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DE-202026101281-U1 - Lifting device

DE202026101281U1DE 202026101281 U1DE202026101281 U1DE 202026101281U1DE-202026101281-U1

Abstract

Lifting device (10) for lifting a workpiece carrier (14) from a conveying means (16) and/or for lowering a workpiece carrier (14) onto a conveying means (16), wherein the lifting device (10) comprises: - a basic body (24), - an element (26) extendable from the base body (24), which can be extended and retracted from the base body (24) in a lifting direction (28), - an actuating unit (30) for the targeted extension and retraction of the extendable element (26), characterized in that the extendable element (26) has a first part (36) and a second part (38), wherein the first part (36) and the second part (38) are movable relative to each other in the stroke direction (28), and that the first part (36) and the second part (38) are coupled to each other via a spring element (40), so that the first part (36) and the second part (38) can move relative to each other under the influence of the spring element (40) when the extendable element (26) is subjected to a load in the stroke direction (28).

Assignees

  • WOERNER AUTOMATISIERUNGSTECHNIK GMBH

Dates

Publication Date
20260513
Application Date
20260306
Priority Date
20260306

Claims (16)

  1. Lifting device (10) for lifting a workpiece carrier (14) from a conveying means (16) and/or for lowering a workpiece carrier (14) onto a conveying means (16), wherein the lifting device (10) comprises: - a base body (24), - an element (26) extendable from the base body (24), which is extendable and retractable from the base body (24) in a lifting direction (28), - an actuating unit (30) for the controlled extension and retraction of the extendable element (26), characterized in that the extendable element (26) comprises a first part (36) and a second part (38), wherein the first part (36) and the second part (38) are movable relative to each other in the lifting direction (28), and that the first part (36) and the second part (38) are coupled to each other via a spring element (40), such that the first part (36) and the second part (38) can move relative to each other under the influence of the spring element (40) when the extendable element (26) is loaded in the stroke direction (28).
  2. Lifting device (10) according Claim 1 , characterized in that the first part (36) and the second part (38) are telescopically guided into one another.
  3. Lifting device (10) according Claim 2 , characterized in that the first part (36) and the second part (38) are each at least partially hollow cylindrical.
  4. Lifting device (10) according Claim 3 , characterized in that the first part (36) and the second part (38) form a common receiving space (46) for receiving the spring element (40).
  5. Lifting device (10) according to one of the preceding claims, characterized in that the spring element (40) is designed as a mechanical spring element.
  6. Lifting device (10) according Claim 5 , characterized in that the spring element (40) comprises a compression spring, in particular a helical spring.
  7. Lifting device (10) according to one of the preceding claims, characterized in that the first part (36) is coupled to or movable by the actuating unit (30) and that the second part (38) is provided for lifting the workpiece carrier (14).
  8. Lifting device (10) according to one of the preceding claims, characterized in that the first part (36) and the second part (38) are coupled to each other via a locking pin (52), wherein the locking pin (52) is guided in an elongated hole (54).
  9. Lifting device (10) according Claim 8 , characterized in that the locking pin (52) is mounted on the second part (38) and that the elongated hole (54) is formed in the first part (36).
  10. Lifting device (10) according Claim 8 or 9 , characterized in that the elongated hole (54) extends substantially parallel to the stroke direction (28).
  11. Lifting device (10) according to one of the preceding claims, characterized in that the actuating unit (30) is designed as an electric linear drive.
  12. Lifting device (10) according Claim 11 , characterized in that the electric linear drive has an electric motor (32) and a spindle drive with a spindle (34), wherein a translational movement of the extendable element (26) is generated by rotation of the spindle (34).
  13. Lifting device (10) according Claim 12 , characterized in that the electric motor (32) is designed as a servo motor or stepper motor.
  14. Lifting device (10) according to one of the preceding claims, characterized in that a displacement measuring system is provided for detecting the lifting position.
  15. Lifting device (10) according Claim 14 , characterized in that the displacement measuring system comprises a position sensor (66), in particular a Hall sensor, and a sensor element movable with the extendable element (26), in particular a magnetic element (62).
  16. Lifting device (10) according to one of the preceding claims, characterized in that the spring force of the spring element (40) is greater than a maximum permissible weight of a liftable workpiece carrier (14).

Description

The invention relates to a lifting device, in particular for lifting a workpiece carrier from a conveying means and/or for lowering a workpiece carrier onto a conveying means, in particular for use in automation technology for positioning a workpiece carrier. In automation technology, it is common practice to move workpiece carriers along a defined path using conveyors. Workpieces, goods, or similar objects can be transported using a workpiece carrier. In many cases, it is necessary to process a workpiece transported on the carrier at a machining station, which requires the secure and precise positioning of the workpiece carrier. For this purpose, the workpiece carrier is moved along the conveyor path by the conveyor, whereby the movement of the workpiece carrier can be interrupted at a defined position, for example, by a stopper, so that the workpiece carrier is stopped at the intended machining station. In this operating situation, however, the workpiece carrier remains in contact with the conveyor, so smooth and safe machining is not always guaranteed. For this reason, lifting devices, also known as index cylinders, are frequently used. These devices allow the workpiece carrier to be lifted from the conveyor to achieve stable and secure positioning. In the lifted position, a workpiece mounted on the carrier can, for example, be machined before the carrier is lowered back onto the conveyor and transported further along its path. A lifting device of the type mentioned above is, for example, made from the DE 10 2021 213 840 A1 known. There, a lifting device is described which, in particular, enables simplified and at the same time precise positioning of the lifting device relative to a conveying means. To lift the workpiece carrier, the lifting device has an extendable element which, in its lowered position, is located below and spaced apart from the workpiece carrier, ensuring free movement of the workpiece carrier along the conveyor. For a workpiece carrier to be lifted, it must be positioned above the lifting device so that the extendable element can engage in a designated receptacle on the workpiece carrier when extended. Typically, several lifting devices are used to lift a workpiece carrier, engaging different receptacles on the carrier to prevent, for example, the workpiece carrier from tipping. In certain applications, the workpiece carrier may be pressed against a so-called overreach during lifting. Such an overreach can be designed as a kind of counter-support or mechanical stop against which the workpiece carrier is pressed on the side opposite the lifting device. This allows for particularly precise positioning and fixing of the workpiece carrier, as the workpiece carrier is positioned and clamped between the lifting device and the overreach in the raised state. As soon as the workpiece carrier is pressed against such an overhang, its position is clearly defined and the workpiece carrier is fixed in place. With pneumatically operated lifting devices, this operating mode is relatively easy to implement, since the extendable element can be extended until the workpiece carrier rests against the overhang, with the extendable element being held in this position by continuous pressure. However, lifting devices are increasingly being used in which the extendable element is moved by means of an electric actuator, for example, an electric servo motor. With such electrically operated lifting devices, it can be problematic if the extendable element is moved against a fixed mechanical stop. Particularly when using stepper motors, the motor may lose steps if its movement is blocked by a mechanical stop. This can occur, for example, if the workpiece carrier is already pressed against the stop before the extendable element has reached its fully extended position. In such a case, the electric actuator would continue to attempt to extend the element, even though further movement of the workpiece carrier is prevented by the stop. This can lead to malfunctions or, in the long run, damage to the actuator. Based on this, the present invention aims to provide a lifting device of the type mentioned above in which reliable operation is enabled even when the workpiece carrier is pressed against a counter-stop, in particular against an overhang, during lifting. The aforementioned problem is solved by a lifting device for raising a workpiece carrier from a conveying means and/or for lowering a workpiece carrier onto a conveying means, wherein the lifting device comprises a base body, an element extendable from the base body which can be extended and retracted from the base body in a lifting direction, and an actuating unit for the targeted extension and retraction of the extendable element, wherein the extendable element comprises a first part and a second part, wherein the first part and the second part are movable relative to each other in the lifting direction, and wherein the first part and the second part are coupled