The present invention relates to the field of food wrapping and packaging machines, and more particularly to the field of manual food wrapping machines.

Food wrapping machines are known. In use, usually, food is inserted into an open-top vessel or container, typically in a size of a plate, and then, a sealing film is put on top of the container, the sealing film is soldered to the perimeter of the container, and finally, the sealing film is cut, and the sealed container is taken out in order to make room for another container.

Some examples to these kinds of machines are shown by "TPS MINI TRAYPACKER" by "HENKOVAC", or by "FP BASIC" Sealer by "RTG" Roberts Technology Group, Inc. In these kinds of machines, the soldering is done by the pressure of a pneumatic piston and therefore the machines require a connection to a pressurized air line, a great disadvantage in small stores that, contrary to large plants, are not provided with pressurized air infrastructure. The rolling of the wrapping film is done by an electric motor, and the controlled environment is done by suction of a vacuum pump. The cutting of the wrapping film is "shaped", i.e., around and adjacent the lip of the packed container.

Other tray sealer machines, e.g., S 220 SP by "VAC-STAR" AG, have shape cutting but do not have automatic rolling of the film. This kind of machine suffers from the following disadvantages; (a)- requires a pressurized air line, (b)- has relatively high energy consumption, (c)- slow working speed, due to the manual rolling.

Other types of sealer machines are manual machines, like, e.g., VS300 Tray Sealer Udder by "SMS", or, Sealing Machine DF25 by "Duni Store". These machines suffer from the following disadvantages; (a)- perform soldering only, (b)- do not provide a controlled environment, (c)- the rolling is done totally manual, by pulling and arranging the film, (d)- bad appearance, due to un-shaped cutting of the film according to the trays' shape, (e)- requires a pressurized air line, (f)- relatively high energy consumption, (g)- slow working speed, due to the manual rolling.

The wrapping machines vary in their size and functionality. Typically, these wrapping machines are large and require a specially assigned room for operation, therefore, they are not suitable for operation on a limited space of a grocery store or the like.

There are wrapping machines for wrapping food in a controlled environment. These machines require a large surrounding envelope or room. During operation, these machines are inserted into the surrounding envelope when the container with the food is about to be sealed. In this position, the air is sucked away from the surrounding envelope, and another gas, e.g., nitrogen or carbon-dioxide, is inserted into the surrounding envelope. In other cases, no other gas is inserted into the surrounding envelope, and the food is wrapped in vacuum. Now, the container with the food is sealed with a sealing film that is soldered to the perimeter of the container.

These kinds of machines suffer from the disadvantage that they require a large volume for operation, and spend a lot of energy and controlling gases in order to replace the entire environment in the surrounding envelope.

A solution to this problem is disclosed in US Pat. No. 6,912,828 to Yamay. The '828 patent discloses a packaging method and apparatus for wrapping food in a controlled environment. This is done by introducing a container having a cap shape and a rigid or semi rigid body. The container is provided with a rim, and, a closure-forming member is placed adjacent the rim and slightly distanced away therefrom. A replacement gas is flown through an inlet to an outlet, and, in its way, replaces at least a substantial portion of the gas originally contained in the container.

Other types of manual food wrapping machines have means for soldering a sealing film to the rim of the container containing the food. However, these types of machines suffer from several disadvantages. First, the sealing film is not automatically pulled and dispensed to the required length and stretched over the lid of the container. Second, if the machine is provided with means for cutting the sealing film, they are usually in a form of a knife that is acting in a straight line, in a direction perpendicular to the pulling direction of the sealing film. This action leaves unnecessary portion of sealing film attached to the container, a fact that causes unnecessary spending of sealing film, and, causes bad visual appearance of the sealed container, since the cut sealing film is not in the form of the lid of the container.

WO 2012/005678 discloses an apparatus and method in accordance with the preambles of claims 1 and 27 respectively.

It is the object of the present invention to provide a manual food wrapping apparatus that significantly reduces or overcomes the aforementioned disadvantages.

It is a further object of the present invention to provide a manual food wrapping apparatus that is easy to implement and use.

It is still a further object of the present invention to provide a manual food wrapping apparatus that enables food wrapping in a controlled environment.

It is still yet a further object of the present invention to provide a manual food wrapping apparatus that enables a set or dispensed rolling and pulling of the sealing film, neatly stretching the sealing film, and shaped-cutting thereof according to the shape of the container to be sealed.

It is also an object of the present invention to provide a manual food wrapping apparatus that performs the several steps of food wrapping in a controlled environment, in a single manual movement.

It is another object of the present invention to provide a manual food wrapping apparatus that is smaller than similar industrial machines performing similar tasks, and is easily transported and placed on top of any table or 5 refrigerator, thus enabling its use in small grocery stores.

It is still another object of the present invention to provide a manual food wrapping apparatus that provides food wrapping in a controlled environment, thus extending shelf-life of the product within the sealed container.

It is still yet another object of the present invention to provide a process for manual food wrapping in a controlled environment.

It is also another object of the present invention to provide a process for neatly, quickly, easily and efficiently, wrap and seal a top of a food container in a controlled environment.

In accordance with the present invention there is provided a manual wrapping apparatus for wrapping a tray with a sealing film with the features specified in claim 1. The apparatus according to the invention comprises:

• a lower frame and an upper arm hinged to the lower frame,
• the lower frame comprising a tray receiving bracket for receiving therein the tray, wherein
• manually closing the upper arm toward the lower frame manually feeds forwardly the sealing film, replaces the atmosphere within the tray, solders the sealing film to the tray, and, cuts the sealing film around the tray.

Commonly, the apparatus is a food wrapping apparatus.

The apparatus of the invention comprises a feeding system comprising a feeding system rear portion and a feeding system front portion,
the feeding system rear portion comprises:

• a feeding cam, provided with a feeding gear, that is connected to the upper arm, the feeding cam forms a sector of 45° to 90° that rotates around a main operation axis (A) of the upper arm with respect to the lower frame,
• a film driving roll and a film tightening roll that is parallel to the film driving roll and interconnected therewith,
• an engagement member connects between the feeding system rear portion and the feeding system front portion,
• the feeding system front portion comprises:
  • a front film driving roll and a front film tightening roll that is parallel to the front film driving roll and interconnected therewith,
  • at the feeding system rear portion the sealing film passes between the film driving roll and the film tightening roll, at the feeding system front portion the sealing film passes between the front film driving roll and the front film tightening roll, and, wherein
  • movement of the upper arm toward the lower frame, between an open position of the upper arm to a closed position of the upper arm, causes the feeding gear to turn the feeding system rear portion and the feeding system front portion at the same amount thus feeding forwardly the sealing film at a constant and measured value.

In some embodiments, the feeding cam forms a sector of 70°.

Practically, the film tightening roll and the front film tightening roll are provided with a plurality of equally spaced apart grooves, and, a tightening ring is received within each of the grooves.

Further practically, the sealing film remains straight and tight by being squeezed by the tightening rings of the corresponding film tightening roll and the front film tightening roll against the corresponding film driving roll and the front film driving roll.

Conveniently, the apparatus is provided with a film positioning bracket for easy loading the sealing film into a working position, the film positioning bracket is rotatable with respect to the main operation axis (A) and comprising the film driving roll and the front filth driving roll, and wherein in an open position of the film positioning bracket the sealing film may be freely put on the tray receiving bracket.

If desired, the lower frame comprises a right side bracket and a left side bracket that are connected inbetween by means of tightening rods, and
the film positioning bracket is locked to the right side bracket and to the left side bracket by means of bracket secure knobs, each of the bracket secure knobs having a securing pin that is located within a pin receiving hole formed in the film positioning bracket.

Advantageously, the tray receiving bracket is interchangeable.

Typically, the tray receiving bracket comprising:

• a tray receiving aperture for receiving the tray therein,
• a tray receiving shoulder, peripherally surrounding the tray receiving aperture, for receiving thereon a peripheral shoulder of the tray,
• a knife receiving groove extending peripherally around the tray receiving shoulder and bounded by a bracket top surface,
• the tray receiving bracket further comprising:
  • at least one gas inlet hole that opens at least to the knife receiving groove,
  • at least one gas outlet hole that opens at least to the knife receiving groove, and a gas valve operating switch,

If desired, the at least one gas inlet hole opens to the knife receiving groove and to the bracket top surface.

Practically, the gas valve operating switch protrudes upwardly from the bracket top surface.

Advantageously, the tray receiving shoulder comprises a vertically formed seal slot extending at an entire periphery of the tray receiving shoulder, and
a sealing element located within the seal slot and on top of the tray receiving shoulder.

In most cases, the engagement member connecting between the feeding system rear portion and the feeding system front portion constitutes a belt.

Practically, the belt is toothed according to a belt driving gear of the feeding system rear portion and according to a belt receiving gear of the feeding system front portion.

Typically, the upper arm comprises a pressing plate that is urgedc downwardly and hanged from a base plate of the upper arm by means of pressing plate hanging members, and wherein
the pressing plate hanging members may freely pass through the base plate such that the distance between the pressing plate and the base plate may vary during various steps of operation of the apparatus.

If desired, a lower portion of the pressing plate is provided with a pressing gasket.

Typically, the upper arm comprises a soldering platform that is urged downwardly and hanged from the base plate of the upper arm by means of soldering platform hanging members, and wherein
the soldering platform hanging members may freely pass through the base plate such that the distance between the soldering platform and the base plate may vary during various steps of operation of the apparatus.

Practically, the soldering platform comprises a heating element in an upper portion thereof and a soldering lip in 'a lower portion thereof.

Typically, a knife is surrounding the soldering platform slightly distanced away therefrom, an upper portion of the knife is bounded by a knife base that is rigidly connected to the base plate, and, a lower portion of the knife constitutes a cutting edge.

Advantageously, the lower frame comprises a tray removing mechanism for urging upwardly the tray.

Practically, the tray removing mechanism comprises a tray removing handle that is oppositely positioned to a lifting lever with respect to a handle shaft, and wherein
urging the tray removing handle in a downward direction urges the lifting lever in an upward direction for urging upwardly the tray.

If desired, the apparatus comprising an operating handle extending along a width dimension of the apparatus and rotatable with respect to the upper arm, the operating handle comprising:

• a holding portion, and
• a stroke releasing handle, and wherein
• in a non operating position of the stroke releasing handle the operating handle may rotate a first given stroke, and
• in an operating position of the stroke releasing handle the operating handle may rotate a second given stroke that is larger than the first given stroke.

Typically, a stroke releasing lever extends from the stroke releasing handle, the stroke releasing lever ends with a protrusion nested within a locking slot formed in the upper arm, and

pressing the stroke releasing handle toward the holding portion releases the protrusion from the locking slot thus enabling further rotation of the operating handle.

Practically, the holding portion extends between two operating frames, each of the operating frames comprises a sliding buffer comprising:

• a flat slanted surface at a forward portion of the sliding buffer,
• a sliding surface extending rearwardly from the slanted surface, and
• a sliding limiting wall rearwardly to the sliding surface, and wherein
• the lower frame is provided with a pressure support rod located adjacent the slanted surface prior to operating the stroke releasing handle, and
• a downward movement of the operating handle urges the sliding buffer to gradually enter under the pressure support rod thus gradually urging downwardly the upper arm.

Typically, the weight of the upper arm is counterbalanced by two balancing pistons.

Advantageously, the feeding system rear portion is provided with at least one ratchet for enabling forward feeding of the sealing film during downward movement of the upper arm, and, preventing rearward pulling of the sealing film during upward movement of the upper arm.

Further in accordance with the present invention there is provided a method for manually wrapping a product within a cup-shaped tray in a controlled environment by a sealing film, the method comprising the steps of:

1. (a) Providing an apparatus according to the invention having an upper arm hinged to a lower frame, and a sealing film roll is seated within a sealing film support portion of the lower frame.
2. (b) Inserting the tray into a tray receiving aperture formed in a tray receiving bracket that is connected to the lower frame,
3. (c) Pulling down a holding portion of an operating handle, between an open position of the upper arm and a closed position of the upper arm, for operating a feeding system for feeding forwardly the sealing film at a constant measure, holding the sealing film in position, soldering the sealing film to the tray, and, cutting the sealing film around the tray.
4. (d) Removing the tray by pressing a tray removing handle of a tray removing mechanism.

If desired, the method further comprising in step (c), after soldering the sealing film to the tray, the step of:

• (e) Providing a stroke releasing handle that is pulled in order to enable further stroke of the holding portion for cutting the sealing film around the tray.

For a better understanding of the present invention and to show how the same may be carried out in practice, reference will now be made to the accompanying drawings, in which:

Fig.1

is a perspective view of a manual food wrapping apparatus according to the present invention;

Fig. 2

is a top view of the apparatus of Fig. 1;

Fig. 3

is a side view of the apparatus of Fig, 1;

Fig. 4

is a side cross-sectional view of the apparatus of Fig. 1, taken along line IV-IV in Fig. 2, shown in an open position;

Fig. 5

is a side cross-sectional view of the apparatus of Fig, 1, taken along line IV-IV in Fig. 2, shown in a closed position;

Fig. 6

is a partial perspective view of the rear portion of the feeding system;

Fig. 7

is a front view of the partial rear portion of the feeding system shown in Fig. 6;

Fig. 8

is a side view of the partial rear portion of the feeding system shown in Fig. 6;

Fig. 9

is a partial perspective view of the front portion of the feeding system;

Fig. 10

is a perspective view of the apparatus with the film positioning bracket in a lifted position;

Fig. 11

is a top view of the tray receiving bracket;

Fig. 12

is a cross-sectional view of the tray receiving bracket taken along line XII-XII in Fig. 11;

Fig. 13

is a cross-sectional view of the tray receiving bracket taken along line XIII-XIII in Fig. 11;

Fig. 14

is a partial cross-sectional view of the apparatus in a first wrapping stage taken along line XIII-XIII in Fig, 11;

Fig. 15

is a partial cross-sectional view of the apparatus in a second wrapping stage taken along line XIII-XIII in Fig. 11;

Fig. 16

is a partial cross-sectional view of the apparatus in a third wrapping stage taken along line XIII-XIII in Fig. 11;

Fig. 17

is a partial cross-sectional view of the apparatus in a fourth wrapping stage taken along line XIII-XIII in Fig. 11;

Fig. 18

is a partial cross-sectional view of the apparatus taken along line XII-XII in Fig, 11 in a position prior to removing the tray;

Fig. 19

is a partial cross-sectional view of the apparatus taken along line XII-XII in Fig. 11 in a tray removing position;

Fig. 20

is a partial side cross-sectional view of the locking handle in the first wrapping stage;

Fig. 21

is a partial side cross-sectional view of the locking handle in the fourth wrapping stage;

Attention is drawn to Figs. 1 to 5 that show a manual food wrapping machine or apparatus 10 according to the present invention. For a matter of simplicity, the manual food wrapping or packaging apparatus 10 will hereinafter be called "apparatus".

Since the apparatus 10 is mainly used in the food industry, it is preferable that it is made from stainless steel, so it will not rust and be easy to clean. The apparatus 10 comprises a lower frame 12 and an upper arm 14 hinged to the lower frame 12. The upper arm 14 rotates around a main operation axis A with respect to the lower frame 12, and the weight of the upper arm 14 is counterbalanced by two balancing pistons 16.

Each of the balancing pistons 16 is located at an opposite side of the apparatus 10, namely, a first balancing piston 16 is located at a right side 18 of the apparatus 10, and a second balancing piston 16 is located at a left side 20 of the apparatus 10. Each of the balancing pistons 16 is hinged to the lower frame 12 at a piston lower end 22, and to the upper arm 14 at a piston upper end 24.

The lower frame 12 comprises a right side bracket 26 that is connected to a left side bracket 28 by a multitude of tightening rods 30. Typically, each of the tightening rods 30 is tightened, at both ends thereof, to each of the brackets 26, 28 by means of a tightening bolt 32.

It should be noted that directional terms appearing throughout the specification and claims, e.g. "forward", "rear", "upper", "lower" etc., are used as terms of convenience to distinguish the location of various surfaces relative to each other. These terms are defined with reference to the figures, however, they are used for illustrative purposes only, and are not intended to limit the scope of the appended claims.

A rear end 34 of the lower frame 12 comprises a sealing film support portion 36. The sealing film support portion 36 comprises two support rods 38 that are located parallel to each other and connected, at both ends thereof, to the right side bracket 26 and to the left side bracket 28. The support rods 38 are typically hollow pipes made of PVC or plastic, however, they may be equally formed from stainless steel or the like. Each of the support rods 38 may freely rotate, with respect to the lower frame 12, around a support rod longitudinal axis B. The free rotation of each of the support rods 38 is enabled by means of a bearing or a bushing (not specifically shown).

A spacer 40 is rigidly mounted on each end of the support rods 38. Each spacer 40 is slightly distanced from the adjacent bracket 26, 28 and is free to rotate together with the support rod 38 that is inserted within. A sealing film roll 42 of a sealing film 43 is placed on the support rods 38. The sealing film roll 42 has a sealing film roll axis C, and is placed parallel to the support rods 38 and between the spacers 40. The purpose of the spacers 40 is to assure that while the sealing film roll 42 rolls on the support rods 38, by the pulling of the sealing film 43 as will be later described, the sealing film roll 42 is centered with respect to the right side bracket 26 and the left side bracket 28 therefore assuring even pulling and feeding of the sealing film 43 so that it constantly looks tight and has no wrinkles.

According to a specific mode of use of the present invention, the sealing film roll 42 is directed such that the sealing film 43 is pulled from an upper portion of the sealing film roll 42, however, if required, the sealing film roll 42 may be directed such that the sealing film 43 is pulled from a lower portion of the sealing film roll 42. Typically, the sealing film 43 is directional-related, i.e., both sides of the sealing film 43 have different qualities and it is pre-set which side will be subjected to the sealing heat and which side will be soldered to the food tray.

Attention is now drawn to Figs. 6 to 9 that show a feeding system 44 of the apparatus 10. Generally, the feeding system 44 comprises a feeding system rear portion 46, shown in Figs. 6 to 8, and, a feeding system front portion 48, shown in Fig. 9. The feeding system 44 is symmetrical, unless otherwise mentioned, with respect to a longitudinal median plane P of the apparatus 10 (see Fig. 2), Therefore, for a matter of simplicity, only a right side of the feeding system 44 will be described, i.e., the side adjacent the right side bracket 26.

The feeding system 44 comprises a feeding cam 50 that is connected to the upper arm 14. The feeding cam 50 is the only part of the feeding system 44 that is connected to the upper arm 14 and all the other parts of the feeding system 44, as will be now described, are connected to the lower frame 12.

The feeding cam 50 forms a sector of 45° to 90° that rotates around the main operation axis A. According to a specific embodiment of the present invention, the feeding cam 50 forms a sector of 70°. A front portion of the feeding cam 50 is toothed and forms a portion of a feeding gear 52.

The feeding gear 52 is engaged with a feed receiving gear 54 that forms a part of a film driving roll 56 that rotates around a film driving roll axis D. The film driving roll 56 is provided with a driving gear 58 that is engaged with a drive receiving gear 60. The drive receiving gear 60 forms a part of a film tightening roll 62 that rotates around a film tightening roll axis E.

A ratchet 63 is connected, preferably at each side of the film driving roll 56, between the feed receiving gear 54 and the driving gear 58. The purpose of the ratchet 63 is to enable forward feeding of the sealing film 43 during downward movement of the upper arm 14, and, to prevent rearward pulling of the sealing film 43 during upward movement of the upper arm 14.

The film tightening roll 62 is provided with a plurality of equally spaced apart grooves 64. Each groove 64 has a semi-circular cross-section in order to receive therein a tightening ring 66 which is elastic and can be made from silicone, rubber, or the like. For a purpose of demonstration, Fig. 7 shows the film tightening roll 62 with one of the tightening rings 66 removed so that the groove 64 underneath can be seen.

The film driving roll axis D is parallel to film tightening roll axis E and distanced away therefrom such that during operation of the apparatus 10, the tightening rings 66 are slightly squeezed against the film driving roll 56, thus, when the sealing film 43 passes between the film driving roll 56 and the film tightening roll 62, it remains flat and tight.

The film tightening roll 62 is provided, at one end thereof, with a belt driving gear 68 for driving a belt 70. Typically, the belt 70 is toothed in an inward portion thereof. The teething of the belt 70 corresponds to the teething of the belt driving gear 68.

The feeding system front portion 48 comprises a front film driving roll 72, and, a front film tightening roll 74 that rotates around a front film tightening roll axis G that is parallel to a front film driving roll axis F. The front film tightening roll 74 is provided with a plurality of grooves (not shown), and a tightening ring 66 is located in each of the grooves, similar to the matter as was described with respect to the film tightening roll 62.

At one end thereof, the front film tightening roll 74 is provided with a belt receiving gear 76 for receiving thereon the belt 70.

As can be best seen in Fig. 10, the film driving roll 56 and the front film driving roll 72 are assembled onto a film positioning bracket 78 that is rotatable with respect to the main operation axis A. The film positioning bracket 78 enables easy loading of the sealing film 43 into a working position. During rotation of the film positioning bracket 78, the feed receiving gears 54 of the film driving roll 56 advance on their corresponding feeding gear 52 of the feeding cam 50. The front film driving roll 72 freely rotates with respect to the film positioning bracket 78 around the front film driving roll axis F.

The film positioning bracket 78 is secured in position by means of a pair of bracket secure knobs 80 (see the enlargement portion in Fig. 10) that are connected to the lower frame 12. A first bracket secure knob 80 is connected to the right side bracket 26 and a second bracket secure knob 80 is connected to the left side bracket 28. The bracket secure knobs 80 are retractable with respect to the side bracket 26,28 they are mounted thereon. Each of the bracket secure knobs 80 has a protruding securing pin 82 that is positioned, in a locked position of the film positioning bracket 78, within a corresponding pin receiving hole 84.

A central portion of the lower frame 12 comprises a tray receiving bracket 86. The tray receiving bracket 86 is supported by a pair of bracket support rods 88 that are attached to the lower frame 12 by means of securing bolts 90 that can be easily disassembled in order to enable replacing the tray receiving bracket 86 with another tray receiving bracket having different shape or size.

The tray receiving bracket 86 comprises a tray receiving aperture 92 that is peripherally bounded by a tray receiving shoulder 94. A top surface of the tray receiving shoulder 94 is covered with a flexible sealing element 96 for supporting the tray to being sealed. Typically, the sealing element 96 is made of silicone, however, other materials may be equally applied. According to some embodiments, the sealing element 96 is T-shaped, having a vertical leg and a horizontal leg connected thereto, thus, the vertical leg can be inserted into a corresponding vertical seal slot 98 formed in an upper portion of the tray receiving shoulder 94. In this manner, the sealing element 96 is properly held in position without any risk of being moved during time.

The sealing element 96 performs several functions; (a) supporting the tray, (b) preventing squeezing of the tray, (c) preventing the tray from touching metal, and, (d) providing flexibility during soldering of the sealing film 43 to the tray.

A knife receiving groove 100, having a closed form, extends peripherally between the tray receiving shoulder 94 and a bracket top surface 102. Two gas inlet holes 104, located at a first side 106 of the knife receiving groove 100, open into the knife receiving groove 100 and the bracket top surface 102. Three gas outlet holes 108 open into the knife receiving groove 100, at a second side 110 of the knife receiving groove 100 that is opposite the first side 106 of the knife receiving groove 100.

A gas valve operating switch 112 protrudes upwardly from the bracket top surface 102. When the gas valve operating switch 112 is pressed, it mechanically operates a mechanical valve (not shown) that releases a compressed gas, from a gas container/reservoir outside the apparatus 10, for replacing the atmosphere within the tray as will be later described. Typically, the compressed gas is fed to the apparatus 10 through rigid/flexible piping, from a conventional compressed gas container/cylinder that is located adjacent the apparatus 10. However, there are facilities having a bulk reservoir of a compressed gas or a compressed gas generator. In this case, the compressed 10 gas may be fed directly, through rigid/flexible piping, to the apparatus 10.

The upper arm 14 comprises a pressing, soldering, and cutting mechanism 114, as can be best seen in Figs. 14-17, that, for sake of convenience, will hereinafter be called the "PSC mechanism".

The upper arm 14 comprises a base plate 116 that forms a rigid part with the upper arm 14. The PSC mechanism 114 comprises a pressing plate 118 that is hanging from the base plate 116 by means of hanging bolts 120 constituting pressing plate hanging members. Typically, four hanging bolts 120 are used, however, any other number of hanging bolts may be used according to design needs. The pressing plate 118 has a size and a shape that are in conformity with the size and the shape of the tray receiving bracket 86. A pressing gasket 122 is attached to a lower portion of the pressing plate 118. The pressing gasket 122 is relatively flexible and typically is made of silicon, however, other gasket materials may be chosen provided that they enable adequate sealing and flexibility.

Each hanging bolt 120 freely passes through a bolt aperture 124, formed in the base plate 116 (marked in Fig. 15 but not specifically shown). An upper end of each of the hanging bolts 120 is provided with a stroke limiting nut 126 that is larger than the bolt aperture 124 and cannot pass therethrough. A downwardly urging spring 128 is assembled on each of the hanging bolts' 120, between the base plate 116 and the pressing plate 118. The downwardly urging spring 128 has a diameter that is larger than the bolt aperture 124 and, therefore, cannot pass therethrough.

According to the described above, it may be appreciated by a person skilled in the art that the pressing plate 118 is "floating" with respect to the base plate 116, i.e., the distance between the pressing plate 118 and the base plate 116 may very during various steps of operation of the apparatus 10.

A soldering platform 130, having a soldering lip 132 in a lower portion thereof, is attached to the base plate 116 by means of soldering platform hanging members. A heating element 134 is installed within a heating element groove 136 formed in an upper portion of the soldering platform 130. The soldering platform 130 is attached to the base plate 116 in a similar manner (not specifically shown) as the pressing plate 118 is attached to the base plate 116. Therefore, also the soldering platform 130 is "floating" with respect to the base plate 116, i.e., the distance between the soldering platform 130 and the base plate 116 may vary during various steps of operation of the apparatus 10.

A knife 138 is surrounding the soldering platform 130, slightly distanced away therefrom, The knife 138 is in a form of a peripherally closed thin metal sheet. An upper portion of the knife 138 is bounded by a knife base 140 that is rigidly connected to the base plate 116. A lower portion of the knife 138 is toothed. Typically, each knife tooth (not specifically shown) is flat, in an inward direction of the knife 138, i.e., toward the adjacent portion of the soldering platform 130, and, is beveled ground in an outward direction of the knife 138, i.e., toward the adjacent portion of the pressing plate 118.

Reference will now be made to Figs. 18 and 19 for describing a tray removing mechanism 142. For sake of clarity, a tray 144 is hand marked in the figures. The tray 144 comprises a tray body 146, having a tray bottom 148, and a tray wall 150 rising upwardly from the tray bottom 148. A tray shoulder 152 extends peripherally outwardly from an upper portion of the tray wall 150. A lower portion of the tray shoulder 152 constitutes a support surface 154 on which the tray 144 lies on the sealing element 96 of the tray receiving shoulder 94. An upper portion of the tray shoulder 152 constitutes a soldered surface 156 on which the sealing film 43 is being soldered.

During previous stages of operation, i.e., during pressing, soldering and cutting, the tray 144 is positioned within the tray receiving aperture 92, and the support surface 154 of the tray shoulder 152 firmly lays on the sealing element 96. When it is desired to remove the tray 144 after the film is being soldered thereto, as will be later described, a tray removing handle 158 is being pressed.

The tray removing handle 158 is connected to a handle shaft 160 at a first end of the handle shaft 160. A second end of the handle shaft 160 is connected to a lever support arm 162. A lifting lever 164 is connected to the lever support arm 162 at an end of the lever support arm that is remote from the handle shaft 160. According to some embodiments, the lifting lever 164 is connected to a lever support arm 162 at both ends thereof. In this case, one lever support arm 162 is connected to a handle shaft 160 that is connected to the left side bracket 28, and another lever support arm 162 is connected to a handle shaft 160 that is connected to the right side bracket 26. However, if desired, the lifting lever 164 may be operated by a single lever support arm 162.

Reference will now be made to Figs. 1, 3-5 and 20-21 for describing an operating handle 166 of the apparatus 10. For sake of effectiveness and ease of operation, the operating handle 166 extends along the width of the apparatus 10 and is symmetrical with respect to the longitudinal median plane P.

The operating handle 166 comprises a holding portion 168 that extends between two operating frames 170. The two operating frames 170 are connected to a common operating axle 172 that rotates with respect to the upper arm 14. An up rotating spring 174 is connected to the operating axle 172, at a first end thereof, and, to the upper arm 14, at a second end thereof. The up rotating spring 174 urges the holding portion 168 upwardly, as shown by the arrow showing spring urging direction 176 in Fig. 20.

The operating handle 166 is provided with a stroke releasing handle 178 that is connected to the operating frame 170 by a stroke releasing lever 180 at either side of the stroke releasing handle 178. Each stroke releasing lever 180 is rotatable with respect to its corresponding operating frame 170 around a stroke releasing axle 182. In a non-operated position of the stroke releasing handle 178, it is distanced from the holding portion 168 of the operating handle 166 by means of a stroke urging spring 184 that is assembled on the stroke releasing axle 182.

Each stroke releasing lever 180 is provided, in an inward portion thereof, with a protrusion 186. In a non-operated position of the stroke releasing handle 178, the protrusion 186 rests within a looking slot 188 formed in the upper arm 14. The locking slot 188 is larger than the protrusion 186, therefore, the holding portion 168 of the operating handle 166 may be freely pressed downwardly a certain stroke until the protrusion 186 abuts against an end wall of the locking slot 188.

At this stage, in order to release the protrusion 186 from the locking slot 188, the stroke releasing handle 178 is pulled toward the holding portion 168 of the operating handle 166, with the same hand holding the holding portion 168. Thus, and with counter pressure urged by the stroke urging spring 184, the protrusion 186 is retracted from the locking slot 188 and the holding portion 168 of the operating handle 166 may continue its downward movement.

A lower portion of each of the operating frames 170 is provided with a sliding buffer 190 that is made from a relatively soft and rigid material such as PVC, plastic, or the like. The sliding buffer 190 comprises, in a forward portion thereof, a flat slanted surface 192. A sliding surface 194 extends rearwardly from the slanted surface 192 and ends with a sliding limiting wall 196. The lower frame 12 is provided with a pressure support rod 198 that is connected between the right side bracket 26 and the left side bracket 28, and is located adjacent the slanted surface 192 of the sliding buffer 190 prior to operating the stroke releasing handle 178.

When the stroke releasing handle 178 is operated, the operating frames 170 continue their downward movement until the slanted surface 192 of each of the sliding buffers 190 meets the pressure support rod 198. At this stage, the pressure support rod 198 urges the entire upper arm 14 downwardly and the sliding surface 194 gets under the pressure support rod 198.

At this stage, continuing lowering the holding portion 168 of the operating handle 166 assures the downwardly directed pressure by the upper arm 14, since the distance between the sliding surface 194 and the operating axle 172 is larger adjacent the slanted surface 192 than adjacent the sliding limiting wall 196. Thus, as much as the holding portion 168 is lowered, the downwardly directed pressure applied by the upper arm 14 is increased.

The operation of the apparatus 10 will now be described. When it is necessary to load the film into the apparatus 10, the sealing film roll 42 is positioned on the support rods 38 between the spacers 40. Then, the upper arm 14 is lifted and remains in an upright position by means of the balancing pistons 16. Now, the bracket secure knobs 80 are pulled outwardly in order to retract the securing pins 82 out of their corresponding pin receiving holes 84. At this stage, the film positioning bracket 78 is not locked to the lower frame 12 and it is lifted upwardly by lifting the front film driving roll 72, typically with one hand.

Now, the film is pulled by the other hand and freely positioned over the tray receiving bracket 86, with a tray 144 positioned therein, and beyond the front film tightening roll 74. At this stage, the film positioning bracket 78 is lowered into a working position and the bracket securing knobs 80 are pulled outwardly and released in order to insert the securing pins 82 into their corresponding pin receiving holes 84, for locking the film positioning bracket 78 in the working position.

When the upper arm 14 is lowered, the rotation of the feeding cam 50 with respect to the main operation axis A operates the entire feeding system 44, i.e., the feeding system rear portion 46 and the feeding system front portion 48.

At the feeding system rear portion 46, the rotation of the feeding gear 52 turns the film driving roll 56 through the feed receiving gear 54, and then, the rotation of the film driving roll 56 rotates the film tightening roll 62 through the mutual rotation in opposite directions of the driving gear 58 and the drive receiving gear 60. Thus, the sealing film 43 that is squeezed between the film driving roll 56 and the tightening rings 66 of the film tightening roll 62 is fed forwardly during the downward movement of the operating handle 166.

Simultaneously, the belt 70, which is driven by the belt driving gear 68, rotates the belt receiving gear 76. Thus, in a similar manner as described above, the front film tightening roll 74 is rotated. However, in contrary to the feeding system rear portion 46 where the film tightening roll 62 is connected to the film driving roll 56 through two gears, i.e., the drive receiving gear 60 and the driving gear 58, correspondingly, the front film driving roll 72 is not connected to the front film tightening roll 74 through two gears. In this case, the front film driving roll 72 is rotated through the pressure applied thereon by the tightening rings 66 of the front film tightening roll 74, when the sealing film 43 passes therebetween. Thus, the sealing film 43, at the feeding system front portion 48, is fed forwardly during the downward movement of the operating handle 166 simultaneously and at the same measure as the forward feeding imposed by the feeding system rear portion 46.

Since the stroke of the operating handle 166 between an open position and a closed position is constant, the constant rotation of the feeding cam 50 causes a constant feeding of the sealing film 43. The sealing film 43 remains straight and stretched due to the even pressure applied thereon by the tightening rings 66 of the film tightening roll 62 against the film driving roll 56, and, by the tightening rings 66 of the front film tightening roll 74 against the front film driving roll 72.

Thus, as explained above, a single motion of the operating handle 166 provides a constant and measured forward feeding of the sealing film 43.

The process of utilizing the apparatus according to the present invention involves the following steps:

1. 1- Film feeding, at a constant measure.
2. 2- Gas insertion.
3. 3- Soldering.
4. 4- Film cutting.
5. 5- Removing the soldered tray.

Thus, upon the end of the first step, i.e., film feeding, the sealing film 43 is stretched over the tray 144. Now, continuation of lowering of the operating handle 166 enables the pressing plate 118, through the pressing gasket 122, to press the gas valve operating switch 112 located on the bracket top surface 102 of the tray receiving bracket 86.

At this stage, the pressing on the gas valve operating switch 112 releases an inert gas, as was described above. The inert gas enters through the gas inlet holes 104, rapidly flows between the tray 144 and the sealing film 43 which is still slightly distanced from the tray 144, and exits through the gas outlet holes 108. The quick flow of the inert gas replaces, partially or entirely, the atmosphere within the filled tray.

Now, continuation of lowering of the operating handle 166 brings the entire pressing plate 118, through the pressing gasket 122 to press the sealing film 43 against the bracket top surface 102. This keeps the sealing film 43 stretched and tight, and without any possibility to move with respect to the tray 144 during the soldering and cutting processes.

Since the pressing plate 118 "floats" with respect to the upper arm 14 due to the assembly of the hanging bolts 120, further lowering of the operating handle 166 brings the soldering lip 132 to press the sealing film 43 against the soldered surface 156 of the tray shoulder 152.

The heating element 134 seated within the heating element groove 136 of the soldering platform 130 is operated through two control switches (located on the upper arm 14 but not specifically shown). A first switch is the main power switch which is turned on while the apparatus 10 is in operation. Typically it is not recommended to switch off the main power switch for short intervals since it takes time to re-heat the heating element 134 after it has being cooled.

A second switch is a thermostat switch which controls the temperature of the heating element 134. The set temperature varies according to the; (1) sealing film 43 material, (2) sealing film 43 thickness, (3) tray shoulder 152 size, (4) tray material, (5) environmental temperature and humidity.Typically, after the satisfactory result has been achieved, i.e., the sealing film 43 has been properly soldered to the tray 144, the same soldering temperature is being used, with slight temperature modifications up or down. Typically, the thermostat switch is calibrated from 60°C to 200°C.

The soldering process continues as long as the operator continues pressing the operating handle 166. According to some embodiments, it is the operator who decides when continuing to the next step, namely, cutting the sealing film 43. However, according to other embodiments, the apparatus 10 is provided with a signaling unit (not specifically shown) that signals the operator when the soldering time has been elapsed and it is possible to continue to the next step, namely, cutting the sealing film 43.

According to some embodiments, the signal is a light signal in the form of a light source that is lit or extinguishes according to need. Thus, e.g., a red bulb is lit when the soldering should be continued, and, a green bulb is lit when the soldering has been finished and it is possible to continue to the cutting stage. According to some embodiments, the signal is an audio signal. In which case, a buzzer sounds when it is possible to continue to the cutting stage. The signal may be defined according to a measured soldered temperature, or, according to a measured soldering time.

At the next step, when the soldering has been finished and it is possible to continue to the cutting stage, the operator pulls the stroke releasing handle 178 toward the holding portion 168 of the operating handle 166, with the same single hand that was used so far, and continues the pressing of the holding portion 168.

At this stage, as was described above, the protrusion 186 of the stroke releasing lever 180 is retracted from the locking slot 188 and the holding portion 168 of the operating handle 166 may continue its downward movement. Since the pressing plate 118 and the soldering platform 130 are both independently "floatable" with respect to the upper arm 14, the downward movement of the operating handle 166 enables the pressing plate 118 and the soldering platform 130 to remain in their current position, i.e., against the bracket top surface 102 and the tray shoulder 152, correspondingly, while the knife 138 moves downwardly.

Thus, the knife 138 protrudes downwardly with respect to the pressing plate 118 and the soldering platform 130, and cuts the stretched sealing film 43 while freely nesting within the knife receiving groove 100 of the tray receiving bracket 86, The cut obtained is neat and clean, follows the perimeter of the tray shoulder 152, and it may be close to the tray 144 as much as required.

As can be seen in Fig. 11, the external contour of the knife receiving groove 100 is not following exactly the contour of the tray receiving shoulder 94, and, at two corners 200 of the knife receiving groove 100 it is more distanced from the tray receiving shoulder 94. Correspondingly, the knife 138 follows the contour of the knife receiving groove 100. Thus, when the knife 138 performs the cutting action, it leaves two film "tongues" at two edges of the tray 144. These "tongues" (not specifically shown) serve as a gripping portion when it is necessary to use the content of the sealed tray by tearing off the soldered sealing film 43.

Finally, in order to remove the sealed tray, the operating handle 166 is lifted upwardly until the upper arm 14 gets to a fully open position as shown in Fig. 4. Then, the tray removing handle 158 is pressed in a releasing direction as shown by the arrow 202 in Fig. 19. This causes the lifting lever 164 to urge upwardly a front end 204 of the tray 144. Now, the sealed tray may be easily grabbed and removed from the tray receiving bracket 86 and a new filled tray 144 may be located within the tray receiving aperture 92 for starting a new cycle of tray wrapping as was described above.

Thus according to the process described above, an inert sealed food tray is obtained, Since there is practically no oxygen within the sealed tray, it enables to substantially increase the shelf life of the product within the tray. According to the described above, the present invention provides a sealed tray having an inert atmosphere within. This is done through a manual operation in a single stroke that may last 2-3 seconds. Namely, the downward movement of the operating handle 166 performs the following steps: (1) sealing film 43 feeding, at a constant measure, (2) gas insertion and atmosphere replacing, (3) soldering of the sealing film 43 against the tray 144, (4) cutting the sealing film 43 around the tray shoulder 152, and, finally, (5) removing the sealed tray by means of the tray removing handle 158.

It should be noted that the. only supply of electrical power to the apparatus 10 is for heating the heating element 134, and all the other operations described above are solely manual.

Although the present invention has been described to a certain degree of particularity, it should be understood that various alterations and modifications could be made without departing from the spirit or scope of the invention as hereinafter claimed.

For example, the tray receiving bracket is not limited to receive only one tray and other tray receiving brackets are fitted to receive a multitude of trays therein.

The material in which the food trays are made of are, and not limited to, polypropylene, polyethylene, polystyrene. The number of the gas inlet holes and the number of gas outlet holes is not limited to the described in the above embodiment and other number of holes may be applied, for example, 1, 2, 3, 4 or more. Furthermore, the holes do not have to be rounded, and narrow slots may be equally applied according to design needs.

The knife teeth do not have to be beveled from one side only and they may be beveled at both sides. Furthermore, if it is desired, the knife may be produced without distinctive teeth. In which case, the lower portion of the knife is made as a continuous and adequately ground cutting edge.

The apparatus is not limited to provide an inert atmosphere to food products only, and it may be used for other kinds of products requiring inert atmosphere for extension of the product shelf life and for oxidation prevention.

These products may consist of pasts, compounds, paints, chemicals or the like.

The knife does not necessarily have to leave two "tongues" of film to serve as a gripping portion, and any other number may be chosen according to specific needs. Furthermore, at some embodiments it is required to leave no gripping tongues.

The bracket seeming knobs 80 may be formed such that they do not have to be pulled outwardly and released in order to insert the securing pins 82 into their corresponding pin receiving holes 84. Alternatively, the securing pins may be formed such, for example, by being rounded, that when the film positioning bracket 78 is lowered into a working position, the securing pins automatically get into their corresponding pin receiving holes 84 thus locking the film positioning bracket 78 in its working position.

The feeding system front portion does not have to be connected to the feeding system rear portion by means of a belt and other engagement members may be used, for example, a chain or the like.