead-through to protrude therethrough. The engagement member may further include a raised peripheral wall arranged to surround the entire extruded hole. In this respect, the pinless hinge mechanism may further comprise a locking mechanism to releasably lock the lead-through to the engagement member. Preferably, the engagement member further includes a raised peripheral wall arranged to partially surround the extruded hole. The support plate may further include an opening which extends from a first end of the support plate to the extruded hole, the opening being configured to allow the protrusion member of the lead-through to slide to the extruded hole. The pinless hinge mechanism may further comprise a bridge member arranged across the opening. Preferably, the support plate includes a stopper wall at a second end arranged to adhere to the locking mechanism. The stopper wall may include two spaced apart extruded guides. Specifically, the locking mechanism may include a leaf spring having a pivot end arranged to be fixedly mounted to the support plate. The leaf spring may include a second end having an angled abutment portion and a finger plate connected to the abutment portion, the finger plate being used to pivot the leaf spring about the pivot end. Preferably, the leaf spring includes a centre aperture arranged to receive the protrusion member and the raised peripheral wall.

It should be appreciated that the pinless hinge mechanism may be used in many applications. For example, the pinless hinge mechanism may be used as part of an enclosure or more specifically, a storage enclosure for electronic devices. Further, the pinless hinge mechanism may be used as a hinge for a door, pivoted tray or platform etc.

In accordance with a second aspect, there is provided a method of assembling an enclosure from a plurality of covers to define a storage compartment, and a door for the storage compartment, the plurality of covers including first and second covers including a lead-through integrally formed with the respective first and second covers, the leadthrough comprising a protrusion member having a closed end, and the door including first and second support plates integrally formed with the door, each of the support plates including an engagement member, the method comprising

(i) engaging the engagement member with respective protrusion members of leadthroughs of the first and second covers to enable the corresponding engagement member and protrusion member to cooperate with each other to create a pinless hinge connection between the door and the first and second covers; and thereafter,

(ii) mounting the rest of the plurality of covers to the first and second cover to define a body for the storage compartment.

In accordance with a third aspect, there is provided a method of assembling an enclosure from a plurality of covers to define a storage compartment, and a door for the storage compartment, the plurality of covers including first and second covers, each having a lead- through integrally formed with the respective first and second covers, the leadthrough comprising a protrusion member having a closed end, and the door including first and„. second support plates integrally formed with the door, each of the support plates including an engagement member, the enclosure having a leaf spring with a pivot end fixedly mounted to respective support plates, the method comprising

(i) assembling the plurality of panels to form a body to define the storage compartment;

(ii) sliding the door towards the body to abut an abutment portion of the leaf spring against respective protrusion members;

(iii) pushing the door further towards the body to cause the leaf spring to pivot above the respective protrusion members until the abutment portion is clear of the respective protrusion members and for the protrusion members to be received within corresponding engagement members of the support plates thereby forming a pinless hinge connection between the respective extruded holes and leadthroughs.

Preferably, the method further comprises, to detach the door, pivoting the leaf spring until the abutment portion clears the respective protrusion member and withdrawing the door away from the body.

The invention may also relate to an enclosure formed from any of the above described methods.

It should also be appreciated that features relating to one aspect may also be applicable for the other aspects.

Brief Description of the Drawings

Examples of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of a first enclosure having a hinge mechanism according to a first embodiment of the present invention;

Figure 2 shows parts of the enclosure of Figure 1 being detached from each other to illustrate how the enclosure is assembled; Figure 3 is -a closed up view of portion A of Figure 2 to show the hinge .mechanism more closely;

Figure 4 illustrates steps for integrally forming a part of the hinge mechanism of Figure 3;

Figure 5 is an enlarged view of portion B of Figure 3;

Figure 6 is an enlarged view of portion C of Figure 3;

Figure 7 is a cross-sectional enlarged view of the hinge mechanism of Figure 1 ;

Figure 8 is a perspective view of a second enclosure having a lockable hinge mechanism according to a second embodiment of the present invention;

Figure 9 shows the second enclosure's door being detached from the enclosure of

Figure 8;

Figure 10 is a closed up view of portion D of Figure 9 to show the lockable hinge mechanism more clearly;

Figures 11 and 12 illustrate a locking mechanism for locking the lockable hinge mechanism of Figure 9;

Figure 13 shows how to attach the door of the second enclosure of Figure 9;

Figures 1 a and 14b are cross-section views of the second enclosure of Figure 9 in the direction EE to illustrate how the locking mechanism of Figure 11 operates to lock the lockable hinge mechanism;

Figure 15 is a closed up view to illustrate how the locking mechanism of Figure 11 locks the lockable hinge mechanism of Figure 10;

Figures 16a and 16b illustrate how to detach the door from the enclosure's body starting from the position illustrated in Figure 14a;

Figure 17 illustrate a final step to detach the door from the enclosure's body (partially shown);

Figure 18 includes Figure 18a which is a closed up perspective view of the locking mechanism of Figure 12, and Figure 18b which is a cross-sectional side view of Figure 18a in the direction J-J, before the flaring process.

Figure 19 includes Figure 19a which shows the side view of the locking mechanism of Figure 12 after the flaring process, and Figure 19b which shows a closed-up perspective view of the locking mechanism similar to that illustrated in Figure 18a, also after the flaring process; and Figures 20 to 22 show a hinge mechanism which is a variation of the hinge mechanism of Figure 3.

Detailed Description of Preferred Embodiments

Figure 1 is a perspective view of a first enclosure 1000 according to a first embodiment of the present invention. The enclosure 1000 includes a housing 1100 having a box body 1200 defining a storage compartment 1300 and a door 1400 for closing the storage compartment 1300.

The housing 1100 is made of sheet metal and in this embodiment, the housing 1100 includes a bottom cover 1106, a top cover 1108, two side covers 1102,1104 and a back cover 1110 arranged orthogonally with each other to form the box body 1200. The housing 1100 further includes a door panel 1402 for the door 1400.

Figure 2 shows the covers 1102,1104,1106,1108,1110,1400 or panels detached and separated from each other to illustrate how the enclosure 1000 is assembled. Each of the side cover 1102,1104 includes a planar body 1102a, 1104a and an inwardly extending peripheral flange 1102b,1104b orthogonal to the planar body 1102a, 1104a. The peripheral flanges 1 102b, 1104b allow the bottom cover 1106, the top cover 1108 and the back cover 1110 to be attached to the side covers 1102,1104 to form the box body 1200 using known attachment means, for example, rivets or screws.

The enclosure 1000 includes a hinge mechanism 1500 integrally formed with the housing 1000. In the first embodiment, the hinge mechanism 1500 includes lower and upper sets of engagement members 1510,1550. The lower set of engagement members 1510 is formed between a lower inner corner 1404 of the door 1400 and the bottom cover 1106 and the upper set of engagement members 1550 is formed between an upper inner corner 1405 of the door 1400 and the top cover 1108. Both sets of engagement members 1510,1550 are structurally similar and the lower set of engagement members 1510 will be described with reference to Figure 3 which is an enlarged view of portion A of Figure 2 and it would be appreciated that the upper set of engagement members 1550 is formed in a similar way. The lower set of engagement members 1510 includes first .. and second, engagement members 1512,1520 arranged to cooperate with each other to define a pivotal connection. The pivotal connection provides a fixed axis of rotation to enable the door 1400 to be pivotably coupled to the body 1200 (via the top and bottom covers 106,1108). Since there is no separate pin or barrel to create the pivotal connection, the hinge mechanism 1500 may be considered as "pinless".

In this embodiment, the first engagement member 1512 includes a raised lead-through or "round draw" 1512 shown more clearly in Figure 6 integrally formed with a support member which is the bottom cover 1106. Figure 4 shows the steps of forming the lead-through 1512 using a die and punch (not shown) whose shapes are adapted to create the shapes of the result of each step. At step 400, the raised lead-through 1512 and an initial protrusion element 1516' is formed using a single process by punching the bottom cover 1106 which also creates an embossed portion 1514 for carrying the initial protrusion element 1516'. At step 402, the initial protrusion element 1516' is shaped to form an intermediate protrusion element 1516" and finally, at step 404, the intermediate protrusion element 1516" is further shaped to form a circular protrusion member 1516 as shown in Figure 6 carried by the embossed portion 1514. In this way, the lead-through 1512 is integrally formed with the bottom cover 1106. As it can be appreciated, the circular protrusion member 1516 is formed with a closed end 1518 i.e. it is not a through hole or is not opened.

The second engagement member 1520 includes a support plate or door flap 1406 (see Figure 3) and an extruded hole 1522 shown more clearly in Figure 5. The door flap 1406 is integrally formed with the door panel 1402 of the door 1400 and thus, the door flap 1406 is made from the same material as the door panel 1402. The door flap 1406 is substantially rectangular in shape and is bent orthogonal to the door panel 1402 so that the door flap 1406 extends into the storage compartment 1300 when the door 1400 is closed. The enclosure 1000 further includes gussets 1408 which add structural strength to a joint 1409 between the door flap 1406 and the door 1400. Instead of being integrally formed with the door panel 1402, the door flap 1406 (with the extruded hole 1522) may be formed separately and independently from the door panel 1402 and then connected to the door panel 1402.

The extruded hole 1522 is extruded from the door flap 1406 to create a raised circular wall 1524 and its size and shape is configured to receive the protrusion member 1516 of the raised lead-through 1512. When the protrusion member 1516 of the lead-through 1512 (with the closed end 1518) is inserted into the extruded hole 1522 as shown in Figure 7, the raised circular wall 1522 engages the protrusion member 1516 to create a fixed axis of rotation about a hinge axis 1570 which is a common concentric axis of the extruded hole 1522 and the lead-through 1512. In other words, the protrusion member 1516 is inserted into the extruded hole 1522 to create a pivotal connection.

From Figure 7, it can be appreciated that the height of the raised circular wall 1524 of the extruded hole 1522 may be represented by H1 which may be about 2 times thickness of the sheet metal for forming the door flap 1406. Further, the height of the lead-through 1512 may be represented by H2 which may be about 4 times the thickness of the sheet metal for forming the lead-through (i.e. the thickness of the bottom cover i 106).

Since the protrusion member 1516 has the closed end 1518, this gives more rigidity to the lead-through 1512 and thus the pivotal connection is more reliable. Further, such a pivotal connection with the lead-through 1512 is more likely to comply with EMC requirements. The embossed portion 1514 functions as a spacer and improves the pivotal connection.

During assembly of the enclosure 1000, the lead-through 1512 is engaged with the extruded hole 1522 prior to attaching the various covers 1102,1104,1106,1108,1110 together. Referring to Figure 2 again, this means that the door 1400 is first attached to the lower cover 1106 and to the top cover 1108 by inserting the lead-throughs 1512 into respective extruded holes 1522 of the lower and upper sets of engagements members 1510,1550. This thus forms the pivotal connection along the hinge axis 1570 between the door 1400 and the body 1200 of the enclosure 1000, more specifically between the door 1400, and the top and bottom covers 1106, 1108.

Next, the side covers 1102,1104 are aligned with edges of the bottom cover 1106, the top cover 1108 and the back cover 1110 and fastened together to form the enclosure 1000. The first embodiment is particularly useful for enclosures where the door 1400 does not need to be detached for servicing or maintenance purposes since if detaching of the door 1400 is desired, this may require disassembling the enclosure 1000. It should be appreciated that the protrusion member 1516 of the lead-through 1512 functions as a pivot pin and the protrusion member 1516 cooperates with the extruded hole 1522 to enable the door 1400 to rotate about the hinge axis 1570 with respect to the body 1200 of the enclosure 1000 and since the lead-through 1512 (and thus, the protrusion member 1516) is integrally formed with the body 1200 of the housing 1100(more specifically, the bottom and top covers 1106,1 08), this obviates a need for a separate pin or barrel and thus, reduces costs and assembly time.

It should also be apparent that with the door 1400 assembled to the enclosure 1000 during assembly of the enclosure 1000, this provides simplicity in the assembly process, especially since no additional component or extra part is required to form the hinge mechanism.

Figure 8 is a perspective view of a second enclosure 2000 according to a second embodiment of the present invention. The second enclosure 2000 is similar to the first enclosure 1000 of the first embodiment except for the hinge mechanism 1500 and the door flap 1406 of the door 1400. In this embodiment, the second enclosure 2000 includes a lockable hinge mechanism 2500 and like parts between the first and second embodiments use like reference numerals except the first numeral for the second embodiment starts with "2" instead of "1" for the first embodiment.

The second enclosure 2000 includes housing 2100 having a box body 2200 structurally the same as the box body 1200 of the first enclosure 1000 and which also defines a storage compartment 2300. In the second embodiment, there is no need to disassemble the box body 2200 to attach a door 2400 to the box body 2200 and this is due to the lockable hinge mechanism 2500, which is integrally formed with the housing 2100. In the second embodiment, the lockable hinge mechanism 2500 includes lower and upper sets of engagement elements 2610,2650 as shown in Figure 9. Since both sets of engagement elements 2610,2650 are structurally similar, the lower set of engagement element 2610 is discussed in further detail with reference to Figures 9, 10, 11 and 12.

Just like the first embodiment, the lower set of engagement element 2610 of the second enclosure 2000 includes a lead-through 2512 having a raised profile 2514 and a protrusion member 2516 having a closed end 2518 formed at a bottom cover 2106 of the enclosure 2000. The lead-through 2512 is also integrally formed with the bottom cover 2106. Just like the first embodiment, the top cover 2108 also includes a lead-through 2530. Instead of the door flap 1406, the lower engagement element 2610 includes a support plate in the form of a support lug 2410 at a lower inner corner of the door 2400. The support lug 2410 is integrally formed from the door 2400 just like the door flap 1406 of the first enclosure 1000 and includes gussets 2408 formed at the joint 2409 to strengthen the joint 2409 between the door 2400 and the support lug 2410. The support lug 2410 has a planar body 2414 and a stopper wall 2416 at one end 2414a of the planar body 2414. The stopper wall 2416 is bent at an angle with respect to the planar body 2414 of the support lug 2410. The stopper wall 2416 includes two spaced apart extruded guides 2418 (see Figure 1 1) which are circular in shape. At the other end 2414b of the planar body 2414, the support lug 2410 includes an extruded hole 2526 which opens up into a wider opening 2424 at the other end 2414b. The extruded hole 2526 includes a semi-circular wall 2528 shaped to cooperate with the protrusion member 2516 of the enclosure body 2200. The wider opening 2424 enables the protrusion member 2516 of the lead-through 2512 to slide into the wider opening 2424 and to abut against the semi-circular wall 2528.

The support lug 2410 further includes a raised bridge member 2426 extending across the wider opening 2424 and the bridge member 2426 is used to engage with a locking mechanism.

As shown in Figures 9 and 10, the locking mechanism in the second embodiment is in the form of a leaf spring 2700 having a substantially flat body 2702 with a pivot portion 2704 bent at an angle with respect to the flat body 2702, a free end portion 2706 and a centre aperture 2708 having an engagement edge 2710 near the end portion 2706. The centre aperture 2708 includes a width for receiving the protrusion member 2516 of the lead-through 2512 and this will be elaborated below. As shown in Figure 11, the pivot portion 2704 includes two circular openings 2712 configured to receive respective extruded guides 2418 of the support lug 2410. The second bent end portion 2706 includes an angled abutment portion 2713 and a finger plate 2714. The angled abutment portion 2713 extends at an acute angle with respective to a longitudinally axis of the flat body 2702. and the finger plate_2714, when at rest, extends in a direction substantially parallel to the longitudinally axis of the flat body 2702. To attach the leaf spring 2700 to the support lug 2410, the flat body 2702 is arranged on top of the support lug 2410 and the extruded guides 2418 are inserted into the respective circular openings 2712 and this enables the leaf spring 2700 to be aligned with the support lug 2410. Next, the leaf spring 2700 is fixedly attached to the support lug 2410 using a flaring process by joining the pivot portion 2704 to the stopper wall 2416 at the extruded guides 2418 and this is shown in Figure 12 and Figures 18 and 19. Figure 18 includes Figure 18a which is a closed-up view of the pivot portion 2704 and the stopper wall 2416 of the locking mechanism of Figure 12, and Figure 18b which is a cross-sectional side view from the direction J-J of Figure 18a, which illustrates the arrangement of circular openings 2712 of the pivot portion 2704 being received by the respective extruded guides 2418 of the stopper wall 2416 before the flaring process.

Edges 2418a of the extruded guides 2418 of the support lug 2410 are then bent outwards using a flaring tool so that the edges 2418a engages the pivot portion 2704 of the leaf spring 2700 and the end result is shown in Figure 19 which includes Figures 19a and 19b. In this way, the pivot portion 2704 of the leaf spring 2700 is fixedly connected to the stopper wall 2416 of the support lug 2410.

It should be appreciated that besides using the flaring process, other fastening means such as using rivets and screws may also be used.

With the leaf spring 2700 mounted to the support lug 2410, the door 2400 is ready to be attached to the body 2200 of the housing 2100. As shown in Figure 13, the door 2400 is first aligned to the body 2200 by first aligning the centre of the extruded hole 2526 with the centre of the protrusion member 2516 of the lead-through 2512. Needless to say, this is also performed for the upper set of engagement element 2650.

Figures 1 a and 14b are enlarged cross sectional views in the direction EE of Figure 13 but with the door 2400 moved closer to the body 2200 of the second enclosure 2000. As shown in Figure 14a, when the angled abutment portion 2713 of the leaf spring 2700 abuts against the protrusion member. 2516 of . the lead-through.2512, the door 2400 is pushed further with a bit more force to cause the free end portion 2706 to slide above the protrusion member 2516 as the leaf spring 2702 pivots about the pivot portion 2704 i.e. due to the joint formed between the pivot portion 2704 and the stopper wall 2416. When the door 2400 is further pushed inwards, the angled abutment portion 2713 slides over the protrusion member 2516 until the protrusion member 2516 protrudes through the centre aperture 2708 and this is also the position at which one side of the protrusion member 2516 abuts against the semi-circular wall 2528 and the other side of the protrusion member 2516 is latched to the engagement edge 2710 of the centre aperture 2708. This "locked" position is shown in Figure 14b and Figure 15. It should be appreciated that in this position, the angled abutment portion 2713 of the leaf spring 2700 sits between the protrusion member 2516 and the bridge member 2426.

With the above arrangement, the lockable hinge mechanism comprising the lead-through 2512 and the extruded hole 2526 formed at the support lug 2410 is thus locked in place by the leaf spring 2700. The fixed axis of rotation of the door 2400 with respect to the body 2200 of the enclosure 2000 is formed by the cooperation of the protrusion member 2516 of the lead-through 2512 and the semi-circular wall 2528 and perhaps partly by the engagement edge 2710 of the leaf spring 2700. Figures 16a and 16b illustrate how to "unlock" the hinge mechanism 2500. To detach the door 2400 from the body 2200 of the second enclosure 2000, a user lifts the finger plate 2714 upwards in the direction F shown in Figure 16a using his fingers until the engagement edge 2710 is clear of the protrusion member 2516 of the lead-through 2512 and the door 2400 is slide backwards in the direction G shown in Figure 16b for the angled abutment portion 2713 to sit on the top of the protrusion member 2516. The same actions are carried out for the leaf spring of the upper set of engagement element 2650 but it would be apparent that the finger plate for the leaf spring for the upper set of engagement element 2650 would be pushed downwards. Further movement of the door 2400 away from the body 2200 of the second enclosure 2000 in the direction G (see also Figure 17) drags the leaf spring 2700 away from the protrusion member 2516 and the door 2400 is subsequently detached from the body 2200 of the enclosure 2000. As it can be appreciated, the. second .embodiment is particularly_usefuLfor enclosures with __ doors which needs to be detached for servicing or maintenance purposes. An advantage of the described embodiments is that the hinge mechanisms and the leaf spring may be produced from the same material as the body of the enclosure and this obviates the need for other types of material being used. This can lead to reduction in manufacturing costs and process. Also, the detachable function is user-friendly and may be performed by hand, without use of additional tools such as screw-driver or spanner.

The enclosures 1000,2000 for both embodiments are particularly useful for storing electronic components or devices although they 1000,2000 may also be used for storing other things.

The described embodiments are not to be construed as limitative. For example, the embodiments describe the forming of lead-throughs 1512,2512 at the body of the housing and the extruded holes at the door to form the hinge mechanism but it is envisaged that the lead-throughs may be formed at the door and the extruded holes formed at the body. Also, in the second embodiment, other types of locking mechanisms may be used, not just the leaf spring 2700. Also, the hinge mechanism 1500 or lockable hinge mechanism 2500 may have other applications, not just for an enclosure. For example, the hinge mechanism may be used as a hinge for a door, a pivoted tray or a pivoted platform etc

Also, the hinge mechanism 1500 may not be integrally formed with the enclosure 1000. For example, the lead-throughs 1512,2512 may not be integrally formed with the bottom cover 1106,2106 of the enclosure 1000,2000, and the second engagement members 1520,2610 may not be integrally formed with the door 1400,2400. Instead, the lead-throughs 1512,2512 may be integrally formed with a support member (not shown) and which is connectable to another article by welding. The another article may be part of an enclosure or it may be some other product. Likewise, the second engagement members 1520,2610 (i.e. for forming the extruded hole 1522 or the support lug 2410 may be formed on a separate plate and not integrally formed with the enclosure 1000,2000 and the separate plate connected to a further article. The further article may be part of an enclosure or it may be some other product.

Also, the embossed portion 1514,2514 of the two embodiments may not be formed at the lead-throughs 1512,2512 but instead the embossed portion 1514,2514 may be formed at the second engagement member (i.e. at the extruded hole 1522 for the first embodiment). Figures 20 to 22 show a hinge mechanism 3000 which is a variation .of the hinge, mechanism 1500 of Figure 3. The hinge mechanism 3000 includes an engagement member 3100 which is a variation of the second engagement member 1520 of Figure 3 with an extruded hole 3102 having an embossed portion 3104 formed from a support plate 3106 and which surrounds the extruded hole 3102. As explained above, the support plate 3106 may form part of a larger article (for example a panel of an enclosure) or the support plate 3106 may be connectable to the larger article, for example by welding.

The hinge mechanism 3000 further includes an engagement element 3200 which is a variation of the first engagement member 1512 of Figure 3. The engagement member 3200 includes a lead-through 3202 but there is no embossed portion 1514 unlike that of Figure 3 or 6. The lead-through 3202 includes a protrusion element 3204 having a closed end 3206 to increase rigidity of the pivotal connection. The lead-through 3202 is integrally formed with a support member 3208, which may be part of a larger article (such as the bottom cover 1106 of the enclosure 1000) or the support member 3208 may be welded to the larger article.

Figure 22 shows the protrusion element 3204 and the closed end 3206 inserted into the extruded hole 3102 with part of the engagement member 3100 and the engagement element 3200 omitted to show the pivotal connection more clearly. In this way, the lead-though 3202 cooperates with the extruded hole 3102 of the engagement member to create the pivotal connection.

It should be appreciated that other methods commonly known in the art, such as die casting may be used to form the leadthrough 1512,2512,3202 and protrusion member 1516,2516,3204, which could result in the leadthrough 1512,2512,3202 and protrusion member 1516,2516,3204 being substantially solid rather than being hollow as depicted in the drawings.

Having now fully described the invention, it should be apparent to one of ordinary skill in the art that many modifications can be made hereto without departing from the scope as claimed.