Specifications_for_22_Foot_Dedicated_Runway_Broom_Head.docx

Specifications for 22 Foot Dedicated Runway Broom Head

GENERAL

These specifications contemplate the furnishing and delivery of one (1) NEW HEAVY DUTY, HIGH PERFORMANCE, FRONT MOUNT DEDICATED RUNWAY BROOM HEAD ATTACHMENT and indicate in general the type, size and quality desired. It is designated to be mounted to an existing Oshkosh Truck H Series Chassis (164” wheelbase) with M-B Companies auxiliary engine and controls.

The broom head shall provide a swept path of 18 feet when angled. It shall be 46 inches in diameter and be capable of producing 2600 Ft-Lbs of torque and 475 RPM. The broom head shall be hydrostatic drive with infinitely variable speed hydraulic pumps and fixed displacement motors. The broom shall have the ability to remove snow, ice, slush, sand and other debris at rated speeds up to 40 MPH depending on conditions. To confirm this, the following must be supplied with the bid.

The exact proposed broom drive power system components including gearboxes, and hydrostatic motors must have in field proven experience. No prototypes shall be allowed. The location and serial number along with contact and phone number of at least five airports must be supplied with the bid.

Engineering hydraulic power calculations confirming the broom speed and available torque values must be supplied with the bid. This includes sizes and specifications of all components from the engine to the broom shaft including specification sheets for the broom hydrostatic pumps and motors showing type, size, and manufacture. Efficiency losses must also be accounted for. The calculations must be understandable, complete, logical, and in a mathematical order per the Society of Automotive Engineers (SAE) and the Fluid Power Society standard formulas and practices. The burdened of proof is the responsibility of the bidder.

BROOM HITCH

The broom hitch shall provide low friction, free flotation, shock absorbing, and weight transfer for the broom head.

The low friction, free flotation is required so that it is independent of broom chassis for vibrations and bounce considerations and to accommodate surface irregularities. A parallel arm system with four horizontal pins shall be used. The two arms shall be box construction for torsional stiffness with 2-inch diameter pins on greaseable low friction bushings, DX prelubricated type (no metal on metal).

To maximize vehicle tractive effort, braking, steerability, and overall handling of the broom chassis, the broom chassis shall carry approximately 65% of the broom weight by utilizing a weight transfer system. A pair of hydraulic cylinders shall support the parallel arms of the hitch. Pressure in the hydraulic cylinders provides the lift necessary to transfer approximately 65% of the broom weight to the chassis. A control valve adjusts the oil in and out of the cylinders to provide the same weight transfer no matter what the surface irregularities. The vertical stroke of the cylinders and thus the hitch shall be 12” minimum.

The pair of hydraulic cylinders shall also “free float and dampen” the parallel arms of the hitch to minimize broom bounce at high vehicle speeds. The broom hitch must have hydraulic cylinders to provide an active shock absorbing systems.

For visibility, vehicle dynamics, and broom bounce reasons, the maximum horizontal distance from the chassis front axle centerline to the broom centerline in the bulldoze position shall be 10’-10”

BROOM ANGLE

The broom head shall be capable of swinging 35 degrees maximum left or right, selectable from an operator’s joystick. Using a longer broom than specified to accommodate swept path for larger swing angles is unacceptable due to storage and maneuverability reasons. The broom pattern shall not vary more than 0.5 in..The swing shall be accomplished by means of dual swing arms with four (4) pivot points, which ensures the weight of the broom head remains approximately on the chassis centerline regardless of the position of the broom head.ches end to end for the whole width of the broom whether swung left or right. The bearing mechanism shall allow frictionless motion through the swing and shall be accomplished by utilizing four vertical parallel shafts at least 2.5 inches in diameter at each end of both swing arms. The swing arms themselves shall be made from formed steel plate and machined steel tubing with greaseable low friction bushings, DX prelubricated type (no metal on metal).

BROOM OSCILLATION

The broom oscillation shall provide true flotation left to right for the broom head so that it is independent of broom chassis to accommodate surface irregularities and thus minimize brush pattern variation during operation. It shall have at least 8 degrees (+4, - of free floating oscillation from left to right. The ability of the broom head to oscillate shall be provided by means of a spherical bearing assembly and low friction nylon pads.

BROOM ELEVATION AND BRUSH PATTERN ADJUSTMENT

The broom head lift shall be achieved utilizing two 4 inch diameter hydraulic lift cylinders, one on each end of the broom frame, controlled by the operator’s joystick. The lift cylinders shall be equipped with a counterbalance valve, which prevents the broom head from creeping down. The pivoting action shall have adequate stroke to achieve ground clearance during transport when not in use.

A linkage attached to the broom lift cylinders shall also provide the brush pattern adjustment mechanism. The linkage shall activate a limit switch, which controls the cylinders’ valve limiting the down travel of the two lift cylinders. A thumbscrew shall adjust the linkage / limit switch relationship, thus allowing brush pattern adjustment. A toggle switch for remote broom lift control and pattern confirmation shall also be provided. A rubber latched, weatherproof control box housing the microswitch, linkage, thumbscrew and toggleswitch shall be located behind the broom head allowing easy, repeatable pattern adjustment from a standing position. Returning to operator’s cab to confirm pattern adjustment is unacceptable. For safety reasons the operator cannot be positioned under or near the broom head to make the pattern adjustment. The brush pattern adjustment process shall be accomplished without the use of tools.

AUTOMATIC BROOM PATTERN CONTROL

The broom head shall have a position sensor compatible with the onboard control system to provide automatic brush pattern control as described below.

In addition to manual brush pattern adjustment, there shall be automatic broom pattern control. A time based system shall be used to readjust the broom pattern by counting the time in the broom down position. When the preset time is reached, the broom head will index down a preset amount. At that time the timer is reset and restarts counting.

Time running in the up mode is not counted. Manually adjusting the pattern from the cab or broom head will reset the timer.

A manager controlled activation / deactivation setting shall allow operator to adjust broom pattern from inside the cab when activated. Manual adjustment (Push a button) increases the pattern in predetermined increments. Same for pattern decrease. These broom pattern adjustments can be achieved in the cab while moving and without raising the broom head. There shall be an additional pattern control switch at the broom head for control from outside.

BROOM HEAD

The brush itself shall be 46 inches in diameter and 22 feet long comprised of two 11 foot sections. The broom head frame must sustain the loads imposed by the snow removal capacity of the unit. It shall be fabricated from 6.5 inch diameter steel tube in tube design with 0.44 inch walls and include provisions for grease between the mating surfaces. The hydrostatic broom drive shall be dual end drive. Broom drive system shall consume 40.26 cubic inches of oil per revolution of the broom core.

Two high-speed hydrostatic motors (Sauer-Danfoss 90 series type) each connected to a planetary reduction gearbox shall be mounted within the inner diameter of the broom cores outer ends to minimize overall width. The motor gearbox connections shall utilize a static o-ring seal, wet spline type. No dynamic seal shall be used for reliability purposes. The motors shall not support the broom core loads and the planetary gear box shall be hydraulic oil bath lubricated (case flushing type).

Speed of broom shall be infinitely variable from 0 to 475 RPM. Available torque at the broom shaft shall be 2600 ft-lbs at maximum hydraulic pressure of 5000 psi for maximum snow moving capabilities. Engineering hydraulic power calculations confirming these values must be provided with the bid. Power shall be transmitted to the broom core from the gearboxes utilizing keyed tapered hubs to prevent any looseness in the connection for vibration concerns and high strength molded urethane drive cogs into replaceable hardened steel core drive receivers of the core. Hardened steel pilot plates shall support the radial loads. A maximum 2 inch gap between broom core sections shall be obtained by using a center bearing assembly utilizing the same components as the drive ends. The center bearings shall be encased in a sealed housing and be provided with oil bath lubrication. Manual greasing of bearings is unacceptable. The left and right side core sections shall be connected to each other by a center shaft so the two sections rotate at the same speed, and that the power produced by each of the end drive assemblies is transmitted across the full length of the core assembly.

The broom end plates shall be steel fabricated using 0.38 inch thick welded steel plate construction with 14 inch diameter, 0.38 inch thick steel tube for mounting the broom drive gearboxes. The end plates shall be reinforced horizontally and vertically using, 2” x 6” structural rectangular tubing on the inside and 3” x 6.5” formed channel on the outside. The broom end plates shall be secured to broom frame with four 1 inch diameter grade 5 bolts.

The unbolted end plates shall slide outward to allow easy access for core and bristle replacement. The slide mechanism shall be 4.5 inch round telescoping tube in tube design. A second 2 inch square tube shall slide on a plastic slide providing additional support and allowing repeatable location of brush centerline alignment during broom core remove and replace operations.

BROOM CORES

The two core sections must be split core design for easy handling. The two cassette type core sections must sustain the loads imposed by the snow removal capacity of the unit. The aluminum rails shall be hard coat anodized. There shall be a minimum of 28 rows of poly cassette bristles for maximum snow moving capabilities and complete or full bristles around the entire circumference. No gaps around the circumference between the rows are permissible. The drive receivers shall be replaceable hardened steel. Each core shall be individually dynamically balanced to acceptable values at rated RPM. The cassette bristles shall be United and SIB cassette compatible.

BROOM CASTERS

There shall be four single tire caster assemblies. Since a weight transfer broom hitch shall be utilized, the chassis carries approximately 65% of the broom weight. The broom casters shall carry the remaining weight of the broom head. Each caster assembly shall be free to rotate 360 degrees. The radial pneumatic tires shall be 180/70R8 16 ply. Spring-loaded adjustable automotive type disk brake shall be supplied per caster to prevent caster shimmy at all sweeping speeds. Caster hubs shall be oil filled to provide oil bath lubrication to the caster bearings. No greasing necessary or allowed. The caster assembly shall be non suspension type allowing the brush to follow the ground contours as close as possible. The broom head caster support shall be mounted to the main broom frame by means of welded brackets constructed of 0.5 inch steel plate, minimum. The steel caster assembly shall be attached to the broom head caster support by means of four bolts for serviceability. The caster axle shall be supported by the caster mounting body constructed of 0.63 inch plate.

BROOM HOOD

The broom hood shall shield the top half of the brush completely and fabricated from heavy-duty 10-gage sheet steel securely bolted to the broom frame. It shall be nonclog design to prevent ice buildup during freezing slush removal operations at rated speeds. It shall provide the necessary quick access to the brush for replacement of bristles and for inspection. There shall be an adjustable and replaceable stripper bar across the front of the broom to prevent snow carryover. The stripper bar shall be near tangential to the broom outside diameter.

A smooth curved scoop hood shall be incorporated across the full length of the broom. The stripper bar shall be attached to this scoop hood. It shall be connected to but move independent of the stationary hood. A snow deflector shall be mounted on the front of the scoop. Two hydraulic cylinders spaced appropriately along the length of the deflector shall adjust the angle of the defector with respect to the scoop. The deflector angle shall be controlled and adjusted from the operator's cab. The result is a smooth, efficient, and controlled flow of the snow leaving the bristle. The stripper bar, the scoop hood, and the deflector structure shall have no abruption to a smooth flow at any broom / bristle diameter or at any deflector angle.

The adjustment to bristle diameter wear shall be performed using two mechanical acme thread jacks, one each end of the scoop and broom frame. The adjustment shall position the stripper bar to the bristle diameter.

This scoop design is required for efficient stripping of the snow off the bristles to prevent carryover, especially with the high performance snow moving capacity specifications of the bid. No substitutes are allowed.

SNOW SHED HOOD

Hydraulic pivot tilt to remove snow that has deposited on top during sweeping operations. Snow shed hood is in addition to the standard hood…both. Skeletal steel framework construction with a black polyethylene cover bolted in place. Positive prevention of any operator error damage to bristles or other components. Tilt operational while the broom is rotating…no stopping. Tilt rotate forward in excess of 100 degrees. Positive stowed position against poly supports. The snowshed hood shall cover the entire length of the broom hood without interruptions for the most efficient snow removing capabilities. When in the automatic control mode, the hood shall lift and lower with one touch of the control switch.

HYDRAULIC SYSTEM

All hoses for all systems shall be properly sized and strength to work with the pressure and volume of oil required. All hydraulic positioning functions (broom head lift, broom head swing, deflector) shall be equipped with a hydraulic position locking system. A counterbalance valve shall be used for the broom lift and a pilot operated check valve for the other functions. All hydraulic functions of the broom shall be electric over hydraulic valving. Piloted operated check valves shall be installed for the broom swing left and right, deflector up and down. Fluid and components shall be design for temperature to –20 degrees F ambient cold start.

BROOM HEAD VIBRATOR

Attached to the broom head shall be a dump truck body vibrator to shake snow and ice accumulation off the broom head, 12 volt “Cougar” type or equivalent. 3000 pounds thrust impact force minimum. The vibrator shall be cab controlled with on / off style switch.

FINISH

Prior to application of the primer coat, the surfaces shall be adequately cleaned. The prime coat shall be an epoxy type. Two polyester urethane paint finish coats shall be applied with no imperfections including fish eyes. The entire broom head shall be low gloss black to reduce glare for the operator and to aid in melting ice and snow.

Owner’s Manual The successful bidder shall provide the following product documentation and support information on CD upon delivery:

Operation, Maintenance, and Troubleshooting manual Supplied equipment manual Parts manual identifying every part on the unit including schematics for electrical and hydraulic systems.

WARRANTY

The equipment provided shall be warranted against defective materials and workmanship for a period of 12 months after the machine is delivered. Warranty includes replacement or repair of defective parts or material and the associated labor to perform the repairs