Rope handle forming machine and method

The rope handle forming machine is made of a cylinder having a channel therein, an U-shaped forming plate mounted along a horizontal plane tangent to the top surface of the cylinder on one side of the cylinder, and a D-shaped forming plate mounted in a same plane as the U-shaped forming plate on the other side of the cylinder, facing the U-shaped forming plate. A rope feeder is provided along the horizontal axis of the cylinder to feed a rope stock into the channel. A cutoff blade is used to severe a rope length from the rope stock. A push-up blade mounted in the channel moves upward when the cylinder rotates and the channel reaches a twelve o'clock position, to raise the rope length above the mentioned plane. The forming plates are movable toward each other along the plane to retain and form the rope length into an U-shaped form.

FIELD OF THE INVENTION

This invention pertains to apparatus for making twisted paper or rope handles for shopping bags, and more particularly it pertains to apparatus for measuring, severing and forming an U-shaped rope handle, and for attaching the formed handle to a patch which is suitable for gluing to a bag web.

BACKGROUND OF THE INVENTION

A rope-handle shopping bag is made by attaching an U-shaped rope length to a patch made of heavier material than the bag web. The patch is then glued or hot melted to the bag web. The two sides of the bag web are then formed so that the positions of the handles are matched on each side of the bag. Rope handles are mostly made of twisted paper and are most often attached to bags made of paper, although plastic materials are also used for both the handles and the bag webs.

In the last decade or so, the plastic bag industry has been through difficult times because of the ecological concerns generated by the final disposal of plastic products in general. Many countries around the world are banning the use of plastics and reverting to paper for manufacturing packaging products. Environmental management systems such as ISO 14,000™ have been introduced to industries across the world in an effort to better control the growth of our landfill sites and the reduction of greenhouse and ozone layer depleting gases emanating from these sites. In numerous instances during the introduction of these new standards, paper has been cited as being a preferred material of manufacture for packaging products, because paper is recyclable and is harmlessly biodegradable, and therefore it is environmentally friendly.

Research conducted in the retail market has shown that shoppers have a preference for paper when it comes to handled shopping bags. Although paper grocery bag usage in North America is in the decline, no such decline has been seen in the use of paper in speciality shopping bags. It is believed that the market demand for paper shopping bags will be maintained or will improved in the future.

Rope handle forming machines currently available are extremely large and complicated. Some are integrated into large bag making machine, which are not practical for rapid change in sizes and to meet the needs of manufacturers who do small runs of various sizes at slower speeds. Also, because of the high cost and complexity of machinery currently available to manufacturers of shopping bags, much of this work has gone to third world countries where the work is done by hand.

Although the devices and apparatus of the prior art deserve undeniable merits, it is believed that a market demand still exists for a rope handle making machine that can lower the cost of manufacture of handled shopping bags through lower investment in the machine; higher productivity through faster speeds and less maintenance due to the simplicity of the design. It is believed that a market demand still exists for a rope handle forming machine that can be incorporated into traditional rotary cutoff bag formation machines to easily convert them to shopping bag manufacturing machines.

SUMMARY OF THE INVENTION

The rope handle forming machine according to the present invention can be used to manufacture twisted U-shaped handles made of paper, rope or plastic strings and to attach these handles to paper or plastic patches either by gluing or hot melt welding processes. The rope handle forming machine can be operated in a stand alone mode to manufacture rope handles for later attachment to shopping bags manufactured elsewhere, or can be incorporated into a bag manufacturing process. Preferably the rope handle forming machine is incorporated as a module in an existing production line between the roll stand that hold the bag material and the bag forming machine. If a printing press is utilized, the rope handle forming machine according to the present invention can be placed between the printing press and the bag forming machine.

Another advantage of the rope handle forming machine according to the present invention is that the rope handles formed thereon require less materials for the patch than traditional machines since the handles do not require patches on both sides of the rope lengths.

When the rope handle forming machine is incorporated into a bag manufacturing process, a pair of these machines are preferably utilized to cut, form and attach a pair of rope handles onto a pair of patches that are then glued or hot melted onto both sides of a bag web simultaneously. The bag is then formed and sent to a stacking or packaging station.

In a broad aspect of the present invention, there is provided a process for forming a rope handle comprising the steps of providing a cylinder having a channel there along; providing a U-shaped forming plate movable along a plane tangent to a surface of the cylinder; providing a D-shaped forming plate movable along the plane mentioned above and into the U-shaped forming plate. The method also comprises the steps of feeding a rope stock into the channel; cutting the rope stock into a rope length; raising the rope length outside the channel and exposing the rope length above a surface of the cylinder along the mentioned plane, between the U-shaped forming plate and the D-shaped forming plate. Then the D-shaped forming plate and the U-shaped forming plate are moved into mutual engagement, thereby pulling a central segment of the rope length therein and forming an U-shaped handle with the rope length. The U-shaped handle is then moved over a patch handle and attached to the patch handle.

In another aspect of the present invention, the process of forming a rope handle comprises the additional step of forming creases in the patch material and encasing the straight segments of the U-shaped handle into these creases.

In yet another aspect of the present invention, there is provided a rope handle forming machine, comprising a cylinder having a channel therein and a horizontal axis of rotation; an U-shaped forming plate mounted along a plane tangent to the surface of the cylinder on one side of the cylinder. The U-shaped forming plate has a U-shaped opening therein and an open end facing the cylinder. The rope forming machine also has a D-shaped forming plate mounted in a same plane as the U-shaped forming plate at a distance from said U-shaped forming plate on the other side of the cylinder, facing the open side of the U-shaped forming plate. A rope feeder is provided along the horizontal axis of the cylinder to feed a rope stock into the channel. A push-up blade is mounted inside the channel and moves upward when the cylinder rotates and the channel reaches a twelve o'clock position relative to the horizontal axis. The push-up blade moves upward to raise the rope length above the cylinder's surface and into the plane of the forming plates.

The forming plates are movable toward each other to retain and form the rope length into an U-shaped form. A pair of pinch rolls are provided to move the rope length in an U-shaped form from the forming plates to a vacuum roll. The vacuum roll a has a vacuum pad thereon for retaining a handle patch. A press roll rotates against the vacuum roll to assist a gluing or a hot melt welding process in attaching the rope length in an U-shaped form to the handle patch.

DESCRIPTION OF THE PREFERRED EMBODIMENT

While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will be described in details herein one specific embodiment, with the understanding that the present disclosure is to be considered as an example of the principles of the invention and is not intended to limit the invention to the embodiment illustrated and described.

The rope handle forming machine according to the preferred embodiment is illustrated herein in a schematic manner for clarity. Many components of this rope handle forming machine are not illustrated to facilitate the understanding of the basic principles of this apparatus. The components that were not illustrated are those for which the natures, mountings and functions would be obvious to the persons skilled in the art of Machine Design in general.

The rope handle forming machine according to the preferred embodiment is also described in term of its operation and the function of its components. The physical dimensions, material type and manufacturing tolerances of the individual parts are not provided herein because these details also do not constitute the essence of the present invention and are considered obvious to the skilled artisan.

Referring firstly toFIG. 1, the rope stock20is fed from a spool22of rope material through a rope feed pulley24located in the lower part of the rope handle forming machine. The rope stock20is wound around the feed pulley24to provide maximum pull from the rope spool22and prevent slippage. This feed pulley24is synchronized in rotation to match the machine's speed. The rope stock20is fed through the rope feeder assembly26, which pushes the rope stock into the main cylinder's inlet cone28and into the rope channel30along the main cylinder32.

The main cylinder32is supported on both ends thereof in a pair of block bearings (not shown). The block bearings engage with the cylindrical surfaces shown by labels34and36. The bearing surface36in particular is further defined in FIG.4. This drawing also illustrates a cross-section of the inlet cone28and of the rope guide38there through wherein the rope material20is fed from the centre of the inlet cone28along the axis of the main cylinder32to the rope channel30at the circumference of the main cylinder32.

The main cylinder32is driven by a ring gear40as shown inFIGS. 1 and 2which is also synchronized in rotation to run in sequence with the other components of the rope handle forming machine as will be understood though the following description. With each rotation of the ring gear40, a rope length20′ is cut by means of a rope cutoff knife blade42, mounted to a knife holder44, as illustrated in FIG.5.

Immediately after the rope stock20has been severed to the proper length by the knife blade42, the rope feeder assembly26pulls back ¾″ or so to leave space for the cutoff knife blade42to travel past the rope channel30. When the rope length20′ is being formed, the rope feeder assembly26moves back to feed another length of rope stock20into the rope channel30. The back and forth movements of the rope feeder assembly26along the axis of the main cylinder32is better effected by an air cylinder (not shown) located under the machine, although other arrangements can also be used.

As the main cylinder32rotates and brings the rope channel30at the twelve o'clock position46, a rope push-up blade50located inside the main cylinder32pushes the cut rope length20′ from the rope channel30to a position clear above the surface of the main cylinder32and above the machine's table which is illustrated by the horizontal plane52inFIGS. 1-3and5. The plane52which represents the top surface of the machine's table extends tangent to the top surface of the main cylinder32.

For reference purposes, the rope channel30is shown at a ten o'clock position in FIG.5. The push-up blade50is also illustrated in FIG.5. The push-up blade50is activated radially by two lifter cams54. These cams54are mounted on a stationary shaft56along the axis of the main cylinder32. The main cylinder32rotates around this stationary shaft56in the direction of the arrow58. Both cams54are spaced apart along the stationary shaft56a distance of about half the length of the main cylinder32.

The push-up blade50is held between the sides60of the rope channel30. The push-up blade50extends substantially the full length of the rope channel30. The push-up blade50is urged toward the stationary shaft56by means of spring pairs62attached to the transverse pins64which are affixed to the push-up blade50and to the transverse pins66affixed to anchor blocks68protruding from the inside surface of the main cylinder32. At least two spring pairs62are preferably used to retain the push-up blade50to the bottom of the rope channel30during a major sector of rotation of the main cylinder32. The locations of the spring pairs62alternate with or are otherwise adjacently positioned from the cams54along the main cylinder32. The sides60of the rope channel30have transverse slots therein (not shown) to allow a radial movement of the transverse pins64relative to the main cylinder.

The position of the knife blade42relative to the axis of the main cylinder32is slightly ahead of the twelve o'clock angle46, as illustrated inFIG. 5such that the rope stock20gets severed entirely by the knife blade42before the rope channel30reaches this uppermost position. During the cutting of the rope stock20, the portions of the rope stock on both sides of the knife blade42are preferably retained inside the channel30. Such retention of the rope stock20is effected by the rope guide38on one side of the knife blade42and a ring70mounted over the end of the main cylinder32, under the knife holder44.

The cams54have lobes72at the twelve o'clock angle of the stationary shaft56. Consequently, as the main cylinder32rotates, the push-up blade30reaches the lobes72, and is urged upward by the lobes72, thereby pushing the rope length20′ out of the rope channel30to the a region immediately above the plane52.

As the push-up blade50reaches its uppermost position, it exposes the rope length20′ above the main cylinder32. An outer U-shaped forming plate80mounted along the plane52, as illustrated inFIG. 1moves in a downstream direction82toward the raised rope length20′ and pushes the rope length20′ against an inner D-shaped forming plate84as illustrated in FIG.2. During the motion of the outer U-shaped forming plate80, the inner D-shaped forming plate84may also be moved toward the outer forming plate80to swiftly move the rope length20′, and especially to more easily align the ends of the rope length20′ in the downstream direction82. These movements of the outer and inner forming plates80,84cause the central segment of the rope length20′ to be caught between the forming plates80,84, giving it an U-shaped form and leaving the rope ends extending freely beyond both plates.

Then, the outer forming plate80and the inner forming plate84move in unison in the downstream direction82to carry the U-shaped rope length20′ to the handle transfer rolls, or pinch rolls86. As the pinch rolls86grab the free ends of the rope length20′, the tip88of the inner forming plate84is tilted momentarily downward, as shown inFIG. 3, by an actuator90moving against a cam or otherwise (not shown) to release the central segment of the rope length20′, thereby allowing the rope length20′ to move freely toward the vacuum cylinder92.

A roll of patch material (not shown) may be mounted downstream of the rope handle forming machine according to the preferred embodiment. The patch material is fed through the top of the rope handle forming machine over rollers, feed rolls, and through a rotary cutoff knife which is timed to cut each patch to the desired width (not shown). As the patch is cut off, it is transferred by a known process to the vacuum roll92where it is held by vacuum over a grooved pad94.

Glue is applied to the patch96along two strips which coincide with two grooves98in the vacuum pad94and with the alignments of the straight segments100of the rope length20′.

The rotation of the pinch rolls86and of the vacuum roll92are synchronized to overlap the straight segments100of the rope length20′ over the handle patch96, in alignment with the grooves98of the grooved pad94. A press roll102is mounted below the vacuum roll92and rolls against the vacuum roll92to force the straight segments100of the U-shaped rope length20′ into the grooves98, thereby deforming the patch material into the grooves94and forming creases in the patch material, in which the straight segments100are encased. The pressing of the straight segments100in the creases causes the strips of glue to spread around the straight segments100and to the patch96.

It will be appreciated that this encasing and gluing actions of the rope length20′ to the patch96provides a strong bond. The finished bag handle102can then be bonded to a bag web by a known glue or hot melt welding process. In this handle, portions of the straight segments100of the rope length20′ are exposed on their side opposite the creases for gluing to the bag web. These portions are later glued or hot melted to the bag web, thereby providing a stronger bond of the rope handle104to the shopping bag.

As to other manner of usage and operation of the present invention, the same should be apparent from the above description and accompanying drawings, and accordingly further discussion relative to the manner of usage and operation of the invention would be considered repetitious and is not provided.

While one embodiment of the present invention has been illustrated and described herein above, it will be appreciated by those skilled in the art that various modifications, alternate constructions and equivalents may be employed without departing from the true spirit and scope of the invention. Therefore, the above description and the illustrations should not be construed as limiting the scope of the invention which is defined by the appended claims.