Patent Description:
Medical device suspension systems or carry systems are used in health treatment settings such as hospital examination rooms, clinics, surgery rooms and emergency rooms. These systems may suspend or support any variety of medical devices or components including surgical lights, supply consoles, patient monitors, camera detector heads, medical instruments, ventilator systems, suction devices, among others. The supports typically include a central shaft or support column that is suspended from the ceiling or mounted to a wall, and one or more generally horizontal extension arms mounted for rotational movement about the shaft. A frictional brake is provided near the pivot location of the extension arm that is operable to maintain the extension arm in the desired angular position and to permit angular adjustment by a suitable force against the extension arm. The extension arm can be rotatably adjusted about the column to a desired angular position to provide appropriate access to medical devices and components associated with the arm.

Most of the current support systems utilize mechanical radial braking devices to provide the required rotational performances of system components. The basic principle of these devices is that the force needed to achieve the desired level of frictional braking is applied in the radial direction, transverse or perpendicular to the axis of component rotation. One example is a clamp assembly that has a generally C-shape construction. The clamp assembly is installed over the central shaft and into a hub portion of the pivoting extension arm. An actuator, which may also be part of the hub, is used to urge opposite sides of the brake clamp toward and away from the shaft. This process creates a normal force between the brake clamp and the shaft, and provides necessary frictional force to control the pivotable movement of the arm around the shaft.

For some medical device suspension systems or carry systems, there remain various shortcomings, drawbacks, and disadvantages relative to certain applications. For example, the C-shape clamp assembly has a split ring structure that can only be installed by positioning the split ring at an upper end (or lower end) of the support shaft and sliding the ring to the appropriate axial position along the shaft, i.e. near the pivoting location of the extension arm. This typically is done in a factory prior to shipping and installing the system in a surgery room or clinic, since the brake assembly must already be located on the shaft prior to mounting the shaft to a support surface or prior to attaching the extension arm to the shaft. Servicing the brake assembly also can be problematic, since the support system must be disassembled to provide access to an upper or lower shaft end. This usually requires removal and transport of the system from its health treatment room to an appropriate service facility. The brake assembly of these medical device support systems therefore is not easily field replaceable/serviceable.

Prior art medical device support systems are shown in <CIT> and <CIT>.

Accordingly, there remains a need for further contributions in this area of technology.

The invention is as defined in claims <NUM>, <NUM>, and <NUM>, with further embodiments disclosed in the dependent claims.

The application relates to a multi-piece brake assembly for a medical device support system, in which the brake assembly has first and second discrete arc shape clamp pieces that can be easily assembled to, and removed from, a central shaft of the support system, and therefore simplifies and adds efficiency to the factory assembly and field service of the medical device support system.

According to one aspect of the invention, a medical device support system includes a central shaft; an extension arm having a support for a medical device and a hub at its proximal end mounted to the central shaft for pivotable movement about the central shaft; and, a brake assembly secured in the hub for rotation therewith and including first and second discrete arc shape clamp pieces that are detachably coupled to one another at one end for flexural movement relative to a coupling joint and that are free at an opposite end. The brake assembly includes an actuator configured to flex the first and second clamp pieces relative to the coupling joint toward and away from each other to respectively increase and decrease a frictional braking force to the central shaft.

Embodiments of the invention may include one or more of the following additional features separately or in combination.

The first and second arc shape clamp pieces may form a multi-piece split collar around the central shaft that is configured to contract and expand relative to the central shaft in response to flexural movement of the first and second arc shape clamp pieces relative to the coupling joint.

When the first and second clamp pieces are flexed toward each other to increase the frictional braking force to the central shaft, the first and second clamp pieces may have an arc shape contact with the outer periphery of the central shaft.

The brake assembly may be configured to operate in a passive manner, preventing motion of the extension arm relative to the central shaft by means of the frictional braking force, wherein the frictional braking force can be overcome by a user pushing on the extension arm.

The first and second arc shape clamp pieces may be diametrically opposed from one another on opposite sides of the central shaft.

The medical device may be a surgical light.

The first and second arc shape clamp pieces may include respective liners made of a material selected from polyolefins, polyesters, acetals, polyamides, fluorinated polymers, vinyls, acrylics, polycarbonates, polyimides, polysulphones, and blends and alloys thereof.

The first and second arc shape clamp pieces may include unreinforced, semi-crystalline thermoplastic polyester based on polyethylene terephthalate (PET-P).

The first and second arc shape clamp pieces include respective first and second polymer liners made of UHMW-PE.

Accoding to another aspect of the invention, a brake assembly for a medical device support system having a central shaft, includes first and second discrete arc shape clamp pieces that are detachably coupled to one another at one end for flexural movement relative to a coupling joint and that are free at an opposite end. The first and second arc shape clamp pieces are configured to flex relative to the coupling joint toward and away from each other to respectively increase and decrease a frictional braking force to the central shaft.

The first and second arc shape clamp pieces may be detachably coupled to one another by being interlocked to each other at the one end.

The one ends of the first and second arc shape clamp pieces may include respective first and second axially extending protrusions that circumferentially abut one another to resist flexural movement of the first and second arc shape clamp pieces toward each other relative to the coupling joint.

The one ends of the first and second arc shape clamp pieces may have respective first and second axially extending tabs and first and second axially extending notches, and the first axially extending tab may fit within the second axially extending notch and the second axially extending tab may fit within the first axially extending notch.

The one ends of the first and second arc shape clamp pieces may be slidable axially and radially relative to one another.

The first and second arc shape clamp pieces may be detachably coupled to one another by a hinge at the one end.

The first and second arc shape clamp pieces may have an identical geometry.

According to another aspect of the invention, there is provided a method of installing a brake assembly in a medical device support system having a central shaft, the method including providing first and second discrete arc shape clamp pieces of the brake assembly at one side of a central shaft; moving either the connecting ends or the free ends around the central shaft to an opposite side of the central shaft so that the connecting ends and free ends are situated at opposite sides of the central shaft; coupling the connecting ends of the first and second arc shape clamp pieces together for flexural movement relative to a coupling joint at the connecting ends and for free movement at the free ends; arranging the first and second arc shape clamp pieces relative to the central shaft to respectively increase and decrease a frictional braking force to the central shaft in response to flexural movement of the first and second arc shape clamp pieces relative to the coupling joint; and, securing the brake assembly in a hub of an extension arm for rotation with the extension arm about the central shaft.

The arranging may include arranging the first and second arc shape clamp pieces to form a multi-piece split collar around the central shaft that is configured to contract and expand relative to the central shaft in response to flexural movement of the first and second arc shape clamp pieces relative to the coupling joint.

The coupling may include interlocking the connecting ends of the first and second arc shape clamp pieces.

The coupling may include sliding axially the first and second arc shape clamp pieces relative to one another.

The coupling may include hingedly connecting the connecting ends of the first and second arc shape clamp pieces.

The following description and the annexed drawings set forth certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features according to aspects of the invention will become apparent from the following detailed description when considered in conjunction with the drawings.

While the present invention can take many different forms, for the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, the scope of the invention is defined by the appended claims. Any alterations and further modifications of the described embodiments, and any further applications of the principles of the invention as described herein, are contemplated as would normally occur to one skilled in the art to which the invention relates, as long as they remain within the scope of the claims.

<FIG> show a medical device support system <NUM> that includes a central shaft <NUM>, at least one extension arm <NUM> rotatably mounted to the shaft <NUM>, and a brake assembly <NUM> secured in a hub <NUM> of the extension arm <NUM> for rotation with the extension arm <NUM>. As shown in <FIG> and <FIG>, the brake assembly <NUM> includes first and second discrete arc shape clamp pieces <NUM>, <NUM> that are detachably coupled to one another at one end <NUM>, <NUM> for flexural movement relative to a coupling joint <NUM> while being free to move at an opposite end <NUM>, <NUM>. An actuator <NUM> is configured to flex the first and second clamp pieces <NUM>, <NUM> relative to the coupling joint <NUM> toward and away from each other to respectively increase and decrease a frictional braking force to the central shaft <NUM>. As will be described in greater detail below, the multi-piece structure of the brake assembly <NUM> enables the first and second arc shape clamp pieces <NUM>, <NUM> to be easily assembled to, and removed from, the central shaft <NUM>, and therefore simplifies and adds efficiency to the factory assembly and field service of the medical device support system <NUM>.

Referring to <FIG>, the illustrative medical device support system <NUM> is a suspension type carrying support system for use in a hospital examination room, a clinic, a surgery room, an emergency room, among others. The central shaft <NUM> extends along an axis A-A. The central shaft <NUM> may be fixed to a ceiling support <NUM> to remain stationary relative to the ceiling. It will be appreciated, of course, that the medical device support system <NUM> may have any suitable suspension or carrying structure and that the central shaft <NUM> may be attached to a ceiling, wall, floor, movable cart, or a combination of the foregoing. The central shaft <NUM> of the medical device support system <NUM> has a circular shape in axial cross section and extends vertically downward from the ceiling support <NUM>. A column section <NUM> surrounds an upper portion of the central shaft <NUM> and houses upper portions of accessory and service lines such as power cables for surgical lights and other power requirements, control wiring for control electronics, and/or tubing for irrigation, suction, etc. A plurality of extension arms <NUM>, three in the illustrative embodiment, are mounted for rotatable movement to the central shaft <NUM> and extend laterally outward from the central shaft <NUM>. In the <FIG> embodiment, the extension arms <NUM> extend horizontally, or perpendicularly, relative to the central shaft <NUM>.

Each extension arm <NUM> is equipped with a support <NUM> for a medical device <NUM>. The illustrative support <NUM> is a vertical column <NUM> extending downward from a distal end <NUM> of the horizontal extension arm <NUM>. The vertical column <NUM> may be mounted for rotatable movement to the distal end <NUM> of the extension arm <NUM> by means of a bearing, and may be equipped to frictionally engage the distal end <NUM>, for example, by means of a brake assembly <NUM> in the same manner that the extension arm <NUM> is rotatably mounted and braked relative to the central shaft <NUM>. In the <FIG> embodiment, the medical device <NUM> comprises a surgical light <NUM> attached to a bottom end of the vertical column <NUM>. Of course, the medical device support system <NUM> need not be limited as such and other embodiments are contemplated. For example, the medical device <NUM> may comprise a patient monitor, a supply console, a camera detector head, a medical instrument, a ventilator system, a suction device, among others. A control console, if provided, may provide controls for navigation of a medical instrument that is either coupled to or remote from the extension arm <NUM>.

The hub <NUM> is located at the proximal end <NUM> of the extension arm <NUM> and is mounted to the central shaft <NUM> for pivotable movement about the central shaft <NUM>. In the illustrative embodiment, each hub <NUM> includes upper and lower bearing mounts <NUM>, <NUM>, shown in <FIG>, that house respective upper and lower pivot bearings mounted to the central shaft <NUM>. Any suitable pivot bearings may be used to facilitate the relative rotational movement between the extension arm <NUM> and the central shaft <NUM>, including for example ball bearings, sleeve bearings, bushings, rotary joints and/or swivel joints. Each hub <NUM> provides passages for routing accessory and service lines from the upper column section <NUM> to the radial extent <NUM> of the extension arm <NUM> and/or vice versa. Each hub <NUM> is also provided with an access opening <NUM> to enable access to the central shaft <NUM>, the brake assembly <NUM>, and the accessory and service lines.

Reference is now made to <FIG> which show greater detail of the brake assembly <NUM>. The brake assembly <NUM> is secured in the hub <NUM> for rotation with the hub <NUM>. As shown in <FIG> and <FIG>, the brake assembly <NUM> includes first and second discrete arc shape clamp pieces <NUM>, <NUM> that are detachably coupled to one another at one end <NUM>, <NUM> for flexural movement relative to a coupling joint <NUM> while being free to move at an opposite end <NUM>, <NUM>. In the illustrative embodiment, each of the first and second discrete arc shape clamp pieces <NUM>, <NUM> of the brake assembly <NUM> has a circumferential portion <NUM>, <NUM>, a connecting end <NUM>, <NUM> at one end of the circumferential portion <NUM>, <NUM>, and a free end <NUM>, <NUM> at an opposite end of the circumferential portion <NUM>, <NUM>. As shown in <FIG>, the arc shape clamp pieces <NUM>, <NUM> in their assembled state form a multi-piece split collar or ring wherein the circumferential portions <NUM>, <NUM> form the ring portion thereof, an interface between the connecting ends <NUM>, <NUM> forms a first split thereof, and a gap between the free ends <NUM>, <NUM> forms a second split thereof. The circumferential portions <NUM>, <NUM> are sized to fit within and radially inward of inner circumferential portions <NUM>, <NUM> of the hub <NUM>. As shown in <FIG>, the arc shape clamp pieces <NUM>, <NUM> may rest by means of gravity directly on the lower bearing mount <NUM>. A retaining snap ring may be mounted in a groove in the central shaft <NUM> immediately above, or a slight clearance above, the arc shape clamp pieces <NUM>, <NUM> and/or immediately below, or a slight clearance below, the arc shape clamp pieces <NUM>, <NUM> to axially retain or guide the arc shape clamp pieces <NUM>, <NUM> relative to the central shaft <NUM>.

The free ends <NUM>, <NUM> of the arc shape clamp pieces <NUM>, <NUM> include tabs <NUM>, <NUM> that protrude radially outwardly relative to the circumferential portions <NUM>, <NUM>. As shown in <FIG> and <FIG>, the radially protruding tabs <NUM>, <NUM> fit within a radially protruding notch <NUM> in the hub <NUM>, which notch <NUM> is disposed circumferentially between the inner circumferential portions <NUM>, <NUM> of the hub <NUM>. The tabs <NUM>, <NUM>, when installed in the hub notch <NUM>, circumferentally oppose one another and form a circumferential gap therebetween referred to herein as a deflection compensation split <NUM>.

The brake assembly <NUM> further includes an actuator <NUM> that is housed in a wall portion <NUM> of the hub <NUM>, as shown in <FIG> and <FIG>. The actuator <NUM> is operative selectively to apply a compressive force to the tabs <NUM>, <NUM> to urge the first and second arc shape clamp pieces <NUM>, <NUM> toward one another thereby to impart a frictional braking force to the central shaft <NUM>. In the illustrative embodiment, the actuator <NUM> comprises a set screw <NUM> although any type of actuator <NUM> may be employed that is operative to urge the first and second arc shape clamp pieces <NUM>, <NUM> toward one another. The set screw <NUM> is configured to apply a load to the rear of the tab <NUM>. The set screw <NUM> is threaded into the wall portion <NUM> of the hub <NUM> and when threaded inward compresses the tab <NUM> toward the opposite tab <NUM>. The opposite tab <NUM> provides resistance to the compressive force applied by the set screw <NUM> by resting against a wall <NUM> of the notch <NUM> in the hub <NUM>.

In operation, tightening the set screw <NUM> compresses the tabs <NUM>, <NUM> and thereby narrows the deflection compensation split <NUM> and flexes the first and second arc shape clamp pieces <NUM>, <NUM> toward one another relative to the coupling joint <NUM>. Loosening the set screw <NUM> causes the tabs <NUM>, <NUM> to separate from one another owing to the resistive force imparted by the notch wall <NUM> of the hub <NUM> against the rear of the tab <NUM>, which results in the deflection compensation split <NUM> expanding and the first and second arc shape clamp pieces <NUM>, <NUM> unflexing away from one another relative to the coupling joint <NUM>. Thus, the deflection compensation split <NUM> between the free ends <NUM>, <NUM> compensates for deflection caused by the application of compressive force on the tabs <NUM>, <NUM>, which creates a tangential frictional force that supplies the braking relative to the central shaft <NUM>. The set screw <NUM>, or actuator <NUM>, is configured to increase and decrease the frictional braking force applied by the brake assembly <NUM> to the central shaft <NUM> to respectively increase and decrease the resistance to pivotable movement of the extension arm <NUM> about the central shaft <NUM>. The actuator <NUM> and brake assembly <NUM> are configured to operate in a passive manner, preventing motion of the extension arm <NUM> relative to the central shaft <NUM> by means of an "always-on" frictional braking force that can be overcome by a user pushing on the extension arm <NUM>. The amount of frictional resistance can be adjusted as desired by the user by adjusting the actuator <NUM>. The actuator <NUM> can be used to adjust the frictional resistance as suited for a particular physician and/or on a periodic basis to ensure the previously set frictional resistance still is in place and not loosened over time.

It will be appreciated that a suitable actuator can be employed to generate a lock mode, a frictional resistance mode, and/or a release mode. For example, the actuator can be configured to adjust the brake assembly <NUM> to generate a braking force, whether by friction or an interengaging mechanism such as a cam lock or piston lock, sufficient to lock the extension arm <NUM> to the central shaft <NUM>, and/or to generate a frictional braking force that prevents rotation of the extension arm <NUM> about the central shaft <NUM> yet enables a user to overcome the resistance by pushing the extension arm <NUM> about the central shaft <NUM>, and/or to generate a relatively lower or zero frictional braking force sufficient to free or release the extension arm <NUM> for pivotable movement about the central shaft <NUM> with relatively less or negligible force by the user. It will further be appreciated that the brake assembly <NUM> could be adapted for an active braking system, one which provides an active braking functionality that can apply a frictional braking force actively, for example, by means of electromagnetic actuation, pneumatic actuation, or hydraulic actuation.

The multi-piece split collar that is formed by the first and second arc shape clamp pieces <NUM>, <NUM> is disposed around the central shaft <NUM> and is configured to contract and expand relative to the central shaft <NUM> in response to the flexural movement of the first and second arc shape clamp pieces <NUM>, <NUM> relative to the coupling joint <NUM>. As will be appreciated, as the first and second arc shape clamp pieces <NUM>, <NUM> of the brake assembly <NUM> are flexed relative to the coupling joint <NUM>, the circumferential portions <NUM>, <NUM> and free ends <NUM>, <NUM> of the arc shape clamp pieces <NUM>, <NUM> move closer together and farther apart to respectively contract and expand the split collar. As shown in <FIG>, when the first and second clamp pieces <NUM>, <NUM> are flexed toward each other to increase the frictional braking force applied to the central shaft <NUM>, the first and second clamp pieces <NUM>, <NUM> each have an angular range or arc shape contact <NUM>, <NUM> with the outer periphery <NUM> of the central shaft <NUM> of about <NUM> degrees, or a total of about <NUM> degrees. Of course, the multi-piece split collar may be formed by more than two discrete arc shape clamp pieces, for example, three or four arc shape clamp pieces, with circumferentially adjacent pieces being detachably coupled together. Further, although the illustrative first and second arc shape clamp pieces <NUM>, <NUM> are diametrically opposed from one another on opposite sides of the central shaft <NUM>, it will be appreciated that the arc shape clamp pieces <NUM>, <NUM> may be other than diametrically opposed, for example, where there are more than two arc shape clamp pieces provided. For example, four arc shape clamp pieces may be equally circumferentially disposed about the central shaft <NUM>; that is, each piece may be <NUM> degrees apart from an adjacent piece.

It will also appreciated that the angular range contact of the arc shape clamp pieces may be other than <NUM> degrees, and thus other than a total of <NUM> degrees. For example, <FIG> shows an alternate embodiment of an arc shape clamp piece <NUM> for which the angular range contact with the central shaft <NUM> is about <NUM> degrees, thus totaling a <NUM> degree angular range contact in the case where opposing arc shape clamp pieces <NUM> have identical geometries. <FIG> shows another embodiment in which the arc shape clamp piece <NUM> has two angular range contacts, one each of about <NUM> degrees, thus totaling a <NUM> degree angular range contact in the case where opposing arc shape clamp pieces <NUM> have identical geometries. <FIG> shows yet another embodiment of an arc shape clamp piece <NUM>. Here, the arc shape clamp piece <NUM> has five angular range contacts, one each of about <NUM> degrees, thus totaling a <NUM> degree angular range contact in the case where opposing arc shape clamp pieces <NUM> have identical geometries. Still other embodiments may have other angular range contacts. It will be understood that opposing arc shape clamp pieces need not have the same angular range contacts, whether in the quantity or size of the arc shape clamp pieces, or the components that form the arc shape clamp pieces.

<FIG> and <FIG> show greater details of the first and second arc shape clamp pieces <NUM>, <NUM>. The first and second arc shape clamp pieces <NUM>, <NUM> include an arc shape backing piece <NUM>, <NUM> and a polymer liner <NUM>, <NUM> mounted to a radially inner wall <NUM>, <NUM> of the arc shape backing piece <NUM>, <NUM>, for example by adhesive bonding. In the illustrative embodiment, the arc shape clamp pieces <NUM>, <NUM> have identical geometries, wherein the arc shape backing pieces <NUM>, <NUM> have a one part geometry and the polymer liners <NUM>, <NUM> have a one part geometry. The identical geometries eliminate the need for extra unique component designs. It will be appreciated that the arc shape clamp pieces <NUM>, <NUM> may have different geometries, or components thereof may have some identical geometries and some different geometries.

The arc shape backing pieces <NUM>, <NUM> may be made of any suitable materials, for example, metal or metal alloy. The arc shape backing pieces <NUM>, <NUM> may be made by means of casting, machining, powdered metallurgy and/or metal injection molding. In some applications, the arc shape backing pieces <NUM>, <NUM> may be made by means of additive manufacturing.

The liners may be formed from any suitable thermoset polymer or thermoplastic polymer. The polymer material may have a low to medium coefficient of friction of about <NUM> to about <NUM>, a wear factor no less than about <NUM> E-<NUM> m2/N, a tensile strength of about <NUM> to about <NUM> psi, a coefficient of linear thermal expansion of about <NUM> to about <NUM><NUM>^-<NUM>/F, and a water absorption (<NUM>% RH) in a range of about <NUM>% to about <NUM>%. As one example, the liners may be formed from an unreinforced, semi-crystalline thermoplastic polyester based on polyethylene terephthalate (PET-P), for example, ERTALYTEO. As another example, the liners may be formed from a compression molded ultra high molecular weight polyethylene (UHMW-PE), or an extruded UHMW-PE. As another example, the liners may be formed from an injection molded acetal homopolymer, for example Delrin® 100P. Other suitable polymeric materials include polyolefins (for example, HDPE, LDPE, polypropylene), polyesters (for example, PET, PBT), acetals (for example, Delrin), polyamides (for example, Nylon), fluorinated polymers (for example, PTFE, PFA, FEP, PVDF, ETFE), vinyls (for example, PVC), acrylics (for example, PMMA), polycarbonates, polyimides (for example, PEI), polysulphones (for example, PES), among others, and blends and alloys thereof. The liners may be made by means of injection molding, machining, compression molding and/or extruding. In some applications, the liners may be made by means of additive manufacturing.

The first and second arc shape clamp pieces <NUM>, <NUM> of the embodiment shown in <FIG> and <FIG> are detachably coupled to one another by being interlocked to each other at their respective connecting ends <NUM>, <NUM>. As shown in <FIG>, the connecting ends <NUM>, <NUM> have respective first and second axially extending tabs <NUM>, <NUM> and first and second axially extending notches <NUM>, <NUM>, and are configured to be slidable axially and radially relative to one another. The interlocking split allows the first and second clamp pieces <NUM>, <NUM> to interlock when the compressive loads applied to the tabs <NUM>, <NUM> create tensile loads at the opposite end connecting ends <NUM>,<NUM> of the clamp split collar. The arc shape clamp pieces <NUM>, <NUM> are coupled together by fitting or inserting the first axially extending tab <NUM> within the second axially extending notch <NUM>, and by fitting or axially inserting the second axially extending tab <NUM> within the first axially extending notch <NUM>. Once coupled together, the connecting ends <NUM>, <NUM> form the coupling joint <NUM> that functions as the joint relative to which the arc shape clamp pieces <NUM>, <NUM> flex.

During application of a frictional braking force to the central shaft <NUM>, the axially extending tabs <NUM>, <NUM> circumferentially abut one another at respective opposite facing walls <NUM>, <NUM> to resist flexural movement of the first and second arc shape clamp pieces <NUM>, <NUM> toward each other relative to the coupling joint <NUM>. The greater the frictional braking force, the greater is the circumferentially abutting resistance load applied by one facing wall <NUM> against the opposing facing wall <NUM>.

As shown in <FIG>, the axially extending notches <NUM>, <NUM> have an angular width that is wider than the angular width of the axially extending tabs <NUM>, <NUM>. This provides an angular clearance <NUM>,<NUM> between the tabs <NUM>, <NUM> and the walls of the notches <NUM>, <NUM> to facilitate fitting or insertion of the tabs <NUM>, <NUM> within the respective notches <NUM>, <NUM>, and thus easy assembly of the interlocking split that forms the coupling joint <NUM>. The radially protruding tabs <NUM>, <NUM> are then positioned in the hub notch <NUM>. In one form, in the initial assembly of the interlocking split and insertion of the tabs <NUM>, <NUM> in the hub notch <NUM>, the axially extending tabs <NUM>, <NUM> may be circumferentially separate from one another such that the arc shape clamp pieces <NUM>, <NUM> are in an unflexed or relaxed state. In another form, in the initial assembly of the interlocking split and insertion of the tabs <NUM>, <NUM> in the hub notch <NUM>, the axially extending tabs <NUM>, <NUM> may be in circumferentially abutting relation at the opposite facing walls <NUM>, <NUM> such that the arc shape clamp pieces <NUM>, <NUM> are in a slightly flexed state. In any event, the actuator <NUM> may then be used to urge the first and second arc shape clamp pieces <NUM>, <NUM> toward one another thereby to impart the desired frictional braking force to the central shaft <NUM>. When the first and second arc shape clamp pieces <NUM>, <NUM> are urged toward each other to apply the frictional braking force to the central shaft <NUM>, the axially extending tabs <NUM>, <NUM> and thus the arc shape clamp pieces <NUM>, <NUM> engage one another and form the coupling joint <NUM> relative to which the arc shape clamp pieces <NUM>, <NUM> flex in applying the frictional braking force to the shaft <NUM>, as above described. Similarly, when the actuator <NUM> is backed off, the first and second arc shape clamp pieces <NUM>, <NUM> flex away from each other to decrease the frictional braking force applied to the central shaft <NUM>.

<FIG> shows the axially extending notches <NUM>, <NUM> are open at their radially opposite ends. This enables radial movement of the axially extending tabs <NUM>, <NUM> such that when the first and second arc shape clamp pieces <NUM>, <NUM> are urged toward each other to apply a frictional braking force to the central shaft <NUM>, the axially extending tabs <NUM>, <NUM> and thus the arc shape clamp pieces <NUM>, <NUM> shift radially relative to one another and, being in circumferentially abutting relation, engage one another and form the coupling joint <NUM> relative to which the arc shape clamp pieces <NUM>, <NUM> flex in applying the frictional braking force to the shaft <NUM>, as above described. Similarly, when the first and second arc shape clamp pieces <NUM>, <NUM> are flexed away from each other to decrease the frictional braking force applied to the central shaft <NUM>, the axially extending tabs <NUM>, <NUM> and thus the arc shape clamp pieces <NUM>, <NUM> move radially relative to one another as they unflex.

As will be appreciated, the first and second arc shape clamp pieces <NUM>, <NUM> can "float" relative to each other axially, circumferentially, and radially. As such, when the actuator <NUM> urges the radially protruding tabs <NUM>, <NUM> together to urge the arc shape clamp pieces <NUM>, <NUM> closer together or opens the deflection compensation split <NUM> to allow the arc shape claim pieces <NUM>, <NUM> to move apart, the arc shape clamp pieces <NUM>, <NUM> are able to shift to a position that is most centered and aligned with respect to the central shaft <NUM>. Thus, the floating capability enables the multi-piece split collar that is formed by the arc shape clamp pieces <NUM>, <NUM> to be self-centering and self-aligning relative to the central shaft <NUM>. This also allows for a built-in concentricity clearance between the hub <NUM> and the brake assembly <NUM>, particularly over repeated angular adjustments of the extension arm <NUM> relative to the central shaft <NUM>.

It will be appreciated that the connecting ends <NUM>, <NUM> of the first and second arc shape clamp pieces <NUM>, <NUM> need not be limited to the detachable coupling configuration shown in <FIG> and <FIG>, and other embodiments are contemplated. The first and second arc shape clamp pieces <NUM>, <NUM> may include any type of first and second axially extending protrusions that circumferentially abut one another to resist flexural movement of the first and second arc shape clamp pieces <NUM>, <NUM> toward each other relative to the coupling joint <NUM>.

<FIG>, for example, shows first and second arc shape clamp pieces <NUM>, <NUM> in which the connecting ends <NUM>, <NUM> have respective first and second axially extending tabs <NUM>, <NUM> and first and second axially extending notches <NUM>, <NUM> that are configured to be slidable axially and radially relative to one another. As will be appreciated, the chief difference between the <FIG> and <FIG> embodiments is that the tabs <NUM>, <NUM> project axially from the circumferential portions <NUM>, <NUM> in <FIG>, and the tabs <NUM>, <NUM> project radially from the circumferential portions <NUM>, <NUM> in <FIG>. The arc shape clamp pieces <NUM>, <NUM> are coupled together by fitting or inserting the first axially extending tab <NUM> within the second axially extending notch <NUM>, and by fitting or axially inserting the second axially extending tab <NUM> within the first axially extending notch <NUM>. Once coupled together, the connecting ends <NUM>, <NUM> form the aforementioned coupling joint <NUM> that functions as the joint relative to which the arc shape clamp pieces <NUM>, <NUM> flex. During application of a frictional braking force to the central shaft <NUM>, the axially extending tabs <NUM>, <NUM> circumferentially abut one another at respective opposite facing walls <NUM>, <NUM> to resist flexural movement of the first and second arc shape clamp pieces <NUM>, <NUM> toward each other relative to the coupling joint <NUM>. The greater the frictional braking force, the greater is the circumferentially abutting resistance load applied by one facing wall <NUM> against the opposing facing wall <NUM>.

The axially extending notches <NUM>, <NUM> have an angular width that is wider than the angular width of the axially extending tabs <NUM>, <NUM>. This provides an angular clearance between the tabs <NUM>, <NUM> and the walls of the notches <NUM>, <NUM> to facilitate fitting or insertion of the tabs <NUM>, <NUM> within the respective notches <NUM>, <NUM>, and thus easy assembly of the interlocking split that forms the coupling joint <NUM>. The radially protruding tabs <NUM>, <NUM> are then positioned in the hub notch <NUM>. In one form, in the initial assembly of the interlocking split and insertion of the tabs <NUM>, <NUM> in the hub notch <NUM>, the axially extending tabs <NUM>, <NUM> may be circumferentially separate from one another such that the arc shape clamp pieces <NUM>, <NUM> are in an unflexed or relaxed state. In another form, in the initial assembly of the interlocking split and insertion of the tabs <NUM>, <NUM> in the hub notch <NUM>, the axially extending tabs <NUM>, <NUM> may be in circumferentially abutting relation at the opposite facing walls <NUM>, <NUM> such that the arc shape clamp pieces <NUM>, <NUM> are in a slightly flexed state. In any event, the actuator <NUM> may then be used to urge the first and second arc shape clamp pieces <NUM>, <NUM> toward one another thereby to impart the desired frictional braking force to the central shaft <NUM>. When the first and second arc shape clamp pieces <NUM>, <NUM> are urged toward each other to apply the frictional braking force to the central shaft <NUM>, the axially extending tabs <NUM>, <NUM> and thus the arc shape clamp pieces <NUM>, <NUM> engage one another and form the coupling joint <NUM> relative to which the arc shape clamp pieces <NUM>, <NUM> flex in applying the frictional braking force to the shaft <NUM>, as above described. Similarly, when the actuator <NUM> is backed off, the first and second arc shape clamp pieces <NUM>, <NUM> flex away from each other to decrease the frictional braking force applied to the central shaft <NUM>.

Further, the axially extending notches <NUM>, <NUM> are open at their radially opposite ends. This enables radial movement of the axially extending tabs <NUM>, <NUM> such that when the first and second arc shape clamp pieces <NUM>, <NUM> are urged toward each other to apply a frictional braking force to the central shaft <NUM>, the axially extending tabs <NUM>, <NUM> and thus the arc shape clamp pieces <NUM>, <NUM> shift radially relative to one another and, being in circumferentially abutting relation, engage one another and form the coupling joint <NUM> relative to which the arc shape clamp pieces <NUM>, <NUM> flex in applying the frictional braking force to the shaft <NUM>, as above described. Similarly, when the first and second arc shape clamp pieces <NUM>, <NUM> are flexed away from each other to decrease the frictional braking force applied to the central shaft <NUM>, the axially extending tabs <NUM>, <NUM> and thus the arc shape clamp pieces <NUM>, <NUM> move radially relative to one another as they unflex.

<FIG> shows another embodiment. Here, first and second arc shape clamp pieces <NUM>, <NUM> are detachably coupled to one another by a hinge <NUM>, a pin <NUM> in the illustrative embodiment, at the respective connecting ends <NUM>, <NUM>. The arc shape clamp pieces <NUM>, <NUM> are coupled together by interlocking hinge prongs <NUM>, <NUM> and sliding the pin <NUM> axially into holes <NUM>, <NUM> in the respective prongs <NUM>, <NUM>. Once coupled together, the connecting ends <NUM>, <NUM> form the coupling joint <NUM> that functions as the joint relative to which the arc shape clamp pieces <NUM>, <NUM> flex. During application of a frictional braking force to the central shaft <NUM>, the pin <NUM> holds the hinge prongs <NUM>, <NUM> circumferentially together to resist flexural movement of the first and second arc shape clamp pieces <NUM>, <NUM> toward each other relative to the coupling joint <NUM>. The greater the frictional braking force, the greater is the resistance load by the pin <NUM> against the opposing hinge prongs <NUM>, <NUM>. As will be appreciated, axial, circumferential and radial clearances can be built into the holes <NUM>, <NUM> to enable respective axial, circumferential and radial shifting between the arc shape clamp pieces <NUM>, <NUM>, in substantially the same manner as the embodiments of <FIG> and <FIG>.

Referring now to <FIG>, there is shown a flowchart <NUM> of a method of installing a brake assembly in a medical device support system, such as the brake assembly <NUM> in the medical device support system <NUM> of <FIG>. At step <NUM>, the first and second discrete arc shape clamp pieces <NUM>, <NUM> of the brake assembly <NUM> are provided at one side of the central shaft <NUM>, for example, in a position radially outward of the central shaft <NUM>. This may be in a health treatment room such as a surgery room, for example, where the central shaft <NUM> is made accessible for example by an access opening <NUM> as shown in <FIG>. At step <NUM>, either the connecting ends <NUM>, <NUM> or the free ends <NUM>, <NUM> of the first and second discrete arc shape clamp pieces <NUM>, <NUM> are moved around the central shaft <NUM> to an opposite side of the central shaft <NUM> so that the connecting ends <NUM>, <NUM> and free ends <NUM>, <NUM> are situated at opposite sides of the central shaft <NUM>. At step <NUM>, the connecting ends <NUM>, <NUM> are coupled together for flexural movement relative to the coupling joint <NUM> at the connecting ends <NUM>, <NUM> and for free movement at the free ends <NUM>, <NUM>. At step <NUM>, the first and second arc shape clamp pieces <NUM>, <NUM> are arranged relative to the central shaft <NUM> to respectively increase and decrease a frictional braking force to the central shaft <NUM> in response to flexural movement of the first and second arc shape clamp pieces <NUM>, <NUM> relative to the coupling joint <NUM>. At step <NUM>, the brake assembly <NUM> is secured in the hub <NUM> of the extension arm <NUM> for rotation with the extension arm <NUM> about the central shaft <NUM>.

The arranging step can include arranging the first and second arc shape clamp pieces <NUM>, <NUM> to form a multi-piece split collar around the central shaft <NUM> that is configured to contract and expand relative to the central shaft <NUM> in response to flexural movement of the first and second arc shape clamp pieces <NUM>, <NUM> relative to the coupling joint <NUM>. The multi-piece collar can be any number of clamp pieces and need not be limited to two clamp pieces. The coupling step can include interlocking the connecting ends <NUM>, <NUM> of the first and second arc shape clamp pieces <NUM>, <NUM>. The coupling step can include sliding the first and second arc shape clamp pieces <NUM>, <NUM> axially relative to one another, as in the embodiments of <FIG> and <FIG>. The coupling step can include hingedly connecting the connecting ends <NUM>, <NUM> of the first and second arc shape clamp pieces <NUM>, <NUM>, as in the embodiment of <FIG>. The method can further include mounting a retaining snap ring in a groove in the central shaft <NUM> to axially retain the first and second arc shape clamp pieces onto the central shaft <NUM>.

Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings, as long as the alterations remain within the scope of the appended claims.

Claim 1:
A brake assembly (<NUM>) for a medical device support system (<NUM>) having a central shaft (<NUM>), the brake assembly comprising:
first and second discrete arc shape clamp pieces (<NUM>, <NUM>) that are detachably coupled to one another at one end (<NUM>, <NUM>) for flexural movement relative to a coupling joint (<NUM>) and that are free at an opposite end (<NUM>, <NUM>),
wherein the first and second arc shape clamp pieces are configured to flex relative to the coupling joint toward and away from each other to respectively increase and decrease a frictional braking force to the central shaft.