US3854414A

US3854414A - Power merge-synchronous

Info

Publication number: US3854414A
Application number: US00417322A
Authority: US
Inventors: B Bradbury
Original assignee: Rexnord Inc
Current assignee: FKI Industries Inc
Priority date: 1973-11-19
Filing date: 1973-11-19
Publication date: 1974-12-17
Anticipated expiration: 1991-12-17

Abstract

In a unit carrier system in which a plurality of cars are driven over a trackway, a merge assisting device for interleaving on an outgoing track cars approaching a merge on a plurality of different incoming tracks. In its preferred form, this device comprises chain-mounted dogs which cooperate with cams mounted on the sides of the cars to accelerate the cars from their incoming speeds to outgoing speeds sufficiently greater than their incoming speeds so that the cars may be interleaved at the merge without danger of collision.

Description

1 Dec. 17, 1974 United States Patent 1 Bradbury POWER MERGE-SYNCHRONOUS Primary Examiner-M. Henson Wood, Jr.

Assistant Examiner-Richard A. Bertsch 1 B G. B db Ch' C l'f. [75] Inventor emard m my 100 an Attorney, Agent, or F1rn1Sughrue, Rothwell, Mum,

Zinn & Macpeak [73] Assignee: Rexnord Inc., Milwaukee, Wis.

Nov. 19, 1973 [22] Filed:

[57] ABSTRACT In a unit carrier system in which a plurality of cars are driven over a trackway, a merge assisting device for interleaving on an outgoing track cars approaching a merge on a plurality of different incoming tracks. in its preferred form, this device comprises chain- Appl. No.: 417,322

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mounted dogs which cooperate with cams mounted on the sides of the cars to accelerate the cars from their incoming speeds to outgoing speeds sufficiently greater than their incoming speeds so that the cars S T N m m mm QT mA me e D E n N U m 5 104/172 R may be interleaved at the merge without danger of 104/96 collision. 104/130 3,044,415 7/1962 3 196 804 7/1965 Harrison 3,477,388 11/1969 Klamp 45 Claims, 9 Drawing Figures PATENTED HEB] H914 SHEET 2 BF 2 POWER MERGE-SYNCHRONOUS FIELD OF THE INVENTION This invention relates generally to power merges in a unit carrier system and, more specifically, to power merges suitable for use with a unit carrier system such as is disclosed in commonly assigned U.S. Pats. Nos. 3,621,790, 3,626,859, and 3,650,216.

BACKGROUND OF THE INVENTION Commonly assigned U.S. Pat. No. 3,626,859 discloses an idle-car storage and dispensing system which may also be used as a merging system, the cars on the subsidiary of two merging lines being handled in the same way as the sidelined, idle cars are in that patent. In such a system, a car on the subsidiary line may be stopped just short of the merge by a dynamic stop such as is disclosed in commonly assigned U.S. application Ser. No. 309,026, filed Nov. 24, 1972, and later abandoned in favor of continuation application Ser. No. 463,716, filed Apr. 24, 1974, if appropriate photocells or other sensors such as are disclosed in U.S. Pat. No. 3,626,859 detect an impending collision if the car is allowed to proceed immediately on to the main line. Once the car is stopped, it remains in the stopped position until a clear window is sensed on the main line. When such a window is sensed, the dynamic stop is retracted, and the friction-powered car drive then propels the car out on to the main line, where it gradually attains the same velocity as the other cars already on that line. All this is explained more fully in U.S. Pat. No. 3,626,859, and the apparatus disclosed therein is satisfactory for many situations.

However, the accelerational ability of many unit carriers is inherently rather limited, and configurations such as that disclosed in U.S. Pat. No. 3,626,859 accordingly requires a rather long clear window in the stream of traffic on the main line in order to allow the stopped car on the subsidiary line to move out on to the main line without danger of a rear-end collision. If the main line is heavily trafficked, this requirement can easily result in a highly undesirable backup of the cars on the subsidiary line.

As a solution to this problem, I developed the accelerator merge disclosed in commonly assigned U.S. patent application Ser. No. 315,059, filed Dec. I4, 1972. In the preferred embodiment of this device, the clear window required in the stream of traffic on the main line in order to allow a stopped car on the subsidiary line to move out on to the main line without danger of a rear-end collision is considerably shortened. This is accomplished by assisting the acceleration of the car with an external power source which acts on a cam mounted on the side of the car. The cam is engaged by a dog mounted on a chain which parallels the fixed path of the car so that the dog remains in engagement with the cam for a considerable portion of the time it is accelerating. The chain is, in turn. powered by any appropriate means, as, for instance, a hydraulic motor.

However, this device is most suitable for use in a system where the cars are brought to a complete stop on the subsidiary line before long accelerated out on to the main line, and it still requires that a clear window be found in the stream of traffic on the main line, which requirement can still result in an undesirable backup of the cars on the subsidiary line if the main line is heavily enough trafficked.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a merge having two incoming lines and employing an embodiment of the present invention. Some superstructure shown in the other figures is omitted for the sake of clarity.

FIG. 2 is a view taken along the lines 22 in FIG. 1,

but omitting some background detail.

FIG. 3 is a view taken along the lines 33 in FIG. 1.

FIG. 4 is a view taken along the lines 44 in FIG. 1, but omitting the background.

FIG. 5 is a greatly enlarged view of a detail of FIG. 1.

FIG. 6 is a side view of the plan view shown in FIG. 5, but omitting the sprocket.

FIG. 7. is a view taken along the lines 77 in FIG. 6.

FIG. 8 is a view taken along the lines 88 in FIG. 6, showing a cam engaged by a dog.

FIG. 9 is a view taken in the same place as FIG. 8, but showing the cam forcing the dog out of the way.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT To illustrate the present invention, a merge having two incoming lines will be described in detail. It will be understood, however, that the principal of the present invention is equally applicable to merges having more than two incoming lines.

FIG. 1 shows a merge of a line 10 with a line 12 in the trackway of a track-guided unit carrier system. As shown by the arrows, the cars 14 on both lines move from left to right. The cars 14 have two cam followers 16, one mounted on either side thereof. The cam followers 16 may be used in unloading the cars 14 while in motion in the manner set forth in commonly assigned U.S. Pat. No. 3,613,916, and they may also be used to accelerate the cars 14 from the velocities at which they approach the merge to a velocity permitting them to be interleaved at the merge without danger of collision. As will be obvious from what follows, means must be provided for driving the cars 14 on the outgoing track at the speed to which they are brought by the merge device described and claimed herein, but. as these means form no part of the present invention, they will not be described herein.

Mounted adjacent to each of the incoming tracks are controlled-pathway, propelling devices, designated generally by the numeral 18, each of which comprises two

parallel chains

20, 22 and a plurality of double sprockets 24. Each of the pairs of

parallel chains

20, 22

carries between the two chains a plurality of dogs 26 (shown in detail in FIGS. -9) and a plurality of supporting plates 28 which are carried by the

chains

20, 22 at much closer intervals than the dogs 26 and serve to support the upper chain 20. The plates 28 must either (I) be constructed of sufficiently flexible material to permit them to flex as they are passed around the double sprockets 24, (2) be mounted on the

chains

20, 22 with provisions for lost motion in the mounting permitting them to turn the corners without bending, or (3) be connected to one link only on each

chain

20, 22.

The controlled-pathway, propelling devices 18 are positioned so that the dogs 26 which they carry will engage the upstream side of the cam followers 16 on the adjacent side of the cars 14 as they approach the merge and remain in engagement with them until the cars have at least reached the merge. The dogs 26 are preferably constructed in the manner shown in FIGS. 5-9 in order (I) to absorb some of the shock of impact when the dog 26 comes into contact with a cam follower 16 and (2) to permit the operative portion of the dog 26 to pivot out of the way in the event that the dog and a cam follower reach the same point at the same time. As shown, the preferred embodiment of the dog 26 comprises an engaging block 50, two pivotable pull arms 52, two pull sleeves 54, and four compression springs 56 mounted on two U-bolts 58, the former serving to bias the pull arms 52 against the pull sleeve 54. As best seen in FIGS. 6 and 8, the engaging block 50 is positioned to bear against the upstream surface of the cam follower 16 when the dog 26 overtakes the cam follower 16 in the ordinary course of events. Since the dog 26 would then be moving much faster than the cam follower 16, the overtaking of the cam follower 16 by the dog 26 causes a considerable impact, part of the force of which is taken up by the compression of the compression springs 56 between inner spring seats in the pull sleeves 54 and the upstream surfaces of the saddles 60. During this process, the pull arms 52 separate from the pull sleeves 54 and the saddles 60 slide along the links of the

chains

20, 22. The springs 56 are mounted on the U-bolts 58 which wrap around mating surfaces of the pull arms 52, transmitting the impact from the cam follower 16 through the dogs 26 to the

chains

20, 22.

To permit the engaging block 50 to pivot out of the way in case it and a cam follower 16 reach the same point at the same time, the pull arms 52 are adapted to pivot in the bases of the U-bolts 58. As may best be understood by comparing FIGS. 8 and 9, the compression springs 56 normally pull the flat, downstream surfaces of the pull arms 52 against the flat, upstream surfaces of the pull sleeves 54, as depicted in FIG. 8, but if the engaging block 50 and the cam follower 16 begin to bind laterally, the cam follower forces the pull arms 52 to pivot around their outboard, downstream corners, permitting the dog 26 to pass by the cam follower 16 without engaging it. In that event, the car 14 is picked up by the next dog 26, and the controlled-pathway,-

propelling devices 18 must accordingly be long enough so that a car 14 can just miss one dog 26 in this fashion, and yet be picked up and accelerated by the next succeeding dog 26 before it reaches the merge.

The controlled-pathway, propelling devices 18 are driven by motor 30 at a speed at least equal to the fastest speed at which the cars 14 enter the merge times the number of incoming tracks. In the simplest case, where there are only two incoming tracks and all cars on both incoming tracks are moving at the same speed, the controlled-pathway, propelling devices 18 are driven at a speed of at least twice that of the incoming cars.

The motor 30 drives a chain 32 which in turn drives both pairs of

parallel chains

20, 22, as seen in the upper right-hand of FIG. 1 and in FIG. 2. The chain 32 also serves the essential function of synchronizing the two controlled-pathway, propelling devices 18 so that the cars 14 approaching the merge on the tracks 10 and 12 reach it alternately and at intervals permitting them to interleave without colliding with one another. In general, this is accomplished by spacing the dogs so that the last car 14 reaching the merge on one incoming track before a car 14 reaches the merge on another incoming track is followed by an interval slightly in excess of the length of the longest car 14. The requirement that the interval be slightly in excess of the length of the longest car comes from the fact that the cars on different tracks are non-parallel as they merge, presenting to one another, not their length from front to back, but a length depending on the abruptness of the merge but approximating the distance from one front comer to the opposite rear corner.

Of course, the chain 32 and the dogs 26 must also be arranged so that the cars from the various incoming tracks reach the merge alternately. The alternation may be one-to-one or it may be at any integral ratio. The former type of alteration is useful where the incoming trackways are approximately equally heavily trafficked by cars moving at approximately the same speed, and the more general type of alternation is useful where certain of the trackways are consistently more heavily trafficked than others and/or the speed of the incoming cars on certain of the trackways is consistently greater than the speed on others.

In the embodiment shown in the drawing, a plurality of dogs 26 are carried by each controlled-pathway, propelling device 18, the dogs 26 being driven continuously in one direction and being spaced by a distance slightly in excess of twice the length of the longest of the cars 14 so as to leave a gap between two successive cars on one line sufficient for a car from the other line. In this embodiment, the distance upstream of the merge to which the controlled-pathway, propelling device 18 extends need only be sufficient so that an incoming car approaching the device just after a dog 26 carried by the device 18 has passed will be brought into synchronization by the following dog before the car has reached the merge.

Alternatively, the controlled-pathway, propelling devices 28 can carry a single dog 26, in which case the distance upstream of the merge to which the device must extend has to be sufficient so that an incoming care approaching the device just after the dog has passed will be brought into synchronization by the dog on its next pass before the car has reached the merge. This type of construction, more fully described in my copending, commonly assigned application Ser. No. 315,059, filed Dec. 14, 1972, and later abandoned in favor of continuation application Ser. No. 463,716, filed Apr. 24, 1974 is most useful when a linear reciprocating device, such as a hydraulic cylinder, is used instead of the device shown. Such a device may be used either directly or in connection with a chain and sprocket assembly which is driven first in one direction, then in the other, so as to recock the dog for successive cars. In either case, it is necessary to mount the dog 26 ratchet fashion, so that it will not engage the cam fol lower 16 while being recocked, but will do so on its driving stroke.

To give the

chains

20, 22 the strength required to transmit the power needed to accelerate the cars 14 by the required amount within a reasonable distance, it is necessary that they be quite heavy if the cars have appreciable mass, as they do in the uses contemplated by my assignee. In order to support and guide the

chains

20, 22, I accordingly use a quite elaborate structure illustrated in FIGS. 3 and 4. As may be seen therein, the

chains

20, 22 are connected by the previously mentioned plates 28, which are spaced at frequent intervals. The plates 28 support the upper chain 20 on the lower chain 22. At least while on the part of its path nearer to the cars, and, if the chain is heavy enough, during part or all of the rest of its path as well, the lower chain 22 is in turn supported on the horizontal wear strip 31 mounted on the structural member 32. The rollers of the

chains

20, 22 are also guided laterally during at least the time during which they are adjacent to the cars by lateral wear strips 34, 36, which are mounted on

structural members

32 and 38, respectively.

Since the dogs 26 travel at a much greater speed than the cars 14 as they enter the device, some means for ab sorbing the impact of the one on the other is required. The previously described compression springs 56 perform part of this function. However, in practice it has been found desirable to provide additional impactabsorbing means as well. Such means could take various forms as, for instance, a spring mounting of the cam followers 16 on the sides of the cars 14. However, I have devised a particularly satisfactory way of absorbing the impact and allowing acceleration to be transferred to the cars relatively gradually in which the absorbing means are a part of the drive means for the controlled-pathway, propelling device rather than on the cars themselves. As shown in FIG. 2, the double drive sprockets 24a are mounted on torsional springs 40 which normally transmit torque to the double sprockets 24a in the manner of a cylindrical shaft, but which absorb the impact of the cars 14 on the dogs 26 by uncurling slightly. In order to handle bumper-to-bumper traftic, the torsional springs 40 must be strong enough so that the impact of successive cars can be absorbed while a dog 26 is still in contact with and driving a previous car 14. In order to improve the resistance of the torsional springs 40 to axial flexing (i.e., bending of the axis), they may be mounted on shafts (not shown) such that the inner peripheries of the springs slide against the outer peripheries of the shafts as the springs curl and uncurl. If this expedient is used, however, it must be remembered that the torque from the motor 30 is transmitted through the torsional springs and not through the shafts.

Caveat While the present invention has been illustrated by a detailed description of a preferred embodiment thereof, it will be obvious to those skilled in the art that various changes in form and detail can be made therein without departing from the true scope of the invention. For instance, the two parallel accelerator chains are not a necessary feature of the present invention. While it has been found that carrying the dogs between two parallel chains gives added strength and stability tothe system, obviously the dogs could be carried on a single chain, particularly where the car and its contents were not heavy. Similarly, the dogs would not have to be carried on a chain or chains at all, but could be carried by any suitable controlled-pathway, propelling device, and the cam followers which engage the dogs need not be mounted on the sides of the car. They can as well be mounted on the top or bottom thereof, provided that the pathway of the dog is designed accordingly, or they could be dispensed with altogether and the dogs could engage some appropriate part of the cars themselves as, for instance, the rear end. Likewise, the synchronization of the controlled-pathway, propelling devices could be accomplished by electronic or any other appropriate means, rather than by means such as chain 32. Thus, my invention must be measured by the claims appended hereto and not by the foregoing preferred embodiment.

What is claimed is:

1. In a unit carrier system in which a plurality of cars are driven over a trackway having merges therein, a merge assisting device for interleaving on an outgoing track cars approaching a merge on a plurality of different incoming tracks without stopping said cars prior to the merge, said merge assisting device comprising:

a controlled-pathway, propelling device mounted adjacent to each of said incoming tracks; at least one dog carried by each of said controlledpathway, propelling devices and positioned to engage an incoming car on the adjacent one of said incoming tracks and to remain in engagement with said car until it has reached an exit speed at least equal to the speed of the fastest of said incoming cars times the number of said incoming tracks;

means for driving said controlled-pathway, propelling devices at said exit speed; and

means for synchronizing said controlled-pathway,

propelling devices so that said cars reach said merge at intervals at least slightly in excess of the length of the longest of said cars, whereby said cars may be interleaved on said outgoing track without danger of collision with one another.

2. A merge assisting device as claimed in claim 1 wherein at least one of said controlled-pathway, propelling devices comprises:

a chain and a plurality of sprockets for guiding said chain and imparting motion thereto.

3. A merge assisting device as claimed in claim 2 wherein said sprockets are driven in only one direction.

4. A merge assisting device as claimed in claim 2 wherein said sprockets are driven first in one direction, then in the other, whereby said dog is recocked for successive cars.

5. A merge assisting device as claimed in claim 2 wherein said dog is carried between two parallel chains.

6. A merge assisting device as claimed in claim 5 wherein said controlled-pathway, propelling device further comprises guide means for supporting said parallel chains and preventing deviation thereof from their prescribed pathway during that portion of their prescribed pathway during which said dog is in position to engage said cars.

7. A merge assisting device as claimed in claim 2 wherein said means for driving said controlledpathway, propelling device includes torsional springs which normally transmit torque to said sprockets in the manner of a cylindrical shaft, but which absorb the impact of said cars on said dog by curling or uncurling slightly.

8. A merge assisting device as claimed in claim I and further comprising means for absorbing the impact of said cars on said dogs.

9. A merge assisting device as claimed in claim 1 wherein said controlled-pathway, propelling device extends from upstream of said merge at least to said merge.

10. A merge assisting device as claimed in claim I wherein said dog comprises:

1. a pull sleeve mounted on said controlled-pathway,

propelling device;

2. an engaging block positioned to engage an incoming car on the adjacent one of said incoming tracks; and

3. yielding means connecting said pull sleeve to said engaging block, whereby said yielding means absorbs at least a part of the impact of said cars on said engaging block.

11. A merge assisting device as claimed in claim 10 wherein said yielding means comprises a spring.

12. A merge assisting device as claimed in claim 10 wherein said yielding means comprises:

1. a bolt connected to said engaging block and slidable in said pull sleeve;

2. a spring co-axially disposed about said bolt; and

3. butting means mounted on said bolt at an end thereof remote from said pull sleeve, said butting means operating to trap said spring between said pull sleeve and said butting means, whereby said spring absorbs at least a part of the impact of said cars on said engaging block.

13. A merge assisting device as claimed in claim 10 wherein said engaging block is pivotably mounted on said yielding means, said engaging block being pivotable from a position in which it can engage an incoming car on the adjacent one of said incoming tracks to a position in which said engaging block cannot engage incoming cars on the adjacent one of said incoming tracks.

14. A merge assisting device as claimed in claim 1 wherein said dog is pivotably mounted on said controlled-pathway, propelling device, said dog being pivotable from a position in which it can engage an incoming car on the adjacent one of said incoming tracks to a position in which said engaging block cannot engage incoming cars on the adjacent one of said incoming tracks.

15. A dog adapted to be mounted on a controlledpathway, propelling device and to impart momentum to objects moving on a controlled path adjacent to said controlled-pathway, propelling device, said dog comprising:

l. a pull sleeve mounted on said controlled-pathway,

propelling device;

2. an engaging block positioned to engage one of said objects; and

3. yielding means connecting said pull sleeve to said engaging block, whereby said yielding means absorbs at least a part of the impact of said object on said engaging block.

16. A dog as claimed in claim wherein said yielding means comprises a spring.

17. A dog as claimed in claim 15 wherein said yielding means comprises:

1. a bolt connected to said engaging block and slidable in said pull sleeve;

2. a spring co-axially disposed about said bolt; and

3. butting means mounted on said bolt at an end thereof remote from said pull sleeve, said butting means operating to trap said spring between said pull sleeve and said butting means, whereby said spring absorbs at least a part of the impact of said object on said engaging block.

18. A dog as claimed in claim 15 wherein said engaging block is pivotably mounted on said yielding means, said engaging block being pivotable from a position in which it can engage an incoming object to a position in which said engaging block cannot engage an incoming object.

19. In a unit carrier system in which a plurality of cars are driven over a trackway having merges therein, a merge assisting device for interleaving on an outgoing track cars approaching a merge on a plurality of different incoming tracks, said merge assisting device comprising:

a. a controlled-pathway, propelling device mounted adjacent to each of said incoming tracks, the distance upstream of said merge to which said controlled-pathway, reciprocating device extends being sufficient so that an incoming car approaching said device just after a dog (to be recited hereinafter) carried by said device has passed will be brought into synchronization by the following dog before said car has reached said merge; b. a plurality of dogs carried by at least one of said controlled-pathway, propelling devices, said dogs being spaced by a distance slightly in excess of the longest of said cars times the number of said incoming trackways and being positioned to engage an incoming car on the adjacent one of said incoming tracks and to remain in engagement with said car until it has reached an exit speed at least equal to the speed of the fastest of said incoming cars times the number of said incoming tracks; c. at least one dog i. carried by each of said controlled-pathway, propelling devices other than said at least one of said controlled-pathway, propelling devices and ii. positioned to engage an incoming car on the adjacent one of said incoming tracks and to remain in engagement with said car until it has reached an exit speed at least equal to the speed of the fastest of said incoming cars times the number of said incoming tracks;

(1. means for driving said controlled-pathway, propelling devices at said exit speed; and

e. means for synchronizing said controlled-pathway, propelling devices so that said cars reach said merge at intervals at least slightly in excess of the length of the longest of said cars, whereby said cars may be interleaved on said outgoing track without danger of collision with one another.

20. A merge assisting device as claimed in claim 19 wherein said one of said controlled-pathway, propelling devices comprises:

21. A merge assisting device as claimed in claim wherein said sprockets are driven in only one direction.

22. A merge assisting device as claimed in claim 20 wherein said sprockets are driven first in one direction, then in the other, whereby said dog is recocked for successive cars.

23. A merge assisting device as claimed in claim 20 wherein said dog is carried between two parallel chains.

24. A merge assisting device as claimed in claim 23 wherein said controlled-pathway, propelling device fur ther comprises guide means for supporting said parallel chains and preventing deviation thereof from their prescribed pathway during that portion of their prescribed pathway during which said dog is in position to engage said cars.

25. A merge assisting device as claimed in claim 20 wherein said means for driving said controlledpathway, propelling device includes torsional springs which normally transmit torque to said sprockets in the manner of a cylindrical shaft, but which absorb the impact of said cars on said dog by curling or .uncurling slightly.

26. A merge assisting device as claimed in claim 19 and further comprising means for absorbing the impact of said cars on said dogs.

27. A merge assisting device as claimed in claim 19 wherein said one of said controlled-pathway, propelling device extends from upstream of said merge at least to said merge.

28. A merge assisting device as claimed in claim 19 wherein said dog comprises:

1. a pull sleeve mounted on said controlled-pathway,

propelling device;

29. A merge assisting device as claimed in claim 28 wherein said yielding means comprises a spring.

30. A merge assisting device as claimed in claim 28 wherein said yielding means comprises:

1. a bolt connected to said engaging block and slidable in said sleeve;

2. a spring co-axially disposed about said bolt; and

31. A merge assisting device as claimed in claim 28 wherein said engaging block is pivotably mounted on said yielding means, said engaging block being pivotable from a position in which it can engage an incoming car on the adjacent one of said incoming tracks to a position in which said engaging block cannot engage incoming cars on the adjacent one of said incoming tracks.

32. A merge assisting device as claimed in claim 19 wherein said dog is pivotably mounted on said controlled-pathway, propelling device, said dog being pivotable from a position in which it can engage an incoming car on the adjacent one of said incoming tracks to a position in which said engaging block cannot engage incoming cars on the adjacent one of said incoming tracks.

33. In a unit carrier system in which a plurality of cars are driven over a trackway having merges therein, a merge assisting device for interleaving on an outgoing track cars approaching a merge on a plurality of different incoming tracks, said merge assisting device comprising:

a. a first controlled-pathway, propelling device mounted adjacent to a first one of said incoming tracks, the distance upstream of said merge to which said first controlled-pathway, propelling device extends being sufficient so that an incoming car approaching said first controlled-pathway, pro pelling device just after a dog (to be recited hereinafter) carried by said device has passed will be brought into synchronization by said dog on its next pass before said car has reached said merge,

b. a single dog i. carried by said first controlled-pathway, propelling device and ii. positioned to engage an incoming car on said first one of said incoming tracks and to remain in engagement with said car until it has reached an exit speed at least equal to the speed of the fastest of said incoming cars times the number of said incoming track;

c. an additional controlled-pathway, propelling device mounted adjacent to the other or each of the other additional incoming tracks;

d. at least one dog i. carried by the other or each of the other additional incoming tracks and ii. positioned to engage an incoming car on the adjacent one of said incoming tracks and to remain in engagement with said car until it has reached an exit speed at least equal to the speed of the fastest of said incoming cars times the number of said incoming tracks;

e. means for driving said controlled-pathway, propelling devices at said exit speed; and

f. means for synchronizing said controlled-pathway, propelling devices so that said cars reach said merge at intervals at least slightly in excess of the length of the longest of said cars,

whereby said cars may be interleaved on said outgoing track without danger of collision with one another.

34. A merge assisting device as claimed in claim 33 wherein said first controlled-pathway, propelling devices comprises:

35. A merge assisting device as claimed in claim 34 wherein said sprockets are driven in only one direction.

36. A merge assisting device as claimed in claim 34 wherein said sprockets are driven first in one direction, then in the other, whereby said single dog is recocked for successive cars.

37. A merge assisting device as claimed in claim 34 wherein said single dog is carried between two parallel chains.

38. A merge assisting device as claimed in claim 37 wherein said first controlled-pathway, propelling device further comprises guide means for supporting said parallel chains and preventing deviation thereof from their prescribed pathway during the portion of their prescribed pathway during which said dog is in position to engage said cars.

39. A merge assisting device as claimed in claim 34 wherein said means for driving said first controlledpathway, propelling device includes torsional springs which normally transmit torque to said sprockets in the manner of a cylindrical shaft, but which absorb the impact of said cars on said single dog by curling or uncurling slightly.

40. A merge assisting device as claimed in claim 33 and further comprising means for absorbing the impact of said cars on said single dog.

41. A merge assisting device as claimed in claim 33 wherein said first controlled-pathway, propelling device extends from upstream of said merge at least to said merge.

42. A merge assisting device as claimed in claim 33 wherein said single dog comprises:

1. a pull sleeve mounted on said controlled-pathway,

propelling device;

2. an engaging block positioned to engage an incoming car on the adjacent one of said incoming tracks;

and

43. A merge assisting device as claimed in claim 42 wherein said yielding means comprises a spring.

44. A merge assisting device as claimed in claim 42 wherein said yielding means comprises:

1. a bolt connected to said engaging block and slid able in said sleeve;

2. a spring co-axially disposed about said bolt; and

45. A merge assisting device as claimed in claim 33 wherein said engaging block is pivotably mounted on said yielding means, said engaging block being pivotable from a position in which it can engage an incoming car on the adjacent one of said incoming tracks to a position in which said engaging block cannot engage incoming cars on the adjacent one of said incoming

Claims

1. In a unit carrier system in which a plurality of cars are driven over a trackway having merges therein, a merge assisting device for interleaving on an outgoing track cars approaching a merge on a plurality of different incoming tracks without stopping said cars prior to the merge, said merge assisting device comprising: a controlled-pathway, propelling device mounted adjacent to each of said incoming tracks; at least one dog carried by each of said controlled-pathway, propelling devices and positioned to engage an incoming car on the adjacent one of said incoming tracks and to remain in engagement with said car until it has reached an exit speed at least equal to the speed of the fastest of said incoming cars times the number of said incoming tracks; means for driving said controlled-pathway, propelling devices at said exit speed; and means for synchronizing said controlled-pathway, propelling devices so that said cars reach said merge at intervals at least slightly in excess of the length of the longest of said cars, whereby said cars may be interleaved on said outgoing track without danger of collision with one another.

2. A merge assisting device as claimed in claim 1 wherein at least one of said controlled-pathway, propelling devices comprises: a chain and a plurality of sprockets for guiding said chain and imparting motion thereto.

2. a spring co-axially disposed about said bolt; and

2. an engaging blocK positioned to engage one of said objects; and

2. a spring co-axially disposed about said bolt; and

7. A merge assisting device as claimed in claim 2 wherein said means for driving said controlled-pathway, propelling device includes torsional springs which normally transmit torque to said sprockets in the manner of a cylindrical shaft, but which absorb the impact of said cars on said dog by curling or uncurling slightly.

8. A merge assisting device as claimed in claim 1 and further comprising means for absorbing the impact of said cars on said dogs.

10. A merge assisting device as claimed in claim 1 wherein said dog comprises:

15. A dog adapted to be mounted on a controlled-pathway, propelling device and to impart momentum to objects moving on a controlled path adjacent to said controlled-pathway, propelling device, said dog comprising:

16. A dog as claimed in claim 15 wherein said yielding means comprises a spring.

17. A dog as claimed in claim 15 wherein said yielding means comprises:

19. In a unit carrier system in which a plurality of cars are driven over a trackway having merges therein, a merge assisting device for interleaving on an outgoing track cars approaching a merge on a plurality of different incoming tracks, said merge assisting device comprising: a. a controlled-pathway, propelling device mounted adjacent to each of said incoming tracks, the distance upstream of said merge to which said controlled-pathway, reciprocating device extends being sufficient so that an incoming car approaching said device just after a dog (to be recited hereinafter) carried by said device has passed will be brought into synchronization by the following dog before said car has reached said merge; b. a plurality of dogs carried by at least one of said controlled-pathway, propelling devices, said dogs being spaced by a distance slightly in excess of the longest of said cars times the number of said incoming trackways and being positioned to engage an incoming car on the adjacent one of said incoming tracks and to remain in engagement with said car until it has reached an exit speed at least equal to the speed of the fastest of said incoming cars times the number of said incoming tracks; c. at least one dog i. carried by each of said controlled-pathway, propelling devices other than said at least one of said controlled-pathway, propelling devices and ii. positioned to engage an incoming car on the adjacent one of said incoming tracks and to remain in engagement with said car until it has reached an exit speed at least equal to the speed of the fastest of said incoming cars times the number of said incoming tracks; d. means for driving said controlled-pathway, propelling devices at said exit speed; and e. means for synchronizing said controlled-pathway, propelling devices so that said cars reach said merge at intervals at least slightly in excess of the length of the longest of said cars, whereby said cars may be interleaved on said outgoing track without danger of collision with one another.

20. A merge assisting device as claimed in claim 19 wherein said one of said controlled-pathway, propelling devices comprises: a chain and a plurality of sprockets for guiding said chain and imparting motion thereto.

21. A merge assisting device as claimed in claim 20 wherein said sprockets are driven in only one direction.

24. A merge assisting device as claimed in claim 23 wherein said controlled-pathway, propelling device further comprises guide means for supporting said parallel chains and preventing deviation thereof from their prEscribed pathway during that portion of their prescribed pathway during which said dog is in position to engage said cars.

25. A merge assisting device as claimed in claim 20 wherein said means for driving said controlled-pathway, propelling device includes torsional springs which normally transmit torque to said sprockets in the manner of a cylindrical shaft, but which absorb the impact of said cars on said dog by curling or uncurling slightly.

28. A merge assisting device as claimed in claim 19 wherein said dog comprises:

33. In a unit carrier system in which a plurality of cars are driven over a trackway having merges therein, a merge assisting device for interleaving on an outgoing track cars approaching a merge on a plurality of different incoming tracks, said merge assisting device comprising: a. a first controlled-pathway, propelling device mounted adjacent to a first one of said incoming tracks, the distance upstream of said merge to which said first controlled-pathway, propelling device extends being sufficient so that an incoming car approaching said first controlled-pathway, propelling device just after a dog (to be recited hereinafter) carried by said device has passed will be brought into synchronization by said dog on its next pass before said car has reached said merge, b. a single dog i. carried by said first controlled-pathway, propelling device and ii. positioned to engage an incoming car on said first one of said incoming tracks and to remain in engagement with said car until it has reached an exit speed at least equal to the speed of the fastest of said incoming cars times the number of said incoming track; c. an additional controlled-pathway, propelling device mounted adjacent to the other or each of the other additional incoming tracks; d. at least one dog i. carried by the other or each of the other additional incoming tracks and ii. positioned to engagE an incoming car on the adjacent one of said incoming tracks and to remain in engagement with said car until it has reached an exit speed at least equal to the speed of the fastest of said incoming cars times the number of said incoming tracks; e. means for driving said controlled-pathway, propelling devices at said exit speed; and f. means for synchronizing said controlled-pathway, propelling devices so that said cars reach said merge at intervals at least slightly in excess of the length of the longest of said cars, whereby said cars may be interleaved on said outgoing track without danger of collision with one another.

34. A merge assisting device as claimed in claim 33 wherein said first controlled-pathway, propelling devices comprises: a chain and a plurality of sprockets for guiding said chain and imparting motion thereto.

39. A merge assisting device as claimed in claim 34 wherein said means for driving said first controlled-pathway, propelling device includes torsional springs which normally transmit torque to said sprockets in the manner of a cylindrical shaft, but which absorb the impact of said cars on said single dog by curling or uncurling slightly.

45. A merge assisting device as claimed in claim 33 wherein said engaging block is pivotably mounted on said yielding means, said engaging block being pivotable from a position in which it can engage an incoming car on the adjacent one of said incoming tracks to a position in which said engaging block cannot engage incoming cars on the adjacent one of said incoming tracks.