US2053900A - Road joint apparatus - Google Patents

Description

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ROAD JOINT APPARATUS Filed Jan. 29, 1935 4 Sheets-Sheet 4 INVENTORS Patented Sept. 8, 1936 2 UNITED STATES PATENT OFFICE ROAD JOINT APPARATUS Pennsylvania Application January 29, 1935, Serial No. 3,908

7 Claims.

Our invention relates to the forming of joint slots and the installing of joint material in con crete roads and the like, and also includes an improved method for installing dowel bars which ex- 5 tend across or through such slots or joints, with the ends of the bars embedded in the adjacent concrete slabs.

One object of our invention is to provide an improved manner of placing dividing plates or bars at the locations where slots or joints are to be formed, so that after the concrete has been poured, a screed and a smoothing device can be moved over the concrete, without interference by the said plates.

Another object of our invention is to provide an improved manner of supporting dowel bars at desired locations in the concrete, and without the necessity of employing chairs or other supporting members therefor, which ordinarily remain in the concrete and constitute so much loss of metal.

Another object of our invention is to provide a supporting device for dowel bars of such strength that the bars will be held against displacement by dumping of the concrete or by finishing operations on the concrete.

A further object of our invention is to provide an improved manner for supporting dowel bars in their correct positions, independently of the sub-grade.

Still another object of our invention is to provide a generally simplified, improved, and economical manner of installing road joints and dowel bars.

Various forms of apparatus for practising our invention are shown in the accompanying drawings wherein Figure 1 is a plan view of jointinstalling apparatus; Fig. 2 is a longitudinal sectional view of the structure of Fig. 1, in elevation; Fig. 3 is a view, on an enlarged scale, taken on the line IIIIII of Fig. 2; Fig. 4 is a view similar to Fig. 3, but showing the concrete poured, and certain of the parts removed; Fig. 5 illustrates the position of the parts ready for edging or rounding the corners of the concrete slabs at the joint; Fig. 6 shows the completed joint; Fig. '7 is an enlarged view taken on the line VII-VII of Fig. 1, and showing the manner in which the dowel bar supporting elements are employed; Fig. 8 is a view taken on the line VIIL-VIIE of Fig. '7; Fig. 3 shows a modified form of dowel-supporting element in side elevation; Fig. 10 is an edge view thereof; Fig. 11 shows still another modification of the structure of Fig. '7; Fig. 12 is an edge view thereof Fig. 13 shows an arrangement whereby a part-depth joint may be formed; Fig. 14 is a plan view of the structure of Fig. 13; Fig. 15 is a view taken on the line XVXV of Fig. 13; Fig. 16 is a face view showing the manner in which dowel bars of a special type may be supported for imbedment in concrete; Fig. 1'7 is a plan view of a portion of the structure of Fig. 16, on an enlarged scale; Fig. 18 is a view taken on the line XVIII- XVIII of Fig. 1'7; Fig. 19 is a view taken on the line 10 XIX-XIX of Fig. 1'7; Fig. 20 shows the joint of Fig. 19 completed, with the temporary members removed; Fig. 21 shows a modification of the arrangement disclosed in Fig. 19; Fig. 22 is a view: showing the joint of Fig. 21 completed; Fig. 23 is a face view of a transverse joint, looking in the direction of the arrows XXIIIXX'III of Fig. Fig. 24 is a view taken on the line XXIV-XXIV of Fig. 23, and Fig. 25 is a plan view of the struc- 20 ture of Fig. 23.

Referring first to'Figs. 1 to 8, we show apparatus for installing expansion joints and dowel bars transversely of a concrete roadway, but it will be understood that various features of the invention,

are capable also of being employed in the form of 5 guides 25 welded or riveted thereto. The guides 26 serve to prevent tilting of the shield or form plate 27, which may suitably be of sheet metal of the form shown more clearly in Fig. 5.

When a pre-formed joint strip or slab 28 of asphalt or the like is to be placed in the concrete, it is inserted in the shield plate 21, before placing the plate in the guides 26. The lower edges of the plate 21 are cut away to form openings 29 of generally triangular form to receive dowel bars 3|, said bars also extending through holes provided in the asphalt slab 28.

The dowel bars are held against tipping or canting by yokes 32, which straddle the form plate 21, and have hooked engagement with the dowel bars, at opposite sides of the plate The plate 27 has depressions 33 in its upper edge that are inclined at their ends so as to produce a camming effect on the yokes when they are being installed, it being understood that when the yokes are slid into engagement with the dowel bars, the bars will be drawn snugly to their seats at the upper ends of the openings 29. The inclined walls also facilitate removal of the yokes from the concrete, since when they are driven back out of engagement with the dowels, they will tilt somewhat.

When the parts have been assembled as shown in Figs. 1 to 3, the concrete will be poured, causing imbedment of not only the dowel bars 3|, but also the plates 21 and yokes 32. These parts can be assembled in unitary relation, at the side of the roadway, and then placed between the side forms. In some cases, reinforcement mesh 34 will be inserted during the pouring of the concrete. The plate 2! and slab 28 rest upon the sub-grade, and the plate 21 is of such vertical dimension that its upper edge will be perhaps /2 inch below the plane at the surface where the concrete is finished. The yokes 32 are also disposed below the finishing plane, as shown more clearly in Fig. 4.

After the concrete has been poured, the brackets 25 with their guides 26 may be lifted out, so as to permit smoothing machines or other smoothing devices to be freely moved along the side forms 24. The surfacing of the concrete will commonly be effected by first moving a screed or strike-off bar along the side forms to distribute the concrete evenly and bring it to approximately the desired level. This operation will be followed by using finishing belts or other suitable smoothing devices. This screeding and smoothing of the concrete will not be interfered with by the jointforming members.

During the operations of dumping, screeding and finishing the concrete, the dowel bars 3| are firmly held against tilting or angular displacement, by the yokes 32, and this constitutes an important feature of our invention, since it is necessary that the dowel bars be imbedded throughout their lengths at a given depth below the surface of the concrete, and it is also important that they be not angularly displaced in a horizontal plane.

After the finishing operation, the hooks 32 are moved to release them from the dowel bars 3|, and lifted clear of the concrete. Holes 35 may be provided in the upper ends of the yokes for engagement with hooks by which the yokes are lifted from the concrete. The plate 21 is then lifted to approximately the position shown in Fig. 5, by hooks inserted at the ends of the plate, and while the concrete is suificiently plastic, edging tools will be applied, to smooth and finish the corners of the slots at the sides of the plate 21. The plate 21 may be permitted to remain at the position shown in Fig. 5 for some considerable period of time, or until the concrete has become stiff enough to permit removal of the plate without damaging the surface of the concrete. The channel of the plate 21 preferably tapers in somewhat at its lower edge, as shown in Fig. 5, so that it can be more easily removed from the concrete, and with less likelihood of breaking the concrete near the surface of the slabs, during removal of the plate. After removal of the plate, the joint will have substantially t.1e appearance shown in Fig. 6, the plate 21 being of sufficiently thin metal that the concrete can settle somewhat against the sides of the joint strip 28, without cracking.

Each of the dowel bars preferably will have one of its ends covered by a small metal cap or tube 36 which projects somewhat beyond the end of the bar, to provide some clearance space, as shown more clearly in Fig. 1. The remaining portion of the bar at that side of the plate is coated with oil or some other material that will prevent adherence of the concrete to the bar. At the opposite side of the plate 27, the bars need not be coated or covered, but can be permitted to engage directly with the concrete. One end of each bar will therefore have slidable engagement with a concrete slab, so that the slabs may have some movement toward and from each other under changes in temperature or the like, without causing breaking or rupture such as might occur if both ends of each bar were bound tightly in the concrete.

Referring now to Figs. 9 and 10, we show a structure wherein various of the parts may be substantially of the form shown in Figs. 1 to 8. However, in this structure, we show a different form of yoke 3! for use with a plate 38 of channel form, with the upper edge of the plate being straight throughout its length, instead of having depressions formed therein. The yoke 3'! is provided with a slot 39 in each leg, the slots being inclined at their lower edges, so that when the yokes are slid into the position shown in Fig. 9, the dowel bars will be drawn upward firmly to their seats, by a camming action. In this structure, as in Fig. '7, the yokes are removed by sliding them back from the dowel bars, and then lifting them from the concrete.

In Figs. 11 and 12, still another form of yoke is shown. This yoke M is pivotally connected to the form plate 42 and is cut away somewhat at its upper edge to permit swinging movement of the yoke. The legs of the yoke have inclined slots to form hook portions and camming surfaces for engagement with the dowel bars, as in Fig. 9. It will be apparent that the yoke can be merely swung on its pivot into and out of engagement with the dowel bars. It will be understood that the form plates and slabs of Figs. 1 to 12 can be supported in a suitable manner somewhat above the sub-grade, so as to form part-depth joints. Also, the channel form plate can be employed without the necessity of also using an asphalt joint strip. The form plate could be inserted in the concrete substantially as shown, but with the joint strip omitted.

However, it will ordinarily be desirable to provide spacer blocks or strips in the channel to prevent squeezing in of the lower edge thereof by the pressure of the concrete. In order to prevent entry of concrete to the interior of the channel plate, small triangular plates can be inserted in the openings 29, which plates, after removal of the channel plate, can be fished out of the slot by the use of hooks. The slot can then be filled with liquid filling material.

In Figs. 13 to 15, I show a manner in which a part-depth or so-called dummy" joint may be installed. In this structure, a form strip or plate 45 which may suitably be of laminated construction, as shown more clearly in Fig. 15, is supported from the sub-grade on suitable legs 46, and is provided with notches in its lower edges that form seats for dowel bars 41. The plate 45 is suitably supported in guides at its ends, and carries yokes 48, substantially as in the case of the plate 21, and its associated parts, although, of course, yokes of the forms shown in Figs. 9 and 11 can be employed, if desired.

In this case as in the other figures, the concrete is poured and finished over the form plate 45, and the yokes 48, whereupon the yokes are removed and the plate 45 raised to facilitate finishing of the corners of the slabs, and finally removed en tirely, after which filling material may be inserted into the slot, thus formed.

Referring now to Figs. 16 to 20, I show a form plate 55 that may be supported in the same manner as the plate 21, but not requiring recesses in its lower edge. In the arrangement here shown, the dowel bars are of such form that they do not extend through the plate and the joint strip.

The dowel bars 52 have leg portions 53 and footed portions 54. The footed portions may be pressed slightly into the sub-grade, and plates 55 placed thereon in order to prevent the concrete from engaging against the end of the feet 54. If the extremities of the feet 54 were permitted to be imbedded in the concrete, horizontal pressure of the concrete against the same during expansion of the slabs would tend to cause breaking or cracking of the concrete. The plates 55 may be of sheet metal or other light material, that will crumple or be deformed through shifting of the concrete slabs. The rear edges of the plates are bent upwardly to form an angle so that they will be held in position by the plate when the form and dowel bars are assembled.

The dowel bars 52 are placed at each side of the plate 5|, and are engaged by yokes 56 which straddle the plate-5|. One leg 51 of each yoke may be in the form of asingle prong, while the other leg 58 of the yoke is bifurcated, so as to straddle the dowel bar with which the leg 58 makes engagement.

The leg 57 will lie flat against the plate 5 I, while the yoke leg 58 will engage snugly against the vertical face of the dowel bar leg 53, to hold said leg in snug engagement with the side of the plate 5!, and maintain it against tilting away from the plate. The bifurcations in the leg will prevent shifting of the dowel bar in directions longi-- tudinally of the plate 5|. The dowels and the plate may be assembled in unitary relation at the side of the roadway and springs 52a, having their ends hooked over oppositely-extending dowels, utilized to hold the parts assembled while placing them on the sub-grade. The springs will be removed before pouring the concrete.

The concrete can be poured and finished over the yokes 55 and the plate 5|, as heretofore explained, and thereafter the yoke and the plates will be removed. Openings 59 are formed in the upper edge of the plate 5| to permit the insertion of hooks between the yokes. The finished joint with the asphalt strip in place will have substantially the appearance shown in Fig. 20. Handles 50 are provided on the brackets 50a, to permit of more convenient removal of said brackets, preliminary to the pouring of the concrete.

As each dowel bar is imbedded in one of the slabs and has its foot extending beneath the other slab, any raising force on a slab will be transmitted through the dowel foot to the underside of the other slab, and thus the slabs will be maintained in the same plane. Similarly, the dowel feet prevent either slab settling relative to the other slab.

Referring now to Figs. 21 and 22, we show a joint structure formed substantially as in Figs. 16 to 20, but wherein a solid form 6! is substituted for the asphalt strip of Figs. 5 and 20. This may be a wood or a metal form, or wood covered or faced with metal 62. In this arrangement, the form 5| will be removed, leaving an open slot, which slot can be filled by pouring hot asphalt or inserting other suitable material 63 into it.

In those instances where the dividing plate is employed simply to form a slot, a joint strip can be placed in the slot, with its upper edge protruding. Thereafter, the corners of the slabs can be smoothed alongside the strip. The strip can then be pushed farther into the slot or theupper edge thereof flattened down along the joint line.

Referring now to Figs. 23 to 25, we show an arrangement whereby dividing plates 66 and 61 may be mounted in end-to-end relation, where a joint of greater length than a single dividing plate is required. The plates may be mounted between side forms as in Fig. 1, with their inner ends meeting at a point mid-way between the side forms.

A temporary supporting plate 68 of sheet metal or other suitable form has pairs of angles 69 and secured thereto by riveting or welding. The plates 66 and 61 are held in alignment by said angles, and the plate 68 is supported against shifting on the sub-grade or road bed, by pins H. After the concrete is poured and finished, the plates 56, 61 and 68 and the pins 'H' can be removed, although in some cases we may prefer to remove only the plates 66 and 61, allowing the plate 68 and the pins 79 to remain imbedded in and covered by the concrete.

The various forms or dividing plates and dowels can be assembled as a unit alongside the roadway, and can set between the side forms, as needed. By some systems of road building, the concrete mixer will be moved along the sub-grade between the side forms, and has to be periodically stopped while dividing plates and dowels are assembled on the sub-grade between the forms. By assembling the dividing plates and dowels at a point removed from the roadway or sub-grade, they can be made ready for placing in position without materially interrupting the advancing movement of the concrete mixer or paving machine. The boom of the machine, from which the concrete is deposited extends rearwardly of the machine, and the dividing plates and dowels as constructed by us can be conveniently placed on the sub-grade beneath the boom in position to be imbedded by the concrete as the paving machine advances.

We claim as our invention:-

1. Apparatus for forming pavement joints, comprising a form plate having openings through which dowel bars may extend transversely of the plane of the plate, and yoke members straddling the upper portion of the said plate and supported thereby, and having hook elements on their depending legs, for engaging the dowel bars and holding them against tilting, the yoke members being supported on the upper edge of the plate, for movement thereon independently of one another.

2. Apparatus for forming pavement joints, comprising a form plate having openings through which dowel bars may extend transversely of the plane of the plate, a yoke straddling the plate adjacent to each opening and having hook portions for engaging the underside of each dowel bar at each side of the plate, the yokes being mounted for movement longitudinally of the plate and independently of one another.

3. Apparatus for forming pavement joints, comprising a form plate having openings through which dowel bars may extend transversely of the plane of the plate, a yoke straddling the plate adjacent to each opening and having hook portions for engaging the underside of each dowel bar at each side of the plate, each yoke being slidably supported on the upper edge of the plate for movement longitudinally of the plate,

and the plate having depressions in its upper edge that serve as seats for the yokes.

4. Apparatus for forming joints in concrete pavements, comprising a form plate having openings thcrethrough for the reception of dowel bars, means carried by the plate in a plane below the plane at which the concrete is to be surfaced for supporting the dowel bars, the said means being movable on the plate to engage and release the dowel bars. and camming devices operative during dowel-engaging movement of said means for exerting an upward thrust on those portions of the dowel bars at each side of the plate.

5. Apparatus for forming pavement joints, comprising a form plate having openings through which dowel bars may extend transversely of the plane of the plate, a yoke straddling the plate adjacent to each opening and having hook portions for engaging the underside of each dowel bar at each side of the plate, the yokes being movable independently of one another, and camming means for causing the said hook portions to exert an upward thrust on those portions of the dowel at each side of the plate, when the hooks are moved into dowel-engaging position.

6. The combination with side forms employed in making concrete pavements, of a form plate extending laterally of and between said forms, with its upper edge in a plane adjacent to the upper edges of the side forms, and means carried by an upper portion of the plate and movable relative thereto, for supporting dowel bars, the said means being disposed entirely below a plane that is not higher than the upper edges of said forms and plate, and extending downwardly alongside the plate, whereby the surface of the concrete may be finished by moving smoothing elements across the upper edges of the said forms and plate.

7. The combination with side forms employed in making concrete pavements, of a form plate extending laterally of and between said forms, with its upper edge in a plane adjacent to the upper edges of the side forms, and means carried by an upper portion of the plate and movable longitudinally thereof, for supporting dowel bars, the said means being disposed entirely be low a plane that is not higher than the upper edges of said side forms and plate, and extending downwardly alongside the plate, whereby the surface of the concrete may be finished by moving smoothing elements across the upper edges of the said forms and plate.

WALTER S. EDGE. OSCAR F. ARTHUR.

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