Patent Description:
It is known to provide a clutch for lifting concrete components 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 disadvantages 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 alleviates 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.

Earlier patent document <CIT> discloses a load gripping and carrying device for moving loads. The device includes a housing that is closed on all sides is formed from two circular parts that have an annular projection and a corresponding recess. A pin connected to the bolt protrudes from the housing on both sides and engages in two levers, the retaining bolts of which are arranged outside the imaginary centre point of the ring channel. The pin is slidably guided in longitudinal grooves of the lever.

According to the invention, there is provided a clutch for listing a concrete component as defined by the appended claims.

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 allowing direct fitment of a lifting hook.

It is preferred that the coupler includes an elongated pin about a longitudinal axis of which the second part is pivotal relative to the first part.

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

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 includes 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 perpendicular to a line connecting a centre of the first arc to a centre of the second arc.

There is also disclosed 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.

Preferably, the coupler is arranged to limit pivotal movement of the second part relative 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 against the second part at said limit.

The second part may include a shoulder arranged to bear against the first part at said limit.

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. 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 lifting apparatus, wherein the coupler includes a first part and a second part pivotal relative to the first part about a pin, and wherein the coupler 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 circular groove about its circumference and the tamper evident indicator includes a member in engagement with the circular groove to prevent movement of the pin along its longitudinal axis relative to the bush.

More preferably, 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 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 toroidal connector has a circular seat for sitting upon a circular upper surface of a head of and anchor coupled to the toroidal connector, wherein the circular seat terminates in a radial bearing surface for abutment with a castellation of the anchor.

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 bearing 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 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 locking ring handle is arranged to abut the coupler to limit rotational movement of the coupler relative to the toroidal connector.

Preferably, the locking ring handle is arranged to limit rotational movement of the coupler relative to the toroidal connector such that said limit prevents a tip of the locking 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 coupler 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 rotation of the second part relative to the first part in two directions.

The invention is further described by way of non-limiting example only with reference to the accompanying drawings, in which:.

As can be seen in <FIG> of the drawings, the present invention may provide an articulated clutch for lifting a concrete component. Advantageously, the articulated clutch has a coupler 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 <FIG>, there is provided a clutch <NUM> for lifting a concrete component (not shown). The concrete component may take several forms including, but not limited to, a concrete panel. The concrete component may have a cast in edge lift anchor (for example), the anchor having an eye which is used for connection to a toroidal connector of the clutch <NUM> for lifting the concrete panel.

The clutch <NUM> includes a toroidal connector <NUM> and a latch <NUM>. The latch <NUM> is movable relative to the toroidal connector <NUM> between a disengaged condition (in which the latch <NUM> is retracted into a toroidal sleeve of the toroidal connector <NUM>) and an engaged condition (see <FIG>) in which the latch <NUM> spans a gap of the toroidal connector <NUM> for engagement with an eye of and anchor cast into a concrete component. The clutch <NUM> also includes a coupler <NUM> for coupling the toroidal connector <NUM> to a lifting apparatus <NUM>, wherein the coupler <NUM> is articulated.

The coupler <NUM> includes a first part <NUM> and a second part <NUM> pivotal relative to the first part, the first part forming a first loop <NUM> engaged through the toroidal connector <NUM> and the second part <NUM> forming a second loop <NUM> for receiving the lifting apparatus <NUM>. As shown, the first loop <NUM> is a different size to the second loop <NUM>. More specifically, the first loop <NUM> is smaller than the second loop <NUM>. The second loop <NUM> is adapted to allow direct fitment of a lifting chain while also allowing direct fitment of a lifting hook. Accordingly, the coupler <NUM> allows the direct fitment of a suitable size chain like a hammerlock but also allows for direct fitment to a lifting hook as shown in <FIG>.

The articulation of this format of clutch handle (in the form of coupler <NUM>) 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 <NUM>° before being positioned. It does this while also meeting the needs of the precast factory where the clutch <NUM> 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 <NUM> and the second loop <NUM>) 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 limited by the gantry height.

As shown in <FIG>, the coupler <NUM> includes an elongated axle pin <NUM> about a longitudinal axis of which the second part <NUM> is pivotal relative to the first part <NUM>. The first part <NUM> includes a forked end and a non-forked end. The forked end of the first part <NUM> engages with a non-forked end of the second part <NUM>, whereas the non-forked end of the first part <NUM> engages with a forked end of the second part <NUM>. The ends of the first part <NUM> and the second part <NUM> are provided with apertures through which the axle pin <NUM> is passed so as to hold together in pivotal relationship the first part <NUM> and the second part <NUM>.

With reference to <FIG>, the latch <NUM> is in the form of a circular latch passing through an inner circular passage of the toroidal connector <NUM>. The latch <NUM> has a handle <NUM> for moving the latch <NUM> between the disengaged condition and the engaged condition, the handle <NUM> extending generally radially outwardly relative to a centre of the toroidal connector <NUM>.

As shown most clearly in <FIG>, the first part <NUM> has a first circular arc <NUM> and the second part <NUM> has a second circular arc <NUM>. The pin <NUM> is located such that a longitudinal axis of the pin <NUM> is perpendicular to a line <NUM> connecting a centre <NUM> of the first arc <NUM> to a centre <NUM> of the second arc <NUM>.

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

Turning to <FIG>, the latch <NUM> in the form of the locking ring may have a handle <NUM> extending generally radially outwardly from the toroidal connector <NUM>. The coupler <NUM> may be specifically arranged to limit pivotal movement of the second part <NUM> relative to the first part <NUM>. In other words, in <FIG> the first part <NUM> and the second part <NUM> are shown in a co-planar configuration, whereas in <FIG> there is shown a limit of pivotal movement of the second part <NUM> relative to the first part <NUM>.

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

As best shown in the cross-sectional drawing shown in <FIG>, the first part may include a shoulder <NUM> arranged to bear against the second part <NUM> at the limit. Alternatively, or in addition, the second part <NUM> may include a shoulder arranged to bear against the first part <NUM> at the limit.

In a preferred example, the coupler <NUM> is arranged to limit pivotal movement of the second part <NUM> relative to the first part <NUM> such that the limit prevents the second part <NUM> from engaging with the locking ring handle <NUM> to rotate the locking ring handle <NUM>. More specifically, the coupler <NUM> may be arranged to limit pivotal movement of the second part <NUM> relative to the first part <NUM> such that the limit prevents the second part <NUM> from engaging with the locking ring handle <NUM> to rotate the locking ring handle <NUM> from the engaged condition to the disengaged condition.

In this way, the two loops <NUM>, <NUM> are limited in rotation in one direction to eliminate the large loop being able to hook under the locking ring handle <NUM>. The applicant has identified that, where the upper loop (secondly <NUM>) is large enough to accept a lifting hook, then that loop has the potential to cook under the locking ring handle <NUM> and could allow the clutch <NUM> to become disconnected from the anchor unintentionally. Advantageously, by limiting rotation in this way examples of the present invention are able to prevent unintentional disconnection.

As shown in <FIG>, the second part <NUM> is pivotal relative to the first part <NUM> about the axle pin <NUM>. The coupler <NUM> may also include a tamper evident indicator <NUM> to indicate that the clutch <NUM> has not been disassembled. The tamper evident indicator may be is arranged to indicate that the axle pin <NUM> has not been removed from the coupler <NUM>. In the example shown, the coupler <NUM> is provided with a bush <NUM> around a central portion of the axle pin <NUM>, the central portion being between the distal end of the first part <NUM> and the second part <NUM>. The second part <NUM> may be provided with longitudinal slots which are received in corresponding longitudinal grooves of the bush <NUM> to keep the bush <NUM> aligned relative to the second part <NUM> and to prevent rotation of the bush <NUM> relative to the second part <NUM>.

With reference to <FIG>, the pin <NUM> may have a circular groove <NUM> about its circumference and the tamper evident indicator <NUM> may include a member in engagement with the circular groove <NUM> to prevent movement of the pin <NUM> along its longitudinal axis relative to the bush <NUM>. In addition, the toroidal connector <NUM> may be provided with a stop pin <NUM> to limit rotation of the latch <NUM> relative to the toroidal connector <NUM>. The member <NUM> may be anchored to the bush <NUM>. With reference to <FIG>, the member <NUM> may be in the form of a rivet which passes through the bush <NUM> and has a flange at each end to retain the rivet relative to the bush <NUM>. Alternatively, the member may be in the form of a roll pin.

In this way, there is provided a tamper evident centre bush <NUM>. The bush <NUM> may be profiled to match the loops <NUM>, <NUM>, the bush <NUM> being secured by either a rivet or a roll pin that does not pass through the middle of the axle pin <NUM> but passes tangentially through the groove <NUM> on the axle pin <NUM>. If secured by a rivet, the rivet will be deformed to secure it and the deformed end may have a branded logo (see <FIG> and <FIG>) to indicate the handle (coupler <NUM>) 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 <NUM> has not been disassembled.

As will be appreciated from the drawings, the bush <NUM> has a non-cylindrical shape. The locking pin or rivet <NUM> runs tangentially through the groove <NUM> in the axle pin <NUM>. Accordingly, this provides an indication to the user that the clutch <NUM> 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 happened. 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 <NUM> has not been tampered with since proof testing. The unique shape of the bush <NUM> allows the rivet or cross pin <NUM> to hold the axle <NUM> by the groove <NUM> rather than passing the centre of the axle <NUM>. This creates far less stress concentration, making the axle <NUM> stronger. The unique shape of the bush <NUM> also allows the use of the tamper evident rivet <NUM>. The tangentially positioned groove <NUM> allows for easier assembly of the system compared to that of a centrally located hole as less alignment is required (that is, alignment is only required in the x-axis and not in both x and y axes).

Turning now to <FIG>, the toroidal connector <NUM> may be provided with a circular seat <NUM> for sitting upon a circular upper surface <NUM> of a head <NUM> of an anchor <NUM> coupled to the toroidal connector <NUM>. The circular seat <NUM> terminates in a radial bearing surface <NUM> for face-to-face abutment with a castellation <NUM> of the anchor <NUM>.

As can be seen most clearly in <FIG>, the circular seat <NUM> has a first radial bearing surface <NUM> for abutment with a first castellation <NUM> of the anchor and a second, opposite, radial bearing surface <NUM> for abutment with a second castellation <NUM> of the anchor <NUM>.

In the example shown, the circular seat <NUM> is circular about an arc <NUM> having a centre at a central longitudinal (tangential) axis <NUM> of the latch <NUM>. More specifically, the radial bearing surface <NUM> is radial relative to a circle having a centre at the central longitudinal axis <NUM> of the latch <NUM>.

Advantageously, the provision of the radial bearing surfaces <NUM> improve the interface of the toroidal connector <NUM> and the anchor <NUM>, when compared with existing connectors which abut at an edge or point. The applicant has identified that the face-to-face bearing provides less pressure owing to the greater surface area of contact, reducing wear on the toroidal connector <NUM>. 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 invention shown, a new angled face interacts with the angled face of the anchor <NUM> 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 toroidal connector <NUM> which bear against the castellations <NUM> on the head <NUM> of the anchor <NUM>. 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 <FIG>, there is shown an alternative example of the present invention in which the locking ring handle <NUM> is arranged to abut the coupler <NUM> to limit rotational movement of the coupler <NUM> relative to the toroidal connector <NUM>. In particular, the locking ring handle <NUM> is arranged to limit rotational movement of the coupler <NUM> relative to the toroidal connector <NUM> such that the limit prevents a tip <NUM> of the locking ring handle <NUM> passing through an inner loop <NUM> of the coupler <NUM>. This may be achieved by dimensioning the locking ring handle <NUM> such that the tip <NUM> of the locking ring handle <NUM> extends radially further from a centre of the toroidal connector <NUM> than an outermost edge of the coupler <NUM>.

Turning to <FIG>, there is shown an example of the present invention in which the coupler <NUM> is arranged to limit pivotal movement of the second part <NUM> relative to the first part <NUM> in two directions. More specifically, as can be seen in <FIG>, the first part <NUM> is connected to the second part <NUM> by a pivotal coupling <NUM>. In the example shown, the pivotal coupling <NUM> includes a first hinge <NUM> at one side of the coupler <NUM> and a second hinge <NUM> at an opposite side of the coupler <NUM>. As can be seen, the first hinge <NUM> and the second hinge <NUM> are arranged to provide pivotal movement of the second part <NUM> relative to the first part <NUM> along a common axis which may be ensured by a single axle pin <NUM>.

In the example shown in <FIG>, the pivotal coupling <NUM> includes a bush <NUM> between the first hinge <NUM> and the second hinge <NUM>. The bush <NUM> includes a stop <NUM> for abutting against the first part <NUM> or the second part <NUM> to limit rotation of the second part <NUM> relative to the first part <NUM>. The bush <NUM> may be arranged to rotate with the second part <NUM> (for example, engaged with the second part <NUM> by way of a tongue and groove connection) and the stop <NUM> may be adapted to abut against the first part <NUM> to limit rotation of the second part <NUM> relative to the first part <NUM>.

<FIG> shows an enlarged and detailed view of the portion labelled "B" in <FIG>. In <FIG> it can be seen that the first part <NUM> is provided with a tab <NUM> for abutment with the stop <NUM>.

<FIG> shows a front view of the coupler <NUM>, and <FIG> shows an enlarged and detailed view of the cross-section labelled A-A in <FIG>. With reference to <FIG>, the stop <NUM> may be in the form of a cutout <NUM> having two stop surfaces, comprising a first stop surface <NUM> for abutting one side of the tab <NUM> and a second stop surface <NUM> for abutting an opposite side of the tab for limiting rotation of the second part <NUM> relative to the first part <NUM> in two directions.

Advantageously, this arrangement enables the limiting of angular movement of the second part <NUM> relative to the first part <NUM> 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 <NUM> and/or the second hinge <NUM>. The arrangement shown in <FIG> takes advantage of there being no load or only little load on the coupler <NUM> when the rotation limiting mechanism is required to perform its duty. In other words, the arrangement shown in <FIG> 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 <NUM> that limit the movement 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 between the lower loop - the first part <NUM> - and the centre bush <NUM>, where the centre bush <NUM> is keyed to the upper bush to maintain alignment with the upper loop.

Claim 1:
A clutch (<NUM>) for lifting a concrete component, including a toroidal connector (<NUM>), a latch (<NUM>) movable relative to the toroidal connector between a disengaged condition and an engaged condition, and a coupler (<NUM>) for coupling the toroidal connector to a lifting apparatus (<NUM>), wherein the coupler is articulated and includes a first part (<NUM>) and a second part (<NUM>) pivotal relative to the first part, the second part forming a second loop (<NUM>) for receiving the lifting apparatus
characterised in that the first part (<NUM>) forms a first loop (<NUM>) engaged through the toroidal connector (<NUM>).