Blank Wrapping Mechanism And Method For Frusto-conical Cup-making Machines

Abstract

A machine for making two-piece paper cups including individually actuated folding wings for wrapping the blank around a frusto-conical mandrel. The wings are actuated by cams which swing the folding wings rapidly through the initial wrapping phase without applying any appreciable clamping pressure, and then apply a final squeezing action to the blank against the mandrel just prior to the sealing of its longitudinal seam. A method of wrapping a blank around a mandrel with a fast initial wrapping action followed by a final squeezing of the blank tightly against the mandrel.

Description

BACKGROUND OF THE INVENTION

This invention pertains to machines for making two-piece paper cups of the type having a frusto-conical shape and a flat, separate bottom. More particularly, the invention pertains to improved actuating means for actuating the swinging wings for wrapping the paper blank around the mandrel where the overlapped edges of the blank are then sealed together.

The invention is in the nature of an improvement over the mechanism for operating the folding wings shown in my U. S. Pat. No. 2,942,530 issued June 28, 1960 and entitled "Blank Wrapping Mechanism for Frusto-Conical Cup-Making Machines".

SUMMARY OF THE INVENTION

The present invention provides a blank wrapping machine and method for forming a tow-piece, flat bottom cup and includes a pair of individually operated folding wings which are swung from an open blank-receiving position to a closed position in which the blank is fully wrapped around the mandrel and the overlapped seams are then sealed together. Means are provided for actuating the folding wings in timed sequence, which means includes an individual cam for each wing, the timing of which is such that the wings are swung through their initial blank-wrapping movement without applying any appreciable clamping pressure to the blank against the mandrel, and then at the end of this initial wrapping operation, the wings apply a final squeezing, pressure clamping action against the blank to firmly wrap the blank around the mandrel and just prior to the sealing of the overlapping longitudinal edges of the blank.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a portion of a two-piece cup-making machine embodying the present invention, the folding wings being shown in the open, blank-receiving position, and the blank being indicated by a broken line.

FIG. 2 is a fragmentary perspective view of the device as shown in FIG. 1, but with the folding wings in an intermediate position just prior to the application of the final squeezing operation, no blank being shown in this view;

FIG. 3 is a vertical view taken generally along the line 3--3 in FIG. 1 certain parts being shown in section or broken away;

FIG. 4 is a fragmentary view of the portion of the device shown in FIG. 3 but showing the wings in an intermediate position in which the blank has been wrapped around the majority of the mandrel but prior to overlapping of the longitudinal edges;

FIG. 5 is a view similar to FIG. 4 but showing the blank being further wrapped around the mandrel as when the final squeezing is being applied and just prior to the seam clamp coming down to seal the longitudinal edges;

FIG. 6 is a view similar to FIG. 3 but showing the folding wings in the fully clamped position and the seam clamp in the sealing position;

FIG. 7 is an elevational view of one of the gears for one of the wings and showing the various portions of the cam track; and

FIG. 8 is an enlarged side view of the folding wings and mandrel shown in FIG. 6 with parts shown in section.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The two-piece cup-making machine closed for the purposes of illustrating the present invention includes a rotatable table 10 having a plurality of blank gripper means 11 spaced around its periphery for holding the body blanks B and transferring them from the blank cutting and blank glue-applying stations (not shown) to the srapping station illustrated in FIG. 1. A rotatable turret 13 carries a plurality of tapered mandrels 14, 15 and 16, among others, around its periphery, which mandrels have vacuum passages 17 for for holding the circular cup bottoms E on the end of the mandrel.

As the structure and function of the mandrels and the gripper means are fully described in my said U.S. Pat. No. 2,942,530, further reference to them is not believed to be necessary nor desirable. It is also believed sufficient to say that a seal clamp 20 is mounted above each of the mandrels and is adapted to be lowered at the appropriate time to bear against the glued and overlapped longitudinal edges of the blank to thus seal them togther.

A pair of folding wings 22 and 23 are pivotally mounted about the common center shaft 24 and in themselves are conventional.

The center shaft 24 is vertically shiftable by the vertically shiftable rod 25 which is activated by the lever 25a pivoted at 25b. Lever 25a is actuated by a means (not shown). Rod 25 causes the entire wing assembly to shift bodily between a lower position away from the mandrel (FIG. 3) to an upper position (FIG. 6) adjacent the mandrel.

The wings are swingable between the lowermost position shown in FIG. 3 and the uppermost wrapping position shown in FIG. 6, by means of their respective compound links 26 and 27, respectively, which are vertically shiftable and guided in the bushings 28 and 29 fixed in the table 30 of the machine. The lower ends of these compound arms are pivotally attached to their respective levers 31 and 32 which, in turn, are pivotally mounted at one end to a shaft 33 and 34 carried by the table 30. Each of the levers 31 and 32 have a cam follower 36 and 37, respectively, intermediate their length. A separate cam 40, 41 is provided, respectively, for each of the cam followers 36 and 37. More specifically, the cam tracks 42 and 43 are formed in the side of the cam members 40 and 41 and these tracks are continuous and of the shape shown in detail in FIG. 7. The cam members 40 and 41 have teeth around their periphery which are in constant mesh and, consequently, in time with one another. One of the cams is driven by its shaft 45 from the power source not shown.

Referring in greater detail to FIG. 7, the cam track portion 50 is formed to cause the actuating arms of the wings to initially rise until the point 52 on the cam is reached. This rising movement is relatively fast and quickly raises the arms from the position shown in FIG. 3 to the position shown approximately in FIG. 5. In the FIG. 5 position, the wings do not yet apply any appreciable pressure on the blank against the mandrel.

The machine shown in my U.S. Pat. No. 2,942,530 was and is capable of producing approximately 130 cups per minute. The production on that particular machine was limited by the violent slapping action of the wings against the mandrel during the last portion of the wrapping function. This created considerable noise and wear on the machine parts which restricted increased production rates.

In accordance with the present invention and as shown in portion of the cam from radial line 52 to 53 is formed so that the wings apply a final, firm but gentle squeezing pressure around the blank and mandrel during the last wrapping phase and that squeezing phase is shown as occurring in FIG. 5. The cam than has a dwell portion between radial lines 53 and 54 during which time the longitudinal edges of the blank are overlapped and the seam clamp 20 descends to effect a seal. In other words, during the sealing operation, the cam is formed so as to provide a dwell period during which the sealing of the joint is completed.

The arcuate portion of the cam from line 54 to 55 is provided to cause the wings to all again to their original position shown in FIG. 3. A dwell portion of the cam is then provided between lateral lines 55 and 56 in FIG. 7 before the next folding operation commences.

RESUME

By means of the present invention, a two-piece paper cup-making machine is provided having individually actuated folding wings, each of which is actuated by a separate cam. The cams provide for a fast initial swinging movement of the folding wings to substantially complete the wrapping operation, but without applying any appreciable pressure against the blank and mandrel. Immediately thereafter, the cams provide for a final squeezing operation of the blank tightly against the mandrel.

With this timed movement and two distinct phases of wrapping, the slapping and violent action of the wings against the mandrel during the final stage have been eliminated. This invention has substantially reduced the noise and wear on the various parts and greatly increased the production rate of the improved cup-making machine.

Claims

I claim

1. A high speed two-piece paper cup-making machine comprising, tapered mandrel, a pair of wrapping wings for shaping the body blank around the mandrel, said wings being mounted on a common shaft which is located centrally beneath said mandrel, each of said wings being of one piece construction, one of said wings operating in advance of the other to overlap the longitudinal edges of the blank; means for operaring said wings and comprising a rotatable cam member for each of said wings, each of said cam members having gear teeth around their periphery, the teeth one cam member meshing with the teeth of the other cam member for providing timed relationship between said cam members, each of said rotatable cam member having a cam track therein, said cam tracks each having a rise portion for causing an intitial fast wrapping action of said wings so as to cause said blank to be wrapped around said mandrel without any appreciable clamping pressure, said cam tra ks each also having a subsequent mandrel squeezing portion for them causing said wings to apply a final squeezing action to said blank round said mandrel, and linkage means for each cam member and including a cam follower engageable in its respective cam track and connecting each of said cam members with its respective wing.