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@9 2%, Ji. H. „www LOAD TRANSFERENCE UNIT Filed Aug. 14, 1945 7/ `- mm2@ Patented Aug. 6, `l 946 2,495,428 UNITED STATES PATENT GFFICE _ 2,405,428 LOAD TRANSFERENCE UNIT _ J ames H. Jacobson, Chicago, Ill. Application August 14, 1943, Serial No. 498,660 2 Claims. (Cl. 94-17) . l The load transference unit of the present in vention is designed primarily for use in the con Fig. 4 is a modification showing the provision of anchoring members. struction of concrete highways, for the purpose of connecting the ends of adjoining road slabs, Each unit member in the form shown is formed from plate material cut or stamped to afford a flat body portion I0 having spaced arms I I extending upwardly therefrom to afford a gap I 2, the base of a manner as to prevent vertical displacement which is afforded by the middle edge section I3 of under the pressure of a rolling load on a highway, the body I0. runway or the like. With the opposed unit members aligned as in Before discussing the mechanical details of the 10 Fig. 1, the edges I3 afford support for a ñat dowel present invention it is proper to point out that bar I4, the middle portion of which bridges the the term “load transference unit” refers to the 'gap across the joint between the concrete slabs means employed for interconnecting the adjacent I5 of a road or similar structure which present ends of concrete road slabs across the gap» pro their ñat vertical faces I6 in opposed relation to vided for expansion and contraction and which one another. and transmitting load stresses across the gaps between the adjacent faces of the slabs in such unit includes members which are movable hori zontally to accommodate the advance and re Each of the unit members is provided with a rearwardly extending foot Il struck backwardly from one edge of the body portion to provide supporting contact with the surface of the sub vertical displacement of either of the slabs'with 20 grade, while the opposite edge is extended down respect to the other. In such an arrangement wardly in the form of a pointed spike I8 which it is of primary importance to distribute the is driven into the subgrade as shown in Fig. 3. stresses imposed by an approaching load, so that The dowel bar is of a width to lie between a considerable portion of such stress will be re the upstanding arms I I and is preferably, though sisted by the more distant slab, which thus serves 25 not necessarily, secured to one of the unit mem to reinforce the near slab which receives the in bers by a line of welding I9 and has sliding con itial impact of the advancing load, and it is also tact across the body of the companion member important to provide against vibration or similar to allow for expansion and contraction of the concrete due to thermal changes. The outer free movements which, unless counteracted, have a cumulative tendency to wear away the concrete 30 end of the dowel bar is entered into a sheath adjacent the unit members, and thus in time per 20 which is ñxedly embedded in the concrete and mit displacement of the unit with a resulting fail affords clearance for the in and out sliding move ure to perform the service intended. v ments of the dowel bar. The load transference unit members which are When the unit members are embedded within especially adapted for use with thin slabs, have the concrete slabs as in Fig. 3, the faces of the been designed with a view to extreme economy in opposed members will lie iiush with the vertical production, being in the preferred form of iden faces of the slabs while the oppositely extending tical stampings, which may be cut from a bar feet will be embedded around their top faces and of metal with little waste of material and bent edges with their under horizontally extended to ñnished form, ready for use, by a stamping 40 faces abutting flatwise with the subgrade. operation, and which need not be cut or formed While it will not ordinarily be necessary to pro with extreme precision in order to be interñtted vide additional anchoring means for holding the in the intended manner for use in a road joint. unit members in place within the concrete slabs, It will be understood, however, that the present nevertheless in some cases such anchors may be cession of the slabs, and which serve in conjunc tion with a dowel bar to bridge the gap and resist unit need not be formed as a stamping, but may be produced as a malleable unit or otherwise. Further objects and details will appear from the description of the invention in conjunction with the accompanying drawing, wherein Figure 1 is a perspective view of identical com panion unit members in their assembled relation; , desirable and in Fig. 4 I have shown upper middle and lower anchors 2|, 22, and 23 which enter deeply into the body of concrete and assist in anchoring the unit members against displace ment. The upper anchors are formed by striking 50 back the upper ends of the arms II while the lower anchor is formed by striking up the end of Fig. 2 is a face view of one of the unit members; the foot I'I. The middle anchor is formed by Fig. 3 is an edge View of the assembled unit em striking back a tongue cut free from the arms I I. bedded in the faces of opposed concrete slabs on One or more of such supplemental anchoring opposite sides of a road joint; and 55 devices or others of similar character may be em 2,405,428 3 ployed without otherwise modifying the struc ture or mode of operation of the device. In use properly spaced unit members are driven into the subgrade until the feet make con tact with the surface and thus afford stops for ensuring that companion members will stand at the same level so that the dowel bar, which is preferably connected with one of the members 4 tended horizontally to provide a ilat faced foot underlying the concrete and contacting the sub grade, a dowel bar bridging the space between the slabs and the unit members and supported between the spaced arms, and rigidly secured to one of the unit members, and having its ends extended backwardly therefrom and into the respective slabs, one end portion of the dowel bar will nt properly within the other. having a slidable contact with the other of said The free end of the dowel bar will be capped 10 unit members, and a sheath loosely arranged on with the sheath 20 which extends beyond the end said dowel bar end portion and located beyond of the bar, so that space will be aiîorded within the adjacent unit member and positionable on the concrete for the free sliding movements of the dowel bar independently of said adjacent unit the bar. With the unit members thus staked in member. position, and the dowel bar in place and with 15 2. In combination with concrete pavement suitable forms or spacers employed to provide slabs presenting opposed edge faces on opposite the intended gap between the slabs, the concrete sides of a gap, a load transference unit compris will be poured and compacted and built up to a ing oppositely facing unit members each formed level above the tops of the arms H, and if an of plate material adapted to afford great resist choring wings or flanges of the; character shown 20 ance to load stresses, and having a body and in Fig. 4 are employed, the same will be embedded spaced upwardly extending arms in the plane deeply within the body of the concrete. of the body and presenting their exposed faces The device is one which combines great ilush with the edge faces of said opposed concrete strength through its resistance to stresses, with tensile strength in resistance to shear. It may 25 slabs, the upper terminals of the arms being extended outward horizontally to provide upper be readily installed by simply driving-it into the anchors and the body of each unit member being earth to any desired height of dowel bar and still in part extended to provide a downwardly pro function correctly While the dowel bar itself is jecting spike entering into the subgrade and in held in place rigidly and at the same time is free to move horizontally. Although the form shown 30 part extended horizontally to provide a flat faced foot underlying the concrete and contacting the is one which combines extreme simplicity with subgrade, the terminal of the foot being extended cheapness in production, it is obvious that upwardly to provide a lower anchor, a middle changes in the shape or proportions of the con anchor rigid with and extending outward hori stituent parts may be made without departing zontally from the body at the lower end of the 35 from the spirit of the invention. space between said arms, a ñat relatively broad I claim: dowel bar presenting its flat upper and lower faces l. In combination with concrete pavement in horizontal planes and rigidly secured to one of slabs presenting opposed edge faces on opposite the unit members and bridging the space be sides of a gap, a load transference unit comprise tween the unit members and supported between 40 ing oppositely facing unit members each formed the spaced arms and having its ends extended of plate material adapted to afford great resist backwardly therefrom into the respective slabs, ance to load stresses, and having a body and spaced, upwardly extending arms in the plane of thebody and presenting their exposed faces one end portion of the dowel bar having a slidable contact with the other of said unit members, and a sheath loosely arranged on said dowel bar end ilush with the edge faces of said opposed concrete 45 portion and located beyond the adjacent unit slabs, the body of each unit member being in part extended to provide a downwardly projecting spike entered into the subgrade and in part ex member and positionable on the dowel bar inde pendently of said adjacent unit member. JAMES H. JACOBSON.