Drive device for a protective cover and method for adjusting a protective cover

Abstract

The invention relates to a drive device for a protective cover (2) of a machine, the drive device comprising a motor (5) which cooperates with a traction device (14) via a flywheel (7), the flywheel being arranged for loading via the weight of the protective cover (2) and for loading via a counterweight (15), wherein the flywheel (7) is designed such that it is blocked by a positive weight difference between the protective cover (2) and the counterweight (15).

Description

Technical Field

[0001] The invention relates to a drive device for a protective cover of a machine. The invention also relates to a method for motorized adjustment of a protective cover of a machine, the protective cover being partially released by a counterweight. Background Art

[0002] For example, machine tools with protective covers are described in documents EP 2682229 A2 and DE 7133603 U. In the latter case, a protective cover is provided in addition to a tubular protective jacket.

[0003] DE 9208537 U1 describes a press having a press plunger which can be moved against a workpiece, wherein a protective hood can be moved parallel to the direction of travel of the press plunger.

[0004] The circular saw described in US 2,593,596 A comprises a hood body which is loaded by spring tension or weight compensation and is intended to be maintained at any height above the machine deck.

[0005] Documents EP 3106738 A1 and EP 3343085 A1 disclose various devices for moving and locking a safety door which is arranged in front of a workstation to be secured.

[0006] Further locking mechanisms for doors are described in the publications DE 202018003076 U1, DE 202016006763 U1 and DE 202014101967 U1.

[0007] For example, a drive device with weight compensation for vertically moving a door is known from DE 202016002514 U1. In this case, a tensioning element guided by a deflection pulley is connected to a movable door leaf on the one hand and to a counterweight on the other hand. Summary of the invention

[0008] The invention is based on the object of further developing the drive of a protective cover arranged on a machine compared to the aforementioned prior art both from a safety point of view and from a production engineering point of view.

[0009] According to the invention, this object is achieved by a drive device having the features of claim 1. This object is also achieved by a method for motorized adjustment of a protective cover of a machine according to claim 9. The configurations and advantages of the invention explained below in conjunction with the adjustment method also apply accordingly to the drive device, and the configurations and advantages of the invention explained in conjunction with the drive device also apply accordingly to the adjustment method.

[0010] The drive device is used to raise and lower the protective cover of the machine, and the drive device includes a motor, which cooperates with the traction device via a flywheel, and the flywheel is arranged for loading via the gravity of the protective cover and for loading via a counterweight, wherein the flywheel is designed so that the flywheel is blocked due to the positive gravity difference between the protective cover and the counterweight.

[0011] In undisturbed operation, the mass of the protective cover introduces a force into the traction device which opposes the force exerted by the counterweight. The drive device must overcome the differential force plus any existing friction forces when moving the protective cover. This also applies accordingly if the weight of the protective cover and / or the weight of the counterweight acts on the traction device via the transmission mechanism.

[0012] When the protective cover is lowered, it is pulled downwards by its own weight. The motor of the drive device acts as a brake in this case. If the protective cover reaches an obstacle that stops the protective cover, the flywheel opens while the motor continues to run. This means that in this state, the motor is disconnected from the traction device. This prevents the drive torque or drive force from the motor from being introduced into the traction device.

[0013] Typically, a method for motorized adjustment of a protective cover partially released by a counterweight is characterized in that a flywheel is connected between a motor, in particular an electric motor, and the protective cover, wherein both raising and lowering of the protective cover is performed with the flywheel blocked.

[0014] After the protective cover has been stopped by the obstacle and the flywheel has thus opened automatically, the protective cover can be raised again if necessary by reversing the direction of the motor drive. The flywheel automatically returns to its blocking position.

[0015] As flywheels for the drive, linear flywheels are usually just as suitable as flywheels acting between rotating elements. In both cases, the flywheel can be designed as a friction-locking flywheel, for example a clamping roller flywheel or a wedge flywheel, or as a form-locking flywheel, in particular a ratchet flywheel. If the flywheel acts between the rotating elements, the flywheel can be arranged concentrically with the deflection wheel, on which a traction device, for example in the form of an open toothed belt, is guided.

[0016] According to various further embodiments, a reduction gear is connected between the motor and the flywheel. For example, in the case of a linear drive, this can be a spindle drive. On the other hand, if there is a flywheel effect between the rotating elements, a winding gear, such as a belt drive or a chain drive, is particularly suitable as a reduction gear. Toothed gears are also suitable as reduction gears.

[0017] Regardless of how the motor feeds power into the traction device that couples the protective cover to the counterweight, the traction device is designed as an open traction device. For example, instead of a toothed belt, the traction device can also be a chain.

[0018] Optionally, an alarm device is provided, which is triggered as soon as the protective cover moves against an obstacle. Such an alarm device can be integrated into the protective cover or attached to the protective cover. The alarm device can also be integrated into the drive device. In this case, the alarm device detects the opening of the flywheel. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Two exemplary embodiments of the present invention are described in more detail below with the aid of the accompanying drawings. In the drawings:

[0020] Figure 1 A first exemplary embodiment of a drive device for a protective cover of a machine is shown in a perspective view.

[0021] Figure 2 A second exemplary embodiment of a drive device for a protective hood is shown in a schematic diagram. DETAILED DESCRIPTION

[0022] Unless otherwise specified, the following description relates to two exemplary embodiments. In the two figures, components that correspond to each other or have substantially the same function are marked with the same reference numerals.

[0023] The machine 1 comprises a protective cover 2 for protecting an operator of the machine 1 , with the aid of which a manual workstation is arranged. The machine frame of the machine 1 is designated 4 . The protective cover 2 can be adjusted in a motorized manner with the aid of a drive device 3 .

[0024] The drive device 3 comprises an electric motor as motor 5, which interacts via a gear 6 designed as a reduction gear with a flywheel 7 which also belongs to the drive device 3. The drive-side element of the flywheel 7 is designated 8 and the driven-side element is designated 9.

[0025] The motor 5 actuates the traction device 14, which is an open toothed belt, via the gear 6 and the flywheel 7. The toothed belt 14 is loaded at one end by the weight of the protective cover 2 and at the other end by the counterweight 15. The load applied by the protective cover 2 is greater than the load applied by the counterweight 15, so that the protective cover 2 will move to its closed position, i.e., the protective cover is lowered, without additional force. The resultant force acting on the protective cover 2 is less than half of the weight of the protective cover 2. This corresponds to the fact that the mass of the protective cover 2 is largely, but not completely, compensated by the counterweight 15.

[0026] In accordance with Figure 1In the exemplary embodiment of the invention, the gear 6 is designed as a winding gear, i.e. a belt drive. The closed toothed belt of the belt drive 6 is designated 18. The flywheel 7 operated via the belt drive 6 has rotatable elements 8, 9 on both the drive side and the driven side. The elements 8, 9 of the flywheel 7 are arranged concentrically with the shaft 10 mounted in the machine frame 4. Furthermore, a deflection wheel 16 is arranged concentrically with the elements 9, 9 and thus with the entire flywheel 7, on which the open toothed belt 14 is guided. In this case, the flywheel 7 is designed as a clamping roller flywheel, i.e. a friction locking flywheel.

[0027] Regarding the design of flywheel 7, according to Figure 2 Exemplary embodiments and according to Figure 1 The exemplary embodiments are different: according to Figure 2 , the flywheel 7 is designed as a ratchet flywheel, i.e. a form-fitting locking flywheel. In this case, the flywheel 7 is a linear flywheel, i.e. a flywheel in which the drive element 8 and the driven element 9 can be moved in a linear manner. The blocking pawl 11 loaded by the spring element 13 engages in the blocking contour 12 when the flywheel 7 is blocked.

[0028] As in accordance with Figure 1 In the exemplary embodiment of the open toothed belt 14, Figure 2 In the exemplary embodiment of the invention, the deflection wheel 16 is also operated, wherein only in accordance with Figure 1 In the configuration of can be introduced into the deflection wheel 16 torque. Figure 2 In the arrangement of , the second deflection wheel 17 can be seen, on which the traction device 14 is guided.

[0029] In both exemplary embodiments, both the raising and lowering of the protective cover 2 takes place with the flywheel 7 blocked. This applies as long as the movement of the protective cover 2 is not disturbed, for example by obstacles located in the adjustment path. If the protective cover 2 encounters an obstacle during its downward movement, the obstacle indicates the release of the weight of the protective cover 2. The positive weight difference between the protective cover 2 and the counterweight 15, which is a prerequisite for blocking the flywheel 7, thus disappears. Therefore, while the motor 5 continues to run, the flywheel 7 opens, wherein the protective cover 2 resting on the obstacle only loads the obstacle with the weight difference existing between the protective cover 2 and the counterweight. Therefore, the protective function of the flywheel 7 is realized in a purely mechanical way.

[0030] Reference numerals list

[0031] 1 Machine 2 Protective cover 3 Drive device 4 Machine frame 5 Motor 6 Gear 7 Flywheel 8 Drive-side element of flywheel 9 Driven-side element of flywheel 10 Shaft 11 Blocking pawl 12 Blocking contour 13 Spring element 14 Traction device, open toothed belt 15 Counterweight 16 Deflection wheel 17 Deflection wheel 18 Closed toothed belt

Claims

1. A drive device for a protective cover (2) of a machine, the drive device comprising a motor (5), the motor cooperating with a traction device (14) via a flywheel (7), the flywheel being arranged for loading via the gravity of the protective cover (2) and for loading via a counterweight (15), characterized in that: The flywheel (7) is designed such that it is blocked due to the positive gravity difference between the protective cover (2) and the counterweight (15).

2. The driving device according to claim 1, characterized in that: The flywheel (7) is designed as a linear flywheel.

3. The driving device according to claim 1, characterized in that: The flywheel (7) is designed as an effective flywheel between two rotatable elements (8, 9).

4. The driving device according to claim 2 or 3, characterized in that: The flywheel (7) is designed as a friction locking flywheel.

5. The driving device according to claim 2 or 3, characterized in that: The flywheel (7) is designed as a form-fitting locking flywheel.

6. The driving device according to claim 1, characterized in that: A reduction gear (6) is connected between the motor (5) and the flywheel (7).

7. The driving device according to claim 6, characterized in that: The flywheel (7) is arranged concentrically with a deflection wheel (16), on which the traction device (14) is guided.

8. The driving device according to claim 1, characterized in that: An open toothed belt is provided as the traction device (14).

9. A method for motorized adjustment of a protective cover (2) of a machine, comprising a drive device according to any one of claims 1 to 8, wherein the protective cover is partially released by a counterweight (15), characterized in that: A flywheel (7) is connected between the motor (5) and the protective cover (2), and both raising and lowering of the protective cover (2) are performed with the flywheel (7) blocked.

10. The method according to claim 9, characterized in that As soon as the protective cover (2) is stopped by an obstacle during lowering, the flywheel (7) opens.

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