EP0191336B2 - Assembly of an impact tool and a support unit - Google Patents

Abstract

1. An arrangement comprising a carrier unit (3; 103) and an impacting unit (2; 102; 202) which is disposed inside the carrier unit, is connected thereto via resilient damping elements (31; 131; 231, 231a; 331, 331a) and contains a piston (26) adapted to make a traversing movement in a cylinder (25) in the direction of an anvil-like tool (1), characterized by the following features : - the carrier unit (3; 103) has two side cheeks (16; 116) interconnected via pins (20; 44) ; - the arrangement has pairs of shaped elements (20/29; 41/46; 52/56) ; - of each pair one shaped element (20; 41; 56) is associated with the carrier unit (3; 103; 203) and one shaped element (29; 46; 52) is associated with the impacting unit (2; 102; 202) ; - the shaped elements have a section having a central axis lying in a plane aligned perpendicularly to the axis of the impacting unit (2) ; - the shaped elements are in the case of all forces occurring between the impacting unit (2) and the carrier unit (3) maintained at a distance in the direction of the axis of the impacting unit (2) upwards and downwards and, at least in connection with a further pair of shaped elements, in directions aligned transversely of the axis of the impacting unit (2) by resilient material of damping elements (31; 131; 231, 231a; 331, 331a), such damping elements being positively or non-positively connected to the shaped elements.

Description

The invention relates to an arrangement consisting of a carrier unit and a striking unit arranged within it, which is connected to the carrier unit via elastic damping elements which are effective in the direction of its axis upwards and transversely thereto and which contains a piston which can be moved in a cylinder in a translatory manner on an anvil-like tool .

In such arrangements, the carrier unit is generally screwed to a connecting piece which is pivotally attached to the boom of a mobile carrier device.

In a known arrangement, a hydraulic hammer is supported as an impact unit axially against a box-shaped support unit via compression springs. In addition, an elastic stop is provided to limit the hammer with little impact. For the rest, however, the hammer is guided in wear plates arranged on the carrier unit, so that the vibrations generated by the impact can be radiated unhindered via the housing or the carrier unit, which leads to a considerable acoustic pollution of the environment.

Furthermore, from DE-U-8 331 703 an arrangement is known in which the hammer is supported in the axial direction via an elastic insulating block against the cylindrical, closed housing of the carrier unit in such a way that the chisel tip is axially loaded. The hammer is supported radially against the housing via a pre-stressed hollow cylindrical insulation element. In the axially unloaded state, the hammer lies with a shoulder on metallic locking elements which are attached directly to the housing, so that in this case there is an undamped metallic connection between the hammer and the housing. Even if radial forces between the hammer and the housing that occur during trenching exceed the linearity range of the elastic material of the hollow cylindrical insulating element, undamped metallic bridging between the hammer and the housing, which causes noise, is produced via metallic ring elements.

Finally, an arrangement is known in which the hammer is connected to the box-shaped housing of the carrier unit via lateral rubber elements, as a result of which a damped relative movement between the hammer and the housing is possible in the axial direction. The rubber elements are stressed in the direction of the greatest stress due to shear - a type that is particularly unfavorable for soft-elastic materials. In addition, radial forces are transmitted directly between the hammer and the housing, so that there is no effective reduction in noise, at least in the event of radial force.

In addition to the noise emission, there is another disadvantage that, in the case of a tensioned operation with radial loading, the particular occurs when digging works, radial impulses are reflected from the chisel tip into the hammer, which in turn cause mass forces that are greater and more disruptive the greater the mass. With a direct metallic connection between hammer, carrier unit and carrier device, there is a very large mass, so that there is also a correspondingly large destructive effect on the chisel, hammer, carrier unit and carrier device.

With the prospectus 8301 " HYDRAULIC HAMMER " (INSTRUCTIONS MANUAL; H-Series) from NPK (Nippon Pneumatic MFG.CO., LTD.) An arrangement has been disclosed in which the hydraulic impact unit is supported laterally on a carrier unit, which - apart from a head plate - has two side cheeks and an end plate connected to this. The striking unit is fastened on the one hand elastically to the side cheeks by means of rubber cushions and, on the other hand, is supported on the end plate by means of plastic spacers.
The two side cheeks are also fastened to one another by means of transversely positioned bolts which, as seen from the end plate in the direction of the striking unit, are arranged behind the latter.

The invention has for its object to provide an arrangement with a striking unit and a carrier unit, in which even in extreme, i.e. the greatest forces occurring with such an arrangement, in particular also radial forces and when the impact unit is looked up without load, effective noise reduction and careful operation is possible.

This object is achieved by the features characterized in claim 1. By connecting the side walls only with bolts, the end walls that are otherwise customary with support units can be dispensed with. However, this significantly reduces the wall area, which also reduces sound radiation. In addition, the carrier unit has a significantly lower weight and is easy to manufacture and assemble. Accessibility to the impact unit has also been significantly improved. Due to the form elements aligned transversely to the axis of the impact unit, the elastic material of the damping elements arranged between them is only subjected to pressure in the main direction of stress both upwards and downwards, i.e. a type of load that is favorable for elastic material, resulting in a long service life for the damping elements. The elastic material is only subjected to tensile and shear stresses transversely to the hammer axis in the area of lower loads. Since there is no mechanical or metallic limitation of the relative movement in the arrangement after the linearity range of the damping material has been exceeded, if the arrangement is properly dimensioned, metallic contact between the hammer and the carrier unit as the cause of disturbing noise and high wear is reliably avoided. In the arrangement of the damping elements according to the invention, the hammer is reliably guided within the carrier unit even when the damping elements are installed without pretensioning.

The purely elastic support between hammer and carrier unit results in a longer service life for both the carrier unit and the striking unit and its tools.

For the damping elements arranged between the shaped elements, there is a pure compressive stress at all - including radial - forces in the main or longitudinal center plane of the arrangement.

Appropriate developments of the subject matter of the invention are described in the subclaims.
With the design of the arrangement according to claim 2, the number of bolts holding the side cheeks of the carrier unit together can be reduced to a minimum.
A further progression of the already disproportionate spring characteristic of the damping material can be achieved if the arrangement is designed according to one of claims 3 to 5; with the use of an adhesive connection according to claim 4, a particularly simple measure can be carried out. With the increase in the progression of the spring characteristic, it is at the same time achieved that a metallic contact between the striking unit and the carrier unit is avoided with greater certainty, while the dimensions are otherwise the same.
Additional sound absorbing measures are described in claims 6 and 7.

Fig. 1

ein Trägerfahrzeug mit einer daran befestigten Anordnung aus einem Hydraulikhammer und einer Trägereinheit in einer Seitenansicht,

Fig. 2

die aus dem Hydraulikhammer und der Trägereinheit bestehende Anordnung in einer vergrößerten Darstellung und

Fig. 3

die Anordnung nach Fig. 2 in einem Querschnitt längs der Linie III-III.

Embodiments of the subject of the invention are shown in the drawing and are explained in more detail below.
Show it:

Fig. 1

a carrier vehicle with an attached arrangement of a hydraulic hammer and a carrier unit in a side view,

Fig. 2

the arrangement consisting of the hydraulic hammer and the carrier unit in an enlarged view and

Fig. 3

the arrangement of FIG. 2 in a cross section along the line III-III.

In the exemplary embodiment according to FIG. 1, a hydraulic hammer 2 provided with a chisel 1 is arranged in a guide or carrier unit 3. The carrier unit 3 is in turn fastened to a connecting piece 4 which is fastened to a boom 5 of a carrier vehicle 6. The boom 5 has a main arm 7 which is articulated on a main carrier 8. The main carrier 8 is articulated in the carrier vehicle 6 and its angular position can be changed by a hydraulic cylinder 9. The angular position of the main arm can be changed by a hydraulic cylinder 10. An extension arm 11 is articulated to the free end of the main arm 7, the angular position of which can be changed with respect to the main arm by a hydraulic cylinder 12. Finally, the connector 4 can be adjusted in its angular position relative to the extension arm 11 by a further hydraulic cylinder 13. The chisel 1 can thus be attached to the material 14 to be reduced in wide areas at different heights, widths and angular positions by the described boom elements in the plane of the drawing, which at the same time represents the central plane of the boom 5.

In the embodiment of the arrangement consisting of the carrier unit 3 and the hammer 2 according to FIGS. 2 and 3, the guide or carrier unit 3 has two side cheeks 16, which are each screwed to the connecting piece 4 via a flange 17. The side walls 16 have bushes 18 with coaxial bores 19 in pairs at three points, in each of which there is a common bolt 20 which is axially fixed in the carrier unit 3 at each end with a roll pin 21.

While the arrangement in FIG. 2 is shown in the same view as the arrangement in FIG. 1 attached to the carrier vehicle 6, the arrangement in FIG. 3 is shown in a section along the line III-III in FIG. 2. While the center line 23 shown in broken lines in FIG. 3 represents the main or longitudinal center plane of the arrangement, the center line 24 shown in broken lines in FIG. 2 corresponds to the transverse center plane.

The hammer 2, in which a percussion piston 26 movable in a cylinder 25 indicated by dashed lines in FIG. 2 acts pulsatingly on the chisel 1, has three through openings or holes 27, the arrangement or hole pattern of which corresponds to that of the bores 19 in covers the cheeks 16. The through holes 27 have in the middle a cylindrical extension 29 delimited by collar-like shoulders 28 and the outside each has a chamfer 30. The space between the cylindrical extension 29 of the respective opening 27 and the associated bolt 20 of the carrier unit 3 is filled by a damping element 31 made of flexible material. Overall, the arrangement has three elastic connections formed in this way between the carrier unit 3 and the hammer 2.

When assembling the arrangement, the bolts 20 with the damping elements 31 are pressed through the chamfers 30 into the bores 27 until the material of the damping elements 31 completely fills the cylindrical extension 29.

In the arrangement described, the essential forces occurring in the main median plane 23 between the hammer 2 and the carrier unit 3 can be transmitted correctly both with a vertical or - with respect to the chisel 1 and the cylinder 25 - axial component as well as with a horizontal or radial component become. The elastic material has a progressive spring characteristic, which means that the transmitted force increases disproportionately compared to the deflection or the relative movement between the hammer 2 and the carrier unit 3, so that a change in the area of large forces only results in a slight change in the relative movement Has. The - in relation to the bolts 20 - radial distance of the metallic parts between the hammer 2 and the bushes 18 of the carrier unit 3 is selected in such a way that metallic contact is reliably prevented even with the greatest forces to be expected. The axial distance between the hammer 2 and the bushes 18, which in turn is related to the bolts 20, is also chosen to be so large that metallic contact does not take place even with the greatest forces to be expected with a component perpendicular to the main central plane 23.

Between the side walls 16 of the carrier unit 3, a band-shaped jacket 32 made of sound-absorbing material is arranged. The jacket 32, which has openings 33, 34 for the passage of the hoses 35 for the hydraulic medium or for the passage for the chisel 1, is held by flanges 36 of the side walls 16 and is guided to the underside of the hammer 2. The side walls 16 are covered with insulation mats 37 on their inside for further sound absorption.

In the simplest case, the damping elements 31 are connected to the corresponding surfaces of the through opening 27 in the hammer 2 or the surface of the bolts 20 by means of frictional or frictional engagement, while the shoulders 28 of the openings 27 and the bushes 18 only have a partial positive fit on the sides to the damping elements 31. The essentially hollow cylindrical damping elements 31 can, however, also be connected to the bolt 20 on their inner surface by an adhesive connection, as a result of which the spring characteristic 〈〈 applied force as a function of the relative movement progresses progressively between hammer 2 and carrier unit 3 〉〉.

The damping elements 31 and the insulating jacket 32 consist of rubber or a rubber-like material. The insulation mats 37 can consist of a thermoplastic, flexible, plastic mixture enriched with specifically heavy fillers and having a density of the order of (2 ... 2.5) 10³ kg / m³.

Claims (7)

1. Arrangement comprising a carrier unit (3) and an impacting unit (2), which is disposed inside it, is connected to said carrier unit via resilient damping elements (31) acting in the direction of its axis upwards and transversely to said axis, and contains a piston (26) able to make a traversing movement in a cylinder (25) in the direction of an anvil-like tool (1), characterised by the following features:

   - the carrier unit (3) has two side cheeks (16) interconnected only via pins (20);

   - the pins (20) at the same time respectively constitute one of the at least partially cylindrical shaped elements of several pairs of shaped elements (20, 27), the respective second shaped element (27) of which being constructed hollow and cylindrical and as a component of the impacting unit (2);

   - the pin (20) and the second shaped element (27) of each pair of shaped elements (20, 27) have a central axis lying in a plane aligned perpendicular to the axis of the impacting unit (2);

   - in the case of all forces occurring during operation of the arrangement between the impacting unit (2) and the carrier unit (3), the pin (20) and the second shaped element (27) of each pair of shaped elements (20, 27) are also maintained at a distance in the direction of the axis of the impacting unit (2) downwards by the damping element (31) attached positively or non-positively to the pair of shaped elements (20, 27).
2. Arrangement according to Claim 1, characterised in that the carrier unit (3) has only two pairs of shaped elements (20, 27), the second shaped element (27) of which is constructed in the casing of the impacting unit (2).
3. Arrangement according to at least one of the preceding claims, characterised in that the damping elements (31) are connected at least to one of the shaped elements (20, 27) of each pair of shaped elements by vulcanisation.
4. Arrangement according to at least one of Claims 1 and 2, characterised in that the damping elements (31) are connected to at least one of the shaped elements (20, 27) of each pair of shaped elements by a glued connection.
5. Arrangement according to at least one of Claims 1 and 2, characterised in that on at least one surface provided for contact with the shaped elements (20, 27) of each pair of shaped elements, the damping elements (31) have a steel sleeve (49) attached thereto.
6. Arrangement according to at least one of Claims 1 and 2, characterised in that the impacting unit (2) is enclosed by a jacket (32) of sound insulating material over the entire distance of the side cheeks (16).
7. Arrangement according to at least one of Claims 1 and 2, characterised in that the side cheeks (16) are covered on the inside and/or outside with a sound insulating material.

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