An improved truck for tow line use is provided with a brake system designed to stop the truck in response to engagement of a front bumper against an obstacle, while minimizing the force applied by the truck and bumper to the obstacle. The truck includes a brake member having a bottom floor-engageable surface and an upper wheel-engageable surface. A longitudinally movable brake support member on the truck supports the brake member in front of at least one wheel for relative movement between a retracted position ahead of the wheel and a braking position in which the brake member is engaged beneath the wheel. The brake support member is mounted on the truck by low-friction ball or roller bearings, to further insure operation of the brake system with minimal application of force against an obstacle. The front bumper is movably mounted on the brake support member for movement from a rest position to an active control position by engagement with the obstacle. Movement of the front bumper to active position controls an anti-back-up device, in the form of a one-way clutch and brake interconnecting the truck body and brake support member, which permits forward movement of the truck body and wheel onto the brake member with a resulting cessation of forward motion due to the action of the brake member and weight of the truck, rather than the resistance of the obstacle. The anti-back-up device also prevents premature rearward movement of the wheel and truck body from the brake support member. The anti-back-up device is released forcibly by return movement of the front bumper to its rest position. Improved tow pin lifting and rear bumper features are also shown, including a specially latched, resiliently held bumper.
A tow cart is provided with an arrangement in which the tow or drive pin is adapted to be moved out of engagement with the conveyor drive, in response to a predetermined degree of obstruction to the tow cart, by a spring-loaded overcenter double toggle movable from a cocked to a released position in response to the obstruction, and in which the drive pin is pivotally supported so that it may swing forwardly away from the conveyor drive upon the release. In the cocked position of the toggle mechanism the mechanism restrains the forward pivotal movement of the drive pin.
A conveying system includes a movable conveyor track with a plurality of load carrying units movable with the conveyor track for conveying workpieces along the path defined by the conveyor track. Each of the load carrying units includes a device to selectively couple and uncouple the load carrying units from the conveyor track so that the load carrying units can selectively and individually be coupled to the conveyor track for movement therewith. In one embodiment, the system includes accumulation areas at preselected locations along with counting and calculating systems to determine and control the number of load carrying units between accumulation areas. In a second embodiment, means are provided to release load carrying units at preselected time intervals from each accumulation area.
Systems and methods are provided for securing a pin within a raised display system. A washer surrounds the pin. A washer recess comprises a contact surface configured as to bring the washer into a tilted position relative to the pin, such that the washer is brought into physical communication with the pin. A reset mechanism moves at least a portion of the washer to force the washer into a position substantially level relative to the pin, such that the pin can move freely through the washer. An electromagnet holds the washer in the substantially level position when the electromagnet is activated.
