Title of Invention

DEVICE FOR ADJUSTING A CHECKING UNIT OF A PRESSER FOOT OF A SEWING OR EMBROIDERY MACHINE

Abstract The invention relates to a device for adjusting a checking unit of a presser foot (16) of a sewing or embroidery machine, the sewing or embroidery machine comprising atleast one embroidery head (4) which accommodates a plurality of components of the checking unit and a needle bar (17) moving the presser foot (16) in the direction of a needle plate (19) by the action of a spring (F) , the checking unit comprising atleast one cam disc (5 ) deflecting a cam lever (12) swivelably by means of a cam lever bearing (2), and a checking element (10), the checking unit catching the presser foot (16) before -it strikes a workpiece (18) to be processed by means of the checking element (10), the checking unit (2,5,10,12) controlling the movement of the checking (10) upto striking the workpiece (18), the checking element (10) being driven by a common drive (4a) together with the needle bar (17). The bearing (8) forming an axle (10a) of the checking element (10) is disposed axis-parallel to an axis of rotation of a rotating body (7), the rotating body (7) being rotationably mounted on the sewing or embroidery machine, the position of the bearing (8) being adjustable relative to the needle plate (19) by turning the rotating body (7).
Full Text FIELD OF-THE INVENTION
The invention concerns a device for adjusting the checking unit of a presser foot of a sewing and/or embroidery machine.
BACKGROUND OF THE INVENTION
An embroidery machine of this type with a checking unit for a pressex foot is known from DE 3117140. The*checking unit disclosed in DE 3117140 achieves a situation in which the presser foot no longer strikes the workpiece to be machined and therefore the needle plate.with the full force derived from the needle bar drive and transferred via the spring inserted in between, but is checked shortly before contact, a large part of the force residing in the movement of the presser foot being absorbed before the presser foot is released to perform the remaining movement with a certain time delay. The checking unit achieves a significant attenuation of the noise and protects the workpiece and/or the embroidery from damage caused by long term stress from the presser foot. The checking unit consists substantially of a control cam, which activates an angled lever, the one arm of which checks the presser foot, accelerated by a spring in the direction of the workpiece, via a checking component and releases the said foot with a time delay so that the presser foot is braked when it strikes the workpiece.
It is disadvantageous in the case of the checking unit known from DE 3117140 that, resulting from the rigid structure, the movement path of the presser foot is identical for different thicknesses of workpiece so that in the presence of relatively

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large workpiece thicknesses, the presser foot strikes the surface of the workpiece with too much force so that the advantages of the checking unit are reduced.
i A device is described in DE 19628524, with which the presser foot is moved into a safe position after the sewing process. No adjustment to material thicknesses is provided.
A very time-consuming and expensive way is described in DE " 4302094 in which the presser foot is moved via a separate drive motor thus permitting any desired movement paths and therefore adjustment to different thicknesses of material to be implemented. However, the additional drive requires a time-consuming synchronisation of the two drives for the needle bar and the presser foot.
DE 4324741 and DE 2938894 show checking units for presser foot attachments in which the movement path of the presser foot can be adjusted to the thickness of the material. It is disadvantageous in these units that they utilise complicated lever systems which have &n expensive structure and are prone to breakdowns. Increased demands.are imposed on the tolerances to be met because of the large number of moving parts and a relatively large amount of noise is created.
SUMMARY OF THE INVENTION
The object of the present invention is therefore to provide a checking unit for a presser foot of a sewing machine which is of a simple structure and permits an adjustment to a very wide range of workpiece thicknesses.
This object is achieved according to the invention.
,It is advantageous in the device according to the invention that the position of the bearing of the checking element, which works in direct combination with the presser foot, is changed manually

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or automatically and held and/or locked in a specific position. As a result, no additional elements are necessary which have to be arranged in the force transmission region between the checking element and the drive for the checking element. The adjustment of the position of the bearing of the checking element, which is preferably an angled lever, should be able to be moved to at least two positions or any desired location between two positions and/or should be able to be locked-
In a particular embodiment of the device, the bearing and/or the swivelling axle of the checking element can be swivelled around an axis, so that the position of the checking element alters relative to the needle plate depending on the angle set. To do /this/ the bearing of the checking element itself is mounted in a cylinder coaxial to the latter's axis, whereby the cylinder is mounted so that it can rotate around its axis on the sewing or embroidery machine.
If the cylinder is turned, the bearing which, for example may be a bolt, which is mounted so that it rotates in the cylinder coaxial to its axis, is moved around the axis, whereby the position of the bearing and/or the bearing bolt changes in respect of the needle plate. This permits an advantageous thickness adjustment of the presser foot to the workpiece or embroidery by simple means. The cylinder itself is can be locked in any desired angle positions or at specific engaging points by means of fixing screws or locking teeth which for example can be raised against a spring force.
The angle adjustment of the cylinder, mounted so that it can
rotate, which holds the bearing for the checking element, can be
performed automatically by means of a drive in a further
advantageous embodiment of the invention.
In a further embodiment, the bearing for the checking element is not mounted so that it can swivel around an axis but is able to

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be locked in various positions especially parallel to the needle bar e.g. in a longitudinal slot. Moving the bearing in the longitudinal slot may be undertaken manually or automatically by means of a drive as in the embodiments described above.
In a further form of the embodiments described above, the material thickness close to the presser foot is determined underneath the presser foot by means of a sensor and the position of the checking element is regulated to correspond automatically by means of a drive. This has the advantage of guaranteeing that even in the case of a workpiece which has different degrees of thickness at different points, the presser foot always strikes the workpiece in the bast possible way during the embroidery or sewing process.
BRIEF DESCRIPTION OF THE ACCOMPAMYING DRAWINGS Various embodiments of the invention are described in greater detail below on the basis of drawings.
Tfteje -ofo-ow:
Figure 1 a side view of an embroidery head with a
checking unit according to the invention;
Figures 2a + 2b: different settings for the position of the
checking element;
Figure 3 an exploded representation of the parts of an
embroidery head relevant to the checking unit;
Figure 4 an exploded representation of a checking unit
according to the invention with an electric drive to adjust the bearing of the checking element automatically;
Figures 5a + 5b: Checking unit with distance sensor

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Figure 6: A multi-head embroidery machine with a
central drive for the device according to the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION Figure 1 shows a side view of the principal parts of the
checking unit. The embroidery head 4, on which the parts of the checking unit and the needle bar guide and the needle bar drive /are arranged, is shown as a dashed line. At least one cam disc 5, which deflects a cam lever 12, which is mounted so that it can swivel by means of the cam lever bearing 2, is arranged on a shaft 4a, which passes through and engages with the one embroidery head 4, or also further embroidery heads, if the shaft 4a is rotated. An angled lever 10, which forms the checking element and is mounted rotatably so that it can swivel around the axle 10a is deflected via a connecting rod 11. The free end of the one angle arm of the angled lever 10 supports a roller 9 which checks and releases the presser foot 16, accelerated downwards by the spring F, according to the movement of the angled lever 10, which is specified by the design of the guide curve of the cam disc 5. The needle bar 17 is held by a guide 20 and is driven via the needle bar drive 15, which is not shown in greater detail in figure 1. Like the angled lever 10, the needle bar drive 15 can be driven by the shaft 4a.
As is shown by figures 2a and 2b, by turning an eccentric bolt 7, the position of the axle 10a of the angled lever 10 can be adjusted relative to the needle plate 19 and the embroidery material or workpiece 18. The eccentric bolt 7 is mounted in a bearing bush 8 for this and can be locked in any desired angle positions by means of a fixing screw 6 (figure 3).
In addition to the adjustment of the height of the angled lever 10, it is possible to lock the swivelling axle of the cam lever 12 in different positions. The device has a bearing pin 2a for this purpose, which is arranged eccentrically to an axis of

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rotation of the component 2. The component 2 rests in a bore with its cylindrical component 2b in a bore 3a of a base plate 3 and is mounted in this so that it can rotate. The bearing pin 2a engages with the bore 3a and serves as a bearing for the cam lever 12. The component 2 can be locked in any desired angle positions (arrows) in respect of the base plate 3 by means of a plate 1 and a fixing screw la. By rotating the component 2, the bearing pin 2a is swivelled around the axis of rotation of the component 2 and therefore changes its position.
A roller 14 or a ball bearing, which rests in the guide curve of the cam disc 5 and follows the latter when the cam disc 5 is rotated, is mounted on the one arm of the cam lever 12 on a pin 13. The other arm and therefore the angled lever 12 is swivelled correspondingly.
Figure 4 shows a further embodiment of the device according to the invention, the structure of the device being substantially similar to the embodiment according to figure 3, whereby, however, the eccentric bolt 7 is replaced by an eccentric bolt
21 which has teeth {toothed wheel) on its one end which are
connected to a servo-motor 22 via a toothed belt 23. The
eccentric bolt 21, and with it the bearing 10a of the angled
lever 10, are automatically adjusted by means of the servo-motor
22 and held in position.
Figures 5a and 5b show a further embodiment of the device according to figure 4, which possesses an additional sensor 24, which measures the thickness of the material and/or the distance of the surface of the material 18 from the sensor 24, The eccentric bolt 21 is turned corresponding to the sensor data, by means of the actuating drive 22, not shown, the swivelling axle 10a of the angled, lever 10 being swivelled relative to the needle plate 19. The connecting rod 11 serves to compensate for the relative movements between the angled lever 10 and the cam

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lever 12 during the adjustment either of the cam lever 12 or the angled lever 10 by means of the respective adjusting device.
In embodiments/ which are not shown, the bearing and/or the swivelling axle of the angled lever is not mounted so that it can swivel around an axis but is moved in a linear manner, manually or by means of a drive, and locked in the position required. It is also feasible that the bearing and/or the swivelling axle can be moved along any desired paths and locked.
Figure 6 shows a multi-headed embroidery machine with a central drive 24, which drives eccentric bolts 21 of the individual embroidery heads 4 of the machine via a shaft 27 and toothed belts 23, whereby it is possible to make a simultaneous height adjustment of the presser foot attachments of all the embroidery heads simultaneously. As all the embroidery heads usually embroider identical embroidery designs, it is sufficient to determine the distance between the surface of the embroidery and the needle plate on just one embroidery head or embroidery design in order to undertake the height adjustments for all the embroidery heads simultaneously on the basis of the distance determined. In an embodiment, which is not shown, couplings are provided between the shaft 27 and the eccentric bolt 21 so that the height adjustment of specific embroidery heads 4 can be switched on or off optionally, depending on the requirement. Thus in multi-headed embroidery machines, e.g. as a consequence of the size of the embroidery design, often only certain embroidery heads are required such as e.g. every second, third etc. embroidery head. The other embroidery heads are disconnected from the main drive shaft. In this case the couplings can be used to switch off the presser foot attachments of the embroidery heads which are not required.

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We claim;
1- Device -for adjusting a checking unit of a presser foot (16) of a sewing or embroidery machine, the sewing or embroidery machine comprising at least one embroidery head which accommodates a plurality of components of the checking unit and a needle bar moving the presser foot U6) in the direction of a needle plate by the action of a spring before it strikes a workpiece to toe processed by means of the checking element characterised in that a bearing (8) forming an axle (10a) of the checking element tis of rotation of a "rotating body , the rotating body 2. Device as claimed in claim 1, wherein the rotating body i7> can be locked in a specific position hy means of a locking element (6), in particular a fixing o&cr-e\*t*

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3. Device as claimed in claim 2, wherein the rotating body
locked in at least one position.
4. Device as claimed in clsim X to 4, wherein the checking
element (10) is an angled lever.
5. . Device as claimed in claim 1 or 4, wherein one of the
bearing (S) and the axle (10a) can be locked in at least two
posi tions relative to the needle plate (19).
6- Device as claimed in any one of the preceding claims,
wherein the movement of the checking element (10) is controlled
by the control cam (5 ) driven dependent on a needle bar drive
(15) .
7. Device as claimed in claim 6, wherein a compensation element, especially a connecting rod (11) is inserted between the cam lever (12) moved by the control cam (5) and the checking element (10)
B- Device as claimed in claim 7, wherein the cam lever (12) is mounted around an axle (2a) on the sewing machine so that it can swivel, the position of the axle (2a) being adjustable

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relative to an axle by means of an adjusting device , especially a locking screw.
9. Device as claimed in any one of the preceding claims, wherein the thickness of a worScpiece close to at least one presspr foot (16) is determined by means of at least one sensor (24) and, wherein the drive (22) " sets or regulates the position required for the checking element 10- Device as claimed in claim 13( wherein the sensor U- Device as claimed in any one of the preceding claims, wherein the height adjustment of the presser foot .
12, Device as claimed in claim li, wherein a common shaft (27> connects the drive (24) to the means (24) of adjustment to move or advance the bearing
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13. Device as claimed in claim 12 wherein at least one
coup I ing is provided between the shsft and one of the
bearing
14. Device for adjusting a cheeking unit of s presser foot
(16) of a sewing or embroidery machine as claimed in claim 1, the
position of the bearing of the checking element of the checking unit being alterable relative fco the needle piste characterised in that a control determines the thickness of the workpiece close to at least one presser foot and, using the- drive (22) , sets or regulates the required position for the checking element- The invention relates to a device for adjusting a checking unit of a presser foot (16) of a sewing or embroidery machine, the sewing or embroidery machine comprising atleast one embroidery head (4) which accommodates a plurality of components of the checking unit and a needle bar (17) moving the presser foot (16) in the direction of a needle plate (19) by the action of a spring (F) , the checking unit comprising atleast one cam disc (5 ) deflecting a cam lever (12) swivelably by means of a cam lever bearing (2), and a checking element (10), the checking unit catching the presser foot (16) before -it strikes a workpiece (18) to be processed by means of the checking element (10), the checking unit (2,5,10,12) controlling the movement of the checking (10) upto striking the workpiece (18), the checking element (10) being driven by a common drive (4a) together with the needle bar (17). The bearing (8) forming an axle (10a) of the checking element (10) is disposed axis-parallel to an axis of rotation of a rotating body (7), the rotating body (7) being rotationably mounted on the sewing or embroidery machine, the position of the bearing (8) being adjustable relative to the needle plate (19) by turning the rotating body (7).

Documents:


Patent Number 201694
Indian Patent Application Number IN/PCT/2001/00975/KOL
PG Journal Number 08/2007
Publication Date 23-Feb-2007
Grant Date 23-Feb-2007
Date of Filing 19-Sep-2001
Name of Patentee ZSK STICKMASCHINEN GMBH
Applicant Address MAGDEBURGER STRASSE 38-40, D-47800 KREFELD- GARTENSTADT, GERMANY
Inventors:
# Inventor's Name Inventor's Address
1 HEIDTMANN THOMAS IN DER SILBERT 28 D-47877 WILLICH, GERMANY
2 KIRCH BERND KEMPENER STR. 29, D-47839 KRAFELD, GERMANY
PCT International Classification Number D 05B 29/02;
PCT International Application Number PCT/EP00/01280
PCT International Filing date 2000-02-17
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 199 18 169.1 1999-04-21 Germany