Patent Publication Number: US-11638620-B2

Title: Steering assembly for surgical robot

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/793,076, filed Feb. 18, 2020, which is a continuation of U.S. patent application Ser. No. 15/256,273, filed Sep. 2, 2016, which claims the benefit of and priority to U.S. Provisional Patent Application No. 62/214,696, filed Sep. 4, 2015, and U.S. Provisional Patent Application No. 62/214,718, filed Sep. 4, 2015, all of which are hereby incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     The present invention relates generally to the field of carts for transportation of a robotic device and stability of the robotic device when in use. 
     Medical device carts may be used to transport a robotic device from one location to another. Traditional medical device carts have four wheels, two fixed front wheels and rear swiveling casters, which may provide adequate maneuverability during general transport, however maneuverability in an operating room has different needs. Space in the operating room is limited which makes navigating the cart around the operating room and into the proper position challenging. When pushing from a rear of the cart, controlling the direction of travel is challenging because of the leverage required to direct the front wheels. The cart has to be backed up, pivoted, and moved back in. Sometimes this has to be repeated several times until the position of the cart is correct. Sometimes, this requires handling the cart from a front end which may be in a sterile field of the operating room, which is not ideal. Further, during transport, the cart may encounter various uneven surfaces (e.g., ramps, inclines, etc.) that may increase the loading on an individual wheel of the cart and potentially cause a rocking or fluttering condition. 
     SUMMARY 
     According to one exemplary embodiment, a portable surgical robot includes a surgical device and a cart. The surgical device is coupled to the cart. The cart includes a chassis, a mount coupled to the chassis, a carriage pivotally coupled to the mount, and a set of wheels. The carriage includes a first bracket positioned at a first lateral end thereof and a second bracket positioned at a second lateral end thereof. A first wheel of the set of wheels is coupled to the first bracket and a second wheel of the set of wheels is coupled to the second bracket. The carriage is configured to pivot relative to the mount to prevent at least one of (i) rocking of the portable surgical robot, (ii) fluttering of the first wheel, (iii) fluttering of the second wheel, and (iv) tipping of the portable surgical robot. 
     According to another exemplary embodiment, a portable cart includes a chassis, a first wheeled mechanism coupled to a front portion of the chassis, and a second wheeled mechanism pivotably coupled to a rear portion of the chassis. The first wheeled mechanism and the second wheel mechanism facilitate maneuvering the portable cart. The second wheeled mechanism is configured to rotate relative to the chassis to prevent at least one of (i) rocking of the portable cart, (ii) fluttering of the first wheeled mechanism, (iii) fluttering of the second wheeled mechanism, and (iv) tipping of the portable cart. 
     According to still another exemplary embodiment, a pivoting carriage for a cart includes a mount, a pivoting member, and a set of wheels. The mount has a housing that defines an internal cavity and a pivot aperture. The mount is configured to couple to a chassis of the cart. The pivoting member is disposed within the internal cavity of the housing. The pivoting member includes a body having a first lateral end and a second lateral end, a first bracket positioned at the first lateral end of the body, a second bracket positioned at the second lateral end of the body, and a rod extending from the body. The rod is positioned to engage the pivot aperture of the housing to thereby pivotally couple the pivoting member to the mount such that the pivoting member is pivotally coupled to the chassis of the cart. The set of wheels includes a first wheel coupled to the first bracket and a second wheel coupled to the second bracket. 
     According to yet another exemplary embodiment, a pivoting carriage for a cart includes a frame member, a set of wheels, and a mount. The frame member includes a first bracket positioned at a first lateral end of thereof and a second bracket positioned at a second lateral end thereof. A first wheel is coupled to the first bracket and a second wheel is coupled to the second bracket. The mount is pivotably coupled to the frame member. The mount is configured to couple the pivoting carriage to a chassis of the cart. The frame member includes a pair of plates spaced a distance apart defining a cavity. The cavity is configured to receive the mount and facilitate rotation of the carriage relative to the mount. 
     Alternative exemplary embodiments relate to other features and combinations of features as may be generally recited in the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The disclosure will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements, in which: 
         FIG.  1    is a front perspective view of a surgical cart, according to an exemplary embodiment; 
         FIG.  2    is a left rear perspective view of the surgical cart of  FIG.  1   ; 
         FIG.  3    is a right rear perspective view of the surgical cart of  FIG.  1   ; 
         FIGS.  4 A- 4 D  are various views of a pivoting carriage assembly of the surgical cart of  FIGS.  1 - 3   , according to an exemplary embodiment; 
         FIG.  5 A  is a perspective view of a chassis of the surgical cart of  FIGS.  1 - 3    with a locking mechanism in a transport configuration, according to an exemplary embodiment; 
         FIG.  5 B  is a perspective view of a chassis of the surgical cart of  FIGS.  1 - 3    with a locking mechanism in a braked configuration, according to an exemplary embodiment; 
         FIGS.  5 C- 5 F  are various cross-sectional views of a locking mechanism being reconfigured between a transport configuration and a braked configuration, according to an exemplary embodiment; 
         FIG.  5 G  is a top plan view of the surgical cart of  FIGS.  1 - 3    with a locking mechanism in a braked configuration, according to an exemplary embodiment; 
         FIG.  6    is a perspective view of a steering assembly of the surgical cart of  FIG.  1   , according to an exemplary embodiment; 
         FIGS.  7 A- 7 B  are various views of the steering assembly of the surgical cart of  FIG.  6    in a first configuration, according to an exemplary embodiment; 
         FIGS.  8 A- 8 B  are various views of the steering assembly of the surgical cart of  FIG.  6    in a second configuration, according to an exemplary embodiment; 
         FIGS.  9 A- 9 B  are various views of the steering assembly of the surgical cart of  FIG.  6    in a third configuration, according to an exemplary embodiment; 
         FIG.  10    is a rear perspective view of a surgical cart, according to another exemplary embodiment; 
         FIG.  11    is a perspective view of a chassis of the surgical cart of  FIG.  10   , according to an exemplary embodiment; 
         FIGS.  12 A- 12 C  are various views of a pivoting carriage assembly of the surgical cart of  FIG.  10   , according to an exemplary embodiment; 
         FIGS.  13 - 14 B  are various perspective views of a steering assembly of the surgical cart of  FIG.  10   , according to an exemplary embodiment; 
         FIGS.  15 A- 15 B  are various views of the steering assembly of the surgical cart of  FIG.  10    in a first configuration, according to an exemplary embodiment; 
         FIGS.  16 A- 16 B  are various views of the steering assembly of the surgical cart of  FIG.  10    in a second configuration, according to an exemplary embodiment; and 
         FIGS.  17 A- 17 B  are various views of the steering assembly of the surgical cart of  FIG.  10    in a third configuration, according to an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Before turning to the figures, which illustrate the exemplary embodiments in detail, it should be understood that the application is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology is for the purpose of description only and should not be regarded as limiting. 
     The portable surgical cart described herein may be used in any context to maneuver and/or relocate a surgical device. The portable surgical cart may also include various features to aid in the stability of the cart during relocation (e.g., on ramps, uneven ground, over door frames, etc.) and during use of a surgical device (e.g., during an operation on a patient, during use of an articulating arm, etc.). In one embodiment, the portable surgical cart includes a steering assembly that facilitates moving the cart in any of a forward direction, a backward direction, a turning direction, a lateral direction, and a rotational direction. In some embodiments, the portable surgical cart includes a pivoting carriage assembly configured to self-adjust on uneven surfaces to increase stability of the portable surgical cart when stationary and/or in transit. In some embodiments, the portable surgical cart includes a locking mechanism configured to provide a support for the portable surgical cart when stationary to allow for precise and stable use of a surgical device of the portable surgical cart. 
     According to the exemplary embodiment shown in  FIGS.  1 - 17 B , a portable cart system, shown as surgical cart  10 , includes a body  20 ; a chassis  100 ; a first wheeled mechanism, shown as wheel steering assembly  200 , disposed at a front end  12  of the surgical cart  10 ; a second wheeled mechanism, shown as pivoting carriage assembly  300 , disposed at a rear end  14  of the surgical cart  10 ; and a locking mechanism, shown as floor lock  400 , disposed at the rear end  14  of the surgical cart  10 . 
     As shown in  FIGS.  1 - 3  and  10   , the body  20  of the surgical cart  10  is coupled to the chassis  100 . According to an exemplary embodiment, the body  20  is removably coupled to the chassis  100  (e.g., fastened, etc.). In an alternative embodiment, the body  20  is fixed to the chassis  100 . For example, the body  20  and the chassis  100  may be welded or glued to one another during construction of the surgical cart  10 . In another example, the body  20  and the chassis  100  may be a single, unitary structure. The wheel steering assembly  200  includes a pair of wheels, shown as front wheels  202 , and the pivoting carriage assembly  300  includes a pair of caster wheels, shown as rear casters  302 . The front wheels  202  and the rear casters  302  facilitate moving the surgical cart  10 . According to an exemplary embodiment, the surgical cart  10  is configured to transport a surgical robotic device. In other embodiments, the cart is configured to transport a camera, a computer, a monitor, and/or any other device or component that may be used during a surgical procedure or medical monitoring. In alternative embodiments, the cart is configured for use as a guidance cart. 
     As shown in  FIGS.  1 - 3  and  10   , the body  20  of the surgical cart  10  may include a robotic device, shown as surgical device  30 , a computing system  40 , and a handle assembly  50 . In some embodiments, the surgical cart  10  does not include the surgical device  30 . For example, the surgical cart  10  may be a guidance cart and/or still another type of cart (e.g., a cart configured to transport a camera, a computer, a monitor, and/or any other device or component that may be used during a surgical procedure or medical monitoring, etc.). In one embodiment, the body  20  also includes various compartments (e.g., cabinets, drawers, etc.) configured to store various objects used in operation of the surgical cart  10  (e.g., surgical tools, etc.). As shown in  FIGS.  1 - 3   , the surgical device  30  is coupled (e.g., fastened, etc.) to a mounting location  22  defined by the body  20 . The surgical device  30  may be any suitable mechanical or electromechanical structure. According to an exemplary embodiment, the surgical device  30  is an articulating arm (e.g., having three or more degrees of freedom or axes of movement, etc.). The computing system  40  may include various hardware components and software for operation and control of the surgical device  30 . The computing system  40  may be any known computing system but is preferably a programmable, processor-based system. For example, the computing system  40  may include a microprocessor, a hard drive, random access memory (RAM), read only memory (ROM), input/output (I/O) circuitry, and any other well-known computer component. The computing system  40  is may be adapted for use with various types of storage devices (persistent and removable), such as, for example, a portable drive, magnetic storage (e.g., a floppy disk, etc.), solid state storage (e.g., a flash memory card, etc.), optical storage (e.g., a compact disc, etc.), and/or network/Internet storage. 
     The computing system  40  may be communicably coupled to the surgical device  30  via any suitable wired or wireless communication protocol (i.e., a physical interface). A physical interface may be any known interface such as, for example, a wired interface (e.g., serial, USB, Ethernet, CAN bus, and/or other cable communication interface) and/or a wireless interface (e.g., wireless Ethernet, wireless serial, infrared, and/or other wireless communication system). A software interface may enable the computing system  40  to communicate with and control operation of the surgical device  30 . In one embodiment, the software interface includes a utility that allows the computing system  40  to issue commands to the surgical device  30 . For example, the computing system  40  may provide a command to enter the surgical device into a specific mode (e.g., an autonomous mode, a haptic mode, a free mode, etc.). The computing system  40  may be adapted to enable the surgical device  30  to perform various functions related to surgical planning, navigation, image guidance, and/or haptic guidance. For example, the computing system  40  may include algorithms, programming, and software utilities related to general operation, data storage and retrieval, computer aided surgery (CAS), applications, haptic control, and/or any other suitable functionality. 
     In one embodiment, the surgical device  30  is configured as an autonomous surgical robotic system controlled by the computing system  40  to move a surgical tool to perform a procedure on a patient (e.g., for orthopedic joint replacement, to perform bone cutting autonomously with a high speed burr, etc.). In other embodiments, the surgical device  30  is a haptic device configured to be manipulated by a user to move a surgical tool to perform a procedure on a patient. For example, during a procedure, the computing system  40  may implement control parameters for controlling the surgical device  30  based on a relationship between an anatomy of the patient and a position, an orientation, a velocity, and/or an acceleration of a portion of the surgical device  30  (e.g., a surgical tool, etc.). In one embodiment, the surgical device  30  is controlled to provide a limit on user manipulation of the device (e.g., by limiting the user&#39;s ability to physically manipulate the surgical device  30 , etc.). In another embodiment, the surgical device  30  is controlled to provide haptic guidance (i.e., tactile and/or force feedback) to the user. “Haptic” refers to a sense of touch, and the field of haptics involves research relating to human interactive devices that provide tactile and/or force feedback to an operator. Tactile feedback generally includes tactile sensations such as, for example, vibration, whereas force feedback refers to feedback in the form of force (e.g., resistance to movement, etc.) and/or torque (also known as “wrench). Wrench may include feedback in the form of a force, a torque, or a combination of a force and a torque. 
     In orthopedic applications, for example, the surgical device  30  can be applied to the problems of inaccuracy, unpredictability, and non-repeatability in bone preparation by assisting the surgeon with proper sculpting of bone to thereby enable precise, repeatable bone resections while maintaining intimate involvement of the surgeon in the bone preparation process. Moreover, because the surgical device  30  may haptically guide the surgeon in the bone cutting operation or autonomously perform the operation, the skill level of the surgeon is less critical. As a result, surgeons with varying degrees of skill and experience are able to perform accurate, repeatable procedures. 
     As shown in  FIGS.  1 - 3   , the surgical cart  10  includes a display device  42  and an input device  44  disposed on the body  20  at the rear end  14  of the surgical cart  10 . In an alternative embodiment, the display device  42  and/or the input device  44  are otherwise positioned on the surgical cart  10  or remote from the surgical cart  10  (e.g., mounted on a wall of an operating room or other location suitable for viewing by the user, etc.). The display device  42  is configured as a visual interface between the computing system  40  and the user. The display device  42  may be communicably coupled to the computing system  40  and may be any device suitable for displaying text, images, graphics, and/or other visual output. For example, the display device  42  may include a standard display screen (e.g., LED, LCD, CRT, plasma, etc.), a touch screen, a wearable display (e.g., eyewear such as glasses or goggles), a projection display, a head-mounted display, a holographic display, and/or any other visual output device. The display device  42  may be used to display any information useful for a medical procedure, such as, for example, images of anatomy generated from an image data set obtained using conventional imaging techniques, graphical models (e.g., CAD models of implants, instruments, anatomy, etc.), graphical representations of a tracked object (e.g., anatomy, tools, implants, etc.), digital or video images, registration information, calibration information, patient data, user data, measurement data, software menus, selection buttons, status information, and/or the like. The input device  44  may enable the user of the surgical cart  10  to communicate with the surgical device  30  and/or other components of the surgical cart  10  (e.g., the wheel steering assembly  200 , the floor lock  400 , etc.). The input device  44  may be communicably coupled to the computing system  40  and may include any device configured to enable a user to provide input the surgical cart  10 . For example, the input device  44  may be, but not limited to, a keyboard, a mouse, a trackball, a touch screen, a touch pad, voice recognition hardware, dials, switches, buttons, a trackable probe, a foot pedal, a remote control device, a scanner, a camera, a microphone, a joystick, and/or the like. In some embodiments, the surgical cart  10  supplements or replaces direct visualization of a surgical site, enhances a surgeon&#39;s natural tactile sense and physical dexterity, and facilitates the targeting, repairing, and replacing of various structures in the body. 
     Referring to  FIGS.  1 - 3  and  10   , the handle assembly  50  may increase portability and maneuverability of the surgical cart  10 . As shown in  FIGS.  1 - 3  and  10   , the handle assembly  50  is positioned at the rear end  14  of the surgical cart  10  and, in the embodiment shown, includes a pair of handles, shown as handgrips  52 , and a handrail  54 . The handgrips  52  and/or the handrail  54  may facilitate maneuvering the surgical cart  10  in at least one of a forward direction, a rearward direction, a lateral direction (i.e., a sideways direction), and a rotational direction. In alternative embodiments, the surgical cart  10  includes additional handles and/or handrails positioned around the body  20 . In one embodiment, the handle assembly  50  includes a single, continuous structure that extends around the entire periphery of surgical cart  10  to provide 360 degree handhold access for ease of maneuverability of the surgical cart  10 . In other embodiments, the handle assembly  50  includes a handrail positioned on one or both lateral sides of the surgical cart  10  to facilitate pulling or pushing the surgical cart  10  from the side (e.g., in a lateral direction, forward direction, rearward direction, etc.). In other embodiments, the handle assembly  50  includes a handrail positioned on the front end  12  of the surgical cart  10  to facilitate pulling or pushing the surgical cart  10  from the front end  12 . 
     As shown in  FIGS.  1 - 3 ,  5 A- 5 B, and  10 - 11   , the chassis  100  includes a front portion  110 , a rear portion  120 , and a middle portion  130 . According to an exemplary embodiment, the front portion  110  is coupled to the rear portion  120  via the middle portion  130  to create a single, continuous chassis  100  (i.e., a unitary structure). As shown in  FIGS.  5 A- 5 B and  11   , the front portion  110  and the middle portion  130  of the chassis  100  define an inner volume  112 . The inner volume  112  is configured to receive the wheel steering assembly  200  such that the wheel steering assembly  200  may be coupled to the chassis  100 . The rear portion  120  of the chassis  100  defines a cavity  122 . The cavity  122  is configured to receive the pivoting carriage assembly  300  such that the pivoting carriage assembly  300  may be coupled to the chassis  100 . 
     As shown in  FIGS.  4 A- 4 D , the pivoting carriage assembly  300  includes a frame member, shown as pivoting carriage  310 . The pivoting carriage  310  includes a pair of brackets, shown as caster brackets  312 . The caster brackets  312  are configured to couple the rear casters  302  to the pivoting carriage  310 . The rear casters  302  include an extension, shown as stem  304 , that extends from a top portion thereof. The caster brackets  312  are configured to receive the stems  304  of the rear casters  302  to rotationally couple the rear casters  302  to the pivoting carriage  310 . In an alternative embodiment, the pivoting carriage  310  defines a flat mounting location and the rear casters  302  include a corresponding flat mounting plate configured to be fastened to the flat mounting location to couple the rear casters  302  to the pivoting carriage  310 . According to an exemplary embodiment, the rear casters  302  are rotationally coupled to the pivoting carriage  310  such that the rear casters  302  are free to rotate about a central axis thereof, shown as vertical axis  340 . Thus, the rear casters  302  may freely rotate about vertical axis  340  as the surgical cart  10  is maneuvered. In some embodiments, the rear casters  302  include a brake to prevent rotation of wheels of the rear casters  302  (i.e., aid in locking the surgical cart  10  in place) and/or rotationally fix the rear casters  302  in a desired direction (i.e., prevent rotation about the vertical axis  340 ). In an alternative embodiment, the rear casters  302  are rotationally fixed relative to the vertical axis  340  such that they are oriented in a single direction (e.g., forward, etc.). 
     Referring still to  FIGS.  4 A- 4 D , the pivoting carriage assembly  300  includes a mounting portion, shown as carriage mount  320 . According to an exemplary embodiment, the carriage mount  320  is configured to pivotably couple the pivoting carriage assembly  300  to the rear portion  120  of the chassis  100 . As shown in  FIGS.  4 A- 4 D , the carriage mount  320  includes a top surface, shown as mounting surface  322 , and side surfaces, shown as interaction surfaces  328 . According to the exemplary embodiment shown in  FIGS.  4 A- 4 D , the carriage mount  320  defines a plurality of apertures, shown as apertures  325 , configured to receive a corresponding plurality of fasteners, shown as fasteners  326 , that extend from the mounting surface  322 . In an alternative embodiment, the fasteners  326  are integrally formed along the mounting surface  322  of the carriage mount  320 . 
     Referring back to  FIGS.  5 A- 5 B , the rear portion  120  of the chassis  100  includes a plate, shown as mounting plate  124 . The mounting plate  124  defines a plurality of apertures, shown as apertures  126 . The apertures  126  are positioned to correspond with the fasteners  326  of the carriage mount  320  to facilitate coupling the pivoting carriage assembly  300  to the chassis  100 . According to an exemplary embodiment, the pivoting carriage assembly  300  is recessed within the cavity  122  such that the mounting surface  322  of the carriage mount  320  abuts a bottom surface of mounting plate  124 . In one embodiment, the apertures  126  are threaded such that an additional corresponding fastener (e.g., nut, etc.) is not needed when the apertures  126  receive the fasteners  326  (e.g., bolts, etc.). In other embodiments, the fasteners  326  extend through the apertures  126  and receive corresponding fasteners (e.g., nuts, etc.) to couple the pivoting carriage assembly  300  to the chassis  100 . In still another embodiment, fasteners (e.g., nuts, etc.) are fixed (e.g., welded, glued, integrally formed, etc.) to the mounting plate  124 , positioned to align with the apertures  126  and receive the fasteners  326 . 
     Referring back to  FIGS.  4 A- 4 D , the pivoting carriage  310  defines a pair of apertures, shown as apertures  314 . The apertures  314  are configured to receive a rod, shown as pivoting rod  324 , that extends from each longitudinal end of the carriage mount  320 , thereby pivotably coupling the carriage mount  320  and the pivoting carriage  310 . The interaction between the apertures  314  and the pivoting rod  324  facilitates the rotation of the pivoting carriage  310  about a longitudinal axis, shown as longitudinal axis  330 . In some embodiments, the rotation of the pivoting carriage  310  about the longitudinal axis  330  is aided by a lubricant and/or a bearing disposed between the apertures  314  and the pivoting rod  324 . 
     As shown in  FIGS.  4 A- 4 D , the pivoting carriage  310  includes a pair of plates, shown as plates  316 , disposed on each lateral side of the carriage mount  320 . The plates  316  are spaced a distance apart to define a cavity, shown as pivoting gap  318 . The pivoting gap  318  is configured to receive the carriage mount  320  when the carriage mount  320  is coupled to the pivoting carriage  310  (e.g., rotationally coupled via the pivoting rod  324 , etc.). According to an exemplary embodiment, the pivoting gap  318  is sized to facilitate the rotation of the pivoting carriage  310  relative to the carriage mount  320 . 
     As shown in  FIGS.  4 A- 4 C , the pivoting carriage assembly  300  includes a limiting member, shown as rotational stop  350 , positioned on each lateral side of the pivoting carriage  310 . In other embodiments, the pivoting carriage assembly  300  includes a different number of rotational stops  350  on each lateral side of the pivoting carriage  310  (e.g., two, three, etc.). As shown in  FIGS.  4 A- 4 C , the rotational stops  350  are disposed along the plates  316 . In one embodiment, the rotational stops  350  are coupled to the plates  316  (e.g., welded, glued, fastened, etc.). In an alternative embodiment, the rotational stops  350  and the plates  316  form a single, continuous structure (e.g., a unitary structure, etc.). 
     According to an exemplary embodiment, the rotational stops  350  are configured to limit the amount of rotation of the pivoting carriage  310  relative to the carriage mount  320 . By way of example, one of the rotational stops  350  may contact a corresponding surface (e.g., a plate, etc.) of the rear portion  120  of the chassis  100  when the pivoting carriage  310  reaches a pivoting travel limit (e.g., rotate two degrees about the longitudinal axis  330 , etc.). According to an exemplary embodiment, the rotational stops  350  are sized to allow the pivoting carriage  310  to rotate about the longitudinal axis  330  to the pivoting travel limit which corresponds to a vertical displacement of at least one of the rear casters  302  of approximately plus or minus 6 millimeters (mm) (e.g., a first caster  302  displaces upward a distance and a second caster  302  displaces downward the same distance, etc.). In other embodiments, the rotational stops  350  are differently sized to allow the pivoting carriage  310  to rotate about the longitudinal axis  330  to a different pivoting travel limit (e.g., rotate one degree, rotate three degrees, etc.) which corresponds to a vertical displacement of at least one of the rear casters  302  of less than or greater than plus or minus 6 mm (e.g., 4 mm, 8 mm, etc.). In some embodiments, the rear casters  302  include a spring member to allow for additional or alternative vertical displacement to that provided by the pivoting carriage assembly  300 . 
     In an alternative embodiment, the carriage mount  320  is laterally offset from the longitudinal axis  330  (e.g., towards one of the rear casters  302 , etc.). Laterally offsetting the carriage mount  320  may facilitate vertically displacing one of the rear caster  302  a different distance than the other rear caster  302  (e.g., one may displace a first distance in one direction and the other may displace a different distance in an opposing second direction, etc.). This configuration may be advantageous if the majority of the weight supported by the surgical cart  10  is positioned towards one of the sides of the surgical cart  10 . In yet another alternative embodiment, the carriage mount  320  is omitted and replaced by a central support structure configured to slidably receive a curved beam member. The curved beam member may be configured to slidably translate through the central support as the surgical cart  10  encounters various uneven surfaces causing the rear casters  302  to vertically displace. In still another alternative embodiment, the pivoting carriage assembly  300  includes a lateral plate that defines symmetrically angled slots positioned on each lateral side of the lateral plate. According to an exemplary embodiment, the symmetrically angled slots are configured to receive and engage with pins. The engagement of the pins with the symmetrically angled slots facilitates the rotation of the pivoting carriage assembly  300  about a central axis thereof defined between the symmetrically angled slots. 
     According to an alternative embodiment, the rotational stops  350  are omitted and the plates  316  are configured to limit an amount of rotation of the pivoting carriage  310  relative to the carriage mount  320 . The rotation of the pivoting carriage  310  may be limited by an interaction between the interaction surfaces  328  of the carriage mount  320  and the plates  316 . By way of example, the width of pivoting gap  318  (i.e., based on the spacing between the plates  316 , the distance between the plate  316  and the interaction surface  328 ) may define the amount of rotation of the pivoting carriage  310  relative to the carriage mount  320  (e.g., prior to all of the load from the surgical cart  10  being transferred through a single rear caster  302 , etc.). For example, the larger the width of the pivoting gap  318 , a greater amount of rotation of the pivoting carriage  310  relative to the carriage mount  320  is allowed. Conversely, the smaller the width of the pivoting gap  318 , a lesser amount of rotation of the pivoting carriage  310  relative to the carriage mount  320  is allowed. 
     As shown in  FIG.  12 B , the pivoting carriage assembly  300  includes a frame member, shown as pivoting carriage  360  (e.g., a pivoting bogie, etc.). The pivoting carriage  360  includes a main portion, shown as body  362 , having a pair of brackets, shown as caster brackets  364 , with one positioned at each lateral end of the body  362 . The caster brackets  364  are configured to couple the rear casters  302  to the pivoting carriage  360 . The caster brackets  364  are configured to receive the stems  304  of the rear casters  302  to rotationally couple the rear casters  302  to the pivoting carriage  360 . In an alternative embodiment, the pivoting carriage  360  defines a flat mounting location and the rear casters  302  include a corresponding flat mounting plate configured to be fastened to the flat mounting location to couple the rear casters  302  to the pivoting carriage  360 . According to an exemplary embodiment, the rear casters  302  are rotationally coupled to the pivoting carriage  360  such that the rear casters  302  are free to rotate about the vertical axis  340  thereof. Thus, the rear casters  302  may freely rotate about vertical axis  340  as the surgical cart  10  is maneuvered. In some embodiments, the rear casters  302  include a brake to prevent rotation of wheels of the rear casters  302  (i.e., aid in locking the surgical cart  10  in place) and/or rotationally fix the rear casters  302  in a desired direction (i.e., prevent rotation about the vertical axis  340 ). In an alternative embodiment, the rear casters  302  are rotationally fixed relative to the vertical axis  340  such that they are oriented in a single direction (e.g., forward, etc.). 
     As shown in  FIGS.  12 A- 12 C , the pivoting carriage assembly  300  includes a mounting portion, shown as carriage mount  370 . According to an exemplary embodiment, the carriage mount  370  is configured to pivotably couple the pivoting carriage assembly  300  to the rear portion  120  of the chassis  100 . As shown in  FIGS.  12 A- 12 C , the carriage mount  370  includes a body, shown as housing  372 . As shown in  FIG.  12 C , the housing  372  of the carriage mount  370  defines an internal cavity, shown as carriage cavity  374 . According to an exemplary embodiment, the carriage cavity  374  is configured to receive the pivoting carriage  360 . 
     As shown in  FIGS.  12 A- 12 B , the pivoting carriage  360  includes a rod, shown as pivoting rod  366 , that extends from the front and rear of the body  362  of the pivoting carriage  360 . As shown in  FIGS.  12 A- 12 C , the housing  372  of the carriage mount  370  defines a pair of apertures, shown as pivot apertures  376 . As shown in  FIG.  12 A , the pivot apertures  376  are configured to receive the pivoting rod  366 , thereby pivotably coupling the pivoting carriage  360  to the carriage mount  370 . The interaction between the pivot apertures  376  and the pivoting rod  366  facilitates the rotation of the pivoting carriage  360  about a longitudinal axis, shown as longitudinal axis  390 . In some embodiments, the rotation of the pivoting carriage  360  about the longitudinal axis  390  is aided by a lubricant and/or a bearing disposed between the pivot apertures  376  and the pivoting rod  366 . 
     As shown in  FIGS.  11  and  12 A- 12 C , the housing  372  of the carriage mount  370  defines a plurality of apertures, shown as mounting apertures  378 . As shown in  FIG.  11   , the mounting apertures  378  are configured to receive a plurality of fasteners (e.g., bolts, etc.), shown as fasteners  384 , to thereby couple the pivoting carriage assembly  300  (e.g., the pivoting carriage  360 , the carriage mount  370 , etc.) to the rear portion  120  of the chassis  100 . 
     As shown in  FIG.  12 C , the pivoting carriage assembly  300  includes a limiting member, shown as rotational stop  382 , positioned within the carriage cavity  374  of the housing  372  (e.g., disposed along an inner surface of a top portion of the housing  372 , etc.), at each longitudinal end of the carriage mount  370 . In other embodiments, the pivoting carriage assembly  300  includes a different number of rotational stops  382  positioned on each lateral side of the pivoting carriage  310  (e.g., two, three, etc.). In some embodiments, the rotational stops  382  are coupled to the housing  372  (e.g., welded, glued, fastened, etc.). In some embodiments, the rotational stops  382  and the housing  372  form a single, continuous structure (e.g., a unitary structure, etc.). In an alternative embodiment, the rotational stops  382  are additionally or alternatively positioned on and/or coupled to the body  362  of the pivoting carriage  360 . 
     According to an exemplary embodiment, the rotational stops  382  are positioned to limit the amount of rotation of the pivoting carriage  360  relative to the carriage mount  370 . By way of example, one of the rotational stops  382  may contact a corresponding surface (e.g., a top surface, etc.) of the body  362  when the pivoting carriage  360  reaches a pivoting travel limit (e.g., rotates two degrees about the longitudinal axis  390 , etc.). According to an exemplary embodiment, the rotational stops  382  are sized to allow the pivoting carriage  360  to rotate about the longitudinal axis  390  to the pivoting travel limit which corresponds to a vertical displacement of at least one of the rear casters  302  of approximately plus or minus 6 millimeters (mm) (e.g., a first caster  302  displaces upward a distance and a second caster  302  displaces downward the same distance, etc.). In other embodiments, the rotational stops  382  are differently sized to allow the pivoting carriage  360  to rotate about the longitudinal axis  390  to a different pivoting travel limit (e.g., rotate one degree, rotate three degrees, etc.) which corresponds to a vertical displacement of at least one of the rear casters  302  of less than or greater than plus or minus 6 mm (e.g., 4 mm, 8 mm, etc.). In some embodiments, the rear casters  302  include a spring member to allow for additional or alternative vertical displacement to that provided by the pivoting carriage assembly  300 . As shown in  FIGS.  12 A- 12 C , the housing  372  of the carriage mount  370  defines an aperture, shown as aperture  380 , positioned at each end of the housing  372 . According to an exemplary embodiment, the apertures  380  are positioned to prevent the caster brackets  364  and/or the stems  304  from engaging the housing  372  when the pivoting carriage  360  pivots about the longitudinal axis  390  (e.g., when the pivoting travel limit is reached, etc.). 
     According to an exemplary embodiment, the pivoting carriage assembly  300  and the front wheels  202  provide a quasi-four-point support for the surgical cart  10  during transport and/or when stationary. For example, the pivoting ability of the pivoting carriage  310  and/or the pivoting carriage  360  configures the surgical cart  10  to function as a three-wheeled cart (e.g., all of the loading is transferred to the chassis  100  through the carriage mount  320  or the carriage mount  370 , etc.) when the pivoting travel limit is not reached and into a four-wheeled cart when the pivoting travel limit is reached (e.g., the rotational stops  350  or the rotational stops  382  limit the rotation, etc.). Thus, the front wheels  202  and the pivoting carriage assembly  300  provide a deterministic three-point support for the surgical cart  10  (e.g., functions as a three-wheeled cart when the pivoting travel is not reached, etc.) for increased rocking resistance and caster fluttering resistance (e.g., relative to a traditional four-wheeled cart, etc.) and four-point support (e.g., functions as a four-wheeled cart when the pivoting travel is reached, etc.) for increased stability (e.g., improved tipping resistance, relative to a traditional three-wheeled cart, etc.). 
     According to an exemplary embodiment, the pivoting carriage assembly  300  facilitates the self-adjustment of the surgical cart  10  while moving and/or stationary on an uneven surface (e.g., ramps, over door sills, over cords, into an elevator, etc.) to provide the three-point support. Traditional surgical carts with four-point support may lean when encountering an uneven surface, transferring a greater amount of load to one side of the cart causing an increased risk for rocking of the cart or fluttering of a caster wheel. According to an exemplary embodiment, the rotation of the pivoting carriage  310  or the pivoting carriage  360  relative to the carriage mount  320  or the carriage mount  370 , respectively, (i.e., self-adjustment) advantageously prevents rocking of the surgical cart  10 . By way of example, the self-adjustment may prevent transferring all of the loading from the surgical cart  10  onto one of the rear casters  302  (e.g., the load from the surgical cart  10  is transferred to an uneven ground surface substantially through both of the rear casters  302 , etc.), which effectively prevents the surgical cart  10  from rocking and/or one of the front wheels  202  and the rear casters  302  from fluttering. 
     Traditional surgical carts with three-point support (i.e., three-wheeled carts) may have an increased risk of tipping. According to an exemplary embodiment, the pivoting carriage assembly  300  effectively provides a four-point support when the pivoting travel limit is reached to advantageously prevent tipping of the surgical cart  10 . Thus, the pivoting carriage assembly  300  eliminates rocking of the surgical cart  10  and fluttering of the front wheels  202  and the rear casters  302 , while still satisfying various regulatory requirements for tipping (e.g., IEC tipping standards, etc.). 
     Referring now to  FIGS.  2 - 3 ,  5 A- 5 G,  10 - 11 , and  13   , the floor lock  400  is configured to stabilize the surgical cart  10  in place. The floor lock  400  is configured to prevent movement of at least one of the rear end  14  of the surgical cart  10  and the front end  12  of the surgical cart  10  in a lateral and/or a longitudinal direction when actuated (e.g., engaged with a ground surface, etc.). According to the exemplary embodiment shown in  FIGS.  2 - 3 ,  5 A- 5 G,  10 - 11 , and  13   , the floor lock  400  is a mechanical mechanism actuated by an operator of the surgical cart  10 . In an alternative embodiment, the floor lock  400  is an electromechanical mechanism that is actuated by an actuator (e.g., an electric motor, etc.) in response to receiving a command from the computing system  40  (e.g., a command based on an operator input received by the display device  42  or input device  44 , etc.). 
     According to the exemplary embodiment shown in  FIGS.  5 A- 5 F , the floor lock  400  is selectively reconfigurable between a disengaged configuration, shown as transportation configuration  402  (shown in  FIGS.  5 A and  5 C ), and an engaged, shown as machining configuration  406  (shown in  FIGS.  5 B and  5 E ) (e.g., such that the surgical cart  10  is in a machining mode, a park mode, a brake mode, etc.). The floor lock  400  may be actuated from the transportation configuration  402  to the machining configuration  406  in response to an operator of the surgical cart  10  pressing down on a pedal  412 . According to an exemplary embodiment, the floor lock  400  is structured as a latching push-push mechanism that requires a single push to reconfigure the floor lock  400  from the transportation configuration  402  to the machining configuration  406  (e.g., a single push of the pedal  412  immobilizes an approximately 600 pound cart, etc.), and vice versa. Advantageously, the floor lock  400  eliminates the need for a ratcheting mechanism, a pumping mechanism, and/or an actuator (e.g., a hydraulic cylinder, an electric motor, etc.) to immobilize the surgical cart  10  with the floor lock  400  (e.g., the actuation of the floor lock  400  may be relatively easily provided by an operator of the surgical cart  10 , etc.). In an alternative embodiment, the floor lock  400  is configured as a push-pull mechanism such that by pushing on the pedal  412  causes the floor lock  400  to engage a ground surface and lifting on the pedal  412  cause the floor lock  400  to disengage from the ground surface. In yet another alternative embodiment, the floor lock  400  includes a first lever configured to engage the floor lock  400  with a ground surface and a second lever configured to disengage the floor lock  400  from the ground surface. 
     As shown in  FIGS.  5 A- 5 F , the floor lock  400  includes a first member, shown as brake pedal  410 , and a second member, shown as brake  420 . The brake pedal  410  includes an actuation surface, shown as pedal  412 , coupled to a pair of arms, shown as arms  414 . According to an exemplary embodiment, the pedal  412  is foldable (e.g., for storage, to move out of the way, etc.). By way of example, the pedal  412  may be pivotably coupled to the arms  414  with rotational stops that facilitate selectively positioning the pedal  412  between a stowed position and an operational position. The arms  414  may define a slot configured to receive a limiter of the pedal  412 . The slot may define the motion through which the limiter, and thereby the pedal  412 , may travel. As shown in  FIGS.  5 C- 5 F , the arms  414  are rotationally coupled to the chassis  100  via a fastener, shown as hinge  416 . As shown in  FIGS.  5 A- 5 F , the brake  420  includes an arm, shown as brake arm  422 , and a pad, shown as brake pad  424 , coupled to the brake arm  422 . As shown in  FIGS.  5 C- 5 F , the brake arm  422  is rotationally coupled to the chassis  100  via a fastener, shown as hinge  426 . As shown in  FIG.  5 B , the floor lock  400  includes an actuator, shown as brake actuator  430 . The brake actuator  430  may include a gas cylinder, a hydraulic cylinder, a coil spring, or the like. The brake actuator  430  is configured to couple the brake pedal  410  to the brake  420 . 
     As shown in  FIGS.  5 A- 5 F , the floor lock  400  further includes a first lever, shown as latching lever  440 ; a guide block, shown as cam block  450 ; a second lever, shown as extension lever  460 ; and a pair of linkages, shown as lift linkages  470 . In some embodiments, the floor lock  400  includes legs (e.g., one, two, three, etc. legs), shown as front chassis legs  480 , positioned at the front end  12  of the chassis  100 . As shown in  FIGS.  5 C- 5 F , a first end of the latching lever  440  is pivotably coupled to the brake pedal  410  via a fastener, shown as hinge  418 , and an opposing second end of the latching lever  440  is slidably coupled within a slot, shown as cam track  452 , defined by the cam block  450 . The opposing second end of the latching lever  440  may also be coupled to a first end of a second lever, shown as extension lever  460 . An opposing second end of the extension lever  460  is coupled to a first end of the lift linkage  470 . The lift linkage  470  includes a first member, shown as rotational linkage  472 ; a second linkage, shown as guide linkage  474 ; a third linkage, shown as cylinder  476 ; and a fourth linkage, shown as rod  478 . As shown in  FIGS.  5 A- 5 F , the floor lock  400  includes a bracket, shown as bracket  479 . The bracket  479  is configured to couple an opposing second end of the lift linkage  470  to the body  20  of the surgical cart  10 . According to an exemplary embodiment, the lift linkage  470  is configured to facilitate lifting the front wheels  202  such that the front portion  110  of the chassis  100  kneels (i.e., a kneeling feature) until the front chassis legs  480  contact a ground surface  600 . In an alternative embodiment, the lift linkage  470  is configured to facilitate the extension of the front chassis legs  480  such that the front chassis legs  480  lift the front portion  110  of the chassis  100  such that the front wheels  202  no longer engage the ground surface  600 . According to an exemplary embodiment, the lift linkages  470  are or include gas springs. 
     As shown in  FIGS.  5 A and  5 C , the floor lock  400  is configured in the transportation configuration  402 . The brake pad  424  and the front chassis legs  480  do not come into contact with the ground surface  600  in the transportation configuration  402 , facilitating transporting and/or maneuvering the surgical cart  10  freely. As shown in  FIG.  5 D , a user may apply a downward actuation force on the pedal  412 , indicated by directional arrow  490 , such that the arms  414  rotate downward about hinge  416  and reconfigure the floor lock  400  into an intermediate configuration  404  from the transportation configuration  402 . The actuation of the brake pedal  410  causes the brake arm  422  of the brake  420  to rotate about the hinge  426  (e.g., via the brake actuator  430 , etc.) such that the brake pad  424  engages the ground surface  600 . The actuation of the brake pedal  410  to the intermediate configuration  404  further causes the opposing second end of the latching lever  440  to follow along the cam track  452  in a first rotational direction (e.g., counter-clockwise, etc.), which thereby causes the extension lever  460  to extend and engage the rotational linkage  472  such that the rotational linkage  472  rotates. The rotation of the rotational linkage  472  causes the guide linkage  474  and the rod  478  to translate (e.g., vertically upward, etc.) such that the rod  478  slidably translates within the cylinder  476 . According to an exemplary embodiment, the translation of the rod  478  corresponds with a vertical displacement of the front wheels  202  such that the front portion  110  of the chassis  100  lowers (i.e., kneels) until the front chassis legs  480  engage the ground surface  600 . In an alternative embodiment, the translation of the rod  478  corresponds with a vertical displacement of the front chassis legs  480  such that the front portion  110  of the chassis  100  rises until the front wheels  202  disengage from the ground surface  600 . 
     As shown in  FIG.  5 E , the user may stop applying the downward actuation force on the pedal  412  such that the arms  414  rotate upward about the hinge  416 , as indicated by directional arrow  492 , configuring the floor lock  400  into the machining configuration  406 . By releasing the brake pedal  410 , the latching lever  440  proceeds along the cam track  452  around a lip, shown as latching lip  454  (see, e.g.,  FIGS.  5 C- 5 D ). The latching lip  454  holds the latching lever  440  in place such that the floor lock  400  remains in the machining configuration  406  (e.g., without an external force being applied by an operator, etc.). It should be noted that  FIGS.  5 D- 5 E  are separated for illustrative purposes only. In practice, reconfiguring the floor lock  400  of the surgical cart  10  from the transportation configuration  402  to the machining configuration  406  requires a single actuation motion (e.g., pressing down on the pedal  412  and then releasing, etc.). 
     As shown in  FIG.  5 F , a user may apply a downward actuation force on the pedal  412 , indicated by directional arrow  494 , such that the arms  414  rotate downward about hinge  416  and reconfigure the floor lock  400  into a disengagement configuration  408  from the machining configuration  406 . As shown in  FIG.  5 F , applying a downward force onto the pedal  412  when in the machining configuration  406  causes the opposing second end of the latching lever  440  to disengage from the latching lip  454 . The disengagement of the opposing second end of the latching lever  440  from the latching lip  454  allows the latching lever  440  to follow along the cam track  452  in a second rotational direction (e.g., clockwise, etc.) to return the floor lock to the transportation configuration  402 . For example, following the application of the downward force, a user may remove the force from the pedal  412  (e.g., release the pedal  412 , etc.) such that the latching lever  440  moves in the second rotational direction around the cam track  452 . Thus, the brake pedal  410  rotates about the hinge  416  and returns to the position shown in  FIG.  5 C  (i.e., the transportation configuration  402 ), thereby causing the brake  420  to rotate about the hinge  426  such that the brake pad  424  disengages from the ground surface  600 . Further, the extension lever  460  retracts, thereby causing the guide linkage  474  and the rod  478  to translate vertically downward such that the rod  478  slidably translates out from the cylinder  476 . In turn, the front wheels  202  extend downward to engage the ground surface  600 , lifting the front portion  110  of the chassis such that the front chassis legs  480  disengage from the ground surface  600 . 
     As shown in  FIGS.  11  and  13   , the lift linkages  470  (e.g., the cylinder  476  and the rod  478 , etc.) may be replaced with a suspension element, shown as coilover  482 . The coilover  482  includes a shock absorber, shown as shock  484 , and a resilient member, shown as coil spring  486 , encircling the shock  484 . According to an exemplary embodiment, the coilover  482  is configured to provide controlled dampening as the front portion  110  of the chassis  100  kneels and lifts. In other embodiments, the floor lock  400  includes a plurality of coilovers  482  (e.g., two, three, etc.). 
     According to an exemplary embodiment, the engagement of the brake pad  424  with the ground surface  600  substantially prevents movement of the rear end  14  of the surgical cart  10  (e.g., in a lateral and a longitudinal direction, etc.) and the engagement of the front chassis legs  480  with the ground surface  600  substantially prevents movement of the front end  12  of the surgical cart  10  (e.g., in a lateral and a longitudinal direction, etc.), thereby establishing complete immobility of the surgical cart  10  (e.g., without locking the rear casters  302  and/or the front wheels  202 , etc.). In some embodiments, the brake pad  424  and/or the front chassis legs  480  include a resilient material (e.g., rubber, etc.) to at least one of (i) increase the friction between the brake pad  424  and/or the front chassis legs  480  and the ground surface  600  and (ii) attenuate loads transferred from the surgical cart  10  to the ground surface  600  (e.g., increasing the stability of the surgical cart  10 , increasing the accuracy of the surgical device  30 , etc.). According to an exemplary embodiment, the floor lock  400  does not lift the rear casters  302  of the surgical cart  10  off of the ground surface  600 . This may advantageously reduce the amount of force required to engage the floor lock  400  with the ground surface  600  to immobilize the surgical cart  10  (e.g., as compared to lifting the rear end  14  of the surgical cart  10  off of the ground surface  600  with the floor lock  400 , etc.). The floor lock  400  applies force to the ground surface via the brake pad  424  thereby preventing movement of the rear end  14  of the surgical cart  10 . According to an exemplary embodiment, the front wheels  202  retract and/or the front chassis legs  480  extend such that the front wheels  202  no longer touch the ground surface  600  when the front chassis legs  480  engage the ground surface  600  (e.g., free to rotate, completely unloaded, etc.). 
     Referring now to  FIG.  5 G , the floor lock  400 , the carriage mount  320 , and/or the carriage mount  370 , along with the front chassis legs  480 , provide a three-point support structure  500  for the surgical cart  10  when the floor lock  400  is in the machining configuration  406 . Optimum stability of the surgical cart  10  during use of the surgical device  30  (e.g., when the surgical device  30  is moving, used in a procedure, machining, etc.) is achieved when the mass of the surgical cart  10  is kinematically supported by three points and the center of the mass is located at the approximate centroid of an area defined by the three points. According to an exemplary embodiment, the surgical cart  10  is supported by the three-point support structure  500  which includes each of the front chassis legs  480 , the carriage mount  320 , the carriage mount  370 , and/or the brake pad  424  of the brake  420 . Also, a center of mass  510  of the surgical cart  10  is substantially near the centroid of the area defined by the three-point support structure  500 . Therefore, the surgical cart  10  has three point stability when the floor lock  400  is in the machining configuration  406  (i.e., increased stability when stationary for machining) and quasi-four point stability (e.g., from the front wheels  202  and the pivoting carriage assembly  300 , etc.) when the floor lock  400  is in the transportation configuration  402  (i.e., increased stability when moving, prevents rocking, fluttering, and tipping during transport). According to an exemplary embodiment, the chassis  100  is relatively stiff to minimize deflection as loads are transferred through the surgical cart  10  from the surgical device  30  during operation (e.g., machining, etc.), further increasing the accuracy of the surgical device  30 . 
     In an alternative embodiment, the extension lever  460 , the lift linkages  470 , the coilover  482 , and/or the front chassis legs  480  are omitted. In the alternative embodiment, the carriage mount  320 , the carriage mount  370 , and/or the floor lock  400 , along with the front wheels  202 , provide a three-point support structure  502  for the surgical cart  10  when the floor lock  400  is in the machining configuration  406  (e.g., without raising or lowering any portion of the surgical cart  10 , the front portion  110  of the chassis  100  may not kneel, etc.). Engaging the floor lock  400  may (i) lock the front wheels  202  in the current position thereof or (ii) pivot and/or lock the front wheels  202  into a desired positon (e.g., a fore-and-aft positon, a lateral position, etc.). In one embodiment, actuating the floor lock  400  orients and/or locks the front wheels  202  in a longitudinal direction (i.e., forward). Longitudinally disposing the front wheels  202  (as shown in  FIGS.  5 A- 5 B ) may prevent lateral movement of the front end  12 , thereby establishing complete immobility of the surgical cart  10 . In another embodiment, actuating the floor lock  400  orients and/or locks the front wheels  202  in a lateral direction (i.e., sideways). Laterally disposing the front wheels  202  may further prevent longitudinal movement of the front end  12  of the surgical cart  10 . In other embodiments, engaging the floor lock  400  neither locks the front wheels  202  nor orients the front wheels  202  into a desired position (e.g., the front wheels  202  may be manually pivoted into a desired positon, the front wheels  202  may be manually locked, etc.). In some embodiments, the front wheels  202  include a brake mechanism positioned to rotationally fix the front wheels  202 . In yet another alternative embodiment, the surgical cart  10  includes one or more floor locks  400  positioned at the front end  12  of the surgical cart  10  to immobilize the front end  12  of the surgical cart  10 . In a further alternative embodiment, the chassis  100  includes one or more rear chassis legs such that the surgical cart  10  is able to be lowered onto the rear chassis legs (e.g., such that the front chassis legs  480  and the rear chassis leg(s) immobilize the surgical cart  10 , the front wheels  202  and the rear chassis leg(s) immobilize the surgical cart  10 , etc.). 
     Referring now to  FIGS.  5 A- 5 B,  6 - 9 B,  11 , and  13 - 17 B , the wheel steering assembly  200  is configured to facilitate maneuvering the surgical cart  10  in a plurality of steering modes (e.g., fore-and-aft, turn-on-axis, lateral, etc.). As shown in  FIGS.  5 A- 5 B,  6 ,  7 A,  8 A,  9 A,  11 ,  13 - 14 B,  15 B,  16 B, and  17 B , the wheel steering assembly  200  includes a steering frame member, shown as steering swing arm  210 . As shown in  FIGS.  6 - 7 A,  8 A,  9 A,  11 ,  13 - 14 B,  15 B,  16 B, and  17 B , the steering swing arm  210  includes a plate, shown as steering plate  212 ; a wall, shown as wall  214 , that extends around a periphery of the steering plate  212 ; and a pair of brackets, shown as wheel brackets  216 , coupled to the wall  214 . The wheel brackets  216  are configured to couple the front wheels  202  to the steering swing arm  210 . As shown in  FIG.  7 B , the front portion  110  of the chassis  100  defines apertures, shown as wheel apertures  116 , positioned such that the wheel brackets  216  extended from the wheel apertures  116 . Thus, the front wheels  202  are able to be positioned outside of the chassis  100 . 
     As shown in  FIGS.  6 - 7 A,  8 A, and  9 A , the steering swing arm  210  includes a pair of mounts, shown as steering assembly mounts  218 . As shown in  FIGS.  5 A- 5 B , the steering assembly mounts  218  are configured to couple the wheel steering assembly  200  to the chassis  100  within the inner volume  112 . According to an exemplary embodiment, the middle portion  130  of the chassis  100  defines a set of apertures that correspond with apertures defined by the steering assembly mounts  218 . The corresponding apertures receive fasteners (e.g., nuts and bolts, etc.) which removably couples the steering swing arm  210  to the chassis  100 . According to an exemplary embodiment, the steering assembly mounts  218  pivotably couple the steering swing arm  210  to the chassis  100  which thereby facilitates the rotation of the steering swing arm  210  as the front portion  110  of the chassis  100  kneels (e.g., when the floor lock  400  is engaged, etc.). 
     As shown in  FIGS.  11 ,  13 - 14 B,  15 B,  16 B, and  17 B , the steering swing arm  210  includes a pair of pivots, shown as steering assembly pivots  219 , extending laterally therefrom. As shown in  FIG.  11   , the middle portion  130  of the chassis  100  defines a pair of mounts, shown as couplers  132 , that are positioned to receive the steering assembly pivots  219 . The steering assembly pivots  219  are thereby configured to couple the wheel steering assembly  200  to the chassis  100  within the inner volume  112 . According to an exemplary embodiment, the steering assembly pivots  219  pivotably couple the steering swing arm  210  to the chassis  100  which thereby facilitates the rotation of the steering swing arm  210  as the front portion  110  of the chassis  100  kneels (e.g., when the floor lock  400  is engaged, etc.). 
     As shown in  FIGS.  6 - 7 A,  8 A,  9 A,  11 , and  13   , the wheel steering assembly  200  includes a steering mechanism, shown as steering mechanism  240 . According to an exemplary embodiment, the steering mechanism  240  is configured as a manually actuated mechanical linkage and/or crank system that steers the front wheels  202  in response to a manual actuation from an operator of the surgical cart  10 . According to an exemplary embodiment, the mechanical linkage and/or crank system of the steering mechanism  240  eliminates the need for belts, gears, sprockets, and/or adjustments, thereby reducing costs and minimizing maintenance. In an alternative embodiment, the steering mechanism  240  is an electromechanical linkage system that is actuated by an actuator (e.g., an electric motor, etc.) in response to receiving an command from the computing system  40  (e.g., a command based on an operator input received by the display device  42  or input device  44 , etc.). In another alternative embodiment, each of the front wheels  202  and/or rear casters  302  include an actuator (e.g., an electric motor, etc.) positioned to steer each of the front wheels  202  and the rear casters  302  independently in response to receiving a command from the computing system  40 . In some embodiments, an electric motor is adapted to propel the surgical cart  10  by providing rotational energy to at least one of the front wheels  202  and the rear casters  302 . 
     As shown in  FIGS.  5 A- 5 B,  6 - 7 A,  8 A, and  9 A , the steering mechanism  240  includes a handle  242 . The handle  242  is configured to provide an operator of the surgical cart  10  with a lever to apply leverage in order to reconfigure the steering mechanism  240  into the plurality of steering modes. As shown in  FIGS.  5 A- 5 B and  6   , the handle  242  is coupled to a shaft  244  which defines an axis, shown as rotational axis  241 . By way of example, turning handle  242  about rotational axis  241  as indicated by directional arrow  243  may reconfigure the steering mechanism  240  into a desired steering mode. 
     As shown in  FIGS.  5 A- 5 B,  6 , and  13   , the shaft  244  extends from the handle  242  to an indexing member, shown as indexing case  246 . In other embodiments, the shaft  244  extends from one of the handgrips  52  to the indexing case  246 . As shown in  FIGS.  5 A- 5 B , the indexing case  246  is coupled to the chassis  100  (e.g., via a fastener, etc.). As shown in  FIGS.  6 - 7 A,  8 A,  9 A, and  13   , the indexing case  246  include a first linkage member, shown as rotational linkage  248 , rotationally coupled to the shaft  244  and disposed within the indexing case  246 . The rotational linkage  248  includes an extension, shown as retaining leg  247 . The retaining leg  247  is configured to abut the indexing case  246  to limit the rotation of the rotational linkage  248  in a first direction (e.g., clockwise, etc.) while allowing rotation of the rotational linkage  248  in an opposing second direction (e.g., counterclockwise, etc.). The rotational linkage  248  also defines a plurality of indentations, shown as indicator indentations  249 . Each indicator indentation  249  may correspond with an orientation of the handle  242  that is associated with a steering mode of the surgical cart  10 . For example, a first indicator indentation  249  may be associated with a fore-and-aft steering mode, a second indicator indentation  249  may be associated with a turn-on-axis steering mode, and a third indicator indentation  249  may be associated with a lateral steering mode. According to an exemplary embodiment, as the rotational linkage  248  rotates, the indicator indentations  249  interact with a movable member (e.g., an indexer, a spring-loaded ball bearing, etc.) positioned within the indexing case  246  to provide an operator with feedback (e.g., tactile feedback, etc.) that a preset steering mode is engaged. The indicator indentations  249  may also facilitate holding the steering mechanism  240  in a desired one of the preset steering modes (e.g., via the interaction between the indicator indentation  249  and the moveable member, etc.). 
     As shown in  FIGS.  6 - 7 A,  8 A,  9 A, and  13   , the rotational linkage  248  is coupled to a first end of a second linkage member, shown as connecting linkage  250 . As shown in  FIGS.  6 - 7 A,  8 A, and  9 A , an opposing second end of the connecting linkage  250  is coupled to a transfer member, shown as transfer block  252 . The connecting linkage  250  is configured to transfer the rotational input provided by the rotational linkage  248  from the handle  242  to the transfer block  252 . As shown in  FIGS.  7 A,  8 A, and  9 A , the transfer block  252  is coupled to a first end of a pair of third linkages, shown as intermediate linkages  256 . Thus, the transfer block  252  couples the connecting linkage  250  to the intermediate linkages  256 . As shown in  FIGS.  6 - 7 A,  8 A, and  9 A , the transfer block  252  is slidably coupled to a slide member, shown as linear slide  254 . Thus, the transfer block  252  converts the rotational input from the handle  242  to a linear translation along the linear slide  254 . 
     As shown in  FIGS.  7 A,  8 A, and  9 A , an opposing second end of each of the intermediate linkages  256  is coupled to a first end of a fourth linkage, shown as rotational linkage  258 , and a first end of a fifth linkage, shown as driving linkage  260 . As shown in  FIGS.  6 - 7 A,  8 A, and  9 A , an opposing second end of the rotational linkages  258  is rotationally coupled to the steering plate  212 . Thus, rotational linkages  258  rotate about a point of connection between the opposing second end of the rotational linkages  258  and the steering plate  212 . As shown in  FIGS.  7 A,  8 A , and  9 A, as the transfer block  252  is repositioned along the linear slide  254  (e.g., by actuating the handle  242 , etc.), the intermediate linkages  256  both rotate and translate, while the rotational linkages  258  only rotate. Therefore, the movement of the intermediate linkages  256  is defined by the linear movement of the transfer block  252  and the rotational movement of the rotational linkages  258 . 
     As shown in  FIGS.  7 A,  8 A, and  9 A , an opposing second end of the driving linkages  260  is coupled to a first end of a sixth linkage, shown as wheel linkage  262 . An opposing second end of the wheel linkages  262  is coupled to the front wheels  202 . As the handle  242  is actuated, the driving linkages  260  both rotate and translate causing the opposing second end of the driving linkages  260  to extend through the wheel apertures  116 . The extension outwards from the wheel apertures  116  cause the wheel linkages  262  to rotate about a vertical axis, shown as wheel axis  220  (shown in  FIG.  6   ). Accordingly, the rotation of the wheel linkages  262  causes the front wheels  202  to rotate about the wheel axis  220 . 
     As shown in  FIGS.  13 - 14 B,  15 B,  16 B, and  17 B , the opposing second end of the connecting linkage  250  is coupled to a crank mechanism, shown as crank mechanism  700 . As shown in  FIGS.  14 A- 14 B,  15 B,  16 B, and  17 B , the crank mechanism  700  includes a rotational synchronization element, shown as cam  710 , a rotational element, shown as rotor  720 , a pair of linkages, shown as arms  730 , and a pair of pivoting joints, shown as wheel joints  740 . According to an exemplary embodiment, the rotor  720  is rotationally coupled to the steering plate  212  (e.g., with a rotational bearing, etc.) of the steering swing arm  210 . The cam  710  is rotationally fixed to the rotor  720  such that the cam  710  rotates therewith, according to an exemplary embodiment. 
     As shown in  FIGS.  14 B,  15 B,  16 B, and  17 B , the cam  710  defines a first interface, shown as connecting linkage interface  712 , a second interface, shown as first arm connection interface  714 , and a third interface, shown as second arm connection interface  716 . The opposing second end of the connecting linkage  250  couples to the connecting linkage interface  712 , a first end of a first arm  730  couples to the first arm connection interface  714 , and a first end of a second arm  730  couples to the second arm connection interface  716 . As shown in  FIGS.  14 A- 14 B , the cam  710  is spaced from the rotor  720  such that the first end of the first arm  730  and the first end of the second arm  730  is positioned therebetween. As shown in  FIGS.  14 B,  15 B,  16 B, and  17 B , an opposing second end of the first arm  730  is coupled to a first wheel joint  740  and an opposing second end of the second arm  730  is coupled to a second wheel joint  740 . As shown in  FIGS.  15 B,  16 B, and  17 B , the wheel joints  740  are pivotably coupled to the wheel brackets  216 . Accordingly, the rotation of the wheel joints  740  causes wheel axles  203  and thereby the front wheels  202  to rotate about the wheel axis  220  (see  FIG.  13   ). 
     As shown in  FIGS.  15 B,  16 B, and  17 B , movement of the connecting linkage  250  (e.g., caused by the rotation of the handle  242 , the handgrip  52 , etc.) causes the cam  710  and the rotor  720  to rotate (e.g., about a central axis thereof, etc.). Such rotation may drive the arms  730  to extend laterally outward (e.g., through the wheel apertures  116 , etc.), thereby driving the wheel joints  740  to rotate within the wheel brackets  216  to facilitate pivoting the front wheels  202  in various positions. According to an exemplary embodiment, the crank mechanism  700  (e.g., the rotor  720 , the cam  710 , etc.) is laterally offset relative to a longitudinal centerline of the surgical cart  10  (e.g., laterally biased towards one side, etc.). According to an exemplary embodiment, the first wheel joint  740  and the second wheel joint  740  have different characteristics (e.g., shapes, dimensions, configurations, etc.). According to an exemplary embodiment, the cam  710  has an asymmetric shape. The lateral offset of the crank mechanism  700 , the asymmetry of the cam  710 , and/or the different characteristics of the wheel joints  740  maintain the front wheels  202  in sync (e.g., the front wheels  202  do not pivot at different rates, angular rotation of the front wheels  202  is synchronized, etc.). 
     According to an exemplary embodiment, actuation of the handle  242  and/or the handgrip  52  corresponds with a 1:1 ratio of handle  242  and/or handgrip  52  rotation to front wheel  202  rotation (i.e., an amount of rotation of the handle  242  and/or the handgrip  52  directly corresponds with an amount of rotation of the front wheels  202 ). For example, a 45 degree turn of the handle  242  and/or the handgrip  52  corresponds with a 45 degree turn of the front wheels  202 . In other embodiments, the amount of rotation of the handle  242  and/or the handgrip  52  does not directly correspond with the amount of rotation of the front wheels  202  (e.g., a 1:2 ratio, a 2:1 ratio, a 1:3 ratio; a 3:1 ratio; etc.). According to an exemplary embodiment, the steering mechanism  240  isolates external loads on the front wheels  202  from the handle  242  and/or the handgrip  52 . In an alternative embodiment, the steering mechanism  240  steers the rear casters  302  and the front wheels  202  are free to rotate. In another alternative embodiment, the steering mechanism  240  steers at least one of the front wheels  202  and the rear casters  302 . In yet another alternative embodiment, at least one of the front wheels  202  and the rear casters  302  are able to be both steered and free to rotate (i.e., the steering mechanism  240  is able to be selectively disengaged from the front wheels  202  and/or rear casters  302 ). 
     According to the exemplary embodiment shown in  FIGS.  7 A- 7 B and  15 A- 15 B , the surgical cart  10  is configured in a first steering mode, shown as fore-and-aft steering mode  270 . As shown in  FIGS.  7 A- 7 B , the handle  242  of the steering mechanism  240  is oriented in a first position, shown as fore-and-aft position  272 , corresponding to the fore-and-aft steering mode  270 . As shown in  FIG.  15 A , the handgrip  52  is orientated in a first position, shown as fore-and-aft position  72 . While the handle  242  is oriented in the fore-and-aft position  272  and/or the handgrip  52  is oriented in the fore-and-aft position  72 , the front wheels  202  align such that they are parallel with the longitudinal axis of the surgical cart  10  (e.g., forward facing alignment, etc.). Thus, the surgical cart  10  is able to be maneuvered by an operator in a conventional way such as in a forward direction or a reverse direction, as indicated by directional arrow  274 . Also, the surgical cart  10  is able to turn while moving forward or backward while in the fore-and-aft steering mode  270  since the rear casters  302  are free to rotate (e.g., about the vertical axis  340 , etc.). 
     According to the exemplary embodiment shown in  FIGS.  8 A- 8 B and  16 A- 16 B , the surgical cart  10  is configured in a second steering mode, shown as turn-on-axis steering mode  280 . As shown in  FIGS.  8 A- 8 B , the handle  242  of the steering mechanism  240  is oriented in a second position, shown as turn-on-axis position  282 , corresponding to the turn-on-axis steering mode  280  (e.g., the handle  242  is turned approximately 45 degrees from the fore-and-aft position  272 , etc.). As shown in  FIG.  16 A , the handgrip  52  is oriented in a second position, shown as turn-on-axis position  82 , corresponding to the turn-on-axis steering mode  280  (e.g., the handgrip  52  is turned approximately 45 degrees from the fore-and-aft position  72 , etc.). While the handle  242  is oriented in the turn-on-axis position  282  and/or the handgrip  52  is oriented in the turn-on-axis position  82 , the front wheels  202  turn in towards the surgical cart  10  into a recess, shown as recess  114 , defined by the front portion  110  of the chassis  100  (e.g., at an angle of approximately 45 degrees relative to the longitudinal axis of the surgical cart  10 , etc.). Thus, the surgical cart  10  is able to be maneuvered by an operator in a rotational direction, as indicated by directional arrow  284 , about a central axis  286  of the surgical cart  10 . As shown in  FIGS.  8 A- 8 B and  16 A , the rear caster  302  rotate accordingly when the surgical cart  10  is maneuvered while in the turn-on-axis steering mode  280  to facilitate a zero radius turn (i.e., the surgical cart  10  is rotatable in place about the central axis  286 ). 
     According to the exemplary embodiment shown in  FIGS.  9 A- 9 B and  17 A- 17 B , the surgical cart  10  is configured in a third steering mode, shown as lateral steering mode  290 . As shown in  FIGS.  9 A- 9 B , the handle  242  of the steering mechanism  240  is oriented in a third position, shown as lateral position  292 , corresponding to the lateral steering mode  290  (e.g., the handle  242  is turned approximately 90 degrees from the fore-and-aft position  272 , etc.). As shown in  FIG.  17 A , the handgrip  52  is oriented in a third position, shown as lateral position  92 , corresponding to the lateral steering mode  290  (e.g., the handgrip  52  is turned approximately 90 degrees from the fore-and-aft position  72 , etc.). While the handle  242  is oriented in the lateral position  292  and/or the handgrip  52  is oriented in the lateral position  92 , the front wheels  202  turn completely into the recesses  114  such the front wheels  202  are perpendicular to the longitudinal axis of the surgical cart  10  (e.g., at a 90 degree angle to the longitudinal axis of the surgical cart  10 , etc.). Thus, the surgical cart  10  is able to be maneuvered by an operator in a lateral direction, as indicated by directional arrow  294 . As shown in  FIGS.  9 A- 9 B and  17 A , the rear caster  302  rotate accordingly when the surgical cart  10  is maneuvered while in the lateral steering mode  290  to facilitate moving the surgical cart  10  laterally. Laterally maneuvering the surgical cart  10  may be useful following moving the surgical cart  10  (e.g., while in the fore-and-aft steering mode  270 , etc.) into a surgical operating room to position the surgical cart  10  next to an operating table. Traditional surgical carts with fixed front wheels make this difficult. The cart has to be backed up, pivoted and moved back in. Sometimes this has to be repeated several times until the position is correct. This often requires handling the cart from the front end which may be in a sterile field of the operating room, which is not ideal. The surgical cart  10  of the present disclosure facilitates lateral translation at the operating table from the rear end  14  of the surgical cart  10  in a non-sterile field of an operating room. Further, the pivoting carriage assembly  300  facilitates evenly loading the front wheels  202  for controlled lateral translation. 
     Referring back to  FIGS.  7 B,  8 B, and  9 B , in an alternative embodiment, the handle  242  of the steering mechanism  240  is omitted and one of the handgrips  52  is mechanically coupled to the steering mechanism  240  to reconfigure the surgical cart  10  between the various steering modes (as described above in regards to  FIGS.  15 A,  16 A, and  17 A ). In another alternative embodiment, each of the handgrips  52  independently controls the rotation of the front wheels  202  (e.g., the right handgrip  52  controls the pivoting of the right front wheel  202 , the left handgrip  52  controls the pivoting of the left front wheel  202 , one rotates clockwise and the other rotates counter-clockwise, etc.). 
     As shown in  FIGS.  10 ,  15 A,  16 A, and  17 A , the handgrip  52  (e.g., that controls the rotation of the front wheels  202 , etc.) includes a push button, shown as lock button  56 . In some embodiments, the lock button  56  is configured to facilitate locking the rotational position of the front wheels  202  (e.g., to prevent inadvertent rotation of the handgrip  52  and the front wheels  202 , etc.). In some embodiments, the lock button  56  is configured to facilitate unlocking the rotational position of the front wheel  202  (e.g., a wheel lock for the front wheels  202  is biased into a locked position, etc.). In some embodiments, the position of the front wheels  202  automatically locks in one or more positions (e.g., when the handgrip  52  is oriented into the fore-and-aft position  72 , etc.). As shown in  FIG.  15 A , the handgrips  52  are angled relative to a longitudinal axis of the surgical cart  10  (e.g., angled fifteen degrees relative to a longitudinal axis of the surgical cart  10 , providing a better ergonomic feel when pushing the surgical cart  10 , etc.). 
     The steering mechanism  240  herein is described in detail as being configured to facilitate selectively steering the front wheels  202  between the fore-and-aft position  272 , the turn-on-axis positon  282 , and the lateral position  292 . However, it should be understood that the front wheels  202  may be selectively pivoted between and/or locked at any position between the fore-and-aft position  272  and the lateral position  292  (e.g., the front wheels  202  may be positioned and/or locked at any angle between zero and ninety degrees relative to a longitudinal axis of the surgical cart  10 , etc.). 
     The term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, Z, X and Y, X and Z, Y and Z, or X, Y, and Z (i.e., any combination of X, Y, and Z). Thus, such conjunctive language is not generally intended to imply that certain embodiments require at least one of X, at least one of Y, and at least one of Z to each be present, unless otherwise indicated. 
     The construction and arrangement of the systems and methods as shown in the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.). For example, some elements shown as integrally formed may be constructed from multiple parts or elements, the position of elements may be reversed or otherwise varied and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present disclosure. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Also two or more steps may be performed concurrently or with partial concurrence. Such variation will depend on various factors, including software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations could be accomplished with standard programming techniques with rule based logic and other logic to accomplish the various connection steps, processing steps, comparison steps and decision steps. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present disclosure.