Joints and connections – Articulated members – Including static joint
Reexamination Certificate
2000-06-29
2003-04-29
Browne, Lynne H. (Department: 3679)
Joints and connections
Articulated members
Including static joint
C403S164000, C403S322200, C403S165000
Reexamination Certificate
active
06554524
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to improvements in connectors for towing cable or conduit or the like, i.e., for stringing cables from pole to pole, hauling cable through underground conduits, and more particularly to swivel connectors for use with power and telephone cable, and especially to “disconnect” swivels whose components separate under excess loading to preserve the cable especially for use with fibre optic cable and for hauling conduit for cable through underground bore holes.
BACKGROUND OF THE INVENTION
The swivel connector disclosed in U.S. Pat. No. 2,387,599 uses ball bearings travelling in a race defined by or secured to opposed male and female components to interconnect and support same for rotation in relation to each other which male and female components thereof are to be connected to a hauling line and a cable respectively.
Such swivel connector cannot be taken safely around a pulley or bullwheel under load.
The swivel connectors revealed by U.S. Pat. Nos. 5,494,367 and 5,529,421 provide in one embodiment a first swivel head which is attached to a swivel shaft secured within a hollow body by a locking nut which in turn is connected to a second swivel head. Tapered roller bearings support the swivel shaft for rotation in one setting and transmit tensile loading from the shaft to the hollow body.
A series of restrictive seals serve to block the passage of debris from the outside to the interior.
In another embodiment the first and second swivel heads are attached to an opposed pair of swivel shafts and likewise are provided with restrictive seals with the object of utilizing the capability of one swivel head should the other fail.
The swivel connectors of U.S. Pat. Nos. 5,594,367 and 5,529,421 cannot, under load, be safely taken around a pulley or bullwheel.
The breakaway swivel connector disclosed in U.S. Pat. No. 4,678,365 has a centre pin from which material has been removed centrally internally thereof to create a shear factor so as to limit the load applied to the cable in installing same on poles or in underground ducts.
The breakaway connector of U.S. Pat. No. 5,122,007 uses assorted mechanical pin-type breakaways to protect the cable from damage in similar circumstances.
Both aforementioned breakaway connectors require replacement parts to be reinstalled after each cable pull has been completed and the sheared pin parts removed.
Each of the latter breakaway type connectors may require as many as twenty five (25) differently calibrated pins, preferably colour coded for identification of the breaking tension for installation either in the work place or in the field of operation. Such an arrangement, however, gives rise to human error in the selection of the requisite pin for the particular pull.
The breakaway components of the aforementioned U.S. Pat. Nos. 4,687,365 and 5,122,007 have been designed to separate at plus or minus ten (10) percent of their rated break load. Those limits, however, are not always precise or finite in that machine shop operations and the mechanical functions performed are also subject to human error leading to possible failure of the cable pull.
Moreover, the latter mentioned swivel connectors likewise are not designed to be safely taken around pulleys or bullwheels under load.
Further, the swivel connectors of all aforementioned U.S. patents operate safely only if loaded in one direction. Hence if incorrectly connected by attaching the wrong end to the cable to be pulled the swivel will fail and the cable pull aborted.
Other downside aspects inherent in the aforementioned breakaway connectors are the necessary disassembly to replace the break pins and then reassembly. Those steps can prove to be very costly in a field situation because of down time, because of potential loss of parts and the increased labour costs for disassembling and reassembling.
OBJECTS OF THE INVENTION
One principal object of this invention is to provide an improved swivel connector which can be loaded in either direction, that is, the swivel connector serves its purpose either way; and will operate whether the pull exerted is applied through the hauling line or through the cable itself.
Such swivel connector can include a separation or “disconnect” structure for limiting the pulling load.
Another principal object is to provide a swivel connector that can be taken safely around a pulley or bullwheel under load.
Still another principal object of this invention is to provide an improved separation or “disconnect” structure for a connector of the category under consideration which compared to known structures greatly minimizes the likelihood of damage to power and telephone cable and particularly to fibre optic cable during a cable pull whether overhead from pole to pole or underground in PVC ducts or conduits, in vaults or otherwise and to conduit hauled through underground bore holes.
Still another object is to provide an improved “disconnect” connector which is fully reusable in a subsequent cable pull without any dismantling or disassembly of the components thereof or the replacement of parts in the reassembly of same, whereby human error in selection of replacement parts and reinstallation is entirely eliminated.
Another object of this invention is to provide an improved swivel connector that can be more easily utilized in confined spaces such as in riser ducts in high rise buildings, and follow a shorter bend radius as compared to known swivel connectors particularly when used in underground PVC ducts with its sweeps and bends.
It is also a specific object to provide an improved swivel connector of the type in which the separation or “disconnect” tension characteristics have a substantially increased range of from about 100 psi to 5,000 psi and beyond if so desired.
Other important objects are to provide connectors including swivel connectors for the uses outlined which require low maintenance, are economically manufactured, do not require special tools in maintaining operability and have an extended operating life by virtue of the improved structure of same.
Features of the Invention
One feature of this invention resides in providing selected bearings for a swivel connector structure in which the swivel shaft is supported by and rotates within a bearing combination, in one embodiment, of a three (3)-piece dual thrust needle bearing at one end and by a flanged Permaglide™ bearing at the other end and in another embodiment the combination of Permaglide™ washer bearing and three (3)-piece needle dual thrust bearing at one end and a roller bearing at the other end.
Both embodiments are suitably sealed preferably by a Buna-N-O ring against ingress of debris and to contain lubricant which bearing combinations and seal confer upon the preferred embodiments the capability to be pulled safely under load in either direction; and further by reason of such combination of bearings the longitudinal dimension of connectors can be reduced, greatly facilitating travel through circuitous passageways and also around sheaves, pulleys or bullwheels.
Another feature of this invention resides in providing an interconnection between opposed surfaces of mating male and female components of a connector in the form of a selection of a spring loaded resilient steel ball mounted within an elongated passageway in either mating component to seat lowermost against an annular lip so shaped as to project a portion of the resilient steel ball beyond the opposed surface thereof and into a circumferentially extending matching recess or groove formation presented by the opposed surface of the other mating component, which spring loading of the steel ball can be so calibrated as to be forced from such groove formation and out of its seat into the elongated passageway only when the tensile loading applied to the mating components exceeds the spring loading applied to the resilient steel ball.
As a consequence of that arrangement the swivel components will separate or “disconnect” before the cable ruptures or is otherwise damaged.
When separation occurs no parts are destroyed.
Browne Lynne H.
Garcia Ernesto
Green Weldon F
Veneta Industries INC
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