Measuring and testing – Specimen stress or strain – or testing by stress or strain... – By loading of specimen
Reexamination Certificate
2000-12-15
2002-09-24
Noori, Max (Department: 2855)
Measuring and testing
Specimen stress or strain, or testing by stress or strain...
By loading of specimen
C073S832000
Reexamination Certificate
active
06453751
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a device for measuring the pulling-in force to which a tool support part, such as a tool system module in the form, for example, of a basic tool mounting means, is subjected during coupling to an associated handling device, such as a spindle of a machine tool in the form, for example, of a drilling machine, lathe or milling machine, during operation of a clamping system provided on the handling device. Any component provided with a suitably adapted clamping system for coupling of a tool support part including, for example, a further tool system module, can be regarded as such a handling device.
DISCUSSION OF THE BACKGROUND
In the course of industrial development of modern manufacturing installations equipped with automatic tool-changing systems, the need for tool systems of modular construction has become increasingly greater. As an example, there is used in the basic tool mounting means of such systems a clamping shank manufactured with great precision, to which shank a system of different tools can be coupled. The coupling or clamping system for coupling the basic tool mounting means, an example of which is an HSK (hollow-shank taper) mounting means to a machine-tool spindle must meet stringent requirements as to stable and nonpositive connection in the region of the interface between the components to be coupled. If, for example, the actual pulling-in force is smaller than the specified pulling-in force stipulated by the machine manufacturer, the dynamic relationship between machine-tool spindle and basic tool mounting means deteriorates. This leads to a reduction of cutting performance, increased tool wear, possibly even tool break, shorter useful life, poorer attainable surface quality and stress on the machine-tool spindle and guideways. The magnitude and constancy of the pulling-in force is therefore of paramount importance for coupling of a basic tool mounting means to a machine-tool spindle.
Not only conventional steep-taper interfaces but also numerous other manufacturer-specific interfaces are used in industry as interface connections. The main types, however, are the hollow-shank taper interfaces, in which an axial extension of a component such as the aforementioned basic tool mounting means, which extension is constructed as a hollow-shank taper, is pulled into a matching mounting means on a handling device such as the aforementioned machine-tool spindle, during operation of a clamping system such as a three-claw clamping system.
To ensure the function of the clamping system, or in other words the necessary clamping or pulling-in force, all clamping systems must have the technical test capability of measuring the pulling-in force. The devices for measuring pulling-in force that are now commonplace operate electronically and, because of extremely complex techniques involving strain gauges, are relatively expensive and sensitive to shock and dirt under production conditions. In addition, electronic devices for measuring pulling-in force require a supply of energy from, for example, the power line or batteries.
As an example, there is known from German Unexamined Application 3829846 an electronic system for measuring the pulling-in force of tool-clamping jigs of machine tools, which are provided with a spindle tool mounting means for a tool shank and a clamping member for axially clamping the tool shank on the tool mounting means. The system for measuring pulling-in force comprises a test shank formed in one piece on the tool mounting means and designed for clamping connection to the clamping member, which shank is provided with a measuring member influenced by the clamping force for influencing a sensing device for the clamping force. The measuring member is a measuring body which senses the clamping force by mechanical deformation, and which can comprise, for example, one or more strain gauges.
SUMMARY OF THE INVENTION
The object of the present invention is now to provide, for measuring the pulling-in force to which a tool support part is subjected during coupling to an associated handling device, a device for measuring pulling-in force which, compared with the conventional devices for measuring pulling-in force, is inexpensive, impact-resistant, insensitive to dirt, of compact construction and operates independently of external energy.
This object is achieved by a device for measuring pulling-in force according to the features of claim
1
.
According to the invention there is provided a device for measuring pulling-in force in which the pulling-in force on a pulling-in part is measured on the basis of a certain physical effect, in which a well-defined relationship exists between the force applied to the deformation body via the pulling-in part and the resulting change of shape of the deformation body. Depending on the structural design and the functional interaction of the individual components of the device for measuring pulling-in force, the pulling-in force exerted on the pulling-in part can be transmitted as a tensile or compressive force to the deformation body, whereby the deformation body is subjected to corresponding elongation or compression. From the associated change in length of the deformation body, the force applied to the deformation body and thus to the pulling-in part can ultimately be measured in simple manner, for example by means of a mechanical force transducer, on the basis of the well-defined relationship between force and length change. The inventive device for measuring pulling-in force can therefore operate purely mechanically and completely independently of the power line or batteries. Furthermore, it is characterized by a structure which is relatively simple and therefore inexpensive from the engineering viewpoint, and which can be used successfully in the simplest form without any electronics.
The inventive device for measuring pulling-in force is also characterized by great flexibility of use. Essentially it can be used for measuring the clamping force of all interface clamping systems, or in other words on all common interface connections in which two parts to be coupled are clamped axially to one another. As an example, if the pulling-in force of a basic tool mounting means is to be measured in a mounting means provided on a machine-tool spindle, the inventive device for measuring pulling-in force is coupled instead of the basic tool mounting means to the machine-tool spindle. The inventive device for measuring pulling-in force is therefore provided with constructively essential features that can also be found in a basic tool mounting means, or in other words a support surface which, during coupling to the machine-tool spindle, becomes braced against a support surface provided thereon, as well as a pulling-in part that functions as the pulling-in shank of the basic tool mounting means and that is subjected to the pulling-in force of the clamping system. In contrast to the basic tool mounting means, however, the support surface in the inventive device for measuring pulling-in force is constructively separate from the pulling-in part functioning as the shank, and so the pulling-in part can be moved relative to the support part. The support part and the pulling-in part are connected to one another, as described hereinabove, by the deformation body.
Advantageous embodiments of the inventive device for measuring pulling-in force are subject matter of the dependent claims.
In the improvement according to a second example, the deformation body is also advantageously chosen and, in view of the maximum forces to be expected during operation of the clamping system, is dimensioned such that it is subjected to elastic deformations during operation of the clamping system. In this case a linear force-deformation relationship can be used for measurement of the pulling-in force.
The choice of support-surface pair between the support part and the handling device as annular plane surfaces according to a third example permits stable coupling, free of transverse forces, of the inventive device fo
Guehring Joerg
Noori Max
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