HK1191626A - Aisle emergency brake for rail-guided vehicle - Google Patents

Description

Aisle emergency brake for rail-guided vehicles

Cross Reference to Related Applications

This application claims priority to U.S. patent application serial No. 61/471,326, filed on 4/2011, which is incorporated herein by reference in its entirety.

Background

The present invention relates to an emergency brake for a vehicle, and in particular to an emergency brake that prevents a track-guided vehicle from inadvertently passing outside its normal operating aisle. Although the invention is particularly useful for shuttle vehicles used in automated stereoscopic warehouses, it may find application in other track guided vehicles as well.

In the case of automated vehicles operating in an automated stereoscopic warehouse, it is possible that the vehicle inadvertently exits its intended travel space. While such exit may occur under a variety of conditions, it is more likely to occur when the automated warehouse is programmed.

Disclosure of Invention

The present invention provides a reliable and relatively inexpensive aisle emergency brake for a track-guided vehicle. Although the operating speed of modern vehicles has increased considerably, it also enables positive vehicle stopping. This increase in operating speed greatly increases the kinetic energy of the moving vehicle and, therefore, increases the difficulty of stopping the vehicle. The present invention uses the kinetic energy of the vehicle to stop the vehicle, rather than the energy stored in the tensioner or the like.

In accordance with an aspect of the present invention, an aisle emergency brake system for a vehicle adapted to travel on at least one track includes a brake assembly and a stop assembly adapted to stop the vehicle when engaged with each other. The stop assembly is mounted on the track if the brake assembly is mounted on a vehicle or on the track if the stop assembly is mounted on a vehicle. The brake assembly includes a biasing mechanism and a pair of brake pads. The pair of brake pads are spaced apart by a nominal operating distance and face each other in a facing direction. The biasing mechanism biases the brake pads toward each other to the operating distance. The stop assembly includes a body defining two surfaces. Both surfaces face outwardly and have stops that are spaced apart a distance greater than the operating distance of the brake pad.

Both surfaces may have centering portions which are inclined towards each other. The centering portion initially engages the brake pad and centers the brake pad in the facing direction. The brake pads may be spaced apart by a biasing distance when the biasing mechanism is compressed by the stop, and the two surfaces may also have end stops that are at least partially spaced apart by a distance greater than the biasing distance to prevent the brake assembly from passing the stop assembly. One of the brake pads may be fixedly mounted and a biasing mechanism biases another of the brake pads toward the fixed brake pad. The biasing mechanism may be comprised of a plurality of belleville washers. The bracket may be configured to mount the brake pad and the biasing mechanism. A self-centering mount may be provided that holds the carriage at the vehicle or rail in a manner that allows the carriage to move in a facing direction. The self-centering mount may be comprised of a shaft and at least one aperture surrounding the shaft. The opening is elongated in the facing direction. The self-centering mount may allow the bracket to pivot about the aperture and the shaft to allow the brake assembly to move from an operating position, in which the brake assembly will engage the stop assembly, to a non-operating position. At least one torsion biasing member may be provided to bias the brake assembly into the operating position. The at least one torsion biasing member may be comprised of a plurality of torsion springs to provide redundancy.

The brake pad and the stop assembly may both be made of aluminum, or one may be made of aluminum and the other of steel to define a high friction engagement. The disengagement tool may be arranged to disengage the brake assembly from the stop assembly. The separation tool compresses the biasing mechanism until the brake pads are separated by more than the biasing distance.

The stop assembly body may include two body portions secured to opposite sides of a planar member having a particular thickness. The brake pad has an operating distance greater than the specified thickness of the planar member.

These and other objects, advantages and features of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings.

Drawings

FIG. 1 is a perspective view of a brake assembly mounted on a track-guided vehicle according to an embodiment of the present invention;

FIG. 2 is the same view as FIG. 1, showing additional details of the brake assembly;

FIG. 3 is a perspective view of the stop assembly mounted on a track on which the vehicle travels;

FIG. 4 is a top plan view of the aisle emergency brake system showing the brake assembly in two positions relative to the stop assembly;

FIG. 5 is a sectional view taken along line V-V in FIG. 4;

FIG. 6 is a sectional view taken along line VI-VI in FIG. 4;

FIG. 7 is an end view showing movement of the brake assembly from the operating position to the non-operating position; and

fig. 8 is an end view showing the operation of the separation tool.

Detailed Description

Referring now to the drawings and the exemplary embodiments depicted therein, a aisle emergency brake system 10 is provided for a vehicle 12 adapted to travel on one or more tracks 14. The braking system 10 includes a brake assembly 16 and a stop assembly 18, the brake assembly 16 and the stop assembly 18 being adapted to stop the vehicle 12 when engaged with one another. The braking system 10 is an emergency braking system that is used to prevent damage if the vehicle 12 inadvertently pushes past the end of its predetermined travel space, such as a passageway in an automated storage facility, such as the type disclosed in commonly assigned U.S. patent application publication nos. 2011/0008137a1 and 2011/0008138a1, the disclosures of which are incorporated herein by reference. The braking system 10 may be useful during normal operation start-up or maintenance of an automated warehouse.

The brake assembly 16 is shown mounted at the vehicle 12, while the stop assembly is mounted at the track 14. However, it should be understood that the brake assembly may be mounted on the track, while the stop assembly is mounted on the vehicle.

The brake assembly 16 is comprised of a carrier 20, a pair of brake pads 22a, 22b, and a biasing mechanism 24 (fig. 2) mounted on the carrier 20. Brake pads 22a, 22b are spaced apart a nominal operating distance OD and face each other in a facing direction (fig. 4). The biasing mechanism 24 biases the brake pads 20a, 20b toward each other to an operating distance OD. As shown in fig. 4 and 6 and as will be discussed below, the brake pads 20a, 20b are separated to a biasing distance BD when the biasing mechanism 24 is compressed under emergency operation of the brake system. Self-centering mount 26 retains bracket 20 on vehicle 12 in a manner that allows limited movement of bracket 20 in the brake pad facing direction.

The stop assembly 18 includes a body 27, the body 27 defining two outwardly facing surfaces 28 (fig. 3). The surfaces 28 each have a plurality of stops 30, the stops 30 being spaced apart a distance greater than the operating distance OD of the brake pads 22a, 22b and less than the offset distance BD. The surface 38 also has a plurality of centering portions 32, the centering portions 32 being angled toward one another in a direction facing toward the brake assembly 16. The purpose of the centering portion 32 is to initially engage the brake pads 22a, 22b and center the brake pads in the facing direction when the self-centering mount 26 allows movement of the carrier 20 in that direction. This ensures that a substantially equal stopping pressure is applied between each brake pad 22a, 22b and the stop 30 of its associated surface 28. The surface 28 also has end stops 34, the end stops 34 tapering outwardly from the stops 30 where they are spaced apart by more than the brake pad biasing distance BD to prevent the brake assembly 16 from passing the stop assembly 18 if the brake system 10 is not able to operate in its intended manner. The body 27 is divided into two portions 27a, 27b which are secured, for example by rivets or the like, to opposite sides of a planar member 52, the planar member 52 constituting part of the track 14. The brake pads 22a, 22b have an operating distance OD greater than the thickness of the planar member 52 such that the brake pads are not in contact with the planar member 52. If the vehicle 12 has a horizontal guide roller (not shown) on one side thereof engaging one of the rails 14, the stop assembly 18 will be mounted to the other rail 14 without engaging the horizontal guide roller to avoid engagement between the horizontal guide roller and the stop assembly 18.

Brake pad 22a is fixedly mounted on bracket 20, and biasing mechanism 24 biases brake pad 22b toward brake pad 22 a. This is possible because the combination of the self-centering mounting portion 26 and the surface 28 configuration repositions the brake pads 22a, 22b to exert substantially the same stopping force. In the illustrated embodiment, the biasing mechanism 24 is comprised of a plurality of Belleville washers 36. As is known in the art, belleville washers are capable of providing a large amount of biasing force over a relatively short distance. Such gaskets are commercially available from a variety of sources. The self-centering mount 26 consists of a mounting shaft 38 and two openings 40 in the bracket 20 around the shaft 38. The apertures 40 are elongated in the facing direction of the brake pad to allow limited movement of the carrier 20 in the facing direction for self-centering of the brake pad.

As shown in FIG. 7, the self-centering mount 26 also allows the bracket 20 to pivot about the aperture 40 and the shaft 38 to allow the brake assembly 16 to move from an operating position, in which the brake assembly will engage the stop assembly, to a non-operating position. At least one torsion biasing member 42 is provided to bias the brake assembly 16 to the operating position. In the illustrated embodiment, the at least one torsional biasing member is a plurality of torsion springs 44, each torsion spring 44 operating on a portion of the bracket 20. This provides redundancy so that the brake assembly 16 will remain in its operating position even if one of the torsion springs 44 fails. While the illustrated embodiment contemplates that the brake assembly 16 will be manually pivotally displaced, such as by a technician, to either disable the vehicle 12 or to bring the vehicle 12 back into service, an optional motor (not shown) may be provided to allow the brake assembly to be pivoted away from service in a conventional manner by a motor operated in accordance with commands from a controller (not shown) to allow the vehicle to exit its normal operating space. This may be useful, for example, in the case of a vehicle leaving its aisle to be maneuvered to an elevator or the like, such as disclosed in the above-referenced commonly assigned U.S. patent application publication No. 2011/0008137.

Because the brake system 10 is intended to be an emergency brake, the brake pads 22a, 22b need not be made of conventional brake pad material, such as the type used in vehicle brakes. The primary criteria is a high friction interface between brake pads 22a, 22b and surface 28. This may be accomplished, for example, by making both the brake pad and the body 27 of the stop assembly 18 from aluminum to produce a coefficient of friction of about 1.0, or by making the brake pad from aluminum while the body 27 is made from steel or other iron-based metal, or making the body 27 from aluminum while the brake pad is made from steel or other iron-based metal to define a high friction engagement. Other examples will be apparent to those skilled in the art.

A disengagement tool 46 may be provided to disengage the brake assembly 16 from the stop assembly 18. The separation tool 46 includes a rod portion 48, the rod portion 48 compressing the biasing mechanism 24 until the brake pads 22a, 22b are separated beyond the biasing distance BD so that the vehicle can slide out of the stop assembly. The separation tool 46 also includes a handle portion 50, which handle portion 50 can be gripped by a technician and pivoted in the manner shown in fig. 8 to leverage the shaft portion 48. Leverage can be enhanced by making the handle portion 50 significantly longer than the stem portion 48.

Changes and modifications in the specifically described embodiments of the invention may be carried out without departing from the principles of the invention, which is intended to be limited only by the scope of the appended claims, as interpreted according to the principles of patent law including the doctrine of equivalents.

Claims (17)

1. An aisle emergency brake system for a vehicle adapted to travel on at least one track, the brake system comprising:

a brake assembly and a stop assembly adapted to stop the vehicle when engaged with each other, the brake assembly adapted to be mounted on a selected one of the vehicle and the at least one track, the stop assembly adapted to be mounted on a selected other of the vehicle and the at least one track;

the brake assembly includes a pair of brake pads spaced apart a nominal operating distance and facing each other in a facing direction, and a biasing mechanism adapted to bias the brake pads toward each other to the operating distance; and is

The stop assembly includes a body defining two surfaces, each facing outward, and each having a stop portion spaced apart a distance greater than an operating distance of the brake pad.

2. The brake system as defined in claim 1, wherein the two surfaces each have a centering portion that is angled toward each other, the centering portions adapted to initially engage the brake pad and center the brake pad in the facing direction.

3. The braking system of claim 2, wherein the brake pad is spaced apart by a biasing distance when the biasing mechanism is compressed by the stop, the two surfaces each having an end stop that is at least partially spaced apart by a distance greater than the biasing distance to prevent the brake assembly from passing the stop assembly.

4. The braking system of claim 1, wherein the brake pad is spaced apart by a biasing distance when the biasing mechanism is compressed by the stop, the two surfaces each having an end stop that is at least partially spaced apart by a distance greater than the biasing distance to prevent the brake assembly from passing the stop assembly.

5. The braking system of claim 1, wherein one of the brake pads is fixedly mounted and the biasing mechanism biases another of the brake pads toward the one of the brake pads.

6. The braking system of claim 1, wherein the biasing mechanism includes a plurality of belleville washers.

7. The braking system of claim 1, comprising a bracket supporting the brake pad and the biasing mechanism and a self-centering mount adapted to retain the bracket at the selected one of the vehicle and the at least one rail in a manner that allows the bracket to move in the facing direction.

8. The braking system of claim 7, wherein the self-centering mount includes an axle and at least one aperture surrounding the axle, the at least one aperture being elongated in the facing direction.

9. The braking system of claim 8, wherein the self-centering mount allows the bracket to pivot about the at least one aperture and the shaft to allow the brake assembly to move from an operating position in which the brake assembly will engage the stop assembly to a non-operating position.

10. The braking system of claim 7, wherein the self-centering mount allows the bracket to pivot about the at least one aperture and the shaft to allow the brake assembly to move from an operating position in which the brake assembly will engage the stop assembly to a non-operating position.

11. The braking system of claim 10, comprising at least one torsional biasing member adapted to bias the brake assembly to the operating position.

12. The braking system of claim 11, wherein the at least one torsional biasing member includes a plurality of torsion springs to provide redundancy.

13. The brake system as recited in claim 1, wherein a selected one of the brake pad and the stop assembly body is made of aluminum and the other of the brake pad and the stop assembly is made of aluminum or steel to define a high friction engagement.

14. The braking system of claim 1, including a disengagement tool adapted to disengage the brake assembly from the stop assembly.

15. The braking system of claim 14, wherein the separation tool compresses the biasing mechanism until the brake pads are separated by a distance that exceeds the biasing distance.

16. The braking system of claim 1, wherein the stop assembly body includes two body portions secured to opposite sides of a planar member having a particular thickness, and wherein the operating distance of the brake pad is greater than the particular thickness.

17. The braking system of claim 1, wherein the brake assembly is adapted to be mounted at the vehicle and the stop assembly is adapted to be mounted at the track.