US3025051A - Sheet handling apparatus and method - Google Patents

Description

March 13, 1962 B. F. DAVID ETAL SHEET HANDLING APPARATUS AND METHOD 2 Sheets-Sheet 1 Filed NOV. 2, 1960 INVENTORS BRUCE F. DAVID RALPH L. DIMENNA BY Q4 60%;

AT ORA/E) March 13, 1962 B. F. DAVID ETAL 3,025,051

SHEET HANDLING APPARATUS AND METHOD Filed Nov. 2, 1960 2 Sheets-Sheet 2 States Patent Ofiiice 3,925,051 Patented Mar. 13, 1952 3,625,051 SHEET HANDELEING APPARATEE AND METHUD Bruce F. David, Vestal, and Ralph L. Dimmenna, Binghamton, N.Y., assignors to International Business Machines Qorporation, New York, N.Y., a corporation of New York Filed Nov. 2, 1960, Ser. No. 66,321 8 (,laims. ill. 271-- i) This invention relates to apparatus and methods for handling sheets, such as bank checks, at high speed, and more particularly relates to an apparatus and method for accelerating sheets of varying random lengths and thickness from one speed to a higher speed in such manner as to maintain a constant predetermined gap between successive sheets irrespective of variations in the lengths and thickness of such sheets.

In reader-sorter equipment for bank checks, checks of varying random lengths and thicknesses are fed successsively past write and read stations, each having sensing means such as electro-magnetic transducers or heads, and are then sorted according to the information recorded on each check. The sensing means at the read station scans each check and after all the code information thereon is read, time is required to calculate a decision and thereafter to translate the decision into action, such as opening a chute blade for a particular pocket to cause the check to be deposited in that pocket. This elapsed time from the inception of reading until the opening of the chute blade is very short and is measured in milliseconds, but nevertheless it constitutes the minimum required operating time which must be allowed in designing the equipment. This minimum operating time is translated into a minimum gap, space or distance which is required between checks on the basis of operation at the maximum transport speed past the write and read stations.

Equipment heretofore proposed comprises a separator to separate and drive each check serially at one speed, an accelerating means which, at or shortly after the instant the check leaves contact with the separator, engages the check and increases its speed and transports it past a sensing station. With this type of arrangement, the gap or space between one check and the succeeding check varies and is proportional to the length of said succeeding check. This follows from the fact that the separator drives a long check at low speed for a longer period of time than a short check, thereby causing a correspondingly greater gap to be developed between such long check and the preceding check which is then being taken away at a faster speed by the accelerating means. Thus such equipment must be designed to provide at least the minimum required operating time under the most critical condition, namely, when two short checks are fed in sequence and the gap between these checks is therefore at a minimum. Hence, when longer checks are fed and the gap increases accordingly, any increase in the gap beyond the minimum is wasteful and unnecessary, and undesirably restricts the potential output of such equipment.

The principal object of this invention is therefore to provide a sheet handling apparatus and method capable of maintaining a substantially constant predetermined gap between successive sheets despite random variations in their lengths and thicknesses, which gap corresponds substantially to, and is at least equal to, the aforementioned minimum required gap, thereby to provide a substantial increase in the output of such as a reader-sorter machine for bank checks without requiring an increase in the transport speed of the machine.

Another object is to provide an improved apparatus of the above type which provides smoother sheet flow and quieter operation than sheet handling apparatus of the types heretofore proposed that embody means to effect progressive increases in sheet feed speed.

According to the invention, the improved sheet handling apparatus comprises picking means for continuously feeding successive sheets, such as bank checks, from the top of a stack in a hopper and into a throat between a separator wheel and a restraint belt. The Wheel has a high coefiicient of friction and speed and engages and advances each sheet in a direction away from the hopper, whereas the restraint belt, which has a lower coefficient of friction and speed, tends to drive the sheet in the opposite direction, thereby to assist in separating the sheets so that only the sheet directly engaged by said Wheel will be fed toward an accelerating or take-away roll and cooperating idler roll. The restraint belt has enough give to provide an automatically adjustable throat between it and the wheel to accommodate sheets of varying random thicknesses. The bite or pinch points of the take-away roll and idler roll is less than the length of the shortest sheet from the pinch points of the separator wheel and restraint belt, and the take-away roll has a peripheral speed greater than that of the separator wheel. An overrunning or slip-type clutch associated with the separator wheel permits it to slip and be driven by the sheet as soon as the sheet enters the take-away roll and is taken away thereby at high speed.

In this improved apparatus, a substantially constant space or gap is provided between successive sheets, which gap is dependent upon the shortest distance between the pinch point of the take-away roll and idler roll and the pinch point of the separator wheel and restraint belt and on the differences in peripheral speeds of said take-away roll and separator Wheel. Thus, if the peripheral velocity of the separator Wheel is half that of the take-away roll, the gap between successive sheets will always be substantiaily equal to the shortest distance between the sheetcontacting portions of the separator wheel and take-away roll, regardless of random variations in the length of the sheets. The term shortest distance is used because in an arrangement such as herein disclosed, the separator wheel impinges on the run of the retraint belt sufiiciently to provide arcuate (rather than linear) frictional contact of the belt and wheel with a sheet, the shortest distance being measured from the extremity of such are which is nearest the take-away roll. This gap is so selected as to provide at least, but not appreciably more than, the minimum operating time required for completion of successive sensing or other operations.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a diagrammatic side elevation view of a sheet handling apparatus embodying the invention;

FIG. 2 is a fragmentary View, to enlarged scale, taken along the line 22 of FIG. 1; and

FIG. 3 is a fragmentary view, to enlarged scale, taken along the line 3-3 of FIG. 1.

Description 14 and over a curved upper end 15 of a vertical side wall 16 of the hopper and into a throat 17. As illustrated, this throat is defined between respective endless driving surfaces of a separator Wheel 18 and a restraint belt 19.

As illustrated in FIGS. 1 and 2, wheel 18 comprises a hub 20, a disc 21 joined to the hub and perforated to reduce weight and inertia, and a belt 22 non-slippably mounted over the widened cylindrical rim of the disc. The belt 22 has uniformly spaced transversely extending recesses 23 in its outer periphery, the non-recessed part of said periphery constituting the driving surface of wheel '18. Belt 22 is formed of material, such as rubber, having a high coefiicient of friction. As illustrated, the belt 22 impinges on a run R of belt 19 to provide arcuate (rather than merely linear) frictional contact with a check 11 when such check is interposed in the throat 17 between said belts.

The driving surface of the separator belt 22 is adapted to be driven clockwise, as viewed in FIG. 1, at a predetermined speed from a shaft 24 through the medium of a wrap-around spring clutch 25 (see FIG. 2). Shaft 24 is suitably journaled in ball bearings carried within a housing 26 carried by a back plate 27. Collars 28, 29 are pinned to shaft 24 at opposite ends of hub 20. The shaft 24 is adapted to be rotated at a constant speed through suitable drive mechanism (not shown), such as a pulley-driven belt disposed behind back plate 27. As illustrated, the clutch 25 comprises a helical spring, preferably having coils of square cross section, that surrounds, and normally grips, both the collar 28 and a hardened sleeve 30. Sleeve 38 encircles the hub 21 and is secured by a pin 31 to disc 21 so that the sleeve 311 and wheel 18 rotate in unison. The purpose of the clutch 25 will be explained presently.

Restraint belt 19 is composed of a material such as rubber-impregnated fabric having a somewhat lower coefficient of friction than belt 22, but higher than the maximum coefiicient of friction between any of the checks. Belt 19 is preferably provided with longitudinally extending serrations. As illustrated in FIG. 1 this belt 19 is driven by a pulley 34 and around idler pulleys 35, 36, 37, 38, 39. Pulley 34 is driven clockwise by a shaft 48 at a uniform speed which is a very small fraction of the speed of the separator wheel belt 22, said shaft being rotated by suitable drive means (not shown). Thus, the high friction separator wheel belt 22 rotates to drive any check in direct contact therewith in a checkadvancing or leftward direction; however, the lower friction restraint belt 19 tends to drive any check in contact therewith in the opposite direction, thereby assisting in separating checks which may accumulate at the throat 17 and assuring that only the check which is in direct contact with the belt 22 will be fed by and past the separator wheel 18. Also, since belt 19 moves, it presents a changing surface for engagement by the rapidly moving separator belt 22 thus distributing wear evenly over the entire surface of the relatively long belt 19.

The run R of belt 19 extends between pulleys 36, 37 which are disposed at opposite sides of throat 17. This run has sufficient give to permit checks of varying thicknesses to pass singly through the throat. The extent of such give is limited, however, by a belt-tensioning spring 41 which acts to maintain the belt 19 taut irrespective of belt stretch or wear during use. As illustrated, spring 41 is anchored to the support for pulley 37 and hooked to one arm of a generally L-shaped lever 42, the other arm of which is pivotally supported on drive shaft 40. At the junction of these arms, the lever 42 carries a pin on which the tensioning pulley 35 is rotatably supported. Thus, spring 41 biases lever 42 clockwise, as viewed in FIG. 1, to pull pulley 35 against belt 19 to take up belt slack.

The checks 11 are fed successively and continuously by and past the separator wheel 18 along a predetermined path defined between upper and lower guides 45, 46 respectively. An accelerating or take-away means 47 is disposed along said path and less than the length of the shortest check from the exit end of the arc of contact of the separator wheel belt 22 with a check 11 (or with run R).

As illustrated, means 47 comprises a take-away roll 48 and an idler roll 49. Roll 48 is driven clockwise by a shaft 50 rotated by suitable drive means (not shown) to impart to roll 48 a predetermined peripheral speed which is higher than that of the separator belt 22. Roll 48 is composed of a material having a high coefficient of friction, such as synthetic rubber. Idler roll 49 is rotatably supported on a stud 51 carried by one arm of a bell crank 52 rockably supported at its knee on a shaft 53. A spring 54 is hooked into the other arm of hell crank 52 and suitably anchored by connection to a bracket 55 secured to back plate 27. Spring 54 biases the bell crank 52 clockwise, as viewed in FIG. 1, to rock the idler roll 49 toward contact with the take-away roll 48 and thus permits the rolls 48, 49 to separate as necessary to permit passage of checks of different thicknesses.

Suitable longitudinal slots are provided in the upper and lower guides to permit the rolls 48, 49 to contact each other and also permit belt 22 and the belt 19 to contact each other when no check is interposed therebetween. As illustrated in FIG. 2, upper guide 45 is formed integrally with the lower part of a two-piece shield assemblage 56 that has uppper and lower bearing-shell-like parts which are clamped together by screws 57 and about a sleeve 58. Lower guide 46 is carried by a bracket 59 (FIG. 1) supported on shaft 53.

Since the exit end of the arc of contact of the belts 22, 19 and the bite or pinch points of the rolls 48, 49 are spaced apart a distance less than the length of the shortest check, and the take-away roll 48 has a higher peripheral speed than that of separator belt 22, the leading part of a check 11 will contact and be driven by the take-away roll while its trailing part is still between the separator wheel belt 22 and restraint belt 19. The separator wheel 18 can thereupon slip and enable the check to be promptly accelerated by the take-away roll 48 because wheel 18 is driven by shaft 24 through the slip-type overrunning spring clutch 25. During clockwise rotation of shaft 24 as viewed in FIG. 1, the spring 25 will wrap up and frictionally drive the separator wheel 18 and hence any check 11 in contact with belt 2 2. However, while a check is concurrently within the bites of rolls 48, 49 and belts 22, 19 and the check is thus being pulled away by the takeaway roll 48 at a higher speed than that imparted by the separator wheel belt 22, belt 22 will be driven clockwise by the check at a speed in excess of the separator belt speed. This driving or slipping of belt 22 and wheel 18 is permitted by the unwrapping of spring 25.

As the check is accelerated and advanced by the takeaway roll 48, it will be guided between guides 45, 46 onto the periphery of a rotating aligning drum 69. This drum 60 has a cylindrical driving surface 61 that is to the rear, as viewed in FIG. 1, of and flush with a wide stationary guide surface 62 formed by a peripheral flange of a stationary crescent-shaped guide 63. Drum 60 is rotated, at a peripheral speed equal to that of the take-away roll 48, by a belt 64 that has arcuate contact with a flange or rim 65 projecting concentrically outwardly from the rearmost part of said drum. Belt 64 is driven from a shaft 66 by a driven pulley 67 and passes around two idler pulleys 68, 69.

As a check is fed onto the aligning drum 60, it passes under a rear guide 45 (FIG. 2) as well as guide 45 and between a caster 70 having a surface with a high coefficient of friction and a driven roll 71 having a drive surface with a low coeflicient of friction. The caster 70 can swivel as necessary to direct the rear edge of the check, as viewed in FIG. 1, into aligning registration with the front side of the aligning rim 65. After it passes caster 70, a check is maintained in contact with the driving surface 61 of aligning drum 60 by a suitably anchored concave guide 72. It then preferably is advanced past a second caster 73 which serves the same function as caster 70 and is provided as a double protection to assure accurate alignment of the check against rim 65. If these two casters are used, caster 70 should be spaced at greater dis tance from rim 65 than caster 73, and the casters should be spaced close enough so that the shortest check will be engaged by caster 73 before leaving caster 70.

After passing caster 73, the check is directed by a guide (not shown) onto a drum 75 having a rim 76 formed of high friction material, and is then driven by a belt 77 onto a reversing drum 78. As illustrated, belt 77 is driven by a pulley 79 from shaft 66 and passes around a groove in the periphery of drum 78. The check is then driven around reversing drum 78 by two pulley-driven belts 80, 81 and then between upper and lower guides 82, 93. Another pulley-driven belt 84 picks up the check as it enters these guides and drives the check past magnetically controlled selectors which select the particular one of a plurality of pockets into which the particular check is to be deposited. Details of the selectors and pockets are not shown and details of the various belt drives are not de scribed in detail because they are not essential to an understanding of the present invention.

For purposes of the present invention, it need merely be noted that after leaving the take-away roll 4-8, the check is advanced at the same speed as that at which it left said take-away roll (namely, the transport speed of the machine), until it is deflected into an appropriate pocket. Also, after passing onto drum 75 the check passes a write head 91 and a read head 91 circumferen' tially spaced adjacent, and slightly offset to the rear of, the outer periphery of drum 75. Write head 90 comprises an electromagnetic transducer that magnetizes the magnetic ink characters previously recorded on the check. Read head 91 comprises a similar transducer that reads these characters and provides a signal to an appropriate one of the aforementioned magnets that control the selectors. Suitable means are provided to urge the checks into contact with these heads 90, 91. As illustrated, these means are in the form of spring-biased convex members 92 that are disposed behind the drum 75, as viewed in FIG. 1.

The aligning drum 60 is rotatably journaled on a bearing (not shown) carried by a shaft or stud 93. Drum 75 is driven from a shaft 94 which also drives a pulley 95 that, in turn, through a belt 96 and a pulley 97 supported on a shaft 98, drives the roll 71. Drum 73 is driven from a shaft 99.

As illustrated, the picker means comprises a hexagonal groove pulley 109 pivotally carried at one end of an arm ltll rockably supported on a shaft 102 that drives a pulley 16-3 to thereby drive a picker belt 104 that runs around said pulleys. Downward rocking movement of the arm 101 about shaft 102 is limited by contact of the under side of the arm with a ledge 105 provided on an arm supporting bracket.

Suitable means is provided for maintaining the top of the stack of checks 11 at a substantially constant height. This means may comprise a switch 106 which is inter posed in a suitable electric circuit for a motor (not shown) that is connected through such as a sprocket drive (not shown) to drive platform 12 up whenever the motor is operated. Switch 106 is biased to a closed position to close the circuit and energize the motor (provided a start switch, not shown is closed). However, when the top of the stack is elevated to a point where arm 101 is rocked clockwise a sufficient extent about shaft 102 to depress the plunger of switch 106, said switch will be opened to open the circuit and thus stop the motor and hence stop further elevation of the platform 12.

6 Summary of Operation Referring to FIG. 1, as checks 11 are continuously fed by picker means 16 from a stack on platform 12, they will be advanced into throat '17. The high friction separator belt 22 will then be rotating at a preselected speed to drive the check which is in contact therewith in a checkadvancing or leftward direction, whereas the lower friction restraint belt 19 will be rotating at a slower speed and tend to drive any check in contact therewith in the opposite direction. The restraint belt 19 will thus assist in separating checks which may accumulate at the throat 17 and assure that only the check in actual contact with the separator belt 22 will be driven past the separator wheel 18. It will be noted that the run R of belt 19 has sufficient give to permit checks of varying thickness to pass singly through the throat 17.

Since the exit end of the arc of contact of a check with separator belt 22 and run R of belt 19 is less than the length of the shortest check from the bite or contact points of take-away roll 48 and roll 49, a check will always enter rolls 48, 49 while the trailing part of the check is still between the separator belt 22 and belt 19. Since the take-away roll 48 has a higher peripheral speed than that of the separator belt 22, the separator wheel 18 and belt are driven impositively through the wrap-around spring clutch 25 to enable the wheel and belt to be driven by a check and slip relative to shaft 24 while a check is concurrently contacted by both roll 43 and belt 22. This enables the take-away roll 48 to promptly accelerate a check from the peripheral speed of belt 22 to the higher peripheral speed of said take-away roll and strip the trailing part of the check from between belts 22, 19 with out damage.

As the check is pulled out from between the belts 22, 19 at the speed determined by roll 48, the separator wheel 18 will be driven by the check and hence .its speed will increase momentarialy until the trailing edge of the check passes the exit end of the aforementioned arc of contact of the belts 22, 19 with the check. During this speed-up, the succeeding check will be advanced through said are such that its leading edge will substantially abut the trailing edge of the check being stripped, until the latters trailing edge passes said exit end, whereupon the separator belt 22 will promptly decelerate and will once again be driven at the normal lower speed through shaft 24 and clutch 25. During this period of deceleration, there will be a slight overcasting of the check then between the belts 22, 19; in other words, said check will be driven momentarily at a speed higher than said normal lower speed until deceleration is completed.

The duration of this deceleration period, and also of the acceleration period, will be determined by the inertia of the separator wheel 18 and the friction between the check surface and belt 22. To minimize this period, the inertia of the separator wheel 13 is made as low as possible by not only using a disc 21 of light material but also perforating the disc. If desired, a electro-rnagnetic brake could be used to effect almost instantaneous reduction in speed of the belt 22 to said normal lower speed as soon as the preceding check passes beyond the arc of contact of the belts 22, 19 with said check.

The purpose of this arrangement will now be explained. As each check is accelerated by and to the speed of the takeaway roll 48, a gap will be created between such check and succeeding check. This gap will be substantially constant irrespective of random variations in the lengths of successive checks because the magnitude of the gap is determined by the relative peripheral speeds of the separator belt 22 and take-away roll 43, and by the shortest distance between the bite of rolls 48, 49 and the bite of belts 22, 19. In the embodiment illustrated, since the belts 22, 19 frictionally contact a check through an arc, and the rolls 48, 49 have linear contact with the check, the shortest distance is the distance between the exit end of said are and the bite or contact points of said rolls. The effects on a check of acceleration of the separator wheel 18 and subsequent deceleration thereof tend to cancel each other out. It has been found in actual tests that if the peripheral speed of the take-away roll 48 is twice that of the separator belt 22, the gap G will be substantially equal to said shortest distance. In reducing the invention to practice, the ratio of the speeds of the roll 48 and belt 22 is set as necessary to offset the net efiect, if any, of the successive acceleration and deceleration of the separator belt 22 in order to give a desired gap G.

It will now be seen that this constant gap results from the fact that each check, irrespective of its length, is driven by the separator belt 22 for exactly the same period of time and over exactly the same distance; namely, from the instant the leading edge of the check enters the bite of belts 22, 19 and until it enters the nip of rolls 48, 49. Of course, the period of time the check will be between (but not necessarily driven by) the belts 22, 19 will vary according to the length of the check. After the said period of time, and for a variable interval of time dependent upon the length of a particular check, said check will be driven by take-away roll 43 at the higher speed of said roll. The next succeeding check will not enter the bite of belts 22, 19 until the trailing edge of said particular check leaves the bite of said belts. As soon as this occurs, belt 22 no longer will be operatively driven from roll 48; hence, clutch 25 will grab and be driven by shaft 24 to cause belt 22 to be driven at the normal slower speed of the separator belt until the leading edge of said next succeeding check is advanced into the nip of rolls 48, 49. The grabbing action of clutch 25, assisted by the low inertia of separator wheel 18 and the frictional drag exerted by the restraint belt 19 on said following check, will tend to reduce the duration of the overcasting or deceleration period above referred to.

Thus, the leading edge of each check, as it starts to enter the bite of belts 22, 19, will initially substantially abut the trailing edge of the preceding check. However, as soon as the trailing edge of the check leaves the bite of belts 22, 19, the gap between said trailing edge and the leading edge of the next succeeding check will progressively increase to a dimension corresponding to the constant preselected gap. This gap will thereafter be maintained constant as the check is advanced past the write and read heads 90, 91 because the various belt drives will continue to drive the check at substantially the same speed as the peripheral speed of the take-away roll 48. Hence, variations in the lengths of the respec I tive checks will affect the number of checks processed per unit of time, or in other words the throughput of the apparatus. Consequently, the throughput will be greatest when all checks are of the minimum length; however, despite random variations in the lengths of the checks, the gaps between successive checks will always be a substantially constant preselected dimension.

Thus, with the arrangement herein disclosed, there is maintained between successive checks a substantially constant gap which is calculated to be very slightly greater than the minimum time required for the electro-magnetically controlled write and read heads 90, 91 to perform their magnetizing and reading operations on one check before being required to perform similar operations on a succeeding check.

Thus, the constant gap is achieved because each check, irrespective of its length, is driven at substantially the surface speed of the separator belt 22 for a constant time necessary to advance its leading edge a fixed distance from the bite of belts 2-2, 19 to the nip of rolls 48, 49; and the next check always enters the bite of separator belts 22, 19 immediately behind the departing preceding check. The only variable resulting from variation in lengths of checks is the length of time the check is driven by the take-away rolls 48, 49 before the next check enters the uppermost check with which it is in contact at a speed equal to or slightly greater than the peripheral speed of separator belt 22. However, even though a very long check may have a long tail extending rearward from the separator means 13 toward the hopper at the instant the leading edge of such check is initially contacted by and starts to be driven at the high speed of the takeaway rolls 43, 4-9, an adequate supply of checks to the separator means is maintained by the picker belt 104. This can best be understood by an example, which is in accord with the apparatus as shown in FIG. 1. Assume that the distance between the check-engaging portion (at MS) of belt 134 and the nip of belts 22, 19 is five inches; and that said nip is two inches downpath from the curved end 15 of the hopper contacted by the respective leading edges of the checks. It is apparent that the picker belt 3334 drives successive checks only a short distance, namely the two inches between end 15 and the nip of belts 22, 19; and that as soon as the trailing edge of any check passes leftward of pulley 1th the belt 194 will immediately and without interruption commence feeding the next check leftward In other words, even though a long check is driven at the high speed of the take-away rolls for a portion of the time before its trailing edge leaves the separator means 13, the picker belt will maintain uninterrupted the supply of checks to the separator means by starting to advance a second check the short two-inch distance as soon as the upper checks trailing edge is live inches away from the separator means.

In actual use of the invention in a reader-sorter machine, it has been found that, without increasing the maximum check transport speed, over twenty-five percent more bank checks of random varying lengths can be processed per minute, than if the same machine is not equipped with the invention. it is desirable to limit the maximum transport speed of the machine because as such speed increases, the possibility of jams and other malfunctions is multiplied.

While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

l. in a sheet handling apparatus, means for providing a substantially constant gap between successive sheets of varying random lengths and thicknesses, said means comprising separator means for singly feeding successive sheets substantially at one speed and in such manner that as the trailing edge of one sheet leaves the separator means the leading edge of the succeeding sheet will effectively enter the separator means and initially substantially abut said trailing edge, take-away means for engaging a sheet advanced thereto at said one speed by said separator means and accelerating it to a higher speed, the distance between the sheet-engaging portions of said take-away means and separator means being less than the minimum length of any such sheet to cause each successive sheet to be driven by the take-away means while still in contact with the separator means, and slip-type drive means for the separator means to permit it to slip and be driven by a sheet after the latter is engaged by said takeaway means and until the instant such sheet leaves the separator means such that after such instant, and while such sheet is being driven by the take-away means at said higher speed and the succeeding sheet is being driven substantially at said.

one speed by said separator means, a gap will be created between such sheet and the succeeding sheet which gap is substantially constant irrespective of variations in sheet lengths and is a function of the distance between said portions and the relative and separator means.

2. The combination according to claim 1, wherein the separator means comprises a separator and a restraining means each providing endless sheet-driving surfaces, the surface of said restraining means having a coefiicient of friction less than that of the separator and acting on the sheet to lightly oppose the driving action of the surface of the separator thereby to assist in separating the sheets and cause only the sheet engaged by the separator to be advanced thereby and therepast.

3. The combination according to claim 2, wherein said separator is in the form of a wheel, and said restraining means comprises a belt that provides a run of suflicient give to permit the space between said run and the separator wheel to resiliently vary as necessary to pass sheets of varying thickness.

4. In a sheet handling apparatus, means providing a constant gap between sheets of varying random lengths and thicknesses, said means comprising means for feeding successive sheets continuously, a separator means and a restraining means each providing respective endless sheetdriving surfaces at least one of which is biased resiliently toward the other for defining a throat of expandable width between which sheets of varying thickness are fed successively by the feeding means, the surface of said separator means moving in a sheet-advancing direction and having a higher coefiicient of friction than the surface of the restraining means which moves in the opposite direction to aid in separating the sheets and assure that they are fed one at a time by and through said separator means with the leading edge of a succeeding sheet initially abutting the trailing edge of the preceding sheet as the latter leaves the throat, take-away means having an endless surface moving at a higher speed than that of said separator means and spaced close enough to said separator means to cause the separator means to move a sheet into contact with the take-away means while such sheet is still within said throat, overrunning clutch means normally engaged to drive the separator means and disengaged by and upon one of the sheets being concurrently engaged by the take-away means and separator means to cause the latter to slip so long as said one sheet is within the throat thereby to create a gap between the trailing edge of such one sheet and leading edge of the succeeding sheet after said one sheet leaves the throat and while said one sheet and succeeding sheet are moving at different speeds, which gap is substantially constant irrespective of variations in the lengths of the sheets and is proportional to the distance between, and relative speeds of, the sheet-engaging portions of the respective surfaces of the separator means and take-away means.

5. The combination according to claim 4, wherein the speed of the surface of said take-away means is twice that of the surface of said separator means to provide a constant gap which is substantially equal to the distance between said portions.

6. Apparatus for handling sheets of varying random lengths, said apparatus comprising, in combination, sensing means for sensing information on the sheets, separator means for feeding successive sheets in initially substanspeeds of the take-away means tially abutting end-to-end relation into a predetermined path leading from the separator means past said sensing means, drive means for normally driving an endless driving surface of the separator means at one constant speed to cause the separator means to move each sheet into said path substantially at such speed, take-away means disposed along said path between said separator means and sensing means and providing at least one endless driving surface positioned to contact the leading part of each sheet before its trailing part leaves the separator means, and other means to drive the surface of said takeaway means at a constant speed higher than said one speed to cause the take-away means to accelerate each sheet to such higher speed, said drive means including a slip-type clutch interposed between the separator means and a drive mechanism, said clutch permitting the separator means to slip and be frictionally driven by each sheet independently of the drive mechanism when and while such sheet is concurrently contacted by said surfaces of the separator means and take-away means thereby to create a gap between the trailing end of such sheet and leading end of the succeeding sheet after such sheet leaves said separator means and is advancing at said higher speed and while said succeeding sheet is advancing substantially at said one speed, said higher speed being so related to said one speed as to cause said gap to be of a desired length which corresponds to at least that time interval necessary for the sensing means to complete a sensing operation, said gap being substantially constant irrespective of random variations in the lengths of the sheets and being substantially proportional to the distance between, and relative speeds of, the sheet-engaging parts of the surfaces of said take-away means and separator means because each sheet irrespective of length is always driven at the speed of said separator means for a fixed predetermined distance and time.

7. The combination according to claim 6, wherein the separator means comprises a separator wheel having a circular belt and also comprises a restraint belt having a run which cooperates with the driving portion of said circular belt to provide an expandable throat space into which sheets are fed, said run having sufiicient give to cause the width of said throat space to vary automatically to accommodate sheets of differing thicknesses.

8. The combination according to claim 7, wherein the run of said restraint belt has a coefiicient of friction less than that of the circular belt and moves in a direction tending to oppose the sheet-advancing direction of movement of the circular belt to assist in separating any sheets which may tend to accumulate in shingle-like fashion at the entry side of said separator means to assure that only the sheet in contact with the separator means will be fed through the throat space.

References Cited in the file of this patent UNITED STATES PATENTS 650,410 Morin May 29, 1900 2,113,078 Campbell Apr. 5, 1938 2,701,049 Kendall et al. Feb. 1, 1955 2,970,537 Wardwell et a1. Feb. 7, 1961

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