US1709692A - Expansion-joint strip - Google Patents

Description

April 16, 1929. v L, M. SWOPE ET AL- 1,709,692

EXPANSION JOTNT STRIP Filed July 29, 1924 2 Sheets-Sheet l c w ve,

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April 16, 1929, L. M. SWOPE ET AL 1,709,592

EXPANSION JOINT STRIP Filed July 29, 1924 2 Sheets-Sheet 2 Patented Apr. 16, 1929.

LESLIE m. sworn AND some (I. zunaur, OF.NORFOLK, vIaeInm, AssIenoas TO ODENDHAL-MONKS CORPORATION, or NORFOLK, VIRGINIA, a CORPORATION or VIRGINIA.

EXPANSION -J OINT STRIP.

Application filed July 29, 1924. Serial no, 728,901.

Our invention relates to means for providing for the contraction and expanslon-of street pavements, concrete roads'and the llke.

The object of our invention is to provide a marketable board, to be used as an expansion oint strip in pavementconstructions, which couples the greatest degree of expansibility and contractility with board-like rigidity and a non-adhesive'exterior.

Our invention consists in the method of construction, combination and arrangement of parts and in the completed expansion joint board as an article of manufacture.

In the drawings illustrative of our invention: 1

Figure 1 is a perspective view of a portion of our expansion joint board.

Figure 2 is a similar view illustrating the sectional features.

Figure 3 is a perspective view of a modification of our expansion joint board.

Figure 4 is a side view of a portion of our expansion joint board.

Figure 5 is a cross section view on the dotted line ma in Figure 1.

Figure 6 1s a crosssection view of a portion of our expansion joint board when out longitudinally through the center.

Figure 7 is a similar view of the modified board in Figure 3.

Figure 8 is a sectional perspective v ew of a. concrete road with our invention in use.

The expansion joint board constructed ac cording to our invention comprises a body of relatively thick cross-section of asphalt or suitable bituminous material of board-like formation, perforated transversely with a series of holes reinforced on each side by a longitudinal strip of fibre board of sufficient with to cover the holes, and having relatively thin side-surfacing sheets of asbestos.

We prefer to construct theboard asshow'n in Figures 1, 2, 4, 5 and 6, by first laying a sheet of asbestos 3 in size equal to the side of the proposed joint on the bottom of a mould shaped to fit, and upon this. longitudmally through the center of the asbestos a strip of fibre board 2 four inches wide the full length of the mould. Then on top of the fibre board along the center we place oval disks two inches in vertical diameter and six inches apart and with the thickness of the desired expansion board. Asphalt 1 is then poured- 'into the mould and around the disks to the thickness desird and allowed to cool, when the disks are removed, leaving a two inch hole 4.- every six inches apart. Over the series of holes thus made, a second strip of fibre board 2 similar to the first is laid and on the' top of the fibre board is placed a second sheet of asbestos 3 in size equal to thefirst. Pressure is applied by rollers or weights to obtain cohesion of the several parts, thus making a built-up expansion joint board of two sheets of asbestos, two strips of fibre board and a filling of asphalt with a line of two inch holes transversely through the center.

' Our invention is ca able of some modification and variation from the structure as above described, as for instance, other reinforcing materials may be used in conjunction with the vacuum spaces instead of asbestos sheeting, or the asbestos side-sheeting may be saturated with asphaltio compound to Waterproof the same, thus making the boards lessnon-adhesive but retaining the other advantages of plain asbestos sheeting, or again,

the holes may vary in number and size or may be eliminated entirely along with the'supporting fibre board, as in Figures 3 and 7 thus obtaining an asphalt asbestos board of less 'contractility but of greater economy in manufacture. I

Our asbestos, perforated, asphalt board constitutes a practical improvement and novelty over other expansion joints now in use. It is an exceedingly old expedient both to preform elastic joints for pavements and to use asphalt or bituminous material in such joints. A plain asphalt preformed jbint, however, is fundamentally defective, because in cold weather, it is brittle and easily broken, while in hot weather it lacks rigidit and becomes sticky, making handling di fli cult and storage or shipping impossible, since the planks, when piled up, will gum together. This very early suggested the idea of reinforcing such joint strips either internally or externally and of covering'the sides thereof with non-adhesive material, which ideas are now common property by expiration of patent, and therefore we do not claim such combinations broadly. We are also aware that, prior to our invention, asphalt joint strips have been made with external reinforcements and covering, consisting of paper, elastic felt and saturated felt etc., and that Letters Patent have been granted limited to the specific the use of asbestos sheeting in combination with paving joint strips constitutes a distinct novelty.

In the first place, asbestos is a mineral.

whereas canvas, paper, felt and the like, as heretofore used in joint strips, are all made from vegetable and animal matter. It will last indefinitely because it is made of rock,

There-is nothing in it to rot or dry out. In

fact, one of the most valuable properties of this mineral, is vits durability against such "forces of disintegration as heat, cold, fire and moisture. This "rock is ideally suited to paving construction, necessarily more so than vegetable and animal felts etc. Beginning with the manufacture of the joint strip, the molten asphalt partially permeates the asbestos sheeting and the'saturated area be- 7 comes a mineral compound. Then when the board is set and wet cement is poured alongside it, the moisture of the cement loosens the fibres of the remaining asbestos, and the wet cement fills in between the fibres, so that the asbestos fibres becomes a part and parcel of the cement compound. When the cement dries and hardens, there is left a solid mineral joint, less likely to leave a crevice between the pavement and the joint filler for water and other damaging elements to enter. In-

this closed joint there is no foreignmatter to rot or decay under the force of the elements, viz, heat, cold, light and water.

In the second place, asbestos sheeting makes a better finish to the joint strip than eitherfelt, paper or cloth, while possessing reinforcin qualities equal or superior to them,

' thus 0 ering distinct advantages in handling,

storing and shipping. If paper or cloth is used, the molten asphalt poured in the mould or otherwise used in making the joint, will permeate the pores of the paper or cloth and oozing outward, will keep the joint strip more or less sticky in hot weather. Thin canvas likewise; and thick canvas is of prohibitive cost. Felt, if saturated, as the felt commonly used, presents a sticky and gummy surface on the side of the joint strip in hot weather;

and ifnot saturated, will deteriorate and decay quickly in the joint. Molten asphalt and similar bituminousm'aterials do not saturate "through asbestos sheeting, the fibres of-which are interlocking, and therefore the joint strip with asbestos sides is entirelynon-adhesive filler, preserving the filler. from fluidity and" retaining a greater board-like rigidity inthe joint-strip. This,vof course, makes our joint 1 strips superiorto the pliable and gummy rag felt, cloth and paper reinforced stripsin the shipping and storing.

matters of handling, When set up in the joint, moreover, this character tends to a certain extent to retard oozing of the filier out of the joint in hot weather, with its accompanying disadvantages.

Likewise, our use of perforations or a series of holes represents a distinct improvement over otherpreformed joints, all of which are of solid construction. When the latter are installed, they have no spaces for expansion and. in hot weather,,the asphalt filler has a tendency to ooze upward upon the pavement, because this is the only outlet for expansion. As explained-above, this is undesirable. Our invention provides chambers within the joint itself, into which the asphalt filler will tend to expand, thus presenting a joint of superior contractility and minimizing the expansion upward upon the pavement. The central fibre board strips 2 used to cover the holes, as in Figure 2, are necessary to prevent the cement used in adjacent paving from filling the chambers 4.

WVe claim:

1. As an articleof manufacture, an expansion oint strip comprising a body of relatively thick cross-section of'asphalt or suit-- ly thin side-surfacing sheets of asbestos.

2. As an article of manufacture, an expansion joint board comprising a body of asiphalt or-suitable bituminous material, perforated with a series of holes co vered and reinforced by strips of suitable side surfacing material. Y LESLIE M. SWOPE. JOHN C. ZULAUF.

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