Brakes – Vehicle – Ground-engaging
Reexamination Certificate
1998-10-05
2001-01-16
Butler, Douglas C. (Department: 3613)
Brakes
Vehicle
Ground-engaging
C188S111000, C188S001120, C188S069000
Reexamination Certificate
active
06173817
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a braking device for use with a vehicle which moves along a surface, the braking device being operated by means external to the vehicle, and particularly but not exclusively to a braking device for use with a wheeled trolley or cart to deter its removal from a designated area.
A particular problem with supermarket-type shopping trolleys or carts is the removal of these trolleys or carts from designated areas, such as the supermarket and/or its car park. Although various systems have been proposed for placing physical obstructions such as grids and/or narrow stalls at the exit points from these designated areas, which obstacles are intended to interact with the trolley's castor wheels or with the trolley itself to deter its removal, these known systems are easily overcome and are also unsuitable for certain applications, such as vehicle entrances for supermarket car parks.
A braking device designed to overcome these problems is described in International Patent Application No. WO92/15476. The device is designed to be activated as it passes over a member or area of magnetic material to cause a braking member to be applied to the ground to impede the trolley's continued movement. The braking device is conveniently associated with a castor wheel of the trolley. However, the environment of dust and heavy knocks which a trolley castor wheel has to withstand produces a weakness and unreliability in the locking and unlocking of this device. The present invention relates to an improvement of the type of device described in the above referred-to application.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, there is provided a braking device for mounting on a vehicle movable alone a surface comprising a first portion for mounting on the vehicle, a braking portion movable relative to the first portion from an inoperative position to an operative braking position in braking contact with the surface, and retaining means for retaining the braking portion in its inoperative position the retaining means being operable by external means, for example comprising magnetic material, to release the braking portion, the braking portion and retaining means being adapted to cooperate to prevent operation of the retaining means to release the braking portion in the absence of the external means.
A portion of the retaining means may abut a surface of the braking portion in such a way that relative movement of the retaining means and braking portion are prevented, the cooperation between the braking portion and retaining means being removed by application of a force to one of the components.
The retaining means may include blocking means and trigger means, the trigger means being moveable between a primed position and a triggered position by passage in close proximity to the external means. In the primed position, the trigger means may hold the blocking means in a blocking position preventing movement of the braking portion and, in moving to the triggered position, the trigger means may release the blocking means to allow the blocking means to move to its unblocking position to allow movement of the braking portion to its braking position on passage of the device past the external means, the braking portion cooperating with the blocking means to prevent movement of the blocking means from its blocking position to its unblocking position in the absence of the external means.
The blocking means may include a portion having a surface on an end portion which, in the blocking position of the blocking means, abuts a surface of the braking portion such that the blocking means prevents movement of the braking portion to its braking position and the braking portion prevents movement of the blocking means to its unblocking position. The braking portion may be adapted to be moved by the presence of the external means in a direction opposite the direction of its movement to its braking position, so as to release cooperation between the blocking means and the braking portion to permit movement of the blocking means to its unblocking position.
The device may include a stabilizing element which, in the primed position of the trigger means bears against the blocking means in the region of its contact with the trigger means so that, when the trigger means moves to its triggered position, the stabilizing element engages the trigger means to hold it in its triggered position.
For releasing cooperation between the blocking means and the braking position, as an alternative to movement of the braking portion, the stabilizing element may be arranged to apply a force to the blocking means when the trigger means moves to its triggered position.
In relation to the foregoing and what follows, the term “magnetic material” is used to denote a material which is affected by a magnetic force and can either be a magnet or a permanently magnetised material or a material, e.g. mild steel, which is attracted to a magnet or permanently magnetised material. It will be understood that where there are two separate elements of “magnetic material” which are to interact, one element may be permanently magnetised or a magnet and the other element may be made of a material which is attracted to it or may be a magnet or permanently magnetised to either be attracted to it or repelled by it. In the following description the term “attracted” is used but it will be understood that in a correspondingly modified arrangement, the two elements may be repelled.
According to another aspect of the present invention, there is provided a braking device for braking a vehicle movable along a surface including a first portion mounted on the vehicle and a further or braking portion movable relative to the first portion between an inoperative position and an operative braking position for contacting the surface to brake the vehicle, blocking means mounted on the first portion for blocking movement of the braking portion to its operative position and trigger means movable between a primed position and a triggered position in which the blocking means is released to allow movement of the braking portion to its braking position, the trigger means being moved from its primed position to its triggered position by passage of the device in close proximity to magnetic material, wherein to prevent inadvertent operation of the device, the braking portion co-operates with the blocking means to prevent movement of the blocking means to its unblocking position in the absence of the said magnetic material.
Cooperation between the braking portion and the blocking means may be released either by applying a force to the braking portion or to the blocking means.
The trigger means preferably includes a member mounted on the first portion which is arranged to move from its primed position to its triggered position as it passes in close proximity to magnetic material, e.g. a magnetic material strip mounted in the surface over which the vehicle moves. The member is advantageously pivotally mounted on the first portion and biassed to its primed position so that it will return to that position after operation. The trigger member may be pivotally mounted about its centre of gravity and biassed to its primed position by a spring. The member may be made of magnetic material or incorporate an element of magnetic material and may be generally elongate with one end closer to the surface over which the vehicle moves than the other.
The blocking means may also be pivotally mounted on the first portion.
The braking portion may include a member pivotally mounted on the first portion and arranged to be biassed by gravity towards its braking position. The member may have an eccentric circumferential surface portion which engages the surface over which the vehicle moves when the braking member is moved to its braking position. The member is arranged to pivot in a plane parallel to the direction of movement of the vehicle and in a direction such that continued movement of the vehicle will continue angular move
Butler Douglas C.
Dykema Gossett PLLC
Talavera Melanie
LandOfFree
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