WO2001081234A2

WO2001081234A2 - Lifting system for use in hoisting, particularly heavy cast panels

Info

Publication number: WO2001081234A2
Application number: PCT/US2001/013772
Authority: WO
Inventors: Lawrence Fromelius
Original assignee: Lawrence Fromelius
Priority date: 2000-04-26
Filing date: 2001-04-26
Publication date: 2001-11-01
Also published as: WO2001081234A3; AU2001257402A1

Abstract

One embodiment of the present invention describes a lifting system (20) for hoisting heavy pre-cast panels includes an anchor-lifting device (22) permanently secured within a connection recess formed in the panel, and a connecting apparatus that attaches to the anchor-lifting device. The anchor-lifting device (22) presents a laterally disposed connection pin (38) for attachment to a pair of laterally spaced lifting hooks (52,54) that form the connecting apparatus. Another embodiment of the present invention describes a removable and reusable insert (110) for positioning and supporting a lifting system (200) within a panel to be formed from cast concrete, the insert assembly (110) having a left and right portion (131,133) which are detachably removable from each other, and a lid (112) that is secured over the insert. The lid (112) protects an interior space of the insert assembly.

Description

LIFTING SYSTEM FOR USE IN HOISTING, PARTICULARLY HEAVY CAST PANELS

FIELD OF THE INVENTION

The present invention relates to lifting systems and more particularly to apparatus for lifting pre-cast concrete panels.

BACKGROUND OF THE INVENTION

Prestressed, pre-cast concrete panels enjoy great popularity within the building and construction industry. They currently comprise the major component in the construction of many different kinds of structures, such as office buildings, warehouses, schools, parking decks, retention walls, etc. These pre-cast panels are typically fabricated offsite, that is, they are manufactured at a location other than the actual construction site. Most often the offsite manufacturing facility is a factory especially dedicated to producing concrete panels of various types and configurations. Obviously, the large heavy panels manufactured off-site must be loaded on vehicles and then moved to the construction site. Once at the construction site, the panels must be unloaded and placed in their final position relative to the construction.

FIGS. 1A - 1E describe generally a prestressed concrete panel lifting system. Referring to FIG. 1A, depicted is a commonly-used prestressed concrete panel member 10 (only a portion of which is depicted) of the type to which at least one aspect of the present invention pertains. Prestressed concrete panel member 10 is manufactured such that, during the casting process, anchor plate 11 may be suspended within prestressed concrete panel member 10 in a structurally sound location in order to present cable-lifting holes 15 which will ultimately receive cables for lifting the panel. A plurality of anchor plates 11 are typically positioned throughout a common side of the prestressed concrete panel member 10 because the weight of the concrete necessitates that a number of anchoring plates be used to facilitate a safe and precise transportation of the finished prestressed concrete panel members.

FIGS. 1B - 1D illustrate alternative anchor plates, depicted at reference numerals 12, 13. Moreover, these alternative anchor plates are referenced in U.S. Patent No. 4,627,198 to Francies, the contents of which are hereby incorporated by reference herein in its entirety.

Additionally, in FIG. 1E, cable connection apparatus 14 is illustrated. Cable connection apparatus 14 is used for the quick connection of lifting cables to any one of anchor plates 11 - 13 described above. Of particular note is that cable connection apparatus 14 is capable of repeated use. The various lifting components 11 - 14 comprise a non-exhaustive representation of some of the most popular lifting components being utilized today in the lifting and handling of prestressed concrete panel members. These lifting components 11 - 14 generally provide a secure means of attaching the lifting cables to the prestressed concrete panel member 10, while at the same time providing an adequate degree of manufacturing convenience and flexibility.

However, the prestressed concrete panel member lifting system suffers from a number of drawbacks - most concerning connection recess 17, surrounding anchor plate 11, which can make anchor plate 11 vulnerable to inaccessibility under certain conditions. The foremost problem concerns the blockage of cable-lifting holes 15 that are formed in anchor plate 11 as a result of water that collects and freezes in connection recess 17. During periods of inclement weather, connection recess 17, including cable-lifting holes 15, must either be covered or else be cleared of any frozen material before the lifting cables can be secured within cable-lifting holes 15.

Furthermore, cable connection apparatus 14, usually used with anchor plate 11, represents an additional source of potential malfunction and inconvenience due to its design with a rotating spoon-shaped connecting member. Cable connection apparatuses of this type are described in U.S. Patent No. 4,700,979, to Courtois et a/., the contents of which are hereby incorporated by reference herein in its entirety. In Courtois, the cable connecting member is contained within and made a part of a mechanism comprised of a plurality of moving parts; namely a housing, the cable connecting member and a retaining pin or shaft. The cable connecting member rotates or pivots with respect to the shaft, making the design particularly susceptible to wear, as a result of inadequate lubrication, rust, abuse, ice, snow, etc.

Moreover, although anchor plates 11 , 12, 13 have been used without cable connecting apparatus 14, or some other analogous quick-connect device, one the downsides of anchor plates 11 , 12, 13 is the numerous manufacturing steps that are required in their fabrication, with each step resulting in added costs. Additionally, each anchor plate (e.g., 11 ) is highly specific to only one particular type of prestressed concrete panel member (e.g., 10). In addition, connecting apparatus 14 also requires numerous manufacturing steps.

Although the above discussion centers around permanent anchor plates displaced within prestressed concrete panel members, it has also been a practice to provide inserts that are removably positionable within the prestressed concrete panel members prior to casting, thereby forming holes, depressions or other desired geometrical void configurations within the panels once the concrete has cured. At least one other aspect of the present invention concerns these types of inserts. Similar to the anchor plates, above, inserts have also been used in conjunction with prestressed concrete panel lifting systems. In some cases, the inserts are permanently embedded within the concrete panels. In such applications, the inserts are designed to hold or support the prestressed concrete panel lifting system as the concrete cures and to leave a depression in the cured, prestressed concrete panel member. As described above, this depression facilitates access to the prestressed concrete panel lifting system so that lifting hooks and/or cables can be directly connected to the prestressed concrete panel member without interference from any part of the prestressed concrete panel member.

The process of setting an insert typically involves the use of pins and various angle-iron supports to position the insert in a desired location and to facilitate removal of the insert with a minimum of difficulty. However, several problems exist related to the inserts presently available. Some inserts are not easily positionable, others fail or inadequately protect the prestressed concrete panel lifting system during casting of the concrete panel member; many are difficult to remove after the concrete panel member has cured; and most inserts have a very low level of reusability. The removal and reusability problems are very much related, in that typically, the insert assembly will become bonded to the concrete panel member, making the removal both time-consuming and difficult, and usually destroying the integrity of the insert so that it cannot be used again. Some damage may even result to the concrete panel member itself.

It can be appreciated that, based on the above-described problems, there still exists a long-felt need to provide a prestressed concrete panel lifting system and prestressed concrete panel member insert assembly which can overcome the difficulties and problems mentioned above.

SUMMARY OF THE INVENTION

One embodiment of the present invention provides a prestressed concrete panel lifting system for use with prestressed concrete panel members having at least one surface, which preferably includes a connection recess formed therein. The connection recess may be preferably defined by a bottom surface and at least one side surface. The lifting system comprises a lifting device disposed within the connection recess of the panel member and including at least one connection pin, and a connecting apparatus for engagement with the connection pin, thereby facilitating the lifting of the panel member.

It is another embodiment of the present invention to provide an insert to be used in connection with a prestressed concrete panel lifting system. In one aspect of this embodiment, the insert is to be permanently set within the concrete panel member. In this embodiment, the insert thus comprises a base assembly having an exterior surface defining the shape of a void space to be created. An interior space is also included. The interior space preferably has an access opening, through which the interior space is accessed, and a cover, which closes and protects the interior space. Moreover, the insert is adapted for temporarily receiving a lifting element, such as a hook. It is another embodiment of this aspect of the invention to provide an insert that is non-destructibly removable from the concrete panel member. This reusable insert advantageously includes a pair of movable flaps for assisting removal of the insert after the concrete panel member has cured.

The foregoing and other features and advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed descriptions and drawings are merely illustrative of the invention rather than limiting, the scope of the invention being defined by the appended claims and equivalents thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 A illustrates a perspective view of prior art concerning a prestressed concrete panel member having a connection recess and an anchor plate secured therein;

FIG. 1 B illustrates another perspective view of the anchor plate illustrated in FIG. 1A;

FIG. 1C illustrates another perspective view of another type of anchor plate; FIG. 1 D illustrates another perspective view of still another type of anchor plate;

FIG. 1E illustrates a perspective view of prior art concerning a cable connection apparatus, with an anchor plate secured therein;

FIG. 2 illustrates a perspective view of a prestressed concrete panel lifting system, complete with a prestressed concrete panel member having a connection recess and an anchor plate secured therein, made in accordance with the present invention;

FIG. 3 illustrates a perspective view of the prestressed concrete panel lifting system of the present invention, shown without the prestressed concrete panel member;

FIG. 4 illustrates an exploded view of the prestressed concrete panel lifting system of FIG. 3;

FIGS. 4A and 4B illustrate connection pins used in the prestressed concrete panel lifting system of FIG. 3; FIG. 4C illustrates a coupler member for use in the prestressed concrete panel lifting system of FIG. 3;

FIG. 5 illustrates a plan view of a lifting hook used in the prestressed concrete panel lifting system of FIG. 3;

FIG. 6 illustrates an exploded view of an insert assembly, made in accordance with the present invention;

FIG. 7 illustrates a plan view of the interior of the right portion of the insert assembly of FIG. 6;

FIG. 8 illustrates a plan view of the interior of the left portion of the insert assembly of FIG. 6; FIG. 9 illustrates a top view of both portions of the insert assembly of FIG. 6;

FIG. 10 illustrates a bottom view of the insert assembly of FIG. 6;

FIG. 11 illustrates an isometric view of a prestressed concrete panel lifting system as it would be associated with the insert assembly of FIG. 6, with the lid off for clarity; and FIG. 12 illustrates an isometric view showing the lid of the insert assembly of

FIG. 6, with positioning bars extending through the lid.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

For purposes of promoting and understanding of the principles of the invention, reference will now be made to a preferred embodiment illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, there being contemplated such alterations and modifications of the illustrative device, in such further applications of the principles of the invention as disclosed herein, as would normally occur to one skilled in the art to which the invention pertains.

As mentioned above, one embodiment of the present invention concerns a prestressed concrete panel lifting system for use with a prestressed concrete panel member. FIG. 2 shows exemplary concrete panel member 10' (N.B. Primed reference numerals correspond to the same elements as those disclosed in the prior art Figures) having first pair of opposed surfaces 18A, 18C, and second pair of opposed surfaces 18B, 18D. Each pair of opposed surfaces (18A-18C, 18B-18D) are preferably disposed at right angles to each other. As shown, top surface 18A includes connection recess 17'. Connection recess 17' is preferably elliptically- shaped, although, alternatively, connection recess 17' can be rectangular, square, round or any other desired shape. As shown, concrete panel member 10' includes a longitudinal axis L halving concrete panel member 10'. This dissection necessarily dictates that connection recess 17' has a left half comprising left wall surface 19L and a right half comprising right wall surface 19R. Permanently suspended within concrete panel member 10' and centered within connection recess 17' is lifting device 22 which forms a part of lifting system 20 of the present invention.

Lifting system 20 will now be explained in greater detail below, with reference to FIGS. 3-5. In general, lifting system 20 is generally comprised of lifting device 22 which includes top connection pin 38 and bottom connection pin 42. Attached about top connection pin 38 and disposed on each side of lifting device 22 is connecting apparatus 50. Connecting apparatus 50 is comprised of a left side member 52 and a right side member 54, interconnected by coupler member 70. Each of the side members 52, 54 are rigidly attached together by a stop plate 90, which may be welded to both side members 52, 54. Additionally, coupler member 70 may also be welded to each of the side members 52, 54.

As FIG. 2 depicts, lifting device 22 is suspended within concrete panel member 10', and as FIG. 4 best exemplifies, lifting device 22 is comprised of a generally planar, elongated member made from a piece of steel flat bar stock, having top end region 24 and bottom end region 26 Moreover, each end region 24, 26 includes an identical hole 30, 32. Furthermore, it is seen that each hole 30, 32 is provided with respective connection pin 38, 42, which is inserted into lifting device 22 by interference press fitting each connection pin 38, 42 into a respective hole 30, 32. Each hole 30, 32 and respective connection pin 38, 42 is vertically aligned with respect to the other, and is generally centered between opposing minor sides 25, 27. Moreover, both connection pins 38, 42 have identical connecting pin diameters D. Once each connecting pin 38, 42 is inserted into its respective hole 30, 32 of lifting device 22, each connecting pin 38, 42 has protruding left side and right side portions that project away from opposing major sides 21 , 23.

Either end region 24, 26 may be inserted into concrete panel member 10' during casting, such that one of the ends will project outwardly from the main body of concrete panel member 10' and into connection recess 17'. One important aspect of this embodiment of the present invention is that lifting device 22 is of a symmetrical construction. This construction ensures that, when lifting device 22 is permanently set within concrete panel member 10', a costly mistake will not occur due to the wrong end region being permanently set within concrete panel member 10'. Such was a problem with prior art anchoring devices. In line with the symmetrical construction of lifting device 22, the preferred embodiment also includes top and bottom connection pins 38, 42. Alternatively, it should be realized that lifting device 22 may be attached to concrete panel member 10' by other methods rather than solely embedding lifting device 22 within concrete panel member 10'. Also seen in FIGS. 3 and 4 is connecting apparatus 50, which represents another member of lifting system 20 of this embodiment of the present invention. FIG. 3 shows connecting apparatus 50 engaged with top connecting pin 38, straddling both major sides 21 , 23 of lifting device 22. Because each side member 52, 54 is identical to the other, only the details of right side member 54 will be explained herein.

As seen more clearly in FIG. 5, right side member 54 is a generally rectangular-shaped member having outside surface 58 and inside surface 60. Moreover, right side member 54 includes top left region 51 that is configured with a rounded corner, top right region 53 having a rounded corner, bottom right region 57 also having a rounded corner, and a bottom left region 59. Bottom left region 59 includes diagonally-disposed engagement channel 61 which forms lifting arm 62. Lifting arm 62 extends in a direction away from a lateral line of right side member 54 and parallel to engagement channel 61. The boundaries of engagement channel 61 define long surface 63, short surface 65 and radial surface 67, which is located at the apex of the long and short surfaces 63, 65. When connecting apparatus 50 is mated about lifting device 22, engagement channel 61 is closely fitted about connection pin 38, the arcuate curvature of radial surface 67 being preferably sized to closely match the diameter of connection pin 38, and allow a snug fit. That is, the width of engagement channel 61 , which roughly corresponds to the distance between surfaces 63, 65, is slightly larger than pin diameter D. Right side member 54 is preferably formed by using a plasma cutter to form the peripheral edges and comers. However, engagement channel 61, as well as connection pin 38, are preferably machined so that very tight tolerances between engagement channel 61 and connection pin 38 are maintained. In this way, right side member 54 will not be capable of laterally rocking on the connection pin 38 during lifting of the concrete panel member 10'. As a matter of integrity, should the tolerances begin to grow, connecting apparatus 50 will be prone to laterally rocking on connection pin 38, as well as to an easygoing rotation around connection pin 38, signifying that connecting apparatus 50 should be discarded. It can also be seen that lifting arm 62 includes outside surface 64 which assists in preventing rotational movement around connection pin 38 when concrete panel member 10' is being lifted. The details of that function will be explained later herein. Right side member 54 also includes hole

69 near top right region 53, hole 69 being defined by hole boundary 68. FIG. 4C shows coupler member 70 in greater detail. In use, coupler member

70 maintains a lateral spacing between each of the side members 52, 54 in order for connection apparatus 50 to accept lifting device 22 therebetween when connecting apparatus 50 is secured about the left and right sides of connection pin 38. Coupler 70 has outside surface 72 and interior space 75 which defines an interior surface 71. Interior space 75 extends completely through coupler member 70 from first end region 74 to opposing second end region 76. Instead of each end region 74, 76 terminating with a planar, or truncated, surface, each end region 74, 76 is provided with flared transition surface 78, thereby providing a smooth surface area between inside surface 71 and outside surface 72. The function of the flared transition surface 78 is to provide a greater force-distribution surface area for a lifting cable which is inserted through interior space 75 when concrete panel member 10' is to be lifted. It should be understood by viewing FIG. 3 that when each side member 52, 54 is connected to coupler member 70, end regions 74, 76 do not project beyond each side member. Returning to FIG. 4C, coupler member 70 also includes annular upraised region 80 disposed about the midpoint between ends 74, 76. The longitudinal extent of annular upraised region 80 determines the spacing between each side member 52, 54. Furthermore, this longitudinal extent can be made to vary in direct relation to the chosen thickness of the flat bar stock that is used for constructing lifting device 22. The ends of annular upraised region 80 form shoulder 82 on the side of the coupler associated with first end 74 and shoulder 84 on the side associated with opposing second end 76. When each side member 52, 54 is slid over coupler member 70 (which, conversely, is received in hole 69), outside surface 72 is in close tolerance to hole boundary 68 of hole 69. Furthermore, shoulders 82, 84 present a stop for each side member 52, 54. As a result, inside surface 60 of right side member 54 abuts against a respective shoulder 82. Hole 69 of right side member 54, as well as coupler member 70, are machined in order to maintain very close tolerances in order to avoid creating load imbalances during lifting, and hence, unbalanced stressing within each hook. Although not shown or numbered, a similar process occurs with respect to left side member 52.

As best seen in FIGS. 3 and 4, right side member 54 is joined to stop plate 90 along back surface 66. Front face 92 of stop plate 90 is abutted against back surface 66, and a weldment bead is applied along an edge surface of stop plate 90 and along back surface 66, thereby securing stop plate 90 to right side member 54. As a result, right side member 54 cannot rotate about coupler member 70 once stop plate 90 is welded thereto. Corner regions 91, 93 do not extend beyond outside surface 58 of right side member 54 once stop plate 90 is attached. All components of the present invention are preferably made of cold rolled 4140 steel, although other types can be used as long as they can handle the stresses experienced in the particular application.

In operation, when connecting apparatus 50 is engaged with lifting device 22 within connection recess 17', outside surface 64 of lifting arm 62 on right side member 54 will preferably rest against at least the portion of the wall surface defining connection recess 17'. Likewise, each corner region 91 , 93 of stop plate 90 will also contact at least a portion of the surface defining connection recess 17'. This aspect of this embodiment of the present invention becomes very important during a lifting operation of concrete panel member 10' because, typically, once concrete panel member 10' is lifted, it will have a tendency to rotate along longitudinal axis L. Because the present embodiment provides engineered right side member 54, as well as stop plate 90, concrete panel member 10' will not be able to rotate as readily about longitudinal axis L because stop plate 90, in conjunction with the outside surface of lifting arm 62, will contact the inside wall surfaces forming connection recess 17', thereby opposing rotational movement. This feature is seen as an important safety-related improvement over prior art devices which did not prevent rotational movement of concrete panel member during the lifting process. Another important aspect of this embodiment concerns flared transitional surface 78 on each end of coupler member 70. In this respect, it should be understood that because flared transitional surface 78 is provided, the lifting cable which is inserted through interior space 75 does not rest against a corner and create a point-loaded condition. Rather, the smooth transition between inside surface 71 and outside surface 72 of coupler member 70 provides a distributed lifting load across a large, flared transitional surface 78, thereby reducing the wear on the lifting cable, while simultaneously reducing stress concentration points on the cable and coupler. As noted, this embodiment of the present invention has found particular application in lifting pre-cast concrete panel members 10'. It could readily be adapted to other constructs and objects to be lifted. Furthermore, while lifting device 22 is described as permanently affixed within a recess in the preferred embodiment, it need not be, although this is not considered most advantageous. Moreover, lifting device 22 could extend beyond the adjacent surface of the object it is to lift, although once again, this is presently not considered as most desirable in the described environment.

Referring to FIGS. 6-9, a preferred embodiment of an insert assembly is identified at 110. Insert assembly 110 generally comprises lid 112 and cooperating base assembly 130. Base assembly 130 is formed of first or right portion 131 , and second or left portion 133. Both portions 131 , 133 are connected together by a snap-fit connection, as will be explained later herein. Both portions 131 , 133 are essentially mirror images to the other, except for two variations which relate to how they are joined together, and which will be specifically highlighted. Therefore, only right portion 131 will be explained in greater detail, and it should be understood that like elements will also be referred to with like references characters for both portions.

As seen, right portion 131 is comprised of vertical wall 134 having inside surface 136 and outside surface 138 and top edge surface 140. Vertical wall 134 is integrally connected to arcuate wall 142 which is disposed perpendicular to vertical wall 134. Arcuate wall 142 includes inside end 144, outside end 146, and top edge surface 148. Arcuate wall 142 and vertical wall 134 share integral edge 150 which is the connection point between the two walls. Outside end 146 of arcuate wall 142 includes joining edge 152 which is formed by undercut 156 extending along entire outside end 146, thus creating lip surface 158. Right portion 131 also includes laterally spaced cylindrical pin receptor housings 160 which are essentially solid, cylindrical members having blind bore 162 formed therein. Each cylindrical pin receptor housing extends from the edge of lip surface 158 to inside surface 136 of wall 134, terminating at integral edge 150. One difference between left portion 131 and right portion 133 involves cylindrical pin receptor housing 160. On left portion 133, instead of cylindrical pin receptor housings 160 being provided with blind bores, the cylindrical pin receptor housings are solid and they further include projecting cylindrical protuberance or pin 165. Respective cylindrical pins 165 are all identical and of a diametric size which is readily received within a respective blind bore 162 on right portion 131. Right and left portions 131 , 133 each include vertically disposed stiffeners

164 that are opposed from each other when the two portions are connected together. Centered between each portion's respective stiffener 164 is arcuate bracket 166 that is formed from semi-circular wall 168 which has interior surface 169 and exterior surface 171. Semi-circular wall 168 forms opening 170 that faces arcuate wall 142. Vertical wall 134 also includes indentation 174 formed into inside surface 136. Indentation 174 has vertical height 175 and horizontal extent 177, wherein horizontal extent 177 is approximately equivalent to an outer diameter of arcuate bracket 166. Indentation 174 is provided to facilitate insertion and removal of a pin element that forms part of a lifting system which is to be embedded in the concrete; this aspect will be explained later. Arcuate wall 142 also includes movable flap 178, coextensive with indentation 174, particularly along horizontal extent 177. Movable flap 178 is formed by a pair of laterally spaced, V-shaped indentations 180 that are stamped into inside surface 144 of arcuate wall 142. Movable flap 178 has horizontal extent 182 that is identical or substantially equivalent to horizontal extent 177 of indentation 174. Right portion 131 also includes recess 184 formed in arcuate wall 142. Recess 184 is defined by short side walls 186 and interconnecting long side wall 188. Likewise, left portion 130 will include an identical recess. When left and right portions 131, 133 are connected together, they will form rectangular opening 190 which is centered within base assembly 130. One other noteworthy difference between first portion 131 and second portion

133 is that first or right portion 131 is formed with undercut 156 in the face of inside surface 144 on arcuate wall 142 to create bottom lip 158 having lip surface 158A (e.g., FIG. 7). However, second or left portion 133 also includes matching undercut 156', but undercut 156' is formed into outside surface 146 of arcuate wall 142 of that portion (e.g., FIG. 8), thereby creating top lip 158' having lip surface 158'B. When left and right portions 131 and 133 are to be joined together, cylindrical pins 165 are inserted into blind bores 162, and lip surfaces 158A and 158'B complementarily superimpose such that top and bottom lips 158 and 158' form a connection joint. Left and right portions 131, 133, each include identical peripheral ledge 198 (FIG. 9) that is located adjacent top edge 140 and which extends or projects away from respective outside surfaces 138, 146 of walls 134, 142. When the two sections are joined together, peripheral ledge 198 extends continuously about the perimeter of the base assembly to accept lid 112 in a snap-fit fashion.

Turning attention to FIG. 10, lid 112 is illustrated, and it generally comprises a rectangularly configured member having top and bottom planar wall surface 114T, 114B, respectively, and downwardly projecting perimeter rim 116 that is disposed perpendicular to surface 114B. Bottom surface 114B is shown with lip 116 projecting out the plane of the paper towards a viewer in FIG. 10. Lid 112 includes first circular hole 118 that is defined by edge surface 119, and second circular hole 120 that is defined by edge surface 121. These are finger (or pry) holes for the cover. Disposed between each of holes 118, 120, are a pair of rectangular slots 122, 124 that are arranged parallel to each other. As seen, slot 122 is delimited by surface 123, while slot 124 is delimited by surface 125. Perimeter rim 116 also includes small lip 127 integrally formed therein, which projects towards the interior of the lid. Small lip 127 snaps underneath peripheral ledge 198 formed around the periphery of base assembly 130 when the lid is connected to the base.

Turning attention now to FIGS. 11 and 12, insert assembly 110 will be described with respect to its complimentary use with lifting system assembly 200. Preferably, lifting system assembly 200 may be similar to the prestressed concrete panel lifting system, described above. As seen, lifting system assembly 120 includes rectangular member 202 that is formed from steel flat stock and which is situated within a cast concrete member (not shown) at least partially. Rectangular member 202 is referred to as an anchor-lifting device, and it includes major opposed surfaces 204 and minor opposed surfaces 206 (only one shown), along with the perpendicularly arranged lifting pin or rod 208 extending therethrough. Lifting pin 208 is of a diameter which is substantially the same diameter of arcuate bracket 166 which is essentially defined by interior surface 169 of wall 168.

Lifting system assembly 200 is initially inserted within the base assembly such that lifting pin 208 is in contact against interior surface 169 of arcuate bracket 166. Furthermore, rectangular opening 190 that is formed in base assembly 130 receives rectangular flat stock member 202 such that major surfaces 204 contact against each of long side walls 188, while minor surfaces 206 of rectangular flat stock member 202 contact against each of short side walls 186. Positioning plates 210, 212 are used in certain applications where base assembly 130 could be subject to movement while the concrete is setting up. Plates 210, 212 are formed with holes 214, 216 and 218, which are respectively delimited by edge surfaces 215, 217 and 219. The positioning plates each include major surfaces 220 and minor surfaces 222. Each plate 210 and 212 is inserted within respective rectangularly-shaped slot 122 and 124 formed in lid 112 such that major and minor surfaces 220, 222 contact surfaces 123, 125 which define the rectangular slots. From holes 214, 216 and 218 that are provided, one of them is chosen so that the positioning plates are inserted over lifting pin 208 by insertion into the chosen hole. This is done prior to the lifting pin being inserted into arcuate bracket 166. When the positioning plates are properly installed, lid 112 is snap fitted onto base

Claims

assembly 130. The entire insert assembly 110 and lifting system assembly 200 is then ready for inclusion into a concrete panel member (not shown) that is about to be cast. The other two remaining holes 216 and 218 on each of positioning plates 210, 212, are provided to receive a rather substantial bar member (not shown) which is used to hold insert assembly 110 in a fixed position with respect to the mold of the precast panel member. The bar would extend across the frame of the mold so that insert assembly 110 is held in a fixed position during the pouring of the concrete into the mold, such as when the insert is used along a side of the concrete form (as contrasted with simply resting on the top). By supporting the insert assembly in a fixed position, the lifting system assembly is also held fixed since it is coupled to the insert at arcuate brackets 166.Insert assembly 110 is preferably formed of a material which does not allow the concrete composition to adhere to outside surfaces 138, 146 of base assembly 130, such as a smooth-surfaced high-impact rigid plastic. Thus, after the concrete has been poured into the mold, it can be appreciated that lid 112 protects lifting system assembly 200 and prevents concrete from filling the interior space of base assembly 130. Once the concrete has set and cured, lid 112 is removed and retained for future use. Secondly, flaps 178 are pried upwards to free them in order to expose the set concrete that is now formed around the insert. Flaps 178 are graspable, and can in some instances be used to pull the insert free. Otherwise, a pry bar can be inserted through the open flaps 178 to pry the entire base assembly 130 from the precast concrete member without destroying insert assembly 110. Thus, it is a great cost savings that the lid and base assembly can be used again in another casting. In fact, the present invention allows lid 112 to be used over almost indefinitely, while base assembly 130 has been successfully tested in at least ten castings before reaching a state where it should be discarded.While the apparatus and method herein disclosed form a preferred embodiment of this invention, this invention is not limited to those specific apparatus and methods, and changes can be made therein without departing from the scope of this invention which is defined in the appended claims. WHAT IS CLAIMED IS:

1. A lifting system for use in pre-cast panels having an end surface which includes a connection recess formed therein, the recess defined by a bottom surface and a least one side surface, comprising: an anchor-lifting device permanently suspended in the pre-cast panel within the connection recess, the anchor-lifting device including at least one connection pin; and a connecting apparatus for engagement with the connection pin to lift the pre-cast panel.

2. The lifting system of claim 1 , wherein the anchor-lifting device is comprised of a piece of flat bar stock having a top and bottom end, and a pair of major and minor sides, each of the minor sides disposed at perpendiculars to both of the major sides, at least one end of the anchor-lifting device including a connection pin mounted thereto.

3. The lifting system of claim 2, wherein the connection pin has a portion projecting away from each major side of the anchor-lifting device, each portion being of an identical extent.

4. The lifting system of claim 1 , wherein the connection apparatus is comprised of a lifting hook having an engagement channel which defines a lifting arm, the engagement channel receiving at least one connection pin when engaged therewith, the lifting arm holding the at least one pin during a lifting of the pre-cast panel.

5. The lifting system of claim 4, wherein the lifting hook is comprised of two laterally-separated hooks, each hook joined together by a shared coupler and stop plate.

6. The lifting system of claim 5, wherein each hook includes an identical engagement channel, the engagement channel having a width that is about equal to the diameter of the connection pin that is received therein.

7. The lifting system of claim 6, wherein the lifting arm of each hook is disposed at an acute angle respective the longitudinal axis of the cast panel when inserted in the connection recess, and where an outside surface of each respective arm contacts at least one surface defining the connection recess.

8. The lifting system of claim 5, wherein the coupler member has an outside surface, a pair of ends and an interval cavity extending therebetween, each end having a flared transitional surface between the inside and outside surfaces.

9. The lifting system of claim 8, wherein each hook has an inside and outside surface and each coupling end is coextensive with a respective outside surface on each hook.

10. The lifting system of claim 5, wherein the stop plate is welded across each hook on a respective back side, near a bottom portion of each hook.

11. A method of lifting a pre-cast panel member having a top surface which includes a connection recess formed therein and a longitudinal axis which dissects the recess, the recess defined by a bottom surface and at least one interconnecting and continuous side surface, comprising: providing a permanently suspended anchor-lifting device within the connection recess of the pre-cast panel, the device including at least one connection pin disposed above a bottom surface of the recess; attaching a connecting apparatus to the at least one connection pin such that the apparatus is prevented from rotating within the connection recess during lifting thereof; and lifting the connecting apparatus in order to lift the pre-cast panel member.

12. The method of claim 11 , wherein the connection pin is disposed transversely to the longitudinal axis, and extends through the anchor-lifting device to form a left and a right pin portion on opposite sides of the anchor-lifting device.

13. The method of claim 12, wherein the connecting apparatus is a hook comprised of a pair of identical lifting hooks laterally spaced from the other by a coupler, each hook including an identical engagement channel for receiving one of a left and a right pin portion therein.

14. A connecting apparatus for use with lifting a heavy pre-cast panel member, the panel member having a top surface which includes a connection recess formed therein, the recess defined by a bottom wall surface and at least one interconnecting side wall surface, the recess generally centered along a longitudinal axis of the top surface and including therein, an upstanding anchor-lifting device permanently embedded in the panel member, the anchor-lifting device presenting at least one connection pin transversely disposed to the longitudinal axis, the connecting apparatus comprising: a first and a second identical lifting hook, each hook having a engagement channel which defines a lifting arm formed at one, lower corner thereof, and a hole formed at an upper, diagonally opposite corner; and a coupler having a cylindrical outside surface, wherein the coupler is inserted into each of the holes formed into the hooks, the coupler having a first and a second end and a centrally disposed interior space extending between the ends, each end having a flared transitional surface formed between the inside and outside surfaces, which transitional surfaces are coextensive with an outside surface of each hook.

15. The connecting apparatus of claim 14, wherein the coupler includes an upraised land formed about a midpoint between the ends, the land having a predetermined longitudinal extent which corresponds to a lateral spacing between the hooks.

16. The connecting apparatus of claim 15, wherein the land presents a pair of shoulders, each shoulder contacting a respective inside surface of each hook when the hooks are connected to the coupler by sliding each end of the coupler through the hole formed in the hook.

17. The connecting apparatus of claim 14, wherein the engagement channel is defined by a long surface and an opposed short surface, a distance between surfaces being about the same as a diameter of the connection pin.

18. The connecting apparatus of claim 14, wherein the lifting arm upwardly extends towarrddss tthhee ttoopp surface of the panel when the hooks are secured about the connection pins.

19. The connecting apparatus of claim 14, further including a shared stop plate attached to a back side of each hook, the stop plate having a pair of opposing corners, each of which does not project beyond an outside surface of each hook.

20. The connecting apparatus of claim 19, wherein the corners of the stop plate contact a wall surface of the recess connection when the connecting apparatus is secured to the connection pins.

21. A lifting system for use in lifting an object, comprising: an anchor-lifting device attached to the object, the anchor-lifting device including at least one connection pin; and a connecting apparatus adapted to engage the connection pin and lift the object.

22. The lifting system of claim 21 , wherein the anchor-lifting device is a planar member having opposed sides and wherein the at least one connection pin is perpendicularly mounted to at least one of the sides.

23. The lifting system of claim 22, wherein the planar member has a top and a bottom end and a hole formed at the top end, and wherein the connection pin is interference-fitted with the top hole.

24. The lifting system of claim 23, wherein the connection pin is comprised of a portion projecting away from each of the sides of the planar member, each portion being of an identical extent.

25. The lifting system of claim 24, wherein the planar member includes a hole formed in the second end and a second pin is interference-fitted within the second hole, the top and bottom holes in vertical alignment with each other.

26. The lifting system of claim 24, wherein the connection apparatus is comprised of lifting hook having an engagement channel which defines a lifting arm, the engagement channel receiving the connection pin therein when the hook is engaged with the anchor-lifting device.

27. The lifting system of claim 26, wherein the lifting hook is comprised of two identical, laterally-separated hooks, each hook joined together by a shared coupler and stop plate, wherein the engagement channel of each hook has a width that is about equal to the diameter of the portion of the connection pin that is received therein.

28. A hook for lifting a workpiece having a pair of laterally spaced sides and a connection pin extending between the sides, comprising: two identical, laterally-separated hooks, each hook joined together such that the workpiece is received between the hooks during lifting; a coupler attached to each hook for maintaining the hooks laterally separated.

29. The hook of claim 28, wherein each hook includes an identical engagement channel for receiving the connection pin therein during lifting, each engagement channel having a width that is about equal to a diameter of the connection pin.

30. The hook of claim 29, wherein each hook has a corresponding top and bottom end and further includes a hole formed therein near the top of the hook, the coupler received within each hole.

31. The lifting system of claim 30, wherein a shared stop plate is welded across each hook on a respective bottom and back side thereof.

32. The lifting system of claim 30, wherein the coupler has an outside surface, a pair of ends and an internal cavity extending therebetween, each end having a flared transitional surface between the inside and outside surfaces.

33. The lifting system of claim 32, wherein each hook has an inside and outside surface and each coupling end is coextensive with a respective outside surface on each hook.

34. An anchor-lifting device for use in a lifting system used for lifting an object, comprising: a base member having an opposed pair of sides and attachable to the object to be lifted; at least one connection pin, wherein the at least one connection pin is perpendicularly mounted to at least one of the sides of the base member.

35. The anchor-lifting device of claim 34, wherein the base member is comprised of a piece of flat bar stock having a top and bottom end and a hole formed in the top end, the connection pin interference-fitted within the hole.

36. The anchor-lifting device of claim 35, wherein the connection pin has a portion projecting away from each side of the base member, each portion being of an identical extent.

37. The anchor-lifting device of claim 36, wherein the base member includes a hole formed in the second end and a second pin is interference-fitted within the second hole, the top and bottom holes vertically aligned, wherein the device is symmetrically constructed.

38. An insert for placement within a mold used for forming a void space in a cast material, comprising: a base assembly having an outside surface which defines a configuration to be molded into the cast material, said outside surface being comprised of another material which is non-destructively separable from the cast material when the cast material is set, the base assembly further having an interior space defined therein and an opening through the outside surface extending into the interior space; a lid that removably attaches to the base assembly, the lid protecting the interior space of the base assembly from entry of the cast material.

39. The insert of claim 38, wherein the base assembly has a left and a right portion that detachably connect to each other, the left portion and right portion including respective arcuate wall brackets integrally formed therein for receiving a pin of a lifting hook assembly that is to be set into a panel.

40. The insert of claim 39, wherein the lid snap-fits onto a peripheral ledge formed in the base assembly.

41. The insert of claim 39, wherein the base assembly includes a pair of movable flaps which move inboard relative to the interior space for assisting removal of the insert from the panel.

42. The insert of claim 40, wherein the lid is provided with a pair of spaced slots in communication with the interior spaces, each slot receiving a positioning member therethrough when the insert is to be set in the panel prior to casting.

43. The insert of claim 38, wherein the material to be cast is concrete.

44. An insert and lifting hook system for use in casting precast concrete panels, comprising: <_> a base assembly that defines a configuration to be molded into a panel to be cast, the base assembly having an interior space and a bottom opening; a lifting hook assembly having a part received within the base assembly through the bottom opening; a lid attached to the base assembly protecting the interior space of the insert and the lifting hook assembly from entry of concrete during casting, said lid having at least one slot defined therein adapted to receive a positioning member for orienting said base assembly relative to said lifting hook assembly.

45. An insert for creating a void space within a settable material which will form a solid product when set, with the void space surrounding an element embedded in the settable material, comprising: a base member having an exterior surface defining the shape of the void space to be created within the settable material, and an interior space defined within said base member, said base member further having (i) an element opening defined in said exterior surface adapted to receive the element therethrough with the element extending into said interior space, and (ii) an access opening defined in said exterior surface and through which said interior space is accessed to reach the element when the element is extending into said interior space; a cover over said access opening, said cover having a closed position wherein said interior space is generally inaccessible and an open position wherein said interior space is accessible.

46. The insert of claim 45 wherein said base member is reusable, being formed of with an exterior surface which is non-destructibly disengageable from the solid product formed from the settable material.

47. The insert of claim 45 wherein said base member is formed of substance which does not fixedly bond with the settable material along said exterior surface, said insert being non-destructibly removable from the solid product formed from the settable material.

48. The insert of claim 45 wherein the element is part of a lifting assembly which includes a first lifting piece having an elongated portion embedded within the settable material and another portion of said first lifting piece extending into said interior space, and a second lifting piece extending generally perpendicular to a longitudinal axis of said first lifting piece, said base member further including a first receptacle on a first interior sidewall of said interior space within which at least a portion of said second lifting piece is received.

49. The insert of claim 48 wherein said second lifting piece is a rod having a radial diameter, said first receptacle having an arcuate shape yielding a concavity with a radius of curvature adapted to receive said rod therein.

50. The insert of claim 49 wherein a second receptacle is provided on an interior sidewall opposite to said first interior sidewall, said second receptacle also having an arcuate shape yielding a concavity with a radius of curvature adapted to receive said rod therein, said rod extending generally perpendicularly outboard from respective sides of said first lifting piece.

51. The insert of claim 45 wherein said cover further includes at least one slot defined therein, said slot adapted to receive a positioner used to locate said base in place relative to the settable material.

52. The insert of claim 51 wherein said positioner extends into said interior space through said slot and releasably engages an anchor point provided within said interior space.

53. The insert of claim 49 wherein said cover further includes at least one slot defined therein, said slot adapted to receive a positioner used to locate said base member in place relative to the settable material, said positioner extending into said interior space through said slot and releasably engaging said rod.

54. The insert of claim 45 wherein said exterior surface is defined in part by a base member sidewall which also defines in part said interior space, said base member sidewall further having a flap formed therein, said flap being hingedly connected to said base member sidewall and movable relative thereto into said interior space and said flap is adapted to yield a graspable flap which is accessible through said access opening to facilitate removal of said base member from the solid product.

55. The insert of claim 45 wherein the material is concrete and the element is part of a lifting assembly, said insert yielding a void space around at least a piece of the lifting assembly which is below the level of an exterior surface of the concrete, said cover preventing substantial ingress of concrete into said interior space in formation of the solid product.

56. The insert of claim 49 wherein the material is concrete, said insert yielding a void space around said first and second lifting pieces which is below the level of an exterior surface of the concrete, said cover preventing substantial ingress of concrete into said interior space in formation of the solid product.