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Title:
AUXILIARY BRAKE SYSTEM FOR PASSENGER CONVEYOR SYSTEMS
Document Type and Number:
WIPO Patent Application WO/2004/071860
Kind Code:
A1
Abstract:
A passenger conveyor system (20) includes an auxiliary brake device (60). A braking belt (62) is selectively urged into engagement with a step chain (30) by an engaging member (72). The braking belt (62) is supported by belt supports (64, 66) in a manner that the belt (62) resists rotation and, therefore, resists further movement of the step chain (30), which prevents further movement of the steps (22) of the passenger conveyor.

Inventors:
HAME MARKUS (DE)
MEYER HELMUT J W (DE)
ENGELKE BERNWARD (DE)
FARGO RICHARD (US)
WIESE HERMANN (DE)
SANSEVERO FRANK (US)
STUFFEL ANDREAS (DE)
Application Number:
PCT/US2003/003675
Publication Date:
August 26, 2004
Filing Date:
February 07, 2003
Export Citation:
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Assignee:
OTIS ELEVATOR COMPAGNY (US)
HAME MARKUS (DE)
MEYER HELMUT J W (DE)
ENGELKE BERNWARD (DE)
FARGO RICHARD (US)
WIESE HERMANN (DE)
SANSEVERO FRANK (US)
STUFFEL ANDREAS (DE)
International Classes:
B60T1/00; B60T13/04; B66B29/00; F16D63/00; F16D65/14; (IPC1-7): B62L5/10; B60T3/00; B60T13/04; F16D51/00; F16D65/36
Foreign References:
US6161674A2000-12-19
US4588065A1986-05-13
US6341683B12002-01-29
US4664247A1987-05-12
Attorney, Agent or Firm:
Gaskey, David J. (Gaskey & Olds P.C., 400 West Maple Road, Suite 35, Birmingham MI, US)
Download PDF:
Claims:
CLAIMS We claim:
1. A brake device for use in a passenger conveyor system that includes a step chain that moves with conveyor steps, comprising: a belt that is adapted to selectively engage the step chain; a plurality of belt supports associated with the belt to resist movement of the belt; and an engaging member that selectively urges the belt into engagement with the step chain to apply a braking force to the step chain.
2. The device of claim 1, wherein the belt has a plurality of teeth on an outer surface of the belt that are adapted to engage corresponding teeth on the step chain.
3. The device of claim 1, wherein the belt supports comprise rotationally fixed disks that are spaced apart and engage an inner surface on the belt such that the disks tension the belt and cooperate with the belt to provide the braking force.
4. The device of claim 1, wherein the belt supports comprise rotatable disks that are spaced apart and engage an inner surface on the belt such that the disks tension the belt and including at least one brake member that applies a braking force to at least one of the disks such that the brake member, disk and the belt cooperate to provide the braking force.
5. The device of claim 1, including a sensor that detects an operative condition of a drive member of the conveyor system and wherein the brake member moves into a position to urge the belt into engagement with the step chain responsive to an indication from the sensor.
6. The device of claim 5, including a biasing member that urges the brake member in a direction to urge the belt into engagement with the step chain and a release mechanism that is responsive to the sensor to selectively release the brake member to move into a position to urge the belt into engagement with the step chain.
7. The device of claim 6, including a linkage coupling the sensor to the release mechanism such that movement of a portion of the sensor triggers the release mechanism to release the brake member.
8. The device of claim 5, wherein the sensor. comprises a rotatable member that moves responsive to an undesired condition of the drive member to provide the indication.
9. A passenger conveyor system, comprising: a plurality of steps; a step chain that moves about a chain loop to cause selective movement of the steps; a drive belt that is adapted to engage the step chain to propel the chain about the chain loop; a braking belt spaced from the drive belt; and an engaging member that selectively urges the braking belt into engagement with the step chain to apply a braking force to the step chain.
10. The system of claim 9, including a sensor that monitors a condition of the drive belt and provides an indication when the engaging member should urge the braking belt into engagement with the step chain.
11. The system of claim 10, wherein the sensor includes a roller and a biasing member urging the roller in a direction toward the drive belt, the biasing member moving the roller laterally into a brake application position under selected conditions to provide the indication.
12. The system of claim 11, including a linkage associated with the braking member and the sensor such that at least a portion of the linkage moves responsive to the lateral movement of the roller and wherein movement of the linkage causes the braking member to move the braking belt into engagement with the step chain.
13. The system of claim 12, including a biasing member that urges the braking member into a position where the braking belt is urged into engagement with the step chain and a release mechanism that controls movement of the braking member responsive to the biasing member and wherein the linkage triggers the release mechanism to permit the biasing member to move the braking member.
14. The system of claim 18, including a drive sheave that moves the drive belt and wherein the sensor comprises a sensor member that selectively moves relative to the drive sheave responsive to relative movement between the drive belt and the step chain.
15. The system of claim 14, wherein rotary movement of the sensor member relative to the drive sheave activates the engaging member.
16. The system of claim 9, wherein the braking belt has a plurality of teeth on an outer surface of the belt that are adapted to engage corresponding teeth on the step chain.
17. The system of claim 9, including a plurality of belt supports associated with the braking belt to prevent movement of the braking belt.
18. The system of claim 17, wherein the belt supports comprise rotationally fixed disks that are spaced apart and engage an inner surface on the braking belt such that the disks tension the braking belt and cooperate with the braking belt to provide the braking force.
19. The system of claim 17, wherein the belt supports comprises rotatable disks that are spaced apart and engage an inner surface on the braking belt such that the disks tension the braking belt and including at least one brake member that applies a braking force to at least one of the disks such that the brake member, the disk and the braking belt cooperate to provide the braking force.
Description:
AUXILIARY BRAKE SYSTEM FOR PASSENGER CONVEYOR SYSTEMS Field of the Invention This invention generally relates to passenger conveyors. More particularly, this invention relates to an auxiliary brake arrangement for passenger conveyor systems.

Description of the Related Art Passenger conveyors such as escalators or moving walkways typically include a plurality of steps or pallets that move in a looped pattern. A drive assembly for moving the steps typically is supported within a building structure underneath the corresponding floor or is otherwise enclosed so that it is hidden from view. Over the years, there has been a desire to move away from overly complicated and large machinery. Those skilled in the art have strived to improve passenger conveyor drive systems to make them easier to incorporate into building structures, less maintenance- intensive and more economical, for example.

In attempting to address these concerns, various proposals have been made.

As new drive arrangements are introduced, traditional control systems, such as brakes, also need modification or improvement. For example, typical codes require an auxiliary brake. Conventional escalator systems have a main drive near the upper landing that includes a rotating shaft with sprockets. A step chain associated with the steps has a positive connection to the main drive shaft. An auxiliary brake has been directly and positively connected to the step band or indirectly connected to any drive member that is positively connected to the step chain. With traditional arrangements, the auxiliary brake typically was placed at the main drive shaft.

With the introduction of new drive systems, such placement of the auxiliary brake is no longer possible. Further, different drive systems introduce different concerns for providing the necessary braking functions. This invention provides an auxiliary brake that facilitates using a drive arrangement that includes components that are unique compared to conventional designs.

SUMMARY OF THE INVENTION In general terms, this invention is an auxiliary brake that is useful with an escalator system that has a drive module including a drive belt that engages the step chain to move the steps.

One brake assembly designed according to this invention includes a braking belt that is adapted to selectively engage the step chain of the conveyor system. Belt supports maintain the braking belt in a position close to the step chain and cooperate with the braking belt such that the braking belt resists movement of the step chain when the braking belt engages the step chain. The brake assembly includes an engaging member that selectively urges the belt into engagement with the step chain to apply a braking force to the step chain.

In one example, the belt supports comprise sheaves that are rotationally fixed.

The tension of the braking belt around the sheaves is set such that the friction between the sheaves and the braking belt resists movement of the belt about the sheaves. In some examples, a selected amount of relative movement between the belt and the sheaves is provided for under selected load conditions. Such an arrangement allows for a rapid, but somewhat gradual stop time when the belt engages the step chain.

In another example, the sheaves are rotatable and brake members are provided to apply a braking force to the sheaves so that rotation of the braking belt and the sheaves is controlled by the braking members.

In one example, the engaging member is spring-loaded toward a position where the engaging member forces the belt into engagement with the step chain. A release mechanism holds off the force of the springs but triggers the brake under selected conditions. In one example, a drive belt monitoring sensor triggers the release mechanism in the event of a failure of the drive belt. In one example, a sensor directly monitors the condition of the drive belt. In another example, the drive belt condition is indirectly measured by other conditions of the escalator system.

The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiments. The drawings that accompany the detailed description can be briefly described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 schematically illustrates an escalator system including a brake assembly designed according to this invention.

Figures 2A and 2B schematically illustrate an example drive module with which the inventive brake assembly can be used.

Figure 3 is a perspective, diagrammatic illustration of one example embodiment of a brake assembly designed according to this invention.

Figure 4 is a side-elevational, partial-cross sectional view of the embodiment of Figure 3.

Figure 5 schematically illustrates selected portions of one example embodiment where braking members are applied to a belt-supporting sheave.

Figure 6 schematically illustrates a belt sensor and brake triggering mechanism designed according to one embodiment of this invention.

Figure 7 is a partial, perspective, diagrammatic illustration of an example belt sensor designed according to this invention.

Figure 8 schematically illustrates another drive belt sensing arrangement and brake triggering mechanism designed according to this invention.

Figures 9A and 9B illustrate another example sensor arrangement useful for detecting a need to activate the inventive brake.

Figure 10 shows another perspective of the example step chain link in Figures 9A and 9B.

Figures 11A and 11B diagrammatically illustrate an example release mechanism useful with a brake assembly designed according to this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Figure 1 shows a passenger conveyor system 20 that includes a plurality of steps 22 that are adapted to carry passengers between landings 24 and 26 in a conventional manner. An escalator is illustrated in Figure 1 as an example passenger conveyor. This invention is equally applicable to moving walkways or other passenger conveyors.

As schematically shown in Figures 1,2A and 2B, the escalator system 20 includes a step chain 30 having a plurality of links 32. The step chain 30 is associated with the steps 22 such that movement of the step chain 30 controls movement of the steps 22.

The escalator system 20 includes a drive module 40 having drive belts 42. An exterior surface 44 on the drive belts 42 includes teeth 46 that cooperate with teeth 34 on the step chain links 32.

One belt 42 is associated with each side of the steps, each of which has an associated step chain 30. The illustrated example includes support structure 48 to position the drive module in the escalator system 20. A drive sheave 50 rotates responsive to a machine 54 (i. e. , a motor and brake). The drive sheave 50 includes outer teeth 56 that cooperate with teeth 57 on an inner side 58 of the drive belt 42. An idler sheave 52 is spaced from the drive sheave 50 and rotates responsive to movement of the belt 42, which is caused by rotation of the drive sheave 50. A controller (not illustrated) controls the machine 54 to provide the desired rotation of the drive sheave 50, which results in rotation of the belt 42 and movement of the step chain 30 to cause the desired movement of the steps 22 between the landings 24 and 26.

A synchronizer bar 59 extends approximately the width of the steps so that drive belts 42 and sets of step chain links 34 associated with the edges of the steps, respectively, move synchronously to provide smooth and reliable operation of the conveyor.

In many circumstances, the brake associated with the machine 54 is adequate to provide the necessary braking force to slow down or stop the steps 22 depending on the needs of a particular situation. This invention provides an auxiliary brake device that is useful for stopping or preventing movement of the steps 22 in the event that the drive module brake is not capable of providing the desired braking force. Example situations where this may occur would be in the event of a machine failure or if the belt 42 were to become damaged or broken such that a braking force applied to the drive sheave 50 is not adequately transmitted to the step chain 30. In one example, the inventive brake device is utilized only in the very unlikely event that both drive belts (i. e. , on each side of the conveyor steps) associated with a drive machine were

broken or so damaged that the belts were no longer capable of driving engagement with the step chain links. The inventive arrangement provides a braking force applied directly to the step chain links without relying on the drive belts or the machine operation.

Figures 1,3 and 4 schematically show one example brake device 60 designed according to this invention. The brake device 60 includes a braking belt 62 that is positioned to normally not contact the step chain links 32. The belt 62 is adapted to engage the step chain links 32 in a manner such that a braking force can be applied to the step chain 30 to prevent further movement of the steps 22.

The illustrated example includes belt supports 64 and 66 that are at opposite ends of a loop established by the belt 62. In this example, the belt supports are sheaves. A brake application mechanism 68 is supported between the belt supports 64 and 66. The belt 62 includes teeth 70 on an outer surface that intermesh with the teeth 34 on the step chain links 32 when an engaging member 72 urges the belt 62 into engagement with the step chain 30. In some examples, the braking belt 62 is manufactured to be the same as the drive belt 42, although their functions are different.

In the illustrated example, a support bracket 74 is rigidly supported relative to structural members 76, which are part of an escalator truss in one example. The illustrated embodiment includes a second bracket member 77 that is directly secured to one of the support members 76 at one end and directly secured to the bracket member 74 at an opposite end. The bracket 74 includes openings (not illustrated) that at least partially receive supporting shafts 78 that are secured at one end to the engaging member 72. The engaging member 72 is urged in a direction away from the support bracket 74 by biasing members 80. In the illustrated example, the biasing members comprise coil springs. A release mechanism 82 holds the engaging member 72 against the bias of the springs 80 to keep the brake device 60 in a non-activated state. When a braking force from the brake device 60 is required, the release mechanism 82 allows the springs 80 to force the engaging member 72 away from the bracket 74 (i. e. , upward according to the drawings) such that the belt 62 is urged into engagement with the step chain links 32.

The braking belt 62 preferably is supported so that it resists rotation and, consequently movement of the step chain links 32 when the belt 62 engages the step chain 30. In one example, the braking force is achieved by supporting the belt 62 on the belt supports 64 and 66 in a manner that tension on the belt 62 causes sufficient friction between the inner surface of the belt and the supports 64 and 66 so that the belt does not rotate around the loop established by the belt.

In one example, the belt supports 64 and 66 are rotationally fixed as illustrated in Figures 3 and 4, mounting blocks 102 and 104 include recesses that establish a circular opening 106 that receives at least a portion of a sheave axle 108. The mounting block 104 is secured to a mounting plate 110 that is, in turn, secured to an appropriate support member 76 associated with the escalator system.

As best appreciated from Figure 4, the illustrated example includes at least one dog 114 that is received between the mounting blocks 102 and 104 and at least partially received into a corresponding recess on the sheave axle 108. The dog 114 prevents rotation of the shaft 108 about its axis. Each shaft 108 is fixed to the corresponding belt support 64,66 such that the support does not rotate relative to the escalator support structural members 76.

In another example, the mounting blocks 102 and 104 are internally splined and at least a portion of the outer surface of the sheave axles 108 is externally splined so that no relative rotation occurs between the shaft 108 and the mounting blocks 102 and 104.

In another example, schematically illustrated in Figure 5, the belt supports 64 and 66 are rotatable relative to the structural support members 76. In this example, brake members 120 are applied to appropriate surfaces on the belt supports 64 and 66 to resist rotation of the supports and, therefore, rotation of the belt 62 about the loop.

An arrangement as shown in Figure 5 allows for controlling the brake force applied to the step chain 30 by controlling the braking force of the brake members 120 applied to the belt supports 64 and 66. Those skilled in the art who have the benefit of this description will be able to select an appropriate arrangement to achieve the desired braking force, which accomplishes a desired deceleration rate to meet the needs of their particular situation.

Figure 6 schematically illustrates one example arrangement for monitoring the condition of the drive belts 42 and triggering the brake device 60 responsive to a determination that at least one belt 42 is not performing as desired. In this example, a sensor 130 includes a roller 132 that is biased into engagement with the inner side of the belt 42. In this example, a coil spring biasing member 134 urges the roller 132 into engagement with the inner surface of the belt 42. In the event that the belt is broken, it will no longer travel about the loop established by the drive sheave 50 and the idler sheave 52. Accordingly, the roller 132 will move outward (i. e. , upward according to the illustration) and move on a linkage 136 as the roller moves in that direction. The linkage 136 is associated with the release mechanism 82 of the brake application portion 68 of the brake device 60. As the roller 132 moves responsive to the absence of the belt 42, the linkage member 136 activates the release mechanism 82 such that the engaging member 72 urges the braking belt 62 into the step chain 30 to apply a braking force. Given this description, those skilled in the art will be able to select appropriate linkage components to achieve the brake application, depending on the particular configuration and the needs of their particular system design. In one example, the linkage 136 comprises rigid link members. In another example the linkage 136 comprises a cable that pulls on an appropriate portion of the release mechanism 82.

Figure 7 shows another example belt sensor 140. In this example, a roller 142 is rotatably supported on a support member 144. A mounting member 146 is secured to a portion of the structural support 48. Shafts 145 extend from one side of the support 144 and are received through openings in the support bracket 146. The support 144 and the roller 142 are urged toward the belt 42 by a biasing member 148, which comprises a coil spring in this example.

Under normal operating conditions, the roller 142 rides along the side surface of the belt 42. If the belt becomes broken, the biasing member 148 urges the roller 142 to the left (according to the drawings). Such movement of the roller and the support bracket 144 activates the release mechanism 82 of the brake device 60.

The examples of Figures 6 and 7 show some possible sensor arrangements for monitoring the condition of the belt 42. In some situations, it may be desirable to monitor not only whether the belt is broken but whether the teeth 46 on the belt 42 are

adequately engaging the teeth 44 in the step chain links 32. It may happen, for example, that the teeth 46 become worn or broken, even though the entire belt 42 is not broken.

Figure 8 schematically illustrates one arrangement for monitoring the condition of the drive belt teeth 46. As known, escalator systems typically include rotary sprockets at the turnaround portions of the step chain near the landings. The illustrated example includes an upper rotary sprocket 122 and a lower rotary sprocket 124. The upper sprocket 122 is associated with the turnaround 126 while the lower sprocket 124 is associated with the turnaround 128. Under normal operating conditions, the driving forces applied by the drive belt 42 on the step chain 30 on both sides of the escalator will maintain a relatively equal amount of play at the turnarounds 126 and 128. There is play because the step chain 30 is longer than the tracks (not illustrated) that guide the chain and steps. As known, the sprockets 122 and 124 are spring biased in a direction to maintain a desired amount of tension on the step chain 30.

In the event that the drive belt 42 is not properly engaging the step chain 30 (i. e. , when the teeth 46 on the belt are worn or broken), the weight of the step chain 30 will tend to move the chain downward responsive to the force of gravity. Under these circumstances, the amount of slack at the turnaround 128 increases as the entire step chain 30 tends to move downward. In this situation, the sprocket 124 moves from a first position shown in Figure 8 to a second position shown in phantom in Figure 9 (to the right in the drawing). Such movement of the sprocket 124 provides an indirect indication of improper cooperation between the drive belt 42 and the step chain 30.

In the illustrated example, the sprocket 124 is associated with a linkage 150 that is also associated with the brake release mechanism 82. Accordingly, as the sprocket 124 moves responsive to shifting of the step chain 30, the linkage 150 causes the release mechanism 82 to activate the brake application portion 68 of the brake device 60. This example provides an arrangement for indirectly monitoring the condition of the belt 42. Such an arrangement is also useful for detecting when the belt 42 is broken. The same downward movement of the step chain 30 will occur if the belt 42 is broken.

Depending on the needs of a particular situation or particular code requirements, it may be desirable to activate or engage the brake device 60 only when both drive belts 42 (i. e. , on both sides of the escalator steps) have failed. In such circumstances, the cooperation between the linkage 150 and the release mechanism 82 preferably is arranged so that the release mechanism 82 responds only when both of the drive belts 42 are not operating to transfer sufficient drive torque to the step chain 30. In one example, the linkage between the release mechanism 82 and the belt condition sensor is arranged so that the brake device 60 is activated only when there is sufficient cooperation between both step chains 30 and both drive belts 42.

The example sensor arrangement of Figures 9A and 9B includes a sensor member 160 associated with the drive sheave 50. The sensor member 160 preferably includes a flange body portion 162 with a plurality of radially extending arm portions 164. In the illustrated example, the sensor member 160 is generally star-shaped.

Under normal operating conditions, the sensor member 160 rotates in unison with the drive pulley 50 and has no effect on step chain movement. When there is a failure in the normal operation of the drive mechanism, however, there is relative movement between the drive pulley 50 and the step chain links 32. Under such circumstances, a portion of at least one of the step chain links 32 engages at least one of the radially extending portions 164 on the sensor member 160. This results in at least some relative movement between the drive pulley 50 and the sensor member 160. Such relative motion between the drive pulley 50 and the sensor member 160 instigates an indication that the drive assembly has failed to operate as normally desired (i. e. , the drive belt teeth are worn or damaged or the entire belt 42 is broken).

One example arrangement that utilizes limited relative movement between the sensor member 160 and the drive pulley 50 is illustrated in Figures 9A and 9B. In this example, the sensor member 160 normally rotates with the drive pulley 50. A synchronization arrangement 170 keeps the two rotating together under normal operating conditions.

The sensor member 160 preferably is initially oriented relative to the drive pulley so that a step member 172, which is a bolt secured to the drive pulley 50 in the illustrated example, is positioned against a support surface 174 within a generally arcuate slot 176 formed on the sensor member 160. The support surface 174

preferably includes a partially rounded contour to stabilize the bolt 172 against the surface 174. The device is shown with the bolt 172 in an end 178 of the slot 176 (and not against the surface 174).

A spring 180 normally biases the sensor member 160 away from the drive pulley 50 in a direction parallel to the axis of rotation of the drive pulley. In the initial normal operating position, the spring 180 operates to assist maintaining the bolt 172 on the support surface 174. The contour of the surface 174 and the bias of the spring 180 preferably are set so that a desired minimal amount of force is required to cause movement of the bolt 172 within the slot 176.

As can be appreciated from Figure 9A, a plurality of the synchronizing arrangements 170 preferably are provided spaced about on the drive pulley 50 and sensor member 160.

When there is relative movement between the step chain links 32 and the drive belt 42, engagement between the sensor member 160 and the step chain links 32 causes relative movement between the drive pulley 50 and the sensor member 160.

Depending on the direction of such relative movement, the bolt 172 becomes removed form the surface 174 such that it slides into one of the ends 178 of the generally arcuate slot 176. Such movement of the bolt 172 within the slot 176 is the result of the relative rotary movement between the drive pulley 50 and the sensor member 160, which occurs when the chain 30 and the belt 42 are not properly engaged.

Once the bolt 172 is in one of the ends 178 of the slot 176, the sensor device is activated to provide an indication of a poor or failed belt condition.

In the illustrated example, the radial projections 164 on the sensor member 160 preferably cooperate with reference surfaces 182 that are formed on the step chain links 32 (see Figure 10). Under normal operating conditions, the radial projections 164 follow the reference surfaces 182 without making contact. This results from synchronous movement of the drive sheave 50, the belt 42 and the step chain 30. When there is relative movement between the drive pulley 50 and the step chain links 32, the cooperation between the reference surfaces 182 and the radial projections 164 causes the relative movement between the drive pulley 50 and the sensor member 160. In one example, the teeth 34 on the step chain links 32 are

formed during a casting process while the reference surfaces 182 are machined subsequently.

The spring 180 causes relative outward movement of the sensor member 160 further away from the drive pulley 50 as the bolt 172 moves into an end 178 of the slot 176. Such movement preferably actives the brake device 60. An appropriate linkage arrangement (not illustrated) activates the release mechanism 82 such that the brake device 60 becomes activated at the time that there is relative movement between the step chain links 32 and the drive pulley 50. The described action of the sensor member 50 provides an indication of some failure in the drive connection between the drive belt 42, sheave 50 and the step chain links 32.

Referring now to Figures 11A and 11B, the example release mechanism 82 is shown in two operating conditions. Figure 1lA shows the release mechanism 82 in a position where the engaging member 72 is held back so that the brake does not apply a braking force to the chain 30. The illustration of Figure 10B shows an activated position where the engaging member 72 urges the belt 62 into engagement with the step chain 30.

In this example, the release mechanism 82 includes a ball and cage device 260. A shaft 262 is connected with the support bracket 74 near one end 264 of the shaft. An opposite end of the shaft 262 has an enlarged portion 266. A circumferential groove 268 is provided at a selected position along the enlarged portion 266. A ball 270 is at least partially received within the groove 268 as shown in Figure 1 lA. Only one ball is shown but a plurality preferably are used. An inner sleeve portion 272 includes a plurality of holes that at least partially receive the ball 270. The inner sleeve 272 is secured at one end to the engaging member 72. An outer sleeve 280 has an interior surface with a first nominal dimension at 182 and an enlarged inner dimension at 284.

The outer sleeve 280 remains in the position illustrated in Figure 11A when the brake 60 should not be applied. When the release mechanism 82 responds to movement of a linkage or cable associated with a belt sensor, for example, the outer sleeve 280 is urged upward (according to the drawings) such that the larger inner portion 284 moves into a longitudinal position where the ball 270 can move outward and exit the groove 268. In this condition, the inner sleeve 272 is free to move axially

relative to the shaft 262. Accordingly, in this condition nothing withstands the urging force of the biasing members 80 that cause the engaging member 72 to move the belt 62 into engagement with the step chain 30.

The example arrangements of a releasing mechanism 82 provides a sufficient holding force to withstand the forces of the biasing members 80 to maintain the brake device 60 in a non-activated state until needed. The illustrated example also allows for activation of the brake device responsive to a relatively small activation force (i. e., a pulling force from a linkage or cable associated with a belt sensor). In some situations, a purely mechanical sensing, activating and release arrangement are preferred to avoid undesirable auxiliary brake activation during a power shortage, for example.

The inventive arrangement provides an auxiliary brake device that is useful for escalator systems that have non-traditional drive modules. The inventive arrangement is not so-limited, however. Further, the preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the scope of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.