Land vehicles – Wheeled – Articulated vehicle
Reexamination Certificate
1999-09-02
2001-02-27
Johnson, Brian L. (Department: 3618)
Land vehicles
Wheeled
Articulated vehicle
C280S504000, C280S507000
Reexamination Certificate
active
06193260
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to hitch pin retainers that are used to prevent the unwanted removal or displacement of a hitch pin from a trailer hitch and tongue assembly when one vehicle tows another vehicle, for example, when a tractor tows a farm implement such as a trailer, plow, seeder, grading machine, or harvesting machine.
2. Background
A variety of attempts have been made to prevent the unwanted displacement and loss of the hitch pins that releasably connect a trailer hitch to a trailer tongue during towing operations where a vehicle such as a tractor pulls a trailer, machine, or iarm-type implement. Many of these attempts have failed to live up to expectations. This is most often because prior art devices require specialized hardware and or because the devices are not compatible for use with the most widely available types of hitch pins, trailer hitches, and trailer tongues. Also, the hitch pins are often lost or misplaced during non-use because when the pin falls out of the trailer hitch-tongue assembly during operation, it often drops to the ground in a field or a road where the pin is quickly hidden from view and lost. The prior art hitch pin retainer devices often fail to perform as intended either because the retainer device fails to retain the pin during operation or because the devices incorporate mechanisms that are so complicated to use that the operator elects to avoid employing the device to avoid the difficulty. Other types of retention devices are too costly to manufacture and purchase and are neither widely available nor used. Examples of prior art devices that are directed to devices that are expensive to manufacture, complicated to use, or that may not be compatible for use with the most widely available types hitch pins, trailers, and hitches include those disclosed in, for example, U.S. Pat. Nos. 3,825,284; 3,998,472; 4,415,175; 4,482,166; 4,526,396; 4,555,125; 4,666,177; 4,671,528; 5,199,733; and 5,779,277. U.S. Pat. No. 3,825,284 reflects an example of a device that is limited to a hitch pin that includes a safety retaining pin adapted to positively prevent removal of a hitch pin from a trailer tongue to, in turn, prevent inadvertent uncoupling of an implement and towing vehicle. However, the device requires the use of a specialized stud that must be formed in the trailer tongue and which may not be present on commonly used trailer hitch assemblies without special modifications. Similarly, U.S. Pat. No. 3,998,472 is restricted to a specially adapted trailer hitch that incorporates a spring-latch assembly adapted to retain a hitch pin in a trailer hitch. U.S. Pat. No. 4,415,175 is directed to a coupler latch mechanism that is expensive to manufacture in comparison to the preceding examples and that may be cost prohibitive to most operators who prefer a low-cost hitch pin to meet their trailer hitch coupling needs. U.S. Pat. Nos. 4,526,396 and 4,555,125 are both directed to customized hitch pin assemblies that incorporate a handle that is connected to a specialized hitch pin. The handles fold down over the hitch pin and surround and engage the entire coupled trailer hitch and tongue assembly in an attempt to prevent the inadvertent removal of the hitch pin. This type of hitch pin is has not found wide application because the cost exceeds the cost of the more commonly used hitch pins. Additionally, its use is restricted to those tractor-trailer coupling applications where the potential for interference of the typical hitch-tongue pivot mechanism would not pose a substantial problem during the operation of a tow vehicle when coupled to a trailer or towed implement. Experience with any of the preceding types of devices has shown that they are not immune from disconnection and decoupling of the trailer-hitch assembly when they are subjected to the severe vibration environment often encountered during operations of a tractor coupled to a trailer or other type of farm implement for towing.
What is needed is a cost-effective apparatus for retaining hitch pins to prevent unwanted displacement and or inadvertent removal from a trailer hitch and tongue assembly to thereby ensure that the assembly does not become decoupled during operation. Additionally, what is preferred but presently unavailable is a device that can be used as a hitch pin retainer that is compatible for use with the most widely available and presently used hitch pins and trailer hitch and tongue assemblies. The most preferred device should be comparable in cost to make, sell, and install as the most commonly available hitch pins presently known by and available to an operator for purchase in any of a wide array of wholesale and retail automotive, trucking, farming, and hardware supply outlets. The apparatus involved should be simple and straightforward in its design, installation, and use, and little effort should be required on the part of the manufacturer, parts supplier, and end-user to install, repair, and replace the device. Ideally, the hitch pin retainer assembly should incorporate a design that is compatible for use with the most readily available and widely used trailer hitch and tongue assemblies. Those assemblies include, for example, trailer hitches and tongues that are most widely used in farming operations where a simple hitch pin is employed for coupling a tractor and various trailers, machines, and farm-type implements.
SUMMARY OF THE INVENTION
The hitch pin retainer assembly of the present invention overcomes the many shortcomings of the prior art and efficiently prevents unintended displacement of a shear-type hitch pin assembly from a trailer hitch. The hitch pin retainer assembly includes a hitch plate assembly having a base plate formed with an aperture adapted to receive the shear pin assembly and having a retainer ledge. The hitch plate assembly is also formed with a latch plate that carries a latch assembly that incorporates a receptacle projecting from the latch plate that captures a spring or resilient member biased, slidable latch pin sized to extend, when in an extended position, to be disposed above and to retain and/or obstruct the shear hitch pin. The latch pin is also formed with a handle at one end. The hitch pin retainer assembly can be either bolted or welded to an existing trailer hitch and also includes a tether that can be attached to the shear pin to prevent accidental loss.
The present invention is directed to a hitch pin retainer assembly that includes a shear pin assembly that is formed with a head portion opposite a tapered end. The retainer assembly also includes a hitch plate assembly that has a base plate formed with an aperture adapted to receive the shear pin assembly and that has a retainer ledge. A latch plate is carried from the base plate and is formed with a latch pin hole. Also included is a retainer latch assembly that incorporates a receptacle that is substantially centered about the latch pin hole. The latch assembly projects from the latch plate and is formed with an interior recess having an open end adapted to receive a latch pin slidable between a retracted and an extended position. The latch pin is sized to extend, when in the extended position, through the recess to be disposed within latch cage. The latch pin is formed with an engagement end having a retainer pin configured to releasably engage the retainer ledge when the pin is in the retracted position, and an opposite end having a handle. A medial portion of the latch pin is formed between the engagement end and opposite end and includes a spring or resilient member seat pin. The retainer latch assembly also includes a receptacle cap attached to the open end of the receptacle to capture a metal extension spring, or compressible resilient member made from an elastic polymer such as rubber, received about the medial portion and within the recess. The captive spring or resilient member is operative to bias the latch pin towards the extended position to retain the shear hitch pin. In operation, the base plate is ada
Homan Todd B.
Stammen Ronald L.
Casey Sean M.
Draper Deanna
Johnson Brian L.
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