US3882661A

US3882661A - Apparatus for bending the edge of a foil around the edge of a tray

Info

Publication number: US3882661A
Application number: US408111A
Authority: US
Inventors: Eugen Schierle
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-10-27
Filing date: 1973-10-19
Publication date: 1975-05-13
Anticipated expiration: 1992-05-13
Also published as: ATA901473A; FR2204534A1; DE2252927B1; FR2204534B1; ES196937Y; AT334828B; CH556768A; ES196937U; BE806591A; IT995985B; GB1413567A; DE2252927C2; DE2252927A1

Abstract

An apparatus for sealing trays with an aluminium foil, having a carrier plate for the tray which can be lifted and lowered with the tray and folding tools for bending that portion of the aluminium foil extending beyond the edges of the trays under the bent edge of the tray. The folding tools comprise slides which can be moved against the tray from the outside and which are mounted or designed, and operate conjointly with closing brackets or other actuation means, in such a manner that, during the bending operation, the edges of the aluminium foil are first pressed against the tray from the outside and, during the final phase, are pressed into the hollow behind the edge of the tray from below. This ensures an especially secure, tight closure between foil and tray in one step.

Description

United States Patent 1 Schierle 51 May 13,1975

[ APPARATUS FOR BENDING THE EDGE OF A FOIL AROUND THE EDGE OF A TRAY [76] Inventor: Eugen Schierle, in den Ringelgarten 58, D-7000 Stuttgart, Germany [22] Filed: Oct. 19, 1973 [211 Appl. No.: 408,111

[30] Foreign Application Priority Data Oct. 27, 1972 Germany 2252927 [52] US. Cl. 53/354 [51] Int. C1. B65B 7/28; B67B 3/14 [58] Field of Search 53/329, 344, 345, 346, 53/342, 350, 378, 371, 364, 365, 290, 296, 297, 354

[56] References Cited UNITED STATES PATENTS 2,704,628 3/1955 Stanton, Jr. et al. 53/344 3,036,416 5/1962 Cheeley et al. 53/354 X 3,224,163 12/1965 Ray 53/329 3,253,380 5/1966 Cheeley et al. 53/345 X 3,261,144 7/1966 Weber 53/344 Primary Examiner-Travis S. McGehee Assistant E.\'aminerHorace M. Culver Attorney, Agent, or FirmCraig & Antonelli [57] ABSTRACT An apparatus for sealing trays with an aluminium foil, having a carrier plate for the tray which can be lifted and lowered with the tray and folding tools for bending that portion of the aluminium foil extending beyond the edges of the trays under the bent edge of the tray. The folding tools comprise slides which can be moved against the tray from the outside and which are mounted or designed, and operate conjointly with closing brackets or other actuation means, in such a manner that, during the bending operation, the edges of the aluminium foil are first pressed against the tray from the outside and, during the final phase, are pressed into the hollow behind the edge of the tray from below. This ensures an especially secure, tight closure between foil and tray in one step.

11 Claims, 4 Drawing Figures PATE T HAY 1 3197's SHEET 10F 2 APPARATUS FOR BENDING THE EDGE OF A FOIL AROUND THE EDGE OF A TRAY The present invention relates to an apparatus for bending the edge of a foil of aluminium or a similar material around the edge of a tray, having a centering basket and a stop plate, which hold the tray and the foil between them and which can be advanced one toward the other, and further having slides which contact the edge of the foil from the outside as it bends during the advancing movement.

In a known apparatus of this type (US. Pat. No. 3,036,416), the tray and the lid foil are advanced against a stop plate, which is then taken along and placed against a sealing apparatus. This sealing apparatus has downwardly protruding edges, which bend the lid foil toward the tray. The bent edges of the lid foil are then pressed against the tray by means of slides which can be advanced toward the tray. A separate drive, taken from a cam disc, is provided for the slides, with the drive moving the slides diagonally to the tray, whose surface is generally rectangular. With the aid of this apparatus, the edges of the lid foil are only bent around the edges of the tray, without mutual tensioning. The danger exists that sufficient tightness cannot be achieved in this manner, as at least a drip-proof closure must be ensured if containers sealed in this manner are to be employed for the storage of foods or similar items.

The object of the invention is to create an apparatus of the type indicated at the outset which ensures a dripproof sealing of the tray by means of the lid foil. According to the invention the centering basket has a closing bracket which is movable in the direction of advance and which contacts the slides, which are movable in the direction of advance, in the final position of the centering basket and the stop plate. This presses the slides against the stop plate to complete the sealing operation and tension the edge of the lid foil and the tray with one another to form a tight sea].

In a development of the invention, the slides are pivotally arranged about shafts which extend parallel to the edges of the tray. This pivotal arrangement of the slides, whose swivel shaft is located above the stop plate, has a favourable effect on the operation of bending the edges of the lid foil against the side walls of the tray, as the edges are pressed from the top to the bottom.

In an additional advantageous development of the invention, there are levers between a base plate and the stop plate, which is in a movable supporting relationship with the base plate against the effect of one or more springs, with the levers supporting the slides by means of rod-like attachments located laterally next to the stop plate. This arrangement and design of the slides ensures that the normal advance movement when the tray and the lid are loaded is transmitted into a swivel movement to be performed by the slides, without requiring further drive means.

In an additional advantageous development of the invention, only those sections of the slides located in the straight-line area of the edges of the tray, which has rounded corners in a known manner, are movable in the direction of advance, thereby avoiding additional pressing of the two edges in the area of the corners. Actual practice has shown that the pleating of the lid foil occurring in the area of the corners provides sufficient tightness, without axial pressing being required. This provides the additional advantage that the corners of the lid foil can be extended downward and utilized as pull tabs for opening the tray. In a practical embodiment of the invention, the movable sections of the slides are retained on the rodlike attachments with springs.

In order to prevent the edge of the tray, which usually has an annular bead, from being destroyed during sealing, it is advantageous if the plate-shaped slides have a stem which engages behind an annular bead of the edge of the tray, thereby limiting pressing between the edges of the lid foil and the tray to a certain area.

It is structurally advantageous if the corner sections of the slides, which contact the corner sections of the neighbouring slides in the closed position, are set back relative to the straight moving sections, thereby making the closure of the corners less intensive, which however is not disadvantageous for the above mentioned reason. This design permits the advantage that, in a further development of the invention, the corners of the centering basket have extensions which extend right to the edge of the tray. This permits forces of relatively large magnitude to be transmitted to the stop plate from the centering basket without crushing the tray.

In order to avoid having to also provide separate drive means for the centering basket and the closing bracket, in a further development of the invention the centering basket is kept in a supporting relationship with the closing bracket by means of one or more springs which are stronger than the springs which retain the stop plate. This ensures that the closing bracket is not moved until the centering basket and the stop plate have moved to their final position.

In order to bend the edge of the lid foil as the tray and the lid foil which are held in the centering basket are pressed against the stop plate, it is advantageous if the stop plate has a recess corresponding to the size of the lid to be created.

The above discussed and other objects, features and advantages of the present invention will become more apparent from the following description thereof, when taken in connection with the accompanying drawings, in which FIGS. 1a and lb show a vertical section through an embodiment according to the invention in the initial position and in the closed position; and

FIGS. 2a and 2b show a top view of lateral slides in the initial position and in the closed position.

With the apparatus according to the invention, trays 1, which are preferably of aluminium foil or a similar metallic foil, are to be sealed automatically with a foil 2, which is also an aluminium foil or another metallic foil. Tray 1 and foil 2 are represented by dash-dotted lines. Tray 1 has an outwardly projecting edge, which has an annular bead 3 on the outside. Foil 2 is bent around annular bead 3 of this edge, whereby a dripproof closure should be achieved, as trays of this type are employed especially for the storage of prepared foods.

Filled tray 1 is placed in a centering basket 4 automatically by means of an unillustrated apparatus; the inclination of the side walls of centering basket 4 correspond to the inclination of the side walls of tray 1. The corners of centering basket 4 have extensions 5, which are in a contacting relationship with the edge of tray 1 "mm the bottom. Foil 2 is also placed on tray I auto: rnatically in an unillustrated manner.

The centering basket is lifted by means of a piston 6,

and advanced against a stop plate 7. The bottom of stop plate 7 has a recess S corresponding generally with the lid to be produced, so that the edge of foil 2 is bent :lownward around annular bead 3 when centering basket 4, containing tray 1, is pressed against stop plate 7.

Stop plate 7 is slidably arranged in a base plate 11 by means of a piston 9 against the effect of a spring 10,.

and its movement is limited by means of a stop 12 surroundingpiston 9. When tray 1 and foil 2 are pressed against stop plate 7 by centering basket 4, stop plate 7 can yield a given distance until it contacts its stop 12. This movement is transmitted to slides 14 in a lateral movement by means of levers 13 arranged between base plate 11 and stop plate 7. Levers 13, which must be inclined relative to the direction of advance of centering basket 4, are mounted between stop plate 7 and base plate 11 in

bearing blocks

15 and 16, with a slot guide being provided in bearing blocks 16 of base plate 11. Swivel shaft 17 of bearing blocks 15 extends vertically above the edges of tray 1 and parallel thereto.

Rod-like attachments 18 protrude downward from le- Slides 14 are movably attached to rod-like attach-.

ments 18 in the direction of the advance of centering basket 4 and the sliding movement of stop plate 7, and

. like attachments 18. In addition, section 26 is'set back relative to section with respect to the side walls of tray 1. Furthermore, only section 25 has a stemf21..,

are retained in the initial position shown in FIG. 1a by means of springs 19. As a result of this movable attach-. ment, slides 14 can be moved upward by means of a closing bracket 20 when centering basket 4 and stop plate 7 have reachedtheir end positions. As can be seen from FIG. 1b, this swivels slides 14 upward above rod-like attachments 18. They engage behind bead 3 of the edge of tray 1 with a stem 21, and press the edge of foil 2, which is bent around bead 3, upward, thus producing a secure connection which is at least dripproof. I

In order to avoid having to provide separate drive means for closing bracket 20, centering basket 4 is movably supported against piston 6 by means of bolts 22 and springs 23, while closing bracket 20 is connected directly with piston 6. Together, springs 23 must be at least so strong that they will only compress when spring 10 has compressed so far that stop 12 contacts stop plate 7. This can be ensured in a simple manner through the selection of suitable pre-tensions. Closing bracket 20 is cross-shaped, so that it only contacts the center areas of slides 14 from below.

Base plate 11 is supported on rods 24. Of course, it is also quite possible to reverse the direction of travel, and to design centering basket 4 and closing bracket 20 stationary with base plate 11 and the other components of this assembly being advanceable.

As can be seen from FIGS. 2a and 217, there are four slides 14, which are associated to the side walls of tray 1. The slides are divided into two

independent sections

25 and 26, with section 25 associated to the straight area of the edges of tray 1 and each section '26 associatedtoa half corner areaonlysection 25 isimovably retained against rod-like attachments 18, in accordance with the representation according toFlGS. 1a and 1b, while section 26 is fixedly connected with rod- As can be seen from FIG. 2b in particular, sections 26 of the neighbouring slides 14 contact one another when the apparatus is. closed. They leave sufficient clearance to the corner of tray 1 for extensions, 5 of,

centering basket 4 to be able to move right to the edge of tray 1 in the corner areas. As a result, the corner areas are not sealed as intensively as the straightiareas. In actual practice, this has not proven to be a disadvantage, but an advantage, since sufficientsealing is provided in the corner areas by the compression of the lid foil there, the so-called pleating. In addition,pull tabs. 6

can also be left on lid foil 2 in the corner areasythis permits advantageous opening of the trays by pulling these.

pull tabs downward.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It should therefore be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.-

Having .thus fully disclosed my invention, what I.

claim is: g 1. An apparatus for bending the edge of a foil of aluminium or a similar material around an outwardly projecting edge of a tray, the tray being provided 'with straight edge portions and corner portions connecting the straight edge portions, the apparatus comprising; a base plate means, a centering basket means for receiv-,--

ing and holding the tray with the foil disposed there} over, a stop plate means disposed aboveand spaced from said centering basket means, meansfor selectively displacing said centering basket means into eng g ment with said stop plate means, means for mounting".

said stop plate means to permit limited displacement means in the first direction being effectedby the limited displacement of said stop plate means by saidcentering basket means, and a closing bracket means mov able with said centering basket means forcontacting said slide means to effect movement of said slide means I I in the. second direction after'said centering basketm means contacts said stop plate means.

2. The apparatusaccording to claim 1, in which said: means for mounting said slide means includes'lever means disposed at respective lateral edges of said stop plate means, said lever means extending between said base plate means and a respective lateral edge ofsaid stop plate means, and at least a pair of spaced shaft means for pivotally .mounting'the respective ends of said lever means, one of said pair of spaced shaft means being mounted at said stop plate member and the other a I of said pair of shaft means being mounted at said base. f

plate means, each of said shaft means extending parallel to the edges of thetray.

3. The apparatus according to claim 2, in which spring means are provided for normally urging said stop plate means toward the centering basket means, and attachment means located laterally of said stop plate means for attaching said slide means to said lever means.

4. The apparatus according to claim 3, in which said slide means includes a slide member, said attachment means includes a rod member mounted on said lever means, a stop shoulder provided at one end of said rod member, and spring means for normally urging said slide member toward said stop shoulder.

5. The apparatus according to claim 1, in which each of said slide means includes a first member extending substantially parallel to the straight edge portion of the tray and a second member contoured to a portion of the corner portions of the tray, said first member of each of said slide means being mounted to effect the successive movement in the first and second directions and said second member being fixedly mounted with respect to said first member.

6. The apparatus according to claim 5, in which said second members of said slide means are set back relative to said first members to permit adjacent second members of adjacent slide means to contact each other after said first members effect the successive movements in the first and second directions.

7. The apparatus according to claim 1, in which said slide means includes plates, and stem means for engaging behind an annular bead of the edge of the tray to seal the foil thereto.

8. The apparatus according to claim 1, in which the centering basket means is provided with corners, said corners have extensions extending to the edge of the tray.

9. The apparatus according to claim 8, in which spring means for supporting said centering basket means are provided between said centering basket means and said closing bracket means, said lastmentioned spring means being stronger than the spring means for normally biasing said stop plate means toward said centering basket means.

10. The apparatus according to claim 8, in which a recess corresponding to the size of a lid to be created by the foil is provided in said stop plate means.

11. An apparatus for bending the edge of a foil of aluminium or a similar material around a surrounding edge of a tray, the foil being provided with edges extending beyond the edge of the tray, the apparatus comprising: a carrier plate means for carrying the tray, a pre-bending means disposed above said carrier plate means for bending portions of the foil which extend beyond the edges of the tray, means for selectively raising and lowering said carrier plate means, said carrier plate means in said raised position engaging said pre-bending means to permit said pre-bending means to bend the foil extending beyond theedgcs of the tray toward said carrier plate means, sealing means operatively connected with said carrier plate means and said prebending means for pressing the portions of the foil bent toward said carrier plate means around the edge of the tray, means for mounting said sealing means to permit successive movement of the same in a first direction toward the tray and, a second direction substantially perpendicular to the edge of the tray, and a closing bracket means movable with said carrier plate means for contacting said sealing means and pushing said sealing means in the second direction when said carrier plate means and said pre-bending means are in engagement. l =l

Claims

1. An apparatus for bending the edge of a foil of aluminium or a similar material around an outwardly projecting edge of a tray, the tray being provided with straight edge portions and corner portions connecting the straight edge portions, the apparatus comprising: a base plate means, a centering basket means for receiving and holding the tray with the foil disposed thereover, a stop plate means disposed above and spaced from said centering basket means, means for selectively displacing said centering basket means into engagement with said stop plate means, means for mounting said stop plate means to permit limited displacement thereof by said centering basket means, a plurality of slide means for contacting and bending the respective edges of the foil from the outside thereof, pivot means connected with said base plate means and said stop plate means for pivotally mounting said slide means to permit at least a portion of said slide means to effect successive movement in a first direction toward the tray and in a second direction substantially perpendicular to the edge of the tray, the movement of said slide means in the first direction being effected by the limited displacement of said stop plate means by said centering basket means, and a closing bracket means movable with said centering basket means for contacting said slide means to effect movement of said slide means in the second direction after said centering basket means contacts said stop plate means.

2. The apparatus according to claim 1, in which said means for mounting said slide means includes lever means disposed at respective lateral edges of said stop plate means, said lever means extending between said base plate means and a respective lateral edge of said stop plate means, and at least a pair of spaced shaft means for pivotally mounting the respective ends of said lever means, one of said pair of spaced shaft means being mounted at said stop plate member and the other of said pair of shaft means being mounted at said base plate means, each of said shaft means extending parallel to the edges of the tray.

9. The apparatus according to claim 8, in which spring means for supporting said centering basket means are provided between said centering basket means and said closing bracket means, said last-mentioned spring means being stronger than the spring means for normally biasing said stop plate means toward said centering basket means.

11. An apparatus for bending the edge of a foil of aluminium or a similar material around a surrounding edge of a tray, the foil being provided with edges extending beyond the edge of the tray, the apparatus comprising: a carrier plate means for carrying the tray, a pre-bending means disposed above said carrier plate means for bending portions of the foil which extend beyond the edges of the tray, means for selectively raising and lowering said carrier plate means, said carrier plate means in said raised position engaging said pre-bending means to permit said pre-bending means to bend the foil extending beyond the edges of the tray toward said carrier plate means, sealing means operatively connected with said carrier plate means and said pre-bending means for pressing the portions of the foil bent toward said carrier plate means around the edge of the tray, means for mounting said sealing means to permit successive movement of the same in a first direction toward the tray and, a second direction substantially perpendicular to the edge of the tray, and a closing bracket means movable with said carrier plate means for contacting said sealing means and pushing said sealing means in the second direction when said carrier plate means and said pre-bending means are in engagement.