GB2159205A - Apparatus for and a method of demolishing stacks - Google Patents

Abstract

Apparatus for demolishing stacks and similar structures comprising a breaker 1, means for adjusting the position of the breaker, a cradle 12 having a plurality of arms 13, 14, 15, 16 radiating from a central point upon which the breaker and adjusting means are mounted first rope means 23,24,25 and second hook means 37 for suspending the cradle 12 within a stack connected to the end of each of said arms 13, 14, 15, 16 and means 26, 27, 28, 29 for transferring the weight of the cradle 12 from each of the first suspension means 23, 24, 25 to each of the second suspension means 37. A method of demolishing a stack or similar structure using the above apparatus is also disclosed. <IMAGE>

Description

SPECIFICATION Apparatus for and a method of demolishing stacks The present invention relates to an apparatus for demolishing stacks and similar structures, and also to a method of demolishing stacks and similar structures using the apparatus, the apparatus and method being particularly suited to the demolition of concrete stacks.

Brick stacks have not really presented a problem when it comes to demolition as it is a relatively simple matter for steeplejacks working around the head of the stack to break the bricks away using hand-held tools and equipment, such as hand held pneumatically-operated hammers or breakers. Even with light hand-held equipment and tools the bricks are easily broken away from their mortar bonding with the result that demolition progresses quickly and efficiently. However, it is increasingly the case that the more recently constructed concrete stacks require demolition, due, for example, to redundancy or to unsafeness. Using the conventional techniques and equipment applied to brick stacks, the job of demolishing these concrete stacks is long, laborious and expensive.Quite simply it is impossible to make the same rate of progress through concrete as it is though brick using hand-held equipment, and using conventional techniques it is impossible to get existing heavy duty breakers into a position where they could be used in the demolition of these concrete stacks.

It is an object of the present invention to provide an apparatus for the demolition of stacks and similar structures which enables the use of heavy duty breakers.

It is a further object of the present invention to provide a method of demolishing stacks and similar structures using the apparatus.

According to a first aspect of the present invention there is provided an apparatus for demolishing stacks and similar structures comprising a breaker, means for adjusting the position of the breaker, a cradle having a plurality of arms radiating from a central point upon which the breaker and adjusting means are mounted, first and second means for suspending the cradle within a stack connected to the end of each of said arms and means for transferring the weight of the cradle from each of the first suspension means to each of the econd suspension means.

Preferably, the breaker and means for adjusting the slew and elevation thereof are hydraulically operated.

Preferably, the breaker is mounted on a telescopic arm which is hydraulically extended and retracted.

Preferably, means are provided for automatically extending the telescopic arm during use to keep the breaker up to the surface on which it is working.

Preferably, the means for automatically extending the telescopic arm comprises a diaphragm, a one-way valve and a compressed air source, the diaphragm allowing air to be drawn through the one-way valve from the compresssed air source whenever the pressure on the breaker drops below a preset level.

Preferably the cradle comprises four arms.

Preferably, a hydraulically-operated jack is provided at the end of each of said arms to brace the cradle against the walls of the stack when the breaker is in use.

Preferably, each of said arms carries a gallows-shaped structure which extends above the top of and beyond the edge of the stack, from the upper end of which a platform structure, which circles around the outside of the stack, is suspended to catch falling debris.

Preferably, the first suspension means comprises a rope or cable, one end of which is adapted to be secured to the outside wall of the stack at a point below the current level of demolition, and the other end of which is connected to the said weight-transferring means which comprises means for raising and lowering the cradle relative to the rope.

Preferably, the means for raising and lowering the cradle relative to the rope comprises a two-way ratchet arrangement mounted on each arm of the cradle through which the rope can be passed back and forth, and locked in place. Such an arrangement is sometimes referred to as a tirfors.

Preferably, the second suspension means comprises a hook member which can be hooked over the side of the stack and connected to a respective arm of the cradle.

According to a second aspect of the present invention there is provided a method of demolishing a stack or a similar structure in which a breaker having adjustable slew and elevation is mounted at the centre of a plurality of arms extending from a central point to form a cradle, the cradle is suspended within the stack on first suspension means extending from the end of each of said arms to a point of anchorage outside the stack, embrasures are cut in the top of the stack between the said arms such that the positions of the cops correspond with the positions of the arms and with the positions of the first suspension means, second suspension means are connected between the end of each arm and the bottom of a respective embrasure, the weight of the cradle is transferred from the first suspension means to the second suspension means, the cops are cut down and the weight of the cradle is transferred from the second suspension to the first suspension means.

Preferably the stack is demolished in such a way that portions therefrom fall into the stack between the arms of the cradle.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a side view of a hydraulically operated hammer or breaker for use in apparatus according to the first aspect of the present invention; Figure 2 shows a perspective view of a cradle adapted to support the breaker of Fig.

1 and for use in apparatus according to the first aspect of the present invention; and Figure 3 shows a schematic view of apparatus according to the first aspect of the present invention suspended within a stack which illustrates the method according to the second aspect of the present invention.

Referring to Fig. 1 of the accompanying drawings there is shown a heavy duty hydraulically-operated hammer or breaker 1 carrying a tool 2 for breaking concrete. Operating of the breaker 1 to drive the tool 2 is conventional and therefore a detailed explanation thereof is not necessary here. The breaker 1 is mounted on the reciprocating member 3 of a hydraulically-operated telescopic arm 4, which is adapted, as will be explained further hereinbelow, to be progressively extended during use to keep the breaker 1 and specifically the tool 2 up to the surface to be broken. In turn the telescopic arm 4 is pivotally mounted by means of a bracket 5 on a support 6, which is in its turn rotatably mounted on a pedestal 7.

The elevation of the telescopic arm 4 is adjusted by pivoting it up or down about the support 6 and to this end a hydraulic cylinder 8 is pivotally connected at each end between the support 6 and the opposite end of the arm 4 from the breaker 1. Thus, the position of the tool 2 about a horizontal axis can be adjusted by extending or retracting the piston 9 of the hydraulic cylinder 8. Rotation of the support 6 relative to the pedestal 7 is controlled by means of a pair of hydraulicallyoperated ratchet and pinion mechanisms 10 and 11 and thus the position of the tool 2 about a vertical axis can also be adjusted.

It will be appreciated that in Fig. 1 the controls and hydraulic hoses by means of which the breaker 1, the telescopic arm 4, the cylinder 8 and the ratchet 10 and 11 are controlled and operated have been omitted for the sake of clarity. However, having regard to the telescopic arm 4, it should be pointed out that this makes use of a special feature of the present invention to ensure that the reciprocating member 4 is progressively extended during use to keep the breaker 1 and specifically the tool 2 up to the surface to be broken. Although not shown, the telescopic arm is supplied with compressed air via a oneway valve and diaphragm arrangement in such a way that each time the pressure at the tool 2 drops below a preset level to indicate the breaker can move forward, the diaphragm allows more compressed air to be supplied to the telescopic arm.

Referring to Fig. 2 there is shown a cradle structure 1 2 consisting of four arms 13, 14, 1 5 and 1 6 which radiate from a central point at which is provided a steel stool 1 7. The stool 1 7 is provided with a number of bolts (not shown) and by means of these the pedestal 7 (see Fig. 1) is secured to the cradle 1 2.

In the arrangement of Fig. 2, the four arms are formed by one long I-section bar and two shorter I-section bars secured to respective sides of the longer bar. However, it will be realised that other constructions are possible, and, moreover, that other configurations such as three arms or more than four arms are possible.

Mounted at the end of each arm 13,14,1 5 and 1 6 is a suspension ring 18,19, 20 and 21, through each of which is passed a rope or cable 22, 23, 24 and 25. In use, one end of the rope is adapted to be anchored outside the stack to be demolished, below the current level of demolition. The other end of the rope passes through a hand-operated two-way ratchet mechanism 26, 27, 28 and 29 (sometimes known as a tirfor) which each allows the rope associated with it to be pulled through under tension or slackened off, and which also allows the rope to be locked in position.

Thus when the cradle 1 2 is suspended within a stack, it may be raised or lowered to any level within the stack on the ropes 22, 23, 24 or 25 using the mechanisms 26, 27, 28 and 29.

At the end of each arm 13,14,15 and 16 there is also provided a hand-operated hydraulic jack 30, 31, 32 and 33. The breaker 1 which can be mounted on the cradle 1 2 is very heavy duty and accordingly it exerts a very considerable amount of force. However, this force can only be effectively harnessed to demolish a stack if the cradle provides a firm and stable base within the stack. By pumping the jacks 30, 31, 32 and 33 until they engage with the walls of the stack, the cradle 1 2 can be held securely in position.

Although not shown, each of the arms 13, 14, 1 5 and 1 6 also has provision for the securing to it of a gallow-shaped structure which extends above the top of and beyond the edge of the stack. From the free end of each gallows, a platform is suspended which circles around the outside of the stack and catches any debris which may fall outside the stack, instead of inside where it is intended to fall.

Referring now to Fig. 3, operation of the apparatus according to the first aspect of the present invention in accordance with the method of the second aspect of the present invention will now be described.

In use, the cradle of Fig. 2, with the arrangement of Fig. 1 secured to it, is suspended within the stack 34 to be demolished, approximately 8 to 10 feet below the top of the stack 34, on the ropes 22, 23, 24 and 25. Then, making use of the ability of the arrangement of Fig. 1 to rotate, and to move up and down, four embrasures 35 and 36 (in Fig. 3 only two are shown) are cut in the top of the stack between the arms 13, 14, 1 5 and 1 6 and between the ropes 22, 23, 24 and 25. Where the stack 34 is of concrete, steel reinforceing bars will usually be present.

In this case two vertical cuts, joined at the bottom by a horizontal cut are made in the top of the stack. Then using appropriate equipment the horizontally disposed bars are cut. At this stage there is usually enough play in the block to be removed for it to be pushed in towards the centre of the stack at which point the vertically disposed bars may be cut and the block allowed to fall into the bottom of the stack 34.

The spacing of the arms 13,14,15 and 16 around the stack ensures that any waste which is cut away from the stack will fall between. Moreover, because the top of the stack is cut in a castellated fashion, the position of the cradle does not change during the first cutting operation.

Once the embrasures 35 and 36 are cut in the stack 34, hooks 37 and 38 (only two are shown in Fig. 3) capable of supporting the craldle 1 2 are connected between each arm 13, 14, 15 and 16 and the bottom of a respective one of the embrasures. At this stage, however, there is no loading on the hooks 37 and 38. Then using the two way ratchet arrangements 26, 27, 28 and 29, the cradle 1 2 is lowered until the load is transferred from the ropes to the hooks. At this stage the ropes can be dropped down of the cops 39, 40 and 41 (only three are shown in Fig. 1) and the cops cut off.The apparatus may be allowed to move through 90 at this stage so that the cops correspond in position with the spaces between the arms, but more preferably care is taken to ensure that the cops fall diagonally between the arms when cut.

When the cops are removed (or before if preferable) the slack in the ropes is taken up until the load of the cradle is transferred back to them from the hooks. At this stage the cradle may be lowered down 8-10 feet below the top of the stack and the cutting process repeated.

The apparatus and method according to the first and second aspects of the present invention are especially advantageous with concrete stacks. As an indication, the rate of demolition of a concrete stack using conventional techniques is six feet per week. Using the apparatus and method according to the first and second aspects of the present invention the rate is nearer sixty feet per week. Nevertheless the present invention is not intended to be restricted to concrete structures.

It will be appreciated that whilst the present invention has been described with relation to a hydraulically operated system, this may be replaced by a pneumatically operated system.

Claims (12)

1. Apparatus for demolishing stacks and similar structures comprising a breaker, means for adjusting the position of the breaker, a cradle having a plurality of arms radiating from a central point upon which the breaker and adjusting means are mounted, first and second means for suspending the cradle within a stack connected to the end of each of said arms and means for transferring the weight of the cradle from each of the first suspension means to each of the second suspension means.

2. Apparatus according to claim 1, wherein the breaker and the means for adjusting the slew and elevation thereof are hydraulically operated.

3. Apparatus according to claim 1 or 2, wherein the breaker is mounted on a telescopic arm which is hydraulically extended and retracted.

4. Apparatus according to claim 3, wherein means are provided for automatically extending the telescopic arm during use to keep the breaker up to the surface on which it is working.

5. Apparatus according to claim 4, wherein the means for automatically extending the telescopic arm comprises a diaphragm, a one-way valve and a compressed air source, the diaphragm allowing air to be drawn through the one-way valve from the compressed air source whenever the pressure on the breaker drops below a preset level.

6. Apparatus according to any preceding claim, wherein the cradle comprises four arms.

7. Apparatus according to claim 6, wherein a hydraulically-operated jack is provided at the end of each of said arms to brace the cradle against the walls of the stack when the breaker is in use.

8. Apparatus according to claim 7, wherein each of said arms carries a gallowsshaped structure which extends in use above the top of and beyond the edge of the stack, from the upper end of which a platform structure, which circles around the outside of the stack, is suspended to catch falling debris.

9. Apparatus according to any preceding claim, wherein the first suspension means comprises a rope or cable, one end of which is adapted to be secured to the outside wall of the stack at a point below the current level of demolition, and the other end of which is connected to the said weight-transferring means which comprises means for raising and lowering the cradle relative to the rope.

10. Apparatus according to claim 9, wherein the means for raising and lowering the cradle relative to the rope comprises a two-way ratchet arrangement mounted on each of the cradle through which the rope can be passed back and forth, and locked in place.

11. Apparatus according to any preceding claim, wherein the second suspension means comprises a hook member which can be hooked over the side of the stack and connected to a respective arm of the cradle,

12. A method of demolishing a stack or a similar structure in which a breaker having adjustable slew and elevation is mounted at the centre of a plurality of arms extending from a central point to form a cradle, the cradle is suspended within the stack on first suspension means from the end of each of said arms to a point of anchorage outside the stack, embrasures are cut in the top of the stack between the said arms such that the positions of the cops correspond with the positions of the arms and with the positions of the first suspension means, second suspension means are connected between the end of each arm and the bottom of a respective embrasure, the weight of the cradle is transferred from the first suspension means to the second suspension means, the cops are cut down and the weight of the cradle is transferred from the econd suspension to the first suspension means.

1 3. A method of demolishing a stack according to claim 12, wherein the stack is demolished in such a way that portions cut therefrom fall into the stack between the arms of the cradle.