GB2068451A - Travel limiting devices - Google Patents

Abstract

A device for limiting the travel e.g. of a door 4 in like manner to a conventional door chain has a bracket 1 to which is pivoted an arm 6. The arm has longitudinal grooves 7A, 7B with cut-outs 8A, 8B through which pegs 19A, 19B fixed to the door can enter the grooves, the opening travel of the door being limited by movement of the pegs to the closed ends 6A of the grooves.The arm 6 is furthermore movable longitudinally relative to the bracket 1 against the bias of a spring 10 and must be pulled radially outwards from the bracket against this bias to pass the pegs 19A, 19B through the cut-outs 8A, 8B. This action ensures that the arm is latched positively in its "on guard" condition. <IMAGE>

Description

SPECIFICATION Travel limiting devices The present invention relates to travel limiting devices for doors, windows or other movable members and is concerned especially with a device designed to serve the same purpose as the well-known door chain - that is to say to enable the occupant of a house or other building or room to open a door through a limited distance sufficient to enable the occupant to observe and converse with a caller but insufficient to enable the caller to pass through the doorway, and the device requiring that the door then the first be closed, or virtually so, before the device can be disengaged to permit the door to open to the extent required for the caller to gain admission.

A device of this type is known which includes a bracket secured to the door frame and an arm pivoted to the frame bracket about a fixed axis parallel to the adjacent edge of the door. The arm has a parallel pair of longitudinal grooves which are closed at the distal end of the arm and have cut-outs in their sides at a location towards the proximal end of the arm. In addition there is a bracket secured to the door which has pegs for cooperation with respective groves in the arm.

The device is set up so that with the door closed the pegs lie on the paths described by the cut-outs in the grooves when the arm is pivoted relative to its mounting bracket. Consequently, by swinging the arm towards the closed door the pegs can enter the grooves through their cut-outs, and when the door is subsequently opened the pegs run along the grooves to the closed ends thereof, thereby limiting the distance through which the door can be opened. Such a device can be made to withstand a greater load than commonlyavailable door chains, is less susceptible to an attack with bolt cutters or the like, and is aesthetically more acceptable. An additional drawback of the door chain from which the swinging arm type of device does not suffer is that the chain can be overcome by inserting a rod through one of its links when the door is opened, and then twisting.

Nevertheless, the known swinging arm type of device indicated above does have drawbacks of its own. Particularly, when the arm is swung towards the closed door to enable the pegs of the door bracket to enter the grooves in the arm - i.e.

when the device is "on guard" so to speak there is nothing positively to retain it in that position, so it is possible for the occupant inadvertently to disengage the device when he opens the door, thereby rendering it ineffective to limit the door travel. More seriously perhaps, by the same token it is possible, in the case of a hinged door, for a potential intruder to overcome the device by waiting for the door to be unlocked and then giving the door a sharp push followed by an equally sharp pull (e.g. using a letter-box or knocker for this purpose) to project the arm away from the door and permit the door-mounted pegs to withdraw from their grooves in the arm.

Accordingly it is an aim of the invention to provide a travel limiting device usable for the purposes indicated above and which can share the advantages of the known swinging arm type of device while overcoming its above-mentioned drawbacks.

According to the invention, a device for limiting the opening travel of a door relative to its frame or between two other such relatively movable members comprises: mounting means for securement to one of the relatively movable members at a position adjacent to the edge of the other said member; an arm pivoted to the mounting means about an axis which in use is generally parallel to the adjacent edge of the other said member, the arm having a longitudinal groove closed at the distal end of the arm and the groove having an aperture in its side at a location towards the proximal end of the arm; and means for securement to the-other said member comprising an engaging element for cooperation with said aperture and groove; wherein in addition to pivotal movement relative to the mounting means the arm is capable of movement in its longitudinal direction relative to the mounting means between first and second positions respectively towards and away from the mounting means, the arm being biased resiliently towards said first position.

A device in accordance with the invention can be set up so that, with the two relatively movable members closed together, when the arm is in its second longitudinal position the aforesaid engaging member lies on the path of said aperture of the arm when the arm is pivoted relative to the mounting means so that the engaging element can enter or leave the groove in the arm through said aperture, but when the arm is in its first longitudinal position the pivotal path of the aperture is.displaced towards the mounting means so as to avoid the engaging element which thus cannot enter or leave the groove.Consequently, in use of such a device it can be placed "on guard" with the two relatively movable members closed together, by pulling the arm against its resilient bias from its first to its second longitudinal position relative to the mounting means while swinging the arm towards the engaging element whereupon the engaging element enters the groove in the arm through its aperture. If the arm is then released it moves back to its first longitudinal position under the influence of its resilient bias so that, in effect, the engaging element moves along the groove clear of the path of the aperture and remains trapped in the groove, the device thus positively being latched "on guard".To disengage the device the two members must be closed together, or virtually so, and the arm once more pulled against its resilient bias to enable the aperture to line up with the engaging element and permit the arm to be swung away.

Clearly, in the case of a hinged door, this action could not be performed from outside by a potential intruder employing the aforesaid "pushpull" technique. In a preferred embodiment the outboard portion of the arm is generally of H section, so as to define a parallel pair of said longitudinal grooves, one above the other, the engaging element being correspondingly duplicated.

The method by which the connection between the mounting means and the arm is effected to provide the desired pivotal and longitudinal motion of the arm is open to considerable variation. In a preferred embodiment, the mounting means bears a fixed-axis pivot pin and the arm is provided with a longitudinal slot through which it is borne on the pin with freedom for longitudinal movement, there being one or more torsion springs borne upon the pin so as to be pivotal with the arm but the or each spring having a portion bearing against the arm whereby the arm is biased as aforesaid. In another preferred embodiment the torsion spring(s) are replaced by a compression spring pivoted with the arm and acting effectively between the arm and the pin or some otherfixed part of the mounting means.

Again, instead of having a pivot axis for the arm fixed relative to the mounting means with the arm being movable longitudinally relative to the pivot axis, as in the above examples, the pivot axis may be fixed relative to the arm with the-arm and axis being movable longitudinally together relative to the mounting means.

The invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a plan view, with some parts broken away, of a first embodiment of a device according to the invention installed to limit the travel of a door; Figure 2 is a section on the line lI-Il of Figure 1; Figure 3A is a side view of the spring employed in the device of Figures 1 and 2; Figure 3B is a view of the spring taken in the direction of the arrow B in Figure 3A; Figure 3C is a view of the spring taken in-the direction of the arrow C in Figure 3B; Figure 4 is a plan view of the device of Figures 1 and 2 in its travel-limiting condition; Figure 5 is a view similar to Figure 1 of a second embodiment of a device according to the invention; and Figure 6 is a section on the line VI--VI of Figure 5.

Referring to Figures 1 and 2, a bracket 1 is shown secured by screws 2 to the frame 3 of a hinged door 4. The bracket has a pair of cheeks 1 A and 1 B defining a clevis within which is mounted a pivot pin 5. In the illustrated embodiment the pin 5 is shown mounted vertically - i.e. parallel to the adjacent edge 4A of the door 4. Borne upon the pin 5 between the cheeks 1 A and 1 B is a swinging arm 6. The main portion of the arm which lies outboard of the bracket is of H section, to define upper and lower longitudinal grooves 7A and 7B. These grooves are closed at the distal end 6A of the arm, and at their proximal ends there are respective cut-outs 8A, 8B in the side wall 6B of the arm which faces the door (when the device is in the illustrated condition).

The arm 6 is mounted to the pin 5 through a longitudinal slot 9, so that in addition to its pivotal motion the arm can move in its longitudinal direction over a limited range relative to the pin and bracket. Normally, however, the arm is biased by a spring 10 to adopt the longitudinal position relative to the pin which it is depicted in Figures 1 and 2 - i.e. with the arm drawn radially inwards against the pin to the limit permitted by the slot 9. The shape of the spring 10 is shown in Figure 3. In effect it comprises a pair of spacedapart, coaxial coils 1 A, 1 B each having a free tangential extension 1 2A, 1 2B and joined together by a U-shaped intermediate portion 13 the base of which is spaced laterally from the common axis of s the coils.In the assembled device shown in Figures 1 and 2 the coils surround the pin 5 and are accommodated in shallow recesses 14A, 14B in the arm 6 above and below the slot 9, the intermediate portion 13 of the spring extending between the two recesses and lying closely against the side of the arm. The recesses are shaped as shown in the figures to define faces 1 so, 1 SB against which respective extensions 1 2A, 1 2B of the spring bear.The arrangement is such that the spring 10 pivots about the pin 5 together with the arm 6, so that the arm when not in use can be swung back to lie against the wall adjacent to the door frame 3, but at all times the engagement of the extensions 1 2A, 1 2B against the faces 1 so, 1 SB provides a biasing action which urges the arm to adopt the aforesaid "inward" longitudinal position relative to the pin and bracket.

Secured to the door 4 by screws 16 is a second bracket 17. The latter has a pair of arms 1 8A, 1 8B terminating in vertically aligned pegs 1 9A, 1 9B so sized and spaced that each peg can be accommodated in a respective groove 7A, 7B of the arm 6.

in use of the device, when it is desired to put it "on guard" so as to limit the travel of the foor 4 when the latter is subsequently apened, the device must be placed in the condition shown in Figures 1 and 2. Assuming that the arm is initially swung back against the wall in its inoperative position, it is necessary to pull the arm radially outwards from the pin 5 to shift the arm longitudinally against the bias of the spring 10 - so that the pin 5 now lies at the end of the slot 9 opposite to that at which it is shown in Figures 1 and 2 - and at the same time swing the arm about the pin towards the door. The loci of the centres of the cut-outs 8A, 8B during this swinging movement are indicated at L1 on Figure 1 and it is seen that the pegs 1 9A, 1 9B lie on such loci. Thus, as the arm is swung towards the door in this condition the pegs can pass through the respective cut-outs and enter the respective grooves 7A, 7B. When the arm is then released, however, the action of the spring 10 is to draw the arm radially inwards against the pin 5, shifting the arm into the position shown in Figures 1 and 2 in which, in effect, the pegs 1 9A, 1 9B have moved a short way along their grooves 7A, 7B and are no longer lined up with the cut-outs, 8A, 8B (the loci of which in this condition are indicated for purposes of comparison at L2 in Figure 1). Consequently, the pegs 1 9A, 1 9B are now trapped in their grooves and cannot be removed from the grooves purely by swinging motion of the arm 6; in other words the device is latched in its "on guard" condition.

If the door 4 is now opened it will be appreciated that the pegs 1 9A, 1 9B will run along the grooves 7A, 7B while pivoting the arm 6, until the pegs reach the closed ends of the grooves at which point the device will prevent any further travel of the door in the opening direction; this condition is shown in Figure 4. It will also be appreciated that by virtue of the trapping of the pegs in the grooves a potential intruder will be unable to disengage the device by any sequence of pushing and pulling operations on the door 4.

To disengage the device the door must first be closed and the arm again pulled radially outwardly from the pin against the bias of the spring 10 to enable the cut-outs 8A, 8B to line up with the pegs 1 9A, 1 9B and permit the arm to be swung away from the door.

Turning now to Figures 5 and 6, these illustrate a second embodiment of a device in accordance with the invention of generally similar structure and equivalent function to that described with reference to Figures 1 to 4, like reference numerals being used to denote like parts in the two embodiments. In the embodiment of Figures 5 and 6 the arm 6 has a longitudinal slot 20 and a longitudinal bore 21 at its proximal end, and is mounted to a pivot pin 5 through a plastics insert 22 which is disposed in the slot 20 and trapped between the cheeks 1 A, and 1 B of the frame bracket 1. The insert 22 has a projection 23 over which a compression coil spring 24 is located, the spring extending into the bore 21 where it abuts a fixed cross-pin 25.The effect of this form of mounting is that the arm 6 is freely pivotable together with the insert 22 on the pin 5, and is also movable longitudinally relative to the insert and pin between the illustrated position and a position in which the insert 22 lies at the end of the slot 20 opposite to that at which it is shown in Figures 5 and 6. The arm is biased towards its illustrated longitudinal position, however, by the action of the spring 24 compressed between the insert 22 and pin 25. As has been indicated, this confers to the arm 6 a function in relation to the door bracket 1 7 which is equivalent to that in the embodiment of Figures 1 to 4, description of which accordingly will not be repeated.

Although the illustrated devices have been described above in terms of their application to a right-hand hinged door they are equally applicable to one with a left-hand hinge, the components simply being inverted for such an application.

Also, although described in terms of application to a door they are not restricted in this respect and can be used in similar fashion to limit the travel of windows or other movable members. Neither need the movable member necessarily be hinged. For example a device could be mounted in exactly the same manner as is illustrated to limit the movement of a door or other member 4 which opens by sliding (to the right as viewed in the figures) instead of pivoting. Again, instead of the pivoted arm being mounted on a fixed member and the cooperating pegs being mounted on the movable member, similar devices could be used with the mountings reversed, i.e. with the pegs on the fixed member and the arm on the movable member.

Further, such devices need not be restricted to use between a movable and a fixed member such as a door and its frame but can be applied to limit the relative travel of two movable members such as double doors or so-called French windows, where the bracket 1 and arm 6 would be mounted on one member and the bracket 1 7 mounted on an adjacent portion of the other member.

Claims (8)

1. A device for limiting the opening travel of a door relative to its frame or between two other such relatively mcvable members, comprising: mounting means for securement to one of the relatively movable members at a position adjacent to the edge of the other said member; an arm pivoted to the mounting means about an axis which in use is generally parallel to the adjacent edge of the other said member, the arm having a longitudinal groove closed at the distal end of the arm and the groove having an aperture in its side at a location towards the proximal end of the arm; and means for securement to the other said member comprising an engaging element for cooperation with said aperture and groove; wherein in addition to pivotal movement relative to the mounting means the arm is capable of movement in its longitudinal direction relative to the mounting means between first and second positions respectively towards and away from the mounting means, the arm being biased resiliently towards said first position.

2. A device according to Claim 1 wherein the outboard portion of the arm is generally of H section so as to define a parallel pair of said longitudinal grooves, one above the other and the means for securement to the other said member comprises a corresponding pair of said engaging elements, one for cooperation with each said groove.

3. A device according to Claim 1 or Claim 2 wherein the pivot axis for the arm is fixed relative to the mounting means, and the arm is movable longitudinally relative to the pivot axis.

4. A device according to Claim 3 wherein the mounting means bears a fixed-axis pivot pin and the arm is provided with a longitudinal slot through which it is borne on the pin with freedom for longitudinal movement, there being one or more torsion springs borne upon the pin so as to be pivotal with the arm but the or each spring having a portion bearing against the arm whereby the arm is biased as aforesaid.

5. A device according to Claim 3 wherein the mounting means bears a fixed-axis pivot pin and the arm is provided with a longitudinal slot through which it is borne on the pin with freedom for longitudinal movement, there being a compression spring pivotal with the arm and acting effectively between the arm and a fixed part of the mounting means whereby the arm is biased as aforesaid.

6. A device according to Claim 5 comprising an insert mounted on the pivot pin and located in said slot of the arm whereby the insert is pivotal with the arm and the arm is movable longitudinally relative to the insert, and said compression spring abuts at one end with said insert and at the other end with a portion of the arm.

7. A device according to Claim 1 or Claim 2 wherein the pivot axis for the arm is fixed relative to the arm, and the arm and pivot axis are movable longitudinally together relative to the mounting means.

8. A travel limiting device substantially as hereinbefore described with reference to Figures 1 to 4 or Figures 5 and 6 of the accompanying drawings.