Medical patient support table

A cantilever mounted table for an X-ray patient undergoing procedures requiring tilting the table head to foot or canting the table about its longitudinal axis allows a medical team free axis to one side and an end of the patient, and provides an improved collision sensing switch in the event the table strikes an obstruction below.

BACKGROUND OF THE INVENTION 
This invention involves apparatus for supporting a patient on a table 
during medical procedures under X-ray observation such as surgery, 
catheterization and dye angiography, or treatment of a patient in trauma. 
These procedures usually involve an anesthesiologist and a team of 
physicians and nurses around a table supporting the patient, and require 
space for an X-ray tube and receptor to be moved into and out of unlimited 
positions around the patient, while allowing the medical team free access 
to at least one side of the table, and allowing the anesthesiologist ready 
access to the head of the patient. The support apparatus should further be 
capable of tilting the patient around a transverse axis to raise or lower 
his head, and canting the patient by rotation generally around his 
longitudinal axis. However such movements may risk collision of the 
underside of the patient table with the floor, or equipment on the floor 
under the table. Collision sensing switches under the table have proven 
unsatisfactory because they may be inadvertently disabled by straps used 
to secure the patient to the table. 
It has been proposed to support a patient table by a connection offset from 
the longitudinal axis of the table, but this proposal, although generally 
satisfactory, causes movement of the patient's head relative to the 
anesthesiologist during tilting and canting, and increases the possibility 
of collision below the table. 
Accordingly it is an object of the invention to provide patient support 
apparatus which allows both tilting and canting of the patient by a 
simplified and more economical and efficient mechanism, and with decreased 
risk of collision below the patient table. 
A further object is to provide patient support apparatus which, without 
alteration of its components, can be adapted to extend either to the right 
or left side of its base and standard. 
SUMMARY OF THE INVENTION 
According to the invention apparatus for supporting a patient during 
medical procedures comprises a base with an upright standard, a cantilever 
beam extending horizontally from the standard and having a longitudinal 
axis, an elongate patient table extending at a right angle to the beam, a 
rotative attachment of the table to the free end of the beam to cant the 
table around an axis parallel to the length of the table, and a rotative 
coupling of the beam to the standard to tilt the table around an axis 
transverse to the table so that a patient on the table can be both canted 
about a head to foot axis, and tilted head up or head down about a 
transverse axis. 
Further according to the invention the apparatus includes a motor for 
turning the beam about its longitudinal axis and tilting the table, an 
additional motor for canting the table about its longitudinal axis, a 
crank extending laterally from the beam, a drive link between the motor 
and the crank, a loose coupling of the link to the crank, and a switch 
sensing movement of the crank relative to the link to disconnect power to 
either of the motors when the table collides with an obstruction below. 
Still further according to the invention the end of the beam comprises a 
constant diameter collar extending at right angles to the beam between 
identical open ends, and a plate rotatively supported in the collar and 
having means for attachment to the table, the plate being adapted to fit 
in either open end of the collar so that the table can be rotatively 
attached at either side of the beam and extend to the right or left of the 
standard.

DESCRIPTION 
FIGS. 1 and 2 show diagrammatically two alternative overhead dispositions 
of patient support during X-ray observation. In FIG. 1 the patient P is 
positioned on a cantilever table T with his feet adjacent the left side of 
a beam 2 extending from a standard 1. A stand S for an X-ray source X and 
an X-ray receptor R is moveable from the head toward the feet of the 
patient. Medical personnel M have the most advantageous access to the head 
and thorax of patients being catheterized in cardiac procedures with this 
disposition. But, in other procedures, access by an anesthesiologist to 
the patient's head would be obstructed by the X-ray stand. Thus hospitals 
require roughly an equal number of installations with the table extending 
from the right and left sides of the beam so that the patient can be 
supported with his head to the beam for access by an anesthesiologist and 
equipment, and with the foot end of the table free or access by the X-ray 
stand, or vice versa. 
The structure of apparatus for supporting a patient during the medical 
procedure is shown generally in FIGS. 3, 4 and 7 and comprises a base 1 
anchored on an operating room floor, with an upright standard 2. The 
standard has vertical rails 3 which are engaged by linear bearings 4 on a 
carriage 6 which rides up and down on the rails. On the carriage 6 is a 
heavy duty rotary bearing 8 on which is attached a cantilever beam 7 whose 
longitudinal axis extends horizontally from the standard. At its free end 
the cantilever beam 7 forms a cylindrical collar 9 extending at right 
angles to the beam with a continuous diameter and with identical open 
ends. 
As shown exploded in FIG. 8 the collar is adapted to receive two rotary 
bearings 11 in which is journalled the stub shaft 12 of a table bracket 
13. One end of the collar is closed by an apertured disk 14 screwed to the 
collar, and the other end is closed by a circular plate 16 with a circular 
boss 17 screwed to the stub shaft 12. Secured to the bracket 13 is a table 
top T adapted to support the patient under examination and extending at a 
right angle to the longitudinal axis of the beam 7. 
Mounted at the top of the standard 2 is a first motor M1 which, through a 
gear box 18, drives a screw 19 engaging a nut 20 on the carriage so as to 
raise and lower the carriage and the patient table. 
As shown particularly in FIGS. 4, 5 and 7, a double crank arm 21 welded to 
the beam 7 extends laterally from the beam parallel to the carriage 6. A 
second, tilt motor M2 (FIGS. 4 and 7), through sprockets 22 and 23 and a 
connecting chain, drives a screw threaded through a nut 26 pivotally 
secured between the two arms of the crank 21 by a pin 27. When energized 
the second motor rotates the beam about its longitudinal axis so as to 
effect Trendelenburg tilting of the patient table about an axis transverse 
of the patient. 
As shown in FIG. 3, a third, cant motor M3 is mounted on the side of the 
beam from which the table extends. Through a gear box 34 the third motor 
rotates tubular housing 33. One end of the housing is pivotally anchored 
in a yoke 36 on the end of the beam, and the other end acts as a nut. One 
end of the screw 32 is pivotally connected to an extension 37 from the 
rotating bracket 13 on which the table T is mounted, and the other end of 
the screw moves within the housing 33. Reversible drive of the third motor 
M3 rotates the housing and cants the table and patient about an axis which 
is substantiallY the same as the longitudinal axis of the patient. 
Reverting to FIGS. 5 AND 6, the pin 27 connecting the drive screw 24 of the 
second motor M2 to the beam crank arms 21 loosely engages in a slot 28 in 
the crank arms such that the weight of the patient table reflected back 
through the beam lifts the slot in the crank arms upwardly against the pin 
27 at the lower end of the slot. In this position the enlarged end of the 
pin engages the contact 29 of a spring collision switch S1 attached to one 
of the crank arms adjacent the slot thereby holding the switch open (FIGS. 
4, 5 and 6). If, during a critical procedure with a patient on the table, 
the table should be driven by any one of the three motors M1, M2 or M3 
into collision with any obstruction below the table, the table would he 
lifted relative to the beam causing the beam crank arm 21 to rotate the 
collision switch S1 away from engagement with the pin 27 thus allowing the 
collision switch to close and energize a relay 33. The relay would then 
open its contacts 34, 35 and 36 between a motor control circuit 37 and the 
respective motors disabling all of them (with the exception that the motor 
control circuit would allow the first motor M1 to raise the patient table 
away from collision). 
Thus, no matter which one or combination of the three motors necessary to 
provide elevation, tilting and canting causes the collision, the single 
collision switch on the beam crank arm will detect the collision and 
arrest it instantly. 
It should be understood that the present disclosure is for the purpose of 
illustration only and that the present invention includes all 
modifications and equivalents falling within the appended claims.