1

A STAIRCASE

The present invention relates to improvements in staircases and a method of manufacturing thereof.

The basic components of a staircase are treads, stringers and a balustrade. Treads are the horizontal portion of the steps of a staircase that a person walks on whilst stringers are the sides of the stairs which are routed to accept the treads. The balustrade comprises newels, balusters and a handrail. The newels are the larger vertical posts generally found at the beginning and end of the staircase and occasionally found in between each end to provide additional support to the balustrade. The balusters are the smaller more numerous vertical posts that support the handrail between the newels.

There are four basic types of staircase, straight, flared, curved or spiral. A straight staircase can be split with a landing to form either a U or L shaped staircase. In a flared staircase a number of the first steps are flared to give the impression that the staircase is actually curved. A curved staircase has steps that follow a constant radius or arc of a circle and a spiral staircase is where the treads are supported on a central pole. One method of forming a spiral staircase uses a steel pipe as the central pole. The treads have a hole at one end that enable each tread to be dropped over the pipe. In between each tread a short piece is dropped over the centre pole thus separating each tread. When all of the treads are in position a threaded pipe is then screwed onto the centre pole tightening everything in place.

More traditional staircases have a returned tread, this is where the side edge of the tread is seen from the open side(s) of the staircase. In comparison most modern staircases have a closed stringer, where the treads are not visible from the open side(s) of the staircase, a short framed wall known as a 'knee wall' holds the balusters. The number of balusters required on a returned tread staircase is significantly more than the number required for a closed stringer staircase. Furthermore the treads on a traditional staircase generally have a mitered return to give a finished side edge. Thus the cost of having a returned tread staircase is significantly more than that of a closed stringer staircase.

GB 2,370,622 discloses a new wood joint comprising one element formed into a bifurcated end and a second element having orifices which accommodate the bifurcations each bifurcated end comprising a pair of parallel legs joined by a V- or U-shaped section, wherein the generally V- or U-shaped section is not concealed in the assembled joint.

It is the object of the present invention to provide a plurality of elements, which when combined form a staircase having strong jointing structure. The present invention also provides a method for combining the elements together to form a staircase, which is robust and is relatively easy to manufacture.

The present invention provides a spiral staircase, comprising

(a) a first element corresponding to a baluster comprising two ends, the first end formed into a bifurcated end, the bifurcated end comprising one or more pairs of parallel legs, the legs being joined by a V- or U-shaped section;

(b) a second element corresponding to a tread comprising two ends, the first end having orifices which accommodate the bifurcations of the first element and a second end formed into a bifurcated end, the bifurcated end comprising one or more pairs of parallel legs, the legs being joined by a V- or U-shaped section, wherein the generally V- or U-shaped section is not concealed in the assembled joint;

(c) a third element corresponding to a central pole having orifices which accommodate the bifurcations of the second element, wherein the generally V- or U-shaped section is not concealed in the assembled joint; and

(d) a fourth element corresponding to a handrail comprising a U-shaped element which is placed over the second end of the first element, the second end of the first element inserting into the channel of the U-shaped element.

The present invention also provides a method of manufacturing a spiral staircase, comprising the steps of;

(a) supporting a central pole;

(b) forming orifices on the central pole;

(c) inserting and securing one or more treads into the orifices of the central pole, each tread comprising two ends, the first end having orifices which accommodate the balusters of the invention and a second end formed into a bifurcated end which is

inserted into the orifices of the central pole, the bifurcated end comprising one or more pairs of parallel legs, the legs being joined by a V- or U-shaped section, wherein the generally V- or U-shaped section is not concealed in the assembled joint;

(d) inserting one or more balusters into the orifices on a tread, each baluster comprising two ends, the first end formed into a bifurcated end for insertion into the orifices on the tread, the bifurcated end comprising one or more pairs of parallel legs, the legs being joined by a V- or U-shaped section wherein the generally V- or U- shaped section is not concealed in the assembled joint; and

(e) placing a handrail comprising a U-shaped element over the second end of the baluster, the second end of the baluster inserting into the channel of the U-shaped element.

Preferably a base unit is provided for each spiral staircase which provides stability and support for the central pole.

Optionally the central pole comprises a plurality of sections that are removably securable to each other. In the preferred embodiment of the invention each central pole section is cylindrical having a first and second end, the first end having a recess and the second end having a projection whereby the projection is complimentary in shape to the recess. Thus when the central pole is being assembled the projection on one central pole section inserts into the recess of an adjacent central pole section. Conveniently it is not necessary for the extremities of the central pole at the top and bottom of the staircase to have a projection or recess. Optionally the end section of the central pole at the bottom of the stairs has a projection or recess to insert into or be placed over the base unit. Optionally, a decorative piece can be inserted into the recess of the central pole section at the top of the staircase.

Optionally the treads are provided with a tread support. Conveniently the tread support is provided as a beam attached to the bottom of the tread, where the bottom of the tread is defined as the underside of the tread which is not walked on. It is to be understood that the tread support is not limited to this type of support and any suitable support known to a person skilled in the art can be used. Ideally the tread support is formed with a projection that resembles one of the prongs of the bifurcated end of the tread. Conveniently the central pole contains additional orifices to receive the projection of the tread support.

Optionally a guide piece is provided, having a series of spaced apart orifices at the top and bottom of the guide piece, the orifices corresponding to the position of adjacent treads. Conveniently the position of the orifices has been calculated to determine the space between sequential treads on the staircases.

Ideally in use the guide piece is placed at the bottom of the central pole and the position of both sets of orifices are marked, the guide piece is then moved upwards, so that the bottom orifices on the guide piece are positioned over the top marked orifices on the central pole, the position of the next set of orifices are marked on the pole and so forth until all the markings for the orifices to receive the treads are complete. Conveniently the guide piece can be readily adapted to also provide guidance for the position of the orifice to receive the tread support on the central pole.

Advantageously the bifurcated end of the balusters are provided with parallel legs of unequal lengths to facilitate positioning the baluster between two adjacent treads. Thus the longer leg of the baluster is positioned on the lower tread whilst the shorter leg of the baluster is positioned on the upper tread. Optionally the bifurcated end of the baluster can also be provided with parallel legs of equal length in order to position the baluster on one tread only. Conveniently, the baluster with parallel legs of equal length can also be used to form a balcony rail or galley rail.

Preferably an intermediate portion is provided between adjacent balusters to provide additional support to the balustrade. Conveniently a plurality interstices are provided on the abutting surfaces of the baluster and the intermediate portions. Ideally a connecting member is positioned in the interstices of the baluster and during construction of the staircase is inserted into the corresponding intermediate portion. Optionally the balusters can have a patterned decorative central portion. Thus a spiral staircase is provided with open returned treads.

The present invention further provides a staircase, comprising;

(a) a first element corresponding to treads and balusters formed into a bifurcated end, each bifurcated end comprising one or more pairs of parallel legs, the legs being joined by a V- or U-shaped section;

(b) a second element corresponding to the stringers comprising a cuboid having orifices on one or more surfaces which accommodate the bifurcations of the first element, wherein the generally V- or U-shaped section is not concealed in the assembled joint; and

(c) a third element corresponding to the handrail having orifices which accommodate the bifurcations of the first element, wherein the generally V- or U-shaped section is not concealed in the assembled joint.

The present invention also provides a method of manufacturing a staircase, comprising the steps of;

(a) forming orifices on a first and second stringer and also a handrail;

(b) inserting and securing one or more treads into orifices on a first surface of the first stringer, each tread having two ends, each end formed into a bifurcated end which is inserted into the orifices on the first and second stringers, the bifurcated end comprising one or more pairs of parallel legs, the legs being joined by a V- or U- shaped section, wherein the generally V- or U-shaped section is not concealed in the assembled joint;

(c) inserting and securing the second end of each attached tread into corresponding orifices on a first surface of the second stringer;

(d) inserting and securing one or more balusters into orifices on a second surface on each of the first and second stringers, each baluster comprising two ends, each end formed into a bifurcated end, a first end for insertion into the orifices on the second surface of each stringer, the bifurcated end comprising one ore more pairs of parallel legs, the legs being joined by a V- or U-shaped section wherein the generally V- or U- shaped section is not concealed in the assembled joint; and

(e) inserting the second bifurcated end of each baluster into orifices on the handrail wherein the generally V- or U-shaped section is not concealed in the assembled joint.

Ideally when the first element is being used as a tread the element is a substantially solid element and the bifurcated ends are quite short. In contrast, when the first element is being used as a baluster, the first element can optionally be quite decorative.

Preferably the stringer is provided as a 'knee wall'.

Conveniently the handrail of the staircase is supported by newel posts at the lower and upper ends of the staircase.

Optionally the balustrade can be extended at the lower and/or upper ends of the staircase to form a balcony rail or a galley rail.

Advantageously, when two or more bifurcations are formed in a series there is provided a plurality of prongs for insertion into the corresponding orifices.

Preferably, the or each bifurcation is formed by a multi-spindle drill drilling holes into the end of the first element, forming the prongs by means of a hole saw and drilling corresponding orifices in the second element using the same multi-spindle drilling machine or one which is set at the same centres as the multi-spindle drilling machine.

Advantageously, the orifices which accommodate the bifurcations of the elements of the invention comprise a plurality of blind holes.

The invention will hereinafter be more particularly described with reference to the accompanying drawings, which show by way of example only, five embodiments of a timber staircase according to the invention. In the drawings: -

Figure 1 is a perspective view of a first embodiment of a staircase of the invention;

Figure 2 is a perspective view of a second embodiment of a staircase of the invention;

Figure 3 is a perspective view of a section of a third embodiment of a staircase of the invention;

Figure 4 is a perspective view of a section of a fourth embodiment of a staircase of the invention;

Figure 5a is a perspective view of an intermediate member of the staircase of the invention;

Figure 5b is a perspective view from the other side of the intermediate member of Figure 5a;

Figure 5c is a perspective view of a balustrade of the staircase of the invention;

Figure 5d is a perspective view of an interstitial connector of the staircase of the invention;

Figure 6a is a perspective view of a section of a handrail of the staircase of the invention;

Figure 6b is a perspective view from the other side of the section of handrail of Figure 6a;

Figure 7 is a perspective view of the bottom portion of a first baluster of the staircase of the invention;

Figure 8 is a perspective view of the bottom portion of a second baluster of the staircase of the invention;

Figure 9 is a perspective view of a template attachable to the centre pole of the staircase of the invention;

Figure 10 is a perspective view of a portion of a centre pole together with an attached tread and tread support and also the template of Figure 9;

Figure 11 is a perspective view of the underside of a tread and tread support attached to a portion of the centre pole of the staircase of the invention;

Figure 12 is a perspective view of a fifth embodiment of a staircase of the invention;

Figure 13 is a perspective view of a sixth embodiment of a staircase of the invention;

Figure 14a is a perspective view of a first decorative central pole section of the staircase of the invention;

Figure 14b is a perspective view of a second decorative central pole section of the staircase of the invention; and

Figure 15 is a perspective view of a balcony rail of the staircase of the invention.

Referring to the drawings and initially to Figure 1 there is shown a first embodiment of a staircase according to the invention. The staircase, indicated generally by reference numeral 100 comprises a base plate 1 , a centre pole 2, a plurality of treads 3 and a balustrade 4, the balustrade 4 comprising a plurality of first balusters 5, a plurality of second balusters 6, a plurality of intermediate members 7 and a handrail 8.

A second embodiment 200 of the staircase is shown in Figure 2. Sections of a third and fourth embodiment 300 and 400 of the staircase are shown in Figures 3 and 4 respectively.

A sixth embodiment 600 of the staircase is shown in Figure 6. The components of the spiral staircase in each embodiment are substantially the same thus the same numerals have been used to indicate each as such.

The construction of the spiral staircase will now be described with reference to Figures 1 to 11 and Figures 13 to 15. A base plate 1 is provided for support and stability of the spiral staircase 100. In this first embodiment 100 the base plate 1 is provided as two sections of wood joined at right angles to each other forming a cross. It is to be understood that the base plate 1 is not limited to this type of base plate. The base plate supports the centre pole 2. The centre pole 2 is formed in sections for example 2a, 2b. Each section being provided with a recess 2c, at one end and a projection at the opposing end. The recess 2c, matches the shape of the projection, thereby enabling the centre pole 2 be constructed by inserting the projection of each section into the recess in the adjacent section. A selection of decorative central pole sections 2g, 2h or 2i can be placed at the top of the central pole 2 by inserting a projection at one end of the decorative section (not shown) into the recess on the adjacent central pole section. A guide piece 11 , is used to indicate the position of the orifices 2d, on the centre pole 2. The guide piece 11 is fitted over the centre pole 2 as shown in Figure 10 and the positions of the opening 11d and 11e corresponding orifices 2d and 2e are marked. The guide piece 11 can then be moved so that the openings 11d are positioned over the orifices 2e and the next set of orifices (not shown) can be marked.

The treads 3 are inserted into the orifices created on the centre pole 2. The treads 3 are provided with an additional tread support 3a or 3b Figure 3 and Figure 4 respectively. The tread support 3a or 3b is a beam which is secured using conventional methods such as screws 3c, Figure 11 to the underside of the tread 3. The tread 3, and balusters 5 and 6 each have one end which is formed into a series of bifurcations or prongs 3e, 5a, 5b and 6a respectively each of which is engagable into corresponding orifices 2d and 3d, Figure 11 formed on the centre pole 2 and tread 3 respectively. The bifurcations are formed by a multi- spindle drill (not shown) drilling holes into the end of the tread 3 and balusters 5 and 6. The prongs 3e, 5a, 5b and 6a respectively are then formed by using a hole saw which forms the cylindrical shape of the prongs 3e, 5a, 5b and 6a respectively. The orifices 2d and 3d in the centre pole 2 and tread 3 are formed by drilling using the same drilling machine, or one which is set at the same centres are used to drill the holes on the tread 3 and balusters 5 and 6.

The prongs 3e of treads 3 insert into the orifices 2d of the centre pole 2. Likewise the prong 3f of the tread support inserts into an orifice (not shown) formed in the same manner as described above on the centre pole 2. The prongs 5a, 5b and/or 6a of the balusters 5 and/or 6 insert into the corresponding orifices 3d on the treads 3. Additional support is provided for the balustrade 4, by inserting intermediate portions 7 between the balusters 5 and/or 6. One or more interstices 9 are provided on the sides of the balusters 5 and/or 6 and also on the sides of the intermediate portion 7, the sides of both the intermediate portion 7 and the balusters 5 and/or 6 being defined as the abutting surfaces.

A connecting member 9a is inserted into the interstice 9 on either the intermediate member 7 or the baluster 5 and/or 6. During construction of the staircase the connecting member 9a is inserted and secured in the corresponding orifice 9 on either the baluster 5 and/or 6 or intermediate member 7 as appropriate. Once the balusters 5 and/or 6 are in position the handrail 8 is constructed. The handrail 8 is formed from U-shaped pieces 8a. The top of the balusters 5 and/or 6 and intermediate portions 7 remote the bifurcated end insert into the channel 8b of the U-shaped piece 8a. Referring specifically to Figure 15, the central pole has a decorative section 2i at the uppermost section. A matching decorative piece 2Oi is used as a newel post at the top of the staircase. The decorative balusters 6B and handrail 80 are extended to form a balcony rail. The handrail 80 attaches to the decorative central rail section 2i and the matching decorative piece 2Oi.

Referring now to Figure 12, there is shown a straight staircase 500 comprising a plurality of treads 30, stringers 70, newel posts 80a and 80b and balustrade 40. The balustrade 40 comprising balisters 60 and handrail 80. The bifurcations of the treads 30 and balisters 60 are formed as previously described, as are the orifices for receiving the bifurcations on the stringers 70 and handrails 80.

Although it is not shown in Figure 12, the balisters 60 and handrail 80 of the balustrade 40 can be extended to form a balcony rail or galley rail.

It will of course be understood that the invention is not limited to the specific details described herein, which are given by way of example only, and that various modifications and alterations are possible within the scope of the invention as defined in the appended claims.