US2802559A

US2802559A - Conveying mechanism

Info

Publication number: US2802559A
Application number: US476660A
Authority: US
Inventors: Paul A Hauck
Original assignee: Hanson Van Winkle Munning Co
Current assignee: Hanson Van Winkle Munning Co
Priority date: 1954-12-21
Filing date: 1954-12-21
Publication date: 1957-08-13
Anticipated expiration: 1974-08-13

Description

Aug. 13, 1957 P. A. HAUCK CONVEYING MECHANISM 3 Sheets-Sheet 1 Filed Dec. 21, 1954 /m m m w m Z Aug. 13, 1957 Filed Dec. 21, 1954 P. A. HAUCK CONVEYING MECHANISM 3 Sheets-Sheet 2 Aug. 13, 1957 P. A. HAUCK 2,802,559

CONVEYING MECHANISM Filed Dec. 21, 1954 I 3 Sheets-Sheet 3 i I 20c l5\ L @ZLNM Z ATTORNEYS Ugimd SW 8 tent 2,802,559 CONVEYING MECHANISM PanlA: Hauck; Union, N. 1.; assignor to Hanson-Van Winkle-Munning Company, Matawan, N. J., a corporation of New Jersey I fnp'pligaao December '21, 1954, Serial No. 476,660

7 Claims. (c1. 19s-1a tcernedwith processing machinery of the type described,

which includes novel conveying means for advancing the carriers step by step from a loading station along the treatment stations to an unloading station and for returning. theempty carriers to the loading station. The processing machinery of the invention may be employed for a variety of purposes and, since all its advantages are realized in its application to electroplating, a machine for such use and embodying the invention, will be illustrated and described in detail.

Automatic electroplating machines commonly include a group of preparation tanks for cleaning, etching, and like treatments, one or more plating tanks, and a group of, tanks for finishing treatments, such as reclaiming, rinsing, hot rinsing, etc. In conventional machines, a plurality of workpieces are placed upon racks and the loaded racks are mounted upon carriers at a loading station. The carriers are then advanced step by step along the machine by conveying means and an elevator operating in the periods of rest of the conveying means raises and lowers the carriers, so that they can pass over the endof each tankand be lowered to the following tank. The preparation and finishing treatments are of relatively short duration, so that theworkpieces are lowered into the tanks and raised therefrom on the next ascent of the elevator. The plating operation takes longer and, accordingly, the plating tanks may be of considerable length and the workpieces lowered into a plating tank may be plated while being moved along the tank within the platingsolution. Other machines operate in a skip-stop cycle, and the plating is carried on at stations in plating tanks, to which the carriers removed from the last preparation Itank are transferred in sequence, until all the stations are filled. Thereafter; the carriers are removed from the stations in the order in which they were delivered to the stations. In both kinds ofplating operation, the carriers removed from the plating tanks are moved along the group of finishing tanks for treatment therein and, after the last finishing treatment, the loaded-racks are removed from the carriers at an unloading station and the emptycarriers are returned to the loading station. In electroplating machines of either typc,,it is common practice to provide a separate conveyor and elevator for each of the groups of preparation and finishing tanks and for the plating stations. -In electroplating machines, it is desirable that the empty carriersbe returned to the loading station by a single conveyor, which removes the carriers from the finishing tank conveyor and delivers themto the preparation-tank conveyor while both the latter conveyors are at rest. It is also desirable that the return conveyor be is nearly continuous movement as possible, so that loading and loading stations may be kept to a .The lengths of the period of movement and the period of rest in a cycle of operation of the preparation and finishing tank conveyors are ordinarily the same, but the cycles are not in synchronism. Accordingly, it is difiicult to operate the return conveyor in proper timed relation to the two conveyors and have little interruption in the movement of the return conveyor.

I Thepresen invention is, accordingly, directed to novel conveying means for use in processing machinery as described, which advances workpiece carriers step by step along treatment stations by a plurality of conveyors to an unloading station and returns the empty carriersto a loading station by a single conveyor operating almost continuously. The conveying means are so constructed that exact timing of the return conveyor in relation to the conveyors at the loading and unloading stations is unnecessary and the almost uninterrupted operation of the return conveyor makes it possible to run the conveyor at a relatively low speed and, at the same time, keep the number of empty carriers in return transit to a minimum.

For a'better understanding of the invention, reference may be made to theaccompanying drawings, in which Fig. l is a diagrammatic view in side elevation of an electroplating machine, in which the new conveying systemv is employed;

' Fig. 2 is a side elevational view of a portion of the conveying system near the loading station;

Fig. 3 is a sideelevational view of a portion of the machine near the unloading station; Fig. 4 is a sectional view on the line 4-4 of Fig. 3; and l v i .Fig. 5 is a time chart.

The machinesillustrated includes preparation or preplating tanks 10,.plating tanks 11, and finishing or postplating tanks 12 and the workpieces W are carried along the tanks on racks 13, which are nrounted on carriers 14 at a loading station in front of the first of the preplating tanks. Each carrier comprises an axle 15 having flanged wheels 16 at its ends and a sleeve 17 encircles the axle and is provided with a pair of hooks 18, in which the top bar 13a of a rack may be inserted. The wheels of the carriers roll on tracks lying on opposite sides of the tanks and formed by angle irons 19 attached to beams 19a of

elevator structures

20a, 20b, 20c, extending along the pro-plating, the plating, and the postplating tanks, respectively. The elevator structures are of conventional construction and they are vertically movable in guideways on the framework 21 of the machine by the usual mechanism.

The carriers are advanced along the tracks over. the pre-plating tanks by a conveyor 22 and

conveyors

23 and 24 advance the carriers along the tracks over the plating and post-plating tanks, respectively. The conveyors are of the same construction and the details of conveyor 24 are illustrated in Figs. 3 and 4. The conveyor is formed of a pair of endless chains 25 lying in vertical planes in upper and lower horizontal stretches. Each chain is provided with rollers 26 and the rollers in the horizontal stretches of the chains run on guides 27. The means on the chains .for engaging and advancing the carriers are yokes 28 formed of plates, which are attached to links of the chains and have recesses 28a for receiving the axle 15 of a carrier. Each chain is trained about notched wheels 29 on shaft 30 and one of the shafts is driven by a motor 31 connected to the shaft through a speed reducer 32 and a drive chain 33.

umber of'idlejcarriers in transit between the unanismldisclosedin. my" co-pending application, ;Serial No,

443,193; filed July 14, 1954, may be used for the purpose, if desired. 'Each'loaded carrier is thenrmoved along the tracks of the elevator 20a over the pre-plating tanks 10 by conveyor 22 and broughtto rest above the tanks .succe'ssively; In each period of rest, the elevator moves down to immerse workpieces on carriers on theelevator in the tanks and then rises. When a loaded-carrier reaches the last pre-plating tank "10a, it is transferred to the tracks of the elevator 20b extending over the plating tanks. Adjacent the ends of the tracks, the two elevators lie close together and the tracks of elevator 29!; extend over tank 10a. The transfer of a carrier from the tracks of elevator 20a to those of elevator 20b may then be effected by suitable mechanism, such as a 'hydran'liccylinder 34 mounted on tank 10a in such position that its piston 34a can be operated to move a carrier along the top'of the tank from the place Where it has deposited by elevator 20a to a position, in which it will be picked up by elevator 20b.

The loadedcarriers removed from the last pre-p'lating tank 10a are advanced along the tracks of elevator 2012 by conveyor 23 and are deposited in the plating tanks in accordance with a skip-stop cycle. When the plating of the workpieces on a carrier has been completed, the carrier is picked up by elevator 20b on the .next' ascent of that elevator and the carrier is then advanced along the rails of conveyor 20b to the end of the rails. 20b partially overlies the first post-plating tank 12a. and its rails terminate close to those of elevator 20c. When a carrier has been deposited in tank 12a byelevator 2072-, it is moved along the tank to a position, in which it can be picked up by elevator 20c, and the mechanism for this purpose may be a hydraulic cylinder 35 functioning in the same manner as cylinder 34.

When a carrier has been advanced along all thepostplating tanks, it comes to rest at an unloading station adjacent the end of the rails on conveyor 20c and the loaded rack with the finished workpiece is removed from' the carrier by suitable means, such as the transfer mechanism disclosed in my co-pending application, a'bove identified. The empty carrier is'then moved up to the upper horizontal'stretch ofthe chains of conveyor 24 and, in such movement, the carrier is guided by curved guides 36, which retain it in its yokes 28 on conveyor 24. .The empty carriers are returned from conveyor .24 to conveyor 22 by a return conveyor 37, which is of the same construction as the other conveyors and includes chains 38 having upper and lower stretches and rollers 39 on the chains, which run on tracks 40 beneath the horizontal stretches. The chains are provided, with aligned pairs of pusher elements 41, 42 (Fig. 2'), and the plates of each pair are spaced to receive the axle 17 of a carrier between them. The pusher elements in the upper horizontal stretch of conveyor 37 return the empty carriers and, during the return moveinentof the carriers, their rollers run on tracks formed by beams 43 mounted on the framework of the machine. 7 The return conveyor 37 intersects the upper stretches of

conveyors

22 and 24 near the ends of those stretches. The intersections of conveyor 37 with conveyor 24 occurs at aligned points 44, at which yokes 28 on conveyor 24 come to rest during the stepwise movement of the conveyor. Adjacent points .44, the chains 38 of conveyor 37 pass around notched wheels 45 and the wheels are so disposed that, as aligned pairs of

pusher elements

41, 42 .on chains 38 move by the points, the elements 42 pass at one side of the axle of a carrier in yokes 28. at points 44, while the elements 41 engage the axle to advance the carrier. Upper and lower curved guides 46 lead from points 44 to insure that the carrier removed from yokes will be properly engaged and advanced by conveyor 37.'

The chains 38 of conveyor 37 are led'about notched wheels 47 close to the place where conveyor 37 intersects conveyor 22, and adjacent the notched wheels, upper and lower'guides 48 are mounted in such relation to con- Conveyor v 4 veyor 37 that the axle of a carrier being moved by

pusher elements

41, 42 will enter the guides and thus leave the conveyor to travel through the guides by gravity. The conveyor 22 is so constructed thatv apair of yokes 28 thereon come to rest at points 49 just beyond the wheels 47 and the guides 48 lead to those yokes. As the, carriers are of substantial weight, a resilient bumper 50 is disposed at points 49 in such position as to cushion the carriers as they enter a pair of yokes. Beyond points 49, upper and lower tracks 51 guide carriers being advanced in yokes 28 on conveyor 22 and direct such carriers tothe tracks of elevator 20a.

The time chart forming .Fig. 5 discloses one. cycle of operation of the

conveyors

22,24, and 37'and parts of the preceding and succeeding cycles. The

conveyors

22 and 24 each operate in a cycle, in which there is a single movement and a period of rest of substantially greater duration than the length of the period of movement. The movement of conveyor 22 terminatesbe'fore the'movement of conveyor 24 starts and, when conveyor 24'stops, both

conveyors

22 and 24 remain at rest'for'a considerable period. The conveyor 37 operates in a cycle, which'includes a long period of movement and a'short period of rest. The movement of-conveyor 37 preferably starts simultaneously with the :stopping of conveyor '24'and continues, throughout the common period of rest of '

conveyors

22 and 24 and to a time during'the next period of movement of conveyor 24.

vA cycle of the conveying system made up of the three conveyors may be considered to start 'atthe time A. Atithis instant, conveyor 24 has just come to rest with an empty carrier supported in yokes at points 44. As conveyor 24 stops, conveyor 37 may be started in any desired manner, as, for example, by means of a limit switch LSr'mounted near points 44 and having an operating arm actuated by a carrier as it approaches points 44. With the stopping of conveyor 24, that conveyor and conveyor 22 have a period .of rest in common and, during this period, aligned pairs of

pusher elements

41, 42 on conveyor '37 engage and remove an empty carrier from conveyor 24 at points 44 and other pusher elements a deliver an empty carrier to the yokes on conveyor 22 at points 49. In order that there may be an ample margin of safety in the timing of the conveyors, the conveyor 37 has been stopped with aligned pairs of. pusher elements thereon at points 5.2 and 53, which are in front of and spaced from points 49 and 44, respectively. The stopping ofconveyor .37 as described may be effected by means of a limit switch LS2 having an operating arm, which is engaged by a carrier as it reaches points 52. When conveyor 37 is startedfit runs for a period represented by the distance between times A and B, before the pusher, elements travel. from points 52 to points 49 and from points 53 to points 44. As the elements reach the respective points, one set dis charges an empty carrier, which is guided into a pair of yokes on conveyor 22, while the other set removes an empty carrier from yokes of conveyor 24 and starts its return. As the discharge and removal of the carriers occurs well after conveyor 37 has started and within the common period of rest of conveyors 22 and 24', exact timing of the conveyor movements is not required. When conveyor 37 has delivered a carrier to conveyor 22 and removed a carrier from conveyor 24,

conveyors

22 and 24 may be operated and, during their movement, conveyor 37 may continue in operation, until it is stopped .by limit switch LS2. The time, at which conveyor .37 stops, is represented by point C on the time chart and it occurs during a'period of movement of conveyor 24. It will be noted that the time in each cycle of the conveying system, during which conveyor 37 is moving, is much longer than the periods of movement of 'conveyors22and 24. Accordingly, conveyor 37 may'move at a relatively low speed and still return carriers from conveyor 24 tofconveyor 22 with only a few carriers'in transit at any time.

' The machine shown comprises three conveyors 22, .23,

and 24 between the loading and unloading stations but, since only the first conveyor 22 and the last conveyor 24 cooperate with the return conveyor 37, the intermediate conveyor 23 may be omitted, if desired, or it may be replaced by as many other conveyors as are needed.

I claim:

1. A processing machine, which comprises a plurality of workpiece carriers, first and second conveyors disposed in alignment and operating intermittently with a period of rest in common between successive movements, spaced attachments on the conveyors for releasably engaging and advancing the carriers, means for transferring the carriers from the first conveyor to the second, a third conveyor intersecting the paths of the first and second conveyors near points, at which attachments thereon come to rest in the intermittent movement of the first and second conveyors, spaced attachments on the third conveyor operating to remove carriers from the second conveyor at the point of intersection of the third conveyor with the path of the second conveyor for transport by the third conveyor and to discharge the transported carriers near the point of intersection of the third conveyor with the path of the first conveyor, means for receiving each discharged carrier and delivering it to an attachment on the first conveyor, means for stopping the third conveyor with a pair of attachments thereon adjacent to and in front of said points of intersection, respectively, and means for starting the third conveyor in time to cause said pair of attachments to pass said points of intersection, while the first and second conveyors are stopped.

2. The machine of claim 1, in which the means for stopping the third conveyor is actuated by an element moving with that conveyor.

3. The machine of claim 1, in which the means for starting the third conveyor is actuated by an element moving with the second conveyor.

4. The machine of claim 3, in which the means for starting the third conveyor is actuated simultaneously with the stopping of the second conveyor.

5. The machine of claim 2, in which each movement of the second conveyor terminates after the end of the corresponding movement of the first conveyor and the third conveyor is stopped by its stopping means during the movement of the second conveyor.

6. The machine of claim 1, in which the means for receiving each discharged carrier includes guide means, along which the carrier moves by gravity, and cushioning means for arresting the movement of the carrier.

7. The machine of claim 1, in which each of the conveyors includes at least one endless chain having an upper and a lower horizontal stretch, the third conveyor intersects the paths of the first and second conveyors near points, at which attachments on the upper stretches of the first and second conveyors come to rest in the intermittent movement of the first and second conveyors, and attachments on the upper stretch of the third conveyor advance carriers with that conveyor from the point of intersection of the third conveyor with the path of the second conveyor to approximately the pointof intersection of the third conveyor with the path of the first conveyor.

References Cited in the file of this patent UNITED STATES PATENTS 1,837,605 Baker Dec. 22, 1931