Elevator car with electronic safety actuator

Abstract

An elevator car (2, 2′), includes a first safety brake (8, 8′), including a first electronic safety actuator (512, 612), the first safety brake (8, 8′) positioned on a first side of the elevator car (2, 2′) at a first height (20, 20′); and a second safety brake (10, 10′), including a second electronic safety actuator (512, 612), the second safety brake (10, 10′) positioned on a second side of the elevator car (2, 2′) at a second height (22, 22′); the first height is different to the second height.

Claims

1. An elevator system (1), comprising: an elevator car (2) including: a first safety brake (8, 8′), comprising a first electronic safety actuator (512, 612), wherein the first safety brake (8, 8′) is positioned on a first side of the elevator car (2, 2′) at a first height (20, 20′); and a second safety brake (10, 10′), comprising a second electronic safety actuator (512, 612), wherein the second safety brake (10, 10′) is positioned on a second side of the elevator car (2, 2′) at a second height (22, 22′); wherein the first height is different to the second height; a hoistway (4); a first guide rail (6a), located on a first side of the hoistway (4); a second guide rail (6b), located on a second, opposite side of the hoistway (4); wherein the elevator car (2) is arranged to travel along the hoistway (4) on the guide rails (6a, 6b) and wherein the first safety brake (8) and the second safety brake (10) each comprise a respective braking portion (514, 614), configured to engage with the respective first and second guide rails (6a, 6b) to brake motion of the elevator car (2); an elevator system component (16) positioned on the first side of the hoistway (4) at the top or bottom of the hoistway (4), wherein the first side of the elevator car (2) is adjacent to the first side of the hoistway (4); wherein the elevator car (2) has a vertical overlap with the elevator system component (16) when the elevator car (2) is in its uppermost or lowermost position within the hoistway (4); and wherein the first height (20) is such that the first safety brake (8, 8′) is positioned between the elevator system component (16) and a vertical mid-height of the hoistway (4) when the elevator car (2) and the elevator system component (16) are vertically overlapped such that no safety brake is positioned at the same height as the elevator system component (16) when the elevator car (2) is in its uppermost or lowermost position within the hoistway (4).

2. An elevator system as claimed in claim 1, wherein the first height (20) is located within a central region of the overall height of the elevator car (2).

3. An elevator system as claimed in claim 1, wherein the second height (22) is at the top of the elevator car.

4. An elevator system as claimed in claim 1, further comprising an access panel (30), wherein the car panel (30) is positioned such that the first safety brake (8) is accessible from an interior of the elevator car (2) when the car panel is opened.

5. An elevator system as claimed in claim 1, wherein the first height (20, 20′) and the second height (22, 22′) are separated by a height (32, 32′) of at least 1 metre.

6. An elevator system as claimed in claim 1, wherein the first height (20) and the second height (22) are both located in an upper half of the elevator car.

7. An elevator system as claimed in claim 1, wherein the first height (20′) and the second height (22′) are both located in the lower third of the elevator car (2′).

8. An elevator system as claimed in claim 1, wherein the first safety brake (8, 8′) comprises a first braking portion (514, 614) and the second safety brake comprises a second braking portion (514, 614), the braking portions configured to brake motion of the elevator car (2, 2′), wherein at least one of the first braking portion (614) and the second braking portion (614) is an asymmetric brake.

9. An elevator system as claimed in claim 1, further comprising: a first guide element (26, 26′), positioned on the first side of the elevator car (2, 2′) at a first guide element height (27, 27′); and a second guide element (28, 28′), positioned on the second side of the elevator car (2, 2′) at a second guide element height (29, 29′); wherein the first guide element height (27, 27′) is different to the second guide element height (29, 29′).

10. An elevator system as claimed in claim 9, wherein the first guide element (26) is located in proximity to the first safety brake (8) and wherein the second guide element (28) is located in proximity to the second safety brake (10).

11. An elevator system (1) as claimed in claim 1, further comprising at least one sensor (24), arranged to send an electronic signal to each of the first safety brake (8, 8′) and the second safety brake (10, 10′), to trigger the respective braking portions (514, 614) to engage with the respective first and second guide rails (6a, 6b).

12. An elevator system (1) as claimed in claim 1, wherein the elevator system (1) is a machine-room-less elevator system.

Description

DRAWING DESCRIPTION

(1) Certain preferred examples of this disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

(2) FIG. 1 shows a schematic drawing of an elevator system according to the prior art;

(3) FIG. 2 shows a schematic drawing of an elevator system according to a first example of a second aspect of the present disclosure;

(4) FIG. 3 shows a front view of the elevator car shown in FIG. 2;

(5) FIG. 4 shows a front view of an elevator car according to a second example of a first aspect of the present disclosure;

(6) FIG. 5 shows a cutaway side view of a symmetrical safety brake, which may provide the safety brake according to this disclosure; and

(7) FIG. 6 shows a cutaway side view of an asymmetrical safety brake, which may provide the safety brake according to this disclosure.

DETAILED DESCRIPTION

(8) FIG. 1 shows an elevator system 101 according to the prior art. The elevator system 101 includes an elevator car 102 which is arranged to travel within a hoistway 104. The elevator car 102 travels along a first guide rail 106a, which is located on a first side of the hoistway 104, and a second guide rail 106b, which is located on a second, opposite side of the hoistway 104.

(9) The elevator car 102 includes a frame with two uprights 103a, 103b and a cabin 105 mounted to the frame 103a, 103b. A first safety brake 108 is positioned on a first side of the elevator car 102 (e.g., on the upright 103a) and a second safety brake 110 is positioned on a second side of the elevator car 102 (e.g., on the upright 103b). In this known elevator car 102, the first safety brake 108 and the second safety brake 110 are located at the same height at the top of the elevator car 102.

(10) The elevator car 102 is connected to a counterweight 112 by one or more tension members 114. The tension member is driven by a machine 116 to drive motion of the elevator car 102 and the counterweight 112. As the machine 116 drives the elevator car 102 up towards the top of the hoistway 104, the first safety device 108 will move towards the machine 116. This creates a collision zone 118 in which the elevator car 102 is prevented from moving any further up the hoistway 104 due to a risk of the first safety device 108 contacting the machine 116. As a result, space at the top of the hoistway 104 is wasted, and the hoistway must be made taller in order to allow the elevator car 102 to reach a desired height.

(11) FIG. 2 shows an elevator system 1 according to the present disclosure. The elevator system 1 includes an elevator car 2 which is arranged to travel within a hoistway 4. The elevator car 2 travels along a first guide rail 6a, which is located on a first side of the hoistway 4, and a second guide rail 6b, which is located on a second, opposite side of the hoistway 4.

(12) The elevator car 2 includes a first safety brake 8, positioned on a first side of the elevator car 2. The first side of the elevator car 2 is adjacent to the first side of the hoistway 4. The first safety brake 8 is located at a first height 20. In this example the first height 20 is in the mid-region of the height of the elevator car 2, i.e. within the central three-quarters of the overall height of the elevator car 2.

(13) The elevator car 2 also includes a second safety brake 10 positioned on a second side of the elevator car 2. The second side of the elevator car 2 is adjacent to the second side of the hoistway 4. The second safety brake 10 is located at a second height 22, where the second height 22 is different (and in this example higher) than the first height 20.

(14) The elevator car 2 is connected to a counterweight 12 by one or more tension members 14. The tension member 14 is driven by a machine 16 to drive motion of the elevator car 2 and the counterweight 12. The machine 16 is one example of an elevator system component. As a result of locating the first safety brake 8 at a first height 20 which is in the mid-region of the height of the elevator car 2, the elevator car 2 can be driven all the way to the top of the guide rails 6a, 6b without any risk of the first safety brake 8 colliding with the machine 16. Thus the overhead space required in the hoistway 4 above the elevator car 2 can be reduced.

(15) The elevator system 1 includes an electronic over-speed sensor 24, mounted on the elevator car 2, and arranged to trigger engagement of each of the safety brakes 8, 10, if an over-speed of the elevator car 2 is detected. For example, the electronic over-speed sensor 24 may send an electronic signal to an electronic board which commands triggering of the safety brakes 8, 10. Thus the safety brakes 8, 10 are electronic safety brakes. In one example, the electronic over-speed sensor 24 may be arranged to read signals from the hoistway (e.g. on a stationary element mounted in the hoistway, e.g. markings or other detectable areas on a tape or rail in the hoistway).

(16) FIG. 3 shows the elevator car 2 of FIG. 2 in greater detail.

(17) It can be seen that the elevator car 2 in FIG. 3 further includes a first guide element 26, located in proximity to the first safety brake 8 (i.e., close to the first height 20) at a first guide element height 27 and a second guide element 28, located in proximity to the second safety brake 10 (i.e., close to the second height 22), at a second guide element height 29. In this particular example the first guide element 26 and the second guide element 28 are guide shoes. The guide elements 26, 28 attach to the elevator car 2 and help it to run up and down the guide rails 6a, 6b when it travels within the hoistway 4. Guide elements 26, 28 may slide on the guide rails 6a, 6b or they may have rollers that roll along guide rails 6a, 6b.

(18) Although FIG. 2 only shows a single guide element 26, 28 on each side of the elevator car 2, in many examples there are two guide elements 26, 28 on each side of the elevator car, e.g. an upper guide element 26, 28 and a lower guide element 26, 28. Where there are two guide elements on each side, at least one pair of these guide elements 26, 28, e.g. the upper pair or the lower pair may be positioned adjacent to the first and second safety brakes 8, 10.

(19) The elevator car 2 further includes an access panel 30, which is illustrated schematically, located on the first side of the elevator car 2. The access panel 30 can be opened from the interior of the elevator car 2, e.g., by a maintenance person, and is positioned so that the first safety brake 8 and the first guide element 26 are accessible from an interior of the elevator car 2 when the access panel 30 is opened, allowing easy access for maintenance.

(20) The first height 20 of the first safety brake 8 and the second height 22 of the second safety brake 10 are separated by a certain vertical distance (i.e., height) 32. In this example the distance 32 is approximately 1 m.

(21) The elevator car 2 has a centre of gravity, which is at a height 34 illustrated by a dashed line. It will be understood that this is the approximate centre of gravity of the elevator car during normal or standard usage. It may shift upwards if weight is added to the top of the elevator car above the line 34, e.g. for maintenance, or downwards if a large amount of weight is added inside the elevator car below the line 34. Both of the safety brakes 8, 10 are positioned in an upper half of the elevator car 2. As the centre of gravity 34 is in the lower half of the elevator car 2, both safety brakes 8, 10 are necessarily above the centre of gravity 34. This is advantageous since it helps to prevent any moment or reaction force from acting on the elevator car 2 as a result of the safety brakes 8, 10 applying braking forces at different heights. This is particularly beneficial when the safety brakes 8, 10 include a braking portion which is asymmetrical, as discussed further below.

(22) FIG. 4 shows an alternative elevator car 2′, according to a second example of the present disclosure. Like components of the elevator car 2′ are labelled with the same reference numerals used for the elevator car 2 of FIG. 3, but followed by an apostrophe, for example 2 in FIG. 3 is labelled as 2′ in FIG. 4. The elevator car 2′ includes a first safety brake 8′, located at a first height 20′, and a second safety brake 10′ located at a second, different height 22′.

(23) In this example the first height 20′ is approximately one quarter of the height of the elevator car 2′ above the bottom of the elevator car 1, whilst the second height 22′ is located at the bottom of the elevator car 2′. The first height 20′ of the first safety brake 8′ and the second height 22′ of the second safety brake 10′ are separated by a distance 32′ of approximately 50 cm.

(24) The elevator car 2′ has a centre of gravity, which is at a height 34′ illustrated by a dashed line. It will be understood that this is the approximate centre of gravity of the elevator car 2′ during normal or standard usage. It may shift upwards if weight is added above the line 34′, e.g. to the top of the elevator car for maintenance, or downwards if a large amount of weight is added inside the elevator car below the line 34′. Both of the safety brakes 8′, 10′ are positioned in the lower third of the elevator car, and are both below the centre of gravity 34′. This is advantageous since it helps to prevent any moment or reaction force from acting on the elevator car 2′ as a result of the safety brakes 8′, 10′ applying braking forces at different heights. This is particularly beneficial when the safety brakes 8′ 10′ include a braking portion which is asymmetrical, as discussed further below.

(25) It can be seen that the elevator car 2′ in FIG. 4 further includes a first guide element 26′, located in proximity to the first safety brake 8′ (i.e., close to the first height 20′) at a first guide element height 27′ and a second guide element 28′, located in proximity to the second safety brake 10′ (i.e., close to the second height 22′), at a second guide element height 29′. In this particular example the first guide element 26′ and the second guide element 28′ are guide shoes. The guide elements 26′, 28′ attach to the elevator car 2′ and help it to run up and down the guide rails 6a′, 6b′ when it travels within the hoistway 4′. Guide elements 26′, 28′ may slide on the guide rails 6a′, 6b′ or they may have rollers that roll along guide rails 6a′, 6b′.

(26) The safety brakes 8, 10, 8′, 10′ may, for example, be of the types illustrated in either of FIGS. 5 and 6. In this example the safety brakes are both of the same type (i.e., either both asymmetrical or both symmetrical).

(27) FIG. 5 shows a symmetric safety brake 510, including an electronic safety actuator 512 and a braking portion 514. The safety brake 510 is arranged symmetrically on either side of the guide rail 6a, 6b. The operation of only one side of the safety brake 510 will be described, but it will be understood that this process will occur simultaneously on each side of the safety brake 510. The electronic safety actuator 512 includes an electromagnetic component 516 and a magnetic portion 518. The magnetic portion 518 is biased by springs 550 either towards or away from the electromagnet 516. When the electromagnet 516 receives an appropriate electronic signal it energises or de-energises (depending on the biasing of the springs), so as to drive the magnetic portion 518 towards the guide rail 6a, 6b, either by magnetic forces acting against the biasing force of the springs 550, or by the biasing force of the springs 550 no longer resisted by a magnetic force.

(28) The magnetic portion 518 contacts a wedge portion 522 of the braking portion 514 via rollers 552. As a result of this contact the magnetic portion 518 slides the wedge portion 522, along an angled surface of the magnetic portion 518, moving the wedge portion 522 upwards, against the biasing of another spring 554, and also towards the guide rail 6a, 6b. This occurs on either side of the guide rail 6a, 6b so that wedge portions 522 on both sides of the guide rail 6a, 6b will contact the guide rail 6a, 6b simultaneously, and symmetrically, to brake on both surfaces of the guide rail 6a, 6b. This type of safety brake 510 (or specifically the braking portion 514) is therefore referred to as “symmetrical”.

(29) FIG. 6 shows an asymmetric safety brake 610, including an electronic safety actuator 612 and a braking portion 614. The electronic safety actuator 612 includes an electromagnetic component 616 and a magnetic brake 618. The magnetic brake 618 is selectively deployed by operation of the electromagnetic component 616 to contact the guide rail 6a, 6b, and is shown in FIG. 6 in the deployed position where it has moved away from the electromagnetic component 616 and contacts the guide rail 6a, 6b.

(30) As a result of engaging the guide rail 6a, 6b, during movement of the elevator car 2, 2′, the magnetic brake 618 is moved upward with the guide rail 6a, 6b relative to the descending elevator car 2, 2′. The electronic safety actuator 612 is operably coupled to a wedge-shaped portion 622 by a rod or linkage bar 620. The magnetic brake 618, in the rail-engaging position, pushes the wedge-shaped portion 622 in an upward direction due to the relative upward movement of the magnetic brake 618 relative to the descending elevator car 2, 2′ and fixed brake portion 614 which is fixed to the elevator car 2, 2′. This upward motion slides the wedge-shaped portion 622 along an angled interior surface of the fixed brake portion 614 until safety brake pad 624 contacts the guide rail 6a, 6b. Then further upward motion draws the fixed brake portion 614 over to the right (from the perspective of FIG. 6), so that a safety brake pad 625 engages with the guide rail 6a, 6b. Since there is only movement of one wedge-shaped portion, towards one side of the guide rail 6a, 6b, and as contact occurs first on one side only, then later on the opposite side, this type of safety brake 610 is referred to as “asymmetrical”.

(31) As an alternative to the symmetric arrangement shown in FIG. 5, an alternative symmetric brake arrangement could be provided which is similar to the brake shown in FIG. 6, but further including an internal interlocking element, which is arranged so that the two wedges or braking elements move in synchronicity. It will of course be appreciated that many other symmetrical and asymmetrical braking arrangements are possible.

(32) It will be appreciated that the specific forms of brakes shown in FIGS. 5 and 6 are merely be way of illustration of the two types of brake and that many other symmetrical and asymmetrical brake arrangements are known and can be used here instead.

(33) It will be appreciated by those skilled in the art that the disclosure has been illustrated by describing one or more specific aspects thereof, but is not limited to these aspects; many variations and modifications are possible, within the scope of the accompanying claims.