US1600242A - Screed for concrete-paving machines - Google Patents

Description

. @IiZ/zizm Ufa if art agg- Filed Jan. 14, 1926 W 0RD scaszn FOR-CONCRETE PAVING MACHINES 7 Sept. 21 1926.

Patented Sept. 21, 1926.

UNITED STATES WILLIAI 0RD, OF CHICAGO, ILLDI'OIS.

SCREED FOB CONCRETE-PAVDIG MACHINES.

Application fled January 14, 1926. Serial No. 81,195.

This invention relates to what is known as a screed, surfacing member or strike-off member of a machine or device for compacting and surfacing concrete avements and has for its vobject'. to provi e a composite device including a flexible steel middle portion, a pair of removable and renewable inflexible end portions and removable and renewable wearing plates for saidend members which are cheap and are subjected to the greatest wear, said end members, furthermore, including means for preventing excess concrete disposed in their paths from assing over-the side-forms or side rails o the conventional pavement form on which said wearing plates of said end-members rlde during lateral reciprocation of the screed.

The invention is applicable to machlnes of the type shown in Letters Patent of the United States, granted to R. D. Baker, Nos. 1,390,457 9 and 1,388,690, the machine of Letters Patent No. 1,522,138 to William Ord and to all other machines wherein a laterally reciprocable screed or strike-ofi is employed and'is also applicable to manually manipulable devices of this character.

In the accompanying drawings, I have 11- lustrated the invention as applied to the particular type and construction of screed or surfacing member embodied in the aforesaid Ord machine without limitation, however, to its application to other types and constructions.

In'said drawings:

Fig. 1 is a front elevation of a screed or surfacing member constructed in accordance with the invention.

Fig. 2 is a plan view of the same.

Fig. 3 is a vertical section showing two spaced screeds, such as are illustrated in the aforesaid Ord machine.

Fig. 4 is a top plan view of an end-member of the screed or surfacing member detached from the middle portion.

Fig. 5 is an end elevation ofv the same.

In the instance illustrated, the surfacing member, screed or strike-ofl, consists of a rigid or substantially inflexible member 1,

such as a conventional steel I-beam, the web of which is vertically disposed, a conventional steel channel-bar 2, the web of which is disposed parallel with the flanges of the I-beam and whose edge-flanges extend upwardly from said web.

The said channel-bar 2 is of less length 68 than the distance between the side-forms or said rails of the pavement form over which the screed or beam is to be laterally reciprocated and is, in fact, sufliciently short to prevent its ends'from coming into contact with said side-forms, to obviate thereby the subjection thereof to the grinding due to the presence of sand and cement on the tops of the side forms.

The end-portions of the lower member of as the screed consist of castings each comprising a large'outer end portion 3 and a smaller inner end portion 4, the latter including a bottom plate and side flanges 5 relatively disposed and shaped to fit within the channel-bar 2 with said bottom plate resting upon the web and the side flanges 5 having their outer faces opposed to and contacting with the inner faces of the flanges of the channel-bar 2, to which they are suit II ably detachably secured by means, prefer ably, of the bolts 6. The bottom plates (indicated by reference character 4) of said inner ends of said members or castings are not co-extensive with the flanges 5, but'are cut away between the extreme endpor'tions of said flanges so as to provide a free space between said end-portionsof saidflanges. The latter are provided with opposed inwardly extending bifurcated projections 7 overhanging said free space and adapted to receive and engage the shanks of bolts 8 and the nuts 9 and 10 associated with the lower ends thereof.

The outer end-portions of said castings comprise each, a peripheral upstanding frame element or flange 11 consisting of continuations of the flanges 5 and offset there-- from to provide shoulders 12 to abut a ainst the ends of the flanges of the channelar 2. The frame elements 11 are integral with the are of considerably greater width than the lower face of the channel-bar, they wear away more slowly than if narrower and, being renewable at small cost and little labor, and without disturbing the adjustment of the channel-bar as to curvature, they present great economic advantage. This will be more readily appreciated when it is considered that said plates 15 must. be renewed after the device or machine has completed the compacting and surfacing of approximately five miles of pavement.

The said outer end-portions of said castings have straight rear walls and straight end-walls, the latter being perpendicular to therearxwalls The front walls, however, 0 extend ang'ularly to the rear and end walls orms, thereby to provide surfaces diverging forwardly from the-plane of the front face of the channel-bar. During reciprocation of the latter these angular surfaces tend to and do push masses of concrete-disposed in their aths forwardly and inwardly from the side preventing spill over the latter ,with consequent waste.

Integral with the rear walls of the outer end-portions, of the castings are inverted box-like formations 16 constituting bearing surfaces for guide rollers of the machine of the aforesaid Ord patent.

The said bolts 8 connect at their .upper ends with yokes 17 slidably mounted on the upper flanges of the I-beams 1 and of which a number are disposed between the two shown for connectionv with-the middle portions of the channel-bar 2 for flexing and adjusting the latter to curvature corresponding to the crown to be imparted to the pavement. The said yokes 8 and their connection with the said channel 2 are fully illuss trated and described in the aforesaid Ord patent.

It will, be appreciated by those skilled in.

the art that the average width of concrete highways is about twenty feet. The outer end portions 3 of the end members are approximately sixteen inches long and may, therefore, be inflexible.

Should the wearing lates 15 be a bit thin so as to be not quite ush with the bottom of the channel-bar when said plates 15 are secured in place, they may be properly adas they are renewed, in order to-avoid an ofi'set between their bottom surfaces and that of the channel-bar 2.

I claim as my invention:

1. A surfacing member for the purpose specified comprising a middle member and I two endmembers rigidly secured to each other, the end members having bottom surfaces oflset upwardly from the bottom surface of the middle member and being of greater width than the middle member, and wearing plates detachably secured to the bottom surfaces of said end members and having their bottom surfaces flush with the bottom surface of the middle member and being of dimensions corresponding with those of the bottoms of-the end members.

2. A surfacing member for the purpose set forth comprising a middle member having a flat bottom wall and parallel upstanding side flanges, end members each having an end portion fitting uponthe top surface of the bottom wall of said middle member and between the flanges of the latter and the including extension portions having each a bottom wall and a peripheralupstanding flange, the latter presenting a shoulder against which a flange of the middle member abuts, the bottom surfaces of the bottom walls of said extension portions being offset upwardly from' the bottom surface of the middle member a distance substantially' equal to the'thickness of wearing plates, and wearing plates of substantially sald thickness detachably secured to the bottom surfaces of said end members.

3. A surfacing member for the purpose specified, including a flexible middle member having parallel front and rearfaces, inflexible end members secured to the respective ends of said middle member and having rear faces disposed parallel with the rear face of said middle member, the *front portions of said end members presenting vertical faces extending at an incline to and projecting forwardly of the front face of t e middle member, the inclined front faces of said end members converging toward the front face of the middle member, wearing plates detachable secured to the bottoms of said end members with their lower faces substantially flush with the lower face of the middle member and abutting at their ends against the ends of said middle member, the said wearing plates being of greater width than the middle member over the portions thereof mainly subjected to wear.

4. A surfacing member for the purpose specified including a middle flexible member having a flat bottom wall ada ted to be posed substantially flush with the bottom flexed to a desired curvature, an end mem-' surface of said mlddle member, said outer 10 bers each having an inner end portion overend portions of said end members presenting lapping and rigidly seemed to said middle front walls an larly disposed to and pro- 5 member, the outer end portions of said memjecting forwar ly of the front ofsaid middle bers including a flat bottom wall and wearmember. Y ing plates abutting the ends of said middle memberand having their bottom faces dis- WILLIAM 0RD.

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