US 3823438 A
Apparatus for cleaning the inner surfaces of mouth portions of sacks prior to closure, e.g., by heat sealing, has suction means to engage the two lips of the mouth portion to part them, and a finger having suction cleaning means on opposite sides which is inserted between the parted lips. The finger and sack are then relatively traversed so that the finger scans a band along each of the said inner surfaces. The means to part the lips may be vacuum heads and there may be a bellows-construction in the vacuum linkage which contracts when the head is applied to the mouth portion, thereby withdrawing the head and causing the lips to part.
Claims available in
Description (OCR text may contain errors)
United States Patent [191 Webber et al. [451 July 16, 1974  APPARATUS FOR HANDLING SACKS v  inventors: Geoffrey Terence Webber; James pmflary Examirfer'fiarvey Hornsby Henry Winchester Thorne, both of 4 Exammer"? Bristol, England Attorney, Agent, or Firm-Omn M. Behr  Assignee: Whitehall Machinery Limited Bristol, England  ABSTRACT Apparatus for cleaning the inner surfaces of mouth  Flled' 1972 portions of sacks prior to closure, e.g'., by heat sealing, ] Appl. No.: 223,248 has suction means to engage the two lips of the mouth portion to part them, and a finger having suction cleaning means on opposite sides which is inserted bel5/304,A1:4i3g?3la tween the parted Pa The finger and sack are then Fi d 6 B 303 relatively traversed so that the finger scans a band e o a 53/167 along each of the said inner surfaces. The means to part the lips may be vacuum heads and there may be a  R t Ct d bellows-construction in the vacuum linkage which 1 e erenceis I e contracts when the head is applied to the mouth por- UNITED STATES PATENTS tion, thereby withdrawing the head and causing the 3,432,982 3/1969 Brinkmeier et a1. 53/167 X lips to part. 3,488,910 1/1970 Stoger et a] 53/167 X 3,505,136 4/1970 Attwood 53/167 x 3 Claims, 5 Drawlng Figures PATENIE JUL 1 61974 SHEET l- UF 4 I I 1 APPARATUS FOR HANDLING SACKS This invention relates to apparatus and method for preparing sacks for heat-sealing, particularly sacks of which at least mouth portions are made up of, or lined with, heat-sealable material and which are intended to n be closed by heat-sealing.
One problem which arises in the closure of sacks in automatic manner is that of ensuring that the surfaces which are closed together are adequately clean. This is particularly serious when heat-sealing is to be used as the means of closure since dust or granules between the introducing the finger between the lips so opened and means for causing relative movement of the finger and the sack so that the finger scans a band along each of the mutually inner surfaces of the mouth portion of the sack, the finger having on opposite sides suctioncleaning means for removing particles from these bands.
The means for parting the lips may be one or more vacuum suction heads, preferably one to each side of the sack, and may include a bellows-construction linkage for at'least one of the said heads such that when the vacuum isapplied between the head and the material of the sack the bellows contracts thereby withdrawing the head with the material attracted to it. The finger may be inserted into the sack mouth by rotational movement and may then remain stationary while the sack is caused to execute longitudinal movement past it, the finger being caused to execute further rotational movement for, retraction from the mouth by abutment with an end wallof the mouth of the sack. Movement 'of the finger may cause opening and closure of valves concerned with the supply of vacuum to vacuum heads used in drawing apart the lips of the sack. The finger may attract the-material of the sack at the mouth portion to itself by being provided with a vacuum port or ports, and acting at the same time to draw the particles off the material. The finger may be provided additionally with a mechanical scraper to act on the surface of the band of themouth portion, the portion being held in abutment with it. The finger may be a composite finger, that is to say, may comprise two or more elements to act respectively on the said surfaces on different sides of the sack mouth.
A particular embodiment of the invention will now be described with reference to the accompanying drawings, wherein:
FIG. 1 shows in diagrammatic plan view, apparatus for cleaning the mouth of sacks;
FIG. 2 shows in end view, looking in the direction of travel of a sack, part of the apparatus of FIG. 1 the lips of a sack mouth being closed;'
FIG. 3 is the same view as shown in FIG. 2 but the lips of the sack mouth are drawn apart and the chains 17 are engaging the sack,
- FIG. 4 is a sectional view taken at right angles to FIG.
2 of partof the apparatus of FIG. 1 along the line 4-4 2 in FIG. 1, showing a cleaning finger immediately after descending into the mouth of the sack,and
FIG. 5 is the same view as FIG. 4, but shows the finger at the end of its action on the sack.
In FIGS. 2 and 3 a sack 1 is travelling into or out of the plane of the paper. The path of a sack is shown by arrow A in FIG. 1. The sack'l has been filled and is in transit to a heat sealing machine 20 (FIGS. 1, 4 and 5). It is supported below by a conveyor (not shown) which transports it through the mouth cleaning apparatus and on to the heat sealing machine. The sack is made entirely of plastics material of a heat-scalable nature. Its mouth portion is shown at 1a. The lips 8 of the mouth portion can be drawn apart but at each end of the sack (loading and trailing in the direction of travel) there are end walls 11, 12 which link the two lips. In the case of the gusseted sack, the end walls will be infolded in The neck 16 of a sack 1 below the mouth portion 1a is gripped between two carrier chains 17, one on each side, as it approaches the guideway 4b. The chains maintain the position of the neck during the mouth cleaning operation.
In operation vacuum is applied as described below to the vacuum heads 2 as the sack approaches and when the sack is between them the two cups 3 each draw the material of one lip of the sack towards themselves. When the leading edge of the sack has passed beyond the cups 3, this causes a partial or complete obstruction of gas entry to each cup from the atmosphere so that reduced pressure is applied inside each bellows 7 which therefore contracts and moves the cups 3 axially towards the fixed duct 6. This condition is shown in FIG. 3 which shows also that this axial movement causes tilting of the cup and of the: plate shown at positions 3', 4, so that the lips 8 are drawnapart. This enables a cleaning finger 9 to be inserted between them.
FIG. 4 shows a side view taken in a direction at rightangles to FIGS. 2 and 3 at a time: when the lips 8 are being held apart (some parts are omitted for clarity).
A finger 9 is mounted on a sleeve 10 which rotates about a tube 10a forming a pivot positioned above the level of the heads 2, and lying perpendicular to the direction of travel of a sack. The finger 9 is driven by a double acting air-operated cylinder 18, the piston rod 39 of which is pivoted to a rod 10b mounted on the tube so that operation of the cylinder rotates the finger 9 about the tube 10a as described below. Rotational movement of the finger 9 into the sack in the sense of the arrow B from its initial position shown in FIG. 4 in dotted lines to the position shown in full lines, wherein it is vertical, is effected by the cylinder 18 when the sack mouth 1a has been opened as described above. This rotational driven movement is a swift movement so that the finger overtakes the sack as this is moved by conveyor means, not shown, in the sense of the arrow A. When the finger adopts the full I ues until the finger is lifted'clear of the sack i.e.,
reaches the position shown in broken lines in FIG. 5, after which it is returned by the return action of the spring 9a to the dotted. line position shown in FIG. 4.
The initial rotation of the finger causes overtaking of the sack in order that the finger will be brought right into the fold of the leading wall 11 of the mouth portion.
The tube 10a is adapted to act as a valve to control the admission and release of vacuum to the vacuum heads 2. Ports in the tube 100 register with ports in the sleeve 10 to supply vacuum to the finger 9 when the finger is in the vertical position of FIG. 3, and further ports are in register to supply vacuum through the lines 6 to the heads 2-when the finger 9 is in the dotted line position of FIG. 4, these latter ports being brought out of register cutting off vaccum to the heads 2 when the finger has adopted its vertical position. The vacuum is supplied through a pipe 21 to the tube 10a and passes to the bellows 7 through pipes 6. When the finger 9 comes back to the dotted line position of FIG. 4, the vacuum line 21 is again connected to the heads 2 in readiness for the next sack 1 (FIG. This arrangement ensures opening of the lips 8 by the vacuum heads 2 when a sack passes between the heads 2 and then release of the lips when the finger 9 is rotated to its vertical position between them. As mentioned above also, vacuum is introduced through ports in the tube 10a and sleeve 10 to ducting contained in the finger 9 and connected to ports 14 in its sides towards its outer end. Ports 14 are provided on both sides of the finger, each set of ports being designed to remove particles, e.g., particles of the material with which the sack is filled, by vacuum suction from a band on each of the two mutually inner surfaces of the mouth portion which is swept by those ports and which is indicated at 15 in FIG. 5. The vacuum applied to the ports 14 tends to draw the material of the sack towards the finger 9.
The operation of the cylinder 18 to rotate the finger 9 into the vertical position is controlled through a solenoid valve 19 by a microswitch 22 which has a feeler arm 23 pivoted at 24 and engaging a switch button 25. The end 26 of the feeler arm 23 is in the path of the sack. When the leading end of a sack passing through the apparatus engages the feeler arm 23, the button 25 is pressed and the microswitch emits a signal which causes the solenoid valve 19 to admit compressed air from the mains inlet 27 into the cylinder 18 so as to rotate the finger to its vertical position (FIG. 4). This causes cutting off of the vacuum to the heads 2 as described above. When the sack has passed the feeler 23,
the microswitch emits another signal which causes reversal of the cylinder 18 to its initial position.
A finger in apparatus embodying the invention may be composite, being made up of two or more elements disposed laterally of each other, means for cleaning being on the mutually outer surfaces. This form of finger is particularly useful for a gusset folded sack, since the elements can enter into double fold forming the end of the mouth. portion of such a sack.
In a embodiment of the invention alternative to that shown in the drawings, a straight line (usually vertical) insertion motion might be used'(witliout rotation) to insert the finger into the sack, the finger then being i held stationary, or moved counter to the movement of the sack, and then beingretra'cted in a straight line, e.g., vertically. The movements of the finger may again in this case mechanically control the application or release of vacuum. But in either case electrical contact may be made, through solenoid-operated valves.
Further, cleaning means on the finger need not be only vacuum elements but could include brushing,
scraping or wiping elements, and in this case it would be desirable to provide for counter-pressure on the outside of the sack to press material of its mouth portion onto such elements. This might be by means of a roller or leaf spring. With some products with which the sack has been filled, satisfactory cleaning can be obtained using a jet of compressed air from the finger as well as the vacuum suction. The cleaning finger could have a separate channel for the supply of compressed air to remove loose dust first in addition to a channel for the vacuum supply to remove remaining dust.
Means for pulling apart the lip portions 8 may move with the sack; otherwise plates 4 may take the form of slide plates past which the sack moves since the drawing apart and consequent contact of the material of the sack on those plates need last only for a sufficient period to allow the introduction of the finger.
As a result of the relative movement of the finger and the sack a band 15 is cleaned of particulate material and the sack is then passed to a closure machine which closes it along that band. In normal circumstances the present apparatus will have been installed because that closure will be made by the heat-sealing either of a heat-sealable adhesive applied to a non-heat-sealable sack material or of the material itself of the sack mouth portions.
It will be desirable to ensure regularity of the position of operation of the finger so that the clean band 15 is an ascertained position in the sack and for this purpose levelling guides will preferably be provided on the conveyor mechanism or the feeding of the sack to that mechanism will be at a controlled level.
What we claim is:
1. Apparatus for preparing mouth portions of sacks for closure which includes suction means for opening lips of the mouth portion of a sack, a cleaning finger, means for introducing the finger between the lips so opened and means for causing relative movement of the finger and the sack so that the finger scans a band along each of the mutually inner surfaces of the mouth portion of the sack, the finger having an opposite sides suction-cleaning means for removing particles from these bands.
2. Apparatus according to claim 1 wherein said suction means for opening the lips comprises at least one vacuum suction head.
3. Apparatus according to claim 2 wherein for the said at least one suction head there is a bellowsconstruction linkage such that when the vacuum is applied between the head and the material of the sack the bellows contracts thereby withdrawing the head with the material attracted to it.
4. Apparatus according to claim 2 wherein at least one such vacuum suction head is provided on both lateral sides of the said mouth.
5. Apparatus according to claim 2 wherein movement of the finger from an inoperative to an operative 6 sack is caused to execute longitudinal movement past it, and then being retracted from the mouth of the sack by rotational movement, this retracting movement being caused by abutment of the said finger with an end wall of the mouth.
8. Apparatus according to claim 1 wherein movement of the finger from an inoperative to an operative position causes supply of vacuum to the suctioncleaning means on the finger.