JP2017516725A - Belt conveyor and viscoelastic damping device and method for damping a conveyor belt - Google Patents

Abstract

A viscoelastic damping device, and a belt conveyor system that uses a viscoelastic damping device to reduce belt vibration, and a method for damping a change in belt speed. One form of viscoelastic damping device includes a low friction conveying path element attached to a viscoelastic pad that is rigidly attached to a stationary conveyor framework at various locations along the length and width of the conveyor system. Variations in the speed of the conveyor belt supported and advanced along the low friction conveying path element are damped by the viscoelastic damping device. In some configurations, magnetic belts are used to tighten the conveyor belt to the damping device to increase effective damping. [Selection] Figure 1

Description

  The present invention relates generally to power-driven conveyors for conveying articles, and in particular to conveyor systems that use viscoelastic damping devices and methods for smoothing the movement of conveyor belts.

  One purpose of a conveyor, such as a conveyor belt, is to smoothly transport products or people through larger equipment or from one point to another in manufacturing, logistics, or transport operations. The smooth linear motion of the conveyor is important in many applications, for example, transporting passengers, manufacturing extrudates, and transporting unstable products that tend to tilt in an upright position. However, due to the many variables, the movement of the conveyor belt is not smooth. These variables include, but are not limited to, belt drivetrain variations, conveyor belt resonances, resonances of other connected systems, and variable loads caused by people walking on the belt surface. . Variations and resonances affect the forward movement of the conveyor belt by causing speed changes, ie acceleration. Such speed changes, i.e. accelerations, can cause passengers to collide, cans or bottles to fall, or the quality of a continuous manufacturing process to be reduced. This problem is particularly noticeable in long conveyor systems. This is because the accumulated elasticity of the long belt makes it difficult to control the dynamic movement of the belt, which is mainly seen in the belt movement direction of the moving belt. In the means for transporting people, for example, when a passenger walks around or moves on a belt, the weight of the person's moving foot creates a periodic load that acts as a forcing function. The spring constant of the long belt allows the belt on the belt to stretch and compress to an extent that passengers on the belt are easily noticeable and undesirable. The dynamic movement of the belt is a problem. In this example, the weight of the moving foot is the cause of the forcing function, but a long belt is more elastic and more likely to resonate. Therefore, there is a need to move the belt conveyor smoothly.

  One form of conveyor system embodying features of the invention includes a conveyor belt supported in a frame. The belt advances at the belt speed in the belt moving direction along the upper traveling portion. The viscoelastic damping device contacts the conveyor belt at a position along the upper running section. The viscoelastic damping device includes a support surface that contacts the conveyor belt. The viscoelastic damping material attached to the support surface and to the frame is placed in shear as the conveyor belt advances over the support surface so that changes in belt speed are mitigated by the viscoelastic damping device.

  In another aspect, a viscoelastic damping device embodying features of the present invention includes a support element having a support surface in contact with an advancing conveyor belt and an opposite surface. A damping pad made from a viscoelastic damping material attached to the support element is placed in a sheared state as the conveyor belt in contact with the support surface advances along the support element.

  In another aspect, a method for dampening a conveyor belt includes: (a) advancing the conveyor belt along an upper running portion; and (b) lined with a viscoelastic material along the upper running portion of the conveyor belt. Contacting the support surface with the conveyor belt.

  These aspects and features of the present invention will be better understood with reference to the following description, appended claims and accompanying drawings.

FIG. 1 is a cross-sectional view of an upper traveling portion of a conveyor system embodying features of the present invention including a viscous damping device. FIG. 2 is a cross-sectional view of a conveyor system as in FIG. 1 including a viscous damping device that is tightened. 3A and 3B are front views of one form of inertial viscosity damping device useful in a conveyor system such as that of FIG. FIG. 4 is an isometric view of another form of conveyor system embodying features of the present invention, including an accelerometer embedded in a moving conveyor belt. FIG. 5 is a block diagram of the controller of the conveyor system of FIG. 6 is a top view of a conveyor system as in FIG. 4, further illustrating a linear attenuator operated in a closed loop system, and FIG. 6A is an enlarged view of the linear attenuator of FIG. 7 is a top view of a conveyor system as in FIG. 4, further illustrating a magnetic clamp dampener operated in a closed loop system, and FIG. 7A is an enlarged view of the magnetic clamp dampener of FIG. is there.

  A portion of the upper run of the belt conveyor system embodying features of the present invention is shown in FIG. The underside of the conveyor belt 10 is supported by a support element 100 that functions as a transport path element. A viscoelastic pad 102 is sandwiched between the transport path 100 and the fixed transport frame 104. The conveyance path 100 has a flat upper support surface 101 and is made of a low to medium friction material such as, for example, UHMW or nylon. High friction materials may be used if appropriate for the application. The transport path 100 comprises a set of laterally spaced parallel wear strips having a sliding floor continuous across the entire width and length of the upper running section, an upper sliding support surface 101 extending the length of the upper running section, Alternatively, it can be configured as a set of support element segments between fixed wear strip segments 106 that are not attached to the viscoelastic pad but are firmly attached to the frame 104. If a sliding floor, parallel wear strips that extend the length of the upper running section, chevron wear strips, or other wear strips that can support belts and conveyed articles are used, the support surface should be made of low friction material. Can be made. If the transport path is segmented along its length into wear strip segments with and without viscoelastic damping pads, the support surface of the damping segment can be made from a high friction material or a serrated high friction surface Can have. The conveyance path 104 is attached to the upper surface of the viscoelastic pad 102 by, for example, adhesive bonding, co-molding, co-extrusion, or mechanical attachment. The bottom surface of the viscoelastic pad 102 is coupled to the fixed conveyor frame 104. Alternatively, the upper support surface may be formed on the upper surface of the viscoelastic pad itself.

  As the conveyor belt 10 advances along the upper runner in the belt movement direction 108 (goes out in front of the page in FIG. 1) and slides along the transport path 100, the viscoelastic pad 102 is belted and transported. Due to the article, it is placed in shear and some compression. Vibrations and pulsations during belt speed are transmitted to the viscoelastic material via a transport path 100 to which the viscoelastic material is firmly attached. Vibration energy is dissipated as heat. The wear strip 100 and viscoelastic pad 102 together form a damping device 110 that is rigidly attached to the frame 104.

  Another form of viscoelastic damping is shown in the conveyor system of FIG. In this form, a ferrous material such as a metal mass 112 is molded, embedded or mounted on the conveyor belt at spaced locations along the length and width of the conveyor belt 10. Permanent magnets or electromagnets 114 attached below the damping device 110, or permanent magnets or electromagnets (114 ') attached to both sides of the damping device 110 attract the ferrous metal mass 112 as indicated by arrows 115. And tighten the belt against the damping device 110 to form a clamping means. The magnets may be arranged continuously or intermittently along the length of the upper running part. By tightening the conveyor belt 10 to the damping device 110, the effect of transmission of linear high frequency acceleration from the advancing belt to the viscoelastic pad 102 is enhanced. Accordingly, the damping due to tightening may be more effective than the passive damping described with respect to FIG. As an alternative clamping means, a permanent magnet may be introduced into the belt instead of a ferrous metal mass, and the magnet in the conveyor framework may be replaced with an iron material attached to the belt magnet.

  Another form of attenuation device is shown in FIGS. 3A and 3B. FIG. 3A shows a damping device 116 that provides both viscous and inertial damping. A high density material 118 such as steel or copper is sandwiched between the viscoelastic pad 102 and the transport path 100. In FIG. 3B, the high density material 120 is embedded in the viscoelastic pad 102 'itself. The added mass of the high density material adds inertial damping to the viscous damping provided by the viscoelastic material. When used with a magnetic clamping device, the high density material 118, 120 may be a non-ferrous material.

  Another form of conveyor system embodying features of the invention is shown in FIG. The conveyor is shown in this example as a conveyor belt 10 supported by a transport path 60 and transports articles 12 through step 11 in the transport direction 13 on the outer transport surface 22 along the transport path segment 15 of the belt's endless transport path. To do. Articles are conveyed out of the conveyor belt at the end of the transport path. After turning around the drive sprocket 18, the conveyor belt 10 follows the return segment 17 on its return path and around the idle sprocket 20 to the transport path segment 15. Both the drive sprocket and the idle sprocket are attached to a shaft 68 (only the idle shaft is shown in FIG. 4).

  One or more accelerometers 24 embedded in the belt 10 determine dynamic belt movement measurements, such as velocity or acceleration changes. The term “embedded” is used in a broad sense to encompass any introduction of an accelerometer into the conveyor. An example of an embedded accelerometer is that the accelerometer is mounted on or in the advancing conveyor, molded therein, inserted therein, laminated therein, Including being welded to it, joined to it, or otherwise securely connected to it. The accelerometer 24 is, for example, a single axis accelerometer that senses local belt acceleration components along the x-axis parallel to the transport direction 13; A two-axis accelerometer that senses acceleration components along the axis; or senses three orthogonal components of local acceleration along the z-axis, for example, along the x-axis and y-axis and through the thickness of the conveyor belt Can be a three-axis accelerometer. For most applications, belt acceleration along the x-axis will be the most interesting and more controllable belt acceleration, but acceleration along the other axes may be equally interesting. For example, an accelerometer that senses acceleration along the z-axis or even along the x-axis can be used to detect the impact of articles falling on the conveyor belt. Examples of accelerometer technology include piezoelectricity, piezoresistive, and capacitive. To save space, accelerometers based on microelectromechanical systems (MEMS) are useful. In FIG. 4, the figure shows a modular plastic conveyor belt loop composed of a row of hinged modules, but the accelerometers 24 are regularly spaced along the length of the belt and across its width. .

  As shown in FIG. 5, each accelerometer 24 is connected to a logic circuit 28 of the conveyor belt 10. Each logic circuit may be implemented by a programmable microcontroller or by hardwired logic elements. Conventional signal conditioning circuit elements such as buffers, amplifiers, analog to digital converters, and multiplexers may be placed between the accelerometer and the logic circuit. The logic circuit may also include a unique address or other identification to correlate each accelerometer response with a particular position on the conveyor belt. The identification and accelerometer measurements can be stored in one or more memory elements 29. The accelerometer measurement (1, 2, or 3 acceleration components) is converted into a measurement signal 30 that is transmitted remotely by a transmitter 32. The transmitter includes a conductive contact 40 on the outer side of the belt 10, via a wireless communication link 36 via an antenna 34, or in a conveyor structure brush 42 along the side of the belt, as in FIG. It may be a wireless RF transmitter that transmits wirelessly via an ohmic connection 38 between the two. A receiver 33 may also be connected to the logic circuit to receive commands and control signals from a remote controller 44, i.e. a controller not located on or within the conveyor belt. Other transmitter-receiver technologies such as optical or infrared may be used. All of the components embedded in the belt may be powered by a power source 45 that is housed together in a recess in the belt, such as one or more accumulators. Alternatively, the power source 45 may be an energy acquisition device that acquires energy from conveyor vibration or refraction, thermal gradients, or other energy generation effects inherent in the process or transport. Alternatively, the embedded power supply 45 may be powered by dielectric or by wireless charging when recirculating through an external charging device 49 as in FIG.

  The remote receiver 46 receives the measurement signal 30 from the receiver 33 embedded in the conveyor belt via the antenna 48 via the wireless communication link 36 or via the ohmic connection 38. The receiver 46 sends a measurement signal to the remote controller 44. A transmitter 47 connected between the controller 44 and the antenna 48 or ohmic connection 38 may be used to send command and control signals to the accelerometer circuit supported on the belt. An operator input device 50 connected to the controller 44 may be used to select an accelerometer or alarm setpoint or data to be displayed. The controller 44 may also be used to stop or control the speed of the motor 52 that drives the main drive sprocket 18 or to activate a clamp dampening device 64 that acts on the conveyor belt itself. A video display 54 may be used to monitor system operating conditions and settings, or display alarm conditions. Also, a more clearly visible or audible alarm 56 may be used by the controller to warn of irregularities in the process. The controller may be a programmable logic controller, a laptop, a desktop, or any suitable computer device.

  Other sensors 62 can be used instead of or in addition to the belt-mounted accelerometer. Examples of sensors with sufficient resolution to sense the dynamic movement of a moving conveyor belt include tachometers, belt-mounted strain gauges, and laser Doppler velocimeters.

  6 and 6A show the closed loop viscoelastic damping applied to the conveyor belt 10 at a location along the transport path 15. The acceleration measurement determined by the accelerometer 24 is communicated to the controller 44 via the communication link 36. In response to the acceleration measurement, the controller activates a viscoelastic damping device 72 that acts directly on the conveyor belt 10. An actuator 74 associated with the damping device 72 receives the control signal 61 from the controller to increase or decrease or otherwise adjust the pressure applied by the damping device to the outer surface 22 of the conveyor belt 10. The linear attenuator 72 is in the form of a movable clamp pad, such as the pad 110 of FIG. 1, forms a clamping means with the upper sliding surface 59 of the transport path 60 and the actuator, and applies the clamping force to the belt 10. Attenuate unwanted acceleration. Similar to the modular plastic conveyor belt and transport path, the clamp pad may be made from a viscoelastic polymeric material. The attenuation device can be installed intermittently along the transport path segment 15. In this example, the viscoelastic material is in the linear damping device clamp pad 72 above the belt. If the transport path 60 is made from or attached to a viscoelastic material, the clamp pad 72 may be made without a viscoelastic damping material. Alternatively, the viscoelastic material may be present in both the transport path 60 and the clamping device 72.

  7 and 7A show a viscoelastic damping system similar to that of FIG. 2 that uses magnetic or electromagnetic forces to clamp the belt against the damping device. In this form, the belt 10 ', the transport path 60', or both are made from a viscoelastic material. The clamping force is obtained using a permanent magnet or electromagnet 73. Permanent magnets or electromagnets 73 outside the belt act on the iron or other magnetically attractable material or magnet inside the belt 10 'at one or more positions across the width of the belt to provide the belt and transport path. A clamping force is generated during Alternatively, ferrous or other magnetically attractive material outside the belt acts on the permanent magnet or electromagnet inside the belt to generate a clamping force. Controller 44 adjusts the position of the electromagnetic force or fixed attractive material to obtain the desired damping pressure.

  Although the present invention has been described in detail with reference to exemplary forms, other forms are possible. For example, the attenuator control may be operated in a manner that is on / off or otherwise adjusted. Also, the attenuation can vary linearly or non-linearly with belt speed.

Claims (21)

Frame,
A conveyor belt supported in the frame and advanced at a belt speed in the belt movement direction along the upper running portion;
A viscoelastic damping device in contact with the conveyor belt at a position along the upper running section,
A viscoelastic damping comprising a support surface in contact with the conveyor belt, and a viscoelastic damping material attached to the support surface and the frame such that the conveyor belt is placed in a sheared state as it advances over the support surface In a conveyor system including a device,
Conveyor system characterized in that the change in belt speed is mitigated by the viscoelastic damping device.   2. A conveyor system according to claim 1, further comprising clamping means for clamping said conveyor belt against said support surface of said viscoelastic damping device.   3. A conveyor system according to claim 2, wherein said clamping means includes a magnet in or on said conveyor belt, said magnet attracting iron material outside said conveyor belt, close to said viscoelastic damping device. Conveyor system characterized by exerting force.   3. A conveyor system according to claim 2, wherein the clamping means includes a magnet disposed near the viscoelastic damping device, the magnet being in a ferrous material disposed in or on the conveyor belt. A conveyor system characterized by exerting a suction force.   5. A conveyor system according to claim 4, further comprising a controller, wherein the magnet is an electromagnet, the magnetic force of which is selectively adjusted by the controller.   3. The conveyor system according to claim 2, wherein the clamping means includes a sliding surface that contacts the conveyor belt from above or below, and an actuator, and the viscoelastic damping device is the sliding of the conveyor belt. Disposed on the opposite side of the surface, and the actuator is coupled to the viscoelastic damping device to clamp the conveyor belt between the sliding surface and the viscoelastic damping device, Conveyor system.   7. A conveyor system according to claim 6, further comprising a controller coupled to the actuator for adjusting a clamping pressure of the clamping means relative to the conveyor belt.   3. The conveyor system of claim 2, further comprising a controller and a sensor for sensing dynamic movement of the conveyor belt and sending a sensor signal to the controller, the controller being configured by the clamping means. A conveyor system, characterized in that a clamping signal is sent to the clamping means to regulate the pressure exerted on the conveyor belt.   The conveyor system according to claim 1, wherein the support surface is formed on the viscoelastic damping material.   The conveyor system of claim 1, wherein the viscoelastic damping device includes a support element attached to the viscoelastic damping material, and the support surface is formed on the support element. system.   The conveyor system according to claim 1, wherein the support surface is formed on a conveyance path that supports the conveyor belt along the upper running portion.   The conveyor system according to claim 1, wherein the viscoelastic damping device further comprises a high density material having a higher density than the viscoelastic damping material.   13. A conveyor system according to claim 12, wherein the high density material is disposed between the support surface and the viscoelastic damping material.   13. A conveyor system according to claim 12, wherein the high density material is embedded in the viscoelastic damping material.   The conveyor system according to claim 1, comprising a plurality of viscoelastic damping devices disposed along the length of the conveyor belt and across the width of the conveyor belt in the upper running section. . In the viscoelastic damping device,
A support element having a support surface and an opposite surface in contact with the advancing conveyor belt;
A damping pad made from a viscoelastic damping material and attached to the opposite surface of the support element such that a conveyor belt in contact with the support surface is placed in shear as it advances along the support element. A viscoelastic damping device comprising a damping pad.   17. The viscoelastic damping device according to claim 16, wherein the viscoelastic pad is attached to the support element by adhesive bonding, co-molding, co-extrusion, or mechanical attachment.   17. Viscoelastic damping device according to claim 16, characterized in that the support surface is made of a frictional material lower than the viscoelastic material. In a method for damping a conveyor belt,
Advancing the conveyor belt along the upper running section;
Contacting said conveyor belt with a support surface lined with a viscoelastic material along said upper running portion of said conveyor belt.   20. The method of claim 19, further comprising clamping the support surface lined with the viscoelastic material against the conveyor belt with a clamping pressure. The method of claim 20, wherein
Sensing dynamic movement of the conveyor belt as the conveyor belt advances along the upper runner;
Adjusting the clamping pressure in response to the sensed dynamic movement.

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