TW201943909A - Sewing machine - Google Patents

Abstract

A sewing machine has at least one sewing foot to hold down a piece of fabric during sewing. A pressure adjusting device is used to set a hold-down pressure exerted by the sewing foot when holding down the piece of fabric. A lifting device is provided to lift the sewing foot. The sewing machine has a common drive (12) for the pressure adjusting device and for the lifting device. A cam disc (13) is non-rotationally arranged on a drive shaft of the common drive (12), the cam disc (13) interacting with a cam lever (14) for lifting the sewing foot on the one hand and for driving the pressure adjusting device on the other. The cam lever (14) interacts with the cam disc (13) along a total pivoting path. The cam lever (14) has two cam followers (22, 24) arranged separately from one another, which interact with the cam disc (13) in each case at least in a section of the total pivoting path of the cam disc (13). The result is an increased operational safety of the common drive for the pressure adjusting device on the one hand and the lifting device on the other.

Description

Sewing machine

The content of German Patent Application No. DE 10 2018 206 088.6 is incorporated herein by reference.

The invention relates to a sewing machine.

Sewing machines of this type are known from EP 2 975 169 B1 and EP 2 105 526 B1. Document CN 202658372 U discloses a sewing foot lifting device including a stepper motor which interacts with other components of the lifting device via a cam disc. Document JP 07-231 991 A discloses a sewing machine with a presser foot drive. Document EP 2 351 881 A1 discloses a multi-head embroidery machine with a gear for a fabric presser foot of a fabric presser unit. Document US 2018/0016722 A1 discloses a sewing machine. A presser foot lifting device for a sewing machine is known from DE-PS 292 059.

The object of the present invention is to improve the operational safety of a common drive device for a pressure regulating device on the one hand and a lifting device on the other.

According to the invention, this object is achieved by a sewing machine with at least one sewing foot for pressing a fabric piece during sewing; with a pressing force for setting a pressing pressure applied by the sewing foot when pressing a fabric piece Pressure regulating device; with a lifting device for lifting the sewing foot; with a common driving device for the pressure regulating device and for the lifting device, wherein the cam disc interacts with the cam lever on the one hand to lift the sewing foot, on the other hand In order to drive the pressure regulating device non-rotatably arranged on the driving shaft of the common driving device, wherein the cam lever is configured in such a way to interact with the cam disc along the overall pivoting path of the cam disc, wherein the cam lever has Two cam followers, which are arranged separately from one another, are arranged to interact with the cam disc in each case at least in one section of the total pivot path of the cam disc.

The basic configuration of the common drive for the pressure regulating device on the one hand and the lifting device on the other hand is known from EP 2 975 169 B1, which makes the design of the sewing machine significantly simpler. One drive can be omitted. The associated control components can also be omitted. The common drive may be configured such that this does not impair the substantially independent functions of "foot lift" and "regulation". By omitting the drive, the entire design becomes more economical and compact. The cam lever designed in this way has two cam followers arranged separately from each other in order to interact with the cam disc in at least one section of the total pivot path of the cam disc in each case, which can ensure the cam disc The transfer of motion with the cam lever is performed safely. When a force is transmitted between a cam disc and a corresponding cam follower of a cam lever, an adverse force transmission direction can be avoided. Therefore, it is possible to prevent an undefined separation of the cam lever from the cam disc. The cam follower may be a member separate from but rigidly attached to the remaining cam lever. Alternatively, the cam follower may be part of the cam lever itself. The cam disc may have exactly one cam for interacting with two cam followers. In this case, the two cam followers can interact with different cam segments of the same cam of the cam disc.

The simultaneous interaction of the cam follower of the cam lever with the cam disc at least in one section of the total pivot path of the cam disc can ensure a particularly secure frictional connection between the cam lever and the cam disc. In a section of the total pivoting path of the cam disc, the two cam followers interact with the cam disc at the same time and can perform a "foot lift" function in the driving area. There, it is possible to prevent the cam lever from undesirably losing its frictional connection with the cam disc, for example when sewing thick fabric pieces, thereby allowing an undefined state of the common drive to be avoided.

An embodiment of a cam of a cam disc, for example, has a convex cam segment, which is adjacent to a corresponding concave cam segment on both sides of the convex cam segment, wherein the convex cam segment is two cam followers The cam segment where the moving member interacts with the cam disc at the same time, thereby creating a particularly secure frictional connection between the cam lever and the cam disc in a section of the total pivot path of the cam disc. In one embodiment of this type, two cam followers can surround the area of the convex cam segment, allowing a positive locking contribution of the force transmission connection between the cam lever and the cam disc to be obtained. The two cam followers can interact with the convex cam segment in the manner of two meshing gear segments.

One embodiment of a cam follower, such as a cam follower rigidly connected to a cam lever, is economical and safe to operate.

The cam disc and cam lever interact in such a way that the lifting of the sewing foot occurs in one direction of rotation of the cam, and the driving of the pressure regulating device occurs in the opposite direction of rotation, so that on the one hand it is used for Favorable decoupling of the foot lift from mechanical transmission elements for pressure regulation.

Setting a cam lever position called "minimum pressing pressure" by means of a cam groove formed in the cam allows a limited setting of the minimum pressing pressure.

The lifting shaft for transmitting the switching operation force from the cam lever to the sewing foot allows the driving device to be arranged at a distance from the sewing foot. Viewed in a plane perpendicular to the lifting shaft, the cam follower may be arranged between the lifting shaft and the driving shaft of the common driving device. This arrangement can simplify the cam design of the cam disc.

The drive device configured as a stepper motor allows a gradual setting of the pressing pressure to be set, in particular. This can be used to adapt to the corresponding sewing environment. Fine adjustment of the lifter height is also advantageous. When sewing thick fabric pieces, higher lifter heights can be set. When sewing thinner fabric pieces, a lower lifter height can be set.

The arrangement of the drive means may orient the drive shaft of the drive means, in particular the drive shaft of the stepper motor, towards the sewing foot of the sewing machine or, alternatively, the arrangement may orient the drive shaft in a direction away from the sewing foot. For example, depending on the space requirements of the drive in the transverse or longitudinal direction of the sewing machine arm, this allows the design of a drive that is compact in decisive dimensions.

The adjustment range of the drive shaft of the common drive device between the "minimum pressing pressure" cam lever position and the "maximum pressing pressure" cam lever position exceeds 180 °, allowing fine adjustment of the pressing pressure without affecting the positioning accuracy of the driving device or Incrementally demands too much. With such a wide adjustment range, a low-torque drive of a cam disc and a small-pitch cam can be achieved at the same time.

In addition, it has been recognized that a cam lever with two cam followers arranged separately from each other and a cam disc having a corresponding shape can also be used as a mounting assembly for retrofitting. This allows an existing drive including a cam lever with exactly one cam follower to be replaced by a drive according to the invention, said drive comprising two cam followers, so that a corresponding relationship is created between the cam lever and the cam disc Safe force transmission.

The sewing machine 1 has a stand 2, an arm 3, and a head 4, and therefore, together with the bottom plate 5, an overall C-shaped structure of the sewing machine 1 is obtained. An arm shaft (not shown in detail) driven by the main driving device drives the needle bar 6 with the sewing needle 7 fastened thereto in a reciprocating up and down motion. During this movement, the needle 7 passes through a needle hole in a needle plate, which forms part of a support plate 8 which in turn is the upper part of the bottom plate 5 of the housing of the sewing machine 1.

The sewing machine 1 has a sewing foot 9 for pressing a piece of fabric during sewing, said sewing foot is also referred to as a presser foot. The sewing foot 9 is attached to the presser foot lever 10.

The component indicated by the reference numeral 11 in its entirety in FIG. 2 is used to set the pressing pressure applied by the sewing foot 9 when pressing the fabric sheet, and to raise the sewing foot.

The assembly 11 includes a pressure regulating device for setting a pressing pressure, a lifting device for lifting a sewing foot, and a common driving device for the two devices. The pressure regulating device and the lifting device will be described in detail below. The common driving device is configured as a stepping motor 12. The drive shaft 12a (see, for example, FIG. 3) of the stepper motor 12 is oriented away from the presser foot lever 10, and therefore, the free end of the drive shaft 12a is directed toward the observer in a direction opposite to the viewing direction III of the view, as shown in FIG.

The drive shaft of the stepping motor 12 is non-rotatably connected to the cam disc 13. The cam disc 13 interacts with the cam lever 14 to raise the sewing foot 9 on the one hand and drive the pressure regulating device on the other. The cam lever 14 interacts with the cam disc 13 along a total pivot path of the cam disc 13. The cam lever 14 is again non-rotatably connected to a lifting shaft 15 which runs parallel to the arm shaft in the arm 3 of the sewing machine 1 and is rotatably mounted to the frame of the sewing machine 1. Non-rotatably connected to the lifting shaft 15 is a lifting lever 16 which interacts with a presser foot driver 17 which is rigidly connected to the presser foot lever. The lift shaft 15 is used to transmit a switching operation force from the cam lever 14 to the sewing foot 9.

At the end opposite the cam lever 14, the lifting shaft 15 is eccentrically hinged to the tensioning rod 18 with respect to the longitudinal axis of the lifting shaft, said tensioning rod 18 being pressed against the compression spring 21 from above by means of a sleeve 19 to The sewing foot 9 is pressed, which is not shown in FIG. 2.

Arranged between the other sleeve 20 and the presser foot driver 17 is a compression spring 21 which is fixed to the frame and the presser foot bar 10 passes through the sleeve, said compression spring spirally surrounding the presser foot bar A paragraph of 10.

Figures 2 and 4 show the assembly 11 in a "minimum pressing pressure" position in the drive position. Compared to FIG. 3, a section of the bottom plate of the cam lever 14 is omitted in FIG. 4 to show its interaction with the cam lever 14 in more detail.

The first follower bolt 22 of the cam lever 14 forming the first cam follower of the cam lever 14 engages the cam groove 23 of the cam disc 13, which defines the "minimum pressing pressure" cam lever position. In the associated pivot position of the lifting shaft 15, the tensioning rod 18 exerts a minimum compressive force on the sleeve 19. The compression spring 21 is minimally biased. The force of the compression spring 21 is transmitted to the presser foot lever 10 via the presser foot driver 17, so that a corresponding minimum pressing force of the sewing foot 9 is generated during operation of the sewing machine 1. In this "minimum pressing pressure" driving position, the lift lever 16 has been disengaged from the presser foot driver 17.

Figures 5 and 6 show the "maximum foot lift" drive position. To reach this position, the stepper motor 12 is operated from the "minimum pressing pressure" position shown in Figs. 2 to 4, in such a way that its drive shaft is rotated counterclockwise from the view of Figs. 3 to 6 by about 80 °. As a result, the second follower bolt 24 of the cam lever 14 forming the second cam follower of the cam lever 14 runs on the cam disc 13 in a clockwise direction up to the cam region 24 in which the cam disc 13 It also acts as a lever on the second follower bolt 24. In this position, the lifter lever 16 presses the presser foot driver 17 upward in the direction of the sleeve 20 fixed to the frame against the compression force of the compression spring 21 and moves along the presser lever 10 to lift the sewing foot 9.

The two follower bolts 22, 24 of the cam lever 14 are arranged separately from each other. The two follower bolts 22 and 24 are rigidly connected to the cam lever 14.

The two follower bolts 22, 24 are each arranged in such a way as to interact with the cam disc 13 at least in one section of the total pivot path of the cam disc 13. In the pivot path section of the “minimum pressing pressure” cam lever position (see FIGS. 3 and 4), the first follower bolt 22 interacts with the cam disc 13 in the region of the cam groove 23. In the lower “maximum foot lift” cam lever position (see FIGS. 5 and 6), the second follower bolt 24 interacts with the cam area 25. The cam groove 23 on the one hand and the cam area 25 on the other hand are two concave cam sections of the cam disc 13. Between these two concave cam segments 23, 25, the cam disc 13 has a convex cam segment 26, which is arranged in the form of a convex angle of the curve of the cam disc 13.

7 and 8 show the "middle foot lifting height" driving position between the above two driving positions "minimum pressing pressure" and "maximum foot lifting". In this "middle foot lift height" drive position, the convex cam segment 26 engages the space between the two follower bolts 22, 24, thereby providing a positive locking force contribution to ensure safe contact between the cam lever 14 and the cam disc 13 . For example, regardless of the force transmitted to the cam lever 14 via the fabric sheet, the presser foot 9 and the presser foot lever 10, the cam lever 13 and the cam disc 13 can be securely contacted.

In a section of the area between the "minimum pressing pressure" drive position (see Figs. 3 and 4) and the "maximum foot lift" drive position (see Figs. 5 and 6), the two follower bolts 22, 24 are simultaneously Interacting with the cam disc 13, in other words, they are in contact with the cam disc 13 at the same time.

Figures 9 and 10 show the "maximum pressing pressure" drive position. Compared to FIG. 3, the stepping motor 12 has been converted in such a manner that its drive shaft has caused the cam disk 13 to pivot about 320 ° in the clockwise direction compared to the position shown in FIG. Then, the first follower bolt 22 of the cam lever 14 runs along the cam disc 13 to the "maximum pressing pressure" cam region 27. In this “maximum pressing pressure” position, the second follower bolt 24 has disengaged from the cam disc 13.

In this position, the tension rod 18 is moved downwards due to its eccentric connection with the lifting shaft 15, and therefore a tension force is exerted on the sleeve 19, so that the sleeve is pushed down to the maximum extent by the tension rod 18. As a result, the compression spring 21 is maximally biased. The result is the maximum pressing pressure of the presser foot lever 10 and therefore the sewing foot 9 on the fabric sheet during operation of the sewing machine 1. In the “maximum pressing pressure” position, the lift lever 16 is disengaged from the presser foot drive 17 again. This makes the cam lever 14 in the "maximum pressing pressure" driving position shown in Figs. 9 and 10 compared with the "minimum pressing pressure" driving position shown in Fig. 3 and the driving position shown in Figs. 9 and 10 Pivot approximately 60 ° counterclockwise.

Therefore, the cam disc 13 and the cam lever 14 interact in such a manner that the lifting of the sewing foot 9 occurs in one rotation direction of the rotation of the cam, and the driving of the pressure regulating device occurs in the rotation direction opposite thereto.

The adjustment range of the drive shaft of the stepping motor 12 between the "minimum pressing pressure" cam lever position (see Fig. 3) and the "maximum pressing pressure" cam lever position (see Fig. 5) exceeds 180 °.

The stepper motor 12 can be actuated by an operator by means of a pedal of the sewing machine 1 for foot lifting, for example.

In order to set the pressing pressure, it can be set by means of a control device 26 shown schematically in FIG. 1. The control device 26 has a signal connection with the stepper motor 12 in a manner not shown in more detail.

Next, with reference to FIGS. 11 and 15, another embodiment of an assembling assembly 28 that can be used in the sewing machine 1 for setting the pressing pressure and for raising the sewing foot instead of the assembling assembly 11 described above will be described. Parts and functions corresponding to those already explained above with reference to the assembly 11 are denoted by the same reference numerals and will not be discussed in detail.

In the mounting assembly 28, the stepper motor 12 is arranged in such a manner that its drive shaft faces the direction of the presser bar 10, in other words toward the viewer of FIG. 12, and is again oriented in a direction opposite to the viewing direction XII. Therefore, in the assembly assembly 28, the orientation of the drive shaft of the stepper motor 12 with respect to the presser foot lever 10 is opposite to that of the assembly assembly 11.

Figures 11 and 12 show the "minimum pressing pressure" drive position. In this position, the first follower bolt 22 of the cam lever 14 stays again in the cam groove 23 of the cam disc 13.

Figure 13 shows the "maximum foot lift" drive position. In this position, the stepper motor 12 of the assembly 28 is operated in such a way that starting from the "minimum pressing pressure" drive position shown in Fig. 12, the cam disk rigidly connected to the drive shaft of the stepper motor 13 is rotated approximately 180 ° counterclockwise, as seen from FIGS. 12 and 13. In this “maximum foot lift” drive position, the second follower bolt 24 engages another concave cam area 25 of the cam disc 13, which concave cam area corresponds to the cam area 25 of the mounting assembly 11. Starting from the "minimum foot pressure" drive position, this pivoting movement of the cam disc 13 causes the cam lever 14 to pivot about 45 ° counterclockwise. In this position, the lifter lever 16 presses the presser foot driver 17 upward again in the direction opposite to the compressive force of the compression spring 21 and in the direction of the sleeve 20 fixed to the frame, as assembled above with reference to FIGS. 5 and 6 Component 11 has already been described.

FIG. 14 illustrates a “middle foot lift” driving position, in other words, an intermediate driving position between the “minimum foot pressure” position shown in FIG. 12 and the “maximum foot lift” position shown in FIG. 13. In this "middle foot lifting height" drive position, the two drive bolts 22, 24 interact with the convex cam segment 26 of the cam disc 13 at the same time.

Between the two concave cam regions 23 and 25 of the cam disk 13 of the mounting assembly 28, there is another convex cam segment 26, which is higher in the cam disk 13 of the mounting assembly 28 than in the mounting assembly 11. The cam disc 13 has a larger shape.

Fig. 15 shows the "maximum pressing pressure" driving position again. Compared to the drive position shown in FIG. 12, the cam disk 13 of the mounting assembly 28 is again pivoted by the stepper motor 12 in a clockwise direction by approximately 210 °. The first follower bolt 22 then runs along the cam disc 13 of the mounting assembly 28 up to the "maximum pressing pressure" cam segment 27. In this "maximum pressing pressure" driving position, the cam lever 14 is pivoted about 90 ° in the clockwise direction compared to the "minimum foot pressure" driving position shown in Figs. 12 and 15.

In this position, the tension rod 18 has moved downwards due to its eccentric connection with the lifting shaft 15. At the lifting shaft, the tension rod 18 applies a corresponding tension force to the sleeve 19, so the sleeve Pressed by the tension rod 18 to the maximum extent. This allows the compression spring 21 to be maximally biased. The result is the maximum pressing pressure exerted on the fabric piece by the presser foot lever 10 and therefore the sewing foot 9 during operation of the sewing machine 1. In the “maximum pressing pressure” position, the lift lever 16 is disengaged from the presser foot drive 17 again. In this “maximum pressing pressure” position, the second follower bolt 24 has disengaged from the cam disc 13.

In the “maximum pressing pressure” position, the cam area 27 also serves as a reference stop for the stepper motor 12. To this end, the stepper motor 12 is moved to the "maximum pressing pressure" drive position until the first follower bolt 22 rests on a stop formed by the cam region 27. The cam area 27 provided with the stopper does not need to use another reference sensor, otherwise it may be formed by a grating or an inductive switch.

In the “minimum pressing pressure” driving position (see FIGS. 3 to 4), for example, the two followers 22 and 24 of the assembly assembly 11 are arranged on the lift shaft 15 and stepped in a plan view as shown in FIGS. Between the drive shafts 12a of the motor 12. For example, in the "maximum foot lift" driving position (see FIG. 13), the two follower bolts 22, 24 of the assembly 28 are substantially the same as the drive shaft 12a of the stepper motor 12 in a plan view as shown in FIG. On a horizontal plane.

16 and 17 show perspective views of the cam disc 13 (FIG. 16) and the cam lever (FIG. 17) of the assembly 28, respectively.

The cam disc 13 and the cam lever 14 of the mounting assembly 28 can be used as a retrofit mounting assembly for retrofitting an existing driver mounting assembly whose lifting rod is initially provided with exactly one follower.

1‧‧‧ sewing machine

2‧‧‧ bracket

3‧‧‧ arm

4‧‧‧ head

5‧‧‧ floor

6‧‧‧ Needle bar

7‧‧‧ sewing needle

8‧‧‧ support plate

9‧‧‧ sewing feet

10‧‧‧Presser foot lever

11, 28‧‧‧Assembly components

12‧‧‧stepper motor

12a‧‧‧Drive shaft

13‧‧‧ cam disc

14‧‧‧ cam lever

15‧‧‧lift shaft

16‧‧‧Lift lever

17‧‧‧Presser foot driver

18‧‧‧ Tightening lever

19‧‧‧ sleeve

20‧‧‧ sleeve

21‧‧‧Compression spring

22, 24‧‧‧ follower bolt

23‧‧‧ cam groove; concave cam segment

25‧‧‧ cam area; concave cam segment

26‧‧‧ convex cam segment; control device

27‧‧‧ cam area

Exemplary embodiments of the present invention will be explained in more detail below with reference to the accompanying drawings, in which

Figure 1 shows a perspective front view of the sewing machine;

Fig. 2 shows another perspective view of the assembling assembly of the sewing machine as shown in Fig. 1. The assembling assembly is provided with a pressure regulating device for setting the pressing pressure applied by the sewing foot when pressing the fabric piece, and Lifting device for lifting sewing feet and a common driving device for these devices;

FIG. 3 shows a plan view of the assembly assembly in the “minimum pressing pressure” position as viewed from the viewing direction III shown in FIG. 2;

4 shows a view as shown in FIG. 3, in which a section of the bottom plate of the cam lever of the driving device is omitted;

Figure 5 shows a view similar to Figure 3 with the assembly assembly in the "maximum foot lift" position;

Fig. 6 shows the assembly assembly shown in Fig. 5, wherein a section of the bottom plate of the cam lever is omitted again;

Fig. 7 shows a view similar to Fig. 3 of the assembly assembly in the "middle foot lifting height" position;

FIG. 8 shows the assembly assembly shown in FIG. 7, in which a section of the bottom plate of the cam lever is omitted again;

Fig. 9 shows a view similar to Fig. 3 of the assembly assembly in the "maximum pressing pressure" position;

FIG. 10 shows the assembly assembly shown in FIG. 9, wherein a section of the bottom plate of the cam lever is omitted again;

FIG. 11 shows a view of another embodiment of an assembly assembly similar to FIG. 2 with a pressure adjusting device for setting a pressing pressure applied by a sewing foot when pressing a fabric piece, with The lifting device for lifting the sewing feet and the common driving device with these devices can be used in place of the mounting assembly shown in FIG. 2 as shown in FIG. 11;

FIG. 12 shows a plan view of the assembly assembly at the “minimum pressing pressure” position shown in FIG. 11 as viewed from the viewing direction XII, and similar to FIG. 4, a section of the bottom plate of the cam lever is omitted;

13 shows a view similar to FIG. 12 of the assembly assembly in the “maximum foot lift” position;

14 shows a view similar to FIG. 12 of the assembly assembly in the “middle foot lift height” position;

Fig. 15 shows a view similar to Fig. 12 of the assembly assembly in the "minimum pressing pressure" position;

FIG. 16 shows a perspective view of a cam disc of the mounting assembly shown in FIG. 11; and

FIG. 17 shows a perspective view of a cam lever of the mounting assembly shown in FIG. 11.

Claims (10)

A sewing machine having: At least one sewing foot for pressing the fabric piece during sewing, Pressure regulating device for setting the pressing pressure applied by the sewing foot when pressing the fabric piece, Lifting device for lifting sewing feet, Common drive for pressure regulators and lifts, Among them, the cam lever interacts on the one hand to raise the sewing foot and on the other hand to drive the pressure regulating device of the cam disk non-rotatably arranged on the drive shaft of the common drive device, wherein the cam lever is configured to The total pivot path interacts with the cam disc, Among them, the cam lever has two cam followers arranged separately from each other, the cam followers being arranged to interact with the cam disc in each case in at least a section of the total pivoting path of the cam disc. The sewing machine according to claim 1, wherein the two cam followers are arranged to interact with the cam disc simultaneously in at least a section of a total pivot path of the cam disc. A sewing machine as claimed in claim 2, wherein the cam of the cam disc has a convex cam section which is adjacent to a corresponding concave cam section on both sides of the convex cam section, wherein The convex cam segment is described, and the two cam followers interact with a cam disc at the same time. The sewing machine according to claim 1, wherein the two cam followers are configured as followers rigidly connected to a cam lever. The sewing machine according to claim 1, wherein the cam disk and the cam lever interact in such a manner that the lifting of the sewing foot occurs in one rotation direction of the cam rotation, and the driving of the pressure regulating device occurs with the one The direction of rotation is opposite. The sewing machine according to claim 1, wherein the cam disc has a cam groove for setting a "minimum pressing pressure" cam lever position. The sewing machine according to claim 1, further comprising a lifting shaft for transmitting a switching operation force from the cam lever to the sewing foot. The sewing machine according to claim 1, wherein the driving device is configured as a stepping motor. The sewing machine according to claim 1, wherein the drive shaft including the common drive device has an adjustment range between the "minimum pressing pressure" cam lever position and the "maximum pressing pressure" cam lever position, and the adjustment range is greater than 180 °. A retrofit assembly for use in a sewing machine as described in claim 1 having: A cam disc that can be arranged on the drive shaft of a common drive, The cam lever, which interacts with the cam disc, is used to lift the sewing foot on the one hand and to drive the pressure regulating device on the other hand, Wherein, the cam lever is configured to interact with the cam disc along a total pivot path of the cam disc, Among them, the cam lever has two cam followers arranged separately from each other, the cam followers being arranged to interact with the cam disc in each case in at least a section of the total pivoting path of the cam disc.