Abstract:
A sash window counterbalance spring mounting arrangement for fitment into a channel section within a window jamb, includes coiled ribbon springs; a spring support mounting including a single integral component for locating and supporting the springs, a support for the springs to support and locate the springs on the mounting, and formed by pairs of triangular cross section projections extending from the rear surface of the main body of the mounting such that when the springs recoil rapidly outer surfaces of adjacent springs contact each other, and including an end portion of the main body which is curved, wing projections extending from the front surface of the main body, and an inter engagement element on the longitudinal end of the mounting for cooperative engagement with cooperative inter engagement features on a sash shoe; and a locating arrangement for locating the mounting within the channel section.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to sash windows and in particular to a mounting for the spring tensioning arrangement used in such sash windows. 
     Modern sash window arrangements utilise flat coiled ribbon springs which are arranged to unwind as the sash is slid and moved within a window frame. The coiled springs provide a counterbalancing force to counterbalance the weight of the sash window thereby making movement, and opening of the window easier. Typically the coiled springs are mounted, via a mounting arrangement, within a vertical channel section of the window frame or jamb. A free end, referred to as a tail, of the spring is connected to a sash shoe slidably mounted within the channel section of the window frame. The shoe in turn is then connected to the sash window jamb, usually towards the lower portion of the sash window. 
     The coil springs are generally of a constant tension type in which the outer profile of the coil itself is rotatably held and supported within the mounting whilst the other free end of the spring is free such that the coil spring can rotate as the spring is unwound and the tail is extended. To provide sufficient force to counterbalance the weight of the sash window multiple springs may be provided with the free ends or tails connected together. 
     An example of a prior arrangement, as generally described above, for a mounting for multiple springs for use in a sash window is described in U.S. Pat. No. 5,365,638. As described in this prior patent, individual mounting means are provided for each of the coil springs. The spring mounting comprises two parallel arranged upstanding wall portions with a coil spring support element interconnecting these wall portions. The coil spring is inserted in between the wall portions with an outer coil surface of the spring supported and resting on the coil spring support element/surface. To provide a multiple spring assembly a number of individual mounting means are provided and stacked into an assembly in the window jamb. 
     Whilst this mounting arrangement, and similar prior arrangements, provide a practical method of mounting and supporting the springs, there are a number of problems with such an arrangement and the mounting arrangement can be improved generally. Particular problems are that the individual mounting for the springs are relatively complex and involve a number of different components. This increases production costs. The individual mountings also have to be installed individually and/or assembled which increases assembly time and costs. Installation of a stack of mountings within the channel section can also in practice be difficult. The installation of the sash shoe can also be problematic, in particular due to the applied tension of the springs which are attached to them. The correct lateral location of the prior mountings within the channel section and alignment of mounting can also be difficult especially due to the restricted access to the channel section. The stack of mountings secured to the jamb via a single screw fitting also have a tendency to undesirably bow under the tension of the springs. If multiple screw fasteners are used to reduce this bowing then assembly time is increased. It has also been found that dirt can accumulate within the mounting assembly and springs. This can adversely affect performance and operation of the counterbalance. The prior art mountings also obstruct the channel section within which the tilt latch is engaged to locate the sash. Consequently the prior art mountings have to be carefully positioned within the jambs such that opening of the window is not restricted. 
     SUMMARY OF THE INVENTION 
     It is therefore desirable to provide an improved sash window spring tensioning mounting arrangement which addresses some or all the above described problems and/or which offers improvements generally. 
     According to the present invention there is provided a sash window counterbalance spring mounting arrangement as described in the accompanying claims. 
     In an embodiment of the invention, which includes a number of complementary and/or separate but related aspects and features of the invention, there is provided a sash window counterbalance spring mounting arrangement for fitment into a channel section within a window jamb. The arrangement comprises at least two coiled ribbon springs, a spring support mounting comprising support means for each of said at least two coiled ribbon springs to support and locate said coiled ribbon springs to the spring support mounting, and locating means adapted, in use, to locate the spring support mounting within and to said channel section. The spring support mounting comprises a single integral component from which the support means depend and from which the at least two springs are located and supported. 
     A spring support mounting comprising a single integral component, ie of a one-piece format, for a multi spring counterbalance arrangement is much simpler to fabricate than the prior multi piece format conventionally used. The single integral format is also much simpler to fit into the channel section than fitting the individual support mountings for each of the multiple springs as used in the prior art arrangements. Using a single integral support mounting component also allows the multiple springs to be more closely located to each other which reduces the potential bowing of the support mounting under the spring load. 
     The spring support mounting comprises an elongate plate like main body portion, the main body portion having a front and rear surface. The support means comprises integral projections from a rear surface of the main body portion. Preferably at least one of the at least two springs comprise a pair of triangular cross section integral projections which extend from the rear surface of the main body portion. The triangular cross section projections are respectively disposed laterally on the rear surface with the respective triangular cross sections laterally oppositely directed such that the pair of triangular projections define a cradle for said spring. 
     Such triangular cross section projections provide a simple and convenient support mounting for the springs. Furthermore they also allow the springs to be located closely together which, as mentioned above, reduces the possibility and problems of bowing of the spring support mounting. 
     An end portion of the main body portion of the support mounting is curved in a direction extending from the rear surface of the main body such that a tip edge of the end portion of the main body is disposed at a position spaced from a plane of the remainder of the main body portion. The end portion is thereby arranged to provide a curved head portion for the spring support mounting. 
     Such a curved head to the spring support mounting allows a tilt latch, which engages within the channel into which the support mounting is fitted, to glide over the installed spring support mounting. 
     When the mounting arrangement is installed within said channel section of the window jamb, the tip edge of the curved head portion is arranged to abut against a wall of said channel section with the curved head portion closing off an end of the mounting arrangement. 
     The abutment of the tip edge of the curved head portion with a wall of the channel section closes off the end of the mounting arrangement and assists in keeping dirt out of the mounting arrangement and the coiled springs. In addition it also, in part, seals off the channel section so reducing drafts through the channel section. 
     The curved head portion is resilient and tip edge of the curved head portion is arranged to resiliently abut against said wall of the channel section such that the spring support mounting is urged away from said wall. 
     The resilient abutment of the curved head and tip thereof ensures that there is a good seal between the tip and curved head portion. It also provides a secure means to locate the support mounting within the channel between the walls of the channel whilst also allowing the mounting arrangement to accommodate any manufacturing tolerance variations in the channel dimensions. 
     Wing projections extend from the front surface of the main body of the spring support mounting. A distal end of the wing projections is arranged, when the spring mounting is installed within the channel, to abut against a wall of said channel and to space the front surface of the main body of the spring support mounting from said channel wall. 
     The wing projections provide a means to laterally locate the support mounting within the channel section, whilst spacing the front surface from the channel wall such that a part of the cross section of the channel section is still unobstructed by the support mounting. 
     On the longitudinal end of the support mounting there are inter engagement means for cooperative engagement with cooperative inter engagement features on a sash shoe. The inter engagement means preferably comprise a finger extension which is arranged to be engaged within a cooperative recess. The finger extension extends from an end of the spring support mounting, and the cooperative recess is defined in an end portion of the sash shoe. 
     The inter engagement means between the sash shoe and spring support mounting locate and align the sash shoe and spring support mounting such that the sash shoe and spring support mounting can be installed within the channel as a single unit. The alignment of the sash shoe with the spring support mounting also makes the installation of the shoe within the channel easier. 
     The support means of the spring support mounting are disposed on the spring support mounting such that in use when the at least two springs recoil rapidly an outer surface of adjacent springs contact each other. 
     By arranging the support means such that the springs contact when they recoil rapidly, a braking effect is provided which slows the recoiling of the springs. 
     An end of the spring support mounting may be provided with a buffer means for absorbing, in use, an impact of a sash shoe against said end of the spring support mounting. The buffer means may comprise coil tension springs. Alternatively the buffer means comprises a finger extension which is engaged within a recess. The finger extension and recess are profiled such that as the finger extension is inserted into the recess the finger extension and recess progressively and increasingly frictionally engage each other. 
     Such a buffer means reduces damage that may be caused in the event that the sash shoe impact the spring support mounting. 
     The spring support mounting is resiliently flexible in directions extending from the front and rear surfaces. 
     Such flexibility in the support mounting allows the support mounting to be bent during installation of the support mounting within the channel section. This allows the support mounting comprising an elongate single integral component to be inserted through an industry standard channel opening which is shorter in length than the support mounting. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will now be described by way of example only with reference to the following figures in which: 
     FIG. 1 is a schematic representation of a complete sash window assembly incorporating the counterbalance spring mounting arrangement in accordance with the present invention; 
     FIG. 2 is a vertical cross sectional schematic view through the window jamb and counter balance spring mounting and in accordance with the invention, and as shown in FIG. 1; 
     FIG. 3 is a cross sectional view in a vertical direction, on section  3 — 3  of FIG.  2  through the window jamb and spring mounting of the invention; 
     FIG. 4 is a schematic perspective view of the mounting support of FIG. 2 but in isolation, showing the rear surface of the mounting body; 
     FIG. 5 is a schematic perspective view of the arrangement of springs alone as arranged in the mounting of FIG. 2; 
     FIG. 6 is a further schematic perspective view of the mounting body, similar to that of FIG. 4, but showing the facing surface of the body portion; 
     FIG. 7 is a more detailed schematic cross sectional view on arrow Y of the mounting and sash shoe ; 
     FIG. 8 is a similar view to that of FIG. 7 but showing an alternative arrangement of the mounting and sash shoe; 
     FIG. 9 is a schematic perspective view, similar to that of FIG. 4, but of an alternative embodiment of the mounting; and 
     FIG. 10 is a side elevational view showing the support mounting fit into the channel. 
    
    
     DETAILED DESCRIPTION 
     Referring to FIG. 1, a sash window  1  comprises upper  2  and lower  4  sashes which are slidably mounted within a window frame  5  such that each sash  2 , 4  can be slid vertically to open the window. The sashes  2 , 4  are disposed generally vertically and are disposed closely adjacent to each other with one sash  2  sliding behind the other  4 . The window frame  5  comprises upper  6  and lower  8  horizontal frame members and two vertical laterally spaced window jamb members  10 , 12 . The window jambs  10 , 12  have a double vertically extending channel section. Each channel section  9  of the double channel section is disposed side by side within the window jamb adjacent to a respective sash. FIG. 3 shows the profile of each channel section  9  and the two channel sections, of the double channel section within the window jamb  10 , 12  are of a similar configuration and are arranged laterally adjacent to each other to form the double channel section of the window jamb  10 , 12 . The open side of each respective channel section  9  extends vertically adjacent to the respective sides of the sashes  2 , 4 . The channel section  9  comprises rear wall  11  facing outwardly towards the sash  2 , 4  from which extend two side walls  11   a , 11   b . Short front wall portions  13  generally parallel to the rear wall  11  extend inwardly from the ends of the side walls  11   a , 11   b  towards each other to partially close off and thereby define a channel or jamb pocket  40  with an opening  42  of the channel  9  of a smaller dimension adjacent to the sash  2 , 4 . Along a small section (typically 50 mm) of the channel section  9  however the front wall members  13  are removed to provide an enlarged access opening (not shown) into the channel section  9 . Such an opening in the channel section  9  is an industry standard and is to allow a spring assembly  18   a , 18   b  and sash shoe  15   a , 15   b  to be inserted into the channel section  9 . 
     Pivot pins  14   a , 14   b , located towards the lower end of each sash  2 , 4 , extend laterally from each lateral side of each sash  2 , 4 . The pivot pins  14   a , 14   b  extend into a respective channel section  9 , through the open side and opening  42  in the channel section  9  and are pivotally engaged within a sash shoe  15   a , 15   b  which is slidably located within a respective channel section  9  of the window jamb  10 , 12 . Tilt latches  16   a , 16   b , located towards the upper part of each sash  2 , 4 , similarly extend laterally from each lateral side of each sash  2 , 4  with a tip  17  of each tilt latch  16   a , 16   b  extending into a respective channel section  9  of the window jamb  10 , 12  through the open side  42  of the channel section  9 . The pivot pins  14   a , 14   b , sash shoe  15   a , 15   b , and tilt latches  16   a , 16   b , thereby slidably locate the sashes  2 , 4  within the respective channel sections  9  of the window jambs  10 , 12  and secure the sashes  2 , 4  within the window frame  5 . 
     The tilt latches  16   a , 16   b  are arranged to be retracted, as indicated by arrow C, into the sash  2 , 4 , such that the tip  17  of the tilt latch  16   a , 16   b  can be withdrawn from the respective channel section  9  of the window jamb  10 , 12 . The sash  2 , 4  can then be pivoted about the pivot pins  14   a , 14   b , as indicated by arrow B. This allows, when the sash window is installed, access to the other side of the window for cleaning and other purposes. 
     To counter balance the weight of the sashes  2 , 4 , and assist in the vertical sliding of the of sashes  2 , 4 , a counterbalance mechanism is provided. The counter balance mechanism for each sash  2 , 4  comprises a pair of spring assemblies  18   a , 18   b  mounted in and to the window jambs  10 , 12 , and specifically within the respective jamb channel and jamb pocket  40 , on each lateral side of the sash  2 , 4 . Each spring assembly  18   a , 18   b  comprises a number of flat coiled ribbon springs  22   a , 22   b , 22   c  which are supported and mounted to the window jamb  10 , 12  via a spring assembly mounting  24 , as will be described in more detail later. The free outer ends, or tails, of each coiled spring are connected together to form a common tail  20   a , 20   b  which is drawn out from the spring assembly  18   a , 18   b  along the channel section  9  of the window jamb  10 , 12  and is connected to a respective sash shoe  15   a , 15   b . As the sash  2 , 4  slides vertically within the frame  5  the common tail  20   a , 20   b  is drawn out and retracts into the spring assembly  18   a , 18   b  with the coil springs  22   a , 22   b , 22   c  uncoiling and coiling within the spring assembly  18   a , 18   b . As a result a vertical upward force is provided by the springs  22   a , 22   b , 22   c  to counterbalance the weight of the sashes  2 , 4  and assist in the vertical sliding movement of the sashes  2 , 4 . The spring assemblies  18   a , 18   b  for each sash  2 , 4  are located at vertical positions within and along the window jamb  10 , 12  such that over the full sliding movement of the sashes  2 , 4  the springs  22   a , 22   b , 22   c  are extended to some degree and are under tension to provide a positive vertical upward force over the entire range of sliding movement of the sashes  2 , 4 . Typically therefore, and since the tails  20   a , 20   b  of the springs  22   a , 22   b , 22   c  are connected to sash shoes  15   a , 15   b  towards the lower end of each sash  2 , 4  the spring assemblies  18   a , 18   b  are generally mounted towards the middle of the window jambs  10 , 12 . 
     An individual spring assembly  18   a,  in this case for the left hand side of the lower sash  4 , is shown in more detail in FIGS. 2 to  7 . The other spring assemblies  18   a,   18   b  which are located in other respective positions in the window jambs  10 , 12  and are connected to a respective sash  2 , 4  via respective sash shoes  15   a,   15   b  are generally similar. Consequently only this spring assembly  18   a  will be described in detail. 
     The spring assembly  18   a  comprises a one piece multi spring support mounting  24  which is dimensioned to fit into and within the channel section  9  of the window jamb  12  with the width W of a main body portion  25  corresponding to the approximate width W 1  of the jamb channel  9  within which it is inserted. The spring support mounting  24  is shown on its own more clearly in FIGS. 4 and 6. The spring support mounting  24  comprises a plate like generally rectangular main body portion  25  with a front surface  21  which when installed in the jamb  12  faces outwards from the window jamb channel section  9 , and a rear surface  23  which faces towards and into the jamb channel section  9 . Integral with the main body portion  25  and extending from the rear surface  23  thereof are spring support projections  33 , 35 , 37  disposed at spaced positions along the length of the main body portion  25  of the spring support mounting  24 . 
     Three flat ribbon coiled springs  22 , lower  22   a , middle  22   b  and upper  22   c  (as considered in their final installed positions shown in FIG. 2) are arranged as shown in FIG. 5 with the outer free ends or tails of each spring connected together to form a common tail  20   a . The springs  22  are located within and on the spring support mounting  24 . The outer coiled body portions of the three flat coiled ribbon springs  22  are supported by and on the respective spring support projections  37 , 35 , 33  of the spring support mounting  24 . An axial end/side face of the coil springs  22  abuts against the rear surface  23  of the main body portion  25  of the support mounting  24 . Since the other axial end/side face of the coil springs is not enclosed by the support mounting the springs  22  can be fitted into the support very easily. Once the spring assembly  18   a , (support mounting  24  and springs  22 ) is installed into the jamb  12  and channel section  9 , the exposed axial end/side face of the spring is however then enclosed by the rear wall of the channel section which once the assembly  18   a  is installed prevents the springs  22  from sliding axially off the support projections  33 , 35 , 37 . 
     The inner free ends of the flat ribbon coil springs  22  are generally free such that as the springs  22  unwind they rotate within the spring support mounting  24  and the springs  22  provide a generally constant force as they are, in use, unwound. 
     The lower spring support projection  37  (shown to the left of FIG. 4) is of a generally rectangular section with one side of a curved/bowed profile to define a curved cooperating support surface  44  for the outer profile of the lower coil spring  22   a.    
     The centre support projection  35  comprises a pair of triangular cross section projections  34 ′, 36 ′ disposed on either side of the rear surface  23  of the main body  25 . The triangular cross section projections  34 ′, 36 ′ are arranged with a base side of the triangular section generally parallel to the longitudinal edge of the main body  25  and with an apex towards the centre of the main body  25 . The triangular projections  34 ′, 36 ′ are separated such that there is a space between the respective projections  34 ′, 36 ′ in the centre of the main body  25 . The pair of triangular projections  34 ′, 36 ′ thereby define a cradle within which the outer profile of the middle spring coil  22   b  is located and is supported. The shape of the triangular projections  34 ′, 36 ′ may preferably be profiled to cooperate with the outer profile of the spring  22   b , however exact correspondence in profile is not required to provide support for the spring  22   b . The centre support projection  35  is also adjacent to the lower coil spring  22   a  and so prevents movement of the lower spring  22   a  in an upwards direction when installed. In effect the triangular projections  34 ′, 36 ′ occupy the generally triangular space between adjacent springs  22   a , 22   b  to thereby locate these springs  22   a , 22   b  within the mounting  24  and support the springs  22   a , 22   b  when the assembly  18   a  is installed. 
     The upper support protection  34  is the same as the centre support projection  35  and the upper spring  22   c  is supported by one side surface of the respective triangular projections  34 , 36  whilst the centre spring  22   b  is also adjacent to the lower side surface of the triangular projections  34 , 36 . 
     It will be appreciated that the number of springs may be different in other embodiments of the invention depending on the counterbalance force that is required and additional, or fewer support projections can be provided. For example in FIG. 9 a support mounting of the same general type (in which like reference numerals have been used for like features) as that of FIG. 4 is shown but for mounting two springs  22 . The invention however and its advantages are though particularly and mainly applicable to multiple spring mountings which include and provide a mounting for a minimum of two springs. 
     With the triangular projections  34 , 34 ′, 36 , 36 ′ located towards the sides of the main body  25 , and by virtue of the one piece format for the support mounting  24 , the springs  22  are located relatively close together along the support structure  24 . Indeed the springs  22  can with this support mounting  24  be located such that when fully wound, and of a maximum diameter, the outer profile of adjacent springs  22   a , 22   b  and  22   b , 22   c  almost touch in the centre space between the triangular support projections  34 , 34 ′, 36 , 36 ′. As a result the overall length of the spring assembly  18   a  is considerably less than that of previous arrangements incorporating similar sized springs. In addition bowing of the support mounting  24  due to the spring  22  loads is reduced. 
     It has also been found that when coil springs  22  of this type retract and rewind quickly, for example if the load of the sash window is suddenly removed or the window is moved upward quickly, then the outer diameter of the coil spring  22  expands to a diameter greater than that of the naturally coiled spring or present under normal recoiling of the spring  22  under slower movement. With this support mounting the springs  22  can be arranged such that when they quickly retract the outer profile of the adjacent springs  22   a , 22   b  and  22   b , 22   c  contact each other and for the lower  22   a  and middle  22   b  springs they contact the adjacent triangular supports  35 , 33  for the adjacent springs  22   b , 22   c . This contact advantageously brakes the retraction of the springs  22  and slows the retraction and movement of the sash  2 , 4 . The contact between adjacent springs  22   a , 22   b  and  22   b , 22   c  provides a particularly efficient braking action since respective opposite sides of the springs  22 , which are moving in opposite directions at the point of contact, contact each other. 
     The spring support mounting  24 , as shown in FIG. 4, is preferably made of a relatively flexible plastic material, for example nylon or acetyl. The spring support mounting  24 , including integral spring support projections  37 , 35 , 33 , is fabricated as a single piece construction preferably by injection moulding. The one piece format of the support mounting  24  simplifies assembly by reducing the number of parts involved and also reduces production and assembly costs. In particular such a one piece unit is cheaper to fabricate than having to make a number of, generally different individual support mountings for the individual springs. 
     The main body  25  of the support mounting  24  is relatively thin t, typically about 1 mm. Consequently the main body portion  25 , of spring support mounting  24  is relatively flexible and can be bent to allow the spring assembly  18   a , which overall is longer than the typical 50 mm length of the access opening in the channel section  9 , to be inserted through the industry standard 50 mm access opening (not shown) in the channel section  9  of the window jamb  12 . The spring assembly  18   a  is then slid down within the channel section  9  to the correct position. The flexibility of the support mounting  24  of the present invention and one piece format, means that the support is simpler to manufacture and install into the channel section  9  of the jamb  12  as compared to the prior arrangement. This can be contrasted with prior arrangements, for example as shown in U.S. Pat. No. 5,365,638, in which the support mountings are of a rigid plastic multi piece construction with each piece of the support required to be small enough to be individually inserted through the access opening and then connected together once installed into the channel. 
     Wing projections  38  located at the edges of the main body  25  of the support mounting  24  and integral with the support mounting  24  extend from the front surface  21  of the support mounting. When the support mounting  24  is installed and fitted into the channel section  9  of the jamb  12  these wing projections  38  bear against the rear of the front walls  13  of the channel section as shown in FIG.  3 . The wing projections  38  thereby provide a means to locate the support mounting  24  within the channel section  9 . The wing projections, being fabricated from the same flexible plastic material as the rest of the support mounting  24 , are also flexible enough to bend slightly and accordingly take up any manufacturing tolerance variations in the dimensions of the channel section  9 . The wing projections  38  also space the front surface  21  of the support mounting  24 , a distance d 1  away from the channel opening  42  such that a recess is still defined in the region of the mounting  24  to allow the tip  17  of the tilt latch  16   a  which extends into the channel section  9  to remain engaged within the channel  9  as it passes over the mounting  24 . 
     The end portion of the main body  25  of the support  25  mounting  24  (when installed at the top end of the support mounting) is curved away from the rear surface of the support mounting in a direction extending from the rear surface to provide a curved head  26 , with in effect the end portion being curved longitudinally back upon the remainder of the main body of the rear surface  23  of the support mounting  24 . The curved head portion  26  curves and bows back towards the support projections  33  and closes off that end of the support mounting  24 . The tip edge  27  of the curved head is therefore disposed a distance d 2  from the front surface  21 , and the rest of the main body  25  of the support mounting  24 . Preferably this distance d 2  is slightly greater than the depth d 4  of the channel section  9  within which the support mounting  24  is fitted. When the support mounting  24  is fitted into the channel section, and since the main body  25  is relatively flexible, the curved head portion  26  is bent and straightened slightly such that the tip edge  27  is a closer distance d 3  from the rear surface  23  and rest of the main body  25  of the support mounting  24 . This allows the support mounting  24  to fit into the channel section  9 . This is shown in exaggerated form in FIG. 10 with the installed position of the curved head  26  indicated in phantom, as compared to the normal unreflected free position of the curved head portion shown in solid line. As a result of this bending of the curved head portion  26  when installed, the tip edge  27  of the curved head  26  resiliently presses against the rear wall  11  of the jamb  12  channel section  9 . This urges the front surface  21  and main body  25  of the support mounting  24  outwards and presses the wing projections  38  against the inner surface of the front walls  13  of the channel section  9 . The support mounting  24 , and in particular the top end of the mounting  24 , is thereby located relatively securely between the front  13  and rear walls  11  of and within the channel section  9  of the jamb  12 . The resilience and bending of the curved head  26  accommodates any manufacturing tolerances within the depth d 4  of the channel section  9 . The curved head portion  26  and abutment against the channel section  9  wall  11  when the support mounting  24  is installed also provides a tight seal within the channel section  9  which reduces drafts. The curved head  26  also encloses the top of the spring assembly  18   a  with the springs  22  enclosed by the curved head  26 , main body  25 , and channel section  9  walls of the jamb  12 . As a result dirt, which may interfere with the springs  22  is kept out of the assembly l 6   a  and the springs  22  are protected to some degree. 
     The curved head portion  26  also deflects the tilt latch  16   a  into the sash allowing the tilt latch  16   a  to glide over the mounting  24  as the sash  2 , 4  is moved. It will be appreciated that the tilt latch  16   a  normally extends a considerable distance into the channel section  9  to provide a secure and robust location of the top of the sash  2 , 4 . When passing over the support mounting  24  the tilt latch  16   a  is still though engaged within the channel section  9  and jamb  12  due to the spacing d 1  of the support mounting  24  from the front walls  13  by the wings  38  and due to a groove formed within the front surface  21  of the support mounting  24 . The lower end of the support mounting may also preferably be of a curved profile to allow the tilt latch  16   a  to glide over the support mounting  24  when the sash  2 , 4  and tilt latch  16   a,   16   b  are moved over the support mounting  24  from below the support mounting  24 . 
     The lateral location and positioning of the support mounting  24  within the channel section  9  itself, as opposed to the vertical position, is provided by the abutting of the wing projections  38  with the front wall  13 , the bearing of the tip edge  27  of the curved head  26  against the rear wall  11  and the width W of the support mounting  24  with the longitudinal edges abutting the side walls  11   a , 11   b  of the channel section  9 . However to locate the support mounting  24  vertically along the channel section  9  and to secure the support mounting  24  to the jamb  12  an aperture  31  is defined within the lower support projection  37 . A single mounting screw  32 , is engaged within this aperture  31  and, when the spring assembly  18   a  is fitted into the jamb  12  this secures the spring support mounting  24  as a whole to the window jamb  12 . Since the width W of the support mounting  24  corresponds generally to that W 1  of the channel section  9  the support mounting  24  is restrained from rotating about the single screw  32  fitting. The one piece format of the support mounting  24  for supporting multiple springs  22  enables the single screw  32  fitting to secure the support mounting  24  to the jamb  12 . This can be contrasted with some prior arrangements in which individual mounting structures which are individually secured to the jamb are used. The use of a single fixing screw  32  represents a simplification and reduces assembly and installation time. 
     The support mounting  24  may in alternative embodiments be secured and located vertically within the channel section  9  and jamb using pegs, spigots or catches instead of the single screw fastening described and shown. The screw fitting  32 , or other securing means may also locate the support mounting  24  against the rear wall  11  of the channel section  9  and within the channel section  9  in other embodiments, and in particular in other embodiments which do not include the curved head  26  and/or wing projections  38 . 
     The support mounting  24  also includes an integral finger extension projection  28  which extends from an end of the main body portion  25 . This finger  28  is engagable within a cooperatively shaped recess  46  within the sash shoe  15   a  to which the tails  20   a  of the springs  22  are attached and which is located beneath the spring assembly  18   a  within the channel section  9  of the window jamb  12 . This finger extension projection  28  provides a means to locate the sash shoe  15   a  relative to and with the spring assembly  18   a  such that both the shoe  15   a  and spring assembly  18   a  can be inserted into the channel section  9  together as a single unit. This aids assembly and furthermore makes it easier to slide the sash shoe  15   a  to the correct position since the spring assembly  18   a  provides a means for more easily guiding the sash shoe  15   a  within the channel section  9 . The finger  28  also, by locating the sash shoe  15   a  relative to the spring assembly  18   a , holds and locates the sash shoe  15   a  in position preventing it from twisting under pressure from the springs  22 . Such twisting of the shoe  15   a  may cause the shoe  15   a  to jam in the channel section  9  as it is being installed and consequently by preventing such twisting assembly is made easier. It will be appreciated that such twisting of the sash shoe  15   a  is not a problem once the shoe  15   a  is installed and attached to the sash  4  due to the load of the sash  4  on the shoe  15   a.    
     The finger extension  28  also provides a buffer zone to absorb the impact of the sash shoe  15   a  on the lower end of the spring support assembly  18   a . Such impact may occur in the event of excessive rapid opening and sliding of the sash  4  or if the sash  4 , and so load on the sash shoe  15   a , is suddenly removed from the shoe, for example during removal of the sash  4 . This buffer action can be further enhanced by tapering of the recess  46  and/or finger extension  28  such that they progressively engage and abut as the finger  28  is inserted into the recess  46 . The recess surface  47 , and/or finger outer profile surface  47 , could also be serrated to increase the contact friction between them which further improves the impact absorbency. In an alternative arrangement the positions of the finger  28  and recess  46  could be reversed with the sash shoe  15   a  including finger projections which engage within slots in the main body of the mounting. A suitably shaped mounting support  24 ′ is shown in FIG. 9 with slots  48  defined between projections  49  from the main body  25  and the lower mounting projection  37 . In a yet further variation, shown in FIG. 8, coil compression springs  50  are mounted on the lower end of the support mounting  24  and are arranged to axially abut against shoulders on the sash shoe  15   a . It will be appreciated that alternatively springs could be mounted on the sash shoe  15   a . In this arrangement of FIG. 8 a finger projection could also be incorporated to locate the sash shoe  15   a  and spring assembly  18   a.    
     As described the spring support mounting  24  is fixed to and within the jamb  12  and the sash shoe  15   a  is, in use, slidable within the channel section  9  and is attached to the sash  4 . This is the preferred arrangement. It will be appreciated though that this arrangement could be reversed in other embodiments and the spring support  24  could be slidably located within the channel section  9  of the jamb  12  and pivotally attached to the sash  4  with a fixed shoe. The vertical positions of the pivot pins  14   a  and tilt latches  16   a  could also be reversed with the pivot pins located at the top of the sash  4  and the tilt latch  16   a  towards the lower part of the sash  4 . 
     Along the front surface  21  of the mounting  24 , and extending longitudinally there is a spine  29  which projects from the front surface  21  and runs along the centre of the front surface  21 . This spine  29  reinforces and stiffens the support mounting  24  again assisting in preventing bowing of the support mounting. In alternative arrangements a longitudinal groove indentation could be provided and defined within the front surface  21  of the mounting  24  instead of a raised spine  29 . Such a longitudinal indentation would similarly stiffen and strengthen the support mounting. In addition a longitudinal groove would provide a track and groove within which the tip of the tilt latch could run as the tilt latch in use passes over the support mounting  24 . 
     Many other variations of the inventions will also be apparent to those skilled in the art are contemplated. Furthermore various combinations, and use of individual advantageous features of the different embodiments described may be used individually or in other combinations from those described are also contemplated.