GB2365062A

GB2365062A - Movement-limiting arrangements

Info

Publication number: GB2365062A
Application number: GB0018622A
Authority: GB
Inventors: Pierre Simon; Michel Reveillon; Olivier Mathieu
Original assignee: Draftex Industries Ltd; Trelleborg AB
Current assignee: Laird Holdings Ltd; Trelleborg AB
Priority date: 2000-07-28
Filing date: 2000-07-28
Publication date: 2002-02-13
Anticipated expiration: 2020-07-28
Also published as: HK1041719B; GB2365062B; GB0018622D0; HK1041719A1

Abstract

A movement-limiting arrangement, such as a vehicle door stay, has relatively moveable first and second members 10, 12 and a mechanical arrangement held magnetically in a locking position, to prevent relative movement between the members but releasable under a force of sufficient strength. The arrangement is held in the unlocked position while a smaller force is applied between the members. Member 10 maybe a rod carrying a nut 34 with a magnet 36 and teeth 38 cooperating with a magnetic toothed rail 30 on the member 12. An axial force on the rod above the first threshold cams the nut out of engagement with the rail and a subsequent lesser force shifts the nut axially to produce a holding engagement between a pin 26 or 28 and a slot 40. On release of the force a spring 22 or 24 establishes locking engagement again between the nut and the rail.

Description

<Desc/Clms Page number 1> MOVEMENT-LIMITING ARRANGEMENTS The invention relates to movement-limiting arrangements. One movement-limiting arrangement, to be described below in more detail by way of example only, is for temporarily arresting a hinged vehicle door in any one of a number of angular positions relative to the body of the vehicle. However, arrangements embodying the invention can be used in many other applications.

According to the invention, there is provided a movement-limiting arrangement, comprising first and second members relatively movable in response to an applied force, a mechanical locking arrangement held magnetically in a locking configuration to block relative movement between the two members when the applied force is less than a first datum value, means responsive to temporary application of a force higher than the first datum value between the two members to move the locking arrangement into an unlocked configuration to permit relative movement between them, and holding means responsive to an applied force at least equal to a second datum value which is less than the first datum value for temporarily holding the mechanical locking arrangement in the unlocked configuration to allow relative movement of the first and second members, reduction of the applied force to less than the second datum value releasing the holding means and causing the mechanical locking arrangement to move into the locking configuration. According to the invention, there is further provided a door stay for holding a hinged door

in any one of a plurality of angular positions relative to a frame thereof, comprising a longitudinally extending guide member adapted to be fixed relative to the frame, a longitudinally extending rod adapted to be attached to the door and mounted for movement substantially parallel to and alongside the guide member in response to the angular movement of the door, a toothed rack fixed to and extending at least partway along the guide member, a toothed locking control unit mounted on and to be carried by the rod alongside the guide member and angularly movable on the rod between a locked position in which its teeth are held magnetically in engagement with the teeth of the rack whereby to lock the rod relative to the guide member and correspondingly to lock the door in a particular angular position, the toothed engagement between the locking control unit and the rack being such that the application of an unlocking force to the rod exceeding a first datum value causes the locking control unit to move out of toothed engagement with the rack against the magnetic attraction to enable the rod to move relative to the guide member and thus to enable the door to be moved angularly, and holding means responsive to the continued application to the rod of a holding force exceeding a second datum value less than the first datum value to hold the locking control unit in a released position whereby to allow the rod to be moved relative to the guide member in response to and during the continuance of the holding force.

Movement-limiting arrangements embodying the invention, and in the form of door stays for vehicle doors, will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which:

Figure 1 is a side view of one of the arrangements; Figure 2 is a section on the line II-II of Figure 1 showing a magnetised nut unit used in the arrangement of Figure 1; Figure 3 corresponds to Figure 2 but shows the nut in an alternative configuration; Figure 4 shows teeth incorporated in the nut unit of Figures 2 and 3 to an enlarged scale; Figure 5 is a perspective view of part of the arrangement of Figure 1 showing the nut unit in an engaged position; and Figure 6 corresponds to Figure 5 but shows the nut unit in a released position.

Figure 1 is primarily intended to explain the operation of the arrangement and some of its parts are shown only diagrammatically as compared with Figures 2 to 6.

The movement-limiting arrangement to be described in more detail below may be used as a door stay for controlling the opening and closing movement of a hinged vehicle door, so as to enable the door to be held temporarily in any one of a number of angular positions relative to the vehicle body. However, it may be used in other applications. The arrangement incorporates a rod 10 which is connected to the door and which slides

longitudinally with respect to a generally cylindrical guide 12 which is fixed to the vehicle body. When the rod 10 has moved in the direction A to its outermost position with respect to the guide 12, the door is fully opened. When the rod 10 has moved to the maximum extent in the opposite direction B, the door is fully closed.

The rod 10 carries a magnetised nut unit 14 which acts as a locking control unit in a manner to be described in more detail below. The nut unit 14 is rigidly connected to two rings 16,18 and is slidable to and fro along the rod 10 with these rings. It is encompassed by a rigid frame 20 which is freely slidable on the rod 10 and is frictionally slidable on the guide 12. Compression springs 22,24 act between the frame 20 and the rings 16 and 18 respectively. Two pawls 26,28 are mounted on opposite sides of the frame 20 and are in the form of pins directed towards opposite sides of the nut unit 14. However, the pawls 26,28 are clear of the nut unit 14 when the nut unit is held in its midway position, within the frame 20, as shown in Figure 1.

The cylindrical guide 12 supports a rail 30 presenting a generally flat surface and which extends longitudinally within the guide and is made of ferromagnetic material. Adjacent to the rail 30, a toothed rack 32 is positioned.

Figures 2 and 3 show the shape of the nut unit 14 which comprises plastics material 34 carrying a permanent magnet 36 and teeth 38 and formed with a curved through slot 40. Figure 4 shows the nut unit 14 but viewed from the side opposite to the side visible in

Figure 1 and removed from the mechanism.

The operation of the arrangement will now be described.

The nut unit 14 is normally held in the position shown in Figure 2, with the permanent magnet 36 magnetically attracted to and in contact with the ferromagnetic rail 30. This position of the nut unit 14 is also shown in Figure S. The teeth 38 are thus magnetically held in engagement with the rack 32. This engagement of the teeth provides a locked configuration in which the rod 10 is locked to the guide 12. The door of the vehicle is thus held locked in a particular angular position relative to the vehicle body according to the position of the rod 10 in relation to the guide 12.

However, if a user of the vehicle applies a sufficient opening or closing force to the vehicle door, the rod 10 tends to move in the direction A or B (according to whether the force applied to the door tends to open or close it), and will tend to move the nut unit 14 in the same direction, relative to the guide 12 and the rack 32. As shown in Figure 4, the shape of the teeth 38 on the nut unit 14 is such that the applied force causes slight movement in an axial direction of the nut unit 14 thereby producing a couple which angularly turns the nut unit 14 around the rod 10 and away from the rack 32, against the attractive force of the permanent magnet 36. This is shown in Figures 3 and 6. It will initially be assumed that the rod 10 is moving in the direction of the arrow A (in response to opening of the door). As the rod 10 moves, it carries the nut unit 14 with it, so that

spring 22 transmits this movement to the frame 20. However, there is a relatively high coefficient of friction between the frame 20 and the guide 12. Spring 22 is therefore compressed and the nut unit 14 moves away from its centralised position within the frame 20. Pin 26 now engages the curved slot 40 in the nut unit 14. This engagement holds the nut unit 14 away from the rack 32 as the rod 10 continues to be drawn in the direction of the arrow A by the opening force applied to the vehicle door.

In this way, therefore, a relatively high force has to be applied to the vehicle door in order to overcome the magnetic attraction between the magnet 36 and the ferromagnetic rail 30, but, after such disengagement, the nut unit 14 is held away from the rack 32 by the engagement of the pawl 26 in the slot 40 and the applied force merely has to overcome the friction between the frame 20 and the guide 12.

When the vehicle door has been opened to the desired extent, the user stops applying the opening force. Spring 22 now resiles, and moves the nut unit 14 back onto its midway position between the opposite sides of the frame 20. Pawl 26 is now disengaged from the slot 40, and the magnetic attraction between the permanent magnet 36 and the rail 30 causes the teeth 38 to engage the rack 32 again, thus locking the door in the new angular position.

The process can then be repeated, to open the door to a further extent and then to lock it in the new position.

A resilient abutment 42 is provided which the frame 20 abuts to limit the fully open position of the door.

Figure 1 shows the upper part of the frame 20 as extending in front of the rail 30 and the rack 32. The frame is shown slightly differently in Figures 5 and 6.

When the door is moved to the closed position, the rod 10 moves in the direction of the arrow B. In the same manner as already described, the door is held in a particular angular position relative to the vehicle body by engagement of the teeth 38 of the nut unit 14 with the teeth on the rack 32. However, when the user applies a sufficiently high closing force to the door, a couple is set up by the force acting on the teeth 38, causing the nut unit 14 to turn angularly away from the rack 32 against the magnetic force as shown in Figures 3 and 6. Continued application of the closing force causes spring 24 to become compressed and to apply the force to the frame 20, sliding it in the direction of the arrow B, relative to the guide 12, and against the frictional force acting between the frame and the guide. Pawl 28 thus enters the slot 40 in the nut unit 14 and holds the nut unit 14 away from the back 32. The force now necessary to continue to move the door in the closing direction is dependent substantially only on the frictional force between the frame 20 and the guide 12. When the user has closed the door to the desired extent, the closing force is released, the spring 24 resiles, the nut unit 14 now becomes centralised within the frame 20 and the pawl 28 is thus released from the slot 40. The nut unit 14 now moves back into the position shown in Figures 2 and 5 where the magnet 36 contacts the rail 30

and holds the teeth 38 in engagement with the rack 32 so that the door is now locked. Advantageously, the rack 32 has an un-toothed portion 32A which corresponds to a relatively small range of angular movement of the door (e.g. a range of about 20 angular degrees) from its fully closed position. Therefore, the door cannot be locked into any angular position within this range of angular movement.

Claims

CLAIMS 1. A movement-limiting arrangement, comprising first and second members relatively movable in response to an applied force, a mechanical locking arrangement held magnetically in a locking configuration to block relative movement between the two members when the applied force is less than a first datum value, means responsive to temporary application of a force higher than the first datum value between the two members to move the locking arrangement into an unlocked configuration to permit relative movement between them, and holding means responsive to an applied force at least equal to a second datum value which is less than the first datum value for temporarily holding the mechanical locking arrangement in the unlocked configuration to allow relative movement of the first and second members, reduction of the applied force to less than the second datum value releasing the holding means and causing the mechanical locking arrangement to move into the locking configuration.
2. An arrangement according to claim 1, in which the two members are constrained for the relative movement alongside each other.
3. An arrangement according to claim 2, in which the mechanical locking arrangement comprises a toothed rack fixed to and running along the second member and a toothed locking control means carried by the first member, the locking control being movable towards the second member into a locked position in which it is in toothed

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engagement with the rack and held by magnetic attraction in that configuration and movable away from the second member into a released position.
4. An arrangement according to claim 3, including magnetic material and magnet means each carried by a respective one of the rack and the locking control means which act magnetically together to hold the mechanical locking arrangement in the locking configuration.
5. An arrangement according to claim 3 or 4, in which the teeth are so mutually shaped that the temporary application of the force higher than the first datum value forces the locking control means into the released position against the magnetic attraction.
6. An arrangement according to any one of claims 3 to 5, in which the holding means comprises means juxtaposed with the locking control means for engagement with the locking control means in response to the application of the applied force at least equal to the second datum value when the locking control means is in the released position for holding the locking control means in the released position.
7. An arrangement according to claim 6, in which the holding means comprises means frictionally mounted on the second member for movement therealong in response to the application thereto of the force at least equal to the second datum value, and including spring means acting between the locking control means and the holding means

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and biassing the holding means out of engagement with the locking control means until the application of the applied force at least equal to the second datum value when the locking control means is in the released position.
8. An arrangement according to any one of claims 3 to 7, in which the rack extends only partway along the second member.
9. An arrangement according to any preceding claim, in which the first member is a rod extending within the second member.
10. A door stay for holding a hinged door in any one of a plurality of angular positions relative to a frame thereof, comprising a longitudinally extending guide member adapted to be fixed relative to the frame, a longitudinally extending rod adapted to be attached to the door and mounted for movement substantially parallel to and alongside the guide member in response to the angular movement of the door, a toothed rack fixed to and extending at least partway along the guide member, a toothed locking control unit mounted on and to be carried by the rod alongside the guide member and angularly movable on the rod between a locked position in which its teeth are held magnetically in engagement with the teeth of the rack whereby to lock the rod relative to the guide member and correspondingly to lock the door in a particular angular position, the toothed engagement between the locking control unit and the rack being such that the application of an unlocking force to the rod exceeding a first datum value causes the locking control

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unit to move out of toothed engagement with the rack against the magnetic attraction to enable the rod to move relative to the guide member and thus to enable the door to be moved angularly, and holding means responsive to the continued application to the rod of a holding force exceeding a second datum value less than the first datum value to hold the locking control unit in a released position whereby to allow the rod to be moved relative to the guide member in response to and during the continuance of the holding force.
11. A door stay according to claim 10, in which the locking control unit carries magnet means and includes magnetic material extending at least partway along the guide member.
12. A door stay according to claim 10 or 11, in which the holding means comprises means frictionally slidable along the guide member in response to an applied force corresponding to the holding force and carrying a holding member which is normally held clear of the locking control unit by spring means acting between them but which engages the locking control unit to hold it in the unlocked configuration when the holding force is applied to the rod and the locking control element is in the released position.
13. A door stay according to any one of claims 10 to 12, in which the toothed rack is absent along part of the guide member alongside which the rod moves whereby the locking control unit cannot be moved into the locking position when adjacent this part of

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the guide member.
14. A movement-limiting arrangement, substantially as described with reference to the accompanying diagrammatic drawings.