US3168863A - Selective inertia lumber marker - Google Patents

Description

Feb. 9, 1965 R. c. M RAE 3,163,353

SELECTIVE INERTIA LUMBER MARKER Filed Feb. 20. 1961 2 Sheets-Sheet 1 Roberf'CMcHae INVEN TOR.

ATH'y.

1965 R. c. MGRAE 3,168,63

SELECTIVE INERTIA LUMBER MARKER Filed Feb. 20. 1961 2 Sheets-Sheet 2 g i 3 i Rober r CMcPae INVENTOR.

:1 4, 944% 9; 94 9 94 92 BY 7w United States Patent f 3,168,863 SELECTIVE INERTIA LUMBER MARKER Robert C. McRae, 3421 N. 35th, Tacoma, Wash. Filed Feb. 20, 1961, Ser. No. 90,369 4 Claims. (Cl. 101-43) This invention relates to apparatus for marking pieces of lumber and other articles as they move past a marking station.

In the lumber industry it is usual practice to grade lumber according to specified standards and to mark each piece with the grade mark. The marking can be done most expeditiously and to best advantage as the lumber leaves the mill on an off-bearing conveyor moving rapidly at a rate of, for example, 100 lineal feet per minute.

Since it is not practical to slow down or stop the conveyor to permit each piece to be marked, it is no possible to use conventional markers including reciprocating printing heads mounted on a stationary frame at a marking station. The motion of the printing heads of such markers is characterized by a hesitation or dwell at the end of each stroke when the head is in contact with the moving piece. As a result, the mark is blurred.

It is the object of the present invention to provide apparatus for marking moving articles such as pieces of lumber without blurring the mark, even though the pieces are traveling rapidly.

It is another important object of the present invention to provide lumber marking apparatus which operates efficiently on lumber which is warped, crooked, or misaligned on the conveyor.

Still another object of this invention is the provision of lumber marking apparatus adapted for application of commercial grade marks to sorted lumber pieces.

Still another object of this invention is the provision of article marking apparatus suited for application to the selective marking of individual articles on a full scale production basis.

The manner in which the foregoing objects are accomplished will be apparent from a consideration of the accompanying specification and claims considered together with the drawings, wherein:

FIGS. 1 and 2 are side and front elevations, respectively, of the herein described marking apparatus in advanced position;

FIG. 3 is a view in side elevation, similar to FIG. 1, but with the apparatus in retracted position;

FIG. 4 is a schematic diagram illustrating the manner in which the herein described marking apparatus is applied to the selected marking of articles, e.g. pieces of lumber as they are conveyed on a commercial production line; and

FIG. 5 is a schematic wiring diagram of the apparatus of FIG. 4.

Generaly stated, the method of marking articles described herein comprises moving the articles past the marking station at which are located inertia type marking means. The marking means is advanced rapidly toward the selected moving article, the advancing motion being abruptly arrested shortly before contact. The inertia of the marking means then continues its advancement into momentary marking contact with the article after which it is retracted to its starting position, ready for another cycle of operation.

It is a particular feature of the invention that a plurality of markers of the class described may be installed at the marking station, associated with a plurality of electric switches or other actuating devices stationed at intervals along the conveyor on which the articles are conveyed past the marking station. The articles are sorted so that each will energize a selected one of the 3,168,861 Patented Feb. 9, 196.

actuating devices. This, in turn, actuates the associate marker. By this means pieces of lumber may be grade and marked with the grade mark at a rate sufficient t accommodate the entire production of a mill at the norm: production rate.

Considering the foregoing in greater detail and wit particular reference to the drawings:

As shown in FIGS. 1, 2 and 3, the marking apparatu of my invention is mounted at a marking station wit reference to a conveying line 10 on which articles to b marked are conveyed continuously past the station. Th apparatus is mounted on support means such as a leve arm 12 the inner end of which is pivoted through pi: 14 to a frame member 16. The outer portion of leve arm 12 is angled downwardly and supports a markin head indicated generally at 20. This element of th apparatus includes a housing 22 in which is mounted to vertical sliding movement an inertia type plunger 24 The upper end of plunger 24 extends upwardly beyon the plane of housing 22 and is threaded to accommodat a nut 26. Compression spring 28 is interposed betwee. nut 26 and the top surface of housing 22.

A printing or marking die 39 is fixed to the lowe end of plunger 28 and bears on its printing surface th selected lumber grade mark or other marking indiciz Arcuate guide plates 32 are present, one on each sid of the housing, being formed integrally therewith in th illustrated form of the invention.

Drive means are provided for reciprocating arm 12 and marking head 20 carried thereby, toward and awa from the work on conveyor 10. Stop means are assC ciated with the drive means for arresting its advancin movement abruptly as required to impart inertia move ment to plunger 24.

In the form of the invention shown in the drawings the drive and stop means are combined in a single, fluid operated cylinder, specifically pneumatic cylinder 34, th upper end of which is pivoted by means of pin 36 to a extension of frame member 16 and the piston rod 0 which is pivoted by means of pin 38 to bearings carrie by the angled outer end of lever arm 12. Cylinder 3 is of a conventional type and is supplied with air unde pressure through lines 40. It is controlled electricall by means of solenoid 41. It completes a cycle of opera tion, advancing and retracting its piston, upon applica tion of but a momentary electrical impulse to the sole noid. In the at rest position, the cylinder is retracted When a momentary electrical impulse reaches the sole noid through electric wires 42, the piston extends rapidl and slams against a cushion of trapped air. This op erates a pilot valve, not shown, which immediatel reverses the cylinder and returns it to its rest position.

Inking means are associated with the marking heal for supplying ink to the working face of die 30. To thi end a bracket 44 extends outwardly from the frame mem ber 16. It mounts bearings 46 in which a shaft 48 i journaled. Shaft 48 supports a pair of parallel arms 50 52, which mount between them a pair of rollers 54, 56 Roller 54 is an ink-containing reservoir roller; roller 56 in peripheral contact therewith, an applicator roll. Th margins of roll 56 ride on guides: 32.

A spring 58 is mounted between a first post 60 extend ing outwardly from frame 16 and a second post 62 ex tending outwardly from an upward extension of arm 50 Accordingly applicating roll 56 wipes back and fortl across the face of die 30 with each advancement and re traction of the wiping head.

The space between die face 30 and the surface of ar ticles on conveyor 10 is sufficient to accommodate irregu larities which may be present in the articles to be marked For example, when stamping lumber pieces with grad marks, the space may be as much as from one-half t1 hree-quarters inch in order to accommodate pieces of umber which are warped or which have surface irreguarities.

It is a particular feature of the present invention that narking units such as that described above may be emplayed in combination with each other to apply selected grade marks or other identifying indicia to selected categories of articles. Such a system is illustrated in FIGS. 1 and 5, the arrangement being one contemplated for use n sorting lumber on the grading chain of a sawmill, and for applying the corresponding grade mark to each piece.

Thus there is illustrated the grading chain 66 on which are conveyed pieces of lumber 68, 70, 72, 74. Piece 74 purposely is illustrated as being slightly askew, a condi- ;ion which necessarily occurs from time to time in normal nill practice.

Paralleling chain 66 and adjacent thereto is a table 76 Craving spaced longitudinal lines 80, 82, 84, 86 bearing, respectively, the numerals 1, 2, 3 and 4 to indicate the corresponding lumber grades. Substantially aligned with .ines 80, 82, 84, 86, at the outfeed end of table 76 are a plurality of laterally spaced sensing elements, electric switches 90, 92, 94, 96. These are in an electric circuit with a plurality of laterally spaced marking units 100, [02, 104, 106. Each of these bears a grade mark corresponding to lumber grades 1, 2, 3, and 4.

Also included in the electric circuit is a contact switch 98 located downstream from the sensing switches.

The circuit including the switches and marking units is illustrated in FIG. 5. It will be seen that switches 92, 94 and 96 are single pole, double-throw switches, while switches 90, 98 are single pole, single-throw switches. Each of these switches, with the exception of switch 98, upon operation closes a circuit including one of marking units 100, 102, 104, 106. In so doing, each of double throw switches 92, 94, 96 excludes from the circuit all of the marking units except the one it is desired to energize.

Operation The operation of the herein described marking apparatus is as follows: Each marking unit, as illustrated in FIGS. 1, 2 and 3, is energized by an electrical impulse passing through solenoid 41. This causes the automatic extension of cylinder 34 until its piston slams against a pocket of trapped air, as explained above, thereby abruptly arresting its forward motion and instituting its retrac tion to its starting position.

When the cylinder reaches its position of maximum advancement, i.e. the position of FIGS. 1 and 2, its abrupt reversal of motion causes inertia plunger 24, and marking die 30 which it carries, to continue their advancement until the die comes into momentary marking contact with the work carried on conveying line 10. The duration of contact is for so brief an interval, that there is no blurring whatsoever of the stamped mark, even though the work is moving at a rapid rate.

As the printing head advances, it automatically inks the marking die. This is accomplished by the wiping action of inking roller 56, supplied by reservoir roller 54, across the face of die 30 as the die moves from the retracted position of FIG. 3, to the advanced position of FIG. 1 and back to the retracted position of FIG. 3, there being two passes of the inking roller across the die face for each stroke of the latter. This insures effective inking.

Also to be noted is the fact that the inertia movement of the marker accommodates inadvertent irregularities in the height of the articles being marked. This is of particular importance when marking lumber, since the lumber frequently is warped or characterized by surface defects which affects its height.

When the marking units are used in a group, as in FIGS. 4 and 5, lumber pieces 68, 70, 72, 74 are sorted according to grade by an operator standing at table 76. This is accomplished by adjusting the position of the lumher pieces to positions gauged by lines 80, 82, 84, 86, corresponding to lumber grades 1, 2, 3 and 4. Thus, as illustrated, board 68 has been positioned so that its end registers with line 82, board 70, with line 80, board 72, with line 84, and askew board 74 with line 86.

As the boards travel successively beneath marking units 100, 102, 104, 106, they pass contemporaneously beneath actuating or sensing units 90, 92, 94, 96. In the case of board 74, a grade 4 piece, all of the latter switches will be closed. By reference to FIG. 5 it will be seen that as a consequence, marking unit 106 is energized while units 100, 102, 104 are inactivated. Accordingly, when the board closes switch 98, which is in series with the sensing switches, marking unit 106 alone will be energized and will stamp the board with the grade form mark.

Similarly, when board 72 reaches the sensing switches it will operate switches 90, 92, 94 only. As a consequence, marking unit 104, the grade 3 unit, will be actuated while units 100, 102 will be thrown out of the circuit and unit 106 will remain uneffected in its rest position. in a similar manner, board 70 will actuate grade 1 marking unit only, and board 68, grade 2 marking unit 102 only.

If switch 98 were to be omitted, a board which is misaligned, or a curved board, might actuate one of switches 90, 92, 94, 96 before the others, thereby causing an instantaneous operation of the associated marking unit. This possibility is eliminated by locating switch 98 downstream from the sensing switches.

It is to be understood that the form of my invention herein shown and described is to be taken as a preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of my invention or the scope of the subjoined claims. Thus there may be substituted for the spring restrained inertia plunger 24, alternate but equivalent mechanism such as spring hinges, resilient whip arms, and the like.

Having thus described my invention, I claim:

1. Apparatus for marking moving articles which comprises a lever arm, means for pivotally mounting the inner end of the lever arm to a stationary support, drive means coupled to the lever arm intermediate its ends for reciprocating it between advanced and retracted positions, stop means associated with the drive means for abruptly arresting its advancing motion, a spring-retained inertia plunger mounted on the outer end of the arm, a printing die mounted on the plunger for momentary printing contact with articles toward which it is advanced by the drive means, and inking means positioned for movement by the lever arm for inking the printing die on each stroke thereof.

2. The apparatus of claim 1 wherein the printing die is provided with arcuate guides and wherein the inking means comprises inking rollers on a spring-actuated lever arm positioned for movement along the guides, traversing the printing die face with each stroke of the die.

3. Apparatus for marking articles passing a marking station, the apparatus comprising: conveying means for conveying the articles past the station, a plurality of laterally spaced indicator means spaced laterally with respect to the conveying means for identifying the manual position of articles laterally of the conveying means according to type, an electric circuit, a plurality of contact electric switches in series in the electric circuit spaced laterally with respect to the conveying means and corresponding in number and alignment with the indicator means, another contact electric switch located a spaced distance downstream from the first mentioned contact electric switches and in series circuit relationship with them, each contact electric switch being disposed for engagement and actuation by the articles, and a plurality of electrically controlled markers in the electric circuit, each marker being actuated selectively by one of the contact electric switches, provided said another contact electric switch is closed, thereby marking the article positioned with reference to the indicator means.

4. Apparatus for marking moving articles on a surface disposed substantially parallel to the line of movement, the apparatus comprising a lever arm, means for pivotally mounting the inner end of the lever arm to a stationary support, drive means coupled to the lever arm intermediate its ends for reciprocating its outer end between advanced and retracted positions, inertia plunger means mounted on the outer end of the lever arm for movement between advanced and retracted positions substantially corresponding to the direction of movement of the lever arm, resilient means interengaging the lever arm and plunger and urging the latter toward said retracted position, a printing die mounted on the plunger, and stop means associated with the drive means for abruptly arresting the advancing motion of the lever arm short of the surface of the article to be marked, whereby to cause the inertia plunger to be advanced against the resistance of the resilient means to bring the printing die into momentary printing contact with the surface of the article.

References Qited in the file of this patent UNITED STATES PATENTS 1,706,632 Onstad Mar. 26, 1929 1,925,236 Doyle et al. Sept. 5, 1933 2,541,800 Whittaker Feb. 13, 1951 2,559,455 Meyer July 3, 1951 2,603,150 Klug July 15, 1952 2,646,746 Muller July 28, 1953 2,913,978 Lane Nov. 24, 1959 2,952,204 Sherman Sept. 13, 1960

Claims (1)

1. APPARATUS FOR MARKING MOVING ARTICLES WHICH COMPRISES A LEVER ARM, MEANS FOR PIVOTALLY MOUNTING THE INNER END OF THE LEVER ARM TO A STATIONARY SUPPORT, DRIVE MEANS COUPLED TO THE LEVER ARM INTERMEDIATE ITS ENDS FOR RECIPROCATING IT BETWEEN ADVANCED AND RETRACTED POSITIONS, STOP MEANS ASSOCIATED WITH THE DRIVE MEANS FOR ABRUPTLY ARRESTING ITS ADVANCING MOTION, A SPRING-RETAINED INERTIA PLUNGER MOUNTED ON THE OUTER END OF THE ARM, A PRINTING DIE MOUNTED ON THE PLUNGER FOR MOMENTARY PRINTING CONTACT WITH ARTICLES TOWARD WHICH IT IS ADVANCED BY THE DRIVE MEANS, AND LINKING MEANS POSITIONED FOR MOVEMENT BY THE LEVER ARM FOR INKING THE PRINTING DIE ON EACH STROKE THEREOF.

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