Method for embroidering three-dimensional workpieces

Abstract

A method for embroidering three-dimensional workpieces (2) uses an embroidery machine (100) with at least one embroidery head (101) for embroidering and at least one embroidery frame (1) for positioning the workpiece (2). The workpiece (2) is moved by means of the embroidery frame (1) by at least two angles (Θ, μ, ω) in relation to at least two axes (X, Y, Z), which are in relation to the movement axis of the embroidery head (101) positioned to introduce at least one stitch of embroidery into the workpiece (2).

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of German Patent Application DE 10 2023 103 349.2, filed on Feb. 13, 2023, which is incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a method for embroidering three-dimensional workpieces.

BACKGROUND

Embroidery machines that can embroider not only flat structures, but also curved structures, are generally known. Such curved structures are often half-round and are used as headgear in the form of caps.

Sewing robots that can process curved surfaces are also known. Post bed sewing machines used to sew hollow objects are also generally known.

The full-surface embroidery of a curved three-dimensional structure using an inexpensive articulation mechanism is currently not possible with an embroidery machine. Instead, for example, in the case of a cap, only a partial area can be embroidered. Such a partial area corresponds to a rectangular section of a cylinder surface. The movement for embroidering such a section of a cylinder surface with respect to the needle is derived from an X and Y direction of an embroidery frame that is only partially present. This is done in such a way that the movement in the depth direction Y of the pantograph of the embroidery machine is maintained. In contrast, the lateral movement X of the pantograph is converted into a rotary movement, for example by means of a cable pull. This makes it possible to embroider a portion of a cap, with this portion being determined by the way the cap is clamped before the embroidery process. The design to be embroidered on this section is provided to the embroidery machine control in the form of stitch data. This stitch data is a sequence of data in the form of a triple consisting of an adjustment path in the X direction, an adjustment path in the Y direction and the information to create a stitch at the position reached after the adjustment of the cap to be embroidered. A large number of these triples in an orderly sequence one after the other create the desired design on the cap. Since the section to be embroidered is part of a cylinder surface, its development can be viewed as a flat rectangular element. Therefore, to generate the stitch data triples, a design is simply artistically created in a rectangular base area, since the transfer to the section of the cylinder surface is inherent through the use of the previously mentioned cable pull mechanism.

If several partial surfaces of such a cap are to be embroidered, this is only possible by laboriously re-clamping the cap so that several cylindrical sections can be embroidered one after the other.

SUMMARY

The present disclosure eliminates the aforementioned disadvantages. Embroidering a curved workpiece is no longer restricted to a rectangular section of a cylinder surface. Rather, an almost full-surface embroidery of the surface of a workpiece can be advantageously achieved. The term workpiece is used in the further description to reflect that the disclosed method and apparatus are not limited to the embroidery of caps, but can be used with a broad range of objects.

The method for embroidering three-dimensional workpieces is carried out using an embroidery machine which comprises at least one embroidery head for embroidering and at least one embroidery frame for positioning the workpiece.

The workpiece is positioned by pivoting the embroidery frame about at least two angles with respect to at least two axes which are non-parallel to the axis of movement of the embroidery head, in order to introduce at least one stitch of embroidery into the workpiece. The at least two axes preferably include a lateral axis and a longitudinal axis, with the embroidery head moving in a vertical axis. The lateral axis preferably intersects the vertical axis. The longitudinal axis preferably intersects the vertical axis. The lateral axis, the longitudinal axis, and the vertical axis may intersect in a point of origin.

This design enables the embroidery of a workpiece, for example a cap, in one clamping over almost the entire surface of the workpiece. The embroidery frame includes or is operatively connected to drives that enable the pivoting motion. The workpiece can preferably be rotated about the vertical axis.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a post bed embroidery machine with an embroidery frame for full-surface embroidering.

FIG. 2 shows an embroidery frame for full-surface embroidering with the axes and angles of rotation.

FIG. 3 shows an embroidery frame for full-surface embroidering with its individual elements.

FIG. 4 shows an embroidery frame for full-surface embroidering with a clamped workpiece in form of a cap.

FIG. 5 shows an embroidery frame for full-surface embroidering with a clamped cap and an exemplary embroidery position set according to the rotation angle Θ=+45°, μ=0°, and ω=0°.

FIG. 6 shows the embroidery frame as in FIG. 5 in a second embroidery position with Θ=0°, μ=−45°, and ω=0°.

FIG. 7 shows the embroidery frame as in FIG. 5 in a second embroidery position with Θ=+30°, μ=+30°, and ω=180°.

DETAILED DESCRIPTION

FIGS. 1-7 show an embroidery frame 1 for positioning a workpiece 2. The workpiece 2 is clamped to the embroidery frame 1. The embroidery frame 1 includes or is operatively connected to at least one drive 3, 4, 5 for the driven pivoting or rotating of the workpiece 2 by at least two angles Θ, μ, ω.

An embroidery machine 100 for embroidering the workpiece comprises at least one embroidery head 101 for embroidering and at least one embroidery frame 1 for positioning the workpiece 2.

In a particularly advantageous embodiment, the embroidery machine 100 can also include several embroidery frames 1, with each of these several embroidery frames 1 being assigned at least one embroidery head 101.

The embroidery machine 100 is provided with an articulation mechanism for the curved three-dimensional workpiece 2, which allows the curved workpiece 2 to be tilted about the two independent but limited angles Θ and μ and rotated about the infinite angle of rotation ω. This arrangement makes it possible to bring almost any position of the surface of the curved workpiece 2 below the needle position.

FIG. 1 shows a post bed embroidery machine 100 with a control. The post bed embroidery machine 100 is equipped with an embroidery head 101 which is equipped with several needles, with only one of the several needles within the embroidery head 101 being connected to a drive mechanism of the embroidery head at a time. By moving the embroidery head 101 laterally, it is possible to select another one of the several needles, so that the selected needle is driven by the drive mechanism of the embroidery head 101. Since the different needles can be equipped with different colored threads, for example, it is possible to create embroidered areas of different colors in order to achieve the artistic impression of the embroidery.

FIG. 3 shows the embroidery frame 1 for full-surface embroidery as well as several drives 3, 4, 5 of the embroidery frame 1.

In FIG. 2, the embroidery frame 1 for full-surface embroidering and the drives 3, 4, 5 of the embroidery frame 1 are shown in detail in relation to the embroidery head 101. For orientation purposes, the Cartesian axes X, Y and Z are shown. Here, the pitch angle Θ denotes a rotation about the longitudinal X-axis, the roll angle μ denotes a rotation about the lateral Y-axis and the yaw angle ω denotes a rotation about the vertical Z-axis. The pitch angle Θ and roll angle μ can have both positive and negative values, but are limited due to the mechanical arrangement. For example, Θ and μ may each be limited to a pivot angle in the range between −45° and +45°. The yaw angle ω can also assume positive and negative values and is not inherently limited by the mechanical arrangement.

FIG. 3 shows the embroidery frame 1 for full-surface embroidering in relation to at least one post 102. The post 102 accommodates a bobbin and bobbin case, which holds a bottom thread. The embroidery frame 1 is preferably gimballed within the post 102. The gimbal suspension allows the pivoting shown in FIG. 2 by the pitch angle Θ about the longitudinal X-axis and by the roll angle μ about the lateral Y-axis as previously described. To carry out the pivoting around the X-axis, a pitch drive 3 is used to adjust the pitch angle Θ. Executing a positive adjustment of the pitch drive 3 results in the front area of the embroidery frame 1 pivoting up by the positive pitch angle Θ and the rear area of the embroidery frame 1 pivoting downwards to the same extent. Accordingly, the pivoting directions behave in reverse when the drive 3 is adjusted negatively.

Independently thereof, a roll drive 4 is used to adjust the roll angle μ around the lateral Y-axis. Executing a positive adjustment of the drive 4 results in the right area of the embroidery frame 1 pivoting up by the positive roll angle μ and the left area of the embroidery frame 1 pivoting downwards to the same extent. Accordingly, the pivoting directions behave in reverse when the drive 4 is adjusted negatively.

Since the pitch drive 3 for the pitch angle Θ and the roll drive 4 for the roll angle μ are advantageously orthogonal to one another, it is possible to bring the entire surface of the clamped workpiece 2 under the needle positions for carrying out embroidery. The orthogonal arrangement of the drives 3, 4 to one another is one of several possible embodiments.

FIG. 3 shows further elements of the embroidery frame 1 according to the invention for full-surface embroidery. A longitudinal strut 8 connects the fixed inner ring 7 along the longitudinal X-axis with the gimbal suspension within the post 102. Accordingly, a lateral strut 9 connects the fixed inner ring 7 along the Y-axis with the gimbal suspension within the post 102.

A rotatable outer holder 6 serves to receive the workpiece 2—as shown in FIG. 4—during embroidering and to hold it at the lower edge. The rotatable outer holder 6 is mounted on the fixed inner ring 7 in such a way that rotation of the outer holder 6 around the inner fixed ring 7 by the yaw angle ω is possible. This can be achieved, for example, by incorporating a circumferential groove on the inside of the outer holder 6 and attaching webs which engage in the circumferential groove of the holder 6 on the outside of the fixed ring 7. A yaw drive 5 is used to realize the rotation of the outer holder 6 by the yaw angle ω around the Z axis. Drive energy of the yaw drive 5 can be transmitted to the outer holder 6, for example, by incorporating a gear ring all around the inside of the outer holder 6 and a driven gear wheel from the yaw drive 5 engaging in this gear ring and thus transmitting the rotational movement. This arrangement allows continuous, unrestricted rotation of the workpiece 2 about the vertical Z-axis. The yaw angle of rotation ω can assume any positive or negative values.

By implementing three independent angle adjustments for pitch Θ, roll μ, and yaw ω, the embroidery of the workpiece is advantageously possible in one clamping and over almost the entire surface of the workpiece 2 as well as all around.

FIGS. 5, 6 and 7 each show different positions of the workpiece 2 in relation to the needle position. This makes it possible to embroider almost the entire surface of a three-dimensional workpiece 2 using the articulation mechanism described here.

According to the method, the respective new position of the workpiece 2 is particularly advantageously determined from predetermined coordinate triplets and the at least one embroidery frame 1 is controlled by means of the drives 3, 4, 5 in such a way that the positioning of the workpiece 2 is carried out around the pitch angle Θ, the roll angle μ, and the yaw angle ω.

In addition, it can be advantageous for the positioning of the workpiece 2 around the pitch angle Θ, the roll angle μ, and the yaw angle ω to be calculated and carried out step by step from continuously transferred coordinates for each stitch of the embroidery.

The articulation mechanism is preferably controlled by the drives (drive units) 3, 4 and 5. These can be powered by an electric motor or any other drive energy.

To control the correct movement of the drives 3, 4, 5, a control is preferably provided which determines the new position of the workpiece 2 from predetermined coordinate triples and sets it using the drives 3, 4, 5. By synchronizing the positioning of the workpiece 2 with the drive mechanism of the embroidery head 101, it is achieved that the needle only penetrates into the workpiece 2 after it has been positioned and then carries out a stitch of embroidery. By continuously adjusting the workpiece 2 and introducing further stitches based on the evaluation of the successive coordinate triples, the entire surface of the workpiece 2 is embroidered.

LIST OF REFERENCE NUMBERS

• • 1 Embroidery frame for full-surface embroidering with drives
  • 2 Workpiece (cap)
  • 3 Pitch drive for pitch angle adjustment Θ
  • 4 Roll drive for roll angle adjustment μ
  • 5 Yaw drive for yaw angle adjustment ω
  • 6 Rotatable outer ring to receive the workpiece
  • 7 Fixed inner ring
  • 8 Longitudinal strut in X-direction
  • 9 Lateral strut in Y-direction
  • 100 Post bed embroidery machine with control
  • 101 Embroidery head
  • 102 Post for holding the bobbin

Claims

1. A method for embroidering a workpiece using an embroidery machine that comprises an embroidery head for embroidering and an embroidery frame for positioning the workpiece, comprising: positioning the workpiece by pivoting the embroidery frame about at least two angles around at least two axes which are arranged non-parallel in relation to an axis of movement of the embroidery head; andintroducing a stitch of an embroidery into the workpiece.

2. The method according to claim 1, wherein positioning the workpiece includes pivoting the workpiece about a lateral axis,pivoting the workpiece about a longitudinal axis, androtating the workpiece in a vertical axis.

3. An embroidery frame for positioning a workpiece relative to an embroidery head in an embroidery machine, comprising: at least one drive for pivoting the workpiece about at least two angles.

4. The embroidery machine as in claim 3, further comprising at least one embroidery head for embroidering, andat least one embroidery frame for positioning the workpiece, the at least one drive being operatively connected to the at least one embroidery frame.

5. The embroidery machine according to claim 4, further comprising a plurality of embroidery frames, andat least one embroidery head assigned to each of the embroidery frames.

6. The embroidery machine according to claim 4, wherein the embroidery machine is a post bed embroidery machine and comprises at least one post.

7. A method for controlling an embroidery machine having an embroidery frame for pivoting a workpiece by at least two angles, comprising: pivoting the embroidery frame about two spatial axes to place the workpiece into a new position by controlling drives that are operatively connected to the embroidery frame.

8. The method as in claim 7, further comprising determining the new position of the workpiece based on predetermined coordinate triplets.

9. The method as in claim 7, further comprising calculating the new position of the workpiece stepwise from continuously transferred coordinates for each stitch of an embroidery.