CA3104192A1

CA3104192A1 - Cable-operated emergency switch

Info

Publication number: CA3104192A1
Application number: CA3104192A
Authority: CA
Inventors: Heiko WAND
Original assignee: K+S Minerals and Agriculture GmbH
Current assignee: K+S Minerals and Agriculture GmbH
Priority date: 2018-06-20
Filing date: 2019-06-14
Publication date: 2019-12-26
Also published as: WO2019242787A2; DE102018004854A1; WO2019242787A3; WO2019242787A9

Abstract

The invention relates to a cable-operated emergency switch (100) to be coupled to a cable (32) so that when the cable (32) moves along a movement path (41), an emergency switching signal can be triggered. Said cable-operated emergency switch comprises a coupling element (31) and a housing (29) with emergency switching triggering means (20) arranged therein and with an emergency switching element (22). The coupling element (31) is operatively connected to the emergency switching triggering means (20) so that the emergency switching element (22) can be switched to trigger the emergency switching signal my means of the movement of the emergency switching triggering means (20). The cable-operated emergency switch further comprises a warning switching triggering means (10) and a warning switching element (12), said warning switching triggering element being operatively connected to the warning switching element (12). A warning signal relating to the movement of the cable (32) can be triggered by means of the warning switching element (12) before the emergency switching signal is triggered.

Description

CABLE-OPERATED EMERGENCY SWITCH
The invention relates to a cable-operated emergency switch to be coupled to a cable, so that when the cables moves along a movement path an emergency switching signal can be triggered, comprising a coupling element and a housing with emergency switching triggering means arranged therein and with an emergency switching element, whereby the coupling element is operatively connected to the emergency switching triggering means, so that the emergency switching element can be switched to trigger the emergency switching signal by means of the movement of the emergency switching triggering means. The invention further relates to a safety device with a cable-operated emergency switch of this type, in particular to be arranged connected to a conveyor belt system.
Cable-operated emergency switches for example are arranged as shutdown devices at specific intervals along extended conveyor belt systems to shut down the system in case of an emergency.
Usually connected to the coupling element is a cable, which runs in both directions and extends alongside the conveyor system, and which allows shutting down the conveyor system from any point by pulling on the pull cable.
DIN EN 620 specifies guidelines for emergency stop switches with ripcord systems for ascending conveyors and systems, safety, and environmental requirements for stationary belt conveyors for bulk cargo. It requires that emergency stop switches with ripcord systems are arranged in a way so that the associated switching devices are actuated if the ripcord is pulled in any direction or tears. Further, ripcord systems must be designed so that the failure of only a single one of the springs tensioning the ripcord will trigger the connected switching devices.
Date Recue/Date Received 2020-12-17

2 The ripcord switch must be triggerable by the action of a horizontal force acting upon the pullcord of less than 125 Newton, in the center between two guide rings and perpendicular to the cable. The lateral movement of the rope must be less than 300 mm.
PRIOR ART
Known from DE 696 19 128 T2 is a cable-activated switching device that by means of a switch can interrupt the power supply to machines. Disclosed is that a horizontal displacement of a coupling element effects a rotation of switching triggering means, which in turn activates a switching element.
Due to a lever arrangement between the coupling element and a structure supporting the switching triggering means, a relatively small movement of the coupling element effects a comparatively large angular movement of the switching triggering means.
A further cable-operated emergency switch is known from DE 1 159 074. A cable being pulled activates a switching element that is activated by switching triggering means, which in turn shuts down a conveyor belt. It is further disclosed that a latching element latches the switching elements in an emergency switching position and that in addition to an emergency switching signal, a switching contact is provided to output an optical and acoustic signal. This facilitates determining whether the switching element has switched.
EP 2 043 117 A2 describes a quick-clamping device for a cable-operated switch, that can be used to detect the expansion and tension of a cable. A signal can be generated when the tension deviates from a nominal value range. Thus variations in the cable tension can be detected and remedied at an early stage.
Date Recue/Date Received 2020-12-17

3 DE 29 35 420 C2 discloses an electrical switching-off device, in particular a cable-operated emergency switching device. The cable-operated emergency switching device is coupled with a cable, so that when the cable moves along a movement path an emergency switching signal can be triggered, and comprises a coupling element and a housing, with emergency switching triggering means arranged therein, and with an emergency switching element, whereby the coupling element is operatively connected to the emergency switching triggering means, so that the emergency switching element can be switched to trigger the emergency switching signal by means of the movement of the emergency switching triggering means. It is further disclosed that switching elements are arranged in the housing and are activated by a cylinder. These switching elements may also be arranged distributed at various angular positions on the circumference of the cylinder.
The above-described cable-operated emergency switching device is intended to provide a higher level of safety due to its redundant design with several switches and the decoupling between the coupling element and the cylinder. However, due to the complex design with numerous components, the manufacture of the cable-operated emergency switching device is expensive and susceptible to failure during operation.
DISCLOSURE OF THE INVENTION
Consequently it is the objective of the present invention to provide a cable-operated emergency switch and a safety device embodied with a cable-operated emergency switch, which in a cost-effective and reliable manner ensure a smooth and in particular continuous operation of a conveyor belt system without unnecessary emergency shut-downs.
This objective is met on the basis of a cable-operated emergency switch according the preamble of claim 1 in connection with the characterising features as well as a safety device in accordance with Date Recue/Date Received 2020-12-17

4 claim 13. Further embodiments of the invention are described in the dependent claims.
The invention specifies that in addition to the emergency switching triggering means in combination with the emergency switching element there are provided warning switching triggering means and a warning switching element, whereby the warning switching triggering means are operatively connected to the warning switching element, and whereby the warning switching element can, with respect to the movement of the cable, trigger a warning signal before the emergency switching signal is triggered.
Issuing the warning signal allows carrying out cable readjustments or for example the removal of debris such as for example dropped conveyed goods, which put the cable under additional tension, before an emergency switching signal is triggered and the conveyer belt system is stopped. This allows achieving a higher delivery rate and a better economy of the conveyor system.
In an advantageous embodiment of the cable-operated emergency switch, the emergency switching triggering means and/or the warning switching triggering means are arranged on at least one cylinder.
This provides a particularly reliable and inexpensive switching means for activating the emergency switching element and/or the warning switching element at a precisely defined switching point.
Advantageously, the emergency switching triggering means is embodied as an emergency switching track and/or the warning switching triggering means is embodied as a warning switching track, whereby the warning switching track and/or the emergency switching track are embodied in the at least one cylinder. This facilitates a particularly space-saving and compact design of the cable-operated emergency switch.
Date Recue/Date Received 2020-12-17 Advantageously, the emergency switching track is of greater length than the warning switching track and/or the warning switching track is of greater depth than the emergency switching track. The warning switching track and the emergency switching track are embodied as indentations in the cylinder. In this, the length of the warning switching track and the emergency switching track is determined by the length of the indentation along the circumference of the cylinder. The respective depths of the warning switching track and the emergency switching track are determined by how far the indentation extends from the circumference of the cylinder in the direction towards the rotational axis, Le. how close the indentation approaches a rotational axis of the cylinder. The different lengths of the tracks facilitates a simple design, without the need for additional complex mechanisms for switching the emergency switching element or the warning switching element. Alternatively, providing a single track with various depths facilitates a very compact construction, in which the warning switching element and the emergency switching element are realized integrated in a so-called two-stage switch that is switchable in dependence on the various depths of the indentations in the cylinder.
In a further embodiment of the cable-operated emergency switch, the emergency switching triggering means and the warning switching triggering means are arranged on the at least one cylinder adjacently, joined, or nested within each other. This configuration simplifies the design. In addition, synergies and a reduced number of manufacturing steps during production of the cylinder can reduce manufacturing costs.
In a further embodiment of the cable-operated emergency switch, the cylinder is connected directly to the coupling element and in dependence on the movement path of the cable is rotatable about a common axis of rotation. In addition, starting from a center position of the coupling element, a switching path to an emergency switching point of the emergency switching triggering means is greater than a switching path to a warning switching point of the warning switching triggering means.
Date Recue/Date Received 2020-12-17 The direct coupling provides a simple and reliable solution with few component parts. This prevents any errors or malfunction due to gear ratios, levers, or play between component parts.
Advantageously the coupling element of the cable-operated emergency switch can be held in the center position by means of a spring. In particular, the cylinder may be operatively connected to the spring, so that the coupling element is retained in the center position. Thus the cylinder fulfills several functions, eliminating the need for additional component parts. Using a spring allows a simple readjustment and customization of the force that counteracts the cable tension or deflection with respect to the cable's movement. This prevents erroneous shutdowns due to cable tensions or cable deflections below a threshold value.
In a further preferred embodiment of the cable-operated emergency switch, a latching element is provided to engage and retain the emergency switching triggering means in an emergency switching position upon output of the emergency switching signal. Also provided is a return element for unlatching and returning to the center position. The latching element ensures that after triggering of the emergency switching signal and the associated shutdown of the conveyor belt system an inadvertent restart can be ruled out. Expediently, the return element ensures that the operation of the conveyor belt system is only possible after an intended return to the center position.
Alternatively, the warning switching triggering means, the emergency switching triggering means, and the latching element may be embodied in other shapes and designs that fulfill the required function, such as for example cams, pegs, tracks, hooks, etc.
Date Recue/Date Received 2020-12-17 The invention further relates to a safety device for a conveyor belt system with a cable and with a cable-operated emergency switch to be coupled to a cable, so that an emergency switching signal and a warning signal can be triggered in case of a movement of the cable along a movement path, and with a control module that is designed to issue a warning message when the warning signal is output and to stop the conveyor belt system when the emergency switching signal is output. Issuing the warning signal allows carrying out cable readjustments or the removal of foreign objects such as for example dropped conveyed goods, which increase the tension of the cable, before an emergency switching signal is triggered and the conveyor belt system is stopped. This leads to a higher production rate and efficiency of the conveyor system. Alternatively, the use of a control module can be foregone and a drive can be stopped or the conveyor belt system can be shut down by means of the emergency switching element. Moreover, the warning switching element can issue a warning signal directly.
Advantageously, the safety device is provided with a cable-operated emergency switch in an embodiment in accordance with the above-described characteristic features as a constituent component of the safety device.
PREFERRED EMBODIMENT EXAMPLE OF THE INVENTION
Further measures improving the invention are described in the following together with the description of a preferred embodiment example of the invention with the help of the figures. The figures show:
Fig. 1 shows a perspective view of a cable-operated emergency switch without the housing cover;
Fig. 2 shows a top view onto the open cable-operated emergency switch;
Date Recue/Date Received 2020-12-17 Fig. 3 shows lateral views of the section along the section line A-A of the cable-operated emergency switch of Fig. 2 with an emergency switching track and a warning switching track embodied on a cylinder as well as an emergency switching element;
Fig. 4 shows lateral views of the section along the section line B-B of the cable-operated emergency switch of Fig. 2 with the warning switching track embodied on the cylinder and a warning switching element;
Fig. 5 shows the cable-operated emergency switch in a center position, an emergency switching position, and a warning switching position;
Fig. 6 shows a portion of the emergency switching track with the emergency switching element in the center position and the emergency switching position;
Fig. 7 shows a lateral view of the cylinder with the emergency switching track and the warning switching track nested within each other;
Fig. 8 shows a schematic representation of a conveyor belt system with a safety device, comprising the cable-operated emergency switch as well as a control module.
Figs. 1 and 2 show in a perspective view and top view respectively a cable-operated emergency switch 100 with a cylinder 30, which is arranged in a housing 29 and on which are provided warning switching triggering means 10 embodied as a warning switching track 11 as well as emergency switching triggering means 20 embodied as an emergency switching track 21. A warning switching element 12 and an emergency switching element 22 are operatively connected to the warning switching track 11 and the emergency switching track 21 respectively. A coupling element 31 for accommodating a cable 32 is directly connected to the cylinder 30. The cylinder 30 and the coupling element 31 are movable about a rotational axis 34. Also provided Date Recue/Date Received 2020-12-17 in the housing 29 is a latching element 35 with a return element 36 coupled thereto.
Figs. 3 and 4 show a cross-sectional view of the cable-operated emergency switch 100 in a central position M. In this, a roller 37 of a switching lever 38 of the emergency switching element 22 is arranged centrally in the emergency switching track 21 and the warning switching track 11. Originating from the center position M, the switching path is the distance between the roller 37 and the warning switching point 43 or a distance between the roller 37 and the emergency switching point 44, respectively. A latching hook 39 of the latching element 35, which is subjected to the spring load of a latch spring 47, is in contact under load with a latching projection 40 of the cylinder 30. During a movement of the cable 32 along a movement path 41, the coupling element 31 and the cylinder 30 rotate about the axis of rotation 34. As is shown in Fig. 4, the warning switching element 12 with the roller 37 and the switching lever 38 are arranged centrally in the warning switching track 11. A
clockwise or anti-clockwise rotatory movement allows rotating the roller 37 with the switching lever 38 out of the warning switching track 11. Upon reaching the warning switching position W (see Fig. 5d) the roller 37 has reached a warning switching point 43 and the warning switching element 12 initiates a warning signal. In this, the latching hook 39 continues to rest upon the latching projection 40, so that no latching takes place and the cylinder 30 with the coupling element 31 can return to the center position M unimpededly. Consequently it is possible to detect a movement of the cable 32 that might indicate a maladjustment or a possible forthcoming emergency shutdown.
Measures can be undertaken to prevent this emergency shutdown without having to interrupt operations. A support 45 that is arranged on the housing holds the ends of the spring 33. The cylinder 30 and the coupling element 31 are movable about the rotational axis 34, whereby the cylinder 30 as well as the coupling element 31 are held in the center position M by means of the spring load of the spring 33. In case of a displacement of the coupling element 31 Date Recue/Date Received 2020-12-17 and rotatory movement of the cylinder 30 away from the center position M, the spring 33 will exert a restoring force directed towards the center position M.
Fig. 5 shows a schematic representation of the cable-operated emergency switch 100 and the cable 32, which on two ends is connected to a cable tension spring 42 and consequently is kept under tension. In Fig. 5a the coupling element 31 is in the center position M. In this, the force enacted by the tension springs 42 upon the coupling element 31 is of equal magnitude in opposing directions. A
warning switching position W according to Fig. 5d is reached as a result of a short displacement of the coupling element 31 caused by a movement of the cable 32. Also shown is the cable-operated emergency switch 100 in an emergency switching position N. In a first scenario according to Fig. 5b the cable 32 has broken on one side. As a result of the resulting one-sided pull of the cable tension spring 42 the coupling element 31 is pulled into the emergency switching position N. In a second scenario with an end-to-end intact cable 32 according to Fig. Sc, the emergency switching position N
is effected either by a decrease in tension on the one side and/or an increase in tension of the cable 32 of the cable-operated emergency switch 100. For example because of conveyed goods dropped onto the cable from a conveyor belt or due to temperature fluctuations and the accompanying expansion or contraction of the cable 32.
Figs. 6a and 6b show a portion of the cylinder 30 as viewed along the rotational axis 34, with the emergency switching track 21 in the center position M in Fig. 6a, and in the emergency switching position N in Fig. 6b. In this, the switching lever 38 with the roller 37 are rotated out of the emergency switching track 21 and are positioned at the emergency switching point 44 on the cylinder 30. As a result of the movement of the switching lever 38, the emergency switching element 22 (not shown here) is switched and an emergency switching signal is output. In this position, the latching hook 39 has jumped and latched in front of or behind a projecting edge 46 of the latching projection 40, which prevents a return movement to the center position M. In this, the latching hook 39 rests upon the cylinder 30 under the applied spring load Date Recue/Date Received 2020-12-17 of the latch spring 47. The emergency switching position N described here is reached by a clockwise or anti-clockwise rotation. An advantage of this arrangement with an emergency switching track 21 and a latching projection 40 is that even in the case of continued rotation or over-rotation of the cylinder 30, the switching lever 38 remains in its position and the latching hook 39 will catch at the projecting edge 46 when the cylinder 30 is rotated back. Consequently, no damage to components can occur and the emergency switching signal is output continuously.
Fig. 7 shows a cylinder 30 with the warning switching track 11 and emergency switching track 21 arranged nested within each other therein. A clockwise or anti-clockwise rotational movement causes the switching lever 38 with the roller 37 to be swung out of the warning switching track 11 into the emergency switching track 21, which, upon reaching the warning switching point 43, outputs the warning signal. Continued rotational movement to the emergency switching point 44 issues the emergency switching signal.
Shown in Fig. 8 is a safety device 110 of a conveyor belt system 120, comprising a conveyor belt 121, conveyor belt rollers 122, and a conveyor belt drive 123. The safety device 110 comprises the cable-operated emergency switch 100 with the cable 32 connected thereto as well as a control module 111, which is connected to the cable-operated emergency switch 100 via a signal cable 112 to receive the warning signal and the emergency switching signal. The control module 111 further is connected to the drive 123 as well as to signal means 113. Upon receiving the emergency switching signal, the control module 111 effects a deactivation of the drive 123 as well as the output of the emergency switching signal by the signal means 113. Upon receiving a warning signal, the control module 111 sends a warning message to a control center that is not shown here.
Date Recue/Date Received 2020-12-17 List of reference labels:
Warning switching triggering means 11 Warning switching track 12 Warning switching element Emergency switching triggering means 21 Emergency switching track 22 Emergency switching element 29 Housing Cylinder 31 Coupling element 32 Cable 33 Spring 34 Rotational axis Latching element 36 Return element 37 Roller 38 Switching lever 39 Latching hook Latching projection 41 Movement path 42 Cable tension spring 43 Warning switching point Date Recue/Date Received 2020-12-17 44 Emergency switching point 45 Support 46 Projection edge 47 Latch spring M Center position N Emergency switching position W Warning switching position 100 Cable-operated emergency switch 110 Safety device 111 Control module 112 Signal cable 113 Signal means 120 Conveyor belt system 121 Conveyor belt 122 Conveyor belt rollers 123 Conveyor belt drive Date Recue/Date Received 2020-12-17

Claims

1. A cable-operated emergency switch (100) to be coupled to a cable (32), so that when the cable (32) moves along a movement path (41), an emergency switching signal can be triggered, comprising a coupling element (31) and one housing (29), with emergency switching triggering means (20) and with an emergency switching element (22) arranged in said housing, whereby the coupling element (31) is operatively connected with the emergency switching triggering means (20), so that by means of the movement of the emergency switching triggering means (20) the emergency switching element (22) can be switched to trigger the emergency switching signal, characterized in that further provided are warning switching triggering means (10) and a warning switching element (12), whereby the warning switching triggering means is operatively connected to the warning switching element (12), and whereby the warning switching element (12) can trigger a warning signal prior, relative to the movement of the cable (32), to triggering the emergency switching signal.

2. The cable-operated emergency switch (100) of claim 1, characterized in that the emergency switching triggering means (20) and/or the warning switching triggering means (10) are arranged on at least one cylinder (30).

3. The cable-operated emergency switch (100) of claim 1 or 2, characterized in that the emergency switching triggering means (20) is embodied as an emergency switching track (21) and/or the warning switching triggering means (10) is embodied as a warning switching track (11).
Date Recue/Date Received 2020-12-17

4. The cable-operated emergency switch (100) of claim 3, characterized in that the warning switching track (11) and/or the emergency switching track (21) are embodied as indentations in the at least one cylinder (30).

5. The cable-operated emergency switch (100) of claim 3 or 4, characterized in that the emergency switching track (21) is of greater length than the warning switching track (11) and/or that the warning switching track (11) is of greater depth than the emergency switching track (21).

6. The cable-operated emergency switch (100) of one of the preceding claims, characterized in that the emergency switching triggering means (20) and the warning switching triggering means (10) are arranged on the at least one cylinder (30) adjacently, joined, or nested within each other.

7. The cable-operated emergency switch (100) of one of the preceding claims, characterized in that originating from a central position (M) of the coupling element (31), a switching path to an emergency switching point (44) of the emergency switching triggering means (20) is greater than a switching path to a warning switching point (43) of the warning switching triggering means (10).

8. The cable-operated emergency switch (100) of one of the preceding claims, characterized in that the cylinder (30) is connected directly to the coupling element (31), and in dependence on the movement path (41) of the cable (32), they are rotatable about a common axis of rotation (34).
Date Recue/Date Received 2020-12-17

9. The cable-operated emergency switch (100) of one of the preceding claims, characterized in that the coupling element (31) can be held in the center position (M) by means of a spring (33).

10. The cable-operated emergency switch (100) of one of the preceding claims, characterized in that the cylinder (30) is operatively connected to the spring (33), so that the coupling element (31) is held in the center position (M).

11. The cable-operated emergency switch (100) of one of the preceding claims, characterized in that a latching element (35) is provided to engage and retain the emergency switching triggering means (20) in an emergency switching position (M) when the emergency switching signal is issued upon output of the emergency switching signal.

12. The cable-operated emergency switch (100) of one of the preceding claims, characterized in that a return element (36) is provided for unlatching and returning to the center position (M).

13. Safety device (100) for a conveyor belt system (120) with a cable (32) and with a cable-operated emergency switch (100) to be coupled to the cable (32) in accordance with one of claims 1 to 12, so that during a movement of the cable (32) along a movement path (41) initially a warning signal can be triggered and upon further movement an emergency switching signal is triggered, and with a control module (111), which is designed to issue a warning message when the warning signal is triggered and to stop the conveyor belt system (120) when an emergency switching signal is triggered.
Date Recue/Date Received 2020-12-17