Schaeff Incorporated

Other

Schaeff, Incorporation

Isaac Avitan

Robert C Weihe

Lev M Bolotin

Eugene A Helmetsie

A processor implemented stabilization system for load handling equipment monitors at least a portion of the equipment weight load at an equipment support member. Reduction below or increase above predetermined values signals an approaching tip over condition and triggers alarm condition responses for stabilization of the equipment. In a counterbalanced lift truck, the equipment weight load on a rear steer wheel is carried by an outer bearing race of a spindle and is transferred from the race to a load cell which is positioned between the race and a shoulder of a mounting tube. The load cell output is received at a processor which monitors the cell to determine if there is an approaching longitudinal tip over condition (toward or away from the load) as well as a lateral tip over condition. Upon sensing an approaching tip over condition, the processor implements one or more corrective measures such as actuation of an annunciator, preventing an increase in vehicle speed, preventing elevation of the load, preventing mast tilt, etc.

Load sensing system

Stabilization system for load handling equipment

Hydraulic hose lines between an inner rail and an adjacent outer rail of a lift truck mast are reeved within a hollow chain guideway. Opposite ends of the chain are fixed to vertical channels; one channel is mounted to the outer rail and the other, to a center support of the inner rail, with the lowermost portion of the chain looped between the channels. The distance between the chain portions seated in each channel provides an unobstructed operator viewing window. Elevating the inner rail causes the chain to progressively separate from the outer rail channel and engage the inner rail channel while lowering of the inner rail causes the chain to separate from the inner rail channel and engage the outer rail channel.

Lift truck mast hose reeving system with chain guideway

Motor Drive

A dual axis carriage assembly for industrial control handles includes a base yoke fixed to a support surface and a moveable yoke to which the control handle is attached. Each yoke includes a pair of coaxial spaced bearing surfaces and journal portions of one shaft of a cross shaft assembly are received in the bearing surfaces of the moveable yoke while journal portions of the other shaft are received in the bearing surfaces of the base yoke. A torsion coil spring is carried on each shaft with the spring having a pair of parallel arms which straddle the sides of a flange projecting from the yoke within which the corresponding shaft is received. A dog, fixed to the end of each shaft includes an axial leg which is positioned between the spring arms. Rotation of each shaft relative to its yoke results in displacement of one spring arm so that the spring returns the shaft to a null position. The dog also includes two radial legs which engage the yoke flange to provide rotation limit stops. An angular displacement transducer and includes a body fixed to each yoke and a stem which is received in an axial bore of the corresponding shaft to generate a signal representative of angular displacement of each shaft with respect to a reference position.

Dual axis carriage assembly for a control handle

Fork lift truck

A system for controlling a separately excited dc motor, where control is achieved through a microprocessor-based independent PWM control of a chopper (armature) and an H-bridge (field), and where mechanical speed sensors are not used. Connected to the armature is an armature voltage amplifier for varying the applied armature voltage. A field current amplifier is also provided for determining the direction of motor rotation and varying the voltage applied to the field winding. A decoupling controller adjusts the armature voltage and the field current.

Speed regulation of DC motor using current sensing means

A drive train assembly for motorized vehicles, for example lift trucks. The rotational movement of the output shaft of a motor, for example an electrical motor, is transmitted to a drive wheel by a single drive shaft having at one end a gear interface assembly consisting of a gear on the end of the output shaft and a gear on an end of the drive shaft, and at the other end of the drive shaft by a second gear interface assembly consisting of a gear on the drive shaft and a gear fixedly mounted on the inside of the rim of the drive wheel. The drive train assembly allows for strong, reliable transfer of rotational torque to the drive wheel in a compact, non-complex arrangement with a minimum number of drive parts, bearings and gears. The drive wheel is independently rotatably supported on a spindle mounted to the chassis of the vehicle and bears a majority of the external load and stresses, relieving the drive train assembly of a substantial amount of such load and stresses. The assembly contributes to other important lift truck design considerations, such as mast placement, counterbalance requirements, and right angle stack.

Drive train assembly

A turning control system for an electric vehicle includes a differential filter which receives a signal indicative of a desired vehicle steer angle and generates a pair of signals representative of proportional speed and direction at a left and a right drive wheel of the vehicle. Speed limit factors generated by an angular speed limit filter and an operator set throttle control are applied to the signals indicative of proportional speeds to generate desired proportional speed signals. The desired proportional speed signals are applied to a motor coupling controller along with signals indicating the actual motor speeds. Error signals representative of the difference between the desired speed and the actual speed of each motor are scaled and integrated to generate lag signals (representative of accumulated error) and the lag signal of one motor is applied to the desired proportional speed signal of the other motor to generate coupled control signals which are applied to respective left and right motor control circuits.

Coupled differential turning control system for electric vehicle

A method for handling conventional stacks of baked goods trays for the baking industry. A platen is moved underneath side-by-side stacks of trays. The platen supports the underside of the stacks of trays and prevents lateral movement of the bottom of the stacks by guiding the platen into channels that exist in the bottom of the trays. The platen is attached to an upright which is tiltable and which extends along one side of the baked goods trays when on the platen to support the stacks along their vertical height. Tilting of the upright causes the platen to lift and the trays to tilt against the upright where they are supported underneath and along the side and thus can be moved and handled. By utilizing the split platen and the tall tiltable upright with a motorized vehicle, an economical and efficient method of handing baked goods tray stacks is possible, eliminating significant manual labor and risk of worker injury.

Method of handling stacks of baked goods trays

A regulation system for controlling a dc motor having a separately excited armature and field includes microprocessor based pulse width (duty cycle) and frequency modulation control of an armature amplifier and a field amplifier. Motor operating efficiency is optimized through microprocessor control of the field amplifier as a function of actual armature current, actual field current and desired armature speed. Sensed armature current is multiplied by a fixed optimal field constant to generate an optimal field current control signal. The optimal field current control signal is summed with a signal representative of field current required for desired armature speed less a signal representative of actual field current to generate a field current error signal. A controller receives the field current error signal and generates a pulse width modulated field current control effort signal which is applied to the field amplifier. An armature voltage controller receives an input signal which is the difference between desired armature speed and actual armature speed. The input signal is generated only when actual field current exceeds a predetermined field saturation current value. The controller generates a pulse width modulated armature control effort signal which is applied to the armature amplifier only if actual armature current is below the maximum allowable armature current.

Regulation system for decoupled efficiency optimized operation of DC

Control handle for a material handling vehicle

Material handling vehicle operator display

The invention features a system for controlling separately excited shunt-wound dc motors, where control is achieved through microprocessor-based independent PWM control of a chopper (armature) and an H-bridge (field). Connected to the armature is an armature voltage amplifier for varying the applied armature voltage. A field voltage amplifier is also provided for determining the direction of motor rotation and varying the voltage applied to the field winding. A first sensor is connected to the wheel of the vehicle in which the motor resides in order to determine the wheel speed. A second sensor is connected to the armature circuit in order to determine the armature current. A third sensor is connected to the field circuit in order to determine the field current. A decoupling controller uses the wheel speed and armature current information, and adjusts the armature voltage and the field voltage. An optimal controller uses the wheel speed, field current and armature current information, and adjusts the armature voltage and the field voltage.

Speed-dependent traction motor controller for vehicles

The present invention features a system for optimizing control of separately excited shunt-wound dc motors, where optimization is achieved through microprocessor-based independent PWM control of a chopper (armature) and an H-bridge (field). Connected to the armature is an armature voltage amplifier for varying the applied armature voltage. A field voltage amplifier is also provided for determining the direction of motor rotation and varying the voltage applied to the field winding. A first sensor is connected to the driven wheel(s) of the vehicle in order to determine the wheel rotational speed. A second sensor is connected to the armature circuit in order to determine the armature current. A third sensor is connected to the field circuit in order to determine the field current. A decoupling controller uses the wheel speed and armature current information, and adjusts the armature voltage and the field voltage. An optimal controller uses the wheel speed, field current and armature current information, and adjusts the armature voltage and the field current.

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Sioux City, IA, United States of America

Isaac Avitan