GB2522633A

GB2522633A - Preventing entry via nightlatch without removing key

Info

Publication number: GB2522633A
Application number: GB1401556.4A
Authority: GB
Inventors: Charles Kenneth Lacey
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-01-30
Filing date: 2014-01-30
Publication date: 2015-08-05
Also published as: GB201401556D0

Abstract

Four methods of reminding someone that they have left a key in the lock are disclosed. Firstly, Drawing 1 discloses a key with a portion that engages with a clip (Fig 4), completing a circuit which activates a visible or audible alarm inside the premises, until the key is removed. The second method (Drawing 2 Figs 1-3) uses a bolt (3) operated by a solenoid on the inner face of the door, activated using the spring clip method, whilst the key is in the lock the bolt is forced into the extended position and catches on a striker plate (D3 F1-3 5). When the key is removed the bolt can be withdrawn and can pass by the striker plate. Method three (Drawing 3 Figs 4-6) uses a solenoid in a similar way but a retaining bar (D3 F6 7) engages with the bolt (3) preventing the door opening sufficiently until the key is withdrawn. Method four (Drawing 3) uses a mechanism including an ejector block (4 D3 F1) which ejects the key if the keyholder's grip is released, which then falls through a hopper (D3 F6 13) onto the inner floor when the door is opened.

Description

Preventing entry via nightiatch without removing key This invention relates to a means of preventing a keyholder from entering a premises by means of a nightlatch without first removing the key.

Homes are often burgled and ears etc stolen because a keyholder enters the premises, then closes the door without having removed the key or bunch of keys, providing an ideal opportunity for a passing thief.

According to the present invention there is provided a method of preventing a keyholder entering a premises by means of a nightlatch without removing the key from the lock Four alternative methods of achieving this objective are described, which are briefly as follows-Method 1-By means of a visual or audible alarm unit which is activated when the key is inserted into the lock.

Method 2-By preventing the door, once opened, from subsequently being closed until the key is withdrawn.

Method 3-By preventing the door from being opened sufficiently to allow entry until the key is withdrawn.

Method 4-By means of a mechanism which ejects the key from the latch if the keyholder releases his/her grip on the key instead of withdrawing it manually.

A specific example of each method will now be described, withhe aid if the enclosed drawings, in which-Drg 1 shows the mechanism required within the lock cavity essential to methods 1, 2, and 3.

Drg 2 shows the requirements on the inner face of an external door essential to methods 2 and 3.

Drg 3 shows the requirements on the outer face of an external door, essential to method 4.

Note that the power source and any necessary wiring are omitted for clarity on drgs 1 and 2.

Description

Method 1-Drg 1 fig 1 shows a longitudinal section thro a typical cylinder lock installed into a wooden door with tumblers etc omitted and key withdrawn, comprising-cylinder housing 1, cylinder 2, and turning bar 3 which projects thro into the latch casing. Spring clip 4 is secured to, but insulated from the inner end of the cylinder. Latchkey 5 (fig 2) terminates in a plain flat portion 6 which engages with the spring clip when the key is inserted to it's operating depth. The spring clip and the housing are wired to the opposing terminals of a low voltage visual or audible alarm unit (not detailed) located in a prominent position inside the premises.

Inserting the key into the cylinder completes the circuit via spring clip/key/cylinder and housing, thus activating the alarm, which remains activated until the key is withdrawn.

Fig 3 shows a cross-section at arrow A-A, and fig 4 details of the spring clip.

Note that this mechanism is identical to that required to activate the solenoid in methods 2 and 3.

Method 2-referring to Drg 2-Fig 1 shows the inner face of entrance door, comprising-door I and frame 2. Bolt 3 is housed within solenoid 4. the bolt is projected outwards upon activation of the solenoid as described above. The bolt in fig 1 is shown in the neutral (dc-activated) position.

Fig 2 shows a sectional plan view with the solenoid activated and the bolt partly projected, but arrested by making contact with striker plate 5, secured to the frame.

Fig 3 shows a fUrther plan view with the door slightly opened, the bolt fUlly extended beyond the face of the striker 1atc, preventing the door being closed until the key is withdrawn, allowing the bolt to return to neutral.

Method3 6 Drg 2, fig 4 shows the inner face of an entrance don 1>frame 2, bolt 3, and solenoid 4. which operate as described above. A "U" shaped orackàis secured to the frame, offset from the plane of the door (fig 6), retaining bar 7 is suspen&d from pivot 8.

The bolt is shown in the neutral position (drawn fUll), and in the extended position (drawn dotted), between the frame and retaining bar when activated.

When the door begins to open the bolt makes contact with the retaining bar, pushing it to the horizontal until the key is withdrawn, allowing the bar to fall back to vertical.

Failure to withdraw the key within a pre-set angular opening will result in the bolt being arrested by the hooked end until the key is vithdrawn.

Fig 5 shows an end view as seen from the opening jamb, showing the profile of the retaining bar and the bolt extended before opening.

Fig 6 shows a sectional plan from above the mounting bracket, showing the maximum opening possible with the key still inserted, and the offset angle between retaining bar and door to avoid losing contact with the bolt. -3-

Method 4-Refering to drg 3, Fig 1 shows a longitudinal section thro a typical cylinder loèk with tumblers etc omitted and key withdrawn, comprising-cylinder housing 1, cylinder 2, and turning bar 3, (cranked to allow partial rotation) projecting thro into the latch casing. Ejector block 4, (not sectioned) is shown as 4A-outer position with key removed, and 4B-iimer position when the key is inserted. Spiral torsion spring 5 (as used in clockwork products) with spindle 6, is secured to the ejector block, the block free to slide between A & B, the spring remaining in tension regardless of the block's position.

The cylinder has an open slot (keyhole) for it's ffill length, which aligns with a corresponding slot 7, in the lower portion of the housing, open for it's frill length except for portion 8 at it's outer end. Spindle 6 is secured within the lock cavity (not detailed). The key 9, (fig 2) is square ended to finish flush with the inner end of the cylinder, effectively providing a flat surface to prevent unwanted movement of the block during partial rotation of the cylinder.

In the event of the keyholder releasing his/her grip on the key (instead of withdrawing it manually) it is returned to vertical by the turning bar, and ejected by the block, falling onto the lid of a closed hopper.

Fig 2 shows a profile of the key, and fig 3 a section thro arrow B-B.

Fig 4 shows the outer face of an external door 11, frame 12, and hopper assembly 13 located below the cylinder. The hopper houses flap (or lid) 14 and hinge bar 15 terminating in lever 16, housed within recess 17 in the frame. The flap, hinge bar and lever are integral, the lever being set at right-angles to the plane of the flap so that with the door closed the lever is kept vertical against the outer face of the recess, which ensures that the flap remains horizontal (hopper closed) until the door is opened.

Fig 5 shows a sectional view below the lock with the door closed.

Fig 6 shows an end view of the edge of the door leaf and frame, with the door partially opened, allowing the flap to fall into the hopper and theJever to swing outwards (hopper open), allowing the key to fall thro the aperture 18 onto the internal floor.

Note This hopper and flap arrangement ensures against the key being stolen from outside, or becoming irretrievable by, once ejected, flilling thro the hopper before the door is opened.

Claims

Claims 1 A method of preventing a keyholder from entering a premises by way of a nightiatch, and closing the door without removing the key from the nightiatch.
2 A method as claimed in claim 1, whereby the keyholder is alerted to the situation by means of a visual or audible alarm located inside the premises.
3 A method as claimed in claim 1, whereby the door, once opened, cannot subsequently be closed until the key is removed from the lock.
4 A method as claimed in claim 1 whereby the door is prevented from opening sufficiently to allow entry until the key is removed from the lock.
A method as claimed in claim 1, whereby the key, if released from the keyholder's grip, is ejected from the lock.
6 A method as claimed in claim 5, whereby the key, once ejected, is allowed to fall into a hopper, and through the door leaf, to the inside of the premises.
7 A method as claimed in claim 6, with means of preventing the key, once ejected, from falling thro the hopper before the door is opened.
8 A method as claimed in claim 3, which is combined with the method specified in claim 2.Amendments to the claims have been filed as follows: * C-Preventing entry via nightiatch without removing key Claims 1. A method of preventing a keyholder from entering a premises by way of a nightiatch until the key is withdrawn from the lock. An internal bolt engages with a retaining bar when the key is inserted, preventing sufficient openi.n to allow entry. Access being allowed only when the bolt is disengaged by withdrawing the key. - 2. A method as claimed in claim 1, whereby the bolt is projected into the engagement position by a solenoid wired to terminals within the Jock cavity, which is activated by inserting the key into the lock. The bolt being disengaged when the solenoid is de-activated by withdrawing the key from the lock.3. A method as claimed in claims 1 & 2 substantially as described herel n, and as detailed on drawings 1 & 2.