ELEVATOR CUSHIONING DEVICE

BACKGROUND SECTION

[0001] Cushioning units have been proposed that are set in the pit at the lower end of the hoistway to buffer the impact when certain elevator malfunctions occur and the car overshoots the normal stop position at the bottom or top floor so that the car or balance weight strikes the lower end of the hoistway.

[0002] Examples of the cushioning units that have been used in the prior art include the spring-type cushioning unit described in Japanese Kokai Patent Application No.

2000-136075, and the oil-filled cushioning unit described in Japanese Kokai Patent

Application No. Hei 7[1995]-237846.

[0003] These cushioning units are installed on the pit floor facing the car or balance weight. If the car overshoots the normal stop position at the bottom or top floor, the cushioning unit contacts the balance weight so that its downward stroke buffers the impact.

[0004] In order to realize the appropriate cushioning effect with the aforementioned conventional cushioning units, the cushioning unit should have specific cushioning characteristics corresponding to the rated load and rated velocity of the car.

Consequently, it is necessary to prepare and stock various types of cushioning units to meet the specifications of various elevators. As a result, the general applicability of the cushioning unit is poor, and this is unfavorable from the cost standpoint.

SUMMARY OF THE INVENTION

Exemplary embodiments of the invention provide an elevator cushioning device that can improve the general applicability of the cushioning unit so that the cost can be reduced. The elevator cushioning device includes a deformable mechanism having at least two links that are pivotably connected to each other. The deformable mechanism is configured to receive a load from a vertical direction and to translate the load to a ⁴ horizontal direction. A cushioning unit is in operable communication with the

deformable mechanism and the cushioning unit is positioned to receive the load from the horizontal direction.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 illustrates the cushioning device installed in the pit of the elevator in

Embodiment 1. Figure 1 (a) is its front view, and Figure 1 (b) is its plan view.

[0006] Figure 2 is a diagram illustrating the state when the cushioning device shown in

Figure 1 is at the end of its stroke.

[0007] Figure 3 is a diagram illustrating the states before and after the stroke of the cushioning device shown in Figure 1.

[0008] Figure 4 is a graph illustrating the cushioning characteristics of the cushioning device shown in Figure 1 and of the spring-type cushioning unit in the prior art.

[0009] Figure 5 illustrates Embodiment 2. Figure 5(a) is its front view, and Figure 5(b) is the plan view of Figure 5(a).

[0010] Figure 6 illustrates Embodiment 3. Figure 6(a) is its front view, and Figure 6(b) is the plan view of Figure 6(a).

[0011] Figure 7 illustrates Embodiment 4. Figure 7(a) is its front view, and Figure 7(b) is the plan view of Figure 7(a).

[0012] Figure 8 illustrates Embodiment 5. Figure 8(a) is its front view, and Figure 8(b) is the plan view of Figure 8(a).

[0013] Figure 9 illustrates Embodiment 6. Figure 9(a) is its front view, and Figure 9(b) is the plan view of Figure 9(a).

[0014] Figure 10 illustrates Embodiment 7. Figure 10(a) is its front view, and Figure

10(b) is the plan view of Figure 10(a).

[0015] Figure 11 illustrates Embodiment 8. Figure 1 l(a) is its front view, and Figure

1 l(b) is the plan view of Figure I l(a).

DETAILED DESCRIPTION

[0016] Figure 1 illustrates the cushioning device installed in the pit of an elevator as an embodiment of the present invention. Figure l(a) is a front view, and Figure l(b) is a plan view.

[0017] As shown in Figures l(a), (b), a cushioning device 3 is installed on a pit floor 1 at the bottom of the hoistway for cushioning the impact in case a car 2 hits pit floor 1. [0018] In cushioning device 3, two groups of 4-section parallel link mechanisms 5, having nearly a parallelogram (i.e., lozenge) shape overall, are mounted as a multi-section link mechanism on an upper surface of a rectangular base plate 4 on pit floor 1. On an upper part of the two 4-section parallel link mechanisms 5, a metal -impact part 6 is provided as a contact body with a lower part of car 2 and arranged facing the car's cushioning device receiver 2a.

[0019] The two 4-section parallel link mechanisms 5 have a pair of center-folding link mechanisms 7 arranged facing each other. Each of the center-folding link mechanisms 7 has four links 7c with the same length. The four links 7c are arranged in two pairs with each pair of links connected together at a first end with a roller 7b by means of a pin 7d so that the structure can fold at an intermediate connecting part 7a. A top second end of each of the center-folding link mechanisms 7 is pivoted to a plate-side connecting part 4a on the upper surface of base plate 4, and, at the same time, a bottom second end of center-folding link mechanism 7 is pivoted to a metal-impact-part-side connecting part 6a arranged at nearly the center of a lower surface of metal-impact part 6. As a result, 4-section parallel link mechanisms 5 are formed. In these 4-section parallel link mechanisms 5, the lines connecting two intermediate connecting parts 7a are parallel with each other and parallel to pit floor 1. The 4-section parallel link mechanisms 5 are left/right symmetrical with each other.

[0020] On the two end portions of base plate 4, rectangular plate shaped cushioning unit mounts 8 are arranged facing each other. Spring-type cushioning units 9 using coil compression springs are mounted on vertical attachment wall surfaces 8a on the sides of cushioning unit mounts 8 where the two cushioning unit mounts 8 are facing each other, such that the line connecting the two intermediate connecting parts 7a in 4-section

parallel link mechanisms 5 is parallel with the unit's axis. That is, two cushioning units 9 are arranged facing each other with two 4-section parallel link mechanisms 5 sandwiched between them. The tip portions of two cushioning units 9 and rollers 7b of intermediate connecting parts 7a are normally in contact with each other via spring plates 17, respectively. In addition, the back sides of two cushioning unit mounts 8 and the upper surface of base plate 4 are connected to each other via reinforcing plate 10. [0021] Figure 2 is a diagram illustrating the state of impact of car 2 with cushioning device 3 shown in Figure 1. The same part numbers as those adopted in Figure 1 are used in Figure 2.

[0022] When car 2 overshoots the normal stop position at the bottom floor and descends significantly for some reason, cushioning device receiver 2a of car 2 contacts metal-impact part 6 of cushioning device 3. As a result, while metal-impact part 6 is pressed downward together with the downward movement of metal-impact part 6, the two parallel 4-section link mechanisms S are flattened and cause spring cushioning units 9 to deform. That is, in the 4-section parallel link mechanisms 5, .when intermediate connecting parts 7a separate from each other, the two 4-section parallel link mechanisms 5 become flatter. Two cushioning units 9 are compressed via spring plates 17 parallel to pit floor 1 while they make rolling contact with rollers 7b of intermediate connecting parts 7a. The contact portions between the two cushioning units 9 and two rollers 7b act as load input portions and are stroked in the compressive direction in the same way, and a cushioning force is generated in 4-section parallel link mechanisms 5 such that intermediate connecting parts 7a are pressed towards each other to absorb the impact load. Also, when the two cushioning units 9 are stroked in the compressive direction, the two cushioning units 9 are backed up by cushioning unit mounts 8. [0023] Figure 3 is a diagram illustrating 4-section parallel link mechanisms 5 before and after receiving the impact load from car 2. The solid line indicates 4-section parallel link mechanisms 5 before application of the impact load, and the broken, line indicates 4-section parallel link mechanisms 5 after application of the impact load. Also, Figure 4 is a graph illustrating the cushioning characteristics of cushioning device 3 and the spring-type cushioning device of the prior art.

[0024] Here, springs with spring constant k are used as the two cushioning units 9. As shown in Figure 3, each of links 7c that forms 4-section parallel link mechanisms 5 has a link length of Li . Assuming the overall link mechanism width of 4-section parallel link mechanisms 5 when there is no load is L ₂ , when the downward stroke distance of metal- impact part 6 ϊsy, the cushioning force P of the overall cushioning device 3 that presses metal-impact part 6 upward due to the cushioning force of cushioning units 9 is shown in the following formula. Also, the relationship between cushioning force P of cushioning device 3 and stroke distance y is represented by cushioning characteristics line A in Figure 4. On the other hand, the relationship between cushioning force P and stroke distance y of the spring-type cushioning unit in the prior art is represented by cushioning characteristics line B in Figure 4.

[Numeric formula 1]

[0025] As shown in the above formula, cushioning force P of cushioning device 3 depends on link length Li and link mechanism width L ₂ . This is because the magnitude of the force component of the cushioning force of each cushioning unit 9 that acts in the direction to push up metal-impact part 6 against the impact load depends on folding angle θ of center-folding link mechanism 7. That is, when stroke distance^ is increased, compressive deformation occurs in cushioning unit 9, and the cushioning force increases. On the other hand, when folding angle θ becomes smaller, the proportion of the force component of the cushioning force of cushioning unit 9 that acts in the direction to push up metal-impact part 6 becomes smaller, and compared with cushioning characteristics

line B of the spring-type cushioning unit in the prior art, the increase in cushioning force P of the overall cushioning device 3 due to an increased stroke distance y is limited. Also, by selecting link length Li and link mechanism width L ₂ as desired, it is possible to change folding angle θ of each center-folding link mechanism 7 when there is no load, and the cushioning characteristics for the overall cushioning device 3 can be set at will without changing the spring constant k of cushioning unit 9. For example, when link length Li of the cushioning device haλiing the cushioning characteristics of line A is increased, folding angle θ becomes larger, and cushioning force P of the overall cushioning device 3 becomes larger, and the cushioning characteristics change to those illustrated by cushioning characteristics line C.

[0026] Consequently, with the cushioning device of the elevator with this constitution, because it is possible to establish any desired cushioning characteristics for overall cushioning device 3 by selecting link length Li and link mechanism width L ₂ as desired, and without changing the spring constant k of cushioning unit 9, the general applicability of cushioning units 9 is improved, and the cost is reduced.

[0027] Also, because cushioning units 9 are stroked in the direction parallel to pit floor 1, it is possible to reduce the overall height of cushioning device 3, and this leads to smaller pit depth and smaller space in the hoistway. In addition, an increase in stroke distance y can reduce the increase in cushioning force P. Consequently, the force on the passenger in car 2 can be reduced, and the safety of the elevator is improved. [0028] Moreover, while the present embodiment illustrates cushioning device 3 is installed on pit floor 1 so that it faces car 2 ₅ cushing device 3 can also installed on pit floor 1 facing the balance weight so that it comes into contact with the balance weight when car 2 overshoots the normal stop position at the top floor. Also, the spring-type cushioning units can also be replaced by oil-filled cushioning units. [0029] Figures 5-7 illustrate modified examples of the multi-section link mechanism as Embodiments 2-4, respectively. In Figures 5-7, (a) is the front view; in Figures 5-7, (b) is the plan view. In Figures 5-7, the same part numbers are adopted as those adopted in Figure 1.

[0030] Figure 5 is a diagram of a 5-section link mechanism 13 used as the multi-section link mechanism. In this case, a pair of plate-side connection parts 4a is provided on base plate 4, and two center-folding link mechanisms 7 are pivotably connected to base plate 4 at the corresponding plate-side connecting parts 4a, respectively. In this way, 5-section link mechanism 13, with one section essentially being base plate 4, is formed.

[0031] Figure 6 illustrates a 5-section link mechanism 14 is adopted as the multi-section link mechanism. In this case, a pair of metal-impact-part-side connecting parts όa is provided on metal-impact part 6, and because two center-folding link mechanisms 7 are pivotably connected to metal-impact part 6 at metal-impact-part-side connecting parts 6a, respectively, a 5-section link mechanism 14, with one section essentially being metal-impact part 6, is formed.

[0032] Figure 7 illustrates a 6-section link mechanism 16 is adopted as the multi-section link mechanism. In this case, a pair of plate-side connecting parts 4a and metal-impact-part-side connecting parts 6a are provided on base plate 4 and metal-impact part 6, and center-folding link mechanisms 7 are connected to base plate 4 as well as to metal-impact part 6 at plate-side connecting part 4a and metal-impact-part-side connecting part 6a, so that 6-section link mechanism 16, with respective sections essentially being metal-impact part 6 and base plate 4 is formed. [0033] For the cushioning devices 11, 12, 15 with these constitutions, the same cushioning characteristics shown in Figure 4 for cushioning device 3 using 4-section parallel link mechanisms 5 can be obtained, and the same effects as those of cushioning device 3 are realized.

[0034] Figure 8 illustrates Embodiment 5 as a modified example of cushioning units 9 shown in Figure 1. Figure 8(a) is a front view, Figure 8(b) is its plan view. In Figure 8, the same part numbers are adopted as those in Figure 1.

[0035] In this embodiment, cushioning unit 22 using coil tension springs is adopted as the cushioning unit for cushioning device 18. The cushioning unit 22 is arranged between center-folding link mechanisms 7 arranged facing each other, and the two intermediate connecting parts 7a in each 4-section parallel link mechanisms 5 are

connected to each other. More specifically, intermediate connecting parts 7a adjacent in the width direction of base plate 4 are connected to connecting shaft 7e, and the two ends of connecting shaft 7e opposite each other are connected by means of cushioning unit 22. That is, the two ends of both cushioning units 22 and intermediate connecting parts 7a are connected to each other via connecting shaft 7e, respectively.

[0036] With cushioning device 18 having this constitution, when car 2 presses metal- impact part 6 downward, to two intermediate connecting parts 7a of each 4-section parallel link mechanism 5, together with the connecting shafts 7e, are separated from each other and the 4-section parallel link mechanisms 5 flatten out. As a result, the contact portions between the two cushioning units 22 and connecting shaft 7e are taken as load input portions and are displaced in the tensile direction, while a cushioning force is generated in the direction in which the two intermediate connecting parts in 4-section parallel link mechanisms 5 approach each other so that the impact load is absorbed. [0037] Consequently, the cushioning device 18 with this constitution displays the same cushioning characteristics shown in Figure 4 of cushioning device 3 using compressive coil springs as cushioning units 9, and it displays the same effects as cushioning device 3. [0038] Because cushioning units 22 are set between the center-folding link mechanisms 7 in the 4-section parallel link mechanisms 5, cushioning device 18 can be made smaller in the axial direction of cushioning units 22.

[0039] In addition, because the stroke of cushioning units 22 is in the tensile direction, there is no buckling of cushioning units 22, so that the reliability of cushioning device 18 is higher.

[0040] Figures 9-11 illustrate Embodiments 6-8, respectively. In Figures 9-1 1, (a) is a front view. In Figures 9-11, (b) is a plan view. In Figures 9-11, the same part numbers are adopted as those adopted in Figure 8.

[0041] Figure 9 illustrates 5-section link mechanism 13 the multi-section link mechanism in cushioning device 19. Figure 10 illustrates 5-section link mechanism 13 as the multi-section link mechanism in cushioning device 20. Figure 11 illustrates 6-section link mechanism 16 as the multi-section link mechanism in cushioning device 21.

[0042] Cushioning devices 19, 20, 21 with this constitution display the same cushioning characteristics shown in Figure 4 for cushioning device 18 using 4-section parallel link mechanisms 5. Also, they display the same effects as those of cushioning device 18.

[0043] When the car or balance weight hits the lower end of the hoistway, the exemplary cushioning devices described above provide for the downward impact load to be converted by the multi-section link mechanism to be parallel to the pit floor, and to be absorbed by the cushioning unit. Also, because the magnitude of the upward force component of the cushioning unit's cushioning force that faces the impact load depends on the bending angle of the center-folding link mechanism, adjusting the bending angle of each the center- folding link mechanism under no load enables changing the overall cushioning characteristics of the cushioning device.

[0044] More specifically, a pair of cushioning units is arranged facing each other with the multi-section link mechanism sandwiched between them; when the impact load is input from the car or balance weight to the multi-section link mechanism, each the braking unit is stroked in the compressive direction while the impact load is absorbed. [0045J In the cushioning force of the cushioning unit, the force component in the direction facing the impact load depends on the bending angle of each the center-folding link mechanism. Consequently, by setting the bending angle of the intermediate connecting part in the load-free state, it is possible to change the cushioning characteristics of the overall cushioning device without changing the cushioning characteristics of each the cushioning unit, and it is possible to improve the general applicability and to cut the cost.

[0046] While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this

invention, but that the invention will include all embodiments falling within the scope of the appended claims.