Braking apparatus and method for storage and retrieval vehicles

Actuator apparatus for sensing overspeed descent, along a guide rail or mast, of a vertically travelling carriage of a storage and retrieval vehicle and for activating at least one braking means, said actuator comprising:

• at least one friction wheel means whereby linear travel of the carriage along the guide rail or mast is translated to a rotational rate;
• A tach/generator means directly coupled to the at least one friction wheel means whereby the rotational rate of the friction wheel means drives the tach/generator means;
• electrical circuit means receiving output from the tach/generator means for detecting overspeed descent of the carriage and for providing an electrical current output only when an overspeed descent is detected;
• and
• at least one electrical solenoid means, each solenoid means comprising means for contiguously interconnecting to a braking cam of the at least one braking means and for receiving and being actuated by the electrical current output to directly reposition the braking cam to activate the at least one braking means.

Actuator and braking apparatus for sensing overspeed descent, along a guide rail or mast, of a vertically travelling carriage of a storage and retrieval vehicle, and for actuating at least two cam braking devices, said actuator and braking apparatus comprising:

• at least two mechanically independent cam braking devices shaped such that braking forces are increased upon descent and operatively affixed to the carriage;
• wheel means whereby linear travel of the carriage along the guide rail or mast is translated to a rotational rate;
• a tach/generator means directly coupled to the wheel means whereby the rotational rate of the wheel means drives the tach/generator means;
• electrical circuit means receiving a voltage signal output from the tach/generator means for detection of overspeed descent of the carriage and for providing an electrical current signal output to the at least two mechanically independent cam braking devices;
• electrical cable means which delivers the electrical signal output from the electrical circuit means to the at least two electrically activated cam braking devices.

Actuator and braking apparatus for sensing overspeed rate of descent of a dual most storage and retrieval vehicle carriage when traveling along at least two guide rails or masts and for actuating at least one braking device when overspeed rate of descent occurs, said apparatus comprising:

• at least one braking device attached to the carriage and disposed at one of the at least two guide rails or masts;
• electrical actuator apparatus disposed at one of the at least two guide rails or masts, said electrical actuator apparatus comprising:
• at least one wheel means biased to rotatably measure relative rate of travel of at least one wheel against the relatively static guide rail;
• tach/generator means directly coupled to at least one wheel and which generate an electrical signal which is a function of the rate of travel of the carriage and rotation of the at least one wheel;
• electrical circuit and communication means whereby, when an overspeed condition is interpreted, an actuating signal is sent to the at least one braking device;
• said at least one braking device comprising braking cam means which comprise a guide rail engaging braking cam and pivotally attached braking cam rotating solenoid means which are activated by a current only received from the electrical circuit and communication means when an overspeed condition is interpreted and to directly rotate said braking cam into braking engagement with the guide rail or mast.

A method for activating a brake on a carriage of a storage and retrieval vehicle comprising the steps of:

• providing a solenoid directly and contiguously interconnected to a braking cam;
• electrically sensing a rate of travel of said carriage and generating an electrical current thereby;
• transmitting at least a portion of the current to the solenoid only when said rate of travel exceeds a predetermined speed and direction, said current portion being adequate to activate the solenoid;
• activating the solenoid and thereby directly rotating the contiguously interconnected braking cam into braking orientation;
• and
• engaging said cam against a relatively static vertical mast member such that braking forces are increased due to a camming action of said cam upon descent to thereby brake the carriage.

A method for activating a brake on a carriage of a storage and retrieval vehicle comprising the steps of:

• electrically sensing a rate of travel of said carriage and generating an electrical current thereby;
• transmitting at least a portion of the current to a solenoid only when said rate of travel exceeds a predetermined speed and direction, said current portion being adequate to activate the solenoid;
• activating the solenoid and thereby directly rotating a braking cam into braking orientation;
• engaging said cam against a relatively static vertical mast member such that braking forces are increased due to a camming action of said cam upon descent to thereby brake the carriage;
• and
• while in a non-braking condition, maintaining said braking cam within a predetermined critical distance of said mast by spring forced camrol guidance bearing means.