US3035825A - Shock absorber - Google Patents

Description

y 1952 J. J. WELLER 3,035,825

snocx ABSORBER Filed Aug. 19, 1960 INVENTOR (/bH/V I M/ELLE 2 Q M ATTORNEY United States Patent Cffice 3,035,825 Patented May 22, 1962 3,035,825 SHOCK ABSORBER John J. Weller, Allentown, Pa., assignor to Standard Plastics, Inc., Fogelsville, Pa., a corporation of Pennsylvania Filed Aug. 19, 196), Ser. No. 50,724 6 Claims. (Cl. 267-1) This invention relates to an article of manufacture, and more particularly to a resilient article suitable for use as a cushioning device or bumper in packages, crates, and the like.

In shipping fragile articles there exists the problem of protecting the article against damage while in transit. The classic, although obsolete, technique for protecting articles in their shipping crates is the stufling of wastepaper, excelsior or rags between the article and the sides of the crate. This technique was never very successful because, among other reasons, it depended on the knowledge of the person preparing the crate to stuff the proper amount of paper or waste between the article and the sides of the crate. If an insuflicient amount of paper were stuffed into the crate, or if the paper were not properly located, the article very often became damaged in transit. Furthermore, such techniques are not adequate for the protection of relatively heavy objects having delicate components.

Eventually the classic technique of using waste-paper as a stufling material was replaced by corrugated cardboard. The corrugated cardboard was cut into suitable sizes for wedging the article within the crate. Corrugated cardboard, however, is subject to crushing. Frequently, therefore, articles which were cushioned by the located cardboard became damaged because the corrugated cardboard became crushed in transit and lost its cushioning ability.

Accordingly, it is a primary object of this invention to provide cushioning means especially suitable for use in boxes, shipping crates, and the like, which is resilient, inexpensive to manufacture and, which is not subject to any of the shortcomings of the conventional cushioning means.

It is a further object of the invention to provide a uniquely shaped, unit-handling cushioning device made of a soft foamed resilient material having the property of breathing.

Another object is to provide a unit-handling cushioning device which will make optimum use of the resilient material thereof, by eifectively eliminating loss of supporting efiiciency at outer limits thereof.

It is a feature of this invention to provide a cushioning device which retains its general shape, under conditions to which such articles are normally subjected.

In accordance with an aspect of the invention the cushioning device comprises a foam-plastic body member having relatively stiff set-in or concave ends to provide aresilient knee-action response to forces applied to the top and bottom of the article. The shape of the article and its end stiffness are obtained by reinforcing means which, in one form, surrounds four sides of the article; in other forms, separate end-reinforcing members are used.

The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description in conjunction with the accompanying drawing. In said drawing, which shows, for illustrative purposes only, preferred forms of the invention:

FIG. 1 is a perspective view of a preferred form of the novel cushion device; and

FIGS. 2 and 3 are fragmentary perspective views of alternative forms of stiffening member in modified cushion devices.

The basic part of the cushioning device is a foamed resilient material, such as foam rubber or plastic which has the property of breathing. A preferred foam-plastic material for use in the invention is a flexible elastovrneric cellular plastic such as polyurethane, sometimes known as urethane foam. By way of interest, cellular products of polyurethane material are formed from liquid polymeric reaction mixtures containing polyisocyanates. The reaction mixtures are polymeric materials which are either liquid at room temperature or capable of being melted at relatively low temperatures. The polymeric materials contain active hydrogen atoms which react with the isocyanate groups to form a network of cross-linked molecular chains. A polyisocyanate functions as a crosslinker or curative for the polymeric material and also reacts with water provided in the liquid reaction mixture to form carbon dioxide, which causes the liquid reaction mixture to expand and foam, whereby a flexible, cellular structure is formed which retains its foamed cellular character after the polymer has been cross-linked or cured.

The foamed character of the material is an essential characteristic which imparts the desired degree of resiliency to the cushion device. Moreover, since the material is foamed it has the property of breathing whereby, once polymerized, the cushion device is not subject to permanent deformation.

Referring now to FIG. 1, the cushion device, as for use in ordinary shipping crates, comprises a reinforced body member 1, preferably made of polyurethane material having the characteristics described above. The preferred shape is generally cubic or rectangular prismatic, having a top side 2, bottom side 3, and end sides 4-5.

The end sides 4-5 of the cushion device are set-in or concaved a predetermined amount from the top and bottom sides 2-3. Preferably, the set-in end sides are in the shape of a V, the angle of the V being approximately The end sides 2-3 are of reinforcing material and have the property of reducing and efiectively eliminating endeifects which result in bulging and loss of support at the ends of unreinforced foam material. This being the case, the overall resilient load capacity for a given size cushion device is increased by the reinforcing end sides of the invention.

Reinforcing the end sides 4-5 may be accomplished in a variety of ways. In the form of FIG. 1, a peripherally continuous cardboard structure comprises the top side 2, end 5, bottom side 3, and end 4, all continuously and effectively integrally joined to each other. The grain or corrugations of the card-board preferably extends in the direction of peripheral continuity, as suggested by shading on parts 2-5. In practice, the basic cardboard shape 2-53-4 is retained between two parallel plates to define the mold for the resilient material while it is expanding and until it has set or polymerized. What were open sides (as at 6) then become exposed generally flat sides of the resilient body 1, and the foam plastic is caused to bond itself to the retaining and reinforcing cardboard.

In use, the cushion device will be placed between two articles to be subjected to shock, as for example between a crate inner wall and an object to be protectively supported within the crate. Generally, several such cushions will be used to support various sides of the object within the crate. As to any particular cushion, the top surface 2 may be secured to or rest against the crate wall, and the opposite surface may be secured to or rest against the object. A preloaded resilient support action is achieved if the crate is designed to squeeze the cushion against the object.

In the presence of squeezing preload, or in the presence of shock producing a squeezing action on the cushion, any tendency of the foam material to bulge at the ends 45 is not only resisted by the reinforcement provided by cardboard at 45, but the stiffness of the legs 78 at end 5 and the foam-cardboard adhesion in shear (at 12 and at 13) impose articulation at folds 11-1213 (at end 5), While the stifiness of legs 9-10 at end 4 and the same adhesion in shear impose articulation at the corresponding folds between parts 2-9--103 at end 4. This articulation effectively converts the end reinforcing members or legs 78 and 9-10 into pistons working against each other to increase the loading pressure on the resilient body -1, to a level well in excess of that attributable solely to normal forces on surfaces 2-3. As a result, a given body of resilient material is caused to perform a more efiicient job of both steady and transient load support.

As indicated, in *FIG. 1 the reinforcing material extends peripherally of body 1, and articulation at corners such as 11-13 depends upon adhesion of 'body 1 to surfaces 23. The main point is that corners, as at 11, shall not spread or displace outward-1y in the presence of compression. Continuity of top and bottom members 2-3 positively assures tension in these members, to avoid such spread.

Although the reinforcement material has been described as cardboard, it will be understood that other materials such as sheet metal, e.g., aluminum or steel sheet may also serve the purpose. Also, the reinforcement may be a composite of materials, as for example, cardboard at 7--8 and 10, secured to each other by strips or by a continuous belt of lnraft paper, in which case the top and bottom surfaces would be paper, preferably including a fibrous or woven reinforcement to Withstand tension.

In FIGS. 2 and 3, I show modifications in which separate end reinforcement members are employed. In FIG. 2, end member 5 generally resembles the fully exposed end of FIG. 1, and it comprises legs 7'8' and top and bottom flanges 1415 bonded to one end of a resilient body, suggested at 1. Member 5 may be of cardboard, metal, or the like, as long as the desired articulation can be achieved with relative freedom at 1112'13, as will be understood.

In the form of FIG. 3, the end member 5" is smoothly concaved, as of arcuate form at 16, with top and bottom flanges 17-18'. When bonded to body 1", and in the presence of top-bottom compression, the are 16 deforms somewhat uniformly to create a more distributed inward lateral additional compression on the ends of body 1". If corrugated cardboard is used in FIG. 3 for reinforcement member 5', then the corrugations preferably run at right angles to the direction indicated in FIG. 1, thus assuring'uniform bending throughout the are 16.

It will be seen that I have described an improved cushioning device wherein the reinforcement combines with the resilieent material to produce a result exceeding the sum attributable/to the parts alone. By my knee-action reinforcement, the resilient body delivers optimized performance.

While the invention has been described in detail for the preferred forms illustrated, it will be understood that modifications may be made within the scope of the invention as defined in the claims which follow.

I claim:

1. A cushion device, or the like, comprising a foamed resilient body having top, bottom and opposed end sides, the opposed end sides being set-in a given amount from the top and bottom sides, and snrface-stiffening means carried at said opposite end sides and conforming to the set-in contour of said ends, said stiffening means comprising corrugated cardboard, the stiff direction of the corrugations extending from end-to-end and from top-to-bottom along the opposite end sides.

2. The device according to claim 1, wherein said corrugated cardboard stiffening means encompasses said top, bottom and end sides, the cardboard being coextensive with said sides and bonded thereto.

3. The device according to claim 1, wherein said setin end sides are V shaped.

4. A cushion device, or the like, comprising a foamed homogeneous resilient body having top, bottom front, rear and opposite end sides, each of said end sides being set-in a given amount from the top and bottom sides, and surface stiffening means conforming to the setin contour of said ends and extending from said top side to said bottom side and bearing against said opposite end sides, respectively, the front and rear sides being substantially free of said stiffening means, said stiffening means serving to maintain the shape of said device.

5. The device according to claim 4, in which said set-in end sides are arcnate.

. 6. The device according to claim 4, wherein said stiffening means includes sheet metal.

References Cited in the file of this patent

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