Abstract:
An orientation apparatus for aiding the release of a lifting eye from a lifting anchor has a concave web with an open slot. The slot is configured to locate around a lifting anchor located within a hemispherical recess of a concrete element. The web is shaped to fit into the recess and so that a lifting eye, which engages the lifting anchor, can seat therein and be held so that its axis of rotation is prevented from rotating relative to the web. A shank which is integral with the web extends over a surface of the concrete element and away from the recess, and has a cable guide at a distal end trough which a cable, which is adapted for connection to the lifting eye and which can be pulled to rotate the lifting eye to a release position, is guided.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This is a National Phase Application of a Patent Cooperation Treaty application filed on Sep. 5, 2002 (International Application No. PCT/NZ02/00171) which claims priority to NZ514030 filed on Sep. 2001 and NZ515071 filed on Oct. 29, 2001. 
   FIELD OF INVENTION 
   This invention relates to methods and apparatus for orientating, guiding or restricting the movement of a rotatable means and has been devised particularly though not necessarily solely for use in the construction industry for lifting and handling concrete elements. 
   BACKGROUND OF THE INVENTION 
   The conventional use of lengths of cable or wire cast into a concrete element, such as a concrete wall or a slab, to form a lifting hook for lifting of the element is unsafe and the hooks are prone to damage. 
   Modern lifting systems utilise lifting anchors which are partially cast and embedded in a concrete element that is to be lifted. The lifting anchors have a forged head which is exposed to engage with a hooking device mown as a ‘lifting eye’. Recesses are commonly provided on the surface of the concrete element at locations where there is a lifting anchor such that the exposed portion including the forged head of the individual lifting anchors is recessed below the concrete surface being protected from damages. 
   A recess is commonly formed and shaped by a recess former which is provided to encapsulate the exposed portion of the lifting anchor during curing of the concrete element. Known recess formers are in the shape of either a hemisphere or a truncated hemisphere with two planar sides. It is practically convenient and cheap to cast a hemispherical recess using a hemispherical recess former rather than formers having planar sides. Recess formers are often subject to problems of orientation and difficulties arise when disengaging the lifting eye. This is due to the fact that the lifting eye swivels about the head of the anchor but can only be disengaged once it is orientated. After a concrete wall has been leveraged up, it is simply too dangerous and impractical for a workman to climb up a ladder and manually release the lifting eye. It is therefore desirable that the lifting eye can be disconnected remotely. 
   Previous attempts to solve this problem have involved the use of truncated hemispherical formers with planar sides. These improved treated formers are advantageous in that the flat sides of a recess that is shaped by these formers restrict the rotational movement of the lifting eye. As a result, the lifting eye can be remotely released by pulling a cable or a wire which is connected thereto, since the rotational movement of the lifting eye is unidirectionally restricted. However, truncated hemispherical formers are often expensive to manufacture, and vulnerable to inaccuracies when orientated within a concrete element. The truncated formers are also often subject to movement during curing, the result of which requires the positioning of a supporting means, for example a chair, which carries each former, so as to consolidate the position of the former. Furthermore, given the nature of the common construction workplace, the supporting means having a former therein are often susceptible to inadvertent shifting or movement, for example, by workmen. 
   OBJECT 
   It is therefore an object of the present invention to provide an orientation apparatus which will overcome the foregoing disadvantages in a simple yet effective manner or which will at least provide the public with a useful choice. 
   STATEMENT OF THE INVENTION 
   Accordingly in one aspect the present invention consists in orientation apparatus which includes at least one locating men, a guiding manes, and a control men guided by the gliding means and connectable in use to a separate rotatable means, the locating means being adapted to restrict the rotational movement in use of the rotatable means to rotational movement about a selected axis of rotation. 
   Accordingly in another aspect the present invention consists in a method of restricting the rotational movement of a rotatable means, the method including the steps of providing orientation apparatus which includes at least one locating means, providing a guiding means, and providing a control means guided by the guiding means and connectable in use to a separate rotatable means, the locating means being adapted to restrict the rotational movement in use of the rotatable means to rotational movement about a selected axis of rotation. 
   Accordingly in a further aspect the present invention consists in orientation apparatus including a remotely operable control means which is adapted to allow or effect remote disengagement of a rotatable means engageable in use with an anchoring means. 
   To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the description herein are purely illustrative add are not intended to be in any sense limiting. 

   
     DRAWING DESCRIPTIONS 
     One presently preferred embodiment of the invention will now be described with reference to the accompanying drawings, wherein, 
       FIG. 1  is a perspective view of an orientation apparatus in accordance with the present invention. 
       FIG. 2  is a perspective view showing a lifting system into which the orientation apparatus 
     of  FIG. 1  is adapted to fit. 
       FIG. 2   a  is a perspective view of a recess former which forms the recess of  FIG. 3 . 
       FIG. 3  is a perspective view of the orientation apparatus of  FIG. 1  sitting in the recess of a concrete wall 
       FIG. 3   a  is a cross sectional view showing the orientation apparatus of  FIG. 1  sitting in the recess of a concrete wall. 
       FIGS. 4 ,  4   a ,  5  and  6  arc side elevations showing the lifting system with the orientation apparatus of  FIG. 1  in different orientations. 
       FIG. 6   a  is a cross sectional side elevation of the orientation apparatus of  FIG. 1  incorporated into the lifting system of  FIG. 2 . 
       FIG. 7  is a front view illustrating how the orientation apparatus of  FIG. 1  is fitted into the lifting system of  FIG. 2 . 
       FIG. 8  is a perspective view illustrating how the orientation apparatus of  FIG. 1  is fitted into the lifting system of  FIG. 2 . 
       FIG. 9  is a plan view of the orientation apparatus of  FIG. 1  when in use. 
       FIG. 10   a  is a plan view of the most preferred embodiment of the orientation apparatus of  FIG. 1 . 
       FIG. 10   b  is a side elevation of the lost preferred embodiment of the orientation apparatus of  FIG. 1 . 
       FIG. 10   c  is an end view of the most preferred embodiment of the orientation apparatus of  FIG. 1 . 
       FIG. 11  is a perspective view showing the preferred embodiment of the yoke of the lifting system of  FIG. 2 . 
       FIG. 12  is a schematic drawing illustrating a specific disposition of the orientation apparatus of  FIG. 11   a  and the yoke of  FIG. 12 . 
   

   DETAILED DESCRIPTION 
   Referring to  FIG. 1 , a perspective view of orientation apparatus generally referenced  1  is shown. The apparatus  1  is formed to provide locating means which can be in the shape of a bifurcated fork (ie. for example blunt prongs or tines  2  and  4 ), a web  3  with side portions  82  and  84  and a middle portion  86 . An elongate member (eg. a shank)  6  which extends from the fork is connected to an end piece  8 . The end piece  8  carries guiding means such as an aperture  42  in the end piece  8 . The web  3  defines a cavity  20  having an open slot  7 . The cavity  20  of the apparatus is adapted to fit into a hemispherical recess  10 , which is shown in  FIG. 2 , of an element such as a concrete slab or wall  11  to be lifted.  FIG. 2  illustrates a lifting system that is commonly used in the constriction industry, including an anchor  14  which is partly embedded in the recess  10  of a concrete wall or slab  11 , a rotatable means (referred to as a yoke or sheave)  24  which is the main part of an engaging means commonly referred to as a lifting eye), a lifting shackle  26  and a metallic chain  30 . It can be observed in  FIG. 2  that the head  12  of an anchor  14  projects into the recess  10 , which is cast by a hemispherical recess former (refer to  FIG. 2   a  ), in a concrete slab  11 . 
     FIG. 2   a  shows a hemispherical recess former  50  which includes a cup and a lid  51  when in use encapsulating the top portion of the anchor  14  (including the head  12 ). Preferably a footing  52  with feet  54  having locating toes which preferably comprise spikes  56  is mounted on the base of anchor  14  so as to fix and locate the position of the anchor  14  and the recess  10  while the moist concrete slab  11  is setting. The recess former  50  can be broken open by a screw driver or the like after the concrete slab  11  has solidified. 
   Also, referring to  FIG. 3 , in operation, the prongs or lines  2  and  4  of the orientation apparatus  1  shown in  FIG. 1  are fitted into the recess  10  of the concrete slab  11 . The construction and arrangement of the orientation apparatus  1  and the recess  10  are more clearly shown in  FIG. 3   a . The tines  2  &amp;  4  which have planar inner side surfaces  16  &amp;  18 , define the cavity  20  with a curved base  58 . The yoke  24  is then provided to engage with the protruding head  12  in the slab  11 . 
   Referring back to  FIG. 2 , the lifting eye which comprises a coupling piece or yoke  24  and a lifting shackle  26  is shown. The yoke  24  is in the shape of a sheave with substantially planar sides  40  and is provided to couple with the head  12  of the anchor  14 . The yoke  24  has two truncated faces  28  and a hole (not clearly visible in  FIG. 2 ) through which the lifting shackle  26  passes. The lifting shackle  26  is in turn connected to a chain  30  (eg. metallic chain) of a crane rig for hoisting the concrete slab  11 . The bottom portion of the yoke  24  provides a downwardly open slot  32  of dimensions corresponding to those of the head  12  and the shank  62  of the anchor  14 . The cross section of slot  32  provides a substantially T-section cylindrical groove that is open to the outside via an opening  34 . 
   The following describes the operation of the lifting system. 
   Referring to  FIGS. 2 and 4 , the yoke  24  of the lifting system is connected to the anchor head  12  in the slab  11  by admitting the anchor head  12  into the slot  32  of the yoke  24  via the opening  34 . The yoke  24  preferably has a spur  36  which is then flipped or rotated in the direction of arrow  80  (refer to  FIG. 4 ) until it rests on the outer surface  40  of the concrete element  11 . This step is essential to the displacement of the opening  34  to allow the anchor head  12  to be received into the slot  32 . It is important to note that later for the yoke  24  to be successfully disengaged remotely (after the concrete element  11  is erected or transported) with the assistance of the orientation apparatus  1 , the yoke  24  should be orientated and disposed such that spur  36  (prior to being rotated) is on the same side as the shank  6  as shown in  FIG. 4 , instead of in a position that is 180° away from the shank  6  as shown in  FIG. 4   a.    
   Referring now to  FIG. 5 , once the yoke  24  is engaged with the anchor head  12 , a load can be applied from any direction in order to lift or tilt the concrete element  11 .  FIGS. 6 and 6   a  demonstrate how the concrete wall  11  can be lifted from any direction. It can be seen that the lifting shackle  26  can deflect depending on the direction from which the force or load is exerted. In other words, the yoke (ie. the lifting eye)  24  has been designed in such a way that it cannot accidentally disengage while under load. The design and mechanism of the lifting eye will not be discussed in detail as they are outside the scope of the current invention being known apparatus. 
   Turning to  FIG. 6   a , a cross sectional side view of the orientation apparatus  1  in use is shown. The concrete element  11  is shown in a substantially upright disposition. Once the load is taken off the shackle  26 , an operator, from a remote location, can pull a control means (such as a remote-controllable cable or wire or the like)  38  which is connected to the spur  36 , passing through and guided by the guiding means (ie. an aperture)  42  (as shown in  FIG. 1 ) provided in the end piece  8 . As a consequence, the yoke  24  (ie. the lifting eye) will rotate in the direction of arrow  66 , thereby enabling the yoke  24  to be remotely released from the head  12  of the anchor  14  via the opening  34 . 
   It should be understood that when restricted by the prongs or tines  2  and  4  of the orientation apparatus  1 , the motion of the yoke  24  can only be on the plane defined by the lines A-A and B-B, as shown in  FIG. 6 . It is important to note that the opening  34  is provided along the line of symmetry  68  (refer back to  FIG. 2 ) of the yoke  24 . The yoke  24  therefore has to be properly orientated as described above such that it is restricted from any rotational movement about the anchor  14  or else it cannot disengage from the anchor head  12 . Referring to  FIGS. 6   a  and  7 , the orientation apparatus  1  being fitted into the recess  10 , defines the cavity  20  which has planar sides  16  and  18  that abut the outer surfaces  40  of the yoke  24  once the yoke  24  is engaged with the anchor head  12 . As soon as the lifting eye disengages with the anchor head  12 , the orientation apparatus  1  will fall out of the recess  10  automatically wider gravitational force being guided by the cable or wire  38  enables retrieval and collection of the apparatus  1  by the operator on the ground. 
     FIG. 7  is a front view showing how the orientation apparatus  1  fits into the lifting system. The planar internal surfaces  18  &amp;  16  of the prongs or tines  4  &amp;  2  abut the lateral surfaces  40  of the yoke  24  respectively so as to restrict the yoke  24  to rotational movements only about a selected axis of rotation. The selected axis of rotation is preferably substantially perpendicular to the anchor  14 . The front surface  88  of the yoke  24  abuts the middle and side portions  86 ,  82  and  84  of the web  3  such that the orientation apparatus  1  is locked in place without being able to fall out of the recess  10 . The yoke  24  is essentially free to rotate about the anchor  14  with the orientation apparatus  1 , but will be restricted to only about an axis that is perpendicular to the planar surfaces  16  &amp;  18  when the orientation apparatus  1  is locked in a specific position 
   Turning to  FIG. 8 , a perspective view of the orientation apparatus  1  being incorporated into the lifting system is shown. After the concrete element  11  has been leveraged up to a substantially upright position or transported to any desired disposition or location, it can be appreciated that once the load is Hen off the shackle  26 , the yoke  24  (ie. the lifting eye) may swivel together with the orientation apparatus  1  about the anchor means  14  in either directions indicated by arrows  70  in the plan view of  FIG. 9 . With the control means (ie. the cable, wire or tendon)  38 , the operator can pull the yoke  24  and the orientation apparatus  1  to the can be upright position, as shown in  FIG. 10 , as well as aligning them at the same time. The control means  38 , being connected to the yoke  24  and pulled, is coincident with the length of the elongate member (eg. the shank)  6  of the apparatus  1 . Regardless of the orientation of the yoke  24  and of the orientation apparatus  1 , which are random as soon as the load is taken off the shackle  26 , the operator can “regulate” the orientation of the yoke  24  as well as the orientation apparatus  1 , and cause the yoke  24  to rotate in the direction as shown by arrow  66  (as shown in  FIG. 6   a  ) at the same time by pulling the cable or wire  38  from the ground until the anchor head  12  disengages from the lifting eye via the opening  34 . 
   Variations 
   The plan view, side elevation and front view of the most preferred embodiment of the orientation apparatus  1  are shown respectively in  FIGS. 10   a, b  and  c . It will be appreciated that the length and shape of the shank  6  may vary. All elongate shank is preferred to make it easier for the operator to monitor the rotational movement, and judge the orientation, of the orientation apparatus  1  from the ground. Also, the spur  36  may optionally be substituted by an elongate member  74  as shown in  FIG. 11 . This embodiment is beneficial in that the lifting eye will automatically rotate to a position that allows disengagement with the anchor head  12  (not shown) via the opening  34 , due to the fact that the elongate member  74  (which is preferred to be made of a heavy metal) will drop due to its own weight once the load is taken off the shackle  26  and the orientation of the orientation apparatus  1  is “regulated” to the substantially upright position (as shown in  FIG. 9 ). The lifting eye may not disengage wit the anchor head  12  unless or until a pulling force is exerted by the operator. The elongate member  74  is also advantageous in that it gives the lifting eye more leverage. It should however be noted that the elongate member  74  may counterweight the shank  6  of the orientation apparatus  1 . As a result, the orientation apparatus  1  and the elongate member  74  may end up in a disposition as shown in  FIG. 11  rather than the orientation apparatus falling on the weight of its shank  72  to automatically end up in the substantially vertical position as shown in  FIG. 9  after the load is taken off the shackle  26 . This however may be overcome or regulated by the pulling force exerted by the operator. 
   Advantages 
   It can thus be seen that at least in the preferred form of the invention an orientation apparatus is provided which offers the following advantages:
         1. impeding multidirectional movement of the rotatable yoke of the lifting system;   2. allowing successful remote release of the rotatable yoke and/or the orientation device;   3. easy and economical to manufacture;   4. allowing use of non-directional hemispherical recesses to be used with simplified chairs which are also easy and economical to manufacture;   5. easy to implement and operate, without the need of altering the construction of the existing lifting system.