Indian Patents. 263640:A LOCK ASSEMBLY

Title of Invention	A LOCK ASSEMBLY
Abstract	A fastener free housing for a lock is disclosed. Also disclosed are guide means for slider dead blot and a play-free engagement of the lock assembly mechanism for smooth functioning of the lock.

Full Text	FORM-2 THE PATENT ACT, 1970 (39 of 1970) & THE PATENT RULES, 2003 PROVISIONAL SPECIFICATION (See section 10 and Rule 13) "LOCK OPERABLE WITH DEDICATED KEY " DR. JOSHI PRABHAKR ANANT An Indian National of J-61, MIDC, Bhosari, Pune-411 026, Maharashtra, India. And JOSHI SALIL PRABHAKAR An Indian National of J-61, MIDC, Bhosari, Pune-411 026, Maharashtra, India THE FOLLOWING SPECIFICATION DESCRIBES THE INVENTION FIELD OF INVENTION: This invention relates to a Lock operable with a dedicated key. In particular, this invention relates to a cylinder lock operable with a dedicated key. INTRODUCTION: Locks have been used to prevent unauthorised access and to protect valuables stored in drawers and cabinets. Various types of locks available are: lever locks, pad locks, cable locks, mortise locks, combination locks, cylinder lock and the like. A cylinder lock is a lock in which a cylinder must rotate to open the lock. The cylinder is prevented from rotating by a variety of locking devices like a pin, disc or wafer. The key has serrations on one edge of the flat face to lift and align the contact surfaces of the locking devices to that of the housing and cylinder. Thus with the key in place the cylinder is free to rotate with reference to the housing. This relative movement is used to disengage a bolt from its housing and allow opening of the drawers or cupboards. Conventional cylinder pin locks were manufactured with sets of pins of varying lengths assembled inline on a stationary housing to arrest the movement of the cylinder. Modern day pin-tumbler locks have holes in more than one axis and use many sets of locking pins. These multi axis pins necessitate use of dimpled keys as multi axis serration is not possible on a flat key. Dimples on the key face serve the same function as serrations and permit 2 positioning of the pins in the housing to align their contact faces. Dimpled keys also permit reversible key entry. Dimpled keys are difficult to duplicate and therefore affords an enhanced security. Multi axis pins increase the number of combinations possible in a lock thereby reducing the length of the cylinder required to accommodate the lock pins affording higher security and very reasonable costs. PRIOR ART: Some of the locks used for drawers and cupboards are described herein under: US Patent 5678438 discloses a cabinet lock which is convert-able to a door lock by using an extending sleeve and mounting plates. This is a single axis cylinder pin lock, with limited number of possible key combination and therefore not highly secure. US Patent 5657652 discloses a lock for cabinet doors and drawers employing a unitary shell with an adjacent main bolt and self latching dead locking bolt. A pivoted locking arm prevents external retraction of the main bolt without the use of a key. This invention is an adaptation of self latching door lock to a drawer or cabinet lock, by providing a spring loaded self latching dead bolt along with a key operated dead bolt. This provision does not enhance the level protection of this lock. US Patent 5551263 discloses a diamond back lock configuration as used in drawer locks, includes a dead bolt with an angled slot. A projecting cam member on the lock plug engages the angled slot and extends the dead bolt on turning the key, achieving fully extended position when the lock plug is rotated 90° as compared to conventional non-angled slot with 180° of rotation. 3 This is a single axis cylinder pin lock, with limited number of possible key combination and therefore not highly secure. US Patent 5121619 discloses a speed release mechanism for cylinder and plug assembly for use with cabinet locks. This invention relates replaceable lock cylinder and a spring loaded ejection mechanism for quick removal of the same. Replacement of the lock unit and key without having to remove the other parts like lock housing and dead bolt is useful when the keys are lost. However to reach the release button which is embedded in the frame work of the cabinet, the cabinet has to be opened first with a master key and retaining screws of the housing removed before releasing the lock cylinder. US Patent 4920774 discloses self aligning re-key able pin tumbler cabinet door lock. In this invention the cylinder and plug assembly is removable by releasing a set screw. This provision does not enhance the level of security of the lock. OBJECTS OF THE INVENTION One of the objects of this invention is to provide a drawer and cabinet lock which is compact in size and sleek in shape with fewer protruding parts. Another object of this invention is to provide a drawer and cabinet lock which is easy to manufacture and assemble. Yet another object of this invention is to provide a drawer and cabinet lock which is ergonomically better suited for the end user. 4 Yet another object of this invention is to provide a drawer and cabinet lock which is difficult to tamper, and break open. Yet another object of this invention is to provide a drawer and cabinet lock which is smooth to operate and provides uniform and continuous movement of the dead bolt. Yet another object of this invention is to provide a drawer and cabinet lock which has low frictional resistance and is capable of providing several thousand operation of forward and reverse movement of the dead bolt while maintaining accuracy of stroke and alignment. Yet another object of this invention is to provide a drawer and cabinet lock wherein the components are mass produced and are interchangeable. Yet another object of this invention is to provide a drawer and cabinet lock that is robust. Yet another object of this invention is to provide a drawer and cabinet lock that does not require lubrication. Yet another object of this invention is to provide a drawer and cabinet lock that provides precise locking and unlocking. SUMMARY OF THE INVENTION The invention relates to an improved drawer and cabinet lock and lock mechanism. Use of multi axis cylinder lock pins enables more than a billion combinations and makes it possible to manufacture highly secure and economical locking system. It also reduces the overall dimensions of the lock making it suitable for assembly in cabinets and drawers. 5 By varying the lengths of pin- tumbler and key, the drawer lock can be used for a wide range of thickness of drawer/cabinet panel. As the lock assembly is interchangeably mountable in both horizontal and vertical configurations it reduces inventory of components in manufacturing. The lock in accordance with one aspect of this invention includes of a lock case formed typically out of steel sheets. The central portion of the lock case has a recess defined by arcuate side walls and operative front and back walls. The arcuate side walls of the central recess bent out wards to define two flat faces on either side. The edges of the flat face are bent upwards and along with the front and back walls form a continuous peripheral rim enclosing the central recess and the flat faces. The operative front wall of the lock case has an opening formed by cutting out a typically rectangular shape, to allow ingress and egress of a dead locking bolt. The shape and size of the said opening complements the dead bolt of the lock. The shorter side of the rectangular opening has two integral lugs formed by bending remnant portion of the material inwards, substantially at right angles to form two locking lugs. The operative back wall of the lock case has another typically rectangular aperture formed by punching. The flat face on either side of the central recess has punched circular holes adapted to receive fasteners. The lock in accordance with another aspect of this invention includes a cover plate having various formations. The operative front edge of the cover plate has an extension bent substantially at right angles to the flat surface of the cover plate. This bent extension defines another typically rectangular opening, marginally larger than the opening provided on the lock casing. The edge formed by the longer side of the rectangular opening, distal to the surface of 6 the cover plate is bent inwards. The outer profile of the cover plate is complementary to the profile enclosed by the peripheral rim of the lock case. The cover plate has a substantially circular central opening adapted to receive a complementary cylinder lock unit. The central opening is provided with semicircular notches adapted to receive fasteners. Two integral lugs are formed by slitting and bending part of the cover plate material to form a guide channel between the lugs. Another integral lug formed by similar method, is located towards the bent extension of the front edge. The operative back edge of the cover plate has a flat lug formed by notching. The lock in accordance with another aspect of this invention includes a slider-dead bolt unit consisting of an operative front end made typically of hardened steel rigidly press fitted to a profiled slider unit. The front end of the slider-dead bolt unit has a rectangular cross section marginally smaller than the rectangular opening provided on the operative front wall of the lock casing. The profiled slider plate has three of edges bent at right angles to the surface of the slider plate. The central area of the profiled plate has a cut opening. The remnant portion of the opening defining two cog profiles, adapted to engage with a complementary profiled driving lug. The lock in accordance with another aspect of this invention includes a compact cylinder lock unit. The cylinder lock unit is fitted to the circular central opening provided on the cover plate by fasteners. The cylinder lock unit includes a rotary central cylindrical core fitted within the stationary outer cylinder housing. The inner core, adapted to receive a key shank of rectangular cross section, is prevented from rotating with reference to the 7 cylinder housing by pressure pins and lock pins fitted in radial drilled holes in both the cylinder and housing. When a corresponding key is inserted the key slot the profiles provided on the key align the locking pins inside the cylinder housing to allow rotation of the cylinder with reference to the cylinder housing. The operative rear end of the inner core has two profiled driving lugs adapted to engage the cogs profiled on the slider-dead bolt unit. The lock in accordance with another aspect of this invention includes a resilient polymer lever securely mounted within the lock assembly that absorbs the lateral play of the slider-dead bolt to reduce noise generated and improves the smoothness of forward and reverse movement of the slider unit assembly. The lock in an operative configuration is fitted on the panel of either a drawer unit or one of the shutters of a cabinet in a manner that when the slider-dead bolt in a fully retracted position, the drawer or the cabinet is open-able. To lock the unit the key is turned and the slider-dead bolt extends outward from the lock case to engage the dead bolt housing fitted on the fixed portion to prevent the movement of the drawer unit with reference to desk or arrest relative movement of the shutter When a key is inserted in the key slot, the profiles provided on the key align the locking pins inside the cylinder housing to allow rotation of the cylinder with reference to the cylinder housing. The driving lugs provided on the end of the cylinder engages the cogs of the profiled plates and move the slider-dead bolt similar to the movement of a rotary pinion and a sliding rack. 8 The design and positioning of the driving lugs ensures that the movement of the slider-dead bolt is smooth, uniform and precisely controlled. The position of the driving lugs with reference to the cogs profiled with in a slot limits and restricts the movement of the slider dead bolt. In the as inserted position of the key, in the key slot, the driving lugs provided on the lock cylinder is in engagement with the cogs on the profiled plate. In this position the outer surface of the driving lug is abutting one of the side walls of the slot and prevents back ward movement of the slider-dead bolt. In this position the key can not be turned in an anticlockwise direction. As the key is turned in a clockwise direction the slider-dead bolts moves forward and at 360° of key rotation the outer surface of the driving lug abuts the other side wall of the slot, thereby preventing further clockwise rotation of the key. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS All the aspects and advantages of the invention will become apparent with the description of the preferred, non-limiting embodiment, when read together with the accompanying drawings, in which: Figure 1: is an isometric view of the drawer lock in accordance with this invention; Figure 2: is an obverse exploded perspective view of a lock case and cover plate for the drawer lock of figure 1; Figure 3: is a reverse exploded perspective view of the lock case and cover plate for the drawer lock of figure 1; Figure 4: is the rear view of the drawer lock of figure 1; Figure 5: is the plan view of the drawer lock of figure 1; Figure 6: is the front view of the drawer lock of figure 1; 9 Figure 7: is the sectional view of the drawer lock of figure 1; Figure 8: is a sectional view of the lock assembly of the drawer lock of figure 1 showing the details of the engagement of the slider dead bolt assembly with the driving lugs ; Figure 9: is a plan view of slider-dead bolt assembly of the drawer lock of figure 1; Figure l0 is a sectional elevation of the slider-dead bolt assembly of the drawer lock of figure 1; Figure 11: is a sectional end view of slider-dead bolt assembly of the drawer lock of figure 1; Figure 12: shows details of the engagement of the slider-dead blot assembly with the driving lug at 0° of key rotation for the lock of Figure 1; Figure 13: shows details as in Figure 12 at 90° of key rotation; Figure 14: shows details as in Figure 12 at 180° of key rotation; Figure 15: shows details as in Figure 12 at 270° of key rotation; Figure 16: shows details as in Figure 12 at 360 of key rotation. DETAILED DESCRIPTION OF THE DRAWINGS: Referring to the accompanying drawings, the drawer and cabinet lock according to this invention is indicated generally by the reference numeral 10. Referring to Figure 1, the lock consists of a lock case 2, cover plate 4, slider-dead bolt 6, cylinder lock unit 14, and a corresponding key 12. 10 Referring to Figure 2, the lock case 2 has a central recess 100 defined by arcuate side walls 110 and 120 and operative front and back walls 130 and 140 respectively. The arcuate side walls of the central recess bent out wards to define two flat faces 50 on either side. The edges of the flat face are bent upwards and along with the front and back walls form a continuous peripheral rim 150 enclosing the central recess and the flat faces. The operative front wall 130 of the lock case has an opening 5 formed by cutting out a typically rectangular shape, to allow ingress and egress of a dead locking bolt. The shape and size of the opening 5 complements the dead bolt of the lock. The shorter side of the rectangular opening has two integral lugs 44 formed by bending remnant portion of the material inwards, substantially at right angles to form two locking lugs.The operative back wall of the lock case has another typically rectangular aperture 46 formed by punching. The flat face on either side of the central recess has punched circular holes 8 adapted to receive fasteners. Referring to Figures 2 and 3 the cover plate 4 is provided with various formations. The operative front edge 160 of the cover plate has an extension bent substantially at right angles to the flat surface of the cover plate. This bent extension defines another typically rectangular opening 7, marginally larger than the opening provided on the lock casing 2. The edge 15 formed by the longer side of the rectangular opening, distal to the surface of the cover plate is bent inwards. The outer profile of the cover plate is complementary to the profile enclosed by the peripheral rim 150 of the lock case. The cover plate has a substantially circular central opening 9 adapted to receive a complementary cylinder lock unit 14. The central opening is provided with semicircular notches 170 adapted to receive fasteners. Two 11 integral lugs 26 are formed by slitting and bending part of the cover plate material to form a guide channel between the lugs. Another integral lug 38 formed by similar method, is located towards the bent extension of the front edge 160. The operative back edge 170 of the cover plate has a flat lug 40 formed by notching. Referring to Figures 9, 10 and 11a slider-dead bolt unit consisting of an operative front end 6 made typically of hardened steel rigidly press fitted to a profiled slider unit 32. The front end of the slider-dead bolt unit has a rectangular cross section marginally smaller than the rectangular opening 5 provided on the operative front wall 130 of the lock casing 2. The profiled slider plate has three of edges 33, 35 and 37 bent at right angles to the surface of the slider plate. The central area of the profiled plate 32 has a cut opening 29. The remnant portion of the opening defining two cog profiles 28, adapted to engage with a complementary profiled driving lug. Referring to Figure 7 the compact cylinder lock unit 14 is fitted to the circular central opening 9 provided on the cover plate by fasteners (not specifically shown). The cylinder lock unit includes a rotary central cylindrical core 18 fitted within the stationary outer cylinder housing 16. The inner core, adapted to receive a key shank of rectangular cross section, is prevented from rotating with reference to the cylinder housing by pressure pins 22 and lock pins 20 fitted in radial drilled holes in both the cylinder and housing. When a corresponding key 12 is inserted the key slot the profiles provided on the key align the locking pins inside the cylinder housing to allow rotation of the cylinder with reference to the cylinder housing. The operative rear end of the 12 inner core has two profiled driving lugs 24 adapted to engage the cogs 28 profiled on the slider-dead bolt unit. Referring to Figure 8, a resilient polymer lever 30 is securely mounted on lug 38 within the lock assembly to absorb the lateral play of the slider-dead bolt, to reduce noise generated and improve the smoothness of forward and reverse movement of the slider unit assembly. By providing the lugs 44, flat seats 50, edge strip 15, slot 46, and lug 40 the lock casing 2 and the cover plate 4 are assembled to each other with out any fastener like nut bolts, screws or rivets. Referring to Figure 4, the outer surface 11 of the lock casing and visible portion of the slider-bolt assembly are aesthetically finished. Referring to Figure 5, the compact profile of a fully assembled lock in plan view is shown. Referring to Figure 6, the compact profile of a fully assembled lock in front elevation view is shown. Figure 12 shows one of the relative positions of the slider-bolt assembly with reference to the rotation of the key in the key slot. In this position the key is in its as inserted position defined as 0° of rotation. The slider-dead bolt is in its fully retracted position. Figure 13 shows another relative position of the slider-bolt assembly with reference to the rotation of the key in the key slot. In this position the key has 13 been turned and is at 90o of key rotation. The slider-dead bolt is in a partly protruding position after completing approximately one fourth of its forward movement. Figure 14 shows another relative position of the slider-bolt assembly with reference to the rotation of the key in the key slot. In this position the key has been turned and is at 180 of key rotation. The slider-dead bolt is in a partly protruding position after completing approximately half of its forward movement. Figure 15 shows another relative position of the slider-bolt assembly with reference to the rotation of the key in the key slot. In this position the key has been turned and is at 270° of key rotation. The slider-dead bolt is in a partly protruding position after completing approximately three fourth of its forward movement. Figure 16 shows another relative position of the slider-bolt assembly with reference to the rotation of the key in the key slot. In this position the key has been turned and is at 360° of key rotation. The slider-dead bolt is in a fully protruded position after completing its forward movement. While considerable emphasis has been placed herein on the particular features of a drawer and cabinet lock the improvisation with regards to it, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiment without departing from the principles of the invention. These and other modifications in the nature of the invention or the preferred embodiments will be apparent to those skilled in the 14 art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. 15

Full Text

FORM-2
THE PATENT ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003
PROVISIONAL SPECIFICATION
(See section 10 and Rule 13)
"LOCK OPERABLE WITH DEDICATED KEY "
DR. JOSHI PRABHAKR ANANT
An Indian National
of J-61, MIDC, Bhosari, Pune-411 026, Maharashtra, India.
And
JOSHI SALIL PRABHAKAR
An Indian National
of J-61, MIDC, Bhosari, Pune-411 026, Maharashtra, India
THE FOLLOWING SPECIFICATION DESCRIBES THE INVENTION

FIELD OF INVENTION:
This invention relates to a Lock operable with a dedicated key. In particular, this invention relates to a cylinder lock operable with a dedicated key.
INTRODUCTION:
Locks have been used to prevent unauthorised access and to protect valuables stored in drawers and cabinets.
Various types of locks available are: lever locks, pad locks, cable locks, mortise locks, combination locks, cylinder lock and the like.
A cylinder lock is a lock in which a cylinder must rotate to open the lock. The cylinder is prevented from rotating by a variety of locking devices like a pin, disc or wafer. The key has serrations on one edge of the flat face to lift and align the contact surfaces of the locking devices to that of the housing and cylinder. Thus with the key in place the cylinder is free to rotate with reference to the housing. This relative movement is used to disengage a bolt from its housing and allow opening of the drawers or cupboards.
Conventional cylinder pin locks were manufactured with sets of pins of varying lengths assembled inline on a stationary housing to arrest the movement of the cylinder. Modern day pin-tumbler locks have holes in more than one axis and use many sets of locking pins. These multi axis pins necessitate use of dimpled keys as multi axis serration is not possible on a flat key. Dimples on the key face serve the same function as serrations and permit
2

positioning of the pins in the housing to align their contact faces. Dimpled keys also permit reversible key entry. Dimpled keys are difficult to duplicate and therefore affords an enhanced security. Multi axis pins increase the number of combinations possible in a lock thereby reducing the length of the cylinder required to accommodate the lock pins affording higher security and very reasonable costs.
PRIOR ART:
Some of the locks used for drawers and cupboards are described herein under: US Patent 5678438 discloses a cabinet lock which is convert-able to a door lock by using an extending sleeve and mounting plates. This is a single axis cylinder pin lock, with limited number of possible key combination and therefore not highly secure.
US Patent 5657652 discloses a lock for cabinet doors and drawers employing a unitary shell with an adjacent main bolt and self latching dead locking bolt. A pivoted locking arm prevents external retraction of the main bolt without the use of a key. This invention is an adaptation of self latching door lock to a drawer or cabinet lock, by providing a spring loaded self latching dead bolt along with a key operated dead bolt. This provision does not enhance the level protection of this lock.
US Patent 5551263 discloses a diamond back lock configuration as used in drawer locks, includes a dead bolt with an angled slot. A projecting cam member on the lock plug engages the angled slot and extends the dead bolt on turning the key, achieving fully extended position when the lock plug is rotated 90° as compared to conventional non-angled slot with 180° of rotation.
3

This is a single axis cylinder pin lock, with limited number of possible key combination and therefore not highly secure.
US Patent 5121619 discloses a speed release mechanism for cylinder and plug assembly for use with cabinet locks. This invention relates replaceable lock cylinder and a spring loaded ejection mechanism for quick removal of the same. Replacement of the lock unit and key without having to remove the other parts like lock housing and dead bolt is useful when the keys are lost. However to reach the release button which is embedded in the frame work of the cabinet, the cabinet has to be opened first with a master key and retaining screws of the housing removed before releasing the lock cylinder.
US Patent 4920774 discloses self aligning re-key able pin tumbler cabinet door lock. In this invention the cylinder and plug assembly is removable by releasing a set screw. This provision does not enhance the level of security of the lock.
OBJECTS OF THE INVENTION
One of the objects of this invention is to provide a drawer and cabinet lock which is compact in size and sleek in shape with fewer protruding parts. Another object of this invention is to provide a drawer and cabinet lock which is easy to manufacture and assemble.
Yet another object of this invention is to provide a drawer and cabinet lock which is ergonomically better suited for the end user.
4

Yet another object of this invention is to provide a drawer and cabinet lock
which is difficult to tamper, and break open.
Yet another object of this invention is to provide a drawer and cabinet lock
which is smooth to operate and provides uniform and continuous movement
of the dead bolt.
Yet another object of this invention is to provide a drawer and cabinet lock
which has low frictional resistance and is capable of providing several
thousand operation of forward and reverse movement of the dead bolt while
maintaining accuracy of stroke and alignment.
Yet another object of this invention is to provide a drawer and cabinet lock
wherein the components are mass produced and are interchangeable.
Yet another object of this invention is to provide a drawer and cabinet lock
that is robust.
Yet another object of this invention is to provide a drawer and cabinet lock
that does not require lubrication.
Yet another object of this invention is to provide a drawer and cabinet lock
that provides precise locking and unlocking.
SUMMARY OF THE INVENTION
The invention relates to an improved drawer and cabinet lock and lock mechanism. Use of multi axis cylinder lock pins enables more than a billion combinations and makes it possible to manufacture highly secure and economical locking system. It also reduces the overall dimensions of the lock making it suitable for assembly in cabinets and drawers.
5

By varying the lengths of pin- tumbler and key, the drawer lock can be used for a wide range of thickness of drawer/cabinet panel. As the lock assembly is interchangeably mountable in both horizontal and vertical configurations it reduces inventory of components in manufacturing.
The lock in accordance with one aspect of this invention includes of a lock case formed typically out of steel sheets. The central portion of the lock case has a recess defined by arcuate side walls and operative front and back walls. The arcuate side walls of the central recess bent out wards to define two flat faces on either side. The edges of the flat face are bent upwards and along with the front and back walls form a continuous peripheral rim enclosing the central recess and the flat faces. The operative front wall of the lock case has an opening formed by cutting out a typically rectangular shape, to allow ingress and egress of a dead locking bolt. The shape and size of the said opening complements the dead bolt of the lock. The shorter side of the rectangular opening has two integral lugs formed by bending remnant portion of the material inwards, substantially at right angles to form two locking lugs. The operative back wall of the lock case has another typically rectangular aperture formed by punching. The flat face on either side of the central recess has punched circular holes adapted to receive fasteners.
The lock in accordance with another aspect of this invention includes a cover plate having various formations. The operative front edge of the cover plate has an extension bent substantially at right angles to the flat surface of the cover plate. This bent extension defines another typically rectangular opening, marginally larger than the opening provided on the lock casing. The edge formed by the longer side of the rectangular opening, distal to the surface of
6

the cover plate is bent inwards. The outer profile of the cover plate is complementary to the profile enclosed by the peripheral rim of the lock case. The cover plate has a substantially circular central opening adapted to receive a complementary cylinder lock unit. The central opening is provided with semicircular notches adapted to receive fasteners. Two integral lugs are formed by slitting and bending part of the cover plate material to form a guide channel between the lugs. Another integral lug formed by similar method, is located towards the bent extension of the front edge. The operative back edge of the cover plate has a flat lug formed by notching.
The lock in accordance with another aspect of this invention includes a slider-dead bolt unit consisting of an operative front end made typically of hardened steel rigidly press fitted to a profiled slider unit. The front end of the slider-dead bolt unit has a rectangular cross section marginally smaller than the rectangular opening provided on the operative front wall of the lock casing.
The profiled slider plate has three of edges bent at right angles to the surface of the slider plate. The central area of the profiled plate has a cut opening. The remnant portion of the opening defining two cog profiles, adapted to engage with a complementary profiled driving lug.
The lock in accordance with another aspect of this invention includes a compact cylinder lock unit. The cylinder lock unit is fitted to the circular central opening provided on the cover plate by fasteners. The cylinder lock unit includes a rotary central cylindrical core fitted within the stationary outer cylinder housing. The inner core, adapted to receive a key shank of rectangular cross section, is prevented from rotating with reference to the
7

cylinder housing by pressure pins and lock pins fitted in radial drilled holes in both the cylinder and housing. When a corresponding key is inserted the key slot the profiles provided on the key align the locking pins inside the cylinder housing to allow rotation of the cylinder with reference to the cylinder housing. The operative rear end of the inner core has two profiled driving lugs adapted to engage the cogs profiled on the slider-dead bolt unit.
The lock in accordance with another aspect of this invention includes a resilient polymer lever securely mounted within the lock assembly that absorbs the lateral play of the slider-dead bolt to reduce noise generated and improves the smoothness of forward and reverse movement of the slider unit assembly.
The lock in an operative configuration is fitted on the panel of either a drawer unit or one of the shutters of a cabinet in a manner that when the slider-dead bolt in a fully retracted position, the drawer or the cabinet is open-able. To lock the unit the key is turned and the slider-dead bolt extends outward from the lock case to engage the dead bolt housing fitted on the fixed portion to prevent the movement of the drawer unit with reference to desk or arrest relative movement of the shutter
When a key is inserted in the key slot, the profiles provided on the key align the locking pins inside the cylinder housing to allow rotation of the cylinder with reference to the cylinder housing. The driving lugs provided on the end of the cylinder engages the cogs of the profiled plates and move the slider-dead bolt similar to the movement of a rotary pinion and a sliding rack.
8

The design and positioning of the driving lugs ensures that the movement of the slider-dead bolt is smooth, uniform and precisely controlled. The position of the driving lugs with reference to the cogs profiled with in a slot limits and restricts the movement of the slider dead bolt. In the as inserted position of the key, in the key slot, the driving lugs provided on the lock cylinder is in engagement with the cogs on the profiled plate. In this position the outer surface of the driving lug is abutting one of the side walls of the slot and prevents back ward movement of the slider-dead bolt. In this position the key can not be turned in an anticlockwise direction. As the key is turned in a clockwise direction the slider-dead bolts moves forward and at 360° of key rotation the outer surface of the driving lug abuts the other side wall of the slot, thereby preventing further clockwise rotation of the key.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
All the aspects and advantages of the invention will become apparent with the
description of the preferred, non-limiting embodiment, when read together
with the accompanying drawings, in which:
Figure 1: is an isometric view of the drawer lock in accordance with this
invention;
Figure 2: is an obverse exploded perspective view of a lock case and cover
plate for the drawer lock of figure 1;
Figure 3: is a reverse exploded perspective view of the lock case and cover
plate for the drawer lock of figure 1;
Figure 4: is the rear view of the drawer lock of figure 1;
Figure 5: is the plan view of the drawer lock of figure 1;
Figure 6: is the front view of the drawer lock of figure 1;
9

Figure 7: is the sectional view of the drawer lock of figure 1;
Figure 8: is a sectional view of the lock assembly of the drawer lock of
figure 1 showing the details of the engagement of the slider dead bolt assembly with the driving lugs ;
Figure 9: is a plan view of slider-dead bolt assembly of the drawer lock of
figure 1;
Figure l0 is a sectional elevation of the slider-dead bolt assembly of the drawer lock of figure 1;
Figure 11: is a sectional end view of slider-dead bolt assembly of the drawer lock of figure 1;
Figure 12: shows details of the engagement of the slider-dead blot assembly with the driving lug at 0° of key rotation for the lock of Figure 1;
Figure 13: shows details as in Figure 12 at 90° of key rotation;
Figure 14: shows details as in Figure 12 at 180° of key rotation;
Figure 15: shows details as in Figure 12 at 270° of key rotation;
Figure 16: shows details as in Figure 12 at 360 of key rotation.
DETAILED DESCRIPTION OF THE DRAWINGS:
Referring to the accompanying drawings, the drawer and cabinet lock according to this invention is indicated generally by the reference numeral 10. Referring to Figure 1, the lock consists of a lock case 2, cover plate 4, slider-dead bolt 6, cylinder lock unit 14, and a corresponding key 12.
10

Referring to Figure 2, the lock case 2 has a central recess 100 defined by arcuate side walls 110 and 120 and operative front and back walls 130 and 140 respectively. The arcuate side walls of the central recess bent out wards to define two flat faces 50 on either side. The edges of the flat face are bent upwards and along with the front and back walls form a continuous peripheral rim 150 enclosing the central recess and the flat faces. The operative front wall 130 of the lock case has an opening 5 formed by cutting out a typically rectangular shape, to allow ingress and egress of a dead locking bolt. The shape and size of the opening 5 complements the dead bolt of the lock. The shorter side of the rectangular opening has two integral lugs 44 formed by bending remnant portion of the material inwards, substantially at right angles to form two locking lugs.The operative back wall of the lock case has another typically rectangular aperture 46 formed by punching. The flat face on either side of the central recess has punched circular holes 8 adapted to receive fasteners.
Referring to Figures 2 and 3 the cover plate 4 is provided with various formations. The operative front edge 160 of the cover plate has an extension bent substantially at right angles to the flat surface of the cover plate. This bent extension defines another typically rectangular opening 7, marginally larger than the opening provided on the lock casing 2. The edge 15 formed by the longer side of the rectangular opening, distal to the surface of the cover plate is bent inwards. The outer profile of the cover plate is complementary to the profile enclosed by the peripheral rim 150 of the lock case. The cover plate has a substantially circular central opening 9 adapted to receive a complementary cylinder lock unit 14. The central opening is provided with semicircular notches 170 adapted to receive fasteners. Two
11

integral lugs 26 are formed by slitting and bending part of the cover plate material to form a guide channel between the lugs. Another integral lug 38 formed by similar method, is located towards the bent extension of the front edge 160. The operative back edge 170 of the cover plate has a flat lug 40 formed by notching.
Referring to Figures 9, 10 and 11a slider-dead bolt unit consisting of an operative front end 6 made typically of hardened steel rigidly press fitted to a profiled slider unit 32. The front end of the slider-dead bolt unit has a rectangular cross section marginally smaller than the rectangular opening 5 provided on the operative front wall 130 of the lock casing 2.
The profiled slider plate has three of edges 33, 35 and 37 bent at right angles to the surface of the slider plate. The central area of the profiled plate 32 has a cut opening 29. The remnant portion of the opening defining two cog profiles 28, adapted to engage with a complementary profiled driving lug.
Referring to Figure 7 the compact cylinder lock unit 14 is fitted to the circular central opening 9 provided on the cover plate by fasteners (not specifically shown). The cylinder lock unit includes a rotary central cylindrical core 18 fitted within the stationary outer cylinder housing 16. The inner core, adapted to receive a key shank of rectangular cross section, is prevented from rotating with reference to the cylinder housing by pressure pins 22 and lock pins 20 fitted in radial drilled holes in both the cylinder and housing. When a corresponding key 12 is inserted the key slot the profiles provided on the key align the locking pins inside the cylinder housing to allow rotation of the cylinder with reference to the cylinder housing. The operative rear end of the
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inner core has two profiled driving lugs 24 adapted to engage the cogs 28 profiled on the slider-dead bolt unit.
Referring to Figure 8, a resilient polymer lever 30 is securely mounted on lug 38 within the lock assembly to absorb the lateral play of the slider-dead bolt, to reduce noise generated and improve the smoothness of forward and reverse movement of the slider unit assembly.
By providing the lugs 44, flat seats 50, edge strip 15, slot 46, and lug 40 the lock casing 2 and the cover plate 4 are assembled to each other with out any fastener like nut bolts, screws or rivets.
Referring to Figure 4, the outer surface 11 of the lock casing and visible portion of the slider-bolt assembly are aesthetically finished.
Referring to Figure 5, the compact profile of a fully assembled lock in plan view is shown.
Referring to Figure 6, the compact profile of a fully assembled lock in front elevation view is shown.
Figure 12 shows one of the relative positions of the slider-bolt assembly with reference to the rotation of the key in the key slot. In this position the key is in its as inserted position defined as 0° of rotation. The slider-dead bolt is in its fully retracted position.
Figure 13 shows another relative position of the slider-bolt assembly with reference to the rotation of the key in the key slot. In this position the key has
13

been turned and is at 90o of key rotation. The slider-dead bolt is in a partly protruding position after completing approximately one fourth of its forward movement.
Figure 14 shows another relative position of the slider-bolt assembly with reference to the rotation of the key in the key slot. In this position the key has been turned and is at 180 of key rotation. The slider-dead bolt is in a partly protruding position after completing approximately half of its forward movement.
Figure 15 shows another relative position of the slider-bolt assembly with reference to the rotation of the key in the key slot. In this position the key has been turned and is at 270° of key rotation. The slider-dead bolt is in a partly protruding position after completing approximately three fourth of its forward movement.
Figure 16 shows another relative position of the slider-bolt assembly with reference to the rotation of the key in the key slot. In this position the key has been turned and is at 360° of key rotation. The slider-dead bolt is in a fully protruded position after completing its forward movement.
While considerable emphasis has been placed herein on the particular features of a drawer and cabinet lock the improvisation with regards to it, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiment without departing from the principles of the invention. These and other modifications in the nature of the invention or the preferred embodiments will be apparent to those skilled in the
14

art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

15

Documents:

1079-MUM-2007-ABSTRACT(29-10-2014).pdf

1079-mum-2007-abstract(9-7-2007).pdf

1079-mum-2007-claims(9-7-2007).pdf

1079-MUM-2007-CLAIMS(AMENDED)-(29-10-2014).pdf

1079-MUM-2007-CLAIMS(AMENDED)-(4-3-2013).pdf

1079-MUM-2007-CLAIMS(MARKED COPY)-(4-3-2013).pdf

1079-MUM-2007-CORRESPONDENCE(18-10-2010).pdf

1079-MUM-2007-CORRESPONDENCE(3-1-2014).pdf

1079-mum-2007-correspondence(30-5-2008).pdf

1079-mum-2007-correspondence-received.pdf

1079-mum-2007-descripiton (provisional).pdf

1079-mum-2007-description(complete)-(9-7-2007).pdf

1079-mum-2007-drawing(9-7-2007).pdf

1079-mum-2007-drawings.pdf

1079-mum-2007-form 18(30-5-2008).pdf

1079-mum-2007-form 2(9-7-2007).pdf

1079-mum-2007-form 2(title page)-(complete)-(9-7-2007).pdf

1079-mum-2007-form 2(title page)-(provisional)-(6-6-2007).pdf

1079-MUM-2007-FORM 26(29-10-2014).pdf

1079-MUM-2007-FORM 26(4-3-2013).pdf

1079-mum-2007-form 5(9-7-2007).pdf

1079-mum-2007-form-1.pdf

1079-mum-2007-form-2.doc

1079-mum-2007-form-2.pdf

1079-mum-2007-form-26.pdf

1079-mum-2007-form-3.pdf

1079-MUM-2007-MARKED COPY(29-10-2014).pdf

1079-MUM-2007-PETITION UNDER RULE-137(29-10-2014).pdf

1079-MUM-2007-REPLY TO EXAMINATION REPORT(4-3-2013).pdf

1079-MUM-2007-REPLY TO HEARING(29-10-2014).pdf

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Patent Number

263640

Indian Patent Application Number

1079/MUM/2007

PG Journal Number

46/2014

Publication Date

14-Nov-2014

Grant Date

11-Nov-2014

Date of Filing

06-Jun-2007

Name of Patentee

JOSHI SALIL PRABHAKAR

Applicant Address

J-61, MIDC,BHOSARI, PUNE-411 026.

Inventors:

#	Inventor's Name	Inventor's Address
1	JOSHI PRABHAKR ANANT	J-61, MIDC,BHOSARI, PUNE-411026.
2	JOSHI SALIL PRABHAKAR	J-61, MIDC,BHOSARI, PUNE-411 026.

PCT International Classification Number

A47B88/04

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA