Title of Invention

A NIGHT LATCH

Abstract

A night latch consisting of a rectangular body (1) provided with a latch bolt knob (2) rotatably mounted on the front surface of the body to operate a latch bolt (4) guided in a solt provided in the flange (5) right angled to the body; said body is also provided with a safety catch knob (3) adjacent to latch bolt knob operable by a locking mechanism provided inside the body which are mounted on the base plate (10) which further consists of latch bolt plate (9) the forward end of which is riveted to latch bolt (4) and at the rear is guided on the knob spindle held by biaisng means (12,13); safety catch knob (3) a lever which arrest the movement of the latch bolt lever by quarter of it's turn; auto dead lock lever to arrest the backward movement of the bolt when operated by key or knob, but become free when pressed from the bolt side thereby arresting the further movement of bolt once it come out.

Full Text

ORIGINAL 843-MUM-2000 FORM 2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SPECIFICATION (See Section 10, rule 13) A NIGHT LATCH GODREJ & BOYCE MFG. CO. LTD. of LOCKS DIVISION PLANT-18, PIROJSHANAGAR, VIKHROLI, MUMBAI - 400 079 MAHARASHTRA, India INDIAN Company The following specification particularly describes the nature of the invention and the manner in which it is to be performed : - 29-03-2004 GRANTED The invention relates to a night latch. More particularly the invention relates to a night latch with plurality of levers. The conventional system of night latch are not made of sturdy material and not aesthetically good looking and requires frequent replacement of parts. They are not adequately full proof and are prone to failure due to the simple locking mechanism. Therefore, they are easily opened out from outside. Therefore, there is need to develop a night latch to obviate the aforesaid draw backs. The inventor with research has come out with a very unique locking mechanism with specific alteration of components which makes the lock strong enough and adequate privacy which is full proof to be opened by force or misused by unauthorized persons. The primary object of this invention is to provide a night latch with auto dead locking mechanism. The another object of this invention to provide a night latch having latch bolt with safety catch knob. Still further object of this invention is to provide a night latch which is strong and made from steel components. Another object of this invention is to provide a night latch bolt where the bolt is made of mazak / alloy with brass levers and brass plated nickel keys. Accordingly there is provided a night latch consisting a rectangular body (1) provided with a latch bolt knob (2) rotatably mounted on the front surface of the body to operate a latch bolt (4) guided in a slot provided in the flange (5) right angled to the body; said body is also provided with a safety catch knob (3) adjacent to latch bolt knob operable by a locking mechanism provided inside the body which are mounted on the base plate (10) which further consists of latch bolt plate (9)the forward end of which is riveted to latch bolt (4) and at the rear is guided on the knob spindle held by biasing means (12,13); safety catch knob (3) with a lever which arrest the movement of the latch bolt by quarter of it's turn; auto dead locking mechanism comprising two lances (17, 18)/projections on latch bolt plate which remains pressed with dead lock lever to arrest the backward movement of the bolt when operated by key or knob, but become free when pressed from the bolt side thereby arresting the further movement of the bolt once it come out. The body may be of any construction, round, oval, rectangle, square. The bolt is made up of steel. The body is powder coated. The invention now will be clear from the following description with reference to Figures from 1 to 11 in the accompanying specification. Fig 1. Front view of night latch body. Fig 2. Isometric front view of night latch body. Fig 3. Side view of night latch. Fig 4. Backside view of night latch. Fig 5. Isometric back side view of night latch. Fig 6.: is a Schematic view of a night latch locking mechanism. Fig 7. : is a Schematic back view of a night latch Fig 8.: is a Exploded view of a night latch. Fig 9.: is a Front view of receptacle with a night latch FiglO.: is a Hold back position of a night latch. Fig 11.: is a Side view position of a night latch. Referring to figures 1 to 11 a rectangular body (1) made of steel metal having fastening provisions at it's four corners to fix it on the door. The body on it's front face provided with latch bolt knob and safety catch knob (2 & 3) rotably mounted to operate the latch bolt or to dead lock by means of safety catch in it's extended as well as retracted position. The body is provided with a flange (5) which is at right angle to the front surface of the body having recess to guide the bolt and the provision to fix it on the door. The locking mechanism is fixed on the backside of the body on a base plate (10) with latch bolt plate (9) and dead lock lever (11) provided with dead lock lever spring (12) and latch bolt spring (13) with latch bolt lance (17, 18) knob spindle connector receiver (14). The whole assembly is covered by a back plate (8). Description : The invention relates to a locking system as described below. The locking system has got a latch bolt with auto deadlocking mechanism. This lock is also provided with safety catch button for deadlocking which makes lock inoperative from outside even with it's own key. This can be used as privacy feature also. The innovation of this lock lies in latch bolt mechanism which is unique. The crank type mechanism is used with to simple torsion springs. In normal lock mechanisms simple tension springs are used which are more prone to failure. The whole mechanism is made of sheet metal steel components which is strong and durable. In normal locks the mechanism is made of mazak parts which has got tendency to wear out faster and often fail in case of unusual loads/ forces during abuse or misuse. Once the components are failed, the lock looses the full control as mazak components breaks. In case of sheet metal components lock does not loose full control rather it will bend and remain functional with little bit difficulties. Construction: The locking mechanism is made of sheet metal components with brass levers and brass nickel plated keys. The body is made of steel and power coated for better life. The internal components are made of steel and are zinc plated. The base plate is inserted into the body from open side and safety catch knob from top side and riveted with safety catch. Then the knob is inserted from top side of body and latch bolt is inserted on knob and body window simultaneously. Then dead lock lever is inserted on knob spindle and retained by a circlip. Two springs are assembled and back cover is fitted with the help of screw. Operation: The lock is operated by knob from inside and key from outside. The latch bolt gets deadlocked on its own when the door is shut. This feature is essential to avoid opening of the lock by unknown person with the help of screw driver or similar object. The safety catch from inside provides additional security and privacy. This is an embodiment of an invention, Several modifications are possible which many be considered within the ambit and spirit of this invention. Since many modifications, variations and changes in detail may be made to the above described embodiments, it is intended that all matters described in the foregoing description as described in the accompanying specification. WE CLAIM: 1. A night latch consisting a rectangular body (1) provided with a latch bolt knob (2) rotatably mounted on the front surface of the body to operate a latch bolt (4) guided in a slot provided in the flange (5) right angled to the body; said body is also provided with a safety catch knob (3) adjacent to latch bolt knob operable by a locking mechanism provided inside the body which are mounted on the base plate (10) which further consists of latch bolt plate (9)the forward end of which is riveted to latch bolt (4) and at the rear is guided on the knob spindle held by biasing means (12,13); safety catch knob (3) with a lever which arrest the movement of the latch bolt by quarter of it's turn; auto dead .locking mechanism comprising two lances (17, 18)/projections on latch bolt plate which remains pressed with dead lock lever to arrest the backward movement of the bolt when operated by key or knob, but become free when pressed from the bolt side thereby arresting the further movement of the bolt once it come out. 2. A night latch as claimed in claim 1 wherein, the body may be of any construction, round, oval, rectangle, suare. 3. A night latch as claimed in claim 1 wherein, the bolt is made up of steel. 4. A night latch as claimed in claim 1 wherein, the body is powder coated. 5. A night latch as claimed in claim 1 and substantially herein described and illustrated in fig 1 to 11 in the accompanying specification. Dated this 14th day of September, 2000. HIRAL CHANDRAKANT JOSHI AGENT FOR GODREJ & BOYCE MFG. CO. LTD.

Documents:

843-mum-2000-cancelled pages(29-03-2004).pdf

843-mum-2000-claims(granted)-(29-03-2004).doc

843-mum-2000-claims(granted)-(29-03-2004).pdf

843-mum-2000-correspondence(29-03-2004).pdf

843-mum-2000-correspondence(ipo)-(08-12-2005).pdf

843-mum-2000-drawing(29-03-2004).pdf

843-mum-2000-form 1(14-09-2000).pdf

843-mum-2000-form 19(23-12-2003).pdf

843-mum-2000-form 2(granted)-(29-03-2004).doc

843-mum-2000-form 2(granted)-(29-03-2004).pdf

843-mum-2000-form 3(29-03-2004).pdf

843-mum-2000-form 5(29-03-2004).pdf

843-mum-2000-power of attorney(14-09-2000).pdf

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