Security door

Abstract

A security door 100 with a core sheet 110 and a door edge reinforcement column 120 formed of two channels, along with a facing sheet 130a, 130b covering the core sheet with bracing ribs (Fig 3d, 132)

Description

Technical Field The present invention relates to a security door and also to a security door frame. Together, the door and frame provide a door set. The present invention also provides methods of manufacturing a security door and frame. Background High security doors are often made from metal such as steel to provide strength against attack. Such doors may be used for protection of properties containing high value goods and for protecting doors to significant infrastructure. European, US, UK and other standards set out test requirements for resistance to physical attack, fire, ballistic attack and blasts. For example, steel security doors may be fabricated from a wooden structure which is covered in steel sheet. Alternatively, such doors may be manufactured from a square section tubular steel to form a frame and again covered in sheet steel. Hardened grades of steel may be used. However, security doors may be time consuming to build and are heavy when built which makes transportation costs high. Accordingly, it is desirable to provide security doors and methods of manufacture that are faster and lower cost. A high level of skill is usually required to manufacture a door set. A door provided in kit form that is easily assembled (even on site) by a lower skilled person(s) could be logistically advantageous. Preferably, improved security doors also achieve enhanced security and strength ratings. Summary of the Invention The present invention provides a security door, such as strengthened or toughened security door. The security door comprises a core sheet, which may be a relatively thick flat metal sheet providing strength and rigidity to the door, preferably at the centre of the door. The core sheet may be considered to be a core reinforcing sheet. The security door further comprises a door edge reinforcement column formed of a first channel section and a second opposing section, at least the first channel section may have a U-shaped or C-shaped cross-section and the first section and second section together form the door-edge reinforcement column at the locking edge of the door. The door-edge reinforcement column may be configured for mounting a lock device for securing the door. For example, the dooredge reinforcement column may provide a strengthened edge to the door for mounting the lock device. The door-edge reinforcement column may be configured to have the lock device mounted therein, or may have the lock device fixed to it. The security door further comprises at least one facing sheet covering the core sheet, wherein bracing ribs are configured between the at least one facing sheet and the core sheet. The first channel section may be formed from an elongate flat sheet which is folded or bent to form a channel along the elongate length of the sheet, for example, the sheet having a U-shaped or C-shaped cross-section. The second opposing sheet may also be a similarly formed channel section or may be an elongate flat sheet. By forming a door of components that can be manufactured by cutting and folding or bending sheet metal such as sheet steel, the components may be manufactured anywhere that has a metal sheet cutting and folding facility. This means security doors which are heavy and bulky items to transport can be manufactured locally to the desired location at which they are expected to be installed. Furthermore, the structure provided by the security door described herein, in combination with the door frame described herein, meets many stringent national and international standards regarding security and safety etc. The first channel section and / or second opposing section may have U-shaped cross-sections, arranged opposing each other so as to form the column with a space therein for receiving the lock device. The at least one facing sheet may comprise a first facing sheet covering a first side of the core sheet and spaced from the core sheet by said bracing ribs and a second facing sheet covering a second side of the core sheet, opposite to the first side, with further bracing ribs between the core sheet and second facing sheet. The bracing ribs may have a top-hat shaped cross-section. The top-hat shaped cross-section may have a base resting against or in contact with the core sheet. The bracing ribs may comprise tabs at a first end which are fixed to the door-edge reinforcement column. The door-edge reinforcement column may have a substantially rectangular crosssection formed by the first channel section and second opposing section. The door may further comprise reinforcement plates spaced along the length of the column. The plates may be evenly or regularly spaced from each other along the column. The reinforcement plates may be arranged crossing the column supporting the four sides of the column against crushing. The reinforcement plates may comprise tabs engaging in holes or slots in each of the four sides of the rectangular column. The door-edge reinforcement column may comprise first anti-crush tubes spacing apart faces of the first channel section and the second opposing section. The first anticrush tubes may be provided locally to any furniture through fixings. The door may further comprise a viewing hole or window through the core sheet and the at least one facing sheet. The viewing hole or window may be supported by a second anti-crush tube. The door may further comprise the lock device, the lock device mounted in the reinforcement column between a first reinforcement plate crossing the column and a second reinforcement plate crossing the column. The first reinforcement plate and second reinforcement plate may form a column section space into which the lock device is mounted. The door may further comprise one or more filler plates arranged in the column section space. The one or more filler plates may be arranged to fill a space between the lock device and the first channel section or second opposing section. The one or more filler plates may have tabs located in slots or holes in the first reinforcement plate and second reinforcement plate. The door may further comprise: hinges fixed to the door at an opposing edge to the door edge reinforcing column; and hinge bolts fixed into the opposing edge and extending from the door for locating into corresponding holes in the frame for securing the opposing edge of the door to the frame when the door is closed. The door may further comprise a hinged edge reinforcement having a C-shaped cross-section and through which hinge fixings and the hinge bolts are located. The C-sections and / or bracing ribs may be formed by folding or bending flat metal sheet. Any of the bracing ribs, core sheet, first channel section, second opposing section and / or at least one facing sheet may be fixed together by rivets. The present invention further provides a security door frame, comprising first and second side jambs joined by a header jamb to form the security door frame, the first and second side jambs each comprising: one or more fixing plates for receiving fixings for mounting the frame, such as to a building, wall etc; an outer sheet layer, the outer sheet layer and one or more fixing plates forming the outer shape of the side jamb for receiving a door. The outer sheet layer may be bent or folded such that in combination with the fixing plates form a side jamb preferably having an L-shaped cross-section. For example, a door may close into an aperture formed between the first and second side jambs and the L-shaped cross-section may include a stop against which the door closes in the frame. The side jambs may comprise a first frame section and a larger second frame section, the first and second frame sections having channels along their lengths, for example, forming a U-shaped cross-section. The first frame section may be nested in the second frame section. The first and second frame sections may be positioned within the outer sheet layer with edges meeting the one or more fixing plates. A side wall of the first frame section may be arranged along an approximate middle upright line of the frame to support the side jamb, for example, against crushing. The side jambs may alternatively be called legs of the frame. The first and second frame sections may be formed of elongate flat sheets bend to form a channel section along its length. The door frame described herein, similarly to the door, may be manufactured using simple widely available processing steps allowing it be manufactured close to the location for installation. Hence, costly long-distance transportation costs for the frame may be avoided. The outer cross-section for receiving the door, may have an L-shaped crosssection, and forms the door jamb and stop of the door frame. The first and second frame sections may be arranged in the jamb part of the door frame, such as for supporting the jamb against crushing. The side wall of the first frame section may be aligned approximately to the inner edge of the stop of the frame. The security door frame may further comprise a third channel section, such as having a U-shaped cross-section, arranged in the stop of the frame with a side wall of the third frame section aligned approximately with the middle upright line of the frame. The security door frame may further comprise hinges fixed to one of the side jambs, wherein the outer sheet layer, first frame section and second frame section comprise aligned holes for receiving a hinge bolt for securing an edge of a door to the side jamb when the door is closed. Any one or more of: the first side jamb, second side jamb and header jamb, may comprise wind-out fixings to brace and adjust the alignment of the door frame during installation such as in a doorway. The first side jamb and second side jamb may comprise first fixing members and the header jamb may comprise second fixing members, and the first fixing members comprise slots or holes and the second fixing members comprise tabs slotted in to the slots or holes and bent over to secure one of the side jambs to the header jamb, or the first fixing members comprise tabs and the second fixing members comprise slots or holes, and the tabs are slotted in to the slots or holes and bent over to secure one of the side jambs to the header jamb. The folded tabs may be riveted to one of the side jambs or header jamb. The fixing plates comprise cut-outs into which are located the edges of the first frame section and second frame section. The side jamb may comprise further reinforcement in the region(s) where one or more bolt(s) for securing the door are received. The L-shaped cross-section of the side jamb may have an internal angle aligned with mid-line of the jamb. The present invention further provides a security door set comprising a security door as set out herein and a security frame as set out herein. The present invention provides a method of manufacturing a security door, comprising: assembling a core sheet to a first channel section; mounting a lock device in the first channel section; assembling a second section opposing the first channel section to form a door-edge reinforcement column; fitting one or more bracing ribs across the core sheet; and assembling at least one facing sheet to cover the core reinforcing sheet and the one or more bracing ribs. The method may further comprise assembling the at least one facing sheet covering the core sheet, the one or more bracing ribs and the door-edge reinforcement column. The at least one facing sheet may comprise a first facing sheet covering a first side of the door and may further comprise assembling a second facing sheet to the door, the second facing sheet covering a second side of the door. The method may further comprise arranging reinforcement plates into slots across the door-edge reinforcement column to support the four sides of the column. The method may comprise mounting the lock device into the first channel section by mounting the lock device with one or more filler plates to fill a space in the column between the locking device and the first channel section and second section. The present invention provides a method of manufacturing a security door frame comprising first and second door jambs joined by a header beam, the method comprising: forming each of the first and second doorjambs by: nesting a first frame channel section inside a second larger frame channel section. The first and section frame channel sections may have a U-shaped cross-section. The method further comprising: positioning the nested first and second channel sections inside a sheet layer forming the outer shape of the jamb; inserting one or more fixing plates into the outer sheet layer; and aligning a side wall of the first frame channel section to an approximate middle upright line of the jamb; and fixing the header beam across the tops of the first and second door jambs to form the security door frame. The outer sheet layer may be an elongate sheet folded to form an L-shaped outer cross-section, with the one of more fixing plates completing the L-shaped cross-section. The channel sections may be formed by cutting a metal sheet and folding to form the U-shaped channel sections. The present invention further provides a kit of parts for forming a security door, the kit of parts comprising: a core sheet; a first channel section and a second section configured for forming a door-edge reinforcement column such as for a locking edge of the door; at least one facing sheet for covering the core sheet; and bracing ribs configured for mounting between the at least one facing sheet and the core sheet. The present invention further provides a kit of parts for forming a side jamb or header jamb for a security door frame, the kit of parts comprising: one or more fixing plates for receiving fixings for mounting the frame; an outer sheet layer having longitudinal bends or folds, the outer sheet layer and one or more fixing plates form an outer shape of the side jamb for receiving a door; a first frame section and a larger second frame section, the first and second frame sections having channels along their lengths and the first frame section sized to be nested in the second frame section, the first and second frame sections sized to be positioned within the outer sheet layer and having edges configured to mount into the one or more fixing plate. The kits of parts described herein may be used to produce the security door, security door frame, door set and / or used in methods of manufacturing said items. Brief Description of the Drawings Embodiments of the present invention will now be described with reference to the accompanying drawings, of which: Figure 1 shows a security door set, from the inside or indoor side of the door, the figure shows a plan view and left and right side perspective views; Figure 2 shows a security door set, from the outside or outdoor side of the door, the figure shows a plan view and left and right side perspective views; Figures 3a-3d show details of the security door, with figure 3a showing a perspective view of the door, figure 3b showing a cross-section laterally through the door and figures 3c and 3d showing enlarged views of parts of the cross-section view; Figures 4a to 4g are perspective views showing a sequence of steps of assembly of the security door; Figures 5a-5d are perspective views of bracing ribs for the security door including at figure 5a the ribs attached to the door, at figures 5b and 5c enlarged views of the ends of the bracing ribs and at figure 5d a view of one bracing rib prior to assembly to the door; Figure 6 is a perspective view showing reinforcement of the door edge including reinforcement plates and filler plates; Figure 7 is a cross-section view through the reinforcement of the door edge showing anti-crush tubes; Figures 8a and 8b are cross-section views through door jambs of the door frame, with figures 8b showing wind-out fixings; Figures 9a-9c are further views of the door jambs with figures 9a and 9b respectively showing hinge and hinge bolts fitted to the door and hinge and hinge bolts against the jamb without the door shown, and figure 9c is a cross-section view through thee jamb and part of the door; Figure 10 is a perspective view showing the fixing of a side jamb to the header jamb; Figure 11 is a flow chart of a method of manufacturing a security door; and Figure 12 is a flow chart of a method of manufacturing a door frame for a security door. Detailed Description Figures 1 and 2 shows a security door respectively from a first side and from a second side. Figure 1 shows the inside facing side of the security door leaf 100 and door frame 200 forming a door set, and includes an emergency egress push bar type door release mechanism 10. The door egress mechanism releases bolts securing the door closed. In the arrangement of figure 1 the door is secured closed by a multi-point bolting mechanism 10 which throws and retracts bolts into the frame at three positions identified as A, B and C in figure 1. Other numbers of bolts may be provided such as a single bolt, two bolts, or more than three bolts. The figure shows the inside door face-on in the central image of the figure and in perspective view from the left and the right respectively in the side images, so as to show features of the door frame 200. The door leaf may comprise a viewing hole or window 195. The viewing hole or window is small so as not to significantly reduce the strength of the door leaf. The viewing hole or window 195 is sized for viewing through with one eye. The viewing hole may include a lens or transparent material to isolate the inside and outside from each other when the door is closed. Figure 2 shows the outside facing side of the security door leaf 100. Although we describe the two sides of the door as inside and outside the door set may be used internally between two spaces located inside a building, or may be used externally between two outdoor spaces. Hence, the terms “inside” and “outside” may be considered to be relative to the room or space the door set is securing. On the outside of the door for controlling entry is a handle 20 and a key lock 30. Insertion and turning of a matching key into the key lock releases handle and allows turning of the handle to release the one or more bolts, such as at points A, B and C. Alternatively, instead of a key lock and handle, electronic access control may be provided which requires input of a key code or scanning of a key card or key fob etc. Also shown in figure 2 are hinges 150 which hold the door leaf to the door frame and allow the door to open outwardly, that is towards the outside. By being hinged for outward opening the door closes against stops of the door jamb which acts to reduce a first attack option of physical assault pushing the door to open inwardly. We now describes aspects of the door and frame of the present invention. Figures 3a to 3d show aspects of a first embodiment of a security door. The door comprises a sheet which may form the core of the door. The sheet, or core sheet, may be arranged centrally in the door, for example halfway between the front and back faces of the door. Figure 3a is a perspective view of the door 100 showing the inside or indoor facing side of the door. Figure 3b shows the door 100 in cross-section with the core sheet 110 visible along the central plane of the door. Along the opening edge of the door is provided a door-edge reinforcement section or column, which may be a large tube having a substantially rectangular cross-section. This can be seen at 120 in figure 3b and is arranged along the right hand side, vertically in the door in figure 3a . The core sheet meets the door-edge reinforcement section. The core sheet and door-edge reinforcement column or section preferably extend the full height of the door and together span the width of the door. As shown in the cross-section of figure 3b the door-edge reinforcement column may be formed of one or more channel sections 121, 123. The channel section 121 may be II or C-shaped formed by bending or folding a flat material sheet such as a metal sheet. In figure 3b, the U-shaped channel section 121 meets a flat plate 122 covering the open top of the U-channel. A second U-shaped channel section 123 is inverted in comparison to U-shaped channel 121 and is placed over the flat plate 122 and U-channel 121. The second U-shaped channel section is slightly larger than that of 121 such that it fits over the U-shaped channel section 121 and flat plate 122. In embodiments, only first U-shaped channel and the flat plate may be used and the second U-shaped channel 123 may be omitted. Alternatively, the flat plate may be omitted and the first and second U-shaped channels are included. Where two U-shaped channels are used and the flat plate is omitted, one U-shaped channel section may be larger than the other such that one fits inside the other to form the column. In other words, the smaller one may be nested inside the larger one. A locking device is provided in the reinforcement column. The door may also comprise facing sheets 130a, 130b forming the faces of the door. For example, the a first facing 130a sheet forms the indoor face of the door and a second facing sheet 130b forms the outside face of the door. The facing sheets cover the core sheet 110 and preferably also the door-edge reinforcement column 120, although in embodiments the facing sheets may extend up to, but not cover the door-edge reinforcement column. As shown in figures 3a-3c the facing sheets may be folded to fit around the edges of the door. For example, first facing sheet 130a is folded to form the edges of the door and second facing sheet is folded at its edges but the folded edges fit inside the edges of the first facing sheet. Not shown in figures 3a-3c, the facing sheets may be spaced from the core sheet with bracing ribs between the facing sheets and core sheet. Figure 3c is an enlarged view of the section of the reinforcement column shown in figure 3b. The cross-section is taken where a locking device may be fitted in the door. For example, cross-section may be taken in the plane A shown in figure 3a. As well as the facing sheets 130a and 130b and the U-shape channel section 121 and 123, there are also shown a number of filler plates 125a, 125b and 125c. In the example shown three plates are shown of varying thickness but other numbers of the same or different thicknesses may be used. The space remaining 125d in the reinforcement column 120 may house a lock device. In other words the filler plates 125a-c may be used to fill any space between the lock device and the column such that the lock device is firmly held in the column without gaps to the sides of the column. Since different lock devices may have different thickness, different numbers and thicknesses of filler plates may be used to fill any gap. A further plate 125e may be included on the other side of the lock device. The numbers of plates either side of the locking device may be chosen to set the locking device correctly with respect to the centreline of the door. The locking device may be a deadlocking device such as requiring release by turning of a key or turn-knob, or the locking device may be a latching device such as may be released by turning of a handle. As described, preferably on the inside face of the door the locking device is released by actuation of a push bar or panic bar. The lock device may alternatively be surface mounted instead of being mounted in the column. As shown in figure 3d the core sheet 110 may extend towards the hinged edge of the door. The core sheet is held to a C-shaped section 126 by bracing ribs 132, which we describe later. The core sheet may be sandwiched between bracing ribs. The outer ends of the C-shaped section 126 support the facing sheets 130a, 130b. Other arrangements at the hinged side of the door are possible for coupling or fixing the core sheet to the facing sheets, including further C or U sections and / or L-brackets. Figures 4a to 4g show a sequence of steps of assembly of a security door according to embodiments of the present invention. In figure 4a a first side of the door has largely been assembled, including the core sheet 110, first U-shaped channel 121 of the door-edge reinforcement column 120. Also a first facing sheet such as 130a has been fitted as can be seen because it is folded around the edge of the door. In figure 4a three filler plates 125a-125c are being assembled together. Also shown in figure 4a are two reinforcement plates 128 shown being added to the door-edge reinforcement column. These reinforcement plates arranged across the column to provide strength against deformation or crushing of the column by external force. A number of such plates are spaced along the length of the column from the top of the door to the bottom of the door. For example, as well as the two plates 128 that are shown as ready to be assembled into the door there are already four such plates already assembled into the door and a further two more closely spaced at the bottom end of the column and two at the top of the column (shown covered in figure 3a). Figure 6 shows more detail of the reinforcement plates 128 and filler plates 125a-125c. Reinforcement plates 128 include various tabs that engage in slots or holes in the rectangular door-edge reinforcement column. The plates have a rectangular or H-shape. As shown in figure 6 along one of the longer sides there are three tabs 128-1, 128-2 and 128-3 which respectively fit into holes 120-1, 120-2 and another hole not shown in figure 6. Hole 120-1 and tab 128-1 which are in the middle of the three tabs are longer and the hole 120-1 is a slot. Further tabs 128-4 and 128-5 are formed at the short ends of the plate 128 and drop into slots 120-4 and 120-5 in the reinforcement column 120. The reinforcement plates also include three tabs along the top edge for slotting into holes in the top-part of the door-edge reinforcement column that has yet to be added in figure 4a. The middle tabs along the long top and bottom edges of the plate include parts that extend further than other parts which result in the tab having a stepped shape. The stepped shape is so that the tab sits in holes or slots in different numbers of layers of sheets. For example, looking at the cross-section shown in figure 3c, excluding the filler plates 125-125c, there are three plates or sheets forming the top or bottom of the reinforcement column. The longer part of the central tab may slot through two of the plates and the adjacent slightly shorter parts of the tab may slot into only one of the sheets. In figure 4b the reinforcement plates 128 are fitted in to the column, and the three filler plates are stacked one on top of the other. The top plate 125a of the filler plates has tabs for guiding it to fit into cut-outs in the reinforcement plates. The cut-outs space the middle tab 128-1 from the smaller tabs 128-2 and 128-3 and can also be seen in figure 3c. Also shown in figures 4a and 4b are anti-crush tubes 129. These are shown in more detail in figure 7 which is a cross-section taken through the door-edge reinforcement column and the anti-crush tubes. Almost all of the parts for the door and frame are formed of metal plates such as steel plates that are cut, for example by laser, and then some are folded. The anti-crush tubes 129 may be manufactured by turning, alternatively a sheet plate may be rolled to form the tubes. As shown in figure 7 the tubes 129 fit into holes in opposing faces of the door-edge reinforcement column. For example the tubes may fit into holes in plates 125c and 122. Alternatively, the tubes may fit into holes in the first and second U-shaped channel sections 121 and 123. In either case the tubes are supported in the holes and stopped from falling through the holes by the outer facing sheets at least. In the embodiment shown in figure 7 the tubes are also held by the plates 121 and 123. In the figures four anti-crush tubes are shown with two at a first vertical location and two more at a second vertical location. In other words two anti-crush tubes are arranged side-by-side at two vertical locations. The locking device at a middle vertical location may also provide a third anti-crush region. In embodiments more or less anti-crush tubes 129 may be included. In figure 4c the remaining two reinforcement plates 128 and the filler plates 125a-125c have been added to the assembly. Flat pate 122 is shown as ready to be added to the assembly. Flat plate 122 extends the full length of the door-edge reinforcement column and includes slots into which are received tabs from the reinforcement plates 128. Flat plate 22 is a similar width to U-shaped channel 121 such that when added to the assembly it sits on top of the channel 121 and closes the channel to form a rectangular section. If second U-shape section 123 is included then flat plate 122 does not extend wider than U-shapes channel 121. In figure 4d the flat plate 122 has been assembled into the door-edge reinforcement column. Second U-shaped channel section 123 is ready to be assembled to the door-edge reinforcement column. The section 122 also includes holes or slots for receiving the tabs of the reinforcement plates. As can be seen in the figure, the slots in the section 122 are shorter than those in flat plate 122 because they receive only a smaller part of the tabs of the reinforcement plate 128, as previously discussed. The U-shaped channel section 123 fits over the flat plate and first U-section 121 to complete the door-edge reinforcement section as shown in figure 4e. In figure 4f bracing ribs 132 have been added. In the embodiment shown four bracing ribs 132a-132d are shown but other numbers of bracing ribs may be included. Figure 5 shows the bracing ribs in more detail. Figure 5a is a perspective view of the door showing four bracing ribs in a similar manner to figure 4f. Figures 5b and 5c respectively are enlarged views showing the bracing ribs coupled to the door-edge reinforcement column and the hinged side of the door. Figure 5d is a perspective view showing the rib only away from the door. The bracing ribs are spaced apart vertically over the height of the door. The bracing ribs span across the door from the hinged side (or the side to which the hinges will later be fitted) to the door-edge reinforcement column. The bracing ribs sit against the core sheet and as we will describe below will space apart one of the facing sheets from the core section. In figure 4a a core sheet was shown. Not shown in that figure is that on the underside of the core sheet may be a further facing sheet for the other side of the door that is spaced from the core sheet by a further corresponding series of bracing ribs. Returning to figure 5, the bracing ribs may be formed from a flat sheet and folded to have a top-hat shaped cross-section as shown in figure 5b. The base (or for a hat, the brim) of the top-hat section, identified in the figure by 132-1 and 132-2, may fit flat against the core sheet or may be spaced from the core sheet 110. The base of the top-hat section may be fixed to the core sheet, such as by rivets. At the end of the rib adjacent to the dooredge reinforcement column 120 the rib has tabs for fixing to the column. The ribs are formed from extended parts of the side sections of the top-hat section which are folded transversely to the top-hat section. The tabs may comprise holes to allow the rib to be fixed to the column, such as one or more of the U-shaped channel sections 121, 123, by rivets. At the other end of the bracing rib a similar fixing arrangement may be used. However, in a preferred arrangement, the side faces 132-3 of the top-hat section extend furthest and locate in slots, or are sandwiched in the C-section 126 in the hinged side of the door. Also shown in figure 4f a tube 133 is provided to reinforce the viewing hole or window. This tube 133 is a second anti-crush tube and may be larger than the anti-crush tubes 129 described earlier and included in the door-edge reinforcement column 120. The tube 133 fits through a hole on the core sheet 110 and may held in place by the facing sheets on either side of the door which include holes smaller than the external dimension of the tube and the hole may be approximately the same size as the internal dimension of the tube 133. In figure 4g a facing sheet is added to the assembly and covers the bracing ribs 132, the core sheet 110 and the column 120. The facing sheet may be spaced from the core sheet by the ribs and the top (or crown) of the ribs may touch the facing sheet. Alternatively, the facing sheet may spaced from the bracing ribs. We previously described that the door set may include a door frame, as shown in figures 1 and 2. Figures 8 to 10 show detailed features of the door frame 200 according to the present invention. To achieve high security the doors are generally supplied as a door set including the door leaf and a door frame. This means the door is a good fit in the frame and can meet security, safety and fire requirements more reproducibly. The door frame includes first and second anti-crush side jambs 201 and 202. The side jambs may also be known as legs. The side jambs form the side parts of the door frame into which the door closes. The side jambs may be joined together across the top of the door by a header jamb 203. Optionally, a door threshold or footer may be included to complete the frame surrounding the door. However, the door threshold or footer is commonly omitted as it is difficult to fit and may be a trip-hazard. Hence, the door frame commonly comprises the first and second side jambs 201,202, and the header jamb 203. Figures 8a and 8b show cross-sections through the anti-crush side jambs or legs. The cross-section may be used for the first and second side jambs 201,202 and also the header jamb 203. The cross-sections comprise an outer sheet layer 210 which forms the outer part of the jamb. The outer sheet layer preferably meets a fixing plate 212. One or more fixing plates may be spaced along the height of the side jambs and used for fixing the door frame into an opening such as an opening in a wall. The outer sheet layer may have a number of folds or bends to form it into an L-shape, in combination with the fixing plate. That is, the side edges of the outer sheet layer meet the fixing plate and together form an L-shape. For example, when fixed to a wall the side jamb has a first thickness and a second thickness from an outer face to the fixing plate. The first thickness T1 forms the jamb, which is the frame into which a door closes. The second thickness T2 includes the first thickness T1 but is thicker to include a stop against which the door closes. Hence, the outer sheet may have six folds to form the doorjamb including stop. As previously mentioned, the side jambs are anti-crush, that is they are strengthened with internal features to prevent or significantly reduce the likelihood of being crush by force. A first frame U-shaped channel section 214 is provided that extends along substantially the full length of the side jamb of the door frame. The U-shaped channel is formed of a flat sheet such as a steel sheet, with two folds or bends. The edges of the U-channel locate in apertures in the fixing plate. The first frame U-channel is located in the thinner part of the side jamb without the stop. One side of the U-channel may be arranged close to the side of the jamb and the other may be arranged close to the centre of the jamb, namely close to the region where the thickness increases to include the stop of the door frame. By including the side 214a of the U-channel close to the middle of doorjamb region it provides extra strength against crushing the doorjamb. A second frame U-shaped channel 216 is provided that is larger than the first 214. The second U-channel is close to the full width of the door frame or doorjamb and again has edges that locate in apertures in the fixing plate. The first U-channel 214 is nested in the second U-channel, that is the first U-channel sits inside the second U-channel 216, and both have their sides against the fixing plate. The second U-channel sits inside, and against the inside of the doorjamb part of the frame, with the first U-channel inside the second U-channel. An optional third U-channel 218 may be provided which sits with its edges against the outside of the second U-channel and support and strengthens the stop of the door frame, that is, the thicker portion of the door frame. The outer sheet layer wraps around the three stacked U-channels. The third U-channel may only be used in some places up the height of the jamb and / or may be included in only one of the jambs such at the non-hinged or opening side. Figure 8b shows another cross-section of the side jamb of the door frame. Whereas the jamb shown in figure 8a may be that of the non-hinged side, that shown in figure 8a may be the hinged side. The cross-section shown in figure 8b includes wind-out fixings 220. The wind-out fixing are threaded units which are located in threaded holes in the fixing plate 212. The wind-out fixings may be screwed or rotated to move inwards or outwards. When in an aperture in a wall, the wind-out fixings may be wound outwards or inwards to push against the wall. This may used to adjust the fitting of the frame in the aperture, for example, to set the frame square or to take account of unevenness at the edges of the aperture. The wind-out fixing have a head configured to receive a hexagonal key or socket to wind the fixing in or out. The wind-out fixing further comprises a central through-bore 221. The through-bore 221 is configured to receive a fixing such as a screw or bolt for fixing the frame to the wall opening. Also shown in figure 8b is that the outer sheet layer and U-channels may include holes 222 through which fixings and tools can be inserted for adjusting the wind-out fixings and fixings can be inserted. Also as shown in figure 8b, two wind-out fixings may be arranged adjacent to each at a vertical position on a jamb. Although it will depend on the height of the door, as shown in figure 1, pairs of wind-out fixings may be located at six vertical positions on each jamb. Other numbers of positions are also possible. Figure 8b shows a plate 230 inside the first U-shaped channel 214. This plate is for mounting a hinge and will be described with reference to figures 9a-9c. Figure 9a shows a hinge 300 fixed to a door. Figure 9b shows a hinge 300 fixed to the door frame. Figure 9c is a cross-section view through the frame and door at a hinge location. In figure 9c the outer sheet layer forming the leg or jamb and stop of the door frame can be seen. The wind-out fixings and the plate 230 to which a hinge is fixed can also be seen. Part of the door 100 is also shown with facing sheet 130. The door is closed against the doorjamb and stop. As shown in figures 9a and 9b the hinge may be fixed to the door and frame by usings fixings (not shown) in holes in the hinges, for example, bolts or rivets. Hinges may include a pin or stud 310 on the back faces of the plates of the hinge. The pin or stud 310 fits into a respective hole in the door edge or frame and helps to align the door to the frame. The studs also aid security and strength by being larger than fixings and provide additional support should an attacker try to remove the hinge. The stud helps to hold the hinge in position and prevent its removal. In a similar manner, hinge bolts 240 may be provided. As shown in figure 9a a hinge bolt may be fixed to, or into, the edge of the door with a more substantial bolt shaped stud or pillar. In figure 9b the hinge bolt is shown inserted into a hole in the frame, but the door is not shown so the part fixed into the door is shown. The part fixed into the door may be a narrower diameter than the part of the hinge bolt that protrudes from the door. Two hinge bolts may be provided at each hinge, with one above and one below the hinge. Since the frame may be strengthened in the region of the hinge, for example, to accommodate fixings, the hinge bolt also benefit by being located in this strengthened region. As shown in figures 9a and 9c the ends of the studs of the hinge bolts may be rounded or chamfered to allow the hinge bolt 240 to easily slot into a respective hole as the door is rotated closed. In figure 9c the hinge bolt can be seen extended from the door, through the hinge, and into the plate 230 of the frame of the door. The core sheet of the door may include cutouts to accommodate the mounting of the hinge bolt 240. Hinge bolts provide added security to the hinged side of a door in the same way that the opening side of a door may be secured by bolts. We have described the structure, mounting and security and strengthening aspects of the legs or jambs of the door frame. The header beam of the door frame may be similarly formed, such as including strengthening U-shaped sections, and with wind-out fixings etc. Figure 10 is a perspective view of how the header jamb is fixed to a leg or side jamb of the door frame. The header jamb 203 may include tabs 250 that extend into slots in the side jamb. For example, the tabs may extend from the outer sheet layer of the header beam and fit through slots in the outer sheet layer, and first and second U-channel sections of the side jamb. A similar tab 252 may also fit through a slot in the stop of the door frame. Once slotted through and into the frame, the tabs 250 and 252 may be bent over to hold the frame together. Preferably, the tabs and side jamb of the frame include holes that align when the tabs are folded over. The tabs may then be fixed in the folded position by riveting the tabs folded over against the side jamb of the frame. Alternatively, the side jambs may include tabs and the header jamb may include slots into which the tabs are received. Figures 11 and 12 are flow charts of methods of manufacturing a security door and a door frame for a security door set. In figure 11 the method of manufacturing a security door comprises at step 410 assembling a core sheet such as sheet 110 to the first U-channel section such as section 121. At step 420 a locking device is mounted in the U-channel section. At step 430 a second U-shaped channel section, such as 123, is assembled opposing the first U-shaped channel section to form a door-edge reinforcement column 120 with the lock device mounted therein. At step 440 bracing ribs such as lateral bracing ribs 132 may be mounted across the door, for example, across core sheet 110. At step 450 at least one facing sheet may be fixed to the door assembly to cover the core sheet and bracing ribs, and optionally the door-edge reinforcing column. A second facing sheet may be attached to the other side of the door. This step may be performed around the same time as the first facing sheet is attached, or around the time of one of the first steps when the core sheet is fixed to the first U-channel. The method may further comprise arranging reinforcement plates 128 into slots across the door-edge reinforcement column to support the four sides of the column. The step of mounting the lock device into the first U-shaped channel section may comprise mounting the lock device with one or more filler plates 125 to fill a space in the column between the lock device and the first and second U-shaped channel sections. Other aspects described in relation to figures 1 to 7 may also be included in the method of manufacturing the door. In figure 12 the method of manufacturing a security door frame comprises, at step 510, forming each of the first and second doorjambs by nesting a first frame U-shaped channel section inside a second larger frame U-shaped channel section. The U-shaped channels are then, at step 520, positioned inside an L-shaped outer layer. At step 530 a fixing plate such as 212 is inserted and at step 540 the first frame U-shaped channel section is aligned such that a side wall is aligned approximately to a middle upright line of the door jamb. At step 550 a header beam or jamb is fixed across the tops of the first and second door jambs to form the security door frame. In manufacturing the door and frame, most of the parts may be formed by cutting a metal sheet such as a steel sheet. For example, laser cutting such a sheet. Some parts when cut may require folding or bending to produce their required three-dimensional shape. Hence, the parts for producing a security door and frame may be manufactured at a facility that has laser cutting machinery. Since such facilities are widespread across the globe, instead of manufacturing the door set and shipping around the world, it is expected 5 to be more efficient to manufacture and assemble locally. Specifically, the door set has been designed with the ease of manufacture and assembly in mind. The person skilled in the art will readily appreciate that various modifications and alterations may be made to the above described door set. The modifications may be made 10 without departing from the scope of the appended claims. For example, the numbers and arrangement of features may be changed. Furthermore, variations in the actual shapes of the parts may be made without diverging from the general scope of the present invention. 15

Claims

1. A security door, comprising:a core sheet;a door edge reinforcement column formed of a first channel section and a second opposing section, the first section and second section together forming the door-edge reinforcement column at a locking edge of the door; andat least one facing sheet covering the core sheet, wherein bracing ribs are configured between the at least one facing sheet and the core sheet.

2. The door of claim 1, wherein the first channel section and / or second opposing section have U-shaped cross-sections, arranged opposing each other so as to form the column with a space therein for receiving the lock device.

3. The door of claim 1 or claim 2, wherein the at least one facing sheet comprises a first facing sheet covering a first side of the core sheet and spaced from the core sheet by said bracing ribs and a second facing sheet covering a second side of the core sheet, opposite to the first side, with further bracing ribs between the core sheet and second facing sheet.

4. The door of any of claims 1 to 3, wherein the bracing ribs have a top-hat shaped cross-section.

5. The door of claim 4, wherein the top-hat shaped cross-section has a base resting against the core sheet.

6. The door of any preceding claim, wherein the bracing ribs comprise tabs at a first end which are fixed to the door-edge reinforcement column.

7. The door of any preceding claim, wherein the door-edge reinforcement column has a substantially rectangular cross-section formed by the first channel section and second opposing section.

8. The door of claim 7, further comprising reinforcement plates spaced along the length of the column, the reinforcement plates arranged crossing the column supporting the four sides of the column against crushing.

9. The door of claim 8, wherein the reinforcement plates comprise tabs engaging in holes or slots in each of the four sides of the rectangular column.

10. The door of any preceding claim, wherein the door-edge reinforcement column comprises first anti-crush tubes spacing apart faces of the first channel section and the second opposing section.

11. The door of any preceding claim, further comprising a viewing hole or window through the core reinforcing sheet and at least one facing sheet, the viewing hole or window supported by a second anti-crush tube.

12. The door of any preceding claim, further comprising:hinges fixed to the door at an opposing edge to the door edge reinforcing column; andhinge bolts fixed into the opposing edge and extending from the door for locating into corresponding holes in the frame for securing the opposing edge of the door to the frame when the door is closed.

13. The door of claim 12, further comprising a hinged edge reinforcement having a C-shaped cross-section and through which hinge fixings and the hinge bolts are located.

14. The door of any preceding claim, wherein the C-sections and / or bracing ribs are formed by folding or bending flat metal sheet.

15. The door of any preceding claim, wherein any of the bracing ribs, core sheet, first channel section, second opposing section and / or at least one facing sheet are fixed together by rivets.

16. A security door frame, comprising first and second side jambs joined by a header jamb to form the security door frame, the first and second side jambs each comprising:one or more fixing plates for receiving fixings for mounting the frame;an outer sheet layer having longitudinal bends or folds, the outer sheet layer and one or more fixing plates forming an outer shape of the side jamb for receiving a door;a first frame section and a larger second frame section, the first and second frame sections having channels along their lengths and the first frame section is nested in the second frame section, the first and second frame sections positioned within the outer sheet layer with edges meeting the one or more fixing plates; andwherein a side wall of the first frame section is arranged along an approximate middle upright line of the frame to support the side jamb.

17. The security door frame of claim 16, wherein the outer sheet layer and one or more fixing plates form an L-shaped outer cross-section that forms the door jamb and stop of the door frame, the first and second frame section arranged in the jamb part of the door frame.

18. The security door frame of claim 17, wherein the side wall of the first frame channel section is aligned approximately to the inner edge of the stop of the frame.

19. The security door frame of claim 17 or claim 18, further comprising a third channel section arranged in the stop of the frame with a side wall of the third channel section aligned approximately with the middle upright line of the frame.

20. The security door frame of any of claims 16 to 19, further comprising hinges fixed to one of the side jambs, wherein the outer sheet layer, first frame section and second frame section comprise aligned holes for receiving a hinge bolt for securing an edge of a door to the side jamb when the door is closed.

21. The security door frame of any of claims 16 to 20, wherein any one or more of: the first side jamb, second side jamb and header jamb, comprise wind-out fixings for adjusting the alignment of the door frame in a doorway.

22. The security door frame of any of claims 16 to 21, wherein the first side jamb and second side jamb comprise first fixing members and the header jamb comprises second fixing members, andthe first fixing members comprise slots or holes and the second fixing members comprise tabs slotted in to the slots or holes and bent over to secure one of the side jambs to the header jamb, orthe first fixing members comprise tabs and the second fixing members comprise slots or holes, and the tabs are slotted in to the slots or holes and bent over to secure one of the side jambs to the header jamb.

23. The security door frame of claim 22 wherein the folded tabs are riveted to one of the side jambs or header jamb.

24. The security door frame of any of claims 16 to 22, wherein the fixing plates comprise cut-outs into which are located the edges of the first frame channel section and second frame channel section.

25. A security door set comprising the door of any of claims 1 to 15 and the frame of any of claims 16 to 24.

26. A method of manufacturing a security door, comprising: assembling a core sheet to a first channel section; mounting a lock device in the first channel section;assembling a second section opposing the first channel section to form a door-edge reinforcement column;fitting one or more bracing ribs across the core sheet; andassembling at least one facing sheet covering the core sheet and the one or more bracing ribs.

27. The method of claim 26, comprising assembling the at least one facing sheet covering the core sheet, the one or more bracing ribs and the door-edge reinforcement column.

28. The method of claim 26 or 27, wherein the at least one facing sheet comprises a first facing sheet covering a first side of the door and further comprising assembling a second facing sheet to the door, the second facing sheet covering a second side of the door.

29. The method of any of claims 26 to 28, further comprising arranging reinforcement plates into slots across the door-edge reinforcement column to support the four sides of the column.

30. A method of manufacturing a security door frame comprising first and second door jambs joined by a header beam, the method comprising:forming each of the first and second door jambs by:nesting a first frame channel section inside a second larger frame channel section;positioning the nested first and second frame channel sections inside an outer sheet layer, the outer sheet layer comprising an elongate sheet bent to form the outer shape of the jamb;inserting one or more fixing plates into the outer sheet layer; andaligning a side wall of the first frame channel section to an approximatemiddle upright line of the jamb; andfixing the header beam across the tops of the first and second door jambs to form the security door frame.

31. The method of any of claims 26 to 30, wherein the first and second frame sections are U-shaped channel sections formed by cutting a metal sheet and folding to form the U-shaped channel sections.

32. A kit of parts for manufacturing a security door, the kit of parts comprising: a core sheet;a first channel section and a second section configured for forming a door-edge reinforcement column for a locking edge of the door;at least one facing sheet for covering the core sheet; andbracing ribs configured for mounting between the at least one facing sheet and the core sheet.

33. A kit of parts for manufacturing a side jamb or header jamb for a security door frame, the kit of parts comprising:one or more fixing plates for receiving fixings for mounting the frame;an outer sheet layer having longitudinal bends or folds, the outer sheet layer and one or more fixing plates configured to form an outer shape of the side jamb or header jamb for receiving a door;a first frame section and a larger second frame section, the first and second frame sections having channels along their lengths and the first frame section sized to be nestedin the second frame section, the first and second frame sections sized to be positioned within the outer sheet layer and having edges configured to mount into the one or more fixing plate.