Title of Invention

A COMBINATION LATCH MEANT TO MAKE THE FASTENING SYSTEM PERTAINING TO DOORS MUCH SAFER AND STRONGER

Abstract

When compared to dooi fastening, devices like venti bolt. Night latch, and Mortise latch the Aldrop latch is the safest, and strongest. But. the Aldrop latch in its existing fomi can be locked from outside thereby trapping the inmates inside further the \ndnerable padlock used to fasten the same can be broken easily. With the locking bolt in the engaged position the buglars know for sure that the premises is un-occupied. THE SOLUTION The combination latch is a modified Aldrop latch where even if the locking bolt is engaged from outside the same can be un-locked from inside by means of the common rod Unking the inner and outer handles. Further, the locking. system is enclosed in an integral housing and with the locking, bolt in the outer latch being fully encased in a housing one will be doubtful about the house being occupied.

Full Text

3. DESCRIPTION OF INVENTION: This invention relates to a safer and stronger method of fastening doors. Presently the most common mode of restricting entry into a premises is by using a Mortise lock, Vertibolt, Night latch or the age old Aldrop latch. When the Mortise latch is used the door looks very elegant and flush. However, when a mortise is made in the face of the door to fit the device it further weakens weakens that portion of the door where a mortise and tenon joint already exists. Hence, this method is unsafe. As for the Vertibolt it is fixed to main doors opening inwards. Here its two vertically operating dead bolts engage a corresponding receptacle fixed to the door frame (chaukat) by means of wood screws. However, here, if extreme force is used the chancers of the screws ( holding the receptacle) shearing is greater. Hence this method is also unsafe as the door swings open in the direction of the force exerted from outside. Now the night latch is fixed to inward opening main doors. When intended the Night latch engages and dead'locks, into a receptacle which is fixed to the door frame by means of wood screws. Here again with the door swinging inwards, along the direction of the force used from outside, the chances of the wood screws shearing and giving way is not impossible. Hence this method of securing the door is also unsafe, Considering all the aforesaid drawbacks of the Mortise latch, Vertibold and the Night latch the age old Aldrop latch seems to be a better option for the following reasons, This concept is used in many inwards opening main doors and its locking bolt directly engages a hole in the door frame (to a depth of over 3 inches) from outside. Here the door is directly interlocked to the door frame (chauket) which is firmly anchored to the wall and floor of the building. Further, the solid structure of the door frame with a cross sectional area of over four square inches offers maximum holding strength (in the e\ent of forced entry) to anything anchored to it. As the Aldrop latch is fixed lo the door at a point where the mortise and tenon joint already exist it further reinforces that portion of the joint. Considering all the aforesaid facts the Aldrop latch, without doubt, offers an absolutely leliable method of securing the Main door to the door frame (Chaukat). But this age old concept has this following drawbacks because its design has not kept pace with the devious ways of modern criminal minds for the following reasons: 1. In its existing form and with its inherent weakness the Aldrop latch is definitely not safe. Instances are not rare when the occupants of the premises have been trapped indoors by the culprits bolting the Aldrop from outside and putting on a padlock. Now with the occupants safely locked indoors (as there is no provision to disengage the Aldrop latch from inside the premises) the culprits dare to go about their job of burgling nearby shops and driving off with their vehicles. 2. With the locking bolt of the Aldrop latch in the engaged position and being exposed it sei"ves as a definite indication to the culprits that the occupants are av/ay. 3. The big gap between the exposed portion of the locking bolt and the door permits jimmying and prying open by means of crowbars and other implements. Under the circumstances the clamps in which the said locking bolt engages (in double doors) can be easily sheared away by the force applied. 4. Where padlocks are used, its dangling shackle can be wrenched apart by means of a crowbar used as a leverage. In the process the staple can also come apart. 5. Where Aldrop latches are used on double doors, the same is engaged only to a single clamp on the other door. As the said clamp is secured to the door by means of just two bolts it easily gives way when the door is forced inwards along the direction of the door swing. 6. As the Aldrop can be operated and deadlocked only from outside the premises a Night latch is also used to dead lock the door from inside during nights. The principle object of this invention is to modify the age old Aldrop latch and have in its place a combination of the Aldrop latch and Night latch which will henceforth be called a 'COMBINATION LATCH' wherever appearing throughout this specification. In short this combination latch combines the virtues of both the Aldrop latch and Night latch. As such, here, even if the combination latch is engaged from outside the same can be disengaged by the occupants from inside the premises by Just operating a handle. Here the two handles (inside and outside) are linked by a common rod. Further object of this invention is to ensure double strength by having have two locking bolts (operating from either side of the door) moving simultaneously to interlock with the door frame. Further, when adapted to fit double doors the security offered by the combination latch is unparalleled as two locking bolts engage their corresponding receptacles thereby firmly sandwiching the two doors at the joint. Yet another object of this invention is to make the combination latch in such a nianncr that it offers absolutely no gap for jimmying or prying open. A further object of this invention is to have a locking system having a solid housing of its own which is integral with the body of the outer latch (a part of the combination latch). Yet another object of this invention is to conceal the locking bolt's movement by providing it with a housing of its own all along its length. This provision ensures that the culprits are unsure about the premises being occupied, A further object of tins invention is to strengthen the mortise and tenon joint where the door sections meet by fixing the combination latch at that point and thereby reinforcing the joint. While trying to force open doors opening inwards the mortise and tenon joint where the Mortise latch, Vertibolt, Night latch, Aldrop latch and Combination latch are fixed take the brunt of the attack. As such reinforcing this portion of the door will strengthen it further. According to an einbodimcnt of this invention the 'COMBINATION LATCH meant to be fitted to double doors comprises of an outer latch having a handle, locking boh and a locking systcni being fitted to one door. The other door is fitted with a corresponding receptacle. The inner door is fitted with the inner latch comprising of a handle, locking latch, locking bolt and a control latch to deadlock the locking bolt from inside. While the other inner door is also fitted with a corresponding receptacle. The two handles are linked by means of a common rod in such a manner that the handles operate in unison to engage the locking bolts to the receptacles and thereafter get deadlocked. According to another embodiment of this invention a 'COMBINATION LATCH' meant to be fitted to a single door comprises of a outer hitch having a handle, locking bolt and a locking system.. While the inner door is fitted with a inner latch com|)rising of a handle, locking bolt, locking latch and a control latch to dead lock the locking bolt when intended. On turning the handle either from inside or outside the locking bolt from the outer latch moves to engage with a hole in the door frame. While the locking bolt from the inner latch engages a corresponding receptacle. On activating the handle on the inner latch the locking bolt gets dead locked. Here again both the handles are linked by means of a single rod. For better understanding this invention will now be illustrated by way of example with reference to the accompanying drawings in which: Fig. 1 shows the front view of the double doors secured by means of the age old Aldrop latch. Fig. 1 (a), shows the plan view of the double doors secured by means of the Aldrop latch and tower bolt on the inside. Fig.2 shows the front view of a single door secured with a Aldrop latch. Fig. 2(a) shows the plan view of a single door fixed to the door frame by means of the Aldrop latch. Fig.3 shows the front view of the double doors fitted with a outer latch fixed to one door and a corresponding receptacle fixed to the other door. Fig. 3 (a) shows the plan view of the combination latch fixed to a double door and the locking bolt in the engaged position. Fig. 4 shows the front view of the combination latch fixed to a inwards opening single door. Here the locking bolt is shown engaged to the door frame (chaukat). I'ig. 4 (a) shows the plan view of tlic combination latch fixed to a single door with the two locking bolts in the engaged |)osition. fig.5 shows the movement of the locking bolt using the rack and pinion arrangement. Fig. 5 (a) shows the movement of the locking bolt using the cam driven nicchanism. figs. 1 & 1(a) shows the Aldrop latch 1 fixed to double doors 10 & 10a. Referring to fig, 1 (a) if a crowbar is inserted in the gap 18 and pulled, due to the leverage gained the bolts 5 holding the clamp 6 and tower bolt 2 give way thereby rendering this Aldrop latch arrangement useless. Further it can be seen that only a single locking bolt 3 that too operating only from one side of the door offers absolutely no resistance particularly in inward opening double doors. (See direction of arrow). Fig.2 & 2 (a) shows Aldrop latch 1 fixed to a single door 10. rig, 2 & 2 (a) shows the locking bolt 3 (of the Aldrop latch) engaged directly in a hole in door frame 9 on the outside. While the inner side of the door is secured by a Night latch 7 engaging a receptacle 16. Here the locking bolt 3 of the Night latch is deadlocked by the control latch 8. Where the single door opens inwards the gap 18 and the exposed portion of locking bolt 3 serves as a leverage point for the crowbar. Due to the extreme force used the bolts and screws holding the Aldrop latch 1 and receptacle 16 give way thereby releasing the door. Undoubtedly here the gap 18 which permits the insertion of a crowbar makes this system very vulnerable to burglary. Fig. 3 shows the combination latch used on double doors 10 & 10a. Here fig, 3 shows the front view of the outer latch with its locking bolt 3, engaging the receptacle 16 and being deadlocked by the locking system 20. While fig. 3a shows the plan view of the combination latch fixed to doors 10 & 10a. Here the locking bolt 3 of outer latch 2! engages with receptacle 16 ovi activating handle 11. . Simultaneously the locking bolt 3 of the inner latch 22 engages with its corresponding receptacle 16 and the locking bolt 3 can be deadlocked by pressing control latch 8. Here for added strength both the receptacles (inner and outer) arc fastened to each other by bolts passing through the door. F\g. 4 shows a front view of the combination latch fixed to a single door 10. Here on activating handle 11 of outer latch 21 the locking bolt 3 directly engages with a hole in the door frame 9. Fig. 4a shows the sectional plan view of the combination latch comprising of outer latch 2! and inner latch 22. The handles 11 are interconnected by means of a common rod. On activating the handle 11 the locking bolt 3 moves to engage the hole in the door frame 9 and the receptacle 16. While from outside the locking bolt 3 can be deadlocked by means of the locking system however, from inside the locking bolt 3 can be deadlocked by means of the control latch 8 or a locking system. VViihout deviating from the scope of this invention there are several ways of a'ctivating the'locking bolt 3 by operating the handle 11. However, only for the purposes of clarity fig. 5 shows a locking bolt 3 having a rack 15 on its one end while the pinion 14 has a handle 11 fixed to it. With their teeth engaged on moving the handle 11 either ways the locking bolt 3 reciprocates. Another method of reciprocating the locking bolt 3 is by using a cam driven mechanism as shown in fig. 6 where 22 is the cam fixed to handle 11. SALIENT FEATURES OF THE COMBINATION LATCH 1. In the case of a single door at the turn of the handle of the combination latch (either from inside or outside) two locking bolts move in unison to interlock with a hole in the door frame (from the outside) and receptacle (from the inside) simultaneously thereby providing double strength .and making the system burglar proof. From the inside by just pressing a button or turning a knob the inner locking bolt and locking latch can be deadlocked to serve as a Night latch or where a locking system is provided a key is turned to deadlock the same. 2. Whereas in the case of double doors the two locking bolts interlock with their corresponding receptacles thereby sandwiching the two halves of the doors and increasing the overall structural rigidity of the two halves of the door, 3. Both the handles are connected by a common rod as such the engagement and dis-cngagement of the locking bolts can be made both from inside as well i.s outside. Thereby making this system safe for: a. Children who are inadvertantly locked inside as the door can be opened from outside. b. Inmates of the premises who are deliberately locked from outside by burglans as in the case of existing Aldrop latches. 4. No gap for jimmying or prying open as the locking bolts have a housing of their own. 5. No dangling padlocks. Here the locking system is enclosed in a solid housing of its own to dead lock the locking bolt/s. 6. The mortise a'nd tenon junction over which the outer and inner latches are fixed further reinforces the joint. Merc the base plates of both the outer and inner latches sandwich the door with bolts (passing through the door) gripping the said base plates. 7. With the locking bolt now fully concealed potential burglars will be unsure about the premises being un-occupied. While 1 have described and illustrated the aforementioned embodiments of my present invention of a combination latch, 1 do not wish to limit myself to the exact from shown, described and illustrated, which is intended to illustrate the invention to show how best the same can be performed rather than to limit the scope of this invention. It is also to be expressly understood that this invention is susceptible to such changes and modifications which shall defmc no material departure from the salient features of this invention herein described and illustrated. 1.,a combination latch comprising of an inner and outer latch fixed to both the faces of the door in such a manner that their handles are linked by a common rod , on operating which the locking bolt of the outer latch engages the door frame directly and the locking bolt of the inner latch engages its receptacle [fixed to the said door frame] simultaneously; 2, a combination latch as claimed in claiml where, in the case of a door mill two wings, the two locking bolts move out to engage and deadlock mth their corresponding receptacles fixed to the other wing of the door ; 3, a combination latch as claimed in claim 1 and 2 where the locking bolt of the outer latch moves in a housing in such a manner that its movement is invisible; i.a combination latch as claimed in claims 1,2 and 3 where the outer latch has an integrated locking system to deadlock the locking bolts; 5. a combination latch as caimed in any of the preceding daims and is substantially hereinbefore described and illustrated.

Documents:

422-CHE-2004 CORRESPONDENCE OTHERS 11-03-2013.pdf

422-CHE-2004 FORM-13 11-03-2013.pdf

422-CHE-2004 AMENDED PAGES OF SPECIFICATION 15-05-2014.pdf

422-CHE-2004 AMENDED CLAIMS 04-12-2013.pdf

422-CHE-2004 AMENDED CLAIMS 15-05-2014.pdf

422-CHE-2004 AMENDED PAGES OF SPECIFICATION 04-12-2013.pdf

422-CHE-2004 EXAMINATION REPORT REPLY RECEIVED 04-12-2013.pdf

422-CHE-2004 EXAMINATION REPORT REPLY RECEIVED 15-05-2014.pdf

422-CHE-2004 FORM-13 05-05-2008.pdf

422-che-2004-abstract.pdf

422-che-2004-claims.pdf

422-che-2004-correspondnece-others.pdf

422-che-2004-description(complete).pdf

422-che-2004-description(provisional).pdf

422-che-2004-drawings.pdf

422-che-2004-form 1.pdf

422-che-2004-form 5.pdf