GB2435993A

GB2435993A - Hatch for a security door

Info

Publication number: GB2435993A
Application number: GB0604727A
Authority: GB
Inventors: Andrew Peter Morris
Original assignee: CELL SECURITY Ltd
Current assignee: CELL SECURITY Ltd
Priority date: 2006-03-08
Filing date: 2006-03-08
Publication date: 2007-09-12
Also published as: GB0604727D0

Abstract

A hatch arrangement for a security door comprises a panel 11 secured between guides (14, 15, Figure 2). Each guide has a channel (16) to accommodate the panel with only sliding freedom such that the panel can be displaced between first and second positions. There is no apparent gap between the panel and the channel. The panel and the channels are made from materials resistant to wear. The guides and panel may be made of aluminium. The panel may be steel with aluminium edges. The edges of the panel and the channels may be accurately machined and matched. Spring loaded latches 19 arranged on a nudge bar 24 and urged in a direction perpendicular to the panel to engage notches (18) in the channels may be provided to locate the panel in its first and second positions. The edges of the panel may be rebated on one side. The panel may include a replaceable window 20. The panel is preferably located flush on one side of an aperture in a door to present a flat surface to the door leaving no gaps. A cover member made of the same material as the panel may be provided around the aperture edge of the door.

Description

A Hatch Arrangement The present invention relates to hatch arrangements

and more particularly to hatch arrangements utilised in security doors used in prisons, police cells and secure hospitals.

It is a necessity to provide secure accommodation in the form of prison cells and rooms in which persons can be securely contained when arrested by duly authorised authorities or when a danger to themselves and the public.

In such circumstances the doors must be relatively robust and able to withstand violent attack and hard usage. Nevertheless, it will be understood that it is also necessary to monitor restrained individuals regularly to ensure that they have not harmed themselves and provide food and water etc. It will be understood that rather than opening each door in a block of cells it is more convenient to provide hatch arrangements which can be prepared to open apertures in the doors through which food and water can be passed. In such circumstances, hatch arrangements will typically have at least two positions, one with the hatch closed, and one with the hatch open to expose the aperture in the door through which communication and food/water can be passed. It is also convenient to provide an intermediate position where a transparent window is located over the aperture in the door to enable viewing of the individual without opening the hatch arrangement for simple observation or to ensure that it is safe to open the aperture.

Previously, hatch arrangements have provided a panel with rubber or plastic guides along which the panel slides between the various positions as described above. Unfortunately, such plastic and rubber guide channels wear in use such that a gap is created between the panel and the door. It will be understood that doors in prison cells are generally used for a long period of time and therefore wear between the panel and the door can create a significant gap into which a vulnerable prisoner may insert a ligature upon which they may hang themselves in an attempted or successful suicide.

In accordance with aspects of the present invention there is provided a hatch arrangement for a security door, the arrangement having a panel secured between guides and displaceable between at least a first position and a second position, each guide having a channel to accommodate the panel with only slide freedom along the channel and no apparent gap between the panel and the channel, the channels and the panel at least where captured by the channel being made from material resistant to erosion in use by slide movement of the panel in the channel.

Typically, the panel is associated with a latch displaceable away from the panel. Generally, the displacement is substantially perpendicular to the panel. Possibly, the latch is biased to displacement away from the panel by a mechanical spring. Typically, the latch incorporates a nudge bar to actuate displacement of the latch.

Generally, the channels incorporate notches engaged by the latch.

Generally, the channels incorporate respective notches to engage the latch at least at the first and the second position.

Possibly, the panel has edges which are rebated to engage the channel. Generally, the rebate is to one side of the panel in order to present a flat surface.

Typically, the panel incorporates a viewing window. Generally, the viewing window is secured in an aperture in the panel in order to avoid compromising engagement between the panel and the guides. Generally, the viewing window is secured in the panel through robust fastening. Potentially, the robust fastenings can be released in order to replace the window.

Generally in accordance with the present invention the hatch arrangement also incorporates a door with an aperture closed by the panel.

Generally, one side of the panel is arranged to be flush with aperture edges in the door to limit any gap there between. Generally, the panel is to one side of the aperture.

Generally, the panel is made from a flat metal sheet. Typically, the metal sheet is aluminium. Normally, the panel is sufficiently thick to have adequate mechanical strength to avoid distortion under percussive and impact loads at least when secured between the guides.

Generally, the guides are made from a metal. Typically, the metal is aluminium. Generally, the guides are secured to the door by bolts.

Advantageously, the panel at least where captured and the channels are made from the same material to inhibit differential slide erosion there between. Possibly, the door at least about the aperture edge is formed from, or is associated with, a cover member formed from the same material as the panel.

Embodiments of the present invention will now be described by way of example and with reference to the accompanying drawings in which: Fig. 1 is a schematic illustration of a hatch arrangement secured to a door in accordance with aspects of the present invention; Fig. 2 is an exploded illustration of a hatch arrangement in accordance with aspects of the present invention; Fig. 3 is an exploded view of a panel as depicted in Fig. 2; and, Fig. 4 is an exploded view of a latch in accordance with aspects of the present invention.

Hatch arrangements, as indicated, are provided in security doors in order to enable a hatch aperture to be opened for access to a cell rather than necessitating opening the door itself and also to allow visual inspection through a transparent window if provided. Fig. 1 provides a schematic cross sectional illustration of a security door 1 incorporating a hatch arrangement 2.

Thus, the door is secured in a door frame 3 itself located within a wall 4 to typically divide a cell side 5 from a corridor or passageway side 6. The hatch arrangement 2 is displaceable in order to open a hatch aperture 7 in the door 1 and is typically displaceable in the direction of arrowheads A. In accordance with aspects of the present invention the arrangement 2 is provided such that a gap 8 exaggerated for illustration purposes between the arrangement 2 and the door 1 around the hatch aperture 7 is substantially eliminated to prevent any gap providing an anchorage for a ligature. It will be understood that as the arrangement 2 must allow a panel to slide across the hatch aperture 7 there is the potential for wear exacerbating any gap 8 as well as between the panel and other parts of the arrangement 2. Nevertheless, for ease of operation previously plastics and rubber guide channels have been used which will wear exacerbating any gap and therefore the potential to provide anchorages for ligatures.

In accordance with aspects of the present invention a hatch arrangement is provided for security doors which has a limited, if any, gap between the panel and associated channels in guide members. This limited gap is provided by appropriate high tolerance machining such that there is only slide freedom between edges of a panel captured by the channels of the guide members. Thus, no plastics or rubber surface to surface engagements are provided which may wear during the in use slide operation of the hatch arrangement.

Fig. 2 provides an exploded illustration of a hatch arrangement in accordance with aspects of the present invention. Thus, a panel 11 will be secured in use through edges 12, 13 respectively engaging guide members 14, 15 through channels 16.

The guide members 14, 15 will be robustly secured to a security door in use through bolts 17 which will ensure that the guide members 14, 15 are accurately located but can also be removed for maintenance. The guide members 14, 15 will also incorporate notches 18 which will be engaged by latches 19 associated with the panel 11.

The panel 11 typically in use will incorporate a viewing window 20 itself secured on the external side relative to a door upon which the arrangement is secured. The viewing window 20 will typically be secured through bolts or rivets to enable the transparent plastic or other material to be removed if it should become crazed or cracked. As can be seen, the viewing window 20 is generally formed in an aperture of the panel 11 such that the viewing window does not impinge upon the general operation of the arrangement.

In use information panels 21, 22 will also generally be used to indicate panel 11 position and therefore status with regard to the hatch arrangement.

The edges 12, 13 as indicated above, are captured by the channels 16.

Typically, the edges 12, 13 are rebated to reduce the general thickness of the panel 11. It will be understood that the thickness of the panel 11 is provided such that the panel will not distort in use when subject to violent percussive impacts but such thickness may create problems with regard to accurate snug association and capture between the edges 12, 13 and the channels 16. It will also be understood that by milling or other machining to provide the rebated edges 12, 13, and similarly through accurate matching or routing of the channels 16, close tolerance specification between the thickness of the edges 12,1 3 and the channel 16 can be provided. Such close tolerance is important such that only slide freedom of the panel 11 along the channels is allowed. In such circumstances there will be substantially no gap between the panels 11 and the channel 16 in which a ligature can be anchored.

In assembly the panel 11 will be presented to a door and the guide members 14, 15 moved inwardly in the direction of arrowheads B in order that the panel 11 is captured. It will be understood that previously appropriate screw holes will have been provided in the door to allow insertion of the bolts 17. In such circumstances the guide members 14, 15 will generally be substantially parallel and the slide range determined by the length of the channel 16. It will also be understood that by rebating the edges 12, 13 an edge is provided which may guide the slide movement in use.

Fig. 3 provides an exploded illustration of the panel 11. Thus, as can be seen, the transparent viewing window 20 is secured through screws or rivets 23 and the latch 19 comprises a nudge bar 24 with associated lugs to create the latches 19. The nudge bar 24 can be depressed in order to move the latches 19 substantially perpendicular to the plane of the panel 11. It will be noted that the substantive part of the panel 11 comprises a flat sheet 25 of appropriately thick material to provide resistance to distortion under percussive loads. The sheet 25 incorporates a viewing aperture 26 which, as illustrated previously, is generally closed by the viewing window 20.

Fig. 4 provides an exploded view of the hatch mechanisms incorporating latches 19 engaging the notches 18 (Fig. 2) as described previously. As can be seen, the mechanism 27 is relatively robust and generally comprises the nudge bar 24 in the form of a box section on which a solid robust cross member 28 is secured to enable pivot around a pivot end 29 for the nudge bar 24. In such circumstances in use as indicated above, the nudge bar 24 can be depressed in order to displace the latches 19 against a bias typically in the form of mechanical springs 29. When depressed the latches 19 will disengage the notches 18 and allow the panel to slide in the channels 16.

As indicated above, elimination of gaps between the panel 11 and the door as well as between the panel and its guide channels is achieved through initial close manufacturing tolerances and matching between the channels 16 and edges 12, 13. However, hatch arrangements may be subject to extensive use and have a long lifetime such that erosion of materials from which the edges 12, 13 and channels 16 are formed can create a significant problem with regard to gaps within which ligatures can be anchored. Clearly, one previous approach was to attempt to replace rubber slide surfaces in the channels 16, but the nature of hatch arrangements used with regard to security doors means that such rubber and plastic materials are robustly secured and therefore simple replacement is difficult. This is necessary to avoid removal of these plastic and rubber materials both to create an even greater gap 4 and to resist escape attempts. Aspects of the present invention ensure that the materials from which the sheet 25 and at least the edges 12, 13 are formed as well as the channels 16 are such that erosion resistance is substantially eliminated maintaining the benefits of accurate machining and matching between the edges 12,1 3 and the channels 16.

Generally, the guide members 14, 15 are made from a metal and most typically aluminium such that the channel 16 can be accurately machined. It will also be appreciated that when formed from aluminium the guide members 14, 15 are relatively light and therefore facilitate accurate location both during installation and operation upon a secure door. It will be understood that heavy guide members 14, 15 may sag slightly and therefore create movement when secured to a door. However, it is the edge 12, 13 to channel 16 association which is most important and therefore where necessary heavier steel materials may be utilised with regard to the guide members 14, 15 and the channel 16 provided as inserts subsequently accurately machined as necessary for matching with the edges 12, 13.

As indicated above, the edges 12, 13 are accurately matched with their respective channels 16 in the guide members 14, 15. Normally, such matching will be performed with hatch arrangements at the manufacturing site and that set comprising the guide members 14, 15 and panel 11 paired thereafter possible through appropriate match serial numbering or otherwise.

In any event the edges 12, 13 will be captured by the channel 16 with only slide freedom and limited, if any, gap allowed. It will be understood that a skim of a lubricant may be applied to the edges 12, 13 upon initial installation and due to the close tolerance between the edges 12, 13 and channels 16 that lubricant will be substantially retained by capillary action.

The sheet 25 will generally be formed from a metal in order that the thickness of the sheet 25 will be acceptably wide for percussive deformation resistance. Typically, the metal will be aluminium but, as previously, the most important factor is that the edges 12, 13 can be accurately machined for matching with the channel 16. In such circumstances, the edges 12, 13 alone may be formed from aluminium appropriately secured to a more robust metal such as steel.

It will be appreciated if the guide members 14, 15 or at least the channel 16 and the edges 12, 13 are formed from the same material, that is to say aluminium there is a reciprocity with respect to erosion resistance and therefore generally the edges 12, 13 will not erode the channel 16 and vice versa.

A indicated above, generally it is preferable for panels 11 and guide members 14, 15 to be matched during manufacture. In such circumstances it will be understood that closer tolerances between the edges 12, 13 and the channel 16 can be achieved. The prior approach of assembling hatch arrangements on security doors on site necessitated standardisation of components and welding of elements to security doors which may create problems with regard to tolerances etc. By provision of the present hatch arrangement it will be appreciated that more ease of assembly to a security door as well as replacement of hatch arrangements can be achieved through the use of bolts 17 and rivets etc. In such circumstances hatch arrangements in accordance with aspects of the present invention should provide greater ease with regard to installation and maintenance. Whole hatch arrangements can be replaced and maintained rather than lowest common denominator tolerance with respect to standardised components.

Whilst endeavou ring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

CLAIMS

1 A hatch arrangement for a security door, the arrangement having a panel secured between guides and displaceable between at least a first position and a second position, each guide having a channel to accommodate the panel with only slide freedom along the channel and no apparent gap between the panel and the channel, the channels and the panel at least where captured by the channel being made from 1 0 material resistant to erosion in use by slide movement of the panel in the channel.

2. An arrangement as claimed in claim I wherein the panel is associated with a latch displaceable away from the panel.

3 An arrangement as claimed in claim 2 wherein the latch displacement is substantially perpendicular to the panel 4 An arrangement as claimed in claim 2 or claim 3 wherein the latch is biased to displacement away from the panel by a mechanical spring.

An arrangement as claimed in claim 2, claim 3 or claim 4 wherein the latch incorporates a nudge bar to actuate displacement of the latch. S. * .

6. An arrangement as claimed in any of claims 2 to 5 wherein the * SS S channels incorporate notches engaged by the latch. * S*

* S. S * S 7 An arrangement as claimed in claim 6 wherein the channels incorporate respective notches to engage the latch at least at the first ... 30 and the second position S S* S

S S S...

8 An arrangement as claimed in any preceding claim wherein the panel has edges which are rebated to engage the channel.

9 An arrangement as claimed in claim 8 wherein the rebate is to one side of the panel in order to present a flat surface.

An arrangement as claimed in any preceding claim wherein the panel incorporates a viewing window 11 An arrangement as claimed in claim 10 wherein the viewing window is secured in an aperture in the panel 12 An arrangement as claimed in claim 10 or claim 11 wherein the viewing window is secured in the panel through a robust fastening.

13 An arrangement as claimed in claim 12 wherein the robust fastenings can be released in order to replace the window.

14 An arrangement as claimed in any preceding claim wherein the hatch incorporates a door with an aperture closed by the panel An arrangement as claimed in claim 14 wherein one side of the panel is arranged to be flush with aperture edges in the door to limit any gap there between.

*.... 25 S...

16 An arrangement as claimed in claim 14 or claim 15 wherein the panel : * .: is to one side of the aperture * 17. An arrangement as claimed in any preceding claim wherein the panel *. 30 is made from a flat metal sheet. ***. * . *e.

18 An arrangement as claimed in claim 17 wherein the metal sheet is aluminium.

19 An arrangement as claimed in any preceding claim wherein the panel is sufficiently thick to have adequate mechanical strength to avoid distortion under percussive and impact loads at least when secured between the guides An arrangement as claimed in any preceding claim wherein the guides 1 0 are made from metal 21 An arrangement as claimed in claim 20 wherein the metal is aluminium.

22 An arrangement as claimed in any preceding claim wherein the guides 1 5 are secured to the door by bolts.

23 An arrangement as claimed in any preceding claim wherein the panel at least where captured and the channels are made from the same material to inhibit differential slide erosion there between.

24 An arrangement as claimed in any preceding claim wherein the door at least about the aperture edge is formed from, or is associated with, a cover member formed from the same material as the panel * S 25 A hatch arrangement for security doors substantially as hereinbefore * ** * described with reference to the accompanying drawings S. ** * S. S * * * . 26 Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the .. 30 same invention as any of the preceding claims. *.*. * S S..