IE20010195A1 - Spring cassette - Google Patents

Abstract

In a spring cassette (11) for a door lever handle, the casing of the cassette (11) consists of two substantially identical portions (21) engaged together to enclose a cam follower (31) and two spring guides (41) with associated springs (44). The cam follower (31) has a profiled central aperture (32) for reception of the spindle of a door handle. The follower (31) is rotatable within the casing (21) and co-operates with the spring guides (41), each of which has a camming surface (45) for co-operating engagement with a respective peripheral camming portion of the cam follower (31). The guides (41) slide within the casing (21) when the follower (31) is rotated and are urged against the follower (31) by the compression springs (44) which act between abutment portions (47) of the respective guides (41) and fixed abutments (24,28) of the casing (21). The spring guides (41) have spigots (43) which are axially aligned with passageways (22) within the casing (21) in the assembled condition of the unit (11). The compression springs (44) surround the spigots (43) of the guides (41) and are insertable into the spring passageways (22) of the casing (21) through external casing apertures (23) after assembly of the cassette unit (11) with the follower (31) and guides (41) enclosed in the two part casing (21). <Figure 5>

Description

This invention relates to spring cassettes for door levers and door lever plates. The invention is especially directed to the provision of an economical construction of spring cassette which is easy to assemble and Iocatabie in aligned disposition within an door lever plate.

Description of the Prior Art In a first known spring cassette, a plastics housing is provided within which a single-sided springing arrangement is located. A cam follower is penetrated by the spindle of or for the door lever and engages against a sliding member, also of plastics, which is guided within the plastics housing for displacement when the cam follower is rotated. Displacement of the sliding member and thus rotation of the cam follower is resisted by the slider being spring biased towards a disposition of the cam follower corresponding to a horizontal position of the door handle, namely a latching position. The slider member is provided with three plastics columns or pillars, the ends of which remote from the slider are guided within matching apertures or guideways of the plastics housing. The biasing springs are located in a manner surrounding the respective pillars and are held between the slider member and an abutment face of the plastics housing.

This arrangement requires a number of different components and presents difficulties in assembly.

In a second known construction of a spring cassette, a housing is provided by a plate member with upstanding side and end portions, the upstanding side portions being bent over in their free end region to grip over and hold in place a pair of sliders, one located to each side of a centrally placed cam follower which is rotated by the spindle of or for the door lever. The upstanding end portions of the housing define abutments for springs which are held between these end abutments and spring receiver regions of the sliders. The sliders are substantially block-shaped and are formed from a plastics material, as also is the follower. The spring receivers are defined by blind holes extending from the end faces of the sliders directed towards the abutment portions of the housing in the assembled unit.

Again, this spring cassette requires a number of different components and presents certain difficulties in assembly, precluding easy and economical putting together of the unit.

BRIEF SUMMARY OF THE INVENTION It is an object of the invention to provide an improved spring cassette which will require a lesser number of a complex components than prior art structures and which will in particular facilitate easy and economical assembly.

According to the invention, there is provided a spring cassette for a door lever handle, comprising (1) a casing receivable in a door lever handle plate, (2) a cam follower having a profiled through aperture for reception of a handle spindle, the follower being rotatable within the casing, (3) at least one spring guide having a camming surface for co-operating engagement with a camming surface of the cam follower, the guide being translationally displaceable within the casing on rotation of the follower, and (4) at least one spring operatively engaged between a respective receiving portion of the spring guide and a fixed portion of the casing in order to bias the guide against the follower, wherein the casing comprises two portions engaged together to enclose the cam follower and the or each spring guide and spring.

In a preferred embodiment, each casing portion is substantially identical with the other casing portion. In particular, each casing portion may be a diecast component.

The or each spring guide suitably has at least one spring receiving portion, the or each spring receiving portion being defined by a spigot extending from a region of the guide directed away from the camming surface of the spring guide. The or each spigot may be located within a spring-accommodating passage defined within the casing in an assembled condition of the spring cassette and the casing may have an aperture communicating between said spring accommodating passage and an external surface of the casing, for insertion of a spring following assembly of the follower and spring guide within the casing.

In a favoured arrangement, the or each spring guide has two spigots, each being located within a respective spring-accommodating passage defined within the casing in the assembled condition of the spring cassette, and said passages being disposed in the vicinity of lateral regions of the casing with a through aperture penetrating the casing between said passages. In any embodiment of the invention, the casing is suitably substantially rectangulate and two spring guides are provided, the spring guides being disposed within the casing to each longitudinal side of a substantially centrally located cam follower.

In a second aspect, the invention provides a spring cassette for a door lever handle, comprising (1) a casing receivable in a door lever handle plate, (2) a cam follower having a profiled through aperture for reception of a handle spindle, the follower being rotatable within the casing, (3) at least one spring guide having a camming surface for co-operating engagement with a camming surface of the cam follower, the guide being translationally displaceable within the casing on rotation of the follower, and (4) at least one spring operatively engaged between a respective receiving portion of the spring guide and a fixed portion of the casing in order to bias the guide against the follower, wherein the spring receiving portion of the spring guide is defined by a spigot extending from a region of the spring guide directed away from the camming surface of the spring guide, and the spigot is located within a spring-accommodating passage defined within the casing in an assembled condition of the spring cassette.

According to a further aspect of the invention, there is provided a spring cassette for a door lever handle, comprising (1) a casing receivable in a door lever handle plate, (2) a cam follower having a profiled through aperture for reception of a handle spindle, the follower being rotatable within the casing, (3) at least one spring guide having a camming surface for co-operating engagement with a camming surface of the cam follower, the guide being translationally displaceable within the casing on rotation of the follower, and (4) at least one spring operatively engaged between a respective receiving portion of the spring guide and a fixed portion of the casing in order to bias the guide against the follower, wherein the or each spring is insertable into an assembly of the casing, cam follower and spring guide through an aperture in an external surface of the casing, for engagement of the spring between said receiving portion of the spring guide and said fixed portion of the casing.

In a preferred construction of the invention in this further aspect, the or each spring guide has at least one spring receiving portion, the or each spring receiving portion being defined by a spigot extending from j region of the guide directed away from the camming surface of the spring guide, and the or each spigot may be located within a spring-accommodating passage defined within the casing in an assembled condition of the spring cassette.

The invention also extends to a set of components for providing a spring cassette according to any of the preceding definitions, as well as to the spring cassette in combination with a door plate assembly or in combination with a door plate and handle assembly. The invention likewise also embraces a spring cassette substantially as described herein with reference to and as shown in Figure 5 of the accompanying drawings, a spring cassette and door plate assembly substantially as described herein with reference to and as shown in any one or more of Figures 1, 2 and 5 of the accompanying drawings, and a spring cassette, door plate and handle assembly substantially as described herein with reference to and as shown in any one or more of Figures 5, 6 and 7 of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the invention and its manner of application will now be described with reference to the accompanying drawings, in which: Figure 1 shows a door lever plate positioned to receive a spring cassette according to the invention, Figure 2 shows the spring cassette of Figure 1 received within the door lever plate of Figure 1, Figure 3 is an exploded pictorial representation of a first prior art spring cassette, Figure 4 is an exploded pictorial representation of a second embodiment of prior art spring cassette, Figure 5 is an exploded view of a spring cassette according to the invention, Figure 6 is a further view showing a spring cassette according to the invention in position for association with a door plate and handle, and Figure 7 shows the cassette, door plate and handle of Figure 6 in the fully assembled position with the cassette received within the door plate.

A door plate 1 of substantially conventional configuration is shown in Figure 1.

A spindle of or for the handle is received within an aperture 2 through the front face of the door plate 1. The door plate 1 has, at its opposite ends, pillars 3 through which screws may be inserted to secure the door plate 1 to a door. In the vicinity of the spindle location 2, the door plate 1 is also provided with a further internally threaded or unthreaded pillar 4, used for bolting through the door.

The spring cassette 11 according to the invention is placed in position within tlie door lever plate 1 to be received in an inside cassette-receiving cavity or recess 5 of the plate 1, which substantially matches the generally rectangular external configuration of the cassette 11. The cassette 11 of the invention resembles a rectangular box or case in configuration; with a longitudinal dimension, a transverse dimension and a depth which is relatively shallow with respect to the other dimensions of the unit. The cassette 11 may also be fully symmetrical in its construction, so that it may be placed into the door plate 1 with either of its larger area faces inwards, although symmetry of fitting is not necessarily provided in all embodiments. The cassette 11 is provided with two symmetrically placed through holes 12 of a diameter suitable to locate with clearance around the exterior of the internally threaded or unthreaded pillar 4 used for bolting through the door. The symmetrical arrangement of these holes 12 provides that one hole 12 is located to each side of a central spindle-receiving hole 13 of the cassette 11 in the direction of the longitudinal axis of the cassette 11. The cassette 11 is fitted over and in alignment with the door lever spindle bar, so that the square plug end of the spindle is accommodated within a square through hole 32 defined in the cam follower 31 of the cassette 11 (see Figure 5).

The assembled door plate 1 and cassette unit 11 is shown in Figure 2, in which it will be seen that the spindle aperture 32 of the cam follower 31 (Figure 5) is aligned with the spindle-receiving opening 2 of the door plate and the through bolting threaded or unthreaded pillar 4 has been received within one of the apertures 12 of the cassette 11. The arrangement is especially suitable for door locks which are European in style, i.e. locks which have a sliding rail in a recess on the edge of the door. Locking arrangements of this kind require the door lever handle to be rotated upwards in order to move the sliderail vertically to engage four locking points. Downward rotation of the handle serves to retract the springbok for normal opening and closing of the door. The arrangements also allow the key to be turned to create a deadlocking situation to give a fifth locking point. Locks in which the cassette arrangement is applied may also be of the nightlatching kind. A key is required to gain entry from the outside of the door and the handle is only used to throw the sliderail to allow for external five point locking as described above. Fitting of the spring cassette enables effective and efficient return of the handles to the horizontal position for a great diversity of door mortice locks. 3() Spring cassettes for door lever plates are known and provide a technically advantageous return spring arrangement for door lever handles as compared with EC 10195 independent spring arrangements requiring individual assembly within the door lever plate. A first construction of known spring cassette is illustrated in Figure 3 and provides a single sided arrangement in which suitably a metal cam follower 61 is received within a laterally open or side slotted end region 52 of a plastics housing 51. The housing 51 is of generally rectangulate configuration with an axial or longitudinal dimension, a shorter transverse dimension and a lesser depth dimension. The cam follower 61 can thus be slid into place at this end of the housing 51 through and from one of the slide slots 52. The transverse end 53 of the generally rectangular cassette housing 51 at the side slot end 52 of the housing 51 is closed off to one side of the cam follower 61, and provides a bearing face for the cam follower 61 during rotation of the follower 61. The cam follower 61 is urged against this bearing face by a sliding biasing member or slider 65 which is itself urged by means of three compression springs 66 against the cam follower 61. Side spigots 67 of the sliding member 65 travel within the side slots 52 at this cam follower accommodating end of the housing 51 for guidance of the slider 65. The springs 67 (two of three shown) are located about and surround three axial columns or pillars 68 which extend from the slider member 65 along the housing 51 towards its axial end 54 which is opposite to the cam follower end 53. The pillars 68 are guided at their free ends within matching internal bores 55 formed at that end 54 of the plastics housing 51. The springs 66 are compressively biased between an abutment face on the side of the slider 65 directed away from the cam follower 61 and a fixed end abutment face 56 of the housing 51, where the guide columns 68 pass into the guide bores or apertures 55 of the housing 51. When the cam follower 61 is rotated, the slider 65 is pushed towards the spring abutment face 56 end of the housing 51, and the resulting increased compressive spring force provides a return action on the cam follower 61, so as to return the door handle to a door closed disposition.

A further prior art arrangement is shown in the exploded pictorial representation of Figure 4. In this case, the construction is partially symmetrical, with spring-biased slider members 85 located one to each side of a central cam follower 81. Both sliders 85 and cam follower 81 are formed from plastics in this arrangement. All three components 81, 85 are housed within a metal structure 71, which has a back plate 72 from which upstanding side portions 73 extend and overlap, at bent-over upper free ends 74, upper faces of side regions 86 of the sliders 85 in this generally rectangular construction. As in the case of the cassette of the invention and that of Figure 3, a rectangulate construction is in question, having a length dimension, a width dimension and a shallower depth dimension. References to orientation, viz, upstanding, upper etc, relate solely to the arrangement as depicted in Figure 4 and do not define any preferred disposition of the assembled unit in use or as installed. At the ends of the generally rectangular metal housing 71, further upstanding portions 75 define spring abutments. Two springs 87 (one shown) for each slider 85 are interposed between these fixed abutment faces 75 and abutment regions of the sliders 85 defined at the inner ends of blind holes 88 extending inwards from the end faces 89 of the sliders 85 directed towards the spring abutments 75. The holes 88 extend from these end faces 89 towards the cam follower ends of the sliders 85, in which region they terminate at blind abutment ends. In this case again, rotation of the cam follower 81 urges the two sliders 85 outwards from the centre of the housing 71 against the returning force of the respective springs 87. The housing back plate 72 is provided with holes 76 which are symmetrically placed along the longitudinal axis of the housing member 71 with respect to the larger diameter central aperture 77 within which the cam follower 81 is located for alignment with the handle spindle in a door plate. These holes 76 allow passage of an internally threaded or unthreaded pillar of the door plate, as already described in connection with Figures 1 and 2. The respective sliders 85 are likewise provided with through apertures 91, of elongate or slot shape, to allow passage of this threaded or unthreaded pillar through the assembled spring cassette unit.

The cassette arrangement provided by this prior art structure is not however fully symmetrical in all respects, and neither are its component parts fully interchangeable or symmetrical. In particular, the cam follower 81 has a collar portion, not visible in the exploded pictorial view of Figure 4, on the lower side of the cam follower 81 as depicted in that representation, for location of the cam follower 81 within the central aperture 77 of the back plate 72 of the housing member 71. The presence of this collar is indicated by the increased depth of the cam follower 81 around the .square spindle aperture in the follower.

The slider members 85 are identical as between each other, but are not symmetrical as between their upper and lower faces as depicted in Figure 4. The inner or follower engaging end of each slider 85 is provided with a slot 92 for co-operation with the peripheral camming surface or edge of the follower 81. The upper surface of each slider 85 as depicted in the drawing is provided with a recess or indentation 93, from the base of which the elongate slot 91 for accommodation of the threaded or unthreaded door plate pillar 4 extends though the body of the slider portion 85. When the sliders 85 are assembled within the housing structure 71, these recesses are in the upwardlydirected faces of the sliders 85. Upward, downward, etc again refer only to the orientation of the components as depicted in Figure 4 and do not imply any delimiting quality. Thus both cam follower 81 and sliders 85 can only be assembled in a particular orientation with respect to the housing portion 71.

Both of these prior art arrangements have certain disadvantages in manufacture and assembly, whether as to number of parts or ease of assembly, and it is to overcoming such difficulties that the present invention is directed.

Referring now to Figure 5, the spring cassette 11 of the invention is shown in exploded view. A particularly simple structure is provided. The cassette housing 11 is put together from two zinc diecast case portions 21, which are identical, so that only a single mould is required to provide the two parts 21 of the case 11. The single cam follower 31 is provided substantially in known manner, and this is biased into the central door lever horizontal or door-closed disposition by two spring guides 41, which are again identical, so that only a single mould is needed to provide the two guides 41 for each cassette 11. A symmetrical cam follower 31 may be provided, so that it can be placed in position within the casing portions 21 without reference to which side of the follower faces which casing portion. Alternatively, the cam follower 31 may be noiluniversal, in that the square spindle-receiving aperture 32 in the follower cam 31 may be rotated by approximately three to five degrees from a fully square orientation with respect to the assembled cassette unit. Such rotation may be required to compensate for spindle to handle core-hole tolerance. This variation in construction thus deals with the presence of a small degree of play between the spindle and the handle, and is directed to avoiding excessive droop of the handle in the installed condition. It will be appreciated that when such a modification is applied to the aperture 32 and the follower 31, full universality of cassette fitting will not apply. However, other than the follower 31, the symmetrical features of the remaining components of the unit and the associated ease of assembly continues to prevail. The spring guides 41 are of particularly simple and lightweight construction as compared with prior art arrangements and this is achieved by each spring guide 41 having a relatively small body portion 42 from which there extends a pair of pillars 43. The pillars 43 are guided within guideways 22 defined half and half in each portion 21 of the case 11. The spring guides 41 are loaded by means of compression springs 44 and the case portions 21 are provided with external apertures 23 through which the springs 44 may be inserted into position in the guideways 22 to surround the pillars 43. This insertion can be readily effected after the case 11 is assembled with the spring guides 41 and cam follower 31 in its interior. Suitable locating means such as small spigots or protrusions 24 provide for end retention of the springs 44 at the fixed abutment end 28 of the guideways 22, where the springs are engaged in the case 11.

These various features of the invention will now be described in detail. All references to orientation, such as upper, lower, etc, relate to the depiction of the unit in Figure 5 and are not intended to imply any limitation in orientation or disposition of the unit as assembled and applied to a door plate. In a particular construction, the assembled cassette unit 11 is fully symmetrical and can be reversed or inverted, so that it can be placed in position in a door plate in any one of its four possible orientations. However, as previously indicated, depending on whether it is necessary to provide for offset or rotation of the aperture hole 32 in the cam follower 31, full universality of fitting may not be available in all circumstances. The various components or parts of the unit 11 are however themselves symmetrical, either fully so, or about at least one axis of symmetry, thereby facilitating the task of assembly of a unit in accordance with the invention. This symmetry of the components with respect to themselves applies to all components, other than possibly the cam follower 31, so that the advantages of a small number of moulds and component parts prevails in all embodiments of the invention, while also substantial universality of assembly ofthe unit 11 is available irrespective of whether or not there is skewing of the central aperture 32, and it is only in fitting the assembled cassette 11 to a door lever plate 1 and handle 6 that the question of any non-universality arises.

Referring first of all to the case 11, and referring in particular to the inner side of the identically formed upper and lower case portions 21, there is a central recessed region 25 within the zinc diecast case 21 in which first of all the cam follower 31 is accommodated in substantially conventional manner. The follower 31 has a central square aperture 32 through which the handle spindle is engaged and this central aperture 32 is surrounded on each large area side or face of the follower by a collar portion or hollow spigot 33 by which the follower 31 is located in a face aperture 13 of the top and bottom case portion 21 respectively. A fully symmetrical construction of cam follower 31 is thereby provided. As also previously discussed however, the cam follower 31 may be nonsymmetrical by virtue of the central aperture 32 being skewed or rotated through a small angular extent to provide for spindle to handle play. The cam follower 31 has camming portions 34 formed in conventional manner for loading or bearing against the spring sliders 41 when the follower 3 1 is rotated.

Returning again to the case structure 11, the central cavity or recess 25 of the case 21 is of sufficiently large dimension to also accommodate to sliders 41, each of which has a substantially bridge-shaped configuration in plan view, with a central face 45 which is engaged by the cam follower 31 during rotation of the follower 31. At the ends of the central face 45 there are downwardly extending portions 46, relative to the general structure of the slider 41, to enable smooth camming engagement of the slider 41 on rotation of the follower 31. Portions 46 are directed therefore towards the cam follower 3 1 in the assembled cassette unit. The slider 41 is of short dimension therefore in the axial direction of the assembled unit 11, but extends over substantially the full width of internal recess or cavity 25 in the transverse dimension of the unit.

The sliders 41 are thus located within the cavity or recess 25 of the case so as to extend across the cavity 25 in the shorter dimension of the case 11, the elongate 3() dimension of the slider 41 being transverse across the case structure 11. Each slider 41 has a face opposite 47 to that which is engaged by the cam follower 31. The two spring guide pillars 43 extend from this face 47. Each of these spring guide pillars 43 is aligned within a slot portion or groove-type recess moulded into each case half 21 on its inner side, in such a manner that when the two case halves 21 are brought together, a substantially cylindrical passage 22 is defined in the interior of the assembled casing 11. The pillars 43 of the spring guides 41 are displaceable within these passages and the compression springs 44 are accommodated in these substantially cylindrical guideways 22. The spring guideways 22 extend from end edge regions 26 of the central cavity 25 of the case 11 towards the outer ends 27 of the case, in its elongate direction. The guideways or channels 22 terminate however at dead ends or spring abutment fares 28 short of the actual transverse ends of the housing 11, which are fully closed.

The outer end regions 23 of these guide pillar and spring accommodation slots 22 are open to the exterior of the case 11 on the larger area external faces of the case, two diagonally opposite such regions 23 being externally open on each half 21 of the case structure 11. These openings 23 are apparent in both the view of the bottom case portion and also in the view of the top case portion in Figure 5. The guide passages or bores 22 terminate towards the end regions of the case 11 in the elongate direction at the spring abutment faces 28. These abutment faces are plain transverse features at the passage ends in the casing half not having a spring-loading aperture 23 for the passage in question. Locating portions or small spigots 24 for retaining the springs 44 in position when inserted into the assembled casing unit 11 are then provided at the matching and co-operating abutment ends of the passage portions 22 in the other casing half 21, in which the respective spring-insertion openings 23 are provided.

Further outward of the outward ends 28 of the guide apertures or bores 22, in the elongate direction, each case portion 21 is also provided with an upstanding spigot 15 on its inner face and a matching through hole 16 for receiving a co-operating spigot 15, these being arranged in symmetrical diagonal opposition, so that when an upper case portion 21 is placed over a lower case portion 21, the portions 21 being however structurally identical, each spigot 15 of one case portion 21 engages in and substantially through an aperture or bore 16 of the other. Following such assembly, the spigots 15 are penned over to form a closed and sealed sandwich case construction 11.

The spring cassette comprises four compression springs 44, each of which is located in the assembled unit 11 over a respective pillar 43 of a spring guide 41 and accommodated within one of the guide passages or botes 22 within the assembled structure 11.

Assembly of a unit 11 in accordance of the invention takes place in the following manner. The cam follower 31 and the two spring guides 41, one to each side of the cam follower 31, are loaded into one of the two identical zinc case portions 21. A second case portion 21 is then laid in position over the first case portion 21, so that the fastening spigots 15 of each case portion 21 engage through the co-operating fastening apertures or bores 16 of the other case portion 21. The four spigots 15 are then penned over to secure the two casing portions 21 together with the follower 31 and spring guides 41 held between them. The follower 31 is rotatable within the closed cavity region 25 formed within unit 11 when the two casing portions are brought together, and the spring guides 41 are slidingly displaceable on each side of the cam follower 31, also within this central cavity 25. The cavity 25 is defined in a closed manner within the casing 11 when the two casing portions 21 are secured together. The four compression springs 44 may now be inserted through the insertion apertures 23, two on each outer face 18 of the assembled casing 11. The springs 44 are introduced through the respective insertion apertures 23 and are pushed downwards over a respective guide pillar or spigot 43 of the respective guide portion 41. During the initial assembly together of the casing portions 21, when the spring guides 41 are placed in position within the main body portions 21 within the central cavity 25, the pillars 43 are located within the matching respective guide passages 22 defined by the slot portions or grooves in each casing half when the unit is closed. Each spring 44 is then in turn compressed downwards and its free end is snapped into position within the spring aperture 23, so that its free end face engages against and over the protrusion-equipped abutment end 28 of the spring aperture 23 and is held in place by a respective protrusion 24.

The assembled product can then be fitted in alignment with the door lever spindle bar receiver 7 (Figure 6) and at the same time located in the inside cavity 5 of the door lever plate 1. The square spindle is subsequently engaged in receivers 7 of the door handle assembly when the assembly is applied to and secured to the door. These further steps are shown again, from a different angle, in Figures 6 and 7. Clearance holes 12 of suitably 9ntm diameter provided through the respective casing portions 21 enables the spring cassette be located around the internally threaded or unthreaded pillar 4 used for bolting through the door. The casing construction 11 is symmetrical so that either hole 12 may be used. A particular advantage of the present construction is that the lever plates 1 on each side of the door may be bolted together without in any way interfering with the spring mechanism, in that the spring guides 41 do not engage in any way against the sides of the through bolt pillar 4 of the door plate 1, In the prior art arrangement of Figure 4, it will be seen that the spring guides 85 may be in sliding relation to this pillar 4, thereby leading to the possibility of greater friction and possible binding of the spring guides 85, should there be any lateral misalignment, or impingement of any other undesirable forces.

It will be particularly apparent from the foregoing description that in one embodiment of the invention, the assembled casing 11 can be located with either of its larger area faces 18 introduced into the door plate 1, and it can also be positioned in either end-to-end disposition. In other words, it may be fully universal as to fitting, thereby providing full versatility during assembly with the door plate 1. However, even where universality of fitting is not provided, substantial universality of assembly of the cassette unit itself is available, using the substantially symmetrical components without reference to any kind of handing or different orientational requirements, and it is only when fitting the cassette to the door plate that it is required to take recognition of the possible rotation or skewing of the square aperture 32 in the cam follower 3 I. The structure 11 is suitably designed and constructed so that a handle 6 may be returned to horizontal from a position as far displaced as 90 degrees, whether clockwise or anticlockwise, by appropriate selection of spring dimensions and characteristics.

The words “comprises/comprising” and the words “having/including” when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

Claims (29)

1. r CLAIMS

1. A spring cassette for a door lever handle, comprising (1) a casing receivable in a door lever handle plate, 5 (2) a cam follower having a profiled through aperture for reception of a handle spindle, the follower being rotatable within the casing, (3) at least one spring guide having a camming surface for co-operating engagement with a camming surface of the cam follower, the guide being translationally displaceable within the casing on rotation of the follower, and lo (4) at least one spring operatively engaged between a respective receiving portion of the spring guide and a fixed portion of the casing in order to bias the guide against the follower, wherein the casing comprises two portions engaged together to enclose the cam follower and the or each spring guide and spring.

2. A spring according to Claim 1, wherein each casing portion is substantially identical with the other casing portion.

3. A spring cassette according to Claim 1 or Claim 2, wherein each casing portion is a 20 diecast component.

4. A spring cassette according to any preceding claim, wherein the or each spring guide has at least one spring receiving portion, the or each spring receiving portion being defined by a spigot extending from a region of the guide directed away from the 25 camming surface of the spring guide.

5. A spring cassette according to Claim 4, wherein the or each spigot is located within a spring-accommodating passage defined within the casing in an assembled condition of the spring cassette.

6. A spring cassette according to Claim 5, wherein the casing has an aperture communicating between said spring accommodating passage and an external surface of t the casing, for insertion of a spring following assembly of the follower and spring guide within the casing.

7. A spring cassette according to Claim 5 or Claim 6, wherein the or each spring guide has two spigots, each being located within a respective spring-accommodating passage defined within the casing in the assembled condition of the spring cassette, and said passages being disposed in the vicinity of lateral regions of the casing with a through aperture penetrating the casing between said passages.

8. A spring cassette according to any preceding claim, wherein the casing is substantially rectangulate and two spring guides are provided, the spring guides being disposed within the casing to each longitudinal side of a substantially centrally located cam follower.

9. A spring cassette for a door lever handle, comprising (1) a casing receivable in a door lever handle plate, (2) a cam follower having a profiled through aperture for reception of a handle spindle, the follower being rotatable within the casing, (3) at least one spring guide having a camming surface for co-operating engagement with a camming surface of the cam follower, the guide being translationally displaceable within the casing on rotation of the follower, and (4) at least one spring operatively engaged between a respective receiving portion of the spring guide and a fixed portion of the casing in order to bias the guide against the follower, wherein the spring receiving portion of the spring guide is defined by a spigot extending from a region of the spring guide directed away from the camming surface of the spring guide, and the spigot is located within a spring-accommodating passage defined within the casing in an assembled condition of the spring cassette.

10. A spring cassette according to Claim 9, wherein the casing has an aperture communicating between said spring accommodating passage and an external surface of the casing, for insertion of a spring following assembly of the follower and spring guide within the casing.

11. A spring cassette according to Claim 9 or Claim 10, wherein the or each spring guide has two spigots, each being located within a respective spring-accommodating passage defined within the casing in the assembled condition of the spring cassette, and said passages being disposed in the vicinity of lateral regions of the casing with a through aperture penetrating the casing between said passages.

12. A spring cassette according to any of Claim 9 to 11, wherein the casing is substantially rectangulate and two spring guides are provided, the spring guides being disposed within the casing to each longitudinal side of a substantially centrally located cam follower.

13. A spring cassette according to any of Claims 9 to 12, wherein the casing comprises two portions engaged together to enclose the cam follower and the or each spring guide and spring.

14. A spring according to Claim 13, wherein each casing portion is substantially identical with the other casing portion.

15. A spring cassette according to Claim 13 or Claim 14, wherein each casing portion is a diecast component.

16. A spring cassette for a door lever handle, comprising (1) a casing receivable in a door lever handle plate, (2) a cam follower having a profiled through aperture for reception of a handle spindle, the follower being rotatable within the casing, (3) at least one spring guide having a camming surface for co-operating engagement with a camming surface of the cam follower, the guide being translationally displaceable within the casing on rotation of the follower, and (4) at least one spring operatively engaged between a respective receiving portion of the spring guide and a fixed portion of the casing in order to bias the guide against the follower, wherein the or each spring is insertable into an assembly of the casing, cam follower and spring guide through an aperture in an external surface of the casing, for engagement of the spring between said receiving portion of the spring guide and said fixed portion of the casing.

17. A spring cassette according to Claim 16, wherein the or each spring guide has at least one spring receiving portion, the or each spring receiving portion being defined by a spigot extending from a region of the guide directed away from the camming surface of the spring guide.

18. A spring cassette according to Claim 17, wherein the or each spigot is located within a spring-accommodating passage defined within the casing in an assembled condition of the spring cassette.

19. A spring cassette according to Claim 18, wherein the or each spring guide has two spigots, each being located within a respective spring-accommodating passage defined within the casing in the assembled condition of the spring cassette, and said passages being disposed in the vicinity of lateral regions of the casing with a through aperture penetrating the casing between said passages.

20. A spring cassette according to any of Claims 16 to 19, wherein the casing is substantially rectangulate and two spring guides are provided, the spring guides being disposed within the casing to each longitudinal side of a substantially centrally located cam follower.

21. A spring cassette according to any of Claims 16 to 20, wherein the casing comprises two portions engaged together to enclose the cam follower and the or each spring guide and spring.

22. A spring according to Claim 21, wherein each casing portion is substantially identical with the other casing portion.

23. A spring cassette according to Claim 21 or Claim 22, wherein each casing portion is a diecast component.

24. A spring cassette substantially as described herein with reference to and as shown in Figure 5 of the accompanying drawings.

25. A set of components for providing a spring cassette according to any preceding claim.

26. A door plate assembly in combination with a spring cassette according to any of Claims 1 to 24.

27. A door plate and handle assembly in combination with a spring cassette according to any of Claims 1 to 24.

28. A spring cassette and door plate assembly substantially as described herein with reference to and as shown in any one or more of Figures 1,2 and 5 of the accompanying drawings.

29. A spring cassette, door plate and handle assembly substantially as described herein with reference to and as shown in any one or more of Figures 5, 6 and 7 of the accompanying drawings.