Conventional universal milling machine

Abstract

Conventional universal milling machine (1), comprising: - a milling head (8) with a drivable work spindle (9), - a milling table (5) as a holder for a workpiece (6) to be machined, - a first feed drive for moving the milling table (5) along a horizontal X-axis, - a second feed drive for moving the milling table (5) along a vertical Z-axis, - a mechanical feed lever (10) for the X-axis and the Z-axis, which is movable between a switching position in which the first or the second feed drive is switched on, and a neutral position in which the feed drives are switched off, characterized by that the universal milling machine (1) has a sensor (11) for detecting the position of the mechanical feed lever (10), wherein an electric drive of a feed drive can only be switched on when the mechanical feed lever (10) is in the neutral position.

Description

[0001] The invention relates to a conventional universal milling machine, comprising a milling head with a drivable work spindle, a milling table as a holder for a workpiece to be machined, a first feed drive for moving the milling table along a horizontal X-axis, a second feed drive for moving the milling table along a vertical Z-axis, and a mechanical feed lever for the X-axis and the Z-axis, which is movable between a switching position in which the first or the second feed drive is switched on, and a neutral position in which the feed drives are switched off.

[0002] Universal milling machines are machine tools used for milling a wide variety of workpieces. They have multiple axes, enabling complex machining operations such as the production of grooves, pockets, contours, or free-form surfaces. The machines typically consist of a machine bed, a milling head, feed devices, and a control unit.

[0003] Safety technology for universal milling machines includes measures and devices designed to protect operators and the machine. These include mechanical safety devices such as protective hoods, light barriers, emergency stop switches, two-hand controls, and electronic monitoring systems. Safety-relevant sensors detect, for example, the opening of safety doors, unauthorized movements, or the exceedance of critical operating parameters. The integration of safety controls and relays ensures that the machine is automatically shut down or placed in a safe state in the event of danger.

[0004] Currently, safety during operation of universal milling machines relies primarily on mechanical switches and stops for controlling the feed levers. However, these purely mechanical solutions have significant weaknesses: the feed levers can remain in an active position after the power has been switched off by pressing the emergency stop button or during maintenance work if the feed levers are forgotten to be moved back to the neutral position. It is also possible for a feed lever to be operated when the drive is switched off. This creates the risk of inadvertent movement of the axes when the machine is switched back on, i.e. when the drive is activated, if the user does not check the position of the feed levers before switching the machine on. In such cases, there is a risk of tool breakage, machine damage, or even injury to the operating personnel.

[0005] The invention is therefore based on the object of providing an improved universal milling machine in which unwanted movements of an axis during switching on are avoided.

[0006] To achieve this object, a conventional universal milling machine of the type mentioned at the outset is provided according to the invention with a sensor for detecting the position of the mechanical feed lever, wherein an electric drive of a feed drive can only be switched on when the mechanical feed lever is in the neutral position.

[0007] The invention is based on the finding that operational reliability can be increased and operating errors avoided by detecting the position of the mechanical feed lever using a sensor. The mechanical feed lever is used to select and activate the respective feed drive. In the switched position of the feed lever, either the first or second feed drive is activated to move the milling table in the desired axis. In the neutral position, both feed drives are deactivated, preventing any movement of the milling table.

[0008] Integrating a sensor to detect the position of the mechanical feed lever ensures that the electric drive of a feed drive can only be activated when the mechanical feed lever is in the neutral position. This prevents the feed drive from being inadvertently activated while the lever is in a switching position, which could lead to unwanted movement of the milling table and potentially hazardous situations.

[0009] This universal milling machine, thanks to the described arrangement, enables particularly safe operation, as the engagement of the feed drives is linked to the correct position of the mechanical feed lever. This significantly reduces the risk of operating errors and resulting damage to the workpiece, the machine, or personnel.

[0010] In a preferred embodiment, the sensor can be designed as a ring sensor that surrounds the mechanical feed lever. Such a ring sensor enables particularly reliable and precise detection of the position of the feed lever, as it completely encloses the feed lever and thus operates independently of the direction of rotation or the position of the feed lever.

[0011] In one possible embodiment, the neutral position of the mechanical feed levers can be electrically monitored by attaching a sensor, particularly a ring sensor, to the machine with a special mount. This mount encloses the feed lever and thus enables reliable detection of the lever position. In this embodiment, the feed drive can only be released when all feed levers are in the neutral position. Alternatively, other technical implementations for monitoring the lever position are also conceivable, for example, through the use of proximity switches or other suitable sensors.

[0012] The ring sensor is preferably designed as an inductive, capacitive, or optical sensor. The ring-shaped arrangement allows the sensor to detect movements or changes in the position of the feed lever in all directions, further increasing the safety of the universal milling machine.

[0013] The ring sensor can be mounted in a special bracket on the machine body, allowing for easy retrofitting or maintenance. It is also possible to combine the ring sensor with other sensors, for example, for redundancy or to record additional operating parameters.

[0014] The advantage of using a ring sensor is that no mechanical coupling is required between the sensor and the lever, reducing wear and maintenance. Furthermore, the ring sensor can be designed to be insensitive to contamination or vibrations in the machine environment.

[0015] It goes without saying that other sensor types can also be used, provided they ensure reliable detection of the lever position. However, the ring sensor design represents a particularly advantageous option for improving the functionality and safety of the universal milling machine.

[0016] In a preferred embodiment, the sensor can be designed as a non-contact sensor. The use of a non-contact sensor offers the advantage that no mechanical connection is required between the sensor and the mechanical feed lever. This reduces wear and maintenance costs, as no moving parts are stressed and the sensor is not exposed to any mechanical load.

[0017] In a further preferred embodiment, the universal milling machine can additionally have a mechanical feed lever for the Y-axis. This feed lever can be moved between a switching position in which a third feed drive for the Y-axis is switched on, and a neutral position in which the feed drive is switched off. A second sensor is assigned to the mechanical feed lever for the Y-axis, which is designed to detect the position of the mechanical feed lever for the Y-axis. The electric drive of the third feed drive for the Y-axis can only be switched on when the mechanical feed lever for the Y-axis is in the neutral position. This arrangement also enables reliable and safe control of the feed drive for the Y-axis, thereby further reducing the risk of incorrect operation or unintentional movements of the milling table.

[0018] Optionally, the second sensor can be designed similarly to the sensor for the X and Z axes, for example, as a non-contact sensor or a ring sensor. The sensor can also be mounted on a fixed bracket on the machine body to ensure stable and precise detection of the lever position. Integrating a sensor for the Y-axis feed lever contributes to increasing the overall operational reliability of the universal milling machine and enabling error-free operation in all axes.

[0019] In addition, a preferred embodiment can provide for a switch pin to be attached to the feed lever for the Y-axis, which mechanically detects the position of the feed lever for the Y-axis. This sensor can also be mounted on a special bracket. This technical implementation ensures that the feed motor for the Y-axis can only be activated when the feed lever is in the neutral position. The use of a switch pin enables particularly reliable and unambiguous detection of the lever position.

[0020] According to a further preferred embodiment, the second sensor, which is assigned to the mechanical feed lever for the Y-axis, can be designed as a contactless sensor. This sensor can operate inductively, capacitively, or optically, for example, and thus detect the position of the feed lever for the Y-axis without mechanical contact.

[0021] In a further preferred embodiment, the second sensor, which is assigned to the mechanical feed lever for the Y-axis, can be arranged near a rotational axis of this feed lever. Such positioning of the sensor can, for example, contribute to making the detection of the lever position particularly precise and reliable, since lever movements in the immediate vicinity of the rotational axis can be detected particularly well.

[0022] In a further preferred embodiment, the mechanical feed lever for the Y-axis can have a projection or extension. This projection or extension can be part of the second sensor or be designed such that its position can be detected by the second sensor. For example, the projection can be designed as a switching pin, flag, tab, or as a specially shaped attachment that is firmly connected to the feed lever.

[0023] In the universal milling machine according to the invention, it is preferred that the signals supplied by the sensors be integrated into an electrical enable circuit for the feed drives. The electrical enable circuit is designed such that a feed drive can only be activated when all feed levers—i.e., for the X-axis, the Y-axis, and the Z-axis—are in the neutral position. The sensor signals can be integrated into the enable circuit, for example, by connecting the sensor signals in series or by electronic evaluation in the machine control system. This ensures that the feed drive can only be activated when none of the axes is held in a switching position by a feed lever.

[0024] The invention is explained below using an exemplary embodiment with reference to the drawings. The drawings are schematic representations and show: Fig. 1 the essential components of a conventional universal milling machine; Fig. 2 a front view of the feed lever and a sensor; Fig. 3 a side view of the feed lever of Fig. 2; Fig. 4 a perspective view of the feed lever of Fig. 2; Fig. 5 shows another embodiment of a feed lever in the neutral position with a sensor; Fig. 6 a perspective view of the Fig. 5 shown feed lever; and Fig. 7 the in Fig. 5 shown feed lever in the switching position.

[0025] The Fig. The conventional universal milling machine 1 shown in Figure 1 essentially comprises a machine body 2 with a base 3 and a console 4 to which a milling table 5 is attached. The milling table 5 serves as a support for a workpiece 6 to be machined. By means of a first feed drive, the milling table 5 can be moved along a horizontal X-axis. A second feed drive serves to move the milling table 5 along a vertical Z-axis.

[0026] A cross slide 7 is mounted on the machine body 2 and is movable along a Y-axis. A milling head 8 with a work spindle 9 is located on the cross slide 7.

[0027] A schematically illustrated mechanical feed lever 10 for the X-axis and the Z-axis is arranged on the machine body 2. The drive of the milling table 5 can be switched on and off using the mechanical feed lever 10, so that the milling table 5 can be moved along the respective axis in the plus or minus direction.

[0028] The universal milling machine 1 has an emergency stop switch (not shown), which, when activated, immediately switches off and stops all drives to prevent damage or injuries. If the universal milling machine is subsequently switched on again and the mechanical feed lever is still in the switch position, the corresponding axis is immediately set in motion, which could result in a dangerous situation. To avoid this risk, a sensor 11 (schematically shown) is provided that is capable of detecting the position of the feed lever 10. Accordingly, the sensor 11 can detect whether the mechanical feed lever 10 is in the neutral position, in which none of the drives are switched on, or whether it is in a switch position.In this case, if the mechanical feed lever 10 is not in the neutral position, the switching on of the electric drive of a feed drive is blocked.

[0029] The Fig. 2 to 4 show the sensor 11 attached to the feed lever 10, wherein Fig. 2 a front view, Fig. 3 a side view and Fig. 4 is a perspective view. In the illustrated embodiment, the sensor 11 is designed as a ring sensor that surrounds the mechanical feed lever 10. The ring sensor is formed by a plate 12 that has a circular recess 13. It is a non-contact sensor that inductively detects whether the feed lever 10 is in the neutral position. The sensor 11 is fixedly arranged on the machine body 2 of the universal milling machine 1 by means of a holder 14. The sensor 11 generates a signal that is assigned to the respective position of the feed lever 10. The signal indicates whether the feed lever 10 is in the Fig. 2 to 4. In the neutral position, the feed lever 10 is located in the center of the circular recess 13 of the plate 12. When the feed lever 10 is in a switching position, the distance between the feed lever 10 and the sensor 11, which is designed as a ring sensor, is reduced at one point. In this state, another sensor signal is generated, indicating that the feed lever 10 is not in the neutral position.

[0030] The sensor signal supplied by sensor 11 is integrated into an electrical enable circuit for the X-axis and the Z-axis. The respective feed drive assigned to these axes can only be switched on when the feed lever 10 is in the neutral position.

[0031] The one in the Fig. 5, Fig. 6 and Fig. The mechanical feed lever 15 shown schematically in Figure 7 is assigned to the Y-axis. A third feed drive can be switched on or off using the feed lever 15. Fig. 5 and Fig. In the neutral position shown in Figure 6, the third feed drive is switched off.

[0032] On its underside, the mechanical feed lever 15 has a pin-like extension 16 located opposite a sensor 17. The distance between the pin-like extension 16 and the sensor 17 is reduced. The sensor 17 is designed as a non-contact sensor and is fixedly mounted on the machine body 2 of the universal milling machine 1 by means of a schematically illustrated holder 18.

[0033] Fig. 7 is a similar view to Fig.5 and shows the mechanical feed lever 15 in the deflected state, i.e., in the switching position. The feed lever 15 is in this position when an operator has switched on the feed drive for the Y-axis. This moves the work spindle 9 along the Y-axis away from or toward the machine body 2.

[0034] In certain cases, for example after actuating an emergency stop switch or after a power failure, the feed lever 15 may inadvertently still be in the switch position when switched back on. In this case, the non-contact sensor 17 detects that the pin-like extension 16 attached to the feed lever 15 is not in the neutral position relative to the non-contact sensor 17. In this way, it can be determined whether the feed lever 15 is in the neutral position or in an undefined position, e.g., in the switch position. The sensor 17 is integrated into an electrical release circuit for the Y-axis. In this situation, switching on of the feed drive for the Y-axis is prevented. The feed drive can only be switched on again after the feed lever 15 has been moved back to the neutral position. List of reference symbols 1 universal milling machine 2 machine bodies 3 feet 4 Console 5 milling table 6 Workpiece 7 cross sections 8 milling head 9 work spindle 10 feed levers 11 Sensor 12 plates 13 Recess 14 Bracket 15 feed lever 16 Extension 17 Sensor 18 Bracket

Claims

[1] Conventional universal milling machine (1), comprising: - a milling head (8) with a drivable work spindle (9), - a milling table (5) as a holder for a workpiece (6) to be machined, - a first feed drive for moving the milling table (5) along a horizontal X-axis, - a second feed drive for moving the milling table (5) along a vertical Z-axis, - a mechanical feed lever (10) for the X-axis and the Z-axis, which is movable between a switching position in which the first or the second feed drive is switched on, and a neutral position in which the feed drives are switched off, characterized by , that the universal milling machine (1) has a sensor (11) for detecting the position of the mechanical feed lever (10), wherein an electric drive of a feed drive can only be switched on when the mechanical feed lever (10) is in the neutral position. [2] Conventional universal milling machine according to claim 1, wherein the sensor (11) is designed as a ring sensor and surrounds the mechanical feed lever (10). [3] Conventional universal milling machine according to claim 1 or 2, wherein the sensor (11) is mounted on a holder fixedly arranged on a machine body (2). [4] Conventional universal milling machine according to one of the preceding claims, wherein the sensor (11) is designed as a contactless sensor. [5] Conventional universal milling machine according to one of the preceding claims, wherein a mechanical feed lever (15) for the Y-axis, which is provided between a switching position in which a third feed drive for the Y-axis is switched on, and a neutral position in which it is switched off, to which a second sensor (17) is assigned, which is designed to detect the position of the mechanical feed lever (15) for the Y-axis, wherein an electric drive of the third feed drive for the Y-axis can only be switched on when the mechanical feed lever (15) for the Y-axis is in the neutral position. [6] Conventional universal milling machine according to claim 5, wherein the second sensor (17) is designed as a non-contact sensor. [7] Conventional universal milling machine according to claim 5 or 6, wherein the second sensor (17) is arranged near a rotation axis of the mechanical feed lever (15) for the Y-axis. [8] Conventional universal milling machine according to claim 7, wherein the mechanical feed lever (15) for the Y-axis has a projection or an extension (16) which is a component of the second sensor or whose position can be detected by the second sensor (17). [9] Conventional universal milling machine according to one of claims 5 to 8, wherein the sensor signals supplied by the first sensor (11) and the second sensor (17) are integrated into an electrical enabling circuit for the first to third feed drives and a feed drive can only be switched on when the feed levers (10, 15) for the X-axis, the Y-axis and the Z-axis are in the neutral position.

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