Method Of Reinforcing A Plastic Bar

Abstract

A method of reinforcing a plastic bar member to strengthen it against bending forces comprising the steps of providing a rigid strip of metal reinforcing having a width W and a thickness T; forming a groove in said plastic of a depth greater than W and a width substantially equal to T; positioning said metal reinforcing member in said groove; placing a thin strip of plastic over the exposed position of said metal reinforcing member and applying beads of molten plastic over said strip to bond to said thin strip and each side of the groove by melting and solidifying in sequence.

Parent Case Text

This is a divisional application of application Ser. No. 91,394, filed Nov. 20, 1970, entitled IMPROVED HANGER BRACKET AND DRIVING APPARATUS FOR PLATING BARRELS, now Pat. No. 3,668,103, issued Jun 6, 1972.

Description

To the extent necessary for an understanding of the invention, the background to this invention as described in the above-identified co-pending divisional application, is incorporated herein by reference.

FIG. 1 is a fragmentary elevational view of an electroplating barrel and its associated gears and hanger bracket, illustrating one use of the reinforced bars of this invention.

FIG. 2 is a side elevational view taken along line 2--2 of FIG. 1.

FIG. 3 is a sectional view taken along line 3--3 of FIG. 1.

FIG. 4 is a sectional view taken along line 4--4 of FIG. 1.

FIG. 5 is an enlarged sectional view taken along line 5--5 of FIG. 1.

This invention is concerned with strengthening a plastic bar against bending and by way of illustration, the invention is shown in the drawings as being a part of a plastic barrel used in electroplating, phosphating or the like. The environment shown will be described briefly.

The barrel 28 is supported from the channel member 29 by two pairs of hangers 41, each having upwardly extending arms 42 and 44. The arms 42 and 44 are adjustably joined to the channel by short angle members 46 and 48 respectively [See FIG. 1]. Each of the angles 46 and 48 is welded to a lateral face of the channel 29 and has elongated bolt receiving slots 47 and 49 formed therein. Suitable machine screws pass through the slots into engagement with the respective hanger arms. By releasing the screws, the vertical position of the hangers 41 can be readily adjusted.

As best shown in FIGS. 1, the hangers extend vertically downward from the channel 29 and support the drum within the electrolyte solution. The construction of the hangers is of particular importance to the invention. As can be appreciated, because of the corrosive nature of the electrolyte or cleaning solutions used, the hangers, as well as the remaining elements of the drum assembly, must be capable of withstanding a particularly corrosive atmosphere. Further, the hangers must have suitable strength to resist the forces exerted thereon during operation and use of the assembly. In the subject embodiment, the hanger arms 42 and 44 are formed from a corrosion resistant plastic such as polypropylene with an internal reinforcing bar of steel or other suitable metal. FIG. 5 is a cross-section through one of the arms or bars 44 showing the internal reinforcing member 50 which is, in this instance, a flat steel bar. The construction of each of the hanger arms 42 and 44 is identical and, accordingly, only one will be described in detail.

Referring again to FIG. 5, it will be seen that the arm 44 is formed from a rectangular, elongated section of polypropylene provided with a longitudinally extending slot 52 which is of a width sufficient to closely receive the metal bar 50, said bar having a width W and a thickness T . The slot 52 extends into the main body of polypropylene a depth greater than the width W of bar 50. Positioned over the outer edge of the bar and within the slot 52 is a strip 54 of plastic or similar material having heat insulating properties. The strip 54 preferably extends throughout the length of the bar 50 and is of a thickness sufficient to provide a groove inwardly from the outer edge of the slot 52. A second strip of plastic 56 is welded to the main block over the strip 54. The welding is accomplished by a conventional plastic welding gun which extrudes a strip of heated plastic into the groove for bonding with the side walls of the groove and the insert 54. Insert 54 serves to prevent the metal reinforcing bar from acting as a heat sink and conducting heat away from the heated weld strip. Without strip 54, the weld bead 56 will deposit in the slot against the bar 50 without bonding to either side wall. This layered arrangement assures a good fluid tight weld joint between the strip 56 and the main body of the block. Thus, the metal reinforcing strip is totally encased in the plastic and is not exposed to the corrosive environment.

The purpose of the encapsulated steel bars 50 is to strengthen the arms 42, 44 in shear, bending and torsion. The plastic if of sufficient strength in tension to carry the load in the drum but without the steel bars the arms fail rather quickly due to the bending moments resulting from the drum rotation and the sway imparted by the tumbling parts therein.

In addition to reinforcing the hanger rods 41, the transversely extending rods or bars 70 are also reinforced with steel strips 51 (see FIG. 1).

To the extent needed for a complete understanding of this invention, the applicant's co-pending application identified above is incorporated by reference.

Claims

What is claimed is:

1. A method of reinforcing a plastic bar member to strengthen it against bending forces comprising the steps of providing a rigid strip of metal reinforcing having a width W and a thickness T;

forming a groove in said plastic of a depth greater than W and a width substantially equal to T;

positioning said metal reinforcing member in said groove;

placing a thin strip of plastic over the exposed portion of said metal reinforcing member and applying beads of molten plastic over said strip to bond to said thin strip and each side of the groove by melting and solidifying in sequence.

2. The method as defined in claim 1 wherein said plastic is polypropylene.

3. The method as defined in claim 1 wherein the plastic bar is of a length greater than its width or thickness,

forming the groove such that it extends along the full length of the bar,

the length of said metal reinforcing member being less than the length of the bar,

placing the thin strip of plastic into the groove such that it covers the full length of the metal reinforcing member as well as its ends.

4. The method as defined in claim 3 including applying the beads of molten plastic over said strip to seal the metal reinforcing member within the plastic bar, said seal being fluid tight.

5. The method as defined in claim 4 wherein the metal reinforcing member is steel and the plastic bar, strip and bead are polypropylene.

6. The method as defined in claim 1 including applying the beads of molten plastic over said strip to seal the metal reinforcing member within the plastic bar, said seal being fluid tight.

7. The method as defined in claim 6 wherein the metal reinforcing member is steel and the plastic bar, strip and bead are polypropylene.

8. The method as defined in claim 1 wherein the metal reinforcing member is steel and the plastic bar, strip and bead are polypropylene.

9. The method as defined in claim 3 wherein the metal reinforcing member is steel and the plastic bar, strip and bead are polypropylene.

10. The method as defined in claim 4 wherein said plastic is polypropylene.