US3541963A

US3541963A - Tow truck switching means

Info

Publication number: US3541963A
Application number: US730881A
Authority: US
Inventors: Karl R M Karlstrom
Original assignee: American Chain and Cable Co Inc
Current assignee: FKI Industries Inc
Priority date: 1968-05-21
Filing date: 1968-05-21
Publication date: 1970-11-24
Anticipated expiration: 1987-11-24
Also published as: DE1925192A1; GB1225213A

Description

United States Patent Inventor Karl R. M. Karlstrom o Roseville, Michigan Appl. No. 730,881

Filed May 21, 1968 Patented Nov. 24, 1970 Assignee American Chain and Cable Company, Inc.

New York, New York a corporation of New York TOW TRUCK SWITCHING MEANS 22 Claims, 7 Drawing Figs.

US. Cl 104/88, 104/ 172 Int. Cl. B61] 3/04 Field 01' Search 104/88, 96, 172

References Cited UNITED STATES PATENTS 3,081,710 3/1963 Dehne 104/88 3,316,856 5/1967 Edgar 104/88 3,406,638 10/1968 Braun 104/88 3,418,945 12/1968 Stevenson et al 104/172 Primary Examiner-Arthur L. La Point Assistant Examiner-Robert Saifer Attorney-Barnes, Kisselle, Raisch & Choate ABSTRACT: A tow truck conveyor system comprising a track defined by slots in the floor including a main track portion and a branch track portion. A plurality of tow trucks with tow pins extending downwardly in the slots are movable along the main track portion by a chain operating beneath the floor. A switch tongue is provided at the area of juncture of the main track portion and the branch track portion. The switch tongue is operated when signal reader elements in the floor are engaged by signal members on the tow truck.

'Pa tented Nov. 24, 1970 Sheet INVENTOR. KARL R. M. KARLSTROM ATTORNEYS 'Paten ted Nov. 24, 1970 Sheet 2 of3 IN.VENTOR. KARL R. M. KARLSTROM ATTORNEYS Patented Nov. 24, 1970 3,541,963

Y// 4O 3 L 20 l6 I ////,I l k:\ I mum I i 26 I i ,9 27 I 5 I 2/ FIG. 7

INVENTOR. KARL. R. M. KARLSTROM ATTORNEYS TOW TRUCK SWITCHING MEANS This invention relates to conveyor systems and particularly to tow truck conveyor systems.

It is common'to provide a conveyor system with tow trucks that have tow pins that extend downwardly into slots, which define the track in the floor, into engagement with a chain beneath the floor to pull the tow trucks along the floor. In the handling of such tow trucks, it is also common to have branch track portions and switch tongues for diverting the tow trucks to the branch track portion.

Among the objects of this invention is to provide a simple low cost system for actuating the switch tongue in response to signals from the tow truck, which system utilizes a minimum number of parts, is easy to maintain, occupies a small space vertically in the floor, and has long life.

In the drawings:

FIG. l is a fragmentary plan view ofa system embodying the invention.

FIG. 2 is a fragmentary view similar to FIG. I of a modified system showing the parts in a different position.

FIG. 3 is a fragmentary vertical view through a portion of the system.

FIG. 4 is a view similar to FIG. I on an enlarged scale with parts broken away.

FIG. 5 is a fragmentary sectional view on an enlarged scale taken along the line 5-5 in FIG. 4.

FIG. 6 is a fragmentary sectional view on an enlarged scale taken along the line 6-6 in FIG. 4.

FIG. 7 is a fragmentary sectional view taken along the line 7-7 in FIG. 4.

Referring to FIGS. 1 and 3, the system embodying the invention comprises a-floor 10 having a slot 11 therein which defines a main track and a slot 12 intersecting the slot 11 and defining a branch track. A plurality of carriers in the form of tow trucks 13 having wheels 14 are provided. Each tow truck 13 includes a tow pin 15 extending downwardly through the slot 11 into engagement with a trolley or pusher 16 that is fixed to a chain 17 driven in a manner not shown.

At the area of juncture of the main track 11 and branch track 12 a switch tongue 18 is provided. As shown in FIGS. 4 and 7, the switch tongue 18 is provided with a tube 19 which is telescoped over a fixed shaft 20 that extends between a floor plate 10a and a frame or housing 21. A latch lever 22 is also fixed to the tube 19/ Latch lever 22 is yieldingly urged in a direction tending to move the switch tongue into position where itwill divert a tow pin 15 by a spring 23 that is fixed at one end to the latch lever 22 and at the other end to a support 24 fastened to the housing 21. The switch tongue 18 is normally held out of the position wherein it would divert the tow pin ofa tow truck by a plurality of latches 25 which are pivoted on a shaft 26 that is fixed to the housing 21 and extends vertically. Each latch 25 includes a notch 26 that engages a roller 27 on the latch lever 22. The rollers 27 are rotatably mounted on a pin 28 that extends vertically upwardly from the latch lever 22 (FIG. 7). Each latch 25 is urged against the roller 27 of its respective latch lever 22 by a spring 251; which is connected at one endto the latch 25 and at the other end to the housing 21.

Referring to FIGS. 1, 4 and 5, each latch 25 has a signal reader element 29 associated therewith. Each signal reader element is pivoted to a bracket 30 fixed to housing 21 and is adapted to swing upwardly and rearwardly to the broken line position shown in FIG. 5 through an opening 32 in the fioor plate 10a into the path of a signal member 33 on the tow truck. Each signal reader element 29 is urged toward a position downwardly and forwardly within the floor by a tension spring 34 that is fixed at one end to the signal reader element 29 and at the other end to a bracket 35 on housing 21. A cable C is fixed at one end to each latch 25 by a lever 36 and at the other end to its respective signal reader element 29 as at 37. Each cable C is trained over a pair of

pulleys

38, 39 mounted on

brackets

40, 41 fixed t0 the frame 21 for rotation about vertical axes. Each cable C is further trained over a pulley 42 rotatably mounted on a bracket 43. A spring 36a has one end thereof connected to lever 36 and the other end thereof connected to housing 21 to take up any slack in cable C.

As shown in FIGS. 4 and 6 all ofthe pulleys 38 are mounted on the single bracket 40. In the same manner, all of the pulleys 39 are mounted on the single bracket 41. As shown in FIGS. 1 and 4, two signal reader elements are provided in side by side relation in one of a plurality of positions P shown in broken lines in FIG. I.

In order to elevate the signal reader elements 29 into the path of the tow truck when it approaches the area of juncture of the main track and branch track, a conditioning lever 44 is pivoted about a vertical axis on a pin 45a and extends in the direction of travel of the tow trucks for swinging movement into and out of the path of the tow pin as it moves in the slot 11. An idler pulley 45 for each cable C is mounted on a bracket 46 on lever 44. The reach R of each cable C between its

pulleys

38, 39 extends adjacent its respective pulley 45.

Lever 44 is normally in the path of the tow pins 15. As a tow truck approaches and its tow pin 15 engages the lever 44. the lever is swung laterally or downwardly as viewed in FIG. 4, bringing the pulley 45 into contact with the cables and applying tension to the cables to elevate the signal reader elements 29 to the broken line position shown in FIG. 5. As the tow truck is moved further along the slot, if the signal reader elements 33 are properly positioned and correspond in position to the position of the signal elements 33 on the tow truck, the signal reader elements 29 will be engaged and swung downwardly and forwardly. This movement of signal reader elements 29 applies tension to the cables C to pull the latch elements 25 out of engagement with the rollers 27 on latch lever 22 releasing the latch lever 22 to permit the spring 23 to swing the switch tongue 18 into the path of the tow pin and thereby divert the tow truck (FIG. 1). If the signal elements 33 on the tow truck are not positioned properly, for example, if only one of a plurality of signal reader elements are engaged or none is engaged, at least one of the latches 25 will remain in engagement with the latch lever '22 so that the switch tongue will not be actuated.

In order to prevent diverting the tow truck into a branch slot 12 which already has a carrier therealong, a choke system is provided which includes choke latch 50 pivoted on the shaft 26 and having a notch therein engaging one of the rollers 27 on latch lever 22. The choke latch 50 is normally held out of engagement with its respective roller by a spring 51 operating through a lever 52. However, if a tow truck is present in the branch'slot 12, its tow pin will engage a lever 52 in the slot 12 applying tension to a cable 53 trained over a pulley 54 to urge the choke lever 50 into engagement with the latch lever 22 thereby preventing the latch lever 22 from moving and, in turn, the switch tongue from moving to the diverting position.

In the form of the invention shown in FIG. 2, two additional 7 signal reader elements 29 and associated latches 25, pulleys ments 33 on the tow truck.

Although the system has been described in connection with asubfloor conveyor system, it is also applicable to overhead power and free conveyor systems comprising main and branch tracks with an associated switch tongue.

Iclaim: 1. The combination comprising: a track including a main track portion and a branch track portion; a carrier movable along said track; switch means at the area of juncture of the main track portion and branch track portion for diverting the carrier from the main track portion to the branch track portion;

latch means forfholding said switch means in one of its two positions;

means yieldingly urging said switch means to its other position; 1

a flexible element connected to said latch means;

at least one signal reader element movable into and out of the path of the carrier;

means in the path of the carrier and operable by the approach of a carrier to apply tension to said flexible element to move said signal reader element into the path of the the carrier; and

signal means on the carrier operable when properly positioned to engage said signal reader element and apply further tension to said flexible element to disengage said latch means and permit said switch means to move to its other position under the action of said yielding means.

2. The combination set forth in claim 1 wherein said signal reader element is movable in such a manner that it swings out and rearwardly into the path of the carrier and in and forwardly out of the path of the carrier.

3. The combination set forth in claim 1 including a plurality of said signal reader elements and a flexible element and latch means individual to each said reader element.

4. The combination set forth in claim 1 wherein said means in the path of said carrier and operable to apply tension to said flexible element comprises a member pivoted adjacent the path and normally in the path of the carrier.

5. The combination set forth in claim 4 wherein said flexible element has a reach thereof extending across a pair of pulleys, said last-mentioned means having a pulley engaging said reach to apply said tension to said flexible element upon movement of said last-mentioned means.

6. The combination set forth in claim 1 including a choke element operable upon said latch means, said choke element being engaged by a carrier along said branch track portion to prevent disengagement of said latch means.

7. The combination set forth in claim 1 including means yieldingly urging said signal reader element in a direction out of the path of said carrier.

8. The combination set forth in claim 1 including means yieldingly urging said latch means into engagement with said switch means;

9. The combination set forth in claim 1 wherein said switch means comprises a switch tongue pivotally mounted adjacent the area of juncture of-said main track portion and branch track portion, said latch, means including latch elements pivoted adjacent said s'witch tongue and engaging said switch tongue.

10. The combination comprising:

a floor having slots therein defining a main track portion and a branch track portion;

a conveyor driven beneath said floor along said main track portion; v

a tow truck movable along said floor;

said tow truck having a tow pin extending downwardly through said slot in said floor into engagement with said conveyor;

switch means at the area of juncture of the main track portion and branch track portion for diverting the tow pin of the tow truck from the main track portion to the branch track portion;

latch means for holding said switch means in one of its two positions;

means yieldingly urging said switch means to its other posi tron;

a flexible element connected to said latch means;

at least one signal reader element movable upwardly into and out of the path of the tow truck;

said flexible element being attached to said signal reader element;

means in the path of the tow truck and operable to apply tension to said flexible element to move said signal reader element into the path of the tow truck; and

signal means on the tow truck operable when properly positioned to engage said signal reader element and apply further tension to said flexible element to disengage said latch means and permit said switch means to move to its other position under the action of said yielding means.

11. The combination 34 set forth in claim 10 wherein said signal, reader element is movable in such a manner that it swin s upwardly and rearwardly into the path of the tow truck and ownward y and forward y out of the path of the tow truck.

12. The combination set forth in claim 10 including a plurality of said signal reader elements and a flexible element and latch individual to each said reader element.

13. The combination set forth in claim 10 wherein said means in the path of said tow truck and operable to apply tension to said flexible element comprises a member pivoted adjacent main track portion and normally in the path of the tow pin of the tow truck.

14. The combination set forth in claim 13 wherein said flexible element has a reach thereof extending across a pair of pulleys, said last-mentioned means having a pulley engaging said reach to apply said tension to said flexible element upon movement of said last-mentioned means.

15. The combination set forth in claim 10 including a choke element operable upon said latch means, said choke element being engaged by the tow pin of a tow truck along said branch track-portion to prevent disengagement of said latch means.

16. The combination set forth in claim 10 including means yieldingly urging said signal reader element in a direction out of the path of said tow truck.

17. The combination set forth in claim 10 including means yieldingly urging said latch means into engagement with said switch means.

18. The combination set forth in claim 10 wherein said switch means comprises a switch tongue pivotally mounted adjacent the area of juncture of said main track portion and branch track portion, said latch means including latch elements pivoted adjacent said switch tongue and engaging said switch tongue.

19. The combination set forth in claim 10 including a plurality of said signal reader elements in laterally disposed relation adjacent the path of the carrier, a flexible element and latch means individual to each said signal reader element.

20. The combination set forth in claim 19 wherein at least one of said signal reader elements is on an opposite side of said main track portion.

21. The combination set forth in claim 1 including a plurality of said signal readerelements in laterally disposed relation adjacent the path of the carrier, a flexible element and latch means individual to each said signal reader element.

22. The combination set forth in claim 21 wherein at least one of said signal reader elements is on an opposite side of said main track portion.