| CLAIMS 1. A method to minimize loads of arrest in a trolley, the method comprising: providing a trolley traveling along a cable suspended from supports proximate first and second ends of the cable; initiating, proximate the first end of the cable, relative motion of the trolley with respect to the cable in response to a gravitational force; applying a braking force between the trolley and the cable to control the speed of the trolley along the cable; approaching, by the trolley, the second end of the cable; relieving, proximate the second end of the cable, the braking force during a continuation of the motion of the trolley with respect to the cable; and transferring a first portion of kinetic energy corresponding to the trolley into a deflecting element deflecting along the direction of the cable. 2. The method of claim 1 , wherein the trolley further comprises a frame, a sheave mount pivotably connected to the frame, and a sheave, rotatably mounted to the sheave mount to roll along the cable, the sheave and sheave mount suspending the frame below the cable. 3. The method of claim 2, wherein applying the braking force comprises pivoting the frame with respect to the cable in a first direction. 4. The method of claim 3 , wherein relieving the braking force comprises pivoting the frame in a second direction, opposite the first direction. 5. The method of claim 4, further comprising transferring a second portion of the kinetic energy corresponding to the trolley into lifting the frame and a rider suspended therefrom. 6. The method of claim 5, wherein the deflecting element comprises at least one spring and an engagement member interfacing between the frame and the at least one spring. 7. The method of claim 6, wherein the engagement member comprises a capture element pivotably suspended therefrom. 8. The method of claim 7, wherein the frame comprises a guide portion extending away from the remaining portion of the frame and guiding the frame into an engagement with the capture element. 9. The method of claim 8, wherein relieving further comprises lifting of the guide by the capture element along a path reflecting the pivoting of the capture element. 10. The method of claim 9, wherein the guide further comprises a yoke having a vertex and extensions forming an opening therebetween, the opening receiving the capture element and the extensions guiding the capture element toward the vertex. 11. The method of claim 1, wherein applying the braking force comprises pivoting the frame with respect to the cable in a first direction. 12. The method of claim 1, wherein relieving the braking force comprises pivoting the frame in a second direction, opposite the first direction. 13. The method of claim 1 , further comprising transferring a second portion of the kinetic energy corresponding to the trolley into lifting the frame and a rider suspended therefrom. 14. The method of claim 1 , wherein the deflecting element comprises at least one spring and an engagement member interfacing between the frame and the at least one spring. 15. The method of claim 14, wherein the engagement member comprises a capture element pivotably suspended therefrom. 16. The method of claim 15, wherein the frame comprises a guide portion extending away from the remaining portion of the frame and guiding the frame into an engagement with the capture element. 17. The method of claim 15, wherein relieving further comprises lifting of the guide by the capture element along a path reflecting the pivoting of the capture element. 18. The method of claim 15, wherein the guide further comprises a yoke having a vertex and extensions forming an opening therebetween, the opening receiving the capture element and the extensions guiding the capture element toward the vertex. 19. A method comprising: providing a trolley traveling along a cable suspended from supports proximate first and second ends of the cable; initiating, proximate the first end of the cable, relative motion of the trolley with respect to the cable in response to a gravitational force; applying a braking force between the trolley and the cable to control the speed of the trolley along the cable; approaching, by the trolley, the second end of the cable; relieving, proximate the second end of the cable, the braking force during a continuation of the motion of the trolley with respect to the cable; transferring a portion of kinetic energy corresponding to the trolley into a deflecting element deflecting along the direction of the cable; and resolving, by the deflecting element, momentum received from the trolley, in a continuously variable direction beginning at a first direction transferring substantially no momentum along the cable and ending at a second direction transferring substantially all momentum along the direction of the cable. 20. A method to decelerate a trolley, the method comprising: initiating descent of a trolley along a cable, controlling the speed of the trolley descending the cable by applying a braking force; and arresting the trolley by capturing a guide portion of the trolley by a capture element pivotably suspended from the cable, relieving the braking force by lifting the guide portion according to the pivoting of the capture element, and converting a portion of kinetic energy corresponding to the trolley into deflection of a spring. |
FIELD OF THE INVENTION
This invention relates to suspended cable systems and, more particularly, to novel systems and methods for braking and retrieving trolleys traveling on suspended cable systems.
BACKGROUND
When using a trolley as the basis for an amusement ride, revenue may largely depend on the number operators employed to operate the ride and throughputs the number of users served within a given period of time. Currently, to a large degree, safety concerns dictate the numbers for both. For example, one of the potential hazards of an amusement ride employing a trolley is the possibility of collision. A first rider may ride a first trolley to some location along a cable. Assuming that the first rider has reached the bottom and exited the ride, a second rider may ride a second trolley down the same cable. Accordingly, if the first rider did not actually reach the lower end due to over- braking, serious injury may occur when the second rider collides with the first rider. What is needed is a trolley retrieval system configured to maximize user throughput, minimize operator interaction, and reduce or eliminate the risk of collision.
BRIEF SUMMARY OF THE INVENTION
In view of the foregoing, in accordance with the invention as embodied and broadly described herein, a method and apparatus are disclosed in one embodiment of the present invention as including a trolley comprising a frame, a brake assembly, and a sheave mount.
In selected embodiments, an apparatus and method in accordance with the present invention may minimize force loads and distribute impulse loads of arrest in a trolley. In certain embodiments, this method may begin with providing a trolley traveling along a suspended cable. The trolley may be freed to travel down the cable under the impetus of a gravitational force. A braking force may be applied between the trolley and the cable to control the speed of the trolley as it travels along the cable.
When it becomes necessary to stop the trolley (e.g., at the end of the cable), the braking force may be relieved or reduced. In selected embodiments, a portion of the kinetic energy corresponding to the trolley may be used to lift the frame of the trolley and a rider suspended therefrom. This may result in a pivoting of the frame and the desired reducing of the braking force generated by the trolley. Additionally, at least a portion of the kinetic energy corresponding to the trolley may be transferred into a deflecting element deflecting along the direction of the cable. In such an embodiment, the slowing of the trolley may take on the characteristics of the deflecting element, rather than the characteristics of the trolley's on-board brake.
BRIEF DESCRIPTION OF THE DRAWINGS The foregoing features of the present invention will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only typical embodiments of the invention and are, therefore, not to be considered limiting of its scope, the invention will be described with additional specificity and detail through use of the accompanying drawings in which:
Figure 1 is a perspective view of one embodiment of a trolley and cable in accordance with the present invention;
Figure 2 is a perspective view of one embodiment of a sheave mount from a trolley in accordance with the present invention; Figure 3 is a perspective view of one embodiment of a frame from a trolley in accordance with the present invention;
Figure 4 is a perspective view of a brake assembly from a trolley in accordance with the present invention;
Figure 5 is a side elevation view of a trolley traveling toward an engagement mechanism in accordance with the present invention;
Figure 6 is a side elevation view of a trolley having a guide engaging a capture element pivotably suspended from a carriage of an engagement mechanism in accordance with the present invention;
Figure 7 is a side elevation view of a trolley and engagement mechanism fully engaged with one another, the capture element having lifted the trolley in accordance with the present invention; Figure 8 is a front quarter, perspective view of one embodiment of a guide in accordance with the present invention;
Figure 9 is a rear quarter, perspective view of the guide of Figure 8;
Figure 10 is a lower rear quarter perspective view of one embodiment of an engagement mechanism facing a trolley in accordance with the present invention; and
Figure 11 is an upper, front quarter, perspective of the engagement mechanism of Figure 10 as approached by the trolley.
DETAILED DESCRIPTION OF SELECTED EMBODIMENTS It will be readily understood that the components of the present invention, as generally described and illustrated in the drawings herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the system and method of the present invention, as represented in the drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of various embodiments of the invention. The illustrated embodiments of the invention will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout.
Referring to Figure 1, in discussing a trolley 10 in accordance with the present invention, it may be advantageous to establish a coordinate system 11. Accordingly, a trolley 10 may be defined in terms of a longitudinal direction 11 a, a lateral direction l ib, and a transverse direction lie, substantially orthogonal to one another.
A trolley 10 in accordance with the present invention may be configured for travel along a cable 12 in the longitudinal direction 1 Ia. In general, a trolley 10 of the present invention may be applied to a cable 12 held in suspension by two or more supports. For example, as disclosed in U.S. Patent No. 6,622,634 issued September 23, 2003 and entitled AMUSEMENT RIDE EMPLOYING A SUSPENDED TENSIONED STATIC CABLE, a cable 12 may be supported between two supports (e.g., towers, platforms). A first support may hold one end of the cable 12 at a higher elevation than a second support holds the other end of the cable 12. Accordingly, a trolley 10 secured to roll along the cable 12 may tend to travel from the first, upper support toward the second, lower support. While a suspended cable 12 may provide the basis for an amusement ride, other uses are also contemplated. For example, a suspended cable 12 may be used as part of a lift system transporting persons or goods over or up certain geologic obstacles. Suspended cables 12 are commonly used on ski lifts, gondolas, aerial trams, and the like. Similarly, suspended cables 12 have been incorporated into evacuation systems (e. g. , oil derrick evacuation systems). Whether for repair, evacuation, or as part of the system itself, such suspended cable 12 systems often require a trolley 10 in accordance with the present invention.
In selected embodiments, a frame 14 may provide the main structure of the trolley 10 or a base to which other components may secure. A frame 14 may be formed of any suitable material or combination of materials. Characteristics that may be considered when selecting the material for the frame 14 may include cost, formability, machineability, strength, rigidity, durability, corrosion resistance, density, etc. In certain embodiments, aluminum has been found to be a suitable material for a frame 14. A frame 14 may extend from a first end 16 to a second end 18. In certain embodiments, a brake assembly 20 may connect to the frame 14 proximate the first end 16 thereof. Proximate the second end 18, a bumper assembly 22 may connect to the frame 14. In one embodiment, a bumper assembly 22 may include a bumper 24 held between two cheek plates 26. Li selected embodiments, a bumper 24 may be formed of a friction-reducing polymeric material (e.g., HDPE, UHMWPE, PTFE). In other embodiments, a bumper 24 may be formed of an elastomeric (e.g. rubber compound) material.
A sheave mount 28 may connect to the frame 14 at a location between the brake assembly 20 and the second end 18. A sheave mount 28 may support one or more sheaves 30 positioned to roll along the cable 12. In selected embodiments, the portion
32 of the frame 14 between the sheave mount 28 and the second end 18 may be characterized as the user-suspension-portion 32. That is, the weight of a user may be directed to, and supported by, this portion 32 of the frame 14.
In certain embodiments, the frame 14 of a trolley 10 in accordance with the present invention may be suspended below a cable 12 in the transverse direction 1 Ic. A sheave mount 28 may extend upwardly from the frame 14, positioning a sheave 30 to roll on an upper surface of the cable 12. A brake assembly 20 may extend upwardly from the frame 12 to contact a lower surface of the cable 12. With the brake assembly 20 and user-suspension portion 32 on opposite sides of the sheave mount 28, the weight 34 of a user applied to the user-suspension portion 32 may generate a torque 36 or moment 36 urging the brake assembly 20 to "pitch" against the underside of the cable 12 (i.e., generate or urge rotation about an axis extending in the lateral direction lib). The greater the moment 36 generated, the greater the braking force or friction force produced by the brake assembly 20.
A carriage 38 may provide the primary interface between a user and a trolley 10 in accordance with the present invention. That is, while other locations, apertures, connection, structures, and the like may be used for redundant, fail-safe systems, in normal use, the majority of user weight 34 may be applied to the carriage 38. The carriage 38, in turn, may communicate that load to the frame 14.
The position of the carriage 38 with respect to the frame 14 may be adjusted to provided a desired braking force. For example, the greater the distance 40 between the sheave mount 28 and the carriage 38, the greater the moment 36 and resulting braking force. The opposite may also be true. That is, the braking force may be minimized by minimizing the moment arm 40 over which the weight 34 of a user may act.
Adjustability and securement between a carriage 38 and a frame 14 may be provided by any suitable structures. In selected embodiments, an array of apertures 42 may provide an array of positions at which a carriage 38 may be secured to a frame 14. A pin 44 or bolt 44 may pass through a carriage 38 and a selected aperture of the array 42 to lock the carriage 38 at a desired moment arm 40. Accordingly, a trolley 10 in accordance with the present invention may be tuned to a particular cable 12 arrangement. That is, a trolley 10 may be formed according to a single design, yet be flexible within that design to provide braking appropriate for a wide range of cable 12 arrangements.
For example, given a first cable 12 arrangement involving a comparatively larger change in elevation, a trolley 10 traveling on such a cable 12 may tend to reach excessive speeds. Thus, the carriage 38 may be secured to the frame 14 at an aperture 46 in the array of apertures 40 providing a corresponding, comparatively larger moment arm 40.
This greater moment arm 40 may increase the braking force and keep the trolley 10 within acceptable speed ranges.
Conversely, consider a second cable 12 arrangement involving a minimal change in elevation. For such an arrangement, a carriage 38 secured at certain apertures (e.g., aperture 46) may provided excessive braking. For example, the resultant braking may cause the trolley 10 to stop without reaching the unloading area at the bottom of the cable
12. According, for such arrangements, a carriage 38 may be secured to the frame 14 at an aperture 48 in the array of apertures 40 providing a minimal moment arm 40. By so positioning the carriage 38, the trolley 38 may provide greater speed along the cable 12.
While the weights of different users may vary, a trolley 10 in accordance with the present invention may automatically compensate for such variations. For example, the braking force required to regulate the speed of a trolley 10 carrying a user weighing 200 lbs. may be significantly greater than the braking force required to regulate the speed of a trolley 10 carrying a user weighing 100 lbs. However, with a single setting of the carriage 38 (i.e., a single moment arm 40), at trolley 10 may appropriately regulate the speed of both users .
The braking force generated by a trolley 10 is equal to the coefficient of friction between the brake assembly 20 and the cable 12 multiplied by the normal force urging the braking assembly 20 against the cable 12. For a single moment arm 40, the only variable becomes the weight 34 of the user. Accordingly, the normal force urging the braking assembly 20 against the cable 12, which is result of the moment 36 applied by the weight 34 of a user to the frame 14, controls the braking force. Thus, without adjusting the position of the carriage 38, the braking force generated for a user weighing 200 lbs. user will automatically be roughly twice that generated for a user weighing 100 lbs. That is, a trolley 10 may be tuned to a particular cable 12 arrangement, but need not be tuned for each user.
A trolley 10 in accordance with the present invention may include any desirable redundant or fail-safe systems. For example, in selected embodiments, a frame 14 may include a slot 50 within or along which the carriage 38 may travel. Accordingly, if the pin 44 holding the carriage 38 in a particular location were to fail, the carriage 38 would not be free to separate from the frame 14. Additionally, the orientation of the slot 50 with respect to the weight 34 of a user may urge an unpinned carriage 38 toward the end of the slot 50 corresponding to the second end 18 of the frame 14. At such a location, the moment arm 40 and corresponding braking force may be at a maximum. Accordingly, if a pin 44 were to fail, the link between the user and the cable 12 would not be lost and the trolley 10 would quickly be brought to a halt. Referring to Figure 2, in selected embodiments, a sheave mount 28 in accordance with the present invention may be pivotably secured to a frame 14. For example, in certain embodiments, a bolt 52 may extend through the frame 14. If desired, a collar 54 may be positioned over the bolt 52 to improve wear resistance, increase the rigidity of the bolt 52, or the like. In certain embodiments, to increase safety, a sheave mount 28 may provide an enclosure capturing a cable 12 therewithin. That is, once the sheave mount 28 has received a cable 12 therewithin, it may resist inadvertent removal of that cable 12. For example, in one embodiment, a sheave mount 28 may include a first side 56 extending from the bolt 52 to an aperture 58 for supporting a sheave 30. This first side 56 may include one or more ribs 60 to increase the rigidity and strength thereof. A top 62 of the sheave mount 28 may connect the first side 56 to a second side 64 of the sheave mount 28. In selected embodiments, the second side 64 may control admittance and release of a cable 12 from within the sheave mount 28. hi selected embodiments, the second side 64 of a sheave mount 28 may be separated into a hook portion 66 and a bail assembly 68. In one embodiment, the hook portion 66 may be connected to the top 62 and include an aperture 70 that, in combination with another aperture 58, may pivotably connect a sheave 30 to the sheave mount 28. A hook portion 66 may also include a hook 72.
A bail assembly 68 may include a bail 74 and a bail mount 76. A bail mount 76 may connect to the bolt 52 or collar 54 extending through the frame 14 from the first side
56 of the sheave mount 28. A bail 74 may, in turn, extend from the bail mount 76 to engage the hook 72 of the hook portion 66. In selected embodiments, a bail 74 may be biased toward a closed position with respect to the hook 72. Accordingly, in certain embodiments, a bail 74 may be moved {e.g., pivoted) to permit entry of a cable 12 into the sheave mount 28. Once the cable 12 is captured with the sheave mount 28, the bail
74 may be released to return automatically to its preferred (biased), closed position. In selected embodiments, the interface between a bail 74 and a hook 72 may be such that the bail 74 is configured to open only toward the interior of the sheave mount
28. Thus, the bail 74 may be biased to permit entry of a cable 12 into the sheave mount
28 but resist inadvertent removal of that cable 12. As an additional safety feature, in certain embodiments, a bail mount 76 may include a slotted aperture 78 extending therethrough to receive the bolt 52, collar 54, or some combination thereof. A tensioner
80 may control the position of the bolt 52, collar 54, etc. within the slotted aperture 78.
Accordingly, once a cable 12 has been received within a sheave mount 28 and the bail 74 has returned to a closed position, the tensioner 80 may be adjusted to move the bail assembly 68 with respect to the bolt 52, collar 54, etc. Thus, the bail 74 may be pulled 82 firmly into engagement with the hook 72. In such an arrangement, the hook 72 may resist opening of the bail 74. Additionally, the bail assembly 68 may assist in transferring loads from a sheave 30 to the frame 14 of the trolley 10. That is, the first side 56 of the sheave mount 28 need not act alone, thereby increasing the load-bearing capacity, and corresponding safety factor, associated with the sheave mount 28.
Referring to Figure 3, in selected embodiments, a trolley 10 in accordance with the present invention may include a brake assembly 20 that is pivotably secured to the frame 14. A pivotable connection between a brake assembly 20 and a frame 14 may support a more controlled and even wear on the break assembly 20. In certain embodiments, to provide a pivoting securement between a brake assembly 20 and a frame 14, the frame 14 may include various apertures 84, 86. A pivot aperture 84 may be sized and shaped to receive a pivot bolt (i.e., a bolt about which the brake assembly 20 may pivot). A limiting aperture 86 may be sized and shaped to receive a limiting bolt (i. e. , a bolt moving with the brake assembly 20 and abutting the extremes of the limiting aperture 86 when the brake assembly 20 reaches a desired limit to its pivoting).
In selected embodiments, a frame 14 may include multiple pivoting apertures 84a, 84b, 84c. For example, a first pivoting aperture 84a may provide a pivot point (e.g., central pivot point) for a brake assembly 20 of a first size. A second pivoting aperture 84b may provide a pivot point for a brake assembly 20 of a second, smaller size. A third pivoting aperture 84c may provide a pivot point for a brake assembly 20 of a third, even smaller size. If desired, multiple limiting apertures 86 may be provided. In one embodiment, however, a single limiting aperture 86 may be sized and shaped to providing a limiting effect to brake assemblies 20 pivoting in any of the various pivoting apertures 84. Referring now to Figures 1 and 4, a brake assembly 20 in accordance with the present invention may provide significant adjustability. For example, a brake assembly 20 may include a brake pad 88 that may be removed and replaced, as wear so dictates. Additionally, a brake pad 88 may itself be adjustable to provide a desired or customized braking effect. If desired or necessary, a brake assembly 20 may include various structural members providing additional strength, rigidity, safety, or the like. For example, in selected embodiments, a brake assembly 20 may include one or more cheek plates 96. hi selected embodiments, a brake assembly 20 may include a groove 104 or slot
104 sized and positioned to accommodate a portion of the frame 14 therewithin. Accordingly, in such embodiments, a brake assembly 20 may effectively straddle the frame 14, permitting various fasteners (e.g., pivot bolts, limiting bolts, etc.) to pass through both the brake assembly 20 and the frame 14. If desired or necessary, a slot 104 may extend some distance less than the entire length of the brake assembly 20. For example, in one embodiment, opposing brake shoes 90a, 90b may each include a shoulder extending to meet the other. The shoulders may effectively close the slot 104.
Accordingly, any fastener (e.g., assembly bolt) passing through the shoulder may be tightened without clamping the frame 14 and reducing the ability of the brake assembly 20 to pivot with respect to the frame 14.
A brake assembly 20 in accordance with the present invention may include a capture 108. A capture 108 may secure a cable 12 therewithin. That is, once atrolley 10 is applied to a cable 12, the capture 108 may secure the brake assembly 20 to the cable 12. Accordingly, the capture 108 may provide a redundant safety mechanism and, should there be a catastrophic failure of the sheave mount 28, the trolley 10 may be secured to the cable 12 via the brake assembly 20 and capture 108. If desired, a capture 108 may include a slide 110. In certain embodiments, a slide
110 may provide an interface between a capture 108 and a cable 12. For example, a capture 108 may in certain situations slide along a cable 12. In such situations, a slide 110 may prevent abrasion or grinding that may reduce the structural integrity of the capture 108. In one embodiment, a slide 110 may include a groove 112 or slot 112 providing a preferred or default location of engagement between a slide 110 and a cable 12, should contact occur therebetween.
Referring to Figures 5-7, in selected embodiments, a bumper assembly 22 in accordance with the present invention may be configured as a guide 22. For example, a bumper assembly 22 may be formed as a guide 22 or yoke 22 having two extensions 256, 258 angling away from one another to form a central vertex 260 therebetween. A guide 22 may facilitate engagement with an engagement mechanism 262.
In selected embodiments, an engagement mechanism 262 may be configured to slide along a cable 12. An engagement mechanism 262 may provide the interface between a trolley 10 and a deflecting element. Momentum may be transferred from a moving trolley 10, through an engagement mechanism 262, and into a deflecting element, where it may be cushioned, absorbed, dispersed, or otherwise managed. Accordingly, the deflecting element (not shown) may gradually bring a trolley 10 to a stop.
In certain embodiments, a deflecting element may comprise the terminal brake 50 disclosed in U.S. Patent No. 6,622,634 incorporated herein by reference. In other embodiments, a deflecting element may comprise the terminal brake (item 50) disclosed in U.S. Patent No. 6,622,634, less the weights (item 60 therein). In still other embodiments, a deflecting element may comprise the terminal brake disclosed in U.S. Patent No.6,622,634, with the weights 60 replaced by light weight interfaces aligning the various springs 58 with respect to one another and the cable 14.
In certain embodiments, an engagement mechanism 262 may include a carriage 264 and a capture element 266. In one embodiment, a capture element 266 may be formed as a ring pivotably suspended from a carriage 264. A capture element 266 may be positioned to capture or engage the guide 22 of an approaching trolley 10. In selected embodiments, the extensions 256, 258 of a guide 22 may direct the capture element 266 toward the vertex 260 thereof. Additional movement 268 of a trolley 10 toward an engagement mechanism 262 may result in the capture element 266 pivoting with respect to the carriage 264. In selected embodiments, a capture element 266 may pivot with respect to a carriage 264 about a single point. Accordingly, a capture element 266 may pivot in an arc. Due the engagement between a guide 22 and a capture element 266, this pivoting may result in a lifting 270 of one end 16 of a trolley 10. This lifting 270 may continue until a guide 22 or a portion thereof contacts the engagement mechanism 262.
One effect of this lifting 270 may be a reduction in the normal force between a brake assembly 20 and a cable 14, resulting in a reduction in the braking force produced by the brake assembly 20. That is, the lifting 270 may pivot a frame 14 of a trolley 10 in a direction opposite to the direction 36 urged by the weight 34 of a user. In certain embodiments, a guide 22 may include a top bumper 272 extending upward therefrom. A top bumper 272 may be positioned to contact an underside of an engagement mechanism 262. Such contact may define an upper limit for the lifting 270. Upon reaching this upper limit, no further pivoting is possible and momentum associated with a trolley 10 may be directed through the engagement mechanism 262 and into a deflecting element in accordance with the present invention. Accordingly, a trolley 10 and engagement mechanism 262 may travel 274 together down the cable 12 against a resisting force (e.g., a gradually increasing resistance force, such as that of a spring) produced by a deflection element.
Because the mass of a capture element 266 may be small, only a relatively small impulse will be produced by a trolley 10 impacting thereagainst. Additionally, because the capture element 266 may pivot with respect to the carriage 264, the mass of the carriage 264 may not factor significantly into the initial impulse. Accordingly, initially substantially no momentum may be resolved by the deflecting element. However, as the capture element 266 pivots toward its upper limit, gradually more and more of the momentum of the trolley 10 and rider may be communicated through the capture element
266 to the carriage 264. Upon reaching the upper limit, the remaining momentum associated with a trolley 10 may be directed through the engagement mechanism 262 and into a deflecting element. Because an impulse is equal to force (mass multiplied by acceleration) multiplied by the time interval over which the force acts, this significant decrease in acceleration reduces the forces generated by the mass being stopped.
Referring to Figures 8 and 9, in selected embodiments, a guide 22 may be formed with two cheek plates 26 securing and stabilizing a bumper 24 held therebetween. The bumper 24 may extend beyond the cheek plates 26 such that the bumper 24 contacts a capture element 266 while the cheek plates 26 do not. Selected fasteners 276 may secure the bumper 24 and cheek plates 26 together. Other fasteners 278, spacers 280, shims 282, and the like may support securement of a guide 22 to the frame 14 of a trolley 10.
In certain embodiments, a bumper 24 may extend upward to form the top bumper 272. Alternatively, as shown in the illustrated embodiment, a top bumper 272 may be formed as a separate unit. For example, a top bumper 272 may include a bumper material 284 (e.g. , HDPE, UHMWPE, PTFE, rubber compound, or the like) and a bumper mount 286 secured to a guide 22 by a fastener 288. In selected embodiments, apertures 290, 292 may formed in the bumper material 284, bumper mount 286, and guide 22 as necessary to effect securement of the top bumper 272 in place.
Referring to Figures 9 and 10, in selected embodiments, a carriage 264 in accordance with the present invention may include one or more cable interfaces 294 secured by fasteners 296 to a frame 298. Cable interfaces 294 may be formed of friction reducing or friction resistant materials (e.g., HDPE, UHMWPE, PTFE, or the like). In one embodiment, a carriage 264 may include three cable interfaces 294, namely an upper cable interface 294a, a first lower cable interface 294b, and a second lower cable interface 294c. In certain embodiments, apertures 300 may be formed at the seams between selected cable interfaces 294 to permit a cable 12 to pass through a carriage. By positioning the apertures 300 at the seams, a carriage 264 may be installed after a cable 12 is already in place.
The frame 298 of a carriage 264 may include a mount 302 providing a location for a capture element 266 to secure to the frame 298. In selected embodiments, a fastener 304 may pivotably connect a capture element 266 to a mount 302. A capture element 266 in accordance with the present invention may have any suitable shape or configuration. In selected embodiments, a capture element 266 may be formed as a ring.
An engagement mechanism 262 in accordance with the present invention may be formed of any suitable materials. Materials may be selected to provide desirable strength, wear resistance, and the like. In selected embodiments, the materials and the shapes of an engagement mechanism 262 may be selected to reduce or minimize the mass thereof. By reducing the mass, the forces required to accelerate the engagement mechanism may be reduced. Accordingly, the process of arresting a trolley 10 in accordance with the present invention may be rendered smoother and more gradual.
The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative, and not restrictive. The scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
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