GB2305962A - Lock mechanism - Google Patents

Abstract

The lock mechanism comprises a housing (10) for fitting to a face of a second member, eg a door, and contains a latch mechanism (20), and a knob (50) for fitting to a first member, eg a frame, which engages with and latches to the latch mechanism (20). The housing (10) comprises a rear face (40) for attachment to a face of the second member, the rear face (40) extending to form an aperture (30) to receive the knob (50). The housing (10) also has a keyhole (101), latch mechanism (20) comprising elongate members (21, 22) mounted on pivots (23, 24), and biasing means (90). The knob (50) engages the elongate members (21, 22) at a first side of the pivots (23, 24). A key means (140, 150) for insertion through the keyhole (101) exerts force on the elongate members (21, 22) at a second side of the pivots (23, 24) to rotate the elongate members (21, 22) about said pivots (23, 24) against the action of the biasing means (90) to an unlatched position.

Description

A LOCK MECHANISM The present invention relates to a lock mechanism for locking a first member to a second member moveable relative to the first member. More particularly, the present invention relates to a lock mechanism for locking hinged members such as doors or windows to a frame in which the hinged member is mounted.

There is a requirement for lock mechanisms for particularly doors and windows and the like which are self locking and can be opened by the simple action of a key arrangement. Such lock mechanisms are commonplace for child safety applications.

It has been identified by the inventor of this invention that there is a need for a simple lock mechanism which is particularly suited for a stable door. Commonly used bolts for stable doors suffer from the disadvantage that the horse can learn to retract the bolt thereby opening the door and enabling the horse to escape from the stable.

It is therefore an object of the present invention to provide a lock mechanism which is particularly suited as a stable door lock but which has a general application as a safety lock.

The present invention provides a lock mechanism for locking a first member to a second member moveable relative to said first member, the lock mechanism comprising a housing for fitting to a face of said second member and containing a latch mechanism, and a knob for fitting to said first member and for engaging with and latching to said latch mechanism, said housing having a rear face for attachment to a face of said second member, said rear face extending to form an aperture to receive said knob, said housing further having a keyhole, said latch mechanism comprising a pivot extending substantially perpendicularly to said rear face of said housing, an elongate member mounted on said pivot, biasing means to bias said elongate member in a latched position whereby said knob engages said elongate member at a first side of said pivot, a key means for insertion through said keyhole to exert force on said elongate member at a second side of said pivot to rotate said elongate member about said pivot against the action of said biasing means to an unlatched position, said housing including fixing means to fix said housing to said second member; said knob comprising a fixing arrangement for fixing said knob to said first member, a latch face extending from said fixing arrangement such that said latch face extends substantially perpendicularly to said first member in use, and a shoulder extending from said latch face, said shoulder having a sloping face for guiding said elongate member over said shoulder to said latched position on said latch face and a detent face adjacent said latch face.

The present invention provides a simple lock mechanism which requires the insertion of a key near one end of the elongate member to cause the rotation of the elongate member about the pivot thereby unlatching the other end of the elongate member from the latch face of the knob.

In a preferred embodiment of the present invention the knob has a second latch face and a second shoulder like said latch face and said shoulder respectively, said latch face and said shoulder lying on one side of said knob and said second latch face and said second shoulder lying on an opposite side of said knob in a mirror symmetrical arrangement, said latch mechanism comprising a second pivot and a second elongate member like said pivot and said elongate member respectively, said elongate members being arranged to be latched on said latch face and said second latch face respectively, said biasing means comprising a biasing arrangement to bias said elongate members towards one another on said first side of said pivots, said housing having a second keyhole, said keyhole and said second keyhole being in opposed faces of said housing, said key means being arranged for insertion through the opposed keyholes to exert a force on said elongate member on said second side of said pivots to move second ends on said second side of said pivots towards one another thereby moving first ends on said first side of said pivots away from one another and into an unlatched position.

This preferred embodiment provides a simple symmetrical arrangement. Preferably the key means comprises two first peg members for insertion through the keyholes and two second peg members arranged within the housing at the base of the keyholes. Each of the second peg members has an enlarged head for engagement with the second side of the elongate members and the first peg members are shaped to engage the second peg members to exert a force on the second sides of the elongate members. Conveniently, the two elongate members can be arranged parallel to one another in the latched position.

In one convenient arrangement of the knob, fixing arrangement can comprise a base plate having holes to allow the base plate to be fixed to the first member.

The latch faces can comprise a cylindrical portion extending substantially perpendicularly from the base plate and a frustoconical portion forming the shoulder and extending coaxially from the cylindrical portion.

and extending coaxially from the cylindrical portion.

The diameter of a base of the frustoconical portion adjoining the cylindrical portion being greater than the diameter of the cylindrical portion.

An embodiment of the present invention will now be described with reference to the drawings, in which:- Figure 1 is a schematic perspective front view of the latch mechanism according to one embodiment of the present invention; Figure 2 is a front sectional view of the lock mechanism of Figure 1; Figure 3 is a perspective view of the knob of the latch mechanism of Figure 1; and Figure 4 is a perspective rear view of the lock mechanism of Figure 1.

Referring now to the drawings, the lock mechanism in accordance with one embodiment of the present invention comprises a housing 10 containing a latch mechanism 20. As can be seen in Figure 4, the housing 10 has an aperture 30 in a rear face 40 thereof. The aperture 30 is shaped to receive a knob 50 for engagement of the knob 50 with the latch mechanism 20.

The housing 10 is provided with bolts 60 for attachment to the stable door with the aperture 30 extending from the edge of the door. The knob 50 has a base plate 70 for fixing to the door frame surrounding the stable door. The base plate 70 can be fixed to the door frame by screws through the screw holes 80 in the base plate 70. When the door is hingedly moved to its close position the base plate 20 of the knob 50 fits into the aperture 30 and the knob 50 engages and latches with the latch mechanism 20. Since the knob is then enclosed within the housing 10, the lock mechanism is secure since there is no access to the fixing arrangement of the knob or of the housing 10. The bolts 60 can only be accessed from inside the door.

The latch mechanism 20 comprises two flat elongate and parallel members 21 and 22 which extend within the housing. Each elongate member 21 and 22 is held within the housing 10 by a pivot 23 and 24. The pivots 23 and 24 are cylindrical and extend for the width of the housing 10 from the rear face to a front face thereof. The pivots 23 and 24 are secured by coaxial pegs 25 and 26 at each end, in holes in the front and rear faces of the housing 10. The pivots 23 and 24 have slots cut therein to receive and hold the elongate members 21 and 22 and allow the pivotal motion thereof.

The elongate members 21 and 22 are biased by springs 90 to urge together the ends of the elongate members 21 and 22 which extend to a position adjacent to the aperture 30. Although in this embodiment tensional springs 90 are shown as being provided at the end of the elongate members 21 and 22 adjacent the aperture 30, in an alternative arrangement compressional springs could be provided at the other ends of the elongate members 21 and 22.

At the ends of the elongate members 21 and 22 remote from the aperture 30, pegs 100 and 110 are provided within respective peg housings 120 and 130.

Each peg 100 and 110 comprises a cylindrical stem 101 and a cylindrical head 102 of enlarged diameter. The cylindrical stem 101 fits within a cylindrical recess within the respective peg housings 120 and 130. The cylindrical head 102 of each peg 100 and 110 lies outside the peg housings 120 and 130 and engages with ends of the elongate members 21 and 22 remote from the aperture 30.

The pegs 100 and 110 are arranged in mirror symmetrical positions and are operated on by key pegs 140 and 150. The key pegs include a head 141 and a cylindrical stem 142. The stem 142 of the key pegs 140 and 150 can engage with the stem 101 of the pegs 100 and 110 in order to transfer a force to the elongate members 21 and 22 in order to cause the pivotal motion of the elongate members 21 and 22 about the pivots 23 and 24 against the action of the bias springs 90. This pivotal motion of the elongate members 21 and 22 moves the latch mechanism into an unlatched position whereas the bias springs 90 maintain the latch mechanism 20 in a latched position.

As can clearly be seen in Figure 3, the peg 50 includes a cylindrical latch face 160 extending substantially perpendicularly from the base plate 70.

A further cylindrical portion 170 of enlarged diameter relative to the cylindrical latch face 160 is provided coaxially extending from the cylindrical latch face 160. Extending coaxially from the further cylindrical portion 170 is a frustoconical portion 180.

A method of operation of the latch mechanism 20 and the knob 50 will now be described.

When the door is brought to a close position within the frame, the housing 10 mounted on the door is moved such that the knob 150 enters the aperture 30 in the rear face 40. The frustoconical portion 180 of the knob 50 engages with the ends of the elongate members 21 and 22 adjacent to the aperture 30 and the force of the door being closed acts against the bias springs to urge the ends of the elongate members 21 and 22 apart, thereby allowing the ends of the elongate members 21 and 22 to ride up the frustoconical portion 180, over the enlarged cylindrical portion 170 and onto the cylindrical latch face 160 whereby the bias springs 90 urge the ends of the elongate members 21 and 22 to tightly engage the cylindrical latch face 160.The interface between the cylindrical latch face 160 and the enlarged cylindrical portion 170 acts as a detent preventing the latch mechanism 20 from being released by the knob 50. The latch mechanism 20 is therefore in its latch position and secures the door to the frame. In order to unlatch the latch mechanism 20, it is necessary for the key pegs 140 and 150 to engage with the pegs 100 and 110 to exert a force on the ends of the elongate members 21 and 22 remote from the aperture 30 in order to cause the pivotal motion of the elongate members 21 and 22 about the pivots 23 and 24 against the action of the bias spring 90.Once the ends of the elongate members 21 and 22 adjacent the aperture 30 have been moved sufficiently far apart to overcome the restraints of the detent, the latch mechanism 20 has reached its unlatched position and the knob 50 can be released by the opening of the door and therefore the movement of the housing 10 away from the knob 50.

Thus this arrangement provides for a simple lock mechanism which automatically moves to its latch position when the door is shut and can be operated by a simple key arrangement.

Although in this embodiment the key arrangement comprises key pegs 140 and 150, any key arrangement can be used which allows for the required force to be applied to the ends of the elongate members 21 and 22 remote from the aperture 30. It is possible to incorporate an electronic code system to operate the lock mechanism.

The housing 10 can be formed of any suitable material such as cast aluminium alloy. The housing 10 can be bolted to the door using the bolts 60 shown in Figure 4 or it can be fixed to the door using any type of fixing arrangement. Similarly, although the knob has been described as being fixed to the frame by screws, any method of fixing the knob 50 to the frame can be used, e.g. aluminium rivets.

Claims (6)

1. A lock mechanism for locking a first member to a second member moveable relative to said first member, the lock mechanism comprising a housing for fitting to a face of said second member and containing a latch mechanism, and a knob for fitting to said first member and for engaging with and latching to said latch mechanism; said housing having a rear face for attachment to a face of said second member, said rear face extending to form an aperture to receive said knob, said housing further having a keyhole, said latch mechanism comprising a pivot extending substantially perpendicularly to said rear face of said housing, an elongate member mounted on said pivot, biasing means to bias said elongate member in a latched position whereby said knob engages said elongate member at a. first side of said pivot, a key means for insertion through said keyhole to exert force on said elongate member at a second side of said pivot to rotate said elongate member about said pivot against the action of said biasing means to an unlatched position, said housing including fixing means to fix said housing to said second member; said knob comprising a fixing arrangement for fixing said knob to said first member, a latch face extending from said fixing arrangement such that said latch face extends substantially perpendicularly to said first member in use, and a shoulder extending from said latch face, said shoulder having a sloping face for guiding said elongate member over said shoulder to said latched position on said latch face and a detent face adjacent said latch face.

2. A lock mechanism as claimed in Claim 1 wherein said knob has a second latch face and a second shoulder like said latch face and said shoulder respectively, said latch face and said shoulder lying on one side of said knob and said second latch face and said second shoulder lying on an opposite side of said knob in a mirror symmetrical arrangement, said latch mechanism comprising a second pivot and a second elongate member like said pivot and said elongate member respectively, said elongate members being arranged to be latched on said latch face and said second latch face respectively, said biasing means comprising a biasing arrangement to bias said elongate members towards one another on said first side of said pivots, said housing having a second keyhole, said keyhole and said second keyhole being in opposed faces of said housing, said key means being arranged for insertion through the opposed keyholes to exert a force on said elongate member on said second side of said pivots to move second ends on said second side of said pivots towards one another thereby moving first ends on said first side of said pivots away from one another and into an unlatched position.

3. A lock mechanism as claimed in Claim 2 wherein said fixing arrangement comprises a base plate having holes to allow said base plate to be fixed to said first member, said latch faces comprising a cylindrical portion extending substantially perpendicularly from said base plate, and a frustoconical portion forming said shoulder and extending coaxially from said cylindrical portion, the diameter of a base of said frustoconical portion adjoining said cylindrical portion being greater than the diameter of said cylindrical portion.

4. A lock mechanism as claimed in Claim 2 or Claim 3 wherein said key means comprises two first peg members for insertion through said keyholes and two second peg members arranged within said housing at the base of said keyholes and each having an enlarged head for engagement with said second ends of said elongate members, said first peg members being shaped to engage said second peg members to exert a force on said second ends of said elongate members.

5. A lock mechanism as claimed in one of Claims 2 to 4 wherein said elongate members are arranged parallel to one another in the latched position.

6. A lock mechanism substantially as hereinbefore described with reference to the accompanying drawings.