WO2002022965A1

WO2002022965A1 - Impactor control

Info

Publication number: WO2002022965A1
Application number: PCT/NZ2001/000187
Authority: WO
Inventors: Angus Peter Robson
Original assignee: Rocktec Ltd
Current assignee: Rocktec Ltd
Priority date: 2000-09-12
Filing date: 2001-09-10
Publication date: 2002-03-21
Anticipated expiration: 2003-03-12
Also published as: NZ505698A; AU2001290375A1

Abstract

The present invention relates to a method of operating an impactor characterised by the steps of assessing the properties of the surface to be impacted upon, and adjusting the amount of the impact to be delivered by the impactor in accordance with the properties of the surface.

Description

IMPACTOR CONTROL

TECHNICAL FIELD

This invention relates to impactor control.

Reference throughout the specification will be made to the present invention as being a concrete breaker, however it should be appreciated that the present invention can apply to other impactors such as post rammers, rock crushers and the like.

Reference throughout the present invention shall now be made to the concrete breaker as being portable.

Portable concrete breakers can be self propelled or attached in the front or back of vehicles such as skidsteer loaders, excavators or rubber tyred backhoes. These vehicles have advantages in that they are relatively small, powerful and manoeuvrable.

Concrete breakers may come in a variety of forms. For ease of reference throughout the present invention, the concrete breaker will be referred to as a drop hammer type which lifts up a weight and then allows it to drop onto the surface or concrete to be broken.

Generally concrete is required to be broken is in the form of slabs and beams with a relatively flat upper surface.

In most cases it is desirable to break the concrete by hitting on the surface without having the point go through into the body of the concrete.

It should be appreciated that the variety of surfaces to be broken all have different properties. For example, the surfaces may have different thicknesses or have different strengths.

However, the construction of conventional concrete breakers do not take into account these differences. While some concrete breakers may operate at variable frequencies, the actual impact provided by the concrete breaker is the same every time. This constant impact does not often provide optimal results. For example, the concrete breaker may be used to break a concrete surface which is thinner than average. Applying an average impact force to that concrete may more than just break the concrete, but may also cause considerable damage to the substrate below or cause the breaker point to follow through the indentation in the concrete such that the point hammer lodges in a hole and is difficult to extract.

Alternatively, the concrete may be thicker than average and therefore considerably more time is required to break the concrete with the weight that only delivers an average impact.

It is an object of the present invention to address the above problems, or at least provide the public with a useful choice.

Further objects and advantages of the present invention will become apparent from the following descriptions which are given below in examples.

DISCLOSURE OF INVENTION

According to one aspect of the present invention it is provided a method of operating an impactor characterised by the steps of:

a) assessing the properties of the surface to be impacted upon, and

b) adjusting the amount of impact to be delivered by the impactor in accordance with the properties of the surface.

Reference should be now made to the present invention as being a concrete breaker, however it should be appreciated that the present invention can be applied to other impactors such as rock crushers and post rammers.

Reference to the surface being impacted upon should now be made to it as being concrete, however it should be appreciated that the present invention will work well on a variety of surfaces.

What assessment is made of the properties of the surface depends upon what the operator of the impactor is trying to achieve. For example, the impactor may note the thickness of the concrete to be broken and may even have an idea of the relative existence of that surface to breakage from impact. The operator may also have an appreciation of the substrate below the surface and whether it is desired it to cause minimal disturbance to that substrate or considerable disruption. The latter is a preferred option if the present invention is to be used for the mending of pot holes.

Typical concrete breakers and other impactors drop weights from a set height onto the surface impacted on.

The applicant has found that changing the distance the weight is dropped is a simple yet effective way of changing the impact which requires minimal involvement by the operator of the impactor and minimal adaptation of existing impact.

A common type of concrete breaker uses a continuously rotating chain to lift and drop the weight. For example, the chain is a continuous belt which fits round a drive cog and a guide pulley to form an oval loop. In some embodiments, there is a latch or dog fitted to this chain. As the chain goes around, the latch catches a protrusion on the column of the fallen weight and lifts it upwards. When the latch moves with the chain around the drive cog or pulley, it unhooks or detaches from the weight causing the weight to fall again. The rate of revolution of the chain determines the frequency that the weight is lifted and dropped.

The height that the weight drops remains constant in these preset devices, thus leading to a constant amount of impact with its contingent problems.

In the present invention there is preferably provided a moveable stop which can be placed at different heights on the weight. Thus, if the stop is placed lower down on the weight, then the latch or dog on the chain would pick the weight up earlier in its revolution and lift the weight higher or a greater distance as a consequence. Conversely, if the stop is moved higher up on the weight, then the dog on the chain will only catch the weight near the end of its revolution and thus lift the weight up only a small distance.

According to another aspect of the present invention there is provide a drop hammer weight for an impactor which has apertures drilled therethrough allowing the removal and insertion of a stop. In one embodiment, the stop may pass through an aperture in a plate on the outside of the weight. Preferably the plate has a number of apertures through which the pin can pass.

The stop may in some embodiments be a bolt. The operator may unscrew the stop/bolt and move the bolt to another position, insert the bolt thereafter so it passes horizontally through the weight to extend out the other side. The extension of the bolt should be sufficient that a latch or dog on the chain can catch the bolt and lift the weight as a consequence of its upward movement. A configuration of the bolt and the dog relative to each other should also be such that the latch can readily disengage from the bolt near the top of the pulley around which the chain passes.

Thus, the positioning of the bolt creates a different height at which the weight will be lifted. The different height of course corresponds to a different amount of impact delivered by the falling weight.

In alternative embodiments of the present invention there may be provided a method of altering the height that the weight is lifted by adding more dogs or removing dogs from the chain. However, it is thought by the applicant that this would be relatively difficult to achieve and the provision of a removeable stop with respect to the weight is more practical.

According to a further aspect of the present invention there is provided an impactor configured to operate in accordance with the method as herein described.

The present invention overcomes a problem in the prior art by recognising that a variable impact can give the operator of the impactor greater choice and flexibility.

The concept disclosed herein of changing the height from which the weight is dropped is an elegant means by which the amount of impact can be changed.

Finally, use of a variable positioned stop is a simple way to implement the present invention.

BRIEF DESCRIPTION OF DRAWINGS

Aspects of the present invention will now be discussed by way of example only with reference to the accompanying figure in which: Figure 1 is a diagrammatic view of one embodiment of the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

Figure 1 is a diagrammatic view of a drop hammer mechanism in accordance with one aspect of the present invention.

While only the internal aspects of the present invention are illustrated in Figure 1, it should be appreciated that the present invention includes at least some if not all, traditional components including housing motors, vehicle attachments and so forth.

With respect to Figure 1, there is illustrated a chain drive generally indicated by arrow 1 which passes around a drive pulley (2) and a guide pulley (3).

In the embodiment shown, two latches or dogs (4) are attached to the chain (1). One is a 'real' dog and the other just shows an alternate position during the operation of the machinery.

Positioned alongside the chain is a weight or drop hammer (5). The drop hammer (5) has a number of apertures (6) drilled horizontally through it.

hi the lowest aperture (6a) is fitted a stop or bolt (7). The bolt (7) actually passes through the outside of the housing (not shown) of the impactor. ^"Not^" clearly shown, the surface under the bolt (7) is a flat surface which increases the contact area between the bolt (7) and the dog (4).

The bolt (7) extends sufficiently outwards from the weight that the dog (4) catches the pin as the chain moves in the direction shown to lift the weight (5) upwards.

It can be seen if the bolt (7) had been placed in either the upper apertures (6b) or (6c), that the weight will be lifted a lesser height than the bolt in aperture (6a).

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope of the appended claims.

Claims

CLAIMS:

1. A method of operating an impactor characterised by the steps of;

a) assessing the properties of the surface to be impacted upon, and

b) adjusting the amount of the impact to be delivered by the impactor in accordance with the properties of the surface.

2. A method as claimed in claim 1 wherein the impactor is a concrete breaker

3. A method as claimed in either claim 1 or claim 2 wherein the means by which the impact is altered is to change the height of the weight being dropped by the impactor

4. A method as claimed in any one of claims 1 to 3 which is applied to an impactor having a rotating chain to lift and drop the weight of the impactor.

5. A method as claimed in claim 4 wherein the impactor includes a weight through which there are a number of apertures through which a stop can be passed which can interact with the rotating chain.

6. A method as claimed in any one of claims 1 to 5 wherein the stop is in the form of a bolt.

7. A method as claimed in any one of claims 4 to 6 wherein the stop has a flat surface on its underside configured to catch the rotating chain.

8. A method as claimed in claim 4 characterised in the step of adding more dogs and removing dogs from the rotating chain.

9. A drop hammer weight for an impactor which has apertures drilled therethrough allowing the removal and insertion of a stop.

10. An impactor configured to operate in accordance with the method as claimed in any one of the previous claims.

11. A method substantially as herein described with reference to and as illustrated by accompanying drawings

12. A drop hammer substantially as herein described with reference to and as illustrated by the accompanying drawings

13. An impactor substantially as herein described with reference to and as illustrated by the accompanying drawings.