AU2017204064A1 - Variable height accessory placement chair - Google Patents

Abstract

A variable height chair for positioning an accessory within a horizontal concrete forms, comprising a base portion having a vertically-oriented, internally-threaded socket, and an externally-threaded accessory that mates with the internally-threaded socket for screw like travel within the socket. The internally-threaded socket includes at least one vertically-oriented internal detent, and the externally-threaded accessory includes at least one longitudinally-interrupted thread section so that upon rotational movement of the accessory within the socket the internal detent cyclically engages the interrupted thread section and positions the accessory at one of a plurality of regularly spaced-apart vertical positions with respect to the base portion. 160 f180 120a12 129-10

Description

TITLE

VARIABLE HEIGHT ACCESSORY PLACEMENT CHAIR

This application claims priority from US Application No. 62/506,509 filed on 15 May 2017, the contents of which are to be taken as incorporated herein by this reference.

BACKGROUND 1. Technical Field [0001] The present disclosure relates generally to chairs and spacers that are used in construction for the placement of accessories within formed concrete members, and in particular to a chair for use within horizontal concrete forms that positions an anchorage insert, ledger support, or other accessory for embedment within a cast concrete member at one of many selectable heights. 2. Description of the Related Art [0002] Chairs or spacers are commonly used in the construction industry for the placement and vertical positioning of steel reinforcement members and various accessories within horizontally-cast concrete structural elements such as site-cast tilt-up wall sections. Lifting inserts, anchorage inserts, and other accessories can be placed within a horizontal concrete form and positioned at a specific height above the base of the form via wire or plastic chairs to embed an accessory within a specified depth of concrete and/or to position a portion of the accessory flush with the intended surface of the poured concrete. Customarily manufacturers produce accessories using chairs of various heights, and end users must order and inventory accessories with chairs that match the planned thickness of each horizontally-cast structural element. Locating plugs may be provided to cover accessory openings so that the accessories are not fouled and so that, after casting, any inadvertent concrete cover can be removed from the embedded accessory. Various accessories are used for tilting-up and/or carrying cast wall sections, for temporarily attaching wall braces to raised wall sections, and for permanently attaching structural and non-structural building elements to raised wall sections.

[0003] Some chair designs provide for variable height positioning and placement of rebar by offering optional fittings or providing multiple receptacles positioned at different heights. For example, U.S. Pat. No. 6,089,522 to Haslem et al. discloses a stackable high chair having an upper connecting portion with an upper support surface for supporting steel reinforcement bars (“rebar”), as well as optional head pieces that may be fitted over the upper connecting portion, each with a similar support surface for supporting rebar further above the upper support surface. The chair may be used without a head piece to position rebar at one height above the base of a horizontal concrete form, or with one of several different head pieces to add additional height. The optional head pieces are smaller and less expensive than a unitary chair, but are subject to the same manufacturing, ordering, and inventory issues mentioned above. For further example, U.S. Pat. No. 7,497,059 to Bennett discloses an arch-like multi-level cable support chair that includes multiple receptacles disposed at different, regularly spaced-apart heights, as well as a slotted cable support chair that provides multiple receptacles disposed at regularly spaced-apart intervals within an extended-length vertical slot. Such chairs are well-suited for supporting horizontally-laid rebar or cable within a horizontal form, but not for supporting vertically-oriented accessories and not for distribution as preassembled devices that include the accessory.

BRIEF SUMMARY

[0004] The applicants have discerned a need for a variable height accessory placement chair that provides a significant range of vertical positioning for accessories such as anchorage inserts or ledger supports, yet has a simple and strong construction. Such a device should preferably be shippable, adjustable, and useable as a pre-assembled device.

[0005] Disclosed is an injection-moldable, variable-height placement chair comprising a base portion having a vertically-oriented, internally-threaded socket for an externally-threaded accessory that mates with the socket for screw-like travel within the socket. The internally-threaded socket includes at least one vertically-oriented internal detent, and corresponding externally-threaded accessories include a longitudinal shaft having at least one longitudinally-interrupted thread section so that upon rotational movement of the accessory within the socket the internal detent cyclically engages with the interrupted thread section. Accordingly, screw-like advancement or withdrawal of an accessory within the internally-threaded socket, stopping at a point of engagement between the internal detent and the interrupted thread section, positions the accessory at one of a plurality of regularly spaced-apart vertical positions with respect to the base portion.

[0006] In a first aspect, the corresponding accessory may be an anchorage insert having the longitudinal shaft and a distal socket for receiving a connector, with the longitudinal shaft itself having the external thread(s) and longitudinally-interrupted thread section(s). In an exemplary aspect, the anchorage insert may be a unitary plastic insert having the distal socket, external thread(s), and longitudinally-interrupted thread section(s), and optionally be combined with a separate distal locating plug fitted within the distal socket.

[0007] In a second aspect, the anchorage insert may comprise an assembly of a sleeve and an anchorage core, with the anchorage core having the longitudinal shaft and the distal socket, but the sleeve having the external thread(s) and longitudinally-interrupted thread section(s) and fixedly sheathing the longitudinal shaft. The sleeve may optionally be manufactured from plastic and integrally formed with a plastic distal locating cap that is positioned to cover the distal socket and connected to the sleeve by a thin plastic web. Thus, in another exemplary aspect, the anchorage insert may be an assembly of a metal anchorage core and a plastic sleeve having the integrally formed distal locating cap. The Applicant notes that in the second aspect the anchorage core may have a simplified construction or be of a type that is not easily provided with external threads, e.g., be an anchorage insert manufactured from structural steel.

[0008] The corresponding accessory is not limited to anchorage inserts. In a third aspect, the corresponding accessory may be a ledger support for embedded bearing ledgers. The ledger support may have the longitudinal shaft and a distal support platform or saddle disposed at a distal end of the shaft. As in the first embodiment, the longitudinal shaft itself may have the external thread(s) and longitudinally-interrupted thread section(s). In other aspects, the corresponding accessory may be a lifting anchor, a coil anchor, an embedded angle or plate, a rebar support, a screed support, etc. A corresponding accessory may have the integral external thread(s) and longitudinally-interrupted thread section(s) or a longitudinal shaft fixedly sheathed by the aforedescribed sleeve. In each aspect, screw-like advancement or withdrawal of the corresponding accessory within the internally-threaded socket can position the accessory at one of a plurality of regularly spaced-apart vertical positions with respect to the base portion.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a perspective view of an exemplary variable height anchorage insert placement chair; [0010] FIG. 2 is a cross-sectional view of a base portion of the placement chair of Fig. 1 and, in particular, of an internally-threaded socket of that base portion; [0011] FIG. 3 is a cross-sectional view of a variable height anchorage insert placement chair with a unitary externally-threaded insert and an optional locating plug; [0012] FIG. 4 is a cross-sectional view of a variable height anchorage insert placement chair with an externally-threaded plastic sleeve, metal anchorage core, and an optional integrally formed distal locating cap; [0013] FIG. 5 is an exploded perspective view of the variable height anchorage placement chair of FIG. 4; and [0014] FIG. 6 is an exploded perspective view of a variable height ledger support placement chair.

DETAILED DESCRIPTION

[0015] Referring first to FIG. 1, a perspective view is shown of an exemplary variable height accessory placement chair 100. The chair 100 has a base portion 110 for placement upon the base of a horizontal concrete form, and may include a plurality of downwardly-oriented legs 120 where adjacent legs, e.g., 120a and 120b, define holes or apertures 130 therebetween which allow poured concrete to pass fluidly through the chair. The individual legs 120a, 120b, etc. are shown as being arrayed at generally equal intervals to form the comers of a square, but the chair may have a greater or lesser number of legs and the legs may be configured to form the comers of any desired regular or irregular-shape such as a triangle, quadrangle, pentagon, etc. The base portion 110 may also include a plurality of upwardly-oriented arms 122, each connected to one of the plurality of legs 120 and to others of the pluralities of arms 122 and legs 120 by brace members 124. If provided, the arms 122 and brace members 124 will define additional apertures 132 therebetween which should likewise be sized to allow poured concrete to pass fluidly through the chair. The legs 120 may terminate in foot members 126 or other structures whose configuration is not critical, but generally will include terminal inverted cones, hemispheres, or similar structures 128 with progressively narrowing crosssectional areas so as to minimize contact between the base portion 110 and the base of a horizontal concrete form, thus minimizing discontinuities in a concrete surface that may later become an exposed surface of an assembled structure. The legs 120 and/or arms 122 may include ridges, notches, or other similar structures 127 to permit the chair to be secured to a rebar mat using wire ties or other fasteners.

[0016] The base portion 110 supports a vertically-oriented, internally-threaded socket 140. Referring now to TIG. 2, the internally-threaded socket 140 includes at least one flight of internal thread 142 for screw-like guidance of an accessory, e.g., an anchorage insert 160, within the socket. The internal thread 142 preferably has a relatively large pitch, e.g., 1/2 inch of vertical displacement per complete thread flight, and thus can also be relatively wide, e.g., 1/8 inch to 3/8 inch wide. As shown, the internal thread 142 may be discontinuous. The internally-threaded socket 140 also includes at least one vertically-oriented internal detent 144. In one exemplary construction, not specifically shown, the internal detent 144 may simply be an inwardly-projecting ridge provided on the interior wall of the socket. The internal detent 144 is preferably rounded to permit advancing and withdrawing rotation of an accessory, but could be provided with an only-partially-rounded or ramp-like cross-section to lock an accessory against one direction of rotation. Such an internal detent 144 would be displaced by the threads of the accessory and flexing of the material of the internally-threaded socket 140.

[0017] In a preferred construction, the internally-threaded socket 140 includes a circumferentially projecting arm 146 partially defining the interior wall of the socket, with a free end of the arm 148 carrying the internal detent 144. The free end 148 and internal detent 144 would again be displaced by the threads of the accessory, but be more easily displaced through bending of the arm 146. The internally-threaded socket 140 may, in some constructions, include a radially outwardly-displaced wall section 150 that defines a niche 152 for displacement of the free end 148 and internal detent 144, and that also serves to shield the circumferentially projecting arm 146 from damage. However, it will be appreciated that the wall section 150 and niche 152 are not critical, so that the circumferentially projecting arm 146 may partially define both the interior wall and the exterior wall of the internally-threaded socket 140.

[0018] Turning to FIG. 3, the internally-threaded socket 140 receives an externally-threaded accessory such as anchorage insert 160. An externally-threaded anchorage insert 160 may have a longitudinal shaft 161 that includes at least one flight of external thread 162 (best seen in FIG. 5) for mating with the internal thread 142 of the socket 140 and screw-like travel of the anchorage insert within the socket. The threaded longitudinal shaft 161 would then also include at least one longitudinally-interrupted thread section 164 so that upon rotational movement of the anchorage insert 160 within the internally-threaded socket 140, the internal detent 144 cyclically engages with the longitudinally-interrupted thread section. The longitudinally-interrupted thread section 164 may be shaped to correspond to the shape of the at least one internal detent 144 and/or may include a longitudinal groove 166 shaped to releasably capture the internal detent. The longitudinal shaft 161 of the illustrated anchorage insert accessory 160 also includes a distal socket 170 for receiving connector such as an anchor bolt, during, for example, attachment of a temporary wall brace when erecting a cast wall section. Accordingly, stopping rotational movement of the anchorage insert 160 at a point of engagement between the internal detent 144 and the interrupted thread section 164 reliably and, if necessary, repeatably positions the distal socket 166 at one of a plurality of regularly spaced-apart vertical positions with respect to the base portion 110.

[0019] There do not need to be an equal number of internal detents 144 and longitudinally-interrupted thread sections 164. For example, as indicated in FIGs. 2 and 3, the socket 140 may include a single internal detent 144 and the accessory may include two longitudinally-interrupted thread sections 164, arranged 180 degrees apart about the perimeter of accessory, so that rotating the accessory by 180 degrees advances (or withdraws, depending upon the direction of rotation) the accessory by one half of the pitch of the internal thread 142 with respect to the base portion 110 of the chair. If multiple longitudinally-interrupted thread sections 164 are provided, they may be arrayed at equal intervals about the perimeter of the accessory so that screw-like advancement or withdrawal of the accessory within the internally-threaded socket 140 positions the accessory at one of a plurality of regularly spaced-apart vertical positions with respect to the base portion 110. Where only one longitudinally-interrupted thread section 164 is provided, screw-like advancement or withdrawal of the accessory within the internally-threaded socket 140 will naturally position the accessory at one of a plurality of such positions.

[0020] The exterior of the anchorage insert 160 (or, more generally, any corresponding accessory) may be provided with indicia 168 (shown in FIG. 1) displaying the relative vertical position of the distal socket 166 (or, more generally, any reference point of an accessory) with respect to the bottom of the base portion 110 (e.g., the foot members 126 or terminal structures 128), the top of the vertically-oriented socket 140, or another reference point of the base portion 110. For example, as shown in FIGS 1 and 5, the external threads 162 of the anchorage insert 160 may be formed or impressed with indicia 168 such as “ + 1/4” ” to display that the top of the accessory has been positioned 1/4 inch above the top of the vertically-oriented socket 140. For further example, the land above each external thread 162 may be formed or impressed with such indicia 168. Additional indicia 129 may be provided on the base portion 110 which, when combined with the indicia 168 on the anchorage insert 160, serve to provide a combined indication of the relative vertical position of the accessory with respect to the base of a concrete form or some other device reference point. For example, such additional indicia 129 may display the vertical position of the top of the socket 140 or another reference point of base portion 110. Such additional indicia 129 may also be useful for indicating the depth of the concrete cover at that location, where to secure wire ties between the base portion 110 and a rebar mat so that the chair 100 may partially support the rebar mat at a desired height while being held in position by the rebar mat, etc.

[0021] In use the anchorage insert 160 may be used to connect equipment such as wall braces for supporting raised wall sections during construction. As shown in FIG.3, the anchorage insert 160 may be a unitary plastic insert, preferably manufactured from an injection-moldable material such as polypropylene or nylon, having the external thread(s) 162 and longitudinally-interrupted thread section(s) 164 formed on its exterior surface, the indicia 168 formed on or impressed into its exterior surface, and internal threads 172 formed on or cut into the interior surface of its distal socket 170. The anchorage insert 160 may include a flared foot 174 for resisting pull-out after embedment within the cast concrete. Such anchorage inserts 160 may also be provided with a separate locating plug 180 that is fitted within the distal socket 170 (e.g., by friction fit or threaded engagement with the internal threads 172) to prevent poured concrete from filling the distal socket 172 or obscuring the location of the socket within the face of the formed element.

[0022] In a second aspect, shown in FIGs. 4 and 5, the anchorage insert 160 may comprise an assembly of a sleeve and an anchorage core, with the anchorage core 160a having the longitudinal shaft 161 and the distal socket 170, and the sleeve 160b having the external thread(s) 162, longitudinally-interrupted thread section(s) 164, as well as the longitudinal groove(s) 166 and indicia 168, if included in the accessory. The anchorage core 160a may be manufactured from metal, e.g., structural steel, and the sleeve 160b may be manufactured from plastic, e.g., an injection-moldable plastic such as polyethylene, polypropylene, or nylon. Although anchorage inserts 160 such as that of the first aspect could be manufactured from metal, the second aspect advantageously simplifies the structure of the core 160a of the anchorage insert so that extensive machining and deburring or polishing of a casting is not required. A plastic sleeve 160b may optionally be integrally formed with a plastic distal locating cap 190 that is connected to the plastic sleeve by a thin plastic web 192 (0.002-0.01 inches thick), or at least significantly thinner than the average thickness of the wall of the sleeve 160b, and positioned over the distal socket 170 of the anchorage core 160a. Sleeve 160b may then be friction fit, adhesively secured, or otherwise attached to fixedly sheath the anchorage core 160a. In one exemplary construction, the exterior surface of the anchorage core 160a includes a knurled section 176 that that provides an interference fit within sleeve 160b.

[0023] It will be appreciated that other types of anchorage inserts, including anchorage cores having sockets formed from metal coils for connectors such as coil bolts, may be used to anchor some sorts of equipment and accessories. The plastic sleeve 160b may fixedly sheath a metal coil anchorage core (not shown) providing a distal socket 170 formed by the internal surface of the coil. Such a metal coil may include at least one depending and flared loop, extending below a proximal end of the plastic sleeve 160b and functioning similarly to the flared foot 174, formed from the coil wire or from other wire having ends welded to the surface of the metal coil. The proximal end of the plastic sleeve 160b in such a device may be sealed with a moldable, thermoplastic, or curable material so that, in combination with a separate locating plug 180 or an integral locating cap 190, the distal socket 170 is protected from fouling with poured concrete.

[0024] It will also be appreciated that other types of corresponding accessories may be combined with base portion 110 to form other types of accessory chairs. In a third aspect, shown in FIG. 6, the chair 100 includes a ledger support accessory. The ledger support 200 may have a longitudinal shaft 201 that includes at least one flight of external thread 202 for mating with the internal thread 142 of the socket 140 and screw-like travel of the ledger support within the socket. The threaded longitudinal shaft 201 would then also include at least one longitudinally-interrupted thread section 204 so that upon rotational movement of the ledger support 200 within the internally-threaded socket 140, the internal detent 144 cyclically engages with the longitudinally-interrupted thread section. Alternately, the longitudinal shaft may be fixedly sheathed by the aforedescribed sleeve 160b (not shown). The longitudinal shaft 201 also includes a distal support platform 210 for supporting a embeddable bearing ledger within a form and a cast concrete element until the casting has cured. Accordingly, stopping rotational movement of the ledger support 200 at a point of engagement between the internal detent 144 and the interrupted thread section 204 (or an interrupted thread section of sleeve 160b) reliably and, if necessary, repeatably positions the distal support platform at one of a plurality of regularly spaced-apart vertical positions with respect to the base portion 110. The longitudinal shaft 201 may accordingly be provided with indicia 208 (e.g., “ +1/4” “ +3/4” etc., as shown in Fig. 6) displaying the relative vertical position of the distal support platform 210 with respect to the bottom of the base portion 110, the top of the vertically-oriented socket 140, or another reference point of the base portion 110. In variations of the third aspect, the distal end of a longitudinal shaft 201 may include a saddle for supporting the embeddable ledger support and restraining the embeddable ledger support against lateral movement during pouring of the concrete. In general, the distal end of a longitudinal shaft of an corresponding accessory may have a distal receptacle, support surface, or connector, and the proximal end of the longitudinal shaft may simply terminate or have a flared foot, flared loop, unflared loop, or other anchor structure, as required or desired for a particular application. In general, the corresponding accessory may be a unitary accessory or a multipart accessory having a core fixedly sheathed by the aforedescribed sleeve.

[0025] The base portion 110 and vertically-oriented socket 140 of the device may be advantageously manufactured as a single piece of resilient polymeric material and, more specifically, manufactured from an injection molded plastic such as polypropylene or polycarbonate-ABS (PCABS). One of ordinary skill in the art will recognize that other materials exhibiting similar characteristics of being lightweight, strong and resilient can be used, such as polyethylene, combinations of polypropylene and polyethylene, and other known materials.

[0026] The present invention has been disclosed in detail in connection with the preferred embodiments. While there are many modifications that can be made without departing from the scope of the present invention, the present invention is defined by the claims that follow.

Claims (19)

1. What is claimed is:

   1. A variable height accessory placement chair for positioning an accessory within a horizontal concrete form, the chair comprising: a base portion having a vertically-oriented, internally-threaded socket that includes at least one vertically-oriented internal detent; and an externally-threaded accessory that mates with the internally-threaded socket for screw-like travel within the socket, with the externally-threaded accessory including at least one longitudinally-interrupted thread section so that upon rotational movement of the accessory within the socket the internal detent cyclically engages the longitudinally-interrupted thread section, whereby screw-like advancement or withdrawal of the accessory within the internally threaded socket positions the accessory at one of a plurality of regularly spaced-apart vertical positions with respect to the base portion.
2. 2. The chair of claim 1, wherein the base portion includes: a plurality of downwardly-oriented legs, and; a plurality of upwardly-oriented arms, with each of the arms connected to one of the plurality of legs, and to others of the pluralities of arms and legs by brace members.
3. 3. The chair of claim 1, wherein the internal thread of the internally-threaded socket is discontinuous.
4. 4. The chair of claim 1, wherein the internal detent is an inwardly-projecting ridge provided on the interior wall of the socket.
5. 5. The chair of claim 1, wherein the internally-threaded socket includes a circumferentially projecting arm partially defining an interior wall of the socket, and a free end of the arm carries the internal detent.
6. 6. The chair of claim 5, wherein the internally-threaded socket includes a radially outwardly-displaced wall section that defines a niche for displacement of the free end and carried internal detent.
7. 7. The chair of claim 1, wherein the longitudinally-interrupted thread section is shaped to correspond to the shape of the internal detent.
8. 8. The chair of claim 7, wherein the longitudinally-interrupted thread section includes a longitudinal groove shaped to releaseably capture the detent.
9. 9. The chair of claim 1, wherein the externally-threaded accessory has a plurality of longitudinally-interrupted thread sections arrayed at equal intervals about the perimeter of the anchorage insert.
10. 10. The chair of claim 9, wherein the externally-threaded accessory has two longitudinally-interrupted thread sections disposed 180 degrees apart about the perimeter of the accessory.
11. 11. The chair of claim 1, further comprising indicia disposed on the externally-threaded accessory so as to display the relative vertical position of the accessory with respect to a device reference point.
12. 12. The chair of claim 11, wherein the base portion includes additional indicia displaying the vertical position of the device reference point.
13. 13. The chair of claim 12, wherein the device reference point is the top of the vertically-oriented, internally-threaded socket.
14. 14. The chair of claim 1, wherein the externally-threaded accessory insert is a unitary plastic insert with a longitudinal shaft having the at least one external thread, the at least one longitudinally-interrupted thread section, and a distal socket for receiving a connector.
15. 15. The chair of claim 14, wherein the distal socket is closed by a locating plug.
16. 16. The chair of claim 1, wherein the externally-threaded accessory insert is a unitary plastic insert with a longitudinal shaft having the at least one external thread, the at least one longitudinally-interrupted thread section, and a distal support platform or saddle for receiving a connector.
17. 17. The chair of claim 1, wherein the externally-threaded accessory further comprises an assembly of: a metal core with a longitudinal shaft having a distal socket; and a plastic sleeve having the at least one external thread and the at least one longitudinally-interrupted thread section, with the plastic sleeve fixedly sheathing the metal core.
18. 18. The chair of claim 17, wherein the plastic sleeve is integrally formed with a plastic distal locating cap that is positioned to cover the distal socket and connected to the sleeve by a thin plastic web.
19. 19. The chair of claim 17, wherein the metal core includes a knurled section that provides an interference fit within the plastic sleeve.