US 3147872 A
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Sept. 8, 1964 J. E. OLSON 3,147,872
SUCTION APPARATUS FOR PICKING UP VARIOUS SHAPED ARTICLES, ESPECIALLY PAPER ROLLS Filed Oct. 24. 1960 7 Sheets-Sheet 1 INVENTOR. John E. Olson Buckhorn, Chearham '8 Blore ATTORNEYS P 3, 1964 J. E. OLSON 47,
SUCTION APPARATUS FOR PICKING UP VARIOUS SHAPED ARTICLES, ESPECIALLY PAPER ROLLS Filed Oct. 24, 1960 7 Sheets-Sheet 2 o o o 3 o g; a o o I fig W a 263 w o O 3i H O 233 e l T 0 1 2 225 $1 2 W o w 22\ 6 l am 2'3 ze5 I 2O 5 I65 20| 269 |s3 3 -|6? -ls3 o 0 o $0 j P79. 4 INVENTOR.
I John E. Olson Buckhorn, Cheatham 8 Blore ATTORNEYS Sept. 8, 1964 3,147,872
- J. E. OLSON SUCTION APPARATUS FOR'PICKING UP VARIOUS SHAPED ARTICLES, ESPECIALLY PAPER ROLLS Filed Oct. 24. 1960 7 Sheets-Sheet s Fly. 6
(ON TRUCK) I63 H9- M 9 INVENTOR.
John E. Olson Buckhorn, Cheatham 8 Blore ATTORNEYS Sept. 8, 1964 J. E. OLSON 3,147,372
SUCTION APPARATUS FOR PICKING UP VARIOUS SHAPED ARTICLES, ESPECIALLY PAPER ROLLS Filed Oct. 24. 1960 '7 Sheets-Sheet 4 :1 uuuuc 287/ nu: 335 Jun 300%) 0 333 l2 i I INVENTOR.
John E. Olson m Buckhorn, Cheatham 8 Blore H ATTORNEYS Sept. 8, 1964 OLSON 3,147,872
SUCTION APPARATUS FOR PICKING UP VARIOUS SHAPED ARTICLES, ESPECIALLY PAPER ROLLS Filed Oct. 24. 1960 7 Sheets-Sheet 6 TO VACUUM PUMP III VACUUM ON 25 22 3s? gai 387 V TO VACUUM OFF PUMP Fig. 23
VACUUM Fly. 24
John E. Olson BY Buckhorn, Cheatham 8 Blore ATTORNEYS United States Patent 3,147,872 SUCTION APPARATUS FOR PICKING UP VARIOUS SHAPED ARTICLES, ESPECIALLY PAPER ROLLS John E. Olson, Portland, 0reg., assignor to Hyster Company, Portland, 0reg., a corporation of Nevada Filed Oct. 24, 1960, Ser. No. 64,639 3 Claims. (Cl. 214-652) This invention relates to a suction apparatus and method for picking up articles ofv commerce, particularly paper rolls, such as heavy rolls of newsprint paper, kraft paper and the like.
In the past, it has been the practice to pick up a paper roll by a clamp device on the front of a lift truck. Such a device is complicated and quite expensive. I
It is a main object of the present invention to provide a method of picking up a paper roll which makes use of subatmospheric pressure, and to provide a simple and relatively inexpensive apparatus by which the method can be carried out.
Despite the fact that it is quite old to handle and pick up rigid articles of commerce by means of suction heads, prior to the present invention, no one apparently thought it possible to pick up a heavy roll of paper by means of a suction head means. Apparently, it was thought obvious that the outer loop of paper would simply tear off. Also, apparently the end edges of the roll are not normally sealed and obviously air could enter, it was thought, between the loop and the remainder of the roll to make lifting the roll an impossibility.
Sometimes a roll of paper is enclosed in a wrapper. It was apparently also thought obvious that such a wrapper was not strong enough to support the roll or enable it to be lifted, and in addition the wrapper frequently was punctured and it was apparently thought that this would make it impossible to lift the roll. Still further, it is sometimes the practice in the industry to fasten the outer end of the paper of a roll in place by one or two adhesive pieces, leaving the remainder of the end edge unsecured. Obviously, it was thought, air could readily enter between such unsecured portions and the next inner loop making suction lifting possible. Also, sometimes, the outer end becomes unsecured, and while this does not prevent handling by a clamp, apparently it was thought that this would prevent the roll being lifted by any suction means.
I have discovered that a roll of paper can be picked up by a suction head means provided only that the outer loop or wrapper at the location of the head tightly lays against the material underneath at the time of application of suction. I have discovered that even though the outer end is totally unsecured, the roll may be successfully picked up by a suction head means, without tearing the outer loop or wrapper or otherwise damaging the roll.
I have further discovered that even if the outer loop is loose or the wrapper is loose, if the application of suction is withheld until the outer loop or wrapper is pressed against the remainder, the roll can be picked up, with the atmospheric pressure forming a pressure seal between the roll and the sealing means of the suction head.
I have further discovered that with certain kinds of paper, when picking up a roll of paper by a suction head means, there apparently is suificient air entrapped within the loops of the roll to puncture a loop or loops in the area of the suction head. I have further discovered that if the area of the roll defined by the suction head means is prevented from movement away from the remainder, this puncturing can be prevented.
It is therefore an object of the present invention to provide a method of picking up a roll of paper comprising creating a subatmospheric pressure over a selected area of the exterior surface of the roll, prior to creating the subatmospheric pressure, making certain that such surface is tightly against the underlying portions of the roll, and preventing such exterior surface in the selected area from separating movement from such remainder.
In developing the method of the present invention, I have discovered a novel apparatus by which the method may be carried out, and have further discovered devices useful in lifting apparatus in general.
A main object of the invention is to provide a suction apparatus for picking up a roll of paper or similarly shaped object.
A further object is to provide a suction lift apparatus having a novel load contacting means capable of adjusting to the contour of the object to be picked up.
Another object is to provide a novel means of controlling the movement of a plurality of load contacting devices.
A further object is to provide a suction lift apparatus having novel valve means for controlling the communication of the suction heads to the source of vacuum.
Another object is to provide a suction lift attachment for an industrial lift truck which is mounted for movement on the mast of the truck in a novel manner to facilitate more ready and proper contact between the suction lift attachment and the roll.
Another object of the invention is to provide a suction lift attachment for an industrial lift truck which is mounted for rotary movement about a longitudinal axis so as to up end a roll.
Another object of the invention is to provide a novel sealing means for a suction vacuum head.
Various other objects of the invention will be apparent from the following description taken in connection with the accompanying drawings, wherein:
FIG- 1 is a side view in elevation of a lift truck showing in diagrammatic form an attachment of the present invention;
FIG. 2 is a plan view of the structure disclosed in FIG. 1;
FIG. 3 is. a side view in elevation showing the roll attachment as having been rotated degrees in position for picking up. a roll in a horizontal position;
FIG. 4 is a front view of the suction apparatus but being much less diagrammatic than FIGS. 1, 2 and 3', parts being broken away for convenience in illustration;
FIG. 5 is a plan view of the attachment of FIG. 4, parts being broken away and other portions being shown in section, for instance, on line 5--5 of FIG. 4 to show the manner of mounting. certain suction heads;
FIG. 5a is a sectional view taken along line 5a--5a of FIG. 5;
FIG. 6 is an enlarged vertical section taken along line 66 of FIG. 4;
FIG. 7 is an enlarged sectional view along line 7-7 of FIG. 4;
FIG. 8 is a side view of the structure shown in FIG. 4;
FIG. 9 is a sectional view taken along line 99 of FIG. 8;
FIG. 10 is a front elevational view of suction head 41;
FIG. 11 is a vertical section taken along line 1111 of FIG. 10;
FIG. 12 is a horizontal section taken along line 12-12 of FIG. 11;
FIG. 13 is a horizontal section taken along line 1313 of FIG. 10;
FIG. 14 is a sectional view taken along line 14-14 of FIG. 13;
FIG. 15 is a sectional view taken along line 15-15 of FIG. 10;
FIG. 16 is a schematic view of part of the suction system for the suction head;
FIG. 17 is a diagrammatic view of a modified form of suction system for the heads;
FIG. 18 shows another modified form of suction system for the head;
FIG. 19 is a vertical section through one of the apron valves;
FIG. 20 is an end view of the valve of FIG. 19;
FIG. 21 is a view similar to FIG. 19 but showing the valve unit as having been shifted to a second position;
FIG. 22 is a midsection through a modified form of valve;
FIG. 23 shows the same valve in a ditferent operative position;
FIG. 24 shows the valve in a subsequent stage of operation;
FIG. 25 is a sectional view taken along line 25-25 of FIG. 22;
FIG. 26 is a diagrammatic view of part of the hydraulic circuit for the attachment; FIG. 27 shows the head plate of one suction section in its operative position in contact with a roll; and
FIG. 28 is a diagrammatic view showing the suction heads against a roll having a loose end.
GENERAL DESCRIPTION Referring to the drawings and particularly to FIGS. 1 and 2, the lift truck 21 has a mast 23 at the front end. A load carriage of the present invention is mounted by rollers 25 in the mast for movement therealong under the influence of a lift mechanism, such as a hydraulic ram 27 shown in FIG. 2.
The load carriage includes as primary elements a carriage unit 31 having the rollers 25, a base member 33 mounted on the carriage for limited pivotal movement by a connection 34, a revolving apron 35 rotatably mounted on the base member, and a plurality of suction heads, two pairs being shown and numbered 37 and 39 and 41 and 43 (FIG. 2). The heads are mounted on the apron, in a manner to be presently described, for adjustable movement of various types for proper engagement with a paper roll R.
If the roll to be picked up is in a horizontal position as shown in FIG. 3, the suction heads can be rotated 90 degrees to adapt them for proper engagement with the roll. It is also obvious that a roll picked up in a vertical position of FIG. 1 can be revolved to the horizontal position of FIG. 3 for deposit in a horizontal position if desired. The device of the present invention has specific features to facilitate proper support of a roll by the suction heads when the roll is rotated.
Referring to FIG. 1, the suction heads 37-43 are connected to a source of suction on the truck body, such as a vacuum pump 51, by a hose or conduit 53. The hose 53 extends from the pump forwardly past a control valve 55, and then over a slack take-up sheave 57 mounted on the inner movable uprights of the mast, and then extends downwardly and through the rotary connection between the base member 33 and the apron 35. A manifold arrangement connects the hose to the suction heads.
In operation, as the heads are brought into engagement with a roll, the valve 55 is operated to connect the suction heads to the suction pump 51 so that atmospheric pressure forces the roll against the heads with sufiicient force to enable the carriage to be elevated to lift the roll.
SPECIFIC DESCRIPTION Base Member Mounting Referring to FIGS. 5, a and 8 the connection 34 is at the upper portion of the'base member 33 (FIG. 8) which comprises a flat circular plate (barely visible in FIG. 8).
The connection 34 comprises a universal joint having a socket member 101 (FIG. 5a) carried by a lug 103 provided on the rear of the base member 33 (FIG. 5). The socket member has a ball member bored to receive a pin 109, the ends of the latter fitting in holes in a clevis fixed to the upper end of a cross piece 111 of the carriage unit 31. The spaces between the clevis and the lug allow for pivotal movement of the base member relative to the carriage unit about a vertical axis. A pair of laterally spaced stop elements 115 (FIG. 5) adjustably thread into the carriage unit and limit such pivotal movement.
The base member can also pivot rearwardly on the connection 34. Referring to FIGS. 1, 8 and 9, to control such pivotal movement there is provided a pair of spring assemblies, each including a compression spring 119 surrounding telescoped elements 121 and 123 pivotally connected at 125 to the base member 33 and at 127 to the carriage unit 31, respectively. The springs make a small acute angle With the vertical. Hence, the springs are compressed only slightly by substantial rearward movement of the lower portion of the base member. Thus, while rearward movement of the lower portion of the base member is resisted by the springs, it takes only a relatively small increase in force to so move the base member because of the angular relationship of the parts.
Referring to FIGS. 5, 8 and 9, at the bottom of the base member 33 there is a link 129 pivotally connected at 131 to the base member and at 133 to the carriage unit. The link is operable to prevent turning movement of the base member 33 about an axis extending longitudinally of the truck.
Apron Mounting The apron 35 essentially comprises a generally flat generally rectangular plate having a revolving connection between the apron and the base member 33, which connection in FIGS. 1 and 2 is shown in diagrammatic form. In practice, the connection is generally like that shown in the Ehmann Patent 2,959,131. Thus, referring to FIGS. 5 and 8 of the present application, there is an annular row of bearings 135 between the base member 33 and an annular flange 139 on the apron 35. Referring now to FIGS. 5, 6 and 8, a pair of cylinders 141 fixed on the base member have pistons 142 equipped with rack teeth to drive a pinion 143. The pinion is secured by bolts 145 to the apron 35. Suitable housing members 147 (FIG. 5) are provided for the ends of the cylinders 141.
The hydraulic conduits or hoses between the truck and the cylinders 141 are not shown, but may be of conventional form. These hoses extend from the truck over suitable slack take-up devices, not shown, and then lead to the carriage unit and connect to suitable fittings (not shown) mounted on the carriage unit 31. Short hose sections (not shown) extend from the fittings to the cylinders 141.
Suction Head Mounting The mounting of each pair of suction heads is the same, and so only one mounting will be described. Referring to FIGS. 5 and 11, the heads 41 and 43 each includes an elongated, rigid base plate member 161 (FIG. 11) having clevis lugs 163 at the upper and lower portions connected by pivot pins 165 (FIG. 5) to the opposite ends of a pair of mounting links 167. Each link is pivotally mounted at its central portion by a pin 169 to a pair of clevis lugs 171 fixed to the front of the apron 35, or fixed to a detachably mounted plate or bracket, not shown, if desired.
As best shown in FIG. 5, each end of each mounting link has a flat front end edge 181 angularly intersecting a flat front intermediate edge 183. As the head 43 is shown in FIG. 5, the edge 181 is disposed next to the plate member 161 of the head and intersects the edge 183 at a place so that the head 43 may pivot from the position shown a limited extent in a clockwise direction relative to the associated links. The edges 181 and 183 thus limit pivotal movement of the head relative to the links, but the absolute pivotal movement of the heads is greater and includes the pivotal movement of the mounting links themselves.
As the head 41 is shown in FIG. 5, the edge 183 is disposed next to the plate member of the head, and thus the head 39 may pivot a limited extent in a clockwise direction. The angular movement of the heads 41 and 43 relative to the links, in the particular embodiment of the invention shown, is in the order of 20 to 25 degrees.
Hydraulic Control System for Suction Heads A hydraulic circuit is provided in association with the mounting links to control their pivotal movement. Referring to FIGS. 5 and 26, the circuit includes a cylinder 201 for each link 167 pivotally mounted on the clevis 171 by a pin 203 as shown in FIGS. 4 and 5. The cylinder has a piston 205 (FIG. 26) equipped with a rod 207 having a sleeve 209 (FIG. 4) receiving the pivot pin 165, previously mentioned.
Referring to FIG. 26 each cylinder has its rod end hydraulically connected by a separate line 211 to an intermediate portion of a separate passage 213 in the valve body 214 of a check valve unit. The body is mounted on the apron 35 (FIG. 4) and includes a pair of check valves 215 and 217 (FIG. 26) for each passage 213. The check valves are disposed on the opposite sides of the lines 211 and open in the same direction. A common line 219 connects all the check valves 215 to an accumulator 221 mounted on the apron 35 (FIG. 4), and a common line 223 connects all the check valves to a solenoid valve 225 also mounted on the apron (FIG. 4). The solenoid valve is connected to the line 219 by a line 227.
Referring to FIGS. 4, 6 and 26, there is a vacuumoperated switch 231 mounted on a hollow suction T 233 (FIG. 6) and connected by a conductor 235 (FIG. 26) to the solenoid valve 225. The switch 231 is grounded on the apron 35, and a live conductor 237a (FIG. 6) connects the valve 225 to a terminal 239 on the T 233. A conductor 23711 is connected to the terminal and extends through the suction conduit 53 to a terminal 241 on the trucks. A conductor 237a connects terminal 241 to the battery 243 (FIG. 26) of the truck. The conductors 237a, 237b and 2370 may be considered as constituting a single conductor 237.
The vacuum switch is responsive to a predetermined vacuum in the suction T 233 to energize the solenoid valve and close off communication between the lines 223 and 227. In one unit, the vacuum switch was responsive to a vacuum of seven inches of mercury to energize the solenoid valve.
Referring to FIGS. 5 and 26, in operation, the accumulator 221 creates sufficient pressure in the line 219 to dispose the pistons 205 remotely from the inner ends of their cylinders to yieldingly constrain the links 167 to assume positions with their heads in relatively closed positions rather than in open positions. That is, the heads are constrained to face more inwardly toward a central point, rather than face forwardly.
If it is assumed that the heads engage a roll of large diameter, larger than the diameter of the are along which the heads are disposed, the outer heads 37 and 43 will be first engaged and shoved rearwardly thus pivoting the mounting links 167 to swing the inner heads 39 and 41 forwardly for proper engagement with the roll. This pivoting movement of the links 167 will move the pistons 205 inwardly, as the parts are shown in FIG. 26. Fluid is prevented by the check valves 215 from flowing from the pistons directly into the line 219, but check valves 217 permit the fluid to flow into the line 223 from whence it floyv s through the valve 225 and line 227 to line 219 and thence to the accumulator 221.
Assuming that the valve 55 (FIG. 1) is open so that the suction heads are connected to the vacuum pump 51, a drop in pressure will occur at the heads soon after they contact a load. This drop will shortly be suflicient to actuate the vacuum switch 231 (FIG. 26) to close valve 225. Thus, further opening movement of the heads is prohibited. The reason for locking the heads against opening movement is to hold the heads firmly in place to support the roll when the apron 35 is rotated to a position with the roll axis horizontal, or if the roll is already horizontal, to enable the heads to support the roll when the carriage is lifted.
It is pointed out, however, that even after the valve 225 has closed, links 167 may pivot in directions to further close the heads, such as for instance, when a small roll is being lifted and the vacuum switch 231 has been operated prior to the time the heads have conformed to the contour of the roll. This movement of the links 167 may take place because fluid can flow from the accumulator 221, through line 219, through check valves 215 into the inner ends of the cylinders. Such fluid flow enables the mentioned movement of the links 167.
Overall Suction System Referring to FIG. l'the suction hose 53 leads from the truck over the sheave 57 and down to a tube 251 (FIG. 6) mounted by a support strip 255, on the cylinders 141. The tube 251 extends through a bore in the pinion gear 143 and has a rotary sliding fit in the leg of the suction T 233. An O-ring 257 provides a seal between these parts.
The suction T 233 is secured by a mounting strip 261 (FIGS. 4 and 7) to the revolving apron 35, and the arms of the T are connected by hoses 263 and 265, as shown in FIGS. 4 and 16, to the legs of a pair of T valves 267 and 269 disposed above and below the apron respectively.
As shown in FIGS. 5 and 16, hoses 270 connect the arms of the valves 267 and 269 to the inner arms of suction Ts 271, the legs of which are secured to the base plates 161 (FIG. 11) of the inner suction heads. Hoses 273 (FIG. 16) connect the remaining arms of the Ts 271 to nipples 275 on the base plates 161 (FIG. 5) of the outer suction heads.
Suction Head Construction Referring to FIGS. 10 through 15, each suction head is provided with an elastomer sealing member 281 of open rectangular form (FIG. 10) secured by strips 282 (FIG. 11) to the edges of the base plate 161. The sealing member is molded on its inner surface with a groove 283 to receive the edge of the base plate 161. Thus, there is a lip 285 at the back of the base plate, and a lip 287 is at the front. The lip 287 is hollow and thus has an outer Wall portion and an inner wall portion. The inner wall portion is thickened near the plate 161 whereas the outer wall portion is not thickened at such place. The thickened portion projects inwardly to constrain the lip 287, when in engagement with a load, to flex outwardly rather than inwardly. The lip 287 may be provided with vents 288 to enable it to deflect more readily.
Two dams 291 form part of and extend between the sides of the sealing member, and engage the load and separate the head into three suction sections.
Each base plate 161 is provided on its rear face with an airtight manifold member 301 of angular form secured at its ends to the adjacent clevis members 163. The manifold member communicates with ports 303, 305 and 307 formed in the base plate 161 along the length thereof, so that the three suction sections of the head are in communication with one another.
On the front of the base plate 161 are three flexible roll engaging plates 311, 313 and 315 of rectangular shape. Each plate comprises a metal sheet 317 having an elastomer sheet 319 bonded to the front face thereof. The elastomer sheet 3 19 has a front face of generally wafile form for proper communication of the various parts of the face plate with the source of vacuum. Each plate is provided with a plurality of air ports 321, three being shown.
Suction Plate Mounting Each plate is mounted in the same manner, and the mounting arrangement comprises two pairs of rocker elements 333 (FIGS. 11 and 15) of half round cross section secured to the plate by screws 335. The elements of each pair are in longitudinal alignment with one another and in spaced endwise relation. The round portions of the rocker elements are designed to bear against the front of the base plates 161.
The rockers are held in contiguous relation to the base plate by a T-shaped retainer having a threaded shank 337 (FIG. 14) passing through the base plate and secured by a nut 339 to such plate. The head 341 of the retainer is formed with a through oversize bore 343 loosely receiving a pin 345, the ends of which have a drive fit in the adjacent ends of the associated rocker elements. The head 341 has a peaked front surface 347 (FIG. 13) to facilitate flexing of the associated plate without interference by the head.
The oversize bores 343 not only facilitate contact between the rocker elements 333 and the base plate, but also facilitate slight lateral movement of the rocker elements which is necessary when the flexible plate flexes, as can be appreciated by examining FIG. 15.
Automatic Suction Valves Referring to FIGS. 19 and 20, the arm portions 269' and 269" of the valve 269 are each provided interiorly with a valve seat 361 and a movable valve element 363 for each seat. A rod 365 secures the valve elements to one another in the desired spaced relationship. The valve elements and the rods may be considered as a valve unit. A light compression spring 367 engages a scalloped flange 369 of each valve element and disposes the valve unit in a centered position with both valve elements spaced from their seats. Each valve element has a small passage or orifice 371 formed therethrough.
While the overall operation of the roll pick-up device will be given shortly, the operation of the above valve will be given here.
If it is assumed that the pick-up device is ap roaching a roll, the springs 367 will hold the valve unit in it centered position whether or not the control valve 55 isolates or connects the leg 269" of the valve to the vacuum pump. If a suction head to which the arm 269" is connected engages a load (FIG. 21) the pressure in the right-hand end of the arm will drop substantially below atmospheric pressure. If the suction head to which the left-hand arm 269 is connected is not against the load or a load, the pressure in the left-hand arm will remain substantially atmospheric. This difference in pressure acts on the valve unit to force it to the right to seat the left-hand valve element 363 (FIG. 21) and further unseat the right-hand valve element 363. This substantially decreases the loss of vacuum, and facilitates the use of a smaller capacity vacuum pump than Would otherwise be the case. More importantly, the valve permits the device to pick up a load which covers only part of the area of the overall} suction means, by automatically closing off any vacuum head not covered by an article to be lifted.
Should the head to which the left-hand arm 269' is connected subsequently engage the load or a load, the air in the left-hand end of the arm will be drawn through the passage 371 to drop the pressure in such end. This drop in pressure lessens the differential pressure across the valve unit, so that the centering springs 367 can again center the valve unit so that both valve elements are unseated. This provides for open communication between the suction heads and the vacuum pump.
FIGS. 22 through 25 show a modified form of automatic valve for attachment to a single head. The tubular body 381 has a shoulder 383 providing a valve seat against which a valve element 385 may seat. A single compression spring 386 bears against a scalloped flange 387 on the valve element, and a snap ring 389 limits movement of the valve element to the left. The valve element is formed with a through small passage or orifice 391.
If it is assumed that the right-hand end of the body 381 is connected to a source of vacuum, and the left-hand end to a suction head, the spring will dispose the valve ele ment in an open position when the vacuum is off. When the vacuum is on as in FIG. 23 a differential pressure across the valve element is created, so that the valve element closes against the seat.
Now, if the suction head which is connected to the left-hand end of the valve body is disposed against a load, there will be a pressure drop in the left-hand end of the body because of the passage 391, to thereby lessen the differential pressure across the valve element sufliciently to enable the spring to open or unseat the valve element for better communication of the suction head with the pump.
OVERALL OPERATION Let it be assumed that the roll to be picked up is in a vertical position as shown in FIGS. 1 and 2, and that it is of substantial diameter, that is having a diameter such that it will first engage the outer heads 37 and 43. The operator will drive the truck up to the roll, attempting to center the truck on the roll. However, exact centering is not required since the base member 33 can pivot about the connection 34 to center the heads with respect to the roll.
Prior to or at about the time the heads engage the roll, the operator opens the valve 55, and suction i available at the heads because the apron valves 267 and 269 (FIG. 19) are open (there being as yet no differential pressure across the valve units of the valves).
Contact of the heads with the roll will swing and pivot the heads to positions conforming the positions of the heads to the curvature of the roll, bodily swinging movement of heads being permitted by the open valve 225 (FIG. 26).
The contact between the heads and the roll shortly creates a pressure drop at the heads and at the vacuum switch 231 to lock the heads against further opening movement. Normally, the locking of the heads occurs after the heads have fully conformed to the contour of the roll.
Although the outer heads 37 and 43 first contact the roll, this will not atfect the apron valves 267 and 269 because, by reference to FIG. 16, it is apparent that there is still no differential pressure across the apron valves.
As the pressure at the heads continues to drop, the atmospheric pressure on the opposite side of the roll forces the heads and roll together with suflicient pressure of contact to deflect the head plates 311, 313 and 315 into conforming relationship to the roll, as shown in the case of plate 311 in FIG. 27 and with suflicient pressure to enable the roll to be lifted. Also, the sealing member 281 is deformed outwardly to create a good seal with the roll.
Paper such as newsprint or kraft paper or the like is permeable to the passage of air therethrough, at least to a limited extent. Thus the creation of a subatrnospheric pressure on a selected area of the cylindrcial surface of the roll will create a pressure gradient over the area, wherein the pressure is lowest on the outer surface of the outermost convolutions and increases in magnitude toward the center of the roll through successive convolutions. After the pressure gradient is created, the zone of subatmospheric pressure at this area may be moved to impart movement to the plurality of layers because of the pressure gradient and to impart movement to the remaining layers because of their enclosure by the just-mentioned plurality of layers.
Now, the roll may be picked up by elevating the load carriage, and the roll may be rotated to the horizontal position if desired for proper disposition for use or storage. In such horizontal position, the pins 345 and the retainers 337, 341 support the head plates 311, 313
and 315 against downward shifting movement. It is pointed out that the pressure of contact between the roll and head plates must be suflicient to create a frictional force between the roll and the head plates greater than the weight of the roll. However, the roll is not picked up because of adherence of the suction heads to the outer loop of paper on the roll, but because the roll is being pressed against the heads by the differential pressure across the roll created by the suction heads. Thus, by reference to FIG. 28, a roll having an unattached outer loop L may be picked up, providing the outer loop is pressed tightly against the remainder of the roll prior to the suction heads being connected to the vacuum pump.
Referring to FIG. 3, a roll in a hozontal position may be picked up by rotating the apron to dispose the heads as shown and locating carriage so that the lower pair of heads, 37 and 39, is at the approximate center of the roll. When the truck is now further advanced toward the roll, heads 37 and 39 contact the roll at which point, the operator lowers the apron while still advancing the truck. The frictional force between the heads 37 and 39 impart a counterclockwise rotation to the roll (as viewed in FIG. 3) which compensates for the usual tendency of the roll for rolling away from the truck. It is understood that, at this juncture, the vacuum has not yet been applied. To compensate for operator errors, the attachment can pivot slightly around pin 109 (FIG. 8) as controlled by springs 119.
Instead of lifting a large roll, two small rolls may be lifted by the suction heads, or a single small roll may be lifted by one pair of heads, such as for instance, heads 37 and 39. Under the latter circumstance, the heads 41 .and 43 will be open to the atmosphere. Referring to FIG. 16, it is apparent that a lower pressure will exist in the suction lines to the left of the apron valves 267 and 269 than in the lines to the right. The differential pressure across the valve unit of each valve (FIG. 19) will cause a shifting of the valve units to the left to close off communication of the heads 41 and 43 with the vacuum pump.
Instead of a roll, a fiat faced package could also be readily picked up, with the heads pivoting to the proper positions for flush contact.
MODIFIED FORMS FIG. 17 shows the suction heads connected by a modified manifold system, which facilitates cutting off vacuum to various suchtion sections of the head to facilitate lifting a short roll, or a short load or package, in the event the heads lie in a common plane, or if there is only one suction head divided into twelve suction sections (or other even number of sections).
There is a central apron valve 401 between the valves 267a and 260a. A left apron valve 403 is connected by a line 405 to the central apron valve 267a and by lines 407 to suction sections 37a and 39a, and by lines 409 to suction sections 37b and 3%.
There is a right-hand apron valve 411 conected by a line 412 to the central apron valve 269a and by lines 413 to suction sections 41b and 43b and by lines 415 to suction sections 410 and 43c. A line 417 connects apron valve 269:: to suction sections 370 and 39a, and a line 41? connects apron valve 269a to suction sections 41a and 43a. As a side note, the dams 291 (FIG. 11) isolate the suction sections from one another, and no rear manifolds such as 301 are employed in the FIG. 17 construction.
Let it be assumed that a load contacts the b and c sections but does not fully contact the a sections. A differential pressure is created across valve 403 to close lines 407 and isolate 37a and 39a from the source of vacuum. This situation also means that there will be a differential pressure across valve 267a to close off line 419 and heads 41a and 43a from the source of vacuum.
10 There will be low pressure on both sides of apron valve 401 so it remains open to both of its lines. Thus, only the suction sections in contact with the load are connected to the source of vacuum.
Assume, now, that the load contacts only the 37 and 39 sections. The valves 267a and 26% function to cut off vacuum from the 41 and 43 sections. Suppose the load contacts only sections 37b, 39b, 37c and 39c. Valve 269a will cut off sections 41b, 43b, 41c and 430. Valve 403 will cut off sections 37a and 39a, and valve 267a will cut off sections 4111 and 43a. Thus only the sections which fully contact the load are supplied with suction.
Now suppose only sections 370 and 39c contact the load. Valve 269a will cut off sections 41b, 41c, 43b and 430. There will be no pressure differential across the valve 267a because its sections are all open to the atmosphere. However, there will be a differential across valve 401, which will act to close off all the sections associated with valve 267a. Thus, again, only the sections fully contacting the load are supplied with suction.
Referring to FIG. 18, the suction sections of the heads 437 and 439 each has a valve 381 of the type shown in FIG. 22. Thus, only the sections that are fully contacted will be supplied with suction. A difference between the FIG. 17 and the FIG. 18 arrangements, is that if only a single section in FIG. 17 fully engages the load, suction will also be supplied to its companion section, while in FIG. 18 only the section engaging the load would be supplied with suction.
Having described the invention in what is considered to be the preferred embodiment thereof, it is desired that it be understood that the invention is not to be limited other than by the provisions of the following claims.
1. A suction head comprising a base member, a sealing member on said member defining at least one encircled area, a plate-like load engaging member separate from said sealing member and disposed within said area and mounted on said base member, said member being flexible to tend to conform to the shape of the load engaged, said member being of a size to substantially fill said area.
2. In a suction type load pick-up device,
a plurality of suction elements for engaging a load,
a source of vacuum for said elements,
a separate valve means between each element and said source,
each valve means including a housing and a movable valve element in said housing movable toward and away from a seat in said housing, each valve member having a seating surface facing the associated seat,
each valve member being slidably supported in its housing for rectilinear movement toward and away from said seat, to maintain said seating surface facing said seat, each valve member having a shoulder, and a compression spring for each valve member, each spring being disposed between the shoulder of its valve member and an opposed portion of its housing and urging its valve member away from its seat,
each valve member being operable to seat against its seat in response to the influence of a predetermined differential pressure thereacross,
each valve member being formed so as to provide substantial air passages between itself and said housing for ready passage of fluid therepast,
each valve member having a leakage passage formed therethrough so that a suction may be created on the side of said valve member remote from the source of vacuum despite the valve member being closed.
3. In a suction type load pick up device,
at least two suction heads,
a common valve for controlling the communication of said heads with a source of vacuum,
said valve having two seats, one for each head,
said valve having a valve member engageable with one seat when said member is moved to one position and engageable with the other seat when moved to another position and engageable with neither seat when 5 in an intermediate position,
and means urging said valve member to assume its intermediate position but being sufficiently sensitive to allow said valve member to shift under the influence of differential air pressure thereacross, said 10 member being so located relative to said heads and said source that when one head only engages a load, a dilferential pressure will be created across said valve member to shift it in a direction to close off communication of the other head with the source of 15 vacuum.
References Cited in the file of this patent UNITED STATES PATENTS Hitchcock Feb. 11, 1919 Debaecker Aug. 19, 1924 Lente Apr. 25, 1944 Billner Dec. 11, 1951 Frischmann et al May 13, 1952 Frischmann July 22, 1952 Sherrifl July 13, 1954 Littell June 9, 1959 Cushman July 7, 1959 Corbin Aug. 11, 1959 Morris et al. Sept. 8, 1959 Cotesworth et al Dec. 1, 1959 Horton June 28, 1960 Leighton Nov. 28, 1961