US20010011648A1 - Shock absorbing tow bar for trolley-type conveyor systems - Google Patents
Shock absorbing tow bar for trolley-type conveyor systems Download PDFInfo
- Publication number
- US20010011648A1 US20010011648A1 US09/832,400 US83240001A US2001011648A1 US 20010011648 A1 US20010011648 A1 US 20010011648A1 US 83240001 A US83240001 A US 83240001A US 2001011648 A1 US2001011648 A1 US 2001011648A1
- Authority
- US
- United States
- Prior art keywords
- component
- brake
- tow bar
- relative
- shock absorbing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64F—GROUND OR AIRCRAFT-CARRIER-DECK INSTALLATIONS SPECIALLY ADAPTED FOR USE IN CONNECTION WITH AIRCRAFT; DESIGNING, MANUFACTURING, ASSEMBLING, CLEANING, MAINTAINING OR REPAIRING AIRCRAFT, NOT OTHERWISE PROVIDED FOR; HANDLING, TRANSPORTING, TESTING OR INSPECTING AIRCRAFT COMPONENTS, NOT OTHERWISE PROVIDED FOR
- B64F1/00—Ground or aircraft-carrier-deck installations
- B64F1/22—Ground or aircraft-carrier-deck installations installed for handling aircraft
- B64F1/224—Towing bars
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61B—RAILWAY SYSTEMS; EQUIPMENT THEREFOR NOT OTHERWISE PROVIDED FOR
- B61B10/00—Power and free systems
- B61B10/02—Power and free systems with suspended vehicles
- B61B10/022—Vehicles; trolleys
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F7/00—Vibration-dampers; Shock-absorbers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F2230/00—Purpose; Design features
- F16F2230/16—Purpose; Design features used in a strut, basically rigid
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F2232/00—Nature of movement
Definitions
- the present invention relates generally to cushioning devices, such as shock absorbers, for cushioning movement between two relatively moveable structures. More specifically, the present invention concerns a cushioning device that is particularly suitable for use as a tow bar in a trolley-type conveyor system (e.g., a power and free conveyor system).
- a trolley-type conveyor system e.g., a power and free conveyor system.
- a moving structure is likely to experience shock (e.g., sudden acceleration or deceleration), and it is often desirable to absorb and cushion the shock so that untoward loading and consequential wear or damage of the structure is avoided. Accordingly, movement of the structure is often cushioned relative to some other structure. This is typically accomplished by providing a cushioning device between the two structures.
- traditional cushioning devices present numerous problems.
- a conveyor system involves a so-called “power and free conveyor system”, wherein a power track provides power to the conveyor system and the free track carries the loads and is selectively coupled to the power track for moving the loads along the conveyor path.
- the free track traditionally includes a load carrier comprising a drive unit that is selectively connected to the power track, a load-supporting unit for supporting an item, and a tow bar interconnecting the units.
- the drive unit is simultaneously disconnected from the power track and stopped, which consequently requires the load-supporting unit and the item supported thereon to suddenly decelerate. It is important that this shock be absorbed so that damage to the conveyor system and item is avoided.
- the absorbed energy is not stored (e.g., as would normally be the case when a spring is used to absorb the energy); otherwise, the stored energy will likely cause the carrier to lunge forwardly which can be damaging to the conveyor components and supported item and dangerous.
- the tow bar used in a traditional power and free conveyor system consequently includes structure that attempts to absorb the shock loads between the drive unit and the load-supporting unit.
- conventional tow bars are simply incapable of effectively diffusing the shock loads between the drive and load-supporting units.
- conventional tow bars often have complex and/or expensive constructions and fail to provide the durability needed in most conveyor system environments.
- a tow bar is preferably adjustable so that the various ranges of shock loads can be accommodated; that is to say, a tow bar preferably permits user adjustment of the amount of resistance it provides to relative movement between the drive and load-supporting units.
- the tow bar permits the tow bar to be used with various load sizes (i.e., the tow bar can be used with variously sized items carried on the load-supporting unit).
- the tow bar can be used with variously sized items carried on the load-supporting unit.
- most conventional tow bars designed to permit adjustment of the shock absorption in fact, provide little, if any, effective adjustability.
- an important object of the present invention is to provide an improved cushioning device that overcomes the problems associated with the prior art.
- Another important object of the present invention is to provide a cushioning device that is particularly effective as a shock absorbing tow bar in a conveyor system.
- an important object of the present invention to provide a tow bar having an inexpensive, simple and durable construction.
- a shock absorbing tow bar that is highly adjustable so that it may be used in various applications.
- the present invention concerns a cushioning device that includes a pair of shiftably interconnected components.
- a shock absorbing tow bar one of the components is connected to the drive unit of the load carrier and the other is connected to the load-supporting unit.
- the components are threadably intercoupled so that relative shifting of the components requires a screwing or unscrewing action that serves to cushion movement between the drive unit and load-supporting unit.
- FIG. 1 is a fragmentary vertical sectional view of a power and free conveyor system including a load carrier that is provided with a shock absorbing tow bar constructed in accordance with the principles of the present invention
- FIG. 2 is a vertical sectional view taken along line 2 - 2 of FIG. 1;
- FIG. 3 is a sectional view of the shock absorbing tow bar, with the outer cylinder being sectioned to reveal the inner cylinder;
- FIG. 4 is a cross-sectional view taken along line 4 - 4 of FIG. 3, particularly illustrating the tow bar in an extended condition
- FIG. 5 is a cross-sectional view similar to FIG. 4, but illustrating the tow bar in a retracted condition
- FIG. 6 is a cross-sectional view taken along 6 - 6 of FIG. 3, particularly illustrating the construction of the brake mechanism
- FIG. 7 is a cross-sectional view taken along 7 - 7 of FIG. 5, particularly illustrating the guide block slidably receiving the externally threaded bar fixed to the outer cylinder;
- FIG. 8 is an elevational view of the left end of the tow bar shown in FIG. 3;
- FIG. 9 is an elevational view of the right end of the tow bar shown in FIG. 3.
- the conveyor system 10 selected for illustration generally includes a power track 12 and an upwardly spaced free track 14 .
- the power track 12 provides power to the conveyor system 10
- the free track 14 carries the loads and is selectively coupled to the power track 20 for moving the loads along the conveyor path.
- the illustrated embodiment comprises a so-called power and free conveyor system.
- the principles of the present invention are equally applicable to various other conveyor systems and additional applications.
- the principles of the present invention may be utilized in an overhead power and free system, in a tilt table to cushion shock loads exerted against the table, etc.
- the illustrated conveyor system 10 has a generally standard construction except for those inventive features described hereinbelow. It shall therefore be sufficient to explain that the power track 12 includes a rail 16 defined by two opposed, spaced apart C-shaped channels 18 and 20 (see FIG. 2). A plurality of spaced apart, wheeled power trolleys 22 ride along the length of the power rail 16 .
- the power trolleys 22 cooperatively carry an endless drive chain 24 above the rail 16 , and the chain is provided with a plurality of spaced apart pusher dogs 26 .
- a suitable power source such as a motor (not shown), is provided to propel the trolleys 22 and chain 24 along the rail 16 .
- the trolleys 22 and chain 24 are driven leftwardly as depicted by arrow 28 .
- the power track 12 continuously runs so that driving power for the free track 14 is always available.
- the free track 14 similarly includes a rail 30 defined by two opposed, spaced apart C-shaped channels 32 and 34 (see FIG. 2).
- the free track 14 includes a plurality of similarly constructed load carriers 36 (only one being shown in FIGS. 1 and 2), each of which supports and moves an item (not shown) along the length of the conveyor system 10 .
- the carrier 36 includes an accumulating trolley 38 and a load carriage 40 connected in a trailing relationship to the accumulating trolley 38 .
- the accumulating trolley 38 is configured to be selectively coupled to the drive chain 24 for moving the carrier 36 along the length of the conveyor system 10
- the load carriage 40 is designed to support an item (not shown) thereon.
- the accumulating trolley 38 includes a body 42 supported by load wheels 44 (only three being shown in FIGS. 1 and 2) which ride in respective ones of the channels 18 and 20 .
- a pair of guide rollers 46 are mounted to the body 42 for rotation about respective axes that are perpendicular to the rotational axes of the load wheels 44 . As perhaps best shown in FIG. 2, the guide rollers 46 are aligned with the upper flanges of the channels 18 and 20 to maintain the proper lateral orientation of the body 42 within the rail 16 .
- a pair of attachment straps 48 and 50 project rearwardly from the body 42 for purposes which will subsequently be described.
- the trolley 38 further includes a stop mechanism 52 swingably mounted to the body 42 at pivot 54 .
- Adjacent the rear end of the mechanism 52 is a pair of spaced apart, downwardly projecting lugs 56 and 58 defining a space therebetween which is configured to receive the pusher dog 26 therein, as shown in FIG. 1.
- the stop mechanism 52 is shown in an engaged position in FIG. 1 , wherein the pusher dog 26 is received between the lugs 56 , 58 and engages the forward lug 56 to drive the accumulating trolley 38 along the rail 30 .
- the rearward lug 58 is provided to prevent forward movement of the trolley 38 beyond the pusher dog 26 , which is particularly useful in maintaining the interengagement of the stop mechanism 52 and pusher dog 26 when the rails 16 , 30 slope downwardly.
- the stop mechanism 52 is normal to routinely stop the load carrier 36 and the stop mechanism 52 must consequently be disengeable from the pusher dog 26 . This is accomplished simply by swinging the mechanism 52 in a counterclockwise direction (when viewing FIG. 1) to a disengaged position (not shown). In the disengaged position, the lugs 56 , 58 are swung out of engagement with the pusher dog 26 . In the usual manner, the stop mechanism 52 is provided with a forwardmost engagement tab 60 . When it is desired to stop the load carrier 36 , a bracket (not shown) is simply positioned to engage the tab 60 and force it downwardly so that the stop mechanism 52 is swung to the disengaged position.
- each carrier 36 includes means for similarly swinging the stop mechanism of a trailing carrier to the disengaged position so that carriers which encounter a stopped carrier will also be stopped. It is also noted that the stop mechanism 52 is normally biased to the engaged position and is prevented from clockwise movement (when viewing FIG. 1) beyond the engaged position.
- the load carriage 40 includes an intermediate trolley 62 and a trailing trolley 64 spaced from the intermediate trolley 62 in a rearward direction relative to the direction of travel (see arrow 28 ).
- the trolleys 62 , 64 are similar in construction to the accumulating trolley 38 .
- the intermediate trolley 62 includes a body 66 supported by load wheels 68 (only two being shown in FIG. 1) and laterally oriented within the rail 30 by guide rollers 70 .
- the trolley 72 also includes a pair of attachment straps 72 (only one being shown in FIG. 1) for purposes which will subsequently be described.
- the intermediate trolley 62 differs from the accumulating trolley 38 because the former does not include a stop mechanism.
- the intermediate trolley 62 includes a load pin 74 projecting upwardly from body 66 and supported thereby for relative rotational movement about its longitudinal axis.
- a pair of pillow boxes 76 , 78 are supported on a horizontal pivot pin 80 fixed to the upper end of the load pin 74 .
- a rearwardly projecting stop mechanism engagement bracket 82 is also provided on the intermediate trolley 62 , although the bracket 82 is unnecessary and may be removed if desired.
- the trailing trolley 64 is virtually identical in construction to the intermediate trolley 62 , except for the fact that the trailing trolley 64 does not include forwardly projecting attachment straps.
- the trailing trolley 64 includes a body 84 supported by load wheels 86 and laterally oriented by guide rollers 88 .
- a load pin 90 projects upwardly from the body 84 and swingably supports a pair of pillow boxes 92 (only one being shown in FIG. 1).
- a stop bracket 94 projects rearwardly from the body 84 and defines the rearwardmost part of the carrier 36 within the rail 30 .
- the stop bracket 94 of the trailing trolley 64 is operational and, more importantly, serves to stop the trailing load carrier (not shown) when the illustrated load carrier 36 is stopped. Particularly, when the load carrier 36 shown in FIG. 1 is stopped, as described above, the trailing load carrier will continue forwardly until the stop mechanism of its accumulating trolley engages the bracket 94 of the illustrated trailing trolley 64 , whereupon the trailing carrier will also be disengaged from the power track 12 and thereby stopped.
- the load carriage 40 also includes a support table 96 that interconnects the intermediate and trailing trolleys 62 and 64 and is supported therebetween.
- the table 96 includes a top support plate 98 on which an item (not shown) may be supported.
- a pair of pedestals 100 and 102 are connected between the plate 98 and pillow boxes 76 , 78 and 92 of the respective trolleys 62 and 64 . It will be appreciated that the rotatable movement of the load pins 74 , 90 and pillow boxes 76 , 78 , 92 accommodates for grades and turns along the conveyor path.
- the present invention particularly concerns a tow bar 104 that connects the load carriage 40 to the accumulating trolley 38 and serves to cushion movement therebetween.
- the tow bar 104 provides means for gradually decelerating the load carriage 40 .
- the preferred tow bar 104 includes two telescopically interfitted tubular cylinders 106 and 108 .
- the cylinders 106 and 108 are connected to the accumulating and intermediate trolleys 38 and 62 by respective gimble-type attachments that accommodate for grades and turns along the conveyor path.
- the inner cylinder 106 includes a pair of attachment ears 110 and 112 (see also FIG. 8) between which a block 114 is secured by a nut and bolt assembly 116 (see FIG. 1).
- the assembly 116 permits relative pivoting movement between the block 114 and ears 110 , 112 .
- a nut and bolt assembly 118 similarly attaches the straps 48 , 50 of the accumulating trolley 38 to the block 114 .
- the assemblies 116 and 118 therefore define relatively perpendicular pivot axes at the attachment point between the tow bar 104 and accumulating trolley 38 .
- a pair of attachment ears 120 , 122 are fixed to the opposite end of the outer cylinder 108 .
- the ears 120 , 122 are attached to the straps 72 of the intermediate trolley 62 by a relatively pivotable block 124 and nut and bolt assemblies 126 and 128 , as shown in FIG. 1.
- Movement of the cylinders 106 and 108 is generally limited to shifting along the longitudinal axis of the tow bar 104 (i.e., telescopic extension and retraction of the tow bar) and relative rotation as will subsequently be described. If desired, it may be possible to utilize various other tubular shapes (e.g., a polygonal cross-sectional shape) as an alternative to the illustrated cylindrical shape, particularly when there is no requirement for relative rotation between the ends of the tow bar 104 . It is also noted that, because of the preferred tubular nature of the illustrated cylinders 106 and 108 , an internal chamber 130 is defined by the tow bar 104 . As will subsequently be described, the chamber 130 contains the mechanism that serves to diffuse shock loads between the accumulating trolley 38 and intermediate trolley 62 .
- a guide block 132 is mounted adjacent the concealed end of the cylinder 106 .
- the guide block 132 is fixed to the cylinder 106 by four screws 134 projecting radially through the cylinder 106 and into the block 132 .
- the illustrated screws 134 are threadably received within the block 132 and are spaced equally about the circumference of the cylinder 106 .
- the block 132 presents a central, square-shaped opening 136 .
- a mounting block 138 is similarly mounted to the cylinder 106 adjacent the exposed end thereof.
- the block 138 is fixed in place by four screws 140 (only two of the screws being shown in the drawing figures) which are spaced equally about the circumference of the cylinder 106 and project radially inward through the cylinder 106 and into threaded engagement with the block 138 (see FIGS. 4 and 5).
- a central opening 142 is defined in the block 138 , and a bar 144 is fixed in the opening 142 by suitable means (e.g., welding, press fit, adhesive, threaded interengagement).
- the bar 144 has a circular cross-sectional shape and is positioned by the block 138 in axial alignment with the cylinder 106 .
- the bar 144 includes an externally threaded section 144 a that projects inwardly from the distal end of the bar 144 . It is also noted that the illustrated screws 140 terminate short of the bar 144 and therefore do not serve to attach the bar 144 to the block 138 and cylinder 106 , although the use of screws providing such attachment is entirely within the ambit of the present invention.
- the outer cylinder 108 is also associated with a concentric bar 146 that similarly includes an innermost, externally threaded section 146 a (see FIGS. 4 and 5). However, contrary to the bar 144 , the bar 146 has a square-shaped central section 146 b slidably received within the opening 136 of the guide block 132 . In addition, adjacent the end of the bar 144 opposite from the externally threaded section 146 a is a cylindrical outermost section 146 c having standard screw threads defined partly along the length thereof. The cylindrical section 146 c has a relatively smaller cross-sectional shape than the square-shaped section 146 b , such that a shoulder is defined at the transition of these sections.
- a bushing 148 is received on the cylindrical section 146 c between a pair of washers 150 and 152 . These components (i.e., the bushing 148 and the washers 150 , 152 ) are secured against the shoulder by a nut 154 screwed onto the section 146 c .
- a disk 156 is positioned between the washers 150 and 152 and is fixed to the inside of the outer cylinder 108 .
- the foregoing arrangement prevents the bar 146 from shifting axially relative to the cylinder 108 but permits relative rotational movement between the bar 146 and cylinder 108 .
- the corresponding polygonal shape of the bar 146 and opening 136 in the guide block 132 prevents relative rotational movement between the bar 146 and guide block 132 .
- the bar 146 is rotationally fixed relative to the cylinder 106 , although the cylinders 106 and 108 are permitted to rotate relative to one another.
- a stop 158 preferably in the form of a circular washer having a square-shaped central opening, is fixed by suitable means (e.g., welding) to the central section 146 b of the bar 146 .
- the washer 150 and the stop 158 are positioned at relatively stationary locations on opposite sides of the guide block 132 and are configured for abutting interengagement with the block 132 (see FIGS. 5 and 4, respectively). In this respect, the washer 150 and stop 158 serve to limit relative sliding movement between the bar 146 and guide block 132 .
- the stop washers 150 , 158 and guide block 132 also limit relative axial shifting of the cylinders 106 and 108 . That is to say, the interengagement of the guide block 132 and washer 150 limits retraction of the tow bar 104 (see FIG. 5), while interengagement of the guide block 132 and washer 158 limits extension of the tow bar 104 (see FIG. 4). As shown in FIG. 5, the tow bar 104 is arranged so that the bars 144 and 146 do not contact one another when the tow bar is fully retracted.
- the bars 144 and 146 shift relative to one another during corresponding shifting of the cylinders 106 and 108 .
- the bars 144 and 146 are coaxial so that the externally threaded sections 144 a and 146 a are located on a common thread axis along which relative shifting of the bars occurs.
- the axial alignment of the bars 144 and 146 is facilitated by the fact that both bars are directly coupled to the same cylinder 106 by the respective blocks 138 and 132 .
- the bars 144 and 146 have a common thread pitch, although the threads are oppositely inclined (i.e., the bar 144 is provided with a left-handed thread and the bar 146 is provided with a right-handed thread).
- the threads of both bars 144 and 146 are a so-called “parallel screw thread”. It may be said that the threaded sections 144 a and 146 a are essentially mirror images of one another.
- the tow bar 104 further includes a cylindrical-shaped, internally threaded spool 160 that threadably receives the threaded sections 144 a and 146 a of the bars 144 and 146 .
- the internal face of the spool 160 is provided with oppositely inclined threaded sections 160 a and 160 b for threadably engaging the respective bar sections 144 a and 146 a .
- the spool 160 is consequently disposed along the same thread axis as the bars 144 and 146 and has internal threads with the same pitch as the threads of the bars 144 , 146 . Thus, when the bars 144 and 146 shift relative to one another along the thread axis, the spool is required to rotate relative to the bars.
- the spool 160 progressively screws onto the threaded sections 144 a and 146 a .
- the spool 160 progressively unscrews along the threaded sections 144 a and 146 a .
- the opposite inclination of the threads provides the simultaneous screwing or unscrewing action of the spool 160 relative to the threaded sections 144 a and 146 a . It is noted that the spool 160 is of sufficient length to avoid disconnection from the bars 144 and 146 when the tow bar 104 is fully extended (see FIG. 4).
- the spool 160 serves to check relative axial movement of the cylinders 106 and 108 . That is to say, the tow bar 104 is not freely extendable and retractable, but rather relative axial shifting of the cylinders 106 and 108 requires spinning of the spool 160 and thereby a screwing or unscrewing action cooperatively presented by the bars 144 , 146 and spool 160 . This action absorbs energy and consequently diffuses any forces that might cause the tow bar 104 to extend or retract. Moreover, the absorbed energy is not stored by the tow bar 104 .
- the coaction of the bars 144 , 146 and spool 160 do not create a reactionary force to that exerted on the tow bar 104 .
- a load causes retraction of the tow bar 104
- the bars 144 , 146 and spool 160 are preferably machined from a high strength steel material.
- the remaining previously-described components of the tow bar 104 are also preferably formed of metal, although high strength steel may not be required. Standard fabrication techniques are preferably used to form these components (e.g., the cylinders 106 and 108 are preferably cast).
- a suitable thread arrangement for the bars 144 , 146 and spool 160 is a thread having an angle of 45°, a pitch corresponding to one complete thread turn for every 1 7 ⁇ 8 inches along the thread axis, and an approximately ⁇ fraction (5/16) ⁇ inch square cross-sectional shape. It has been determined that a tow bar having such a thread arrangement is capable of absorbing the loads generated by items weighing as much as 12,500 lbs.
- the tow bar 104 is preferably provided with means for permitting adjustment of the resistance to tow bar extension and retraction. As indicated above, such adjustment permits the tow bar 104 to be used in various load applications. For example, the resistance to tow bar extension and retraction is increased when a relatively heavy load is carried on the support table 96 . On the other hand, the resistance can be decreased when a relatively lighter load is carried on the table 96 .
- the tow bar 104 is provided with a brake mechanism 164 configured to adjustably restrain rotation of the spool 160 . As perhaps best shown in FIG. 6, the brake mechanism 164 includes a pair of pads 166 and 168 which are yieldably pressed against the cylindrical outer surface 170 of the spool 160 .
- the pads are preferably formed of a material similar to that used in automotive brake pads 166 and 168 (e.g., an asbestos material), although other suitable materials may be used.
- the pads 166 and 168 are prevented from rotating with the spool 160 as a result of being contained within respective sleeves 172 and 174 .
- the sleeves 172 and 174 project through the wall of the inner cylinder 106 and are positioned in such a manner that the pads 166 and 168 are urged against the spool 160 at diametrically opposite locations. It will be appreciated that this reduces the risk of shifting the spool 160 off the thread axis which might lock or, at the very least, unduly restrict extension and retraction of the tow bar 104 .
- Threaded caps 176 and 178 are provided in the respective sleeves 172 and 174 , as well as spring washers 180 and 182 . Inward screwing of the caps 176 and 178 cause the pads 166 and 168 to exert greater forces against the spool 160 , while unscrewing of the caps 176 and 178 relieves the forces exerted against the spool 160 by the pads 166 and 168 . In other words, inward screwing of the caps 176 and 178 provides greater resistance to spool rotation and the tow bar 104 is consequently capable of absorbing relatively greater loads. On the other hand, unscrewing of the caps 176 and 178 provides less resistance to spool rotation and the tow bar 104 can only absorb relatively smaller loads.
- the tow bar 104 slowly extends and the carriage 40 is gradually accelerated to the speed of the accumulating trolley 38 .
- the tow bar 104 will extend to the fully extended position shown in FIG. 4, such that the full stroke of the tow bar 104 will be available to absorb the energy generated the next time the carrier 36 is suddenly stopped.
Abstract
A shock absorbing tow bar for connection between the accumulating trolley and load carriage of a power and free conveyor system is disclosed. The tow bar includes one component that is connectable to the accumulating trolley and another that is connectable to the intermediate trolley of the load carriage. Limited relative shifting is permitted between the components of the tow bar. Moreover, the components are threadably intercoupled so that such relative shifting requires a screwing or unscrewing action that serves to cushion movement between the accumulating trolley and load carriage.
Description
- This is a continuation application of U.S. Ser. No. 09/404,899; Filed on Sep. 24, 1999, which is incorporated by reference herein.
- 1. Field of the Invention
- The present invention relates generally to cushioning devices, such as shock absorbers, for cushioning movement between two relatively moveable structures. More specifically, the present invention concerns a cushioning device that is particularly suitable for use as a tow bar in a trolley-type conveyor system (e.g., a power and free conveyor system).
- 2. Discussion of Prior Art
- A moving structure is likely to experience shock (e.g., sudden acceleration or deceleration), and it is often desirable to absorb and cushion the shock so that untoward loading and consequential wear or damage of the structure is avoided. Accordingly, movement of the structure is often cushioned relative to some other structure. This is typically accomplished by providing a cushioning device between the two structures. However, traditional cushioning devices present numerous problems.
- These problems are particularly evident in conveyor systems having a series of load carriers that are routinely stopped along the length of the conveyor system. It will be appreciated that such conveyor systems are often used in assembly lines and stoppage of the load carriers permits various steps to be performed at assembly stations spaced along the conveyor line. Furthermore, the carriers will often support large, heavy items (e.g., an automobile) and stoppage of the carriers must account for the momentum of not only the carrier but also the item supported thereon. It is also noted that starting and stopping of the load carrier at each of the stations is typically sudden so as to provide, among other things, less travel time between stations.
- One example of such a conveyor system involves a so-called “power and free conveyor system”, wherein a power track provides power to the conveyor system and the free track carries the loads and is selectively coupled to the power track for moving the loads along the conveyor path. The free track traditionally includes a load carrier comprising a drive unit that is selectively connected to the power track, a load-supporting unit for supporting an item, and a tow bar interconnecting the units. Traditionally, the drive unit is simultaneously disconnected from the power track and stopped, which consequently requires the load-supporting unit and the item supported thereon to suddenly decelerate. It is important that this shock be absorbed so that damage to the conveyor system and item is avoided. It is also important that the absorbed energy is not stored (e.g., as would normally be the case when a spring is used to absorb the energy); otherwise, the stored energy will likely cause the carrier to lunge forwardly which can be damaging to the conveyor components and supported item and dangerous.
- The tow bar used in a traditional power and free conveyor system consequently includes structure that attempts to absorb the shock loads between the drive unit and the load-supporting unit. However, it is believed that conventional tow bars are simply incapable of effectively diffusing the shock loads between the drive and load-supporting units. Moreover, conventional tow bars often have complex and/or expensive constructions and fail to provide the durability needed in most conveyor system environments. Furthermore, a tow bar is preferably adjustable so that the various ranges of shock loads can be accommodated; that is to say, a tow bar preferably permits user adjustment of the amount of resistance it provides to relative movement between the drive and load-supporting units. It will be appreciated that such adjustability permits the tow bar to be used with various load sizes (i.e., the tow bar can be used with variously sized items carried on the load-supporting unit). However, it is also believed that most conventional tow bars designed to permit adjustment of the shock absorption, in fact, provide little, if any, effective adjustability.
- Responsive to these and other problems, an important object of the present invention is to provide an improved cushioning device that overcomes the problems associated with the prior art. Another important object of the present invention is to provide a cushioning device that is particularly effective as a shock absorbing tow bar in a conveyor system. In this respect, an important object of the present invention to provide a tow bar having an inexpensive, simple and durable construction. It is also an important object of the present invention to provide a shock absorbing tow bar that is highly adjustable so that it may be used in various applications.
- In accordance with these and other objects evident from the following description of the preferred embodiment, the present invention concerns a cushioning device that includes a pair of shiftably interconnected components. As a shock absorbing tow bar, one of the components is connected to the drive unit of the load carrier and the other is connected to the load-supporting unit. Moreover, the components are threadably intercoupled so that relative shifting of the components requires a screwing or unscrewing action that serves to cushion movement between the drive unit and load-supporting unit.
- Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiment and the accompanying drawing figures.
- A preferred embodiment of the invention is described in detail below with reference to the attached drawing figures, wherein:
- FIG. 1 is a fragmentary vertical sectional view of a power and free conveyor system including a load carrier that is provided with a shock absorbing tow bar constructed in accordance with the principles of the present invention;
- FIG. 2 is a vertical sectional view taken along line2-2 of FIG. 1;
- FIG. 3 is a sectional view of the shock absorbing tow bar, with the outer cylinder being sectioned to reveal the inner cylinder;
- FIG. 4 is a cross-sectional view taken along line4-4 of FIG. 3, particularly illustrating the tow bar in an extended condition;
- FIG. 5 is a cross-sectional view similar to FIG. 4, but illustrating the tow bar in a retracted condition;
- FIG. 6 is a cross-sectional view taken along6-6 of FIG. 3, particularly illustrating the construction of the brake mechanism;
- FIG. 7 is a cross-sectional view taken along7-7 of FIG. 5, particularly illustrating the guide block slidably receiving the externally threaded bar fixed to the outer cylinder;
- FIG. 8 is an elevational view of the left end of the tow bar shown in FIG. 3; and
- FIG. 9 is an elevational view of the right end of the tow bar shown in FIG. 3.
- Turning initially to FIGS. 1 and 2, the
conveyor system 10 selected for illustration generally includes apower track 12 and an upwardly spacedfree track 14. Thepower track 12 provides power to theconveyor system 10, while thefree track 14 carries the loads and is selectively coupled to the power track 20 for moving the loads along the conveyor path. In this respect, the illustrated embodiment comprises a so-called power and free conveyor system. However, the principles of the present invention are equally applicable to various other conveyor systems and additional applications. For example, the principles of the present invention may be utilized in an overhead power and free system, in a tilt table to cushion shock loads exerted against the table, etc. - With the foregoing caveat in mind, the illustrated
conveyor system 10 has a generally standard construction except for those inventive features described hereinbelow. It shall therefore be sufficient to explain that thepower track 12 includes arail 16 defined by two opposed, spaced apart C-shaped channels 18 and 20 (see FIG. 2). A plurality of spaced apart,wheeled power trolleys 22 ride along the length of thepower rail 16. Thepower trolleys 22 cooperatively carry anendless drive chain 24 above therail 16, and the chain is provided with a plurality of spaced apartpusher dogs 26. In the usual manner, a suitable power source, such as a motor (not shown), is provided to propel thetrolleys 22 andchain 24 along therail 16. In the illustrated embodiment, thetrolleys 22 andchain 24 are driven leftwardly as depicted byarrow 28. During operation, thepower track 12 continuously runs so that driving power for thefree track 14 is always available. - The
free track 14 similarly includes arail 30 defined by two opposed, spaced apart C-shaped channels 32 and 34 (see FIG. 2). However, thefree track 14 includes a plurality of similarly constructed load carriers 36 (only one being shown in FIGS. 1 and 2), each of which supports and moves an item (not shown) along the length of theconveyor system 10. Generally speaking, thecarrier 36 includes an accumulatingtrolley 38 and aload carriage 40 connected in a trailing relationship to the accumulatingtrolley 38. As will subsequently be described, the accumulatingtrolley 38 is configured to be selectively coupled to thedrive chain 24 for moving thecarrier 36 along the length of theconveyor system 10, and theload carriage 40 is designed to support an item (not shown) thereon. - The accumulating
trolley 38 includes abody 42 supported by load wheels 44 (only three being shown in FIGS. 1 and 2) which ride in respective ones of thechannels 18 and 20. A pair ofguide rollers 46 are mounted to thebody 42 for rotation about respective axes that are perpendicular to the rotational axes of theload wheels 44. As perhaps best shown in FIG. 2, theguide rollers 46 are aligned with the upper flanges of thechannels 18 and 20 to maintain the proper lateral orientation of thebody 42 within therail 16. A pair of attachment straps 48 and 50 project rearwardly from thebody 42 for purposes which will subsequently be described. Thetrolley 38 further includes astop mechanism 52 swingably mounted to thebody 42 atpivot 54. Adjacent the rear end of themechanism 52 is a pair of spaced apart, downwardly projectinglugs pusher dog 26 therein, as shown in FIG. 1. It will be appreciated that thestop mechanism 52 is shown in an engaged position in FIG. 1, wherein thepusher dog 26 is received between thelugs forward lug 56 to drive the accumulatingtrolley 38 along therail 30. Therearward lug 58 is provided to prevent forward movement of thetrolley 38 beyond thepusher dog 26, which is particularly useful in maintaining the interengagement of thestop mechanism 52 andpusher dog 26 when therails load carrier 36 and thestop mechanism 52 must consequently be disengeable from thepusher dog 26. This is accomplished simply by swinging themechanism 52 in a counterclockwise direction (when viewing FIG. 1) to a disengaged position (not shown). In the disengaged position, thelugs pusher dog 26. In the usual manner, thestop mechanism 52 is provided with aforwardmost engagement tab 60. When it is desired to stop theload carrier 36, a bracket (not shown) is simply positioned to engage thetab 60 and force it downwardly so that thestop mechanism 52 is swung to the disengaged position. The bracket also serves to hold thestop mechanism 52 and thereby check further forward movement of thecarrier 36. As will be described below, eachcarrier 36 includes means for similarly swinging the stop mechanism of a trailing carrier to the disengaged position so that carriers which encounter a stopped carrier will also be stopped. It is also noted that thestop mechanism 52 is normally biased to the engaged position and is prevented from clockwise movement (when viewing FIG. 1) beyond the engaged position. - The
load carriage 40 includes anintermediate trolley 62 and a trailingtrolley 64 spaced from theintermediate trolley 62 in a rearward direction relative to the direction of travel (see arrow 28). Thetrolleys trolley 38. - Particularly, the
intermediate trolley 62 includes abody 66 supported by load wheels 68 (only two being shown in FIG. 1) and laterally oriented within therail 30 byguide rollers 70. Thetrolley 72 also includes a pair of attachment straps 72 (only one being shown in FIG. 1) for purposes which will subsequently be described. However, theintermediate trolley 62 differs from the accumulatingtrolley 38 because the former does not include a stop mechanism. Furthermore, theintermediate trolley 62 includes aload pin 74 projecting upwardly frombody 66 and supported thereby for relative rotational movement about its longitudinal axis. A pair ofpillow boxes horizontal pivot pin 80 fixed to the upper end of theload pin 74. A rearwardly projecting stopmechanism engagement bracket 82 is also provided on theintermediate trolley 62, although thebracket 82 is unnecessary and may be removed if desired. - The trailing
trolley 64 is virtually identical in construction to theintermediate trolley 62, except for the fact that the trailingtrolley 64 does not include forwardly projecting attachment straps. Thus it shall be sufficient to explain that the trailingtrolley 64 includes abody 84 supported byload wheels 86 and laterally oriented byguide rollers 88. Aload pin 90 projects upwardly from thebody 84 and swingably supports a pair of pillow boxes 92 (only one being shown in FIG. 1). Astop bracket 94 projects rearwardly from thebody 84 and defines the rearwardmost part of thecarrier 36 within therail 30. Contrary to theintermediate trolley 62, thestop bracket 94 of the trailingtrolley 64 is operational and, more importantly, serves to stop the trailing load carrier (not shown) when the illustratedload carrier 36 is stopped. Particularly, when theload carrier 36 shown in FIG. 1 is stopped, as described above, the trailing load carrier will continue forwardly until the stop mechanism of its accumulating trolley engages thebracket 94 of the illustrated trailingtrolley 64, whereupon the trailing carrier will also be disengaged from thepower track 12 and thereby stopped. - The
load carriage 40 also includes a support table 96 that interconnects the intermediate and trailingtrolleys top support plate 98 on which an item (not shown) may be supported. A pair ofpedestals plate 98 andpillow boxes respective trolleys pillow boxes - As noted above, forward movement of the
carrier 36 is halted by swinging thestop mechanism 52 to the disengaged position and virtually simultaneous retention of themechanism 52 against further forward movement. This requires extremely sudden deceleration of theload carriage 40 and any item(s) supported thereon, which can be damaging to the conveyor components and the supported item(s). The present invention particularly concerns atow bar 104 that connects theload carriage 40 to the accumulatingtrolley 38 and serves to cushion movement therebetween. In other words, thetow bar 104 provides means for gradually decelerating theload carriage 40. - As perhaps best shown in FIGS.3-5, the
preferred tow bar 104 includes two telescopically interfittedtubular cylinders cylinders intermediate trolleys inner cylinder 106 includes a pair ofattachment ears 110 and 112 (see also FIG. 8) between which ablock 114 is secured by a nut and bolt assembly 116 (see FIG. 1). As is customary, theassembly 116 permits relative pivoting movement between theblock 114 andears bolt assembly 118 similarly attaches thestraps trolley 38 to theblock 114. Theassemblies tow bar 104 and accumulatingtrolley 38. Similar to theinner cylinder 106, a pair ofattachment ears outer cylinder 108. Furthermore, theears straps 72 of theintermediate trolley 62 by a relativelypivotable block 124 and nut andbolt assemblies - Movement of the
cylinders tow bar 104. It is also noted that, because of the preferred tubular nature of the illustratedcylinders internal chamber 130 is defined by thetow bar 104. As will subsequently be described, thechamber 130 contains the mechanism that serves to diffuse shock loads between the accumulatingtrolley 38 andintermediate trolley 62. - Turning first to the
inner cylinder 106, aguide block 132 is mounted adjacent the concealed end of thecylinder 106. As perhaps best shown in FIG. 7, theguide block 132 is fixed to thecylinder 106 by fourscrews 134 projecting radially through thecylinder 106 and into theblock 132. The illustrated screws 134 are threadably received within theblock 132 and are spaced equally about the circumference of thecylinder 106. For purposes which will be described below, theblock 132 presents a central, square-shapedopening 136. A mountingblock 138 is similarly mounted to thecylinder 106 adjacent the exposed end thereof. Particularly, theblock 138 is fixed in place by four screws 140 (only two of the screws being shown in the drawing figures) which are spaced equally about the circumference of thecylinder 106 and project radially inward through thecylinder 106 and into threaded engagement with the block 138 (see FIGS. 4 and 5). Acentral opening 142 is defined in theblock 138, and abar 144 is fixed in theopening 142 by suitable means (e.g., welding, press fit, adhesive, threaded interengagement). As perhaps best shown in FIG. 8, thebar 144 has a circular cross-sectional shape and is positioned by theblock 138 in axial alignment with thecylinder 106. Thebar 144 includes an externally threadedsection 144 a that projects inwardly from the distal end of thebar 144. It is also noted that the illustratedscrews 140 terminate short of thebar 144 and therefore do not serve to attach thebar 144 to theblock 138 andcylinder 106, although the use of screws providing such attachment is entirely within the ambit of the present invention. - The
outer cylinder 108 is also associated with aconcentric bar 146 that similarly includes an innermost, externally threadedsection 146 a (see FIGS. 4 and 5). However, contrary to thebar 144, thebar 146 has a square-shapedcentral section 146 b slidably received within theopening 136 of theguide block 132. In addition, adjacent the end of thebar 144 opposite from the externally threadedsection 146 a is a cylindricaloutermost section 146 c having standard screw threads defined partly along the length thereof. Thecylindrical section 146 c has a relatively smaller cross-sectional shape than the square-shapedsection 146 b, such that a shoulder is defined at the transition of these sections. Abushing 148 is received on thecylindrical section 146 c between a pair ofwashers bushing 148 and thewashers 150,152) are secured against the shoulder by anut 154 screwed onto thesection 146 c. Adisk 156 is positioned between thewashers outer cylinder 108. The foregoing arrangement prevents thebar 146 from shifting axially relative to thecylinder 108 but permits relative rotational movement between thebar 146 andcylinder 108. However, the corresponding polygonal shape of thebar 146 andopening 136 in theguide block 132 prevents relative rotational movement between thebar 146 and guideblock 132. In this respect, thebar 146 is rotationally fixed relative to thecylinder 106, although thecylinders stop 158, preferably in the form of a circular washer having a square-shaped central opening, is fixed by suitable means (e.g., welding) to thecentral section 146 b of thebar 146. Thewasher 150 and thestop 158 are positioned at relatively stationary locations on opposite sides of theguide block 132 and are configured for abutting interengagement with the block 132 (see FIGS. 5 and 4, respectively). In this respect, thewasher 150 and stop 158 serve to limit relative sliding movement between thebar 146 and guideblock 132. Because theguide block 132 and bar 146 are prevented from shifting axially relative to therespective cylinders stop washers cylinders guide block 132 andwasher 150 limits retraction of the tow bar 104 (see FIG. 5), while interengagement of theguide block 132 andwasher 158 limits extension of the tow bar 104 (see FIG. 4). As shown in FIG. 5, thetow bar 104 is arranged so that thebars - As noted, the
bars cylinders bars sections bars same cylinder 106 by therespective blocks bars bar 144 is provided with a left-handed thread and thebar 146 is provided with a right-handed thread). It is also noted that the threads of bothbars sections - The
tow bar 104 further includes a cylindrical-shaped, internally threadedspool 160 that threadably receives the threadedsections bars spool 160 is provided with oppositely inclined threadedsections respective bar sections spool 160 is consequently disposed along the same thread axis as thebars bars bars tow bar 104 is retracted (e.g., thecylinders spool 160 progressively screws onto the threadedsections tow bar 104 is extended, thespool 160 progressively unscrews along the threadedsections spool 160 relative to the threadedsections spool 160 is of sufficient length to avoid disconnection from thebars tow bar 104 is fully extended (see FIG. 4). - Moreover, the
spool 160 serves to check relative axial movement of thecylinders tow bar 104 is not freely extendable and retractable, but rather relative axial shifting of thecylinders spool 160 and thereby a screwing or unscrewing action cooperatively presented by thebars spool 160. This action absorbs energy and consequently diffuses any forces that might cause thetow bar 104 to extend or retract. Moreover, the absorbed energy is not stored by thetow bar 104. In other words, the coaction of thebars spool 160 do not create a reactionary force to that exerted on thetow bar 104. For example, when a load causes retraction of thetow bar 104, there will not be stored energy that causes extension of thetow bar 104 once the load has been diffused or stopped. - The
bars spool 160 are preferably machined from a high strength steel material. The remaining previously-described components of thetow bar 104 are also preferably formed of metal, although high strength steel may not be required. Standard fabrication techniques are preferably used to form these components (e.g., thecylinders bars spool 160 is a thread having an angle of 45°, a pitch corresponding to one complete thread turn for every 1 ⅞ inches along the thread axis, and an approximately {fraction (5/16)} inch square cross-sectional shape. It has been determined that a tow bar having such a thread arrangement is capable of absorbing the loads generated by items weighing as much as 12,500 lbs. - The
tow bar 104 is preferably provided with means for permitting adjustment of the resistance to tow bar extension and retraction. As indicated above, such adjustment permits thetow bar 104 to be used in various load applications. For example, the resistance to tow bar extension and retraction is increased when a relatively heavy load is carried on the support table 96. On the other hand, the resistance can be decreased when a relatively lighter load is carried on the table 96. In the illustrated embodiment, thetow bar 104 is provided with abrake mechanism 164 configured to adjustably restrain rotation of thespool 160. As perhaps best shown in FIG. 6, thebrake mechanism 164 includes a pair ofpads outer surface 170 of thespool 160. The pads are preferably formed of a material similar to that used inautomotive brake pads 166 and 168 (e.g., an asbestos material), although other suitable materials may be used. Thepads spool 160 as a result of being contained withinrespective sleeves sleeves inner cylinder 106 and are positioned in such a manner that thepads spool 160 at diametrically opposite locations. It will be appreciated that this reduces the risk of shifting thespool 160 off the thread axis which might lock or, at the very least, unduly restrict extension and retraction of thetow bar 104. Threaded caps 176 and 178 are provided in therespective sleeves spring washers caps pads spool 160, while unscrewing of thecaps spool 160 by thepads caps tow bar 104 is consequently capable of absorbing relatively greater loads. On the other hand, unscrewing of thecaps tow bar 104 can only absorb relatively smaller loads. - The operation of the illustrated conveyor system should be apparent from the foregoing description. Thus, it shall be sufficient to explain that a load is supported on the table96 and moved along the conveyor path while the
stop mechanism 52 is in the engaged position. However, when themechanism 52 is swung to the disengaged position and held against further forward movement (which causes simultaneous sudden stopping of the accumulating trolley 38), the momentum of theload carriage 40 and the item(s) supported thereon is absorbed as thetow bar 104 retracts. None of the absorbed energy is stored, and thetow bar 104 consequently does not cause thecarrier 36 to lunge forwardly once the restraint against forward stop mechanism movement is removed. In addition, when thestop mechanism 52 is engaged by one of the pusher dogs 26, thetow bar 104 slowly extends and thecarriage 40 is gradually accelerated to the speed of the accumulatingtrolley 38. Ideally, thetow bar 104 will extend to the fully extended position shown in FIG. 4, such that the full stroke of thetow bar 104 will be available to absorb the energy generated the next time thecarrier 36 is suddenly stopped. - The preferred forms of the invention described above are to be used as illustration only, and should not be utilized in a limiting sense in interpreting the scope of the present invention. Obvious modifications to the exemplary embodiments, as hereinabove set forth, could be readily made by those skilled in the art without departing from the spirit of the present invention.
- The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set forth in the following claims.
Claims (100)
1. A cushioning device connectable between two relatively moveable structures to cushion movement between the structures, said device comprising:
first and second shiftably interconnected components,
said first component being connectable to one of the structures for movement therewith, and said second component being connectable to the other of the structures for movement therewith,
said components being threadably intercoupled so that relative shifting of the components requires a screwing or unscrewing action that serves to cushion movement between the structures.
2. A cushioning device as claimed in ,
claim 1
said components including respective elongated bodies that are telescopically intermitted, with relative shifting of the components being defined along a longitudinal axis that is cooperatively defined by the bodies.
3. A shock absorbing tow bar for interconnecting a drive unit and a load-supporting unit of a conveyor system, said tow bar comprising:
first and second components being interconnected so as to permit limited relative shifting therebetween,
said first component being connectable to the drive unit, and said second component being connectable to the load-supporting unit,
said components being threadably intercoupled so that relative shifting of the components requires a screwing or unscrewing action that serves to cushion movement between the units.
4. A shock absorbing tow bar as claimed in ,
claim 3
said components including respective elongated bodies that are telescopically interfitted, with relative shifting of the components being defined along a longitudinal axis that is cooperatively defined by the bodies.
5. A load carrier for a conveyor system, said carrier comprising:
a drive unit;
a load-supporting unit in trailing relationship with the drive unit; and
a shock absorbing tow bar for connecting the load-supporting unit to the drive unit, said tow bar including
first and second components being interconnected so as to permit limited relative shifting therebetween,
said first component being connectable to the drive unit, and said second component being connectable to the load-supporting unit,
said components being threadably intercoupled so that relative shifting of the components requires a screwing or unscrewing action that serves to cushion movement between the drive and load-supporting units.
6. A load carrier as claimed in ,
claim 5
said drive unit comprising an accumulating trolley,
said load-supporting unit comprising an intermediate trolley connected to the accumulating trolley by the tow bar, a trailing trolley spaced rearwardly from the intermediate trolley, and a support table supported between the intermediate and trailing trolleys.
7. A load carrier as claimed in ,
claim 5
said components including respective elongated bodies that are telescopically interfitted, with relative shifting of the components being defined along a longitudinal axis that is cooperatively defined by the bodies.
8. A shock absorbing device for cushioning relative movement between two structures, said device comprising:
a first component connectable to one of the structures;
a second component connectable to the other of the structures; and
a third component threadably engaging the first and second components so that relative shifting of the first and second components requires rotation of the third component.
9. A shock absorbing device as claimed in ,
claim 8
said first component and said second components being restrained from rotation relative to one another.
10. A shock absorbing device as claimed in ; and
claim 8
a brake mechanism for restraining rotation of the third component.
11. A shock absorbing device as claimed in ,
claim 8
said first and second components being at least partially externally threaded,
said third component being at least partially internally threaded.
12. A shock absorbing device as claimed in ,
claim 8
said third component having a first end threadably engaging the first component and a second end threadably engaging the second component,
said first end including a first intern ally threaded portion and said second end including a second internally threaded portion,
said first and second internally threaded portions being oppositely inclined.
13. A shock absorbing device as claimed in ,
claim 8
said third component being laterally shiftable relative to said first and second components.
14. A shock absorbing tow bar for interconnecting a drive unit and a load-supporting unit of a conveyor system, said tow bar comprising:
a first component connectable to one of the units;
a second component connectable to the other of the units; and
a third component threadably engaging the first and second components so that relative shifting of the first and second components requires rotation of the third component.
15. A tow bar as claimed in ,
claim 14
said first component and said second components being restrained from rotation relative to one another.
16. A tow bar as claimed in ; and
claim 14
a brake mechanism for restraining rotation of the third component.
17. A tow bar as claimed in ,
claim 14
said first and second components being at least partially externally threaded,
said third component being at least partially internally threaded.
18. A tow bar as claimed in ,
claim 14
said third component having a first end threadably engaging the first component and a second end threadably engaging the second component,
said first end including a first internally threaded portion and said second end including a second internally threaded portion,
said first and second internally threaded portions being oppositely inclined.
19. A tow bar as claimed in ,
claim 14
said third component being laterally shiftable relative to said first and second components.
20. A load carrier for a conveyor system, said load carrier comprising:
a drive unit;
a load-supporting unit in trailing relationship with the drive unit; and
a shock absorbing tow bar for connecting the load-supporting unit to the drive unit, said tow bar including
a first component connected to one of the units,
a second component connected to the other of the units; and
a third component threadably engaging the first and second components so that relative shifting of the first and second components requires rotation of the third component.
21. A load carrier as claimed in ,
claim 20
said first component and said second components being restrained from rotation relative to one another.
22. A load carrier as claimed in , and
claim 20
a brake mechanism for restraining rotation of the third component.
23. A load carrier as claimed in ,
claim 20
said first and second components being at least partially externally threaded,
said third component being at least partially internally threaded.
24. A load carrier as claimed in ,
claim 20
said third component having a first end threadably engaging the first component and a second end threadably engaging the second component,
said first end including a first internally threaded portion and said second end including a second internally threaded portion,
said first and second internally threaded portions being oppositely inclined.
25. A load carrier as claimed in ,
claim 20
said third component being laterally shiftable relative to said first and second components.
26. A shock absorbing device for cushioning relative movement of two structures, said shock absorbing device extending between the two structures in an impact direction, said device comprising:
a first component connectable to one of the structures;
a second component that translates in the impact direction when the two structures move relative to one another, said second component presenting a braking surface; and
a brake fixed relative to the first component and frictionally engaging the braking surface to thereby inhibit translation of the second component relative to the first component in the impact direction.
27. A shock absorbing device as claimed in ,
claim 26
said second component at least partially disposed in the first component.
28. A shock absorbing device as claimed in ,
claim 27
said brake at least partially disposed in the first component.
29. A shock absorbing device as claimed in ; and
claim 26
a third component shiftable relative to the first component in the impact direction,
said third component connectable to the other of the structures.
30. A shock absorbing device as claimed in ,
claim 29
said second component at least partially disposed in the first and third components.
31. A shock absorbing device as claimed in ,
claim 30
said second component coupled to the third component.
32. A shock absorbing device as claimed in ,
claim 30
said brake at least partially disposed in the first and third components.
33. A shock absorbing device as claimed in ,
claim 32
said third component defining an opening therein for accessing the brake.
34. A shock absorbing device as claimed in ,
claim 33
said brake being adjustable to vary the frictional force between the brake and the braking surface.
35. A shock absorbing tow bar for interconnecting a drive unit and a load-support unit of a conveyor system, said shock absorbing tow bar extending between the drive unit and the load-supporting unit in an impact direction, said tow bar comprising:
a first component connectable to one of the units;
a second component that translates in the impact direction when the two units move relative to one another, said second component presenting a braking surface; and
a brake fixed relative to the first component and frictionally engaging the braking surface to thereby inhibit translation of the second component relative to the first component in the impact direction.
36. A tow bar as claimed in ,
claim 35
said second component at least partially disposed in the first component.
37. A tow bar as claimed in ,
claim 36
said brake at least partially disposed in the first component.
38. A tow bar as claimed in ; and
claim 35
a third component shiftable relative to the first component in the impact direction,
said third component connectable to the other of the units.
39. A tow bar as claimed in ,
claim 38
said second component at least partially disposed in the first and third components.
40. A tow bar as claimed in ,
claim 39
said second component coupled to the third component.
41. A tow bar as claimed in ,
claim 39
said brake at least partially disposed in the first and third components.
42. A tow bar as claimed in ,
claim 41
said third component defining an opening therein for accessing the brake.
43. A tow bar as claimed in ,
claim 42
said brake being adjustable to vary the frictional force between the brake and the braking surface.
44. A load carrier for a conveyor system, said load carrier comprising:
a drive unit;
a load-supporting unit in trailing relationship with the drive unit; and
a shock absorbing tow bar for connecting the load-supporting unit to the drive unit, said shock absorbing tow bar extending between the load-supporting unit and the drive unit in an impact direction, said tow bar including
a first component connected to one of the units;
a second component that translates in the impact direction when the two units move relative to one another, said second component presenting a braking surface; and
a brake fixed relative to the first component and frictionally engaging the braking surface to thereby inhibit translation of the second component relative to the first component in the impact direction.
45. A load carrier as claimed in ,
claim 44
said second component at least partially disposed in the first component.
46. A load carrier as claimed in ,
claim 45
said brake at least partially disposed in the first component.
47. A load carrier as claimed in ; and
claim 44
a third component shiftable relative to the first component in the impact direction,
said third component connected to the other of the units.
48. A load carrier as claimed in ,
claim 47
said second component at least partially disposed in the first and third components.
49. A load carrier as claimed in ,
claim 48
said second component coupled to the third component.
50. A load carrier as claimed in ,
claim 48
said brake at least partially disposed in the first and third components.
51. A load carrier as claimed in ,
claim 50
said third component defining an opening therein for accessing the brake.
52. A load carrier as claimed in ,
claim 51
said brake being adjustable to vary the frictional force between the brake and the braking surface.
53. A shock absorbing device for cushioning relative movement between two structures, said device comprising:
a first component connectable to one of the structures;
a second component that moves relative to the first component when the two structures move relative to one another, said second component presenting a braking surface; and
a brake fixed to the first component and frictionally engaging the braking surface,
said brake being adjustable so that the magnitude of the frictional engagement force between the brake and the braking surface can be varied.
54. A shock absorbing device as claimed in ,
claim 53
said brake including a sleeve coupled to the first component and a cap threadably engaging the sleeve so that rotation of the cap relative to the sleeve causes translation of the cap relative to the sleeve.
55. A shock absorbing device as claimed in ,
claim 54
said brake including a brake pad at least partially disposed within the sleeve for frictionally engaging the braking surface.
56. A shock absorbing device as claimed in ,
claim 55
said brake including a cushioning element interposed between the cap and the brake pad.
57. A shock absorbing device as claimed in ,
claim 56
said cushioning element being a spring washer.
58. A shock absorbing device as claimed in ,
claim 53
said second component at least partially disposed within the first component.
59. A shock absorbing device as claimed in ; and
claim 58
said third component connectable to the other of the structures and shiftably coupled to the first component.
60. A shock absorbing device as claimed in ,
claim 59
said second component and said brake at least partially disposed in the third component.
61. A shock absorbing device as claimed in ,
claim 60
said third component defining an opening therein for accessing the brake.
62. A shock absorbing device for interconnecting a drive unit and a load-supporting unit of a conveyor system, said tow bar comprising:
a first component connectable to one of the units;
a second component that moves relative to the first component when the two units move relative to one another, said second component presenting a braking surface; and
a brake fixed relative to the first component and frictionally engaging the braking surface,
said brake being adjustable so that the magnitude of the frictional engagement force between the brake and the braking surface can be varied.
63. A tow bar as claimed in ,
claim 62
said brake including a sleeve coupled to the first component and a cap threadably engaging the sleeve so that rotation of the cap relative to the sleeve causes translation of the cap relative to the sleeve.
64. A tow bar as claimed in ,
claim 63
said brake including a brake pad at least partially disposed within the sleeve for frictionally engaging the braking surface.
65. A tow bar as claimed in ,
claim 64
said brake including a cushioning element interposed between the cap and the brake pad.
66. A tow bar as claimed in ,
claim 65
said cushioning element being a spring washer.
67. A tow bar as claimed in ,
claim 62
said second component at least partially disposed within the first component.
68. A tow bar as claimed in ; and
claim 67
said third component connectable to the other of the units and shiftably coupled to the first component.
69. A tow bar as claimed in ,
claim 68
said second component and said brake at least partially disposed in the third component.
70. A tow bar as claimed in ,
claim 69
said third component defining an opening therein for accessing the brake.
71. A load carrier for a conveyor system, said load carrier comprising:
a drive unit;
a load-supporting unit in trailing relationship with the drive unit; and
a shock absorbing tow bar for connecting the load-supporting unit to the drive unit, said tow bar including
a first component connected to one of the units;
a second component that moves relative to the first component when the two units move relative to one another, said second component presenting a braking surface; and
a brake fixed relative to the first component and frictionally engaging the braking surface,
said brake being adjustable so that the magnitude of the frictional engagement force between the brake and the braking surface can be varied.
72. A load carrier as claimed in ,
claim 71
said brake including a sleeve coupled to the first component and a cap threadably engaging the sleeve so that rotation of the cap relative to the sleeve causes translation of the cap relative to the sleeve.
73. A load carrier as claimed in ,
claim 72
said brake including a brake pad at least partially disposed within the sleeve for frictionally engaging the braking surface.
74. A load carrier as claimed in ,
claim 73
said brake including a cushioning element interposed between the cap and the brake pad.
75. A load carrier as claimed in ,
claim 74
said cushioning element being a spring washer.
76. A load carrier as claimed in ,
claim 71
said second component at least partially disposed within the first component.
77. A load carrier as claimed in ; and
claim 76
said third component connected to the other of the units and shiftably coupled to the first component.
78. A load carrier as claimed in ,
claim 77
said second component and said brake at least partially disposed in the third component.
79. A load carrier as claimed in ,
claim 78
said third component defining an opening therein for accessing the brake.
80. A shock absorbing device for cushioning relative movement between two structures, said device comprising:
a first component connectable to one of the structures and presenting a first sleeve;
a second component connectable to the other of the structures and presenting a second sleeve,
said first and second sleeves being telescopically interfitted;
a third component presenting a braking surface which shifts relative to the first component when the first and second components are shifted relative to one another; and
a brake coupled to the first component and frictionally engaging the braking surface to thereby inhibit shifting of the third component relative to the first component.
81. A shock absorbing device as claimed in ,
claim 80
said first sleeve being telescopically received in the second sleeve.
82. A shock absorbing device as claimed in ,
claim 81
said third component at least partially disposed in the first and second sleeves.
83. A shock absorbing device as claimed in ,
claim 82
said third component being coupled to the second component.
84. A shock absorbing device as claimed in ,
claim 83
said brake being fixedly coupled to the first sleeve.
85. A shock absorbing device as claimed in ,
claim 84
said second sleeve defining an opening therein for accessing the brake.
86. A shock absorbing device as claimed in ,
claim 85
said brake being adjustable to vary the frictional force between the brake and the braking surface.
87. A shock absorbing tow bar for interconnecting a drive unit and a load-supporting unit of a conveyor system, said tow bar comprising:
a first component connectable to one of the units and presenting a first sleeve;
a second component connectable to the other of the units and presenting a second sleeve,
said first and second sleeves being telescopically interfitted;
a third component presenting a braking surface which shifts relative to the first component when the first and second components are shifted relative to one another; and
a brake coupled to the first component and frictionally engaging the braking surface to thereby inhibit shifting of the third component relative to the first component.
88. A tow bar as claimed in ,
claim 87
said first sleeve being telescopically received in the second sleeve.
89. A tow bar as claimed in ,
claim 88
said third component at least partially disposed in the first and second sleeves.
90. A tow bar as claimed in ,
claim 89
said third component being coupled to the second component.
91. A tow bar as claimed in ,
claim 90
said brake being fixedly coupled to the first sleeve.
92. A tow bar as claimed in ,
claim 91
said second sleeve defining an opening therein for accessing the brake.
93. A tow bar as claimed in ,
claim 92
said brake being adjustable to vary the frictional force between the brake and the braking surface.
94. A load carrier for a conveyor system, said load carrier comprising:
a drive unit;
a load-supporting unit in trailing relationship with the drive unit; and
a shock absorbing tow bar for connecting the load-supporting unit to the drive unit, said tow bar including
a first component connected to one of the units and presenting a first sleeve;
a second component connected to the other of the units and presenting a second sleeve,
said first and second sleeves being telescopically interfitted;
a third component presenting a braking surface which shifts relative to the first component when the first and second components are shifted relative to one another; and
a brake coupled to the first component and frictionally engaging the braking surface to thereby inhibit shifting of the third component relative to the first component.
95. A load carrier as claimed in ,
claim 94
said first sleeve being telescopically received in a second sleeve.
96. A load carrier as claimed in ,
claim 95
a third component at least partially disposed in the first and second sleeves.
97. A load carrier as claimed in ,
claim 96
said third component being coupled to the second component.
98. A load carrier as claimed in ,
claim 97
said brake being fixedly coupled to the first sleeve.
99. A load carrier as claimed in ,
claim 98
said second sleeve defining an opening therein for accessing the brake.
100. A load carrier as claimed in ,
claim 99
said brake being adjustable to vary the frictional force between the brake and the braking surface.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/832,400 US6330953B2 (en) | 1999-09-24 | 2001-04-11 | Shock absorbing tow bar for trolley-type conveyor systems |
US09/681,976 US6330952B2 (en) | 1999-09-24 | 2001-07-02 | Shock absorbing tow bar for trolley-type conveyor systems |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/404,899 US6244451B1 (en) | 1999-09-24 | 1999-09-24 | Shock absorbing tow bar for trolley-type conveyor systems |
US09/832,400 US6330953B2 (en) | 1999-09-24 | 2001-04-11 | Shock absorbing tow bar for trolley-type conveyor systems |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/404,899 Continuation US6244451B1 (en) | 1999-09-24 | 1999-09-24 | Shock absorbing tow bar for trolley-type conveyor systems |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/681,976 Division US6330952B2 (en) | 1999-09-24 | 2001-07-02 | Shock absorbing tow bar for trolley-type conveyor systems |
Publications (2)
Publication Number | Publication Date |
---|---|
US20010011648A1 true US20010011648A1 (en) | 2001-08-09 |
US6330953B2 US6330953B2 (en) | 2001-12-18 |
Family
ID=23601498
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/404,899 Expired - Fee Related US6244451B1 (en) | 1999-09-24 | 1999-09-24 | Shock absorbing tow bar for trolley-type conveyor systems |
US09/832,400 Expired - Fee Related US6330953B2 (en) | 1999-09-24 | 2001-04-11 | Shock absorbing tow bar for trolley-type conveyor systems |
US09/681,976 Expired - Fee Related US6330952B2 (en) | 1999-09-24 | 2001-07-02 | Shock absorbing tow bar for trolley-type conveyor systems |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/404,899 Expired - Fee Related US6244451B1 (en) | 1999-09-24 | 1999-09-24 | Shock absorbing tow bar for trolley-type conveyor systems |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/681,976 Expired - Fee Related US6330952B2 (en) | 1999-09-24 | 2001-07-02 | Shock absorbing tow bar for trolley-type conveyor systems |
Country Status (4)
Country | Link |
---|---|
US (3) | US6244451B1 (en) |
AU (1) | AU7117800A (en) |
CA (1) | CA2319301A1 (en) |
WO (1) | WO2001023235A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050009521A1 (en) * | 2003-07-10 | 2005-01-13 | Preece Scott E. | Obtaining service when in a no-coverage area of a communication system |
CN107337003A (en) * | 2016-05-02 | 2017-11-10 | 海运快速有限责任公司 | Method and apparatus for intermodal container handling |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19826863B4 (en) * | 1998-06-17 | 2004-11-25 | Robert Bosch Gmbh | Workpiece carrier |
US6244451B1 (en) * | 1999-09-24 | 2001-06-12 | Conveyor Technology Group, Inc. | Shock absorbing tow bar for trolley-type conveyor systems |
US6679185B2 (en) * | 2002-02-27 | 2004-01-20 | Automatic Systems, Inc. | Adjustable shock absorbing tow bar |
US6845720B2 (en) * | 2003-04-09 | 2005-01-25 | Gareth D. Summa | Conveyor shock absorber |
CA2465474C (en) * | 2003-05-01 | 2012-07-10 | Daifuku Co., Ltd. | Conveyance apparatus using movable bodies |
US7600617B1 (en) * | 2005-03-28 | 2009-10-13 | General Manufacturing Systems, Inc. | Industrial shock absorber for use in a conveyor system |
WO2012018925A1 (en) * | 2010-08-04 | 2012-02-09 | Illinois Tool Works Inc. | Load-independent motion control system |
DE102011100825B4 (en) * | 2011-05-07 | 2022-12-15 | Eisenmann Gmbh | Spindle conveyor and system for treating workpieces with such |
US10053306B2 (en) | 2016-05-02 | 2018-08-21 | Sea-Train Express—Llc | Apparatus and method for intermodal container handling |
US9637327B1 (en) | 2016-05-02 | 2017-05-02 | Sea-Train Express—Llc | Method and apparatus for intermodal container handling |
Family Cites Families (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1309490A (en) * | 1919-07-08 | stanley | ||
US1089830A (en) * | 1913-11-14 | 1914-03-10 | Willy R Frommater | Shock-absorber. |
US1761272A (en) * | 1926-07-29 | 1930-06-03 | Miner Inc W H | Shock absorber |
US1894717A (en) * | 1931-07-06 | 1933-01-17 | Cardwell Westinghouse Co | Cushioning device |
US2856179A (en) * | 1954-11-22 | 1958-10-14 | Cleveland Pneumatic Ind Inc | Shock absorber |
US3059727A (en) * | 1960-12-08 | 1962-10-23 | Airborne Accessories Corp | Energy absorption device |
US3796288A (en) * | 1972-10-10 | 1974-03-12 | H Hollnagel | One or two way energy (shock) absorber |
US4619575A (en) | 1985-01-28 | 1986-10-28 | Mid-West Conveyor Company, Inc. | Apparatus for storage and retrieval of thin trays and sheets |
US4790247A (en) | 1986-11-04 | 1988-12-13 | Midwest Conveyor Company, Inc. | Trolley stop for power and free conveyors |
US5033394A (en) | 1989-10-06 | 1991-07-23 | Mid-West Conveyor Company, Inc. | Floor conveyor junction seal gap closure |
US5067414A (en) | 1990-02-12 | 1991-11-26 | Mid-West Conveyor Company, Inc. | Self-adjusting shock absorbing carrier |
US5303655A (en) | 1992-09-28 | 1994-04-19 | Mid-West Conveyor Company, Inc. | Automatic stabilizer unit for free trolley having vertically movable wheels resonsive to trackside rails |
US5511486A (en) | 1994-09-16 | 1996-04-30 | Lico, Inc. | Shock absorbing tow bar |
US5632206A (en) | 1995-07-14 | 1997-05-27 | Mid-West Conveyor Company, Inc. | Adjustable cushioned tow bar for power and free conveyor |
US6244451B1 (en) * | 1999-09-24 | 2001-06-12 | Conveyor Technology Group, Inc. | Shock absorbing tow bar for trolley-type conveyor systems |
-
1999
- 1999-09-24 US US09/404,899 patent/US6244451B1/en not_active Expired - Fee Related
-
2000
- 2000-09-05 AU AU71178/00A patent/AU7117800A/en not_active Abandoned
- 2000-09-05 WO PCT/US2000/024455 patent/WO2001023235A1/en active Application Filing
- 2000-09-14 CA CA002319301A patent/CA2319301A1/en not_active Abandoned
-
2001
- 2001-04-11 US US09/832,400 patent/US6330953B2/en not_active Expired - Fee Related
- 2001-07-02 US US09/681,976 patent/US6330952B2/en not_active Expired - Fee Related
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050009521A1 (en) * | 2003-07-10 | 2005-01-13 | Preece Scott E. | Obtaining service when in a no-coverage area of a communication system |
CN107337003A (en) * | 2016-05-02 | 2017-11-10 | 海运快速有限责任公司 | Method and apparatus for intermodal container handling |
Also Published As
Publication number | Publication date |
---|---|
US6330953B2 (en) | 2001-12-18 |
WO2001023235A9 (en) | 2002-11-07 |
CA2319301A1 (en) | 2001-03-24 |
US6330952B2 (en) | 2001-12-18 |
US6244451B1 (en) | 2001-06-12 |
WO2001023235A1 (en) | 2001-04-05 |
AU7117800A (en) | 2001-04-30 |
US20010030162A1 (en) | 2001-10-18 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6330952B2 (en) | Shock absorbing tow bar for trolley-type conveyor systems | |
US5094424A (en) | Bicycle seat post shock absorber assembly | |
FI88376C (en) | Resilient and pivotable guide roller | |
US4978133A (en) | Trailer hitch shock absorber | |
CA2151314C (en) | Unloading device | |
US4000912A (en) | Shock absorber | |
CN102630205A (en) | Steering column for a motor vehicle | |
US6406092B1 (en) | Car seat | |
US6679185B2 (en) | Adjustable shock absorbing tow bar | |
US5632206A (en) | Adjustable cushioned tow bar for power and free conveyor | |
SE9904397L (en) | DISC BRAKE | |
US5511486A (en) | Shock absorbing tow bar | |
CN102317086A (en) | Wheel suspension | |
US5027715A (en) | Shock absorbing carrier | |
US5067414A (en) | Self-adjusting shock absorbing carrier | |
US3005640A (en) | Dolly | |
US3742774A (en) | Adjustable stroke retractor mechanism | |
US3766800A (en) | Variable efficiency mechanical transmission | |
US6523671B2 (en) | Conveyor escapement | |
US3561578A (en) | Decelerating device | |
CN210682185U (en) | Ground rail car with stabilising arrangement | |
CN210502930U (en) | Shock-absorbing walking mechanism of fire-fighting robot | |
CN107985449B (en) | Transport trailer | |
US4785711A (en) | Weapon mount useful for combat vehicle | |
US4819540A (en) | Weapon mount useful for combat vehicle |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
REMI | Maintenance fee reminder mailed | ||
LAPS | Lapse for failure to pay maintenance fees | ||
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20051218 |