GB2544986A

GB2544986A - Sash restrictor

Info

Publication number: GB2544986A
Application number: GB1521202.0A
Authority: GB
Inventors: Sehdeva Richard
Original assignee: Era Home Security Ltd
Current assignee: Era Home Security Ltd
Priority date: 2015-12-01
Filing date: 2015-12-01
Publication date: 2017-06-07
Also published as: GB201521202D0

Abstract

The sash restrictor 6 has a frame attachment member 16, engaged with a track 10 of a window jamb, pivotally connected to an arm 14 at end 22 by a first connection means 24, the other end 26 of the arm 14 is pivotally connected to a sash attachment member 18 engaging a channel 20 of a window sash 4 by a second connection means 28. Preferably, a pair of restrictors 6 are provided for a sash window having a pair of jambs, each having a track 10 in which the frame attachment member 16 can slide. The connection means 24,28 may comprise a friction fit sleeve around a fastener with a washer located between, and in contact with both, the arm 14 and the respective attachment member 16,18. Preferably, the sash attachment member is fixed in the channel, and has a fixed friction block with a recess in contact with an outer circumferential surface of the respective washer. The fasteners may be rivets and the washers made of compressible plastic providing sufficient axial and/or radial frictional forces acting between surfaces of the parts to control the rate of opening, and support weight of the sash in an open position.

Description

Sash Restrictor

FIELD OF THE INVENTION

The present invention relates to a sash restrictor for restricting the tilting movement of a window sash relative to a frame. More particularly the invention relates to a sash restrictor for restricting the tilting movement of a vertically sliding window sash relative to a frame.

BACKGROUND TO THE INVENTION

Sash windows are popular due to their traditional appearance and may be required to be installed in period properties in conservation areas. Traditional sash windows comprise a frame attached to the window opening by means of a pair of jambs. Two sashes slide vertically, one in front of the other, within the grooves of a liner located in the jambs. The lower sash is typically located in the innermost groove of the liner and is slid upwards during opening of the window. The upper sash is typically located in the outer groove and can be slid downwards to improve ventilation throughout the room. The weight of each sash was traditionally supported by means of counterbalancing weights, which slide up and down on a cord concealed within the window frame. In modern designs, the weight of the sashes can be supported instead by spring balances. The spring balances may be provided with tilt attachments and pivot shoes to enable either or both sashes to be tilted inwardly to aid in the cleaning of the window pane for example. The sashes are typically tilted about a horizontal axis along their lower edges. The pivot shoes may provide a limited frictional resistance to control the tilting of the sash.

In addition to the spring balances, sash restrictors may be provided to support the weight of the sashes, particularly when they are in a tilted position. Generally, each sash is supported by a pair of sash restrictors, with a sash restrictor being provided at each side of the sash. Such sash restrictors typically comprise at least one arm, one end of which is pivotally connected to the frame and the other end of which is pivotally connected to the sash. At least one of the connections to the frame or the sash may be via a slider which is vertically slidable along the frame or the sash. The sash restrictors also help to limit the tilting angle of the sashes. The tilting angle is limited by the length of the arm(s) and the distance that the slider(s) can travel along the frame or the sash. Stops (or stoppers) may be provided in the frame jambs and/or sash channels to limit the distance the slider(s) can travel.

Heavy window sashes, such as those of a large size and/or those containing double or triple glazed window panes for example, inevitably place a large load on the sash restrictor when they are in the tilted position. In addition, it is possible that a user will find the weight of such heavy sashes difficult to support whilst the sash is being tilted open. Thus there is an increased possibility for heavy sashes to ‘fall’ or be ‘dropped’ whilst being tilted open. This causes a sudden increase in load on the sash restrictor. An increase in load on the sash restrictor could also feasibly be caused by a sudden external force being applied to the sash whilst it is tilted open, such as, for example, a gust of wind. These situations may cause a gradual or sudden failure of the sash restrictor connections and potential injury to the user. Some known sash restrictors may comprise springs or buffers as part of the sash connection, which absorb the increase in loading force on the sash restrictor, from the weight of the sash, as the sash is tilted and/or held open.

The present invention seeks to provide an improved sash restrictor or to overcome or ameliorate at least one of the problems of the prior art, or provide a useful alternative.

SUMMARY OF THE INVENTION

According to the present invention, there is provided a sash restrictor for restricting the tilting movement of a window sash relative to a vertical plane of a frame. The sash restrictor may include an arm, which may have a first end and a second end. The sash restrictor may be a single arm sash restrictor. The sash restrictor may include a frame attachment member, which may be configured for engagement with a track of a window jamb. The sash restrictor may include a first connection means, which may pivotally connect the first end of the arm to the frame attachment member. The sash restrictor may include a sash attachment member, which may be configured for engagement in a channel of a window sash. The sash restrictor may include a second connection means, which may pivotally connect the second end of the arm to the sash attachment member. The sash restrictor may be configured to restrict the movement of the window sash relative to the vertical plane of the frame by pivotal frictional forces which resist relative movement between at least one of the respective attachment members and the arm as a load on the sash restrictor increases.

The load on the sash restrictor increases as the window sash tilts more from the vertical orientation. It will be appreciated that the window sash may be in a tilted position, for example, during the action of opening and/or closing the window sash and also when the window sash is supported in a desired tilted open position (e.g. partially or fully open).

In some embodiments, the movement of the window sash may be restricted by the pivotal frictional forces providing sufficient resistance to control the rate of opening of the window sash. This prevents the sash from being dropped or falling whilst it is being tilted open and so reduces the risk of damage occurring to the sash restrictor.

Alternatively, or in addition, the movement of the window sash may be restricted by the pivotal frictional forces providing sufficient resistance to support the weight of the sash in a tilted open position. The weight of the sash may be supported in a partially tilted or in a fully tilted position. When the sash is in a fully or partially tilted position, it will be appreciated that the weight of the sash may, in addition, be supported by the arm.

In some embodiments, the sash restrictor may be configured to restrict the tilting movement of a window sash weighing at least 10, 20, 25, 30, 35, 40 or 45 kg. In some embodiments, the sash restrictor may be configured to restrict the tilting movement of a window sash weighing no more than 50, 45 or 40 kg. In some embodiments, the sash restrictor may be configured to restrict the tilting movement of a window sash weighing no more than 50 kg.

An advantage of the sash restrictor of the present invention is the pivotal friction forces enable the movement of a heavy window sash (e.g. a window sash weighing more than 35 kg) relative to the vertical plane of the frame, to be restricted using a sash restrictor comprising only one arm. In particular, a heavy window sash may be supported in a partially or fully tilted open position using a sash restrictor comprising only one arm. Since the sash restrictor comprises only one arm, this, in turn, may allow the sash restrictor to be more readily and cheaply manufactured.

In some embodiments, the pivotal frictional forces may comprise radial frictional forces which act between at least one of: respective circumferential surfaces of the first connection means; respective circumferential surfaces of the first connection means and the frame attachment member; respective circumferential surfaces of the first connection means and the first end of the arm; respective circumferential surfaces of the second connection means; respective circumferential surfaces of the second connection means and the sash attachment member; respective circumferential surfaces of the second connection means and the second end of the arm.

In some embodiments, the pivotal frictional forces may comprise radial frictional forces which act between at least one of: respective circumferential surfaces of one or both connection means; one or both connection means and the respective attachment member; and one or both connection means and the respective end of the arm.

In some embodiments, the pivotal frictional forces may comprise axial frictional forces which act between at least one of: opposing faces of the first connection means and the frame attachment member; opposing faces of the first connection means and the first end of the arm; opposing faces of the second connection means and the sash attachment member; and opposing faces of the second connection means and the second end of the arm.

In some embodiments, the pivotal frictional forces may comprise axial frictional forces which act between at least one of: respective opposing faces of one or both connection means and the respective attachment member; and one or both connection means and the respective end of the arm.

In some embodiments, the pivotal frictional forces may comprise the radial frictional forces and the axial frictional forces.

The arm may be elongate. In some embodiments the arm may be made of a metal or an alloy. For example, the arm may be made from steel, e g. stainless steel.

In some embodiments the length of the arm may be approximately 95, 90, 80, 85, 70, 65, 60, 55 or 50% of the height of the window sash. For example, the arm may be from 400mm to 800mm. In some embodiments the arm may be from 470mm to 600mm long.

In some embodiments, the frame attachment member may be configured to be slidably engaged with the track.

In some embodiments, the sash attachment member may be configured to be fixedly engaged in the channel of the window sash. In some embodiments, the sash attachment member may be configured to be fixedly engaged in a position along the channel, which is closer to a top rail of the sash than a bottom rail of the sash. In some embodiments, the sash attachment member may be configured to be fixedly engaged in a position along the channel substantially adjacent to a top rail of the sash.

It will be appreciated that the maximum tilting movement of the sash relative to the vertical plane of the frame (i.e. the maximum tilting angle) is limited by the length of the arm and the position along the channel at which the sash attachment member is fixed.

In some embodiments, the tilting angle of the sash relative to the vertical plane of the frame is no more than 40, 45 or 50 degrees.

The first connection means may comprise a first fastener, a first sleeve and a first washer.

The first fastener may be a rivet.

The first sleeve may have a friction fit around the first fastener. In such embodiments, radial frictional forces may act between an outer circumferential surface of the first fastener and an inner circumferential surface of the first sleeve as the load on the sash restrictor increases. In addition or alternatively, axial frictional forces may act between opposing faces of the first fastener and the first sleeve as the load on the sash restrictor increases.

The first sleeve may cover or partially cover the first fastener.

The first fastener may be a first rivet and the first sleeve may cover or partially cover the first rivet. It will be understood that in either set of embodiments, the first sleeve covers at least a cylindrical shaft of the first rivet. Therefore, radial frictional forces may act between an outer circumferential surface of the cylindrical shaft of the first rivet and an inner circumferential surface of the first sleeve as the load on the sash restrictor increases.

In embodiments where the first sleeve covers the first rivet, the first sleeve may completely cover a head of the first rivet in addition to the cylindrical shaft of the first rivet. In embodiments where the first sleeve partially covers the first rivet, the first sleeve may partially cover a head of the first rivet in addition to the cylindrical shaft of the first rivet. It will be understood that in either set of embodiments, the first sleeve will cover at least an outer circumferential surface of the head of the first rivet. Thus, radial frictional forces may act between the outer circumferential surface of the head of the first rivet and an inner circumferential surface of the first sleeve as the load on the sash restrictor increases.

In embodiments in which an outer face of the head is covered or partially covered by the first sleeve, in addition to the outer circumferential surface of the head, axial frictional forces may act between opposing faces of the head of the first rivet and the first sleeve as the load on the sash restrictor increases.

The first fastener and the first sleeve may extend through an aperture in the frame attachment member. Thus, radial frictional forces may act between an edge of the aperture and an outer circumferential surface of the first sleeve as the load on the sash restrictor increases.

The first washer may have a friction fit around the first sleeve. Thus, radial frictional forces may act between an inner circumferential surface of the first washer and the outer circumferential surface of the first sleeve as the load on the sash restrictor increases.

The first end of the arm may be provided with a first hole and the first hole may have a friction fit around the first sleeve. Radial frictional forces may act between an edge of the first hole and the outer circumferential surface of the first sleeve as the load on the sash restrictor increases.

The first washer may be located between the frame attachment member and the first end of the arm. A first face of the first washer may be in contact with the frame attachment member. Axial frictional forces may act between the first face of the first washer and the frame attachment member (i.e. the respective opposing faces) as the load on the sash restrictor increases. A second face of the first washer may be in contact with the first end of the arm. The second face may be at least partially recessed in a first groove in the first end of the arm. Axial frictional forces may act between the second face of the first washer and the first end of the arm (i.e. the respective opposing faces) as the load on the sash restrictor increases.

Radial frictional forces may act between at least one circumferential surface of the first washer and the first groove.

The first washer may be compressible. This may increase the axial frictional forces acting between at least one of: the first face of the first washer and the frame attachment member; and the second face of the first washer and the first end of the arm.

In some embodiments the first end of the arm may be partially covered in a plastics material. This may increase the axial frictional forces acting between the second face of the first washer and the first end of the arm.

The second connection means may comprise a second fastener, a second sleeve and a second washer.

The second fastener may be a rivet.

The second sleeve may have a friction fit around the second fastener. In such embodiments, radial frictional forces may act between an outer circumferential surface of the second fastener and an inner circumferential surface of the second sleeve as the load on the sash restrictor increases. In addition or alternatively, axial frictional forces may act between opposing faces of the second fastener and the second sleeve as the load on the sash restrictor increases.

The second sleeve may cover or partially cover the second fastener.

The second fastener may be a second rivet and the second sleeve may cover or partially cover the second rivet. It will be understood that in either set of embodiments, the second sleeve covers at least a cylindrical shaft of the second rivet. Therefore, radial frictional forces may act between an outer circumferential surface of the cylindrical shaft of the second rivet and an inner circumferential surface of the second sleeve as the load on the sash restrictor increases.

When the second sleeve covers the first rivet, the second sleeve may completely cover a head of the second rivet in addition to the cylindrical shaft of the second rivet. When the second sleeve partially covers the second rivet, the second sleeve may partially cover a head of the second rivet in addition to the cylindrical shaft of the second rivet. It will be understood that in either set of embodiments, the second sleeve will cover at least an outer circumferential surface of the head of the second rivet. Thus, radial frictional forces may act between the outer circumferential surface of the head of the second rivet and an inner circumferential surface of the second sleeve as the load on the sash restrictor increases.

In embodiments in which an outer face of the head is covered or partially covered by the second sleeve, in addition to the outer circumferential surface of the head, axial frictional forces may act between opposing faces of the head of the second rivet and the second sleeve as the load on the sash restrictor increases.

The second fastener and the second sleeve may extend through an aperture in the sash attachment member. Thus, radial frictional forces may act between an edge of the aperture and an outer circumferential surface of the second sleeve as the load on the sash restrictor increases.

The second washer may have a friction fit around the second sleeve. Radial frictional forces may act between an inner circumferential surface of the second washer and an outer circumferential surface of the second sleeve as the load on the sash restrictor increases.

The second end of the arm may be provided with a second hole and the second hole may have a friction fit over the second sleeve. Radial frictional forces may act between an edge of the second hole and an outer circumferential surface of the second sleeve as the load on the sash restrictor increases.

The second washer may be located between the sash attachment member and the second end of the arm. A first face of the second washer may be in contact with the sash attachment member. Axial frictional forces may act between the first face of the second washer and the sash attachment member (i.e. the respective opposing faces) as the load on the sash restrictor increases. A second face of the second washer may be in contact with the second end of the arm. The second face may be at least partially recessed in a second groove in the second end of the arm. Axial frictional forces may act between the second face of the second washer and the second end of the arm (i.e. the respective opposing faces) as the load on the sash restrictor increases.

Radial frictional forces may act between at least one circumferential surface of the second washer and the second groove.

The second washer may be compressible. This may increase the axial frictional forces acting between at least one of: the first face of the second washer and the sash attachment member; and the second face of the second washer and the second end of the arm.

In some embodiments the second end of the arm may be partially covered in a plastics material. This may increase the axial frictional forces acting between the second face of the second washer and the second end of the arm.

The first and/or second sleeves may be made of a plastics material. The first and second sleeves may be made of the same or different plastics material.

The first and/or second washers may be made of a plastics material. The first and second washers may be made of the same or different plastics material. In some embodiments, the first and/or second washers may comprise nylon (e.g. nylon 66) or an acetal polymer.

It will be appreciated that the amount of pivotal friction produced as the load on the sash restrictor is increased, depends on, for example the material of the first and/or second connection means, and in particular those of the first and/or second sleeves and of the first and/or second washers.

The second fastener, the second sleeve and the second washer may be longer than the corresponding first fastener, first sleeve and first washer. Since the sash attachment member is configured to be fixedly engaged in the channel, this may be necessary to compensate for the depth of the channel.

It will also be appreciated that the amount of pivotal friction produced as the load on the sash restrictor is increased, depends on, for example, the dimensions of the first and/or second connection means, and in particular those of the first and/or second sleeves and of the first and/or second washers. For example, sleeves and washers of longer length and/or diameter will have a larger circumferential surface area for contact with the surfaces of adjacent components and thus may produce more radial friction. Washers of longer length may provide more compression between opposing facing surfaces and thus may also produce more axial friction.

First and/or second connection means which produce greater amounts of pivotal friction (due to the material and/or dimensions) may be more suitable for restricting the movement of heavier window sashes. In some embodiments, the first and/or second connection means may be colour coded to indicate the maximum weight of the window sash that the first and/or second connection means can be used in conjunction with.

The sash attachment member may further comprise a friction block.

The friction block may be fixed to the sash attachment member. The friction block may be fixed to the sash attachment member by a third fastener. The third fastener may be a third rivet. It will be understood that when the sash attachment member is fixedly attached in the channel of the window sash, the friction block resides substantially within the channel. Otherwise, the friction block would protrude from the channel and the window sash would be prevented from closing.

The friction block may be in contact with an outer circumferential surface of the second washer. In such embodiments, it will be appreciated that the friction block is fixed to the sash attachment member substantially adjacent to the second connection means.

The friction block may be configured to provide pivotal frictional forces which resist the relative movement between the sash attachment member and the arm as the load on the sash restrictor increases. The pivotal frictional forces may be radial frictional forces which act between the friction block and the outer circumferential surface of the second washer. An advantage of the friction block is that the frictional forces restricting the relative movement are increased. This, in turn, assists in supporting heavy sash windows using a sash restrictor comprising only one arm.

The friction block may comprise a recess. In some embodiments, the recess may be hemispherical. It will be appreciated that the shape of the recess preferably corresponds to the shape of the second washer.

The recess may have a radius which is co-radial to a radius of the second washer.

The recess may be in contact with an outer circumferential surface of the second washer. In such embodiments, the pivotal frictional forces may be radial frictional forces which act between the recess and the outer circumferential surface of the second washer.

In some embodiments, an edge of the second end of the arm may be in contact with the recess. The pivotal frictional forces may be radial frictional forces acting between the recess and the edge of the second end of the arm.

In some embodiments, the outer circumferential surface of the second washer and the edge of the second end of the arm may be in contact with the recess.

In embodiments where the second end of the arm is partially covered by a plastics material, this may increase the radial frictional forces acting between the recess and the edge of the second end of the arm.

The sash restrictor of the present invention comprises few component parts and in particular, few complex component parts, especially in comparison with known devices which may comprise multiple arms and/or springs or buffers. An advantage of the present invention is therefore that the restrictor can be manufactured readily and cheaply. In addition, the friction technology in the sash restrictor of the present invention is compact since the frictional forces are created around pivot points. The sash restrictor of the present invention therefore looks similar to a standard tilt restrictor.

According to a second aspect of the present invention there is provided a sash window assembly for restricting the tilting movement of a window sash relative to a vertical plane of a frame. The sash window assembly may include a frame, which may include a head, a sill and a pair of jambs, each jamb having a track defined therein. The sash window assembly may include at least one window sash. The or each sash may comprise a pair of channels and be vertically slidable in relation to the frame and tiltable with respect to a vertical plane of the frame. The sash window assembly may include at least one sash restrictor according to the first aspect of the invention. The or each frame attachment member is engaged with the track of a respective jamb and the or each sash attachment member is engaged in the channel of a respective window sash.

The sash window assembly may comprise a pair of sash restrictors for each window sash.

Comments made in relation to the first aspect of the invention also apply to the second aspect of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will now be described by way of example only with reference to the accompanying figures in which:

Figures 1A to 1C show side views of a sash window assembly and a sash restrictor in accordance with an embodiment of the present invention with a sash in a tilted position, a partially tilted position and a closed position;

Figure 2 shows an exploded view of a sash restrictor in accordance with an embodiment of the present invention;

Figure 3 shows a cross section through an embodiment of a first end of a sash restrictor; and

Figure 4 shows a cross section through an embodiment of a second end of a sash restrictor.

With reference to Figures 1A to 1C, there is illustrated a sash window assembly and a sash restrictor according to an embodiment of the present invention. The sash window assembly (2) comprises a frame, a sash (4) and a sash restrictor (6). In some embodiments, the sash (4) may be supported by a pair of sash restrictors (6), one at each side of the sash (4). The frame is adapted to be fitted into an opening in a building and comprises a head, a sill and a pair of jambs (8). The jambs (8) are disposed vertically, one at each end of the frame to connect the head to the sill. Each of the jambs (8) are provided with a liner, which has an inner track (10) and an outer track (12) separated by a parting bead.

The sash (4) is shown as the lower, innermost sash. Each side of the bottom rail of the sash (4) is slidably attached to a respective inner track (10), for example, by means of a standard foot attachment and a pivot shoe (13). The upper rail of the sash (4) is slidably attached to a respective inner track (10) at both sides by means of catches (not shown). Thus, the sash (4) is vertically slidable in relation to the frame. The pivot shoe (13) is provided to enable the sash (4) to be tiltable with respect to the vertical plane of the frame, when the catches are retracted from within their respective inner tracks (10).

The tiltable movement of the sash (4) with respect to the vertical plane of the frame is restricted by the sash restrictor (6). The sash restrictor (6) comprises an arm (14), a frame attachment member (16) and a sash attachment member (18). The frame attachment member (16) is slidably engaged with the inner track (10). The sash attachment member (18) is fixed, by means of screws (19) for example, in a channel (20) in the sash (4). The arm (14) has a first end (22) which is pivotally attached to the frame attachment member (16) by a first connection means (24). A second end (26) of the arm (14) is pivotally attached to the sash attachment member (18) by a second connection means (28).

Referring now to Figure 2, the sash restrictor (6) is shown in more detail. The frame attachment member (16) is shaped to be slidably retained within the inner track (10) of the window jamb. The first connection means (24) comprises a first rivet (30), a first sleeve (32) and a first washer (34). The first sleeve (32) has a friction fit around the first rivet (30) and partially covers the first rivet (30). The first sleeve (32) covers a cylindrical shaft (33) of the first rivet (30) and an outer circumferential portion of a rivet head (35). The inner circumferential surface of the first sleeve (32) is thus in contact with the outer circumferential surface of the cylindrical shaft (33) and the outer circumferential surface of the rivet head (35) and radial friction may be provided between either or both of these surfaces as the sash restrictor (6) is loaded.

The first rivet (30) and the first sleeve (32) extend through an aperture (36) in the frame attachment member (16). The first washer (34) and a hole (38) in the first end (22) of the arm (14) have a friction fit around the first sleeve (32) to pivotally attach the first end (22) of the arm (14) to the frame attachment member (16). Radial friction may therefore be generated between the surfaces of the inner circumference of the hole (38) (i.e. the edge of the hole) and the outer circumference of the first sleeve (32) as the load on the sash restrictor is increased.

Similarly, radial friction may be generated between the inner circumferential surface of the first washer (34) and the outer circumferential surface of the first sleeve (32) as the sash restrictor is loaded. In addition, a first face of the first washer (34) is in contact with the frame attachment member (16) and a second face is in contact with the first end (22) of the arm (14). This provides axial friction between the opposing faces of the frame attachment member (16) and the first face of the first washer (34) and/or between the second face of the first washer (34) and the first end (22) of the arm (14). The first washer (34) may add compression between the frame attachment member (16) and the first end (22) of the arm (14) to increase the axial frictional forces.

The first washer (34) is shaped so that the second face is at least partially recessed within a first groove (40) in the first end (22) of the arm (14) (for example, the second face may be bowl-shaped). Therefore, radial friction may also be generated between the outer circumferential surface of the first washer (34) and the groove (40) in the first end (22) of the arm (14).

The sash attachment member (18) is fixedly attached in a channel (20) in the sash (4). The sash attachment member (18) may, for example, be fixed by means of screws (19) through bores (42). Fixing of the sash attachment member (18) to the sash (4), in combination with the length of the arm (14), sets the maximum tilt angle of the sash (4). For example, for heavy sashes the maximum tilt angle is preferably 40 degrees from the vertical.

The second connection means (28) comprises a second rivet (44), a second sleeve (46) and a second washer (48). The second sleeve (46) has a friction fit around the second rivet (44). The second sleeve (46) partially covers the second rivet (44). The second sleeve (46) covers a cylindrical shaft (43) of the second rivet (44) and an outer circumferential portion of a rivet head (45). The second rivet (44) and the second sleeve (32) extend through an aperture (50) in the sash attachment member (18) and the second washer (48) and a hole (52) in the second end (26) of the arm (14) have a friction fit around the second sleeve (46) to pivotally attach the second end (26) of the arm (14) to the sash attachment member (18). A first face of the second washer (48) is in contact with the sash attachment member (18) and a second face is in contact with the second end (26) of the arm (14). The second washer (48) may add compression between the sash attachment member (18) and the second end (26) of the arm (14) to increase the axial frictional forces. In some embodiments, the second washer (48) may be shaped so that the second face is at least partially recessed within a second groove in the second end (26) of the arm (14) (for example, the second face may be bowlshaped).

Therefore, in a similar manner to the first connection means (24) described above, radial frictional forces may be generated between at least one of: inner circumferential surface of the second sleeve (48) and the outer circumferential surface of the cylindrical shaft (43) of the second rivet (44); the surfaces of the inner circumference of the hole (52) (i.e. the edge of the hole) and the outer circumference of the second sleeve (46); the inner circumferential surface of the second washer (48) and the outer circumferential surface of the second sleeve (46); the outer circumferential surface of the second washer (48) and the groove in the second end (26) of the arm (14) as the load on the sash restrictor increases. Axial friction forces may be generated between at least one of: the opposing faces of the sash attachment member (18) and the first face of the second washer (48); and the second face of the second washer (48) and the second end (26) of the arm (14) as the load on the sash restrictor increases.

The sash attachment member (18) is also provided with a friction block (54). The friction block (54) is attached to the sash attachment member (18) through an aperture (56) by, for example, a third rivet (58). The friction block (54) resides substantially within the channel (20) in the sash (4) and sits substantially flush with the second end (26) of the arm (14) so that it does not substantially project out from the channel and prevent the window sash (4) from adopting a closed (i.e. non-tilted) position. The friction block (54) has a recess (60), which in this embodiment, is hemispherical. The hemispherical recess (60) has a radius which is co-radial to an outer radius of the second washer (48). The friction block (54) is fixed in position on the sash attachment member (18) so that the outer circumferential surface of the second washer (48) is in contact with the hemispherical recess (60). The edge of the second end (26) of the arm (14) is also in contact with the recess (60) of the friction block (54) and notches (62) are provided to enable the second end (26) of the arm (14) to pivot with respect to the friction block (54). Thus, as the sash restrictor is loaded during tilting of the window sash (4), radial friction is generated between the hemispherical recess (60) and the outer circumferential surface of the second washer (48). Radial friction may also be generated between the hemispherical recess and the edge of the second end (26) of the arm (14).

The second rivet (44), the second sleeve (46) and the second washer (48) are each longer than the corresponding first rivet (30), first sleeve (32) and first washer (34). This is to compensate for the depth of the channel (20). The depth of the friction block (54) and the hemispherical recess (60) is also determined by the depth of the channel (20) and may substantially correspond to the length of the second washer (48).

The choice of material for the first and/or second sleeves (32, 46) and the first and/or second washers (34, 48) is dependent on the frictional force required to support the weight of the window sash. The first and second rivet covers (32, 46) and the first and second washers (34, 48) are typically a plastics material. The sleeve and the washer are preferably made from a nylon material, e.g. nylon 66. The arm is preferably a steel alloy, e.g. stainless steel.

The dimensions of the first and/or second rivets (30, 44), the first and/or second sleeves (32, 46) and the first and/or second washers (34, 48) may be chosen depending on the weight of the window sash. It will be appreciated that larger components may create more friction between adjacent circumferential surfaces and/or opposing faces and so may be more suitable for supporting heavier window sashes.

When the sash (4) is tilted inwardly from its closed position shown in Figure 1C, by releasing the catches on the upper rail of the sash (4), the frame attachment member (16) slides vertically upwards along the respective inner track (10) of the frame jamb. The bottom rail of the sash (4) remains in engagement with the respective inner track (10) and pivots around a horizontal axis passing through the bottom rail. The first and second ends of the arm (14) pivot around the respective first and second connection means so that the arm (14) extends out of the vertical plane of the frame. The extent of opening is limited by the length of the arm (14) and the fixing of the sash attachment member (18) in the channel (20) of the sash (4). As the sash (4) is tilted further open, the downwards force (i.e. load) acting on the sash restrictor increases. The radial and/or axial frictional forces which act between at least one of: the components of the respective connection means; the respective attachment member and the respective connection means; and the respective connection means and the respective end of the arm, provide sufficient resistance to the tilting movement of the sash (4) to prevent the sash (4) from being dropped or falling suddenly whilst being tilted open. The radial and/or axial frictional forces also provide sufficient resistance to support the weight of the sash (4) in a partially tilted open position (Figure 1B) and so restrict it from opening further unless a sufficient external downwards force is applied to overcome the frictional forces. In a fully tilted open position (Figure 1A) the weight of the sash (4) is supported by the increased radial and/or axial frictional forces and/or the arm (14). To close the window sash (4) back to a vertical position, a sufficient external upwards force must be applied to overcome the radial and/or axial frictional forces.

Turning now to Figure 3, there is shown an alternative embodiment of the first connection means (124). The alternative embodiment (124) is the same as the first connection means (24) as shown in Figure 2, with the exception of the first rivet 130, the first sleeve 132 and the aperture 136, which have a countersunk shape. The slanted surfaces of the countersunk rivet 130, sleeve 132 and aperture 136 have a larger surface area compared to the T-shaped first rivet 30, first sleeve 32 and aperture 36, and thus the friction in the joint is increased. The alternative first connection means 124 can be used in place of one or both of the first connection means 24 in order to increase the force required to open the sash.

Turning to Figure 4, there is shown an alternative second connection means 128. The alternative second connection means 128 is the same as the second connection means 28, with the exception of the second rivet 44 being replaced with a threaded rivet assembly 200. The threaded rivet assembly 200 has a bolt 202 with a head 204 and a threaded shaft 206. The threaded shaft 206 is received within a nut 208 which has a head portion 209, threaded internal channel 210 and a frusto-conical exterior surface 212. An expanding sleeve 214 is held in position by the head of the bolt portion 202 and top edge of the nut 208, and surrounds the exterior surface 212 of the nut 208. The threaded rivet assembly is further housed within a sleeve 246.

In use, tightening the threaded rivet assembly 200, i.e. by rotating the bolt 202 within the nut 208, pulls the head portions 204, 209 of the bolt 202 and nut 208 closer together and increases the axial friction generated when the arm 14 is rotated. Additionally, pulling the bolt 202 and but 208 closer together causes the rivet sleeve 214 to be forced further onto the frusto-conical surface 212 of the nut, thereby applying a radial force onto the interior surfaces of the joint. Thus, the amount of friction which must be overcome in order to rotate the arm 14 can be manually adjusted. Additionally, the threaded rivet assembly 200 can be easily unscrewed and removed, thereby allowing for easy replacement should the joint become worn with use, or otherwise damaged.

The threaded rivet assembly 200 does not require a second washer 48, since it has an increased width. In some embodiments, the threaded rivet assembly 200 may be used with a second washer 48.

In further embodiments (not shown), it is envisaged that the alternative second connection means 124 may be used in the second connection means 28 at the second end 26 of the arm 14. Similarly, the threaded rivet assembly 200 may be used in the first connection means 24 at the first end 22 of the arm 14. Lastly, it is envisaged that the sash window assembly may comprise any combination of the attachment means as shown in Figures 2, 3 and 4.

Claims

CLAIMS:

1. A sash restrictor for restricting the movement of a window sash relative to a vertical plane of a window frame, said sash restrictor comprising: an arm, said arm having a first end and a second end; a frame attachment member configured for engagement with a track of a window jamb; a first connection means, said first connection means pivotally connecting the first end of the arm to the frame attachment member; a sash attachment member configured for engagement in a channel of a window sash; and a second connection means, said second connection means pivotally connecting the second end of the arm to the sash attachment member; wherein, the sash restrictor is configured to restrict the movement of the window sash relative to the vertical plane of the frame by pivotal frictional forces which resist relative movement between at least one of the respective attachment members and the arm as the load on the sash restrictor increases.

2. The sash restrictor according to claim 1, wherein the movement of the window sash is restricted by the pivotal frictional forces providing sufficient resistance to the control the rate of opening of the window sash.

3. The sash restrictor according to claim 1 or claim 2, wherein the movement of the window sash is restricted by the pivotal frictional forces providing sufficient resistance to support the weight of the sash in a tilted open position.

4. The sash restrictor according to any preceding claim, wherein the pivotal frictional forces comprise radial frictional forces which act between at least one of: respective circumferential surfaces of the first connection means; respective circumferential surfaces of the first connection means and the frame attachment member; respective circumferential surfaces of the first connection means and the first end of the arm; respective circumferential surfaces of the second connection means; respective circumferential surfaces of the second connection means and the sash attachment member; and respective circumferential surfaces of the second connection means and the second end of the arm.

5. The sash restrictor according to any preceding claim, wherein the pivotal frictional forces comprise axial frictional forces which act between at least one of: opposing faces of the first connection means and the frame attachment member; opposing faces of the first connection means and the first end of the arm; opposing faces of the second connection means and the sash attachment member; and opposing faces of the second connection means and the second end of the arm.

6. The sash restrictor according to any preceeding claim, wherein the frame attachment member is configured to be slidably engaged with the track.

7. The sash restrictor according to any preceding claim, wherein the sash attachment member is configured to be fixedly engaged in the channel of the window sash.

8. The sash restrictor according to any preceding claim, wherein the first connection means comprises a first fastener, a first sleeve and a first washer.

9. The sash restrictor according to claim 8, wherein the first sleeve has a friction fit around the first fastener.

10. The sash restrictor according to claim 8 or claim 9, wherein the first washer has a friction fit around the first sleeve.

11. The sash restrictor according to any one of claims 8 to 10, wherein the first washer is located between the frame attachment member and the first end of the arm.

12. The sash restrictor according to any one of claims 8 to 11, wherein a first face of the first washer is in contact with the frame attachment member and/or a second face of the first washer is in contact with the first end of the arm.

13. The sash restrictor according to any one of claims 8 to 12, wherein the first washer is compressible.

14. The sash restrictor according to any one of claims 8 to 13, wherein the radial frictional forces act between at least one of: a circumferential surface of the first fastener and an inner circumferential surface of the first sleeve; an edge of an aperture in the frame attachment member and an outer circumferential surface of the first sleeve; an inner circumferential surface of the first washer and an outer circumferential surface of the first sleeve; and an edge of a first hole in the first end of the arm and the outer circumferential surface of the first sleeve, as the load on the sash restrictor increases.

15. The sash restrictor according to any one of claims 8 to 14, wherein the axial frictional forces act between at least one of: the first face of the first washer and the frame attachment member; and the second face of the first washer and the first end of the arm as the load on the sash restrictor increases.

16. The sash restrictor according to any one of claims 8 to 15, wherein the first fastener is a rivet.

17. The sash restrictor according to any one of claims 8 to 16, wherein the first sleeve and/or the first washer is made of a plastics material.

18. The sash restrictor according to any preceding claim, wherein the second connection means comprises a second fastener, a second sleeve and a second washer.

19. The sash restrictor according to claim 18, wherein the second sleeve has a friction fit around the second fastener.

20. The sash restrictor according to claim 18 or claim 19, wherein the second washer has a friction fit around the second sleeve.

21. The sash restrictor according to any one of claims 18 to 20, wherein the second washer is located between the sash attachment member and the second end of the arm.

22. The sash restrictor according to any one of claims 18 to 21, wherein a first face of the second washer is in contact with the sash attachment member and/or a second face of the second washer is in contact with the second end of the arm.

23. The sash restrictor according to any one of claims 18 to 22, wherein the second washer is compressible.

24. The sash restrictor according to any one of claims 18 to 23, wherein the radial frictional forces act between at least one of: a surface of the second fastener and an inner surface of the second sleeve; an edge of an aperture in the sash attachment member and an outer circumferential surface of the second sleeve; an inner circumferential surface of the second washer and an outer circumferential surface of the second sleeve; and an edge of a second hole in the second end of the arm and the outer circumferential surface of the second sleeve, as the load on the sash restrictor increases.

25. The sash restrictor according to any one of claims 18 to 24, wherein the axial frictional forces act between at least one of: the first face of the second washer and the sash attachment member; and the second face of the second washer and the second end of the arm as the load on the sash restrictor increases.

26. The sash restrictor according to any one of claims 18 to 25, wherein the second fastener is a rivet.

27. The sash restrictor according to any one of claims 18 to 26, wherein the second sleeve and/or the second washer is made of a plastics material.

28. The sash restrictor according to any preceding claim, wherein the sash attachment member further comprises a friction block.

29. The sash restrictor according to claim 28, wherein the friction block is fixed to the sash attachment member.

30. The sash restrictor according to claim 28 or claim 29, when dependent on any one of claims 18 to 27, wherein the friction block is in contact with an outer circumferential surface of the second washer.

31. The sash restrictor according to claim 30, wherein radial frictional forces act between the friction block and the outer circumferential surface of the second washer as the load on the sash restrictor increases.

32. The sash restrictor according to any one of claims 28 to 31, wherein the friction block comprises a recess.

33. The sash restrictor according to claim 32, when dependent on any one of claims 18 to 27, wherein the recess is in contact with an outer circumferential surface of the second washer.

34. The sash restrictor according to claim 33, wherein radial frictional forces act between the recess and the outer circumferential surface of the second washer as the load on the sash restrictor increases.

35. A sash window assembly for restricting the movement of a window sash relative to a vertical plane of a frame, said sash window assembly comprising: a frame comprising a head, a sill and a pair of jambs, each jamb having a track defined therein; at least one window sash, the or each sash comprising a pair of channels and being vertically slidable in relation to the frame and tiltable with respect to a vertical plane of the frame; and at least one sash restrictor according to any one of claims 1 to 34; wherein the or each frame attachment member is engaged with the track of a respective jamb and the or each sash attachment member is engaged in the channel of a respective window sash.

36. The sash window assembly according to claim 35, comprising a pair of sash restrictors for the or each window sash.

37. A sash restrictor substantially as described herein with reference to Figures 1 to 4.

38. A sash window assembly substantially as described herein with reference to Figures 1 to 4.