Apparatus For Forming And Stacking Container Lids

Abstract

The present invention relates generally to improvements in apparatus for forming relatively shallow container lids and the like and more particularly to apparatus for (i.e., production of such lids from heated plastic sheet material. The present application discloses apparatus for feeding a web of heated plastic sheet material to a forming station. The forming station comprises a mold cavity positioned above the heated sheet material, and a plunger means beneath the sheet material. Relative movement between the mold cavity and plunger means causes a shallow container lid or the like to be formed and sheared from the sheet stock. Means superimposing the plunger means is provided for successively receiving completely formed lids and positioning them in stacked relation.

Description

SUMMARY OF THE INVENTION

It is an important object of the present invention to provide novel and practical apparatus whereby methods may be practiced to produce relatively shallow container lids and the like from a web of heated plastic sheet material and to position such container lids in stacked relation.

More specifically, the present invention contemplates a very simple and unique arrangement whereby relatively shallow container lids may be formed and thereafter successively advanced to form a vertical stack.

Still more specifically, the present invention contemplates a novel and highly efficient plunger mechanism for practicing the above-mentioned method.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects and advantages will be more apparent from the following detailed description when considered in connection with the accompanying drawing wherein:

FIG. 1 is a side elevational view of a machine equipped with the novel shallow container lid forming mechanism of the type contemplated by the present invention;

FIG. 2 is an enlarged fragmentary vertical sectional view taken centrally of one of the mold cavities and complementary plunger mechanisms, said plunger mechanism being shown in its lowermost position, before moving upwardly into association with a heated sheet of plastic material;

FIG. 3 is a fragmentary plan view of the upper portion of the lid forming structure, more clearly to illustrate the arrangement of the lid receiving and stacking rods;

FIG. 4 is a view similar to FIG. 2 showing the plunger mechanism moved upwardly into initial engagement with the heated sheet of plastic material within the mold cavity;

FIG. 5 is a view similar to FIG. 4, disclosing the manner in which continued forward or upward movement of the plunger mechanism severs a completed lid from the plastic sheet material prior to the advancement of the completed lid into the stacking station; and,

FIG. 6 is a view similar to FIGS. 4 and 5 disclosing the manner in which the central section of the novel plunger mechanism successively forces completed lids upwardly into the stacking station.

DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

Referring now to the drawings more in detail wherein like numerals have been employed to designate similar parts throughout the various figures it will be seen that one embodiment of a machine or apparatus of the type contemplated by the present invention is designated generally by the numeral 10. For a clear understanding of the present invention, a detailed description of the apparatus 10 is not deemed necessary. It will suffice therefore to point out that the apparatus 10 includes a base 12, the right extremity of which supports a bracket 14 for accommodating a shaft or mandrel 16. The shaft 16 carries a roll of suitable sheet thermoplastic material 18. A web of the sheet material 18 is moved to the left (FIG. 1) through a suitable electric heating unit 20. From the heating unit, or station 20, the sheet 18 is fed into a lid forming and stacking mechanism or station 22. From the station 22 the sheet material is directed to a take-up shaft 24. The take-up shaft 24 may be intermittently rotated through the agency of a drive belt 26 driven from an electric motor 28.

The forming and stacking mechanism 22, includes a platen 30 mounted on vertically reciprocable guide posts 32. Vertical reciprocation is imparted to the bed 30 by means of a rotatable cam member 34 which engages a depending section 30a of the platen 30. The cam 34 is driven from a suitable electric motor 36. The upper portion of the mechanism 22 includes a stationary platen or frame 38. The plastic web moves intermittently from right to left as viewed in FIG. 1. During each dwell of the web the platen 30 moves upwardly through the agency of the cam 34, thereby simultaneously moving a plurality of adjacently positioned plunger mechanisms 40, FIG. 2, toward the underside of the plastic web 18. The web 18 which had been previously heat treated at the station 20 is now in a softened or plastic condition.

The plunger mechanism 40 consists of an inner plunger or ejector member 42 provided with a shallow recess 44 and companion plunger member 46 secured to the upper side of the platen 30. When the plunger member 42 occupies the position shown in FIG. 2, it is seated within a recess on the upper side of the plunger member 46. Hence, as the platen 30 moves upwardly from the position shown in FIG. 2, the combined plunger members 42 and 46 moved upwardly as a unit.

The underside of the plastic web 18 is initially engaged by upwardly projecting annular plunger sections or ribs 50 and 52 of the plungers 42 and 46 respectively, FIG. 4. At this period in the cycle of operation the space beneath the web 18 is evacuated through the agency of a suitable pump 54, FIG. 1, which communicates with a shallow recess 56 the upper extremity of the plunger 42 through a central passageway 58 extending longitudinally within a depending section 60 of the plunger member 42. This evacuation causes the plastic sheet to be formed as shown in FIG. 4. The combined annular sections or ribs 50, and 52, cause the plastic sheet to be formed into an annular bead 62. The bead 62 encompasses a flat central disc-like portion 64. The bead 62 and the portion 64 combine to form a shallow recessed lid designated generally by the numeral 66.

As the combined plunger members 44 and 46 continue their upward movement, the plunger member 46 cooperating with an annular die member 49 causes the bead 62 to be sheared from the web 18, FIG. 5. The plunger member 46 has now reached the limit of its upward stroke and the plunger 42 continues further upward travel to the position shown in FIG. 6. This upward movement of the plunger 42 relative to the plunger member 46 results from the engagement of a cam section 34a, with a member 68 connected with a vertically shiftable plate 70, FIGS. 1 and 2. This plate 70 simultaneously engages the lower extremities of each of the depending sections 60 of the plunger members 42. During this movement the outer margin of the bead 62 is sprung past an annular abutment or shoulder 72 positioned along the inner periphery of the annular die member 49. This annular die member 49 is secured in any suitable manner to the underside of the fixed platen 38 and presents a female mold cavity 74 for successively receiving completely formed lids 66. These lids are ultimately shifted upwardly in stacked relation above the platen 38. Rods 76 projecting upwardly from and supported by the platen 38 serve as guides for the lids 66 as they are moved upwardly successively in stacked relation.

As previously mentioned the platen 30 carries a plurality of adjacently positioned plunger mechanisms 40, each of which comprise a pair of the plunger members 42 and 46. Likewise the upper platen carries a plurality of adjacently positioned die members 49 each of which is disposed in alignment with a complementary plunger mechanism 40. Similarly the platen 38 supports a plurality of groups of guide rods 76, each group being complementary to one of the annular die members 49.

From the foregoing it will be apparent that the present invention contemplates a very unique and practical method whereby relatively shallow container lids may be formed from a web of plastic material and contemporaneously arranged in stacked relation to facilitate subsequent ease of handling. When the lids have been stacked to a predetermined height within each group of three guide rods they may be removed in mass by simply lifting them out of association with the rods. Applicants novel plunger mechanism and associated annular die cavity are of relative simple and practical construction. The structurally novel plunger mechanism comprised of the plunger member 46, and the plunger member 42 which is shiftable as a unit with, and also relative to the plunger member 46 makes it possible to successively form, shear and contemporaneously shift completely formed lids into stacked relation.

Claims

I claim:

1. Apparatus for forming and stacking relatively shallow container lids and the like from heated plastic sheet material comprising means for supporting a sheet of such material in plastic condition, a female mold cavity means positioned immediately above a supported sheet, plunger means disposed on the underside of a supported sheet in alignment with said female mold cavity, said mold cavity and the upper portions of said plunger means cooperatively defining a relatively shallow container lid, means for shearing a completely formed lid from said plastic sheet stock, and means superimposing said mold cavity means for successively receiving completely formed lids as an incident to the upward movement of said plunger means and positioning them in stacked relation.

2. Apparatus for forming and stacking relatively shallow container lids and the like as set forth in claim 1, wherein the upper portion of the plunger means is provided with a shallow recess for accommodating sheet material.

3. Apparatus for forming and stacking relatively shallow container lids and the like as set forth in claim 1, wherein means is provided for establishing a pressure differential between the upper extremity of the plunger means and said mold cavity means.

4. Apparatus for forming and stacking relatively shallow container lids and the like as set forth in claim 1, wherein the plunger means is comprised of at least two plunger members, one being relatively shiftable with respect to the other.

5. Apparatus for forming and stacking relatively shallow container lids and the like as set forth in claim 1, wherein the inner margin of the mold cavity means is cooperatively disclosed with respect to the outer margin of said plunger means for shearing a completely formed lid from the sheet material.

6. Apparatus for forming and stacking relatively shallow container lids and the like as set forth in claim 1, wherein the plunger means includes an inner plunger member shiftable within and respect to a second plunger member for ejecting a completed container lid from the mold cavity means.

7. Apparatus for forming and stacking relatively shallow container lids and the like as set forth in claim 1, wherein said plunger means is provided with a passageway connectable with means for establishing pressure differential on opposite sides of a supported sheet whereby to form a relatively shallow recess in said sheet.

8. Apparatus for forming and stacking relatively shallow container lids and the like as set forth in claim 1, wherein the plunger means consists of at least two plunger members, one being longitudinally shiftable within and respect to the other, and having a passageway connectable with means for establishing a pressure differential on opposite sides of a supported sheet.

9. Apparatus for forming and stacking relatively shallow container lids and the like as set forth in claim 1, wherein the plunger means comprises a pair of plunger members, one being shiftable with respect to the other, and also moveable as a unit therewith, said members when combined, presenting an annular bead forming rib for engaging the underside of a supported plastic sheet.

10. Apparatus for forming and stacking relatively shallow container lids and the like as set forth in claim 1, wherein the mold cavity means comprises an annular member having a substantially vertical axis, and shoulder means projecting inwardly from the inner surface of said annular member.

11. Apparatus for forming and stacking relatively shallow container lids and the like as set forth in claim 1, wherein the mold cavity means is stationary an the plunger means is longitudinally shiftable into and out of association with said mold cavity means.

12. Apparatus for forming and stacking relatively shallow container lids and the like from heated plastic sheet material comprising means for supporting a sheet of such material in a substantially horizontal position, a female mold cavity means having a vertically disposed cylindrical opening therethrough, said female mold cavity means fixedly mounted with said cylindrical opening extending vertically upwardly immediately above said sheet supporting means, vertically reciprocable plunger means in vertical alignment with said cylindrical opening, the upper side of said plunger means and the lower portion of said female mold cavity means cooperatively disposed to define a shallow container lid when said plunger means occupies a predetermined vertically disposed position, said plunger means and the lower portion of said female mold cavity means further cooperatively disposed for shearing a formed lid from a heated section of sheet material associated therewith, and means for shifting said plunger vertically upwardly to shift a previously formed lid upwardly into lid stacking position within said cylindrical opening.

13. Apparatus for forming and stacking relatively shallow container lids and the like as set forth in claim 12 wherein an annular projection extends radially inwardly from the wall defining said cylindrical opening above the lid forming cavity adjacent the upper face of said plunger means.