GB2502809A

GB2502809A - Letter plate constructions

Info

Publication number: GB2502809A
Application number: GB201210080A
Authority: GB
Inventors: Stuart Carpenter; Clement George Whittle
Original assignee: Assa Abloy Ltd
Current assignee: Assa Abloy Ltd
Priority date: 2012-06-07
Filing date: 2012-06-07
Publication date: 2013-12-11
Also published as: GB201210080D0

Abstract

A letter flap assembly comprises a frame 6B and a flap 8B. The flap may be connected to a pair of end caps 9B, with the end caps each being connected to the frame by inter-engagable formations. The flap is preferably biased in the closed position by one or more elastomeric torsion rods or the like members 11B, 12B. The torsion rods may have non-uniform cross sections and may be fabricated from acetal homopolymer resin. The flap and end caps may be adapted so as to be connectable to one another without the use of fasteners and capable of being repeatedly assembled and disassembled

Description

Letter plate assemblies This invention relates to letter plate assemblies and to letter flap assemblies for letter plates. Such letter flap assemblies may be formed as integral parts of letter plate assemblies.

Tt is very well known to provide letter plate assemblies which include pivotally mounted flaps that are pivotable between closed and open positions and that, when in their closed positions, cover over the opening through which post may pass through the letter plates.

The pivotal mounting of flaps on letter plate assemblies can be achieved in a variety of ways.

Desirably, however, the assembly is straightforward and easily accomplished. It is also desirable that the assembly is robust but able to be dissembled and reassembled to allow late configuration and reconfiguration of stock. Existing letter plate assemblies have various shortcomings in those respects It is an object of the invention to provide a letter flap assembly that offers an improvement in one or more respects over existing designs.

It is a further object of the invention to provide a letter plate assembly that incorporates a letter flap assembly and offers an improvement in one or more respects over existing designs.

According to a first aspect of the invention there is provided a letter flap assembly comprising a frame, a letter flap and a pair of end caps, the end caps and frame having interengageable formations by which the end caps engage opposite ends of the frame, the letter flap being pivotally mounted at its cpposite ends on the end caps.

By providing end caps with interengageable formations for engaging opposite ends of the frame, assembly of the letter flap assembly can be facilitated and the need for any special machinery avoided. The assembly can be arranged so that upon assembly of the end caps on the frame the letter flap is retained on the end caps. Also the modular nature of the assembly allows the same end caps to be used with letter flaps of different lengths, reducing the number of parts that are required to make a range of letter plates of different sizes and reducing costs.

Preferably the end caps and the opposite ends of the frame are push-fitted together. Preferably the push-fitting can be carried out by hand. By providing an appropriate interference fit, the end caps and the frame can be pressed together by hand but are then held together reasonably securely. Thus, the frame, the pair of end caps and the letter flap are preferably able to be assembled together into an operational state without any auxiliary fasteners. More preferably the frame, the pair of end caps and the letter flap are able to be dissembled and re-assembled repeatedly. Such arrangements greatly facilitate assembly and re-assembly of the letter flap assembly allowing reconfiguration of stock with a low number of parts.

Preferably each end cap is of one-piece construction.

This further reduces the number of parts and facilitates assembly.

Preferably, the assembly further includes screw threaded fasteners, for example, screws, for securing the end caps to the frame and thereby securing the pivotal mounting of the letter flap on the end caps. Such screws are preferably not required for the parts to be held together but do provide an extra level of security to the fastening.

The end caps preferably have male formations engaging female formations at opposite ends of the frame. An arrangement of this kind can be made especially economically. In an embodiment of the invention described below, the frame is an integral part of a letter plate assembly and the male formations on the end caps are received in female formations formed by the combination of a frame member and a box-shaped sleeve on one end of which it is slidably engaged. Thus the box-shaped sleeve and the frame member together define the frame.

Preferably, the frame member is an extrusion.

Opposite ends of one or more channels in the frame may define all or some of the female formations. After the frame member is extruded, openings or other formations may be created in the frame member. It should be understood, however, that it is within the scope of the invention for the letter flap assembly to be formed as a sub-assembly separate from the box-shaped sleeve. In that case the frame may be defined solely by the frame member which may itself have female portions engageable by the end caps.

Also, it may be noted that the box-shaped shape of the sleeve is not relevant to the creation of the female fornations in which the male formations on the end caps engage and it is therefore possible for the box-shaped sleeve to take the form of a plate-like member or some other shape for the purpose of defining portions for interengaging with the end caps.

The end caps may be of cast metal, for example cast steel; alternatively they may be moulcied, for example they may be injection moulded from plastics material.

The frame is preferably of generally elongate rectangular shape. Interengaging formations of the end caps and the frame are preferably provided at both upper and lower regions of the opposite ends of the frame. In an embodiment of the invention described below with reference to the drawings the interengaging formations on the end caps and the frame extend between the upper and lower regions of the frame.

The letter flap Is preferably pivotable between a closed position and an open position, the flap being resiliently biased into the closed position.

It is within the scope of the first aspect of the invention for the resilient bias to be provided in any of a variety cf ways which may include the use of compression or tension springs. In an especially preferred embodiment of the first aspect of the invention, the resilient bias is preferably provided by torsion in each of one or more elongate members, which are preferably elastomeric members, the torsion being about a longitudinal axis of each of the one or more elongate members. By using such a member, which is preferably elastomeric, to provide the resilient bias, it becomes possible to provide an assembly of especially simple construction and with few parts.

It is within the scope of the invention for there to be a single elastomeric member, conveniently disposed at one end of the letter flap; in that case a plain pivotal mounting of the letter flap may be provided at its other end. More preferably, however, two elastomerio members are provided, one in the region of each end of the letter flap.

Each of the one or more elastomeric members is preferably of generally round cross-section, the cross-section varying along the length of the member. By appropriate selection of the variation in cross-section, any tendency of the member to twist or squirm in situ may be reduced. Preferably, the variation in cross-section is gradual. Each of the one or more elastomeric members preferably has a pair of waisted portions between a mid portion and the opposite ends of the elastomerio member.

The one or more elastomeric members are preferably made of a polymer material, more preferably an acetal resin. The material is preferably a homopolymer.

Each of the one or more elastomeric members preferably engages an end cap and the letter flap. Where two elastomeric members are provided, one may be provided in engagement with one end cap and one end of the letter flap and the other may be provided in engagement with the other end cap and the other end of the letter flap.

Each of the one or more elastomeric members is preferably received in a channel formed in the letter flap.

Preferably, each of the one or more elastomeric members is non-rotatably mounted at one end region in an end cap and non-rotatably mounted at an opposite end region in the letter flap. The end regions of each of the one or more elastomeric members are preferably provided with laterally projecting formations for facilitating the non-rotatable engagement. The channel is preferably open on one side. The open side may accommodate a laterally projecting formation on an elastomeric member.

As already indicated the use of one or more elastomeric members in which torsion provides the resilient bias is a special feature of the invention and may be employed without adopting all the features of the first aspect of the invention. Thus, according to a second aspect of the invention there is provided a letter flap assembly comprising a frame, a letter flap pivotable between a closed position and an open position, the flap being resiliently biased into the closed position, the resilient bias being provided by torsion in each of one or more elongate elastomeric members, the torsion being about a longitudinal axis of each of the one or more elongate elastomeric members.

As previously indicated, by using such an elastomeric member to provide the resilient bias, it becomes possible to provide an assembly of especially simple construction and with few parts.

Each of the one or more elastomeric members is preferably of generally round cross-section, the cross-section varying along the length of the member. By appropriate selection of the variation in cross-section, any tendency of the member to twist or squirm in situ may be reduced. Preferably, the variation in cross-section is gradual. Each of the one or more elastomeric members preferably has a pair of waisted portions between a mid portion and the opposite ends of the elastomeric member.

Each of the one or more elastomeric members is preferably received in a channel fcrmed in the letter flap.

Preferably, each of the one or more elastomeric members is non-rotatably mounted at one end region in the frame and non-rotatably mounted at an opposite end region in the letter flap. In accordance with the second aspect of the invention, the mounting in the frame may be a direct mounting in the frame or a mounting in another member, for example, an end cap, fitted to the frame. The end regions of each of the one or more elastomeric members are preferably provided with laterally projecting formations for facilitating the non-rotatable engagement. The channel is preferably open on one side. The open side may accommodate a laterally projecting formation on an elastomeric member.

Other features described above in respect of the first aspect of the invention may also be incorporated in this second aspect of the invention and are not repeated again here.

As already indicated, the ability of the letter flap assembly to be assembled into an operational state without any auxiliary fasteners (and preferably dissembled and re-assembled repeatedly) is a special feature of the invention and may be employed without adopting all the features of the first aspect of the inventicn. Thus, according to a third aspect of the invention there is provided a letter flap assembly comprising a frame, a letter flap and a pair of end caps, the letter flap being pivotally mounted at its opposite ends on the end oaps, the frame, the pair of end caps and the letter flap being able to be assembled together into an operational state without any auxiliary fasteners. The assembly according to the third aspect of the invention is preferably able to be dissembled and re-assembled repeatedly.

Such arrangements greatly facilitate assembly, and, in the preferred embodiment, re-assembly of the letter flap as s e mb 1 y.

Preferably, the end caps and the opposite ends of the frame are push-fitted together. The end caps preferably have male formations engaging female formations at opposite ends of the frame. n arrangement of this kind can be made especially economically.

Other features described above in respect of the first and/or second aspect of the invention may also be -10 -incorporated in this third aspect of the invention and are not repeated again here.

A letter flap assembly according to any aspect of the invention may be incorporated in a letter plate assembly, either as an additional free-standing assembly fixed in place or as an integrated single assembly as in an embodiment of the invention described below. Thus the letter flap assembly in any of the forms described above may be a letter plate assembly. Also, the present invention further provides a letter plate assembly comprising a letter flap assembly as defined above. The letter flap assembly may be provided on an interior side or an exterior side of the letter plate assembly.

The letter plate assembly may include a further letter flap assembly as defined above, the letter flap assemblies being able to be provided on opposite sides of a door.

The letter plate assembly may further include a box-shaped housing for forming a sleeve in a door. A pair of telescopically engaging housings may be provided, one on the interior face of a door extending into the interior of the door and another on the exterior face of a door extending into the interior of the door. Such housings are of particular value with hollow doors.

r7hilst various aspects of the invention have been described above, it should be understood that, as already implied, features described in one context may also be provided in another context, even when that is not -11 -explicitly stated.

By way of example an embodiment of the invention will now be described with reference to the accompanying schematic drawings, of which: Fig. 1 is an exploded isometric view of a letter plate assembly; Fig. 27 is an exploded isometric view of parts of the assembly of Fig. 1 illustrating a first stage of assembly; Fig. 2B is an isometric view of the parts of Fig. 2A after the first stage of assembly; Fig. 3 is an isometric view of the parts shown in Figs. 2A and 2B, and other parts of the assembly shown in Fig. 1, illustrating a second stage of assembly, Fig. 4 is a front view of the parts shown in Fig. 3, illustrating a third stage of assembly, Fig. 5 is an isometric view of one end of the assembly including the parts shown in Fig. 4 and illustrating a fourth stage of assembly, and Fig. 6 is an isometric view of one end of the assembly including the parts shown in Fig. 5 and showing the complete assembly.

The letter plate assembly shown in Fig.l is in many respects of conventional design. The assembly comprises: an interior box-shaped sleeve 1 which is also referred to herein as a "housing"; a seal 2 associated with the box- -12 -shaped sleeve 1; an exterior box-shaped sleeve 3; a seal 4 associated with the exterior box-shaped sleeve 3; a draught exoluder 5; an interior letter flap assembly generally comprising a frame 6A (with a liner 7A around an opening in the frame 6A) and a letter flap GA; and an exterior letter flap assembly generally comprising a frame GB (with a liner 7B around an opening in the frame 6B) and a letter flap 8B.

A pair of screws 25 are also provided for holding the assembly together, for example on opposite sides of a door, with the seals 2 and 4 on opposites faces of the door.

In the letter plate assembly described in outline above, it is the letter flap assemblies that are of novel desIgn and that will now be particularly described in further detail below. !Jjhe exterior letter flap assembly will be described but it should be understood that the structure of the interior letter flap assembly is substantially the same.

The exterior letter flap assembly comprises the sleeve 3, the frame 6B (with liner 7B), the letter flap GB, a pair of end caps 9B and lOB, elastomeric members 11B and 12B and finally two pairs of screws 13B. The structure of the letter flap assembly and the way in which the parts fit together is most easily described by explaining the way in which they are assembled.

Referring now to Figs. 2A and 2B, the end cap GB is shown together with elastomeric member 11B. The elastomeric member fiB is elongate and of circular cross- -13 - section except at one end, but the diameter of the cross-section varies along the length of the member defining waisted portions 11W on either side of the mid portion cf the member. The end cap 9B has, towards one of its ends, a prcjeoting post 14 which is of circular cross-section along most of its length but has an end portion 15 of semi-circular cross-section at its distal end, with a rectangular aperture 16 formed in the portion 15. Said one end of the elastomeric member 118 is of semi-circular cross-section and carries a laterally projecting lug 17 which can be inserted into the aperture 16, as shown in Fig. 28, thereby connecting said one end of the elastomeric member non-rotatably to the end cap 98. In Figs. 2A and 28 another laterally projecting lug 18 is shown projecting upwardly from the opposite end of the elastomeric member but it should be understood that these drawings are showing the member llBwith about 180 degree torsional strain along its length.

Referring now to Fig. 3, which shows the elastomeric member 11B, and the elastomeric member 128, in their natural positions, the end cap 98 is shown rotated through degrees about the axis of the elastomeric member 118 with the member liB about to be inserted into one end of a channel 19 in the letter flap 88 and the other elastorneric member l2B fitted to the end cap 108 (in the same way as the elastomeric member 118 is fitted to the end cap 9B) about to be inserted into the opposite end of the channel -14 - 19. The end caps 9B and lOB are shown in juxtaposition to the remainder of the letter plate assembly. It should be noted that the lugs 18 of the elastomeric members llB and 12B project upwardly so that in their natural positions so that no torsional strain is introduced into the elastomeric members. Fig. 4 is similar to Fig. 3 but shows as a front view the end caps 9B and lOB with elastomeric members IIB and 12B partly fitted into the ends of the channel 19. As oan be seen most clearly in Fig. 3, the channel 19 is open along its top edge defining a slot 20 in which the lugs 18 are reoeived, thereby coupling the elastomerio members lAB and 12B non-rotatably to the letter flap 8B. The ends of the lugs 18 are just visible in Fig. 4. As will be appreciated, with the parts in the positions shown in Fig. 4, there is little torsional stress in the elastomerio members 11B and 12B.

Fig. 5 shows the end cap 9B about to be push-fitted into the end of the frame GB. The frame GB is slidably engaged with the sleeve 3, holding those parts together with the frame member GB spaced from the sleeve 3. The end oap 9B and the letter flap 8B are shown rotated around about 180 degrees from the position shown in Fig. 4, so the torsional stress in the elastomerio members liE and 12B is still very small. The arrangement is suoh that with the flap 8B in a fully closed position there is just a small torsional strain of a few degrees along the length of the each of the members liB and 12B. The end cap 9B has a male -15 -formation 21 which is engageable in the corresponding female formation 22 formed by the frame member 6B including channels 22A. The end cap 9B is a push-fit (interference fit) by hand and therefore is held in place when fully inserted as shown in Fig. 6. It will be understocd that the end cap lOB is fitted into the opposite end of the frame 6B in substantially the same way.

In order to make the fitting of the end caps into the frame very secure the screws l3B are fixed in place, engaging holes 23 in the frame 6B and holes 24 in the end caps 9B and lOB. It may be noted that in Fig. 6, the letter flap is shown as a transparent member so that the frame 6B (and the elastomeric member 11B) is visible.

Once the letter flap assembly is fully assembled as shown in Fig. 6 it can be inserted into a door from one side and fastened to the other letter flap assembly inserted from the other side of the door by the screws 25 engaging in holes 26 (Fig. 5) in the end caps.

As will now be understood, the elastomeric members llB and 12B mount the letter flap OB for pivotal movement about the longitudinal axis of the members and also bias the flap resiliently into the closed position shown in Fig. 5. The flap 8B can be pivoted from that position about the axis of the elastomeric members, in an anti-clockwise direction as seen in Fig. 5, to an open position; that pivoting movement causes the elastomeric members llB and 12B to suffer -16 -addItional torsion strain and stress and is therefore resiliently resisted.

The elastomeric members 118 and 128 are in this partioular example made of a medium viscosity aoetal homopolymer resin, such as that sold under the trade mark Delrin® 5000L by E.I. du Pont de Nemours and Company.

Tt will be understood that the construction of the interior letter flap assembly is substantially the same as that of the exterior letter flap assembly. In Fig.l parts of the interior letter assembly are identified by the same reference numeral as the exterior letter flap assembly but with the suffix A. As should now be understood, the letter flap assemblies are able to be assembled by simple push fitting by hand of just a few parts and the assemblies can be disassembled and reassembled as desired, for example to allow late configuration or reconfiguration of stock.

While one particular example of letter plate assembly has been described, it should be understood that many modIfications may be made to the assembly. For example the assembly shown in the drawings is suitable for use in a UPVC door where the telescopically engaging sleeves 1 and 3 are of particular value. In a solid door, those sleeves may be replaced by, for example, flat plates.

Claims

-17 -Claims: 1. A letter flap assembly comprising a frame, a letter flap and a pair of end caps, the end caps and frame having interengageable formations by which the end caps engage opposite ends of the frame, the letter flap being pivotally mounted at its opposite ends on the end caps.
2. An assembly according to claim 1, in which the end caps and the opposite ends of the frame are push-fitted together.
3. An assembly according to claim 1 or 2, in which the frame, the pair of end caps and the letter flap are able to be assembled together into an operational state without any auxiliary fasteners and can be dissembled and re-assembled repeatedly.
4. An assembly according to claim 3, further including screw threaded fasteners for securing the end caps to the frame and thereby securing the pivotal mounting of the letter flap on the end caps.
5. An assembly according to any preceding claim, in which the end caps have male formations engaging female formations at opposite ends of the frame.
6. An assembly according to claim 5, in which opposite ends of one or more channels in the frame define all or some of the female formations.
7. An assembly according to any preceding claim, in which the end caps are each of one-piece construction.

-18 -
8. An assembly according to any preceding claim, in which the frame is of generally elongate rectangular shape and interengaging formations of the end caps and the frame extend between upper and lower regions of the opposite ends of the frame.
9. An assembly according to any preceding claim, in which the letter flap is pivotable between a closed position and an open position, the flap being resiliently biased into the closed position.
10. An assembly according to claim 9, in which the resilient bias is provided by torsion in each of one or more elongate elastomeric members, the torsion being about a longitudinal axis of each of the one or more elongate elastomeric members.
11. An assembly according to claim 10, in which each of the one or more elastomeric members is of generally round cross-section, the cross-section varying along the length of the member.
12. An assembly according to claim 11, in which the variation in cross-section is gradual.
13. An assembly according to claim 11 or 12, in which each of the one or more elastomeric members has a pair of waisted portions between a mid portion and the opposite ends of the elastomerio member.
14. An assembly according to any of claims 10 to 13, in which the one or more elastomerio members are made of an acetal homopolymer resin.

-19 -
15. An assembly according to any of claims 10 to 14, fri which each of the one or more elastomeric members engages an end cap and the letter flap.
16. An assembly according to claim 15, in which each of the one or more elastomeric members is received in a channel formed in the letter flap.
17. An assembly according to claim 15 or 16, in which each of the one or more elastomeric members is non-rotatably mounted at one end region in an end cap and ncn-rotatably mounted at an opposite end region in the letter flap.
18. An assembly according to claim 17, in which the end regions of each of the one or more elastomeric members are provided with laterally projecting formations for facilitating the non-rotatable engagement.
19. An assembly according to claim 18, in which the channel is open on one side.
20. A letter flap assembly substantially as herein described with reference to the accompanying drawings.
21. A letter flap assembly comprising a frame, a letter flap pivotable between a closed position and an open position, the flap being resiliently biased into the closed position, the resilient bias being provided by torsion in each of one or more elongate elastomeric members, the torsion being about a longitudinal axis of each of the one or more elongate elastomeric members.
22. An assembly according to claim 21, in which each of the one or more elastomeric members is of generally round -20 -cross-section, the cross-section varying along the length of the member.
23. An assembly according to claim 22, in which the variation in cross-section is gradual.
24. An assembly according to claim 22 or 23, in which each of the one or more elastomeric members has a pair of waisted portions between a mid portion and the opposite ends of the elastomeric member.
25. An assembly according to any of claims 21 to 24, in which the one or more elastomeric members are made of an aoetal homopolymer resin.
26. An assembly according to any of claims 21 to 25, in which each of the one or more elastomeric members is received in a channel formed in the letter flap.
27. An assembly according to claim 26, in which each of the one or more elastomeric members is non-rotatably mounted at one end region in the frame and non-rotatably mounted at an opposite end region in the letter flap.
28. An assembly according to claim 27, in which the end regions of each of the one or more elastomeric members are provided with laterally projecting formations for facilitating the non-rotatable engagement.
29. An assembly according to claim 28, in which the channel is open on one side.
30. A letter flap assembly comprising a frame, a letter flap and a pair of end caps, the letter flap being pivotally mounted at its opposite ends on the end caps, the -21 -frame, the pair of end caps and the letter flap being able to be assembled together into an operational state without any auxiliary fasteners and being able tc be dissembled and re-assembled repeatedly.
31. An assembly according to claim 30, further including screw threaded fasteners for securing the end caps to the frame and thereby securing the pivotal mounting of the letter flap on the end caps.
32. An assembly according to claim 30 or 31, in which the end caps and the opposite ends of the frame are push-fitted together.
33. An assembly according to any of claims 30 to 32, in which the end caps have male formations engaging female formations at opposite ends of the frame.
34. An assembly according to claim 33, in which the frame is an extrusion and opposite ends of one or more channels in the frame define the female formations.
35. An assembly according to claim 34, in which the one or more channels are each open on one side.
36. An assembly according to any of claims 30 to 35, in which the frame is of generally elongate rectangular shape and interengaging formations of the end caps and the frame are provided at both upper and lower regions of the opposite ends of the frame.
37. A letter plate assembly comprising a letter flap assembly according to any preceding claim.
38. A letter plate assembly according to claim 37, -22 -including a further letter flap assembly according to any of claims 1 to 36, the letter flap assemblies being able to be provided on opposite sides of a door.
39. A letter plate assembly aooording to claim 37 or 38, including a box-shaped housing
40. A letter plate assembly substantially as herein described with reference to the accompanying drawings.