Access Modules- This exclusive Crown system acts as the interface between the operator or technician, and the truck electronics system. It allows the truck to have its performance parameters set through the dash display, as well as to display trouble codes. Other manufactures have similar devises but Crown is the only one to use "Access Modules".
- Backing plate- A circular metal plate that attaches to the drive motor and serves as the attaching point for all of the brake hardware.
- Electric disc brake- An electrically actuated braking system used in place of a hydraulically actuated brake system. The brake is mounted on the drive motor and a sensor under the brake pedal sends a signal to the brake assembly to apply the brake based on pedal position.
- Master cylinder- A hydraulic device that converts mechanical force into hydraulic force which then actuates the wheel cylinder or caliper pistons to apply the brakes.
- Shoe and lining (brake shoes)- An assembly that consists of a stamped steel plate with a composite friction material bonded to it. The pressure from the wheel cylinder forces the brake shoes to spread apart. The force of the bonded material against the brake drum slows the rotation of the drive motor and stops the machine.
- Wheel cylinder or Slave cylinder- A hydraulic cylinder in a drum brake system that transfers the hydraulic force from the master cylinder to the brake shoes through two small pistons in the cylinder.
- Capacitor- An electronic energy storage cell that may be used to maintain steady voltage in an electronic circuit. The capacitor may also act as a filter in the circuit as it can "differentiate" between frequencies.
- Chopper- A motor control device that "chops" up available battery power to regulate motor speed.
- Contactor panel- A flat metal panel on which the contactors are mounted. It is typically comprised of the mounting plate, contactors, electric bus bars, power cables and wiring harnesses.
- Contactors- An electronic switch that uses low amperage control to turn on or off a high amperage load. An electromagnetic coil in the contactor is energized when a specific function- such as direction or hydraulics- is selected. The coil then moves a contact tip or set of tips to open (turn off) or close (turn on) the electric circuit to the specific motor that the contactor controls.
- Control panel- Commonly referred to as the Traction Panel this is a flat metal panel on which the drive control devices are mounted
- Current sensor/ shunt- On SCR control panels this device is typically a strip of metal that has a known resistance. As the current of the circuit flows through this strip the voltage drop from one end of the strip to the other is measured and the current flow is then calculated.
- Hydraulic panel- A flat metal panel on which the hydraulic system control devices are mounted.
- Oscillator card- A printed circuit board that controls the functions of the electronic circuits on SCR controlled trucks.
- PMC control- Programmable Motor Controller is the trade name for a solid-state control box manufactured by Curtis Instruments that controls the operating functions of a specific motor. These units can be programmed to operate the motor under very precise parameters by the use of a hand-held programmer .
- Potentiometer- A variable resistor that is used to control the amount of voltage allowed through an electrical circuit. It is commonly used to control motor speed.
- Rectifier- A solid state semiconductor that behaves like a one-way valve in an electronic circuit. The rectifier allows current to flow in only one direction while blocking current in the opposite direction.
- Resistor control- An electronic control system that uses series of resistors to control motor speeds.
- SCR- A solid-state semiconductor that acts like a switch when it receives an electronic pulse and continues to conduct as long as it remains energized.
- SCR control- An electronic control system that uses Silicon Controlled Rectifiers and a control card to control motor speeds.
- Snubber- A device that controls and filters electrical peaks across a rectifier protecting the circuit.
- Thyristor- See SCR
- Traction panel- A flat metal panel on which the drive motor control devices are mounted. Commonly associated components such as drive motor controllers, bus bars, power cables and wiring harnesses are found on the traction panel assembly.
Control Handle and Steering Arm-
(houses the controls for the steering and direction of the truck.)
- Brake Rod- An adjustable rod used to mechanically apply the brake system whenever the control handle is in the full up or full down position.
- Brake switch- A microswitch located at the bottom of the control handle that interrupts the power circuit to the drive motor when the handle is in the full up or full down position and the brake is applied.
- Control head/pod- The assembly at the top of the control handle that houses the directional control and lift/lower switches. The hand grips on the control head are used to turn the drive/steer unit and change the direction and speed of the truck.
- Grab bar- Used on rider Class Ill trucks the grab bar is located behind the operator platform and contains the switches used to control the direction and lift of the truck while the control handle is used to steer and control speed.
- Handle return spring/ gas shock- The device that brings the steering control handle back into the upright position when the handle is released. This action also disrupts power to the drive motor and activates the braking system.
- Handle weldment- The metal arm that is between the control head/pod and the steer unit.
- Reverse (belly button) switch- A safety switch- usually red in color- that is at the end of the control handle. This switch automatically reverses the direction of the unit whenever it is pressed to keep the operator from being crushed if he or she is between the handle and a stationary object.
Drive Unit- This assembly acts as the transmission and steering unit for Class Ill trucks. The drive motor mounts to the upper section of the drive unit and transfers power from the motor to the drive tire through a series of reduction gears. The entire drive motor/ drive unit assembly is mounted to the truck chassis on a very large bearing set so that the assembly can turn and steer the truck.
(This is the actual chassis of the truck. It serves as the attaching point for the lift linkage, outriggers and the drive/steer unit.)
- Caster assembly- This is an adjustable swivel wheel that is mounted on one or both sides of the drive unit to stabilize the truck. This is commonly used on walkie/rider trucks.
- Fork- The structure that supports the load. On walkie pallet trucks these are part of the frame and support the lift linkage and load wheels; on walkie stackers these are forged steel fork similar to standard forklift trucks.
- Fork/ Wheel riser- A machined casting part of the lift linkage that supports the load wheel at the end of the forks on walkie pallet trucks. This riser lifts up the forks in conjunction with the lift cylinder to raise the load for transport by means of mechanical linkage.
- Load wheels- A nylon, polyurethane or steel wheel with bearings that is attached to the riser or outrigger by means of an axle. This wheel supports the weight of the load and allows the truck to roll.
- Outriggers- The front legs on the walkie stacker truck onto which the load wheels are mounted. The outriggers are either welded to the frame or adjustable by bolts and straddle the load. They serve to keep the lift balanced so it does not tip forward under load.
- Pallet entry rollers- Small plastic rollers that are mounted to the underside of the fork on walkie pallet trucks to aid in easing the forks into the pallet so the forks don't hang up.
- Pull rod- On walkie pallet trucks this is a long piece of flat bar stock or tubular rod that links the torque tube at the lift cylinder end of the truck to the wheel riser at the fork end of the truck. It transfers the lift force to the load wheels to make the fork platform rise evenly.
- Skid- A piece of nylon or high density polyethylene that is used in place of caster wheels on walkie pallet trucks to keep the truck from tipping over during turns or on uneven surfaces.
- Torque tube- A metal tube with arms welded to it that mounts at the lift cylinder end of a walkie pallet truck . This tube rotates as the lift cylinder rises up and down and transfers this rotational torque to a lateral pulling or pushing force. The pull rod is attached to the torque tube and pushes or pulls on the wheel riser to make the forks rise.
- Armature- The rotating part of an electric motor. This part is also referred to as a rotor.
- Commutator- A set of insulated copper contact segments positioned around the armature shaft and connected to the armature coils. The motor brushes transfer the truck battery voltage through the commutator and the armature coils to make the motor turn.
- Brushes- Spring loaded carbon blocks that conduct current between the stationary power wires and the rotating commutator.
- Brush holder- A non-conductive plate, or ring, that holds the carbon brushes in a fixed position above the commutator.
- Drive motor- The large electric motor that is connected to the drive unit to propel the lift truck.
- Hydraulic pump motor- The electric motor that drives, or turns, the hydraulic pump. Sometimes also referred to as the lift pump motor.