A SHEET METAL BASE PANEL FOR USE IN ELEVATORS

Abstract

A sheet metal base panel for use in elevators is disclosed wherein the said base panel is made from sheet metal of low thickness without compromising its structural integrity, by a specialised hemming process. The said base panel is constructed from a single sheet of metal and incorporates the top and bottom header to form a unitary component. The construction is such that the headers can be positioned either way and hence possesses rotational symmetry which enables in easier installation. This is achieved by a special bending of the base panel on all edges of both the top side and bottom side, four times—a first 90° bending (1a) followed by a second 90° bending (1b), a third 90° bending (1c) and a fourth 180° hemming (1d) of the open edge formed after the third 90° bending (1c).

Claims

1. A sheet metal base panel for use in elevators, the said sheet metal base panel comprising of a single main body (1) having top side, bottom side, left side, and right side, wherein edges of both the top side and bottom side of the said main body (1) are given a first 90° bending (1a) followed by a second 90° bending (1b) and a subsequent third 90° bending (1c) which forms an open edge that is subsequently hemmed in by 180° (1d) respectively.

2. The sheet metal base panel for use in elevators as claimed in claim 1, wherein the sheet metal base panel contains at least a pair of holes (1e, 1f) symmetric to each other, on the top side and bottom side respectively of the main body (1).

3. The sheet metal base panel for use in elevators as claimed in claim 1 or 2, wherein the sheet metal base panel contains at least a pair of stiffeners (2) attached to rear side of the said main body (1).

4. The sheet metal base panel for use in elevators as claimed in claim 2, wherein the sheet metal base panel contains a bracket (3) and shoe (4) arrangement fixed to the main body (1) at the said pair of holes (1f) at one end of the said main body (1), the said end forming the bottom header.

5. The sheet metal base panel for use in elevators as claimed in claim 3, wherein the stiffeners (2) are arranged in the shape of a cross on the rear side of the main body (1), thereby strengthening the mid-section of the base panel.

6. The sheet metal base panel for use in elevators as claimed in claim 3 or 5, wherein the thickness of the stiffeners (2) is more than the thickness of the base panel.

7. The sheet metal base panel for use in elevators as claimed in any one of the preceding claims, wherein the material of the said base panel is stainless steel.

8. The sheet metal base panel for use in elevators as claimed in any one of claims 1 to 6, wherein the material of the said base panel is mild steel.

9. The sheet metal base panel for use in elevators as claimed in any one of the preceding claims, wherein the said base panel is used in landing doors, car doors and cabin panels of elevators, said landing door being a centre opening type, or a telescopic opening type.

10. A process of manufacturing a sheet metal base panel according to any one of the preceding claims, the said process comprising the steps of: (i) making a first 90° bending (1a) using a standard bending machine, at edges of both the top side and bottom side of the main body (1) of the said sheet metal base panel; (ii) making a second 90° bending (1b) following the said first 90° bending (1a); (iii) making a third 90° bending (1c) following the said second 90° bending (1b); and, (iv) making a 180° hemming (1d) at the open edge formed after the said third 90° bending (1c), using the said standard bending machine; and (v) attaching at least a pair of stiffeners (2) to rear side of the said main body (1) after 180° hemming at the open edge.

11. An elevator comprising a sheet metal base panel according to any one of the claims 1 to 9.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0041] The advantages and features of the present invention will be more readily apparent by persons skilled in the art when considered in reference to the following description and when taken in conjunction with the accompanying drawings listed below.

[0042] FIG. 1 is the rear view of an embodiment of the sheet metal base panel for use in elevators disclosed by the present invention.

[0043] FIG. 2 is the sectional view of the sheet metal base panel for use in elevators disclosed by the present invention.

[0044] FIG. 3 is the enlarged sectional view (section X-X & Y-Y) of the bendings given to edges of the top side and bottom side of the single main body (1) of sheet metal base panel for use in elevators disclosed by the present invention.

[0045] FIG. 4A represents the sheet metal base panel before it is administered the structure disclosed by the present invention.

[0046] FIG. 4B represents the sheet metal base panel after the bendings on all sides as disclosed by the present invention.

[0047] FIG. 5A represents the elevator door panel top interface with the lift mechanism, of an embodiment of the sheet metal base panel disclosed by the present invention, wherein the said base panel is used in the elevator door.

[0048] FIG. 5B represents the elevator door panel bottom interface with the sill, of an embodiment of the sheet metal base panel disclosed by the present invention, wherein the said base panel is used in the elevator door.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

[0049] The following description is presented to enable any person skilled in the art to make and use the invention and is provided in the context of particular applications of the invention and their requirements. The present invention can be configured as follows:

[0050] Construction

[0051] According to a preferred embodiment of the present invention, as shown in FIGS. 1 to 5B, the present invention provides a sheet metal base panel for use in elevators, the said sheet metal base panel comprising of: [0052] (i) a single main body (1) having top side, bottom side, left side, and right side, wherein edges of both the top side and bottom side of the said main body (1) are given a first 90° bending (1a) followed by a second 90° bending (1b) and a subsequent third 90° bending (1c) which forms an open edge that is subsequently hemmed by 180° (1d) respectively; [0053] (ii) at least a pair of holes (1e, 1f) symmetric to each other, on the top side and bottom side respectively of the main body (1); [0054] (iii) at least a pair of stiffeners (2) attached to rear side of the said main body (1); and, [0055] (iv) a bracket (3) and shoe (4) arrangement fixed to the main body (1) at the said pair of holes (1f) at one end of the said main body (1), the said end forming the bottom header.

[0056] In the preferred embodiment of the present invention, the stiffeners (2) are arranged in the shape of a cross on the rear side of the said main body (1), thereby strengthening the mid-section of the base panel.

[0057] In another preferred embodiment of the present invention, the thickness of the stiffeners (2) is more than the thickness of the base panel, contrary to the arrangement in existing elevators.

[0058] In an embodiment of the present invention, the sheet metal base panel disclosed herein is used in the landing door of an elevator.

[0059] In another embodiment of the present invention, the sheet metal base panel disclosed herein is used in the car door of an elevator.

[0060] In an embodiment of the present invention wherein the sheet metal base panel disclosed herein is used in the car door or landing door of an elevator, the said door is of the centre opening type.

[0061] In another embodiment of the present invention wherein the sheet metal base panel disclosed herein is used in the car door or landing door of an elevator, the said door is of the telescopic opening type.

[0062] In yet another embodiment of the present invention, the sheet metal base panel disclosed herein is used in the cabin/car panel of an elevator.

[0063] In an embodiment of the present invention wherein the sheet metal base panel disclosed herein is used in the landing door of an elevator, as shown in FIG. 5A, the said base panel is installed by fastening the top of the main body (1) to the truck plate (6) through two L-brackets (7) i.e. a fastener riveted along with bracket passing through the pair of holes (1e) present on the said base panel. The said truck plate is in turn fastened to the top mechanism of the lift with rollers to move to the sides when the door opens. In the same embodiment, as shown in FIG. 5B, the said base panel is installed by fastening the top of the main body (1) to the bracket (3) passing through the pair of holes (1f) and shoe (4) arrangements are inserted into the sill slot (5) for sliding.

[0064] The above mentioned specific embodiments are provided herein for illustrative purposes only. A person skilled in the art would be able to reproduce and/or apply the said construction in various other ways not expressly mentioned herein, for example, by employing the sheet metal base panel disclosed herein as cabin/car panels. Such constructions will be within the spirit and scope of the present patent specification.

[0065] Working

[0066] It is a well established practice known to any person reasonably skilled in the art that the base panels are always made of sheet metal of uniform thickness throughout the panel. The thickness of the sheet metal is decided based on the strength needed at the weakest point of the panel when subjected to mechanical tests as specified by the standards. Thus the default thickness of the sheet at the weakest point becomes the thickness of the entire panel. Usually, elevator door/car panels have base panel thickness of 0.8 mm and above.

[0067] The novel and inventive structure disclosed by the present invention strengthens the weakest parts of the panels through a process called hemming. This allows the weakest parts of the panel to have a higher thickness while the rest of the panel would be having half the thickness. Therefore, this novel and inventive aspect disclosed by the present invention allows the use of very thin metal sheets whose thickness range from 0.5 mm to 0.7 mm to manufacture sheet metal based component for elevators. This unique aspect thus brings a significant reduction in costs while complying with the structural strengths specified for the sheet metal components used in elevators.

[0068] The two longitudinal sides of the base panel disclosed by the present invention act as the top and bottom header and therefore there is no requirement for separately attaching a top and bottom header like in conventional base panels.

[0069] The novel feature disclosed by the present invention allows for use of sheet metal of thickness as low as ≥0.5 mm to ≤0.7 mm in base panel. The improvement in the existing structure is due to the use of the 180° hemming process across all the open edges of the sides of the base panel. Since the edges are the ones that bear the maximum load in the door, such hemming arrangement ensures a double wall thickness of cross sectional in the edges although the thickness of the sheet metal is only ≥0.5 mm to ≤0.7 mm. Such hemming is found on all four sides of the base panel. The selective strengthening of the weak points i.e., the edges of the base panel, is the reason that a sheet metal of ≥0.5 mm to ≤0.7 mm thickness can be used as input for construction. Since the centre of the door panel only has ≥0.5 mm to ≤0.7 mm thickness, stiffeners of 0.8 mm thickness are used to add structural support to the centre to resist deflection during mechanical tests.

[0070] Using the hemming process, it is possible to assimilate the bottom and upper header components into the construction of the base panel to create a unit component comprising of three components. The structure of the elevator base panel preserves the functionality of the base panel, incorporates the functionality of the upper and bottom header in the same base panel while increasing the strength by 10%. Conventionally 3 different sheets of metal thickness were employed to create the door panel—upper and bottom header, base panel, stiffeners. The thickness of sheet metals used for the headers and the base panels used differ varyingly. The present invention utilizes only one sheet of metal of only one thickness to create a unit component that serves as the base panel, upper header and bottom header.

[0071] The present invention achieves the objects set out in the specification hereinabove by creatively engineering the structure of the elevator sheet metal base panels used in landing door, car door and the car itself. The uniqueness of the base panel structure disclosed by the present invention lies in the following features: [0072] (i) Reduction in the number of components: A conventional elevator door comprises of a base panel (thickness ≥0.8 mm) attached to a top and a bottom header wherein the top and bottom headers are originally separate components. However, the structure of the present invention employs a single base panel, eliminating the two extra components while retaining their functionality. Same logic is applicable to car panels too especially those which cater to loads ≤680 kg. [0073] (ii) Reduction in the thickness of the sheet metal (base panel for elevator doors and cars) in the range of ≥0.5 mm to ≤0.7 mm while maintaining the same structural integrity in order to pass the mechanical tests as specified in the standards by Bureau of Indian Standards (BIS) or any other standards local or international.

[0074] Evaluation of Invention and Test Results

[0075] A mechanical test was performed on the sheet metal base panels disclosed herein according to IS 14665 (Part 4_Sec 6). The following were the dimensions of the tested samples: [0076] Thickness of panels: 0.5 mm [0077] Stiffener thickness: 0.8 mm [0078] Top Frame: 70×40 mm [0079] Side Frame: 90×40 mm [0080] Clear Opening×Clear Height: Centre opening 2 panel-(700×2000 & 800×2000)

[0081] Two samples of the following description were tested: [0082] Sample 1—Centre opening 2 panel—700×2000 full Steel sheet metal (0.5 mm) [0083] Sample 2—Centre opening 2 panel—800×2000 full Steel sheet metal (0.5 mm)

[0084] According to IS 14665 (Part 4_Sec 6), 345N forces perpendicular to 5 cm2 area were applied with a dial gauge with plunger (deformation measurement tool).

[0085] The test criteria are that there should be no plastic deformation and the test should not result in the doors being sprung from their guides.

[0086] The following test results were obtained:

TABLE-US-00001 Location P1 P2 P3 Prototypes Elastic Plastic Elastic Plastic Elastic Plastic Result Sample 1 13.10 0.09 14.61 0.12 14.78 0.10 Passed Sample 2 12.52 0.03 13.89 0.06 14.13 0.04 Passed

[0087] Therefore, the novel and inventive structure disclosed by the present invention to improve sheet metal base panels have been shown to pass the mechanical requirements of IS 14665 (Part 4_Sec 6).

[0088] While there has been shown and described what is considered to be preferred embodiments of the invention, it will, of course, be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention be not limited to the exact forms described and illustrated, but should be constructed to cover all modifications that may fall within the scope of the appended claims.

[0089] Further embodiments may also be obtained by combining two or more dependent claims.

[0090] It will be apparent to those skilled in the art that the objects of this invention have been achieved by providing the above invention. However various changes may be made in the structure of the invention without departing from the concept of the invention. Therefore, the scope of the invention is to be determined by the terminology of the following claims and the legal equivalents thereof