US2930078A

US2930078A - Caul board separator

Info

Publication number: US2930078A
Application number: US586694A
Authority: US
Inventors: Harry A Raddin; Donald L Johnson
Original assignee: Miller Hofft Inc
Current assignee: Miller Hofft Inc
Priority date: 1956-05-23
Filing date: 1956-05-23
Publication date: 1960-03-29
Anticipated expiration: 1977-03-29

Description

March 29, 1960 H. A. RADDIN ETAL 2,930,078

CAUL BOARD SEPARATOR Filed May 25, 1956 4 Sheets-Sheet 1 @LSE) LSI IN VEN TORJ' HARRY A RADDIN DONALD L.JOHNSON March 29, 1960 H. A. RADDIN ET AL CAUL BOARD SEPARATOR Filed May 23, 1955 4 Sheets-Sheet 2 FIG. 2

INVENTORS HARRY A. RADDIN DONALD L. JOHN SON ATfOR V March 29, 1960 H. A. RADDIN ETAL 2,930,078

CAUL BOARD SEPARATOR Filed May 23, 1956 4 Sheets-Sheet 3 FIG.3

/ INVEN TOR.

- I HARRY A- RADDIN By DONALD L.JOHNSON A T TORNEVS March 29, 1960 RADDlN ETAL 2,930,078

CAUL BOARD SEPARATOB 4 Sheets-Sheet 4 Filed May 23, 1956 HU EImQQ m m mm 3i n50 IN VEN TORS HARRY A. RADDIN BY DONALD L.JOHNSON fla 2,930,078 Patented Mar- 29,1960:

CAUL BOARD SEPARATOR Harry A. Raddin, Richmond, Va., and Donald L. Johnson,

Tacoma, Wash., assignors, by direct and mesne assignments, to Miller Hoift, Inc., Richmond, Va., a corporation of Delaware Application May 23, 1956, Serial No. 586,694

3 Claims. (Cl. 18-2) It is an object of this invention to provide apparatus for removing boards molded from, a mixture .of wood chips and resin from the trays or cauls in'which such boards are molded.

is a further object of this invention to provide in an apparatus as aforesaid a system of controls for automatic operation whereby the apparatus is adapted to cooperate. with other machine elements in the manufacture of such boards.

The above and other objects will be made clear with the following detailed description taken in connection with the annexed drawings in which:

l is a plan view of the improved apparatus;

Fig. 2 is a section on the line 2-2 of Fig. 1;

Fig'. 3 is a side elevation of the improved apparatust.

4 is a detailed view of certain elements of the apparatus; and

Figs. 5A, 5B and 5C are wiring diagrams of the control circuits.

There is a rapidly growing interest in manufacture of boards from waste wood products suitably reduced to Chips or particles which are mixed with a thermosetting binder'pressed to the desired caliper and heated sufficiently to set the resin and thus to bind the chips together into a strong, rigid board. For various commercial reasons, such boards are produced in an ultimate panel size of 4 by 8 feet. andin thicknesses from as little as A inch to as much as 1 /2 inches. 'The boards" are formed by depositing a loose layer of chips into a series of cauls which are then inserted into a multiple platen press which operforms the heating and pressing steps above referred to.

Obviously, the loaded cauls must remain in the press for a substantial time in order effectually to cure the thermosetting binder throughout the cross-section of the board, the precise time depending on the nature of the resin and the caliper of the board. Until quite recently, this substantial curing time was considered to limit the manufacture of these boards to a batch type of process. All of the other steps in the manufacture of the board were susceptible of continuous consecutive operation. There have been devised automatic mechanisms for loading and unloading a multiple platen press and these. are designed to receive consecutive boards until a press load has been attained and then to deliver to or remove from the press a full charge of boards. The unloading mechanism delivers boards consecutively in the same manner in which the loading mechanism receives boards.

The present invention is concerned with apparatus which receives consecutive loaded cauls from the press unloading mechanism, separates the board from the caul and delivers the empty caul for refilling.

The wiring diagrams of Figs. 5A, 5B and 5C carry NEMA symbols based on Industrial Control ICI23.5 October 1951.

Referring now to Figs. 1, 2 and 3, there is shown a pair of ejector belts 10 supported by table rolls 12. Loaded cauls are delivered to the belts 10 by a ram forming part of the press unloading mechanism. As will be described in detail hereinafter, delivery of the caul to the belts 10 starts the belts traveling in the direction of the arrow 14 shown in Fig. 1. The belts are auto. matically stopped when the caul reaches a predetermined position.

When the belts stop, vacuum is applied through line 16 to a pair of diaphragms 18. Diaphragms 18 raise a pair of suction cups 20 into contact with the bottom'of, a tray 24 resting on the belts 10. When the cups 20 come in contact with the bottom of the tray 24, vacuum is applied through a line 26 to the interior of the cups 20, thus gripping cups 20 firmly to the bottom of the tray 24. With the cups thus firmly in engagement, vacuum is applied through the line 28 to another pair of diaphragms 30. The diaphragms 30 over-ride to a degree the lifting action of the diaphragms 18, thereby exerting a downward pull on the suction cups 20 and thereby upon the trays 24.

The attainment of a predetermined vacuum in the diaphragms 30 operates a conventional four way valve (not shown) to deliver pressure or vacuum as the case may be, to a cylinder'36. A piston within the cylinder 36 is connected to a rod 38 which is pivoted to a rocka ble lever 40. The cylinder 36 is itself pivoted to the machine frame at 42 and is fed or exhausted through lines 44 and 46. The lever is keyed at one end to a shaft 48 rotatable in bearings 50 secured to the machine frame. Also keyed to the shaft 48 and adjacent each of its ends are a pair of levers 52, the free ends of which are pivoted to links 54. Each of the links 54 is pivotally secured to a shaft 56. Each end of the shaft 56 is rigid ly secured to a shaft 58. Each of the shafts 58 is slidably mounted in bearings 60 secured to the machine frame. A plate 62 is rigidly secured to the front end of each of the shafts 58. A pusher plate 64 abuts on the plate 62 and is secured there by a holding plate 66. By forming On the opposite side of the machine is a lower feed roll 70 and 'an upper feed roll 72. The upper feed roll 72 is spring loaded and vertically adjustable. When thepiston rod 38 moves forward, it rocks the shaft 48 by means of the lever 40. This in turn rocks the levers 52 v which by means of the links 54, draws forward the shaft; 56, draws forward the shaft 58 and brings the pusher plates 64 into contact with a board 74 resting in the caul 24. The board 54 is thrust into the grip of the. constantly rotating

rolls

70 and 72 and is fed clear of the machine while the caul or tray 24 is held by the vacuum cups 20. There are two alternative structures for removing the empty caul from the machine. One of these, as shown in Fig. 4, is to use a constantly running chain carrying a series of hooks 82 which engage with loops 84 formed at the leading end of each tray. This has the advantage of providing positive and accurate placement of the trays but as will appear hereinafter, this arrangement adds some complication to the controls. The alternative (not shown) is simply to provide conveyer belts and deliver the empty trays by operation of the ejector belts 10.

The control system will now be described with particular reference to Figs. 5A, 5B and 5C. A loaded caul is thrust onto the belts 10 by the press unloading mechanism and depresses first LS29 and then LS-30. These are limit switches which condition the press unloading mechanism for its next operation. Details of the circuits involved in LS29 and LS-30 form no part of this invention. Initially, the belts 10 were started by pushing either of the start buttons shown in Fig. 5B. As the caul proceeds, it depresses a limit switch LS 2 which energize a contact relay CR-l. This stops the ejector belt and energizes a timed delay relay TD-2. TD2,

after a delay of one or two seconds, energizes solenoid 1. Solenoid 1 operates a valve to apply vacuum to the diaphragms 18 whereby to raise vacuum cups 20. The TD-2 interlock shown in Fig. A is a holding circuit to keep things going even if LS-2 should be released because of lifting of the caul by the vacuum cups 20.

When the vacuum in diaphragms 18 reaches a predetermined value, a pressure switch VS--1 closes to energize a solenoid 2 which operates a valve to apply vacuum to the cups 20 through the line 26 and also to apply vacuum to diaphragms 30 through the line 28.

When the vacuum in the cups 20 and the diaphragms 30 reaches a predetermined value, a pressure switch VS-2 closes, energizing a solenoid 3. The solenoid 3 operates a four way valve to actuate the cylinder 36 and its associated linkage. When the lever 40 reaches its forwardmost position, it closes a limit switch LS-5 which energizes a relay CR2. Energization of CR2 breaks the circuits of

solenoid

1, 2 and 3, which has the efiect of releasing the empty caul from the grip of the suction cups 20.

When the chain 80, shown in Fig. 4, is in use, the timing is such that the lug 84 will be engaged by hook 82 and the empty caul will be drawn out of the machine. In passing, the empty caul will close limit switches LS-l and LS-3. Limit switch LS-3 starts the ejector belts 10, while LS-l energizes the time delay relay TD-1. After a short time delay, TD1 starts the press unloading mechanism previously preconditioned by LS29 and LS-30.

A limit switch LS4 is mounted on an arm 90 pivoted on the shaft 92 around which the belt 80 is driven and is adjustable to various positions. Each hook 82 will close LS-4 just before it comes into caulengaging position. It is as shown in Fig. 5A in the circuitof CR3. When LS-4 is closed by a hook 82, CR3 is energized, its four contacts are changed, three normally closed contacts open and one normally open contact closes. Closing of the one normally open contact holds the CR3 circuit closed even though the hook passes over to release LS-4. One of the normally closed contacts on opening, stops the caul-returned conveyer by deenergizing a coil C1, another stops the ejector beltby deenergizing a coil C2, both as shown in Fig. 5B. The third breaks the circuit to a coil M5, which shuts down the press unloading mechanism. LS4 will energize CR3 only if the feed line L-1 of Fig. 5A is open. The line L1 will be alive only when both the CR-1 and CR2 contacts are closed, a condition which, as above noted, exists only during the advance of the pusher plate 64. When the pusher plate closes LS 5 to energize CR2, the normally closed CR2 contact, Fig. 5A, opens and deenergizes the line L1. Therefore, if vacuum is on the cauls when LS-4 is closed the system will stop, if vacuum is not on the cauls the line L1 is dead and CR--3 will not energize when LS-4 is closed by the hook 82.

The adjustment quadrant 92 shown in Fig. 4 permits ssetting of the time lag between the time 15-4 is closed and the time the hook 82 reaches caul tab 84. This is to accommodate the ditferent time cycles occasioned by diiferent thicknesses of board.

If belts are used in place of the chain and books 82, such belts run continuously and are similar to belts 10. The empty caul in such case is delivered to the caulremoving conveyer by the ejector belts 10. For such operation, LS-S is eliminated and CR2 is used to start the ejector belt to deliver an empty caul to the empty caul conveyer.

While certain specific embodiments of this invention have been described herein, it is clear that as a matter of design there is room for considerable variation of detail. Accordingly, this invention is not to be limited to the precise details disclosed but only as set forth in the subjoined claims.

We claim:

1. Means to separate boards formed of a mixture of wood particles and resin, pressed and cured to rigid condition from the trays in which such boards were pressed and cured, said means comprising: a unidirectional conveyer for loaded trays; means to stop the progress of the trays on and with said conveyer; means to grip and hold the stopped tray; means to strip the board from the tray in a direction at right angles to the motion of the conveyer, and means responsive to the complete removal of a board from a tray to release said gripping and holding means for further progress of the empty tray on and with said conveyer.

2. Means as set forth in claim 1 including a limit switch operable by passage of an empty tray and a relay responsive to said switch for restoring the apparatus to its original position.

3. Means as set forth in claim 1 including a hook bearing conveyer, the hooks of said conveyer being spaced to engage loops on each empty tray; and a limit switch in the path of said hooks, said limit switch operating to disable the apparatus if said gripping and holding means are still active.

References Cited in the file of this patent UNITED STATES PATENTS 1,851,028 Worrall Mar. 29, 1932. 2,499,399 Lyon Mar. 7, 1950 2,619,681 Baker et a1. Dec. 2, 1952 2,625,284 Atwood Jan. 13, 1953 2,629,158 Molla Feb. 24, 1953 2,636,625 Pries Apr. 28,1953 2,642,782 Chapman June 23, 1953 2,704,608' Graf et-al Mar. 22, 1955 2,775,787 Krag Ian. 1, 1957