Abrading – Frame or mount – For hanging rigid – rotary abrading tool
Reexamination Certificate
2001-11-02
2004-09-28
Hail, III, Joseph J. (Department: 3723)
Abrading
Frame or mount
For hanging rigid, rotary abrading tool
C451S353000, C451S359000, C451S360000, C451S508000, C451S509000, C451S510000, C451S511000, C451S512000
Reexamination Certificate
active
06796888
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a receptacle for securing a tool to a drive shaft of a power tool, a receiving opening being arranged on the tool or on the drive shaft, and a center axis of the drive shaft extending therethrough, the opening co-acting with a suitably formed securing section arranged in a raised fashion at the other one of the two elements, in order to form a positive engagement for transmitting a torque between the drive shaft and the tool.
The invention further relates to a suitable adapter that can be used, if the receiving opening and the securing section of the tool or of the drive shaft are not mated with each other.
A receptacle of the type mentioned at the outset is known from U.S. Pat. No. 4,980,976 which discloses a U-shaped angled cutting knife for severing adhesive beads in window panes of motor vehicles, the cutting knife having a star-shaped receiving opening in the shape of a regular polygon for securing an oscillatingly driveable drive shaft, the receiving opening being attachable to a suitably shaped securing section of the drive shaft. For securing the cutting knife after attaching to the securing section of the drive shaft with its receiving opening, a screw connection is provided, e.g. in form of a nut that can be screwed onto a screw neck of the drive shaft.
Such a receptacle for securing the tool to the drive shaft is provided in particular for oscillatingly driveable tools, in which a positive fit engagement between the drive shaft and the tool for the transmission of higher torques is required.
To this end, a plurality of tools are used, which cannot only be used as cutting knives, but also for other tasks, e.g. for sawing. By means of such oscillatingly driven saw blades, for example, precise cuts in car body working can be performed. For sawing in hard accessible locations, also finger-like tools are used, for instance in order to be able to perform special cuts in wood constructional work. Another field of application is grinding, as e.g. described in U.S. Pat. No. 4,920,702, or scraping.
It has turned out to be disadvantageous that the known receptacle for engagement between the tool and the drive shaft, in particular for such oscillatingly driven tools, tends to wear out after longer operation under high load.
SUMMARY OF THE INVENTION
It is a first object of the invention, to create an improved power tool having an improved receptacle for engagement between the drive shaft and the tool.
It is a second object of the invention, to create an improved receptacle in which the danger of wear out of the receiving opening is reduced and a transmission of high torques is guaranteed also in long-term operation.
It is a third object of the invention, to provide an improved power tool having a receptacle for a tool that is particularly suited for the transmission of high torque even when oscillatinly driven back and forth about a longitudinal axis.
It is a further object of the invention to provide a tool having an improved receptacle in which the danger of wear out of the receiving opening is reduced and a transmission of high torques is guaranteed also in long-term operation.
It is another object of the invention to provide a tool having an improved receptacle for securing to a power tool allowing the transmission of high torque even when oscillatinly driven back and forth about a longitudinal axis.
It is a further object of the invention to provide an adapter that can be used for the engagement between the tool and the drive shaft, if the shapes of the receiving opening and the securing section on the tool and on the drive shaft are not mated with each other.
These and other objects are achieved according to the invention by a receptacle with a receiving opening the shape of which is mated to a securing section of the drive shaft of the power tool, the securing section and the receiving opening having a plurality of bulges arranged at a radial distance from the longitudinal axis of the drive shaft, the bulges being, preferably, continuously connected by lateral flanks forming recesses between the bulges. The bulges may, preferably, be configured as rounded tips.
The object of the invention is in that way completely achieved.
By means of the new shape, namely, the occurrence of high torques and/or high surface pressures on any sharp edges like a regular polygon, used in prior art devices, is avoided. Instead, the torque is now mainly transmitted to the tool by lateral flanks forming recesses between the bulges.
By means of such a shape, lumped loads and, thus, high surface pressures are avoided, which occurred up to now in receiving openings in the form of regular polygons.
In that way, a reliable engagement between the tool and the drive shaft is created, by means of which extraordinarily high torques can be transmitted even with oscillating drives or with impact loads, without any danger that the receiving-opening or of the securing section may wear out.
In a preferred embodiment of the invention, the receiving opening has at least three, preferably six rounded tips pointing outwardly, with two adjacent tips being connected by a curved section, which extends to the center axis. Each pair of adjacent tips may be connected by lateral flanks extending from the pair of tips toward the longitudinal axis and converging in a common apex.
By means of such an embodiment, a particularly constant torque transmission is reached, which avoids high surface pressures.
In an additional improvement of the invention, the curved sections are configured in an arch-shaped, preferably in a circular arc-shaped manner.
According to another embodiment of the invention, the diameter ratio between a first diameter, determined by a circle on which the tips are arranged, and between a second diameter, determined by a circle on which the apexes are arranged, is approximately 4 to 6, preferably approximately 4.5 to 5.5, in particular approximately 5.1.
In another embodiment of the invention, the ratio between the first diameter ratio that is determined by the distance between two tips being opposite to each other and a radius of the arc-shaped rounded tips is approximately 30 to 46, preferably approximately 34 to 42, in particular approximately 37.
By means of these features, a particularly favorable torque transmission between the drive shaft and the tool can be guaranteed, without any danger of wearing out under oscillating load or impact load.
Preferably, the receiving opening is arranged on the tool and the securing section is arranged on the drive shaft.
In that way, a simple manufacture can be reached particularly by punching the receiving opening out of the tool.
According to another embodiment of the invention, the receptacle comprises a securing screw, which can be screwed into a threaded blind hole of the drive shaft.
In this way, the securing screw has preferably a head, which is dimensioned for being positioned onto the tool.
In an additional improvement of the invention, a clamping flange is provided, which has a central opening for receiving the securing screw and which has an annular protrusion on its side facing the drive shaft, the annular protrusion being dimensioned for positioning onto the tool.
By means of this measure, a good pressure for securing can be reached.
In an additional improvement of this embodiment, the clamping flange has a recess on its side facing the drive shaft, the recess being mated in its form and size with the securing section of the drive shaft.
In a further embodiment of the invention, the clamping flange is secured rotatably to the securing screw.
In that way, the handling is facilitated.
If the securing section is provided at the drive shaft of the power tool, the drive shaft has preferably a retaining flange at its tool side, the securing section being arranged at the side of the retaining flange facing the tool.
In that way, the tool can be screwed to the drive shaft, with the retaining flange serving as a supporting surface.
The object of the invention is further achieved by an adapter for clamping a
C. & E. Fein GmbH & Co. KG
Hail III Joseph J.
McDonald Shantese
St. Onge Steward Johnston & Reens LLP
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