Ernest Industries
Shortstop 3.5 HLC Concrete Mixer Specifications
General These specifications are intended to describe and define the minimum requirements for a  self-contained, drum type, transit concrete mixer installed on a hook lift frame capable of quick installation and removal from the chassis employing a hook lift on the chassis. The mixer shall be capable of agitating and transporting 3.5 cubic yards of concrete at a reasonable slump while firmly attached to the chassis.  The unit features a planetary reduced  hydraulic drive, hydraulic pump system powered by a 30 HP diesel engine, pressurized  water system for slump control and wash down. Operator controls are situated on the rear of the unit to control drum speed /direction, discharge chute height and engine throttle control. The mixer is equipped with removable chutes with a reach of over 12’ for placement of concrete.  The drum is capable of 18 RPM at 2,500 engine RPM in both directions.
Dimensions The mixer body has the following dimensions:
OAL :168” (excluding chutes)
OAW: 80”
OAH: 76”
Weight Approximately 5.250 lbs less water and concrete
Engine The mixer is powered by a Kubota model V1305 diesel engine.  The engine is rated at 29.1 continuous horsepower and is tier 4 emission approved.  The engine features  a 12VDC charging and starting system, 15 gallon fuel tank and Murphy low oil pressure/high water temperate automatic shutdown system.  The engine will be equipped with a two speed electronic throttle with controls at the rear operators control panel.  The engine  master control panel will feature a keyed switch, override switch for Murphy shutdown, tachometer and engine hour meter.  The engine will further be equipped with a 575 CCA battery and intake manifold glow plugs for cold starting.
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 output shaft, 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 shall be coupled directly to auxiliary diesel engine.
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. 
Hook Lift Frame The hook lift frame shall be a heavy duty  tubular steel construction, 2” X 8” long sils, 2” X 6”  “A” frame with 1/2” A36 gussets and tubular steel cross members. The frame shall be approximately 13’6” in length.  The frame shall be equipped with  two each 8” all steel wheel assemblies on the rear rigidly welded to the frame.  The concrete mixer frame shall be electrically welded to the hook lift frame creating a unitized framework.  The frame shall feature two ratchet strap assemblies welded to the front of the frame to secure the mixer frame to the chassis frame.  The ratchet straps will be 3” wide nylon and rated a minimum capacity of 3000# each.
Discharge Chute A 24” wide discharge chute at the 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 welded to the hook lift  frame and features rubber straps to hold chutes while in transit.  The discharge chute is equipped a single acting telescoping hydraulic cylinder, self contained 12VDC hydraulic pump and switch.  The discharge chute cylinder is controlled by a toggle switch located at the control panel.  The discharge chute is capable of pivoting 180 degrees and features a manual lock assembly with safety transport lock.
Access Platform Structural steel tube ladder leads to a grated steel platform with a square tube railing on three sides. The ladder shall fold and lock to permit loading and unloading via hook lift.
Water System The unit shall feature an 75 gallon pressured water tank of carbon steel construction. The tank will be removable installed on saddles rigidly welded to the hook lift frame. The saddle straps will we equipped with vibration proof rubber channels. The water tank will feature a flapper style lid assembly with replaceable gasket.  The tank will be equipped with a 3/4”  “Y” type strainer with removable screen assembly.  The water system will get pressurized air from the air brake system on the truck chassis. The air system will be equipped with a check valve to prevent reverse flow of air into chassis air brake system, air regulator, ASME pressure relief valve.  All fittings connecting the air pressure lines shall be  DOT approved fittings.  The water system will further be equipped with a valve and hose to direct water directly to the drum for slump control.  The until will also be equipped with a 25’ wash down hose with adjustable nozzle.  Note, chassis must be equipped with air brakes. If chassis is not equipped with air brakes select  “Zero Pressure Water System Option”.
Controls Electronic controls for speed and direction of drum, power discharge chute control and engine throttle control are located at  rear of the mixer in a waterproof  aluminum box. The controls shall feature MIL spec waterproof switches with vinyl boot covers. The electrical system shall be  equipped with a replaceable 30 amp fuse.
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 30,000 to 33,000 GVW chassis is recommended.

Estimate Payload Requirements:
Hook lift frame/Shortstop 3.5 Mixer 5,250 lb
75 gallons water 664 lb
3.5 Cubic yards concrete at 3,800#/yard 13,300 lb
Total 19,150 lb
General The standard Shortstop 3.5 mixer is operated with a closed loop hydraulic system, the hydraulic pump features a flow and direction control on the pump and the hydraulic pump’s sole purpose is to control the direction and speed of the mixer.    

It is possible to operate the drum in an open loop environment.  Open loop hydraulic systems are standard equipment on typical chassis driven PTO dump trucks, state dump/plow trucks and in general hydraulic systems found on most hook lift chassis.  Additional hydraulic control valves are required and field adjustment of the hydraulic equipment will be necessary at installation.  The open loop configuration is less efficient and controlling the speed and direction of the drum can be sluggish.  We strongly recommend the closed loop system when possible.  

Contact Ernest Industries to discuss your specific application.
Optional Equipment
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.
TRAINING 3.5 A factory direct technician shall be provided for a period of two working days to instruct the contractor/city personnel in the operation and maintenance of the mixer.  Strongly recommend if you do not have experience in the  operation of a concrete mixer.
OE3.5-1 Not applicable for hook lift configuration.
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 Not applicable for hook lift configuration.
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 Not applicable for hook lift configuration.
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’.