Presto P4 Load Leveler

The P4^™ Load Leveler improves worker productivity and reduces fatigue. Its platform lowers to floor height so that pallets can be placed and removed using a hand pallet truck.

In loading operations, a pallet is placed on the platform and the platform is raised by hydraulic power to its full “UP” position. As goods are loaded onto the pallet, the platform is lowered so that each succeeding tier of goods can be loaded at the same height.

When unloading pallets, the platform starts at its lowest height and is progressively raised so that each succeeding tier of goods can be removed at the same height.

The P4 Load Leveler can be accessed from all four sides. Units are equipped with a photoelectric toe guard which will stop downward travel if the beam is interrupted.

The units have capacities up to 4000 lbs., making them suitable for most pallet loads that can be moved with hand equipment.

For all your work positioning equipment visit www.presto-lift.com

Belt Conveyor Overview

Troughed Bed Belt Conveyors
This slider bed belt conveyor includes a built-in side guard with its troughed frame design. Perhaps the most popular use of this conveyor is to convey “trash” or “scrap” to dumpsters or other containers for disposal (or recycling!) It is also commonly utilized containers for handling scrap cardboard, packing materials, and steel slugs. These units can easily be modified with a higher integral frame depth which will provide higher built-in guarding.

Slider Bed Belt Conveyors
The most popular of all powered conveyors remains the slider bed belt conveyor. This unit is very versatile, able to convey a wide variety of products. Many objects carried by the slider bed belt conveyor have uneven or difficult surfaces to convey for a live roller conveyor or may be very small or a various group of sizes — again presenting a challenge for a live roller conveyor to transport. Typical applications for the slider bed include packing, testing, inspecting, sorting, transportation and assembly.

Roller Bed Belt Conveyors
The roller bed is most commonly used for transporting heavier unit loads with low horsepower requirements. The decreased belt-to-transport-surface friction is much lower on roller bed belt conveyors than slider bed belt conveyors. (5% on roller beds compared to 30% on slider beds). Typical applications for the roller bed are packing, testing, inspecting, transportation and assembly. NOTE: Two rollers are required under the product at all times.

Inclined Floor-To-Floor Belt Conveyors
Floor-to-floor belt conveyors are used to transport a product up or down at 0 to 30 degrees. The maximum degree a product will convey is  determined by the height, length and bottom conveying surface of the product. Single or double nose-overs are standard components. Chain driven feeders offer package separation or metering since it is slave driven from the inclined portion. Integral feeders are generally easier to track than chain driven feeders. Always add feeder when transferring product from gravity conveyors onto the inclined belt unit. Feeder length is normally equivalent to the longest product conveyed.

Belt Driven Live Roller Conveyors
Belt driven live roller conveyors are ideally suited for horizontal conveying of items where transfers, side loading, unloading, or temporary accumulation is required. Belt driven live rollers may be used when conveying heavier product loads. Also, a product slides across a roller much easier than a belt when loading or unloading from the side of a conveyor (assuming no transfer device is utilized) A number of 90 degree transfers may be mounted into belt driven live rollers to accommodate removal of products into operator work areas or onto perpendicular spur lines for accumulation, for example.

Belt Driven Live Roller Curves/Spurs
Belt driven live roller curves and spurs handle light and medium loads. These units are most commonly “slave-driven” from belt driven live roller conveyors to minimize number of drives required. The rollers on these units are driven by a tough B-section V-Belt. Curves are standard in both 45 degrees and 90 degree, but are also available in various other configurations – 30, 60  and 180 degrees are common. Curve/spur combination units provide merging/diverging capability for delivery to or from spur lines and are available in 45/45 degree and 60/30 degree. The 60/30 degree unit is desirable to use as a converging spur with its 30 degree spur.

Belt Driven Live Roller Minimum Pressure Accumulators
Belt driven live roller minimum pressure accumulators offer both transportation and accumulation features. Pneumatic or manual roller stops are used to stop the product flow while packages accumulate. The stops are used to stop the product flow while packages accumulate.  The design of minimum pressure accumulators allows the drive belt tension to be variably adjusted so that the amount of back pressure is decreased. Minimum pressure accumulators work most effectively in temporary situations with long lines of accumulation, zero pressure accumulation conveyors should be utilized. Minimum pressure accumulators are ideal for use with belt driven live roller curves/spurs and when packages have to be stopped temporarily for assembly line operations.

Line Shaft Driven Live Roller Conveyors
The line shaft driven live roller conveyor is designed to conveyor, accumulate and transport relatively light products. Many sections and acessesories may be coupled to one drive which reduces the overall number of drives required and also, eliminates many electrical controls. A maximum drive capacity of 15 lbs. per roller is a quick method to immediately decide whether line shaft conveyor is a candidate for a particular  application. In addition, line shaft should NOT be used when very slow speeds are required (less than 15 fpm. Roach is the only line shaft conveyor manufacturer to implent use of flexible jaw coupling and hytrel inserts which have drastically reduced installation and maintance time on this popular unit.

Line Shaft Driven Live Roller Curves/Spurs/Gates
Line shaft driven live roller curves and accessories are designed to convey, accumulate and transport relatively light products. These accessories may be coupled to one drive section thus reducing the overall number of drives required to operate. Like straight line shaft sections, drive capacity is 15 lbs. per roller. The standard durometer of line shaft bands i 85 durometer. In certain instances, drive bands are changed in order to provide additional driving force for line shaft conveyors.

For all your conveyor needs visit www.conveyor-parts.com

Chain Driven Live Roller Conveyors

Chain driven live roller conveyors are specifically designed to convey heavy loads or pallets for transferring, loading, or unloading. These conveyors are especially suited for carrying loads in oily conditions and may be adapted for their use in washdown applications, freezers, ovens and in the presence of contaminates. Remember that special provisions are required when placing ANY conveyor in such hazardous environments. Modifications such as zinc-plating or galvanizing of rollers and/or frames, special bearings or modified grease bearings or special gearmotors may be required. Always consult Material Flow in such applications for guidance. Use roller-to-roller chain driven live rollers for very heavy loads such as filled drums, frequent start/stop situations and reversible applications involving heavy loads. Roller-to-roller driven units also provide an overall lower unit elevation since no underneath mounted chain take-up mechanism is required. When continuous loading approaches 100 lbs./ft. use a single strand type chain driven live roller unit.

For all your conveyor needs visit www.conveyor-parts.com

Presto Lift Stik Series

Sleek, stylish, ergonomic work positioners.

The Lift Stik™ from Presto Lifts may be the most versatile lifter transporter ever built. Its innovative compact design distributes the load evenly over four oversized casters that roll easily over thresholds and uneven floors.

Lift is achieved by a powered, continuous chain in the Lift Stik’s™ single mast. The narrow mast design provides unmatched visibility. A hand-held push-button remote allows the operator to lift or lower the platform from any side of the unit and at dual speeds for safe, efficient control. Because the lift is mechanical and not hydraulic, there is zero drift and no possibility of messy hydraulic leaks. The battery-charge indicator is mounted centrally on the push handle in direct view, and an auto-cutoff function prevents overcharging.

Ideal for stockrooms, assembly areas, laboratories, offices, and retail stores, Lift Stiks™ are available in four models with load capacities ranging from 185 to 445 lbs. Maximum lift heights of the platform/forks range from 52” to 65”. The unit’s ergonomic contoured “sponge grip” handles can be adjusted to accommodate operators of different heights.

Units are available with either platform or fork design.

To purchas a Presto-Lift visit www.presto-lift.com

Conveyor Glossary

You may see the following terms when purchasing or looking at conveyor.

Accessibility: The ease of access or approach to equipment for operation, inspection, maintenance and lubrication.

Accumulation Conveyor: Any conveyor designed to permit accumulation of packages, objects or carriers. May be roller, live roller or belt.

Adjustable Speed Drive: A drive or power transmission mechanism that permits variation of its speed within design limits.

Arc of Contact: The angular wrap (in degrees) of a belt around a pulley.

Assembly Conveyor: Any type of conveyor adapeted to convey assemblies or parts through a series of progressive assembly operations.

Ball Transfer Table: A group of ball transfers over which flat surfaced objects may be moved in any direction.

Bare Pulley: A pulley which does not have the surface of its faced covered or lagged.

Bed: The part of a conveyor upon which the load or carying medium rests or slides while being conveyed.

Belt Conveyor: An endless belt operating over suitable, drive, tail end and bend terminals and over belt idlers (rollers) or slider bed for handling bulk materials, packages, or objects placed directly upon the belt.

Belt Scraper: A blad or blades cause to bear against the moving conveyor belt for the purpose of removing materials sticking to the conveyor belt.

Belt Tracking Device: May be required to maintain proper tracking of belt. Assembly consists of Cam Rollers and “clamping” device to prevent belt return from moving off of the central path.

Booster Conveyor: Any type of powered conveyor used to regain elevation lost in gravity roller or wheel conveyor lines.

Brake: A device for slowing down conveyor or components for controlling overspeed du to the action of gravity.

Brake Belt: A stop-feeder device for indxing, spacing, or controlling unit loads.

Capacity: The number of pieces of a defined size, volume of material, or weight of material, that can be handled by a conveyor in a unit of time.

Ceiling Hangers: A support fastened from an overhead frame work to position and carry loads.

Chain Conveyor: Any type of conveyor in which one or more chains act as the conveying element.

Chain Driven Feeder: Generally utilizes PVC smooth surface belt. It is slave driven from the inclined (or declined) unit. It can also be used in minimum elevation applications.

Chain Guard: A covering for drive or conveyor chains for safety purposes.

Cleat: An attachment fastened to the conveying medium to act as a support to help propel material, parts, or packages along the normal path of conveyor travel.

Clutch: A device to permit engagement or disengagement of drive mechanism while in motion or at rest.

Constant Speed Drive: A drive with no provision for variable speed or a drive with the characteristics necessary to maintain a constant speed.

Control: The system governming the starting, stopping, direction of motion, acceleration, speed, and function of the moving member in a predetermined manner.

Control Enclosure: The type of construction of the housing or case which encloses a control component. The common  types of enclosures are designated by NEMA.

Conveyor: A horizontal, inclined or vertical device for moving or transporting packages or objects in a path predetermined by the design of the device and having points of loading and discharge fiex or selective.

Conveyor Belt: A belt used to carry materials and transmit the power required to move the load being conveyed.

Crown: The rate of taper of a pulley face that is defined as the amount by which the diameter at the center of the face exceeds the diameter at the edge.

Curve: A conveyor section used to change the direction of travel.

Dead Load: The combined weight of the conveyor elements and supports.

Dishcharge End: The end of a conveyor usually where the material is fed off the unit.

Diverging Section: A section of roller or wheel conveyor which makes a connection for diverting articles from a main line to one or more branches.

Diverter: A mechanism used to alter the path of a unit load for traffic control or sortation purposes. Also known as a deflector or plow.

Double Roller Curve: Also known as differntial rollers. Uses “split roller” design to conveyo product. Conveyability of product improves with split or double roller design. Guard rails should be used.

Drive: An assembly of the necessary structural, mechanical, and electrical parts which provide the motive power for a conveyor.

Drive Pulley: A pulley mounted on the drive shaft that transmits power to the belt with which it is in contact.

Drive Shaft: A main driving shaft on which conveyor sprockets, gears or pulleys are mounted. This shaft is connected to the drive unit through  a coupling, sprocket gear or other form of mechanical power transmission.

Durometer: A measure of the hardness of rubber or plastic material.

Escapement: In gravity or power operated package conveyor, a device to permit the release of packages on at a time on demand.

Explosion Proof: Equpment designed in accordance with existing codes and standards such that it will operate in a specified hazardous environment without causing an explosion.

Extendable Conveyor: Closely fitted plates positioned between the rollers of non-powered or powered roller conveyors.

Filler Plates: Closely fitted plates positioned between the rollers of non-powered or powered roller conveyor.

Flexible Coupling: A mechanical connector to transmit torque without slip and to accommodate misalignment between driven machine members.

Flow Rack: A tiered structure with multiple storage compartments with conveyors as the load supporting members.

Frame: The structure which supports the machinery components of a conveyor.

Gap Roller: Fills the space created when driven rollers cannot be located close enough to transport product. Gap rollers are generally required on chain driven live roller conveyors to convey small products.

Gate: A device or structure by means of which the flow of material may be stopped or regulated.

Grade: The rate of incline or decline in terms of degrees from the horizontal.

Guard: A covering or barricade for safety purposes such as gear, chain and nip guards.

Guard Rails: Members paralleling the path of a conveyor and limiting the product on the conveyor to movement in a defined path.

Herringbone Roller Conveyor: A roller conveyor consisting of two parallel series rollers having both series skewed.

Idler: A puley, sheave, sprocket or wheel around which a belt , cable or chain passes in changing direction of travel.

Knee Brace: A structural brace at an angular position to another structural component for the purpose of providing support and/or stability of the conveyor frame.

Lagging: A smooth or embossed covering or coating applied to a pulley to reduce belt slippage or wear, and prevent material build up.

Lagged Pulley: A pulley having the surface of its face covered with lagging.

Limit Switch: An electrical device by which the movement of a conveyor may be controlled within predetermined limits.

Line Shaft Conveyor: Roller conveyor with carrying rollers individually powered by “O” rings from a rotating shaft.

Live Roller Conveyor: A series of rollers over which objects are moved by the application of power to all or some of the rollers. The power transmitting medium is usually belting or a chain.

Metering Conveyor: In package handling, a short powered conveyor whose speed and motion are controlled to release unit loads at predetermined rate.

Nip Point / Pinch Point: A point at which a machine element moving in line meets a rotating element in such a manner that it is possible to nip, pinch, squeeze or entrap a person or object coming into contact with one of the two members.

Nose-Over: Curved or segmented frame sections having rollers properly spaced to provide a transition from incline to level or from level to decline.

Power Conveyor: Any type of conveyor which requires power to move its load.

Roller Conveyor: A series of rollers supported in a frame over which objects are advanced manually by gravity or power.

Rough Top Belt: A belt conveyor that is intentionally made with irregular ridges or projections to produce a broken surface for greater traction or carrying abilitities.

Screw Take-Up: A take-up assembly having provisions for manual adjustment by one or more screws to compensate for stretc, shrinkage or wear of a conveyoing or power transmission medium.

Shaft: A bar, usually of steel and usually round to support rotating parts or to transmit power.

Skatewheel Conveyor: A type of wheel conveyor making use of series of skatewheels mounted on common shafts or axles, or mounted on parallel spaced bars on individual axles.

Slat Conveyor: A conveyor employing one or more endless chain to which there are non-overlapping, non-interlocking spaced slats attached.  Slats may be constructed of various materials including steel and a variety of hardwoods.

Slider Bed: A stationary surface on which the carrying run of the belt conveyor slides.

Supports: Arrangements of members used to maintain the elveation or alignment of conveyor. Supports can take the form of ceiling hangers, floor supports, or brackets and can be either stationary or portable.

Tail Pulley: A pulley mounted at the tail end of a conveyor.

Take-Up: The assembly of the necessary structural and mechanical parts which provides the means to adjust the length of belts, cables, chains, etc., to compensate for stretch, shrinkage, or wear and to maintain proper tension.

Tapered Roller: A conical conveyor roller for use in a curve with end and intermediate diameters proportional to their distance from the center of the curve.

Tread Rollers: Rollers carrying the object or product being transported.

Troughed Bed Conveyor: A belt conveyor with the conveyor belt edges elevated on the carrying run to form a trough by conforming to the shape of the troughed carrying idlers or other supporting surface.

Wire Mesh Belt Conveyor: A flexible belt composed of a series of formed wires laterally connected, or of longitudinally articulated wires laterally connected for operation over straight face pulleys or sprockets.

For all your conveyor needs visit www.materialflow.com

Conveyor Safety Guidelines

A gravity conveyor bracket should always be used when connecting power conveyors to gravity conveyor to eliminate hazardous pinch or “nip” points. Always use gravity connector bracket with pop out roller to permanentely attach any gravity conveyor with pop out roller to permanentely attach any gravity conveyor to power conveyor. This simple connection eliminates hazardous pinch points that would otherwise exist by attaching a gravity conveyor directly to a powered belt unit.

Connector brackets are supplied as an optional component and are readily available. Present unit serial number and gravit model number (including width) when calling to order safety connector brackets, model CB.

Safety Pop Out Rollers

Inclusion of safety pop out rollers is an integral, critical design feature of belt driven live roller conveyors. The upper flange of the conveyor frame is slotted for rollers to “pop-out” of the frame if, for example, a hand became loadged in the tread rollers. This safety design must be included on units installed under 7′ top of roller elevation. If the unit is installed 7′ top of roller elevation and above (ceiling supported, etc. ) this pop out design must be eliminated. Rollers are retained in the frame by a “roller hold down angle” or they may be retained by a formed angle guard rail with 1 1/2″ flange width. Consult Material Flow for more information.

Safety Instructions

Do not operate conveyor with protective guards removed. This includes chain guards, belt guards, snub roller guards, center drive guards, line shaft guards and any other safety guard.

Do not walk, ride, climb or touch moving parts on a conveyor in operation.

Do not wear loose clothing or uncovered hair around conveyor.

Do not work near conveyor without knowing how  & where to shut off power.

Do not remove jammed product with conveyor running.

Do not replace parts or perform maintenance on conveyor, or moving conveyor parts, without first shutting OFF power to conveyor.

Do not connect gravity to powered conveyor without safety gravity connector brackets.

To prevent electrical shock, conveyor must be grounded, and have proper electrical connections in accordance with federal, state, and local codes.

Safety pop out rollers in conveyors installed above 7′ elevation must be retained by guard rail, clips, etc… Safety pop out rollers must be allowed to pop out when conveyors are installed at or below 7′ elevation.

It is the responsibility of conveyor end-user to comply with all safety standards including OSHA and other federal, state, and local codes or regulations. Placement of guards and other safety equipment in accordance with safety  standards is dependent upon the specific application and must be installed whenever appropriate.

Power Conveyor Inclines

Conveying objects up or down via inclined or declined belt conveyors is very common. Probably teh most asked question involves determining the maximum angle an object will convey. This varies from product-to-product depending on the configuration of the object being moved and on the carrying surface of the object. One package 12″ Wide x 12″ High x 24″ Long with a rough bottom conveying surface will convey at a higher grade than an object the exact same size with a smooth or slick bottom conveying surface.

Due to limited floor space and other conditions, an incline unit may require a greater angle than is recommended for the application. Some possible solutions include using a slided bed conveyor with a cleated belt. In this case,  center drive, nose-over and integral feeders must be removed from the unit. Another possible solution is to explore specialty incline belts such as the “sticky top” belt which may provide an improved carrying friction surface. Still yet, a Roach continous vertical conveyor or reciprocating vertical conveyor would another option to explore especially if floor space is very limited. Rates as high as 35 packages per minute are possible with a continous vertical conveyor.

CAUTION: Excercise extreme caution when conveying plastic tote pans. These objects often have “slick” bottom conveying surface and will require additional consideration.  Consult Material Flow for questions or specific requests.

Maximum Angle of Incline Formula

The following formula is a useful tool for quick reference in determining maximum angle of incline. Remember, when this formula is completed, the resulting answer requires additional consideration to ensure that the angle chosen will convey the specific product considering its bottom conveying surface. The formula yields the tangent of the incline application.

Tan “B” = 1/3 (Package Length) / Package Height

Vending Handtrucks

Moving a vending machine is no easy task, in fact it can be downright dangerous without the proper equipment. Most vending machine handtrucks feature a safety break and straps that prevent vending machines from sliding off the truck.  A variety of models are available in a wide range of capacities and styles.

For all your vending handtruck needs visit www.dutro-handtrucks.com

Power Stack Counterbalance Stacker

The versatile, fully powered PowerStak™ Counterbalance Stacker from Presto Lifts. works with any style pallet or skid and is ideal for servicing racks, loading/unloading trucks, feeding machinery, and other applications where straddle legs could get in the way.

With a load capacity of 1100 pounds, a load center of 15”, and a lift height of 62”, the unit has a short yet stable wheel base to maximize maneuverability in tight quarters on uneven floors and ramps. The tilt of the mast is adjustable. Overall height is 82”, overall width 32”. The forks are each 3” wide and 30” long. The PowerStak Counterbalance Stacker is loaded with ergonomic features.

The ergonomically designed handle puts all controls within easy reach for maximum operator comfort and convenience. Forward- and reverse-drive “thumb” switches are located on both sides of the handle to accommodate left-hand or right-hand operation. An auto-reversing “belly bump” switch protects operators from potential injury when walking the unit backwards, while an automatic brake immediately halts travel when the stacker is reversed. The polyurethane drive wheel is fully shrouded to protect the operator’s feet. Power is achieved via two maintenance-free 12-volt batteries. A 110-volt built-in charge is also a standard feature. Options include load backrests, a deep-cycle battery, and forged forks.

For all your material handling needs visit www.materialflow.com

Conveyor Operations

Load Characteristics: Surface condition of product should have a smooth and firm bottom for efficient conveyability.  As Specialty items such as rolls of cloth or carpet may be conveyed on a “troughed roller” arrangement which forces the object to run down the center of the conveyor. In this instance, use of solid formed guard rails is imperative.

Operating Conditions: Special conditions dictate any modifications required for normal unit operation. A conveyor used in a wet or wash down application, foundry, oven or freezer will require special features that normally would not be required when operated in a clean dry ambient room environment.

Roller Capacity: Once the number of rollers required to convey the minimum package length is determined, roller capacity must be determined. Divide the maximum weight per linear foot by the number of rollers required per foot. The minimum required capacity per roller results.

Example: 18″ long package weighs 800 lbs. 800 / 18 x 12 = 534 lbs. per foot.

534/4 = 134 lbs. minimum roller capacity for 3″ roller centers when a minimum  of  rollers are required to carry the minimum package length.

534/3 = 17 lbs. minimum roller capacity for 4″ roller centers when a minimum of 3 rollers are required to carry the minimum package length.

NOTE: Additional rollers (or high capacity rollers) are required to support load when product loading is unevenly distributed.

Frame Capacity: After the roller capacity is determined, unit frame capacity must be calculated. Multiply the maximum product loading per linear foot by the conveyor length to determine the required frame capacity. The minimum required frame capacity results.

Example: Max. product load per foot is 250 lbs.

250 lbs. / ft. max. load x 10 = 2500 lbs. total live load per 10′ section.

Shock Loading: Shock loading  (i.e. loading from fork truck, or dropping load onto conveyor) places a great deal of stress on both conveyor rollers and frame. Therefore in instances where conveyor is subject to shock loading, provisions must be made to deal with this high stress loading. Rollers with greater capacity, heavier duty rollers and/or heavier gauge frame construction is required to offset this special loading condition.

Curves:
A. Straight Face Rollers: Straight face rollers are recommended where packages of uniform size are conveyed and rubbing against guards is not objectionable. Package orientation may be affected.

B. Differential Rollers: Differential Rollers offer reduced package swerve (when compared to a straight roller curve) and packages travel more easily. Guard rail should be used.

C. Tapered Rollers: Tapered rollers are recommended above all others because of their improved carrying surface. They hold the package in relatively the same position through the entire curve. Guards are normally used on the outside curve rail.

Curve Radius: There are various methods used to identify the point where radius is measured on Roach curves. Curve radius locations vary by individual manufacturers.

Curve Width: Once the appropriate curve has been selected, curve width must be determined. Lengthy objects will require special consideration. As a general rule of thumb the package length should not exceed the inside radius dimension (this will not be a factor if the BF is wide enough). It is recommended there-fore, to maintain a greater inside radius than the longest package length conveyed.

Supports:
A. Tripods: Tripods are used on light duty conveyors in portable or temporary applications. Tripods are not recommended for application using medium duty conveyors. When installing tripods, the top channel of the tripod assembly rests in the frame conveyor cross brace.

B. Permanent Floor Supports: Permanent “H-type” floor supports are the most common means of supporting conveyors. A full support is used to span intermediate bed sections where adjoined and at each end of a unit. Additional supports are required only when additional capacity is required to support the frame in extreme conditions or when a normal support location is blocked by other machinery (or similar instances). Single leg permanent floor supports are also available.

C. Ceiling Hangers: Ceiling hangers are commonly used in high elevation applications or when it is not practical to install permanent floor supports (aisles, walkways, etc.)

CAUTION: When using ceiling hangers at 7′ and above installed elevation, it is imperative that high solid guard rail is used to hold product on conveyor and that safety pop out rollers are retained in the conveyor frame.

D. Polytier Supports:
When two or  more tiers of conveyor must be installed, use polytier supports. Each set of legs is supplied with cross pipes and one pair of knee braces (standard) to support multiple tiers of conveyors. In minimum elevation applications, hardware is available for installation at frame depth + 0.

E. Undertrussing:
For installation of some conveyors, a full support or ceiling hanger cannot be used to maintain necessary clearances underneath unit or for other. In these instances, use of unit undertrussing may be a viable alternative. Tow bed sections or a total of 32′ may be undertrussed.