DE19825784A1 - Drive mechanism for the thread guide lever in a multi-head embroidery machine - Google Patents

Abstract

The mechanism to operate the thread guide lever (1), at a multi-head embroidery machine, has a shaft (9) with a cam disk (8) to operate levers (4,6) acting on the thread guide lever (1). A cam follower (7), to transmit the cam movements to the guide lever through the drive levers, can be moved away from the cam groove (8a) over a total or part angular range. A setting unit swings and/or holds the cam follower (7) in an inactive position. The cam follower (7) is under a movement pressure towards the cam disk (8) so that, when released from the inactive position, it is moved towards the cam disk (8) and engages the cam groove (8a) immediately on or after shaft (9) rotation. The deflection angle of the linkage levers (4,6) into the rest position is at least equal to the deflection angle of the levers (4,6) through the cam disk (8). The cam follower (7) is a bolt or shaped projection or rotating roller, on a rotating axis parallel to the cam disk (8) axis. The setting unit is a spring and a limit (8b), where the displaced cam follower (7) is held against the limit (8b). The limit (8b) is a shaped tube or sleeve projection at the cam disk (8), as an inactive curve for the follower (7). The inner radius of the limit (8b) equals the max. radial gap between the rotary axis and the outer groove wall of the cam disk (8), and the setting spring presses the cam follower (7) against the inner wall of the projection (8b). An additional holder is fitted at the side of the linkage levers (4,6) away from the cam disk (8), as a projection or bolt and especially a rotating body, to be held against the limit by the setting spring. The limit can also be a projection fitted to the shaft, where the spring holds the cam follower against its inner wall. The inner radius of the limit projection is set so that the cam follower has a simple axial sliding movement back to the cam disk and/or is moved into the cam groove by the shaft rotation. The cam follower (7) and the holder are on the same axis, as a bolt through the lever. An additional cam disk can be fitted to the shaft (9), with the lever linkage (4,6) between them to engage either the cam groove (8a) of the first disk (8) or the cam groove of the second disk. Both cam disks have projections as limits. The end of the lever has a U-shape, with followers at the inner sides of the legs for selective engagement with the cam disk or sliding block on the shaft (9). A limit projection is at one of the two flat sides of the sliding block. The shapes of the cam grooves, or guide surfaces, give different movement profiles to the thread guide lever (1). The assembly has a drive, to move the linkage levers (4,6) or cam follower with its holder in an axial direction to and from the shaft (9). The movement is through an eccentric, lifting magnet or an electromagnetic drive. The cam groove can be replaced by a sliding block with a number of overlaid guide surfaces.

Description

The present invention relates to a device for drove a thread guide lever in an embroidery machine at least one embroidery head, with each embroidery head at least has at least one thread guide lever, and at most only one a thread guide lever of an embroidery head via a gear can be driven by a shaft, the shaft being the transmission be driven by at least one embroidery head, and the gear be by a grooved cam on the shaft and gebil a lever rotatably mounted about an axis det, the lever is the thread guide lever drives non-positively and / or positively, and one on the lever ches engagement means for driving the thread guide lever can be brought into engagement in the groove of the groove cam.

For embroidery machines, especially multi-head embroidery machines become the needles of the embroidery heads arranged side by side mostly driven by a shaft. The Embroidery heads each have several needles arranged side by side have, each by the method of the needles ei ne of the needles can be connected to the shaft via a gear is. Each needle is assigned a thread guide lever  arranges. The thread guide levers are also used in the Ver move the embroidery heads one after the other optionally over a white teres gearbox connected to a drive shaft.

EP 0471187 describes a camshaft gear for threads guide lever known. A spring is used the lever pivoting the thread guide lever with its egg NEN end against one located on the drive shaft Cams pressed. When turning the shaft, the Cam the lever against the spring force adjusted, causing the thread guide lever is deflected. To switch off the Thread guide lever is by means of a company the guide lever is pivoted into a position in which the No longer lever one end against the cam presses and are therefore no longer deflected by it can.

DE 39 23 419 is a drive for a thread guide lever known, in which the thread guide lever is rotatable is mounted on an axle and has a gear segment, which is arranged with one at one end of a lever Gear segment interacts, the lever also is rotatably mounted on a shaft. This wave is going by another He firmly connected to this wave with one end optionally in the groove of one Groove cam disc or link engages, rotated so that by turning the axis of the levers with the gear wheel ment is pivoted, which is due to the force conclusion of the engagement of the gear segments of the thread guide lever is pivoted up and down. The switch off or uncoupling from that driving the grooved cam Wave happens by means of a bolt that passes through a Ma gnet is optionally moved into the groove of the groove cam, which keeps the thread guide lever in sync with the groove curves disc is moved up and down. Disengaging or engaging  can only be done when the shaft is stationary. Is the bolt moved out of the groove by means of the magnet Thread guide lever decoupled from the driving shaft. When the bolt is moved out, the one carrying the bolt becomes Lever fixed, causing the thread guide lever in its Position lingers and not by its own weight pivoted down force.

A disadvantage of the known prior art is that the solution according to DE 39 23 419 the drive shaft when Disengaging or engaging must be stopped. Due to the necessary exactness of the adjustment of the thread guide bels are only small tolerances regarding the width of the Groove and the thickness of the engaging bolt tolerable. This makes it relatively problematic for the bolt Always insert the clutch exactly into the groove. Also the decoupling is only in a certain position the drive shaft possible.

A disadvantage of the device according to EP 0471187 is that although the thread guide lever in any position of the shaft can be uncoupled from this, but that always a Spring force is needed which is one end of the thread lever pivoting lever against the cam pressurized. To a si at high revs Ensuring a more secure fit on the cam is one very high spring force necessary, which means high friction te and associated increased wear in purchase must be taken and in addition an increased drive torque is necessary. To uncouple one, the big one Contact pressure overcoming force can be applied, whereby the respective facility is sized accordingly must become.  

The object of the invention is therefore to provide a drive for provide the guide lever, in which a decoupling the thread guide lever from the shaft when the shaft is rotating or at different angular positions of the stationary Shaft with little effort is possible and the thread guide lever after the uncoupling process in a certain Position remains.

This object is achieved with a device solved the features of claim 1. More beneficial Refinements result from the characteristics of the Un claims 2 to 14.

The device according to the invention advantageously uses the Grooved cam of the device according to DE 39 23 419 and also enables the thread guide to be uncoupled bels in any position of the drive shaft. The Coupling and uncoupling is also possible at low speeds feasible from approx. 100 rpm. The switching times must not be exact, but can be in an angular range lie, which can vary depending on the speed and curve shape.

Another object of the present invention is that to further develop the device according to the invention, that the thread guide lever two different from each other che movements with one revolution of the drive shaft can perform.

According to the invention this object is achieved in that In addition to the first grooved cam, another grooved cam is attached to the shaft in such a way that the He optionally driven by one of the two groove curves becomes. It is also conceivable that in a groove cam two groove curves are arranged, either an on gripping means optionally in one of the two groove curves engages, or two engaging elements are provided, which  are each assigned to a groove curve. The shape of the groove Curves are advantageously shaped differently, so that each de grooved cam own movement of the company the guide lever. This is advantageous in the Processing of special embroidery threads and / or embroidery materials to get a better embroidery quality and the company to minimize the frequency of breakage. By the use of two groove curves, it is also possible to have two identical movements to implement processes that are relative to the wave movement are time-shifted to each other.

Instead of a groove curve, one can befe on the shaft Stigt backdrop are used, then a spring that Means of engagement of the lever and, if present, the holding device tel, radially outwards against the link guide hits. By axially moving the lever ver advantageously swings one of the link guides the engaging or holding means and with it the lever.

In all embodiments, each can instead of the lever any transmission element can be used.

Exemplary embodiments of the invention are described below hand explained in more detail by drawings.

Show it:

Fig. 1 is a cross-sectional view through a drive device for a thread guide lever;

Fig. 2 and Fig. 3 first embodiment with a grooved disc for a thread take-up curve and a rest position;

. Figs. 4 to 6 second embodiment with two cam grooves slices for two different motion paths of the yarn guide lever, and a rest position;

Fig. 7 and Fig. 8 third embodiment with two groove curves for a movement path of the thread guide lever, and a rest position;

Fig. 9 fourth embodiment with two groove curves for two movement paths of the thread guide lever, but without a resting position;

Fig. 10 and Fig. 11 fifth embodiment with a groove cam disc for a movement path of the thread guide lever, and a rest position;

Fig. 12 to Fig. 15 sixth embodiment, with a backdrop with several guide surfaces for at least two different paths of movement of the thread guide lever, as well as a resting position.

Fig. 1 shows a cross-sectional view through a thread guide lever drive. On the shaft 9 a Nutkur vensscheibe 8 is attached, which rotates with the shaft 9 . The groove cam 8 has a groove curve 8 a and a zy cylindrical projection 8 b. If the cam roller 7 engages in the groove 8 a, the lever 4 , 6 , which is rotatably mounted on the shaft 5 , is deflected during the rotation of the shaft 9 and the groove cam disc 8 and drives with its toothed end the thread guide lever 1 , which is rigidly fixed with a toothed hub 2 and is rotatably mounted on the shaft 3 . By lever 4 , 6 , which serves as a transmission element, the rotational movement of the shaft is translated into a back and forth movement of the thread guide lever 1 . It is conceivable that instead of the two-armed lever 4 , 6 , a one-armed lever or another transmission element is also used.

As can be seen from FIGS. 2 and 3, the lever 4 is clamped on the shaft 5 . The lever 6 can be moved back and forth by means of the lifting magnet 15 . Instead of the lifting magnet 15 , any other type of drive that allows a back and forth movement can be used. The solenoid 15 has a driver 14 which is fixed on the armature 15 a and surrounds the projection 6 a of the lever 6 such that it can move it back and forth. The lifting magnet 15 overcomes the frictional force generated by the feather key 13 during the displacement. At one end of the lever 6 , the cam roller 7 , which serves as an engagement means, BEFE Stigt. By means of the torsion spring 12 , the cam roller 7 ge against the outer wall of the groove curve 8 a or against the cylindri cal inner surface of the cylindrical projection 8 b constantly pressurized. The spring force of the torsion spring 12 need not be large, since it only has to be ensured that the thread guide lever 1 is not pivoted downward by the resulting weight forces of the moving parts during the switched-off phase.

Fig. 2 shows the device in the position in which the thread guide lever 1 is moved back and forth by the groove curve 8 , since the cam roller 7 engages in the groove curve 8 a of the groove cam 8 .

Fig. 3 shows the position in which the cam roller 7 by means of the solenoid 15 from the groove curve 8 a was ren out and now only on the circular cylindrical inner surface of the cylindrical projection 8 b be due to the torsion spring 12 . Even while the grooved cam 8 rotates, the deflection position of the guide lever or lever 4 , 6 is not changed.

As can be seen from Fig. 1, in a large win kelbereich the groove curve 8 a circular, the groove outer surface in this area is aligned with the inner wall of the cylindrical projection 8 b. If the cam roller 7 is in this area, the roller can be moved from the rest position into the groove curve 8 a by means of the lifting magnet 15 . Extending the cam roller 7 from the groove curve 8 a is possible at low speeds in the entire angular range. If the thread guide lever is pivoted downwards by the deflection by means of the groove curve 8 a, and at the same time the lever 6 is adjusted into the rest position by means of the lifting magnet 15 , the cam roller 7 is moved away from the shaft 9 or by the spring force of the torsion spring 12 Thread guide lever 1 pivots upwards until the cam roller 7 strikes the cylindrical pre jump 8 b.

Figs. 5 to 6 show a further embodiment of the present invention in which two Nutkurvenscheiben 8, are mounted on the shaft 9 16. At the end of the lever 6 , two cam rollers 7 , 7 a are attached, the cam roller 7 cooperating with the groove cam 8 and the cam roller 7 a cooperating with the groove cam 16 or the groove curve 16 a. The lever 6 is driven by means of the same drive as in the device according to FIGS. 1 to 3, only with the difference that now more three positions in the axial direction by means of the stroke length 15 can be predetermined, so that the cam roller 7 can optionally be in the groove curve 8 a of the groove cam 8 engages or bears on the cylindrical inner surface of the circular pre jump 8 b ( FIG. 5) or the cam roller 7 a in the groove curve 16 a of the groove cam 16 is engaged ( FIG. 5). The groove curves 8 a and 16 a differ from one another, so that by rotating the shaft 9 of the thread guide lever 1 depending on which groove curve 8 a, 16 a it is driven, traverses different trajectories. If the solenoid 15 moves from the rest position, as shown in Fig. 5, in the direction of one of the two groove cam disks 8 , 16 , it may happen that the thread roller 7 , 7 a not in the respective groove 8 a, 16 a can intervene. In this case, the cam roller 7 , 7 a is pressurized against the lateral end face of the grooved cam 8 , 16 . As soon as by the rotation of the shaft 9 and thus the grooved cam 8 , 16, the respective groove curve 8 a, 16 a the engagement of the respective cam roller 7 , 7 a ge, by the force of the lifting magnet 15, the Kur venrolle 7 , 7 a is completely in the respective groove curve 8 a, 16 a introduced. Once the respective cam roller 7, 7 a in the respective cam groove 8, 16 a engages a, the yarn guide lever 1 corresponding to the respective curve shape of the groove 8 a, 16 a pivoted.

FIGS. 7 and 8 show a further embodiment of the device according to the invention, ben wherein two Nutkurvenschei 19 and 18 of the lever 6 on both sides on the shaft 9 are arranged, wherein the openings of the cam grooves 18 a and 19 a respectively to the lever 6 or the respective cam roller 7 , 7 a are open. The rest position is realized in this exemplary embodiment from the groove cam 18 with its circular groove curve 18 a. If the cam roller 7 is in the groove curve 19 a, the thread guide lever is moved up and down. If the lever 6 is pushed axially by the lifting magnet 15 into the position according to FIG. 8, the cam roller 7 is no longer in engagement with the groove curve 19 a. In this case, the cam roller 7 a engages in the groove curve 18 a. However, the lever 4 , 6 is not pivoted because the groove curve shape is circular.

Due to the use of a groove curve in the Nutkur vensscheibe 18 for the rest position of the thread guide lever 1 , the torsion spring 12 used in the embodiments described above is not required. Moving the lever 6 by means of the lifting magnet 15 is only possible in the area where the two groove curves 18 a and 19 a allow simultaneous engagement of the two cam rollers 7 , 7 a in the respective groove.

Fig. 9 shows another embodiment of the inven tion, in which no rest position for the thread guide lever 1 is provided. The device corresponds to the embodiment according to FIGS . 4 to 6, in which case no grooved cam has a circular projection which would make the rest position of the thread guide lever possible.

FIGS. 10 and 11 show a further embodiment of the device according to the invention, up in the guide lever through the yarn 1 through the Nutkurvenscheibe 8 and can be moved abbe. In the rest position of the lever, the cam roller 7 is disengaged from the groove curve 8 a and is held by the torsion spring 12 against the limiting part 20 , which is arranged stationary on the embroidery head, in position ge.

FIGS. 12 and 13 show a further embodiment of the present invention, in which by means of a guide 21 two different up and down movements of the yarn guide lever are realized (C and B), and a Ru heposition (A). The designated in FIGS . 1 to 11 with 6 lever is designated in FIG. 13 with 26a-26c. Depending on how far the fixed engagement means in the Ku lisse is moved axially, it is pivoted by the guide surfaces 22 , 24 , 27 of the link 21 and with it the Fa denführungshebel.

As is apparent from Fig. 12, there is an area 30 in which the guide surfaces 22 , 24 , 27 are aligned in the axial direction, so that the engaging means is movable in the axial direction and thus the transition from one guide surface to the next is possible is.

FIGS. 14 and 15 show a further development of the Ku lisse according to the FIGS. 12 and 13. In the setting shown in FIGS. 14 and 15, the cam surface by the boundary manure 33 circular (home position), so that on at concern of the engagement means this surface of the lever 4 a is not pivoted ver during a complete rotation of the shaft 9 or the link 31 . The remaining guide surfaces 34-38 form the first to fifth thread take-up curves for the corresponding deflection of the thread guide lever. With its two longitudinal webs 42 a and 42 b and 43 a and 43 b, the lever engages around the link 31 .

On the longitudinal webs engaging means 40 a and 40 b and 41 a and 41 b are arranged, which cooperate with the respective guide surfaces and the rest surface.

The reference numerals marked "a" show the lever in the rest position, in which the engaging means 40 a abuts the rest surface 33 of the link 31 .

The reference numerals marked "b" show the He bel as it is pivoted with its engaging means 41 b through the guide surface 38 . By axially shifting the lever 4 a or 4 b, it is possible to have a gripping means 40 , 41 in each case rest against one of the guide surfaces or the resting surface, provided that a torsion spring presses the engaging means against the respective surface.

Reference list

1

Thread guide lever

2nd

toothed hub

3rd

Shaft for thread guide lever

1

4th

Lever, works with the selected thread guide lever

1

together

5

Shaft for lever

4th

,

6

6

Lever, interacts with the grooved cam (s)

6

a lead

7

,

7

a Cam roller, engaging means

8th

Grooved cam

8th

a Groove curve, thread take-up curve

8th

b cylindrical projection of the grooved cam

8th

, Rest curve

9

Shaft for grooved cam

8th

10th

,

10th

a camp

11

,

11

a camp

12th

Torsion spring

13

adjusting spring

14

Carrier

15

Solenoid

15

a Armature (plunger) of the solenoid

15

16

second grooved cam

16

a Groove curve, second thread take-up curve

17th

axis

18th

Grooved cam with rest curve

18th

a

18th

a groove, rest curve

19th

Grooved cam with thread take-up curve

19th

a

19th

a groove, thread take-up curve

20th

Limiting part

21

Backdrop

22

Guide surface of the backdrop, rest curve

23

Area between guiding areas

22

and

27

24th

Guide surface of the backdrop, second thread take-up curve

25th

Cylinder jacket

26

a,

26

b,

26

c Lever with engagement means

27

Guide surface of the backdrop, first thread take-up curve

28

Area between guiding areas

24th

and

27

29

Area between guiding areas

24th

and wave

9

30th

Area in which the guide surfaces

22

,

24th

and

27

same radial distance from the shaft

9

to have

31

Grooved cam

32

Cylinder jacket; forms with its inner surface

33

the rest curve

33

Resting area

34-38

Guide surface of the backdrop, first to fifth thread bend curve

39

a,

39

b Cross bar

40

a,

40

b first means of intervention

41

a,

41

b second means of intervention

42

a,

42

b longitudinal web

43

a,

43

b longitudinal web

Claims (25)

1. Device for driving a thread guide lever ( 1 ) in an embroidery machine with at least one embroidery head, each embroidery head having at least one thread guide lever ( 1 ), and a maximum of only one thread guide lever ( 1 ) of an embroidery head via a gear from a shaft ( 9 ) is drivable, the shaft ( 9 ) driving the gearbox of at least one embroidery head, and the gearbox by means of a groove cam ( 8 ) located on the shaft ( 9 ) and a lever ( 4 ) rotatably mounted about an axis ( 5 ) ge 6) forms, wherein the lever (4, 6), the yarn guide lever (1) non-positively and / or positively drives, and for driving the yarn guide lever (1) in the He bel (4, 6) befindliches engagement means (7) the groove ( 8 a) of the groove cam ( 8 ) can be brought into engagement, characterized in that the engaging means ( 7 ) in the entire angular range or in a partial angular range of the rotating or stationary shaft ( 9 ) the groove ( 8 a) can be moved out and an adjusting device pivots the gripping means ( 7 ) into a predetermined rest position and / or holds it. 2. Device according to claim 1, characterized in that the engaging means ( 7 ) in the direction of the groove cam ( 8 ) is movable, displaceable, pivotable and / or pressurized, such that the engaging means ( 7 ) from the rest position in the direction the groove cam ( 8 ) is moved and / or pivoted and engages in the groove ( 8 a) immediately or after rotation of the shaft ( 9 ). 3. Apparatus according to claim 1 or 2, characterized in that the deflection angle in the Ru position of the not in the groove ( 8 a) engaging lever ( 4 , 6 ) at least one deflection angle of the lever ( 4 , 6 ) through the groove cam ( 8 ) corresponds. 4. The device according to claim 3, characterized in that the engaging means ( 7 ) is a bolt, an integrally formed or fastened projection or a rotatably mounted rotating body, in particular a roller, the axis of rotation of which is parallel to the axis of rotation of the grooved cam ( 8 ). 5. Device according to one of the preceding claims, characterized in that the Ju bull device consists of a spring ( 12 ) and a limita tion means ( 8 b, 20 ), the spring ( 12 ) moving out of the groove ( 8 a) engaging means ( 7 ) pressurized against the limiting means ( 8 b, 20 ). 6. The device according to claim 5, characterized in that the limiting means ( 8 b) is a on the groove cam ( 8 ) attached or molded ter tubular or sleeve-shaped projection, which serves as a rest curve for the engagement means ( 7 ). 7. The device according to claim 6, characterized in that the inner radius of the before jump ( 8 b) corresponds to the greatest radial distance between the rotation axis and the outer groove wall of the groove cam ( 8 ), the spring ( 12 ) the engagement means ( 7 ) in the Rest position against the inner wall of the projection ( 8 b) pressurized. 8. Device according to one of the preceding claims, characterized in that on the side facing away from the groove cam ( 8 ) of the lever ( 4 , 6 ) an additional holding means ( 7 a) is attached, mounted or formed. 9. The device according to claim 8, characterized in that the holding means ( 7 a) is a projection, a bolt or a rotating body, in particular rotatably gela ger. 10. Device according to one of claims 8 or 9, characterized in that the Ju bull device consists of a spring ( 12 ) and a limita tion means, the spring ( 12 ) pressurizing the holding means ( 7 a) against the limiting means. 11. The device according to claim 10, characterized characterized in that the limiting means an an additional part attached to the shaft or molded tubular or sleeve-shaped projection is, the spring is the holding means in the rest position pressurized against the inner wall of the projection, wherein the part on the side of the Lever is arranged and the tubular projection on the is arranged on the part facing the lever. 12. Device according to one of the preceding claims, characterized in that the inside radius of the projection of the limiting means selected in this way is that the means of intervention from the rest position only by axial displacement in the direction of the grooved cam and / or turning the shaft into the groove for engagement reaches.   13. Device according to one of claims 8 to 12, characterized in that the gripping means ( 7 ) and the holding means ( 7 a) lie on an axis. 14. Device according to one of claims 8 to 13, characterized in that the gripping means ( 7 ) and the holding means ( 7 a) are formed by a bolt penetrating the lever. 15. The device according to one of claims 8 to 14, characterized in that in addition to the first groove cam ( 8 , 19 ) a further groove cam ( 16 , 18 ) on the shaft ( 9 ) is attached such that the lever ( 4 , 6 ) is arranged between the two groove cams and either the engaging means ( 7 ) in the groove ( 8 a, 19 a) of the first groove cam ( 8 , 19 ) or the holding means ( 7 a) in the groove ( 16 a, 18 a ) engages the other groove curves disc ( 16 , 18 ). 16. The apparatus according to claim 15, characterized characterized in that at least one of the two Groove cams a tubular or sleeve-shaped Has a head start as a limiting means. 17. Device according to one of claims 8 to 14, characterized in that the lever is U-shaped at its end, wherein it is a on the shaft ( 9 ) fixed groove cam or link ( 31 ), which on their opposite flat sides each because it has at least one guide surface, with the legs ( 42 a, 42 b; 43 a, 43 b) of the U at least partially engages laterally, and on the inside of the legs engaging means ( 40 a, 40 b; 41 a, 41 b) are arranged, which are optionally in the respective sides of the scenes fen in the axial direction. 18. The apparatus according to claim 17, characterized in that at least on one of the flat sides of the link ( 31 ) is a tubular or sleeve-shaped projection as a limiting means ( 33 ) for the rest position. 19. Device according to one of claims 15 to 18, characterized in that the shapes of the guide surfaces or groove curves for generating different movements of the thread guide lever ( 1 ) differ. 20. Device according to one of the preceding claims, characterized in that the on direction has a drive ( 15 ) which reciprocates the lever ( 4 , 6 ) in the axial direction to the shaft ( 9 ). 21. Device according to one of the preceding claims, characterized in that the on direction has a drive which reciprocates the engaging means in the axial direction to the shaft ( 9 ). 22. Device according to one of the preceding claims, characterized in that the on direction has a drive which reciprocates the holding means together with the engaging means in the axial direction to the shaft ( 9 ). 23. The device according to one of claims 18 to 20, characterized in that the lever, each intervention agent or the intervention agent together with the holding means by means of an eccentric gear, a stroke  magnets or an electromagnetic drive back and forth is movable. 24. Device according to one of the preceding claims, characterized in that the Nutkur vensscheibe is replaced by a backdrop. 25. The device according to claim 24, characterized characterized that the backdrop several in axia ler direction has superimposed guide surfaces.