US3403903A

US3403903A - Torsion bar sheet separator

Info

Publication number: US3403903A
Application number: US631272A
Authority: US
Inventors: Jesse W Caril
Original assignee: Jesse W. Crail
Current assignee: JESSE W CRAIL
Priority date: 1967-04-17
Filing date: 1967-04-17
Publication date: 1968-10-01
Anticipated expiration: 1985-10-01

Description

0a. 1, 1968 J. w. cm. 3,403,903

TORSION BAR SHEET SEPARATOR Filed April 1'7, 1967 United States Patent "ice 3,403,903 TORSION BAR SHEET SEPARATOR Jesse W. Crail, 3802 Edenhurst Ave., Los Angeles, Calif. 90039 Filed Apr. 17, 1967, Ser. No. 631,272 4 Claims. (Cl. 271-20) I ABSTRACT OF THE DISCLOSURE A vacuum lifter removes the top sheet from a stack which has a vertical stop plate at the forward side of the stack adjacent the upper leading edge. Separator finger means are mounted on a tubular shaft which has associated therewith torsion bar structure for exerting a force on the separator fingers while the lifter means is removing a top sheet.

The present invention relates generally to mechanical finger devices for separating sheets of paper as they are fed by vacuum lifter means into a multilith machine or the like. More particularly, the invention relates to a sheet separator for use in a vacuum lifter paper feed system, in which one or several rigid separator fingers are resiliently moveable on enclosed torsion bar spring systems.

This invention was specially invented to meet a need in multilith machines which use a pair of reciprocating vacuum lifters for feeding one sheet of paper at a time from the top of a paper stack into the printing rolls. However, the invention will find utility in any paper-using machine of a similar type, that is, one in which paper must be fed into the machine, one sheet at a time, by means of some type of vacuum lifter system. Vacuum lifter feeds generally comprise a pair of overhead suction nozzles, which are mounted on a reciprocating paper feed mechanism, and are connected by hoses to a suitable air evacuation pump. In almost all cases, the vacuum lifters are assisted by air lift means which supply a jet of air under the sheet of paper which is being lifted by the vacuum lifter. Usually, a pair of such jets are located on each side of the paper stack from which sheets are being fed, and are arranged to introduce a jet of air under the topmost sheet or sheets which rise in response to the action of the vacuum lifters.

A rising paper stack platform is almost universally used in association with vacuum lifter paper feed systems. The stack of paper supply is supported on a horizontal platform which rises a fraction of an inch each time a pre-determined number of paper sheets have been fed from the paper stack on the platform.

The paper feed operation takes place at a location which may be designated as the upper leading edge of the paper stack. The term leading end of the paper stack refers to the end of the stack disposed in the direction in which the paper is fed from the stack into the machine. The term upper leading edge refers to the general location of the upper edge of the leading end of the paper stack. The paper stack is replenished from the opposite or rear end. The previously mentioned air lift jets are applied to each side of the paper stack, just below its upper surface,and just back of the upper leading edge of the stack.

In the typical vacuum paper feed system, the moveable vacuum lifters descend and make vacuum seizure of the surface of the top sheet of paper an inch or two back of the upper leading edge; the top sheet is then lifted and carried forward in the paper feed direction to the printing rolls.

It is very common for two or three or even more sheets of paper to stick together at the forward leading edge, so

3,403,903 Patented Oct. 1, 1968 that lifting the top sheet actually lifts several sheets. The air jets at each side of the forward leading edge are helpful in separating these sheets and forcing downward all but the top sheet. However, it has generally been found necessary in all the combination vacuum lifter and air lift paper feeds to provide paper separator fingers of resilient spring material at the upper leading edge of the paper stack. Usually, these separators are strips of spring bronze, mounted in a small bracket, which is laterally adjustable at the leading face of the paper stack. The mounting brackets usually function also as leading end paper stops for seating the paper stack at its leading end.

Unfortunately, the leaf-spring separators usually used in association with the vacuum lifter paper feed system have proven unreliable, unless constantly cared for by expert press operators. Consequently, most modern multilith machines employing this type of paper feed combination are presently provided with some auxiliary device which may be called a multiple sheet detector. Usually, a pair of rolls on the paper sheet entering the printing section of the machine is supposed to detect the presence of more than one paper sheet thickness, and automatically actuate a bypass of any such multiple sheet group which is improperly entering the machine. These multiple sheet detectors naturally add to the cost of the machine, and themselves present an operating and maintenance problem. They do not function properly unless watched and serviced by an expert operator.

With the presently known leaf-spring fingers, no two of them ever operate exactly alike, and the same spring finger changes its characteristics each time it becomes slightly deformed in use, an occurrence which is fairly common. Even when the leaf-spring finger is operating at its best, its effectiveness as a paper separator is very much reduced if it deflects upwardly more than a few degrees. Such deflection resiliently deforms the leafspring, causing it to appear to shorten, and to turn its separating end upward rather than backward over and against the forward leading edges of the paper sheets which it should be separating.

It is a major object of the present invention to provide an entirely new kind of sheet separator, and one which is so effective that no skill or attention is required from an unskilled operator. It is the purpose of the present invention, which has been achieved in actual application of the device to multilith machines, to achieve such effective separation by means of the sheet separator that no multiple sheet detector will be needed in the machine.

It is an important associated object of the invention to provide separators in which the separator finger is a rigid structure, which rotates as a unit during separation, without any deformation, and which is unchanging in structure and characteristics throughout its operating life.

Another important object is to provide a sheet separator in which the spring characteristic is substantially constant for the entire operating life of the separator, and the spring is entirely enclosed so that it cannot be damaged, or be deformed by rough and unskilled usage.

The foregoing and other objects of the invention are accomplished by using an entirely enclosed torsion bar system for the resilient support of rotatable but rigid separator fingers.

The foregoing and other objects and advantages of the invention may be understood from the following descrip- O tudinal vertical plane through the paper stack as indicated by the arrow 2 in FIG. 1;

FIG. 3 is a perspective view of an assembly comprising a paper stop for the leading end of the paper stack, and a torsion bar separator constructed according to the invention;

FIG. 4 is an exploded perspective view of the assembly of FIG. 3, but viewed from the opposite side (the downstream side in terms of direction of paper movement);

FIG. 5 is an enlarged perspective view of the torsion bar separator, viewed from the downstream side, with the bearings shown in cross-section in order to reveal the inner construction of the torsion bar spring system.

In FIG. 1, a paper stack 19 is seen (fragmentarially) supported on a rising platform 11, which rises slowly during operation of the machine, by means well known to those familiar with multilith and similar machines.

Overhead, a typical vacuum lifter system, indicated generally by the numeral 12, reciprocates back and forth along a typical path suggested by the double-ended arrow 13. The mechanically operated reciprocating system is indicated only fragmentarially by the bar 14, since it is typical of such machines, and has no novel feature claimed as part of the present invention.

The bar 14 carries a typical pair of vacuum nozzles 15 and 16, from which air is evacuated by a typical hose system indicated generally by the numeral 17, and held on laterally adjustable brackets 18 and 19, respectively.

The typical air lift jets used in association with vacuum nozzles 15 and 16 are designated by the

numerals

21 and 22. Air under low pressure inside of the

nozzles

21 and 22 is jetted from the small openings indicated at 23, and cause the upper leading edges of the paper in paper stack 10 to be in a state of continuous vibration, which tends to produce the desired separating operation. Nearby are side stops 24 and 25 which assist the operator in properly locating the paper stack 10 for feed along the desired center line into a multilith machine not illustrated.

The forward leading edge of the paper stack 10 is indicated by the numeral 30. The paper stack 10 has its leading end seated against a pair of leading end paper stops 31 and 32, which are laterally adjustable on a horizontal, transverse support bar 33.

The vertical sectional view of FIG. 2 illustrates the operation of the paper feed system, which includes the torsion bar separator distinguishing the separator of the present invention from that of the prior art. The paper stack 10 is shown with its leading end 10a seated against the vertical face of the paper stop 32.

In FIG. 1, the torsion bar separators of the invention are designated by the numerals 41 and 42, respectively; and in FIG. 2, a side view of the separator 42 shows that it is constructed of a stationary bracket 43, and a separator finger 44, having internal torsion bar construction to be described hereinafter. The entire assembly 42 is integrally assembled into the paper stop 32 by bolt 45.

In FIG. 2, the separator finger 44- is shown in rest position, but its upwardly deflected position is indicated in dash-line at 46.

Although the paper stack 10 is raised a fraction of an inch at frequent intervals by automatic operation of the rising paper platform 11, the upper surface 10b of the paper stack 10 is normally a fraction of an inch below the elevation of separator finger 44. The combined action of the vacuum lifter 16 and air introduced underneath the top sheet 46, by both atmospheric air pressure and air jetted from the

air lifters

21 and 22, causes the forward leading edge of sheet 46, and perhaps two or three other sheets immediately beneath it, to rise against the underside of the separator finger 44 as illustrated in FIG. 2.

However, as the lifter 16 moves away from a paper stack 10 in the paper feed direction, the top sheet 47 is lifted to the position indicated in dash-dot line by the numeral 48, and its forward leading edge deflects the finger 44 upward to the position 46. As this occurs, the resilient downward pressure of finger 44 sweeps over the edges of any surplus sheets, and with the assistance of air from the

air lifters

21 and 22, the undesired sheets are forced downward.

It is important to note at this point that the action of spring finger 44 is completely unlike that which has occurred with sheet separators of the prior art. The finger 44 of the present invention is a rigid plate of substantial construction, and is not deformed in the slightest. Even when deflected upwardly to position 46, it presents a rigid scraping action to the edges of paper sheets. The brass spring fingers used on present paper separators are re siliently deformed by the paper action, and lose their efiicacy as paper separating fingers, during the momentary upward movement of top sheet 47 to position 48.

FIG. 2 also shows how the paper stop 42 may be slid into any desired transverse position on support bar 33, and clamped into that position by tightening the clamping screw 50.

FIGURFA 3 and 4 are perspective views of the leading end of paper stop 32 and assembly and disassembly, respectively. It will be understood that the paper stop 31 is identical in construction. Ordinarily the paper stops 31 and 32 are use-d in pairs, but in rare instances, narrow sheets might be fed utilizing only one stop, or very wide sheets might require more than two such stops with their associated separators 41 and 42.

It is seen that the paper stop 32 is comprised primarily of a paper stop plate structure 32a, to which the other parts are assembled as previously described. The bracket 43, which carries separator finger 44 is seen to have a pair of

tubular structures

51 and 52 in the upper portion. These are bearings seen in vertical, longitudinal cross-section in the enlarged perspective view of FIG. 5.

Bearings

51 and 52 are axially spaced from one another to accommodate separator finger 44 between them.

FIG. 5 reveals that a tubular shaft 53 is rotatably mounted in

bearings

51 and 52, and entirely enclosed by them, except for a central portion 53a, and a projectingin portion 53b. The rigid spring finger plate is integrally attached to the torsion 53a, for example, by soldering.

A resilient torsion bar is co-axially disposed with

bearings

51 and 52 and tubular shaft 53, and entirely enclosed within their interiors. At the left end, as viewed in FIG. 5, the torsion bar 60 is anchored by a stationary anchoring means 61 to the outboard end of the bearing 51. At its right end, the torsion bar 60 rotates with the projecting end 53b of the tubular shaft 53, and is anchored to the interior thereof by a rotating anchoring means 62, illustrated is dashed outline. It will be understood that anchoring means 61 and 62 are merely illustrative, but some type of anchoring means are employed, but any suitable anchoring means may be used. For example, the tubes may be crimped and a drop of solder added to achieve anchoring.

It will be seen from the foregoing that the sheet separator of the invention provides a resilient sheet separating action utterly unlike that of the previously known leaf spring separators. Whereas the prior art separators were each unlike in characteristics, and often experienced a change in characteristics as a result of deformation during use, the sheet separator of the invention can be constructed to precisely meet a desired spring characteristic, by proper selection of torsion bar 60, and will retain its initial characteristic without variation throughout its entire useful life.

It will be seen from the preferred embodiment illustrated that both the anchoring means 61 and 62 are preferably in an exposed position in which they can be inspected, repaired, or modified.

Also, it is a preferred modification of the invention to employ a spring characteristic for torsion bar 60 which falls within the range of stiffness determined by the properties of the paper in paper stack 10, and the operating characteristics of the vacuum lifter 16- and its associated

air lifters

21 and 22.

While the embodiment illustrated is one of the best and most preferred forms of the invention, it is the intension of the inventor to include all modifications and variations which fall within the scope of the following claims.

What is claimed is:

1. In a vacuum paper feed system which includes means for presenting a paper stack for feed into a machine from an upper leading edge of said stack, and a vacuum lifter means for lifting and passing into said machine one sheet of paper at a time, a sheet separator which includes:

a substantially vertical paper stop plate for seating against the forward side of said paper stack below said upper leading edge;

a pair of co-axial tubular bearing members mounted on said paper stop with their axis parallel to and adjacent to the upper leading edge of said paper stack, said bearing members being axially spaced from each other;

a tubular shaft rotatably mounted in said members and having a central portion exposed in the axial space between said bearing members;

a separator finger integral with said tubular shaft and projecting over the leading edge of said paper stack, and adapted to engage the leading edge of a sheet of paper raised from said stack by said vacuum lifter means; i

a torsion bar co-axially disposed within said tubular shaft;

a rotating anchoring means for anchoring a first end 6 of said torsion bar to one end of said tubular shaft; and

stationary anchoring means for anchoring a second end of said torsion bar to the stationary structure comprising said paper stop and co-axial bearing members.

2. A'sheet separator as described in claim 1 in which the end of said tubular shaft at which said rotating anchoring means is located projects outward of the open end of one of said tubular bearing means.

3. A sheet separator system as described in claim 1 in which two sheet separator combinations are supported at the leading face of said paper stack, and are adjustably locatable along said upper leading edge of said stack independently of each other to provide independent sheet separator control at spaced intervals along said upper leading edge.

4. A sheet separator as described in claim 1 in which air lift means assists said vacuum lifter by introducing a stream of air under the leading edge of paper lifted by said vacuum lifter and in which the spring characteristic of said torsion bar is strong enough to resist deflection by a sheet of paper lifted by said air lift means, but yielding enough to be outwardly deflected by the leading edge of a sheet of paper lifted by a combination of said air lift and said vacuum lifter.

References Cited UNITED STATES PATENTS 1/1946 Curtis 27126 X EDWARD A. SROKA, Primary Examiner.