AU648860B2 - Sash window brake - Google Patents

Description

S F Ref: 200609

AUSTRALIA

PATENTS ACT 1990 C R 0 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

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Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Alchin Long Group Pty Limited Lot 9 Redfern Street Wetherill Park New South Wales 2164

AUSTRALIA

Michael Brian Alchin Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Sash Window Brake ASSOCIATED PROVISIONAL APPLICATION DETAILS [31] Application No(s) [33] Country PK455, AU [32] Application Date 11 February 1991 The following statement is a full description of this invention, including the best method of performing it known to me/us:- 8 -2 SASH NINDON BRAKE FIELD OF THE INVENTION The following invention relates to sash windows and more particularly, though not exclusively to a brake system for sash windows.

BACKGROUND ART Sash windows consist of a window jamb including vertical members which slideably receive a window panel usually including a glass sheet. A balance system is often provided for the window so that the same may be retained in a raised position. It is disadvantageous that such systems are not always reliable, are complex and generally expensive. For example, one such known sash window balance assembly comprises a generally U-shaped main frame which receives therein an inner wedge member. The main frame is characterized by opposing arms, each of which bears an outwardly facing friction pad. Each of the friction pads is adapted to press against an inner edge of a track or groove in which the sash is vertically slideable.

It is a particular disadvantage of this assembly that the main frame must be constructed from a material which not only provides good resilience but which also displays sufficient friction characteristics for the purpose of braking. Clearly, compromises must be made when selecting a material.

Furthermore, due to the integral design of the friction pads with the main frame, the opposing arms pivot outwardly leading to uneven wear of the •friction pads.

OBJECT OF THE INVENTION It is the object of the present invention to overcome or 25 substantially ameliorate at least one of the above disadvantages.

SUMMARY OF THE INVENTION There is disclosed herein a sash window balance assembly comprising; a carriage frame having opposing co-extensive spaced arms, a pair of friction pads, each movably supported on the carriage and 30 guided by a respective arm, and wedge means positioned between the pads such that upon movement of the wedge means, the friction pads move outwardly in response thereto.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings, wherein: Fig. 1 is a schematic elevational view of an assembled sash window brake assembly, 4C 821 3 Figs. 2(b) and 2(c) are schematic plan, side elevational and end elevational views respectively of a main frame which forms part of the assembly of Fig. 1, Figs. 3(b) and 3(c) are schematic plan, end elevational and side elevational views respectively of a center wedge which forms part of the assembly of Fig. 1, and Figs. 4(c) and 4(d) are schematic plan, end elevational, cross-sectional end elevational and side elevational views respectively of a friction pad which forms part of the assembly of Fig. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT INCLUDING BEST MODE OF CARRYING OUT THE INVENTION In Fig. 1 of the accompanying drawings, there is schematically depicted a window brake assembly 1 which comprises a main or carriage frame 2 and a wedge member 3. As shown in more detail in Figs. 2(b) 15 and 2(c) the main frame 2 includes generally symmetrical opposing arms connected by a base 6. The upper portion of each arm 5 terminates in a guide bar 7. Guide bar 7 is adapted to define a passage and guide friction pads 4 therepast. Also attached to each of opposing arms 5 is a guide pin 8. Guide pin 8 is adap,.d to be received within slot 9, a pair of which are provided in each of friction pads 4.

Friction pads 4 as depicted in Fig. 4 comprise a friction surface on each of a pair of laterally opposed brake sections 11. Brake sections 11 are separated by a separating plate 12. It should be appreciated that each of the brake sections of friction pads 4 is to be located on an opposing side of opposing arms 5 of the main frame 2. Each brake section 11 also includes an inward and downwardly facing wedge portion 13.

The wedge member 3 is slideably received within the main frame 2.

Wedge member 3 preferably includes opposed upwardly facing wedges or ramps 14 which slideably contact the downwardly facing wedge portions 13 of friction pads 4. The top portion of the wedge member 3 comprises a slot or other retention means for retaining the lower end of the balance spring of the window apparatus, as will be explained in more detail.

As an optional feature, a resilient spring or other biassing means may be located between the lower end of wedge member 3 and base 6 of main frame 2. Such a resilient spring would exert a compressive force which tends to drive the wedge member 3 upward, thereby causing friction pads 4 to move apart and thus engage with the rails of the window apparatus.

TMS/29821 -4- As shown more clearly in Fig, 2, the main frame 2 further includes a flange 16 having a slot 17 formed therethrough. Flange 16 and slot 17 serve as a means by which the brake is fixed to the bottom portion of a sliding sash window. Typically, a bolt extending through slot 17 attaches the flange to the sash window.

It will be understood that the jamb frame which receives the sash includes a track or groove in which the sash is vertically slideable. An elongated spring is suspended within the groove or track from the top of the track. The bottom of the elongated spring attaches to the retaining slot 15 of the wedge member 3. The tension in this elongated spring aids in retaining the sash panel In a desired position relative to the jamb frame. The elongated spring is in a condition of maximum tension when the sash is fully lowered. The tension exerted by the elongated spring directs the wedge member 3 upwardly, thus tending to separate the friction pads 4, 0000 15 which in turn creates a frictional engagement with the groove or track, thus tending to maintain the sash in a fixed position. In the raised position the elongated spring is in a condition of minimum tension S whereupon the upwardly directed force on the wedge Is at a minimum. It is *00000 S* for this purpose that the coil spring (not shown) is provided between base 6 of main frame 2 and wedge member 3. Such a spring would tend to drive the wedge member 3 upwardly, creating a braking action, should the tension force exerted by the elongated spring be insufficient.

"It will be appreciated that the brake mechanism disclosed by the Spreseni invention is, in a sense, self sizing. By this it is meant that the braking force exerted by the opposed friction pads 4 against the groove o or track is proportional to the tension in the elongated spring which supports the sash. Thus, in a large member where a large spring balances a to large sash, a larger tensile force operates on the wedge member 3, which in "turn creates a large braking force by the friction pads 4. In this way, one size brake may be used in a number of different window sizes and will exert a suitable braking force in each different window size.

Glass filled "NYLON 66" is considered a suitable material for the construction of frame and although such a material might also be suitable for use in friction pads 4, other materials displaying superior frictional characteristics are envisaged, particularly as the pads are formed separately to the frame 2.

TMS/29821 It should be appreciated that modifications and alterations obvious to those skilled in the art are not to be considered as beyond the scope of the present invention. For example, rather than providing a compressive spring between base 6 of main frame 2 and wedge member 3, such a spring may be provided between opposing pairs of friction pads 4 so as to bias the friction pads 4 outwardly thus creating a braking effect.

In the above described embodiment the pads 4, by being movably mounted on the arms 5, maintain good contact with the friction surfaces independent of their movement due to the wedge member 3. Also by forming the pads 4 separately, the frame 2 can be formed of stronger material, which would not be suitable for the pads 4.

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Claims (6)

1. A sash window balance assembly comprising; a carriage frame having opposing co-extensive spaced arms, a pair of friction pads, each movably supported on the carriage and guided by a respective arm, and wedge means positioned between the pads such that upon movement of the wedge means, the friction pads move outwardly in response thereto.

2. The assembly of claim 1 wherein each arm comprises a guide bar to guide the respective friction pad.

3. The assembly of claim 1 or claim 2 wherein each arm further comprises a guide pin and wherein each friction pad comprises a slot into which said guide pin extends.

4. The assembly of any one of the proceeding claims wherein each friction pad comprises a pair of laterally opposed brake sections each located on an opposing side of one of said arms and separated by a plate.

The assembly of any one of the preceding claims wherein the fric*ion pads are wedge shaped so as to co-operate with the wedge means, which wedge means being tensioned to a window frame by way of a spring element.

6. A sash window balance assembly substantially as hereinbefore described with reference to the accompanying drawings. SDATED this SEVENTEENTH day of FEBRUARY 1994 Alchin Long Group Pty Limited Patent Attorneys for the Applicant SPRUSON FERGUSON 0* 0 RLF/29821 SASH WINDON BRAKE ABSTRACT OF THE DISCLOSURE A brake system for sash windows comprises a brake assembly having a carriage frame and a wedge member The carriage frame (2) include generally symmetrical opposing arms connected by a base The upper portion of each arm terminates in a guide bar Guide bar is adapted to define a passage and guide friction pads therepast. Also attached to each of opposing arms is a guide pin which is adapted to be received within slot a pair of which are provided in each friction pad The window jamb frame which receives the sash includes a track or groove in which the sash is vertically slidable. An elongate spring is suspended within the groove or track from the top of the track. The bottom of the elongate spring attaches to the wedge member (3) j*k** S* so as to bias the wedge member upwardly and force friction pads for 15 outwardly against the groove in the jamb frame. S Fig. 1 a 0* 4 0*0 oc J oo TMS/29821