Cutlery – Cutting tools – Saw
Reexamination Certificate
2001-12-06
2004-03-09
Shoap, Allan N. (Department: 3724)
Cutlery
Cutting tools
Saw
C083S698410, C411S349000
Reexamination Certificate
active
06701629
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention is based on a machine tool receptacle.
From European Patent Disclosure EP 0 904 896 A2, a grinding machine tool receptacle for a hand-held angle grinding machine is also known. The angle grinding machine has a drive shaft that has a thread on the side toward the tool.
The grinding machine tool receptacle has a slaving means and a lock nut. For mounting a grinding wheel, the slaving means is slipped with a mounting opening onto a collar of the drive shaft and braced against a bearing face of the drive shaft in the circumferential direction by nonpositive engagement via the lock nut. The slaving means has a collar, extending axially on the side toward the tool, that on two radially opposed sides on its outer circumference has recesses that extend axially as far as a bottom of the collar. From each of the recesses, a respective groove extends on the outer circumference of the collar, counter to a driving direction of the drive shaft. The grooves are closed counter to the driving direction of the drive shaft and taper axially, beginning at the recesses, counter to the drive direction of the drive shaft.
The grinding wheel has a tool hub with a mounting opening, in which two opposed tongues are disposed, pointing radially inward. The tongues can be introduced axially into the recesses and then in the circumferential direction, counter to the driving direction, into the grooves. The grinding wheel is fixed by positive engagement in the grooves in the axial direction via the tongues and by nonpositive engagement by means of the tapering contour of the grooves. During operation, the nonpositive engagement increases as a consequence of reaction forces exerted on the grinding wheel, which act counter to the driving direction.
To prevent the grinding wheel from running off center when the drive shaft is braked by the slaving means, a stopper, which is movably supported in the axial direction in an opening, is disposed in the region of a recess on the circumference of the collar. In a working position where the grinding wheel points downward, the stopper is deflected axially by gravity in the direction of the grinding wheel and closes the groove in the direction of the recess and blocks a motion of the tongue, located in the groove, in the driving direction of the drive shaft.
SUMMARY OF THE INVENTION
The invention is based on a machine tool receptacle, having a slaving device by way of which an insert tool can be operatively connected to a drive shaft; wherein the insert tool is operatively connectable to the slaving device via at least one detent element, supported movably counter to a spring element, which detent element snaps into place in an operating position of the insert tool and fixes the insert tool by positive engagement.
It is proposed that the insert tool is a circular saw blade. By means of the positive engagement, a high degree of safety can be attained, and a simple, economical, tool-less fast-clamping system for a circular saw, especially a circular power saw can be created. The circular saw blade can be securely prevented from running off center, even in the event of braked drive shafts, in which major braking moments can occur.
Because of the movably supported detent element, major deflection of the detent element can be made possible in the assembly of the circular saw blade, and as a result on the one hand a major overlap between two corresponding detent elements, and an especially secure positive engagement, can be realized, and on the other, a readily audible snap-in noise can be achieved, which advantageously tells the user that the snap-in operation has been completed as desired and that the tool is ready for operation.
The detent element can fix the circular saw blade by positive engagement directly or indirectly via an additional component, for instance via a rotatably and/or axially displaceably supported detent lever or tappet and the like coupled to the detent element. The detent element can fix the circular saw blade by positive engagement directly and/or indirectly in various directions, such as the radial direction, axial direction, and/or especially advantageously the circumferential direction. It is also possible that by the positive-engagement fixation of the circular saw blade to the detent element in a first direction, such as the radial direction, the circular saw blade is fixed by positive engagement in a second direction, for instance the circumferential direction, by means of a component separate from the detent element.
The movably supported detent element can be embodied in various forms that appear useful to one skilled in the art, for instance in the form of an opening, protrusion, peg, bolt, and so forth, and can be disposed on the circular saw blade or on the slaving device. The detent element can itself be supported movably in a component at a bearing point, for instance in a flange of the slaving device or in a tool hub of the circular saw blade. Moreover, by means of the positive engagement, an advantageous coding can be attained, so that only intended circular saw blades can be fastened in the machine tool receptacle. The slaving device can be embodied at least in part as a separable adapter part, or it can be joined inseparably to the drive shaft by nonpositive engagement, positive engagement, and/or material engagement.
The detent element can be embodied as movable in various directions counter to a spring element, for instance in the circumferential direction or especially advantageously in the axial direction, as a result of which a structurally simple embodiment is attainable.
In a further feature of the invention, it is proposed that a drive moment can be transmitted via a positive-engagement connection between the circular saw blade and the slaving device. A high drive moment can be securely transmitted, and moreover, a drive moment can be prevented from acting on a nonpositive connection.
If the detent element can be released from its detent position by an unlocking button, then independent separation of the detent connection, for instance by a braking moment, can be securely avoided, and safety can thus be enhanced. Operation of the circular saw blade in two circumferential directions can be made fundamentally possible, and the convenience upon mounting and unmounting of the circular saw blade can be increased.
It is also proposed that the circular saw blade is connectable to the slaving device via a tongue-and-groove connection, which is secured by positive engagement via at least one detent element in an operating position of the circular saw blade. With a tongue-and-groove connection, an especially space-saving, lightweight construction can be attained, in which individual components are used for multiple functions; for instance, the detent element and/or spring elements that engage grooves can be used for radial centering, fixation in the axial direction, and/or fixation in the circumferential direction.
If the circular saw blade is connected to the slaving device in the circumferential direction via at least a first element and in the axial direction via at least a second element, however, then simple and economical tool hubs can be attained, which can advantageously be embodied as flat. The tool hubs can be prevented from catching in production and storage, and good manipulation of the circular saw blade with its tool hubs can be made possible. The components can furthermore be designed advantageously for their function, that is, for either the fixation in the circumferential direction or the fixation in the axial direction. The elements can be formed by a single component or advantageously by separate components. The tool hubs can advantageously be embodied simply, with a closed centering bore, and low-vibration running of the circular saw blade can be made possible. Also, given a suitable choice of the diameter of the centering bore, it can be attained that circular saw blades intended for the machine tool receptacle of the invention can be secured to conventional circular saw b
Heckmann Markus
Krondorfer Harald
Schadow Joachim
Prone Jason
Robert & Bosch GmbH
Shoap Allan N.
Striker Michael J.
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