US 3313568 A
Description (OCR text may contain errors)
A ril 11, 1967 D. A. FOGG HEAD FOR PALLETIZER 2 Sheets-Sheet 1 Filed Oct. 21, 1965 INVENTOR. fi4/V/EZ ,4 F066 Q1! 77 A ril 11, 1967 D. A. FOGG HEAD FOR PALLETIZER 2 Sheets-Sheet 2 Filed 001:. 21, 1965 @H. I I
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ilnite States atenr @mce 3,3l3,5h8 Patented Apr. ll, 1967 3,313,568 HEAD FOR PALLETIZER Daniel A. Fogg, White Cloud, Mich, assiguor to The Rapids-Standard Company, Inc., Grand Rapids, Mich, a corporation of Michigan Filed Oct. 21, 1965, Ser. No. 499,988 6 Claims. (Cl. 29464) This invention relates to pressure differential hoisting apparatus, and more particularly to a negative pressure hoist apparatus for lifting and transferring a plurality of items such as cartons.
Vacuum type lift heads have been employed heretofore for hoisting and transferring a plurality of items such as cartons. These units have a vacuum head which evacuates the area above a pattern of carton tops to cause atmospheric pressure on the carton bottoms to retain the cartons up against the head as it is moved.
One of the basic operational problems encountered with known lift devices is that of obtaining a tight seal of the head to the cartons to effect a sufiicient vacuum for lifting the cartons without accidentally releasing one or more of them prematurely. Efforts made to improve the seal and increase the lifting force include the attachment to the head of a peripheral depending wall to engage the outer periphery of the cartons for increasing the lateral squeezing effect on the cartons, and the use of a resilient peripheral cushion to contact the upper outer edges of the cartons for better sealing. While these frequently do improve the hoisting dependability of the apparatus, they still involve the possibility of seal failure against the cartons, particularly if one or more cartons is spaced inwardly significantly from the flaps or cushions. The peripheral wall type for example might not engage the carton side walls during evacuation, so that an air stream flows between the wall and the cartons to prevent effective head evacuation. The resilient cushion type can allow air leakage if not centered properly on the cartons, and further provides little if any lateral squeezing force on the cartons. Hence, with both of these types of devices, the specific overall dimensions of the group or pattern of cartons or other items must be carefully controlled in order to properly interfit with the surrounding member. If they are not of a closely interfitting size, the proper sealing or gripping action will not occur. In the absence of this, these known types of heads cannot hoist the cartons.
It is an object of this invention to provide a novel negative pressure lifting head for hoisting items such as cartons, with the head having excellent capacity for forming an immediate and effective seal against the items when the head is engaged on the items. It also etfectuates an excellent lateral squeezing action to assure good hoisting action on the items as a unit.
Another object of this invention is to provide a lifting head of the negative pressure type, having lateral squeezing effect and peripheral sealing action against the cartons, but also allowing a substantial variation in the dimensions of the group pattern of articles to be hoisted.
Another object of this invention is to provide a lifting head having a unique flexible sack or bag to achieve assured sealing contact with the periphery of the cartons, whether or not the carton group varies in its dimensions.
Another object of this invention is to provide a lifting head having a novel flexible sack in combination with special peripheral flap means, the two being cooperative to eifect an immediate seal and also assuring excellent physical engagement and lateral squeezing of the flap means with the cartons to obtain optimiun hoisting action.
These and other objects of this invention will become apparent upon studying the following specification in conjunction with the drawings in which:
FIG. 1 is a plan, somewhat diagrammatic view of the novel device and a pattern of cartons to be hoisted onto an exemplary pallet;
FIG. 2 is a side elevational view of the device in PEG. 1 taken on plane Il-ll;
FIG. 3 is a side elevational view similar to that in FIG. 2, showing the device in use as a hoist;
PEG. 4 is a sectional elevational view of a modified form of the apparatus; and
FIG. 5 is a fragmentary enlarged elevational view of a portion of the apparatus in FIG. 4 interfitting with a carton.
Referring now to the first form of the invention illustrated in FIGS. 1 through 3, the negative pressure hoist apparatus ll) basically includes a platen 12, a blower 14, a motor 16 operating the blower, a carton-engaging under surface on platen 12, preferably including an undulated surface area 18 as of chain mail stock (i.e., interconnected links in a sheet), a peripherally attached and sealed depending fiexible sack 2%, and preferably a plurality of depending gripping edge flaps 22a, 22b, 22c, and 22d inside the sack and around the periphery of the platen adjacent the edges thereof.
Platen 12 may be of any suitable support material capable of hoisting a plurality of cartons of the type encountered. It can be made of wood, metal, or other selected structural material. It is generally nonporous having only opening means to the blower. Its size and configuration may be modified to suit the particular use. Normally, it is generally rectangular or square in configuration as shown. The platen may be hoisted by any suitable means of the many conventionally employed. For example, it can be hoisted by attaching elevating tension lines to a plurality of spaced lifting eyes 26 secured to the upper surface of the platen.
Evacuation means may be mounted directly on the platen as illustrated, or may be mounted on a separate support and operatively in communication with the platen through a flexible hose. It is here shown as a single blower 14 of centrifugal type, having its central inlet in communication with opening means 3%) extending to the underside of platen 12, and its tangential outlet 32 discharging to the atmosphere. its outlet is controlled between open and closed position by a butterfly valve 34 operated through a suitable actuator 35 such as a manual handle or a powered equivalent. This valve pivots on its central transverse horizontal shaft 38, the ends of which are mounted to the outlet housing. The blower is operated by a suitable power means such as electrical motor 16.
The novel components of the apparatus are the sack type member 20 and the plurality of pivotally mounted independent planar depending flaps cooperating with the previously described components.
More specifically, sack 20 is of a highly flexible, sealing, impervious material, preferably of a polymeric type. Originally, experimentation was conducted with heavy plastic film such as polyvinyl chloride of several thousandths inch thickness. Subsequently, it was determined that a thicker rubber base material such as neoprene served even better, with this neoprene being up to about of an inch or so thickness. This sack depends beneath the platen periphery, and extends across the underside of the platen so as to basically encompass it except for a central opening 39 generally in communication with suction opening 30 through the platen. This sack has its peripheral edge secured and sealed to the periphery of platen 12 as by tacking, adhesive, or any other suitable method. The sack extends from each edge down around the respective flaps 22a through 22d, and across the under surface of the platen with sufficient slack to extend up against the platen under surface during operation as shown in FIG. 2. Frequently, depending upon the thickness and flexibility of the material employed, it hangs beneath the flaps in the manner indicated by phantom line 20'. It is important that this sack extend across the under surface in order to effectuate the sealing action engagement with the cartons as explained more fully hereinafter. Since the sack does extend across the under surface, it must include opening means such as the central opening 39 so that the blower can evacuate the air immediately above the tops of cartons engaged.
The under surface of platen 12 has an undulated under surface which may be integral or formed with an attached layer. The undulating means 18 is here shown as a separate element. It has been found by experimentation that a conventional chain mail sheet or layer achieves excellent operating characteristics. The undulation feature is significant because, when space 21 inside the envelope or sack 20 is evacuated, and the flexible sack is pulled up into tight sealing engagement with undulated surface 18, air flow passage means is still maintained both (1) above this member and (2) beneath the flexible sack adjacent the carton upper surfaces. This latter passage means is achieved because the rubber or plastic sheet is drawn up into the openings between the wire members of the undulated element so that the under surface of the sheet itself becomes undulated, resulting in continuous passages between it and the flat upper surface of the carton.
In the preferred form of the invention illustrated in FIGS. 1 through 3, the flexible sack is in combination with a plurality of flap members 22a through 22d pivotally mounted on their upper edges as by hinges 50 to the under surface of platen 12. Each planar flap is therefore free to pivot toward and away from the peripheral face of the group of cartons. The flaps are generally sernirigid to provide some lifting action, but have limited flexibility to flex slightly against the carton side faces as shown in FIG. 3. Each flap is independent of the remaining flaps on the structure. The number of flaps employed will depend upon the number of edges of the pattern of cartons to be hoisted. These flaps effectuate a lateral squeezing and gripping action on the cartons. Their action is aided by the sack, particularly during initial evacuation. T he dimension of the pattern of articles to be hoisted can actually vary considerably from the spacing between these flaps, since the flaps are pulled into operative relation to the carton by the action of flexible sack 20.
More specifically, referring to FIGS. 1 and 3, if a group of cartons in a pattern P is to be shifted from the position on the right illustrated in FIG. 1 onto a pallet Pa by hoist mechanism 10, the hoist, with valve 34 closed, is moved over the top of the cartons and then lowered so the cartons contact and press against flexible sheet 20 of the sack. The hoist head is lowered until the cartons force the flexible sheet up against undulated member 18. Then, valve 34 on the blower is opened (as illustrated in FIG. 4) so that air is evacuated from the space above the cartons and below platen 12 and through outlet 32. This evacuation initially causes evacuation of the space 21 between the flexible sack and the platen. As this space is evacuated, the outer portions of the sack on the outside of the flaps draw toward the cartons and push the flaps into operative engagement with the adjacent sack portions and against the carton peripheries as illustrated in FIG. 4. It has been found that even if the overall dimension of the pattern of the cartons is substantially smaller than the spacing between the flaps, this shifting action by the flexible bag will achieve proper engagement of the flaps against the sides of the cartons to provide an effective gripping and squeezing action.
The sack not only serves this function of shifting the flaps into operative engagement, but also serves to form an excellent seal against the outer peripheral portions of the cartons because it overlaps the inner faces of the flaps as well as the outer faces. This is particularly helpful, for example, where hand hold openings are contained by the cartons, e.g., beer cartons. The flaps of course act to push the inner adjacent depending sack portions against the cartons, with evacuation of this space between the cartons and the sack by passage of the air through the opening means 39.
The space immediately above the surfaces of the cartons remains generally in open communication with opening 39, and thus with evacuation opening 30 because the flexible sheet material of the sack is drawn up into the openings of the links and between the links of undulated chain mail member 18, as shown in FIG. 4. Thus the space between the flat upper surfaces of the cartons and this undulated surface serves to continuously conduct air away and into the blower to maintain the vacuum.
The cartons are thus retained into excellent gripping and sealing relationship with the lifting head, to be hoisted and shifted to the position desired.
The cartons can be released quickly and simply by closing valve 34 to shut off the outlet of the blower. This allows the back pressure and the small amount of leakage into the system to destroy the vacuumsufl'ticiently for the cartons to drop away from the head.
In FIG. 5 is illustrated a modified form of the device that is similar to that illustrated in FIGS. 2 and 3, except that the preferred pivotal flaps are not employed. This device therefore includes as components of the assembly 100 motor 16, blower 14 with its outlet control valve 34, platen 12, flexible sack 20 having its central orifice 39, and undulated member 18, but without the flaps. It has been found that with the use of fairly heavy sack material such as approximately inch neoprene rubber, the flaps can be dispensed with for certain types of loads.
In operation of this device, the hoist is lowered against the cartons so that the main central portion of the sack is pushed up from its suspended state (as illustrated for example at 20') against undulated means 18, while its periphery hangs in a loop against the carton outer walls. Evacuation causes this hanging outer peripheral sack portion to draw tightly around the upper edge periphery of the cartons to achieve an excellent seal for evacuation above the surface of the cartons. The passageway between the planar upper surfaces of the cartons and the rubber sheet is achieved because the sheet is sucked into the openings in the undulated member 18 so as to also be undulated and form a great many interconnecting passages.
With this type of device, experiments have shown that the pattern of cartons or other items can vary tremendously without affecting proper sealing action. It will be realized that even though the carton pattern overall dimensions should vary several inches, the highly flexible sack readily matches the size and configuration of the cartons to accommodate them.
It will be realized that the second form of the device illustrated is less preferred for heavy loads, but has greater adaptability to different dimensional variations in the patterns of cartons. Both devices however are significant in their adaptability to carton patterns of different variations, not being limited to one specific exact dimensional setup.
It is conceivable that certain other details of construction of the two forms of the invention illustrated may be modified within the concepts shown. It is also realized that the two forms of the invention are in ways distinct from each other but have certain characteristics in common. The invention is intended to be limited only by the scope of the appended claims and the reasonable equivalents to those defined therein.
1. A negative pressure hoist comprising: a support platen defining an under surface area for engaging a pattern of articles; peripheral, article gripping and suspending flap means attached to and depending from said platen around said area; a flexible sealing envelope on said platen, across said under surface area, with a first portion along the inside surface of said flap means to seal against articles, and a second portion along the outside surface of said flap means to pull said flap means toward each other for gripping a pattern of articles; said platen including port means into said envelope and adapted for connection to air evacuating means, to. cause the said sealing and flap pulling actions upon withdrawal of air from said envelope; and opening means through said envelope between said flap means for evacuation above the articles.
2. A vacuum hoist comprising: a support platen having a peripheral edge formed of a plurality of adjacent edge portions; a plurality of depending gripper flaps suspended from said platen along said edge portions; a flexible conforming envelope extending across the bottom of said platen and enveloping said flaps; inlet means through said platen to the inside of said envelope to draw the air out of said envelope, causing said envelope to seal against articles adjacent said platen and to pull said flaps against the articles for lateral gripping; and opening means in said envelope adjacent said platen bottom to allow evacuation access to carton tops engaging said bottom.
3. A negative pressure hoist comprising: a lifting platen having an under surface area for engaging a pattern of cartons or like items to be hoisted; a plurality of generally planar carton gripping flaps pivotally attached to and depending from said platen at the peripheral edges of said area; a flexible enclosing envelope sealed to said platen laterally around the outside of said flaps, extending around the bottom edges of said flaps and across said area to peripherally sealingly enclose a carton surrounding space containing said area and flaps; evacuation passage means with the interior of said envelope, whereby, with placement of said platen over a pattern of cartons and said flaps around the pattern, and evacuation of said surrounding space, said envelope will seal around and over the cartons and pull said flaps into gripping relation with the outside walls of the cartons; and opening means through the center of said envelope to evacuate above engaged cartons.
4. The hoist in claim 3 wherein said under surface area includes undulated means, and said envelope being sufliciently flexible to become undulated on said undulated means with evacuation, to maintain air passage means across the upper surface of the cartons for maintenance of the negative pressure differential.
5. A negative pressure hoist comprising: a hoist platen; perforate, item-engaging means on the underside of said platen, forming air passage means adjacent said platen underside; sealing flexible envelope means peripherally sealingly attached to said platen around said perforate means, and depending from said platen, and extending across said perforate means in engageable relation to items adjacent said perforate means; and said envelope means having air passage opening means in the central portions thereof for evacuation adjacent the tops of items adjacent said perforate means, whereby, with lowering of said platform on adjacent items to be hoisted, said envelope means drapes against and around the items, and, upon evacuation thereof, said envelope seals around the items to create a retention pressure differential.
6. The hoist in claim 5 wherein said under surface area includes undulated means, and said envelope being suificiently flexible to become undulated on said undulated means with evacuation, to maintain air passage means across the upper surface of the items for maintenance of the negative pressure differential.
References Cited by the Examiner UNITED STATES PATENTS 7/1958 Pagdin 294 11/1964 Tarbuck 29464 References Cited by the Appiicant UNITED STATES PATENTS GERALD M. FORLENZA, Primary Examiner. G. F. ABRAHAM, Assistant Examiner.