US3420491A - Tie rod assembly adapted for use in a concrete wall form and including novel elastomeric spacer members - Google Patents

Description

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1969 G. F. BOWDEN ETAL TIE ROD ASSEMBLY ADAPTED FOR USE IN A C WALL FORM AND INCLUDING NOVEL ELASTOMERIC SPACER MEMBERS Flled Oct 9, 1967 United States Patent 4 Claims ABSTRACT OF THE DISCLOSURE A tie rod assembly for concrete wall forms in which the tie rod has looped ends for connection to the form panels, breakbacks by means of which the rod is fractured to remove the looped ends from the hardened concrete wall, and elastomeric spacer members of special construction which are easily removed from the formed concrete wall. The spacer members are each of cylindrical configuration and include a central hollow cylindrical hub and an outer hollow cylindrical wall connected together by radial fins which resemble the spokes of a wheel. By inserting a screwdriver into the hub of each spacer member and twisting the same, the fins are placed in tension so as to shrink the outer wall and thus free the spacer member from its position of embediment.

The present invention relates generally to a tie rod assembly and has particular reference to a novel spacer member which is installed upon the tie rod of the assembly and functions in the manner of a conventional spacer cone to assimilate any inward thrust that may be exerted thereon by the adjacent wall form panel or panels and also to exclude the flow of wet concrete into the void or opening where the tie rod passes into the confines of the adjacent panel-formed side of the associated concrete wall form, but which is more easily extracted from its position of embediment in the surface region of the hardened concrete wall after the various wall form panels have been stripped from the wall.

In connection with that type of tie rod which is formed from cylindrical rod stock, it has long been the practice to provide loops, nail heads, or other forms of fastening means at the ends of the tie rod for anchoring purposes so that the rod may be connected at its ends to the opposite spaced apart sides of the associated concrete wall form, and also to employ rigid spacer members of frusto-conical design, such members being telescopically received over the rod in the vicinity of the looped or other ends. In the erected concrete Wall form, these spacer members assume positions close to or in contact with the inner concrete-receiving faces of the spaced apart form sides so that after the concrete is poured into the space between the sides of the form and has become hardened and then subsequent removal of the form sides, they remain embedded in the side surfaces of the resultant concrete wall while the ends of the tie rod project forwardly 0f the spacer members and are thus exposed. The tie rod is usually weakened near the inner ends or small bases of these spacer members in order to enable the projecting ends of the tie rod to be twisted and thus severed from the embedded medial or intermediate region of the rod, thus leaving the spacer members countersunk within comparatively deep sockets in the side surfaces of the finished or complete concrete wall. In order to facilitate extraction of these spacer members from the sockets in which they are embedded, the members usually are of frusto-conical configuration, thus giving rise to the name spacer cone or spreader cone which has long been applied to such spacer members whether they are truly frustoconical, cylindrical, or of some other configuration. Such rigid spacer members or cones are frequently extremely difficult to extract after use and if the application of twisting force to them is not sufiicient to dislodge them from their bonded relationship within their respective sockets in the side surfaces of the concrete wall, they must be intentionally fractured and then removed piecemeal.

- The present invention is designed to overcome the above-noted difficulty which is encountered in the extraction of conventional spacer members or cones from their positions of embedment in the side surfaces of a concrete wall, and toward this end, the invention contemplates the provision of a tie rod assembly in which the spacer members or cones that are associated therewith are formed of resilient elastomeric material, are partially hollow and consist of central hollow cylindrical hubs and outer hollow cylindrical walls in spaced apart and concentric relation with the hubs, the hubs and walls being connected together by annular series of flexible radially extending fins. The central hollow hubs afford mounting means whereby the spacer members may be telescopically received upon the end regions of the tie rod of the assembly in the usual manner of spacer cone mounting. The aforementioned novel spacer members function in the usual manner of spacer cone operation, but after the various panels of the associated concrete wall form have been stripped from the opposite sides of the hardened concrete Wall and the projecting ends of the tie rod of the improved tie rod assembly have been twisted, snapped and withdrawn from the wall, the spacer members may be extracted from their respective cylindrical sockets in the side surfaces of the concrete wall by the simple expedient of inserting a tool such as a screwdriver into the hubs endwise and twisting the latter so as to distort'the radial fins and place them under tension, thus shrinking the outer hollow cylindrical Walls so that they break their bond with the concrete. Withdrawal of the screwdriver thus pulls the adhering spacer members from the sockets in which they are embedded.

In addition to ease of removal, the advantages of resilient collapsible spacer members as parts of a tie rod assembly are manifold and among these advantages is the fact that the spacer members are reuseable since they are not damaged or destroyed in the process of extracting them from the finished concrete wall. Another advantage resides in the fact that the spacer members, when of cylindrical configuration, leave cylindrical sockets in the side surfaces of the concrete wall after removal of the members and these sockets, when filled or patched with plugs of concrete, securely retain the plugs so that they are unlikely to pop out of the sockets as is the case in connection with frusto-conical spacer members. A further advantage resides in the fact that cylindrical spacer members are easier to handle than are frusto-conical spacer members, there being no front or back ends so that they may be applied to a tie rod in either of two directions with the same net result. Additionally, the space members closely hug the tie rod proper and inhibit grout leakage along the rod. Finally, the resilient spacer members of the present invention lend themselves readily to an extrusion operation, thereby contributing to economy of manufacture. I

The provision of a tie rod assembly embodying resilient collapsible spacer members such as have briefly been outlined above constitutes the principal object of the present invention. Other objects and advantages of the invention will be readily apparent from a consideration of the following description.

The invention consists in the several novel features which are hereinafter set forth and are more particularly defined by the claims at the conclusion hereof.

In the accompanying single sheet of drawings forming a part of this specification, an illustrative embodiment of the invention is shown.

In these drawings:

FIG. 1 is a fragmentary top perspective view of a concrete wall form employing tie rod assemblies embodying the principles of the present invention;

FIG. 2 is a fragmentary top perspective view of a portion of a concrete wall from which the wall form panels have been removed, said view showing one end of one of the embedded tie rods of the assemblies preparatory to fracture and removal of said one tie rod end and subsequent extraction of the associated resilient spacer member from its socket in the wall;

FIG. 3 is an end view of an embedded spacer member preparatory to an extraction operation; and

FIG. 4 is an end view similar to FIG. 3 but illustrating schematically the manner in which the spacer member may be extracted from its encompassing socket in the concrete wall form.

Referring now to the drawings in detail and in particular to FIG. 1, a typical concrete wall form employing tie rod assemblies constructed according to the present invention is designated in its entirety by the reference numeral and the improved tie rod assemblies forming parts of the concrete wall form as a whole are designated by the reference numeral 12. These tie rod assemblies 12 are capable of use with a wide variety of concrete wall forms, such, for example, as concrete wall forms employing panels having either wooden or metal reinforcing studding for the usual rectangular plywood facings, or having no studding whatsoever. Furthermore, the tie rods of the assemblies 12 may extend across the concrete wall form 10 either at the juncture region between adjacent panels or they may bridge the form by extending through centrally disposed regions of the opposed and spaced apart individual panels. However, for exemplary purposes herein, the tie rod assemblies 12 are shown as being associated with a concrete wall form employing steel-studded prefabricated panels 14 of the type which is commonly known in the concrete forming industry as a Steel-Ply panel and is manufactured and sold by Symons Mfg. Company of Des Plaines, Ill. Such panels are widely known in the industry and although only the fragmentary edge regions of abutting pairs of panels are disclosed in the drawings hereof, it will be understood that each panel is of shallow open tray-like design and includes a rectangular plywood panel facing 16 and a marginal reinforcing frame including vertical frame members 18 and horizontal frame members (not shown). At appropriate levels intermediate horizontal steel crossbars 20 extend between and are welded to the opposed vertical frame members 18. Both the vertical and horizontal frame members are in the form of structural steel bars which are of shallow channel shape in cross section and each bar includes inner and outer outwardly extending marginal ribs 22 and 24, and a connecting web portion 26. On the side of each web portion that is opposite to the ribs 22 and 24 is a lateral inwardly extending flange 28 on which the adjacent edge of the plywood facing 16 seats with its inside face flush with the inside edges of the frame members. At vertically spaced regions along the outwardly extending ribs 22 and 24, pairs of transversely registering notches 30 are formed and these notches, when the frame members are in contiguity, define therebetween horizontal channel voids 32 which are adapted to receive therethrough the adjacent looped ends of the tie rods of the tie rod assemblies 12 as will be described presently. A rectangular slot 34 is formed in the web portion 26 of each frame member at the level of each pair of notches 30 and such slot is adapted to receive therethrough the shank portion of a T-bolt 36. A wedge 38 which is driven through a longitudinal slot in the shank of the T-bolt 36 serves to place the T-bolt under tension and thus draw adjacent or contiguous vertical frame members 18 tightly together.

The arrangement of parts thus far described is purely conventional and no claim is made herein to any novelty in it, the novelty of the present invention residing rather in the particular novel construction and arrangement of parts of the tie rod assemblies 12 and they will now be described in detail. Since all of the tie rod assemblies 12 are the same, a description of one will suflice for all.

Still referring to FIG. 1, the illustrated form of tie rod assembly 12 involves in its general organization a normally horizontal tie rod proper 40 which is in the form of a length of cylindrical rod stock and has integral looped ends 42. The latter are adapted to encircle the shanks of the associated T-bolts 36 or otherwise be attached to the opposite sides of the concrete wall form 10. At regions spaced inwardly from the looped ends 42 the metal of the tie rod 40 is flattened as shown at 44 in order to provide weakened portions which are commonly known in the art as breakbacks and by means of which the looped ends of the tie rod may be readily severed from the concrete-embedded medial region of the rod by twisting them after hardening of the concrete wall and removal or stripping of the panels 14 from the wall.

Mounted on the tie rod 40 and interposed between each breakback 44 and its adjacent looped end 42 is a spacer member 50 of novel design, such member constituting one of the principal features of the present invention. Flat washers 45 are interposed between each spacer member 50 and the adjacent breakback 44. Each spacer member is formed of a suitable elastomeric material such as rubber, either natural or synthetic, or a rubber substitute, and involves in its general organization a central hollow cylindrical hub 52 and an outer hollow cylindrical wall 54 (see particularly FIG. 3) in spaced apart and concentric relation with the hub, said hub and wall being connected together by a series of flat radially disposed connecting fins 56. The various fins 56 are equally spaced from one another and define longitudinal voids 58 therebetween, eight such fins being illustrated in the drawings hereof although it will be understood that a greater or lesser number of such fins may be employed if desired. Each spacer member 50 is of integral or onepiece construction and assumes the same cross sectional shape from end to end.

The aforementioned tie rod assembly 12 is adopted for use in connection with a concrete Wall form such as the fragmentarily shown form 10 in substantially the same manner as a conventional or standard tie rod assembly, the looped ends 42 of the tie rod 40 being arranged in encircling relation with the shanks of the T-bolts 36 as heretofore set forth and the tie rod being arranged so the portions thereof immediately inwards the looped ends to project through the channel voids 32 in the inner outwardly extending ribs 24 of adjacent vertical frame members 18. The outer ends of the spacer members 50 assume positions in contiguity or abutment with the inner side faces of the adjacent ribs 24 so that they serve to seal the adjacent channel voids 32 against seepage of the wet concrete out of the space between the sides of the concrete wall form 10. The washers 54 which bear inwardly against the breakbacks 44 and abut against the inner ends of the spacer members 50 hold the spacer members against inward sliding movement on the medial portion of the tie rod 40, and the length of the looped ends 42 and the disposition of the breakbacks 44 is such that the members 50 are tightly held between the breakbacks and the adjacent form sides.

After the concrete is poured between the two form sides and has become set or hardened, the wedges 38 are driven out of connected relation with the slotted shanks of the associated T-bolts 36, the latter are removed from the slots 34, and the panels 12 are stripped from the resulting concrete wall 60 (see FIG. 2). The medial region of the tie rod 40, togther with the spacer members 50 and their associated washers 45 remain embedded within the concrete with the outer end faces of the spacer members being exposed and flush with the side surfaces of the concrete wall 69 as shown in FIG. 2. The projecting looped ends 42 of the tie rod 40 of the tie rod assembly 12 are then worked back and forth and twisted until such time as these ends break loose from the medial region of the rod in the vicinity of the breakbacks 44, the elastomeric hubs 52, and the vanes 56 of the spacer members 50 yielding during such movement of the looped ends so that little opposition is ofiered to such working of the looped ends of the tie rod 40. After the projecting looped ends of the tie rods have thus been removed, the spacer members 50 and the washers 45 remain embedded in the cylindrical sockets 62 (see FIGS. 3 and 4) which are established by their presence in the concrete wall 60.

Removal of either embedded spacer member 50 may be accomplished by exerting a rotational or twisting action on the hub 52 of the member and this may be expediti ously accomplished by inserting the working end of a suitable torque tool such as a screwdriver (shown in section at T in FIG. 4) into the sub and then turning the tool in one direction or the other. The phenomena by meas of which such manipulation of the tool efifects loosening of the associated spacer member 50 from its socket 62 in the concrete Wall 60 by breaking the adherence bond between the rubber and the concrete is ill-ustrated in FIG. 4. It will be observed that as the tool T is turned in a counterclockwise direction as indicated by the arrow in this view, the hub 52 will become deformed to substantially the cross sectional shape of the tool, While at the same time the normally radial fins 56 will be deflected and thus place under tension so as to draw portions of the outer wall 54 inwardly. The net re"ult of such tensioning of the fins 56 is to shrink the entire spacer member and pull the outer elastomeric wall 54 away from the wall of the surrounding socket 62, after which withdrawal of the tool will serve to lift the spacer member 50 bodily from the socket 62. The adjacent washer 45 re mains at the bottom of the socket 62 and the latter may be fiilled with patching cement in the usual manner of filling spacer cone voids. Inasmuch as during concrete pouring and hardening operations, the washers 45 substantially close the inner ends of their associated spacer members 50, concrete may not flow into the interior of, or the voids 58 in, the spacer members and these members, after extraction from the wall 60, are in condition for reuse with little or no cleaning operations being required.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying one sheet of drawings Or described in this specification as various changes in the details of construction may be resorted to without departing from the spirit or scope of the invention. For example, while the novel spacer members of the present invention are shown as being associated with a tie rod proper 40 of the type having looped ends by means of which the tie rod may be attached to the opposite form sides, such spacer members are equally applicable to a tie rod having other attachment means at its end regions. Therefore, only insofar as the invention is particularly pointed out in the accompanying claims is the same to be limited.

Having thus described the invention what we claim as new and desire to secure by Letters Patent is:

1. As a new article of manufacture, a tie rod assembly adapted for use in connection with a concrete wall form and comprising a tie rod in the form of a length of cylindrical rod stock, having means at the opposite ends thereof whereby the rod may be attached to the opposed sides of the concrete wall form, and also having 'breakbacks disposed inwardly from said ends, and integral one-piece spacer members telescopically disposed on said tie rod and interposed between said ends and the breakbacks, each spacer member being formed of resilient material and including a centrally disposed inner hollow cylindrical hub closely surrounding the rod, an outer hollow continuous wall spaced from and surrounding the hub, and an annular series of radially extending fins extending between the hub and the wall and adapted, when the hub is rotated in either diretcion about its longitudinal axis and relatively to the outer wall, to be placed under tension to thereby shrink the over-all diameter of the spacer member and thus permit ready removal of the member from the concrete wall that is formed by the form.

2. A tie rod assembly as set forth in claim 1 and wherein the outer wall of each spacer member is truly cylindrical.

3. A tie rod assembly as set forth in claim 1 and wherein the radially extending fins of each spacer member are substantially flat and of substantially uniform thickness throughout.

4. A tie rod assembly as set forth in claim 1 and including, additionally, a metal washer interposed between each spacer member and its adjacent breakback and serving to cover and seal the inner ends of the spaces between the fins.

References Cited UNITED STATES PATENTS 2,029,147 1/ 1936 Anderson 249-217 WILLIAM J. STEPHENSON, Primary Examiner. DE WALDEN W. JONES, Assistant Examiner.

US. Cl. X.R. 25-13l

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