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Description  |
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BACKGROUND OF THE INVENTION
This invention relates generally to the field of telephony, and more
particularly to an improved main distributing frame used in telephone
offices for the interconnection of individual cable pairs to switching
equipment. Main distributing frames of this general type are well known in
the art, and the invention lies in specific constructional details which
simplify manufacture, improve space utilization, and lower maintenance
expenses due to the use of short jumpers, single-sided configuration, and
other advantages, as compared with conventional distributing frames.
With the constant growth of subscribers in a given telephone office, the
problem of accommodation of ever-growing connector pairs is constant. The
known art includes many forms of main frames adapted to provide high space
utilization with maximum connector pair density, while still providing
adequate accessibility for servicing. To obtain such advantages, it is
customary to provide connector blocks in which availability of terminals
is possible only by providing protector terminals on one side of the frame
and connector terminals on the opposite side. It follows that a corridor
must be provided to allow accessibility to each side of the frame. While
it is, of course, possible to have a plurality of such frames disposed
upon a plant floor in mutually parallel relation, such arrangement
precludes maximum space utilization possible by mounting frames against
vertical walls or other areas where accessibility on one side only is
possible. In the case of two-sided frames, expansion in co-planar fashion
is difficult because of the lack of troughs and passages for jumpering and
the accompanying difficulty of tracing connections.
In our prior patent, with Albert Atun, U.S. Pat. No. 4,117,273, granted
Sept. 26, 1978, and assigned to the same assignee as the instant
application, there is disclosed an improved single-sided frame in which
some of the above mentioned problems are ameliorated to some degree by the
provision of structure in which connections and protector blocks are
positioned over a forward surface of the frame such that the exposed
surfaces of the blocks are parallel to the plane of the frame, and the
rear of the frame is provided with a large number of horizontal troughs
which cooperate with a relatively fewer number of vertical troughs to
accomplish horizontal and vertical jumpering. Using such construction, the
rear surface of the frames are wired before the frames are positioned
against a wall or other structure, and subsequent servicing is afforded
only on the forward or exposed surface of the frames. While these
constructions constituted an improvement over conventional main frame
structure, a relatively large number of both vertical and horizontal
cable-carrying troughs are required, which occupy space, and prevent the
utilization of such space for the mounting of terminal blocks of one type
or another. Additionally, in some installation situations, it is not
always possible to prewire the rear surface of the frame in such manner as
to preclude the possibility of future access.
SUMMARY OF THE INVENTION
Briefly stated, the invention contemplates the provision of an improved
telephone main distributing frame construction, in which certain of the
shortcomings of the prior art have been eliminated. The frame is intended
for single-sided administration and is comprised of a plurality of
vertical supports approximately eight feet high and arranged at intervals
of approximately seven inches center to center. Intra-vertical jumpering
is performed in interstices formed between the front and rear planes of
the frame elements, through a series of jumper rings which are mounted on
the individual frame elements. There are three large horizontally oriented
troughs located at the top, center and bottom of the frame along the
forward edges of the vertical supports to provide maximum accessibility
for horizontal jumpering. While the frame may be used entirely for random,
i.e. non-preferential assignment, the device may be utilized in such
manner that with a relatively high percentage of preferential assignment,
the maximum number of lines accommodated is substantially increased, the
limiting factor being the capacity of the various horizontal troughs for
intra-vertical jumpers. Because of relatively shallow depth, connecting
and terminal blocks of many known types may be employed which allow either
front cross-connect fields, or side access.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings, to which reference will be made in the specification,
similar reference characters have been employed to designate corresponding
parts throughout the several views.
FIG. 1 is a side elevational view of an embodiment of the invention.
FIG. 2 is a fragmentary front perspective view thereof.
FIG. 3 is a top plan view of a jumper ring.
FIG. 4 is a side elevational view of a jumper ring.
DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENT
In accordance with the invention, the device, generally indicated by
reference character 10, comprises broadly: a plurality of vertical planar
elements 14, an upper trough element 15, a medially positioned trough
element 16, a lower trough element 17, a plurality of grounding straps 18,
upper mounting means 19, and lower mounting means 20.
The planar elements 14 are substantially similar, each including a forward
vertical member 21, a rearward vertical member 22, and a plurality of
horizontal interconnecting members 23, preferably attached by welding. In
preferred form, the members 20 and 21 are approximately eight feet high,
so as to readily extend between floor and ceiling, and the elements 14 are
preferably maintained at seven-inch intervals to form an interstice which
is readily manually accessible. A plurality of jumper rings 25 are mounted
on each of the elements 14.
The upper trough 15 forms an open rectangular enclosure, and includes an
inner vertical member 30, an upper horizontal member 31, a lower
horizontal member 32, and overlapping outer vertical members 33 and 34,
all of the above members being preferably formed by bending a unitary
strip of metallic or synthetic resinous materials. Cables (not shown) are
inserted in the trough by merely moving the overlapping members 33 and 34
apart, and allowing them to return to abutted relationship thereafter.
The medially disposed trough 16 is generally similar, including an inner
vertical member 40, an upper horizontal member 41, a lower horizontal
member 42, and overlapping outer members 43 and 44. Attachment to the
planar elements 14 is preferably accomplished by spot welding (not shown)
or similar procedure.
The lower trough element 17 is positioned immediately above the floor upon
which the device is installed, and thus is in the path of the feet of
workmen, the lower end of a step ladder used by them, and similar moving
objects. In addition to being somewhat larger than the trough elements 15
and 16, it is, of necessity, considerably more sturdy. It includes an
inner wall 50, a lower wall 51, an outer wall 52, and an upper removable
cover 53.
The grounding straps 18 are preferably two in number, and serve not only as
a grounding means, but as structural members. The upper strap 60 and lower
strap 61 are connected to the rearward vertical members 22 of the element
14. They communicate at periodic intervals with flat copper strips 62
which are positioned within a hollow channel formed by certain of the
interconnecting members 23, the opposite ends of the strips contacting
connector blocks (not shown) which are mounted forwardly of the forward
vertical member 21.
The upper mounting means 19 is adapted to abut a ceiling or other
horizontal member (not shown) and includes forward and rearward angle
members 67 and 68 respectively, the upper surfaces 69 of which provide
physical contact. Optional end braces 71 may support a vertical member 72
which mounts a switch 73 for controlling illumination in the room in which
a plurality of devices are installed.
The lower mounting means 20 is generally similar, and includes forward and
rearward angle members 78 and 79, respectively, the lower surfaces 80 of
which are adapted to be supported by a floor (not shown). End braces 83
engage the lower end of the vertical member 72.
Jumper rings 85 are mounted on individual planar elements 14 so that the
loop portion thereof is disposed in a horizontal plane to accommodate
vertical jumpers. Each ring includes a mounting bracket 86 and a single
length of rod 87 bent to form a loop 88 having a point of entry 89 for
insertion of jumpers in well known fashion.
The forward vertical members 21 are provided at the forward edges thereof
with block mounting strips 90 upon which known terminal blocks 91 are
mounted. In the case of the blocks used for incoming cable pairs, the
blocks 91 will be mounted with principal plane thereof parallel to, if not
coplanar with, that of a planar element 14, so as to allow access on
either side thereof, and access rearward to rearwardly mounted boxes (not
shown) which may be connected to switching equipment located within the
building.
It will be observed that the connector blocks of varying types may be
employed at substantially any desired location, and the interconnection of
conductor pairs with terminals on the blank is a relatively simple matter
owing to ample accessibility.
Horizontal jumpering takes place in one of the three horizontal trough
elements lying substantially in the plane of the blocks being
interconnected. Vertical jumpering is facilitated by the presence of
jumper rings disposed in the interstice between adjacent planar elements
14. This interstice is approximately only 11 inches deep, and normally
only the first four or five inches will be required for vertical
jumpering.
It has been noted that the bottom trough element 17 is substantially larger
in cross-section than the medial and upper trough elements 16 and 15,
respectively. The trough element 17 will normally be employed for normal
subscriber service. In offices having a relatively large number of
preferential assignments, such connections are preferably made at points
above the trough element 16, as are trunk circuits and certain subscriber
line equipment, leaving the area below the center trough element for
connecting outside plant cable.
We wish it to be understood that we do not consider the invention limited
to the precise details of structure shown and set forth in this
specification, for obvious modifications will occur to those skilled in
the art to which the invention pertains.
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