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US 4,231,443 AGranted
Overload couplings
OwnerCornelis van der Lelyinventor
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OwnerCornelis van der Lelyinventor
Estimating the term…
A tractor driving system includes an overload coupling in which at least one latch plunger housed in one coupling part fits in a recess of a second part to establish connection. The plunger has or is part of a hydraulic system and can be forced out of the recess upon overload against the hydraulic pressure in the system and, in some instances, with the aid of centrifugal forces if the coupling is rotary. The plunger can be part of a unit that can be releaseably fastened in the coupling housing and set to trip upon torque exceeding a predetermined level on the coupling. Also, the plunger can have internal ducts or external conduits that include a pressure relief valve, as well as a spring return, which can effect connection upon reduced speed when centrifugal force factors are reduced. The pressure in the system can be set remotely with a piston that is spring loaded. In one variation, the coupling can be within a planetary gear system that establishes driving connection from an input to an output via planetary and sun gears. Thus, the planetary gears can be mounted on a carrier that can be held to the housing by a plunger to drive a p.t.o. shaft. Two sets of planetary gears can be mounted within the gear housing to drive the p.t.o. shaft at different speeds and a common plunger used to establish either connection. As part of the system, a distributor can selectively engage either system and a switching member set to allow fluid to pressure the system to a predetermined level.
A tractor comprising driving means including a power takeoff shaft that has a coupling connectable to a driven shaft member, said coupling having two relatively moveable parts that are normally connected by locking means, said locking means comprising at least one displaceable latch in a closed hydraulic system and said latch being displaced upon overload to allow relative movement between said parts, said system including a closed space for hydraulic fluid and said latch having a part that normally divides said space into two portions, duct means in said latch part that communicates hydraulic fluid from one portion to the other upon overload, the volume of the space remaining substantially unchanged and the latch being displaced against the pressure in said system upon overload.
A tractor comprising driving means including a power take off shaft that has a coupling connectable to a driven shaft member, said coupling having two relatively moveable parts that are normally connected by locking means, said locking means comprising at least one displaceable latch in a closed hydraulic system and said latch being displaced upon overload to allow relative movement between said parts, said system including a closed space for hydraulic fluid and said latch having a part that normally divides said space into two portions, duct means in said latch part that communicates hydraulic fluid from one portion to the other upon overload, said latch part being slideably mounted within holder means on a rotatable driving shaft member and displaceable in a generally radial direction relative to the axis of rotation of that member, said latch part being displaced outwardly against the pressure in said space and the volume in said space remaining substantially unchanged.
A tractor comprising driving means including a power takeoff shaft that has a coupling connectable to a driven shaft member, said coupling having two relatively moveable parts that are normally connected by locking means, said locking means including a displaceable latch in a hydraulic system and said latch being displaced against hydraulic pressure upon overload to allow relative movement between said parts, a relief valve in said system that establishes the pressure tolerance before overload and latch displacement, said valve being adjustable to vary the pressure tolerance and setting means adjusting said valve from a remote driver's seat.
A tractor comprising driving means including a power takeoff shaft that has a coupling connectable to a driven shaft member, said coupling having two relatively moveable parts that are normally connected by locking means, said locking means including at least one displaceable latch in a hydraulic system and said latch being displaced against hydraulic pressure upon overload to allow relative movement between said parts, said system including a setting device which comprises a spring-loaded piston, said piston normally pressuring hydraulic fluid and the latch into engagement with a recess to establish or re-establish connection.
A tractor comprising driving means including a power takeoff shaft that has a coupling connectable to a driven shaft member, said coupling having two relatively moveable parts that are normally connected by locking means, said locking means including at least one displaceable latch in a hydraulic system and said latch being displaced against hydraulic pressure upon overload to allow relative movement between said parts, the said coupling being contained in gear box means and at least one gear wheel of a gear transmission for the power take-off shaft being engaged by said latch to establish operative connection of the parts, said power take-off shaft being connectable with a first or a second pinion of said transmission through said one gear in order to obtain different speeds of the power take-off shaft.
Dependencies are inferred from the claim text.