Integrated Motion Systems - Motion Control Tips

AquaGard 7350 V2 Sanitary Conveyor Platform is redesigned

May 17, 2019 By Paul Heney Leave a Comment

The high sanitary and safety attributes of Dorner’s newly redesigned AquaGard 7350 V2 Series has earned it the coveted Baking Industry Sanitation Standards Committee (BISSC) certification for conveyors outlined in ANSI/ASB/Z50.2-2015. BISSC certification is recognized as the definitive sanitation standard for equipment used in the baking industry.

Launched in October 2018, the redesigned AquaGard 7350 V2 Series merges the best qualities in accessibility and safety to deliver a sanitary platform that’s perfectly engineered for the baking, snack food, pharmaceutical, pet food and packaging industries that require wipe-down and occasional wash-down cleanings of the conveyor. The new conveyor comes in belt, modular belt and positive drive options, and can be configured in straights, curves and Z-frames.

Specific design features that helped the AquaGard 7350 V2 earn BISSC certification include:

• Bolt-together 304 stainless steel frames
• FDA-approved belting and plastic components
• Open design with minimal horizontal surfaces
• Ample access for cleaning and maintenance
• Suitable for both wipe-down and low-pressure washdown cleanings with non-caustic solutions

Additional sanitary and safety features on the modular belt curve conveyor include having no openings greater than the international standard of 4mm — which increases safety by eliminating pinch points for operators. Furthermore, the upper and lower chain edges are fully contained in the drive system to reduce catenary belt sag and conveyor noise.

Dorner
www.dornerconveyors.com

Drives and controls for robotics: See them at the 2019 Robotics Summit

May 16, 2019 By Lisa Eitel Leave a Comment

In a couple weeks, the 2019 Robotics Summit (focused on the design, development, manufacture, and delivery of commercial robotics) will take place in Boston. It will be co-located with the DeviceTalks event at the Seaport World Trade Center. One display will be an array of precision processing and powering technologies for robotics.

Elmo Motion Control • Booth #118 — This is a top visit if you’re interested in drives and controls for on-robot (distributed) control. We recently touched on some multi-axis solutions for these setups in a visit at Automate:

In fact, you will get to see Brian Mason (who gives the booth tour in the above video) on Wednesday, June 5th at 2:00 at the Robotics Summit, when he will present on motion control in robots. You’ll also get to ask him questions about miniature network-based servo drives and novel ways to power and control robot joints for less cabling.

Infranor • Booth #139 — Look for servo drives and servomotors here, and give us a shoutout on LinkedIn if you end up having a conversation with this company about new robotics applications for semiconductor, packaging, or aerospace industries (and are at liberty to divulge a vague detail or two).

Performance Motion Devices • Booth #145 — Little-known fact about PMD … this company is well-versed in sharing motion fundamentals with the industry. So if your primary engineering focus is in fact not motion control and you attend the Summit, say hello to the team here to get answers to questions you’ve always wanted to ask but felt were elementary. Performance Motion Devices sells multi-axis motion products (and ICs, digital drives, and amplifiers, and machine boards) and provides technical support on these technologies.

PI • Booth #151 — Physik Instrumente makes regular appearances in our editorial for its precision subsystems. Piezomotors feature large in a lot of miniature designs — see what we did there? — although this company integrates a whole host of other actuator and motor types as well as various kinematics iterations. Check out this FAQ for more on the kinematic possibilities for some robotics: What’s the difference between serial kinematics and parallel kinematics in multi-axis motion design?

This is a piezo motor from Physik Instrumente (PI) that moves to 200 mm/sec. It has an integrated driver.

Kollmorgen • Booth #202 — Catch up on the features and case studies we’ve done (listed below) on how to size and apply servomotors, frameless motors, and stepper motors to robotics and other applications. Then go see the engineers from Kollmorgen at the Summit to see what new robotics applications they observe on the horizon for these technologies — especially for collaborative robots, industrial articulated robots, and medical robots … and particularly those employing frameless motors (a huge trend in the industry) as well as harmonic gearing for high torque density and smaller and faster robots.

Trends in electric motors Part II — Scott Evans sets record straight on motion design

Difference between continuous ratings and holding continuous loads (an ac servo-motor terminology primer)

Thermal time constants and managing PMAC servo motor overloads

Frameless motors and gearmotors for robot design at XPONENTIAL 2019

JF Shaw • Booth #212 — You’d be hard pressed to think of a component used in automaton and robotics that this company doesn’t supply, as they include sensors, connectivity equipment, motors, and drives; mechanical offerings relevant to the application of robots include spur gears, industrial belts, pulleys, and couplings … as well as whole assemblies and end-of-arm tooling including electrical and pneumatic grippers. We editors at motioncontroltips.com are just learning of the capabilities from this supplier ourselves, so stay tuned in coming months to get more on its engineers’ expertise in the design and integration of various industrial applications.

Forest City Gear launches advanced facility for gear-blank production

April 29, 2019 By Lisa Eitel Leave a Comment

Forest City Gear has expanded its turning and milling operations with a state-of-the-art facility designed to greatly improve lead times and quality for the production of precision gear blanks.

This highly productive 8,500 sq. ft. facility is in close proximity to Forest City Gear’s main facility in Roscoe, IL, and now dedicated almost solely to the precision turning and milling operations needed to produce precision gear blanks. That’s very good news for Forest City Gear customers, says Forest City Gear Turning and Milling Supervisor Mike Miller.

“This gives us complete control over the quality and delivery of the blanks (and slugs) that are the ‘near net shape’ starting point for many of the gears we produce,” Miller says. “The types of projects we take on here at Forest City Gear for customers around the world have never been more demanding from a quality and delivery standpoint.”

He continues: “If we start off a project with turned blanks out of tolerance, or waiting for blanks from a supplier, this can ultimately create a devastating production bottleneck when operations upstream are sitting idle waiting for product to arrive.”

According to Miller, the facility (with its four late-model CNC lathes, three CNC machining centers, and dedicated Zeiss CMM) easily meets current capacity requirements, and gives the company much additional room to grow. Two Mazak Quick Turn 250 Turning Centers will arrive later this year to expand capacity, and future plans call for the addition of a 5-axis machining capability for the production of small planetary housings and carriers.

Since 1955, Roscoe, Ill. based, family-owned Forest City Gear has been one of the gear industry’s leading sources for the development, manufacture and inspection of the highest quality gears, for use in applications that range from medical devices to motorcycles, airplanes to automation, even including the Mars Curiosity Rover.

For more information, visit www.forestcitygear.com.

Conveyor and material-handling trends (a Motion Trends report)

April 5, 2019 By Lisa Eitel Leave a Comment

Conveyors are at the heart of an array of exciting changes in material handling — from the vast installations of automated warehousing to humbler stations only recently automated. Each conveyor installation has unique design requirements: Food and beverage conveyors might need to survive washdown settings; conveyors in airspace and defense operations may need to be explosion-proof; and conveyors automotive manufacturing facilities may necessitate conveyors with very high load ratings. Recently, two industry experts gave us their input on what’s new in these and other designs … and trending features of the conveyors themselves.

This Flex E Pack system from Wexxar Bel (in partnership with Matrix Packaging Machinery) is a conveyor-based end-of-line packing station to help automate processes associated with forming packing, and sealing containers. It’s one example of the growing trend to reduce labor and increase throughout of flexible packages.

One enduring trend includes the move towards flexible conveyor systems — fully assembled and tested solutions that go beyond the functions of traditional belt conveyors.

Tom Schaffner | Sales and business development manager • mk North America: Customers are looking for flexible automation today; but this was not the case five years ago. Nowadays (with product lifecycles being as short as they are) flexible automation is a necessity. These trends are seen more often in applications that require a conveyor-solution … beyond standard belt conveyors.

Shown here is a timing belt conveyor from mk North America with welded attachments for indexing and positioning.

Stacy Johnson • Dorner: It’s important to recognize how conveyor design is being affected by the continuing trend of flexible assembly lines. When customer demands change and product cycles end, assembly lines must be flexible to accommodate different applications. Supporting conveyor systems need to be just as flexible.

In some cases, high-tech distributors and integrators execute some or most of the work related to customization and installation. These teams sometimes assume the execution of control-design work for setups having coordinated motion tasks as well. This is increasingly common where SCARAs and other robotic arms service a conveyor.

Stacy Johnson • Dorner: The role of conveyors within automation and robotic systems continues to expand. Robotic movements are precise and exact, and conveyors working with robotics need to operate to that same level of accuracy.

Robotic applications often require product to be in an exact location, in the exact position, and at the exact time on the conveyor. But to do that successfully requires a conveyor system that’s efficient, reliable, and engineered to work in conjunction with robotics. Not every conveyor can do that. But our servomotor-driven Precision Move conveyors can … delivering accurate alignment of time and distance that provides indexing repeatability of ±0.040 in. all at a rate of 100 indexes per minute. It’s important to select a conveyor supplier with knowledge, application insight, and the proven expertise in working with robotics.

Note the distinction between pallet (pallet-system) conveyors and large conveyors for the transport of pallets (moveable adaptations of skid platforms) bearing product. The former is associated with precision placement of discrete workpieces or products … and even on-conveyor processes in some cases. The latter — as in this example from RIA-certified robot integrator Honeywell Intelligrated — are associated with heavy-load material handling for the transport of crates or other collections of discrete product — usually in warehousing or distribution settings.

Pallet conveyors — not to be confused with heavy-duty pallet-handling conveyors in this context — are those that include trains of discrete carrier trays or platforms (pallets) to transport individual products or workpieces. Key benefits of pallet conveyors include the ability to space (buffer), route, and position products as operations around and sometimes on the conveyor demand it.

In some cases, the pallets include RFID tags to allow automation controls and IoT logistics systems to track their locations and the current state of the product or workpieces they’re carrying.

In addition, these pallet conveyors are usually reconfigurable to let plant managers use them for changing production lines.

This is a 2200 Series Precision Move pallet system from Dorner Mfg.

Stacy Johnson • Dorner: Pallet system conveyors have become a popular choice for many automation-focused applications that require exact movements and positioning of parts, as they can be setup or programmed to start and stop at specific intervals to sync up with robotic interaction or other processes. These types of conveyors dominate in automotive component manufacturing as well as other industries — including the production of medical devices, electrical components, and electronics as well as product testing and inspection that necessitate automated and manual assembly or handling of products.

Pallet system conveyors are available in multiple styles … including dual-belt configurations powered by common drives and flexible plastic-chain belt designs. Our innovative lifting modules can be used to interface with robots, rotate product 90° or 180° or change product orientation. Plant end users also employ pallet system conveyors for their accuracy. These operations need their product at an exact location … and the conveyors’ lift-and-location stations deliver repeatability of 0.002 in. Pallet systems are available in a variety of layouts to accommodate tight turns, heavy-load applications; and vertical transfer units.

Schaffner • mk North America: Conveyors and their accessories — in particular pallets that carry product — must be flexible. The VersaMove pallet-handling conveyor line from mk North America is suitable for applications where change is expected. Pallets can easily reconfigure with new tooling to accept different parts. Stops, accessories, and even whole conveyors can be added to the line as the functionality of the line changes. In today’s conveyor marketplace, it’s a requirement to offer flexible conveyors that can easily be reconfigured on a moment’s notice.

Stacy Johnson • Dorner: Modular conveyors are mobile and provide the flexibility to be moved to different production lines. When this occurs, the conveyor’s guiding, transfers, and other accessories may need adjustment. Well-designed platforms allow this to happen.

One such platform that brings flexibility to the forefront is retractable tail conveyors. This platform allows one end of the conveyor to shorten or lengthen, depending on where the plant operator wants the product. Some common uses for retracting tail conveyors include evenly distributing product across another conveyor; changing product orientation; and rejecting product for weight, foreign material, or other quality issues.

Low-profile XY stage features 1-micron resolution, 2-micron repeatability

March 26, 2019 By Miles Budimir Leave a Comment

The AU200-100×100-SC (Solid Core) stage is the newest addition to the expanding line of precision XY stages from OES (Optimal-Engineering Systems, Inc.) The linear travel of the X and Y axes is 100 mm x 100 mm (3.937 in. x 3.937 in.) and the resolution of the X and Y axes is 20 microns (non-micro-step) or 1 micron (20 micro-steps per step motor driver in use), the typical repeatability is 2 microns, and the typical positional accuracy is 3 microns. A low-profile XY stage measuring just 80 mm (3.150 in.) high with a compact footprint (including the motors) of 348 mm x 348 mm (13.701 in. x 13.701 in.), the stage is designed for alignment, assembly, laser drilling and machining, industrial, medical, testing, scanning, semiconductor handling, and optical applications.

Preloaded V-groove and crossed roller bearings and ground 4 mm per-turn lead screws having just 2 microns of backlash all contribute to the high precision and stiffness of the AU200-100×100-SC stage. The table measures 300 mm x 300 mm (11.811 in. x 11.811 in.) and has a precision pattern of 21 drilled and threaded mounting holes to easily add special tooling or fixtures, and for easy integration into new and existing applications. Additional tooling plates are also available for custom and interchangeable applications.

The standard two-phase (1.8˚) stepper motors have knobs for manual adjustments of each axis of the stage. However, the knobs can be replaced with incremental encoders for position verification. As an option, servo motors and compatible motion controllers are also available from OES, or the AU200-100×100-SC stage can be ordered as a complete plug-and-play motion control system.

For more information, visit http://www.oesincorp.com.

Dorner Latin America Now Manufacturing at New Facility in Mexico

March 11, 2019 By Danielle Collins Leave a Comment

Dorner’s new manufacturing facility in Guadalajara, Mexico (Dorner Latin America) enables the company to build and deliver belt and flexible chain conveyor systems more quickly and efficiently for customers throughout Latin America.

Dorner is an industry leader in the design, application, manufacturing and integration of precision industrial and sanitary conveyor systems.

The new facility, staffed with experienced employees, is manufacturing Dorner’s popular 2200 Series low profile belt conveyor, which is ideal for assembly, light manufacturing, and other industrial applications. Additionally, the facility is also manufacturing FlexMove flexible chain conveyors, which are designed for pharmaceutical, paper converting, and consumer goods packaging applications. All Dorner conveyors and equipment will be supported through the Guadalajara customer service and engineering teams.

“We have seen tremendous growth in Mexico and Latin America. We’re excited to open a new manufacturing facility and continue expanding our team in Guadalajara so we can provide better and faster support for our customers,” said Dan Nasato, Vice President – International, Dorner.

Dorner – Latin America is located at:

Dorner Latin America, S. de R.L. de C.V.

Carretera a Nogales #5297, Nave 11

Fracc. Parque Industrial Nogales

Zapopan, Jalisco C.P. 45222 México

To contact Dorner – Latin America, call +52.33.30037400 or email: info.latinamerica@dorner.com.

What are pallet conveyors? (Not to be confused with pallet-moving conveyors)

March 8, 2019 By Danielle Collins Leave a Comment

Pallet conveyors transfer discreet products on carriers referred to as “pallets,” typically transported by belt, roller chain, flat-top chain, or for extremely high loads, powered rollers.

For the heaviest loads, in applications such as appliance assembly and automotive manufacturing, pallets are transported by rollers.
Image credit: Bosch Rexroth Corporation

Although they’re typically offered in standard sizes, pallets can be tooled with custom fixtures to locate and secure the product on the pallet.
Image credit: Glide-Line

Pallet sizes are, for the most part, standardized among manufacturers in metric dimensions (240 x 240 mm, for example), although some manufacturers offer pallets in inch or non-standard metric dimensions. In many cases, conveyor pallets are tooled with custom fixtures to locate and secure the product on the pallet. So not only can the pallet be accurately positioned on the conveyor, but the product can be precisely located on the pallet. This makes pallet-based conveyors the ideal solution for high-precision assembly, machining, inspection, and positioning tasks.

Note that the pallets discussed here are different from the pallets used for storing and handling bulk goods, which are often made of wood or plastic. Similarly, some roller- and chain-driven conveyors are marketed as “pallet conveyors,” for the transportation of these wooden or plastic pallets through a factory or warehouse.

Pallets can be transported around corners without changing the pallet orientation.
Image credit: Dorner Mfg. Corp.

Pallet conveyors are suitable for transporting products in two dimensions, but can accommodate small elevation changes. Curved sections — typically from 15 to 180 degrees — allow conveyors to change the direction of transport while maintaining pallet orientation. Conveyor modules referred to as “lift and rotate” units allow the orientation of the pallet to be changed while maintaining the direct of transport. Pallets can also be lifted and precisely located, for positioning at a workstation or inspection area, where pallet conveyors allow access to the workpiece from more than one side. For access to the bottom of the workpiece, pallets can be made with an open center.

The use of pallets to move individual products allows non-synchronous movement, so each product can be transported and routed independently. Because the pallets are precisely machined, they can be accurately positioned and located via sensors, and RFID tags or other data carriers can be attached to each pallet to track and document individual product movements. Pallets can be diverted and merged for offline operations, and accumulation allows products to be buffered, smoothing the flow of downstream operations.

Here, pneumatic cylinders are used to stop and lift the pallet. Precise locating is achieved by pins that mate to bushings on the pallet.
Image credit: mk North America, Inc.

Most pallet conveyors — especially those used in automation applications — are modular, based on standard conveyor sections, legs, and lift/transfer/rotate modules that can be easily reconfigured or expanded as needs change. And because components are standardized, pallet-based conveyors can be configured to meet a wide range of environmental requirements, including cleanroom, dry room, washdown, and ESD-compatible applications.

Feature image credit: Dorner Mfg. Corp.

mk North America introduces CAD360! conveyor modeling tool

February 27, 2019 By Lisa Eitel Leave a Comment

Leading conveyor system designer and manufacturer mk North America has announced the official release of a new online conveyor modeling tool — CAD360! — that makes it faster and easier than ever to design and share custom designed conveyor systems.

The latest release (which replaces QuickDesigner) adds industry-leading speed to the modeling process. Users can work via the web on one page without having to navigate to multiple pages or install software. With CAD360! users simply input the target values for length, width and height, select drive location and target options, and the model is generated on demand. Users can create a single-belt conveyor or choose from a variety of predesigned conveyor-system layouts.

“CAD360! is a very powerful and complete tool for modeling and designing in all facets of a project. Engineers can design anything from simple conveyors to complex multi-module pallet handling systems,” said Todd St. Pierre, Vice President of Operations at mk North America. “In fact, this program can be used by designers, engineers, and project managers. We are very excited to offer a complete solution to support customer requirements during the design phase of their project.”

CAD360! is a comprehensive offering for designing conveyor systems using an online CAD modeling tool. It allows for 2D and 3D models to be downloaded … and the use of PDF and JPG files for easy sharing across departments and non-technical teams.

“mk’s CAD360! tool helps our team simplify and streamline the quoting and design process,” added end-user Shadi Rizk, Engineering Manager at I-C Automation, on how the new tool is being used to transform operations. “We now easily generate a 3D model in the native CAD format to incorporate in the simulations and drawings, then turn around and give it back to mk for pricing; ensuring we are getting exactly what we need when we need it.”

For more information and to begin using CAD360! visit www.mkCAD360!.com.

Located in Bloomfield, Connecticut, mk North America Inc. is a leading designer and manufacturer of conveyor and material handling systems. The company’s original Aluminum Framing System continues to serve as the base technology in all of the new solutions mk brings to market — which today includes 20 different aluminum conveyors, the VersaMove pallet-handling system, CleanMove stainless steel conveyors, and aluminum framing.

Mach III Clutch Inc. supplies mechanical friction torque limiter for fish-barrier hoist

February 26, 2019 By Lisa Eitel Leave a Comment

Reclamation District 108 is a 150-year-old water district located in the Sacramento Valley that provides irrigation, drainage, and flood protection to farms and rural communities in the area. But drainage and flood-control canals in this region pose a risk to adult salmon who return from the sea through the San Francisco Bay to make their way up the Sacramento River to spawn. One wrong turn may find the salmon traveling up dead-end basin drains that put them at risk of becoming trapped and dying without fulfilling their life’s mission of reproduction.

Image courtesy of Murray McCaig of Municipal Treatment Equipment.

So to prevent this, Grimes, Calif.-based RD108 — in cooperation with the Department of Water Resources, State and Federal fishery agencies and local landowners — contracted help to reconstruct the Wallace Weir … a barrier at the Knights Landing Ridge Cut about 30 miles north-northwest of Sacramento. This cut is where (especially during flooding) most fish were entering the rural floodplain with no bypasses or return passages to the river.

Six grated barriers (each 16 ft x 29 ft) are shown here — and the rightmost screen in a lowered position. The grates are hinged to work as large flaps. Salmon that bump into the raised grates tend to turn around and seek another route. Image courtesy of Murray McCaig of Municipal Treatment Equipment.

Now the cut includes movable grated barriers (also called picket weirs) to let water flow but prevent salmon from swimming onward. The grates are automated to maintain the picket tips two feet above the water surface.

Six grated barriers hinged to underwater structures (at their bottom edges) connect to cables on their top corners to act as large automated flaps. When meeting a screen in the raised position, salmon bump into its diagonal underside. Their instinctual behavior here is to turn around and seek another route.

Shown here is a Wallace Weir hoist arrangement designed by Murray McCaig and two other engineers and first employed in 1983. Item 5 is a Rotork actuator; item 3 a parallel helical drive with worm gear; items 8 and 9 a drum; item 7 a cross shaft; an item 11 a coupler. (From the June 21, 2017 Barnard Hydro Solutions Inc. report: Municipal Treatment Equipment — Wallace Weir Fish Screen Hoist • Torque Limiting Device Design)

Each of the six grates is individually raised and lowered by its own dedicated hoist. The original version of the hoist was engineered by Murray McCaig (now of Municipal Treatment Equipment) and two other designers in 1983 for use on water-control gates. The original stayed stationary once set … so if an operator closed the gate, it remained closed until an operator reopened it.

But the fish-barrier application faced a complicating design problem. Debris buildup on the grates during flooding could induce sudden and unpredictable spikes in force at levels sufficient to pose structural risk to both the grates and their hoists. So the design’s engineers decided the grates had to automatically lower without intervention in such situations … to a level just sufficient to allow debris to be swept over the gate.

That’s when Murray McCaig contracted Barnard Hydro Solutions to devise a mechanism that would lower the grates automatically upon overload.

“We quickly realized that using load cells, controllers, and electric actuators to open the fish screens would be insufficient and too slow to effectively dissipate the sudden loads,” explained Jeff Barnard, P.Eng. for Barnard Hydro Solutions Inc. “That’s why we pursued use of a torque-limiting device into the existing design.”

Custom-designed torque limiter gives fish gate quick response

Years ago, Barnard worked for another company employing torque limiters from Mach III Clutch Inc. — torque-limiting couplings that plug directly into the #3 Morse taper inputs of heavy-duty power drills. The drills rotated 2-in. square operating nuts to raise and lower water control gates. Now this product is a Mach III catalog item.

Remembering the torque-limiting solution, Barnard connected with Mach III engineer Ron Ashbrook and worked with Ashbrook on a custom design to mount between the fish gate’s Rototork electric actuator (and SAF77 gearbox) and its parallel helical drive.

The torque limiters to open the fish screens — customized T8C2K-001 mechanical friction torque limiters from Mach III — support the dead weight of the actuator and right-angle gearbox — 255 lb. They withstand constant exposure to the outdoor environment. They also allow in-field adjustments and directly connect to the flanges of the design’s existing components. An enclosed housing has two access ports covered by removable sealed panels; the ports allow access to torque adjustment nuts. In fact, the ports’ width is customized to accommodate an open-end wrench for loosening an internal jam nut; then this nut can be rotated until the target torque is reached … and the jam nut retightened to hold the slip-torque setting.

An adapter plate facilitates connection to the parallel helical drive; the limiter’s housing is designed to support the overhung load of the Rototork actuator and its SEW SA77.

Mach III supplied a total of six T8C2K-001 units — one for each hoist. The torque limiters are B5 flange-mounted units of nonstandard frame size; have a 55-mm input bore and 55-mm output shaft, and total torque capacity to 17,000 lb-in., according to Mach III president Lesli Riehemann. They’re also factory burnished … with slip torque set to 12,967 lb-in. (to within ±10%).

How the final hoist design works

The new hoist systems at the Wallace Weir were placed into service in January 2018, and Reclamation District 108 continues to manage it. The torque limiters hold the 16 x 29-ft grates in the raised position until force against the screen exceeds 13,500 lb. The force then travels back through the helical drive and into the torque limiter, exceeding the set torque value of approximately 13,000 lb-in.

Shown here is a Mach III T8C2K-001 mechanical (friction) torque limiter installed on the fish-screen hoist system at the Wallace Weir fish rescue facility. It’s a B5 flange-mounted unit 55 mm in diameter with total torque capacity to 17,000 lb-in.

T8C2K-001 mechanical (friction) torque limiter CAD drawing courtesy Mach III.

Then the torque limiter’s internal friction and drive surfaces slip against one another to let force on the grate unwind the cables … and lower the grate in the process. Water (and debris) flows over the gate; position sensors detect the change in the grate’s position and send an alarm. An operator is dispatched to the site to reset the grate.

Shown here is the retrofitted hoist system at the Wallace Weir. Mach III was initially brought onto the project by Ontario, Canada-based design engineer Jeff Barnard, P.Eng. for Barnard Hydro Solutions Inc. Torque limiters were sold to the hoist system designer and supplier contracted Barnard Hydro Solutions — Municipal Treatment Equipment based in Golden, Colo. Image courtesy of Murray McCaig of Municipal Treatment Equipment.

The torque limiters also protect the design’s actuators when the latter are engaged to raise the grates in the event of a jam.

Barnard Hydro Solutions Inc. | barnardhsi.com

Municipal Treatment Equipment Inc. | municipaltreatment.com

Mach III Clutch Inc. | machiii.com

What is pitch in the context of conveyors?

February 19, 2019 By Danielle Collins Leave a Comment

Roller chains are one of the most common types of transport media for conveying systems. And while they’re available in many designs and variations to meet different application requirements, they all have one thing in common:

To specify a roller chain, you need three basic dimensions: chain pitch, roller diameter, and width between inner link plates.

Roller chains are specified by three main parameters: pitch, roller diameter, and width between inner links. Chains that have identical dimensions in these three dimensions will work on the same sprockets.
Image credit: Kobo USA

In general terms, pitch can be specified with reference to any feature — such as a hole or an edge — that is repeatable on each adjacent part. In terms of conveyor chain, pitch is usually defined as the distance between links, as measured from the center of the roller pin on one link to the center of the roller pin on the next link.

Note that some precision link conveyors refer to the pitch as the “link size.”

: Image credits: Motion Index Drives (top) and DESTACO (bottom)

The pitch of a conveyor chain or link is a determining factor for several performance characteristics of the conveyor. For example, there’s an inverse relationship between sprocket speed and chain pitch. Smaller pitch chains generally allow the sprocket to run at a higher rotational speed.

n = sprocket speed (rpm)

V = chain speed (m/min)

P = chain pitch (mm)

N = number of sprocket teeth

The smaller the chain pitch, the higher the permissible rotational speed of the sprocket.
Image credit: Senqcia

It’s also important to note that the smaller the pitch, the more teeth will be needed on the chain sprocket. And a higher number of sprocket teeth means that more chain links will be engaged during motion. This allows the chain to travel with less speed fluctuation and a smaller articulating angle, producing less vibration and better smoothness of motion. More sprocket-link engagement also provides less wear between the chain bushing and pin, meaning longer life of the chain. For these reasons, manufacturers generally recommend using the smallest chain pitch that satisfies the application conditions.

Wear to the pins and bushings can also cause the pitch to elongate. Manufacturers typically recommend replacing the chain when the extension of the pitch length reaches 2 to 3 percent of the normal pitch value.

Elongation of the pitch length is caused by wear to the pins and bushings. Choosing a chain with a smaller pitch can reduce the amount of wear, and therefore, the amount of pitch elongation.
Image credit: The Diamond Chain Company