US 3304116 A
Description (OCR text may contain errors)
Feb. 14, 1967 l H. H. STRYKER 3,304,116
MECHANICAL DEVICE Filed March 16. 1965 4 Sheets-Sheet 1 Feb. 14, 1967 H. H. STRYKER 3,304,116
MECHANICAL DEVICE Filed March 16, 1965 4 Sheets-Sheet 2 /Ja /55 /7 /M f//MTf/z/fw 4 Sheets-Sheet 5 Filed March 16. 1955 Kraan/fw Feb. 14, 1967 H. H. STRYKER 3,304,116
MECHANICAL DEVICE Filed March 16. 1965 4 Sheets-Sheet 4 lll lt l l m l 72 v mi I BY zaim, My/7% United States Patent O 3,304,116 MECHANICAL DEVICE Homer H. Stryker, Kalamazoo, Mich., assigner to Stryker Corporation, Kalamazoo, Mich., a corporation of Michigan Filed Mar. 16, 1965, Ser. No. 440,093 6 Claims. (Cl. 296-20) This invention relates in general to a wheeled carriage for supporting a patient and, more particularly, to a type of carriage having a vertically adjustable support frame upon which a stretcher can be removably placed for the purpose of safely supporting and transporting a patient disposed thereon in avhorizontal or tilted position.
Wheeled `carriages of many types have long been in use for moving patients who are seriously ill or seriously injured. In some instances, the patient must be transferred from the stretcher to the carriage, which is often undesirable, and in other instances the stretcher is placed upon the carriage. However, existing carriages of the latter type are often diiiicult to maneuver and they are designed either expressly for the purpose of moving the patient or so that they are not adapted for use in treating or performing any other service related to the needs of a patient. Accordingly, a seriously ill or seriously injured patient must often be moved from this type of stretcher-supporting carriage into or onto another carriage or bed or operating table before treatment can be administered. Frequently, this results in a dangerous loss of time, or a risk of further injury to the patient.
Often, during the initial treatment of an injured patient who has been delivered to the emergen-cy room of a hospital, it is necessary to move the patient immediately to other rooms in the hospital for emergency ex-amination and special tests. With existing equipment, it is usually necessary to place the patient on some type of wheeled carrier during each move and, in many instances, the patient must be transferred from the carrier to a bed or table for the examination or testing, mainly because of the inadequacy of existing carriers to serve as a patient support during the examination or treatment. During the transfer of the patient, it is common practice to roll or slide the patient from the carrier to the bed or vice versa. Unless the carrier has some means, which many do not, for holding it against the bed, considerable care must be exercised by the attendants to prevent a fall of the patient between the bed and carrier. Thus, the loss of valuable time and the risk of further injury could be avoided by providing a patient-carrying apparatus which can also serve as the patient support during the treatment or testing.
Some attempts have been made to use the substantially conventional hospital bed or operating table as a patient carriage, but such devices simply are not designed for this service. For example, they are usually too wide, too heavy, too expensive, too diiiicult to handle, or otherwise inadequate for this purpose.
After considering this problem for many years, I have realized that a new type of patient carrier was needed. That is, proper patient care, particularly under emergency conditions, requires a carriage which is adapted to receive and safely support a stretcher upon which the patient is brought into the hospital, so that the patient need not be removed from the stretcher. Proper emergency care also necessitates a carriage which has the basic essentials and capability of performance of an emergency operating table, which can serve efiiciently, at least temporarily, as a hospital bed, and which is at least as maneuverable as any wheeled, patient-carrying device presently in existence foregoing paragraphs, it became apparent that the maneuverability required of the patient carriage for moving the patient around the hospital could be a disadvantage when the carriage is used as an operating table. Moreover, other such confiicts could develop between the various parts required to perform the multiple functions desired.
Accordingly, the objects of the invention have been to provide:
(l) A multiple purpose, wheeled carriage which is capable of supporting a stretcher carrying a patient who requires examination and/or treatment which is capable of quick and easy movement from one place to another within a hospital or other building, and which can be used as a temporary bed or emergency operating table for a patient.
(2) A wheeled, patient carriage, as aforesaid, having wheel locking means, having a stretcher support with side rail means for patient security, having easily operated lift mechanism for effecting vertical movement of the patient support, having means for raising and/or lowering one end of the patient support with respect to the other, and having a frame structure which is light in weight, sturdy in construction, simple to maneuver, easy to clean after use, and capable of relatively inexpensive manufacture, particularly in view of the services which it is able to provide.
Other objects and purposes of this invention will become apparent to persons acquainted with this type of equipment upon reading the following descriptive material and examining the accompanying drawings, in which:
FIGURE l is -a perspe-ctive view of the wheeled patient carriage to which this invention relates.
FIGURE 2 is an end elevational view of said patient support as seen from the head end thereof.
FIGURE 3 is a broken top view of said wheeled carriage with the stretcher removed therefrom. j
FIGURE 4 is a sectional view taken along the line IV--IV in FIGURE 3.
FIGURE 5 is a sectional View taken along the line V-V in FIGURE 4.
FIGURE 6 is a sectional view taken along the line VI-VI in FIGURE 3.
FIGURE 7 is a sectional view taken along the line VII-VII in FIGURE 2 with parts thereof in their raised positions.
FIGURE 8 is a broken view taken along the line VIII- VIII in FIGURE 2.
FIGURE 9 is a broken, bottom view of the wheeled carriage.
FIGURE l0 is a sectional view taken along the line X-X in FIGURE 2.
FIGURE l1 is a fragment of FIGURE 2 with the wheel lock mechanism in its locked position.
FIGURE l2 is a sectional View taken along the line XII-XII in FIGURE 2.
FIGURE 13 is a sectional view taken along the line XIII-XIII in FIGURE 3.
FIGURE 14 shows a view similar to -FIGURE 13 with parts thereof in different positions of operation.
For convenience in description, the terms upper, lower, front, rear, left and right, as used herein, will have reference to the wheeled support of the invention as appearing in FIGURE 2, which discloses a rear end elevational view. The terms innen outer Vand derivatives thereof will have reference to the geometric center of said wheeled support and/ or parts thereof.
General construction The objects and purposes of the invention, including those set forth above, have been met by providing a Patented Feb. 14, 1967` wheeled carriage for patient transport having a wheeled undercarriage upon which a support frame is mounted for vertical adjustment. The undercarriage is movably supported by four swiveled casters arranged in a rectangle and a fifth wheel located near the center of sa-id rectangle for `movement into and out of engagement with the supporting surface engaged by the four casters. The support frame is arranged to hold a stretcher in a manner completely safe "for the patient supported on the stretcher. The various controls for `operating the carriage are easily accessible for manual and/ or pedal operation.
Detailed description The wheeled carriage (FIGURES 1 and 2) is comprised of a wheeled base or undercarriage 11 having an I- shaped base frame 12 and a pair of upstanding support columns 13 and 14 supported upon the re-ar and front ends, respectively, of the base frame 12. A support frame 17 is connected to the upper end of the support columns 13 and 14 for the purpose of safely holding a patient support, such as a stretcher 18, in a substantially horizontal and safe position. Y
The base frame 12, which is preferably fabricated from tubular metal members, has a oentral lengthwise beam 19 and a pair of parallel end beams 22 and 23 secured respectively' to the rear and front ends of the central beam 19 in any conventional manner, as by welding. Four swiveled casters 25, 26, 27 and 28 are pivotally supported near the ends of the beams 22 and 23, one caster being on each end of an end beam, so that they substantially define a rectangle and so that the wheels of said casters, such as the wheel 31 of the caster 25, will all simultaneously engage a' substantially fiat supporting surface, such as a floor. The caster 25 may be lof a substantially conventional type. A locking mechanism 32 (FIGURES l, 2, l9 and 10) is pro vided to prevent castering or pivotal movement of the above-mentioned casters and rotation of their respective wheels when castering or rotation are not desired. As shown in FIGURE 9, the locking mechanism includes a lengthwise element 33, which is preferably secured near the center thereof by means, such as the screws 34, to the lower side of the central beam 19 near its center, and a pair of` end elements 36 and 37 which may be secured, as by welding, to the rear and front ends, respectively, of the lengthwise element 33. The elements 33, 36 and 37 are preferably made from metal bar stock and the lengthwise element 33 is resiliently flexible. Also, the end` elements 36 and 37 are preferably located directly beneath the beams 22 and 23, respectively, and extend near the ends thereof. Circular lock elements 38, 39, 4f) and 41 are secured, as by welding, to the opposite ends of said end elements 36 and 37, so that they are preferably concentric with the pivot axes of the casters 25, 26, 27 and 28, respectively. The lengthwise element 33 normally holds the end elements 36 and 37 closely adjacent the end beams 22 and 23 so that the above-mentioned circular lock elements are spaced above the wheels on said swiveled casters and radially spaced from the yokes of the casters, such as the yoke 44 of the caster 25L (FIGURES 2 and 9).
A pivot rod 45 (FIGURES 6, 9 and 12) extends completely through and lengthwise of the central beam 19 and also through the adjacent portions of the end beams 22 and 23 in which it is pivotallysupported. A pair .of eccentrics 47 and 48 (FIGURE 9) are secured to the opposite ends of the pivot rod 45 for rotational movement therewith around the axis of the pivot rod. The eccentrics may be adjustably secured to the pivot rod 45 by means of a slet screw, such as the set screw 49 on the eccentric 47 in FIGURE l0. A pair of plates 51 and 52 are secured to the opposite ends of the central beam 19 for engagement by the eccentrics 47 and 48 when they are pivoted by the rod 45, to simultaneously move said plates, hence their adjacent end beams 22 and 23, respectively, downwardly, whereby the lock elements 38, 39, 40 and 41 simultaneously engage the Wheels on the casters 25, 26, 27 and 28, re-
spectively, thereby locking said casters against pivotal movement and their wheels against rotation. The eccentrics 47 and 48 are arranged so that they rotate about 90, as indicated by the sidewardly projecting end portion 53 of the rod 45 in FIGURES 2 and 11, for the purpose of moving the eccentrics from their unlocking positions to their locking positions. A stop 54 on the end beam 22 is arranged to positively limit the pivotal movement of the eccentric 47, hence the eccentric 48, Aapproximately Within said 90 range. A manually engageable handle bar 56 is secured to the eccentric 47 and extends radially therefrom for moving the eccentrics into their locking positions. The unlocking operation can be performed merely by placing a foot on the end portion 53 when it is in its FIGURE 11 position and pressing downwardly thereon. As soon as the end portion 53 has moved a short distance, the eccentric will pass its bottom dead center or lowy point after which the resiliency of the lengthwise element 33 acting through the plate 51 will tendto urge the continued rotational movement of the eccentric upwardly until the end elements 36 and 37 are again in their raised positions as shown Iin FIGURES 1 and 2. The locking mechanism 32, hence the lock elements thereof, are held in their lowered locking positions of FIGURE 11 by the fact that the eccentrics 47 and 48 move during the locking operation slightly past their bottomdead center or lowermost positions as shown in FIGURE 11 witfh respect to the eccentric 47. Thus, the resilient lengthwise element 33 is urging said eccentric 47 in a counterclockwise or locking position, against the stop 54 A fifth wheel 60 is rotatably supported upon the lowermost ends of the arms 61 and 62 of a U-shaped wheel support 63 which extends around the central portion o-f the central beam 19 (FIGURES l, 13 and 14). The wheel is supported by an axle 64 and the wheel support 63 is pivotally connected near its upper end to the beam 19 by means of a pivot shaft 66. The top plate 67 of the wheel support 63 is flat and the pivot shaft 66 is preferably directly beneath one edge thereof. The opposite edge 68 of said plate 67 is engageable by a lever 69 which is pivotally supported by the bracket 72 upon the beam 19. Spring means 73 disposed between the lever 69 and the upper surface of the beam 19 resiliently resists movement of said lever 69 'in a clockwise direction as appearing in FIGURE 13. However, when the plate 67 is urged toward the beam 19 by a substantial force, as by the force which can be produced by placing a foot on the plate 67 and moving it firmly downwardly, the lever 69 will pivot with the bracket 72 in a clockwise direction to permit the edge 68 of the plate 67 to move under the holding tip 74 of the lever 69 after which the spring then urges the lever into its original position on top of the plate as shown in FIGURE 14. The axle 64 may have its center line slightly to the rear of the center line of the pivot shaft 66 so that the weight imposed upon the fifth wheel 60 tends to hold it in its lowered position and thereby relieve the lever 69 from opposing such force. An elongated spring 76 is connected between the wheel support 63 beneath the beam 19 and a point on the beam for the purpose of urging the wheel toward its raised FIGURE 13 position as soon as the lever 69 is urgedv in a clockwise direction from its FIGURE 14 position, which can be done by placing a foot on the front end of the lever. The spring 76 also holds the fifth wheel in its raised position. The raised position of the fifth wheel 6@ is above the plane indicated by the numeral 77 in FIGURE 13 defined by the lowerrnost points on the caster wheels, and the wheel extends below such plane as shown in FIGURE 14, when the wheel is moved into its lowered position.
The support columns 13 and 14 (FIGURE l) include outer casings 78 and 79, respectively, which enclose the lower portions of a pair of hydraulic cylinders 82 and 83 having upwardly extending pistons or actuating arms 84 and 85.
der 82 and 83 is respectively connected to hydraulic pumps 87 and 88 which are arranged to urge the arms 84 and 85 upwardly. In this particular embodiment, the hydraulic cylinders 82 and 83 may be of the type wherein the reservoir of fluid used for raising the actuating larms is provided by a casing around the cylinder. Thus, when it becomes desirable to lower the actuating arms 84 and 85, conventional bypass valves 89 and 90 (FIGURES 4 and 6), respectively, can be opened in said pumps for the purpose of permitting the hydraulic fluid to move back into the reservoir space.
As shown in FIGURES 4 and 5, the hydraulic pump 87 has a piston rod 92 which is connected by linkage 93 to a foot operated lever 94 whereby liquid is transferred from said reservoir to raise the actuating arm 84. The hydraulic pump 88 is similarly connected to linkage 96 which is connected by a tiebar 97 to the linkage 93 for operating the pump 88 simultaneously with operation of the pump 87 by the lever 94.
The bypass valve 89 is connected by a connecting rod 9S and a pair of crank arms 99 and 100 to a manually rotatable tube 103 which is housed in a cylindrical casing 104. The tube 103 extends from the rearward end of the casing 104 where it can be manually engaged and rotated to effect opening of the bypass valve 89. In a similar manner, the bypass valve 90 is connected by a rod 106 and a pair of `cranks 107 and 108 (FIGURE 6) to the tube 109 Within the cylindrical casing 110 for effecting opening of said bypass valve 90 from the rearward end of the carriage.
The support frame 17 (FIGURES 1, 2 and 3) is substantially rectangular in shape and includes a pair of side elements 115 and 116 and a pair of integral end elements 117 and 118. A pair of cross braces ,120 and 121 extend between the side elements 115 and 116 near the rear and front ends respectively. In this embodiment, the said side and end elements may be fand preferably are fabricated from metal tubular materials. The cross braces 120 and 121 are preferably fabricated from bar stock.
The actuating arms 84 and 85 have crossheads 122 and 123 (FIGURES 5 and 6) rigidly secured to their upper ends. A pair of end tubes 125 and 126 are pivotally secured into the opposite ends of the tubular crosshead 122 and are connected by means of the sleeves 127 and 128 to the side elements 115 and 116, respectively, for supporting the rear end of the frame 17 upon the crosshead 122, hence upon the rear support column 13. A pair of end tubes 130 and 131 (FIGURE 3) are similarly and pivotally received into opposite ends of the crossheads 123 and connected at the-ir outer ends by means of the sleeves 132 and 133 to the side elements 115 and 116, respectively. The sleeves 132 and 133 are also free to slide along the side elements 115 and 116, respectively, between the locking collar 135 and the cross brace 121 when one end of the frame 17 is moved upwardly and downwardly with respect to the other, which movement is permitted by the pivotal support `of the end tubes 125 and 126 and 130, 131 Within the crossheads 122 and 123, respectively.
The cross braces 120 and 121 are positioned `and shaped as shown in FIGURE 2 so that the side frame elements 136 and 137 of the stretcher 18 can be snugly cradled between the side elements 115 and 116 of the support frame 17. The stretcher 18 may be of a substantially conventional type wherein said side frame elements 136 and 137 are portions of a continuous tubular member which extends completely around the stretcher. As shown in FIG- URES l and 8, a piece of durable material, such as canvas 139, is stretched around the frame 138 and the edges thereof are provided with metal eyelets 141 by means of which resilient elements 142 are connected for the purpose of holding the canvas upon the frame. Cross braces 143 and 144 between the side elements 136 and 137 strengthen the stretcher. Said cross braces 143 and 144 are preferably arched downwardly away from the canvas 6 139 to minimize discomfort to the occupant of the stretcher.
The support frame 17 has a pair of side rails 150 and 151 (FIGURE 3) which are supported upon the side elements and 116 .of said frame for adjustable positioning around the lengthwise axes of said side elements. Specically, lthe side rail is comprised of a U-shaped member 152, the opposite ends of which are connected to sleeves 153 and 154 rotatably supported upon the side elements 115. A cross tube 156 is secured to the opposite end portions of the member 152 adjacent the sleeves 153 and 154 and extends substantially parallel with the length-- wise center portion 157 of the U-shaped member 152. A piece of fabric, such as canvas, is wrapped around the cross tube 156 and center portion 157 to provide a wall or shelf. A pair of straps 159 are threaded through slits 160 for holding an ar-m, for example, against the side rail 150. As shown in FIGURES l, 2 and 3, the side rail 150 can be held against pivotal movement with respect to the side element 115 in a variety of different positions varying from upwardly extending land sidewardly extending to downwardly extending. This positioning is accomplished by means of a pin 162 which is secured to and extends radially outwardly from the side element 115 (FIG- URE 7) adjacent the sleeve 154 which has a plurality of notches 163 in the front edge thereof into which said pin 162 is removably receivable. A spiral spring 164 encircles the side element 115 Iand is held under at least some compression between the sleeve 153 and the cross brace 120 whereby the sleeve 154 is continuously urged against the pin 162, thereby preventing accidental dislodgement of the pin 162 from a notch 163 and an unintentional changing in the position of the side rail 150. If necessary or desirable, a duplicate pin and notch arrangement could be provided between the side element 115 and the front end of the sleeve 153.
The side rail 151 (FIGURE 3) is preferably identical with the side rail 150 and, therefore, has a U-shaped member 166 which is connected to the side element 116 by sleeves 167 and 168. The side rail 151 includes a fabric cover 169 and it is adjustably held in position by means including the spring 171 and a pin and notch arrangement, not shown, which may be associated with the sleeve 168 and side element 116 as discussed above with respect to the side rail 150.
A rod 172 is supported upon the side element 115, for example, by means of a sleeve 173 which is rigidly secured to one end of said rod 172 and rotatably and slideably supported upon said side element. The rod 172 has a hook 174 (FIGURE 3) at its upper end for the purpose of supporting a bottle of blood, for example, during a transfusion. The sleeve 173 can be adjustably held in one or more positions with respect to the side element 115 by means of the pin 176 secured to said side element 115 and the notch 177 in said sleeve 173 into which said pin is slideably and removably receivable. A spiral spring 178 between the sleeve 173 and the locking collar 135 is held under compression to continuously urge the sleeve 173 against the pin 176.
A bracket 181 may be mounted upon the end beam 22 for the purpose of supporting a tank 182 and the other necessary apparatus for applying oxygen to a patient.
A basket 183 is supported upon the front ends of the cylindrical cases 104 and 110 by means of the bracket 184 at the front end of the wheeled base 11. Said cylindrical casings 104 and 110 extend through the upper ends of the rectangular casings 78 and 79 for the purpose of adding further strength to the assembly.
Operation While the manner of operating the above-described carriage is probably self-evident from such description, a brief summary of same is now given. With the carriage 10 in its FIGURE l position, the swiveled casters 25 through 28 are all in contact with a supporting surface,
such as a floor, and the carriage can be moved in practically any direction which, of course, makes it somewhat difficult to handle when moving down a hall or through a door. Accordingly, to facilitate 4such handling, the wheel support 63 for the fifth wheel 60 is moved from its FIGURE 13 position to its FIGURE 14 position merely by placing a foot upon the top plate 67 and urging same downwardly until the lever 69 snaps over the edge 68 of said plate. Where the supporting surface is substantially level, two of said swiveled casters will be raised above the surface of the fioor so that the wheeled carriage will then be supported upon the fifth wheel 60 and two of the casters, usually the rear casters 25 and 26, due to the concentration of weight at that end, particularly when a patient is supported upon the wheeled carriage. If the carriage is now moved, the fifth wheel 60 serves as a guiding wheel and the carriage is steered by shifting the rear end of the carriage which can be manually engaged by the attendant. Obviously, if the front casters 27 and 28 are in Contact with the surface of the oor, then the front end of the carriage is shifted laterally to effect steering operation.
If a patient is brought in on a stretcher, such stretcher can be placed immediately upon the support frame 17 for movement to another location, for treatment and operation. If the patient is to be moved to another location, the fifth wheel is moved into its FIGURE 14 position, as aforesaid, the side rails 150 and 152 are preferably moved into their upright positions as shown in FIGURE 1 with respect to the side rail 150 and the patient can then be promptly and easily moved to such new location. Under some circumstances, due to shock, bleeding or the like, it may be advisable to raise one or both ends of the support frame. This can be easily and quickly done by first raising bot-h ends of the support frame if it is in the lowered po-sition, by actuating the foot lever 94 which operates through the linkage and hydraulic pumps 87 and 88 to raise the actuating arms 84 and 85. If one end of the frame should be lowered, the appropriate bypass valve 89 is opened by rotation of the corresponding tube 103, until the proper position is reached. Thereafter, the appropriate tube is manually released and there is no further downward movement of the support frame. In an emergency, a strong attendant can lift the end of the support frame 17, whereupon a bypass valve in the hydraulic cylinder permits the actuating arm to move upwardly and at the same time cause the ow of fluid under the actuating arm to support it in its new position. The connections between the support frame and the actuating arms isv such that they do not create any interference to such upward or downward movement of the support frame 17 If the patient is to be moved from the carriage 16 onto a bed, operating table or some other support, the fifth wheel 60 is preferably released up into its upward position by depressing the lever 69, for the final maneuvering of the carriage into place. Thereafter, the locking mechanism 32 is engaged by counterclockwise movement of the handle bar 59 from its FIGURE 2 position into its FIGURE 11 position. Thereafter, the fifth wheel 60 may be lowered again into its FIGURE 14 position to further prevent sideward movement of the wheeled carriage 10 away from said support from which the patient is being transferred.
In the event that the patient is to be treated, or operated upon while on the wheeled carriage 10, the fifth wheel 60 will normally be placed in its upward retracted position and the locking mechanism 32 will be actuated to prevent movement of the casters, and to lock their wheels against rotation.
Although a particular preferred embodiment of the invention has been disclosed above in detail for illustrative purposes, it will be understood that variations or modifications of such disclosure, which come within the scope ofthe appended claims, are fully contemplated.
What is claimed is:
1. A vwheeled carriage for supporting a patient ina substantially horizontal position, comprising:
an undercarriage having four castered wheels substantially arranged in a rectangle for engagement with a flat supporting surface;
a fifth wheel mounted upon said undercarriage for movement into and out of engagement with said supporting surface;
a substantially flat and rectangular frame;
a pair of spaced, fluid pressure actuated means mounted upon said undercarriage and connected to said frame for supporting said frame in a position substantially parallel with said undercarriage;
operating means for energizing said fluid pressure actuated means to move said frame upwardly with respect to said undercarriage;
control means for de-energizing said pressure fluid actuated means, wherebyrsaid frame can be lowered; and
an elongated and substantially flat patient support means mountable on said rectangular frame.
2. A wheeled carriage for supporting a patient in a substantially horizontal position, comprising:
a substantially rectangular undercarriage having a pair of spaced, upright pressure cylinders mounted thereon near opposite ends thereof, said cylinders having upwardly extendable pistons;
four castered wheels connected to said undercarriage near the four corners thereof for substantially simultaneous engagement with a flat surface defining a plane;
a fifth wheel supported upon said undercarriage in the central portion thereof for rotation around a horizontal axis substantially perpendicular to a line connecting said pressure cylinders, said fifth wheel being movable with respect to said undercarriage between a first position spaced above said plane and a second position in which said fifth wheel extends slightly below said plane;
means resiliently urging said fifth wheel into said first position and means for releasably holding said fifth wheel in said second position;
' a substantially rectangular frame pivotally secured to the upper ends of said pistons for movement thereby into and out of a substantially horizontal position;
actuating means for operating said pressure cylinders to raise said frame;
manually operable control means for separately deactivating said pressure cylinders, whereby said pistons can be lowered simultaneously and independently;
releasable wheel lock means mounted upon said undercarriage fo-r simultaneously engaging Said caster wheels to oppose rotational and pivotal movement thereof; and
an elongated, substantially rectangular and flat patient support removably mounted upon said frame.
3. A device according to claim 2 wherein said frame has a pair of spaced and parallel side members;
and including a pair of side rails pivotally and respectively supported upon said side members for pivotal movement around said side members; and
cooperating lock means on said side members and said side rails for releasably holding said side rails against said pivotal movement and in selected positions with respect to said frame, said lock means being released by urging said side rails lengthwise of said side members, and resilient means resisting such lengthwise movement of said side rails.
4. A device according to claim 2 wherein said undercarriage includes an I-shaped base having a pair of parallel end elements, and the castered wheels are mounted at the ends of said end elements;
wherein said wheel lock means includes a pair of parallel crossbars extending between the castered wheels and beneath the end elements of said base;
resilient means supporting said crossbars on said base and yieldably resisting movement of said crossbars away from said end elements;
a pair of substantially coplanar rings secured to the opposite ends of said crossbars and encircling the casters above the castered wheels, said rings being movable with said crossbar into engagement with said castered wheels to prevent pivotal and rotational movement of said castered wheels; and
cooperating means on said crossbars and said base including a lever pivotally supported upon said base for simultaneously urging said crossbars downwardly from said base so that said castered wheels are engaged by said rings.
5. A device according to claim 2 wherein the axle of the fifth wheel passes through and slightly beyond bottom dead center when said fifth wheel is moved into its second position; and
5 duit means connecting each of said pumps to the lower end of one of said pressure cylinders;
relief valve means associated with said conduit means;
wherein said manually operable control means is connected to said relief valve means for opening same.
References Cited by the Examiner UNITED STATES PATENTS 6/1952 Menzies 5-328 3,217,340 11/1965 Durr 5-83 BENJAMIN HERSH, Primary Examiner.
20 P. GOODMAN, Assistant Examiner.