US3094908A - Expansion-contraction joint and groove form - Google Patents

Description

June 25, 1963 M. BERMAN EXPANSION-CONTRACTION JOINT AND GROOVE FORM 2 Sheets-Sheet 1 Filed May 7, 1962 June 25, 1963 M. BERMAN EXPANSION-CONTRACTION JOINT AND GROOVE FORM 2 Sheets-Sheet 2 Filed May 7, 1962 )h INVENTORA United States Patent() 3,094,908 EXPANSION-CGNTRACTIN JHNT GROVE FORM Morris Berman, G1120. Box 115, New York, NY. Filed May 7, 1962, Ser. No. 192,774 6 Ciaims. (Cl. 941S) 'Ihis invention relates to expansion-contraction joints for transferring applied loads from the end of one concrete slab to the contiguous end of an adjacent slab.

In the prior art such load transfer joints were frequently formed with doWels each having one half ixed in one slab end and the other half greased and slidable within the adjacent slab end through casting over dowel. This prior arrangement Was disadvantageous in that misalignment of the dowels or drying up or freezing of the lubricant within the holes would cause excessive friction or even complete binding of the dowels. 'Ihis in turn would either hinder or completely prevent expanding or contracting movements of the slab ends with temperature so as to cause breakage of the concrete slabs.

Other types of joints known in the prior art also produced excessive friction, irnpeding free relative lateral movement of the adjacent slab ends, or were too complicated, expensive, unreliable, or otherwise disadvantageous.

It is therefore a primary object of the present invention to provide a simple, effective and durable joint for transferring loads between adjacent slab ends and which will assure relatively free lateral expanding and contracting movements of the slab ends.

My copending application, Serial 182,5011, filed March 26, 1962 also shows means for transmitting loads between adjoining sections of expansion-contraction joints.

Another object is to provide a novel joint construction of the character described and forming a pocket or mold for Afiller material at the top of the space between the slabs.

Still another important feature of the invention resides in an arrangement whereby the pocket structure and ller material therein may be quickly and easily removed when the material requires replacement.

, Another object of the present invention is to provide a joint having cap plates which serve to mold the concrete-to form the slab ends with rounded upper edges so as to eliminate the prior burdensome need for sawing these upper edges.

t Other objects and advantages are either inherent in the structure disclosed or will become apparent to those skilled in the art as the detailed description proceeds in connection with the accompanying drawings wherein:

iFIG. 1 is a vertical section of a joint between slab ends along line 1--1 of FIG. 6` in which a compression member enga-ges one series of non-retractable shoulder members; this figure also shows the joint plates and diaphragm.

FIG. 2 shows an adjacent compression member en gaging a second series of shoulder members as seen in vertical section along the line 2 2 of FIG. 6, and in addition a slab forming cap inserted between the filler plates at the top thereof so as to form a curve at the upper edges of the slabs.

FIG. 3 is a vertical sectional View of a modied form of joint wherein several of the parts are readily removable for inspection and repair;

,FIG 4 isV a horizontal sectional view taken on line 4--4 of FIG. 3;

FIG. 5 is an enlarged vertical sectional view showing a portion of the structure of FIG. 3 but with the screw, bushing and other parts shown in section; and

FIG. 6 is a plan View of the joint with the side plates spaced apart to show the alternate series of compression members transferring the imposed load as shown in FIG- URES l and 2.

In FlG. 1, the ends of the adjacent slabs are numbered 10 and 11. The slab ends 10 and 11 are joined, in the invention, in a manner which causes loads applied to one slab end to be transferred to the other. The load transfer mechanism is indicated generally by the numeral 12 and comprises a pair of plates 13l and 14 which are spaced from one another across the space separating the slab ends 10 and 11.

The plates 13 and 14 are anchored to the respective slab ends 1G and 11, and appropriate means for this purpose are shown in FIG. 1. Thus, plates -13 and 14 may have welded thereto Ibond bars 15 and may also have wire mesh 16. Alternatively, the plates themselves may be deformed to provide the desired anchoring.

Each of the plates 13 and 14 are provided with inwardly facing upper shoulder elements 17 and lower shoulder elements 18. 'Ihe upper shoulder elements 17 face downwardly and the lower shoulder elements 18 face upwardly. As shown in FIG. 1, the upper and lower shoulder elements 17 and .1S are grooved and are unitary with or may be attached to the plates `13` and 14. More-` over, the upper and llower shoulder elements 17 and 18 are vertically spaced apart and compression elements or struts 19 extend between the upper shoulder elements of 'one plate and the lower shoulder elements of the other plate.

As will be apparent, FIG. 1 is a cross-section and only one of the upper shoulder elements 17 and only one of the lower shoulder elements can be clearly seen, the remaining shoulder elements being out of the plane of the section. Thus, and in FIG. 1, a load imposed upon slab end 16 is transferred to the slab end 11 by means of plate 13, strut 19 and plate 14, the load being transmitted through the shoulder elements 17 and 18. The transfer of imposed load from slab end 111 to slab end 12 is shown in FIG. 2.

As is well known, expansion and contraction joints between slab ends requires that the slab ends be permitted to move laterally to accommodate changes in the width of the space between the slab ends as the slabs expand and contract. Thus, the compression elements 19 are pivotally seated in the shoulder elements `17 and 18, the ends of the compression elements and the shoulder elements being preferably rounded, as shown, to provide the desired pivotal movement.

The invention is particularly illustrated in FIG. 1 in its application to concrete slabs which are poured about the plates 13` and 14 to cause the anchoring members 15 and'16 to become embedded within the concrete slab which is formed when the conc-rete sets. In this connection, it is common practice to ll the joint with a weatherproof elastic material and the invention includes means to facilitate the formation of the concrete slab end as well as means to hold the elastic material in place and to remove it when desired.

Referring to FIGS. l and 2, the upper ends of the plates 13 and 14 are slotted, as indicated at 20, and retractable joint filler container plates 21 are placed in the slots 20 and before the concrete is poured. Also, the cap` plates 22, as shown in FIG. 2, may be positioned at the top of the plates 2l to cause the poured concrete to'assume a Arounded upper edge. The 4filler container plates 21 carry mounted to lower shoulder element 18.

When it is desired to remove the elastic filler, the container plates 21 are extracted upwardly by force applied to the inwardly facing hook iianges 26 which are formed at the upper end of the Vcontainer plates 21.

The plates 21 may be pried loose from the concrete to facilitate extraction.

To facilitate adhesion of the top of plates 21 to the concrete, a bond material may be applied at the tcp of these plates. The remainder of the plates Z1 are greased on the slab sides for easier retraction for filler renewal.

Referring now to FIGS. 3 to 5, there is disclosed a modified form 12a of the invention wherein the several parts may be removed `for inspection and repair. In these figures those elements which are identical to corresponding elements of the previous modification 12 of FIGS. 1 and 2 are identified by the same reference numerals and will not be further described.

Plates 13a, 14a are similar to plates 13, 14 except that the yformer are provided with segment-ally -cylindrical recesses for receiving bushing segments 30, 31 secured ythereto as by welding or other suitable means. Segments 30, 31 are internally threaded to receive an externally threaded screw 32. A transverse slot 33 is formed in the upper end of screw 32 for engagement by a screwdriver bit, or a bolt head (not shown) may be provided as an alternative.

Each of the upper shoulder elements 17a, instead of being integral with one of the plates 13a, 14a as in the previous modification, is separate therefrom and movable with respect thereto. The lower shoulder elements 13 are formed integral with plates 13a, 14a as described above. That is, in one vertical plane the element 18 is integral with Vone plate 13a whereas the next element 18 in an adjacent vertical plane is integral with the other plate 14a, the elements altern-ating in this manner in the direction perpendicular to the plane of the drawing.

The upper end of strut 19 is pivotally mounted within the groove formed in the lower surface of upper shoulder element 17a and the lower end of strut 19 is similarly In assembly, screw 32 is rotated until its lower end presses downwardly upon shoulder element 17a which in turn exerts a compressive force on strut 19. Continued tightening of screw 32 causes the upper surfaces of the threads of screw 32 to press against the lower surfaces of the threads of bushing segments 30, 31, with clearance spaces between the lower surfaces of the threads of screw 32 and the upper surfaces of the threads of bushing segments 30, 31. The screw threads should project suiiiciently from the shank to permit adequate joint expansion without disengagement of the screw from the bushing.

It will thus be seen that a load on the left concrete slab will be transferred lto the right slab 1-'1 in the following manner: The lower thread surfaces of the left bushing segment 30 will press downwardly against the upper thread surfaces of screw 32 to transmit the load to the latter. However, the load will not be transmitted directly from screw 32 to the right bushing segment 31 because of the clearance spaces between the lower thread surfaces of screw 32 and the upper thread surfaces of bushing segment 31. Screw 32 is thus able to undergo sufficient downward movement with respect to bushing segment 31 to transmit the load to upper shoulder element 17a from which the load is transferred `to the right slab 11 through strut 19, lower shoulder element 18, and plate 14a.

The load is transmitted in the same manner from right slab 11 to left slab 10 in the alternate vertical planes where lower shoulder elements 118 are integral with left plate 13a instead of right plate 14a.

The several parts may be quickly and easily removed for inspection and repair by the following procedure. Filler container plates 21 and the filler material therebetween are first removed in the manner described above. Then slot 33 of screw 32 is lengaged by a screwdriver or Wrench and screw 32 is unscrewed from bushing segments 3l), 31 and removed upwardly from the joint. Upper shoulder elements 17a and struts 19 are then free to be removed, thereby providing access to the various parts and to the joint to the lower shoulder.

lt is to be understood that the specific embodiments disclosed herein are merely illustrative of several of the many forms which the invention may take in practice without departing from the scope thereof as delineated in the appended claims, and that the claims are to be construed as broadly as permitted by the prior art.

It is understood that any suitable material may be substituted for the concrete slabs referred to herein and the specifications and claims shall be so construed. It is `also understood that the term plates Kas used in these specifications and claims refer to any structural forms used to transmit loads. The term sla also includes licor or roof construction of any material.

I claim:

l. Load transfer mechanism adapted to be positioned between spaced slab endsfor transferring applied loads from one slab end to the other comprising, a pair of spaced plates including means for anchoring said plates to the respective slab ends, each of said plates being provided with laterally alternating inwardly projecting upper and lower shoulder elements, said upper and lower shoulder elements being vertically spaced and having seats facing downwardly and upwardly respectively, and compression elements extending between the upper shoulder elements of each of said plates and the lower shoulder elements of the other plate, said compression elements being pivotally seated in said shoulder seats.

2. Load transfer mechanism as recited in claim 1 in which said upper and lower shoulder seats fare rounded and said compression elements are struts formed with rounded opposite ends, said rounded ends of said struts being freely seated for pivotal movement within said rounded upper and lower shoulder seats.

3. Load transfer mechanism as recited in claim l in which the upper edges of said plates are -formed with downwardly extending slots, joint filler container plates -seated in said downwardly extending slots, the upper edges of said joint iiller container plates being formed with inwardly facing hooks, said joint iiller container plates together carrying 'a diaphragm for receiving elastic weatherproofing material.

4. A joint construction for :transferring applied loads tf1-om the end of `one slab to the contiguous end of an adjacent slab, said joint construction comprising a pair of plates, means ,for securing each of said plates toy a respective one of said slab ends, a iinst series of spaced upper shoulder elements on one of said plates, a lirst series of spaced lower shoulder elements each on the other of said plates located below a respective one of said upper shoulder elements, a irst series of compression elements each extending between [and engaging a respective one of said first series of upper shoulder elements and the respective lower shoulder element located therebeneath for transrmtting ta downward force from said first series of upper shoulder elements to sai-d first series of lower shoulder elements so `as to transfer a load from said one plate to said other plate, a second series of spaced upper shoulder elements on said other plate, a second series of spaced lower shoulder element-s on said one plate each located below Ia respective one of said second series of upper shoulder elements, said second series of shoulder elements :being staggered relative to said iirst 'series Iof shoulder `elements land la second series `of compression elements each extending between and engaging a respective one lof said second series of upper shoulder elements and the respective lower shoulder element located therebeneath :for transmitting -a downward force `from said second series of upper shoulder elements to said second Series of lower shoulder elements so as to transfer a load from said other plate to said one plate, said rst and second compression elements crossing each other in staggered relationship whereby said compression elements pivotally engage said shoulder elements.

5. A joint construction 'as defined in claim 4 wherein said means for connecting said upper shoulder elements to the plates comprises a plurality of pairs of bushing segments each pair being associated with a respective one of said upper shoulder elements, each segment being secured to a respective plate ,and having internal threads, a plurality fof externally threaded screws each extending between bushing segments of a respective pair and in threaded engagement therewith, the upper shoulder elernents lbeing movable with respect to the plates, the lower end `of each `of said screws engaging its respective upper shoulder element to transmit a downward torce thereto, whereby the screws may be unscrewed from the bushing segments to permit removal of the upper shoulder elements and the compression elements for inspection and repair yot the joint and said elements removed therefrom.

6. A joint construction as defined in claim 4 further comprising a plurality of pairs of bushing segments each pair being associ-ated with a respective one iof said upper shoulder elements, each segment being secured to a -respective plate and having internal threads, a plurality of externally threaded screws each extending between bushing segments of a respective pair and in threaded enga-gement therewith, the upper shoulder elements being vertically slidable between the plates, the lower end of each of said screws engaging its respective upper shoulder element to transmit :a downward force thereto, the bushing segment threads having lower surfaces engaging the upper surfaces of the external lthreads of said screws and having upper surfaces spaced downwardly from the lower surfaces of said external threads of said screws, the upper end of each screw having tool engageable means, whereby the screws may be unscrewed from the bushing segments to permit removal of the upper shoulder lelements and the compression elements for inspection Aand repair of the joint and said elme-nts removed therefrom.

References Cited in the le of this patent UNITED STATES PATENTS 1,320,222 Gage Oct. 28, 1919 2,066,052 Plym Dec. 29, 1936 2,093,718 Fremont Sept. 21, 1937 2,108,393 Schulz Feb. 15, 1938 2,183,484 Webb Dec. l2, 1939 2,330,213 Heltze-l Sep-t. 28, 1943 2,589,464 Webb Mar. 18, 1952

Claims (1)

1. LOAD TRANSFER MECHANISM ADAPTED TO BE POSITIONED BETWEEN SPACED SLAB ENDS FOR TRANSFERRING APPLIED LOADS FROM ONE SLAB END TO THE OTHER COMPRISING, A PAIR OF SPACED PLATES INCLUDING MEANS FOR ANCHORING SAID PLATES TO THE RESPECTIVE SLAB ENDS, EACH OF SAID PLATES BEING PROVIDED WITH LATERALLY ALTERNATING INWARDLY PROJECTING UPPER AND LOWER SHOULDER ELEMENTS, SAID UPPER AND LOWER SHOULDER ELEMENTS BEING VERTICALLY SPACED AND HAVING SEATS FACING DOWNWARDLY AND UPWARDLY RESPECTIVELY, AND COMPRESSION ELEMENTS EXTENDING BETWEEN THE UPPER SHOULDER ELEMENTS OF EACH OF SAID PLATES AND THE LOWER SHOULDER ELEMENTS OF THE OTHER PLATE, SAID COMPRESSION ELEMENTS BEING PIVOTALLY SEATED IN SAID SHOULDER SEATS.

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