Tool driving or impacting – Impacting devices – With means for rotating tool
Patent
1993-02-26
1994-11-22
Rada, Rinaldi I.
Tool driving or impacting
Impacting devices
With means for rotating tool
173 48, 173204, 173205, B23B 4516
Patent
active
053660250
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a drill hammer and/or a percussion hammer.
In particular, it relates to such a hammer which has a striking mechanism with a striker accelerated by a driver member and striking a shaft of a tool, wherein the driver member is tiltable around an axis and reciprocatingly driven by a drive element rotated by a motor.
Such a device is already known from EP 0 145 070 B1. In this device the striker is driven in a reciprocating manner by a leaf spring cooperating with a supporting part. This construction is relatively costly and capable of improvement with respect to efficiency.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a drill and/or a percussion hammer, which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a drill and/or percussion hammer in which the driver member is driven in a reciprocating motion and is formed as a one-piece member and so as to be resilient in a springing manner and is articulated at the striker with play in an axial direction.
When the drill and/or percussion hammer is designed in accordance with the present invention, it has the advantage over the prior art that its construction makes it simple and inexpensive to manufacture, that the applied energy is converted almost completely into percussive energy, and that the bearing of the driver member is extensively protected from unwanted percussive forces. Moreover, friction occurs only in one joint in the drive of the striking mechanism.
Advantageous further developments and improvements of the drill and/or percussion hammer are possible. In a particularly advantageous manner, the striker travels in free flight for a certain distance before striking the tool or intermediate anvil so that there is no mechanical coupling between the driver member and the striker at the moment of impact. This prevents reaction forces on the driver member and its support during the impact of the striker. It is particularly simple and inexpensive to integrate an eyelet or axle directly in the driver member for the rotational articulation of the driver member. A lever which is formed so as to be integral with the driver member for transmitting the oscillating movement of the cam path to the driver member serves the same purpose. The driver member can be advantageously constructed in different ways, e.g. as a punched part, and the width of the spring material can be adapted at every location to the occurring forces. In addition, the driver member can be constructed as a bent round-wire spring. This can be easily bent to form an eyelet for the support of the driver member. Further, the driver member can be constructed as a plastic injection molded part, particularly of polyoxymethylene. This has the advantage that all cross sections of the spring can be designed in conformity to exacting requirements. A cup-shaped connecting link which can be formed so as to be integral with the driver member, which is produced particularly from plastic, or an articulated sleeve in which the lever of the driver member engages can be used for the articulation at the cam path which is constructed as an eccentric. A driver member which is constructed as a one-armed spring has the particular advantage that it can withstand torsional strain and can accordingly absorb additional forces between the striker and bearing of the driver member. A more efficient use of energy is provided when the striker which is thrown back at the tool transmits its kinetic energy to the driver member during its return stroke in that this energy is converted into spring energy. The wear on parts and bearings is considerably reduced as a result of the design of the individual structural component parts of the striking mechanism, particularly the selected magnitude of play between the driver member and striker, in that the velocities of the driver member and str
REFERENCES:
patent: 4726430 (1988-02-01), Hendrikx et al.
patent: 4895212 (1990-01-01), Wache
patent: 5052497 (1991-10-01), Houben et al.
Dutschk Axel
Hecht Joachim
Rada Rinaldi I.
Robert & Bosch GmbH
Striker Michael J.
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