US3269724A

US3269724A - Blank feeding devices

Info

Publication number: US3269724A
Application number: US410179A
Authority: US
Inventors: Frank M Lefief
Original assignee: Kliklok LLC
Current assignee: Kliklok LLC
Priority date: 1964-11-10
Filing date: 1964-11-10
Publication date: 1966-08-30
Anticipated expiration: 1983-08-30
Also published as: SE322975B; GB1083400A; DE1285854B

Description

Aug. 3@, 1966 LEHEF 3,269,724-

BLANK FEEDING DEVI CES Filed Nov. 10, 1964 8 Sheets-Sheet l INVENTOR Frank M. Lef/ef Aug 3@, 3966 F. M. LEFIEF BLANK FEEDING DEVICES 8 Sheets-Sheet 2 Filed Nov. 10, 1964 INVENTOR.

Frank M Zef/ef WM MM ATTORN/FV F. M. LEFIEF BLANK FEEDING DEVICES 8 Sheets-Sheet 3 INVENTOR. Frank M. Zef/ef ATTORNEY Aug 3%, 1966 F. M. LEF'IEF' BLANK FEEDING DEVICES 8 Sheets-Sheet 4 Filed Nov. 10, 1964 R. f .6 a ml WM H 0 H w A TTORNE Y Aug 3Q, 195% LEFlEF 3,259,724

BLANK FEEDING DEVICES Filed NOV. lO, 1964 8 Sheets-Sheet 5 INVENTOR. Fran/r M. Lefl'ef ATTORNEY Aug. 30, 1966 F. M. LEFIEF 3,269,724

BLANK FEEDING DEVICES Filed Nov. 1964 8 Sheets-Sheet 6 Frank M Leif/6f W I I I TTOR/Vgy Aug, 3Q, 1966 8 Sheets-Sheet 7 Filed Nov. 10, 1964 Fig. 7

INVENTOR. Frank M. lef/ef (4) ATTORNEY Aug, 36, 196 F. M. LEFIEF BLANK FEEDING DEVICES 8 Sheets-Sheet 8 Filed Nov. 10, 1964 INVENTOR.

Frank M. Lef/ef 41 ATTORNH r; 3,269,724 Ice Patented August 30, 1966 3,269,724 BLANK FEEDING DEVICES Frank M. Lefief, Palo Alto, Calif., assignor, by mesne assignments, to Kliklok Corporation, New York, N.Y., a corporation of Delaware Filed Nov. 10, 1964, Ser. No. 410,179 15 (Ilairns. (Cl. 271-27) This invention relates to improvements in blank feeding devices of the type which transport a flat folding box blank from a pickup position at which the blank is substantially vertically disposed, as it is for example at the discharge gate of a horizontally extended magazine in which blanks rest on edge, to a lower deposit station at which the blank is deposited, for example in the path of a box forming plunger Which subsequently moves the blank through a folding die in order to fold it into box shape.

Various problems are encountered in instances where blanks must be fed at a rapid rate, yet must be accurately positioned at the delivery station, or where blanks are of a large size, or where blanks tend to adhere to one another in the magazine, either by reason of their configuration or by reason of their composition, such as coated blanks which tend to warp, or where the size of the blanks makes it difiicult to form a sufficiently extended blankseparating film of air between the foremost blank in the magazine and the next blank.

Experience has shown that a dependable withdrawal of the blanks from the magazine gate requires a relatively slow initial motion at the magazine, as a rapid or abrupt motion during this phase fails to separate the blanks and also frequently causes the removed blank to shift relatively to the suction cup which grasps it, as a consequence of which the blank is misaligned thereafter. Misalignment generally results in the formation of a misshapen box.

It is undesirable to feed blanks by friction means or to permit the blank to move under the action of gravity during any portion of the feeding motion.

It is known to transport blanks vertically between transport belts which engage the blanks by friction. Such feeders lack accuracy in depositing the blanks in a precise deposit position and also necessitate abrupt deceleration of the moving blanks by stops from which the blanks may rebound or by which the blanks may become indented at the edges. Rebounding also occurs where blanks are permitted to move under the influence of gravity during the terminal portion of the feeding motion.

The present invention provides a reciprocating blank feeder or blank transport device which positively moves blanks, one at a time, from an accurately defined withdrawal position to a deposit position at which the blank is deposited with equal accuracy. The motion of the feeder mechanism involves a slow withdrawal followed by a fast transport motion which is eventually slowed to zero at the point at which the blank is released. The return motion of the feeder mechanism proceeds at an even higher rate of speed than the transport motion. In this manner a high feed rate per minute is attainable by an appropriate variation in the velocity of the blank grasping vacuum cups during each feed and return cycle.

As will be seen from the detailed description which follows, the variation of the velocity may be accomplished by a relatively uncomplicated crank and lever arrangement for moving a feed carrier which runs in a track, a portion of which may also be curved in order to modify the velocity of the feeder cup.

The various features, objects 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 resides in certain new and original features of construction and combination of elements hereinafter set forth and claimed.

Although the characteristic features of the 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 feeder mechanism in its upper extreme position;

FIGS. 2, 3 and 4 are perspective views of successive positions of the feeder mechanism during its feed stroke, the blank being released in FIG. 4, and the forming die which is visible in FIG. 1 being swung out of the way to expose the feeder fully;

FIG. 5 shows the feeder during its return stroke;

FIG. 6 is a perspective view of the drive mechanism of the feeder;

FIG. 7 is a perspective view of a portion of the drive mechanism and of the vacuum control; and

'FIG. 8 is a diagrammatic illustration of the mechanics of the feeding device and its drive mechanism in sixteen successive positions.

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.

The drawings accompanying, and forming part of, this specification disclose certain specific details of construction for the purpose of explanation of broader aspects of the invention, but it should be understood that structural details may be modified in various respects without departure from the principles of the invention and that the invention may be incorporated in other structural form-s than shown.

A stack of flat folding box blanks B rests on edge on a pair of rearwardly extending and slightly upwardly inclined supporting rods 11 of which only the right rod is visible. The rods 11 rest in mounting brackets 12 and discs or washers 13 of a diameter somewhat larger than the diameter of the rods 11 form blank retainers which prevent the foremost blank from falling out of the magazine under the pressure of the stack behind it, yet permit withdrawal of individual blanks by the blank feeder about to be described. When being withdrawn the foremost blank flexes slightly when being pulled past the obstructions 13.

Other blank retaining elements are lateral fingers 14 and, at still higher levels, aligning

brackets

15 and 16 all of which marginally overlap the foremost blank.

The aligning

brackets

15 and 16 comprise horizontal shoulders extending into slits or notches 17, 18 of the blanks, one such shoulder being visible at 19.

Further lateral aligning means include lateral aligning rods 20 (only the right rod being visible) and aligning plates 21.

All these aligning means serve to maintain the blanks in a very accurately defined position at the magazine gate which comprises a substantially

rectangular framework

22, 23, 24 and 25 to which the several aligning and blank retaining elements are secured. The magazine gate is slightly forwardly inclined and its plane forms an acute angle with respect to the vertical plane. The magazine gate represents the Withdrawal station at which the blanks are removed, one by one, by the feeder and transported to a lower deposit station located in the present embodiment in front of a box forming die of basically known design.

The die comprises a heavy framework 26 hinged-1y mounted on a vertical hinge axis 27 to permit the die to be swung out of the way, thereby exposing the deposit station of the feeder proper (FIGS. 2 to 5).

Opposite the die hinge 27 a heavy yoke 28 serves to lock the die in operative position (FIG. 1) by means of a quick release clamping device 29.

When locked the yoke 28 bears against studs 30 on the machine frame and also bears against the plunger of a microswitch 31 which, when depressed, permits the machine to be operated, but which, when open, interrupts the electrical circuit of the drive.

In order to take the sequential photographs on which FIGS. 2 to 5 are based, it was necessary to actuate the switch 31 by an adjustable screw stud 32 (FIG. 2) on the clamping device 29 to make up for the thickness of the yoke.

The folding die comprises

cam devices

33, 34 for folding the

side walls

35, 36 of the blank, and

end rollers

37, 38 for folding the box ends, the latter being composed of

outer end panels

39, 40 and inner end panels of which

panels

41, 42 are on the left and panels 43, 44 are on the right. The central bottom panel 45 is engaged on its back side by the box forming plunger (FIG. 2) later referred to.

The blank feeder comprises a pair of vacuum or suction cups 48 mounted on

arms

49, 50 on a square transverse bar 51. The square bar 51 is fitted with rollers 52 at its extreme ends. The rollers run in vertically extended tracks 53 (only the left track being visible), the lower portion 54 of the track being straight and substantially vertical, the upper portion 55 being curved toward the magazine gate (best seen in FIG. 4).

A round bar 56 extends parallel to the square bar and is also fitted with rollers 57 at its extreme ends running in the same tracks 53 on both sides of the magazine. The

bars

51 and 56 are connected by links 58. The assembly of

bars

51, 56 and links 58 may be considered a carriage running in the tracks 53, adapted by reason of its articulated construction to follow the track curvature.

The

carriage

51, 56, 58 is moved up and down the track 53 by push rods 59.

It is apparent that the attitude of the vacuum cups 48 may be changed by tilting the square bar 51. Since, further, the cups 48 are mounted on arms tilting of the bar 51 produces a motion of the cups 48 toward, and away from, the magazine gate.

This is accomplished conveniently in the illustrated embodiment by a control or tilt arm 60 secured to the square bar at 61 and fitted at its end with a roller 62 running in a further vertical track 63.

When the

feeder carriage

51, 56, 58 enters the curved track portion 55, the roller 62 of the control arm 60 continuing in its vertical track 63 causes the bar 51 to tilt in a direction to move the vacuum cups 48 toward the magazine gate. Conversely, downward movement of the feeder carriage causes the bar 51 to be tilted in the opposite sense and the vacuum cups to be withdrawn from the magazine gate (compare FIGS. 1 and 2).

Forward guide rods 64 and rear guide rods 65 define a substantially vertical gap or passageway 66 between them for guiding the extreme lateral portions of a blank grasped by the cups 48 of the downwardly moving

carriage

51, 56, 58.

The feeder carriage further carries a vent valve 67 comprising a rearwardly extending arm 68. When lifted, the

arm 68 uncovers a vent port (not visible) to the atmosphere and relieves the vacuum in a vacuum line 69 extending to a Y-connection 70 from which two branch ducts 69' lead to the cups 48.

The remainder of the vacuum system is best traced in FIG. 7.

A vacuum line 71 leads from a vacuum pump 72 to a main control valve 73 of known construction. Its movable valve member carries a vane 74 which lies in the path of two stops or projections 75 of an oscillating arm or lever 76 of the drive mechanism. Only the upper stop 75 is visible, the lower stop being hidden by the vane 74.

When the arm 76 moves up the lower stop strikes the underside of the vane 74 and moves it into the position shown in FIG. 7. In this position vacuum is transmitted through the valve 73 into a line 77 tied to the right push rod 59 and leading to a T connection 78 immediately left of the vent valve 67 (FIG. 2), thus transmitting vacuum to the line 69 as long as the vent valve 67 remains closed and the position of the vane 74 remains undisturbed.

The condition prevails during most of the downstroke of the oscillating arm 76. At the end of the downstroke the upper stop 75 (FIG. 7) strikes the vane 74 from above and relieves vacuum in the line 77 by exposing to the atmosphere a vent port in the valve body 73. Atmospheric pressure then prevails in the line '77 during most of the upstroke of the oscillating arm 76. Immediately before reaching the top position of its stroke the lower stop 75 strikes the vane 74 from below and reestablishes vacuum in the line 77.

The vent valve 67 (FIG. 2) mounted on the feeder carriage is capable of venting the vacuum in line 69 and branches 69 immediately and without time delay due to the small volumetric capacity of the vacuum line portions 69 and 69'.

The valve 67 serves a double function. Within the reach of its arm 68 a signal element 79 is provided which is normally raised. It is so shown in FIG. 2. When raised, the valve arm 68 passes underneath the signal element and the valve 67 remains undisturbed. This condition prevails during normal operation of the machine.

If, however, it is desired to interrupt the production of the box forming machine without stopping the machine itself, the signal element 79 is lowered, in which position the valve arm 68 rides up on it and actuates the valve 67. Vacuum is then relieved at the cups 48 and no blanik is fed.

Due to the length of the rearwardly extending arm 68, the arm 68, in turn, locks the signal element 79 in its prevailing position and prevents a change in the signal from becoming effective during the period in which the cups 48 are close to the magazine gate. A change in the signal from demand to no-demand, or from no-demand to demand therefore remains ineffective during the brief period during which the cups are capable of grasping a blank. This feature prevents a blank from being released immediately after being picked up, which may then lead to misfeeding and forms the subject matter of an earlier Patent No. 3,089,698 to Thomas R. Baker et al. in which also details of the construction of the valve 67 is shown.

A signal duct 80 extends from the valve 67 downwardly to a control device 81 which is of no further importance in considering the operation of the feeder mechanism. Suffice it to say that the control mechanism 81 may serve to interrupt the operation of a glue applicator with which the box forming machine may be equipped.

The second function of the vent valve 67 on the

feeder carriage

51, 5 6, 58 is to vent the vacuum at the cups at the moment the feeder has reached its lowermost position. As best seen in FIG. 3, a bracket 82 is mounted in the path of the arm 68 of the valve 67. When the feeder carriage reaches the position in which the blank is to be released (FIG. 4) the valve arm 68 strikes the bracket 82 and vents the vacuum at the cups 48.

In FIG. 4 the cups are shown after release of the blank B at its delivery station at which the blank is held in position by a stop 83 on which the bottom edge of the blank comes to rest. In this position the bottom panel 45 of the blank B is accurately lined up with the box forming plunger 46 which, during the upstroke of the feeder and as soon as the feeder mechanism has cleared the path of the plunger, moves forward to force the blank through the forming die (see FIG. 1). In the meantime the feeder returns to pick up the next blank. FIG. 5 shows the feeder mechanism during the initial phase of its upward return motion at a moment at which the box forming plunger is still a certain distance rearwardly of the delivered blank B Summary of feeder operation Beginning with FIG. 5 showing the feeder carriage during its upward return stroke, the arms 49 of the vacuum cups 48 are nearly perpendicular and the cups clear the delivered blank B by a sufiicient margin.

As the carriage enters the curved portion 55 of its track 56 (FIG. 1) the control arm 60 of the square bar 51 continues its travel within the straight track 63, as a result of which the arms 49 of the feeder cups 48 are tilted to bring the cups into contact with the foremost blank in the magazine.

At this moment vacuum is supplied to the cups through line 69. The cups 48 attach themselves to the blank and the feed stroke of the feeder begins.

As the push rods 59 pull the

carriage

51, 56, 58 from the curved track portion 53 into the straight track portion 54, the cups 48 on their arms 49 perform a pendulous motion toward the observer, as a result of which the lower portion of the blank is pulled out of the grip of its retaining elements 1-3 and 14 at the magazine gate.

Air enters behind the withdrawn blank and the blank slides off its aligning

brackets

15, 16 and moves downward, firmly held by the cups 48.

The blank is guided laterally between the forward and the

rear guide rods

64 and 65 and crosses the path of the plunger (FIG. 3) which at this moment is retracted.

At the bottom of the feeder stroke of the

carriage

51, 56, 58 the blank comes to rest on the stop 83 and is released by the cups 48 which are vented to the atmosphere when the vent valve arm 68 strikes the bracket 82.

The adjustment of the vacuum cups 48 is such that the blank is pulled slightly toward the observer during transport, as a result of which the blank is bowed. When released the blank flattens out (FIG. 4) and leaves sufficient clearance between it and the cups 48 while the feed carrier makes its return stroke (FIG. 5).

Cam elements 84 (FIGS. 4 and 5) also assist in maintaining the delivered blank in a position away from the mouths of the upwardly moving vacuum cups 48.

During the entire feed stroke the blank is positively guided until set down on the stop 83 and there is no movement of the blank due to gravity, nor its there any .rebounding action at the stop. This insures extreme accuracy of alignment with the box forming plunger which subsequently pushes the delivered blank through the die.

In considering FIGS. 2 to 5 it will be remembered that the die was swung out of the Way, and out of the illustration, in order to show details of the feeding mechanism more clearly.

Geometry of the feeder drive Referring to FIG. 6, the centrally visible main crank 85 may be considered the principal drive element. Its shaft 92 is driven by an electric motor over a suitable reduction gear (not shown).

The crank 85 engages an oscillating beam 86 by means of a glide block 87 through which the crank pin 93 extends. The beam 86 is pivotally mounted in the machine frame at 88 and drives an oscillating input lever 89 through a connecting rod 90.

The previously mentioned oscillating arm 76 is fastened on the same shaft 91 with the input lever and rocks with it. The push rod 59 extends upwardly from the arm 76, which may also be termed output lever, and moves the feed carriage up and down.

The rock shaft 91 extends across the machine and carries one oscillating arm 76 near each end for operation of the two push rods, one oscillating arm being visible in FIG. 6, the other in FIG. 7.

The mechanics of the drive throughout its cycle of operation is best explained by reference to FIG. 9.

The crank pin 93 moves on a circle 94 on which increments C-0, C-1 through C15 are marked, the direction of rotation being indicated by the arrow 95.

It becomes at once apparent, assuming uniform velocity of the crank, that the angular velocity of the oscillating beam 86 is slower within the range from C-O to C-8, during which phase the crank pin 93 is to the right of the crank shaft 92, than it is within the range C-8 to C-0 during which phase the crank pin is on the left of the crank shaft and engages the beam 86 at a shorter lever arm. which takes place Within the range C-O to C-8 involves comparatively lower velocities than the return motion which takes place during range C-8 to 0-0.

The end 96 of the oscillating beam 86 moves on an are 97 on which increments B() through B-15 are marked, the ordinal numbers -0 to 15 corresponding to those on the circle 94.

The oscillating beam 86 drives the input lever 89 through the connecting rod articulated thereto at 98. The point 98 moves on an are 99 on which certain increments with the prefix I are marked.

It is apparent that the angular velocity of the rock shaft 91 on which the input lever 89 is mounted is considerably lower near the end position I-O in which the connecting rod 90 is substantially in line with the oscil lating beam 86 than it is near the other end position I-8 for which the connecting rod is sharply angled with respect to the beam 86 and the input lever 89.

The end 100 of the output arm 76 moves on an arc 101 identified by increment designation having the prefix A. The motion characteristics of point 100 of the output arm correspond to those of the input lever end 98, as both are fixed on the same rock shaft 9 1 and move together.

The disposition of the push rod 59 with respect to the oscillating output arm 76 is again such that for positions A-O the opposite end of the push rod at the bar 56 moves extremely slowly due to the fact that the push rod 59 is substantially in line with the output arm 76, whereas the vertical velocity of the bar 56 is greater near the opposite end A-8 of the stroke.

Considering now the motion characteristics of the

feed carriage

51, 56, 58 and of the vacuum cups, the carriage moves rapidly in an upward direction during the return stroke identified by increment numerals -8 to -l6. The carriage motion is retarded towards the upper end of the return stroke during which phase the beam 86 and the connecting rod 90' approach an in-line position and during which, further,the output arm 76 and the push rod 59 approach an in-line position.

The upward motion of the vacuum cups is additionally slowed by entry of the square transverse bar 51 into the curved portion 55 of the track 53.

During the latter phase of the feeder motion the roller 62 of the control arm 60 continues its straight upward path and causes the square bar 51 to tilt thus moving the vacuum cups 48 towards the stack of blanks B.

Considering next the withdrawal of a blank, the blank is grasped by the cups 48, whereafter their arms 49 tilt .with the square bar and pull the grasped portion of the blank away from the stack. The motion increments of the cups are identified by numerals with the prefix V.

During this phase of blank separation the cups 48 do not change their vertical position materially.

At about the position -6; '10 the mouths of the cups are in a vertical plane and the blank continues hereafter to travel the vertical path marked 10 1 and indicated by a broken line. As the blank approaches the delivery position V-8 the feeder slows to a stop and the cups come to rest when the drive crank passes through the position C-8.

It follows that the feed motion- What is claimed is:

1. A blank feeding mechanism for positively transporting a box blank from a pickup station at one level to a delivery station at a lower level, the mechanism comprising means forming a track comprising a substantially vertically extending lower portion, and an upper portion curved toward the pickup station;

a carriage movable along said track;

a vacuum element mounted on said carriage for movement in a'direction substantially transverse to the direction of said lower portion;

means operative upon entry of said carriage into said curved portion for moving said element relatively to said carriage;

drive means for moving said carriage up and down along said track;

and means operating in timed relationship with said drive means for applying vacuum to and relieving Vacuum at, said vacuum element.

2. A blank feeding mechanism for positively transporting a flat box blank from an elevated pickup position to a lower deposit position, the mechanism comprising means forming a track comprising a substantially vertically extending lower portion and a curved upper portion curved toward the pickup position;

a carriage movable along said track;

an arm tiltably mounted on said carriage;

a vacuum element on said arm;

actuating means for moving said carriage along said track, up and down;

means operative upon entry of said carriage into said curved portion for tilting said arm;

and means for applying vacuum to, and relieving vacuum at, said element in dependence on the position of the carriage relatively to said track.

3. A blank feeding mechanism for positively transporting a box blank from a pickup station at one level to a delivery station at a lower level, the mechanism comprising means forming a main track comprising a substantially vertically extending lower portion and an upper portion curved toward the pickup station;

a carriage movable along said track;

an arm tiltably mounted on said carriage;

a vacuum element on said arm;

means forming a control track adjacent said upper portion;

a follower element engaged by said control track for tilting said arm;

drive means for moving said carriage along said main track, up and down;

and means operating in timed relationship with said drive means for applying vacuum to, and relieving vacuum at, said vacuum element.

4. A blank feeding mechanism for positively transporting a box blank from a pickup station at one level to a delivery station at a lower level, the mechanism comprising means forming a track comprising a substantially vertically extending lower portion, and an upper portion curved toward the pickup station;

a carriage movable along said track;

a vacuum element mounted on said carriage for movement in a direction substantially transverse to the direction of said lower portion;

drive means for moving said carriage up and down along said track, said drive means comprising an oscillating drive arm and a connecting rod between said drive arm and said carriage, the arrangement being such that the drive arm and the connecting rod approach an in-line position when the upwardly Cir moving carriage enters said upper track portion;

5. A blank feeding mechanism for positively transporting a box blank from a pickup station at one level to a delivery station at a lower level, the mechanism comprising means forming a track comprising a substantially vertically extending lower portion, and an upper portion curved toward the pickup station;

a carriage movable along said track;

drive means including an element moving on an arc;

a connecting rod between element and said carriage, the arrangement being that said connecting rod and said element are in an in-line position when the carriage is within said upper track portion;

6. A blank feeding mechanism for positively transporting a box blank from a pickup station at one level to a delivery station at a lower level, the mechanism comprising means forming a track comprising a substantially vertically extending lower portion, and an upper portion curved toward the pickup station;

a carriage movable along said track;

means operative upon entry of said carriage into said curved portion for moving said element relatively to said carriage; i

a drive crank;

an oscillating driven arm oscillating driven arm oscillated by said drive crank;

a rocking input arm;

a first connecting rod between said driven arm and said input arm, the arrangement being such that in one terminal position of the driven arm said first connecting rod approaches an in-line position with respect to said driven arm and that in the other terminal position of the driven arm said first connecting rod extends at an angle to said driven arm;

an output arm connected to said input arm for coaxial oscillation therewith;

a second connecting rod between said output arm and said carriage, the arrangement being such that said output arm and said second connecting rod approach an in-line position when the upwardly moving carriage enters said upper track portion;

and means operating in timed relationship with said carriage for applying vacuum to, and relieving vacuum, at said vacuum element.

7. A blank feeding mechanism for positively transporting a box blank from a pickup station at one level, substantially edge first, to a delivery station at a lower level,

the mechanism comprising a substantially horizontal feed bar;

a first arm on said feed bar;

a vacuum gripper element on said first arm;

a second arm on said feed bar;

a pair of opposite main track members defining a main track in which the ends of said feed bar are guided, said main track comprising a lower substantially vertical portion and an upper portion curved toward the pickup station;

means forming a control track engaged by said second arm;

drive means including a substantially vertically disposed push rod articulated to said feed bar for moving said feed bar up and down within said lower main track portion and into and out of said upper curved track portion;

and means timed with respect to said drive means for applying vacuum to, and relieving vacuum at, said vacuum gripper element.

8. A blank feeding mechanism for positively transporting a box blank from a pickup station at one level, substantially edge first, to a delivery station at a lower level, the mechanism comprising a substantially horizontal feed bar;

a first arm on said feed bar;

a vacuum gripper element on said first arm;

a second arm on said feed bar;

a pair of opposite main track members defining a main track in which the ends of said feed bar are guided with freedom to move along the track and freedom to tilt relatively to the track, said main track comprising a lower substantially vertical portion and an upper portion curved toward the pickup station;

means forming a control track engaged by said second arm;

a second bar substantially parallel to said feed bar, the ends of said second bar being guided in said main track;

hinge means for hingedly connecting said feed bar and said second bar for movement parallel to each other in said main track;

drive means, including a substantially vertically disposed push rod connected to said second bar for moving said bars up and down along said main track including an upper terminal position in which said feed bar is within said curved track portion;

9. A blank feeding mechanism as defined in the preceding claim 8 in which the said second arm extends upwardly from said feed bar, and in which the control track is substantially vertical and extends above the level of said curved main track portion.

10. The combination with a magazine for fiat blanks comprising a gatethrough which blanks are removable from the magazine, of a feeding mechanism for removing blanks from said gate, the feeding mechanism comprising means forming a track comprising a substantially straight first portion extending in a general direction substantially parallel to the plane of a blank held in the said gate, and a second track portion curved towards said gate;

a carriage element movable along said track;

drive means for reciprocating said carriage element within and between said first and second track portions;

a vacuum element including means for applying vacuum thereto and relieving vacuum at said vacuum element in timed relationship to said drive means;

means for adjustably supporting said vacuum element on said carriage element;

and control means for adjusting the position of the vacuum element relatively to said carriage element when said carriage element is within said curved track portion.

11. The combination with a magazine for flat blanks comprising a gate through which blanks are removable from the magazine, of a feeding mechanism for removing blanks from said gate, the feeding mechanism comprising means forming a track comprising a substantially straight first portion extending in a general direction substantially parallel to the plane of a blank held in the said gate, and a second track portion curved towards said gate;

a carriage element movable along said track;

drive means for reciprocating said carriage element from said first to said second track portion, and back again; v

a vacuum element mounted on said carriage element,

whereby. a primary motion is imparted to said vacuum element towards and away from said gate by reason of the motion of the carriage element along said track;

means for applying vacuum to, and relieving vacuum at, said vacuum element in timed relationship -to the action of said drive means;

and means operative upon entry of said carriage means into said curved track portion for imparting to said vacuum element a secondary motion superimposed on said first motion.

12. The combination with a magazine for flat blanks comprising a gate through which blanks are removable from the magazine, of a feeding mechanism for removing blanks from said gate, the feeding mechanism comp-rising,

means forming a track comprising a substantially straight first portion extending in a general direction substantially parallel to the plane of a blank held in the said gate, and a second track portion curved towards said gate;

a carriage element movable along said track;

drive means for reciprocating said carriage element from said first to said second track portion, and back again;

a vacuum element mounted on said carriage element, whereby a primary motion is imparted to said vac uum element towards and away from said gate by reason of the motion of the carriage element along said track;

means for applying vacuum to, and relieving vacuum at, said vacuum element in timed relationship to the action of said drive means;

and means operative upon entry of said carriage means into said curved track portion for tilting the vacuum element relatively to said plane.

13. The combination with a magazine for flat blanks comprising a gate through which blanks are removable from the magazine, of a feeding mechanism for removing blanks from said gate, the feeding mechanism comprismg means forming a track comprising a substantially straight first portion extending at an acute angle to the plane of a blank held in the said gate and a second track portion curved towards said gate;

a carriage element movable along said track;

drive means for reciprocating said carriage element from said first track portion into said second track portion, and back again;

a vacuum element mounted on said carriage element;

means for applying vacuum to, and relieving vacuum at said vacuum element in timed relationship to said drive means;

and means responsive to the position of said carriage element with respect to said track for changing the inclination of said vacuum element from a position substantially parallel to said plane when the carriage element is within said curved second portion to a position substantially parallel to said straight first portion when the carriage element is within said first portion.

14. A blank feeding mechanism for positively transporting a box blank from a pickup station at one level to a delivery station at a lower level, the mechanism comprising means forming a track comprising a substantially vertically extending lower portion, and an upper portion curved toward the pickup station;

a carriage movable along said track;

drive means for moving said carriage up and down along said track;

vacuum supply means including a source of vacuum and a vacuum line between said source and said vacuum element;

a valve in said vacuum line;

and a movable control element movable into one of two control positions, one position corresponding to vacuum demand, the other position corresponding to no-vacuum demand;

an actuator for said valve, said actuator being mounted on said carriage in a position to move into the range of movement of said control element for actuation thereby when said carriage is in said curved portion, the arrangement being such that the actuator is engaged by said control element when the latter is in one of its two control positions and is not engaged when the control element is in the other control position.

15. A blank feeding mechanism as set forth in the 5 preceding claim 14 in which there is References Cited by the Examiner UNITED STATES PATENTS 1,980,983 11/1934 Currie 271-27 2,808,766 10/1957 Larsen 27129X 20 ROBERT E. REEVES, Primary Examiner.

S. H. TOLLBERG, Assistant Examiner.

Claims

1. A BLANK FEEDING MECHANISM FOR POSITIVELY TRANSPORTING A BOX BLANK FROM A PICKUP STATION AT ONE LEVEL TO A DELIVERY STATION AT A LOWER LEVEL, THE MECHANISM COMPRISING MEANS FORMING A TRACK COMPRISING A SUBSTANTIALLY VERTICALLY EXTENDING LOWER PORTION, AND AN UPPER PORTION CURVED TOWARD THE PICKUP STATION; A CARRIGE MOVABLE ALONG SAID TRACK; A VACUUM ELEMENT MOUNTED ON SAID CARRIAGE FOR MOVEMENT IN A DIRECTION SUBSTANTIALLY TRANSVERSE TO THE DIRECTION OF SAID LOWER PORTION; MEANS OPERATIVE UPON ENTRY OF SAID CARRIAGE INTO SAID CURVED PORTION FOR MOVING SAID ELEMENT RELATIVELY TO SAID CARRIAGE; DRIVE MEANS FOR MOVING SAID CARRIAGE UP AND DOWN ALONG SAID TRACK; AND MEANS OPERATING IN TIMED RELATIONSHIP WITH SAID DRIVE MEANS FOR APPLYING VACUUM TO AND RELIEVING VACUUM AT, SAID VACUUM ELEMENT.