Apparatus for stopping cutting disc

Abstract

The machine operator holds the chicken carcasses to a circular saw or places the casting on a cutting grindstone. The large risk of the opponent can be minimized with a controllable (about 10 ms) wheel stop mechanism that is optically triggered when the glove-worn finger enters the hazard zone. (One option uses a conductive glove trigger). The electromagnets release a strong spring that is mechanically linked with the opposed brake shoes forcing the opposed brake shoes against both sides of the brake disc. The brake disc and the cutting wheel share a shaft, but are located in different compartments. Comprising accident reporting through a network.

Description

Technical Field

[0001] For cutting machines with motor-driven cutting discs or wheels, such as circular saws or grinding wheels, the present invention provides a device for quickly stopping the cutting wheel's rotation. The stopping disc can protect the operator's hands from trauma. More generally, the present invention describes a machine in which a detector for a hazardous situation is connected to a disc brake device that can quickly stop an axis.

[0002] definition:

[0003] "Brake pause" describes the process used in the present invention to quickly stop the cutting disc or wheel.

[0004] For the purposes of this document, "quickly" or "quickly" is defined as "a total dwell time of less than 20 milliseconds." The specified times are given by way of example. Longer time intervals can be provided by the same mechanism.

[0005] A "circular saw" or "disc saw" describes a rotatable disk carrying a cutting edge, which may be a knife edge or may have circumferential teeth, for cutting an item into portions. Such machines and cutters are widely used in meat or poultry processing plants to separate carcasses into portions.

[0006] A "cutting wheel" is a self-sharpening wheel that is typically thin and includes reinforcing fibers. Background Art

[0007] Cutting wheels, including circular saws or disc saws, are widely used in industry to cut wood or plastic, and in the food industry to dismember carcasses. Unlike woodworking table saws, the entire disc may be exposed. Operators using disc saws in meat and poultry processing plants continue to be at risk of significant trauma to their hands, a risk that has been identified through the use of a 2024-01-15 last downloaded 2024-01-15 Video presentation (https: / / www.youtube.com / watch?v=KQyc65T50pY) The disc saw equipment described below can help reduce the danger.

[0008] Existing technology

[0009] The applicant has previously disclosed optical monitoring devices of this general type within cutting machines; for example in WO2016032345 and WO2023287304.

[0010] Murakami in US 2010-011926 discusses optical detection, but there is no equivalent mechanism for pausing the blade of a circular saw.

[0011] Gass, in US20170312837, describes conductive detection of glove proximity for circular saws. All stopping options are applied to the saw blade. One stopping option uses pyrotechnics.

[0012] Purpose of the Invention

[0013] An object of the present invention is to provide an apparatus and a method for quickly stopping a cutting wheel in response to an event that could cause hand trauma to an operator. The event could be optical detection of a hand approaching the cutting wheel. Summary of the Invention

[0014] In a first broad aspect, the present invention provides a hazard response device included in a disc cutter; this type of cutter has a motor and a rotatable cutter shaft supported by a frame by means of bearings, the frame fixedly supporting the cutting disc in a working area, wherein the cutter shaft also fixedly supports a discrete brake disc having sides and arranged in a space between a set of facing brake pads mounted on the frame; the hazard response device is adapted to, when in use, cause a first actuator to respond to a detected hazard by releasing energy stored in a spring, whereupon movement of the spring causes a linkage of at least one movable brake pad to press the pad against the side of the brake disc, thereby generating friction during the braking action and rapidly stopping the cutter shaft and cutting disc within a controlled period of time.

[0015] Preferably, the brake disc is supported from the cutter shaft in a compartment separate from the working area.

[0016] Alternatives to cutting discs or wheels are selected from a range including: cutting wheels with blades, cutting saws with teeth around the edge, and grinding or cutting wheels.

[0017] Preferably, the first actuator is selected from the range comprising a reversibly closed magnetic circuit and an electromagnetic trip device acting on an over-centre latch, said first actuator causing a rapid release of energy to the linkage when activated.

[0018] Preferably, the linkage comprises a brake arm pivotally connected to the spring and fixedly linked to a rotatable stub axle supported by the frame; the stub axle is in turn fixedly linked to the movable brake pad.

[0019] Preferably, recovery of the energy stored in the spring is provided by a prime mover selected from the range comprising an electric motor, a hydraulic piston and a pneumatic piston, thereby returning the cutter to a safe and stoppable condition before the cutter is used.

[0020] In a first option, the cutter shaft is driven directly by the motor.

[0021] In a second option, the cutter shaft is indirectly driven by a flexible drive selected from the range consisting of a belt drive and a synchronous belt drive, operatively coupling the cutter shaft to another shaft driven by a motor.

[0022] In a second broad aspect, a monitoring device capable of detecting an unsafe condition in use includes a camera and a lens capable, when in use, of forming at least one image of a danger volume including a preset area around a cutting disk, and detecting an image of an object having a preset distinctive appearance within the danger volume, and if detected, causing a first actuator to perform an action.

[0023] Preferably, the detected image is distinguished from the background by an image analysis device receiving the image from the camera, and the distinctive appearance is selected from a range of color characteristics including blue gloves, green gloves, yellow gloves, red gloves, fluorescent gloves and infrared fluorescent gloves to be worn by the operator.

[0024] In one option, the monitoring device comprises a device capable of detecting electrical contact between a conductive glove worn by the operator and wired to a sensing member within the device and a portion of the disc cutter comprising the cutting disc; the contact causing the first actuator to perform an action.

[0025] In a subsidiary aspect, the monitoring device comprises evaluation means for evaluating the time elapsed after the detection until the cutting wheel is stopped, and preventing the disc cutter from being used if the evaluated time exceeds a predetermined limit.

[0026] On the other hand, the monitoring device capable of detecting unsafe conditions during use also includes a second actuator; the second actuator includes a digital accident reporting system, which is configured to prepare an accident report and transmit the detailed accident report to the server via a network when the system is caused to respond to a hazard.

[0027] Preferably, the controlled time period of the braking action itself is in the range from 2 to 15 milliseconds.

[0028] Notes:

[0029] The description of the invention provided herein is given purely by way of example and should not be construed in any way as limiting the scope or extent of the invention. In particular, reference to "circular saw" or "cutting wheel" is made by way of example only to illustrate the invention, which is applicable to other rotatable cutting machines. Reference herein or in the claims to reference numerals in the accompanying drawings is non-limiting.

[0030] The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation.

[0031] Throughout this specification, unless the context requires otherwise, the word "comprise" and variations such as "comprising" and "containing" will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. Each document, reference, patent application or patent cited herein is expressly incorporated herein by reference in its entirety.

[0032] Reference to material or information cited in this document should not be taken as an admission that the material or information is within the common general knowledge or as being known in New Zealand or any other country. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 An oblique view of the standalone machine showing the active area and the monitoring extension above it for the two-axis version.

[0034] Figure 2 is a schematic diagram of the cutter shaft.

[0035] Figure 3 This is a conceptual diagram of a braking mechanism involving an electromagnet.

[0036] Figure 4 It is a schematic diagram from behind of the spring, its frame and the brake mechanism.

[0037] Figure 5 Viewed from the front at an angle, detail of the brake pads against the brake disc is shown.

[0038] Figure 6 This is a front view of the Optima brake disc.

[0039] Figure 7 is the section through the resilient mounting for the brake disc.

[0040] Figure 8 (On page 2 / 5) is a schematic diagram of the second embodiment (network) connection. DETAILED DESCRIPTION

[0041] First embodiment

[0042] This two-axis machine mimics existing disc saws used to divide poultry carcasses into two or more parts, while increasing safety. Whenever an emergency stop is required, the machine is adapted to quickly and non-destructively brake the cutting disc to a stop. As an operator safety measure, a monitoring device is included for detecting events that require the cutting disc to stop, which are likely to be related to the operator's hand movement. This specification describes a complete or integrated machine with a cutting wheel or cutting disc. There is a first actuator, which includes a device within the machine for stopping the cutting wheel, and a second optional actuator, which includes a networked activity reporting member.

[0043] Poultry disc cutting machine overall layout:

[0044] See also Figure 1 . The stand-alone poultry disc cutter 100 has a cutting disc including a cutting wheel 107 located within an open working volume or space 102. A shroud 108 conceals the rotary drive or cutter shaft 201 leading to the cantilevered blade. The cutter shaft is supported by bearings within the machine. The blade is fixed in place within the machine and is arranged at a height convenient for a standing operator (not shown). Typically, the operator manually holds the carcass before and during the cutting process. Passive guide rods 106 are commonly used in machines of this type to help guide the blade to and from the poultry carcass and to support the carcass against the forces exerted by the cutting action at the rotating blade edge.

[0045] The operator has a series of control buttons 105 for starting and normally stopping the machine. There is a status display 104. Support legs mounted on the floor are shown as 103, and within the working area 102 there is a splash guard or protective shield 109 for the cutting wheel 107.

[0046] Compartment:

[0047] Unlike some prior art, braking is not applied to the cutting wheel 107 itself. The working volume 102 including the blades can be considered an open compartment. Panel 208 ( Figure 2 ) isolates the environment of the brake compartment 200 to the left of the guard 108 from the space 102 so that (1) debris from sawing (such as fat) is kept away from the friction brake, (2) cleaning fluid is kept outside the interior of the machine, (3) the operator is protected from moving parts, including the drive of the cutter shaft and any components that are forcibly energized during any braking action, and (4) the brake compartment 200 can be heated to prevent condensation as some of the working environment and some of the workpiece are cooled.

[0048] Triggering event:

[0049] In addition to a power loss or normal stop in response to an operator command at the "Stop" button 105, the machine is capable of quickly executing a braking stop involving the cutting disc in response to triggering events including:

[0050] a. Visual monitoring detection by a machine vision device (see below) which, according to pre-defined settings, identifies when the operator's gloved hand is too close to the cutting wheel. This initiates a brake pause. See below.

[0051] b. Electrical contact detection (optional): If the operator's hand, wearing a conductive glove, makes electrical contact with the cut-off wheel. Both visual and electrical sensing can coexist. Requires a wired connection from the operator's hand to the machine. See below.

[0052] c. The internal or external power supply of the whole machine is interrupted.

[0053] d. The self-monitoring of the machine's braking performance detected a fault.

[0054] The triggering events that initiate the brake pause are OR-connected. During normal operation, the energy storage device, a powerful spring, is kept compressed by an electromechanical device, which is either a directly held electromagnet armature (first embodiment) or a retaining finger extended and held in place by the electromagnet using a central linkage (second embodiment). The trigger works by cutting off the current flowing through the electromagnet, instantly releasing the spring. The resulting spring movement forces the mechanism to press a pair of brake shoes together against the two sides of the metal brake disc. According to the invention, the brake disc and the cutting wheel or disc are separate and located in separate compartments.

[0055] Monitoring equipment: Visual or optical monitoring systems:

[0056] For operator safety, an optical monitoring device is mounted above the working volume 102 relative to the cutting wheel 107. A preferred version uses a shield supporting a reflector 101 that extends toward the operator to reflect the view of the cutting wheel 107 from above to an internal camera. When a gloved, and therefore colored, hand is detected within a predetermined danger volume near the blade or cutting wheel, a trigger event or signal (SIGNAL) is quickly generated by the image analysis device. This initiates a rapid "brake pause" process as described below.

[0057] Detecting the approach of a hand rather than detecting actual hand contact is an advantage as it reduces the risk of operator injury and allows additional braking time. Associated software sets the exact limits of the invisible danger volume around the blade in the direction towards the operator position and to each side.

[0058] WO2023014232 (PCT / NZ2022 / 050094), a pending document, describes the creation of four spaced-apart viewpoints of the working volume 102, which are focused onto the image sensor of a machine vision color camera as four adjacent but separate images via a series of mirrors and focusing lenses. Image analysis equipment is adapted to identify, with reference to any one of the images on the image sensor, when a pixel representing the operator's gloved hand is within the danger volume surrounding the imaged cutting disk. Identification requires appropriate program constants, such as for tonal differentiation, to distinguish "glove pixels" in the image from "background pixels" generated by the workpiece or machine by color or brightness. Operators in the food industry are required to wear gloves, typically blue or green. These colors contrast with meat. Red gloves can be used for wood saws, and yellow for handling fish. Alternatives include fluorescent gloves and gloves with infrared contrast (possibly derived from fluorescence) that can be seen by the selected camera. The disk cutting machine includes adequate lighting for the work area, which may include lighting suitable for stimulating fluorescent gloves.

[0059] For the cutting wheel, the extent of the danger zone is best interpreted as "less than 20 mm from the cutting wheel." For example, this distance may differ between the left and right sides of the cutter. This depends on the speed of inadvertent hand movement and the overall machine reaction time. For example, the designer can assess how far the hand can travel during a total machine reaction time of 10 ms, which is typical for this invention, and set the danger volume to twice that distance as a safety margin. The contour of the danger volume will be a rectangular parallelepiped that includes the opposite vertical edges of the cutting wheel.

[0060] time limit:

[0061] This also applies to the second embodiment. The image analysis process may take 2-4 milliseconds, for example depending on the camera frame refresh; then, the release of the spring 304 may begin 2ms later and the rotating disc cutter may be stopped in 5ms. The immediate braking pause may take a total of 9 to 11 milliseconds. The inventor's safety protection history on band saws shows that slipping thumb, operator distraction and fatigue may be the cause of full braking. The movement of the hand can be up to about 2m.s -1 Or 2mm / millisecond. For a danger volume boundary set at 20mm from the cutting edge, a response time of 10ms should be sufficient. When using the visual form of the present invention, the gloved hand should never come into contact with the moving cutting edge.

[0062] Electrical Glove Contact Option

[0063] Alternatively, a conductive glove can be worn and connected to a current source connected to the machine chassis 100 via a current-carrying wire or equivalent. The onset of electrical conduction between the glove and the cutting disc can be indicated by a sudden change in the voltage supplied by the machine. A sufficient change, preferably distinct from that caused by contact between the glove and the grounded workpiece, will cause the brake to pause. It has been noted that operators using conductive gloves on disc cutters are reluctant to switch to ordinary blue latex gloves. A machine vision system and a conductive glove system can be used simultaneously. Optical or conductive sensing will cause the brake to pause.

[0064] A person skilled in the art may choose to rely solely on the electrical glove contact. This invention describes a brake-stop mechanism that has a faster stopping time than known prior art methods, at least for non-destructive methods. The total time does not include the 2-4 milliseconds for image analysis, so it may take 7 milliseconds, which is part of a revolution.

[0065] Motor and belt:

[0066] In one option, a cutter shaft 201, supported on bearings, carries a driven pulley, brake disc, and cantilevered cutting disc near one end. The other shaft, which carries a drive pulley for the drive belt, is rotated by a motor rated at approximately 750 to 1500 watts, such as a conventional AC shaded-pole induction motor (not shown). When supplied with 50 Hz AC power, speeds can approach 1500 rpm. Whenever possible, the motor's rotational inertia should be minimized. A smaller, lower-power induction motor can be selected. Induction motor versions with an iron cylinder rather than a solid iron armature have lower rotational inertia. Any embodiment can use a motor with lower rotational inertia, such as a brushless DC motor with a permanent magnet armature; for example, a 600-watt brushless motor (D110BLD600-48) or a 600-1000-watt air turbine motor (Air Turbine Tools, Boca Raton, FL). These have not been tested.

[0067] In the first embodiment, both shafts carry toothed pulleys that engage with timing belts. A preferred belt is a toothed reinforced rubber timing belt, consisting of fiberglass tensile cord and a neoprene body. It is a common type: HTD-8M and is 50 mm wide. When the machine is braked to a stop, all rotating components, including the motor via the belt, stop simultaneously.

[0068] As part of the braking pause, motor power is cut off. The inventors have noted that self-braking motors, including internal brakes that activate when power is removed, are too slow if used alone. Furthermore, because such brakes can disconnect blades on different shafts due to belt failure, if the belt fails during self-braking, the cutter shaft and cutting disc will not stop.

[0069] Cutter shaft:

[0070] The cutter shaft is a strong shaft because of the high forces generated during braking. Figure 2 1 is a front elevational view showing shaft 201 and its cantilevered extension 201a supporting cutting disc 107. A first bearing 202 and a second bearing 203 support the cutter shaft against the chassis of a machine (not shown). A brake disc 205 is aligned with closable brake pads 206, 209, and a driven toothed pulley 204 is aligned with a toothed drive pulley 418 on the first shaft to receive the drive belt. Both shafts typically rotate at approximately 1500 rpm. When spinning at typical speeds, the cutter shaft carries considerable forces, experiencing a braking pause. Force is also transferred from the brake disc 205 to the cutter shaft. Significant energy (often exceeding 100 kW) is extracted from the cutter shaft and converted into heat.

[0071] Figure 2 An elongated machine screw, with its head 207 located at the left-hand end of shaft 201, is shown as a means of assembling cutter shaft 201 in the first embodiment machine. To occasionally disassemble the shaft to replace a belt or brake disc, the machine screw can be removed. The left portion of shaft 201, up to brake disc 205, can then be detached from the largely concealed right portion 201A for maintenance.

[0072] A second support bearing (203) is provided. Preferably, one bearing prevents axial movement of the shaft, while the other bearing (such as a roller bearing) allows axial shaft movement. Bearing 203 is Figure 2 The brake pads 206 and 209 are partially obscured by a shield 108 placed on the operating side of the plate 208, which also separates the compartments (see above). The triangular pieces 206, 209 are brake shoes or brake pads. 412 indicates a steering knuckle comprising part of the brake pad linkage.

[0073] A guard 108 is supported from the face plate 208 and covers a cantilevered extension of the cutter shaft, extending into the operating area towards the cutting wheel 107. It supports a protective shield 109 around the blade.

[0074] Brake pads:

[0075] Preferred pad materials are selected from a range including cast iron, stainless steel, copper, phosphor bronze or other forms of bronze; also tested are automotive-type pads comprising fiber materials embedded in phenolic or acrylic resins. However, brake discs and pads are where a large amount of kinetic energy is converted into heat within milliseconds.

[0076] Physical installation of springs and brake pads:

[0077] The compressible spring 304 will store a force for closing the brake pads around the brake disc 205 during braking pauses.

[0078] The brake pads face each other. Pad 209 can be rotated about the steering knuckle so that during braking pauses the pressure of the quick release spring 304 applied by the linkage forces the pad and pad 206 together. It is found convenient to fix the brake pad 206 in place.

[0079] Figure 3 is a simplified illustrative diagram showing the principle of a preferred fail-safe brake mechanism, similar to the magnetic lock on a safety door. It is called "fail-safe" because the flowing current is maintained while the cutting disc rotates. As shown, the state is "cutting mode; brake released; electromagnet current flowing." The spring release has been fired, and contact between the brake disc 205 and the brake pads 206, 209 is prevented by the holding action of the magnetic field, which is generated by the current continuously applied in the windings 305 and 306 and circulates within the magnetically permeable soft electromagnetic core 301 (shown in hatching) and includes a movable armature 303. The armature is held against the soft ferromagnetic U-shaped (or possibly pot-shaped) core by the attraction of the magnetic field.

[0080] When the current in windings 305 and 306 is interrupted, the energy stored in compressed spring 304 allows armature 303 to be forced leftward, rotating brake pad 209 and thereby applying a high but controlled braking force to cutter shaft 201. The spring sets the braking force. The spring surrounds shaft 307, which is fixed to the armature and supported away from the windings. The shaft is pivotally connected to movable brake pad 209 to absorb wear. Fixed brake pad 206 is also pivotally mounted from the machine frame.

[0081] Figure 3 A reset cam 308 is also included. Rotated by a geared reset motor (not shown), the cam rotates 180 degrees and presses against a pivotally mounted lever 309 with significant force, pulling shaft 307 into the electromagnet and compressing the spring. At this point, current is turned on through the electromagnet, maintaining the spring in a compressed state. Before the brake is applied again, the cam rotates a second 180 degrees out of the way of lever 309. The electromagnet housing includes fins for heat dissipation.

[0082] Power outage

[0083] For either embodiment, the "fail-safe" design provides that if the actively maintained electromagnet current is interrupted for any reason (such as a general power outage, machine power failure, etc.), the armature 303 is released and a braking pause ensues (which does not require power). If a braking pause is not required, simply removing power to the motor in response to pressing the operator's "OFF" button will gradually decelerate the rotating cutting wheel.

[0084] Brake disc and its mounting parts:

[0085] Figure 6 Figure 2 is a front view of the brake disc 205. It is constructed of a metal such as steel or stainless steel. In this embodiment, the disc is approximately 5 mm thick and has a diameter of 100-120 mm. When braking occurs, splines 602 around the central aperture of the brake disc couple the braking torque to the sides of corresponding splines formed on the cutter shaft. The brake disc may include a series of perforations, such as 603, to facilitate air circulation, aid heat dissipation, and reduce rotational inertia.

[0086] Figure 7 704 is a cross-section showing a portion of a self-centering resilient mounting which allows some side-to-side movement of the brake disc 205 while maintaining a positive locking engagement between the splines during braking pauses. It has been found that it is more convenient to move only one brake pad (see below) and therefore the brake disc tends to twist during use due to the unequal movement of the brake pads. Two O-ring mountings 702, 705 each include a concentric groove for an O-ring 703, 704. Each "O" ring is compressed against the brake disc adjacent complementary splines, providing resilience against any twisting action. The adjustable ring can be held in place by a lock nut 701. The splines on the brake disc serve to prevent relative rotation on the cutter shaft.

[0087] The chassis of the machine 100 provides strong support for the bearings that hold the brake pads 209, support the steering knuckle 412, and the bearings for the cutter shaft 201 that supports the brake disc 205 and cutting disc 107. The chassis can be formed from 10 mm thick steel plate, using bending and welding to add strength.

[0088] Second embodiment

[0089] Figure 4 This is a front view of the rear side of a sturdy frame 400, which includes a stronger coil spring 304 rated at 650 lb per compressed inch (11,600 kg per meter). The frame is bolted to the machine frame as two connecting components 402 and 403 using bolts 401A, 401B, 401C, and 401D. Straps 418 reinforce the frame. Frame 400 is mounted vertically inside the disc cutter. It supports the force applied by the brake arm, closing the brake pads around the brake disc.

[0090] Spring and trigger:

[0091] The spring 304 surrounds the telescopic guide shaft 410 and is constrained between end stops. One stop is a pneumatic tensioning or firing cylinder 408. A spring force of typically about 2000 N has been used, where the force delivered to the brake pad is multiplied by the mechanical leverage ratio provided by the brake arm and Figure 2 、 Figure 4 and Figure 5 The axis size of the steering knuckle 412 is centered around the cylinder. The cylinder is anchored to the frame 402 at a pivotable mount 405. Another stop is located at a variable collar 415, which is adjustable to allow variation in spring length and delivered force. The movable end is retained by a clevis that pivots at 406 to a brake arm or beam 411, which is rotatably supported by an attached steering knuckle (end: 412). The cylinder 408, telescoping guide shaft 410 within the coil spring 304, the spring, and the clevis 407 pivot from the brake arm as a unit during firing and release, with a protrusion or tongue 417 at one side of the clevis being restrained against the spring force by an extending finger 413, which is held in place by an over-center mechanism maintained in place by current in an electromagnet 419.

[0092] A relatively low power electromagnet 419 is used because, unlike the first embodiment, the full force of the spring is not directly retained. An over-center release mechanism within the housing 414 holds the finger in place against the spring with a relatively low electromagnet current.

[0093] release:

[0094] When the current in 419 stops, the fingers withdraw and the now released spring 304 forces extension, causing the pivot 406 and brake arm or beam 411 to rotate in a clockwise direction ( Figure 4 view) moves and rotates the firmly connected brake pad 206 (see Figure 5 The partially obscured brake disc 205, held on the partially obscured cutter shaft 201, is clamped between two pads. The force of the spring is usefully amplified at the knuckle 412 by the ratio of the length of the brake arm 411 from the pivot to the knuckle 412 divided by the length of the movable brake pad 206 from the knuckle axis. The friction area of ​​each brake pad is approximately 800 mm. 2 .

[0095] The advantage of the present invention is that the brake is applied with a predetermined force, which is set by the characteristics of the compression spring 304, the amount of spring restraint, and the ratio described above. By varying the spring pressure using the collar 415 or by using a weaker spring, the braking duration can be controlled from approximately 2-4 ms upwards. Braking is not a catastrophic event. The extended time is available due to the use of optical proximity sensing rather than contact sensing as described above under "Time Limit."

[0096] Figure 5 is a schematic, angled front view of the portion comprising frame 501, movable brake pads 206, and stationary pads 209; on either side of the space 205A occupied by brake disc 205 (not shown). 502 is the covering over the bearings that surround and support the steering knuckle. Casting 503 is the end support for these bearings. The steering knuckle transmits the rotation of brake arm 411 to pads 206. Having a relatively long yet strong knuckle is an advantage, as the knuckle and its bearings are subject to high forces during use.

[0097] In this embodiment, no lateral resilience is provided between the brake disc 205 and the cutter shaft 201. The disc is bolted to a collar surrounding the shaft. The disc may flex during braking pauses.

[0098] A solid-state switch, such as a suitably rated and transient-protected power MOSFET, can be connected to short-circuit the electromagnet's coil when the electromagnet's control electrode is driven ON. This accelerates the collapse of the electromagnet's magnetic field, rapidly dissipating the inductive power within the winding's resistance and rapidly retracting the fingers 413.

[0099] Internal inspection:

[0100] The machine includes transducers for monitoring and safety purposes; for example, to report the rotation of the drive shaft, to report the rotation and stop rate of the cutter shaft, to report the linear movement of the spring 304 (or a strain gauge may be used to report the compression of the spring), and to report the movement of the movable brake pad 209. If a brake pause is performed for too long, it will be unsafe. In this case, the machine will be disabled until the cause is found and corrected by maintenance personnel. A regular maintenance call can be made after a predetermined number of emergency pauses.

[0101] It has been found useful to control each disc cutter with an internal industrial PC having sufficient power to manage functions including test runs, operator control and monitoring, and basic image processing. The PC drives the operator display 104. It should frequently perform self-test procedures to prevent components from malfunctioning, which could result in a hazardous condition.

[0102] Data and reports:

[0103] This "second actuator" or management safety function is a useful attribute of the disc cutter. Figure 8As shown in , the internal PC of the disc cutter 100 records and can immediately report each occurrence of the brake pause function to a local server 800 having a supervisor display 802 via a local area network 801. The report can be further sent to another server 804 using another network 803. Each disc cutter may have its own URL or Internet address. Typically, each report identifies the operator and machine, location, time and date, environmental conditions, a report on motor load, and may include a short video of images collected before each brake pause. For example, a supervisor with a display dashboard 802 will be informed if an operator makes an unusually large number of brake pauses during a work shift. The supervisor can take remedial measures. A replay of the video may be evidence to prevent harm. To this end, the industrial PC is programmed to save the most recent set of images analyzed as a video clip for use in the report.

[0104] Example PC processing steps:

[0105] 1. The operating area is illuminated. (Assuming the operator has entered a name).

[0106] 2. Review the "Last Braking Pause Time". If the machine does not brake quickly enough, prevent it from being used until it is serviced.

[0107] 3. The machine vision device is self-checking, or perhaps by an operator extending a gloved hand toward the edge of a stationary cutting wheel. Proximity detection in this case can include an audible or visual signal, or both. If valid, work can begin.

[0108] 4. The spring is compressed and will be held during use of the machine by maintaining the electromagnet current and holding the finger 417 in the extended position.

[0109] 6. The cutting wheel motor can run and the cutter can be used.

[0110] 7. The process is stopped by braking, withdrawing the finger 417 or normal stopping.

[0111] Sequence of steps for brake hold:

[0112] 1. Detection of a hazardous situation, such as any part of a gloved hand being imaged by the machine vision device within a threshold area around the cutting disk, results in the generation of an internal signal (SIGNAL), which is the decision to execute a braking pause. (Electrical conduction can also be sensed.)

[0113] 2. The holding current in the electromagnet 419 is interrupted; the spring 304 is released and the movement of the beam 411 along an arc centered on the knuckle 412 causes the movable brake pad 209 to press the brake disc against the fixed brake pad, quickly bringing the cutter shaft to a halt.

[0114] 3. The motor drive power is also cut off. The time to stop is compared with a predetermined value to ensure that the machine stops quickly.

[0115] 4. The device is ready to go through the start steps again.

[0116] Other embodiments.

[0117] For even faster stopping times, use a higher spring force applied to the brake pad or a different pad, always taking into account the machine frame stress. For slower stopping times, reduce this force. For example, the spring strength or amount of preload can be varied, as can the brake pad material or the force multiplier provided by the specific geometry of the lever arm and pivot center.

[0118] When no other shaft is used, the motor can be connected to the cutter shaft carrying the cutting wheel directly or through a resilient in-line coupling. Suitable motors include brushless DC motors with relatively low rotational inertia. Air turbine motors can be used. It has been found that at least some cutting wheels can tolerate rapid braking pauses.

[0119] advantage

[0120] The present invention provides a reasonably fast response if the operator's gloved hand is detected within a range defined by proximity to the cutter blade. Detection can cause the cutter wheel to stop rotating before the hand can reach the blade.

[0121] Optionally, intrusion is detected by electrical contact with a conductive glove.

[0122] In the event of a power outage, the disc brakes are activated.

[0123] If the cutter shaft belt breaks during the braking pause, the machine will stay in a fail-safe condition.

[0124] If the transducer detects incomplete spring compression, the machine enters a "safe state" and the motor cannot run. Alternatively, if the previous braking stop took too long, the motor will not run until repairs are made.

[0125] No sacrificial components are consumed during a brake stop and the machine returns to the "ready" state within seconds.

[0126] The actual braking time may increase from the nominal 2-4ms and may be longer than that of a conductive type machine because the "hand approaches the blade" occurs faster than the "hand actually contacts the blade".

[0127] Particulate matter from the brake equipment cannot enter the work area because the brake mechanism is located in a separate compartment. Likewise, the brake mechanism cannot be contaminated by the material being cut or by periodic flushing, and the brake compartment can be heated to avoid condensation.

[0128] Finally, it should be understood that the scope of the present invention as described and / or illustrated herein is not limited to the specified embodiments. Those skilled in the art will appreciate that various modifications, additions, known equivalents and substitutions are possible without departing from the scope and spirit of the invention as set forth in the appended claims.

Claims

1. A hazard response device included in a disc cutter having a motor and a rotatable cutter shaft, the cutter shaft being supported by a frame by means of bearings, the bearings supporting the cutter shaft and cutting disc in a working area, characterized in that The cutter shaft also fixedly supports a discrete brake disc having sides and disposed in a space between a set of facing brake pads mounted on the frame; The hazard response apparatus is adapted to, when in use, cause the first actuator to respond to a detected hazard by causing energy stored in a spring to be released, whereupon movement of the spring causes a linkage of at least one movable brake pad to press the brake pad against the side of the brake disc, thereby generating friction during a braking action and rapidly stopping the cutter shaft and the cutting disc within a controlled period of time.

2. The danger response device according to claim 1, characterized in that: The brake disc is supported by the cutter shaft in a compartment separate from the working area.

3. The danger response device according to claim 1, characterized in that: The first actuator is selected from a range including a reversibly closed magnetic circuit and an electromagnetic trip device acting on an over-center latch, the first actuator causing a rapid release of energy to the linkage when activated.

4. The danger response device according to claim 3, characterized in that: The linkage includes a brake arm pivotally connected to the spring and fixedly coupled to a rotatable knuckle supported by the frame; the rotatable knuckle is in turn fixedly coupled to the movable brake pad.

5. The danger response device according to claim 1, characterized in that: A prime mover selected from the range comprising an electric motor, a hydraulic piston and a pneumatic piston is provided in a configuration suitable for recovering the energy stored in the spring, thereby returning the cutter to a safe and stoppable condition before the cutter is used.

6. The hazard response device according to claim 1, characterized in that: The cutter shaft is driven directly by the motor.

7. The hazard response device according to claim 1, characterized in that: The cutter shaft is indirectly driven by a flexible drive selected from the range consisting of a belt drive and a synchronous belt drive, operatively coupling the cutter shaft to another shaft driven by the motor.

8. The hazard response device according to claim 1, characterized in that: The monitoring device capable of detecting an unsafe situation in use includes a camera and a lens, which, when in use, is capable of forming at least one image of a danger volume including a preset area around the cutting disk, and detecting an image of an object with a preset distinctive appearance within the danger volume, and if detected, causing the first actuator to perform an action.

9. The hazard response device according to claim 8, characterized in that: The detected image is distinguished from the background by an image analysis device receiving the image from the camera, and the distinctive appearance is selected from a range of color characteristics including blue gloves, green gloves, yellow gloves, red gloves, fluorescent gloves or infrared fluorescent gloves to be worn by the operator.

10. The hazard response device according to claim 1, characterized in that: The monitoring device includes a device capable of detecting electrical contact between a conductive glove worn by an operator and wired to a sensing member within the hazard response device and a portion of the disc cutter including the cutting disc; the electrical contact causes the first actuator to perform an action.

11. The danger response device according to claim 8 or claim 10, characterized in that: The hazard response device comprises an evaluation member for evaluating the time elapsed after detection until the cutting wheel stops, and preventing the disc cutter from being used if the evaluated time exceeds a predetermined limit.

12. The danger response device according to claim 8 or 10, characterized in that: The monitoring device capable of detecting unsafe conditions during use also includes a second actuator; the second actuator includes a digital accident reporting system, which is configured to prepare an accident report and transmit the accident report to a server via a network when the monitoring device is caused to respond to a hazard.

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