Ernest Industries
Shortstop 3.5 Concrete Mixer Specifications
Model SHORTSTOP 3.5 ®
General The unit is a self-contained transit-type drum mixer complete with planetary gear reduced drive, hydraulic drive system powered by chassis engine or transmission, self contained water system for slump control and wash down.  Equipped with removable chute assemblies for placing wet concrete and the unit is capable of agitating and transporting 3.5 cubic yards of concrete at a reasonable slump.  Operator controls are situated on the rear of the unit and in chassis cab for constant drum speed and direction.  The drum is capable of 18RPM at 2500 engine RPM in both directions.
Dimensions The mixer body has the following dimensions:
OAL :152” (excluding chutes)
OAW: 62”
OAH: 68”
Weight Approximately 3,450 lbs less water and concrete
Drive 22:1 planetary drive, designed specifically for a transit concrete mixer.  The drive unit features 9 degrees oscillation to compensate for drum misalignment, heavy-duty cast iron housing with ball bearings, ensuring many years of reliable service.
Hydraulic motor, directly coupled to reducer with oscillating mount design, 5000 psi maximum operating pressure.
Hydraulic pump, pressure compensated pump, capable of generating 3000 psi; directional valve mounted on pump.  Pump is a closed-loop system with charge pump and charge filter. Pump can be coupled directly to truck engine crankshaft (FPTO), engine flywheel PTO drive (RPTO), live power automatic transmission mounted (Allison RDS 3000, 3500 or 4500) (RPTO).
Hydraulic reservoir, is fabricated from ¼” carbon steel plate and features one 6” diameter inspection cover.  The reservoir is equipped with a 1” NPT canister type return  filter and a stainless steel suction strainer with  bypass.  A sight level gauge and vented fill cap is provided.  All high pressure hose and fittings are rated at 2,500 psi and equipped with JIC type fittings. 18 gallon capacity. 
Drum 1/4” thick spun steel drum head, with reinforced machined flange to mount gear drive.  Fabricated from 3/16 high-strength carbon steel,  the drum is fully welded inside and out.  A 1-1/4” thick X 2-1/2” wide carbon steel track ring is welded to the rear of the drum.  Charging/discharge fins: two separate helix, 2.5 revolution pitch over length of drum, 3/16 high strength carbon steel.  In the belly of the drum, the fins are 12” tapering to 8” at the discharge.  Fins feature hardened steel rebar welded to the tips and fold over fins at discharge end of  the drum. The fins are fully welded to drum and equipped with wash holes approximately 12” apart. Man way: one 22” X 28” is located on front of drum to access interior.  The cover is bolted to main drum with twenty  two ½” bolts.  The rear of the drum is supported by two carrier bearings, mounted on an adjustable pedestal. The bearings feature a hardened exterior with tapered roller bearings and lip seals for long life.  The bearings are further protected by a felt disk on each side to prevent direct water spray.  Each bearing features a convenient panel mounted grease whip.
Frame Heavy-duty structural and plate steel frame electrically welded at all joints.  The mixer is attached to the chassis with sixteen 5/8 grade 8 bolts.  Eight of the sixteen bolts are equipped with heavy-duty springs to permit flexing of the chassis frame independent of the mixer frame.
Discharge Chute A 24” wide discharge chute at drum, tapering to 12” wide on a rotating pedestal is provided. One each permanently mounted extension chute 34” long and two each removable chutes 34” long are standard equipment.  A structural steel chute holder is provided to hold the two removable chutes.  The holder is bolted to the chassis frame and features rubber straps to hold chutes while in transit.  Manual hydraulic pump and cylinder is provided to raise and lower the rear chute assembly.  Locking mechanism for the chute assembly is operable from either side of the unit and features a transport safety lock.
Access Platform Structural steel tube ladder leads to a non skid metal platform fully enclosed in square tube railing.
Water System 80 gallon zero pressure water tank is located on the front of the mixer frame.  Sight gauges and fill ports are provided on both sides of tank.  A 12VDC powered roller pump delivers water at a rate of 4 GPM with a maximum pressure of 45 psi.  System includes: 25’ hose; water nozzle, hose hook, water filter, tank drains.  Plumbing is provided to inject water into rotating drum from the rear operations station for slump control.
Fenders Heavy-duty polyethylene fenders with structural steel brackets are provided.  Attached to each fender is one mud flap.
Controls Electronic controls for speed and direction of drum, water pump (on/off) and optional power discharge chute control are located in the chassis cab and rear operator’s station. The controls are mounted in a waterproof aluminum box and feature MIL spec waterproof switches. The electrical system is equipped with a re-settable 30 amp circuit breaker.
Finish Unit is completely coated with self-etching primer and finished coated with a two component urethane finish. Mixers are standard one color white.
Parts and Service Manufacturer carries a complete inventory of parts available for shipment within 24 hours.
Warranty Mixer body carries a one year warranty against defective parts and workmanship. 
For details see: Terms of Sale and Warranty
Operators Manual One complete operators & parts manual will be supplied with the unit.  All operators of the mixer should read the operators manual in full prior to operation of the mixer. Serious injury or death may result from the improper or misuse of the mixer body. Questions concerning the operation of the Shortstop Mixers call (937) 325-9851, email:
Specifications In our continuing effort to make improvements, specifications are subject to change without notification.
Chassis Units can be installed on a conventional or cab forward chassis.  Chassis requires  a minimum 16,000-lb payload if the mixer is to be operated at full 3.5 yard capacity. Generally, a 26,000-lb GVW chassis will accommodate the mixer.  Be sure to size the chassis to meet your DOT and chassis payload requirements. Final capacity of the mixer is based on the combined weight of mixer & chassis and weights of ready mixed concrete recipes. See “Chassis Information” on website or contact Ernest Industries for more information on chassis requirements.
SS3.5X Standard mixer unit less mounting to chassis and excluding hydraulic hoses, hydraulic oil, fenders, pump drive shaft.
EXC3.5 Export Crating. Mixer less chassis fully crated in 4” X 4” wood frame and covered with 7/16 OSB wood.  Frame designed suitable for moving loaded crate with forklift.
Optional Equipment
OE3.5-1 Power discharge chute control complete with12VDC hydraulic pump cylinder assembly for automatic rear chute control with controls located in chassis cab and rear operators’ station.
OE3.5-2 Night lights, 4 each high output halogen lights to illuminate rear discharge area and charging  chute. 
OE3.5-3 Charging chute extension, for loading from standard height batch plant, T-6 Aluminum construction, easily removable at jobsite.
OE3.5-4 Pressurized water tank, 75 gallon (carbon steel) in lieu of zero pressure and pump. Chassis with air brakes is required.
OE3.5-5 Pressurized water tank, 75 gallon (aluminum) in lieu of zero pressure and pump. Chassis with air brakes is required. (recommended for colored concrete)
OE3.5-6 Tool boxes, 18” X 24” X 36” with keyed lock, mounted to chassis frame..  (other sizes available upon request)
OE3.5-7 Rotation counter, manual, re-settable, mounted drivers side at planetary gear reducer.
**May be required for delivery to municipal, state and highway accounts.  
OE3.5-8 Electronic speed and rotation counter, LED display located in chassis cab.
**May be required for delivery to municipal, state & highway accounts. 
OE3.5-9 Self contained engine/ hydraulic system , gasoline, diesel, electric.
OE3.5-10 Stationary stand for pre-cast type operations.
OE3.5-11 Additional chute assembly, available in 34” sections.
OE3.5-12 Fold over chute, 12” rigid steel extension, 90 degrees. 
OE3.5-13 Fold over chute, 12” rigid steel extension with 36” flexible rubber extension.
OE3.5-14 Electronic gallon, LED counter reads to nearest gallon and re-settable.
OE3.5-15 Frame mounted holder for charge chute extension.
OE3.5-16 Pneumatic chute lock in lieu of standard manual lock.  Requires chassis with air brakes.
OE3.5-17 Front frame extensions for Ford, GM & International, includes harmonic balancer adapter but does not include modifications to radiator if required.
OE3.5-18 REPTO for Allison RDS 3000, 3500 & 4500 automatic transmissions includes Muncy PTO adapter, brackets and driveline.
OE3.5-19 REPTO for UD 2600/Allison Automatic, includes fabricated hydraulic pump mounting bracket, drive line, actuator and guard for hydraulic pump.
OE3.5-20 Wireless remote controls in lieu of hard wired control box. A water proof receiver will be mounted on the mixer frame under the rear tower.  A transmitter shall be provided to control the speed/direction of the drum and power discharge chute.  The receiver will get power from the 12VDC charging system on the diesel engine and the transmitter shall be powered by two AA batteries.   The operating range is 250’.
  Hook Lift System: See SS3.5 Hook Lift Configuration