MX2007013361A - Energy absorber for counterbalance mechanism. - Google Patents

Abstract

An energy-absorbing device for use with a counterbalance mechanism to relatively harmlessly absorb energy potentially released should a component of the counterbalance mechanism fail. A frame is attached to a portion of the counterbalance mechanism and supports an impact receiving member, and a plurality of deformable support members. In the event of a failure in the counterbalance mechanism, a part of the counterbalance mechanism strikes a face of the impact receiving member. Deformable support members are attached to the opposing face of the impact receiving member and are deformed by the impact and thus absorb the energy that is transferred by the impact. The deformable support members and the impact receiving member are readily replaceable.

Description

ENERGY ABSORBER FOR COUNTERWEIGHT MECHANISM DESCRIPTION Background and field of the invention The present invention relates to counterweight mechanisms and in particular to a device for safely absorbing energy from > a part of a counterweight mechanism accidentally released by a failure of a part of such a counterweight mechanism. Counterweight mechanisms have been used for a long time to allow the lifting of heavy objects by providing a force in opposition to the weight of that heavy object. The force provided by the counterweight mechanism is typically slightly less than a load to be balanced so that the counterweight mechanism bears a large part of the load under static conditions. Such an arrangement allows the load to be moved easily by applying a small additional force, as compared to the force that would otherwise be required to move the load without the counterweight mechanism. Counterweight mechanisms have been widely used in many mechanical devices, including lifting bridges and the like. One such application is in a rail freight car that has several covers that are capable of carrying cargo. U.S. Patent Nos. 5,743,192; 5,794,537 and 5,979,335 disclose a rail freight car of several units to carry automobiles carrying several levels of decks. In each of the disclosed loading carts, a plurality of automobiles can be supported on the covers that are adjustable in height. Each end portion of the mid-level cover in each unit of the load carriages is mounted on a pivot shaft at its inner end so that the outer end portion of the cover, located at the end of the cover, can be raised and lowered. the car unit to facilitate the unloading of vehicles at the lowest level of the car. In U.S. Patent No. 7,055,441, the disclosure of which is incorporated by reference, a counterweight mechanism allows a pivoted end portion of the mid-level deck of such rail loading cart to be lifted and lowered. easily by your operator. The counterweight mechanism has a tensioned elongated member, coupled to the hinged end portion of the cover, which applies a lifting force from a spring to allow a person lift the hinged end portion of the cover with just hand pressure. The lifting force provided by the counterweight mechanism assists the operator in lifting the hinged end portion of the deck by carrying much of its weight as it moves between its raised and lower positions. Such a counterbalancing mechanism involves the risk that the failure of a cable carrying the tension could release a large power spring or a large counterweight, causing damage to the counterweight mechanism and potentially causing injury to an operator. In the event of a failure of the tension-bearing member, the counterweight mechanism can release an amount of energy related to the force that supported the counterweighted object, and a part of the counterweight mechanism can be released potentially causing structural damage and bodily injury . The counterweight mechanism for roofs within a rail freight car may be supporting more than a ton of weight and the energy released if a fault occurs is potentially large. The energy that is potentially released as a result of a failure in the counterweight mechanism, thus presents a risk of damage to the rest of a counterweight mechanism and to the associated structure of the load carriage and a risk of injury to nearby personnel.

What is needed then is an energy absorbing mechanism capable of absorbing a large part of the energy that can be released in the event of a failure in a counterweight mechanism in a rail freight car, so that the failure of the Counterweight mechanism does not result in structural damage to the rail car or injury to nearby personnel.

SUMMARY OF THE INVENTION The mechanism described here meets the aforementioned needs by providing an energy absorption device as defined by the appended claims. In one embodiment such a device can be associated with a counterweight mechanism, to protect a rail car and a nearby personnel against injury in the event of a failure of the counterweight mechanism. In one embodiment the disclosed device includes a deformable support member that is left in response to an impact resulting from a failure of a load bearing portion of a counterweight mechanism. The energy absorbing device is attached to a housing for a force generating element of the counterweight mechanism, such as a spring or a counterweight and prevents a force generating element from suddenly being released and a force transmitting member damaging the structure of the load carriage, dampening an impact and absorbing a significant portion of the energy of the force generating element. One embodiment of the energy absorbing device is associated with a counterweight mechanism that supports a movable hinged end portion of a cover of a rail loading cart. In one embodiment of the disclosed apparatus, the energy absorbing device includes a blocking member or impact receiver mounted on a plurality of deformable support members. The impact receiving member is connected to a frame attached to one end of a housing for a movable part of the counterweight mechanism. In the event of a failure, a released part of the counterweight mechanism that moves toward the locking member or the impact receiving member strikes the member on a face that faces into the interior of the housing. As a result of such an impact, the deformable support members are bent from their original configurations and thereby absorb the kinetic energy of the released part. In one embodiment, the energy absorbing device is attached to a housing for a mobile portion of a counterweight mechanism and includes clamping bars that extend away from one end of the housing. The deformable support members may have a "U" shape and may be located where they are brought to bend in response to the collision of thrown parts of a counterweight mechanism against an impact receiving member so as to absorb the energy of the parts. mobiles thrown by the failure of a part of the counterweight mechanism. In one embodiment one end of each deformable and U-shaped support member is attached to one side of the impact receiving member opposite to a face to which the moving force generating element would collide if released as by a failure of cable. The other end of each of the deformable and U-shaped support members can be connected to the fastening bars by means of a removable fastener such as a combination of nut and screw. This structure allows the deformed portion of the energy absorbing device to be replaced after an impact occurs by simply separating the deformable support members from the support bars. In one embodiment of the energy absorbing device the blocking member or the impact receiving member may be a plate in the form of an annular ring which defines a central opening through which an accessory attached to one end of the counterweight mechanism can fit. In one embodiment of the energy absorbing device, the clamping bars are chamfered to provide additional space in which the deformable support members can be deformed to absorb additional energy from a moving member of a counterweight mechanism. The foregoing and other objects, features and advantages of the invention will be more readily understood upon reading the following detailed description of the invention, taken in conjunction with the accompanying drawings.

Brief description of the figures Fig. 1 is a cutaway side elevational view of a portion of a unit of a multi-unit rail freight car, showing a movable end portion of a car loading deck located in an inclined upward position. Fig. 2 is a view of the interior detail, on an enlarged scale, showing the uppermost portion of a side wall of the body of the unit of a trolley rail load shown in fig. 1, which shows one end of a cover in an elevated position and also shows a counterweight mechanism equipped with an energy absorption mechanism. Fig. 3 is an isometric lower view, on an enlarged scale, of the energy absorption mechanism shown in FIG. 2, the lower portion of a portion of the guide tube of the counterweight mechanism is also shown. Fig. 4 is an exploded isometric bottom view of the energy absorption mechanism shown in FIG. 3. Fig. 5 is a sectional view, taken along line 5-5 of FIG. 3, which shows a portion of the counterweight apparatus in a slightly loaded condition within the guide tube. Fig. 6 is a sectional view, taken along line 5-5 of FIG. 3, which shows a portion of the counterweight apparatus after having struck the energy absorbing device and also shows the deformable support members in a deformed state. Fig. 7A is a sectional view of the combination of one of the deformable support members and an alternative embodiment of a fastening bar.

Fig. 7B is a sectional view of the support member and the holding bar, shown in FIG. 7A, showing the deformable support member in a deformed condition.

Detailed description of the modalities With reference to the figures forming part of the description, fig. 1 shows part of a carriage body 10 of a carriage unit of a multi-unit rail freight car incorporating one embodiment of the present invention. The load carriage may include two or more adjacent carriage units, and each respective carriage unit may include a load box 12, a middle cover 14 and an upper cover 16, for selectively supporting and storing the automobiles 18 in an arrangement of three levels. Each tire preferably has a shape that provides ample strength to support automobiles 18, while providing sufficient space to accommodate automobiles 18 of various heights that the car is desired to transport. As seen in fig. 1, the cars 18 stored in the lowest level of the load carriage body 10 rest in the respective load box 12 of each carriage unit. To maximize the use of space vertical available at the two upper load levels, the middle cover 14 is placed where it would prevent the loading and unloading of the automobiles 18 from the cargo box 12 out this one not for a hinged end portion 20 of the middle cover 14 that it can be selectively lifted while the cars 18 are loaded into or unloaded from the loading box 12. It should be understood that each of the carriage units may have an average cover 14 and an upper cover 16, and that the middle cover 14 in each carriage unit may include a hinged end portion 20 at either or both ends. A respective counterbalance apparatus 22 is provided on each side of the carriage unit to carry part of the weight of the hinged end portion 20 so that it can be easily lifted when necessary. The counterweight apparatus includes a power absorption device 24 for absorbing the energy that can be released if a failure of the counterweight apparatus 22 occurs and it results that a piece of the counterweight apparatus 22 stops moving. The energy absorbing device 24 prevents an impact of such a piece released from the counterweight apparatus from causing substantial damage to the counterweight apparatus 22, an associated cover, or the associated support structure of the load carriage body 10. In addition, a portion of the energy absorbing device 24 can be replaced after an impact and can thus reduce the costs for repairs if a failure of the counterweight device 22 occurs. Each counterweight device 22 may include a force transmitting member, such as a cable 28 or chain (not shown) that interconnects and transmits forces between a counterweighted object such as the hinged end portion 20 and a force generating element, such as a spring 32 or a counterweight (not shown). The force generation elements of the counterweight mechanisms 22 as a whole can generate a lifting force that is slightly less than the applied portion of the weight of the hinged end portion 20. Each force transmitting member may include a first elongated tension carrier segment 34 operably connected to and extending upwardly from the hinged end portion 20 and a second elongated tension carrier segment 36 operatively interconnected with the generator element force so that the voltage in the first elongated voltage carrier segment 34 is caused by the voltage in the second elongated voltage carrier segment 36, which in turn is caused by the force generation element. In a simple counterweight mechanism, the force transmitting member may be a cable 28 and the element Force generator may include spring 32. In this example, it may be appropriate to include a direction change force transfer device 42, which includes one or more splined pulleys 44, or other mechanisms such as rocker arms (not shown). The direction change force transfer devices 42 can be positioned between the first elongated tension carrier segment 34 and the second elongated tension carrier segment 36. In a more complex counterweight mechanism, an appropriate force transmitter arrangement could include gears, rigid members, rockers, etc. The middle cover 14 can be provided in the form of three segments arranged end to end, with the center segment securely and firmly fastened to the side posts 40 by screws or other releasable but secure fasteners to incorporate the structural mid deck 14 inside. and adding stiffness to the entire carriage unit as well as being solidly supported by the side walls 46. The hinges 47 rotatably connect the hinge-end portion 20 with hinges to two horizontal support beams 48 extending longitudinally as shown in FIG. length of the opposite side walls 46 of the carriage body 10 at equal heights and which are rigidly fastened to the side walls 46 by medium of fasteners such as screws. Each of the horizontal support beams 48 extends towards the interior of the side walls 46, so that when the hinged end portion 20 is in a down position it is supported along its lateral margins by means of the 48 horizontal support beams. In this way, the horizontal support beams 48 support the weight portion of the hinged end portion 20 and any automobiles 18 or other load carried on the hinged end portion 20 greater than the weight supported by the counterweight apparatus 22. Each of the horizontal support beams 48 is positioned at a vertical height along its respective side wall 46 where the hinged end portion 20 abuts the fixed portion of the middle cover 14 on a pivot axis defined by the hinges 47 through which the inner end of the hinged end portion 20 is joined. The hinges may allow an outer end 50 of the hinged end portion 20 of the middle cover 14 to be raised as much as about 1.22 m (4 feet) to an inclined position above the horizontal support beams 48. The elevation of the hinged end portion 20 of the middle cover 14 at the time of emptying allows the cars 18 to be moved on the trailers 52 and the body cross members 54 of the body 10 of carriage and in or out of the loading box 12 during loading and unloading of the loading carriage 2. With reference to FIG. 2, the counterweight device 22 is used to support most of the weight of the hinged end portion 20 to facilitate lifting and lowering manually. The counterweight device 22 applies a lifting force from the force generating element to the outer end 50 of the hinged end portion 20 through a tension carrying member, which may be, for example, a flexible steel wire 28. 0.794 cm (5/16") in diameter The cable 28 operatively connects the hinged end portion 20 to the force generating element and extends up and around the grooved pulleys 44 that can be mounted at fixed locations, such as between the corner post and the side post 40 which is adjacent the corner post 38 along the side wall 46 in the direction towards the median length of the car body 10. With reference again to Fig. 2 , the generally helical compression spring 32 or other force generating element can be held in a protective cover such as a guide tube 56, securely mounted on the carriage body 10, where the compression spring 32 is free to spread and compress, or a counterweight is free to move up or down. The spring 32 and the guide tube 56 can also be located in an interior space between the corner post 38 and the adjacent side post 40. In this way, the counterweight device 22 is located in what would otherwise be a unused space within the rail car body 10 and does not interfere with any other structure or load inside the car. The guide tube 56 comprises an inner liner handle 58, and an upper end 60 which is securely connected to the guide tube 56 retains the upper end of the spring 32 and opposes the force of the cable 28 to compress the spring 32 and thus provide a force that supports part of the weight of the movable cover part 20. The handle 58 can be made of, or coated with, at least one layer of polymeric resin such as UHMW polyethylene so as to minimize friction and wear when the compression spring 32 moves within the guide tube 56. The connection upper 60 defines an opening 62. The cable 28 extends through the opening 62 and through the compression spring 32, and is secured to a cable end connection 64, such as by placement around a special screw of the connection 64 and is held by a cable clamp 66 crimped or crimped.

The cable end connection 64 is connected to the end of the spring 32 as by engagement with a convenient spring fastener 68. The spring fastener 68 can, as shown, be in the shape of a cup with a suitably robust annular bottom plate 70 and an upwardly extending flank 72 surrounding a lower end of the spring 32, so that the fastener 68 acts as a piston that supports the lower end of the spring 32 and guides the spring 32 as it moves within the guide tube 56. The end connection 64 can have a portion projecting upward and coincidently coincides with the central opening 74 in the lower plate 70 and a radial flange 76, extending below the lower plate 70, which is too large to pass through the opening 74. The handle 58 facilitates the movement of the fastener 68 within the guide tube 56. Due to the arrangement of the cable 28, the movement of the end portion 20 hinged upwardly or downwardly causes the fastener 68 to slide oppositely within the handle 56. The movement of the fastener 68, at its ez, compresses the compression spring 32 or allows it to expand downwardly under the upper connection 60, depending on the direction in which the fastener 68 is moved.

The length of the cable 28 and the force of the compressed spring 32 can be such that when the hinged end portion 20 is in the down position the compression spring 32 applies a lifting force to the hinged end portion 20 which is slightly less than that which would lift the outer end 50 of the hinged end portion 20. It will be understood that the compression spring 32 should be long relative to the distance through which a point on the cable 28 will travel when the hinged end portion 20 of the middle cover 14 is raised or lowered, so that the magnitude of the lifting force provided by the counterbalance apparatus 22 within a small range during lifting and abatement of the hinged end portion 20 remains. The hinged end portion 20 of the middle cover 14 can thus easily be lifted during the loading of the automobiles 18 in the loading box 12 to provide the overhead clearance above the rocker 54 as the cars pass over the wheeled trailer 52 at each end of the multi-unit freight car or on a trailer shared between car units. Figs. 2-6 show the energy absorption device 24 that is used to absorb the energy coming from a spring 32 or other element force generator released by a fault in the counterweight apparatus 22 such as a cable failure 28. Such released spring 32 would result in an impact of the fastener 68 against the energy absorbing device 24. Should the cable 28 fail, the spring 32 would rapidly expand from a compressed condition between the upper connection 60 and the fastener 68, releasing the spring fastener 68, the end connection 64, and any attached portion of the cable 28 downward to through the guide tube 56 to the energy absorption device 24. The energy absorbing device 24 helps to prevent substantial damage to the guide tube 56 and helps prevent an injury from occurring to an operator who may be manually lifting the hinged end portion 20 of the middle cover 14. The device 24 of energy absorption can be constructed as shown, to include energy absorbing parts that are easily replaced after an impact occurs. The construction of the energy absorbing device 24 also allows easy access to the interior of the guide tube 56 to be able to repair the spring 32 or the cable 28. Referring now to FIGS. 3 and 4, as depicted, the energy absorbing device 24 is attached to the lower end of the guide tube 56 and includes a base that may be in the form of a collar 82, which can be welding to the guide tube 56, and a plurality of clamping rods 84, each securely joined by being welded to or formed as an integral part of the collar 82. In one embodiment, the collar 82 is welded or attached in some other fixed manner to guide tube 56; however, it will be understood that the collar 82 can be removable as long as it is capable of supporting the maximum anticipated amount of energy of a potential impact of a released part of a counterweight mechanism without the separation of the guide tube 56. A first end or External end, of a deformable member 86 is detachably connected to each clamping bar 84 as by means of a fastener such as a combination 88 of screw and nut. Each deformable support member 86 is a strip of metal bent in a "U" shape, with the second end 90 of the strip, which may be wider than the first end or external end, being attached to a blocking member 92 or impact receiver that fits inside or aligns with the lower end of the guide tube 56 to block or close that end of the guide tube 56 and thus safely contain the spring 32, the spring clip 68 and the end connection 64 in the case of a cable failure. The impact receiving member 92 and the guide tube 56 are formed in a similar manner, and the receiving member 92 The impact has a size slightly smaller than the inside of the guide tube 56, so that it fits inside the guide tube 56. For example, the guide tube 56 and the impact receiving member 92 can be of a cylindrical shape, in which case the diameter 93 of the impact receiving member 92 is slightly smaller than the inner diameter of the guide tube 56, and the impact receiving member 92 can fit within the interior of the guide tube 56, sufficiently loose so as not to get stuck in the collar 82 when it is hit by a part thrown from the counterweight mechanism, as shown in figs. 5 and 6. The impact receiving member 92 may be of flat plate steel in the form of an annular ring defining a central hole 94, as shown in FIG. 4. The impact receiving member 92 has an upper face or first face 96 and a lower face, second face 98. The radial distance between the central hole 94 and the outer margin is designed to provide space for securing the upper end 90 of each deformable member 86 of support. The upper ends 90 of the deformable support members 86 can be joined as by welding to the second face 98 at uniformly spaced positions around the central hole 94. A pair of mounting ears 100 are attached to the second face 98 of the member 92 Impact receiver, aligned with each other on sides opposites of the central hole 94 along an imaginary diametrical line through the annular plate 92, as shown in Figs. 3 and 4. Each mounting ear 100 is located between two deformable support members 86 in one embodiment. A stop bar 102 is attached to the ears 100, extending along the diameter of the impact receiving member 92 and between the ears 100, attached, for example, by the combination 101 of screw and nut. The stop bar 102 thus extends through the hole 94 as shown in FIG. 3, in a separate location a small distance below the lower face 98, leaving space for the cable end connection 64 to protrude through the central hole 94 when the lower plate 70 of the fastener 68 comes into contact with the member 92 of Annular impact receiving plate. The length of the stop bar 102 is slightly smaller than the inside diameter of the guide tube 56 so that the stop bar 102 fits within the guide tube 56, as shown in FIG. 3. The deformable support members 86 can be of any configuration that is capable of flexing in response to an impact against the impact receiving plate 92 and thus absorbing energy from the moving spring 32 or a counterweight of a counterweight mechanism.

As shown in figs. 3 and 4, the deformable support members 86 may be plate steel cut to a thin flat bar shape and bent to have a generally "U" shape, so that each deformable support member 86 includes a joined or upper end 90, a U-shaped central portion 104, and the removable end 106. The U-shaped central portion 104 of the deformable support member 86 extends away from the second or lower face 98 of the annular locking member 92. The removable end 106 of the deformable support member 86 extends parallel with the attached end 90 generally toward the second face 98 of the impact receiving element 92 at a location radially outwardly from the central hole in the impact receiving plate member 92. annular, but does not extend all of the distance back to the second face 98. The removable end 106 of the deformable support member 86 defines a hole 108 which is aligned with a hole 110 defined in the lower portion of the bar 84 of clamping when the annular impact receiving plate member 92 is placed inside the collar 82. The nut and screw combinations 88 releasably join the disposable and replaceable part of the energy absorbing assembly 14 to the collar 82.

Figs. 3 and 4 show that four deformable support members 86 are used, although it will be understood that any convenient number of deformable support members 86 suitable for absorbing the anticipated amount of energy of the counterweight mechanism can be used with an equal number of clamping bars. 84. The modality shown in figs. 3 and 4 have deformable support members 86 evenly spaced around the inner perimeter 100 of the annular ring 96 so that each deformable support member 86 is positioned to absorb a substantially equal amount of energy if an impact occurs. Referring again to Figures 5 and 6, the energy absorbing device 24 is attached to one end of the guide tube 56 as by welding the collar 82 to the guide tube 56 adjacent to its lower end, where the energy absorbing device can block a thrown portion such as the spring 24 and the cable 28 of a counterweight mechanism, and receive the impact of a thrown part in the event of a failure in the counterweight device 22. The force generation element fits within the fastener 68 of spring and urges the fastener 68 through the guide tube 56. The end connection 64 can be smaller than the central opening 94 in the annular impact receiving plate member 92 and fits through the central opening 94 if the spring 32 is released by cable failure 28 and leads the fastener 68 against the annular impact receiving member 92. The end connection 64 can then strike and perhaps be contained by the stop bar 102. With reference to fig. 6, in the case of a fault, the fastener 68, urged by the spring 32, collides with the annular impact receiving plate member 92 and the end connection 64 passes through the central hole 94 defined in the plate member 92 annular impact receiver. In response to impact, the deformable support members 86 are plastically deformed to absorb much of the energy transferred from the spring 32 by the impact. The material from which the deformable support members are made is quite malleable to absorb the maximum energy caused by such an impact by bending, by rolling the "U" curve along the deformable members 86 similar to a strip, instead of fracturing it. Any part, such as the end connection 64, which passes through the central opening 94 in the impact receiving member 92 will come into contact with the stop bar 102 and will thus be maintained from simply passing freely out of the guide tube 56. With reference now to figs. 7A and 7B, the inner surface 114 of the lower portion of each 84 clamping bar can be chamfered. The beveled end 114 creates additional space in which the deformable support members 86 can deform in the event of an impact, as shown in FIG. 7B. In a pre-impact condition, as shown in FIG. 7A, a portion of the removable end 106 of the deformable support member 86 is not in contact with the beveled end 114. When an impact occurs, the deformable support member 86 can be bent to deform a greater distance in a radial direction with respect to a deformable member 86 supported by a clamping bar 84 with a non-bevelled end. Terms and expressions that have been used in the foregoing description are used herein as terms of description and not limitation, and there is no intent in the use of terms and expressions to exclude equivalents of the features shown and described or portions thereof. it will be recognized that the scope of the invention is defined and limited only by the following claims.

Claims (10)

1. An energy absorbing device for use in conjunction with a counterweight device, comprising: (a) a base; (b) an impact receiving member having a first face and a second opposite face, the impact receiving member is supported on a base adjacent to the base; and (c) a plurality of deformable support members each attached to the impact member and interconnected with the base, the deformable support members are arranged to be deformed by an impact on the first face and thus absorb energy from an impact on the first impact face of the impact receiving member. The energy absorbing device according to claim 1, characterized in that the deformable support members are plastically deformed by absorbing the impact energy. The energy absorbing device according to claim 1, characterized in that the base includes a collar defining an interior space and the impact receiving member is retained within such inner space by means of deformable support means before receiving an impact. The energy absorbing device according to claim 1, characterized in that the deformable support members are U-shaped. The energy absorption device according to claim 1, characterized in that the deformable support members are unite the impact receiving member in separate positions. The energy absorbing device according to claim 1, characterized in that the deformable support members are detachably attached to the base. The energy absorbing device according to claim 1, characterized in that the deformable support members are fixedly joined to the impact receiving member. The energy absorbing device according to claim 1, characterized in that the counterweight device includes a spring and a cable arranged to charge the spring, and wherein the impact receiving member is located in a probable spring path if the cable fails under load. 9. A counterweight device, comprising: (a) a force generating element and a tension carrying member, force generating element is interconnected with the tension carrying member; (b) a guide tube that at least partially surrounds a portion of the force generating element and the tension carrying member; (c) a collar mounted on one end of the guide tube; (d) an impact receiving member mounted adjacent the end of the guide tube, and having a first face directed towards the force generating element and having a second opposing face; and (e) a plurality of deformable support members attached to the second face of the impact receiving member and interconnected with the collar, the deformable support members are arranged to absorb energy and be deformed by an impact of the force generating element against the first face of the impact receiving member and thereby prevent damage to other portions of the counterweight apparatus in the event of a failure of the tension carrying member. The counterweight apparatus according to claim 9, characterized in that the impact receiving member and the deformable support members are interconnected with the collar by means of fasteners whereby the deformable support members are replaceable.