US2894147A

US2894147A - Load leveller

Info

Publication number: US2894147A
Application number: US624291A
Authority: US
Inventors: Stidwill George Benson Munroe
Original assignee: SMITH PAPER MILLS Ltd HOWARD
Current assignee: HOWARD SMITH PAPER MILLS Ltd; SMITH PAPER MILLS Ltd HOWARD
Priority date: 1956-11-26
Filing date: 1956-11-26
Publication date: 1959-07-07
Anticipated expiration: 1976-07-07

Description

July 7, 1959 Filed Nov. 26, 1956 G. B. M. STIDWILL LOAD LEVELLER 5 Sheets-Sheet 1 6. B. M Swan a;

y 7, 1959 G. B. M. STlDWlLL 2,894,147

LOAD LEVELLER Filed Nov. 26, 1956 5 sheets sheelt 2 July 7 1959 I G. B. M. STlDWILL 7 2,894,147

LOAD LEVELLER Filed Nov. 2a, 1956 s Sheets-Sheet s T0 DISCONNECT SWITCH Y H T0 mscounscr. F C: 5mm

/ :E l- 9 A AAA ?|| souzuom 27 6.5.114 Snow/LL United States Patent LOAD IJEVELLER George Benson Munroe Stidwill, Cornwall, Ontario, Canada, assignor to Howard Smith Paper Mills Limited, Montreal, Quebec, Canada Application November 26, 1956, Serial No. 624,291

Claims. (Cl. 250234) This invention relates to load levelling of sheet material and more particularly to the levelling of loads of cut paper on a layboy at the delivery end of a paper cutter, printing press or similar mechanism.

- The invention consists essentially in projecting a beam of light onto the edge of the piling sheets on the layboy and picking up the reflection from the edge of the sheets by suitable means which is set to effect, through suitable mechanism, the lowering of the layboy when the intensity of the light reflection from the edge of the sheets reaches a specified degree and to effect stoppage of the lowering of the layboy when the intensity of the light reflection is reduced to a specified degree. The maximum high level of the sheets on the layboy at which lowering of the layboy commences can be set with relation to the location of a marker projecting device which, in turn, if used, is set to project a marker onto the top sheet of the load at a specified number of cutting strokes of the cutter, printing press or the like. The load levelling of the layboy, as hereinafter set forth, is entirely independent of the operation of the paper cutter and of the marker projecting device to the extent that it is independent of the number of cutting strokes or the timing of the marker projecting device.

The custom generally in the past has been to manually operate a motor, ratchet or gear which lowers the load as fresh sheets are added in the layboy. Various automatic devices have also been used to perform this function, although none of them have been really satisfactory. Some of these automatic devices mark the paper: others lower the paper at a constant rate despite the likelihood that the paper may be piling at a changing rate or that the paper may not be lying flat due to air pockets etc.

The object of the invention is to provide a load leveller for sheet material on which the load will be lowered a fractional amount each and every time that the top of the load reaches a specified level independent of the number and rate of delivery of the sheets to the load.

A further object of the invention is to provide a load leveller for sheet material on which the intensity of light reflection on the edge of the sheet material determines the maximum height of the load and sets in motion the lowering of the load from the maximum height.

A further object of the invention is to provide a load leveller for sheet material in which the intensity of light reflection from a light source is picked up by a photoelectric tube or photoconduction cell which in turn controls the lowering of the load in accordance with the degree of light reflection intensity.

A further object of the invention is the elimination of any mechanical mechanism for counting the sheets on the load or physical measuring of the level of the load to control the lowering of the load of sheet material.

A further object of the invention is to provide a load leveller for sheet material which can be readily adjusted to suit various working conditions and which can be changed from automatic to manual control when required.

A further object of the invention is to provide a light 2 responsive load leveller which can be adjusted to suit the light responsiveness of the material caused by difierent colours of material to be loaded.

These and other objects will be apparent from the following specification and the accompanying drawings in which:

Fig. l is a fragmentary side view of a layboy located at the delivery end of a paper cutter and showing the location of the photo electric tube with all other extraneous mechanism eliminated.

Fig. 2 is a fragmentary cross sectional view taken'on the line 22 of Fig. 1 showing the light source element, the photo electric tube and the marker dispenser.

Fig. 3 is a diagram showing the paper load at its lowest set level with relation to the light source and photo electric tube and showing a minimum of light reflection on the edge of the piled paper.

Fig. 4 is a diagram similar to Fig. 3 showing the level of the paper raised with increased area of light reflection.

Fig. 5 is a diagram similar to Figs. 3 and 4 showing the level of the paper raised to its maximum level with an area of light reflection which will react on the photo electric cell to cause activation of the lowering mechanism.

Fig. 6 is a diagram similar to Fig. 3 at the completion of the lowering cycle where the light reflection is reduced to the point where photo electric cell will cut off activation of the lowering mechanism.

Fig. 7 is a schematic wiring diagram of the circuit to the layboy lowering mechanism in which. a light source and a photo electric tube are employed to activate the layboy lowering mechanism.

Fig. 8 is a schematic wiring diagram of the circuit to the layboy lowering mechanism in which a photo inductive cell takes the place of the photo electric cell shownin Fig. 7.

Referring to the drawings, the layboy 5 may be of any of the well known makes and is located at the delivery end 6 of the paper cutter '7. As both the paper cutter 7 and the layboy 5 can be of any well known form only their features essential to the operation of the present invention are shown. The paper cutter 7 has a delivery roll 8 over which the delivery tapes 9 are trained. The layboy 5 is provided with the paper guide bars 10 spaced at suitable intervals across the machine and has a load carrying platform 11 supported by suitable ropes or chains 12 on the pulleys 13 which can be driven by electric motors or other means through suitable speed reducing mechanism, not shown.

Jogging lingers 14 are mounted at intervals across the machine on the rocking shaft 15, and support and move the sheets of paper 16 from the delivery tapes 9 forward onto the top of the load 17 being built up on the platform 11.

A marker dispenser device 18 may or may not be fitted on the machine and one type is here shown as being supported from and controlled by the cutter 7 to dispense markers 19 on to the top of the load of out paper 17 at a speciied number of operations of the paper cutter knives.

The above described mechanism is generally common to all machines feeding cut sheets to a loading platform. The sheets may come from a machine cutting sheets from a roll or a multiple of rolls or the sheets may come from a printing press or similar types of machines.

The invention hereinafter described in detail comprises the installation of a light source 2% and a. photo electric tube 21 suitably protected in casings Ztla and 21a. These

casings

20a and 21a are mounted on a plate 22 secured to one of the paper guide bars ltia which may be cut down in height so as not to interfere with the projected light source 20 and the photo electric cell 21 in any of their adjusted positions. The plate 22 is slotted at 23, to allow for vertical adjustment and is held to the bar 10a by isslotted at 20b to project a beam of light of limited area against the edge of the load of paper and the height of the slot 20b is coordinated with the slot 21b in the casing 21 so that the photoelectric tube therein'will pick up the light reflected from the edge of the paper sheets over a fixed range of light intensity. The 5,SlOtS 20b and 2112 are set at an angle on ahorizontal plane so thattheir axes will be focalized on the vertical plane represented by the edge of the sheets in the load 17.

The area of reflected 'light35 at the edge of the paper load 17 increases in intensity as the load is built up by thesheets 16;being fed from the delivery tapes 9 as shown in Figs. 3, 4, and 6. A working cycle of :load levelling would be as follows, referring to Figs. 3, 4, 5 and 6. In Fig. 3 the area of reflected light 35 from the light source 20 is small and its intensity will not be sufiicient to effect activation .of the photoelectric tube 21. In Fig. 4 the sheets 16 have built up the load 17 to increase the area of light reflector 35 but still not sufficient to activate the photoelectric tube 21. In Fig. 5 the area of reflected light 3.51has reached a degree of intensity to activate the photoelectric tube thereby effecting start up of the drive to the pulleys 13 and the lowering of the platform 11 with its load 17, shown in Fig. 1. Lowering of the load will continue until the intensity of light reflection 35 is reduced to the small area shown in Fig. 6. During the cycle of operation the sheets 16 continue uninterruptedly to pile onto the load 17 and the .cycle of lowering operation is continued until the maximum height of load 17 desired has been reached at which time the selector switch 26 is moved to the off position and the load removed from the machine and a new loading operation started.

The maximum high level of the load 17 shown in Fig. 5 is set with relation to the projection level of the markers 19 ejected from the dispenser 18, in order that, under all operating conditions the marker 19 can be projected forwardly over the top of the load and under the sheet 16 immediately above as it is jogged forwardly of the jogging arms 14. The projection of the marker 19 is coordinated with a predetermined number of cut sheets being discharged by the paper cutter 7 or, in the case of a printing or other like machine, with a predetermined number of sheets passing through the machine to the layboy, and is not related to the number of sheets built up on the load 17 below the maximum set level.

Any tendency for individual sheets 16 or layers of sheets to bulge upwards due to air pockets or other causes will immediately tend to increase the area of light reflection at the top edge of the load and will set in motion when the predetermined light intensity has been reached, the lowering of the load, regardless of the number of sheets in the area of the light reflection. By this means, under normal and abnormal conditions of loading of the sheets, the level cannot rise above the set maximum, and free space is always available between the top of the load and the oncoming sheet into which the marker 19 can be projected.

In Fig. 7, a typical schematic wiring diagram is shown in which a photo-electric tube 21 picks up the reflected light projected onto the load 17 at 35 from the light source 20. The magnetic relay 28 is closed when the tube 29 is made conductive when light is applied to the photo-electric tube 20. The load magnetic relay 30 is opened when the tube 31 is made conductive. This latter tube 31 is operated by a time delay circuit regulated by the variable resistor 32 which, in turn, is energized by the relay 28. The selector switch 26 has three positions, the off position *O; the hand operating position H, and the automatic operating position A. Control of the mechanism for rotating the pulleys 13 and the lowering of the load 17 is effected by the operation of the solenoid 27 when the circuit is energized through activation of the photo-electric tube'21.

In Fig. 8 a modification of the schematic wiring diagram shown in Fig. 7 is shown. In this diagram a photo-conductive cell 33 replaces the photo-electric tube ,21 and the tube 29. The use of a photo-conductive cell 33 is of particular advantage when the space available between the delivery roll 8 of the paper cutter 7, or other similar machine, and the layboy 5 is limited.

While two possible circuits are shown, these could be varied considerably while still performing the function of controlling the level of the load. For instance, the magnetic relays 28 and Y30 could just as easily be replaced by electronic tubes in the circuit.

In the operation of loading cut paper sheets onto the platform 11, the platform is first raised to a convenient height to take the first few sheets 16 until the light from the light source illuminates an area of increasing intensity and finally reaches a degree sufficient to activate the photoelectric tube 21 or the photo-conductive cell 33 as shown in Fig. 8. The sensitivity of the photo-electric tube 21, or'the amount of illumination provided by light .20, in either case can be adjusted to suit the varying degree :of

light reflectance provided by the paper beingpiled :on the layboy. Such adjustment is required when changing over from white to a coloured paper or from light to dark coloured papers. The period of time during which the photo-electric tube or photo-conductive cell remains activated, is set to lower the platform 11 a short distance during each operating cycle of the device. Such lowering distance will depend on the amount of time delay provided by the vacuum tube 31 which in turn is controlled by the variable resistance 32. To some extent the lowering operation will also depend upon the thickness of individual sheet being loaded but for paper of average thickness the lowering distance would be approximately inch.

Satisfactory operation of the device is obtained despite the fact that there may be anywhere from one to twenty or thirty sheets falling through the air to the solid part of the load and going by the light source and light sensitive device, the air gradually squeezes out of the space between the sheets of .paper as they land on the top of the load and the sheets gradually pack into a tighter and tighter pile. In the meantime, the light from the light source is being reflected back from the edge of the individual sheets of paper. It is theaccumulation of these multitudinous edge reflections which operates the light sensitive device and not a sharp edge of a solid material. The time delay has the effect of accumulating and integrating the many reflections from the edges of the paper so that when enough paper has piled on the load the light sensitive device will activate the load lowering apparatus.

By combining a light source of given intensity and a photo-electric tube or photo-conductive cell of known sensitivity and knowing the reflective value of the surface of the sheets being loaded, the lowering of the load can be controlled to within fine limits and the travel from the maximum high position to a minimum low position adjusted to suit all operating conditions. In addition, false counts of the sheets are eliminated as the sheets are never allowed to rise to a height which would block the forwards projection of a marker 19 as is often the case where counting of the sheets on the platform is relied upon or where the platform is lowered a fixed distance at set intervals, regardless of any change of rate of delivery of the sheets.

What I claim is:

1. In a device for continuously loading and counting sheets of paper or the like, means for maintaining the top of the constantly increasing load of sheets at or below a maximum predetermined level, a platform supporting the constantly increasing load, said platform being carried by platform raising and lowering mechanism, fixed level feeding means directing the sheets onto said platform, a source of light directed onto the edge of the sheets being loaded and onto the vertical face of the rising load at a predetermined level below the said feeding means, a light sensitive device activated by the increasing degree of light sensitivity on the edges of the sheets on the face of the rising load, the said source of light and said light sensitive device being mounted on a common support bracket on said platform, the activation of said light sensitive device setting in motion the lowering of said raising and lowering mechanism to lower said platform and its load to a point where the light intensity on the face of the load is decreased and the light sensitive device ceases to be activated, and means to adjust the level of said source of light and said light sensitive device relative to said feeding means.

2. In a device for continuously loading and counting sheets of paper or the like, means for maintaining the top of the constantly increasing load of sheets at or below a maximum predetermined level, a platform supporting the constantly increasing load, said platform being carried by platform raising and lowering mechanism, fixed level feeding means directing the sheets onto said platform, a source of light directed onto the edge of the sheets being loaded and onto the vertical face of the rising load at a predetermined level below the said feeding means, a light sensitive device activated by the increasing degree of light sensitivity on the edges of the sheets on the face of the rising load, the said source of light and said light sensitive device being mounted on a common support bracket on said platform and focalized on a common point on the face of the rising load, the activation of said light sensitive device setting in motion the lowering of said raising and lowering mechanism to lower said platform and its load to a point where the light intensity on the face of the load is decreased and the light sensitive device ceases to be activated, and means to adjust the level of said source of light and said light sensitive device relative to said feeding means.

3. In a device for continuously loading and counting sheets of paper or the like, means for maintaining the top of the constantly increasing load of sheets at or below a maximum predetermined level, a platform supporting the constantly increasing load, said platform being carried by platform raising and lowering mechanism, fixed level feeding means directing the sheets onto said platform, a source of light directed onto the edge of the sheets being loaded and onto the vertical face of the rising load at a predetermined level below the said feeding means, a light sensitive device comprising a photoelectric tube, said photoelectric tube being activated by the increasing degree of light sensitivity on the edges of the sheets on the face of the rising load, the said source of light and photoelectric tube being mounted on a common support bracket on said platform, the activation of said photoelectric tube setting in motion the lowering of said raising and lowering mechanism to lower said platform and its load to a point where the light intensity on the face of the load is decreased and the photoelectric tube ceases to be activated and means to adjust the level of said light source and said photoelectric tube relative to said feeding means.

4. In a device for continuously loading and counting sheets of paper or the like, means for maintaining the top of the constantly increasing load of sheets at or below a maximum predetermined level, a platform supporting the constantly increasing load, said platform being carried by platform raising and lowering mechanism, fixed level feeding means directing the sheets onto said platform, a source of light directed onto the edge of the sheets being loaded and onto the vertical face of the rising load at a predetermined level below the said feeding means, a light sensitive device comprising a photoconductive cell, said photo-conductive cell being activated by the increasing degree of light sensitivity on the edges of the sheets on the face of the rising load, the said source of light and photo-conductive cell being mounted on a common support bracket on said platform, the activation of said photoconductive cell setting in motion the lowering of said raising and lowering mechanism to lower said platform and its load to a point where the light intensity on the face of the load is decreased and the photo-conductive cell ceases to be activated, and means to adjust the level of the said light source and said photo-conductive cell relative to said feeding means.

5. In a device for continuously loading and counting sheets of paper or the like, means for maintaining the top of the constantly increasing load of sheets at or below a maximum predetermined level, a platform supporting the constantly increasing load, said platform being carried by platform raising and lowering mechanism, fixed level feeding means directing the sheets onto said platform, a source of light directed onto the edge of the sheets being loaded and onto the vertical face of the rising load at a predetermined level below the said feeding means, a light sensitive device activated by the increasing degree of light sensitivity on the edges of the sheets on the face of the rising load, the said source of light and said light sensitive device being mounted on a common support bracket on said platform, the activation of said light sensitive device setting in motion the lowering of said raising and lowering mechanism to lower said platform and its load to a point where the light intensity on the face of the load is decreased and the light sensitive device ceases to be activated, a time delay device associated with said raising and lowering mechanism, the said time delay delaying for a predetermined interval of time the activation of the platform raising and lowering mechanism by the light sensitive device, and means to adjust the level of said source of light and said light sensitive device relative to said feeding means.

References Cited in the file of this patent UNITED STATES PATENTS 2,317,652 Toney Apr. 27, 1943 2,319,287 Arendt May 18, 1943 2,525,311 Peyrebrune Oct. 10, 1950 2,606,297 Sweet Aug. 5, 1952 2,609,159 Nye Sept. 2, 1952 2,707,142 Waite Apr. 26, 1955 2,783,450 Jackson Feb. 26, 1957