US2805060A - High speed feeding mechanism for folding box machines - Google Patents

Description

Sept. 3, 1957 F. M. LEFlEF 2,805,060

HIGH swan FEEDING MECHANISM FOR FOLDING BOX MACHINES 5 Sheets-Sheet 1 INVENTOR. Frank M. Lef/ef Sept. 3, 1957 2,805,060

HIGH SPEED FEEDING MECHANISM FOR FOLDING BOX MACHINES Filed April 15, 1955 5 Sheets-Sheet 2 x i f F (4:? :7 H V 45 N QR Q Q- x o o I! O i H r [w & i I 46 f? ,[i' a U P f! U f {8 i is or 24 H of F 28 0 o O o o o 0 o n L \K V n g o T o KLL a! i ..r I M 8 4 4.9

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INVENTOR.

Frank M. Lefzef H-HM 5. 1244M l ATTORNEY P 3, 1957 F. M. LEFIEF $2,805,060

HIGH SPEED FEEDING MECHANISM FOR FOLDING BOX MACHINES Filed April 15. 1955 5 Sheets-Sheet 3 INVENTOR. Frank M. Lefz'ef BY A MA '5. [2 44.42

ATTORNEY Sept. 3, 1957 F. M. LEFIEF 2,805,060

HIGH SPEED FEEDING MECHANISM FOR omnmc BOX MACHINES Filed April 15, 1955 5 Sheets-Sheet 4 INVENTOR. Frank M. Zefief ATTORNEY Sept. 3, 1957 F. M. LEFIEF 2,305,060

HIGH spasm FEEDING MECHANISM FOR FOLDING BOX MACHINES Filed April 15, 1955 5 Sheets-Sheet 5 8 INVENTOR.

Fran/c M. Lefzef HM W A TJ'ORNEY United States Patent HIGH SPEED FEEDING MECHANISM FOR FOLDING BOX MACHINES Frank M. Lefief, Palo Alto, Calif., assignor, by mesne assignments, to Baljak Corporation, Wilmington, De!., a corporation of Delaware Application April 15, 1955, Serial No. 501,462

6 Claims. (Cl. 271-11) This invention relates to improvements in blank feeding mechanisms for folding box machines of the type in which fiat, or nearly flat blank of foldable sheet material, for example paperboard, is forced through a folding die by a plunger to fold the blank into hollow box form.

Machines of the aforementioned type, in addition to folding the blank during its passage through the die, generally also perform a locking operation on the blank to lock certain blank portions, such as walls, panels, tabs or flaps together so that these blank portions thereafter remain locked in box forming position without the aid of additional connecting means, such as adhesive, staples, rivets, or the like.

However, the invention is not limited in its application to machines for the glueless assembly of folding boxes but offers many advantages, if applied to die and plunger machines for setting up glued boxes.

The success of the folding operation performed by a plunger and die mechanism depends in a large measure on the accuracy with which a box blank is deposited on the die. If the blank is slightly out of position at the moment the plunger engages it, the blank will not fold at the intended fold lines and, if it is of the self-locking type, the locks will generally not engage. Consequently the blank must be discarded as waste. In many instances a misplaced blank also jams in the mechanism and requires stopping of the machine in order to remove it.

The prior patent of Thomas R. Baker and Edward J. Pagendarm, No. 2,624,249, issued January 6, 1953, discloses a blank feeding mechanism of the general type to which this invention relates. The mechanism comprises basically one, or a plurality of vacuum powered suction cups which are moved by a mechanical mechanism in such a way as to pick up a blank at a certain withdrawal position, for example by removing it from the end of a stack of blanks. The withdrawn blank is then moved along a prescribed and controlled path to a deposit position, for example to a folding die through which a plunger subsequently forces the blank. The position in which the blank is deposited is remote from the position at which the blank is picked up and generally lies at an angle with respect thereto.

Prior to action by the plunger on the blank, the blank may be prc-folded, or certain creases be broken by the action of the feeder which in such instances does not release the blank until the blank has passed certain obstacles, for example elements of a pro-folding die lying above, or in advance to, the main folding die. This aspect forms the subject matter of a patent to Thomas R. Baker and Frank M. Lefief, No. 2,655,843, issued October 20, 1953.

The present invention is concerned with certain improvements of the blank feeding and blank handling mechanisms disclosed in the aforementioned patents and its primary object is to modify the action of the mechanism which controls the motion of the pneumatic feeder ice in such a way as to permit greatly increased machine speeds without objectionable vibration.

Observations have shown that an increase in the production rate leads to disturbances, primarily vibrations, which have their source in two phenomena, acceleration and deceleration problems, and problems of air resistance.

The feeding and blank handling mechanism disclosed in the aforementioned patents executes a motion which is best described by reference to the travel of the blank.

The blank is first removed from the magazine in a direction substantially normal to its plane. This is basically a translatory motion. The blank is then swung through an are into the new angular position opposite the folding die or dies. This second phase of motion is basically a rotative or oscillatory motion, the center of oscillation being at some distance from the plane of the blank. During the second phase of motion the blank is greatly accelerated until it reaches its maximum speed at a point approximately half way along the arc on which the blank moves, followed by a rapid deceleration when the second phase of motion terminates.

The second phase of motion is then followed by another translatory motion during which the blank is deposited on the folding die or is forced into the prefolding die, as the case may be. It is evident that the first and third phases of motion must be executed at a slow rate since the blank encounters substantial air resistance when it is moved in a direction normal to its plane.

The rapidity with which all motions must be carried out is readily appreciated from the fact that machines incorporating the present invention are in successful commercial operation with a production rate of 385 boxes per minute for a machine fitted with two dies and two plungers.

The improved feeder control mechanism which forms the subject of the present invention modifies the oscillatory phase of the feeder motion by substantially reducing the peak velocity which is reached at a point midway of the are through which the blank is moved. This is accomplished by continuously varying the radius of oscillation in a controlled fashion. It this way the angular acceleration of the suction feeder is reduced materially without shortening the path of travel or impairing the other qualities and features of the mechanism.

Also, the invention renders unnecessary the use of cams in the drive mechanism, so that the drive of the feeder is positive in all respects and is essentially reduced to rotative and oscillatory motions which permit more effective static and dynamic balancing than cam-and-follower mechanisms.

These and various other objects, features and advantages of the invention will appear more fully from the detailed description which follows accompanied by drawings showing, for the purpose of illustration, a preferred embodiment of the invention. The invention also consists in certain new and original features of construction and combination of elements hereinafter set forth and claimed.

Although the characteristic features of this invention which are believed to be novel will be particularly pointed out in the claims appended hereto, the invention itself, its objects and advantages, and the manner in which it may be carried out may be better understood by referring to the following description taken in connection with the accompanying drawings forming a part of it in which:

Fig. 1 is a perspective view of the improved feeding mechanism in the position in which a box blank is about to be withdrawn from the blank magazine;

Fig. 2 is a perspective view of the actuating mechanism of the feeder in the position in which the blank is about to be deposited on the die, the suction cups of the feeder being omitted for the sake of clarity;

Fig. 3 is a perspective view showing the feeding mechanism, two magazine gates, two plungers and two dies from a slightly different angle of view, but substantially in the same operating position as shown in Fig. 2';

Fig. 4 is a partially diagrammatic elevational view representing the geometry of the feeding mechanism;

Fig. 5 is a perspective view of the box assembly machine', certain elements of the machine such as suction cups, plungers and magazine gates being removed for the sake of clarity. This figure illustrates the joint driving mechanism for the plungers and the feeder;

Figs. 6 to 8 are simplified diagrams illustrating the geometry of the feeding mechanism in contrast to the feeding mechanism of prior Patent 2,624,249.

In the following description and in the claims, various details will be identified by specific names for convenience. The names, however, are intended to be generic in their application. Corresponding reference characters refer to corresponding parts in the several figures of the drawings.

In the drawings accompanying, and forming part of, this specification, certain specific disclosure of the invention is made for the purpose of explanation of broader aspects of the invention, but it is understood that the details may be modified in various respects without departure from the broader principles of the invention, and that the invention may be applied to other structures than the one shown.

Referring to the drawings, the machine comprises a main supporting framework of which a portion is visible at 11 in Figure 1. This framework supports the various elements of the machine including a blank magazine 12 comprising a withdrawal gate 13 through which individual box blanks B of a stack 14 resting on rods 15 may be withdrawn by suction cups 16. In the illustrated machine there are three suction cups for each stack of box blanks. The suction cups are mounted on a common transverse bar 17 of preferably rectangular cross-section.

The ends of the transverse bar 17 are secured to a pair of double-armed gripper arms 18 of substantially identical construction, one of these arms being visible in Figure I. Since the actuating mechanisms at both ends of the bar 17 are substantially identical it will be sufficient to describe the construction of operation of one of them. Flexible tubing 19 connects the suction cups 16 to a suitable source of suction, for example a vacuum pump (not shown).

The gripper arm [ST is pivotally supported on a first bell-crank lever 20 at 21. The shorter arm 22 of the double-armed gripper arm 18 carries the transverse bar 17 and the longer arm 23 is provided with guideways 24 (see also Figure 4) engaging a pivot 25 with freedom of pivotal movement about, and sliding movement relatively to, the pivot 25.

The pivot 25 itself is not stationary, but is mounted on a second bell-crank lever 26, the latter being pivotally mounted on the main supporting framework 11 of the machine at 27. The second bell-crank lever 26 is linked to the first bell-crank lever 20 by a connecting rod 28 engaging the second bell-crank lever at 29 and the first bell-crank lever at 30.

The first bell-crank lever 20 is pivotally mounted at 31 on the main supporting framework 11. It therefore becomes apparent that oscillation of the first bell-crank lever 20 about its axis 31 results in oscillation of the second bell-crank lever 26 about the axis 27 of the latter by reason of the connecting rod 28 between the two bellcrank levers.

The first bell-crank lever comprises a further pivot 32 (Figures 1 and 4) from which a further connecting rod 33 extends to a rocking arm 34 (Figures 4 and 5). The rocking arm 34 is double-armed and is centrally pivoted on the main supporting framework 11 at 35. The second arm 36 of the rocking arm 34 is connected 4 by a 'bar or rod 37 to a drive crank 38 on the drive shaft 39 of the machine. The drive shaft 39 is driven by a motor 40 through a train of reduction gears of which one is visible at 41.

Referring to Figure 5, the drive crank 38 operates a further link 42 extending to an arm 43. One end of the arm 43 is linked to mechanism for operating the plungers of the machine, and the other end of the arm 43 is pivotally supported on an eccentric pivot 44.

The mechanism for operating the plungers of the machine comprises a transverse plunger bar 45 mounted on cross heads 46. The cross heads 46 are slidable on vertical rods of which one is visible at 47 in Figure 5. The cross heads are connected to the actuating arm 43 in a suitable manner (not visible in detail in Figure 5) so that actuation of the arm 43 by the crank 38 results in a vertical reciprocating movement of the plunger bar 45.

Turning to Figure 3, the plunger bar 45 carries a pair of plungers 48 which cooperate with folding dies 49 on which the deposited blanks B rest and through which they are forced by the plungers for setting up the blanks into box form.

Referring now to Figures 4 and 5, the action and motion of the feeder and of its actuating mechanism is readily followed.

Rotation of the drive crank 38 results in an oscillating motion of the rocking arm 34. The rocking arm 34, in turn, imparts an oscillating motion to the first bell-crank lever 20 (Figure 4). The first bell-crank lever oscillates between two end positions of which one is shown in solid lines in Figure 4, the other end position being shown in broken lines. In the one end position blanks are removed from the stack 14 and in the other end position blanks are deposited on the folding die as shown at B in Figure 3.

Oscillation of the first bell-crank lever 20 results in a complex motion of the gripper arm 18 whose cnd slides and pivots relatively to the pivot 25. This pivot swings on an are 56 since it is mounted on the second bell-crank lever 26 operated by the first bell-crank lever 20 through the connecting rod 28.

In order to follow the motions of the various elements of the mechanism more conveniently, six successive positions are shown in Figure 4 identified by numerals l to 6, each increment representing 36 degrees of rotation of the drive crank 38.

The equal increments 1 to 6 on the circle 50 of the drive crank 38 are converted into corresponding unequal increments numbered 1 to 6 on the are 51 of the rocking arm 34. More particularly the first and last increments are the smallest on the arc 51, whereas the increment between positions 3 and 4 is the largest.

Turning now to the corresponding positions on the arcs 52, 53 and 54 of the first bell-crank lever 20 the first increment between positions 1 and 2 is extremely small. This, as will later be seen, represents the withdrawal motion of blanks B from the magazine. The second and third increments increase in size whereas the last increment between positions 5 and 6 is smaller than the preceding one. The last increment corresponds to the motion by which the blank B is placed on, or pressed into, the folding die 49.

Pivot 30 of the lever 20 is linked to pivot 29 on the second bell-crank lever 26 by the connecting rod 28. The path of the pivot 29 is represented by the are 55 and the path of the pivot 25 engaged by the feeder arm 22 is represented by the arm 56.

The first increment on both arcs 55 and 56 is extremely small, the second, third and fourth increments are progressively larger and the last increment between positions 5 and 6 is considerably smaller than the preceding one. The significance and purpose of the motion of the pivot 25 is best explained by reference to the diagrams, Figures 6 to 8.

Of these diagrams, Figures 6 and 7 represent, by way of comparison, a mechanism in which the pivot 25 is fixed and is not employed. In these figures the are 54 represents the path of the pivot 21, about which the gripper arm 18 swings on the first bell-crank lever 20. Figure 6 assumes that the plane of the withdrawal gate of the feeder is truly vertical, represented by the vertical line 57, and it also assumes that the plane of deposit of the blank is truly horizontal, represented by the horizontal line 58. The angle between the pick-up position of the blank and its deposit position is 90 degrees.

At the half-way point of the are 54 the distance between the pivots 21 and 25 is smallest and is represented by D. In this position the pivots 25 and 21 lie in a straight line with the pivotal axis 31 of the first bell-crank lever. At this point the double-armed gripper arm 18 and the gripper bar 17 (Figure 4) move at peak velocity during their travel from the magazine gate to the folding die or vice versa. It is an object of this invention to reduce this peak velocity without reducing the rate of operation of the machine.

It has been found advantageous to set the withdrawal gate of the magazine at a ten degree slant, as represented in Figure 7. This is done to facilitate continuous feeding of the stack 14 of the blanks towards the magazine gate during operation of the machine.

The slanted arrangement creates an even less favorable condition, since it results in an increase in the velocity of the gripper arm at its half-way point. This is due to the fact that the distance d between the pivots 21 and 25 is smaller in this arrangement than it was in the 90 degree arrangement shown in Figure 6.

Turning now to Figure 8, representing the operation of the invention, a decrease in the peak velocity of the gripper arm 18 is brought about by an increase in the distance between the pivots 21 and 25. As previously explained, the pivot 25 is not fixed, but moves on an are 56 about a pivot 27 which is the pivot of the second bellcrank lever. The motion of the second bell-crank lever is so controlled that the points 31, 21 and 25 are always in a straight line.

It is at once apparent that the arrangement results in an increase of the distance between the pivots 21 and 25, as compared to Figure 7, by an amount d equal to the distance between the pivots 25 and 27. The total distance between the pivots 21 and 25 is represented by d plus d totaling D which is even greater than D, the most favorable previous arrangement of Figure 6. As a result of the increase in the distance between the pivots 21 and 25 the suction cups 16 on the feeder bar 17 (Figure 4) travel at a substantially reduced rate. Wind resistance is reduced, the rate of acceleration and deceleration is greatly decreased, resulting in smoother and quieter operation of the machine than would be attainable without the invention.

Considering now the motion of the mechanism in detail, as shown in Figure 4, the path of the feeder bar 17 is represented by the line 60 on which the various positions 1 to 6 of the feeder bar are also shown in broken lines. It is apparent that the removal of the blank from the magazine gate takes place at an extremely slow rate, as represented by the increment l, 2. This insures positive removal of the foremost blank without disturbing the next blank by suction between the blanks.

During the first phase of the motion the blank performs a translatory motion, removing the blank from the stack. The blank is then swung to travel, edge first, with a minimum of air resistance as its rate of travel increases between positions 3 and 4, reaching its peak velocity shortly after position 4, when the pivots 21, 27 and 25 move into a straight line with pivot 31. The blank then decelerates gradually to be deposited in or on the folding die 49 in position 6.

The entire drive is positive and the complex motion of the feeder is produced entirely by cranks, levers and connecting rods without cams, cam followers and springs.

This construction permits effective static and dynamic balancing of the driving mechanism, and the relatively low peak velocity obtained by the controlled movement of the point of pivotal and sliding engagement of the gripper arm permits attainment of high production rates.

What is claimed is:

l. A high speed feeding mechanism for removing single blanks of foldable sheet material from a withdrawal position and plane, for example from the end of a stack of blanks and moving the withdrawn blank to, and deposit it in, a deposit position and plane, for example on a folding die through which a plunger is movable, said deposit position and plane being remote from, and lying at an angle with respect to, said withdrawal position and plane, the feeding mechanism comprising, a main support; a main crank pivotally mounted on said support; a bearing having an axis spaced from, and parallel with, the pivotal axis of said main crank; a double armed gripper arm pivotally mounted on said main crank, one arm of the gripper arm having rotative and slidable engagement with said bearing; a suction gripper mounted on the other arm of said gripper arm; means for imparting an oscillatory motion to said main crank about its axis; and means operable in dependence on the oscillatory motion of said main crank lever for varying the distance of said hearing from the pivotal axis of said main crank.

2. A high speed feeding mechanism for removing single blanks of foldable sheet material from a withdrawal position and plane, for example from the end of a stack of blanks and moving the withdrawn blank to, and deposit it in, a deposit position and plane, for example on a folding die through which a plunger is movable, said deposit position and plane being remote from, and lying at an angle with respect to, said withdrawal position and plane, the feeding mechanism comprising, a main support; a main crank pivotally mounted on said support; a bean ing having an axis spaced from, and parallel with, the pivotal axis of said main crank; a double armed gripper arm pivotally mounted on said main crank, one arm of the gripper arm having rotative and slidable engagement with said bearing; a suction gripper mounted on the other arm of said gripper arm; means for imparting an oscillatory motion to said main crank lever about its axis; a movable support for said bearing, said movable support being mounted on said main support so as to permit variations in distance between said bearing and the pivotal axis of said main crank; and means operable in dependence on the oscillatory motion of said main crank for moving said movable bearing support in such a way that the aforesaid distance is a minimum at the ends of the oscillatory motion of said main crank and a maximum at substantially the medial position of the oscillatory motion.

3. A high speed feeding mechanism for removing single blanks of foldable sheet material from a withdrawal position and plane, for example from the end of a stack of blanks and moving the withdrawn blank to, and deposit it in, a deposit position and plane, for example on a folding die through which a plunger is movable, said deposit position and plane being remote from, and lying at an angle with respect to, said withdrawal position and plane, the feeding mechanism comprising, a main support; a main crank pivotally mounted on said support; a hearing having an axis spaced from. and parallel with the pivotal axis of said main crank; a double armed gripper arm pivotally mounted on said main crank, one arm of the gripper arm having rotative and slidable engagement with said bearing; a suction gripper mounted on the other arm of said gripper arm; means for imparting an oscillatory motion to said main crank about its axis; a movable support for said bearing, said movable hearing support being pivotally mounted on said main support, so as to permit said bearing to move on an are about the pivotal axis of said movable support; and means for oscillating said movable support in timed relationship with the oscillatory motion of said main crank.

4. A high speed feeding mechanism for removing single blanks of foldable sheet material from a withdrawal position and plane, for example from the end of a stack of blanks and moving the withdrawn blank to, and deposit it in, a deposit position and plane, for example on a folding die through which a plunger is movable, said deposit position and plane being remote from, and lying at an angle with respect to, said withdrawal position and plane, the feeding mechanism comprising, a main support; a main crank pivotally mounted on said support; a bearing having an axis spaced from, and parallel with, the pivotal axis of said main crank; a double armed gripper arm pivotally mounted on said main crank, one arm of the gripper arm having rotative and slidable engagement with said hearing; a suction gripper mounted on the other arm of said gripper arm; means for imparting an oscillatory motion to said main crank about its axis. a movable support for said bearing, said movable bearing support being pivotally mounted on said main support, so as to permit said bearing to move on an are about the pivotal axis of said movable support; and a connecting rod linking said movable support and said main crank for joint oscillatory motion.

5. A high speed feeding mechanism for removing single blanks of foldable sheet material from a withdrawal position and plane, for example from the end of a stack of blanks and moving the withdrawn blank to, and deposit it in, a deposit position and plane, for example on a folding die through which a plunger is movable, said deposit position and plane being remote from, and lying at an angle with respect to, said withdrawal position and plane, the feeding mechanism comprising, a main support, a first bell-crank lever pivotally mounted on said support, a bearing having an axis spaced from and parallel with the pivotal axis of said first bell-crank lever; a double armed gripper arm pivotally mounted on one arm of said first bell-crank lever, one arm of the gripper arm having rotative and slidable engagement with said bearing; a suction gripper mounted on the other arm of said gripper arm; means for imparting an oscillatory motion to said first bell-crank lever; a second bell-crank lever mounted on said main support about an axis spaced from and parallel to, the axis of said first bell-crank lever, said second bellcrank lever carrying said hearing, so as to permit said bearing to move on an arc about the axis of said second bell-crank lever; and a connecting rod linking said two bellcrank levers for joint oscillatory motion, said bearing being so mounted on said second bell crank lever that in the medial position of its oscillatory motion the two axes of the bell-crank levers and the axis of the said bearing lie substantially in line.

6. A high speed feeding mechanism for removing single blanks of foldable sheet material from a withdrawal position and plane, for example from the end of a stack of blanks and moving the withdrawn blank to, and deposit it in, a deposit position and plane, for example on a folding die through which a plunger is movable, said deposit position and plane being remote from, and lying at an angle with respect to, said withdrawal position and plane, the feeding mechanism comprising, a main support, a first bell-crank lever pivotally mounted on said support, a bearing having an axis spaced from and parallel with the pivotal axis of said first bell-crank lever; a double armed gripper arm pivotally mounted on one arm of said first bell-crank lever, one arm of the gripper arm having rotative and slidable engagement with said bearing; a suction gripper mounted on the other arm of said gripper arm; a drive crank capable of continuous rotation; a rocking arm mounted on said main support for oscillatory motion; a first connecting rod linking said rocking arm to said drive crank; a second connecting rod linking said rocking arm to said first bell-crank lever thereby imparting an oscillatory motion to said bell-crank lever; a second bell-crank lever mounted on said main support about an axis of oscillation spaced from, and parallel to, the axis of said first bell-crank lever, said second bellcrank lever supporting said hearing at a distance from the axis of said second bell-crank lever whereby the said bearing is capable of moving on an are about said last named axis, and a third connecting rod linking said two bell-crank levers for joint oscillatory motion.

References Cited in the file of this patent UNITED STATES PATENTS 1,553,738 Arey Sept. 15, 1925 2,545,292 Magnusson Mar. 13, 1951 2,568,069 Herr Sept. 18, 1951 2,624,249 Baker Jan. 6, 1953 FOREIGN PATENTS 676,216 Great Britain July 23, 1952

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