A crushing apparatus designed to crush a structures by opening and closing actions of arms operated by a hydraulic cylinder is already known publicly. This kind of crushing apparatus, for example, as disclosed in the unexamined Japanese patent application JP-A-63-40061, is generally equipped with crushing blades, which is provided on the respective front ends of the arms to press and crush the concrete structure by opening and closing the arms, together with shearing blades, which are respectively provided closely to a pivot point of the intermediate portions of the arms, to shear reinforced steels, frame steels and the like exposed from the steel-reinforced concrete structure when they are crushed by the crushing blades.
However, broken pieces produced by crushing a structure are too large in size to be carried out of the site easily and to be subjected to recycling. Thus, the structure once crushed must be crushed again into smaller fragments. In order to re-crush such broken pieces of once crushed structure, the crushing apparatus such as one described in the unexamined Japanese patent application JP-A-63-40061 is not suited, because such an apparatus is extremely inefficient for this purpose.
On the other hand, there are several known crushing apparatuses capable of crushing large size broken pieces into smaller pieces as disclosed in the unexamined Japanese patent application JP-A-59-187976 and JP-A-4-347270. According to these prior art apparatuses, in each of the paired arms, there are provided through holes at an intermediate portion of a front portion of the arm (i.e. a region extending from the pivot point of arms to the distal end thereof). Furthermore, one of these paired arms is provided with protrusions or rollers at its intermediate portion. Thus, the broken pieces, produced when the structure is demolished, are scooped with these paired arms. Then, these broken pieces are crushed further into smaller pieces with these paired arms closing, while allowing the smaller broken pieces to pass through the above-described through holes.
Demolition work of wooden houses or concrete structures is generally classified into the following categories:
(1) demolition of wooden or concrete columns, beams, and walls;
(2) crushing of concrete blocks produced by demolition of buildings into smaller pieces;
(3) shearing of wooden beams and columns, or reinforced steels, or frame steels;
(4) collection of broken wooden pieces of beams and columns and shared reinforced steels and frame steels produced by demolition of structure; and
(5) transportation of wooden fragments, reinforced steels, frame steels, concrete pieces and the like produced by demolition of structure onto a load-carrying platform of a truck or like vehicle.
When performing these works with various attachments selectively attached to a working machine such as a power shovel, a lot of time is required for replacing an attachment with another suitable for the next work and then a number of attachments are used, with the result that it is inefficient and uneconomical to perform such works. Meanwhile, in the case where the crushing apparatus such as the one disclosed in the previously-described unexamined Japanese patent application JP-A-63-40061 suited for the demolition of structures is used, the above described work (1) can be performed efficiently, but other works (2), (4) and (5) cannot be carried out or can be carried out with extremely poor efficiency. On the other hand, if the crushing apparatus such as the one disclosed in the previously-described unexamined Japanese patent application JP-A-59-187976 or the unexamined Japanese patent application JP-A-4-347270 which is suited for the work for crushing broken pieces into smaller pieces is used, the above classified works (2) through (5) can be performed effectively, but the most fundamental work (1) cannot be carried out effectively due to lack of adequate power.
Although there are known attachments suited for the above-describe works (3) through (5), those are not suited for the above-described works (1) and (2).