LOAD-ENGAGING DEVICE FOR HOISTING CONCRETE BUILDING ELEMENTS

Abstract: With a view to being placed about the head (2) on a lifting bolt (2, 3) placed axially in a hemispherical recess (4) in a concrete building element (5), the load-engaging element (1) comprises a body (6) that is symmetrical about a central plane and shaped like a central segment of a sphere, said body (6) having a roughly radially protruding arm (7) for turning the body (6) in the recess (4), said arm (7) having an abutment surface (8) abutting firmly against the surface (9) of the concrete element (5), when the latter is being hoisted. The body (6) comprises an inverted T-shaped slot (10) extending through approximately 180 degrees along the spherical surface of the body and adapted to receive the head (2) of the lifting bolt (2, 3) by means of a cut-out (11), through which the bolt head (2) may be inserted in and removed from the slot (10). A central slot (12) extending approximately diametrically through the body (6) opens into the inverted T-shaped slot (10), and a bolt (14) placed eccentrically about the abutment surface (8) extends across the central slot (12) and is secured in bores in the body (6). The end link (17) of a connecting means in the form of a chain (16) is placed in the central slot (12) and retained by the bolt (14). When the concrete element (5) is being lifted, the pull in the chain (16) will exert a turning moment on the body (6), causing the abutment surface (8) on the arm (7) to be pressed against the surface (9) of the concrete element (5), so that the body (6) cannot inadvertently be turned to the position, in which the cut-out (11) is positioned about the head (2) of the lifting bolt (2, 3), allowing the latter to be released from the load-engaging device (1).

Description: LOAD-ENGAGING DEVICE FOR HOISTING CONCRETE BUILDING ELEMENTS TECHNICAL FIELD The invention relates to a load-engaging device of the kind set forth in the preamble of claim 1. BACKGROUND ART A device of the kind referred to above is described in DE Patent Publications Nos. 3.012.278 and 3.012.280, relating to an apparatus for suspending a concrete body in a hoisting apparatus. In this apparatus, the load-engaging tackle comprises a suspending shackle with a link eye extend¬ ing through a link bore through the middle of the body, and an inadvertent release of the head of the lifting bolt is prevented by the manipulating arm abutting against a rib in this suspending shackle, if the situation entails a risk of such a release. DISCLOSURE OF THE INVENTION It is the object of the invention to provide a load- engaging device of the kind referred to initially that allows forces to be exerted on the lifting bolt at an oblique angle of e.g. 45 degrees with the surface of the concrete element without risk of the head of the lifting bolt being released, said device at the same time being capable of use with var¬ ious hoisting-connecting means. This object is achieved with a device, according to the invention characterized by the features set forth in the characterizing clause of claim 1. Since the load-engaging device according to the in¬ vention after having been attached to the lifting bolt, but before the lifting of the concrete element, is freely rotat- able about this bolt in the hemispherical recess, it is always possible, with a view to oblique forces being exerted subsequently on the device, to turn the manipulating arm so as to make it face in the direction, from which the force is exerted, and since the force is transmitted to the bolt situated eccentrically relative to the abutment surface of the.manipulating arm, this abutment surface will be pressed aga ast the surface of the concrete element, so that it is no longer possible to turn the body in the recess to that position, in which the head of the lifting bolt can be re¬ leased. At the same time, it is possible to attach various hoisting-connecting means to the bolt extending through the central slot in the body. If the load-engaging device according to the invention constitutes a part of a ready-made hoisting sling comprising a chain, the embodiment set forth in claim 2 can be useful. If the connecting means is a hook or a shackle, the embodiment according to claim 3 can be useful. BRIEF DESCRIPTION OF THE DRAWINGS In the following detailed portion of the present description, the invention will be explained in more detail with reference to the exemplary embodiment of a load-engaging device according to the invention shown in the drawings, in which Figure 1 shows the load-engaging device in section along the line I-I in Figure 2a, Figure 2a shows the device as viewed in the direction of the arrow II in Figure 1, Figure 2b shows the device as viewed in the direction of the arrow III in Figure 1, Figure 3 shows the device being attached to a lifting bolt, Figure 4 in the same manner as in Figure 1 shows a chain secured to the device, and Figure 5 in the same manner as in Figures 1 and 3 shows the load-engaging device connected to the eye of a shackle through a universal joint. DESCRIPTION OF THE PREFERRED EMBODIMENT Figures 1, 3, and 4 show a load-engaging device ac¬ cording to the invention, generally designated by the refer¬ ence numeral 1, as shown in the drawing placed in a securing manner about the head 2 and a part of the stem 3 on a lifting bolt embedded in a hemispherical recess 4 in a concrete building element 5, of which only a part is shown. The device 1 comprises a body 6 symmetrical about a central plane corresponding to the sectional line I-I in Figure 2a, in the form of a central segment of a sphere with a slightly smaller diameter than the hemispherical recess 4, having a protruding manipulating arm 7 with an abutment surface 8 extending radially relative to the body 6, said surface 8 being adapted to abut against the surface 9 of the concrete element 5, when the device 1 is placed in a securing manner on the head 2 of the lifting bolt 2,3. When the device 1 is to be placed about the head 2 on a lifting bolt 2,3, the arm 7 is used for turning the body 6 relative to the head 2 to the position shown in Figure 3. The body 6 comprises an inverted T-shaped slot 10 extending along its spherical surface and adapted to receive the head 2 and a part of the stem 3 of the lifting bolt. In the securing position for the lifting bolt 2,3, its stem 3 forms an angle of about 90 degrees with the abutment surface 8 on the arm 7 abutting against the surface 9 on the concrete element 5, and the head 2 on the lifting bolt is positioned at the inner, closed end of the T-slot 10. At the other end of the latter, there is a cut-out 11 making it possible to introduce the head 2 of the lifting bolt in the part of the T-slot 10 corresponding to the crossbeam in the T, a part of the stem 3 of the lifting bolt being introduced in the part of the slot 10 corresponding to the vertical beam in the T, when the load-engaging device 1 is in the position shown in Figure 3 in the hemispherical recess 4 in the con- crete element 5. In the same position, the lifting bolt 2,3 may be released from the load-engaging device 1. A slot 12 for receiving a chosen connecting means in a manner to be explained below extends centrally and sub¬ stantially diametrically in the body 6 and opens into the T-slot 10. Mutually aligned bores 13, situated eccentrically in the body 6 and diametrically opposite to the retaining position for the lifting bolt 2,3 shown in Figure 1, i.e. penetrating the body and the slot 12 at right angles in a diametral plane through the body 6 at right angles to the abutment surface on the manipulating arm 7, these bores 13 are adapted to receive a bolt 14 for securing the connection means, the bolt 14 being removably secured in the body 6 by means of a pin (not shown) . Finally, the body 6 comprises an incision 15 above and parallel to the abutment surface 8, the function of which will be explained below with refer- ence to Figure 5. Figure 4 shows the load-engaging device according to the invention in operation with a chain 16 as connecting means, the chain 16 being secured to the body 6 by having its end link 17 placed within the slot 10, the bolt 14 having subsequently been inserted through this link 17. When, as shown in Figure 4, there is an oblique pull in the chain 16, this pull will exert a turning moment on the body 6, causing the abutment surface 8 on the arm 7 to be pressed firmly against the surface 9 on the concrete element 5. Thus, there is no possibility, when the concrete element 5 is being lifted, that the body 6 can turn away from the position shown in Figure 4 to the release position shown in Figure 3. Figure 5 shows an embodiment of the load-engaging device according to the invention intended for use with connecting means like a hook or a shackle (not shown) . In this embodiment, a lug 18 on a universal joint generally designated 19 is introduced in the slot 12 in the body 6 and retained therein by having the bolt 14 extending through a bore in the lug 18. Transversely to the lug 18, the uni¬ versal joint 19 comprises a fork, through the legs 20 of which there are mutually aligned bores receiving a bolt 21, likewise extending through a bore in a lug 22 having an eye 23 for receiving a shackle or a hook. As shown, the incision 15 allows the universal joint 19 and with it the lug 22 and the eye 23 to be turned about the bolt 14 to a position, in which they form an angle of approximately 45 degrees with the surface 9 of the concrete element 5. When the hook or the shackle as shown in Figure 5 pull obliquely upwards on the eye 23, the same force relationships apply as explained above with reference to Figure 4, and the body 6 cannot turn away from the retaining position shown to the release position for the head 2 on the lifting bolt 2,3 shown in Figure 3. LIST OF PARTS 10 15 20 25 30

Claims: C L A I M S : 1. Load-engaging device (1) to be placed securingly about the head (2) on a lifting bolt (2,3) embedded prefer¬ ably axially in a hemispherical recess (-f.l in a concrete building element (5) with a view to hoisting the latter with the aid of a hoisting apparatus, such as a crane, and comprising a body (6) that is symmetrical about a central plane (I-I) and shaped substantially like a central segment of a sphere limited by parallel segmenting planes and fitting into said hemispherical recess (4) , said body (6) comprising a protruding manipulating arm (7) with an abutment surface (8) extending substantially radially relative to the body (6) , the latter also comprising an inverted T-shaped slot (10) extending through approximately 180 degrees along the spherical surface of the body (6) and adapted to receive the head (2) and a part of the stem (3) of said lifting bolt (2,3) and to retain the latter in a position, in which the stem (3) forms an angle of approximately 90 degrees with the abutment surface (8) on the arm (7), said<inverted T-shaped slot (10) at its end opposite to the retaining position for the lifting bolt (2,3) having a cut-out (11), through which the head (2) of the lifting bolt 2,3) may be inserted in and removed from said inverted T-shaped slot (10) , characterized in a) that a slot (12) extends centrally and substantially diametrically in the body (6) and opens into the inverted T-shaped slot (10) , and b) that mutually aligned bores (13) for receiving a bolt (14) for attachment of various connecting means to the body (6) extend within the region of said slot (12) eccentrical in the body (6) and substantially diametric¬ ally opposite the retaining position for the lifting bolt (2,3). 2. Load-engaging device according to claim 1, char- acterized in that the connecting means is a chain (16) , the end link (17) of which is retained in the central slot (12) by the bolt (14) through the latter. 3. Load-engaging device according to claim 1, char¬ acterized by an universal joint (19) having a first lug (18) with a through bore retained by the bolt (14) through the central slot (12) , as well as a fork placed transversely of said first lug (18) with mutually aligned bores extending through the legs (20) of said fork for receiving a bolt (21), to which a second lug (22) is secured between the legs (20) of the fork, said second lug (22) having an eye (23) for engaging a connecting means, such as a shackle or a hook.

Inventors: JESSEN LAURIDS A, JESSEN, LAURIDS, A.
Applicants: JESSEN LAURIDS A, JESSEN, LAURIDS, A.
Application year: 1993
Main classification: B66C1
IPC codes: B66C1