ELEVATOR ARRANGEMENT
The present invention relates to a safety device in an elevator door opening as defined in the preamble of claim 1.
A safety device used in an elevator door opening is a foot guard, also called a toe guard, placed at the lower edge of the elevator car and having a length substantially at least equal to the width of the landing door opening. The toe guard is a plate-like piece or equivalent mounted in a substantially vertical plane, and it is designed to block the gap opening into the elevator shaft between the lower edge of the elevator and the floor surface of the landing e.g. when the elevator has stopped due to a failure so that the lower edge of the elevator car remains above the surface of the landing floor. This gap may be so large that a person escaping from the elevator can fall through the gap into the elevator shaft when descending from the car remaining above the surface of the landing floor. Likewise, without a toe guard there is a risk that a person who is working on a landing and loading or unloading e.g. a freight elevator remaining somewhat above the landing floor may inadvertently get so near the elevator shaft that his toes are in the shaft space. If the elevator car starts moving downwards in such a situation, there is a risk of the person's toes being injured. A toe guard functioning as a safety device ■ prevents the occurrence of this type of hazards .
Regulations concerning safety of elevators specify the minimum height of the above-mentioned toe guard as 750 mm. A problem with the use of a toe guard of such a large height is that there is not enough room for the toe guard in a low elevator shaft pit when the elevator car comes e.g. to the lowest level. In prior-art elevator solutions, various attempts have been made to address this problem.
To solve this problem, European patent application no. EP1118576 discloses a toe guard that can be folded or slid under the elevator car so that the elevator car can get closer to the bottom of the shaft. The solution according to this EP solution uses complex lever arms and guides for changing the position of the toe guard. The complex structure is more expensive and is additionally susceptible to damage.
Similarly, US patent no. US6, 095,288 discloses a toe guard that turns on hinges under the elevator car. In this solution, the bottom of the shaft is provided with a surface inclined at an angle of about 45° which receives rollers provided at the lower edge of the toe guard when the elevator car comes to its lowest position, with the result that that the toe guard, guided by the rollers, turns on its hinges to a position under the elevator car. One problem here is that the structure can become dirty, which may prevent the toe guard from being properly returned to the straight position or block the hinges so that the turning motion of the toe guard may become stiff, leading to a risk of breakdown of the whole structure.
International patent specification no. WO 02/10053 also discloses toe guard solutions to address the aforesaid problem. The embodiment presented in Figures 4 and 5 is a complex turn- able structure, which has the above-mentioned drawbacks. Figures 1 - 3 show a structural solution resembling the invention now disclosed, comprising a telescoping toe guard with an external lower part moving vertically on a fixed internal upper part. A problem with the solution described in this specification is dirt, which can easily get into the open spaces between the moving parts, causing operational disturbances.
The object of the present invention is to overcome the above- mentioned drawbacks and to achieve a reliably functioning safety device of economical cost for the door opening of an elevator, such as a toe guard. The safety device of the inven-
tion is characterized by what is disclosed in the characterization part of claim 1. Other embodiments of the invention are characterized by what is disclosed in the other claims.
Inventive embodiments are also presented in the description part of the present application. The inventive content disclosed in the application can also be defined in other ways than is done in the claims below. The inventive content may also consist of several separate inventions, especially if the invention is considered in the light of explicit or implicit sub-tasks or in respect of advantages or sets of advantages achieved. In this case, some of the attributes contained in the claims below may be superfluous from the point of view of separate inventive concepts. Within the framework of the basic concept of the invention, features of different embodiments of the invention can be applied in conjunction with other embodiments .
The advantages of the elevator safety device of the invention include a good tolerance of dirt, allowing reliable operation of the safety device. In addition, the safety device has a simple structure and allows the use of a toe guard of sufficient height in elevator shafts having a low pit. Moreover, the toe guard is automatically returned to its low position by gravity, thus obviating the need for complicated returning structures or resetting systems . Another advantage is that the toe guard of the invention can be installed on an existing elevator car without dismantling the old threshold structure. For mounting the toe guard, no additional components are needed, but the new toe guard fits directly in the place of the old one . A further advantage is the fact that no complex hinged solutions are needed. Yet another advantage is that the box-like structure gives a better stiffness in the direction of an impact applied to the toe guard than prior-art solutions, such an impact being most commonly caused by a person's knee.
In the following, the invention will be described in detail with reference to an embodiment example and the attached drawings, wherein
Fig. 1 is a diagram showing an elevator car in an elevator shaft, provided with a safety device according to the invention, above the lowest landing floor,
Fig. 2 presents the safety device of the invention as seen from behind
Fig. 3 presents the safety device of the invention in side view and partially sectioned.
Fig. 1 presents a diagrammatic and simplified view of an elevator car 2 having stopped in the elevator shaft 1 at a position somewhat above the lowest landing floor 4. In the doorway, the gap opening into the elevator shaft between the lower edge of the elevator car and the landing floor 4 is covered by telescoping toe guard 3 extending downwards from the front edge of the elevator car 2 and having a total height larger than the height of the pit 5 of the elevator shaft. Thus, people getting out of the elevator car having stopped in an exceptional position can not fall accidentally into the elevator shaft. On the bottom floor, such a fall is not as dangerous as in a similar situation on upper floors.
Figures 2 and 3 present a toe guard 3 according to the invention as seen from behind, i.e. from the direction of the elevator shaft, and from one side and partially sectioned. An upper part 6 fixedly attached to the front edge of the elevator car 2 extends directly downwards from the front edge of the elevator car. At the lower edge of the planar front plate 11 of the upper part 6 is a fold turned obliquely inwards, i.e. towards the lower part 9. Similarly, the side edges of the upper part 6 have folds turned inwards substantially perpendicularly to the front plate 11 to form the side walls 12
of the upper part 6. Provided on the inner surface of the side walls 12 are substantially vertical guides 7 for guiding the vertical motion of the lower part 9.
Correspondingly, the lower part 9 consists of a planar front plate 13 and side walls 14 formed by folds turned inwards perpendicularly to the front plate. Provided on the outer surface of the side walls 13 are substantially vertical guide elements 10, such as slide bars or equivalent for controlling the vertical motion of the lower part 9 inside the upper part 6, so that the guide elements 10 are guided by the guides 7 in the upper part 6. In addition, the upper edge of the lower part 9 is provided with a fold 15 oriented in an outward, i.e. forward direction and serving to stop the motion of the lower part against the buffers 8a fastened to the bottom of the upper part 6. Thus, the lower part 9 can not fall down from inside the upper part 6. Moreover, the lower edge of the lower part 9 is provided with one or more buffers 8b serving to dampen the impact on the lower part 9 when the lower part hits the bottom of the elevator shaft .
The inner surface of the lower part 6 is additionally provided with a safety circuit contact 16, the counterpart of which is placed in the upper part of the outer surface of the lower part 9. Except at the lowest landing floor, the safety circuit contact 16 opens and causes a halt of the elevator car 2 if anything touches the lower part 9 of the toe guard 3 so that the lower part slides upwards inside the upper part 6. This may occur e.g. when someone puts a hand or foot into the shaft opening. At the lowest landing floor there is a separate limit switch, which, however, is not depicted in the figures. When the contact 16 is moving past the limit switch, it is shunted , so this allows the elevator car to stop at the correct position at the lowest landing floor even if the shaft pit is so low that the lower part 9 of the toe guard 3 will slide upwards. The shunting also allows the elevator car
to be driven as far down as possible during maintenance.
It is obvious to the person skilled in the art that the invention is not limited to the example described above, but that it may be varied within the scope of the claims presented below. Thus, the toe guard may also be made from more than two telescoping parts. Likewise, a safe toe guard can be made from two or more parts placed side by side which move into their respective upper parts in such manner that only that part moves to which a force is applied from below. This provides the advantage that the opening leading into the shaft remains as well closed as possible, because only a relatively narrow part of the toe guard slides upwards.
It is likewise obvious that the guide elements of the lower part may be rail-like elements or e.g. structures resembling elevator car guide elements . It is also possible to have the guide bars placed in the lower part and the guide elements in the upper part. Moreover, the placement and structural solutions of the safety circuit contact may differ from the above description.