US2914320A

US2914320A - Proportional folding machine and method

Info

Publication number: US2914320A
Application number: US586954A
Authority: US
Inventors: John R Petre
Original assignee: American Laundry Machinery Co
Current assignee: American Laundry Machinery Co
Priority date: 1959-08-17
Filing date: 1956-05-24
Publication date: 1959-11-24
Anticipated expiration: 1976-11-24
Also published as: GB886044A; NL122665C; FR1244952A; NL244946A; DE1208285B

Description

Nov. 24, 1959 Filed May 24, 1956 J R. PETRE PROPORTIONAL FOLDING MACHINE AND METHOD 4 Sheets-Sheet 1 INVENTOR. I (/0/7/7 A. Pe/re Nov. 24, 1959 J. R. PETRE PROPORTIONAL FOLDING MACHINE AND METHOD 4 Sheets-Sheet 2 Filed May 24, 1956 INVENTOR. John R. Fe fre I Afforn eys Nov. 24, 1959 J. R. PETRE 2,914,320

PROPORTIONAL FOLDI-NG MACHINE AND METHOD Filed May 24, 1956 4 Sheets-Sheet 3 1 INVEN TOR. John R Pefre Nov. 24, 1959 J. R. PETRE 2,914,320

PROPORTIONAL FOLDING MACHINE'AND METHOD Filed May 24, 1956 4 Sheets-Sheet 4 1 N V EN TOR. (/0/7/7 R Pe/re BY Won 9 m) A #0/77 eys United States Patent PROPORTIONAL FOLDING MACHINE AND METHOD John R. Petre, Cincinnati, Ohio, assignor to The American Laundry Machinery Company, Cincinnati, Ohio, a corporation of Ohio Application May 24, 1956, Serial No. 586,954

29 Claims. (Cl. 27068) The invention relates to a method and means for folding flexible flatwork articles. In one adaptation it finds particular use in the folding of laundered fabric material such as sheets and the like.

An object of the invention is to devise a novel and improved method and means for folding flatwork articles at proportional points relative to their length, as they are moved to and past a folding zone. This folding in accordance with the present invention is accurately effected regardless of variations in length of the successive articles, and is accomplished in accordance with an entirely novel folding principle.

A further object of the invention is to devise a method and means for progressively and continuously arranging a moving workpiece in proportionally folded parts preparatory to folding, as the article moves at or adjacent to a folding zone.

A further object of the invention is to devise a means and method as defined in the last preceding paragraph wherein, in an operation culminating in a double trans-' verse fold, the first three plies are progressively and continuously developed in the moving article, and, in combination therewith, additional means is provided for determining the exact time of executing the actual folding operation and lapping the last ply.

Another object of the invention is to devise a method of folding flatwork articles, and a means for execution of said method, which means occupies less than the normal amount of floor space, which requires no timers of conventional type, and no forwardly-located measuring switches of the usual type.

Other objects and advantages, as well as novel means for achieving the same, will be apparent as the description proceeds.

By way of an example, my invention will be described as applied to the proportional folding of a laundry flatwork article at the half and quarter points, although other flexible flatwork articles may be similarly folded, and at locations other than the half or quarter points, as will appear from the description of the selected embodiment.

In the drawings,

Fig. 1 is a vertical sectional view through a folding apparatus embodying my invention, the feed end or front end extending to the right, and the delivery end to the left.

Fig. 2 is a side-elevational view of the right side of the machine from the standpoint of the front or feed end.

Fig. 3 is a side elevational view of the left side of the machine.

Fig. 4 is a sectional view taken on the line 44 of Fig. 1.

Figs. 5 and 6 are sectional views taken respectively on the lines 55 and 6-6 of Fig. 4.

Fig. 7 is a sectional view taken on the line 7-7 of Fig. 6.

Fig. 8 is a top plan view of the folder rollers and cooperating proportional roll, but without a workpiece.

Fig. 9 is a top plan view of the mirror system from the position of the line 99 of Fig. 1.

Figs. 10, 11 and 12 are semi-diagrammatic views of 2,914,320 Patentedv Nov. 24, 1959 ice 2 the part of the folding mechanism in the immediate folding zone showing respectively successive stages in the folding operation.

Fig. 13 is a diagrammatic view showing the electrical and pneumatic circuits and certain associated patrs.

As seen in Figs. 1, 2 and 3, the machine structure includes

side frames

20, 21, connected by cross or

tie rods

22, 23, 24, 25, 26, a feed conveyor 27 and a delivery shelf or table 28. The feed conveyor comprises a set of spaced endless ribbons or belts 27 running on front roll 29 and rear roll 30. Roll 29 is journalled in cantilever type support arms 31, and roll 30 has gudgeons or end shafts 30a journalled in the side frames. A cross brace rod 32 carries ribbon guide fingers 33. The arms 31 are pivotally mounted on shafts 30a. Suspension springs 34 hold the conveyor assembly in operative position with the associated ironing machine, the ironer belt brackets 35 being in contact with rollers 36 extending from arms 31, so that the ironer brackets can be swung down during idle, slack apron periods. A pair of supporting

toggle links

37, 38 can be swung forward, over center around fixed pivot 38a, and down to allow the feed conveyor to swing down clockwise (Fig. 1) when desired to give access between the machines.

Another set of endless conveyor belts or ribbons 39 runs over roll 30, fitting in the spaces between belts 27. These endless ribbons 39 contact another set 40 which runs over a roll 41 superposed on roll 30 and over upper roll 42 superposed on a roll 43. Endless ribbons 39 run on this roll 43, then down to a roll 44, over roll 45' and back to roll 30. Another set of endless ribbons 46 runs in contact with the vertical stretch of ribbons 39, going over an upper roll 47, lower roll 48, roll 49 and rear rolls 50 and 51. Ribbon set 39 is aligned, in contact with

ribbon sets

40 and 46, and all travel at the same speed. Thus a workpiece will first feed off of the ironer delivery ribbons 35a onto the pickup or feed conveyor ribbons 27, enter between

ribbons

39 and 40 and be carried upward in run A, go around roll 43 guided by a by-pass director 52, enter between

ribbons

39 and 46 and be carried down run B and feed therefrom for the folding operation.

The by-pass device permits articles to be diverted from the folding route if required. A set of curved director fingers 52 normally fits between ribbons 40 where they go around roll 42, recesses being provided for the fingers by having the ribbon supporting portions of greater diameter than the main roll. When a piece is to be bypassed, the fingers 52 are swung down into recesses on roll 43, fitting then between ribbons 39 with the forward part of the fingers below the plane of the ribbons, so that the workpiece slides out over fingers 52 and down over fixed slide sheet 53 and down onto the delivery table. The guide 52 is carried by shaft 52a which is rockable by means of an arm 54 (Figure 2) operated by an air motor 55. A spring 56 normally holds the by-pass in retracted position. Air is supplied to motor by operation of slide valve 57, admitting air from supply branch pipe 58 to pipe 59.

Before going into further details of structure, a general characterization of the folding operation may be advantageous at this point. The workpiece, such as a sheet S, feeds down in ribbon run B, and when the leading edge is a few inches below the discharge point a roller-folder 60 swings forward and clamps the sheet against abutment fingers 61. The sheet continuing to feed down, loops a short distance over folder 60, and the abutment fingers then retract, the roller group 60 moves the sheet into contact with a proportioner roll 62- which feeds the forward part of the sheet down at a speed proportional to the main conveyor speed, in this case one-third. The sheet now has portions running downwardly on both sides of roll 60. Simultaneously a fixed-source light beam shines upward along conveyor run B, and when the trailing edge of the sheet clears the light beam, roller-folder retracts and air jets from the folder insert the sheet into the bite between ribbons 46 and roll 49. The rear quarter of the sheet feeds down and through the folding rolls as the first three quarter plles feed up off of roller-folder 60, and slide fingers 63, recessed in roll 49, guide the folded sheet onto the delivery table 28. A more complete explanation will 'be given later, in connection with the operational control.

The roller-folder is shown in detail in Figs. 4, 5, 6, 7. A tube or pipe 64 functions as a support for rollers 60, and as an air supply pipe. Pipe 64 is carried by a number of upright members 65 through sleeve pieces 66, uprights 65 being secured at their lower end in a supporting cross member 67 which is pivotally mounted in the side frames at 67a. As here shown pipes are used for upright supports. Only the two end pipes 65a are here utilized to carry the air supply, their upper connecting piece 66a providing communication with cross pipe 64. The intermediate connecting members 66 are merely socketed supporting sleeves having no air communication with pipes 65. Other sleeve or spacer members 66b are like 66 but without the pipe socket. All of the members 66 and 66b have a pair of air jet holes 68 registered with holes in pipe 64, set screws 69 holding the parts in non-rotatable alignment. The slender tubular upright supports 65, 65a permit a slight flexing to provide even seating contact between rollers 60 and driving rolls 62.

Alternating between the sleeve members are rollers 60. These may be made of a suitable synthetic resin, or they can be of light weight metal fabrication, to reduce rotational inertia. They are shown with bushings 60a fitting on bearing extension portions of members 66, 6611. Instead of this, small ball bearings or needle bearings could be provided.

What can be termed the proportioner roll comprises a shaft 62a with spaced driving roll sections 62 secured thereon as by a key. These roll sections 62 act as drivers for the workpiece and rubber or similar material is preferred, this possessing, in addition, sufiicient resilience to accommodate some variation in thickness of the workpiece. Secured internally of the resilient cylinder 62 is a metal mounting sleeve 62b, as shown in Fig. 1. Shaft 62a is journalled in the end frames, and rotated continuously.

The drive for the various rolls is shown in Fig. 3. An electric motor 70 with suitable speed reducing means drives a chain 71 from sprocket 72, the chain in

turn driving sprockets

73, 74, 75, 76, secured respectively to the shafts of

rolls

49, 48, 44 and 30. A sprocket 77 is compounded with and equal in size to sprocket 73, and drives a larger sprocket 78 through chain 79. Sprocket 78 is secured to proportioner roll shaft 62a and drives this roll at one third speed. compounded with sprocket 74 is an equal size sprocket 80 which drives a sprocket 8'1 by a chain 82. Sprocket 81 is somewhat larger than its driver, this being merely to compensate for a larger diameter of the roll 42 which it drives, all of the ribbons being driven at the same speed. Idler sprockets 83, 84 on adjustable arm 85 take up any slack in chain 82.

The bottom cross support 67 of the roller bar has a pair of operating arms 86. Two

cross rods

87, 88 have connected respectively thereto the piston rod clevis of an air motor 89 and a spring 90. The spring normally holds the roller bar in the position of Fig. 1, the rollers 60 slightly spaced from belts 46 and roll 49, a stop nut 91 and bumper washer on the piston rod of air motor 89 acting as a rear positioning means. The air motor, air flow paths, pressure, spring etc., are properly proportioned to operate the folder-roller bar correctly withoutjarring.

The arrangement for determining .the third. quarter fold 4 will now be described. Referring to Figs. 1, 9 and 13- a light source 92 in a suitable housing with reflector and lens 92a is mounted in fixed position on tie bar 22 of the frame, and directs a narrow, concentrated beam vertically downward. Positioned in the path of the beam is a small mirror 93 set at an angle of 45 to the beam and in line with a gap between the conveyor ribbons of downward run B. The mirror is mounted on a carrier 93a fastened to a pair of cooperating endless chains 94. The latter run on a pair of upper sprockets 95 and a lower pair 96, secured respectively to

transverse shafts

97 and 98. The shafts are journalled in the end frames and one is driven as later described. On the other side of conveyor run B, aligned with mirror 93, a relatively long, narrow mirror 99 is secured to a support 99a mounted on tie rods 23, 24. This mirror is positioned at 45 to the beam from small mirror 93, to direct the beam again horizontally but perpendicular to the first incident beam. Laterally spaced from mirror 99 is a similar mirror 100, secured to support 100a mounted on the tie rods. This mirror is set at 45 to the beam from mirror 99 and reflects the beam forward through another gap between the conveyor ribbons to a small mirror 101. The latter is secured to a carrier 101a fastened to a pair of chains 102 which run on an upper pair of sprockets 103 and a lower pair 104, secured respectively to

shafts

97 and 93. Mirror 101 directs the beam vertically upward into a photo-electric cell 105 housed in a suitable casing 105a mounted on tie rod 22. It will be observed that the light beam in its circuit between the first and fourth mirrors lies in one horizontal plane, and interruption of the beam by a workpiece moving through this plane deactivates the photoelectric control circuit.

Mirrors

93 and 101 are adapted to be moved in unison in axial alignment with the light source and photocell respectively, and

longitudinal mirrors

99 and 100 cooperate to thereby allow the control beam in what might be called the sensing plane to be moved or displaced at a required rate. Prisms having 45 totally reflecting internal or external surfaces may be substituted for mirrors herein.

It may here be pointed out, with reference for exam ple to Fig. 11, that the first quarter fold line will be located at the part of the sheet at the top of rollers 60, and the mid point will be located along the bottom of the depending loop to the left and below rollers 60, and, as previously stated herein, the first three overlaps ahead of the last quarter fold are continuously developed as the operation proceeds to the actual instant of effecting the fold. The timing of this instant, and the actual location of the last quarter fold, depends on the clearing of the trailing edge of the sheet past the horizontally rc flected light beam. The particular arrangement of light, photocell, and mirrors could be employed for making a mid fold only by removing the proportional roller folder and using an ordinary folding blade which is actuated once when the sensing light beam clears the trailing edge of the sheet.

The driving means for the mirror chains is as follows:

referring to Figs. 1 and 2--the mirror control parts as well as most of the other control parts are located on the outside of the right hand frame. The mirror chain drive is by the lower shaft 98. A comparatively simple means is illustrated which utilizes and cooperates with the other main driving means to provide a single, selfcontained control. As will later be apparent, the small mirrors must first travel upward at a speed one third that of the conveyors, then must return at full speed. Sprocket shaft 98 has secured to it a pair of disks or wheels 106 and 107, each having a rim faced with a material having a high frictional coefficient, or being grooved or otherwise roughened for the same purpose. Cooperating driving

wheels

108 and 109 are fastened on shafts 49a, 50a of rolls 49 and 50, and rotate continuously in the directions indicated. An intermediate or connector wheel 110 for co pling whee s .1. .nd.l9. .n9 .1 1y ou o con with both, as shown. Similarly, an intermediate wheel 1.11 is normally out of contact with associated

Wheels

109, 107. These connector wheels and driver wheels have, like the driven wheels, high-friction peripheries. Connector wheel 110 is journalled freely in a yoke or clevis 112 having an arm 113 joining it to a lever 115. The latter is freely pivoted on a stud 116 on the frame, and connects through a short link with the armature of a solenoid 117. A spring 118 normally holds these parts in unoperated position, lever 115 resting against a stop stud 119. Similarly, connector wheel 111 is freely journalled in a yoke 120 carried by an arm 121 secured on a lever or arm 122. The latter is freely pivoted on stud 116 and is not connected to lever 115. A solenoid 123 through a short link connects to the end of lever 122, and a spring 124 normally holds the parts in unoperated condition, lever 122 abutting stop stud 125.

When either solenoid 117 or 123 is energized, it causes its respective connector wheel to be swung into engagement with the associated driving and driven wheels. The pivot point 116 is located to effect accurate contact of the connecting or coupling wheel with the other two; and the arms 113 and 121 are of slightly flexible construction to further assure good driving contact of the three wheels in each case. Solenoid 117 when energized therefore causes sprocket shaft 98 to be rotated clockwise (in Fig. 2), moving the

mirrors

93 and 101 upward at one third the speed of the conveyors. This speed reduction is effected by the ratio of the diameters of driving and driven wheels 108, 106-the low speed proportioner roll 62 not being involved here. Energization of solenoid 123 causes the chain shaft to be rotated counterclockwise, moving the mirrors downward at full conveyor speed. Driver 109 is larger than the driven wheel 107, to compensate for the smaller diameter of the mirror chain sprockets.

The upper chain shaft 97 has fixed thereto a pinion 126 engaging a gear 127 journalled on a stud 127a on the frame. Secured to the gear is a switch actuator and stop member 128. When the folder is in idle position the piece 128 rests in contact with a stop screw 129 and holds the arm of a switch 130 depressed, for a purpose to be later explained; The pinion and gear reduce the maximum travel of the actuator member 128 to less than a complete revolution, the mirror chain sprockets making about three revolutions in moving the control mirrors during measurement of a maximum size sheet.

The sheet abutment members 61 are secured to a shaft 61a journalled in the end frames, and are adapted to be positioned either forward of the plane of the proportioning roll periphery or behind this plane, recessed between the roll sections. As shown in Fig. 8, these abutment fingers may be spaced between every second roll section, or they can, of course, be spaced either closer or farther apart. Referring to Fig. 2, shaft 61ahas secured to it an arm 131 and this is connected to a link 132 which in turn connects to a lever or modified bellcrank 133 pivotally supported on the frame at 133a. A solenoid 134 is connected by a short link to the link 132 and lever 133 at their connecting point. When the abutment fingers 61 are in extended position, as shown, solenoid 134 being deenergized, a spring 135 holds lever 133 with its back leg in contact with stop screw 136, the front leg and link 132 being in a straight line. This furnishes a solid abutment to hold the fingers 61out in stopping position. Energization of solenoid 134 breaks this toggle upward, and through arm 131 and the shaft, moves the stop fingers back to allow the roll sections 62 to engage the sheet. A stop screw 137 limits the movement.

A complete folding operation will now bedescribed.

drive is in neutral position, the mirrors at the bottom or starting position, stop member 128'resting against stop screw 129, and switch depressed. This is a normally closed switch, so it is now held open. The control light source is on, and the control beam is traversing its path from light 92 down to mirror 93, between conveyor belts B to mirror 99, laterally to mirror 100, forward between measuring set were used its light and photocell sections would preferably be spaced to divide the working width uniformly, the photocell and its mirrors being moved to the right of center.

The second control set includes a light source 292, mirrors, photocell and amplifier A(2) identical with the first described set, and it likewise normally energizes its relay R-2. The contacts of the two relays are in series and control operation of a third or main relay R-3, which is normally energized, as shown. The purpose of the extra control set is to cover the conveyor width with fairly close control beams so that even narrow workpieces will encounter a beam. However, in a single lane machine the articles, fed successively, could be fed into the ironer at zones which would ensure the cutting of one of the two beams of a single set. In either case, the laterally separated control beams, any one of which will actuate the control when interrupted, function also as a means for effecting an enclosed fold, that is, a fold with no protruding ends. An irregular sheet, or one not fed squarely, will actuate the control when the foremost corner of the sheet encounters a beam, and the control will remain energized until the rearmost corner of the sheet passes out of a beam.

Returning now to the present disclosure-relays R-1 and R2 are in normal energized condition and through them R-3, and the latter in turn holds time delay relay TD energized. Time delay relays TD and TD are unenergized due to the energized condition of coil R-3. Several time delay types are commercially'available, one kind functioning by inherent electrical characteristics, without any dashpots or other external delay means. Further, they can be had in either delayed-opening or delayed-closing forms. The three here used are of the delayed-closing type, i.e. when the coil circuit is closed an adjustable time delay ensues before the armature moves the contacts. The release is immediate.

All solenoids and solenoid-operated air valves are in unoperated condition. Now a sheet or other article feeds off of the ironer delivery belts 35a onto pickup conveyor 27, is carried up run A, then moving down run B the leading edge interrupts one or more of the light beams. Deenergizing the R-l, R-2 breaks the circuit to R-3, this circuit having been from L main switch S, lines 138, 139, contact armature of R-l, line 140, contact armature of R-2, line 141, coil of R3 and line 142 to main switch S and to L Deenergization of R-3 opens its contact R-3a and closes contact R-3b. The circuit through R3a had been holding TD energized as follows: L main switch SW, lines 138, 1143,. contact R-3a, line 144, coil of

TD lines

145, 146, 142, and switch S to L TD opens immediately, but with no effect. Closing of contact R-3b completes a circuit to TD and TD running from L switch SW, lines 138, 143, contact R-3b, lines 147, 148, coil T13 and

coil TD lines

149, 150, 146, 142 and switch to L Both relays are selected or adjusted to give a required time delay as mentioned. TD closes first and energizes coil 151 of solenoid air valve 152, the circuit going from L switch S, lines 138, 153, contact of 7 TD line 154, coil 151,

lines

155, 146, 142, switch S and L2.

Pipe 156 is connected by pipe 157 to an air source, and opening of valve 152, which is the usual combination inlet-outlet type, admits air under pressure from pipe 156 into pipe 158 and thence to air motor 89. The latter moves roller-folder 60 over to the position shown in Fig. 10, clamping the sheet between abutment members 61 and collar pieces 66b, 66 on the roller bar. The leading edge of the sheet has fed down a constant, predetermined distance during the interval of the time delay operation of TD this distance being such that the sheet is clamped a few inches in back of the leading edge. This assures full width engagement between rollers 60 and the sheet even if the edge is uneven or not square. Theoretically, engagement could take place right at the leading edge. However, the small overhang shown is not a disadvantage, the range in article length handled being similar to that for other common types of folders.

The sheet has been feeding down continuously, and now the portion depending from the feed ribbons drapes in a loop in the rear of the folder-roller bar. The other relay TD now operates its contacts, breaking at TD-a with no effect and closing TD-b to complete the following circuit: L switch S, lines 138, 153, 159, contact TD-b, line 160, solenoid 134,

lines

161, 162, 146, 142, and switch S to L Solenoid 134, as before described, causes abutment fingers 61 to retract, the sheet then being engaged between proportioning driver roll sections 62 and rollers 60 on the folder bar. Simultaneous with energization of solenoid 134, a circuit is made to solenoid 117, the circuit being the same up to line 160 then branching by line 163 to solenoid 117, thence by

lines

164, 146, 142 and switch S to L Solenoid 117 moves coupling wheel 110 into engagement with driver 108 and driven wheel 106, causing the mirror chain to move the

mirrors

93, 101, 293, and 301 up ward at speed.

Fig. 11 shows the point at which this retraction of abutments 61 and travel of the mirrors occurs. The relay TD gives a constant time delay such that the sheet has looped down approximately as shown at this point. The looped portion is slightly lower than the front por tion. This setting is used to compensate for the distance around the rollers 60 to the folding point, which is the line of air jets 68, with a bit more allowance to assure that the looped edge will be slightly in front of the other edges in the finished fold. This is desirable even when the previously described means is provided for taking care of uneven edges.

The initial position of the mirrors is such that the distance down to the folding point is substantially the same as the length of the depending portions, the exact setting being such as to take into account the constant factors of reverse swing time of roller bar 60 when the light beams clear the trailing edge, and the distance around the top of rollers 60. Therefore, with the sheet feeding down at a speed v, the proportioning roll 62 feeds the front portion down at of the conveyor speed,

The balance of the feeding velocity divides by looping, so that the bottom of the looped portion feeds down at so that at all times the distance from the mirrors to the horizontal folding plane is substantially the same as the distance from the depending edges to the folding plane. In this connection, it may be observed that since the first three plies of the fold are effected by the new proportioning roller device, the length of the mirror system is short, two to two and one-half feet normally.

When the Control beams clear the trailing edge of the sheet, relays R1, R-2 and R-3 are immediately re-energized. At R-3 this opens contact R-3b and closes R-3a. When R3b opens it breaks the previously traced circuits to TD and TD and these open immediately. At TD the circuit to air valve solenoid 152 is broken and the roller-folder bar is retracted by its spring 90. Simultaneously, opening of TD;, opens Contact TD-b and closes contact TD-a. Opening of TD-b breaks the circuit to solenoid 134, allowing abutment members 61 to again be extended. At the same time, opening of TD-b breaks the circuit to solenoid 117, disengaging the up drive to the mirror chains. Also, at the same time, closing of contact TD-a completes a circuit to the down" drive for the mirror conveyor. This runs from L switch S, lines 138, 153, 159, TD-a, line 165, switch (now closed), line 166, solenoid 123,

lines

167, 146, 142 and switch S to L This causes coupling wheel 111 to move into contact with driver 109 and driver wheel 107 to move the mirrors downward at full conveyor speed, immediately in back of the trailing edge of the sheet.

Closing of contact R-3a has closed the circuit, previously traced, to the coil of TD The contact of TD, is normally closed, and has been in this condition while the coil was deenergized. Now, when the .circuit to the coil is re-established, the contact remains closed during the time delay period, and a circuit is madeas follows: L switch S, lines 138, 143, R3a, lines 144, 168, relay contact of TD line 169 to coils 170, 171 of

solenoid air valves

172, 173 respectively. The circuit from coil 170 continues by

lines

174, 146, 142, and switch S to L From coil 171 the circuit goes by

lines

162, 146, 142 and switch S to L Operation of

air valves

172, 173 admits air under pressure from pipe 156 to

pipes

175 and 176 which connect flexibly with the two end pipes 65a of the folder-roller bar.

Note that all of these events described in the last two preceding paragraphs occur at the same time, immediately after the light beams clear the trailing edge of the sheet. As the folder bar drops back, the compressed air issues in a line of jets through apertures 68 and inserts the overlying two plies of material into the grip or bite formed by the rotating roll 49 and belts 46. Between these the sheet feeds out folded onto slide 63 and table 28. It will be noted that the combination of this roller folder with air jets has a practical advantagethc sheet is carried by the rollers into close proximity to the creasing rolls, inside the plane of their peripheries, so that a small thrust puts it into the grip of the rolls. The jets operate for a moment, predetermined by the delay time of TD When the relay pulls its contact open, the circuit to solenoid

air valves

172, 173 is broken.

The mirrors travel down in back of the trailing edge, and just before the starting station is reached, the actuator 128 contacts and opens switch 130, deenergizing solenoid 123 to terminate the mirror chain drive. The folder and its control are now in original condition, and can take care of another article closely following.

The lights 92 and 292 are on at all times while the control is in operation. The circuit to light 292 is from L switch S, lines 138, 177, lamp, lines 178, 142 and through switch S to L To lamp 92 the circuit is from L switch S, lines 138, 139, lamp,

lines

179, 146, 142, and switch S to L Obviously the arrangement hereinabove described does not necessarily require a vertically travelling arrange ment although the exemplification here shown represents one of the most convenient ways of accomplishing a double fold, and is presently preferred. My apparatus can effect a three-ply fold, for example the leading edge may be clamped by clockwise (Fig. 1) swing of the fold ing roller, the proportional roll being inactive in this case, and the leading portion of the loop depending to the left of the folding roll can then, of course, move downwardly from the folding zone while the mirrors move upwardly therefrom. In this instance, with the article feeding at a speed v, the mirror or other refleeting means will be moving at a speed When the mirrors clear the trailing edge of the sheet, a counter-clockwise swing of the folding roll will place the original leading edge in registration with the second one-third fold line, resulting in a lapped three-ply fold. If the original leading edge is clamped a little over top center on the folding roll, it will retain its position during the short swing of the folding roll to folding position, or the clamping device may be on the folding roll itself, and may be released as the air blast is turned on to insert the fold line in the pinch rolls.

My proportioning principle can also be used for effecting a half point single fold. In this case the control beam is fixed in position close to the folding point, preferably just above the folder roll bar or folding blade.

The proportioner roll is rotating at half speed instead of one third speed. When the leading edge of an article breaks the control beam, the folder bar swings over and clamps, as in Fig. 10, and the article then feeds down in a loop for a couple of inches, half the length of the front portion, whereupon the proportioner roll takes over. The front portion now feeds down at half speed, and the looped part feeds down at one-half of one-half or one-fourth speed therefore. Thus at all times the looped portion is only half as long as the front portion. When the trailing .edge clears the conveyor and light beam the looped portion drops, and the back portion is then equal in length to the front portion. The bar or blade with the article draped thereon swings back and the article is inserted into the creasing and delivery rolls. The article is then drawn up and off of the folder bar in this arrangement, requiring some spacing between articles.

From a consideration of the above-disclosed method and apparatus, it will be apparent that the invention in its essentials consists of advancing a flexible flat article towards and past a folding zone at a basic conveyor speed and intercepting a leading portion of the article in the neighborhood of the folding zone and advancing it at a second speed which is slower than said basic speed but bears a fractional relationship thereto. As a result of slowing down the leading portion of the article excess material will accumulate at an intermediate point and this is caused to drape in a two-ply loop of which the material is continually moving forward, but both the loop and the leading portion progressively develop and increase in length While still bearing to each other a proportional dimensional relationship. In the embodiment specifically illustrated and described, the loop and the leading portion are of substantially equal dimensional extent as a result of the selection of relative speeds for the leading and trailing portions of the article. The proportionate advance is terminated when the article has been developed into the desired number of equi-sized sections.

In the specific embodiment illustrated in the drawings, I have shown a preferred arrangement wherein the light source and the light sensitive cell are fixed in place, and movable reflecting means on the same side of the conveyor cooperates with a'second reflecting means on the opposite side of the conveyor to effect the necessary traverse and reverse travel of the light beam. The inventive purpose could be accomplished by eliminating the first above-mentioned reflecting means and disposing the light source and light sensitive cell to be movable rearwardly in a common plane at right angles to the path of travel, but always in operative alignment with the longitudinally extending reflecting means on the opposite side. The light source and the cell could be placed on a rack or bar carried by the travelling chains, or could even be carried directly on the rearwardlymovable flights of the chains. Such arrangement would require care in maintaining the necessary electrical contacts for the movable elements, and I prefer the specific construction illustrated herein.

What I claim is:

1. A method of dividing a flat flexible article along proportionately spaced transverse folding lines as the article advances along a path past a folding zone, said method comprising reducing the advance speed of a leading portion of said article at and beyond said folding zone while maintaining the advance speed of a trailing portion of the article as it approaches said folding zone whereby to cause an intermediate portion of the article to drape in a two-ply loop in the vicinity of the folding zone, and continuously and progressively increasing the length of said leading portion and said looped portion while maintaining substantially a constant ratio between the lengths of said leading portion and said looped portion.

2. A method of folding a flat flexible article in a manner as defined in claim 1 wherein the said leading portion and said two-ply looped portion are overlapped in finishfolded condition when they arrive at a predetermined proportional relationship with respect to each other and to the complete article.

3. A method of folding a flat flexible article as defined in claim 1 wherein the folding operation is consummated when the distance from the folding zone to the trailing edge of the trailing portion is equal to the distance from the folding zone to the leading edge of the leading portion.

4. A method as defined in claim 1 wherein the rate of advance of said leading portion of the article bears a fractional proportional relationship to the rate of advance of said trailing portion of the article, whereby to control the dimensional character of said loop with respect to said leading and trailing portions.

5. A method of folding a flat flexible article along folding lines proportionate to the length of the article comprising advancing the article along a path past a folding zone, reducing the speed of advance of a leading portion of said article as it passes said folding zone while maintaining the speed of advance of a trailing portion of said article towards said folding zone whereby to cause an intermediate portion of the article to drape in a twoply loop in the vicinity of the folding zone, continuously and progressively increasing the length of said leading portion while maintaining a constant ratio between the length of said leading portion and said looped portion, and finally executing a folding operation by overlapping said leading portion, said two-ply loop, and said trailing portion at the moment when the distance from the folding zone to the leading edge of said leading portion equals the distance from the folding zone to the trailing edge of the trailing portion.

6. A method as defined in claim 5 wherein the rate of advance of said leading portion of the article bears a fractional proportional relationship to the rate of advance of said trailing portion of the article, whereby to control the dimensional character of said loop with respect to said leading and trailing portions.

7. Apparatus for performing a folding operation proportionate to article length on a flexible flat article cornprising means defining a folding zone, article advancing means for moving said article towards and past said folding zone vat a-first speed, proportionate advancing means adjacent said folding zonedisposed to contact a leading portion of said article and produce continued advance thereof at a second speed, said second speed being slower than said first speed but bearing a fractional proportionate relationship thereto whereby to cause an intermediate portion of said article to accumulate in a two-ply loop, and whereby during movement of said article said leading portion and said loop develop continuously and progressively in respective sections which bear a constant dimensional ratio to each other, and means for disposing said sections in lapped contact and delivering the thus folded article from the folding zone when .the complete article is defined in respective equal-length sections.

8. Apparatus for performing a folding operation proportionate to article length on a flexible flat article compris ng means defining a folding zone, article advancing means for moving said article towards and past said folding zone at a first speed, proportionate advancing means adajacent said folding zone disposed to contact a leading portion of said article and produce continued advance thereof at a second speed, said second speed being slower than said first speed but bearing a fractional proportionate relationship thereto whereby to cause an intermediate portion of said article to accumulate in a twoply loop, and whereby during movement of said article said lead ng portion and said loop develop continuously and progressively in respective sections which bear a constant dimensional ratio to each other, means sensitive to passage of the article thereby, and means operatively responsive to said sensitive means for disposing said sections in lapped contact and delivering the thus folded article from the folding zone when the complete article is defined in respective equal length sections.

9. Apparatus for performing a folding operationproport onate to article length on a flexible flat article comprising means defining a folding zone, article advancing means for moving said article towards and past said folding zone at a first speed, proportionate advancing means adjacent said folding zone disposed to contact a leading portion of said article and produce continued advance thereof at a second speed, said second speed being slower than said first speed but bearing a fractional proportionate relationship thereto whereby to cause an intermediate portion of said article to accumulate in a two-ply loop between said leading portion and the trailing portion of said article, and whereby during movement of said article said leading portion and said loop develop continuously and progressively in respective sections which bear a constant dimensional ratio to each other, and means for terminating article advance and delivering a folded article from said folding zone comprising a folding member, means for moving said folding member transversely across the path of travel of the article along the line of demarcation between said loop and said trailing portion of the article, and means for simultaneously terminating advance movement of said leading portion of said article by said proportionate advancing means.

10. Apparatus for performing a folding operation proportionate to article length on a flexible flat article comprising conveyor means for advancing the article on a path towards and past a folding zone at a first speed, a reciprocable article-engaging member movable transversely across said path at said folding zone, means responsive to passage of the leading edge of the article thereby for swinging said article-engaging member across said path in one direction to thereby permit a leading portion of the article to be positioned on one side of said member and an intermediate portion of the article to advance in a two-ply loop on the other side of said member, proportional speed driving means adapted to be operatively engageable with said leading portion of saidarticle for advancing said leading portion at a second speed, slower than said first speed, but bearing a fractional speed proportional relationship thereto, whereby said leading portion and said loop advance in step with each other in progressively developing proportional lengths, and means for producing another swing of said article-engaging member across said path in reverse direction and delivering said article from said folding zone when said loop and said leading portion bear a predetermined dimensional relationship to the total length of the article.

11. Apparatus for performing a folding operation proportionate to article length on a flexible flat article comprising conveyor means for advancing the article on a path towards and past a folding zone at a first speed, a reciprocable article-engaging member movable transversely across said path at said folding zone, means for swinging said member across said path in one direction to thereby permit a leading portion of the article to be positioned on one side of said member, while an intermediate portion of the article advances in a two-ply loop on the other side of said member, and the trailing portion of the article continues its advance towards said folding zone, proportional speed driving means disposed to be contacted by said leading portion of said article following swing of said member as aforesaid for advancing said leading portion at a second speed bearing a fractional proportional relationship to said first speed whereby said leading portion advances in step with said loop in progressively developing proportionate lengths, control means movable rearwardly along said path away from said folding zone in a direction opposed to the direction of advance of said trailing portion, means responsive to passage of the leading edge of the article past said control means for initiating movement of the control means away from the folding zone simultaneously with movement of the leading edge of said leading portion away from the folding zone in the other direction, and at a speed equal to the speed of said leading edge portion, and means for producing reverse swing of said article-engaging member when said control means passes the trailing edge of the article.

12. Apparatus as defined in claim 10 wherein means is provided for temporarily holding the leading edge of the article upon first swing of said article-engaging member to permit initial formation of said loop, and for thereafter simultaneously releasing the holding means and activating the proportional speed driving means.

13. Apparatus as defined in claim 11 wherein means is provided for temporarily holding the leading edge of the article upon first swing of said article-engaging member to permit initial formation of said loop, and four thereafter simultaneously releasing the holding means and activating the proportional speed driving means.

14. Apparatus as defined in claim 13 wherein means is provided for simultaneously releasing the holding means and instituting reverse movement of said control means.

15. Apparatus as defined in claim 11 wherein the control means consists of a light source, means for projecting said light source across the path of travel of the article, means sensitive to impingement of said light beam and operatively effective on said article engaging member to produce operation thereof when the light beam clears the leading or trailing edges of the article, and means for constantly maintaining said light source, said beam, and said sensitive means in operative alignment.

16. Apparatus as defined in claim 10 wherein said article engaging member is swingable towards and away from a pair of cooperating folding rolls, and wherein said article is inserted in the bite of said folding rolls upon reverse swing of said member.

17. Apparatus as defined in claim 16 wherein said article-engaging member is provided with means for delivering a series of linearly aligned air jets whereby to deliver said article to the bite of said folding rolls.

18. Apparatus for performing a folding operation proportionate to article length on a flexible flat article comprising means defining a folding zone, article advancing means for moving said article towards and past said fo ding-zone at .a first speed, pr portionate advanc m means adjacent said folding zone disposed to contact a leading portion of said article and produce continued advance thereof at a second speed, said second speed being slower than said first speed but bearing a fractional proportionate relationship thereto whereby to cause an intermediate portion of said article to accumulate in a two-ply loop, and whereby during movement of said article said leading portion and said loop develop continuously and progressively in respective sections which bear a constant dimensional ratio to each other, and operating means for disposing said sections in lapped contact and delivering the thus folded article from the folding zone when the complete article is defined in respective equal length sections, said operating means including a control device, means for moving said device along said path in a direction opposed to the direction of advance of the trailing portion of said article and on the other side of said folding zone from said leading portion, and means for maintaining said device and the leading edge of said leading portion equidistant from said folding zone.

19. Apparatus as defined in claim 18 wherein said control device is activated to cause operation of said operating means when said device passes the trailing edge of said article.

20. Apparatus as defined in claim 18 wherein said device and the leading portion of said article are travelling at equal rates of speed, in opposite directions.

21. Means for controlling the performance of a folding operation proportionate to article length on an article moving along a path to and through a folding zone wherein a folding member executes a folding movement when the trailing edge of the article clears a light beam traversing said path, said means comprising a light source on a first side of said path adapted to emit a light beam, a first reflecting means on said first side of said path disposed to intercept said beam and divert it towards said path and, when unobstructed, through said path to a second side thereof, a second reflecting means on said second side disposed to intercept said beam and return it through said path, when unobstructed, back to the first side of said path, and a third reflecting means adapted to intercept the returned beam and divert it towards light sensitive means whereby to activate the same, the aforesaid member being operatively responsive to activation of said light sensitive means whereby to execute a folding movement when the trailing edge of the article clears said light beam so as to permit its double traverse of said path.

22. Control means as defined in claim 21 wherein said first and third reflecting means lie in a common plane perpendicular to said path.

23. Control means as defined in claim 22 wherein means is provided for simultaneously moving said first and third reflecting means along said path and away from said folding zone in a direction opposite to the direction of movement of said article.

24. Control means as defined in claim 23 wherein said second reflecting means is elongated in the direction of said path whereby to be always in position to intercept and return said beam regardless of movement of said first and third reflecting means.

25. Control means as defined in claim 21 wherein said second reflecting means consists of a pair of reflectors oriented to divert said beam from one to the other before returning said beam across said path.

26. Means for controlling the performance of a folding operation proportionate to article length on an article moving along a path to and through a folding zone comprising article advancing means for moving said article towards said folding zone at a first speed, proportionate advancing means adjacent said folding zone disposed to contact a leading portion of said article and produce continued advance thereof at a second speed slower than said first speed but bearing a fractional proportionate relationship thereto whereby to cause an intermediate portion of said article to accumulate in a two-ply loop, and whereby during continued advance of said article said leading portion and said loop develop continuously and progressively in respective sections which bear a constant dimensional ratio to each other, a light source on a first side of said path adapted to emit a light beam, a first reflecting means on said first side disposed to divert said beam through said path when unobstructed, a second reflecting means on a second side of said path disposed to intercept and return said beam, when unobstructed, light sensitive means on said first side of said path disposed to intercept and be activated by said returned beam, folding means in said foldingzone, means operatively linking said light sensitive means and said folding means whereby, when said light sensitive means is activated, said folding member performs a folding operation, said light sensitive means being activated as aforesaid when the trailing edge of said article clears the light beam at its zone of double traverse of the path.

27. Control means as defined in claim 26 wherein said first reflecting means is movable rearwardly along the path of travel away from said folding zone simultaneously with movement of said leading portion of said article forwardly from said folding zone, and at the same rate of speed, whereby, when the trailing edge of the article clears the light beam the leading portion and trailing portion of the article are of substantially equal length so as to be coextensively lapped by operation of said folding member.

28. Means for controlling the performance of a folding operation proportionate to article length on an article moving along a path to and through a folding zone comprising article advancing means for moving said article towards said folding zone at a first speed, proportionate advancing means adjacent said folding zone disposed to contact a leading portion of said article and produce continued advance thereof at a second speed slower than said first speed but bearing a fractional proportionate relationship thereto whereby to cause an intermediate portion of said article to accumulate in a two-ply loop, and whereby during continued advance of said article said leading portion and said loop develop continuously and progressively in respective sections which bear a constant dimensional ratio to each other, means on a first side of said path for producing a light beam and projecting it transversely across said path, when unobstructed, reflector means on a second side of said path for receiving such beam and returning it across said path, when unobstructed, light sensitive means on said first side disposed to intercept said returned beam and to be activated thereby, a folding member in said folding zone, and means operatively linking said light sensitive source and said folding member whereby said folding member executes a folding operaion when the trailing edge of said article clears said light beam.

29. Control means as defined in claim 28 wherein means is provided for moving said transverse portion of said light beam rearwardly away from said folding zone simultaneously with movement of said leading portion of said article forwardly from said folding zone, and at the same rate of speed, whereby, when the trailing edge of the article clears the light beam, the leading portion of the article, the trailing portion of the article, and the two-ply loop are all of substantially equal length so as to be co-extensively lapped by operation of said folding member.

References Cited in the file of this patent UNITED STATES PATENTS 1,088,456 Schefer Feb. 24, 1914 2,015,550 Elberty Sept. 24, 1935 2,725,228 Seward Nov. 29, 1955 2,770,457 Jesus Nov. 13, 1956