GB2583458A

GB2583458A - Cage vibrator

Info

Publication number: GB2583458A
Application number: GB1904826.3A
Authority: GB
Inventors: Igor Malinowski Jakub
Original assignee: Dawson Construction Plant Ltd
Current assignee: Dawson Construction Plant Ltd
Priority date: 2019-04-05
Filing date: 2019-04-05
Publication date: 2020-11-04
Anticipated expiration: 2039-04-05
Also published as: GB2583458B; GB201904826D0

Abstract

A cage clamp 2 comprises a base 4 a mandrel 6 a clamp 8a, 8b, 8c wherein the mandrel and the clamp are mounted to the base. A pile driver is couplable to the base in vibratory engagement to allow mutual vibration between the pile driver and the base. The clamp is operable to clamp the pile reinforcing cage 24 in a space between the mandrel and the clamp by actuating the clamp towards the mandrel. The pile driver may be coupleable to a first side of the base and the mandrel and clamp to a second side. There may be three clamps and clamp pads 16a, 16b, 16c may be provided on each clamp. A tapered guide member 14 may be provided to guide the cage into the space between the clamps and the mandrel.

Description

CAGE VIBRATOR

This invention relates to a cage clamp.

Background of the Invention

Bored Piles or Continuous Flight Auger (CFA) piles are a common type of foundation pile and are constructed by means of a piling rig that drills a hole into the ground. The hole is then filled with concrete and a steel reinforcing cage, known as a rebar cage, is plunged into the wet concrete residing within the hole. Typical pile sizes have diameters ranging from 400mm -1500mm and are between 5 -50m deep. Upon plunging the reinforcing cage into the hole, the cage is often unable to fully penetrate the wet concrete under its own weight. In these cases, the wet concrete may set with the cage partially installed and the pile will need to be removed and remade.

Generally, to aid with this problem, a vibratory pile driver is attached to the reinforced cage to aid the penetration of the cage within the wet concrete. The pile driver comprises a hydraulic clamp that is used to engage a reinforced cage that is to be driven. These standard industry clamps are designed for steel piles and will not clamp onto a reinforcing cage. Typical remedies for this problem are to weld a flat plate onto the cage to provide a clamp face for the pile driver or to fashion a circular sleeve that drops over, and is mounted to, the cage with a similar flat plate welded to the top of the sleeve. These remedies carry time, cost and are technically questionable, as these types of site fixes" do not provide an optimal interface for the use of vibratory power.

The present invention aims to overcome or at least ameliorate one or more of the problems set out above.

Summary of the Invention

In a first aspect of the invention, there is provided a cage clamp for connecting a pile driver to a cage, the cage clamp comprising: a base; a mandrel; and a clamp, wherein the mandrel and clamp are mounted to the base, and the pile driver is couplable to the base in vibratory engagement to allow mutual vibration between the pile driver and base; and wherein the clamp is operable to clamp cage material placed in a space between the mandrel and the clamp by actuating the clamp in a first direction towards the mandrel.

In this way, 'site fixes' of providing a clamping face on a cage for a pile driver can be replaced with the cage clamp The cage clamp provides an optimal interface for the engagement between a vibratory pile driver and a cage structure to allow efficient application of vibratory power from the pile driver to the cage allowing mutual vibration between the pile driver and the cage.

Favourably, the mandrel is removeable and/or the size of the mandrel is adjustable such that variations in the size of the cage can be accommodated by an appropriately sized mandrel. In this way, the mandrel can be replaced with a mandrel of a larger or smaller diameter depending on the preference of the user to allow the cage clamp to accommodate cages of a variety of diameter sizes.

Preferably, the pile driver is couplable to a first side of the base, and the mandrel and clamp are mounted to a second side of the base. In this way, attachment of a pile driver to the cage clamp is made simple by directing attached to a first side of the base while the mandrel and clamp can be positioned suitably towards a cage on a second side of the base.

Advantageously, the clamp comprises a clamp pad and a means for actuation of the clamp pad, in a first direction, towards the mandrel.

Favourably, the cage clamp further comprises a frame mounted to the base on a same side as the mandrel and clamp, wherein the frame protrudes axially from the base and extends beyond the mandrel and clamp. In this way, during the operation of the cage clamp, the frame will inevitably contact the ground surrounding a pile, preventing the other components of the cage clamp, i.e. the clamp and mandrel, from being damaged by the wet concrete of the pile.

Preferably, the mandrel and/or base comprise a guiding member arranged to guide cage material to within the space between the mandrel and the clamp. In this way, cage material that is placed upon a guiding member will be directed towards the space between the clamp and mandrel such that it can subsequently be clamped. This helps to suitably orientate the cage material with respect to the cage clamp, to allow optimal engagement of the cage clamp with the cage material.

Advantageously, the clamp pad can be actuated, in a second direction, towards the frame. In this way, the cage clamp has greater flexibility with respect to the diameter sizes of cages it can accommodate and clamp.

Favourably, the base is substantially planar. In this way, a suitably flat interface for a vibratory mechanism to attach to, for example a vibratory pile driver, is provided.

Preferably, the mandrel comprises a tapered surface arranged to guide cage material to within the space between the mandrel and the clamp. In this way, cage material that is placed upon the tapered surface of the mandrel will be directed towards the space between the clamp and mandrel such that it can subsequently be clamped. This helps to suitably orientate the cage material with respect to the cage clamp, to allow optimal engagement of the cage clamp with the cage material.

Advantageously, the frame comprises a tapered surface arranged to guide cage material to within the space between the mandrel and the clamp. In this way, cage material that is placed upon the tapered surface of the frame will be directed towards the space between the clamp and mandrel such that it can subsequently be clamped. This helps to suitably orientate the cage material with respect to the cage clamp, to allow optimal engagement of the cage clamp with the cage material.

Favourably, the clamp is mounted to the base via the frame. In this way, the frame may serve to aid in the ease of the manufacture of the cage clamp, for example allowing easier positional alignment of a plurality of clamps with respect to the mandrel.

Brief Description of the Drawings

Embodiments of the invention will now be described by way of example, with reference to the drawings in which:-Figure 1 is a perspective view of the cage clamp attached to both a vibratory pile driver and a reinforced cage; Figure 2 is a perspective view of the top face of the cage clamp in Figure 1; Figure 3 is a perspective view of the top face of the cage clamp without a vibratory pile driver and a reinforced cage attached; and Figure 4 is a magnified perspective view of the cage clamp in Figure 1.

Detailed Description

An embodiment of the present invention is described below, and would typically be used to provide an optimal interface for the engagement between a vibratory pile driver and a cage structure to allow efficient application of vibratory power from the pile driver to the cage allowing mutual vibration between the pile driver and the cage, such that the cage can be driven into the wet concrete of a pile foundation.

With reference to Figures 1 and 2 and 3, a cage clamp 2 comprises a base 4, a mandrel 6 and clamps 8a, 8b, 8c. The base 4 is substantially planar, having a top face 11 and a bottom face 10, with the mandrel 6 and clamps 8a, 8b, 8c being mounted to the bottom face 10. The substantially planar shape of the base 4 provides a suitably flat interface for a vibratory mechanism to attach to, for example a vibratory pile driver 3. More specifically, the gearbox 5 of a vibratory pile driver 3 is bolted onto the top face 11 of the base via the bolting plate 7 using a plurality of bolts 9. Here, the cage clamp 2 replaces standard industry clamping mechanisms that are typically used with vibratory mechanisms for driving a reinforced cage into the wet concrete of a pile foundation.

A crane (not shown) can be used to manipulate the gearbox 5, and thus the cage clamp 2. As illustrated by Figure 2, a saddle 32 is able to mount the gearbox 5 to a lifting beam 30, whereby the saddle 32 is mounted to the gearbox 5 using a plurality of bolts 9, and to the beam 30 via mounting arrangement 34. The crane can subsequently be used to manipulate the beam 30, and thus the cage clamp 2, using cables 38a via a crane hook 36. A separate set of cables 38b is attached from the beam 30 to the cage 26, to aid in the lifting of the cage at a jobsite and plunging them into wet concrete, before the driving process.

The base 4 is typically a high tensile strength material, for example an alloy such as steel, such that its structural integrity is not compromised by the mounting and weight of the mandrel 6 and clamps 8a, 8b, 8c, and the clamping forces induced on the base 4 by the pile driver 3. In other embodiments, the base 4 may not be substantially planar and may have more faces than just a top face 11 and bottom face 10.

The mandrel 6 has a substantially hemi-spherical shape and is generally concentric with the base 4. The peripheral face of the mandrel 6 defines a contact surface 12 extending, circumferentially, around the mandrel 6 and is substantially vertical with respect to the horizontal plane of the base 4 upon which the mandrel 6 is mounted. The end of the contact surface 12 distal from the base 4 converges via a tapered surface 14, the function of which will be discussed further below. In other embodiments, the mandrel 6 may not comprise a tapered surface 14 and the contact surface 12 instead converges via right angles such that the mandrel 6 resembles a substantially cylindrical shape. In some cases, the mandrel 6 may not be concentric with the base 4, and instead have an eccentric positioning.

The cage clamp 2 further comprises the frame 20 which is mounted to the base 4. The frame 20 is substantially circular in shape and has a larger diameter than the mandrel 6 such that the mandrel 6 resides within the frame 20. The diameter of the frame 20 is also larger than the typical diameter size of a pile foundation. The size of the diameter of the frame 20 can be determined during the manufacturing stage of the cage clamp 2 depending on the diameter size of the pile the cage clamp 2 will be used for.

The frame 20 extends axially from the base 4 to a distal end that protrudes beyond the other components mounted to the bottom face 10 of the cage clamp 2, i.e. the clamps and mandrel etc. In other embodiments, the clamps 8a, 8b, 8c may be mounted to the base 4 via the frame 20. In this case, the frame 20 may serve to aid in the ease of the manufacture of the cage clamp 2, for example allowing easier positional alignment of the clamps 8a, 8b, 8c with respect to the mandrel 6. The primary function of the frame 20 will be discussed further below.

The clamps 8a, 8b, 8c are equidistant with respect to one another and are identical, both in structure and in function. Therefore, only one of the three clamps 8a, 8b, 8c will be described. The clamp 8a comprises a clamp pad 16a and an actuation means 18a, for example an electric, pneumatic or hydraulic cylinder, such that the clamp pad 16a of the clamp 8a can be actuated. Here, a separate electric, pneumatic or hydraulic motor can be connected to, and supply, both the gearbox 5, of the pile driver 3, and the actuation means 18a, of the clamp 8a, with power and lubrication. In some cases, the actuation means 18a may house the motor.

The clamp pad 16a faces the mandrel 6, and comprises a body with a concave partially rectangular surface to correspond to the shape of the contact surface 12 of the mandrel 6.

Actuation of the pad 16a, by the actuation means 18a, in a first direction, towards the mandrel 6, clamps the pad 16a against the mandrel 6. The complementary shaping of the pad 16a and contact surface 12 help to ensure the entire surface area of the pad 16a will contact, and clamp against, the corresponding surface area of the contact surface 12 when the pad 16a is actuated. In other cases, the clamps 8a, 8b, 8c may not be equidistant with respect to one another.

Referring to Figure 4, the cage clamp 2 is considered to be in a neutral state when the clamp pad 16 is in a retracted position, i.e. before actuation of the pad 16a, such that there is space between the pad 16a and mandrel 6. The space between the pad 16a and the corresponding surface area of the contact surface 12, against which the pad 16a will clamp, defines a clamping zone 22a. Here, any material placed within the clamping zone 22a will be clamped against the mandrel 6 when the clamp 8a is subsequently actuated, thus restricting the movement of the captured material. Cage material, in particular the ends of the cage rods 26 of a cage 24, placed within the clamping zone 22a will be clamped against the mandrel 6, restricting any unwanted movement of the cage 24, both axially and radially with respect to the elongate length of the cage 24. In other words, the clamp 8a is operable to clamp cage material placed in a space between the mandrel 6 and the clamp 8a by actuating the clamp 8a, in particular the clamp pad 16a, towards the mandrel.

The terms "material" or "cage material" refer to any material of, or any structural parts of, a cage 24 that is to be used in conjunction with an embodiment of the present invention. Generally, in the context of the present embodiment, the cage 24 is used to form part of a pile foundation and is a stable elongate structure of bars and wires that is typically driven into the wet concrete of a pile foundation to provide structural support and increase the bearing capacity of the pile. More specifically, the cage 24 comprises elongate cage rods 26 that are bound with respect to the one another in a cylindrical arrangement (illustrated by Figures 1 and 3) such that the cage 24 is structurally reinforced and stable. The cage 24 is typically a high tensile strength material, for example an alloy such as steel.

In other embodiments, the mandrel 6 may not be substantially hemi-spherical, but any other suitable shape such that a clamp pad 16a, 16b, 16c is able to make suitable contact with, and clamp, cage material, placed between the pad 16, 16b, 16c and mandrel 6, against the mandrel 6 to secure the cage material in place. Similarly, in some cases, the shape of the clamp pad 16a, 16b, 16c may be any other suitable shape such that a clamp pad 16a, 16b, 16c is able to make suitable contact with, and clamp, cage material, placed between the pad 16a, 16b, 16c and mandrel 6, against the mandrel 6 to secure the cage material in place. In other cases, the clamps 8a, 8b, 8c and/or clamp pads 16a, 16b, 16c may be of differing sizes and shapes with respect to one another.

Accordingly, the space between the clamp pads 16a, 16b, 16c, of each of the clamps 8a, 8b, 8c, and the contact surface 12 of the mandrel 6 define a plurality of clamping zones 22a, 22b, 22c. Material placed outside of the clamping zones, i.e. in the space in-between proximate clamping zones, is not captured by either of the corresponding clamps. The overall spatial distribution of the clamping zones 22a, 22b, 22c, with respect to one another in the longitudinal plane of the base 4, can be considered to resemble an overall ring clamping zone that is substantially castellated, and surrounds the exterior contact surface 22 of the mandrel 6. Here, the troughs of the castellated ring represent the clamping zones 22a, 22b, 22c, and the peaks represent non-clamping zones.

Placing a cage 24, in particular the ends of the cage rods 26, within the overall ring clamping zone, will result in a number of the rods 26 being placed within each of the clamping zones 22a, 22b, 22c. In this way, with the cage 24 placed within the clamping zones 22a, 22b, 22c and upon subsequent actuation of the clamps 8a, 8b, 8c, the cage clamp 2 is able to firmly clamp onto a cage 24 via the clamp pads 16a, 16b, 16c and mandrel 6. The diameter of this overall ring clamping zone can therefore be manufactured, via the mandrel and clamps, to correspond to cages 24 of varying sizes, i.e. varying diameter sizes of the cage 24.

In order to accommodate the case where a cage 24 is placed within the overall ring clamping zone and a cage rod 26 falls within a non-clamping zone, the mandrel 6 further comprises guiding members 28a, 28b, 28c to aid in guiding these particular rods to within one of the clamping zones 22a, 22b, 22c. The guiding members 28a, 28b, 28c protrude radially, with respect to the mandrel 6, and into corresponding non-clamping zone areas.

Each guiding member 28a, 28b, 28c comprises a body that tapers outwardly towards both the base 4, and each corresponding clamping zone that is proximate to that particular guiding member. In this way, the ends of cage rods 26 that are placed upon a guiding member will be directed towards neighbouring clamping zones such that they can subsequently be clamped.

The tapered surface 14 of the mandrel 6 has a similar function to that of the guiding members 28a, 28b, 28c in that rods 26 placed on this surface 14 will also be directed towards one of the clamping zones 22a, 22b, 22c, either directly, or indirectly via a guiding member 28a, 28b, 28c. For example, placing the end of a cage rod 26 on the guiding member 28a will guide the rod 26 towards one of the proximate clamping zones 22a, 22b.

Directing the rods 26 using the tapered surface 14 and guiding members 28a, 28b, 28c helps to suitably orientate the cage 24 with respect to the cage clamp 2, to allow optimal engagement of the cage clamp 2 with the cage 24.

In this embodiment, as there are three clamps 8a, 8b, 8c, three clamping zones are defined, as well as three corresponding non-clamping zones. In other embodiments, the cage clamp 2 may comprise a greater, or fewer, number of clamps such that greater, or fewer, clamping zones are defined. The particular number of clamps a cage clamp 2 comprises can be determined during the manufacturing stage of the cage clamp 2. A greater number of clamps may allow the cage clamp 2 to more securely capture a greater number of cage rods 26 thus providing a more secure clamping mechanism. Contrastingly, having fewer clamps may degrade the clamping ability of the cage clamp 2 but allow for a simpler and more inexpensive manufacture of the cage clamp 2. The number of clamps a cage clamp 2 will be manufactured with will depend on what type of cage 24 the cage clamp 2 will be used for, and be a balance between inexpensive manufacture and suitable clamping ability.

Ideally, the number of guiding members a cage clamp 2 comprises will correspond to the number of clamps the cage clamp 2 has such that all non-clamping zone areas have a corresponding guiding member. In some cases, it may be desirable to have the number of guiding members not correspond to the number of clamps a cage clamp 2 comprises. In this embodiment, the guiding members 28a, 28b, 28c form part of the mandrel 6, but in some cases, the guiding members 28a, 28b, 28c may be a separate structure that is mounted onto the base 4 and/or mandrel 6.

Primarily, the diameter of the mandrel 6 determines what size cage 24, with respect to the diameter of the cage 24, the cage clamp 2 will optimally clamp onto and secure. The spacing of the clamp pads 16a, 16b, 16c, with respect to the contact surface 12 of the mandrel, via the diameter of the frame 20, will also contribute to this determination. This is because both the size of the mandrel, and the spacing of the pads, determine the area of the clamping zones 16a,16b,16c. To allow the cage clamp 2 to accommodate cages of a variety of sizes, in diameter, the mandrel 6 is a removable component of the cage clamp 2. Therefore, the mandrel 6 can be replaced with a mandrel of a larger or smaller diameter depending on the preference of the user, i.e. if a cage to be clamped has a proportionally larger or smaller diameter than the mandrel already mounted to the base 4 of the cage clamp 2. In other embodiments, the size of the mandrel 6 may be adjustable such that it is not necessary to replace the mandrel 6, and instead the diameter of the mandrel 6 can be increased or decreased while the mandrel 6 remains mounted to the base 4. In yet further embodiments, the mandrel 6 may be both removeable and adjustable.

In this embodiment, the space between the clamps 8a, 8b, 8c and mandrel 6 defines the clamping zones 22a, 22b, 22c, and the actuation of the clamp pads 16a, 16b, 16c in a first direction, towards the mandrel 6, clamps cage material placed within the clamping zones 22a, 22b, 22c against the mandrel 6. In other embodiments, the clamping zones may be defined between the clamps 8a, 8b, 8c and the frame 20, and the clamp pads 16a, 16b, 16c may be actuated in a second direction, towards the frame 20, such that cage material placed within the newly defined clamping zones will become clamped against the frame 20. In this case, the diameter of the frame 20 will more greatly contribute in determining what size of cage 24 the cage clamp 2 will optimally clamp onto. In other cases, the cage clamp 2 is able to clamp cage material in both a first direction, against the mandrel 6, and a second direction, against the frame 20. In yet other cases, the clamping zones may be defined between the mandrel 6 and frame 20, and the frame 20 may be tapered such that cage material that contacts the frame 20 is guided into the corresponding clamping zone.

The pile driver 3 is couplable to the base 4 of the cage clamp 2 in vibratory engagement such that when the pile driver vibrates, so does the base 4, and thus the cage clamp 2. In other words, when the pile driver 3 is coupled to the base 4 in vibratory engagement, mutual vibration between the pile driver 3 and base 4 occurs. With a vibratory pile driver 3 bolted onto the top face 11 of the cage clamp 2, and the cage clamp 2 clamped onto a cage 24, via the clamps 8a, 8b, 8c, the cage clamp 2 allows mutual vibration of the cage 24 and pile driver 3 to occur upon the application of the vibratory power of the pile driver 3. The interface between the pile driver 3 and cage 24, provided by the cage clamp 2, permits efficient application of the vibratory power from the pile driver 3. In this way, as the pile driver 3 vibrates, the base 4 of the cage clamp 2, and thus the clamped cage 24, also vibrates. The cage clamp 2 facilitates mutual vibration between the pile driver 3 and clamped cage 24 such that the cage 24 may be driven into the wet concrete of a pile.

During the operation of the cage clamp 2 in driving a cage 24 into the wet concrete of a pile foundation, the frame 20 serves to protect the other mounted components of the cage clamp 2, in particular the moving parts such as the clamps, from being plunged into the wet concrete of a pile along with the cage 24. As the frame 20 protrudes axially from the base beyond the other components mounted to the bottom face 10 of the cage clamp 2, and the diameter of the frame 20 is larger than the diameter of the pile, as a cage 24 is further plunged into the pile, the frame 20 will inevitably contact the ground surrounding the pile, preventing the other components of the cage clamp 2, i.e. the clamps 8a, 8b, 8c and mandrel 6, from being damaged by the wet concrete of the pile.

Considering now a cage clamp 2 that is not clamped to pile driver 3 and in a neutral state, i.e. the clamp pads 16a, 16b, 16c are in a retracted position and not actuated and clamped against the mandrel 6, the pile driver 3 is bolted onto the top face 11 of the cage clamp 2, via the bolting plate 7, and the rods 26 of a cage 24 are placed within the clamping zones 22a, 22b, 22c of the cage clamp 2, such that the ends of the rods 26 within the zones contact the bottom face 10 of the base 4. The pile driver 3 and cage clamp 2 are then supplied with power, from an external motor, and the cage clamp 2 is operated such that the clamp pads 16a, 16b, 16c are actuated and move in a first direction, towards the mandrel 6, and clamp the cage 24 against the mandrel 6. The cage clamp 2 is then positioned over the wet concrete of a pile and the vibratory power of the pile driver 3 is applied. Upon the application of the vibratory power of the pile driver 3, mutual vibration of the pile driver 3 and base 4, and thus cage 24, occurs, and the vibrating cage 24 is then plunged into the wet concrete of a pile, at an end of the cage 24 distal from the cage clamp 2, such that the cage 24 penetrates the wet concrete of the pile. Subsequently, once the frame 20 engages the ground and/or a user is satisfied with the placement of the cage 24, the vibratory power of the pile driver 3 is disengaged, and the cage clamp 2 is then operated such that the clamp pads 16a, 16b, 16c return to a retracted position, releasing the cage 24 from the cage clamp 2, and readying the cage clamp 2 for subsequent use.

Claims

CLAIMS1. A cage clamp for connecting a pile driver to a cage, the cage clamp comprising: a base; a mandrel; and a clamp, wherein the mandrel and clamp are mounted to the base, and the pile driver is couplable to the base in vibratory engagement to allow mutual vibration between the pile driver and base; and wherein the clamp is operable to clamp cage material placed in a space between the mandrel and the clamp by actuating the clamp in a first direction towards the mandrel.
2. A cage clamp according to claim 1, wherein the mandrel is removeable and/or the size of the mandrel is adjustable such that variations in the size of the cage can be accommodated by an appropriately sized mandrel.
3. A cage clamp according to claim 1 or 2, wherein the pile driver is couplable to a first side of the base, and the mandrel and clamp are mounted to a second side of the base.
4. A cage clamp according to claim 3, wherein the first side of the base is couplable to a beam, and the pile driver is couplable to the first side of the base via the beam.
5. A cage clamp according to claim 4, wherein the first side of the base is couplable to a gearbox, and the first side of the base is couplable to the beam via the gearbox.
6. A cage clamp according to any of the preceding claims, wherein the clamp comprises a clamp pad and a means for actuation of the clamp pad, in a first direction, towards the mandrel.
7. A cage clamp according to any of the preceding claims, further comprising a frame mounted to the base on a same side as the mandrel and clamp, wherein the frame protrudes axially from the base and extends beyond the mandrel and clamp.
8. A cage clamp according to any of the preceding claims, wherein the mandrel and/or base comprise a guiding member arranged to guide cage material to within the space between the mandrel and the clamp.
9. A cage clamp according to claims 7 or 8, wherein the clamp pad can be actuated, in a second direction, towards the frame.
10. A cage clamp according to any of the preceding claims, wherein the base is substantially planar.
11. A cage clamp according to any of the preceding claims, wherein the mandrel comprises a tapered surface arranged to guide cage material to within the space between the mandrel and the clamp.
12. A cage clamp according to any of claims 7 -11, wherein the frame comprises a tapered surface arranged to guide cage material to within the space between the mandrel and the clamp.
13. A cage clamp according to any of claims 7 -12, wherein the clamp is mounted to the base via the frame.