Boring or penetrating the earth – Bit or bit element – Impact or percussion type
Patent
1994-10-05
1995-08-29
Buiz, Michael Powell
Boring or penetrating the earth
Bit or bit element
Impact or percussion type
173100, 175296, E21B 1000
Patent
active
054452325
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a hydraulic breaking hammer comprising a machine housing in which a percussion motor includes a cylindrical part and a percussion or impact piston which moves reciprocatingly in the cylinder part and strikes against a breaking tool which is supported in a tool carrying portion at the front of the machine housing, said machine housing being supported inwardly of a surrounding carrier support device which is attached to connecting means which functions to bring the hammer mechanically into alignment during its work.
Breaking hammers of the type concerned are normally fitted to hydraulically operated excavating machines, or diggers, of different sizes, the hydraulic systems of which are switched so as to also drive the hammer, said hammer being connected to the outer end of the jib or boom of the digger through the medium of connecting devices, and said boom functioning to guide the hammer during a working operation.
The machine housing of the breaking hammer is typically comprised of separate cylinder parts, which surround the percussion piston, the seals and the valve system, and are grouped axially adjacent one another within the carrier support and held tightly together by strong side bolts, with the intention of obtaining a reliable seal between the cylinder parts against the high internal hydraulic working pressures that occur. The carrier support is normally comprised of metal plates held together by transverse bolts, or of casings between or in which the side-bolted cylinder parts are secured in some suitable fashion. The breaking hammer obtains a complicated machine housing construction in both instances, although the carrier support is required as a necessary outer protective means, since the hammer is handled harshly and may be subjected to repeated impacts against the work object. Examples of machine housings of the aforesaid configurations are described in U.S. Pat. Nos. 3,866,690 and 4,552,227.
The complicated breaking hammer construction has a negative influence on machine safety. Wear and corrosion together with micro-movements in the joints as a result of impacts and vibrations occurring as the hammer is used results in gradual penetration of working oil into the joints and their seals, which can result in oil leakages with subsequent danger to the surroundings and also in the risk of damage to the machine. The side bolts are also liable to fracture, with serious consequences.
In recent times, endeavours have been made to enhance machine safety by obviating the use of side bolts in sledge-mounted hydraulic drilling machines. U.S. Pat. No. 4,482,079 teaches an example of this concept. The considerably heavier work involving powerful functional and external impact stresses normally associated with hydraulic breaking hammers, for instance in concrete breaking, stone crushing and rock bursting operations in which machine and carrier weight together may reach to 3-9 tonnes, demands a mechanical strength which hitherto has been impossible to achieve conventionally with a breaking hammer and carrier support of acceptable handling weight with a starting point from the technology of drilling machines.
The object of the present invention is to transform the entire machine housing of a hydraulic breaking hammer of the type concerned to a simplified unit which is constructed integrally with its carrier support in a manner to combine a reasonable handling weight of the hammer with an impact durability which gives enhanced protection to the percussion motor and pressure oil channels of the hammer. At the same time, the integrally constructed machine housing provides improved sound damping around the jointless percussion motor of the machine housing in the interior of the carrier support. Another object is to enhance machine safety through the medium of said combination, by reduced risk of leakage since side bolts are no longer required, and by decreasing the separate elements included in the hammer, this latter also being advantageous with regard to maintenance, exchange of
REFERENCES:
patent: 4921056 (1990-05-01), Ennis
patent: 4932483 (1990-06-01), Rear
Brannstrom Osten
Henriksson Roland
Atlas Copco Berema Aktiebolag
Buiz Michael Powell
Stone Mark P.
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