US3192796A - Memory system for spray coating machines or the like - Google Patents

Description

y 1965 1:..1. PEEPS ETAL 3,192,796

MEMORY SYSTEM FOR SPRAY COATING MACHINES OR THE LIKE Filed Feb. 12, 1960 s Sheets-Sheet 1 COAT m c, MATER] AL uvmvron- DONALD J. PEEPs BY FRANCIS W-HOFFMAN MEMORY SYSTEM FOR SPRAY COATING MACHINES OR THE LIKE Filed Feb. 12, 1950 July 965 D. J. PEEPS ETAL 3 Sheets-Sheet 2 I LIGHTISOURCE @MPUT lNPUT V NO \NPUT AIR CONTROL SPRAY N0 SPRA I uvmvrm Domxu: J. PEEPS BY FRANCIS W. HOFFMAN MX y ATTORNEYS July 6, 1965 1:..1. PEEPS ETAL 3,

MEMORY SYSTEM FOR SPRAY COATING MACHINES OR THE LIKE Filed Feb. 12, 1960 3 Sheets-Sheet;

INVENTOR. DONALD J- PEEPs BY FRANCIS W. HOFFMAN ATToEuEys United States Patent 3,192,796 MEMGKY SYSTEM: FGR SEEAY QOATING MAfiHINES GR THE LIKE} Donald J. Peeps, Rossftord, and Francis W. Hofinran, Toledo, Ohio, assignors to The De Vilbiss Company, Toledo, @hio, a corporation of @hio Fiied Feb. 12, 196i Ser. No. 8,2% 1 Qlaian. (Ci.-74-568) This invention relates to a control for a spray coating device or the like, and is particularly directed to a so-called memory device by which information concerning the size, extent or outline of an object to be coated is stored and later used to actuate a spray coating device or other apparatus for performing an operation on a work piece. In this way, unnecessary operation is avoided and spraying is done only when a portion of the object is in place to receive a coating.

Memory devices for the actuation of spray coating ma chines are known in the art, but for the most part these known units are characterized by an inability to store sufficient information for satisfactorily precise control of an operation with respect to a work piece profile, particularly where the work piece is of extended length. Such known devices therefore are inadequate for the operation of a reciprocating spray coating machine used to coat successive objects having very great longitudinal dimensions and irregular outlines or interruptions in their surface from side to side.

The primary object of the present invention is to provide a control for a spray coating machine which is capable of storing a greater quantity of information and of feeding the stored information to the spray gun actuating devices at a precise, though adjustable, later time.

Other objects and advantages of the invention will become apparent from a detailed description of a preferred embodiment thereof, reference being had to the accompanying drawings, in which:

FIG; 1 is a somewhat diagrammatic, side elevational view of a machine embodying the present invention, with a conveyor and work thereon shown in perspective;

FIG. 2 is a viewtaken on line 2-2 of FIG. 1 and diagrammatically showing a sensing unit of the machine;

FIG. 3 is a view taken on line 3-3 of FIG. 1 and diagrammatically showing a spray coating unit of the machine;

FIG. 4 is a greatly enlarged elevational view taken on line 4-4 of FIG. 1;

FIGS. 5 and 6 are greatly enlarged views taken respectively on lines 5-5 and 66 in PEG. 1; and

FIG. 7 is a detailed sideview taken on-line 77 of FIG. 5.

Referring to the drawings, and particularly to FIG. 1, the present invention is shown in conjunction with a spray coating machine comprising an endless conveyor it having a driving sheave l2 driven by a conveyor motor 14 and an idleror return sheave 16. Objects to be spray coated can be placed on the'conveyor manually or mechanically and removed after coating in any suitable manner.

The spray coating device itself is a known reciprocating type which includes one or more spray heads 18 (FIGS. 1 and 3) supported on acarriage 2t) and moved back and forth across the conveyer by a conventional any suitable valve means may be used to actuate the spray heads.

An object contour sensing device such as a photocell d4 (FIGS. 1 and 2) is caused to scan across the conveyor 11'1 timed relation to or in synchronism with the spray heads 18. For this purpose the photocell 34 is mounted on a carriage 36 which is reciprocated by a chain drive 38 and a Scotch yoke 40 driven directly or indirectly from the motor 26 (FIG. 1) which drives the spray head carriage 2d. The photocell 34 is preferably connected so that its amplified signal causes a circuit to open when the cell does not receive light, and to close when the cell is energized from a suitable light source 42 beneath the conveyor. Any suitable circuit-controlling mechanism may be used in place of the photocell 34, but the signal should preferably be produced by a unit which does not rely on physical contact with the work. By way of example, a bounce light system can be used with a photocell t-o reflect light from the work or a magnetic proximity sensing device can be used with metal work.

I The signal from the sensing unit is increased by an amplifier 44 and is transmitted to the memory device With which the present invention is principally concerned.

The memory device, indicated by the numeral 46 in FIG. 1, includes a housing 48 containing an endless chain 59 which can be of almost unlimited length, if desired. While a chain is preferred, other elongate, fiexible elements can be used which have dimensional stability in the direction of their length, such as timing belts or metal belts, by way of example. The chain St) is guided in a circuitous path by idler sprockets 52 and is driven by a drive sprocket 54, which sprockets are rotatably mounted on a wall of the housing 48. The sprocket 54 is driven by the conveyor motor 14 through any suitable timestable means, such as a chain and sprocket assembly in icated at 56. The progression of the chain is thus a precise function of the progression of the conveyor.

The chain 50,. as shown in more detail in FIGS. 4-7, includes generally T-shaped links 58 connected by link pins 6t with shank portions 62 of the links 58 being drilled to receive holding bodies or cylinders 64 and 66 which are identical except for length, the cylinders 64 being longer for outer pairs of the links 58 and the cylinder 65 being shorter for inner pairs of the links 58. One end of each of the cylinders 64 and 66 is provided with a collar 65 and the other end is grooved to receive locking rings 70 to prevent lateral movement of the cylinders 64 and 66 with respect to the links 58. The cylinders 64,:and 66, which are magnetized, carry rigid memory members or pins 72 of suitable magnetic material, the pins 72 having a suitably free sliding fit in the cylinders. With this arrangement, the pins '72 are held in any given position by the magnetic field, yet can be moved longitudinally of the cylinders 64 and 66 by the application of relatively small force.

The pins 72 can be moved to one side, as shown in FIG. 4, by suitable moving means such as a roller 74 which is mounted on a yoke 76 and attached to a magnetic core 78. The core 73 rides in the center of a coil 79 in a housing 8% and moves in and out of the coil in a known manner when current is supplied thereto from the amplifier 44 through leads 82 and $4. In this particular instance, current is supplied to the coil 79 when the sensing device 34 is not over an object to be coated, the current causing the core 73 to draw into the coil and to move the roller 74 away from the pins 72. When the sensing device 34 is over a work piece, so that it receives no light from the source 42, the circuit is opened and no current is supplied to the coil 79 whereby the core 78 is pushed outwardly by a spring 85 and causes the roller '74 to push the pins 72 toward the left, as shown in FIG. 4.

The roller 74 can be driven at a peripheral speed equal to the lineal speed of the pins '72 to prevent possibility of the pins being bent as they are pushed longitudinally with respect to the cylinders 64 and 66. This can be accomplished by means of a flexible shaft 88 (FIG. 1) having a square end (not shown) which fits into a square hole 90 (FIG. 4) of an axle 92 of the roller 74. The flexible shaft 88 is driven by a pair of beveled gears 94, 96 (FIG. 1) which are driven by the conveyor motor 14 through part of the chain and sprocket assembly 56 and a chain and sprocket assembly 98 associated therewith. The sprockets and gears are chosen so that the peripheral speed of the roller 74 will equal the lineal speed of the pins 72.

After the pins 72 pass the roller 74, they travel with the chain 50 over the circuitous path and pass a feeler switch 100 which controls the supply of coating material and air to the spray heads 18. The switch 100 has a spring-loaded arm 102 which is normally positioned in the path of the pins 72, keeping the switch opened, but which moves toward the right (in FIG. 1) when contacted by the pins 72 which have been displaced by the roller 74, thereby closing the switch. When the switch 100 is closed, it opens a normally-closed solenoid valve 103 associated with the air-operated valve 32, supplying air to the latter valve to cause it to open and to supply air and coating material from the lines 30 and 28 to the spray heads 18. Of course, the length of the chain 50 and the ratio of the speed of the chain 50 to the conveyor belt are predetermined so that the position of the sensing device 34 with respect to the work, when the pins 72 are at the roller '74, corresponds to the position of the spray heads 18 with respect to the same piece of work, when the same pins 72 have moved to the feeler switch 100.

Before the pins 72 against reach the roller 74, any displaced pins are returne-d to their original positions by means of a wiper plate 104 which is located in alignment with the pins 72 and has a tapered leading surface which the pins 72 contact as they move by it. The pins are thus in a position to be displaced again by the roller 74 in response to a displacing action caused by another work piece.

With the length of the chain 50 provided between the roller 74 and the switch 100, additional operating apparatus can be used between the Sensing device 34 and the spray nozzles 18, which apparatus can be operated by additional feeler switches or the like located along the path of the chain 50 at appropriate places between the roller 74 and the switch 100. Thus, the chain 50 can be employed to control additional operations or other operations beside coating for the work on the conveyor. For example, welding or riveting machines or apparatus can be employed to fasten two sheets of metal together.

The long chain also enables the sensing device 34 and the spray heads 18 to be spaced far apart. However, even if the sensing device 34 and the spray nozzles 18 are close together, so that a short chain or even a wheel carrying the pins '72 could be used, the use of a long chain enables it to be driven rapidly compared to the lineal speed of the belt 10 so that the spray heads 18 move only a short distance across the work for each of he pins 72. This enables much closer control of the spray heads 18 than would otherwise be possible.

To review the operation, when the sensing device 34 receives light from the source 42 because no work is interposed between the two, the device 34 causes current to flow in the amplifier 44 which actuates the coil 79 and moves the roller 74 away from the chain 50. The pins 72 then will not contact the arm 102 which will keep the switch 100 open and prevent flow of coating material to the spray heads 18. When the device 34 does not receive light, it deactivates the coil 79 and enables the spring 86 to move the roller 74 toward the chain 50 and displace some of the pins 72. When those pins 72 which are displaced reach the feeler switch arm 102, they strike this arm and cause the switch 100 to close. The solenoid valve 103 then supplies air to the air-operated valve 32 which opens and supplies air and coating material to the spray heads 18. This method of operation is particularly advantageous because coating material will be supplied to the spray heads 18 even it electrical failure should occur in the sensing device 34, the source 42, or the ampliiier 44. However, many modifications of the manner in which the various components operate are possible, the only important thing being that air and coating ma terial are supplied to the spray heads 18 when work is interposed between the sensing device 34 and the light source 42, and vice versa.

Numerous modifications of the above described embodiment of the invention will be apparent to those reading the above specification and viewing the accompanying drawings. It is to be understood that such modifications can be employed without departing from the scope of the invention it within the spirit and tenor of the accompanying claim.

We claim:

A memory device for controlling coating of a plurality of workpieces carried by a conveyor, said memory device comprising a single endless chain having a plurality of links, a plurality of pin-holding bodies carried by said links transversely to the longitudinal extent of said chain, said bodies having passages extending longitudinally therethrough, a memory pin carried by each of said bodies and protruding from opposite ends of said bodies beyond said links, said memory pins being slidably received in said passages for longitudinal movement with respect thereto, one of said pins and said bodies being magnetized and the other of said pins and said bodies being of magnetic material whereby said pins are fixedly held in said passages in any attained position, means supporting and guiding said chain over a predetermined tortuous path, means for driving said chain at a predetermined lineal speed, means adjacent a portion of said path for displacing said memory pins in said pin-holding bodies to predetermined positions in said passages, and means adjacent said path for returning the displaced memory pins to their first positions. 7

References Cited by the Examiner UNITED STATES PATENTS 736,700 8/03 Cyr 74-568 XR 1,868,894 7/32 Glahn 2141l 2,547,884 4/51 Paasche 118-2 2,565,655 8/51 Giraudo 118-314 2,675,778 4/54 Peeps 118-2 2,690,800 10/54 Ross 74-568 XR 2,754,795 7/56 Enssle 118-2 2,767,788 10/56 Parker -568 XR 2,866,176 12/58 Durfee et al. 340-173 2,867,789 1/59 MacNeill et al 340-173 2,949,674 8/60 Wexler 317-159 3,100,040 8/63 Kleist 198-38 FOREIGN PATENTS 8,450 5/11 Great Britain. of 1910 BROUGHTON G. DURHAM, Primary Examiner.

JOSEPH B. SPENCER, RICHARD D. NEVINS,

' Examiners.

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