GB2303172A

GB2303172A - Friction slider

Info

Publication number: GB2303172A
Application number: GB9514182A
Authority: GB
Inventors: Yurek Adrian Wronski
Original assignee: Cotswold Architectural Products Ltd
Current assignee: Cotswold Architectural Products Ltd
Priority date: 1995-07-12
Filing date: 1995-07-12
Publication date: 1997-02-12
Anticipated expiration: 2015-07-12
Also published as: GB9514182D0; GB2303172B

Abstract

A friction slider, e.g. for a window stay-hinge, which is movable along a track is formed with a recess (22) which receives a brake element (20) for engaging the track and the mutually engaging surfaces of the recess and brake element are formed with complementary cam surfaces so that rotation of the brake element alters the extent to which it protrudes from the recess and thus its braking force. Both surfaces are also formed with teeth to define a series of adjustment positions.

Description

SLIDER This invention relates to friction sliders, for example such as are used in hinges in the form of stays such as window stays. They may also be used in shoot bolts sashwindow springs and other devices in which a controlled sliding movement is required.

Stays of the type comprising an arm for supporting a window, a track member, a slider moveable along the track member, a strut pivotally connected to the track member and spaced from the slider, a brace pivotally connected to the slider and a strut, and a link pivotally connected to the slider, the arm being pivotally connected to the link and the strut for movement between the first position which overlies the track member and a second outward position in which it extends at an angle to the track member are well known and will hereinafter be referred to as a stay of the type described. Purely by way of example such a stay is described in our Patent Application No. 2255588.

The ease with which a window can be opened, and the extent to which a window will stay in the position in which it has been placed, depends, at least in part, on the frictional engagement between the undersurface of the main body of the slider and the bottom of the track member.

Usually the appropriate level of engagement cannot be determined until the stay is in situ mounting a window within a frame. It is therefore usual to provide some form of adjustment so that the engagement of the slider in the track member can be adjusted by the fitter. In most practical stays, which are on the market, this adjustment is provided by a brass grub screw which extends through the slider so that its slotted end is exposed for adjustment and its other end can project to an adjustable degree from the bottom of the slider. In general this system works well, although some scratching of the track can occur. However, the screws are expensive and the necessity of tapping a hole formed in the slider introduces extra cost.Proposals have been made wherein the grub screw deflects a flexible undersurface of the slider providing a better spread of frictional engagement and removing the risk of scratching, but this type of arrangement is even more expensive. Other proposals have included non-circular rotatable elements disposed within the slider body and formed with cam portions which can displace the side walls of the slider outwardly against side walls of the track member. This means that the side walls must be flexible and hence weak. Similar considerations exist in other areas wherein a slider moves within a track for example in shoot bolt construction and the brake assembly of a sashwindow spring.

According to one aspect the invention consists in a slider for movement in a track member, including a main body for slidable mounting in the track member and having a recess in its undersurface, with engages the track member in use, and a brake element disposed in the recess and extending through the slider to expose an operably engageable portion, whereby the element can be rotated relative to the slider, wherein the upper end of the recess and the opposed face of the element define cooperable formations formed such that rotation of the element causes movement of the element into and out of the recess for varying the degree of engagement between the element and the track, in dependence on the direction of rotation.

Conveniently the full rectilinear movement of the element is achieved with a rotation of less than 360" and preferably that movement is achieved with a rotation of approximately 1800.

The recess may have an opening in its upper end through which the operably engageable portion extends and the brake element may have a body for engaging the track. In a particularly convenient arrangement the body is in the form of a circular disc and the operably engageable portion comprises a central stalk which, may be integral with the body. ie. the brake element may be in the form of an inverted mushroom.

The formations may be part spiral cam paths and each of the recess and element may have a pair of part spiral cam paths. Conveniently each cam path extends over approximately 180 and the transitions between the cam paths may act as a stop.

Each cam path may be formed with lateral teeth for defining a succession of rotational positions for the element.

It is particularly preferred that the main body and the brake element are each respective integral mouldings. In this case there are no additional manufacturing steps, eg.

tapping, which have to be carried out; the brake element is simply push-fitted into the slider in its most withdrawn position.

In another aspect the invention includes a stay of the type described including a slider as hereinbefore defined.

Although the invention has been defined above it is to be understood that it includes any inventive combination of the features set out above or in the follow description.

The invention may be performed in various ways and the specific embodiment will now be described, by way of example, with reference to the accompanying drawings, which; Figure 1 is a view of prior art stay, illustrating a stay of the type described; Figure 2 is a view from above of a slider in accordance with the present invention; Figure 3 is an exploded side view of Figure 2 with the main body of the slider partly in section along the line III-III; Figure 4 is a view from below of the slider, with the brake element removed; Figure 5 is an enlarged view on the Detail A of Figure 3; Figure 6 is a section along the line VI-VI in Figure 5; Figure 7 is an enlarged view from above of the brake element of Detail B in Figure 3; Figure 8 is a view of the element of Figure 7 on the arrow; and Figure 9 is a view of the brake element of Figure 7 along the arrow Y.

For convenience an embodiment of the invention will be described in connection with a stay of the type described.

However, as has already been mentioned, the slider can be used in other analogous situations.

Figure 1 illustrates a prior art stay, which is generally indicated at 10. The stay comprises an arm 11 for supporting a window, a track member 12, a slider 13 movable along the track member 12, a strut 14 connected to the track member and spaced from the slider, a brace 15 pivotally connected to the slider 13 and the strut 14 and a link 16 toothily connected to the slider 13, the arm 11 being pivotally connected to the link 16 and strut 14 for movement between the first position which overlies the track member 12 and the second outward position (as illustrated in the Figure) in which it extends at an angle of the track member 12. The slider 13 has a grub screw 17, which extends through a tapped hole in the slider 13, to engage the surface 12a of the track member 12 to a degree determined by its position within the tapped hole. Its function has previously been described. The other features of the stay are not relevant for present purposes. It will be understood that as the arm moves between its first and second positions the slider 13 moves along the track with an ease determined by the degree to which the grub screw 16 protrudes from its under surface.

Turning to Figure 2 to 9, an alternative slider is generally indicated at 18. It comprises a main elongate rectangular body 19 and a brake element 20. The slider has two openings 21, 22 for receipt of the link and brace pivots respectively. It is further formed with a recess 22, which opens on to its under surface 23 and which has an associated central through hole 24.

The brake element 20 is in the form of an inverted mushroom,the head 25 of which acts as the brake and the stalk 26 of which extends through the through hole 24 to present a screw diver slot 27 to the fitter so that he can rotate the brake element 20 by using a screwdriver.

As can best be seen in Figures 5 to 9, the recess 22 and head 25 are formed with respective pairs 28, 29 and 30, 31 of 1800 spiral cam paths. Cam paths 30, 31 are formed on the upper side of the head 25 so that they directly face cam paths 28, 29 which are formed in the upper surface of the recess 22.

When the brake element 25 is push-fitted into the recess 22, its axial position is determined by the engagement of the cam paths. This can then be adjusted by rotating the brake element 25, by means of the slot 27 and stalk 26, so that the cam paths 30, 31 on the brake element 20 slide on their respective associated paths 28, 29. As this movement takes place the brake element either cams into or out of the recess 22 depending on the direction of rotation. The degree of projection of the head 25 determines the frictional engagement of the slide 18 with the track 12.

All of the cam paths are provided with symmetrical teeth 32 so that they can engage between teeth on their opposed cam paths to define a series of rotational positions.

As has been mentioned before, both the brake element 20 and the slide 18 can be moulded from plastics and this design accordingly introduces considerable cost saving both in components and the manufacturing and assembling. It also allows the brake element 20 to have a large engagement area.

Claims

1. A slider for a stay of the type described including a main body having a recess in its undersurface which engages the track member in use, a brake element disposed in the recess and extending through the slider to expose an operably engageable portion whereby the element can be rotated relative to the slider wherein upper the upper end of the recess and the opposed face of the element define cooperable formations formed such that rotation of the element causes movement of the element into and out of the recess for varying its degree of engagement with the track in dependence on the direction of rotation.

2. A slider as claimed in claim 1 wherein the full rectilinear movement of the element is achieved with a rotation of less than 3600.

3. A slider as claimed in claim 2 wherein the full rectilinear movement of the element is achieved with a rotation of approximately 1800.

4. A slider as claimed in any one of the preceding claims wherein the brake element has a body for engaging the track and a central stalk which extends through the slider and defines the operably engageable portion.

5. A slider as claimed in any one of the preceding claims wherein the formations are part spiral cam paths.

6. A slider as claimed in claim 5 wherein each of the recess and element has a pair of part spiral cam paths.

7. A slider as claimed in claim 5 or claim 6 wherein each cam path is formed with lateral teeth for defining a succession of rotational positions for the element.

8. A slider as claimed in any one of the preceding claims wherein the main body and brake are each respective integral mouldings.

9. A slider as claimed in any one of the preceding claims wherein the brake element is a push-fit in the slider.