DE202021105213U1 - Mobile, electrical clamping device - Google Patents

Abstract

Mobile, electrically operated clamping device (T), in particular a vice, for temporary arrangement in a machine tool in order to release or clamp a workpiece to be held by the clamping device (T), the clamping device (T) comprising: a) an electric motor (M) for Drive at least one clamping element (K1, K2) movable in a longitudinal direction (X), andb) a rechargeable accumulator (A) for storing and providing electrical energy for the electric motor (M), andc) a wireless communication interface (S) for communication with a higher-level controller (C), in order to transmit operating or control signals to this higher-level controller (C) or to receive them from it.

Description

The present invention relates to a mobile, electrical clamping means, in particular a vice, for temporary arrangement in machine tools.

It is known from the prior art to fix workpieces or other components in a machine tool with the aid of clamping means, which are often vices. Such vices are usually controlled via the control unit of the machine tool, for which purpose corresponding control lines and connections (electrical, hydraulic or pneumatic) must be led to the vise. In particular in the case of moving, for example rotatable, machine beds, the connection of the vice is complicated, since control or supply lines usually have to be routed through the center of rotation of the table and there must be equipped with rotatable couplings. The use of a vice controlled by a machine tool therefore requires a close connection to the control or infrastructure of the machine.

The object of the invention was to offer a mobile clamping means that can be used flexibly, in particular a vice, that can be inserted into the machine control of a machine tool and at the same time easily operated.

The object is achieved by a clamping means according to claim 1, an arrangement according to claim 7 and a use according to claim 8.

The invention is based on the knowledge of being able to provide a clamping device, in particular a vice, mobile and detached from the machine control of a machine tool by equipping the vice with an electric motor and a battery supplying it as well as a wireless communication interface in order to control the vice and provide operating signals to be able to retrieve. At the same time, the external supply of electrical energy or the connection of control lines can be completely dispensed with, so that cumbersome cable bushings in the machine bed of the machine tool or the connection of the vice to the control of the machine tool can advantageously be omitted - the vice is independent and communicates with one of the machine tool control provided separately, higher-level control via its wireless communication interface. Hydraulic, pneumatic or electrical lines do not have to be provided within the machine tool or released again after production, which advantageously greatly simplifies the handling of the clamping means. The wireless connection specifically avoids the connection of signal cables and offers the greatest possible flexibility in the arrangement of the higher-level control, which can also be spatially spaced apart from a machine tool in which the clamping device is used.

Operating or control signals for monitoring the manufacturing process can be transmitted via the wireless communication interface to the higher-level control outside of or separately from the machine tool or its control and evaluated there. With bidirectional data transmission, the vice can also be actively controlled via the interface, for example by controlling the electric motor of the vice to rotate in order to clamp or release a workpiece. A galvanic connection to other signal lines or the supply of external air, water, oil, electricity, etc. to maintain the clamped state and for wireless communication with the external control is also preferably not necessary, so that the vice in the workroom of a machine tool is relative to this can be operated independently.

The embodiment of the clamping device according to the invention, preferably designed as a vice, accordingly provides that the clamping device can be transferred from a released state to a clamping state and back in order to release or clamp a workpiece to be held by the clamping device. An electric motor is also provided for driving at least one clamping element that can be moved in a longitudinal direction. The clamping element can in particular be the clamping jaw of a vice.

A rechargeable accumulator stores the electrical energy required to operate the clamping device and makes it available in particular to the motor and a wireless communication interface that is also provided in order to be able to communicate with a higher-level controller. The accumulator can also supply other control elements, sensors or other electronic components of the clamping means with power. “Wireless communication interface” should not only refer to the pure physical interface, but also the associated data processing and transmission components that are required for the wireless transmission and reception of signals. The data transmission can take place, for example, via a wireless local area network (WLAN).

The clamping means preferably comprises two drive shafts in a longitudinal direction with the aid of a common drive shaft designed as a spindle X clamping elements that can be moved against one another. In the case of an embodiment as a vice, these could be two clamping jaws lying opposite one another in the X direction, between which a workpiece can be clamped. For this purpose, the spindle driven directly or indirectly by the electric motor can have two counter-rotating threaded spindle sections, one of the clamping elements being coupled to a spindle nut in each case. By rotating the common spindle, the clamping elements then move towards or away from one another, depending on the direction of rotation.

With the aid of the wireless communication interface, the clamping device according to the invention is advantageously designed to transmit signals from which the current state of the clamping device can be derived. In particular, these can be position signals that are detected with the aid of a measuring system and indicate the position of at least one clamping device along the X direction. With the help of an evaluation in the higher-level control unit, it can be determined whether or how far apart the clamping elements of the clamping device (in the special case the clamping jaws of the vice) are located in order to be able to insert or remove a workpiece. The correct position of a clamped workpiece can also be determined or monitored (indirectly via the position of the clamping elements) with the aid of the measuring system. In particular, a measuring system is conceivable which detects the X position of a tensioning element via a conductive plastic potentiometer. If two clamping elements are moved over a common shaft or spindle with opposite inclination according to the example described above, then it is sufficient to detect the X position of one of the two clamping elements in order to derive the position of the other clamping element therefrom.

Alternatively, it is conceivable to also detect the X position of a tensioning element via the rotary movement of a drive element by means of an encoder or via other displacement measuring systems familiar to a person skilled in the art.

1. a) die X-Position wenigstens eines Spannelements (K₁ , K₂ ), und/oder
2. b) den Ladezustand des Akkumulators (A), und/oder
3. c) die Temperatur an wenigstens einer Messstelle des Spannmittels (T) und/oder
4. d) die Drehlage wenigstens einer Antriebskomponente, und/oder
5. e) eine Kraft oder ein Drehmoment, welche bzw. welches von einer Antriebskomponente erzeugt wird oder auf diese einwirkt, und/oder
6. f) die Anzahl der nach vorgebbaren Bedingungen erfassten Betriebsstunden oder Klemmzyklen, und/oder
7. g) die Stromaufnahme des Motors (M).

According to an advantageous embodiment of the invention, the clamping means is designed to transmit various operating signals via the wireless communication interface. These signals can relate in particular to:

1. a) the X position of at least one clamping element ( K ₁ , K ₂ ), and or
2. b) the state of charge of the accumulator ( A. ), and or
3. c) the temperature at at least one measuring point of the clamping device ( T ) and or
4. d) the rotational position of at least one drive component, and / or
5. e) a force or a torque which is generated by a drive component or acts on it, and / or
6. f) the number of operating hours or clamping cycles recorded according to specifiable conditions, and / or
7. g) the current consumption of the motor ( M. ).

The signals can be evaluated in particular to detect a critical operating state in good time and to switch off the machine tool if, for example, the X position or positions of the clamping elements indicate that a workpiece is no longer correctly clamped. A corresponding signal could be output by the higher-level control unit to an operator in order to switch off the machine tool accordingly. Other solutions for signal processing and forwarding for the purpose of disconnection are also conceivable.

The tensioning means according to the invention can also have a memory in order to store operating data temporarily or permanently and to read out or write them using the wireless communication interface. In addition, the clamping means can also have a wired or galvanic interface that can be used during breaks in operation for reading out or writing to the memory.

When the workpiece is clamped, the shaft (spindle) driving the clamping elements with the associated spindle nuts or clamping elements is usually in a state of static friction. In order to release the clamping state, a higher torque must therefore be transmitted to the spindle than would be required for the other movement of a clamping element in the X direction, that is to say without generating a clamping force. Instead of having to apply the increased torque via a backlash-free gear train through the electric motor, an advantageous embodiment of the invention instead provides for a certain kinetic energy to be introduced into a gearbox coupled to the motor before the gear train is coupled to the spindle to release the clamping . The gearbox “picks up momentum”, so to speak, before it suddenly hits the spindle with an impulse and, using the kinetic energy that has built up up to that point, pulls it out of the static friction state. This protects the motor and the accumulator, which otherwise would have to use a disproportionately large amount of energy to overcome the static friction state.

This is implemented in practice by means of two components of the drive that can be rotated concentrically to one another about a common axis of rotation, namely a drive element (for example a Spur gear), and an output element (for example formed by the spindle already mentioned). The drive element has first stop means which interact with second stop means of the output element in a form-fitting manner in both directions of rotation, depending on the rotational position of the two elements with respect to one another. The first stop means are designed to act on the second stop means in a first circumferential direction around the axis of rotation (first act) in order to drive the output element in a first direction of rotation and to clamp a workpiece between the clamping elements. Conversely, when the direction of rotation changes, the first stop means also act on the second stop means in the opposite circumferential direction (second act of application) in order to drive the output element counter to the first direction of rotation and to loosen the workpiece.

• Zum Einspannen eines Werkstücks versetzt der Elektromotor das Antriebselement (beispielsweise das vorgenannte Stirnrad) unmittelbar oder mittelbar über einen Getriebestrang in einer ersten Drehrichtung in Rotation. Dadurch gelangen die ersten Anschlagmittel des Stirnrads spätestens nach einem Drehwinkel in der Größe des Freilaufwinkels α mit den zweiten Anschlagmitteln des Abtriebselements (beispielsweise denen der Spindel) in Eingriff („erste Beaufschlagung“), so dass diese zur Rotation angetrieben wird und die Spannelemente aufeinander zu bewegt, bis das Werkstück geklemmt ist. In diesem geklemmten Zustand sind die Spannelemente und die sie antreibende Spindel durch Haftreibung miteinander verbunden.

According to the invention, it is crucial that the drive element, when changing from the first to the second application or vice versa, can be rotated by a predeterminable freewheel angle (α> 0 °) without being in operative connection with the output element or driving it - a form-fitting coupling for torque transmission does not exist during this time. According to the aforementioned principle, this freewheeling angle is used to build up sufficient kinetic energy in the drive train before the drive element “hits” the output element again in the opposite direction. The angle α could be arbitrary; it is preferably 60 °, 90 ° or even 120 °, for example. The process could be as follows:

• To clamp a workpiece, the electric motor sets the drive element (for example the aforementioned spur gear) in rotation directly or indirectly via a gear train in a first direction of rotation. As a result, the first stop means of the spur gear come into engagement (“first impingement”) with the second stop means of the output element (for example those of the spindle) after an angle of rotation equal to the size of the freewheel angle α, so that it is driven to rotate and the clamping elements approach one another moved until the workpiece is clamped. In this clamped state, the clamping elements and the spindle driving them are connected to one another by static friction.

To release the clamping, the motor is activated in the opposite direction of rotation, which means that the spur gear also rotates in the opposite direction. At first, the stop means of the spur gear detach from those of the spindle (first action is released) and move along the freewheel angle α in the opposite direction. In the meantime, the gear train and with it the spur gear accelerate to a certain speed, while at the same time a corresponding kinetic energy, in particular rotational energy, is built up in the gear train. When the first stop means of the spur gear meet the second stop means of the spindle in the opposite direction at the end of the freewheel angle α (second action), the kinetic energy built up in the gear train is suddenly transferred to the spindle with a sufficiently high impulse, which leads to overcoming the static friction is sufficient and the clamping is released without the motor being subjected to excessive load.

The arrangement of a clamping device according to the invention in a machine tool represents an advantageous application of the invention. The machine tool can be controlled by a machine tool controller, while the clamping device is designed to send operating or control signals via the wireless communication interface to a higher-level controller that is separate from the machine tool controller to be transmitted and / or received from it. A coupling with the machine tool takes place at most in mechanical terms, in that the clamping means is fastened in the machine bed of the machine tool.

• 1 eine vereinfachte perspektivische Darstellung eines als Schraubstock ausgebildeten Spannmittels;
• 2 das Spannmittel gemäß 1 in geschnittener Darstellung;
• 3 eine weitere Schnittdarstellung des Spannmittels gemäß 1 und 2;
• 4 die Anordnung eines erfindungsgemäßen Spannmittels in einer Werkzeugmaschine;
• 5 eine Schnittansicht zur Darstellung des Antriebsstrangs mit Spindel;
• 5a, 5b vergrößerte Teilansichten aus den 2 und 5.

An embodiment of the clamping means according to the invention is to be explained in more detail below with the aid of figure examples. It shows

• 1 a simplified perspective view of a clamping means designed as a vice;
• 2 the clamping device according to 1 in cut representation;
• 3 a further sectional view of the clamping means according to 1 and 2 ;
• 4th the arrangement of a clamping device according to the invention in a machine tool;
• 5 a sectional view showing the drive train with spindle;
• 5a , 5b enlarged partial views from the 2 and 5 .

1 shows a clamping device according to the invention in the form of a vice T . The vice comprises two clamping elements designed as clamping jaws K ₁ and K ₂ running in a longitudinal direction X or are movable in the opposite direction towards and away from one another in order to clamp or release an intermediate workpiece.

The vice T is with a wireless communication interface S. equipped with a higher-level control above it C. Exchange signals. The wireless communication interface S. is shown in simplified form in the figures by a stylized radio element, but also includes additional electronic components (not shown) required for the wireless transmission, reception or processing of signals.

2 shows the inner workings of the vice in a simplified sectional view T according to 1 . An electric motor is located in an unspecified housing M. arranged by an accumulator A. is supplied with electrical energy and via a gear train F. the two clamping elements K ₁ and K ₂ actuated. A drive element designed as a spur gear W ₁ is with an output element designed as a spindle W ₂ connectable. Two counter-rotating spindle threads of the output element W ₂ each engage in a spindle nut G ₁ , G ₂ one, in turn, each with one of the clamping elements K ₁ and K ₂ are connected. By rotating the spindle W ₂ the clamping elements move K ₁ and K ₂ - depending on the direction of rotation of the spindle - towards or away from one another.

The vice T also contains in 2 Control elements not shown in more detail in order to be able to control the electric motor in a suitable manner. The control signals for this are sent via the in 2 Also not shown, wireless communication interface from the higher-level controller C. provided. Also, the vice can T have various sensors (temperature sensor, force sensor, position sensor etc.) in order to detect certain operating conditions and via the wireless communication interface S. to signal.

An example of position detection is shown 3 . There is a measuring system in the upper area of the vice B. arranged to the respective X position of the clamping element K ₂ capture. The measuring system B. is equipped with a conductive plastic potentiometer and designed to select one of the respective X-position of the clamping element K ₂ to generate dependent signal value and via the wireless communication interface S. to spend. In the case of symmetrical spindle threads, the X position of the one clamping element K ₂ also the X position of the other tensioning element, which is symmetrical to a central position K ₁ , and thus determine the opening dimension of the vice.

The clamping device according to the invention T is particularly suitable for use in machine tools, as in 4th shown in greatly simplified form. A clamping device designed as a vice T is for this on the machine bed H in the machining area of a machine tool R. attached to receive a workpiece to be machined. The machine bed H can be designed to be rotatable. The machine tool R. has a machine tool control connected to it E. , via which the machining spindles (not shown in detail) or the movement of the axes are controlled in a manner known to those skilled in the art.

It would be technically difficult and complex to connect the vice with connection lines for the power supply and signal transmission and to the machine tool control E. to be connected because, for example, rotary movements of the machine bed H require corresponding couplings in the supply lines. In addition, loosening the connections after using the vice is also time-consuming. Instead, the vice is T according to the invention independently and separately from the machine tool control E. controllable with the help of the higher-level controller C. and the wireless communication interface communicating with it S. of the vice.

5 in connection with the enlarged representations in 5a and 5b shows a particular embodiment of a clamping device designed as a vice T in a simplified section perpendicular to the longitudinal direction X . You can see the already in 2 described coupling of the drive element designed as a spur gear W ₁ with the output element designed as a spindle W ₂ . Spindle and spur gear rotate about a common one, in the longitudinal direction X running axis of rotation D. . The spur gear W ₁ of the gear train F. is with three first slings distributed on an inner circumference P ₁ equipped, which act as a driver radially inwards except for an inner radius r ₁ extend. One inside the spur gear W ₁ arranged portion of the spindle W ₂ is on an outer circumference in an analogous manner with three second stop means distributed over the circumference P ₂ equipped as a driver, which extend in the radial direction outwards to an outer radius r ₂ , whereby r ₂ is greater than r ₁ .

In a first direction of rotation of the spur gear W ₁ get its driver P ₁ with the drivers P ₂ in positive contact in the circumferential direction in order to transmit a torque in this direction to the spindle (“first application”). If the spur gear is driven in the opposite direction from the first application, the respective drivers initially detach from one another and the spur gear swivels about the freewheeling angle a around the spindle without applying torque to the spindle. Only when the driver P ₁ of the spur gear the driver P ₂ If the spindle is acted upon on the other side or in the opposite direction (“second application”), the spindle is also driven in the opposite direction. The position, size and number of the drivers distributed over the respective circumference determine the size of the freewheel angle a .

Became a workpiece in a vice T clamped by the spur gear W ₁ the drivers P ₂ the spindle W ₂ has driven, for example, in a first direction of rotation (first application) until the workpiece is fully clamped, the spindle is in static friction with the spindle nuts G ₁ , G ₂ tied together. In order to overcome the static friction when loosening the clamping, an increased coupling of the motor with the spindle would be an increased one from the motor M. Required torque to be applied in the opposite direction. The freewheel angle a instead, it allows the drive train in an inventive manner F. initially decoupled from the spindle to be driven in the opposite direction and accelerated to initially transfer kinetic energy to the drive train F. bring in. Only when the spur gear W ₁ the freewheel angle a has passed over, the respective stop means come into positive contact again in the opposite direction. The spindle is connected to the one in the gear train F. kinetic energy built up as rotational energy is applied suddenly, whereby the static friction can be overcome without significant additional load on the motor and the clamping can be released.

List of reference symbols

A.

accumulator

B.

Measuring system

C.

higher-level control

D.

Axis of rotation

E.

Machine control

F.

Gear train

G1, G2

Spindle nuts

H

Machine bed

K1, K2

Clamping elements

M.

engine

P1

first lifting gear

P2

second sling

R.

Machine tool

r1, r2

Inside radius, outside radius

S.

wireless communication interface

T

Clamping device

W1

Drive element

W2

Output element

X

Longitudinal direction

a

Freewheel angle

Claims (8)

Mobile, electrically operated clamping device (T), in particular a vice, for temporary arrangement in a machine tool in order to release or clamp a workpiece to be held by the clamping device (T), the clamping device (T) comprising: a) an electric motor (M) for Drive at least one clamping element (K ₁ , K ₂ ) that can be moved in a longitudinal direction (X), and b) a rechargeable accumulator (A) for storing and providing electrical energy for the electric motor (M), and c) a wireless communication interface (S) for communication with a higher-level controller (C) in order to transmit or receive operating or control signals to this higher-level controller (C). Clamping device (T) Claim 1 Comprising an output member (W ₂₎ and two with the aid of the output element (W ₂₎ are mutually movable in the longitudinal direction (X) tensioning elements (K _1, K _2), wherein the output member (W ₂₎ having two opposing threaded spindle sections, of which one is coupled to a clamping element (K ₁ , K _2). Clamping device (T) Claim 1 or 2 , comprising a measuring system (B) for determining the X position of at least one clamping element (K ₁ , K ₂ ). Clamping means (T) according to the preceding claim, wherein the measuring system (B) comprises a conductive plastic potentiometer. Clamping means (T) according to one of the preceding claims, wherein the clamping means (T) is designed to transmit operating signals via the wireless communication interface (S), and wherein the operating signals relate in particular to: a) the X position of at least one clamping element (K ₁ , K ₂ ), and / or b) the state of charge of the accumulator (A), and / or c) the temperature at at least one measuring point of the clamping device (T) and / or d) the rotational position of at least one drive component, and / or e) a force or torque which is generated by a drive component or which acts on it, and / or f) the number of operating hours or clamping cycles recorded according to predefinable conditions, and / or g) the current consumption of the motor (M). Clamping means (T) according to one of the preceding claims, a) comprising a drive element (W ₁ ) which can be driven directly or indirectly by the motor (M) and rotatable about an axis of rotation (D) with first stop means (P ₁ ), and b) further comprising a An output _{element (W 2} ) that is rotatable about the axis of rotation (D) and interacts with clamping elements (K _{1 , K 2} ) with second stop means (P ₂ ), c) the stop means (P ₁ ) being designed to support the stop means (P ₂ ) optionally ♦ to apply (first application) in a first circumferential direction around the axis of rotation (D) in order to drive the output _{element (W 2} ) in a first direction of rotation and _{to clamp a workpiece between clamping elements (K 1} , K ₂ ), or ♦ in the to act on the circumferential direction opposite to the first circumferential direction (second act on) in order to drive the output element (W ₂ ) against the first direction of rotation and to loosen the workpiece, d) the drive element (W ₁ ) when changing from the first can be rotated by a predeterminable freewheeling angle (a> 0 °) on the second application or vice versa, without driving the output element (W ₂ ). Arrangement of a clamping means (T) according to one of the preceding claims in a machine tool (R), the machine tool (R) being controllable by a machine tool control (E), while the clamping means (T) is designed to transmit operating or control signals via the wireless Communication interface (S) to be transmitted to and / or received from a superordinate control (C) which is embodied separately from the machine tool control (E). Use of a clamping device (T) according to one of the Claims 1 until 6th in a machine tool.

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