US2709512A

US2709512A - Processing machines

Info

Publication number: US2709512A
Application number: US437092A
Authority: US
Inventors: Thomas H Curtis
Original assignee: Hanson Van Winkle Munning Co
Current assignee: Hanson Van Winkle Munning Co
Priority date: 1954-06-16
Filing date: 1954-06-16
Publication date: 1955-05-31
Anticipated expiration: 1972-05-31

Description

W 1955 T. H. CURTIS 2,709,51

PROCESSING MACHINES Filed June 16, 1954 5 SheetsSheet 1 l iXl? l' K [M 67% 34a 22 4O 3 H 3 E R E; f

.INVENTOR. THOMAS H. CURTIS ATTORNEYS l, 1955 11+ cums 2,709,512

PROCESSING MACHINES Filed June 16, 1954 5 Sheets-Sheet 2 IN V EN TOR.

THOMAS M. CU RTIS BY ATTOR N E YSi United States Patent O PROCESSING MACHINES Thomas H. Curtis, Fairhaven, N. J., assignor to Hanson- Van Winkle-Manning Company, Matawan, N. J., a corporation of New Jersey Application June 16, 1954, Serial No. 437,092

12 Claims. ((31. 198-491) This invention relates to processing machinery, on which workpieces are automatically subjected to chemical, electrolytic, and other similar treatments. More particularly, the invention is concerned with a novel automatic processing machine, on which a succession of workpieces can be rapidly and efficiently processed with dilferent workpieces given different treatments in accordance with their requirements. The need for giving workpieces different treatments on the same machine is disclosed in my Patents 2,605,882, issued August 2, i952, and 2,626,621, issued January 27, 1953, and in my co-pending application Ser. No. 156,627, filed April 18, 1950, and now Patent No. 2,685,954, of which this application is a continuation-in-part. The situation may be explained briefly as follows.

in the electroplating of workpieces, for example, it is frequently desirable that some pieces be plated more heavily than others, as, for instance, the hardware used inside automobiles need not be as heavily plated as the exterior hardware, since it is not exposed to as severe weather conditions. The plating on both kinds of hardwere is of the same type and it has been found that, in both cases, the conditions of plating, such as the temperature and composition of the bath, the current density, etc., should be maintained within relatively close limits. Accordingly, it is undesirable to produce a light plating on certain workpieces by cutting oil the plating current while the pieces are in the plating bath, because such operation of the plating cycle materially detracts from the quality of the finish. The consequence is that plating machines of the type now in common use, when set up to provide the desired heavy plating on some workpieces, are ordinarily not adapted to apply a satisfactory plating of lighter weight on other workpieces.

in other instances, it may be desired to subject Workpieces being handled on processing machines to treatments in different series of baths or for different periods. Such selective treatment of workpieces cannot be effected on conventional prior processing machines, since they are relatively inflexible in operation and can carry out only a single treatment cycle at a time.

The present invention is directed to the provision of a novel automatic processing machine provided With selectively adjustable means permitting different workpieces to be caused to undergo different treatment cycles. The processing machine of the invention is provided with means, by which groups of workpieces are raised and lowered and advanced horizontally, and other means, by which individual workpieces may be raised and lowered independently. The action of such individual raising and lowering means may be controlled by the carriers for the workpieces and it is thus possible to treat such individual workpieces in cycles different, from the nor mal treatment cycle of the machine.

For a better understanding of the invention, reference may be made to the accompanying drawing, in which:

Fig. l is a diagrammatic plan view of a part of the ice processing machine constructed in accordance with the invention;

Fig. 2 is a sectional view of a bridge used in the machine illustrated in Fig. l, the view being taken on the line 2-2 of Fig. 1;

Fig. 3 is a sectional view of a bypass used in the machine shown in Fig. 1, the view being taken on the lines 33 of Figs. 1 and 4;

Fig. 4 is a sectional view on the line i-4 of Fig. 3;

Fig. 5 is a sectional view on the line 55 of Fig. 6 of a unit elevator employed in the processing machine shown in Fig. 1;

Fig. 6 is a sectional view of the unit elevator taken at right angles to Fig. 5;

Fig. 7 is a fragmentary view of parts shown in Fig. 6 but illustrated in different positions;

Fig. 8 is a diagrammatic view of control means employcd in connection with the unit elevator;

Fig. 9 is a diagrammatic view of a modified form of the elevator;

Fig. 10 is a fragmentary view of control means for the mechanism shown in Fig. 9; and

Figs. 11 and 12 are plan and elevational views, respectively, of a modified control means for the machine.

The processing machine illustrated diagrammatically in Fig. 1 is of the type employed in electroplating operations and it comprises a plurality of pre-treatment stations 26 shown as tanks, a treatment station 21 having a plurality of treatment positions and taking the form of a long tank of U-shape, and a plurality of posttreatment stations or tanks 22. The machine includes a frame, conveyor chains, main elevators, and drive means for the conveyor chains and main elevators, all of which may be substantially as illustrated and described in my Patents 2,605,882 and 2,662,621 mentioned above.

The frame of the machine indicated generally at 23 extends along the tanks at one side thereof and includes an upper channel 24 receiving a conveyor chain 25 and a lower channel 26 receiving a conveyor chain 27. The chains are connected at intervals by vertical track members 28 arranged in pairs and forming enclosed tracks for rollers 29 on skate-like carriages 30. Each carriage is provided with an arm 31 extending laterally to overlie the tanks and a pick-up roller 32 lying outside the track between members 28 and in position to be engaged by an angle iron 33 on main elevators 34, 34a. Main elevator 34 extends along the pre-treatment tanks 24 to the first treatment position of tank 21 and main elevator 34a extends from the last treatment position of tank 21 to the end of the last post-treatment station. The main elevators move the carriages 3t} relatively to the conveyor between upper and lower positions and support the carriages in their upper positions, while the conveyor is operating. The track members 28 of each pair are connected at their lower ends by a block 35 provided with a roller 36 running on the upper flange of a beam 23a forming part of the machine frame and, when a carriage 30 is in its lower position, its lower roller 29 rests in a seat in the block 35.

Near its end and in line with the first treating position in tank 21, the elevator 34 carries spaced brackets 37, between which is pivoted a plate or flipper 33. The flipper is normally held against the top of the brackets, as shown in Fig. 4, by springs 39 and, in such position, forms a continuation of the angle iron 33. An angle iron serving as a fixed track 49 is mounted on the frame of the machine in alignment with the angle iron 33 of elevator 34, when the latter is in its high position, and one end of the track overlies the outer bracket 37 on the elevator. The angle iron 33 is cut away above the inner bracket 3'7 and, between the end of the angle iron and the end of the track, a bypass, generally indicated at 41, is mounted on the machine frame.

The by-pass comprises a horizontal plate 42 adapted .to span the space between the ends of the lower flanges of angle iron 33 and track 4t; and to lie against the top of flipper 3S and the plate has beveled side edges. Plate 42 is mounted on a block 43 and the block is movable on vertical guide rods 44 attached to the machine frame. The block can be moved by a rod 45, which projects through an opening in the frame and is urged upwardly by an encircling spring 46. At its upper end, the rod is connected to one end of a lever 47 having its other end pivoted on a standard 48, the lever being acted on between its ends by the plunger of a solenoid Si. Normally, the plate 42 is held in elevated position ou t of contact with the top of flipper 33 by spring 46, but the plate may be lowered by energization of solenoid S1 to lie on top of the flipper. When the plate is in this position, the roller 32 of a carriage 3t brought to rest at the first treatment position of tank 21 lies on top of plate 42 and, when the elevator 34 moves down, the carriage remains on plate 42 and is not lowered. When plate 42 is raised above the flipper 38 by its spring 46, the roller 32 of a carriage advanced to the first treatment position in tank 21 comes to rest on top of flipper 33, and, when elevator 34 is lowered, the carriage moves down with the elevator.

At one or more treatment positions along the tank 21, the track 40 may be cut away and, at each of these gaps in the track, there is placed a unit elevator, as illustrated in Figs. 5 and 6. The unit elevator comprises a flipper 49 pivotally mounted on a plate 56 and urged to horizontal position by a spring 51. The plate 50 is vertically movable on fixed guide rods 52 on the machine frame I and is connected by an arm 53 to a chain 5 which is trained around an upper sprocket wheel 55 on the shaft 56 of a motor 57 and about a lower sprocket wheel 53 journaled for free rotation on the machine frame. The chain is provided with a lug 59 engageable with rollers on operating arms of respective switches 60, 61 at opposite ends of the desired travel of the chain.

When the unit elevator is in its upper position, its flipper 49 lies in line with the horizontal flanges of track 40 on either side thereof, so that, when a carriage 3% comes to rest at the unit elevator, the roller 32 on the carriage rests upon flipper 49. The unit elevator may then be lowered by operation of its motor 57 to move the carriage down, until its lower roller 29 rests upon the block 35st the lower end or" its track. The unit elevator then continues downward through a short over-travel. As the flipper 49 nears the point, at which the lower roller 29 on the carriage seats on block 35, the flipper engages the upper end of a rod 62 supported on the machine frame for vertical movement by a bracket 63 and normally urged to upper position by a spring 64 encircling the rod. In the downward overtravel of the flipper, it moves rod 62 down to compress spring s4 and is then swung on its pivots by the rod, as shown in Fig. 7, so that it passes out from beneath roller 32. Thereafter, when the unit elevator rises, the flipper in its tilted posi: tion moves along with the rod, which is raised by its spring, and the rod holds the flipper in such position that the outer edge of the flipper passes by roller 32, as shown in Fig. 7, and the carriage 30 remains in its lowered position.

At the last treatment position in tank 21, the elevator 34a is provided with a flipper 65 mounted on brackets 66 and of the same construction as flipper 33. The angle iron 33a of the elevator is cut away to terminate above the inner bracket 66 and the track 40 overlies the outer bracket 66. When the elevator is in its upper position, the flipper closes the gap between the lower flanges of angle iron 33a. and track 40. A bridge generally desi nated 67 is mounted at the gap and it includes a horizontal plate 68 mounted on a block 69, which is vertically movable on rods 79 attached to the machine frame and is urged to downward position by springs '71 encircling the rods. When the block 69 is in its lower position and the elevator 34:: is in its upper position, the plate 68 rests on top of the flipper 65. When a carriage 30, which is moved along tank 21 in lower position, reaches the last treatment station in the tank and is raised by the flipper on elevator 34a, the roller 32 on the carriage engages plate 68 and moves the plate and block upwardly to the dotted line positions shown in Fig. 2. When the conveyor then advances a step, the roller moves out from under plate 67 and upon angle iron 33a of elevator 34a, and plate 68 is then moved down by the action of springs 71. if a carriage is advanced along the track 4% to the last treatment position 'in tank 21, the roller 32 of the carriage comes to rest on top of plate 68 of the bridge and then moves off upon the flange of angle iron 33a of elevator 34a upon the next movement of the conveyor.

The machine can be employed in various ways, as, for example, it may be 'used in electroplating operations, in which the workpieces carried by the arms 31 are immersed successively in the baths in the pro-treatment tanks 20, after which certain arms are lowered to immerse their workpieces in the plating tank 21 at the first treatment position, while other arms are advanced along the track 46 and lowered to immerse their workpieces in tank 21 at a later treatment position. The arms with their workpieces undergoing plating are then advanced to the successive treatment positions in tank 21 and, at the last treatment position, are placed so that they will be raised by the next upward movement of main elevator 34a. Thereafter, the arms are lowered by elevator 34a to immerse their workpieces successively in the baths in the post-treatment tanks 22, until all operations are completed.

The cycle above described, which involves delayed set-down of selected workpieces in the plating tank, is carried out by means or a number of control switches, of which the switch 72 controlling the action of the solenoid S1 of by-pass 41 is mounted on the upper part of the machine frame adjacent the by-pass. The switch has an operating arm 73 with a roller, which is engageable by plates 74 adjustably mounted on flanges 75 on respective.

arms 31. When an arm 31 is not to be lowered at the first treatment position in tank 21, its plate 74 is adjusted to engage the roller on switch arm 73, so that switch 72 is closed to energize the solenoid S1 and lower the plate 42 of the lay-pass, before the arm reaches the by-pass. Each plate 74 on an arm 31 is sufliciently long to hold switch 72 closed and the solenoid energized until the roller 32 of the arm moves upon plate 42 of the bypass. When the main elevator 34 then goes down, the arm 31 is supported by the lay-pass, and, when the conveyor advances the next step, roller 32 moves along track 40 with the arm held in raised position.

Arms 31, which are not lowered at the first treatment position in tank 21, are advanced along the high fixed track 4!) to one of the unit elevators. A switch 76 18 mounted adjacent each unit elevator and the switch is operable by an arm 77 carrying a roller at its free end. As the arm 31 reaches the unit elevator, the plate 74 on the arm engages arm 77 and operates the switch, so that as the arm 31 comes to rest on the flipper 49 of the elevator, the switch 76 is closed and the elevator moves down. The downward movement of the elevator is halted by opening of switch so by movement of its operating arm 78 by lug 59 on chain 54.

j the conveyor.

upward movement of the elevator is arrested by switch 61 having an arm 83 operable by lug 59 on chain 54.

In some instances, it may be desirable to set down certain of the workpieces at one intermediate treatment position of tank 21 and others at later treatment positions. For this purpose, a unit elevator is provided at each treatment position of tank 2 where workpieces are to be lowered, and each such unit elevator is operated by switches corresponding to those designated 69, 61, 76, and 79. The operating arms of the switches of different unit elevators to be engaged by plates and ears on arms 1% are mounted in different positions in relation to the ma chine frame and arms 31 are provided with plates and ears in proper position for operating the switches of selected unit elevators.

The machine may be operated with early pick-up of selected workpiece carrier arms and, for this purpose, the by-pass 41 is put out of action, so that the plate 42 there of remains in raised position, and each carrier arm 31 is lowered at the first treatment position of tank 23.. A unit elevator is provided at each treatment position of tank 21, where workpieces are to be removed from the tank, and, as an arm 31 reaches the position where it is to be raised, a plate on the arm similar to plate 7d closes a switch corresponding to switch 79 as the arm comes to rest on the flipper of the unit elevator. Closing of the switch causes the elevator to rise until its flipper is in alignment with track and, upon the next movement of the conveyor, the carrier arm rolls upon the track. As the arm moves away from the unit elevator, it operates a switch similar to switch 79 to cause the elevator to move down into position to receive the next workpiece carrier arm.

The wiring diagram shown in Fig. 8 shows the switch 72 connected in circuit with solenoid S1 between power lines L1 and L2 and, upon closure of the switch by a plate 7d on a carrier arm, the solenoid is energized and continues so, until the plate 74 passes by the switchoperating arm. Switch 76 is in circuit across the lines with a contactor coil 83 and, upon closing of the switch, the coil operates blade 33:: to establish a holding circuit for the coil through normally closed switch 6t). Energization ot' coil 83 also causes a second blade 33b to establish a circuit, which causes motor 57 to be connected across lines Li and L2, so that the motor will run in a desired direction, for example, to lower the unit elevator. When switch opened by lug 59 on chain 54., the holding circuit through blade 83a and the motor circuit through blade 83/; of the contact (re opened and the motor stops. Switch '79 is in a circuit across lines L1 and L2 with a contactor coil 34 and the coil, when energized, operates a blade E4 establishing a holding cir-- cuit for the coil and a second blade iidb establishing a circuit causing motor 57 to operate to raise the unit elevator. The holding circuit includes switch 61 operable by lug 59 on the unit elevator: chain to open the circuit.

The unit elevators of the machine may be operated hydraulically, if desired, by the apparatus diagrammatically illustrated in Figs. 9 and 10. in the installation shown, the elevator comprises a flipper 4? attached to a block St? movable on guide rods 52, the flipper engaging the roller 32 on a carriage 36 having the workpiece supporting arm 31. The block and flipper are movable by a connecting rod 86 movable by a piston in a cylinder 37, which is supplied with fluid from a tank 88 by a pump 89. The discharge from the pump travels to a four-way valve 9%, the gate element of which has a shaft carrying a sector 91 having teeth engageable by a rack 92 connected to the plunger of solenoid 93. A spring (not shown) acts on the solenoid and normally holds the gate element of the valve in the position shown, in which the pump discharge travels through a line 94 to the valve and is returned by

lines

95 and 96 to tank 88. At the same time, the valve connects the hue 97 leading to the cylinder 37 to iii (all

line 98, which is connected to line 96 leading to tank 38. When solenoid 93 is energized, the gate element of valve 90 is moved through 90, so that the pump discharge 94 is connected through line 97 to cause the piston and unit elevator to rise. When the solenoid is de-energizcd, the gate element returns to the position illustrated and the fluid within the cylinder escapes at a controlled rate through a choke valve 99 in line 97. A check valve 100 in a bypass around the choke valve permits the fluid to enter the cylinder from the pump without restriction but prevents return flow. Line fill contains a check valve 101 permitting fiow only toward the pump.

In an installation of the hydraulic type for early pickup or" workpieces, for example, the solenoid 93 is operated by a switch corresponding to switch 76 but located in position to be engaged by an arm moving in lowered position along tank 2;. and approaching the unit elevator. The lowering of the elevator is brought about by deenergiring solenoid 93 by means of another switch corresponding to switch 7) and operable by an arm 31 leaving the unit elevator in upper position and moving along track so. When the hydraulically-operated elevator is employed for delayed set-down of workpiece carrier arms, appropriate changes are made in the location and operation of the switches.

in the operation of the machine described, each carrier arm receives its load of workpieces at a loading station and the operator at that station sets the triggers on the arm, namely, the plate 74 and the car 81, so that the triggers will actuate or miss switches 72-, 76, and 79, as may be desired. The loaded carrier arms are advanced stepwise by the conveyor during the periods when the main elevators are raised and, when the arms have been lowered to immerse the workpieces in the plating tank, the arms are not engageable by the main elevators and, accordingly, remain in their lowered positions until they reach the last treatment position in the tank, unless early pick-up is desired. When an arm has been raised from the plating tank by a unit elevator at an intermediate treatment position of the tank, it continues along the fixed track it to the post-treatment stations where it moves upon the second main elevator. The movements of the main elevators and conveyors are necessarily synchronized, but the unit elevators may be operated independently of the main elevators and their movements need not be restricted to periods when the conveyor is at rest.

in the machine described, the triggers are mounted on the workpiece carrier arms and switch 72 controlling the solenoid of by-pass 41 is located close to the by-pass, while switches 76 and 7% for lowering and raising the unit elevator are placed close to that elevator. It is apparent that the triggers need not be mounted on the arms or on the conveyor and the switches need not be placed close to the parts, which they control. Instead, a movable support, such as the rotary drum 102, may be placed close to the station where the arms are loaded with workpieces and the support may be provided with triggers in the form of pins 133, which can be set in outer and effective or inner and ineffective positions on the support. The support has as many angularly spaced positions for pins as there are arms on the conveyor and the support is connected to the conveyor drive through a chain 3.84, so that it is advanced stepwise with the a conveyor and makes one complete rotation for each circuit of the conveyor.

Switches 2, 7d, and 79 are disposed about the periplery of support 102 and perform the same functions as switches '72, '76, and 79. Also, the positions of

switches

72, 76, and 79 relative to support 102 are the same as the positions of

switches

72,, 76, and 79 in relation to the conveyor. The switches could be placed so as to be operated by pins in a single row on the support, but, by placing the switches in upper and lower levels and providing two pins at each station on the support, the support may be made small in diameter and interference between switches is avoided.

In the use of the modified control device shown, the workman at the loading station adjusts the pins on support 1&2 for each carrier arm loaded, so that the carrier arm will enter the plating tank and be removed it from at the desired points. If the workpieces on an arm are to receive a full plating, the pins on the support 102, which correspond to that arm are pushed inward to ineffective position. if the workpieces on a carrier arm are to be given a delayed set-down, for example, the pins on the support corresponding to the arm are moved to effective position so as to operate switches 72-, 75, and 79" as previously explained in connection with

switches

72, 76, and '79. When the machine includes more than one unit elevator, support is provided with additional sets of pins, so that each arm on the conveyor can be raised or lowered by any desired unit elevator. When early pick-up of carrier arms is desired, switches are provided adjacent support M2 for operating the unit elevator at the early pick-up station.

I claim:

1. In a processing machine, a conveyor for conveying a work member horizontally, a pair of main elevators for moving the work member vertically relatively to the conveyor at locations spaced along the path of travel of the conveyor, means separate from said main elevators for moving said work member vertically independently of the main elevators, and means movable with said work member for controlling said moving means.

2. In a processing machine, a conveyor for conveying work members horizontally step by step along a plurality of work stations, an elevator for moving said work members vertically into and out of working position relatively to the conveyor, means for driving the conveyor and elevator in a predetermined and repetitive cycle, separate means at at least some of said stations operable when energized for moving said work members vertically relatively to said conveyor at said stations independently of each other and also independently of the elevator, and means movable with said work members and operable for controlling the cnergization of said last mentioned means upon movement of the work members by the conveyor into said some of the stations whereby said work members will control the cycle of operations through which they are carried by said machine.

3. In a processing machine having an intermittently operable conveyor with a workpiece supporting arm vertically rcciprocable thereon, a lif -out member positioned to engage the arm in one of its conveyed positions, a motor to drive the member to elevate the arm and to hold the arm up until the conveyor operates, means for receiving the arm to hold it up after the conveyor moves it oil the member, and means for driving the motor to again lower the member.

4. In a processing machine having an intermittently operable conveyor with a workpiece supporting arm vertically reciprocable thereon, a littout member positioned to engage the arm in one of its conveyed positions, a motor operable to drive the member to elevate the arm and to hold the arm up until the conveyor operates, means adjustably carried by the arm for making said motor selectively effective or ineffective, means operable after the motor has been made effective to lift the arm for receiving the arm to hold it up after the conveyor moves it off the member, and means responsive to movement of the arm off the member for driving the motor to again lower the member.

5. In processing machine having a plurality of pretreatment stations, a treatment station having a plurality of treatment positions, and a plurality of post-treatment stations, a conveyor extending along the stations, a plurality of workpiece carrier arms movable horizontally in fixed spaced relation by the conveyor, means for raising and lowering groups of the arms relatively to the conveyor at the pretreatment and post-treatment stations, said means including main elevators extending along the pie-treatment and post-treatment stations, respectively, a. fixed track extending along the treatment station at the level of the main elevators in upper position, a unit elevator for individual carrier arms at an intermediate position of the treatment station adjacent an end of the track and movable between the level of the track and the level of the lowered main elevators, means for operating the unit elevator, and control means for the operating means actuated in timed relation to the movement of said arms by the conveyor.

6. In a processing machine having a plurality of pretreatment stations, a treatment station having a plurality of treatment positions, and a plurality of post-treatment stations, a conveyor extending along the stations, 21 plurality of workpiece carrier arms mounted in spaced relation on the conveyor and movable between upper and lower positions, means for raising and lowering groups of the arms on the conveyor at the pro-treatment and post-treatment stations, said means including main elevators extending along the pro-treatment and post-treatment stations, respectively, a fixed track extending along the treatment station at the level of the main elevators in upper position, a unit elevator for individual carrier arms at an intermediate position of the treatment station adjacent an end of the track and movable between the level of the track and the level of the lowered main elevators, means for operating the unit elevator, and control means for the operating means actuated in timed relation to the movement of the carrier arms by the conveyor.

7. In a processing machine having a plurality of pretreatment stations, a treatment station having a plurality of treatment positions, and a plurality of post-treatment stations, a conveyor extending along the stations, a plurality of workpiece carrier arms mounted in spaced relation on the conveyor and movable between upper and lower position main elevator extendin along the pretreatment stations for raising and lowering groups of the arms on the conveyor, the elevator having means for lowering individual at the first treatment position of the treatment station and leaving said arms lowered at said position, a second main elevator cxtendim along the post-treatment station for raising and lowering groups of the arms on the conveyor, the second elevator having means for raising individual arms at the last treatment position of the treatment station, a fixed track extending along the treatment station at the level of the elevators in upper position, a unit elevator for individual carrier arms at an intermediate position of the treatment station adjacent an end of the track and movable between the level of the track and the level of the lowered main ele vators, means for operating the unit elevator, and control means for the operating means actuated in timed relation to the movement of the carrier arms by the conveyor.

8. in a processing machine having a plurality of pre treatment stations, 2. treatment station having a plurality of treatment positions, and a plurality of post-treatment stations, a conveyor extending along the stations, a plurality of workpiece carrier arms mounted spaced relation on the conveyor and movable between upper and lower positions, a main elevator extending along the pretreatment stations for raising and lowering groups of the arms on the conveyor, the elevator having flipper means for lowering individual arms at the first treatment position of the treatment station and leaving said arms lowered at said position, a second main elevator extending along the post-treatment station for raising and lowering groups of the arms on the conveyor, the second elevator having flipper means for raising individual arms at the last treatment position of the treatment station, a fixed track extending along the treatment station at the level of the elevators in upper position, a unit elevator for individual carrier arms at an intermediate position of the treatment station adjacent an end of the track and movable between the level of the track and the level of the lowered main elevators, means for operating the unit elevator, and control means for the operating means actuated in timed relation to the movement of the carrier arms by the conveyor.

9. in a processing machine having a plurality of pretreatment stations, a treatment station having a plurality of treatment positions, and a plurality of post-treatment stations, a conveyor extending along the stations, a plurality of workpiece carrier arms mounted in spaced relation on the conveyor and movable between upper and lower positions, a main elevator extending from the first pre-treatment station to the first treatment position in the treatment station, a second main elevator extending from the last treatment position of the treatment station to the last post-treatment station, the elevators operating to raise and lower groups of the arms on the conveyor, a fixed track extending between the elevators at the level of their upper positions, the track having a gap at an intermediate treatment position, a unit elevator for individual carrier arms disposed opposite the gap in said track and movable between the level of the track and the level of the lowered main elevators, means for operating the unit elevator, control means for the operating means actuated by the carrier arms, and a by-pass operable by carrier arms approaching it to connect the first main elevator in raised position to the fixed track.

10. In a processing machine having a plurality of pretreatment stations, a treatment station having a plurality of treatment positions, and a plurality of posttreatment stations, a conveyor extending along the stations, a plurality of workpiece carrier arms mounted in spaced relation on the conveyor and movable between upper and lower positions, a main elevator extending from the first pre-treatment station to the first treatment position in the treatment station, a second main elevator extending from the last treatment position of the treatment station to the last post-treatment station, the elevators operating to raise and lower groups of the arms on the conveyor, a fixed track extending between the elevators at the level of their upper positions, the track having a gap at an intermediate treatment position, a unit elevator for individual carrier arms disposed opposite the gap in said track and movable between the level of the track and the level of the lowered main elevators, means for operating the unit elevator, control means for the operating means actuated by the carrier arms, a bypass operable by carrier arms approaching it to connect the first main elevator in raised position to the fixed track, and a bridge for connecting the track to the second main elevator in raised position.

11. In a processing machine having a plurality of pre treatment stations, at treatment station having a plurality of treatment positions, and a plurality of post-treatment stations, a conveyor extending along the stations, a plurality of workpiece carrier arms mounted in spaced relation on the conveyor and movable between upper and lower positions, a main elevator extending from the first pre-treatment station to the first treatment position in the treatment station, a second main elevator extending from the last treatment position of the treatment station to the last post-treatment station, the elevators operating to raise and lower groups of the arms on the conveyor, a fixed track extending between the elevators at the level of their upper positions, the track having a gap at an in termediate treatment position, a unit elevator for individual carrier arms disposed opposite the gap in said track and movable between the level of the track and the level of the lowered main elevators, means for operating the unit elevator, a bypass operable to connect the first main elevator in raised position to the fixed track, and control means for the tmit elevator operating means and the bypass, said control means being actuated in timed relation to the movement of the carrier arms by the conveyor.

12. In a processing machine, a conveyor for conveying a work member horizontally, a pair of main elevators for moving the work member vertically relatively to the conveyor at locations spaced along the path of travel of the conveyor, means between and separate from the main elevators for moving the work member vertically independently of the main elevators, and selectively operable means movable with the work member for controlling the moving means.

References Cited in the file of this patent UNITED STATES PATENTS 2,048,938 Larson et a1. July 28, 1936