U.S. patent number 3,575,368 [Application Number 04/794,204] was granted by the patent office on 1971-04-20 for vertically adjustable counterbalancing x-ray tube head suspension support apparatus.
This patent grant is currently assigned to Westinghouse Electric Corporation. Invention is credited to William E. M. Jones, Bernard Miller, Eugene P. Thomas.
United States Patent |
3,575,368 |
Thomas , et al. |
April 20, 1971 |
VERTICALLY ADJUSTABLE COUNTERBALANCING X-RAY TUBE HEAD SUSPENSION
SUPPORT APPARATUS
Abstract
Described is a vertically adjustable counterbalancing suspension
support apparatus embodied in a floor mounted mobile X-ray tube
column. The exemplified load, an X-ray tube head, is mounted on a
vertical carriage movable along a mobile-based column containing an
elongated circumferentially-encased helical compression spring
extending vertically therein for counterbalancing the tube head and
carriage. A dual suspension cable arrangement transmits the
carriage load to the lower and live end of the compression spring
via respective spring-pickup-compensating fusees at the top of the
column and a pair of spring-travel-reducing pulley arrangements at
such live end. A combined tension-equalizing-and-safety-lock member
connects the support cables to the loaded carriage.
Inventors: |
Thomas; Eugene P. (Baltimore,
MD), Jones; William E. M. (Pittsburgh, PA), Miller;
Bernard (Pittsburgh, PA) |
Assignee: |
Westinghouse Electric
Corporation (Pittsburgh, PA)
|
Family
ID: |
25162012 |
Appl.
No.: |
04/794,204 |
Filed: |
January 27, 1969 |
Current U.S.
Class: |
248/572; 248/647;
248/669; 248/676 |
Current CPC
Class: |
F16M
11/046 (20130101); F16M 11/42 (20130101); B66B
17/12 (20130101); A61B 6/447 (20130101); F16M
2200/047 (20130101) |
Current International
Class: |
B66B
17/00 (20060101); B66B 17/12 (20060101); A61B
6/00 (20060101); F16M 11/24 (20060101); F16M
11/02 (20060101); F16M 11/04 (20060101); F16M
11/20 (20060101); A47g 029/00 (); F16m
011/06 () |
Field of
Search: |
;248/162,404,123,297,292,327,328,329,330,331,332,333,334,335 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Parsons, Jr.; Marion
Claims
We claim:
1. A vertically adjustable counterbalancing X-ray tube head
suspension support apparatus, comprising:
an X-ray tube head to be positioned selectively at different
elevations;
a floor-mounted hollow vertical column of rectangular cross section
having oppositely facing horizontally spaced-apart exterior guide
channels extending lengthwise along its one rectangular side at
respective edges thereof;
a vertical carriage supporting said X-ray tube head and having
rollers thereon in rolling contact with said guide channels;
a pair of fusees and respective attached drums disposed within said
column near its top for rotation about fixed horizontal axes;
a tubular spring housing member fixed relative to said column and
extending upwardly therewithin;
an inwardly extending stop member affixed to the upper end of said
spring housing member;
an elongated helical compression spring disposed in said spring
housing member with its upper end abutting said stop member;
a pair of pulleys disposed within said helical compression spring
in upwardly exerting thrust-transmitting connection to its lower
end;
a pair of parallel-arranged flexible cables anchored at their one
end to said column above said spring housing member, extending
downwardly therefrom to and around said pulleys, thence upwardly to
and around the respective drums and fusees in continuously wound
relationship, thence downwardly to said carriage; and
an elongated horizontal rockable member extending laterally between
said guide channels, having opposite pointed ends normally disposed
in proximity to walls of said guide channels extending
perpendicular of said member, pivotal suspended connections with
said cables at opposite sides of its mid length, and a laterally
constrained pivotal support connection with said carriage at a
location separated from such pointed ends a distance greater than
the mid distance between such perpendicular guide channel walls.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention:
Vertically adjustable counterbalancing suspension support apparatus
for devices, instruments, or the like, such as X-ray tube heads,
mounted for guided travel vertically.
2. Description of the Prior Art:
Vertically adjustable counterbalancing suspension support apparatus
employing flexible suspension cables for support of relatively
heavy items such as X-ray tube heads mounted on vertical columns
often are characterized by considerable bulk, complexity, and/or
weight resultant from the nature of the construction of such
apparatus under requirement for a high degree of assurance against
failure of the apparatus to maintain support of the load over a
prolonged period of time.
SUMMARY
The present invention, is suspending the vertically adjustable
load-bearing carriage or mounting means by a pair of cables, either
of which alone is capable of supporting such loaded carriage,
together with inclusion of a safety lock for the carriage which is
effectuated responsively to loss of support by either cable,
fail-safe operation of the support apparatus with respect to
suspension cable failure is assured. By virtue of employment of a
single elongated helical compression spring in conjunction with
fusees for counterbalancing the load-bearing carriage, the weight
of the apparatus can be made significantly less than where a
counterweight means is employed. By virtue of circumferential
encasement of the compression spring, its reliability is assured
against separation at any of its turns and a degree of simplicity
relative to use of a plurality of parallel-arranged tension springs
is afforded. And, by virtue of connecting the cables to the live
end of the compression spring via jockey pulleys, the travel
required for spring compression is one-half that of the
load-bearing carriage, thus affording use of a relatively short
spring and thereby contributing to a saving in space requirement
for such spring.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation view, partly in outline and partly in
section, of a floor-mounted mobile X-ray column embodying the
invention;
FIG. 2 is a front elevation view of the portion of the apparatus
within the dot-dash circle A in FIG. 1;
FIG. 3 is a front elevation view of the portion of the apparatus
within the dot-dash circle B in FIG. 1; and
FIG. 4 is a front elevation view of the portion of the apparatus
within the circle C in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment of the invention is exemplified in
conjunction with a floor mounted mobile X-ray column 5 projecting
vertically from a wheel-supported base 7, as shown in FIG. 1. The
column 5 is constructed of metal, is hollow, and of generally
rectangular cross section, with oppositely-facing guide channels 9
formed therein which extend along its length for directing vertical
movement of a tube head carriage 12 via carriage rollers 14
disposed in such channels. For suspension support of the carriage
12, one end of a spaced-apart pair of flexible plastic-covered
aircraft cables 16 about one-eighth inch in diameter, only one of
which is shown in FIG. 1, are anchored to the tube head carriage 12
via a combined tension-equalizing and safety lock member 18
extending between the guide channels, as shown in FIG. 2. These
support cables 16 in turn extend upwardly along the carriage guide
channels 9, across respective relatively wide cable guide pulleys
20 on the column 5 onto the spiral grooves of respective fusees 22,
thence around multigrooved drums 24 affixed to the fusees, thence
downwardly within the column around a pair of respective jockey
pulleys 26 coupled to a lower and live end of a helical compression
spring 28 within the column, and then upwardly through such spring
to cable anchors 30 at the top of the column.
The compression spring 28 is cylindrical and encased about its
periphery in a hollow tubular spring housing member 32 attached at
its lower end to the wheel-supported base 7 at the bottom of the
column 5. An inwardly-extending annular stop member 34 affixed to
the upper end of the spring housing member 32 forms a shoulder
against which the upper end of the compression spring 28 abuts, and
the outer periphery of such spring is in slidable engagement with
the inner surface of such housing member.
Referring to FIGS. 1 and 4, jockey pulleys 26 are rotatably carried
between the arms 36 of a clevis 38 on a common shaft 40, and the
clevis has a thrust transmitting rotary connection with the upper
end of a threaded spring adjustment screw 42 via a swivel member
44. The adjustment screw in turn extends centrally through and is
in screw-threaded connection with a disc-shaped thrust member 46
which abuts the lower end of the compression spring 28.
In normal operation of the apparatus, in any given vertical
position of the carriage 12, the degree of compression of the
spring 28 commensurate with such position creates a tension in the
cables 16 which is transmitted to the carriage via the drums 24 and
fusees 22 adequate to suspend such carriage and its tube head 50
load. As the tube head carriage 12 is moved downwardly, the cables
16 will unwind from the fusees 22 and leave same at progressively
decreasing diameter portions of the spiralling fusee grooves as the
cables wind upwardly onto the drums 24 and pull the lower end of
the compression spring 28 upwardly via the jockey pulleys 26 an
amount equal to one-half the downward travel of the carriage. Such
increased longitudinal compaction of the spring 28 increases
tension of the cable portions passing around the pulleys 26 and
winding onto the drums 24. Such increased tension, however, in
accord with the well-known characteristics of fusees, is
compensated for by the fusees 22 which maintain tension of the
cables playing out from such fusees constant and collectively equal
to the load imposed thereon by the carriage 12 and its load 50.
When the tube head carriage 12 is moved upwardly, the cables 16
will wind onto progressively larger diameter portions of the fusees
22 as a result of the compression spring 28 unwinding the cables 16
from the drums 24 attached to such fusees, and the resultant
diminished spring force is compensated for by the fusees to
maintain the counterbalancing support of the tube head carriage 12,
and its load 50. It will be understood that the fusees 22 and the
drums 24 attached thereto are so constructed and arranged as to
accept storage of the cable lengths necessary to accommodate
vertical travel of the carriage 12 for substantially the entire
length of the column 5, and that the cables 16 are suitably secured
against slippage on the fusees and drums.
In accord with a feature of the invention, the combined
tension-equalizing and safety lock member 18 via which the cables
16 are connected to the tube head carriage 12 is simply in the form
of a substantially flat metal plate, FIG. 2, which is pivotally
connected at 52 near its top edge midway between its ends which are
tapered downwardly, as viewed in the drawing, to relatively sharp
edges 54 that are disposed with slight clearance adjacent to the
sidewalls 56 of the carriage guide channels 9 at the forward edges
of the column 5. During normal operation of the apparatus, with
both cables 16 intact, the member 18 is free to tilt slightly about
its pivotal connection 52 with the carriage 12 in the presence of a
moderate degree of difference in cable lengths which are anchored
to such member equal distances at opposite sides of such pivotal
connection. However, the member 18 is so proportioned that the
distance from the pivotal connection 52 to either sharp edge 54 is
greater than the distance from such pivotal connection to either
guide channel wall 56, so that upon separation of one of the cables
16, the torque reaction between the horizontally constrained
vertically movable pivotal connection 52 and the nonseparated one
of the cables causes the member 18 to turn about such connection
and bring the corresponding sharp edge 54 of the member into
locking engagement with the respective guide channel wall 56 and
prevent the carriage 12 and its load 50 from being lowered, even
though the remaining intact cable is capable of alone supporting
the load and affording opportunity for raising the carriage. Such
lockout against downward movement serves as indication of the
existence of a faulty cable in a manner that requires attention
before the apparatus can be operated in a useful manner.
* * * * *