Joints and connections – Articulated members – Pivoted
Reexamination Certificate
1999-04-21
2001-11-27
Browne, Lynne H. (Department: 3629)
Joints and connections
Articulated members
Pivoted
C403S370000, C403S154000
Reexamination Certificate
active
06322280
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to pin joints for pivotal connection of work tools to linkages and the like, and more particularly, to a collet type pin joint to provide desired strength and stiffness properties, and which is oil filled to provide long intervals between lubrication requirements.
BACKGROUND ART
Currently, joints used for the pivotal connection of buckets and other work tools to lift arms and other linkages of work machines commonly include collet type joints and flag type joints. Both types of pin joints utilize a sleeve type bearing mounted in a first member, usually the lift arm or other link, and a pin or pin assembly attached to a second member, which is typically the bucket or other work tool. Collet pin joints include tapered collets which are pressed in or frictionally engaged with the second member for securing the pin or pin assembly in position. This makes the collet pin joints the stronger and stiffer of the two types of joints. However, because of the press or frictional fit, it is difficult to control the axial relationship between the collets and the bearing, necessitating the use of seals therebetween which are not sensitive to axial loading. To meet this need, the known collet pin joints are grease lubricated to allow grease seals to be used. But, this requires frequent greasing to avoid seizing, galling and/or breakage. As another limitation, the known collet pin joints use a pin assembly typically provided as a weldment or cartridge, which is not intended for replacement in the field. Flag type pin joints differ from collet pin joints in the use of one or more external members known as flags for retaining the pin or pin assembly within the bearing. This provides consistent axial length control such that oil seals can be used and oil as the lubricant, thus providing the advantage of requiring less frequent lubrication. The pins or pin assemblies of the flag type joints are also easy to remove and replace in the field. However, the flags have been found to be more prone to wear and breakage, resulting in higher than desired incidence of repair.
Thus, what is required is a pin joint that provides the strength and stiffness of a collet pin joint, but the axial length control and long intervals between lubrication and ease of serviceability of the flag type joints.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.
DISCLOSURE OF THE INVENTION
In one aspect of the present invention, an oil sealed collet pin joint or assembly for pivotally connecting a first member of a work implement assembly to a second member thereof, is disclosed. The first member includes an annular bearing having an inner circumferential bearing surface defining a bore having an axis therethrough, a first axial end face at one end of the bore, and a second axial end face at an opposite end thereof. The second member includes first and second brackets or other structural elements defining a space therebetween, each of the brackets having an inner side wall defining an aperture therethrough, the first member being positionable in the space with the bore between the apertures. The present pin joint or assembly includes a pin having opposite stepped axial ends and an outer surface extending therebetween, the pin being adapted to be supported for pivotal or rotational movement in the bore of the first member with the opposite stepped axial ends in predetermined axially spaced relation to the respective axial end faces of the bearing. The present joint or assembly includes a pair of annular retainers, the retainers being adapted to be positioned in the apertures of the brackets and having inner circumferential stepped surfaces defining cavities adapted for cooperatively receiving and engaging the stepped axial ends of the pin, respectively, for positioning the retainers and the pin in predetermined axial relation to the bearing to provide length control. The present joint or assembly further includes a pair of collets adapted to be wedged in the apertures of the brackets between the inner side walls and the retainers, respectively, for holding the retainers and the pin in the predetermined axial relation to the bearing.
According to a preferred aspect of the invention, the present pin joint or assembly is oil filled, including seal members disposed between the retainer members and the axial end faces of the bearing forming sealed conditions therebetween, respectively, and seal members forming sealed conditions between the stepped axial ends of the pin and the retainer members, defining a cavity adapted for receiving the oil between the inner circumferential bearing surface and the outer surface of the pin. The fixed axial relation of the retainer members and the pin to the bearing enables controlling axial loading of the seal members for long life thereof, and the pin assembly can be easily disassembled and reassembled in the field for service, when required.
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Browne Lynne H.
Caterpillar Inc.
Haverstock Garrett & Roberts
Malcolm Tomlyne
Meyers Liza J.
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