Tool driving or impacting – Convertible
Reexamination Certificate
1999-09-09
2001-10-09
Smith, Scott A. (Department: 3721)
Tool driving or impacting
Convertible
C173S049000, C173S090000, C173S128000, C173S131000
Reexamination Certificate
active
06298923
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a percussion apparatus according to the preamble of patent claim
1
. The invention relates in particular to a percussion apparatus which can be used in an impact hammer and/or drill hammer.
When work is done using impact and drill hammers, the situation often arises where the tool, e.g. a cutter or a bit, wedges or jams in the rock. While a practiced operator can usually still prevent the tool from jamming during drilling with the drill hammer, it is not always possible, during demolition work using a large impact hammer, even for the expert to avoid wedging or jamming of the cutter. It is usually difficult to release a wedged tool because this can only be accomplished by using a second cutter, in the case of a certain hammer design only by using a second hammer, to release the jammed tool by impact. During the impact-release of a jammed bit, the effort necessary for this purpose is usually particularly high since the drill is already lodged deep in the rock and it is thus necessary to cut away all the rock around the drill hole. In any case, the impact-release of a jammed tool requires considerable outlay in terms of time and equipment.
2. Description of the Related Art
U.S. Pat. No. 5,485,887 discloses a percussion apparatus having an impact-generating device which has an axially reciprocating percussion piston. In an operating state, a tool can be forced in an operational-impact direction by the percussion piston while, in an impact-release state, a blow of the percussion piston can be transmitted to the tool such that said tool can be forced in an impact-release direction, which is counter to the operational-impact direction. The reversal of the impact direction is achieved purely pneumatically by the displacement of an outer piston, which encloses the percussion piston.
OBJECTS AND SUMMARY OF THE INVENTION
The object of the invention is to specify a percussion apparatus by means of which the impact-release of a jammed tool can be carried out in a straightforward and time-saving manner.
The object is achieved according to the invention by a percussion apparatus having the features of patent claim
1
. Advantageous further developments of the invention are defined in the subclaims. Such a percussion apparatus can be used particularly advantageously in an impact hammer and/or drill hammer.
The invention relates to a percussion apparatus having an impact-generating device which has an axially reciprocating percussion piston, it being possible, in an operating state, for a tool to be forced in an operational-impact direction by the percussion piston, wherein, in an impact-release state, a blow of the percussion piston can be transmitted to the tool via an impact-converting device such that said tool can be forced in an impact-release direction, which is counter to the operational-impact direction.
The invention thus provides a percussion apparatus in which the impact energy of the percussion piston, which belongs to the impact-generating device, can be utilized for releasing the jammed tool from the rock again by impact, in that said tool is forced in a direction which is directed counter to the normal impact direction. The percussion piston usually strikes against the tool, in the operational-impact direction, directly or via an interposed riveting set. The impact-converting device makes it possible to pick up the movement of the percussion piston either in the operational-impact direction or in the impact-release direction and supply it to the tool in the form of a blow in the impact-release direction.
Particularly advantageous is an embodiment of the invention in which the blow is transmitted, and has its direction deflected, via the impact-converting device when the percussion piston forces the impact-converting device in the operational-impact direction. The percussion piston is usually designed such that it can absorb the greatest loading in the operational-impact direction, because it strikes against the tool during movement in this direction. This means that it can also withstand the loading necessary for the impact-release since, in this case, the forces and blows which are necessary tend to be smaller than in the operating state. For the further development of the percussion apparatus according to the invention, it is not necessary for a conventional percussion apparatus to be newly designed in terms of impact geometry and strength. Rather, the solution according to the invention can be achieved by the impact-converting device being added.
A particularly advantageous further development of the invention is defined in that the impact-converting device has an impact-deflecting device and an impact-transmission device; the impact-deflecting device has a deflecting lever which can be pivoted about a rotary pin, can be forced in the operational-impact direction at a first lever end by the percussion piston and is coupled to the impact-transmission device at a second lever end, which is located opposite in relation to the rotary pin and, accordingly, can be moved in the impact-release direction; and the impact-transmission device has a slide which can be moved in the impact-release direction as well as a tool locking mechanism which is fastened on the slide and transmits the blow to the tool.
The impact-deflecting device serves for picking up the blow which is delivered by the percussion piston and directed in the operational-impact direction and for deflecting said blow into a blow which is directed in the opposite, impact-release direction. The deflected blow is transmitted to the tool by the impact-transmission device, and the tool can then be released by impact.
The percussion piston moving in the operational-impact direction can advantageously act directly on the deflecting lever, which belongs to the impact-deflecting device.
Alternatively to this, the impact-deflecting device has, between the percussion piston and the deflecting lever, a sliding lever which can be displaced between an operating position and an impact-release position, can be pivoted about one of its ends and via which the percussion-piston blow in the operational-impact direction can be transmitted to the deflecting lever. On the one hand, the sliding lever permits the blow to be transmitted from the percussion piston to the deflecting lever with a geometry which is particularly advantageous in terms of the force transmission. In addition, the sliding lever can be displaced between the operating position and the impact-release position and thus serves as a changeover means between the operating state and the impact-release state, which the operator can select freely by adjusting the sliding lever.
In a preferred embodiment of the invention, the impact-generating device has a percussion mechanism with a pneumatic spring acting on one side. Said percussion mechanism, which is known per se, has the advantage of being very robust and straightforward to construct and has proven to be very successful in practice. Without any change in the design of the percussion mechanism being necessary, the percussion apparatus can be supplemented in the manner according to the invention by virtue of the abovedescribed features being added.
In another embodiment of the invention, the blow is transmitted via the impact-converting device when the percussion piston forces the impact-converting device in the impact-release direction. In this case, the percussion piston—in contrast to the embodiments described above—is already moving in the direction in which the tool is to be released by impact. This has the advantage that there is no need for any impact-deflecting device.
Rather, a particularly advantageous embodiment is defined in that the impact-converting device has an impact-transmission device; the impact-transmission device can be forced in the impact-release direction by the percussion piston and transmits the blow to a point which is located at the tool-receiving means; and fastened on the impact-transmission device is a tool locking
Lysek Mirko
Schmid Wolfgang
Boyle Fredrickson Newholm Stein & Gratz S.C.
Smith Scott A.
Wacker-Werke GmbH & Co. KG
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