Electrically driven switch for dual-belt conveyors

Abstract

This invention relates to a switch for use with first and second transport sections, wherein the switch includes a switch arm supported in a rotatable manner about a first axis of rotation, guided in a linearly movable manner along the first axis of rotation, and capable of reciprocating between a first and a second end position. The switch arm has a concavely curved turning surface, formed such that when the switch arm is in the first end position, the transported item can be transferred from the first transport section to the second transport section by means of the turning surface, or vice versa. In the second end position, the switch arm is completely positioned below the transport plane, allowing the transported item to move along the first transport section across the switch. According to the invention, the switch arm is driven by a single electric motor via a transmission mechanism.

Description

Technical Field

[0001] The present invention relates to a switch as described in the preamble of claim 1 and a transport system having such a switch. Background Technology

[0002] In a video available at http: / / www.youtube.com / watchv=sNDoOjlFevI&t=8s, dated March 17, 2021, starting at 1:51, a switch with a switch arm can be seen. The switch arm is lowered below a transport plane defined by a conveyor belt in a second end position. In a first end position, the switch arm is lifted through the transport plane, wherein the switch arm is rotated to a position in which a transported object, in the form of a workpiece support, is transferred from a first transport section to a second transport section. Summary of the Invention

[0003] The advantage of this invention is that it can move the switch arm purely with electricity, especially without compressed air. The entire drive unit is constructed in a particularly simple and inexpensive manner. The electric drive unit can be operated particularly easily, requiring neither a frequency converter nor a servo regulator.

[0004] According to claim 1, the switch arm is driven by a transmission mechanism to a single electric motor such that the switch arm can move back and forth between the first and second end positions solely by drive from the electric motor in two degrees of freedom coupled via the transmission mechanism. In the second end position, the entire switch is preferably positioned below the transport plane so that components of the switch do not obstruct the path of the transported goods. The traction device is preferably a conveyor belt or conveyor chain. The traction device is preferably supported by an assigned support, which preferably comprises at least one profile body extending along the traction device or the corresponding transport direction with a constant cross-sectional shape.

[0005] Advantageous extensions and improvements of the invention are described in the dependent claims.

[0006] It can be specified that the transmission mechanism is designed such that, at the first end position, it is self-locking at least with respect to the linear movement of the switch arm along the first axis of rotation. Thus, the weight of the switch arm is borne solely by the transmission mechanism, without requiring current to be applied to the electric motor. Overheating of the electric motor is thus avoided because current is applied to it only briefly during the movement of the switch arm. With respect to the rotational movement of the switch arm, the first and / or second transport sections can form end stops for the switch arm. However, it is also conceivable that the transmission mechanism forms such end stops.

[0007] It can be specified that the transmission mechanism is designed such that it forms an end stop in the second end position for the movement of the switch arm along the first axis of rotation toward the second end position. Thus, in the second end position, the weight of the switch arm is supported solely by the transmission mechanism, without needing to apply current to the electric motor. The transmission mechanism can additionally form an end stop for the rotational movement of the switch arm toward the second end position. In the second end position, the first or second transport section preferably does not form an end stop for the rotational movement of the switch arm, as this is cumbersome.

[0008] It can be specified that the electric motor is manufactured as a stepper motor, which is in a drive connection with the transmission mechanism via a toothed belt, wherein the corresponding toothed belt drive is designed such that it results in a transmission ratio greater than 2. Stepper motors are particularly inexpensive and can be operated in a simple manner. However, with the proposed toothed belt drive, sufficiently large torque can be generated. The end stop discussed above can be used to move to the defined starting position of the switch arm. Here, it is easily tolerated that the step distance of the stepper motor is skipped during the corresponding initial stroke. In the subsequent normal operation, the design according to the invention reliably eliminates such skipping of the step distance. Therefore, the switch can, in its simplest case, operate entirely without a sensor for the position of the switch arm, although precise positioning is still possible. The aforementioned transmission ratio is preferably greater than 2.8. The transmission ratio is preferably defined as the rotational speed of the electric motor divided by the (input) rotational speed of the transmission mechanism. A gear ratio greater than one therefore corresponds to a gear ratio that shifts to a slower speed (https: / / de.wikipedia.org / wiki / %C3%9Cbersetzung_(Technik)). Due to the toothed belt, the required directional accuracy between the electric motor and the transmission mechanism is relatively small.

[0009] It can be specified that the transmission mechanism includes a control roller rotatably supported about a second axis of rotation, the control roller being in a rotary drive connection with the electric motor, wherein the control roller extends at least partially along the second axis of rotation with a constant cross-sectional shape, wherein the corresponding circumferential surface has a control pitch varying along its circumference relative to the second axis of rotation. The control pitch correspondingly defines the travel position of the switch arm. Preferably, the control pitch between the first and second endpoint positions varies continuously and without bends. The control roller is preferably fixedly connected to the toothed pulley of the toothed belt drive device explained above.

[0010] It can be specified that the control spacing is maximum at the first endpoint position. Therefore, the self-locking explained above at the first endpoint position can be achieved in a simple manner. Preferably, the control spacing changes continuously and without bends beyond the first endpoint position. Thus, at the first endpoint position, the slope of the control spacing within the range of rotation angles is zero, resulting in particularly good self-locking. Needless to say, the portion of the circumferential surface of the control roller after the first endpoint position is not used during operation to move the switch arm along the first axis of rotation.

[0011] It can be specified that the control spacing is minimum at the second endpoint position. Thus, the movement of the control roller about the direction along the first axis of rotation forms the end stop discussed above. Behind the second endpoint position, that is, outside the circumferential section of the circumferential surface utilized during operation, the control spacing can be constant and equal to the minimum control spacing. Outside the utilization range of the circumferential surface between the first and second endpoint positions, the control spacing preferably varies rapidly between its minimum and maximum values.

[0012] It can be specified that the switch arm is rotatably supported on a separate slide about a first axis of rotation, wherein the slide is guided in a manner that allows linear movement along the direction of the first axis of rotation, and wherein the control surface of the slide is disposed on the circumferential surface of the control roller. Thus, variable control pitch can be converted into reciprocating linear motion of the switch arm particularly easily. The first axis of rotation is preferably oriented parallel to the direction of gravity, wherein the circumferential surface of the control roller supports the weight of the slide along with the switch arm via the control surface.

[0013] It can be specified that the control roller has a control groove or control protrusion in a region of its circumferential surface, the control groove or control protrusion extending helically about a second axis of rotation, wherein the switch arm is fixedly connected to a separate control arm, the control arm being coupled to the control groove or control protrusion at its free end. It is also conceivable that the switch arm itself forms the control arm. In contrast, the preferred additional control arm achieves a switch arm that is particularly space-saving. Furthermore, the control roller can also be advantageously arranged between two profile bodies of the first transport section, especially if the distance between the two profile bodies is small.

[0014] It can be specified that the slide includes a base plate arranged parallel to the transport plane, wherein the switch arm and control arm are arranged on opposite sides of the base plate. The control arm and switch arm are preferably fixedly connected to each other by cylindrical shaft sections, wherein the shaft sections are preferably rotatably supported on the base plate by means of sliding or rolling bearings. The base plate is preferably made as a flat plate with a constant thickness.

[0015] It can be specified that the first rotation axis is arranged within a range of 30% to 70%, preferably 40% to 60%, of the length of the steering surface along the direction of movement of the transported goods. The first rotation axis is transverse to the steering surface and preferably extends through the switch arm, wherein the precise position can be chosen with considerable freedom.

[0016] Furthermore, a claim is made for a transport system having first and second transport sections and a switch according to the invention, wherein at least the first transport section comprises two parallel, spaced-apart, continuously operating traction devices, wherein all traction devices define a common transport plane, wherein a first axis of rotation is oriented perpendicular to the transport plane, wherein the transport plane is arranged between the two traction devices of the first transport section.

[0017] It goes without saying that the features mentioned above and explained below can be used not only in the combinations described, but also in other combinations or individually, without departing from the scope of the invention. Attached Figure Description

[0018] The invention will now be explained in detail with the aid of the accompanying drawings.

[0019] Figure 1 A perspective view of a transport system having a switch according to the invention is shown, wherein the switch arm is in a first end position; Figure 2 It shows according to Figure 1 The transport system, wherein the switch arm is in the second end position, Figure 3 It shows according to Figure 1 A perspective view of the switch of the transport system without an enclosing housing; and Figure 4 It shows according to Figure 3 Another perspective view of the switch, in which other components are omitted. Detailed Implementation

[0020] Figure 1 A perspective view of a transport system 66 having a switch 10 according to the invention is shown, wherein the switch arm 30 is in a first end position. The transport system 66 includes first and second transport sections 61; 62, which are T-shapedly assembled on each other. Each of the two transport sections 61; 62 has two continuously operating traction devices 63, which are arranged parallel to each other and spaced apart, wherein the upward-pointing surfaces of all traction devices 63 are arranged in a common transport plane. The traction devices are currently continuous transport belts, which are held in motion by assigned supports 64. The supports 64 are currently made of aluminum-extruded profiles. Each of the two transport sections 61; 62 has a traction device drive 65, which enables the two assigned traction devices 63 to be moved synchronously. The traction device drive 65 preferably includes an electric motor.

[0021] In the current transport system 66, it is preferable to transport a transport object 60 in the form of a workpiece support. Here, in the simplest case, it can be a flat plate with a constant thickness, which in turn carries a workpiece (not shown), which is transported, for example, between different processing stations on the production line.

[0022] Using the switch 10 according to the invention, it is possible to... Figure 1 The transport item 60 shown is transferred from the first transport section 61 to the second transport section 62. The switch arm 30 is used for this purpose. Figure 1 In the first endpoint position shown, above the transport plane, the switch arm is rotated to a position in which the curved steering surface 32 of the switch arm extends over the entire width of the first transport section 61. The transported object 60, moving by means of the traction device 63 of the first transport section 61, is thus stopped by the steering surface 32 on the switch arm 30 and turned toward the second transport section 62. Once the transported object 60 engages with the traction device 63 of the second transport section 62, the rotational movement of the transported object 60 caused by the corresponding driving force tends to end.

[0023] To support the rotational movement of the transported object 60 within the switch 10, an arc-shaped inner guide surface 11 and a straight or slightly curved outer guide surface 12 are fixedly arranged on the transport system 66. The outer guide surface 12 continuously and without bends continues the curved turning surface 32 on the switch arm 30 at the first endpoint position. Corresponding components simultaneously form end stops for the switch arm 30.

[0024] Figure 2 It shows according to Figure 1 The conveying system 66, wherein the switch arm 30 is in the second end position. The switch arm 30 is rotated such that it is completely between the two supports 64 of the first conveying section 61, wherein the switch arm is completely below the conveying plane. Figure 2 The transport 60 shown is thus moved in a straight line across the switch 10 by the traction device 63 of the first transport segment 61, wherein the transport does not turn toward the second transport segment 62.

[0025] Figure 3 It shows according to Figure 1 A perspective view of a switch 10 of a transport system without an enclosing housing. The switch 10 includes a base 70, which is capable of being fixedly attached to a first transport section (in... Figure 1 (Ref. 61) are connected, in particular screwed together. The base 70 currently includes a first base member 71, two second base members 72, and a third base member 73, which are fixedly connected to each other, in particular screwed together. The first base member 71 is plate-shaped, wherein the two second base members 72 are vertically assembled to the first base member 71, thereby generally forming a U-shape. The second base members 72 are respectively connected by assigned cylindrical guide rods (in... Figure 4 Reference numeral 24) runs through the figure, and the guide rods are supported on the associated second base member 72 in a linearly movable manner. The guide rods in their... Figure 3 The upper end side of the slide is fixedly connected to the base plate 21 of the slide 20, and in particular, screwed together.

[0026] Furthermore, the second base member 72 has a rotary bearing in the form of a radial rolling bearing (in Figure 4 (Ref. 46 in the accompanying drawing) The control roller 41 is supported by the rotary bearing in a rotatable manner about the second axis of rotation 42. The control roller 41 is arranged between two second base members 72, wherein the control roller is held in a manner that prevents it from moving along the direction of the second axis of rotation 42 of the rotary bearing 46.

[0027] The third base member 73 is an L-shaped curved plate, which is fixed by one L-leg, particularly screwed onto the lower side of the first base member 71. The other L-leg forms a flange on which the electric motor 50 is fixed; the electric motor is currently configured as a stepper motor. The drive shaft of the electric motor 50 is fixedly connected to a smaller first toothed pulley 52. ​​The control roller 41 is fixedly connected to a larger second toothed pulley 53. The first and second toothed pulleys 52 and 53 are in a rotational drive connection via a toothed belt, wherein the corresponding transmission ratio is significantly greater than one, such as three. The electric motor 59 thus rotates relatively quickly and with a small torque, while the control roller 41 rotates slowly with a higher torque. The control roller 41 is part of a transmission mechanism 40, which is to be referenced... Figure 4 A detailed explanation will be provided.

[0028] It should also be mentioned that the cover plate 25 at the slide 20 is a component of the housing.

[0029] Figure 4 It shows according to Figure 3 Another perspective view of the switch 10, in which other components, namely the base plate and the second base member, are omitted. Thus, the rotary bearing 23 is visible first, by which the switch arm 30 is rotatably supported about a first axis of rotation 31. This rotary bearing is fixedly received in the base plate (in... Figure 3 As shown in reference numeral 21 in the attached drawing, a rotary bearing is penetrated by a cylindrical shaft section that connects the switch arm 30 to the control arm 33 in a torsional manner. Correspondingly, the switch arm 30 and the control arm 33 are arranged on opposite sides of the base plate. The control arm 33 has a cylindrical control cam 37 on its free end 34 away from the first axis of rotation 31, which engages in a helical control groove 45 on the outer circumferential surface of the control roller 41.

[0030] In addition, Figure 4 As can be seen, the two cylindrical guide rods 24 guide the slide block in a linearly movable manner along the first rotation axis 31. The guidance is achieved using two sliding sleeves 74, which are fixedly mounted to the associated second base member (in...). Figure 3 As shown in the attached figure (reference numeral 72), the ends of the two guide rods 24 facing away from the base plate are respectively surrounded by helical springs 26, which pre-tighten the slide block towards the second endpoint position, thereby pressing the control surface 22 on the slide block against the circumferential surface of the control roller 41.

[0031] In addition to the control groove 45, the circumferential surface of the control roller 41 extends along the second rotation axis 42 with a constant cross-sectional shape. This cross-sectional shape is defined by a control pitch 44, which varies along the circumference of the control roller 41. Correspondingly, the control pitch 44 on the control surface 22 of the slide defines the travel position of the slide. Therefore, the decisive control pitch 44 can be changed by rotating the control roller 41 using the electric motor 50. As the control roller 41 rotates, the position where the control cam engages with the control groove 45 simultaneously changes, causing a change in the rotational position of the switch arm 30. Therefore, the rotation of the electric motor 50 simultaneously causes both reciprocating linear motion and rotational motion of the switch arm 30, i.e., motion in two degrees of freedom.

[0032] Figure 4 The second end position of the switch arm 30 is shown, in which the decisive control spacing 44 is minimized at the control surface 22. The control roller 41 thus forms an end stop for the downward movement of the slide, so that the weight of the slide is supported by the control roller 41. Therefore, the switch arm 30 is held in this position without needing to supply current to the electric motor 50. This reliably prevents overheating of the electric motor 50.

[0033] Furthermore, it should be noted that the first rotation axis 31 is approximately located at the center of the switch arm 30.

[0034] List of reference numerals 10 Switches 11 Internal guide surfaces 12 External guiding surfaces 20 sliders 21 Base Plate 22 Control Surface 23 Rotary bearings 24 guide rods 25 Cover plate 26. Coil spring 30 Switch Arm 31 First axis of rotation 32 Turning surface 33 Control Arm 34. Free end of the control arm 37 Control bumps 40 Transmission Mechanism 41 Control Roller 42 Second axis of rotation 43. Circumferential surface of the control roller 44 Control Spacing 45 Control slots 46 Rotary bearings 50 electric motors 51 Toothed belt 52 First toothed pulley 53 Second toothed pulley 60. Goods to be transported 61 First Transport Section 62 Second Transport Section 63 Traction devices 64 supports 65 Traction device drive unit 66. Delivery System 70 base 71 First base component 72 Second base component 73 Third base component 74 Sliding sleeve

Claims

1. A switch (10) for use with first and second transport sections (61; 62), wherein at least the first transport section (61) comprises two parallel, spaced-apart, continuously operating traction devices (63), wherein all traction devices (63) define a common transport plane, wherein, The switch (10) includes a switch arm (30) supported in a rotatable manner about a first axis of rotation (31), wherein the switch arm is guided in a linearly movable manner along the direction of the first axis of rotation (31), wherein the switch arm is capable of reciprocating between a first and a second end position, wherein the first axis of rotation (31) is oriented perpendicular to a transport plane, wherein the transport plane is arranged between two traction devices (63) of the first transport segment, wherein the switch arm (30) The switch arm (30) has a concavely curved steering surface (32) that is configured such that when the switch arm (30) is in the first end position, the transport object (60) can be transferred by means of the steering surface (32) from the first transport section (61) to the second transport section (62), and vice versa, wherein the switch arm (30) is completely positioned below the transport plane in the second end position, so that the transport object (60) can move along the first transport section (61) across the switch (10). The switch arm (30) is characterized in that it is driven to a single electric motor (50) via a transmission mechanism (40), such that the switch arm can move back and forth between the first and second endpoint positions in two degrees of freedom coupled by the transmission mechanism (40) solely by the drive of the electric motor (50).

2. The switch (10) according to claim 1. The transmission mechanism (40) is designed such that its linear movement with respect to the switch arm (30) in the first end position is self-locking along the first rotation axis (31).

3. The switch (10) according to claim 1. The transmission mechanism (40) is designed such that it forms an end stop in the second end position for the movement of the switch arm (30) along the first axis of rotation (31) toward the second end position.

4. The switch (10) according to claim 1. The electric motor (50) is manufactured as a stepper motor, which is in drive connection with the transmission mechanism via a toothed belt (51). The switch has a corresponding toothed belt drive, wherein the corresponding toothed belt drive is designed such that it causes a transmission ratio greater than 2.

5. The switch (10) according to claim 1. The transmission mechanism (40) includes a control roller (41) rotatably supported about a second axis of rotation (42), the control roller being in a rotational drive connection with the electric motor (50), where the control roller (41) extends at least partially along the second axis of rotation (42) with a constant cross-sectional shape, wherein the corresponding circumferential surface has a control pitch (44) relative to the second axis of rotation (42) that varies along its circumference.

6. The switch (10) according to claim 5. The control pitch (44) is at its maximum at the first end position, and the transmission mechanism (40) is designed such that its linear movement with respect to the switch arm (30) at the first end position is self-locking along the first rotation axis (31).

7. The switch (10) according to claim 5. The control pitch (44) is minimum at the second end position, and the transmission mechanism (40) is designed such that it forms an end stop at the second end position for the movement of the switch arm (30) along the first axis of rotation (31) toward the second end position.

8. The switch (10) according to claim 5. The switch arm (30) is supported on a separate slide (20) in a manner rotatable about the first axis of rotation (31), the slide (20) being guided in a manner rotatable in a direction along the first axis of rotation (31), and the control surface (22) of the slide being placed on the circumferential surface of the control roller (41).

9. The switch (10) according to claim 8. The control roller (41) has a control groove (45) or control protrusion in the region of the circumferential surface (43), the control groove or control protrusion extending spirally about the second axis of rotation (42), wherein the switch arm (30) is fixedly connected to a separate control arm (33), the control arm being coupled to the control groove (45) or the control protrusion at its free end.

10. The switch (10) according to claim 9. The slide (20) includes a base plate (21) arranged parallel to the transport plane, wherein the switch arm (30) and control arm (33) are arranged on opposite sides of the base plate (21).

11. The switch (10) according to claim 1. The first rotation axis (31) is arranged within 30% to 70% of the length of the turning surface along the direction of movement of the transport (60).

12. The switch (10) according to claim 11. The first rotation axis (31) is arranged within 40% to 60% of the length of the turning surface along the direction of movement of the transport (60).

13. A transport system (66) having first and second transport sections (61; 62) and a switch (10) according to any one of the preceding claims, wherein at least the first transport section (61) includes two parallel, spaced-apart, continuously operating traction devices (63), wherein all traction devices (63) define a common transport plane, wherein a first axis of rotation (31) is oriented perpendicular to the transport plane, wherein the transport plane is arranged between the two traction devices (63) of the first transport section (61).

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