NZ790116A - Clutch having limited articulation - Google Patents

Abstract

clutch for lifting a concrete component, including a toroidal connector, a latch in the form of a locking ring movable relative to the toroidal connector between a disengaged condition and an engaged condition, the locking ring having a handle extending radially outwardly from the toroidal connector, and a coupler for coupling the toroidal connector to a lifting apparatus, wherein the coupler includes a first part and a second part pivotal relative to the first part, the coupler being arranged to limit pivotal movement of the second part relative to the first part. or, and a coupler for coupling the toroidal connector to a lifting apparatus, wherein the coupler includes a first part and a second part pivotal relative to the first part, the coupler being arranged to limit pivotal movement of the second part relative to the first part.

Description

A clutch for lifting a concrete component, ing a toroidal connector, a latch in the form of a locking ring movable relative to the toroidal connector between a disengaged condition and an engaged condition, the locking ring having a handle extending radially outwardly from the toroidal connector, and a coupler for coupling the toroidal tor to a lifting apparatus, wherein the coupler includes a first part and a second part pivotal relative to the first part, the coupler being arranged to limit pivotal nt of the second part relative to the first part.

NZ 790116 CLUTCH HAVING LIMITED ARTICULATION FIELD OF THE ION This invention relates to a clutch. More particularly, but not exclusively, the invention relates to an articulated clutch for lifting a concrete component by way of an anchor cast into the concrete component.

BACKGROUND OF THE INVENTION It is known to provide a clutch for lifting concrete ents where the clutch is used to lift, for example, concrete panels after casting by way of a cast-in edge-lift anchor and for moving them to curing racks and later onto trucks for transportation to a construction site. However, the applicant has identified that there are antages with existing lifting clutches.

The applicant has determined that it would be beneficial for there to be provided a clutch which overcomes or at least ates one or more disadvantages of existing clutches.

Accordingly, examples of the present invention seek to avoid or at least ameliorate the disadvantages of existing clutches.

SUMMARY OF THE INVENTION In ance with one aspect of the present invention, there is provided a clutch for lifting a concrete component, including a toroidal connector, a latch in the form of a g ring movable relative to the toroidal connector between a aged condition and an engaged condition, the locking ring having a handle extending radially outwardly from the toroidal connector, and a coupler for coupling the toroidal tor to a lifting apparatus, wherein the coupler includes a first part and a second part pivotal relative to the first part, the coupler being arranged to limit pivotal movement of the second part relative to the first part.

Preferably, the coupler is ed to limit pivotal movement of the second part ve to the first part in one direction. More preferably, the coupler is arranged to limit pivotal movement of the second part relative to the first part such that said limit prevents a tip of the locking ring handle passing through an inner loop of the second part.

In a preferred form, the first part includes a shoulder arranged to bear t the second part at said limit.

The second part may include a shoulder arranged to bear against the first part at said limit. ably, the coupler is arranged to limit pivotal movement of the second part relative to the first part such that said limit ts the second part from engaging with the locking ring handle to rotate the locking ring handle. More preferably, the coupler is arranged to limit pivotal movement of the second part relative to the first part such that said limit prevents the second part from engaging with the locking ring handle to rotate the locking ring handle from the engaged condition to the disengaged condition.

There is also disclosed a clutch for lifting a concrete component, including a toroidal connector, a latch movable relative to the toroidal connector between a disengaged condition and an engaged condition, and a coupler for coupling the toroidal connector to a g apparatus, wherein the coupler includes a first part and a second part pivotal ve to the first part about a pin, and wherein the r includes a tamper evident indicator to indicate that the clutch has not been disassembled.

Preferably, the tamper evident indicator is arranged to indicate that the pin has not been removed from the coupler.

In a preferred form, the coupler is provided with a bush around a central portion of the pin. More preferably, the pin has a ar groove about its circumference and the tamper evident indicator includes a member in engagement with the circular groove to prevent nt of the pin along its longitudinal axis relative to the bush.

More ably, the member is anchored to the bush.

In one form, the member is in the form of a rivet.

Alternatively, the member is in the form of a roll pin.

There is also sed a clutch for lifting a concrete ent, including a toroidal connector, a latch movable relative to the toroidal connector between a disengaged condition and an d condition, and a coupler for coupling the toroidal connector to a lifting apparatus, wherein the toroidal connector has a circular seat for sitting upon a circular upper surface of a head of and anchor coupled to the toroidal connector, n the circular seat terminates in a radial bearing surface for abutment with a castellation of the .

Preferably, the circular seat has a first radial bearing surface for abutment with a first castellation of the anchor and a second, opposite, radial bearing surface for abutment with a second castellation of the anchor.

In a preferred form, the circular seat is circular about an arc having a centre at a central longitudinal axis of the latch. More preferably, the radial g surface is radial relative to a circle having a centre at the central longitudinal axis of the latch.

There is also disclosed a clutch for lifting a concrete component, including a toroidal connector, a latch movable relative to the toroidal connector between a disengaged condition and an engaged condition, and a coupler for coupling the toroidal connector to a lifting apparatus, wherein the coupler is articulated.

Preferably, the coupler includes a first part and a second part pivotal relative to the first part, the first part forming a first loop engaged through the toroidal tor and the second part forming a second loop for receiving the lifting apparatus.

Preferably, the first loop is a different size to the second loop. More preferably, the first loop is smaller than the second loop.

In a preferred form, the second loop is adapted to allow direct fitment of a lifting chain while also ng direct fitment of a lifting hook.

It is red that the coupler es an elongated pin about a longitudinal axis of which the second part is pivotal ve to the first part.

Preferably, the latch is in the form of a ar latch passing through an inner circular passage of the toroidal connector.

There is also disclosed a clutch for lifting a te component, including a toroidal connector, a latch movable relative to the toroidal connector between a disengaged condition and an engaged condition, and a coupler for coupling the toroidal connector to a lifting apparatus, wherein the r es a first part and a second part pivotal relative to the first part about a pin, the first part having a first circular arc and the second part having a second circular arc, and wherein the pin is located such that a longitudinal axis of the pin is dicular to a line connecting a centre of the first arc to a centre of the second arc.

In accordance with another aspect of the present invention, there is provided a clutch for lifting a concrete component, including a toroidal connector, a latch in the form of a g ring e relative to the toroidal connector between a disengaged condition and an engaged condition, the locking ring having a handle extending radially outwardly from the toroidal connector, and a coupler for ng the toroidal connector to a lifting apparatus, wherein the locking ring handle is arranged to abut the coupler to limit rotational movement of the coupler relative to the al connector.

Preferably, the locking ring handle is arranged to limit rotational movement of the r relative to the toroidal tor such that said limit ts a tip of the g ring handle passing through an inner loop of the coupler.

Preferably, the coupler is arranged to limit pivotal movement of the second part relative to the first part in two directions.

Preferably, the first part is connected to the second part by a pivotal coupling. More preferably, the pivotal coupling includes a first hinge at one side of the coupler and a second hinge at an opposite side of the coupler. Even more preferably, the first hinge and the second hinge are arranged to provide pivotal movement along a common axis.

In a preferred form, the r includes a bush between the first hinge and the second hinge. More preferably, the bush includes a stop for abutting against the first part or the second part to limit rotation of the second part relative to the first part. Even more preferably, the bush is arranged to rotate with the second part and the stop is adapted to abut against the first part to limit rotation of the second part relative to the first part.

Preferably, the first part is provided with a tab for abutment with the stop. More preferably, the stop is in the form of a cutout having two stop surfaces, comprising a first stop surface for abutting one side of the tab and a second stop surface for abutting an opposite side of the tab for limiting on of the second part relative to the first part in two directions.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is further bed by way of miting e only with reference to the accompanying drawings, in which: Figure 1 shows a perspective view of an articulated clutch for lifting a concrete component in accordance with an example of the present ion; Figure 2 shows a side view of the articulated clutch; Figure 3 shows a front view of the articulated clutch; Figure 4 shows an exploded view of the articulated clutch; Figure 5 shows a front view of the articulated clutch, depicting a tamper evident device incorporated into the clutch; Figure 6 shows a side cross-sectional view of the articulated clutch, depicting location of the tamper evident device when in situ; Figure 7 is a detailed perspective view of an end of the tamper evident device when in situ; Figure 8 shows a ctive view of the articulated clutch, depicting a limit of rotation of a second part of a coupler relative to a first part of the coupler; Figure 9a shows a front view of the articulated clutch, depicting the limit of rotation of the second part relative to the first part; Figure 9b shows a cross-sectional view of the articulated clutch taken along line A-A shown in Figure 9a; Figure 9c shows a side view of the articulated clutch, depicting the limit of rotation of the second part relative to the first part; Figure 10 shows a side perspective view of a toroidal connector of the articulated ; Figure 11a shows a front view of the toroidal connector; Figure 11b shows a side cross-sectional view of the toroidal connector taken along line A-A shown in Figure 11a; Figure 12 shows an opposite side perspective view of the toroidal connector; Figure 13 shows a cross-sectional view of the toroidal connector when ted to a head of a cast-in anchor, taken through a central plane of the toroidal connector; Figure 14 shows a front view of a coupler of the articulated clutch, depicting an axis of rotation of the second part relative to the first part with respect to a central line of the coupler connecting a centre of a circular arc of the first part with a centre of a circular arc of the second part; Figure 15 shows a side view of an articulated clutch in accordance with another example, depicting the limit of rotation of the r relative to the toroidal connector; Figure 16 shows a perspective view an articulated clutch in accordance with another example, depicting a g ring handle being sufficiently long to limit rotation of the coupler relative to the toroidal connector; Figure 17 shows a top view of the articulated clutch shown in Figure 16; Figure 18 shows a side view of the lated clutch shown in Figure 16; Figure 19 shows a perspective view of the articulated clutch in accordance with another example; Figure 20 shows a detailed view of portion labelled "B" in Figure 19; Figure 21 shows a front view of the articulated clutch shown in Figure 19 and Figure 20; and Figure 22 shows a detailed view of n A-A shown in Figure 21.

DETAILED DESCRIPTION As can be seen in Figures 1 to 18 of the drawings, the present ion may provide an articulated clutch for lifting a te component. Advantageously, the articulated clutch has a r including a first part and a second part pivotal relative to the first part. The first part forms a first loop and the second part forms a second loop. The two loops are dissimilar in size such that the top loop (when lifting) provided by the second loop will accept a crane or lifting hook but can still accept a suitable size chain fitted directly to the top loop.

More specifically, as shown in Figures 1 to 4, there is provided a clutch 10 for lifting a concrete component (not shown). The concrete component may take several forms including, but not limited to, a concrete panel. The concrete ent may have a cast in edge lift anchor (for example), the anchor having an eye which is used for connection to a al connector of the clutch 10 for lifting the concrete panel.

The clutch 10 includes a toroidal connector 12 and a latch 14. The latch 14 is movable relative to the toroidal connector 12 between a disengaged condition (in which the latch 14 is retracted into a toroidal sleeve of the al connector 12) and an engaged condition (see Figure 2) in which the latch 14 spans a gap of the al connector 12 for engagement with an eye of and anchor cast into a concrete component. The clutch 10 also includes a coupler 16 for coupling the toroidal connector 12 to a lifting apparatus 18, n the coupler 16 is articulated.

The coupler 16 includes a first part 20 and a second part 22 pivotal relative to the first part, the first part forming a first loop 24 engaged through the toroidal connector 12 and the second part 22 forming a second loop 26 for receiving the lifting apparatus 18.

As shown, the first loop 24 is a different size to the second loop 26. More specifically, the first loop 24 is smaller than the second loop 26. The second loop 26 is adapted to allow direct fitment of a lifting chain while also allowing direct fitment of a lifting hook.

Accordingly, the r 16 allows the direct t of a suitable size chain like a hammerlock but also allows for direct fitment to a lifting hook as shown in Figure 5.

The articulation of this format of clutch handle (in the form of coupler 16) addresses the issue of welded handles getting bent around the head of a concrete panel as the panel is lifted off a truck at a building site, as the concrete panel is lifted and then rotated 90° before being positioned. It does this while also meeting the needs of the precast factory where the clutch 10 is used to lift concrete panels from horizontal to vertical after casting and for moving them to curing racks and later onto trucks for transportation to a building site.

The compact size of the two loops (the first loop 24 and the second loop 26) also allows for greater head height within the factory, allowing for a gain in lifting height. This in turn allows for increased panel sizes as well as increased manoeuvrability within the factory, where lifting height is d by the gantry height.

As shown in Figure 4, the coupler 16 includes an ted axle pin 28 about a longitudinal axis of which the second part 22 is pivotal relative to the first part 20. The first part 20 includes a forked end and a rked end. The forked end of the first part engages with a non-forked end of the second part 22, s the non-forked end of the first part 20 engages with a forked end of the second part 22. The ends of the first part 20 and the second part 22 are provided with apertures through which the axle pin 28 is passed so as to hold together in pivotal relationship the first part 20 and the second part 22.

With reference to Figure 4, the latch 14 is in the form of a circular latch g through an inner circular passage of the toroidal connector 12. The latch 14 has a handle 30 for moving the latch 14 between the disengaged condition and the engaged condition, the handle 30 extending generally radially outwardly relative to a centre of the al connector 12.

As shown most clearly in Figure 14, the first part 20 has a first circular arc 32 and the second part 22 has a second circular arc 34. The pin 28 is located such that a longitudinal axis of the pin 28 is perpendicular to a line 36 connecting a centre 38 of the first arc 32 to a centre 40 of the second arc 34.

Accordingly, the axle pin 28 runs perpendicular to the centre line between the arcs of the two loops 24, 26. This allows the handle (coupler 16) to be symmetrical such that when rotated about the toroidal connector 12, the r 16 has the same angular movement either way. This perpendicular configuration may also assist in the articulation of the coupler 16 when it needs to be bent around the end of a concrete panel being lifted.

Turning to Figures 8 to 9c, the latch 14 in the form of the locking ring may have a handle extending generally radially outwardly from the toroidal connector 12. The r 16 may be specifically arranged to limit pivotal movement of the second part 22 relative to the first part 20. In other words, in Figure 2 the first part 20 and the second part 22 are shown in a co-planar configuration, whereas in Figures 8 to 9c there is shown a limit of pivotal movement of the second part 22 relative to the first part 20.

In one form, the coupler 16 may be arranged to limit pivotal movement of the second part 22 relative to the first part 20 in one direction. The r 16 may also be arranged to limit pivotal movement of the second part 22 relative to the first part 20 such that the limit prevents a tip 42 of the locking ring handle passing through an inner loop 26 of the second part 22.

As best shown in the cross-sectional drawing shown in Figure 9B, the first part may include a shoulder 44 arranged to bear against the second part 22 at the limit.

Alternatively, or in addition, the second part 22 may include a shoulder ed to bear t the first part 20 at the limit.

In a red example, the coupler 16 is arranged to limit pivotal nt of the second part 22 relative to the first part 20 such that the limit prevents the second part 22 from engaging with the g ring handle 30 to rotate the locking ring handle 30.

More specifically, the r 16 may be arranged to limit pivotal movement of the second part 22 relative to the first part 20 such that the limit prevents the second part 22 from engaging with the locking ring handle 30 to rotate the locking ring handle 30 from the engaged condition to the disengaged condition.

In this way, the two loops 24, 26 are limited in rotation in one direction to eliminate the large loop being able to hook under the locking ring handle 30. The applicant has identified that, where the upper loop (secondly 26) is large enough to accept a lifting hook, then that loop has the potential to cook under the g ring handle 30 and could allow the clutch 10 to become disconnected from the anchor unintentionally.

Advantageously, by limiting rotation in this way examples of the t invention are able to prevent unintentional disconnection.

As shown in Figures 4 to 7, the second part 22 is pivotal relative to the first part 20 about the axle pin 28. The coupler 16 may also include a tamper t indicator 46 to indicate that the clutch 10 has not been disassembled. The tamper evident indicator may be is arranged to indicate that the axle pin 28 has not been removed from the coupler 16. In the example shown, the coupler 16 is ed with a bush 48 around a central portion of the axle pin 28, the central portion being n the distal end of the first part 20 and the second part 22. The second part 22 may be provided with longitudinal slots which are received in corresponding longitudinal grooves of the bush 48 to keep the bush 48 aligned ve to the second part 22 and to prevent rotation of the bush 48 relative to the second part 22.

With reference to Figure 4, the pin 28 may have a circular groove 50 about its circumference and the tamper evident indicator 46 may include a member in engagement with the circular groove 50 to prevent movement of the pin 28 along its longitudinal axis relative to the bush 48. In addition, the toroidal connector 12 may be provided with a stop pin 52 to limit rotation of the latch 14 relative to the al connector 12. The member 46 may be anchored to the bush 48. With reference to Figure 6, the member 46 may be in the form of a rivet which passes through the bush 48 and has a flange at each end to retain the rivet relative to the bush 48. Alternatively, the member may be in the form of a roll pin.

In this way, there is provided a tamper t centre bush 48. The bush 48 may be profiled to match the loops 24, 26, the bush 48 being secured by either a rivet or a roll pin that does not pass through the middle of the axle pin 28 but passes tangentially through the groove 50 on the axle pin 28. If secured by a rivet, the rivet will be ed to secure it and the deformed end may have a branded logo (see Figure 5 and Figure 7) to indicate the handle (coupler 16) has not been tampered with. If a roll pin is used, then a seal (possibly in the form of epoxy or solder) may be used to indicate the clutch has not been disassembled.

As will be appreciated from the drawings, the bush 48 has a non-cylindrical shape. The locking pin or rivet 46 runs tangentially through the groove 50 in the axle pin 28.

Accordingly, this provides an indication to the user that the clutch 10 has not been tampered with since proof testing. The applicant has identified that a commercial hammerlock can be disassembled and reassembled without it being evident that this has ed. Therefore, the original proof testing and certification could be invalid as this must be conducted anytime the clutch is modified.

Advantageously, the incorporation of a tamper evident feature gives the user confidence that the clutch 10 has not been tampered with since proof testing. The unique shape of the bush 48 allows the rivet or cross pin 46 to hold the axle 28 by the groove 50 rather than passing the centre of the axle 28. This creates far less stress concentration, making the axle 28 stronger. The unique shape of the bush 48 also allows the use of the tamper evident rivet 46. The tially positioned groove 50 allows for easier assembly of the system compared to that of a centrally located hole as less alignment is ed (that is, alignment is only required in the x-axis and not in both x and y axes).

Turning now to Figures 10 to 13, the toroidal connector 12 may be ed with a circular seat 54 for sitting upon a circular upper e 56 of a head 58 of an anchor 60 coupled to the toroidal connector 12. The circular seat 54 terminates in a radial bearing surface 62 for face-to-face abutment with a castellation 64 of the anchor 60.

As can be seen most clearly in Figure 13, the circular seat 54 has a first radial bearing surface 62 for nt with a first castellation 64 of the anchor and a second, opposite, radial bearing surface 62 for nt with a second lation 64 of the anchor 60.

In the example shown, the circular seat 54 is ar about an arc 66 having a centre at a central longitudinal (tangential) axis 68 of the latch 14. More specifically, the radial bearing surface 62 is radial relative to a circle having a centre at the central longitudinal axis 68 of the latch 14.

Advantageously, the provision of the radial bearing surfaces 62 improve the interface of the toroidal tor 12 and the anchor 60, when compared with existing connectors which abut at an edge or point. The applicant has identified that the o-face g provides less pressure owing to the greater surface area of contact, reducing wear on the toroidal connector 12. In particular, the applicant has identified that previous clutch designs for castellated anchors would see the sides of the torus bear on the castellations (or in a point or line contact where the sides of the torus meet the curved cut out). In the example of the ion shown, a new angled face interacts with the angled face of the anchor 60 to achieve a far greater bearing area resulting in less wear on the torus over time. This is achieved by way of the angled faces on the al connector 12 which bear against the castellations 64 on the head 58 of the anchor 60. This is in contrast to existing arrangements where a toroidal connector bears on flat faces of the anchor or, where the anchor is castellated, the sides of the torus bear on the castellations.

With reference to Figures 15 to 18, there is shown an alternative example of the present invention in which the locking ring handle 30 is arranged to abut the coupler 16 to limit rotational movement of the coupler 16 relative to the toroidal connector 12. In particular, the locking ring handle 30 is arranged to limit rotational movement of the coupler 16 relative to the toroidal connector 12 such that the limit prevents a tip 42 of the locking ring handle 30 g through an inner loop 26 of the coupler 16. This may be achieved by dimensioning the locking ring handle 30 such that the tip 42 of the locking ring handle 30 extends radially further from a centre of the toroidal connector 12 than an outermost edge of the coupler 16.

Turning to Figures 19 to 22, there is shown an example of the present invention in which the r 16 is arranged to limit pivotal movement of the second part 22 relative to the first part 20 in two directions. More specifically, as can be seen in Figure 19, the first part 20 is connected to the second part 22 by a pivotal coupling 70. In the example shown, the pivotal coupling 70 includes a first hinge 72 at one side of the coupler 16 and a second hinge 74 at an opposite side of the r 16. As can be seen, the first hinge 72 and the second hinge 74 are arranged to provide pivotal movement of the second part 22 relative to the first part 21 along a common axis which may be ensured by a single axle pin 28.

In the example shown in s 19 to 22, the pivotal ng 70 es a bush 48 between the first hinge 72 and the second hinge 74. The bush 48 includes a stop 76 for ng against the first part 20 or the second part 22 to limit rotation of the second part 22 relative to the first part 20. The bush 48 may be arranged to rotate with the second part 22 (for example, engaged with the second part 22 by way of a tongue and groove connection) and the stop 76 may be adapted to abut against the first part 20 to limit rotation of the second part 22 relative to the first part 20.

Figure 20 shows an ed and detailed view of the n labelled "B" in Figure 19.

In Figure 20 it can be seen that the first part 20 is provided with a tab 78 for nt with the stop 76.

Figure 21 shows a front view of the coupler 16, and Figure 22 shows an enlarged and detailed view of the cross-section ed A-A in Figure 21. With reference to Figure 22, the stop 76 may be in the form of a cutout 80 having two stop surfaces, sing a first stop surface 82 for abutting one side of the tab 78 and a second stop surface 84 for abutting an te side of the tab for limiting rotation of the second part 22 relative to the first part 20 in two directions.

Advantageously, this arrangement enables the limiting of angular movement of the second part 22 relative to the first part 20 in two directions and avoids a weakness which may otherwise be incurred if the limiting mechanism is attempted to be achieved within the first hinge 72 and/or the second hinge 74. The arrangement shown in Figures 19 to 22 takes advantage of there being no load or only little load on the coupler 16 when the rotation limiting mechanism is required to m its duty. In other words, the arrangement shown in Figures 19 to 22 changes how rotation of the upper loop relative to the lower loop is achieved. In this revised version, this limitation of rotation is achieved between radial shoulders in the centre bush 48 that limit the nt of a lug or tab on the inside of the lower loop.

The revised arrangement limits rotation in both directions, not just one direction. It will be understood by those skilled in the art that the two directions may be different (for example, in magnitude of limitation), thereby preventing the large loop – the second part – from interacting with the locking ring handle while allowing extra rotation in the opposite direction. This revised arrangement works n the lower loop – the first part 20 – and the centre bush 48, where the centre bush 48 is keyed to the upper bush to maintain alignment with the upper loop.

While various embodiments of the present invention have been described above, it should be tood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the ion. Thus, the present invention should not be limited by any of the above described exemplary embodiments.

The reference in this specification to any prior ation (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general dge in the field of endeavour to which this specification relates.

List of features: Clutch 12 Toroidal connector 14 Latch 16 Coupler 18 Lifting tus First part 22 Second part 24 First loop 26 Second loop 28 Axle pin Handle of the latch 32 First circular arc 34 Second circular arc 36 Line 38 Centre of the first arc 40 Centre of the second arc 42 Tip of the locking ring handle 44 Shoulder 46 Tamper evident indicator 48 Bush 50 Circular groove 52 Stop pin 54 Circular seat 56 Circular upper surface 58 Head 60 Anchor 62 Radial bearing e 64 Castellation 66 Arc 68 Central longitudinal axis of the latch 70 Pivotal coupling 72 First hinge 74 Second hinge 76 Stop 78 Tab 80 Cutout 82 First stop surface 40 84 Second stop surface

Claims (18)

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A clutch for lifting a concrete component, including a toroidal connector, a latch in the form of a locking ring movable relative to the toroidal connector between a disengaged condition and an engaged condition, the locking ring having a handle extending radially outwardly from the toroidal connector, and a coupler for coupling the toroidal connector to a lifting apparatus, wherein the coupler includes a first part and a second part pivotal relative to the first part, the coupler being arranged to limit pivotal movement of the second part relative to the first part.

2. A clutch as claimed in claim 1, n the r is arranged to limit pivotal movement of the second part relative to the first part in at least one direction.

3. A clutch as claimed in claim 2, wherein the coupler is arranged to limit pivotal movement of the second part relative to the first part in two directions.

4. A clutch as d in claim 2 or claim 3, n the coupler is arranged to limit pivotal movement of the second part relative to the first part such that said limit prevents a tip of the g ring handle passing h an inner loop of the second part.

5. A clutch as claimed in any one of claims 1 to 4, wherein the first part includes a shoulder arranged to bear against the second part at said limit.

6. A clutch as claimed in any one of claims 1 to 4, wherein the second part includes a shoulder arranged to bear against the first part at said limit.

7. A clutch as claimed in any one of claims 1 to 6, wherein the coupler is arranged to limit pivotal movement of the second part relative to the first part such that said limit prevents the second part from engaging with the locking ring handle to rotate the locking ring handle.

8. A clutch as claimed in claim 7, wherein the coupler is arranged to limit pivotal movement of the second part ve to the first part such that said limit prevents the second part from engaging with the locking ring handle to rotate the locking ring handle from the engaged condition to the disengaged condition.

9. A clutch as claimed in any one of claims 1 to 8, wherein the first part is connected to the second part by a pivotal coupling.

10. A clutch as claimed in claim 9, wherein the pivotal coupling includes a first hinge at one side of the coupler and a second hinge at an opposite side of the r.

11. A clutch as claimed in claim 10, wherein the first hinge and the second hinge are ed to provide pivotal movement along a common axis.

12. A clutch as claimed in claim 10 or claim 11, wherein the coupler includes a bush between the first hinge and the second hinge.

13. A clutch as claimed in claim 12, wherein the bush includes a stop for abutting against the first part or the second part to limit rotation of the second part relative to the first part.

14. A clutch as claimed in claim 13, n the bush is arranged to rotate with the second part and the stop is adapted to abut against the first part to limit rotation of the second part relative to the first part.

15. A clutch as claimed in claim 14, n the first part is provided with a tab for abutment with the stop.

16. A clutch as claimed in claim 15, wherein the stop is in the form of a cutout having two stop es, comprising a first stop surface for abutting one side of the tab and a second stop surface for abutting an opposite side of the tab for limiting rotation of the second part relative to the first part in two directions.

17. A clutch for lifting a te component, ing a toroidal connector, a latch in the form of a locking ring movable ve to the toroidal connector n a disengaged condition and an engaged condition, the locking ring having a handle extending radially outwardly from the toroidal connector, and a coupler for coupling the toroidal connector to a lifting apparatus, wherein the locking ring handle is arranged to abut the coupler to limit rotational movement of the coupler relative to the toroidal connector.

18. A clutch as claimed in claim 17, wherein the locking ring handle is arranged to limit rotational movement of the coupler relative to the toroidal connector such that said limit ts a tip of the locking ring handle passing through an inner loop of the coupler. A clutch for lifting a concrete component, including a toroidal connector, a latch in the form of a locking ring movable relative to the toroidal connector between a disengaged condition and an engaged condition, the locking ring having a handle extending radially outwardly from the toroidal connector, and a r for coupling the toroidal connector to a lifting apparatus, wherein the coupler includes a first part and a second part pivotal relative to the first part, the r being arranged to limit pivotal movement of the second part relative to the first part. 12