US2207168A - Dowel bar joint assembly - Google Patents

Description

July 9, 1940- L. c. THOMAS ET AL 2,207,168

DOWEL BAR JOINTSSEMBLY Filed May 24, 1939 2 Sheet-S-Sheeb 2 l.. Y f l LUKE C. THOMAS ROBERT R. RoERTso/v Patented July 9, 1940 UNITEDA sTATEs PATENT A OFFICE DOWEL BAR JOINT ASSEMBLY Luke C. Thomas, Birmingham, Ala., and Robert It. Robertson, Chicago, Ill.

Application May 24, 1939, Serial No. 275,386

8 Claims. (Cl. 94-8) I'he .present invention pertains to concrete road constructions, and more particularly to contraction and expansion joints of the dowel bar type,

` in which the dowel bars are assembled and arranged to be heldin proper spaced retionship with respect to one another in an assembled joint unit adapted to be positioned on the sub-grade transversely of a road bed, permitting the dowel bars to extend into adjacent road slabs across the -joint in proper relationship with a pre-molded joint strip.

` It is an object of this invention to provide an improved and simplified form of road. joint assembly including properly positioned supports for permanently holding a plurality of dowel bars in spaced parallel relationship with respect to one another for embedding in concrete road slabs.

Another object of this invention is to provide a spacing assembly for dowel bar road joints, of either the contraction or expansion type, and to provide apertured base strips having improved unitary dowel-bar holders secured thereon in proper predetermined spaced relation for permitting the mounting of joint dowel bars in a definite assembly to extend beneath or through road joint filler strips positioned between the road slabs in which the dowel bar assembly is finally embedded.

A further object of-this invention is the provision of an improved and simplified form of continuous spacing assembly for holding a series of spaced dowel bars in proper position, allowing the complete dowel bar 'assembly to be mounted on a road sub-'grade transversely of the road for the entire length of the joint.

It is a furtherobject of this invention to provide an improved and simplified form of continuous spacing assembly for joint ldowel bars, wherein the ends of the bars are engaged in unitary inverted V-shaped holders or brackets, the

feet of which are provided with clamping lugs which project through apertures in spaced spacer plates which are clamped by the respective lugs for definitely holding the dowel bars in proper spaced parallel relation to form a complete joint unit adapted to be placed as a whole upon a road sub-grade transversely of the roadprior to the pouring of concrete to form'the road slabs.

It is also an object of this invention to provide a dowel bar spacing assembly' for use in forming contraction and expansion `joints in concrete roads including improved dowel bar supports-including lug members having projections adapted to be inserted through selectivelyspaced openings in spacer plates which extend throughout the length of the joint and are on opposite sides thereof. l

It is furthermore an important object of this invention to provide an' improved and simplified type of dowel bar spacing assembly for use in the 6 construction of contraction or expansion joints in concrete roads, said assembly including spaced joint length spacer plates having apertures therein at predetermined locations for the reception of the feet or base ends of adjustable or split type dowel bar supporting brackets which are longitudinally placed on the spacer plates to permit the opposite'ends of the dowel bars to be seated in oppositely positioned brackets on opposite spacer plates to form an assembled dowel bar unit 15 for placement as a whole transversely on a road sub-grade between the center joint and the outer edge of the road so that the dowel bars will project across the joint and be embedded in the y road slabs which embed the joint unit. 20

Other and further important objects of -this invention will be apparent from the disclosures Lr; the specification and the accompanying draw- The invention (in preferred forms) is illustrated in the drawings and hereinafter more fully described.

0in the drawings:

Figure 1 is a fragmentary side elevation of the dowel bar construction joint assembly embodying the principles of this invention;

Figure 2 is an enlarged fragmentary top plan view of a portion of the assembly shown in Figure 1, illustrating the positioning and the supporting of the dowel bars;

Figure 3 is an enlarged fragmentary detailed section through the joint portion of a concrete road in which the 'dowel bar assembly is embedded, part of the concrete being omitted to show one of the dowel bars and the supports therefor in elevation;

Figure 4 is a fragmentary side elevation of a modified form of the invention illustrating' an expansion joint dowel bar assembly using modified base strips and a modified pre-molded ller through which the dowel bars project;

.Figure 5 is an enlarged fragmentary section across an expansion joint with portions of the concrete omitted to expose one of the dowel bars and the supports therefor.

Figure 6 is a fragmentary detailed section taken on the line VI-VI of Figure 3, with the concrete omitted, showing the detailed .construction of one of the dowel 'bar brackets or supports;

Figure j 7 is a fragmentary detailed section taken on the line VII- VII of Figure 6.

As shown on the drawings:

The present invention relates to an improved continuous dowel bar spacing assembly for concrete road joints of either the contraction or the expansion type, which spacing assembly is adapted to be placed as a unit transversely across a road sub-grade where a joint is to be located. The dowel bar assembly is of a continuous length and may be of a size to extend across the road from one side to the other or may be'of a length which will extend from one side of the road to the center joint of the road. When the assembly is used to form a dowel bar contraction joint, the assembly is placed, upon the road sub-grade transversely of the road at the desired location and concrete is then poured to form the road slabs I and 2 to embed the dowel bar assembly, as illustrated in Figure 3. After the concrete has partially set, a. pre-molded filler strip or board 3 is positioned transversely of the road at the exact location where the joint or crack is to be formed in the concrete, and the flller strip is then pushed downwardly into the concrete until the top edge of the ller strip is slightly below the top surface of the concrete slabs I and 2, as illustrated in Figure 3. With the filler strip thus inserted into the concrete, the lower longitudinal edge of the iiller strip is positioned a short distance above the dowel bar assembly. This construction permits a joint crack 4 to be formed in the concrete below the filler strip 3 to separate the concrete to form the road slabs I and 2.

The present invention relates more particularly to the dowel bar spacing assembly for the joints, said assembly comprising a pair of separated parallel metal spacer plates 5. The spaced strips or plates 5 are of equal length and have the lengths thereof determined by the length of the contraction joint. Each of the spaced strips or plates 5 is provided with a plurality of spaced transverse slots l6, preferably arranged in the center line of the plate and in groups of two.

Mounted on each of the plates 5, in predetermined spaced relationship with respect to one another,

are a plurality of dowel bar brackets or holders provided with means for engaging through the slots 6 for holding the dowel bar brackets secured in place. f

Each of the dowel bar brackets or holders is constructed of sheet metal in afdeveloped form whichA is then bent into shape to provide an adjustable or split type of. dowel bar sleeve 'I of substantially semi-cylindrical form having end lugs or arms 8 which are bent downwardly and inwardly toward one another to form split end portions to serve as bottom supports for a dowel bar 9, as illustrated in Figures 6 and 7. Struck downwardly from one end portion of the dowel bar holding sleeve 1 is a dowel bar stop I0, against which the end of a dowel bar is adapted to seat to limit the insertion of the dowel bar in the sleeve, as shown. in Figure 5. The intermediate or middle portion of the bottom of the dowel bar supporting sleeve is open, due to the formation of a pair of supporting legs II formed from the dowel bar brackets or holders. The two supporting legs II extend downwardly and outwardly from the sleeve 'I preferably at an acute angle to one another and are each bent or shaped to be of angular cross-section with the ridge of the leg sections disposed on the inner side of the holder or bracket. By separating the legs the split sleeve may be opened or adjusted to receive dowel bars of different diameters. The legs may be moved .toward one another for closing the sleeve.-

Integrally formed on the lower end of each of the bracket or holder legs II is a foot I2 which is bent outwardly at an angle with respect to the respectiveleg and seats atly upon the top surface of the spaced strip or plate 5. Integrally formed on one end of each of the feet I2 is a toe or grip I3 which is positioned to project downwardly through one of the slots 6 vand is bent over and clamped against the bottom of the base plate, as clearly illustrated in Figure 6. It will thus be noted that each of the dowel bar holders or supports has the legs thereof rigidly secured to the base plate or strip.

As illustrated in Figure 2, the dowel bar supports or holders are mounted on the two spaced base plates 5 so that the holders are opposite one another to receive the opposite ends of the dowel bars or rods 9. The dowel bars 9 are thus held in proper spaced parallel relationship with respect to one another and connect the supporting units of the dowel bar assembly to form a continuous dowel bar joint unit which may be readily assembled on location and then placed as a unit upon a road sub-grade transversely of the road 1n proper position to permit the formation of a contraction joint in the road.

Figures 4 and 5 illustrate a modified form of the device for the formation of an` expansion joint i n a concrete road. In this form of the invention, the dowel bars and the dowel bar holders or4 supports are substantially the same as those described in connection with Figures 1 to 3, inclusive. In the modified form of the assembly, the toes or lugs I3 of the dowel bar holders or brackets project through slots in spaced plates or strips I4, the longitudinal margins of which are deected downwardly and outwardly to form inclined flanges I5 which are adapted to project downwardly into the subgrade or into the sub-grade covering, such as layers of paper or the like.

In the expansion joint type of dowel bar asy sembly, a pre-molded ller or core board I6 s provided which is of a type to extend from the sub-grade up to within a short distance of the top of the road slabs I1 and I8, in which the joint is embedded, as illustrated in Figure 5. The pre-molded filler board I6 is provided with spaced apertures or openings I9 through which the dowel bars 9 are adapted to be projected. When the dowel bars are projected through the iiller board, the ends of the dowel bars are engaged in the supporting sleeves 'I of the dowel bar holders or brackets which are mounted in spaced relation on the base plates I4.

` After the assembly of the dowel bar joint forming unit, the entire unit may be placed transversely of the road upon the road sub-grade, thereby properly holding the dowel bars in spaced parallel relation to extend through the filler board to permit the concrete to be poured for the formation of the road.

It will, of course, be understood that numerous details of construction may Vbe -varied through a wide range without departing from the principles of this invention, and it is, therefore, not the purpose to limit the patent granted hereon other- Wise than necessitated by the scope of the appended claims.

We claim as our invention:

l. A road joint dowel bar assembly comprising a pair of spaced parallel base plates for seating r dowel bar holders above each of the base plates,

legs on the holders for gripping the base plates for securing the holders in place, a plurality of dowel bars projecting across the space between the base plates with the ends of the dowel bars seated in the dowel bar holders to hold the dowel bars in spaced parallel relationship in the assembly, stop members struck inwardly from the dowel bar holders for engagement against the ends of the dowel bars, and a filler board forming part of the assembly and disposed transversely of the dowel bars between the base plates.

3. A road joint dowel bar assembly comprising a pair of spaced slotted base plates, a plurality of dowel bars projecting across the space between the base plates, and a plurality of vdowel bar holders engaged on the ends of the dowel bars and secured to the base plates, each of said dowel bar holders comprising a sleeve for receiving an end of a dowel bar, leg members in tegrally formed on the sleeve, feet on said leg members seated on the base plates, and toe members formed on said feet and clamped on the base plates for holding the dowel bar holders secured thereto.

e. A road joint dowel bar assembly including in combination a dowel bar holder comprising spaced split sleeve sections, a dowel vbar stop -member in one of said sleeve sections, b. semicylindrical sleeve portion integrally connecting the sleeve sections, supporting legs integrally formed on said sleeve portion, feet integrally formed on thelower ends of the legs, and clampport to hold the dowel bar holder secured in place. Y

5. A road` joint dowel bar assembly comprising a pair of spaced base plates for seating on a road sub-grade, a plurality of adjustable dowel bar holders for receiving dowel bars of different diameters, vlegs on said holders and secured to the base plates, with the legs of each holder pitched at an acute angle with respect to one another, and dowel bars projecting across the space between the base plates with the ends oi' the dowel bars engaged in the holders.

ing members on said feet for engaging a sup- 6. In a road joint dowel bar assembly including v in combination a dowel bar holder comprising 'a split sleeve, legs integrally formed on opposite sides and intermediate the ends thereof for supporting the sleeve and for opening and closing the same for engaging a dowel bar, and means on said legs for engaging the holder on a support.

'1. In a. road joint dowel bar'assembly including in combination a dowel bar holder comprising a sleeve having split end portions, a middle portion connecting said end portions, and supporting legs on said middle portion between lthe split end portions.

8. In a dowel bar assemblyincluding in combination a dowel bar holder comprising a base. legs secured thereto, and a sleeve portion integrally connecting the legs and having split end portions for engagement around a dowel bar.

LUKE C. THOMAS. ROBmT R.. ROBERTSON.

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