US 3193282 A
Description (OCR text may contain errors)
July 6, 1965 w. A. STEWART 3, 3, 8
MECHANISM FOR FEEDING CARDBOARD 0R LIKE BLANKS Filed March 13, 1963 5 Sheets-Sheet 1 INVENTOR. WIRREN ,4. $7'EWA7I? 7' BY 79% 4 Landau;
July 6, 1965 w. A. STEWART MECHANISM FOR FEEDiNG CARDBOARD OR LIKE BLANKS Filed March 15, 1963 5 Sheets-Sheet 2 s sheets-sheet a w. A. STEWART mzcimmsm FOR FEEDING, CARDBOARD on LIKE 'BLANKS Filed March 13, 1963 July 6, 1965 July 6, 1965 3,193,282
MECHANISM FOR FEEDING CARDBOARD on L'IKE BLANKS Filed March 15, 1963 W. A. STEWART 5 Sheets-Sheet 4 INVENTOR. Wfl/PREN A. 575146497 BY a W;
y 1965 w. A. STEWART 39 9 MECHANISM FOR FEEDING CARDBOARD 0R LIKE BLANKS Filed March 13, 1965 5 Sheets-Sheet 5 dam/2% United States Patent 3,193,282 hidCHANiSM FGR FEEDING CARDBOARD 0R LIKE fiLANKS Warren A. Stewart, Monitton, Mi, assignor to Koppers Company, Inc, a corporation of Delaware Filed Mar. 13, 1963, Ser. No. 264,826 16 Claims. (Cl. 271-12) This invention relates generally to improvements in a mechanism for transferring cardboard or like blanks from one position to a second position and, more particularly, to improvements in those mechanisms for feeding blanks successively one by one from a stack thereof to processing equipment for additional treatment such as printing, scoring, slotting, folding or some combination thereof, irrespective of warp in the blank or irregularities along the edges thereof with the feeding operation being effected according to an accurate timing schedule and without skewing of the blank relative to the processing equipment.
The devices employed in the past for feeding blanks have been of three types: reciprocating feeders, vacuum feeders and reciprocating vacuum feeders. Each of the aforementioned feeding mechanisms are operable in various applications but, depending upon the nature of the blank to be fed and the degree of automation desired, each of the devices has definite limitations.
The reciprocating feeder, for example, has the inherent capacity for feeding blanks singly in successive timed relation. Further, in a reciprocating feeder the blank is engaged at substantially zero velocity thereby precluding tearing of the blank. Certain disadvantages exist, however, in reciprocating feeders: such a feeder cannot handle blanks having more than a slight degree of warp; cannot feed die-cut blanks; requires a comparatively elaborate and time-consuming set-up; requires expensive auxiliary equipment to enable feeding of overlength blanks, and by its very nature is subject to substantial reversing inertia loads, which increase power requirements and promote Wear and consequent maintenance.
Although vacuum feeders, per so, are able to handle warped blanks and blanks which have been die-cut, still other disadvantages prevail. Transport in vacuum feeders, for example, is dependent upon frictional engagement between the vacuum belts and the blank being fed and since the belts in known vacuum feeders are moving at some finite constant velocity at the moment of pickup of the blank by the belt some degree of slippage between belt and blank inevitably results. Also, because no reliable method of indexing the feeding operation of a vacuum feeder has been developed, the timing relationship for the feeding of the blanks remains inflexible rendering it incapable of successfully feeding overlength blanks. On the other hand, the simplicity of the method of contact with and transport of the blanks by the vacuum feeder mechanism minimizes the complexity of the set-up, because neither spring feeder bars nor backstops, both of which are required in reciprocating feeders, are needed. And, since there are no reversing inertia loads, such a device can be made of lighter construction and is less subject to car than one of the reciprocating variety.
An outgrowth of the purely reciprocating-type and purely vacuum-type feeders is the last of the three types, the reciprocating vacuum feeder, which device attempts to incorporate the advantages of both the previously discussed devices. However, in spite of the distinct advance made by the reciprocating vacuum feeder over the earlier devices, this device is still subject to the application of heavy double frequency reversing inertia loads inherent in a reciprocating feeder. Also, the application of suction must be in timed relationship with the reciprocating movement of the feeder and consequently the parts which effect this intermittent application of suction are susceptible to considerable Wear and require a disproportionate amount of maintenance. In addition, backstops must be used in conjunction with such a device to prevent the blank, which is awaiting pickup by the feeder, from being misaligned during the backward stroke of the feeder.
In other respects, the reciprocating vacuum feeder is an advantageous marriage of the previously discussed feeders, since it has an inherent timed activity, has a period of zero velocity during which to engage the blank to be transported; is capable of feeding warped blanks in a positive manner and requires shorter set-up time than does a reciprocating feeder due to its relative simplicity.
it is, therefore, an object of the present invention to provide a non-reciprocating mechanism for transporting cardboard or like blanks from a first to a second position at high speed employing a continuously applied vacuum to periodically couple the transporting element, which is driven in a cycle of non-uniform velocity, to succeessive blanks at rest in the first position wherein initiation of the coupling action occurs during a period when the transporting element has a small or zero velocity.
It is another object of the present invention to provide a method for feeding blanks one at a time in a consecuport element; accelerating the transport element and the blank to a given board speed; maintaining the velocity of transport element and blank at this board speed while the blank is conducted to a subsequent processing operation and decelerating the transport element to frictionally engage the succeeding blank at zero velocity.
It is a further object of the present invention to provide a simple means selectively operable to provide reliable feeding of overlength blanks (skip feeding).
It is still another object of the present invention to provide a non-reciprocating feeding mechanism for blanks employing a continuous vacuum and engaging successive blanks substantially at zero velocity wherein a minimum of rearranging of parts is required to set-up for a different blank size and to provide for the feeding of either underlength or overlength blanks.
The above objects are secured in accordance with this invention by employing in combination a pair of side frames supporting a bed for receiving a pile of blanks, side guides to locate the pile of blanks laterally of the bed, a vertically extending gate aligning the front of the pile of blanks and limiting the feeding action to the passage thereby of one blank at a time, means moving in a path describing a single closed curve for receiving and trans porting in timed sequence individual blanks from the pile of blanks; means for positively, sequentially receiving the individual blanks from the transporting means, while these blanks are traveling at high speed, means for driving the transport means in a cycle of non-uniform velocity, means for continuously applying a vacuum to the underside of the transport means, said transport means having groups of apertures spaced along its length whereby a vacuum is introduced sequentially between said transport means and a substantial portion of the surface of individual blanks in the pile of blanks resulting in vacuumcoupling of the blank to the transport means whenever a group of apertures is brought into juxtaposition with the pile of blanks during a period of relatively low or zero velocity of said transport means. 7
ther objects and features of the invention will become apparent to those skilled in the art as the disclosure is made in the following detailed des ription of a preferred embodiment of the invention as illustrated in the accompanying sheets of drawings in which:
FIG. .1 is an isometric View showing the general arrangement of the side frames, bed, driving mechanism, pull rolls and the vacuum feeder assembly,
FIG. 2 is an isometricview similar to FIG. 1 with portions thereof cut away to show the interior details city of the vacuum belt as a function of blank displacement.
A preferred embodiment of the feeding equipment is shown in FIGS. 1 and 2 wherein feeder comprises a pair of spaced side frames 11 and 12 serving to support the substantially flat portions comprising the bed 13, horizontally disposed rail 14 and horizontally disposed, rotatably-mounted upper and lower pull rolls 1% and 17 respectively, the pivotally-mounted vacuum assembly 18 (to be described in greater detail below) and the various components for receiving and transmitting the driving force for feeder It) from motor 19.
In this embodimentblanks are removed one by one from the bottom of pile 21 by vacuum assembly 13 and are positively fed in timed sequence and at board speed through the gap between the surface of bed 13 and the underside of gate 22 mounted in holder 23, which is in turn slidably supported on rail 14. Although only one-gate 22. is disclosed, a greater number may be em ployed. It is important that gate 22 be properly adjusted relative to the surface of bed 113 to permit the passage -of only one blank at a time for this enables operation of 'the feeding device without jamming.
As the front edge of any given'blank is moved past gate 22, it is shoved with a positive delivery action by vacuum feeding mechanismrit' between pull rolls X6 and 17, which rolls grip the blank firmly and pass it on into the adjacent equipment at board speed after having received the blank at board speed from vacuum feeding mechanism 18.
When feeder it) is being set up for a run of a given size of blanks, the lateral positioning of the pile of blanks 21 is set by locating the side guides 24, which engage the leading corners of pile 21, along railld and fixing the positions of side guides 24 by means of suitable screws 26. I-lolder 23 is located along rail 14 as desired and is fixed in position by tightening clamping screw 27. Then gate 22 is vertically adjusted to define the opening between the surface of bed 13 and the underside of gate 22, which opening is substantially the same size as the thickness of each of the blanks in pile '21. This adjustment is accomplished by means of turning screw 28, whereby gate .22 is caused to move up or down.
Actually, adjustment of gate 22 need be made for only an initial thickness of blank, since provision is made for simultaneous vertical adjustment'of upper pull roll 16, gate-22 and side guides 24. Thus, on the first set-up roll 16' is positioned vertically to leave a space between'lower pull roll 17 and upper pull roll 16 substantially the same as thethickness of the individual blank to be transported.
modate this thickness. Thereafter the space between the rolls l6, 17 is made larger or smaller to accommodate ditferent runs or blanks by rotating shaft 2.9 in the proper direction whereby pinions 31, one of which is fixed to each end of'shaft 29, are rotated and revolve in turnthe eccentric housing 32 within which pull roll 16 is mounted. The movement of eccentric housings $2, and thereby of roll to, is effected since the outer diameter of housing 32 has gear teeth formed thereon which mesh with the teeth of pinions 31. The axis of pull roll 16 is mounted eccentric to the axis of housings 32 and as housings 32 are revolved the axis of the pull roll 15 travels in an are about the axis of the housing thereby raising or lowering the pull roll 16 as desired. Since rail 14 is slidably mounted in side frames 11 and 12 and is rigidly mounted to housings 32 by means of connectors 33 at either end of rail 14, rotation of the'outer diameter of housings 32 in addition to vertically repositioning pull roll 16 also repositions rail 14 and, thereby, gate 22 and side guides 24. Thus, once the passage defined by the gate 22 and the surface of bed 13 has been determined in relation to the space between pull rolls 16 and 17, a single adjustment serves to reset both the pull roll 16 and gate 22 for the blank thickness of a new pile of blanks 21.
plicity a single belt 35 is shown, a number of bolts are normally employed to transmit the power from motor 19. At the near end of pull roll 17 as seen in FIG. 1
is mounted gear 3% in mesh with-gear 39 affixed to shaft 41 of pull roll 16. a
In practice a constant mesh coupling (not shown) is employed between gears 38 and 39 to accommodate the changes in position of gear 59 when pull roll 16 is reset vertically as described above. Thus, motor 19 serves 'to drive both lower pull roll 17 and upper pull roll 16.
Also, in the embodiment shown, provision is made for driving mechinery (not shown) adjacent to feeder 1% via idler gear 42 mounted on stub shaft 43 and gear 44 in mesh therewith. Power for the mechanical operation of the vacuum assembly 18 of feeder 10 is supplied to gear 45 via idler gear 47, gear 46 being mounted at one end of shaft'dfi supported in a bearing (not shown) in side frame 11 and in bearing 49 mounted on base $1. Mounted on the distal end of shaft 48 is bevel gear 52in driving arrangement with bevel gear 53 mounted on shaft 54. Shaft 54 is rotatably supported in bearings 56 and 57 in the end walls of gear guard 58 having mounted thereon and affixed thereto a cam 59 such as Ferguson cam shown and described in the Ferguson Machine Company Catalog No. 161 (Second Printing) entitled Indexing and Transfer or some suitable modification thereof.
In the embodiment disclosed herein gear 38 and bevel gear 53 are designed in a particular ratio to each other in order that shaft 54 and thereby cam 5'9 will make one complete revolution during the cycle of feeding of each blank from pile 21. Cam follower assemblage s1 comprisesra plurality of bearing-mounted follower rollers 62 mounted on hub 63 for rotation around their individual central axes, hub es in turn being affixed to shaft 6%.
Cam 59 and follower fil are so designed that as cam 59 is driven at a uniform angular velocity, a non-uniform angular'velocity is imparted to cam follower 61 including a period of acceleration, a period of constant velocity, a peri- 0d of deceleration and a period of zero velocity dwell during each delivery cycle, while cam 59 continues to rotate at uniform angular velocity. The particular sequential perimunication with vacuum trough 96.
mounted on shaft 64 and is driven thereby whenever cam follower 61 is rotated by cam 59 and gear 67 in turn drives gear 68 afiixed to the end of the belt drive shaft 69 rotatably supported in bearings at the far ends thereof set in side frames 11 and 12. Pulleys 71, which are preferably cleated timing belt pulleys, are each affixed to shaft 69 at spaced positions along shaft 69 as shown and are the driving elements for the transport function of vacuum feeding assembly 18.
Vacuum housing 72 with parallel end plates 73 affixed along the far sides thereof or formed integral therewith comprises the structural core of assembly 18 and is pivotally supported on belt drive shaft 69 via bearings in one end of each of end plates 73. All elements forming vacuum feeding mechanism 13, other than the pulley 71, are supported by vacuum housing 72. Shaft 74, which is parallel to shaft 69 is mounted at each end thereof in bearings in end plates 73 and has securely affixed thereto spaced pulleys 76 similar to pulleys 71 and located along shaft 74 in alignment with pulleys 71. Spaced internal support plates 77 are disposed substantially parallel to end plates 73 and these plates 77 together with end plates 73 serve to support pulley adjustment shaft 78. Pivotally mounted on shaft 78 is yoke 81, which supports a pulley 82 similar to pulleys 71 and 76, and yoke 83 which supports pulley 84, the mate to pulley S2. Adjusting screws 85 and 86 are employed to position the depending pulleysupporting ends of yokes 81 and 83 relative to pulleys 71 and 76 by the coaction of these adjusting screws threaded through the arms of yokes 81 and 83 respectively with the abutments 87 and 3S, abutment 87 being rigidly connected between internal support plates 77 and each of abutments 38 being bosses formed on end plates 73. In this fashion when viewed from a direction parallel to shafts 69 and 74, two sets of three pulleys each (71, 75, 32 and 71, 76, 84 respectively) are seen so arranged that the axes of rotation of the pulleys comprising each of the sets will form the three corners of identical triangles.
Each set of three pulleys are in alignment and are encircled by the cleated endless belts 89 driven by their respective pulleys 71. Driven belts 89 in turn drive pulleys 76 and 32 and pulleys 76 and 84. In the event that cleated pulleys and belts are employed, as shown, additional assurance is provided that there will be no slippage between belt and pulley, ecause of the positive drive characteristics of such an assembly. lroper tension is maintained in belts 39 by taking up or releasing adjusting screws 85 and 36 as required.
In the particular embodiment disclosed, each belt 39 has a perimetric length of 80 inches over the extent of which two groups of apertures or perforations 91 are provided, each of which groups extend over 29 inches of the belt 39 and in alternating relationship with two unperforated 20 inch lengths of belt.
As shown in FIG. 1 the upper run of each belt 89 traverses under pile 21. In order to provide positive engagement between the upper run of each belt 89 and the bottom most blank in pile 21 provision is made for vacuum coupling therebetween employing a constantly active vacuum system arranged to be placed in register with the bottom-most blank via perforations 91 according to a given cycle of operations.
The vacuum inducing system comprises a central plenum 92 in housing 7 2 disposed between the two internal su port plates 77, which plenum 92 communicates via flexible duct 93 with a powerful constantly operating suction-inducing vacuum pump 94 on the one hand and, on the other hand, communicates with a pair of shallow vacuum troughs 96 disposed to either side thereof and projecting between upper and lower runs of belts 89 via passages 97 penetrating the internal support plates 77. The upper run of each of belts 89 passes over one of the vacuum troughs 96 so that periodically one or the other of the groups of perforations 91 in each belt 89 is placed in com- Belts 89 are co- 6 ordinated so that registry between thegroups of perforations 91 and the respective vacuum troughs 96 is simultaneously effected during the cyclic traverse of belts 89. Pump 94- must have a rate of withdrawal of air from the suction system to compensate for air leakage between the cleats of belts 89.
As may be seen from the drawings primary support for the entire vacuum feeding assembly 18 is forthcoming from belt drive shaft 69, since plates 73 are pivotally sup ported thereon whereby all of vacuum assembly 18 framed to and supported upon end plates 73 may be pivoted about shaft 59 as center.
The pivoting of vacuum assembly 18 is effected by the interengagement of either cam 93 with follower 99 or of cam 191 with follower H92 in the manner to be described below. Both cams 98 and lltll are fllfiXfZd to cam shaft Ill-3, which shaft is in turn bearing-mounted in end plates 73, with cam shaft 193 extending through the right hand end plate 73 to accommodate the mounting thereon of a third cam 1M adapted to coast with cam follower 106. Cam shaft 103 also extends to the left through end plate 73 for eventual connection with shaft 54 (details not shown) to provide continuous rotation of cam shaft 193 at uniform velocity. In FIGS. 2, 3 and 4 sequential relative positioning of cam 93 and follower 99 and the consequent changes in attitude or" vacuum assembly 18 produced relative to bed 13 are shown.
With the disposition of parts shown, as continuously rotating cam shaft Hi3 turns, cam 93 is rotated and its face is held in contact with cam follower 99 by the action of biasing compression springs 107, which force the otherwise unsupported end of vacuum assembly 18 upwardly toward bed 13 in a manner obvious from the drawings. As the surface of either of the two lobes ms, 109 of cam 98 coact with follower 99, the right hand end of vacuum feeding assembly 18 as shown in FIG. 3 is forced downward relative to bed 13 below the upper surface thereof against the force of biasing springs 167, the entire feeding assembly 18 being pivoted about drive shaft 69. When cam 98 has been rotated so that the surface of the highest portion of either lobe 138 or lobe 109 has passed through its period of contact with cam follower 99, springs 1G7 operate to bias the vacuum assembly 18 upward to ulti mately reach the position shown in FIG. 3 relative to stationary bed 13. In this position vacuum assembly 18 may be slightly raised (about at its outer end above the upper surface of bed 13 to promote better contact between the belt 59 and the bottom blank of pi e 21. Since lobes 198 and 169 are arranged on cam 98 apart, the flexibly supported end of Vacuum assembly 18 will be pivoted up and down twice during each revolution of cam shaft 163.
As has been described above, both drive shaft 69 and cam shaft 103 receive their power from shaft 54 whereby the rotation of these shafts relative to each other can be predetermined. Thus, although the rotation of drive shaft 69 and consequently of belts 89, is effected with a non-uniform velocity, the operation is executed in accordance with an established cycle, the pivotal movement of vacuum assembly 18 being interrelated with the movement of belts 89 so that, while cam 98 and follower 99 are operative, vacuum assembly 18 is raised and depressed two times for each complete traversal of bolts 89.
Depending on the proportions of the equipment to which the blanks from pile 21 are delivered, a normal range of lengths of blank can be handled with the arrangement described. Length in this case is the term applied to the dimension of the blank extending from its contact with gate 22 to the far end of the blank in the direction of travel of the blanks.
For skip-feeding, an optional operation for vacuum feeding assembly 18 when overlength blanks are fed from pile 21, the interrelationship of the raising and lowering of vacuum feeding mechanism 18 relative to the cyclic operation of drive shaft 69 and belts 89 is altered by deactivating cam and follower combination 1%, 99 and activating in its stead the combination of cam 1111 and cam follower 102. This rearrangement is efiected by turning knob 111, which causes sprocket 112 mounted on a shaft common to these two elements to rotate, thereby rotating sprocket 113, which is connected to sprocket 112 by endless chain 114. Sprocket 113 is afiixed to shaft 116 rotatably mounted in bearings (not shown) in stationary members 117 and 11S supported by and afiixed to bed 13..
Stationary member 118 is essentially U-shaped and receives shaft 116 in both depending leg members as shown in FIG. 3. Although that portion of shaft 116 spanning between the depending leg portions of stationary member 118 is threaded, the holes in thedepending leg portions of stationary member 118 are not threaded. Thus shaft 116 is freely rotatable relative thereto and also relative to stationary member 117 at the opposite end thereof.
Threadably engaged with the threaded portion of shaft 116 is the cam followerrtrolley 119, which element has a main body portion 121 from which depends integral central web portion 122 on which are bearing-supported cam followers 9% and 1112. Shoulder portions 123 are slidably supported on side bars 124, which are disposed parallel to shaft 116 and span between the depending leg portions of stationary member 118 being amxed thereto as by welding. As shown the top and sides of trolley 119 are retained by rigid, stationary surfaces contiguous therewith. In this fashion, as shaft 116 is provided with the proper rotational sense, trolley 119 may be moved to the left or to the right (as seen in FIG. 3) within the confines of stationary member 118 to place either cam follower 99 or cam follower 102 in a position vertically above cam shaft 163 and thereby placing either cam 98 or cam 101 into engagement with its companion cam follower.
Thus, to accommodate the feeding of overlength blanks, trolley 119 is advanced to locate the axis of cam follower 102 directly over the axis of cam shaft 103. Thereafter, vacuum feeding assembly 18 will be lowered and raised but one time during each revolution of cam shaft 193 and but once during each complete circuit'of belts S9 for, as is illustrated in FIGS. 2 and 4, cam 101 has but a single lobe 126. Lobe 126 comprises the greater part of the perimeter of cam 1131, however, and retains assembly 18 in its lowered position for the greater part of each com-' plete circuit of belts 89. The manner in which this change provides for skip-feeding will be explained in greater detail below in connection with the operation of this invention.
As has been explained above, two spaced 20 inch lengths of each belt 89 are perforated and when either one of the perforated portions is disposed in juxtaposition beneath the pile of blanks 21 in .register with a vacuum trough 96, the constantly-applied suction becomes effective to vacuum couple the bottom-most blank of pile 21 to the belts 89 for delivery. However, in the event that the blanks to be transported are shorter than 20 inches in length, special provisions must be made so that a vacuum will be created between each belt 39 and the bottom-most blank. There are two alternatives, either a powerful enough pump 94 can be employed to create sufiicient suction to withdraw air from vacuum troughs $6 at a rate in excess of the rate of admission of air through the holes in the perforated portion of the belt 89 not covered by the short blank or a cover (not shown) extending across belts 39 and supported on bed 13 may be used to cover those holes remaining open when a group of perforations 91 is in juxtaposition with the underside of pile 21. V
The auxiliary equipment employed for etfectuating the feeding of blanks less than 20 inches long comprise a pair of rails 127 located to the far sides of the end plates 73, each of which rails 127 is pivotally supported at one end thereof from a stub shaft projecting from the far side of each end plate '73 in the vicinity of drive shaft 6 9; "Near theother end of each of rails 127 is cam follower 106 rotatably-mounted on rail 127 with its central am in a poshaft 1613 so that the two lobes 129, 131 of cam 1114 are angularly offset from the lobes 1118,1119 of cam 98.
In this manner the pivoting action induced in rails 127 relative to vacuum feeding mechanism 18 does not coincide with the pivotal movement of mechanism 18 relative to bed '13. This angnlarly offset positioning provides for a time lag whereby when the bottom-most short blank has been coupledyto the belts 89 and has been advanced approximately 8 inches, rails 127 will be pivoted to raise upwardly and pads 132 will engage the bottom of pile 21 and as pads 132 continue to move upwardly supporting pile 21 (other than the blank being fed) the belts 89 continue to transport the bottom-most blank until this hottom-most blank has been moved adistance of 20 inches. At this point the perforated portion of the upper run of each belt 89 has moved out of register with its respective vacuum trough 96 so that there is no possibility of engaging the front edge of the next succeeding blank and only one blank can be fed by any given group of perforations on the belts 89.
After the period during which the 20 inches of displacement has occurred, cams 164 permit rails 127 with pads 132 attached thereto to descend and lower pile 21 to rest upon bed 13 awaiting the next feed cycle. Simultaneously with this lowering of pile 21 the entire feeding assembly 18 is simultaneously lowered below the surface of bed 13. In this fashion it is assured that belts 89 cannot engage the bottom-most of the short blanks until assembly 18 has once again been raised to the position shown in FIG. 3 with a group of perforations 91 in juxtaposition between vacuum troughs 96 and the bottom-most along rails 127 and, since pads 132 are not required when blanks longer than 20 inches are being fed, they are easily removed from rails 127 so as not to interfere with the feeding of longer blanks.
.The operation of transporting blanks of regular-length is best described in connection with the graphic representatlon in FIG. 6 wherein the non-uniform velocity of belt 89 during one revolution of cam 59 is plotted having superimposed therein the periods of descent and ascent of assembly 18 during this cycle. As a matter of design the proportions of the feed mechanism 10 are definitely related to the proportions of the elements of the adjacent equipment, which is to perform additional operations on the transported blanks; such as by way of example, a printing drum (not shown). A typical printing drum would be 50.023 inches in circumference and would be rotated at an angular speed equal to a circumferential velocity of 183.416 inches per second. In order to apply printing in register to the blanks fed thereto, it is well-known that the blank must be fed into the printing station in a given timed relation to the circumferential velocity of the printing drumrto wit, at 183.416 inches per second. V
The circumference of the printing drum is determinative of the length wihch may be termed standard or regular. In the example cited above, since the circumference of the printing drum expressed in round numbers is 50 inches, the theoretical length of blank which can be fed with thexleading edge of one blank following erate the blank from zero velocity at the stack to the requisite board speed of 183.416 inches per second without slippage to be delivered to the printing station in register. Acceleration of the blank from Zero velocity to the requisite 183.416 inches per second can be effected by vacuum belts 89 in .0272 second. During this initial .0272 second the average speed of the blank is 12 183.416 inches per second and the distance actually traveled is 2/2 inches. Thus, after .0272 second, the leading edge of the blank will trail the theoretical displacement (5 inches) by 2 /2 inches with the result that the maximum length blank which can be fed without skip feeding is 47 /2 inches; that is, the 50 inch theoretical length minus 2 /2 inches, which is the displacement required to accelerate the blank to board speed.
During the first 2 /2 inches of displacement the blank is brought to board speed (183.416 inches per second), then the velocity is held constant at this value for an additional displacement of 17 /2 inches. Since the perforated portions of belts 89 are 20 inches in length, at the end of 20 inches of displacement of the blank being delivered, the perforated portion of each of belts 89 will have completely passed over its respective vacuum trough 96 and the unperforated portions of the belt will be in juxtaposition between the underside of the pile 21 and suction troughs 96, whereupon the suction in vacuum troughs 95 is rendered ineffective for vacuum coupling.
At this point in the cycle of operation, one or the other of lobes 108, 109 of cam 93 will be beginning its contact with follower 99 during which vacuum feeding mechanism 18 will be lowered gradually so that belts 89 are moved out of contact with the pile 21 of blanks and no portion of the surface of belts S9 protrudes above the bed 13. When the high point of lobe 1158 or 109 is in contact with cam follower 99 the relative positioning of assembly 18 and bed 13 will be as shown in FIG. 4. In the period of the operating cycle during which assembly 18 is being lowered, the belts 39 are being decelerated by cam 59 and follower 61 and at the time the high point of lobe 108 or 109 is in contact with follower 99 the belts 89 will have almost stopped. By the time the down slope of the lobe 198, 16? is in contact with follower 99 so that the assembly 18 will have begun to rise to its transport position, belts 89 will have come to rest and will remain at zero velocity during the upward swing of assembly 18 until belts 81 will have reached the level of the upper surface of bed 13. If desired assembly 18 can be moved about /8 inch at its outer end above the upper surface of bed 13, a distance sufiicient to lift the pile of blanks 21 a slight distance to insure maximum friction contact between the surface of belts $9 and the bottommost blank of pile 21.
At the instant that belts 89 stop they will each have passed through a displacement of 40 inches. Since the belts 89 are no longer in contact with the underside of pile 21 during the deceleration period, the rate of deceleration is unimportant and the two dotted lines of different slopes represent the range over which acceptable rates of deceleration may be designed.
When the blank itself has been displaced 45 inches from its original position, assembly 18 will have reached its original raised position with belts $9 at rest. When the maximum length blank (47 /2 inches long) is being fed, therefore, the suction from the second group of perforations will apply itself to grip the last 2 /2 inches of the blank previously fed, but this should have no detrimental effect, since at this time this blank will be moving at board speed and be under the positive control of not only the pull rolls 16, 17, but also, at least one set of the rolls (not shown) in the adjacent equipment.
In the case of feeding over-length blanks (in the present description a length of blank longer than 47 /2 inches) the previously described relocation of trolley 119 is effected by rotating knob 111 so that the axis of cam 191 is directly above the axis of cam shaft 1113. With cam 101 and follower 1132. active, assembly 18 will be raised and lowered only once for every two revolutions of the printing drum in the adjacent equipment and only one blank will be fed for every complete traverse of belts 89. Thus, although the velocity cycle of belts 8? will not vary from FIG. 6 'or other such established cycle, vacuum assembly 18 will be in the raised position only one time during each complete traverse of belt 89.
It may be readily appreciated that by feeding only one blank for every two revolutions of a 50 inch diameter printing drum it is theoretically possible for feeder 16' to feed a 97 /2 inch long blank although in practice this length seldom exceeds 62 inches because of the limitations of the present day equipment receiving the blanks for subsequent treatment.
In the feeding of blanks less than 20 inches long, pads 132 are secured to rails 12? and cams 1% are angularly positioned relative to the two-lobed cam 98 to provide the desired lag time so that as the bottom-most blank from pile Z1 is being fed and has been displaced by approximately 8 inches from pile 21, the lobes 129 or 131 of cam 1154 will raise rails 127 and pads 132 above the level of the upper surface of belts 89. Pads 132 engage the bottom of the pile 21 but do not contact the displaced bottom-most blank, and support pile 21 during the subsequent displacement of the bottom-most blank for the period until this blank has been displaced a total distance of 20 inches. In this manner only the bottom-most blank will be fed by each of the groups of perforations 91 in belts 39.
After the 20 inches of displacement of the bottom-most blank referred to above has occurred, cams 194 permit rails 127 with pads 132 attached thereto to lower the pile 21 to rest upon bed 13 awaiting the next feed cycle. As shown in FIG. 6, by this time assembly 18 will have started its downward motion and belts 89 are being depressed below the surface of bed 13 so that there can be no engagement between belts 39 and the bottommost blank of pile 21 until belts 89 are again raised to their upper position.
Without the use of this auxiliary equipment, once a blank less than 20 inches long has been fed, the next blank could fall down against belts 89 and the remaining extent of the group of perforations 91 projecting beyond the preceding blank would grip the subsequent blank and cause it to be fed directly after the preceding blank on the same feed cycle and the subsequent blank would be out of register. Also, the subsequent blank would not be vacuum coupled with belts 89 when belts 89 are at rest, a most important feature of this invention.
Thus, by employing a uni-directional feeding motion in combination with frictional coupling action between belt and blank at zero velocity and by employing a continuous application of vacuum rather than utilizing a mechanical make and break device, the embodiment of the invention disclosed herein does for the first time successfully combine the advantageous features of the reciprocating feeder with those of the timed vacuum feeder.
Although a particular cam and follower has been employed for elements 59 and 61, the invention is not to be restricted to the use of a specific motion generating drive, but any device receiving a uniform velocity rotational input but having an output of non-uniform velocity, such as a Whitworth drive may be employed as long as it produces the velocity characteristics desired in the performance of this invention.
Depending on the mechanism to receive the blanks from feeder 10 various length belts 89 would be used and even multi-lobed cams with more than two lobes would be employed to accommodate the chosen number of groups of perforations in belt 89, but in each instance the feeder belt would advance in one direction only with the vacuum coupling being effected at or about zero velocity.
As enumerated above various modifications may obviously be resorted to by those skilled in the art without departing from the spirit and scope of the invention, as hereinafter defined by the appended claims, as only a preferred embodiment thereof has been disclosed.
i (d) suction means operating through the perforated section for vacuum coupling the one sheet to the conveyor belt whereby the sheet is movable with the belt; and (e) an adjustable stop for restraining all of the sheets in the stack against lateral movement except the one sheet, whereby the one sheet is laterally moved by the conveyor belt during the motion of the'belt. 2. A mechanism for feeding a sheet from a stack of sheets comprising:
(a) a stationary substantially horizo'ntal bed adapted to support said stack of sheets;
(b) an endless conveyor belt mounted adjacent the horizontal bed and having a perforated section; (c) means for cyclically advancing the conveyor belt toward and away from the stack of sheets, said conveyor belt moving unidirectionally through a non-uniform velocity cycle having a finite period of zero velocity as indicated in FIG. 6 where said belt contacts one of the said sheets;
((1) continuous suction means operating through the perforated section for vacuum coupling the one sheet to the belt during the period of zero velocity and for a period of time thereafter during the nonuniform velocity cycle; and l V (e) an adjustable stop for restraining all of the sheets in the stack against lateral movement except the one sheet which is laterally movable with the conveyor belt. 7
3. A mechanism for feeding a sheet from a stack of sheets comprising:
(a) a stationary substantially horizontal bed'adapted to support said stack of sheets; 7 l
(b) an endless conveyor belt pivotally mounted adjacent the horizontal bed and having a perforated section;
(c) means for advancing the conveyor belt unidirectionally through a non-uniform velocity cycle having a finite period of zero velocity wherein the belt contacts one of the sheets, and cyclically toward and away from the stack of sheets in synchronism with the non-uniform velocity cycle;
((1) continuous suction means operating through the perforated section for vacuum coupling the belt to one of the sheets during the period of zero velocity and thereafter accelerating the sheet to a predetermined velocity; and
(e) an adjustable stop for restraining all of the sheets in the stack against lateral movement except one sheet whereby the one sheet is movable laterally with the conveyor belt. r
4. A mechanism for feeding a sheet from a stack of sheets comprising:
(a) a stationary substantially horizontal bed adapte to support said stack of sheets; 7
('b) a plurality of conveyor belts each pivotally mounted adjacent the horizontal bed andeach having atleast one perforated section;
(c) means for simultaneously advancing said belts 12 unidirectionally, each belt moving with a non-uniform velocity cycle having a period of acceleration, a period of uniform velocity, a period of deceleration and a period of zero velocity as indicated injFlGi6, each v said beltmoving simultaneously with the other belts toward and away from the stack of sheets in cyclical motion and in synchronism with the non-uniform velocity cycle;
(d) continuous suction means operating through the perforated section of each belt for vacuum coupling each of said belts to one of said sheets during the period of zero velocity; and V (e) an adjustable stop for restraining all of the sheets inthe stack against lateral movement except the one sheet which is movable with the conveyor belts during the non-uniform velocity cycle. 5. A mechanism for feeding a sheet from a stack of sheets comprising: 7
(a) a stationary substantially horizontal bed adapted to support said stack of sheets; a
(b) an endless conveyor belt having a pair of spaced apart perforated sections and being pivotally mounted adjacent the horizontal bed; a g
(c) means for advancing said belt unidirectionally through two non-uniform velocity cycles during each revolution of the belt, each non-uniform velocity cycle including a period of belt acceleration, a period of uniform belt velocity, a period of belt deceleration and a period of zero belt velocity;
((1) means for moving said conveyor belt cyclically toward and away from the stack of sheets in synchronism with the non-uniform unidirectional movement of said belt, whereby during each period of zero velocity a perforated sect-ion of the belt contacts one of the sheets of the stack; a
(e) continuous suction means operating through the perforated section of the belt which is in contact a with the sheet whereby the sheet is vacuum coupled to the conveyor beltnand is movable therewith; and
(f) means for maintaining the stack of sheets in a fixed lateral position and allowing only one sheet at a time to become vacuum coupled to said belt during each period of contact and move laterally with the belt.
6. A mechanism for feeding a sheet from a stack of sheets comprising:
(a) sheet advancing means capable of contacting one sheet at a time of said sheets;
(0) continuous suction means capable of vacuum coupling said sheet advancing means to said one sheet; (c) means for moving said sheet advancing means unidireotionally through a non-uniform velocity cycle as indicated in FIG. 6 during which said sheet advancing means is vacuum coupled to said sheet while said sheet advancing means is moving linearly at zero velocity;
(d) means for accelerating said sheet and sheet advancing means and releasing said sheet after the same has reached a uniform velocity; and
' (e) means for decelerating said sheet advancing means to zero velocity. V 7. A mechanism for feeding a sheet from a stack of sheets comprising: 7 V
(a) an endless sheet advancing belt capable of moving 7 unidirectional-1y.through more than one non-uniform velocity cycle during each rotation of said belt, with each non-uniform velocity cycle having a period of zero velocity as indicated in FIG. 6;
(b) continuous suction means for vacuum coupling saidsheet advancing means to one of said sheets at a time during each period of zero dwelltand' thereafter during each cycle accelerating said one sheet to a uniform velocity; and
(c) means for releasing saidsheet and decelerating said sheet advancing means during each cycle.
8. A mechanism for feeding a sheet from a stack of sheets comprising:
(a) an endless sheet advancing belt capable of moving unidirectionally through a non-uniform velocity cycle during each rotation of said belt with said velocity cycle having a period of zero velocity as indicated in FIG. 6; V Y
(b) continuous suction means for vacuum coupling said sheet advancing means to one of said sheets at a time during said period of zero velocity and thereafter during the cycle accelerating said one sheet to a velocity and maintaining the one sheet at a uniform velocity for a finite period of time; and
(c) means for releasing said sheet and decelerating said sheet'advancing belt during the cycle.
9. The combination with (a pair of pull rolls and a stack of sheets of a mechanism for feeding one sheet from said stack comprising:
(a) an endless conveyor belt periodically engageable with one said sheet and capable of moving said sheet toward said pull rolls with a non-uniform velocity as indicated in FIG. 6, said belt being vacuum coupled to said sheet during the period of zero velocity of said belt.
14). A mechanism for feeding sheets from a stack comprising:
(a) a stationa-l substantially horizontal bed adapted to hold a plurality of sheets;
(b) an endless conveyor belt mounted adjacent said bed and having a perforated section;
(c) means for advancing said conveyor unidirectionally through a non-uniform velocity cycle having a period of zero velocity;
(d) means for pivoting said conveyor belt toward and away from said sheet at least once during each rota tion of said belt, with said perforated section contacting one sheet at a time during the period of zero velocity;
(e) continuous suction means operative through said perforated section for holding said sheet against said conveyor and moving the sheet with said belt; and
(f) means for holding all but one of said plurality of sheets whereby only one sheet is moved laterally by said conveyor at one time.
11. The invention set forth in claim 1% wherein the means for advancing said conveyor through a non-uniform velocity cycle having a period of zero velocity includes a powered cam and follower mechanism.
12. A mechanism for feeding a sheet from a stack thereof, comprising:
(a) an endless conveyor belt having a perforated section;
(b) means for advancing said conveyor belt unidirectionally through a non-uniform velocity cycle having a period of zero velocity;
() means for cyclically moving said conveyor belt toward and away from said stack in synchronism with said non-uniform velocity cycle whereby during the period of zero velocity said perforated section contacts one of said sheets;
(d) suction means operative through said perforated section for holding said sheet against said conveyor, said sheet moving with said belt as it thereafter accelerates to a uniform velocity; and
(e) means for holding all but one of said plurality of sheets in a fixed lateral position whereby only one sheet contacts and moves with said conveyor belt at one time.
13. A method for removing one sheet from a stack thereof and transporting the sheet, comprising the steps of:
(a) moving an endless conveyor belt having a perforated section from a first position to a second position adjacent said stack so that the perforated section contacts said one sheet during the time said belt is moving linearly with zero velocity, and the perfo,
' rated section is in communication'with a suction station;
(b) continuously applying suction to said perforated section to vacuum couple said sheet to said belt;
(c) accelerating said belt and said sheet linearly to a velocity;
(d) maintaining the velocity of the sheet and belt at a uniform value during the period of time that said belt moves from said second position to a third position and said perforated section moves away from said suction station whereby said sheet is released from said belt; and
(e) moving said belt from said third position to said first position while said belt decelerates to the initial zero velocity.
14 A method for removing one sheet from a stack thereof and transporting the sheet, comprising the steps of:
(a) moving an endless conveyor belt having a plurality of spaced apart perforated sections from a first position to a second position Where a first perforated section contacts one sheet during a period of time when said belt is moving linearly at zero velocity and the first perforated section is in communication with a suction station;
(b) continuously applying suction to said first perforated section to vacuum couple said sheet to said belt;
(c) accelerating said belt and said sheet linearly to a velocity and maintaining the velocity of said sheet and belt at a uniform value during the time said belt moves from said second position to a third position, said first perforated section being moved out of communication with said suction station whereby said sheet is released from said belt;
(d) moving said belt from said third position to said first position with said belt decelerating to the initial zero velocity; and
(e) repeating the foregoing steps at least one more time during each revolution of said endless belt conveyor.
15. A mechanism for removing one sheet from a stack thereof and transporting the sheet, comprising:
(a) an endless conveyor belt having a perforated section;
(b) means for moving said conveyor belt from a first position to a second position adjacent said stack so that the perforated section contacts said one sheet during the time said belt is moving linearly with zero velocity as indicated in FIG. 6, and the perforated section is in communication with a suction station;
(0) means for continuously applying suction to said perforated section to vacuum couple said sheet to said belt;
(d) means for accelerating said belt and said sheet linearly to a velocity;
(6) means for maintaining the velocity of the sheet and belt at a uniform value during the period of time that said belt moves from said second position to a third position and said perforated section moves away from said suction station whereby said sheet is released from said belt; and
(f) means for moving said belt from said third position to said first position while said belt decelerates to the initial zero velocity.
16. Apparatus for removing one sheet from a stack thereof and transporting the sheet, comprising:
(a) an endless belt conveyor having a plurality of spaced apart perforated sections;
(b) means for moving said belt conveyor from a first position to a second position where a first perforated section contacts one sheet during a period of time when said belt is moving linearly at zero velocity as indicated in FIG. 6 and the first perforated section is in communication with a suction station;
(c) means for continuously applying suction to said first perforated section to vacuum couple said sheet to said belt; a
(d) means for accelerating said belt and said sheet linearly to a velocity'and maintaining/the velocity of said sheet and belt at a uniform value during the time said belt moves from said second position to a third position, said first perforated section being moved out of communication with said suction station whereby said sheet is released from said belt;
(e) means for moving saidbelt from said third position to said first position with said belt decelerating to the initial zero velocity; and
(f) means for repeating the cycle at least one more time during each irevolution of the endless belt conveyor.
7 References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS '6/60 Great Britain.
M. HENSON WOOD, 111., Primary Examiner.
' ERNEST A. FALLER, SAMUEL F.